Aws Wj 201203

March 2012

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CONTENTS

March 2012 • Volume 91 • Number 3

AWS Web site www.aws.org

Features 32

32

43

Undertaking a Complex Underwater Repair A cargo ship filled with iron ore suffered extensive damage from a grounding, but was put back together again by an underwater repair team D. Phillips

40

FABTECH Comes to Canada This popular all-inclusive fabricating and welding exhibition opens up to a Canadian audience

43

Welded Aluminum on Ships — An Overview As shipbuilding techniques evolved, so did the use of aluminum G. A. Mirgain

48

Build Your Own Campfire Grill This do-it-yourself project has everything you need to know to get started B. Pelky

51

New AWS Spec Details Flux Cored and Metal Cored Electrodes A new filler metal classification system addresses the new generation of flux cored and metal cored electrodes D. Crockett

The American Welder

93

91

How to Pick the Right-Sized Welding Cable A formula is given to calculate a safe size welding cable, depending on the current used and distance from the power source A. F. Manz

93

Welded Benches for Fun and Fund-Raising Whimsical garden benches were designed and fabricated to help raise funds for a project in Guatemala H. Woodward

Departments Editorial ............................4 Press Time News ..................6 News of the Industry ..............8 International Update ............12 Stainless Q&A ....................14 RWMA Q&A ......................20 Point of View ....................24 Product & Print Spotlight ......26 Conferences ......................60 Coming Events....................62 Certification Schedule ..........64 Society News ....................73 Tech Topics ......................74 Guide to AWS Services ........84 Personnel ........................88 American Welder Learning Track ..................96 Fact Sheet......................100 Classifieds ......................106 Advertiser Index ................108

Welding Research Supplement 65-s

Continuous Cooling Transformation Behavior in the CGHAZ of Naval Steels Transformation diagrams were developed for the coarse-grain heat-affected zone of HSLA-65, HSLA-100, and HY-100 steels X. Yue et al.

74-s

Developing an Alternative Heat Indexing Equation for FSW A heat transfer model was developed to help predict the correlation between weld tool geometry and process parameters J. A. Querin and J. A. Schneider

81-s

Improving Supermartensitic Stainless Steel Weld Metal Toughness Experiments were conducted to achieve weld metal toughness improvements through varying postweld heat treatments S. Zappa et al.

89-s

Welding Journal (ISSN 0043-2296) is published monthly by the American Welding Society for $120.00 per year in the United States and possessions, $160 per year in foreign countries: $7.50 per single issue for domestic AWS members and $10.00 per single issue for nonmembers and $14.00 single issue for international. American Welding Society is located at 550 NW LeJeune Rd., Miami, FL 33126-5671; telephone (305) 443-9353. Periodicals postage paid in Miami, Fla., and additional mailing offices. POSTMASTER: Send address changes to Welding Journal, 550 NW LeJeune Rd., Miami, FL 33126-5671. Canada Post: Publications Mail Agreement #40612608 Canada Returns to be sent to Bleuchip International, P.O. Box 25542, London, ON N6C 6B2 Readers of Welding Journal may make copies of articles for personal, archival, educational or research purposes, and which are not for sale or resale. Permission is granted to quote from articles, provided customary acknowledgment of authors and sources is made. Starred (*) items excluded from copyright.

Ultrasonic Wave Assisted GMAW Metal transfer showed improvement with the application of an auxiliary detaching force Y. Y. Fan et al.

On the cover: A Hydrex senior diver/welder/technician welds a longitudinal stiffener on the side of the Eleftheria K in October 2011 as part of a major repair after the ship had grounded off the Suez Canal. (Photo copyright 2011, Hydrex.)

WELDING JOURNAL

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EDITORIAL Founded in 1919 to Advance the Science, Technology and Application of Welding

Let’s Celebrate Women in Welding Welding, brazing, and soldering are great careers for women. You and I know it, but for most people, it is a well-kept secret. I want to change that perspective, and one way we can do that is for all of us to celebrate women in welding. While the image of welding is improving, the general public often thinks of welding as a man wearing a helmet working in a rough and dirty environment. . . Boo, hiss! As people are learning, the pay is very good, and there are many career opportunities associated with welding, brazing, and soldering. These include welder, Certified Welding Inspector, welding technician, welding engineer, and welding distributor. And those are just a few of the many opportunities. Others include brazer, welding or brazing operator, robotic or semiautomatic welding operator, brazing and soldering engineer, welding salesperson, and welding or brazing artist. All are open to both men and women, and more and more women are “joining” in. (Pun intended.) There are many misconceptions women may have about welding. Following are just a few. 1. All welding professionals work under a helmet (which makes for a bad hair day). While a helmet is necessary for watching the arc, much needs to be done before and after the arc is struck. Choice of materials and process, cleanliness and preparation of the joint, design, testing, and qualification all require the working knowledge of the welding or brazing professional, and much of that work is accomplished without a welding helmet. 2. Welding is done in a rough and dirty place. These days, much welding and brazing is performed under clean conditions, and many workplaces that were once very dirty have now been cleaned up. Welding schools strive to ingrain in their students that it is important to keep their workplace picked up and clean. It is easier to produce a clean, quality weld if the environment in which it is made is the same. It’s true, huge parts are welded and welding may be done outdoors such as at construction sites; however, welding and brazing are also done on small parts in clean and precisely controlled environments. 3. Women don’t like arcs and sparks. Maybe some don’t, just as some men don’t. But others do. Arcs and sparks make for an exciting place to work. However, much of welding and brazing are done automatically or semiautomatically, which frequently allows the operator to stand clear of the process. That type of welding still needs a person to set it up and make sure the welding is done properly, but the operator can usually step away and not be exposed to the arcs and sparks, particularly with processes that have flux covering the weld pool. Other examples are robotic welding operations, which for safety sake require the operator to stay clear of the robot’s operation. If you’re a welding engineer, you are designing, specifying, and overseeing the work, not making the arc and sparks yourself. However, if you like arcs and sparks, there are plenty of opportunities for that, too. If you are a woman involved with any part of our profession, I would like to learn about you and what you do. As I travel as your AWS president next year, I hope to spread the word and celebrate women in welding, brazing, and soldering, and show that these are open and viable fields for women. It will help to share stories of women in a variety of joining careers and to have the statistics to show that women’s presence in our industry is not an anomaly. If you would like me to share your story, please e-mail a short description (my suggestion is 200 words or less) to [email protected] or mail it to Nancy Cole, American Welding Society, 550 NW LeJeune Rd., Miami, FL 33126. If possible, please also send a photo of yourself, preferably taken at your workplace. With you, I look forward to celebrating women in welding.

Nancy C. Cole AWS Vice President

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Officers President William A. Rice Jr. OKI Bering Vice President Nancy C. Cole NCC Engineering Vice President Dean R. Wilson Kimberly-Clark Global Safety Vice President David J. Landon Vermeer Mfg. Co. Treasurer Robert G. Pali J. P. Nissen Co. Executive Director Ray W. Shook American Welding Society

Directors T. Anderson (At Large), ITW Global Welding Tech. Center J. R. Bray (Dist. 18), Affiliated Machinery, Inc. J. C. Bruskotter (Past President), Bruskotter Consulting Services G. Fairbanks (Dist. 9), Fairbanks Inspection & Testing Services T. A. Ferri (Dist. 1), Thermadyne Industries D. A. Flood (Dist. 22), Tri Tool, Inc. R. A. Harris (Dist. 10), Consultant D. C. Howard (Dist. 7), Concurrent Technologies Corp. J. Jones (Dist. 17), Thermadyne Industries W. A. Komlos (Dist. 20), ArcTech, LLC R. C. Lanier (Dist. 4), Pitt C.C. T. J. Lienert (At Large), Los Alamos National Laboratory J. Livesay (Dist. 8), Tennessee Technology Center M. J. Lucas Jr. (At Large), Belcan Corp. D. E. Lynnes (Dist. 15), Lynnes Welding Training C. Matricardi (Dist. 5), Welding Solutions, Inc. D. L. McQuaid (At Large), DL McQuaid & Associates J. L. Mendoza (Past President), Lone Star Welding S. P. Moran (At Large), ESAB Welding & Cutting Products K. A. Phy (Dist. 6), KA Phy Services, Inc. W. R. Polanin (Dist. 13), Illinois Central College R. L. Richwine (Dist. 14), Ivy Tech State College D. J. Roland (Dist. 12), Marinette Marine Corp. N. Saminich (Dist. 21), Desert Rose H.S. and Career Center N. S. Shannon (Dist. 19), Carlson Testing of Portland T. A. Siewert (At Large), NIST (ret.) H. W. Thompson (Dist. 2), Underwriters Laboratories, Inc. R. P. Wilcox (Dist. 11), ACH Co. M. R. Wiswesser (Dist. 3), Welder Training & Testing Institute D. Wright (Dist. 16), Zephyr Products, Inc.

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PRESS TIME NEWS AWS Careers in Welding Trailer Makes Appearance at Michigan Governorʼs State Address The AWS Careers in Welding Trailer, on display in front of Michigan’s State Capitol on January 18, served as a nice complement to Governor Rick Snyder’s State of the State address. The exhibit attracted guests throughout the day with messages about how young people who choose oftenlucrative welding careers can fill a crucial gap in the economy. “We need to do a much better job with connecting our workforce development efLegislators along with students toured the forts with our community colleges and ecoAWS Careers in Welding Trailer, shown here nomic development organizations,” Snyder against the backdrop of Michigan’s State said. He spent much of the day promoting Capitol, during the day of Governor Rick Sny- the job-training and placement initiatives he proposed in December. der’s State of the State address. “Not only do Michigan employers have difficulty filling jobs today, but if we do not act, they will tomorrow as well,” Snyder said at the time. “Engineers, nurses, welders, and a number of trades face significant staffing challenges.” By the year 2019, welding will have an estimated shortfall of 240,000 skilled workers in the United States. Michigan alone has an estimated demand of nearly 70,000 welding professionals that is not met by the supply. During the recent event, nearly 100 attendees from representatives and senators to welding students toured the 53-ft, single-expandable trailer designed and built by MRA Experiential Tours & Equipment, Madison Heights, Mich. Its 650-sq-ft of exhibit space features VRTEX® 360 virtual reality arc welding training stations by The Lincoln Electric Co., Cleveland, Ohio; interactive educational exhibits; a “Day in the Life of a Welder” display; a life-size welder highlighting welding as a safe profession; a social media kiosk; and welding scholarship details. “I was delighted to hear many of the legislators talk about skill training, and I hope they incorporate those thoughts into educational funding,” said Sam Gentry, executive director, AWS Foundation. Also present at the address was Monica Pfarr, corporate director, workforce development, AWS.

Mobile App Introduced for IIWʼs 2012 Summit For the first time, the International Institute of Welding (IIW) Annual Assembly and International Conference has gone mobile. At the summit, set for July 8–14, 2012, in Denver, Colo., a smartphone mobile app called “IIW 2012” will give attendees a convenient way to navigate the event. The app provides participants with necessary information, including speaker lists, floor plan maps, and an interactive schedule. In addition, it allows social media interaction with a live feed of Tweets and a photo gallery where attendees can A smartphone mobile app has been snap pictures and upload for all to see. The app created for the International Institute is available for iPhone, Blackberry, and Google of Welding’s 65th Annual Assembly to Android phones. To download, visit be held this year from July 8 to 14 in www.iiw2012.com/phone_app.html. Denver, Colo. The 2012 IIW Annual Assembly will be officially hosted by the IIW American Council, which consists of the American Welding Society (AWS), the Edison Welding Institute, and the Welding Research Council. The conference is in its 65th year, but it has only been held in the United States three times, most recently in 1997. AWS has organized a planning committee of American Council members and other welding experts co-chaired by Damian Kotecki and Tom Mustaleski, both AWS past presidents. Dr. Kotecki is IIW treasurer and AWS Executive Director Ray Shook currently serves as IIW vice president. For more information, visit www.iiw2012.com.◆ 6

MARCH 2012

Publisher Andrew Cullison Editorial Editorial Director Andrew Cullison Editor Mary Ruth Johnsen Associate Editor Howard M. Woodward Associate Editor Kristin Campbell Peer Review Coordinator Melissa Gomez Publisher Emeritus Jeff Weber Design and Production Managing Editor Zaida Chavez Senior Production Coordinator Brenda Flores Advertising National Sales Director Rob Saltzstein Advertising Sales Representative Lea Paneca Senior Advertising Production Manager Frank Wilson Subscriptions Subscriptions Representative Sylvia Ferreira [email protected] American Welding Society 550 NW LeJeune Rd., Miami, FL 33126 (305) 443-9353 or (800) 443-9353 Publications, Expositions, Marketing Committee D. L. Doench, Chair Hobart Brothers Co. S. Bartholomew, Vice Chair ESAB Welding & Cutting Prod. J. D. Weber, Secretary American Welding Society T. Birky, Lincoln Electric Co. D. Brown, Weiler Brush J. Deckrow, Hypertherm D. DeCorte, RoMan Mfg. J. R. Franklin, Sellstrom Mfg. Co. F. H. Kasnick, Praxair D. Levin, Airgas E. C. Lipphardt, Consultant R. Madden, Hypertherm D. Marquard, IBEDA Superflash J. Mueller, Thermadyne Industries J. F. Saenger Jr., Consultant S. Smith, Weld-Aid Products N. C. Cole, Ex Off., NCC Engineering J. N. DuPont, Ex Off., Lehigh University L. G. Kvidahl, Ex Off., Northrup Grumman Ship Systems S. P. Moran, Ex Off., ESAB Welding & Cutting Prod. E. Norman, Ex Off., Southwest Area Career Center R. G. Pali, Ex Off., J. P. Nissen Co. R. Ranc, Ex Off., Superior Products W. A. Rice, Ex Off., OKI Bering R. W. Shook, Ex Off., American Welding Society D. Wilson, Ex Off., Kimberly-Clark Global Safety Copyright © 2012 by American Welding Society in both printed and electronic formats. The Society is not responsible for any statement made or opinion expressed herein. Data and information developed by the authors of specific articles are for informational purposes only and are not intended for use without independent, substantiating investigation on the part of potential users.

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NEWS OF THE INDUSTRY

Maritime Advances Sail Strong Northeast Wisconsin Technical College, Marinette Marine to Train Shipbuilders

fourth of six new apprenticeship programs to be developed through the $6 million Sectors Alliance for the Green Economy project grant from the U.S. Department of Labor.

National Initiative Launched by Maritime Industry Leaders The Lighthouse Campaign, launched officially at the Shipbuilders Council of America’s fall meeting last year, recently sent representatives to a meeting at the National Center for Construction Education and Research headquarters in Alachua, Fla., to finalize plans for developing a national Maritime Workforce Development program and establishing the National Maritime Education Council to provide program oversight. The council will meet this month in Mobile, Ala., in conjunction with the Gulf States Shipbuilders Consortium’s 2012 annual meeting, where its interim board is expected to draft bylaws, form committees, and formalize the group’s structure.

Daigle Welding & Marine Chosen for Constructing the NPA Osprey Recently, Northeast Wisconsin Technical College (NWTC) and Marinette Marine signed a two-year contract to provide shipbuilding skills and talent. The above welding image was taken at the Aluminum Center of Excellence (ACE) Marine in Green Bay, Wis.; both ACE Marine and Marinette Marine are part of the Fincantieri Marine Group. (Photo courtesy of CJ Janus/NWTC.)

Hundreds of current and future shipbuilders will be trained in Marinette, Wis., thanks to a contract signed by Northeast Wisconsin Technical College (NWTC) and Marinette Marine Corp. Through the two-year agreement, the college will provide 130,000 hours of training to Marinette Marine’s new hires and incumbent workers. Focusing on shipfitters, welders, pipefitters, and electricians, training will be provided at the NWTC Marinette campus and the new North Coast Marine Manufacturing Center along with Marinette Marine facilities. The college has hired a training center coordinator and several instructors to work with area marine and general manufacturing employers. The signing signifies a forward step for the Wisconsin/Michigan region’s growing shipbuilding industry. Changing workforce demographics and skilled worker shortages in nearly all areas of the industry prompted marine manufacturers to join together with NWTC and two additional higher education institutions to form the North Coast Marine Manufacturing Alliance. Working with the alliance’s shipbuilding companies, the college created marine manufacturing training options beyond incumbent worker training, offering a marine construction technical diploma and marine engineering technology associate degree programs. For more information, visit www.nwtc.edu/marine. Also, in related news, NWTC and the Department of Workforce Development’s Bureau of Apprenticeship Standards introduced a welder-fabricator apprenticeship program in Green Bay, Wis. Structured for four years, it includes 7560 hours of on-thejob learning plus 440 hours of related instruction. This is the 8

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A new 39-ft multitask vessel will be fabricated by Daigle Welding & Marine for the Nanaimo Port Authority (NPA). Shown here is the authority testing its new firefighting equipment on the NPA Eagle.

The Nanaimo Port Authority (NPA) selected Daigle Welding & Marine Ltd., both of B.C., Canada, to design and build its new EagleCraft 39-ft boat, the NPA Osprey. Designed by Steve Daigle and his naval architect Felipe Garcia, the multitask vessel will serve as a pilot/fire boat, patrol vessel, and water ambulance for the Port of Nanaimo. It is expected to be in service this spring. The NPA Osprey is the second vessel the authority has purchased in the past year from Daigle Welding & Marine. The NPA Eagle, a 32-ft smaller version, recently had a 110-hp diesel fire pump installed with monitors on the bow and stern. “Having two near-sister vessels will provide operational effi-

ciencies from a critical spares and training perspective,” said Edward Dahlgren, NPA.

Navy Metalworking Center to Improve Doors on Littoral Combat Ship The Navy Metalworking Center started a Navy ManTech project that will employ design for manufacturing and assembly principles, lean manufacturing, and other solutions to reduce the weight and cost of sliding doors on the Freedom Class Littoral Combat Ship. These entrances are challenging to make, requiring several welds accomplished in a labor-intensive manner. The project will evaluate the current door configuration and manufacturing approach, plus recommend improvements. The integrated project team will also evaluate and down-select proposals. Enhancements to be considered include using metallic sandwich structures; automated or lower heat input welding; improved fixturing, part and process consolidation, and simplification; and modular assembly. After subscale testing, the team’s suggestions will be prototyped and demonstrated.

Brazil Acquires Three Ocean Patrol Vessels The Brazilian Navy signed a contract worth approximately $209.5 million with BAE Systems, London, UK, for the supply of three ocean patrol vessels and ancillary support services. The contract also contains a manufacturing licence to enable additional vessels of the same class to be constructed in Brazil. The three, 295-ft vessels, originally constructed for the government of Trinidad and Tobago, will provide the Brazilian Navy with enhanced maritime capability in the near term, pending the

The vessels bought by the Brazilian Navy will provide enhanced maritime capability in the near term. Displayed is the Port of Spain on sea trials. (Copyright© 2010 BAE Systems. All rights reserved.) acquisition of future ships under its Prosuper program. The first two ships will be delivered this year; the third will follow in early 2013. The ocean patrol vessels are capable of speeds in excess of 25 knots and weigh 2200 tons fully loaded. With a 30-mm cannon and two 25-mm guns, as well as a helicopter flight deck and inflatable boat, they will be useful for performing maritime security roles in Brazil’s territorial waters. They are designed to accommodate a 70-member crew, with extra accommodation for 50 embarked troops or passengers, and are effective for search/rescue and disaster-relief operations.

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WELDING JOURNAL

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Stevens Welding Shop Achieves Milestone

Owner Duane Stevens, who has been an AWS member for 27 years and serves as treasurer of the AWS Mid-Plains Section, started the company when he was 19 years old. Today, he still operates as a one-man shop but hires an extra hand as required for completing bigger projects. He assists the local farm and ranch community by making machinery repairs, building feed bunks and bale feeders, and fabricating panels for hog confinements. His range of services include gas metal arc, shielded metal arc, and gas tungsten arc welding; brazing; and plasma cutting. He travels with portable equipment to work sites, too. “They’re different all the time. You’re learning every day,” Stevens said of the jobs he receives. He added that it is satisfying to know he helps people. An event to commemorate the company’s 40th anniversary, held earlier this year at the community center across the street from the welding shop, attracted 170 attendees. Among the individuals present from the AWS Mid-Plains Section were Chair Dan Rucker and member Rex Cross. Also on hand was Duane’s welding instructor, Latham Mortensen, from Central Community College, Hastings, Neb.

FMA Forms Green Manufacturer Network

Latham Mortensen (left), a welding instructor at Central Community College, and Duane Stevens, owner of Stevens Welding Shop, pose in front of a banner honoring the company’s 40th anniversary. Stevens Welding Shop, situated in the small town of Sumner, Neb., is currently celebrating 40 years in business.

The Fabricators & Manufacturers Association, Int’l (FMA), Rockford, Ill., invites manufacturing executives to join its new Green Manufacturer Network, an organization of individual members working together to drive the transition toward environmentally friendly manufacturing. Members receive discounts on conferences, workshops, and webinars; event announcements and topical discussions; and access to sustainability resources. Joining the network costs $150. Members will also be able to share knowledge on sustainable manufacturing and promote

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Pendarvis Manufacturing Celebrates Its 30-Year Anniversary

ice for 30 years. Founded by Robert “Bud” Pendarvis and now managed by his sons, Brian and Robert, the company has expanded its capabilities to meet the increased demand for custom manufacturing services in the southern California area. “In the last 30 years, we have grown from a 2400-sq-ft building with two employees to more than 14,000-sq-ft of manufacturing space, with more than 20 shop employees and two engineers,” said Brian Pendarvis. The company offers turnkey precision machining, metal fabrication, welding, and assembly services, and manufactures parts up to 10 tons. Pendarvis has also increased its base to serve various industries in the area, including aerospace, transportation, instrumentation, research, defense, solar energy, architectural, and specialty as well as sewage treatment equipment.

Caterpillar, Lincoln Partner with School to Increase Students’ Interest in Skilled Trades

Pendarvis Manufacturing has been in operation for 30 years serving southern California. Pictured is a group shot taken in front of a truck loaded with a large steel project.

Caterpillar, Peoria, Ill., and The Lincoln Electric Co., Cleveland, Ohio, partnered with Pulaski High School, Milwaukee, Wis., to increase the interest of young adults in skilled trades at manufacturing companies focusing on welding operations. “We wanted to drive interest for kids in skilled trades and show them that this is a good occupation. We communicated, ‘This is a skill that can never be taken away from you once you learn it,’” said Adam Schrank, weld/fabrication group manager. Work started last year when John Losineki, now a retired industrial arts teacher at the school, approached Caterpillar to see

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— continued on page 104

WELDING JOURNAL

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INTERNATIONAL UPDATE Kennametal to Buy UK-Based Deloro Stellite Group Kennametal, Inc., Latrobe, Pa., recently announced it will buy the Deloro Stellite Group from Duke Street Capital for approximately $366.9 million. It is the company’s first acquisition in more than two years. Deloro Stellite is a global manufacturer of alloy-based critical wear solutions for extreme environments involving high temperature, corrosion, and abrasion. Based in the UK, the company employs approximately 1300 people at seven primary operating facilities around the world, including locations in the United States, Canada, Germany, Italy, India, and China. The company has approximately $292.7 million in annual sales. The acquisition remains subject to customary regulatory approval and negotiated conditions for closing.

UK Manufacturer Adds Robots to Increase Capacity and Ease Strain on Welders Valen Fittings, a manufacturer of pipefittings in the United Kingdom, recently installed two Fanuc robots to increase production capacity and to remove the physical strain manual plasma arc cutting and welding places on its workers. The company manufacturers butt-joint weld fittings for the oil and gas industry from a wide of range of materials, none of which are ferrous. Currently, 37 materials are used. Sizes range from 8 to 48 Valen Fittings recently installed two robots in. in diameter. Some at its facility. Automating the company’s fittings require a cutting and welding operations proved welder to weld continchallenging because of the many types of uously for up to 15 min. “We continuously aim fittings the company makes, types of material used, range of thicknesses, and low to improve productivity but because of the many volume. fittings, types of material, range of thicknesses, and low volume call off, we don’t have the luxury of being able to implement basic welding robot principles,” said Len Sandford, Valen managing director. “Our aim is always to adapt our existing manning skills so we can maintain the quality and reduce operator strain.” The company worked with welding automation specialist Pentangle Engineering and first addressed the issue of accurately plasma cutting part finished pressings. A Fanuc Robotics M-16 iB, inverted on a jib, is used to plasma cut edges and then cut a weld preparation angle along the same edge. The second robot, a 6-axis ARC Mate 120-iC positioned with a single-axis manipulator, is used to weld prepared sections. “Our overall productivity has improved since the installation of the robots,” Sandford concluded. “They provide more consis-

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MARCH 2012

tency, and the quality they deliver is faultless. From a project point of view, we knew what we wanted to achieve — we didn’t want a large team looking after each cell — we wanted a simple, one-man operation that allowed our existing skilled operators to have a simpler, safer, cleaner, and less stressful way to work. And we believe we’ve achieved that.”

Mitsubishi Motors to Stop Building Cars in Europe by 2013 Mitsubishi Motors Corp., Tokyo, Japan, recently announced it will stop production of automobiles at its subsidiary European production site Netherlands Car B.V. (NedCar) beginning in 2013. NedCar currently produces Colt and Outlander models designated for sales in the company’s European market. The move is believed to be the first withdrawal from Europe by a major Japanese car maker. NedCar was established in 1991, and has produced 1.1 million Mitsubishi vehicles since that time. However, its output never reached its production capacity of 200,000 units a year. The production plant in Born, The Netherlands, will be sold. The plant employs 1500 workers. Production and delivery of Mitsubishi models for Europe from Japan and Thailand will continue.

Final Sections Joined in France for Brazil’s First Scorpene Submarine The 12 welders of the French-Brazilian team recently started final operations at the DCNS Group’s facility in Cherbourg, France, for joining the sections of the first Scorpene submarine for Brazil. The operation consists of A DCNS worker monitors welding opera- welding the rings tions for assembling the rings forming the forming the forward forward part of the first submarine for part of the submarine. The resulting Brazil. assembly, around 6 m in diameter, 24 m long, and weighing 200 tons, will subsequently accommodate systems including the operations center, the torpedoes, and utilities such as water, gas, and electricity. Throughout the first half of this year, the tanks and large structures will be added to the hull as well as the bridge fin, ballast tanks, access trunk, and fresh-air induction cupola. The next assembly operation will take place in Brazil. As part of the technology transfer, the Brazilian welders have received three months of training so that they could obtain the required qualifications. The contract covers the design and construction of four conventional submarines with technology transfer. The Cherbourg center is currently hosting 36 Brazilian trainees, bringing the number of trainees to 115 since the start of the contract. The DCNS Group, headquartered in Paris, France, is contracted to assist with the design and construction of the nonnuclear part of the first Brazilian nuclear-powered submarine, and support for the construction of a naval base and a shipyard. The first of the four conventional submarines covered in the contract is scheduled to enter active service in 2017.♦

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STAINLESS Q&A

BY DAMIAN J. KOTECKI

Q: We have a customer who wants us to build a thin-wall (1⁄4-in.) vessel out of 316H to be used in service at 1000°F. Apparently this is for a test that they expect will run for five years. Of course they’re concerned with welding consumables having 0.04 to 0.05% carbon and ferrite less than 5 FN, and suggested we use 316Ti. To my knowledge, transferring Ti can be an issue, and I’m wondering if 318 would be a good choice. A: First of all, 316Ti is not a designation for an AWS-classified filler metal as either a bare wire in AWS A5.9/A5.9M nor as a covered electrode in AWS A5.4/A5.4M. It is also not a designation in the corresponding ISO 14343 or ISO 3581 standards, respectively. It may be a designation indicating addition of titanium to a 316 composition, but I do not know for sure to what your customer is referring. You can find Asian products identified as ER316Ti on the Internet, but there is no connection to AWS specifications. On the other hand, 318 designates filler metal that is similar to 316 except that it has an addition of niobium (Nb). Niobium is a stabilizing element, just like titanium. Both alloy elements are used to prevent

Fig. 1 — The iso-ferrite lines are labeled with the expected Ferrite Number, while solidification modes are indicated by “A” as 100% austenite solidification for compositions above the 0 FN line, “AF” as primary austenite solidification for compositions below the 0 FN line to the first dashed line, “FA” as primary ferrite solidifacation for compositions between the two dashed lines, and “F” as 100% ferrite solidification below the second dashed line.

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14

MARCH 2012

Table 1 — 316H, 318, and 16-8-2 Composition Limits AWS Standard

A5.4

A5.9

Class

Chemical Composition, wt-% (Single value is a maximum.) P S Si Cr Ni Mo

C

Mn

E316H-XX

0.04 to 0.08

0.5 to 2.5

0.04

0.03

1.00

17.0 to 20.0

11.0 to 14.0

2.0 to 3.0

0.75

—

E318-XX

0.08

0.5 to 2.5

0.04

0.03

1.00

17.0 to 20.0

11.0 to 14.0

2.0 to 3.0

0.75

6x%C to 1.00

E16-8-2-XX

0.10

0.5 to 2.5

0.03

0.03

0.60

14.5 to 16.5

7.5 to 9.5

1.0 to 2.0

0.75

—

ER316H

0.04 to 0.08

1.0 to 2.5

0.03

0.03

0.30 to 0.65

18.0 to 20.0

11.0 to 14.0

2.0 to 3.0

0.75

—

ER318

0.08

1.0 to 2.5

0.03

0.03

0.30 to 0.65

18.0 to 20.0

11.0 to 14.0

2.0 to 3.0

0.75

8x%C to 1.0

ER16-8-2

0.10

1.0 to 2.0

0.03

0.03

0.30 to 0.65

14.5 to 16.5

7.5 to 9.5

1.0 to 2.0

0.75

—

chromium carbide precipitation, and thereby prevent sensitization. However, it is time for a reality check: At 1000°F (540°C), the 316H base metal will become completely sensitized regardless of the filler metal used. So there is no point being concerned about sensitization in the filler metal. Furthermore, sensitization is of no concern in high-temperature service. Sensitization is an issue in ambient-temperature corrosion resistance, not in high-temperature service. I would not recommend 318 filler metal with less than 5 FN because niobium enhances susceptibility to solidification cracking at low ferrite levels. 316H filler metal would be more resistant to solidification cracking at low FN than would be 318 filler metal. But there is a still better choice than 316H filler metal for service at 1000°F, especially if you must have weld metal below 5 FN. That better choice is the largely overlooked 16-8-2 composition, and, though it may take a bit of looking to find a supplier, it is generally made with less than 5 FN. The 16-8-2 composition is highly resistant to solidification cracking at very low ferrite content. Table 1 compares the AWS composition limits for 316H, 318, and 16-8-2 filler metals as covered electrodes and as bare wires. It is noteworthy that the 16-8-2 composition is considerably lower in alloy content than the 316H and 318 compositions. This is important for two reasons. The first is that, beginning from the same ferrite level, 16-8-2 weld metal is much more resistant to formation of sigma phase at elevated temperatures like 1000°F than is either 316H or 318 weld metal. With lesser sigma formation, the creep behavior of 16-8-2 weld metal is improved. As noted by Marshall and Farrar (Ref. 1), these special properties of 16-8-2 weld metal have resulted in the ASME Code allocating higher stress-rupture factors to 16-8-2 weld metal than to 308- and 316-type weld metals. The second reason is that, as a result of

lower total alloy content, 16-8-2 weld metal requires less ferrite in order to obtain primary ferrite solidification, which in turn provides maximum resistance to solidification cracking. The WRC-1992 Diagram (Fig. 1) shows that the boundary below which primary ferrite solidification is obtained is tilted somewhat relative to the iso-ferrite lines. So 16-8-2 weld metal, with a chromium equivalent of about 17 or a bit less, will solidify as primary ferrite with even less than 1 FN, while 316H weld metal, with a chromium equivalent of above about 20, requires at least 3 FN to solidify as primary ferrite. Marshall and Farrar (Ref. 1) describe 16-8-2 as the “overlooked or neglected” austenitic stainless steel weld metal. I agree with that description. Weld metal of 16-8-2 type was studied rather extensively during the 1960s through the 1980s when power-generating plants were being extensively built in the United States — see, for example, Klueh and Edmonds (Ref. 2). Today, because there has been so little power-generating plant construction over the last 20 years, there are not a lot of manufacturers of this filler metal composition, but it remains available. I would suggest

Cu

Nb

that this is the best filler metal choice for welding your 316H vessel.◆ References 1. Marshall, A. W., and Farrar, J. C. M. 2001. Lean austenitic Type 16.8.2 stainless steel weld metal, Stainless Steel World 2001 Conference Proceedings, paper P0114, KCI Publishing, Zutphen, The Netherlands. 2. Klueh, R. L., and Edmonds, D. P. 1986. Chemical composition effects on the creep of Type 316 and 16-8-2 stainless steel weld metal. Welding Journal 65(6): 156-s to 162-s. DAMIAN J. KOTECKI is president, Damian Kotecki Welding Consultants, Inc. He is treasurer of the IIW and a member of the A5D Subcommittee on Stainless Steel Filler Metals, D1K Subcommittee on Stainless Steel Structural Welding; and WRC Subcommittee on Welding Stainless Steels and Nickel-Base Alloys. He is a past chair of the A5 Committee on Filler Metals and Allied Materials, and served as AWS president (2005–2006). Send questions to damian@ damiankotecki.com, or Damian Kotecki, c/o Welding Journal Dept., 550 NW LeJeune Rd., Miami, FL 33126.

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WELDING JOURNAL

15

Friends and Colleagues:

I want to encourage you to submit nomination packages for those individuals whom you feel have a history of accomplishments and contributions to our profession consistent with the standards set by the existing Fellows. In particular, I would make a special request that you look to the most senior members of your Section or District in considering members for nomination. In many cases, the colleagues and peers of these individuals who are the most familiar with their contributions, and who would normally nominate the candidate, are no longer with us. I want to be sure that we take the extra effort required to make sure that those truly worthy are not overlooked because no obvious individual was available to start the nomination process. For specifics on the nomination requirements, please contact Wendy Sue Reeve at AWS headquarters in Miami, or simply follow the instructions on the Fellow nomination form in this issue of the Welding Journal. Please remember, we all benefit in the honoring of those who have made major contributions to our chosen profession and livelihood. The deadline for submission is July 1, 2012. The Committee looks forward to receiving numerous Fellow nominations for 2013 consideration.

Sincerely, Thomas M. Mustaleski Chair, AWS Fellows Selection Committee

Fellow Description DEFINITION AND HISTORY The American Welding Society, in 1990, established the honor of Fellow of the Society to recognize members for distinguished contributions to the field of welding science and technology, and for promoting and sustaining the professional stature of the field. Election as a Fellow of the Society is based on the outstanding accomplishments and technical impact of the individual. Such accomplishments will have advanced the science, technology and application of welding, as evidenced by: ∗ Sustained service and performance in the advancement of welding science and technology ∗ Publication of papers, articles and books which enhance knowledge of welding ∗ Innovative development of welding technology ∗ Society and chapter contributions ∗ Professional recognition RULES 1. 2. 3. 4. 5. 6. 7.

Candidates shall have 10 years of membership in AWS Candidates shall be nominated by any five members of the Society Nominations shall be submitted on the official form available from AWS Headquarters Nominations must be submitted to AWS Headquarters no later than July 1 of the year prior to that in which the award is to be presented Nominations will remain valid for three years All information on nominees will be held in strict confidence No more than two posthumous Fellows may be elected each year

NUMBER OF FELLOWS Maximum of 10 Fellows selected each year.

AWS Fellow Application Guidelines Nomination packages for AWS Fellow should clearly demonstrate the candidates outstanding contributions to the advancement of welding science and technology. In order for the Fellows Selection Committee to fairly assess the candidates qualifications, the nomination package must list and clearly describe the candidates specific technical accomplishments, how they contributed to the advancement of welding technology, and that these contributions were sustained. Essential in demonstrating the candidates impact are the following (in approximate order of importance). 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Description of significant technical advancements. This should be a brief summary of the candidates most significant contributions to the advancement of welding science and technology. Publications of books, papers, articles or other significant scholarly works that demonstrate the contributions cited in (1). Where possible, papers and articles should be designated as to whether they were published in peer-reviewed journals. Inventions and patents. Professional recognition including awards and honors from AWS and other professional societies. Meaningful participation in technical committees. Indicate the number of years served on these committees and any leadership roles (chair, vice-chair, subcommittee responsibilities, etc.). Contributions to handbooks and standards. Presentations made at technical conferences and section meetings. Consultancy — particularly as it impacts technology advancement. Leadership at the technical society or corporate level, particularly as it impacts advancement of welding technology. Participation on organizing committees for technical programming. Advocacy — support of the society and its technical advancement through institutional, political or other means.

Note: Application packages that do not support the candidate using the metrics listed above will have a very low probability of success. Supporting Letters Letters of support from individuals knowledgeable of the candidate and his/her contributions are encouraged. These letters should address the metrics listed above and provide personal insight into the contributions and stature of the candidate. Letters of support that simply endorse the candidate will have little impact on the selection process. Return completed Fellow nomination package to: Wendy S. Reeve American Welding Society Senior Manager Award Programs and Administrative Support 550 N.W. LeJeune Road Miami, FL 33126 Telephone: 800-443-9353, extension 293 SUBMISSION DEADLINE: July 1, 2012

CLASS OF 2013

(please type or print in black ink)

FELLOW NOMINATION FORM DATE_________________NAME OF CANDIDATE________________________________________________________________________ AWS MEMBER NO.___________________________YEARS OF AWS MEMBERSHIP____________________________________________ HOME ADDRESS____________________________________________________________________________________________________ CITY_______________________________________________STATE________ZIP CODE__________PHONE________________________ PRESENT COMPANY/INSTITUTION AFFILIATION_______________________________________________________________________ TITLE/POSITION____________________________________________________________________________________________________ BUSINESS ADDRESS________________________________________________________________________________________________ CITY______________________________________________STATE________ZIP CODE__________PHONE_________________________ ACADEMIC BACKGROUND, AS APPLICABLE: INSTITUTION______________________________________________________________________________________________________ MAJOR & MINOR__________________________________________________________________________________________________ DEGREES OR CERTIFICATES/YEAR____________________________________________________________________________________ LICENSED PROFESSIONAL ENGINEER: YES_________NO__________ STATE______________________________________________ SIGNIFICANT WORK EXPERIENCE: COMPANY/CITY/STATE_____________________________________________________________________________________________ POSITION____________________________________________________________________________YEARS_______________________ COMPANY/CITY/STATE_____________________________________________________________________________________________ POSITION____________________________________________________________________________YEARS_______________________ SUMMARIZE MAJOR CONTRIBUTIONS IN THESE POSITIONS: __________________________________________________________________________________________________________________ __________________________________________________________________________________________________________________ __________________________________________________________________________________________________________________ IT IS MANDATORY THAT A CITATION (50 TO 100 WORDS, USE SEPARATE SHEET) INDICATING WHY THE NOMINEE SHOULD BE SELECTED AS AN AWS FELLOW ACCOMPANY NOMINATION PACKET. IF NOMINEE IS SELECTED, THIS STATEMENT MAY BE INCORPORATED WITHIN THE CITATION CERTIFICATE. SEE GUIDELINES ON REVERSE SIDE SUBMITTED BY: PROPOSER_______________________________________________AWS Member No.___________________ Print Name___________________________________ The Proposer will serve as the contact if the Selection Committee requires further information. Signatures on this nominating form, or supporting letters from each nominator, are required from four AWS members in addition to the Proposer. Signatures may be acquired by photocopying the original and transmitting to each nominating member. Once the signatures are secured, the total package should be submitted. NOMINATING MEMBER:___________________________________NOMINATING MEMBER:___________________________________ Print Name___________________________________ Print Name___________________________________ AWS Member No.______________ AWS Member No.______________ NOMINATING MEMBER:___________________________________NOMINATING MEMBER:___________________________________ Print Name___________________________________ Print Name___________________________________ AWS Member No.______________ AWS Member No.______________

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RWMA Q&A Q: What is the process used to determine if a sheet metal spot welding schedule is suitable for the application? We have been utilizing the schedules the integrator recommended when we purchased the tooling, but we want to improve them, if possible. A: This question reminds us of the fact that no matter how much research we do, and despite all of the advances in the resistance welding industry (and there have been many), at some point we have to actually get down to business and make a weld. To accomplish this, we must undertake a good fundamental review of the process coupled with a thorough knowledge of the standard we are evaluating the welding against. Please note that the newer adaptive weld controls may require a different approach, but this is a subject for another time. Before we go any further, it is important to understand what a resistance spot welding schedule is. Specifically, it is the recipe used to create a weld and should contain all of the required elements needed to replicate the condition. These most likely include weld force in units of

BY DONALD F. MAATZ JR.

pounds-force (lbf) or kilo-Newton (kN), secondary weld current (either AC or DC) expressed as kilo-Amps (kA), and weld time in either milliseconds (ms) or cycles (c), based on 50 or 60 Hertz (Hz) AC power. The weld time callout should also specify the pulsing and cool time methodologies, if required. Other elements potentially included as part of the schedule are squeeze time, hold time, and in rare instances, the need for a pre/post heat treatment (quench and temper) or the up/down sloping of current. Additionally, the electrode geometry should be specified, including contact face diameter and perhaps the material composition (or class) of copper. Last, but most certainly not least, the values for the above elements are typically unique for a specific range of substrate thicknesses so it is common to see the schedule list them in a table. Resistance spot welding of sheet metal is a mature process with a great deal of research and history associated with it. The end result of much of this research was creation of established and welldocumented welding schedules for vari-

ous sheet metal and electrode configurations, schedules that have been refined over time. These spot welding schedules are beneficial for equipment sizing and serve as a starting point as the initial tooling launch and ramp-up process seeks to establish a consistent weld. One of these schedules (and there are many to choose from) was most likely the source of the integrator’s recommendation (Refs. 1, 2). But to help answer your question, it would be wise for us to keep in mind that any discussion regarding weld schedule development cannot take place unless the following items are understood: • The quality requirements are known and rational for the application. This is typically not an issue, especially since so many industry-recognized standards and reference guides, such as AWS D8.1, AWS C1.1, AWS D17.2, and the RWMA Resistance Welding Manual, are available. That being said, it is still possible to encounter a situation where rational thought and good engineering seem to be missing, so it pays to do your own homework. • The welding characteristics of the material are known. This item relates directly to which weld schedule methodology should be employed for the application. An example of the important characteristics that can drive the need for a unique schedule includes substrate coating, strength, and gauge. Additional items to consider are the number of faying surfaces to be joined and the ratio of the gauges being assembled. • The tooling, including the electrodes, is capable of supporting the needed force, current, and time, and at the desired rate. This item should almost be selfevident, but, just as with the quality requirements, it pays to do your homework. A lack of oversight in this area may result in the unfortunate discovery that an excellent weld may be achieved at 1400 lbf, but the weld gun is only capable of 1000 lbf. The Weld Lobe One way to express the robustness of a particular resistance spot welding application is to determine its lobe — Fig. 1. A weld lobe is a means of graphically expressing the numerous combinations of weld current and weld time that produce satisfactory welds for a specific set of conditions (weld force, electrode cap configuration, metal stackup, etc.). The lobe (sometimes called a window) is created by plotting the values of weld current vs. weld

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20

MARCH 2012

time that correspond to a particular measurable characteristic, most typically weld size. The left boundary of the lobe curve displays the combinations of weld current and weld time that produce a weld that meets the minimum acceptable quality requirements. The combinations of weld current and weld time to the left of the curve may still produce welds, but they will generally be of a less-than-desired quality as measured against a particular characteristic. The right boundary of the lobe displays the combinations of weld current and time that correspond to substrate expulsion or flashing. However, welds produced with parameters to the right of this curve may still meet engineering intent. The distance between these two boundaries at a given weld time is referred to as the current range. A wide current range is one indication of process robustness. As such, the stackup in question would be tolerant of changes in the manufacturing process and welding equipment resulting from normal process variation and equipment degradation. Conversely, a narrow current range is indicative of a process that is far less tolerant of typical manufacturing process variations. Such processes are most likely “fussy” and seem to demand much more than their fair share of attention. There are many other characteristics and factors related to evaluating and utilizing a lobe. A few examples are highlighted below: • The lobe is actually a single slice of a three-dimensional object. For example, if the third weld schedule variable of weld force is taken into account, it would be possible to construct a graphical representation of the lobe in three dimensions. For practical reasons, this is not typically needed (although it has been done) as adjustments to the appropriate weld force contribute little to a change in overall heat input when compared to alterations of weld time, and especially, weld current. • The shape of the lobe can reveal if the stackup responds to changes in weld time. The lobe in Fig. 1 is similar to a parallelogram. As such, it almost does not matter which of the tested weld times is selected as the final schedule. But what does it mean if the lobe is wider at the top and narrower at the bottom, much like an ice-cream cone? It may indicate that the lower weld times may not be able to produce an acceptable weld before the onset of expulsion and that operating at those levels would be, at best, ill advised. • A narrow overall width to the lobe may indicate that other factors need to be evaluated and modified so that the process window can be opened. As the lobe only captures changes to current and time, other aspects of the welding process such as electrode geometry and weld time

Fig. 1 — A resistance spot weld lobe. methodology (single vs. poly pulse, etc.) are common candidates for review and alteration before another attempt to determine the weld window. • As a rough rule of thumb, the minimum desired weld range, dependent on material and process, is 10–15% of the operating current to achieve a satisfactory weld. The weld time should be as low as

practical to achieve the desired range but not so low as to contribute to process instability. Additionally, the operating current should be slightly less than the midpoint of the range, again dependent on material and process. This takes advantage of the repeatability typically associated with producing acceptable welds at the lower end of the range and minimizes

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WELDING JOURNAL

21

the potential for spurious expulsion associated with higher current values. As your question alludes to the fact the process is presently producing welds of acceptable quality, how does the concept of a weld lobe apply to your situation? The answer to that question would be to determine where your process actually is in the lobe. This is not something that should be undertaken lightly, but, with care, you might be able to open the window under which acceptable welds can be produced and potentially discover how close to the edge of the lobe you actually are. A possible methodology would be to make small weld schedule changes of either weld time or weld current to a part that is going to be subjected to an off-line destructive evaluation. These small changes, if made at approximately the same time in the electrode life cycle, would be the source of the values used to construct your lobe. Once the welds are evaluated and compared to your particular measurable characteristic, the actual process window can be constructed. As previously mentioned, caution should be exercised as you make your changes. However, if you keep a few guidelines in mind, the process should go smoothly. • Any final schedule changes will need validation throughout the entire electrode life cycle.

• Make weld time changes in no more than 5% increments, if possible. • Maintain the same weld time methodology with all changes. • Make changes to the value of secondary weld current of no more than 2%, if possible. • Do not change weld force unless you have reason to believe it is too low, then reestablish the proper weld time and/or weld current. My suggestion is not to attempt to map the entire lobe, but rather to get a feel for the effect of different changes on your process. If you are able to determine that you have a robust process, it will give you a degree of confidence in the product you are producing. On the other hand, if you discover your process is not as robust as desired, you can begin a deeper evaluation into how to improve it. So, just as you need and expect your car to start each morning, you need and expect your tooling to be capable of producing a quality weld. A robust weld schedule is an excellent first step.◆ Acknowledgment I would like to thank Tom Morrissett, former AWS D8 chairman, for his invaluable perspective on weld lobe development.

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MARCH 2012

References 1. Resistance Welding Manual, revised 4th Edition. 2003. Miami, Fla.: American Welding Society. 2. AWS C1.1:2000 (R2006), AWS C1.1:2000, Recommended Practices for Resistance Welding. Miami, Fla.: American Welding Society.

DONALD F. MAATZ JR. is a laboratory manager, RoMan Engineering Services. He is chair of the AWS Detroit Section, serves on the D8 and D8D Automotive Welding committees, is vice chairman of the Certified Resistance Welding Technician working group and of the RWMA Technical committee. He is a graduate of The Ohio State University with a BS in Welding Engineering. This article would not have been possible were it not for the assistance from members of the RoMan team. Send your comments/questions to Don at dmaatz@ro maneng.com, or to Don Maatz, c/o Welding Journal, 550 NW LeJeune Rd., Miami, FL 33126.

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POINT OF VIEW

BY DENNIS CROCKETT

The Case for AWS Specifications For many years, the American Welding Society (AWS) has issued specifications for the classification of welding filler metals and allied materials. As stated in each specification, “AWS American National Standards are developed through a consensus standards development process that brings together volunteers representing various viewpoints and interests to achieve consensus.” The issuance and maintenance of these documents is the responsibility of the AWS A5 Committee on Filler Metals and Allied Materials and its 22 working subcommittees. In recent years, the American Welding Society has worked in cooperation with the International Organization for Standardization (ISO) to develop international ISO standards. Some ISO specifications are very close to the corresponding AWS specifications. For example, the newly issued AWS A5.32M/A5.32:2011 (ISO 14175:2008 MOD), Welding Consumables — Gases and Mixtures for Fusion Welding and Allied Processes, is a modified adoption of the ISO 14175 specification. Now one might conclude that the logical end game of all this effort should be the development of a set of international ISO standards that eventually would supplant the AWS standards completely. It may be logical but would it be smart? This writer thinks not and would make the following case for AWS specifications: 1. AWS A5 subcommittees can work to expedite provisions for new electrode types, emerging technologies, enhanced weld deposit compositions, updated qualification requirements, etc., to better address the needs of U.S. manufacturers and markets. Examples would be the “D” op-

tional, supplemental designator (to indicate conformance to seismic requirements) and the “Q” optional, supplemental designator (to indicate conformance to U.S. military requirements) that were incorporated into the AWS A5.20 flux cored specification. More recently, the AWS A5M subcommittee finalized a new specification, AWS A5.36/A5.36M, Specification for Carbon and Low-Alloy Steel Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding, in which provisions were made for electrode types intended for use with modified waveforms. See page 51 of this issue of Welding Journal for more information on this specification. It is not realistic to expect that the priorities of an international code body will always align with issues related to U.S. markets or that any action will be taken. In addition, the structure and membership of an international code body virtually precludes the fast tracking of document revisions. 2. AWS subcommittees have the ability to take a leading role in eliminating obsolete, unnecessary, and expensive test requirements. The AWS A5M subcommittee did this when it eliminated the fillet weld test as a classification requirement for flux cored electrodes in the new AWS A5.36/A5.36M specification. The AWS subcommittees can also add or modify testing requirements to their documents to ensure that the test procedures are consistent with the welding procedures the manufacturer recommends. This was done when the AWS A5M subcommittee added procedure controls in AWS A5.20/A5.20M for the hydrogen

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testing of flux cored electrodes based upon the manufacturer’s published procedure ranges. The AWS A5B submerged arc subcommittee also took the initiative when it added a two-run welding classification procedure for submerged arc welding. This was done to better reflect the mechanical property results that can be expected on limited-pass applications such as the two-run technique used in the manufacture of line pipe. 3. Manufacturers using AWS-classified products are familiar with the AWS classifications and have them written into their Welding Procedure Specifications and Procedure Qualification Records. We could expect serious objections from endusers over the cost involved in converting from AWS to ISO-only classified products. The AWS A5M subcommittee faced this same type of issue when developing the new AWS A5.36/A5.36M document. There was tremendous resistance to completely replace the fixed classification system and designations (specified in AWS A5.18/A5.18M, A5.20/A5.20M, A5.28/ A5.28M, and A5.29/A5.29M) with a new open classification system having new designations. For that reason, a number of widely used and accepted electrode types were “grandfathered” into the AWS A5.36/A5.36M specification with their existing classification designations and classification requirements. 4. Welding consumables classified to AWS specifications may also be classified to ISO specifications, if required. One does not necessarily preclude the other. 5. The work done by the AWS A5 Committee and subcommittees has value beyond the specifications they generate. AWS committee work provides a forum for manufacturers (who in many cases are direct competitors), end-users and interested parties to work together to the benefit of their industry. The younger members gain valuable experience through their participation and interaction. The older members provide years of experience, insight, and a historical perspective. All of this serves our industry and our markets.◆

DENNIS CROCKETT ([email protected]) is chair, AWS A5M Subcommittee on Carbon and Low-Alloy Steel Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding.

POLIFAN®-CURVE Gives You A Big Edge on Fillet Weld Finishing PERFECT CIRCLE

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PRODUCT & PRINT SPOTLIGHT GMA, SMA, and GTA Welding Machine Suited for Do-It-Yourselfers The Fabricator® 181i, the first in a series of 3-in-1 multiprocess, integrated portable welding systems designed to handle GMA, SMA, and GTA applications, delivers up to 180 A of output power. Weighing less than 33 lb, the compact system enables the ability to go from job to job as easily as users can go from GMA to SMA to GTA welding. It is suited for farm and ranch use along with other applications such as for do-it-yourselfers, automotive, light fabrication, hobbyists, maintenance, repair, and educational training. The product’s standard features include a detailed weld setup guide for good welding performance over a range of materials and shielding gases; digital meters with preview; infinitely variable voltage control; and metal feed plate with quick-change drive rolls and a receptacle for connecting remote control devices/spool gun. The system is made complete with Tweco® and Victor® accessories. Thermal Arc® www.thermalarc.com (800) 426-1888

Wire Gives High Deposition Rates for Shipbuilding

mill scale, and primer. It conforms to AWS A5.20/A5.20M:2005, Carbon Steel Electrodes for Flux Cored Arc Welding, E71T1C-H8 and E71T-9C-H8. The wire is offered in 0.045, 0.052, and 1⁄16 in. wire diameters wound on 15-lb plastic spools, 33-lb fiber spools, and 50-lb coils. The Lincoln Electric Co. www.lincolnelectric.com (888) 355-3213

Welding Carriage Useful for Building Ships, Trailers

UltraCore® HD-C, a mild-steel gas shielded flux cored wire, is an option for out-of-position welding requirements with 100% CO2 in the shipbuilding industry and other fabrication applications. Designed to provide high deposition rates and a flat bead appearance in all positions, it delivers good arc performance and fastfreezing slag with a low fume-generation rate. The wire has a wide operating range and is able to reach deposition rates of up to 10 lb/h, even in out-of-position applications. Also, it exhibits low spatter levels and is formulated to weld over light rust, 26

MARCH 2012

The Wel Twin portable welding carriage, tested in shipyards worldwide, carries two torches. The heavy-duty machine is designed to weld on both sides of a stiffener rib or I-beam up to 24 in. tall. Common uses are for ship and trailer building along with custom I-beam construction. The unit is magnetically attached from both sides of the plate by a main and sub carriage. An interface is included to send signals to both wire feeders when welding is to begin. Semiautomation improves quality, production times, and reduces welder fatigue. The machine is driven and held on a vertical plate gripped by the main and sub carriage to maintain consistent

welds. The company can provide information on running multiple carriages at once to provide a flexible panel line as well. Koike Aronson/Ransome, Inc. www.koike.com (800) 252-5232

Brochure Pictures Industrial Hydraulics

      
Wherever and whatever you need to cut or gouge — power through more work faster, with the full line of versatile Duramax™ torches for Powermax® systems.

The 28-page, full-color Intelligent Hydraulics in New Dimensions brochure discusses the company’s manufacturing facilities with well-illustrated discussions on its product lines. Featured are general descriptions of proportional valves and electronics, pumps, motors, accumulators, standard valves, manifolds, filters, power units, piping systems, and its engineering services. Sections are dedicated to the automotive, civil engineering, entertainment, heavy industry, defense systems, marine and offshore, mining, plastics, power-generation, pulp and paper, and wind-energy industries. Bosch Rexroth www.boschrexroth-us.com (610) 694-8300

Oxygen Indicator Includes PPM Sensor For a closer look, visit www.hypertherm.com/duramax

15° Handheld

75° Handheld The InterPurge Model 772 oxygen indicator measures rest oxygen levels down to 1 part/million (ppm) volume. The ceramic sensor, which is nondepleting, is designed for job site as well as clean room work for many years before replacement. The model also incorporates a heavy-duty pump, and the bright LED display has a measuring range of 1–999 ppm. Intercon Enterprises, Inc.

Full-length machine

Mini machine

MANUAL PLASMA | MECHANIZED PLASMA | LASER | AUTOMATION | CONSUMABLES | SOFTWARE

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Cyclone Spark Arrester Installs with Duct Clamps

The SparkShield is a compact, in-line spark arrester that requires little to no floor space. The patent-pending design ensures almost 100% efficiency in the removal of sparks and other potential hazards that may cause a fire. The product not only protects welding fume extraction systems against sparks, it also increases the lifespan of filter cartridges. Inspection hatches can be placed around it, which make looking inside the ductwork possible to check whether cleaning is necessary. Two duct clamps make it easy to install, dismantle, service, and maintain. Plymovent Corp. www.plymovent.com (800) 644-0911 For info go to www.aws.org/ad-index

A QUICK C , EASY, SAFE CL LA AMP M FOR OR HOLD L ING NG PIPE IN VE EE HEA AD JACK C STAND N S

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Rugged steel frame for years of use Perfect for securing Pe pipe layout work

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CAUTION: Hold-E is a clamping device and should not be used for threading or lifting.

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Grips 3/4" - 6" pipe (20 - 152mm) or 1" - 6-1/2" tubing (25 - 165mm)

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SUMNER M MANUFACTURING ANUFACTURING FA COMPANY, Y,, INC. INC

Wireless Crane Scale Keeps Users Far from Load

trial lifting magnets and how to use them to pile, unpile, lift, and move steel plates and shapes. Featured are the SafeHold® permanent lifting magnet models and the complete line of electric lift magnets. Detailed are permanent magnets with lifting capacities up to 10,000 lb and electric lift magnets up to 59,000 lb, with line drawings and specifications for each magnet plus photos that show the type of industrial applications most suited for each model. A PDF edition may be downloaded from www.eriez.com/Products/SafeholdPermanentLiftingMagnets. A hard copy may be ordered by e-mailing the request to [email protected] or online at the Web site shown below. Request brochure MB-2300. Eriez® www.eriez.com (888) 300-3743

The Alliance/CAS Caston II crane scale, with a heavy-duty swivel hook, is designed for weighing products from an overhead hoist or crane and features a standard hand-held wireless remote control, on/off, zero and tare functions, and auto span calibration with auto zero tracking. Allowing users to stand clear from the load, the product has a 1.2-in. LED display. Equipped with a rechargeable battery pack, the scale includes a spare battery pack and charger. Weighing 37.5 lb, it is offered in three capacities — 1000 × 0.5 lb, 2000 × 1 lb, and 5000 × 2 lb — and operates on 6 VDC power.

Orbital Weld Heads Utilize Digital Technology The Model 860 fusion welds tube from 2 to 6 in. The company recently introduced the 800 Series, a line of enclosed autogenous orbital weld heads that utilize digital technology. The product is a compact and lightweight 6-in. head. Just 0.75 in. of straight length is required, tungsten

to collet face. It is 1.7 in. wide, allowing use for tight clearance applications welding fitting-to-fitting or fitting-to-valve. Magnatech LLC www.magnatechllc.com (860) 653-2573

Dual Torch Hard Surfacing System Installs Quickly The company has redesigned its dual torch shredder disc rebuild system that re-

Alliance Scale, Inc. www.alliancescale.com (800) 343-6802

Use of Lifting Magnets Discussed in Literature

The 24-page Lifting Magnets Complete Line brochure discusses the various indusFor info go to www.aws.org/ad-index

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Digital System Measures Instantaneous Current

Manufacturin Manufacturing uring

Flux Cored Welding elding Wire W COBALT LT NICKEL HARDFACE E STAINLESS TAINLESS ALLOY Y STEEL EEL

duces installation time to 30 min or less. It can apply 50 lb of weld metal per hour and includes two weld carriages that support the weld arm and adjustable open arc torches, wire feeders, and 60-lb coils of wire. The carriage’s opening design allows the main beam and legs to be installed first and the carriages second. The controls have been consolidated into a single handheld pendant. With remote start/stop, the user can pause to inspect the work and begin again without worrying about “wire whiskers” because a built-in, melt-back circuit eliminates the welding wire sticking to the workpiece. The disc rebuild system is a match with Stoody® 110MC, a modified high-chromium manganesesteel metal cored wire.

Joulebox 2, a portable, digital system, is designed to measure instantaneous voltage, amperage, and power (J/s) in accordance with ASME IX, QW-409.1(c) where waveform-controlled welding power sources are in use. The unit can be used with any power source. Additionally, measurements are taken near the arc, so cables, torches, or other items that influence results are eliminated.

Mavrix Welding Automation, Inc.

Euroweld, Ltd.

www.mavrixweld.com (262) 679-3800

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TOOL STEEL STEE EEL WELDING AND POWER SOLUTIONS FOR SHIPYARDS

MAINTENANCE MAINTENAN CE FORGE ALLO ALLOYS OYS CUSTOM ALLOYS OYS COR-MET,, INC. COR-MET, 12500 Grand and River Rd. Brighton, MI 481 48116 116 800-848-2719 PH: 800 -848-27 719 810-227-9266 FAX: 810 FA -227-9266 www.cor-met.com www.cor ww -met.com t.com [email protected] sales@cor -met.co t.com For info go to www.aws.org/ad-index

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Welder Rentals Welder-Logistics Lease Programs Welding Equipment Fleet Management Inverter Welders and Paks Advanced Process Welders Wirefeeders Automatic Welding Tractors and Heads Multioperator DC Converters Induction Heating Equipment Welding Fume Extractors Positioners, Manipulators, Turning Rolls Power Generation and Distribution Stud Welders

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Industrial Products Catalog Updated

Viewable online, the company has released its updated full-color, 164-page product catalog combining its metal fabrication and industrial product lines, including more than 200 new items. Featured are ceramic grain trimmable flap discs, surface-conditioning belts, Diamond-X wheels, wire brush flap wheel drums, Quickie Cut cut-off wheels with 5⁄8to 11-in. hubs, and cylindrical grinding wheels. Visit the Web site shown to view the catalog, or request a hard copy from the contact information below. CGW-Camel Grinding Wheels www.cgwcamel.com (800) 447-4248

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Fig. 1 — The Eleftheria K at sea.

BY DAVID PHILLIPS ([email protected]) is with Group Communications, Hydrex, Clearwater, Fla.

Undertaking a Complex Underwater Repair A damaged freighter needed repairs to stop a leak, prevent buckling, and keep cracks from spreading so the ship could sail to where she could unload

he Eleftheria K (Fig. 1), a Capesizeclass bulk carrier, ran aground at the mouth of the Suez Canal in July 2011. European Navigation, Inc., Piraeus, Greece, operates the ship, which was built in Japan in 1985. The Eleftheria K is 297 m long overall, 50 m in the beam, 214,263 metric tons DWT (dry weight), with a 26.7-m depth, 19.8-m draught, and a displacement of 240,311 tons.

T

The Damage When she ran aground, the Eleftheria K had on board a full cargo of iron ore concentrate, totaling 212,297.75 metric tons, which had been loaded at the ports of Odessa and Yushny in the Ukraine for discharging at Rizhao and Qingdao, China. The starboard bilge strake was grounded at the level of double-bottom

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ballast tanks (DBBTs) 1, 2, and 3. The damage was extensive, covering about 85 m along the hull. The grounding caused severe indentation of the bilge strake, opening seven holes and cracks along the damaged area resulting in the flooding of ballast tanks 1, 2, and 3 — Fig. 2. A local diving company in Egypt carried out temporary repairs using doubler plates and putty from the outside and cement boxes on the inside — Fig. 3. The ship then resumed its voyage to China. However, one week after sailing from Suez, the ballast tanks flooded again and a vertical crack developed on the starboard vertical side shell plating, on the aft part of the area damaged by the grounding and just forward of the bulkhead between DBBTs 2 and 3, and cargo holds 3 and 4 — Fig. 4. The approximately 1300-mm-long

crack had an average uneven gap of 100–200 mm. Had it propagated upward, the crack would have caused cargo holds 3 and 4 to flood, which could have been

catastrophic for the vessel and her cargo. The most difficult part of the underwater repairs was covering this crack/fracture for it to become watertight while at the same time maintaining local and longitudinal strength to a level higher than the minimum required by the rules. Underwater repairs and reinforcements had to be carried out at a depth of approximately 19 m with the ballast tank flooded, meaning equal pressure from inside and outside. Repair procedures and welding quality had to be at maximum in order to hold firm while deballasting the ballast tank so the shell plate could cope with the resulting hydrostatic pressure from the outside. To effect these repairs, the ship had to be diverted to an anchorage at Fujairah, United Arab Emirates.

Inspection S. Georgiou, technical manager of European Navigation, Inc., called in Hydrex, an international underwater repair and maintenance company based in Antwerp, Belgium. The Hydrex inspection revealed a new vertical crack directly on the bulkhead between ballast tanks 2 and 3. Georgiou said he decided to call in Hydrex for the repairs because “due to the extent and the severity of the damage, the job was considered very difficult; therefore, we decided a specialized company such as Hydrex, with a successful record, well organized, safety oriented, and experienced in underwater welding jobs, should be arranged. Furthermore, any other option to discharge her cargo ashore and/or transfer the cargo to another ship was impossible due to the ship’s size, her deep draft, quantity of cargo on board, no availability of suitable port/berth facilities for a vessel of that size in the area, and no availability of shore floating cranes.” Toon Joos, an experienced senior diver/welder/technician with Hydrex, flew to Dubai to conduct a detailed inspection at Fujairah 20 miles off the coast. His report and some of the photos from that inspection follow.

Fig. 3 — (Top) The buckled hull and the previous attempt at repairs. Fig. 4 — (Bottom) Close-up showing the severity of the long, vertical crack discovered in the hull.

Fig. 2 — The ship at anchor near Fujairah, UAE. The ship has a severe list to starboard due to the leaks and flooding of the ballast tanks.

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Fig. 5 — Sketches of the damage and repair proposal: A — Transverse view of the side shell vertical fracture; B — repair proposal for the vertical fracture.

A

B

Fig. 6 — Exterior view of the side shell repair proposal for the vertical fracture.

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Fig. 7 — Sketches of the sequence (left to right) for fitting the repair.

“The damage starts approximately on frame number 315 and runs all the way to frame number 227, a total length of approximately 100 m with a height on the vertical side of approximately 6 m and a width under the flat bottom of approximately 3 m. All the plating is pushed inside heavily with several cracks that have been repaired by other diving companies by means of doublers and epoxy putty. Unfortunately, there are still leaks. We can’t determine the locations due to the previous repairs and because the tanks (numbers 1, 2, and 3) are flooded. Between tanks 2 and 3, I can see there is a crack 1300 × 10 mm just in front of the bulkhead. There is a repair done by (local company), but the shell plating is pushed inside due to the water pressure when the tank was pumped out.”

Planning the Repair Part of Joos’s report was a proposal for repair of the damage. The idea was to

make sufficient repairs for the vessel to sail to China to unload her freight. Then she could be drydocked and permanent repairs made. The main problem was to sufficiently reinforce the 1.3-m vertical crack to prevent the torsion of the ship while under way from expanding it and breaking the ship, and to make the hull watertight so that the ballast tanks could be pumped out. The first step of the proposal was to involve a naval architect so that the various drawings and calculations could be done and approved.

The Naval Architect Hydrex had recently worked successfully with Michalis Chourdakis of C. N. Zachopolous & Associates Ltd., marine surveyors and consultant engineers, Piraeus, Greece. The company recommended his services to Georgiou, who was in charge of the repair operation for European Navigation. Chourdakis is also a technical consultant with Tsavliris Salvage

Co., one of the world’s leading salvors. In this case, no salvage operation was required so Tsavliris was not involved, but Chourdakis explained that his work with Tsavliris has given him a great deal of experience with major repairs of this nature. Chourdakis and his colleague, P. Koutsourakis, a surveyor and specialist in 3D drawings and presentations, studied the results of the Hydrex inspection and the proposed repairs and worked out the engineering details. They came up with a new description of the damage, a plan for repairs, calculated the various strengths and thicknesses required, and produced a set of drawings.

Grounding Damage Following is the new damage description and temporary repairs proposal. The damage description is based on information received from the Hydrex diver on board at Fujairah on May 9, 2011. The report stated in part: “On the side

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Fig. 8 — (Top) Construction of the initial frame on the deck of the freighter. Fig. 9 — (Bottom left) The distorted shape of the hull was carefully measured in relation to the frame, with measurements taken every 5 cm, so the plates that would become the structure of the box could be accurately cut to fit. Fig. 10 — (Bottom right) The plates were lowered down the side of the ship so they could be fitted accurately to the damaged hull before being welded into a watertight box on deck.

shell plate starboard side and in the area of the double-bottom ballast tank No. 2 starboard found a vertical crack of approximate dimensions 1300 × 10 mm located between frames No. 228 and 229 and on the first plate after the bilge plate. Double-bottom ballast tank No. 2 starboard is flooded — Fig. 5.

Repairs Proposal The purpose of the repairs was to accomplish the following: • Stop the crack (avoid propagation). • Reinforce the damaged area. • Reinstate water tightness of doublebottom ballast tank No. 2. • Reinstate the continuity of the doublebottom side longitudinals. • Reinforce the cracked side shell plate to avoid movement. Following is the repair plan: • To stop the crack and avoid propaga36

MARCH 2012

tion, drill adequate crack-arrest holes on the shell plate at both ends of the crack — Fig. 6. • To reinforce the damaged area, fit four angle bars and weld them externally on the shell plate in line with the existing double-bottom tank’s side longitudinals covering two web frame spaces. • Extend the stiffening longitudinally from frame 225 to frame 231. • Fit same-size angle bars and weld them vertically and in line with frames 228 and 229. These would be extended one side longitudinal up and down from the crack’s ends — Fig. 6. • Form the web of the angle bars to exactly fit the hull’s actual shape. Three-dimensional fitting sketches show how the repair was planned to go forward — Fig. 7. Hydrex confirmed that the plan could be executed, and European Navigation accepted the proposals.

All calculations for the local and longitudinal strength of the vessel were submitted and approved by the vessel’s classification society, Nippon Kaiji Kyokai (Class NK), and H&M Underwriters’ surveyors. While the work was being conducted, a Class NK surveyor was on site to verify the repairs were carried out according to the approved drawings. Chourdakis noted that for the job to be successful, high-quality welding and precise premeasurements were required.

Making the Repairs Hydrex flew two experienced divers/ technicians, Cedric Wyckmans and Philip Martens, from Antwerp to Dubai to make preparations for the job, including securing a suitable workboat and other necessary equipment. A week later, Joos flew in with a team of four additional divers/ welders/technicians. Work began and con-

Fig. 11 — (Left) The 300 × 60 cm box fabricated on deck prior to being lowered into the water and welded to the hull. Fig. 12 — (Right) Close-up showing the box in position over the crack.

tinued intensively, day and night, for the next 5½ weeks. The first step was to take measurements for the frame that would be fabricated and then welded in place over the large vertical crack. The frame would form the structure of the cofferdam that would be used to make the crack watertight and would also be used as a frame of reference so that accurate measurements could then be made and plates cut and welded in place. Hydrex welders working with subcontractors on the deck of the Eleftheria K constructed the frame — Fig. 8. With the frame in place, measurements could then be taken so that the sides of the cofferdam could be cut to the shape of the badly buckled hull and then fitted — Fig. 9. Joos explained, “A good fitting makes it much easier to weld. Under the water, a gap of 1 cm is a lot harder to weld than a gap of 3 mm. If you go over 1 or 1.2 cm, then you have to build up. So about 1 cm is the limit. Some welders can handle a 1 cm gap. A good fit makes it much easier. If you have a zero gap, it saves hours and hours of welding time.” With the ship out of service until the repairs could be completed, the old adage, “time is money,” took on a whole new meaning. The plates were cut on deck, then lowered and tacked to the hull so they could be adjusted to ensure a close fit before

Fig. 13 — Strip welding the longitudinal stiffeners in place on the shell plate.

being welded to the box — Fig. 10. After the plates were fitted, the 300 × 60 cm box was constructed on deck — Fig. 11. This was done because surface welding is somewhat faster than underwater welding. The finished box was then lowered into the water and welded to the frame and the hull, inside and out, three passes throughout — Fig. 12. Once the box was in place, the stiffeners were ready to be welded onto the hull extending fore and aft from the cracked hull area. The stiffeners were fabricated on deck, then lowered into position and tack welded in place. They were then strip welded with a 15-cm strip every 15 cm, top and bottom of the stiffeners — Fig. 13. The next step was to close the coffer-

dam by welding a plate on top of the box that had already been welded to the hull and the frame. When the cofferdam was sealed, the crack was no longer open to the sea — Fig. 14. Joos recalled the problems encountered when ballast tanks 1, 2, and 3 were deballasted — Fig. 15. “When we started pumping, unfortunately some cracks broke. Nobody knew what was inside — how many longitudinals were still attached on the inside — so we put additional stiffeners and then tried to pump again. Again, we had a few minor cracks. Because the depth of the vessel was 24 meters on the bottom, there was a huge amount of pressure forcing inward. The full structure needed to resist the pressure. We had a few cracks again so we de-

Fig. 14 — Closing the cofferdam over the crack.

cided to stop and put in some additional stiffeners in more layers to get more strength on the welds. The third time we started deballasting everything went okay. There was no further leak.” Georgiou added, “Furthermore, during the course of repairs — due to failure of the reinforcements — the original repair plan had to be reviewed twice and extra stiffeners had to be fitted.” This proved the degree of difficulty of the job, according to Georgiou. Finally, just 27 days after work began, the repair was finished with all stiffeners and brackets in place and welded. Epoxy

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was applied to prevent the welds from rusting — Fig. 16. Another team worked on the inside after the crack was made watertight and the ballast tanks could be pumped out. It was with this repair fully completed with classification society approval that the ship was able to sail. External welding totaled approximately 500 m, an incredible amount of welding for the given timeframe, particularly when one considers that most of it was underwater and at considerable depth. Shielded metal arc welding was used throughout. Two welding machines

worked constantly, and there was a third on standby as a backup. The equipment is basically the same as is used above water except that a different electrode, suitable for underwater use, is employed. The underwater external repair was carried out by seven Hydrex welders working in shifts. The diving routine consisted of two hours under the water followed by a 21-min decompression stop at 3 m and then a 4-h interval before diving again in the afternoon, following the same routine. The divers dove once or twice daily following the same routine, with two divers in the water at the same time. All the

B

A

Fig. 15 — A — Additional reinforcement was added to the repairs to ensure the welds would hold up when the ballast tanks were emptied; B — a closeup of the reinforcement.

divers used nitrox, a 40% oxygen/60% nitrogen mixture. At the beginning, the divers worked at a depth of 20 to 21 m. When the ballast tanks were emptied and the ship came up straight, recovering from its list, they were working at 17 m. Georgiou, who chose the repair company and the naval architects, was very satisfied with the work and the results. “We had very good cooperation during the entire period of repairs,” he said of the teamwork between European Navigation, the naval architect, and Hydrex. “The repair was successful, allowing the vessel to sail to China; therefore, the quality of the job was good. The job completed in about 27 days, which was very close to quoted time (24 days), but it should be considered that additional reinforcement had to be carried out, therefore the speed was also satisfactory.”

ship is 27 years old, she has several years of service life ahead. “The vessel arrived at its port of destination for discharging doing good speed despite encountering heavy weather and without any damage to the repairs carried out or any other damage,” Chourdakis said. Georgiou said, “Upon completion of underwater repairs, some additional repairs/reinforcements carried out inside the ballast tanks (according to the request of naval architect) and the vessel was inspected by Class. Everything was found okay and she resumed her voyage to China to discharge her cargo. The ship arrived

in China after about 30 days voyage, without any problem or water ingress in the ballast tanks during the voyage, and discharged/delivered all her cargo safely, at the ports of Rizhao and Qingdao. The provisional repairs carried out by Hydrex at Khorfakkan anchorage enabled the vessel to perform the voyage to her destination safely.” The repairs to the Eleftheria K can be considered a major accomplishment in the field of underwater ship repair and a testimony to the skill and teamwork of the ship operator, the naval architect, and the divers/technicians who carried it off successfully.◆

Conclusion The purpose of this repair to the Eleftheria K was to stop the leak, prevent buckling, and stop the cracks from spreading so the ship could sail to where she could discharge her full load and then go to drydock for permanent hull repair. The repair was warranted because although the Fig. 16 — The finished repair. The welds were protected with epoxy to prevent corrosion.

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FABTECH Comes to Canada

Discover innovative products and solutions from leading suppliers, and exchange ideas and find answers from industry experts at the inaugural FABTECH Canada

A view of the Toronto skyline showing the landmark CN Tower. (Photo courtesy of Tourism Toronto.)

The land of maple leaves will host the inaugural FABTECH Canada exhibition March 20–22 at the Toronto Congress Centre. The center is located in the heart of Canada’s engineering and technology region, and will be Canada’s only exclusive welding, fabricating, and metalforming event. Sponsors of the event are the American Welding Society, Society of Manufacturing Engineers, and Fabricators & Manufacturers Association. Following are just some of the reasons why the show partners decided to establish FABTECH Canada and locate it in Ontario. • Canada has an estimated 1.5 million manufacturing professionals in industries ranging from automotive and energy to transportation and construction. • Canada has a large export industry. Eighty percent of Ontario’s exports are to the United States. • Canada is the third largest exporter of automotive products after Japan and the United States, accounting for 16.7% of North America vehicle production. • There are 11,160 fabrication companies in Canada. • Welding represents about 75,000 jobs at the technician and welding operator 40

MARCH 2012

level in Canada. • Forty-five percent of all construction materials fabricated in Canada are made out of metal; capital construction indicates more than $100 billion of economic activity. When you attend FABTECH Canada, you’ll be able to see tools and technologies from hundreds of companies at one time and at one place; meet experts and your professional peers; and get the opportunity to attend expert-led educational sessions.

General Information Location Toronto Congress Centre 650 Dixon Rd., Toronto

Show Dates and Times Tuesday, March 20, 10 a.m. to 6 p.m. Wednesday, March 21, 10 a.m. to 6 p.m. Thursday, March 22, 10 a.m. to 4 p.m.

Registration Complimentary advanced registration is available until Monday, March 19. Reg-

istration after March 19 is $30 (tax included). Visitors must register to receive a show badge to attend the event. For more information on registration, conferences, and accommodations, go to www.fabtechcanada.com.

Featured Technologies Following are just some of the technologies that you’ll see first-hand on the show floor or that will be covered in the conference sessions: Arc Welding Assembly Bending and Forming Brazing and Soldering Coil Processing Finishing Fastening and Joining Forging Gases and Gas Equipment Hydroforming Inspection and Testing Joining Lasers Lubrication Material Handling

Maintenance and Repair Metal Suppliers Press Brakes Plate & Structural Fabricating Punching Resistance Welding Roll Forming Robotics Safety and Environmental Software Saws Stamping Stud Welding Tool and Die Tube and Pipe Thermal Spraying Tooling Welding Consumables Welding Machinery

Conferences Prices range from $175 member/$200 nonmember for one session to $555 member/$645 nonmember for the full conference (four to five sessions). Nonmembers who sign up for three or more conference sessions receive a full one-year membership to the sponsoring organization of their choice.◆

The Toronto harbourfront. Toronto and the province of Ontario form the center of Canada’s engineering and technology region. (Photo courtesy of Tourism Toronto.)

Conference at a Glance Wednesday, March 21 10:15 AM – 12:15 PM

Thursday, March 22

10:15 AM – 12:15 PM Fundamentals of Laser Welding

Essential Tips for Welding Aluminum

The Future of the Welding Industry’s Workforce

Refill Friction Stir Spot Welding Aluminum Filler Alloy Selections Aluminum Welding Machine Selection

Green Stud Welding Saves Energy and Labor Costs Utilizing Technology to Address the Need for a Manufacturing Workforce

Tuesday, March 20

Hot Wire Laser Cladding for Life Cycle Cost Reduction

Comparative Cutting: Advancements in Cutting Laser Cutting Considerations for First­Time Buyers Avancements in Plasma Cutting Process Op­ timization Resulting from Cut­to­Cut Cycle Time Reduction

1:15 PM – 3:15 PM Preventing Weld­Associated Cracking in Nickel­Based Alloys Lasers: General to Advanced Laser Cutting Considerations Laser Processing Technology Today NIR Laser Cutting Dynamics with High Beam Quality Fiber vs. CO2 Cutting

Tube & Pipe: Forming and Fabricating Tube & Pipe Tube and Pipe Mill Set Up Laser Tube Cutting

1:15 PM – 3:15 PM

10:15 AM – 12:15 PM

Brake & Punch: Fabricating Sheet Metal Press Brakes Press Brake Tooling Press Brake Troubleshooting

High­Power Laser Applications in Industry Roll Forming: General to Advanced Roll Forming Concepts Advanced Roll Forming of Steel Framing Components Moden Lubricants for Roll Form Processes

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BY GIRARD A. MIRGAIN ([email protected]) is global product line manager, Aluminum, ESAB AB, Rolla, Mo.

A Joint High-Speed Vessel being launched at the Austal yard in Mobile, Ala.

Welded Aluminum on Ships —

An Overview

The story of the use of welded aluminum on ships is ever evolving he news, in January, about cruise ship Costa Concordia suffering a long portside gash then tipping aground off the coast of Italy reminded the author of his 1976 line voyage from Sydney, through the Panama Canal, to Southampton aboard the SS America — Fig. 1. She was a typical ocean liner of the time with riveted steel keel, frame, and plates. Launched in 1939, America was built using construction methods not substantially different from those used for the Titanic some 30 years earlier (Table 1).

T

The Use of Aluminum in Shipbuilding The story of welded aluminum on ships begins with the design and construction of the SS United States — Figs. 2, 3. Conceived and designed by Fredric and William Gibbs as a 1000-ft express superliner, taking advantage of the technologies that had been rapidly evolving up to

and through WWII, SS United States was an avant garde vessel. In addition to meeting all the criteria to become a competitive commercial ocean liner, she had to be designed and built to rigid U.S. Navy standards in order to qualify for substantial U.S. government capital subsidies as an emergency auxiliary troop transporter. Among the additional criteria set out for this, she needed to be the following: • Fireproof. She would contain no wood except butcher block and the pianos. Aluminum was used extensively to replace most wooden items including furniture. • Convertible within 48 hours into a transporter for 15,000 troops. • A “Panamax” vessel (just narrow enough to transit the Panama Canal) with a 10,000 nautical mile cruising range at high speeds, and on a single bunker of fuel. • Robust in combat, capable of enduring a single bomb or torpedo hit and still be able to move out of harm’s way. She

Fig. 1 — The SS America in Papeete, French Polynesia, in 1976.

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Table 1 — Comparison of Three Ships Vessel Name

LOA (ft)

Knots

Passengers

Shipyard

Commissioned/Flag

Owner

Hull/Superstructure

SS America SS United States

636 990

22.5 32–38

2440(a) 1930

Newport News USA Newport News USA

1940/USA 1952/USA

All Riveted Steel Welded Steel/Welded Alum.

MV Costa Concordia

925

21–23

4300

Fincantieri Sestri Ponente

2006/Italy

United States Lines United States Lines Carnival Corp.(b)

Welded Steel/Welded Alum.

(a) Passenger numbers for SS America included large numbers of third-class “steerage” berths. (b) London and Miami; traded on New York and London stock exchanges.

would be extensively compartmentalized and have two separate and independent engine rooms. In describing the United States, her designer, William Francis Gibbs, said, “You can’t set her on fire, you can’t sink her, and you can’t catch her.” In an effort to conceal design secrets, her keel was laid at Newport News Shipyard directly on the floor of a graving dock so as not to be easily visible from a distance. As soon as the watertight hull construction was completed, the dry dock was flooded to further conceal her commercial secrets. Her construction required 1500 miles of welds. The United States had, for the first time, 2000 tons of welded aluminum in her superstructure; however, the superstructure was not all aluminum. The fore and aft framing and some of the plating were aluminum. This material all came

Fig. 2 — (Left) A 1952 Alcoa magazine ad for the SS United States (from Alcoa/AlcoTec photo archives). Fig. 3 — (Right) The 55-ft welded aluminum funnel of the SS United States in 1952 (from Alcoa/AlcoTec photo archives). Fig. 4 — (Bottom) The Aircomatic #1, 1948, the first manual GMAW wire feeder. It was designed specifically for welding aluminum. (From ESAB NA photo archives, compliments of Bob Bitzky.)

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from Alcoa, which was developing filler metals to weld such material. It is believed the filler metal used for this project was Alcoa XC56S, the great grandfather of AlcoTec Almigweld 5356. The Heliarc® process (gas tungsten arc welding) had been developed during WWII and was becoming commercially available at the end of the war. It was skill intensive, however, and slow. An entirely new welding process was conceived and developed to weld this comparatively massive aluminum SS United States superstructure. This process utilized inert gas shielding as with Heliarc® but instead of a tungsten electrode, it used a continuously fed welding wire as the process electrode. The first commercial name for this process was “Aircomatic” in 1948 — Fig. 4. Later, of course, it became known as metal inert gas welding (MIG), and now is known as gas metal arc welding

(GMAW) since it is far more extensively used now with active gas for welding, most commonly, steel. Technology is said to be autocatalytic. It is interesting to recall that the particular convergence of technologies called up for the SS United States project was also a catalyst for development of the manually operated, gas shielded continuous electric arc wire welding machines that dominate the world welding industry today. The SS United States dominated its realm for the remainder of the transAtlantic ocean liner era until the air travel industry displaced the line voyage market. Unfortunately, this early foray into GMAW of aluminum ship superstructures was not continued after SS United States was launched. It was fully ten years later, in 1962, before another ocean liner, the SS France, was built that incorporated an aluminum superstructure (1600 tons).

This gap is understandable since new concepts then needed to be developed in peripheral supporting industries and technologies: • Industrial gas companies needed to retool and develop appropriate “shielding” gases along with handling, distribution, and control methods to support the changing welding industry. In fact, industrial gas companies, with the most to gain, assumed a lead in developing ever-better welding equipment and some materials to capture the GMAW business. • In conjunction with a newly reconstituted Aluminum Association, a new, nationally agreed upon four-digit aluminum alloy numbering system was developed. This numbering system is now used nearly worldwide (Russia being a notable exception). • New application-appropriate aluminum base materials needed to be developed along with companion alloys to weld them. With a growing number of base metal combinations, research needed to be done for filler metals appropriate to many base metal combinations. • Aluminum welding wire showed marked improvements in quality and consistency in the late 1970s and early 1980s. In 1965, four years after the SS France was commissioned, the author crewed on Coast Guard Cutter Westwind, while in Bethelehem Steel Shipyard, Baltimore, Md., as she was fitted with an all-welded telescoping aluminum flight hangar for helicopters — Fig. 5. It was in 1967, 15 years after SS United States was placed in service, before the U.S. Coast Guard commissioned its first Hamilton class cutter incorporating an all-welded aluminum superstructure.

Activity in Australia

Fig. 5 — (Above) In 1965, the U.S. Coast Guard Cutter Westwind was fitted with a new aluminum helicopter hangar. Fig. 6 — (Left) Incat owner Robert Clifford poses with the Hales Trophy in 1990. Fig. 7 — (Bottom) The Incat yard utilizes a uniform technique for all its aluminum welding operations.

After U.S. Coast Guard military service and university studies, the author moved in 1974 to Australia where he spent the best part of 25 years in the welding industry. This article continues from that geographical perspective.

The Blue Riband and the Need for Speed From Ambrose Light, N.Y., to Bishop Rock, UK, was the measure for “the ship which shall, for the time being, have crossed the Atlantic ocean at the highest average speed.” For 38 years, from 1952 until 1990, the Hales Trophy and the right to fly the “Blue Riband,” belonged to the SS United States. The concept was that the aluminum superstructure reduced her displacement and increased her resistance-to-power ratio and, therefore, her speed. In June 1990, her record was finally beaten by an aluminum catamaran WELDING JOURNAL

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Fig. 8 — (Below top) Incat mills corner radii to avoid large-sized fillet welds. Fig. 9 — (Right) An example of tapering the thicker element of dissimilar thickness butt joints and use of a run-on tab. Fig. 10 — (Below bottom) A Panamax-width ship’s transom under construction.

ferry boat built in Hobart, Tasmania — Fig. 6. Since then, three vessels in succession, each built by Incat in Tasmania, have taken this trophy. Average crossing speed for the SS United States was 34.5 knots. The current record average speed for the latest Incat vessel is 41.3 knots. A shipping accident in 1975 was Incat’s genesis. Hobart, Tasmania, was cut in half when a freighter took out a bridge pier and section over the Durwent River. Robert Clifford, whose initial responding concept was better than his timing, began work building a ferry to replace the missing river crossing. The ferry was not completed before the bridge was repaired. This situation precipitated an alternative 46

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concept: to build and sell catamaran ferry boats to the world market. Hence, the name International Catamaran, which was subsequently shortened to Incat.

Some Incat Yard Concepts • Hiring carpenters and training them to weld aluminum. It was reasoned that, at least initially, in a relatively small city located on a remote timber industry island, it would be easier to find and train carpenters, who could already measure, mark, and cut, to weld aluminum than to find and retrain steel welders. An upside of this decision is that it was easier to effect a uniform welding technique

and methodology throughout the yard. • Holding welding operators to be accountable as their own first-quality managers. The cost to remove and repair a weld is far greater than correctly welding the first time. • Use of a single filler metal for all yard aluminum welding applications reduces inventory and shelf life, and eliminates risk of an incorrect filler metal being applied. • Demand standard welding preparation, including aggressive cleaning to bright bare metal. • Training and enforcing a uniform welding technique — Fig. 7. • Using only equipment that can deliver such welding technique. • Avoiding large-dimension fillet welds whenever possible. Instead milling corner radii adjacent to double-V butt joint welds — Fig. 8. • Using run-on and run-off tabs in critical applications — Fig. 9. • Tapering the thicker element of dissimilar thickness butt joints. • Develop and focus on a best-in-class design for the market and the real and intended capabilities of the yard, then build only that design vessel. • Build vessels on “spec.” The risks were high, mostly related to finance and inventory, but the potential gain was great. • Continuity of workforce and reduction of skills and training costs. • Direct application of lessons learned for continuous improvement. • Saving the one-time higher cost to build the first vessel in a series. • Reduce time from order receipt to delivery and payment. • Reduce lost orders due to lead time. • Justification to build single-vessel design-specific equipment and even buildings. • Building a wide (Panamax beam) 1000ft-long assembly building (Fig. 10) through which standard-width vessels can progress as they are being assembled (stern first to sea) with shop floor troughs for each hull that is flooded for float-out launches — Fig. 11. Incat is currently building an LNG-powered vessel for service between Argentina and Brazil — Fig. 12. In this market, LNG fuel is competitive with diesel, but the risks are much lower for a spill in a situation such as Costa Concordia finds itself.

The World Aluminum Shipbuilding Market Costa Concordia is a cruise ship owned and operated by Costa Cruises, Italy, which is in turn owned by Carnival Corp., which operates some 80 cruise ships owned by the following companies: • Carnival Cruise Lines

Fig. 11 — (Left) The company’s 1000-ft-long assembly building showing two vessels under construction. Fig. 12 — (Right) The LNG-powered vessel Incat under construction. The vessel will be in service between Argentina and Brazil.

• Holland America Line • Princess Cruises (owner of Sapphire Princess — Fig. 13) • Seabourn • Aida Cruises • Costa Cruises • Ibero Cruises • P&O Cruises (UK) • P&O Cruises (Australia). The business concept of the Miamiand London-based owner is to build and

operate cruise ships with aluminum superstructures capable of carrying large numbers of passengers on a holiday experience not very far and not very fast. These ships are not made in the United States nor even registered in the U.S.A., but the concept that drives the business is to serve a relatively affluent first-world market such as the United States and Europe. They are not “made in U.S.A.” but “made in the world.”

The world cruise industry is an example to us that if the United States is to be prominent in the world market, it must produce “made in the U.S.A.” products such as the great welded aluminum vessels being built at Austal, in Mobile, Ala. (see lead photo). We need also to apply our best efforts to ensure that a significant amount of the world market in shipbuilding and welding technology continues to be “conceived in the U.S.A.”◆

Fig. 13 — The Sapphire Princess is a sister ship to the MV Costa Concordia, which recently ran aground and capsized off the coast of Italy.

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Build Your Own Campfire Grill

By following 11 easy-tounderstand steps, you can soon be barbecuing with a unique, homemade grill BY BOB PELKY is a manufacturing/maintenance technician with Miller Electric Mfg. Co. (www.millerwelds.com), Appleton, Wis.

ne of the best ways for home shop enthusiasts and do-ityourselfers to hone their skills is to build projects that are of interest to them. Some build tools and equipment for their shop, while others build gadgets and accessories for recreational vehicles. This article focuses on a project you can do for fun in your home shop — build your own campfire grill. Most of the tripod-style campfire grills you find on the market today are cumbersome and unstable. This grill plan easily disassembles to allow for efficient use of space when traveling, and the grill grate is adjustable to just the right height for the heat level you need. Easy-to-build accessory holders and handles complete the package. To build your own grill, use the following directions. In addition, to serve as a visual aide, the drawing plans can be downloaded at Millerwelds.com/interests/projects/campfire-grill-stand/.

O

Materials Needed Here is a list of the materials you will need to build your campfire grill. Much of this can be found at your local steel supply store. • (3) 3-ft-long, 13⁄4-in. square tubes • (1) 33⁄4-ft-long, 13⁄4-in. square tube • (4) 8-in.-long, 13⁄4-in. square tubes • (1) 1-ft-long, 13⁄4-in. square tube • (4) 6-in.-long, 11⁄2-in. square tubes • (1) 8-in.-long, 11⁄2-in. square tube • (2) 191⁄4-in.-long, 1⁄8- × 1- × 1-in. angle irons 48

MARCH 2012

• (2) 211⁄4-in.-long, 1⁄8- × 1- × 1-in. angle irons • (2) 10-in.-long, 1⁄4- × 1-in. flat irons • (2) 8-in.-long, ¼-in. rods • (3) 3½-in.-long, 1⁄8-in. rods • (6) 5⁄16- × 1-in. bolts • (6) matching nuts • (4) matching washers • (2) 101⁄2- × 19-in. replacement gas grill grates • (2) 6-in.-long, 11⁄2-in. wood dowels

Tools Required For this project, gas metal arc welding (GMAW) is recommended. You will need a GMAW machine in the 140-A range — a light-duty unit you will find in many home shops. It is also recommended that you follow all proper safety measures by wearing an autodarkening or other type of helmet, a welding jacket, and welding gloves. Make sure to wear safety glasses at all times as well. Additional tools you will need are as follows: • C-clamps • Horizontal band saw (or cutoff wheel in your grinding tool or hand-held band saw) • 41⁄2-in. grinding tool • Drill or drill press • 5⁄16 drill bits • ½-in. wrench • Hammer • Ruler.

Construction Steps Building the Base Step 1: On one piece of 36-in., 1¾-in. tubing, drill two 5⁄16-in. holes starting 1 in. from each end, spaced 1 in. apart, and weld in 5⁄16-in. nuts. On the same side as the holes, weld 11⁄2-in. square tubing to the center of the tube. Step 2: Weld the remaining two pieces of the 1½-in. square tubing to the ends of the two pieces of 13⁄4-in. square tubing. Step 3: Piece together completed sides to finish the base.

Building the Upright Frame Step 4: Drill two 5⁄16-in. holes in one end of the 13⁄4- × 45-in. tubing. Weld the 5⁄16-in. nuts into holes. Clamp the 45-in. piece to the bench to prevent warping when welding. Measuring 12 in. up from the bottom, weld each 8- × 1¾-in. square tube to the base, spaced 4 in. apart. Step 5: Assemble to the base and firmly snug all bolts.

Building the Grill Grate Frame Step 6: Saw the corners of the angles to 45 deg. Step 7: Weld the square frame together. Weld 1½-in. square to the center of the 21¼-in. side.

Step 8: Weld the ¼- × 1-in. flat onto the angle along the sides of the 11⁄2-in. square for strength. Step 9: Weld on two 5⁄16-in. washers to each side 3½ in. apart to attach the handles.

Building the Accessory Holder Step 10: Drill two 5⁄16-in. holes in the 1¾-in. square tubing 2 in. apart for the handles. Weld 1½-in. square to the opposite ends of the holes. Bend three pieces of 1⁄8-in. square rod to form hooks and weld to the side for cooking utensils.

Building the Grill Grate Handles Step 11: Drill a ¼-in. hole in the center of each dowel end. Pound the rods into place to create handles. At this stage, you have built the entire structure. You can now brush all exposed welds smooth and paint as desired. The grill grates can be found at most hardware or home warehouse-style stores. You are now ready to take the grill with you on your next camping trip, or simply set it up in your backyard for your next barbecue.◆

STEP 1

STEP 2

STEP 3

STEP 4

— continued on next page

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STEP 5

STEP 6

STEP 7

STEP 8

STEP 9

STEP 10

STEP 11

STEP 11

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New AWS Spec Details Flux Cored and Metal Cored Electrodes

BY DENNIS CROCKETT

A new document introduces an open classification system to address new electrode types and alternate weld deposit requirements

Flux cored electrodes used for flux cored arc welding (FCAW) can be either gas shielded or self-shielded (no external shielding required). These tubular electrodes typically contain a fill mixture having nonmetallic components comprising 5 to 15% of the total electrode weight. Carbon steel flux cored electrodes for FCAW are currently classified under AWS A5.20/A5.20M, Specification for Carbon Steel Electrodes for Flux Cored Arc Welding. Low-alloy steel flux cored electrodes are classified under AWS A5.29/A5.29M, Specification for Low-Alloy Steel Electrodes for Flux Cored Arc Welding. Metal cored electrodes used for gas metal arc welding (GMAW) are always gas shielded. Like flux cored electrodes, metal cored electrodes are composite tubular electrodes with a fill mixture containing both metallic and nonmetallic components. However, the fill mixture in metal cored electrodes contains a relatively small amount of nonmetallic components, usually less than 2% of the total electrode weight. Carbon steel metal cored electrodes are currently classified under AWS A5.18/A5.18M, Specification for Carbon Steel Electrodes and Rods for Gas Shielded Arc Welding. Low-alloy metal cored electrodes are classified under AWS A5.28/A5.28M, Specification for LowAlloy Steel Electrodes and Rods for Gas Shielded Arc Welding. It is important to note that these four specifications utilize classification systems developed years ago. These are “fixed” classification systems with defined requirements for weld metal tensile strength, Charpy V-notch toughness, condition of heat treatment, etc. While still useful for the majority of applications, they do not adequately provide for the classification of electrodes designed for enhanced weld metal properties, for use with other commonly used shielding gases, for alternate conditions of heat treatment, or for use with advanced power sources.

New AWS A5.36/A5.36M Specification To address the issues noted above, the AWS A5 Committee on Filler Metals and Allied Materials has authorized the issuance of a new specification. This new document, developed by the AWS A5M Subcommittee, will be issued as AWS A5.36/A5.36M, Specification for Carbon and Low-Alloy Steel Flux Cored Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding. Listed below are the major features of this document:

• Provides for the classification of both the carbon steel flux cored electrodes and low-alloy steel flux cored electrodes previously classified under AWS A5.20/A5.20M and AWS A5.29/A5.29M, respectively • Transfers to this document for classification the carbon steel metal cored electrodes and low-alloy steel metal cored electrodes previously classified under AWS A5.18/A5.18M and AWS A5.28/A5.28M, respectively

DENNIS CROCKETT ([email protected]) is chair, AWS A5M Subcommittee on Carbon and Low­Alloy Steel Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding. WELDING JOURNAL

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Table 1 — Electrode Classifications Utilizing the Fixed Classification System Classification

E7XT­1C(a)

Shielding Gas

Electrode Type (Previously Classified Under)

E7XT­1M E7XT­5C E7XT­5M E7XT­6 E7XT­8 E7XT­9C E7XT­9M E7XT­12C E7XT­12M E70T­4 E7XT­7

CO2 75­85 Ar/bal CO2 CO2 75­85 Ar/bal CO2 None (self shielded) None (self shielded) CO2 75­85 Ar/bal CO2 CO2 75­85 Ar/bal CO2 None (self shielded) None (self shielded)

E70C­6M

75­85 Ar/bal CO2

• Introduces an “open” classification system to address new electrode types and alternate weld deposit requirements. This classification system is similar to the system already used in AWS specifications for the classification of submerged arc flux and electrode combinations. The flux cored and metal cored electrodes covered by the A5.36 specification utilize a classification system(s) based upon U.S. Customary Units. Electrodes covered by the A5.36M specification utilize a system(s) based upon the International System of Units (SI). For the purpose of discussion, specific examples are given only in U.S. Customary Units.

Fixed Classification System The fixed classification system has been carried over or “grandfathered” into this specification from AWS A5.20/ A5.20M (carbon steel flux cored electrodes) or from AWS A5.18/A5.18M (carbon steel metal cored electrodes) for the classification of those electrodes which, with the specific mechanical properties specified for them in A5.20/A5.20M or A5.18/A5.18M, have gained wide acceptance for single-pass and multiple-pass applications. These electrodes represent the majority of the market. The classifications of these electrodes for which the fixed classification system has been retained are given in Table 1.

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• X4 is the shielding gas designator (refer to Table 5 in AWS A5.36/A5.36M) • X5 designates the condition of heat treatment (“A” for as welded, “P” for postweld heat treated)

Flux Cored (AWS A5.20)

• X6 is the impact designator (refer to Table 3 in AWS A5.36/A5.36M) • X7 is the deposit composition designator(refer to Table 6 in AWS A5.36/ A5.36M)

Metal Cored (AWS A5.18)

(a) The “X” indicates the position of welding capability. A “0” is used to indicate flat and horizontal only. A “1” is used to indicate all­position capability.

• Retains the fixed classification system for those carbon steel flux cored and metal cored electrodes for which there is wide acceptance with their existing classification requirements

• TX3 is the electrode usability designator (refer to Table 4 in AWS A5.36/ A5.36M)

Open Classification System The flux cored and metal cored electrodes classified utilizing the “open” classification system are classified based upon the following: 1. The mechanical properties of the weld metal. (The A5.36 document offers the choice of eight different strength levels and eleven options for Charpy V-notch impact strength.) 2. The positions of welding for which the electrode is suitable. 3. Certain usability characteristics of the electrode, including the presence or absence of a shielding gas. (Three new electrode types, based upon usability, are introduced in A5.36.) 4. The nominal composition of the shielding gas, if any. (The list of classification shielding gases, as defined in AWS A5.32/A5.32M, has been expanded in A5.36.) The condition of postweld heat treatment (PWHT), if any. 5. Chemical composition of the weld metal. The classification designation system for flux cored and metal cored carbon and low-alloy steel electrodes under AWS A5.36/A5.36M follows. EX1X2TX3 – X4X5X6 – X7 where, • E designates an electrode • X1 is the tensile strength designator (refer to Table 2 in AWS A5.36/ A5.36M) • X2 is the position designator (“0” for flat and horizontal, “1” for all position)

The provision is made in the A5.36/ A5./36M specification for three different, optional supplemental designators that can be added to the end of the classification designation. It is important to note that these do not constitute part of the classification designation but are optional designators that can be added to indicate conformance to supplemental requirements. These optional designators are the diffusible hydrogen designator (HX) and the D or Q designators. The D and Q designators are used to indicate that the weld metal will meet supplemental mechanical property requirements when deposited under special welding procedures as specified for seismic applications (D designator) or for military applications (Q designator). The following are examples utilizing the open classification system in AWS A5.36. • E71T1-C1A2-CS1-H4. The complete classification designation for this electrode is E71T1-C1A2-CS1. It refers to an all-position, flux cored electrode that, when used with C1 (CO2) shielding gas and welded under the conditions prescribed in this specification, will produce weld metal in the as-welded condition having a tensile strength of 70–95 ksi and Charpy V-notch impact strength of at least 20 ft-lbf at –20°F. The weld deposit will meet the CS1 carbon steel composition requirements. The “H4” is not part of the electrode classification designation but is an optional, supplemental designator indicating the weld metal will have a maximum average diffusible hydrogen of 4 mL/100 g of deposited weld metal when tested under the conditions of the AWS A5.36 specification. • E80T5-M21P6-Ni2. This is a complete classification designation for a flat and horizontal flux cored electrode that, when used with M21 shielding gas (see Table 5 of AWS A5.36) under the conditions prescribed in the AWS A5.36 specification, will produce weld metal in the postweld heat-treated condition having a

tensile strength of 80–100 ksi and Charpy V-notch impact strength of at least 20 ftlbf at –60°F. The weld deposit composition conforms to the Ni2 composition requirements (see Table 6 of AWS A5.36). • E71T8-A4-Ni1. This is a complete classification designation for a self-shielded (no shielding gas designator appears), all-position flux cored electrode. It refers to an electrode that will produce weld metal that, when tested under the conditions prescribed in the AWS A5.36 specification, will have a tensile strength of 70–95 ksi and Charpy V-notch impact strength of at least 20 ft-lbf at –40°F in the as-welded condition. The weld deposit composition conforms to the Ni1 composition requirements for self-shielded electrodes. • E90T15-M22A2-D2. This is a complete classification designation for a flat and horizontal metal cored electrode. It refers to a metal cored electrode that, when used with M22 shielding gas (see Table 5 of AWS A5.36) under the conditions prescribed in this specification, will produce weld metal in the as-welded condition with a tensile strength of 90–110 ksi and Charpy V-notch impact strength of at least 20 ft-lbf at –20°F. The weld deposit composition conforms to the D2 composition requirements (see Table 6 of AWS A5.36). • E80T15S-M20. This is a complete

classification designation for a single-pass (only) metal cored electrode. Under the welding and testing conditions prescribed in the AWS A5.36 specification, this metal cored electrode, when used with M20 shielding gas (see Table 5 of AWS A5.36) will produce weld metal having a minimum tensile strength of 80 ksi.

Dual Classification Considerations Electrodes classified under one classification shall not be classified under any other classification in this specification with the exception of the following: 1. The electrodes classified utilizing the fixed classification system under A5.36 (as shown in Table 1) may also be classified utilizing the open classification system. 2. Electrodes may be classified using different shielding gases. 3. Electrodes may be classified both in the as-welded and in the postweld heat treated (PWHT) conditions. 4. Electrodes may be classified under A5.36 using U.S. Customary Units, or under A5.36M using the International System of Units (SI), or both. Standard dimensions based on either system may be used for sizing of electrodes or pack-

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aging, or both, under the A5.36 and A5.36M specifications. Electrodes classified under either A5.36 or A5.36M must meet all requirements for classification under that unit system. It is recognized that the documentation required by manufacturers, end users, and code bodies to transition from the classification of flux cored and metal cored electrodes from their previous classifications under AWS A5.20/A5.20M, AWS A5.29/A5.29M, AWS A5.18/ A5.18M, or AWS A5.28/A2.28M, as applicable, to their new classification designations under AWS A5.36/A5.36M requires a provision for a transition period. Therefore, flux cored electrodes may be classified under AWS A5.20/A5.20M (or AWS A5.29/A5.29M, as applicable), under AWS A5.36/A5.36M, or under both. Metal cored electrodes may be classified under AWS A5.18/A5.18M (or AWS A5.28/A5.28M, as applicable), under AWS A5.36/A5.36M, or under both. Manufacturers, at their option, may list both electrode classifications on the labels and packaging. The provision for dual classification provided in the specification expires at the end of year 2015. At that time classification to AWS A5.36/A5.36M is required.◆

WELDING JOURNAL

53

Celebrate the exciting world of welding. Attend your local AWS section meeting to watch our national presentation, learn more about careers in welding, meet individuals in your community who work in welding, and MORE! Visit: www.aws.org/w/a/sections/dist_list.html to find the AWS section closest to you.

          


Marine Welding Standards =<;:98<765432105/.-5,+00*5)3**5(0*12'& Best practical methods to weld steel hulls for ships, barges, mobile offshore drilling units, and other marine vessels. Includes information on steel plates, shapes, castings, and forgings, their selection, and their weldability. 118 pages, 72 illustrations, 9 tables, (Reaffirmed 2000). D3.5

$88/$66

=<;%$#"! !65'10-+0-5(0*12'&5.10 Covers the requirements for the underwater welding of structures or components in wet and dry environments at one-atmosphere and ambient atmospheres. Includes quali-

fication and inspection requirements. 142 pages, 48 figures, 13 tables, 7 forms, (2011).

formance qualification, welding techniques, and safety. 86 pages, (2004).

D3.6

D3.7

$100/$75

$76/$57

=<;#"!!65432105/.-5*32'35)3** (0*12'&

=<;8#"! !65,02/2+2.'5/.-5*2/2+2.' ./5(0*19-.3&52'+5-20-

Guidance on proven processes, techniques, and procedures for welding aluminum hulls and related ship structures. Applies chiefly to aluminum hulls over 30 ft. (9 m) long and made of sheet and plate 3/16 in. (4.8 mm) thick and greater. Sections on hull materials, construction preparation, welding equipment and processes, procedure and per-

Specifies the classification requirements for weld-through paint primers for paint manufacturers, based on the maximum coating thickness and welding procedure used in testing. 20 pages, (2010). D3.9

$52/$39

Structural Steel Welding Standards = ; = ; $#"! !65,+-3+3-*5(0*12'& .10,+00* For everyone involved in any phase of welding steel structures – engineers, detailers, fabricators, erectors, inspectors, etc. – the new D1.1 spells out the requirements for design, procedures, qualification, fabrication, inspection, and repair of pipe, plate, and structural shapes that are subject to either static or cyclical stresses. U.S. Customary and SI units of measurement. 570 pages, 21 annexes, 171 figures, 78 tables, (2010). D1.1

$524/$393

= ;<= ;<$#"!!65 ,+-3+3-*5(0*12'&5.10,00+5,+00* Covers arc welding of structural sheet/strip steels, including cold formed members, equal to or less than 3/16 in. (0.188 in./4.8 mm) nominal thickness and having a minimum specified yield point no greater than 80,000 psi (550 MPa). Applicable to welding of commonly used structural quality low-carbon hot rolled and cold rolled sheet and strip steel, with or without zinc coating (galvanized), to other structural sheet steels or to supporting structural steel members. Three weld types unique to sheet steel – arc spot, arc seam, and arc plug welds – are included. Includes sections on design, procedure and performance qualification, fabrication, inspection and stud welding as well as a commentary. 98 pages, 7 annexes, 44 figures, 11 tables, 3 forms (2008). D1.3

$120/$90

= ;= ;$#"! 65,+-3+3-*5(0*12'& .10702'/.-2'&5,+00* Covers welding of reinforcing steel in most reinforced concrete applications. Includes sections on allowable stresses, structural details, workmanship requirements, technique, procedure and performance qualification, and inspection. Figures clearly illustrate important welding considerations: unacceptable weld profiles, effective weld sizes, details of joints of anchorages, base plates, and inserts. Now addresses precast concrete components. Clarification on prequalified details and essential variables for fillet welds. New table illustrates ac 0ceptance criteria for macroetch tests. Approx. 85 pages, (2011). D1.4

$116/$87

= ;:$= ;:#"! !65-21&05(0*12'&5.10 Get the facts and code requirements for bridge building with carbon and low-alloy construction steels. Covers welding requirements of the American Association of State Highway and Transportation Officials (AASHTO) for welded highway bridges made from carbon and low-alloy construction steels. Chapters cover design of welded connections,

workmanship, technique, procedure and performance qualification, inspection, and stud welding. Features the latest AASHTO revisions and nondestructive examination requirements, as well as a section providing a “Fracture Control Plan for Nonredundant Bridge Members.” Revisions include: • Revised procedure, personnel, and test equipment inspection requirements • New materials and hybrid joint provisions

• New guidance on electroslag and narrow-gap ESW 478 pages, 17 annexes, 90 figures, 43 tables, 9 forms, commentary (2010). D1.5

$348/$261

= ;%= ;%$#"!!65,+-3+3-*5(0*12'& .10,+2'*05,+00*5 Covers requirements for welding stainless steel structural assemblies/components (excluding pressure vessels or

$  ,  45 =, Save 15% when you buy an AWS bundle. 3'1*05#"! "  = =57 • D1.1/D1.1M:2010, Structural Welding Code–Steel $524 • A2.4:2012, Standard Symbols for Welding, Brazing, and Nondestructive Examination $156 • A3.0M/A3.0:2010, Standard Welding Terms and Definitions $164 Individual catalog prices would be $844/$633…SAVE $127/$95 $844 3'1*05#"! "555 • D1.1/D1.1M:2010, Structural Welding Code–Steel • D1.2/D1.2M:2008, Structural Welding Code–Aluminum • D1.3/D1.3M:2008, Structural Welding Code–Sheet Steel • D1.4/D1.4M:2011, Structural Welding Code–Reinforcing Steel • D1.5M/D1.5:2010, Bridge Welding Code • D1.6/D1.6M:2007, Structural Welding Code–Stainless Steel

 

Individual catalog prices would be $1,548/$1,161…SAVE $232/$174  

3'1*05#"! "55 • A2.4:2012, Standard Symbols for Welding, Brazing, and Nondestructive Examination • D1.5M/D1.5:2010, Bridge Welding Code Individual catalog prices would be $504/$378…SAVE $76/$57

3'1*05=#"! "5,02253'1*055 • D1.1/D1.1M:2010, Structural Welding Code–Steel • D1.8/D1.8M:2009, Structural Welding Code–Seismic Supplement



 

$524 $200 $120 $116 $348 $240 $1,548    

$156 $348 $504 
 

$524 $132 $656

Individual catalog prices would be $628/$471…SAVE $98/$74  

3'1*05#"! 5)05$2'0-53'1*055 • D14.3/D14.3M:2010, Specification for Welding Earthmoving, Construction and Agricultural Equipment • B2.1/B2.1M:2009, Specification for Welding Procedure and Performance Qualification Individual catalog prices would be $320/$240…SAVE $48/$36  

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$80 $240 $320   


pressure piping) using gas metal arc welding, shielded metal arc welding, flux cored arc welding, submerged arc welding, and stud welding. Allows prequalified Welding Procedure Specifications for the austenitic stainless steels based on considerable experience with the most widely used stainless steels. Sections include design, procedure and performance qualification, fabrication, inspection, and stud welding. 292 pages, 14 annexes, 80 figures, 29 tables, (2007). D1.6

$240/$180

",",&:8=:25; /(;=3'(6=383':*3:=9*8;83':#8<(83' /(;7(;=<: Provides engineers and contractors with general direction and guidance on weld repairs, weld strengthening, and other procedures to correct problematic issues with existing structures made of steel (minimum yield strength of 100 ksi and minimum thickness of 1⁄8 inch), cast iron, and wrought iron. 52 pages, 4 tables, (2009). D1.7

$108/$81

",%",%&:/(;7(;*):0=)83' 5=/=8<.87:/99)=.=3( A supplement to D1.1, applicable to welded joints in seismic load resisting systems designed in accordance with the Seismic Provisions of AISC. Covers additional controls on detailing, materials, workmanship, testing, and inspection necessary to achieve adequate performance of welded steel structures under conditions of severe earthquakeinduced inelastic straining. Commentary offers guidance on interpreting and applying this supplement. 124 pages, 9 annexes, commentary, 22 figures, 8 tables, (2009). D1.8

$132/$99

-,+*)('*&+)%$'*#%"$!$ ***'%+*!+" These are the must-have references for engineers, structural designers, technologists, inspectors, welders, welding educators and others who need to understand this dynamic and evolving industry. Put all the facts at your fingertips and make sure you’re on the cutting edge with new and updated material. Here are five good reasons you should add these valuable editions to your library. The books represent: • The largest body of knowledge on welding available anywhere. • Practical, hands-on information that you can put to immediate use. • The most current information on best practices regarding safety, quality, and qualification issues. • Unparalleled authority—chapters are written by leading scientists, engineers, educators, and other technical and scientific experts. Everything is peer-reviewed for accuracy and timeliness. • The most valuable resource on welding on the market today, covering the entire spectrum of welding from science and technology, history, welding processes, and materials and applications.

83(6:#8(853&:5).=:&:0=)83':/78=37= *3:=7635)5' Presents the latest developments in the basic science and technology of welding, and general descriptions of processes, continues with chapters on the physics of welding and cutting; heat flow; welding metallurgy; design; test methods; residual stress; welding symbols; tooling and positioning; monitoring and control; mechanized, automated, and robotic techniques; economics; weld quality; inspection; qualification and certification; welding codes and standards; and safe practices. 932 pages, 17 chapters, 2 appendices, 530 illustrations, 168 tables, hardbound. 8" x 10", (2001). WHB-1.9

$192/$144

83(6:#8(853&:5).=:&:0=)83'

;57=<<=<&: *;(: Presents comprehensive information on welding and related processes. Contains detailed information on arc welding power sources; shielded metal arc, gas tungsten arc, gas metal arc, flux cored arc, submerged arc, and plasma arc welding processes. Includes chapters on electroslag welding, stud welding, oxyfuel gas welding, brazing, soldering, oxygen cutting, and arc cutting and gouging. 736 pages, 15 chapters, 260 line drawings, 100 photographs, 148 tables, hardbound. 8" x 10", (2004). WHB-2.9

$192/$144

83(6:#8(853&:5).=: &:0=)83'

;57=<<=<&: *;(: Over 600 pages of comprehensive information on solidstate and other welding and cutting processes. The book

includes chapters on resistance spot and seam welding, projection welding, flash and upset welding and highfrequency welding. In addition to a chapter on friction welding, a new chapter introduces friction stir welding. The most recent developments in beam technology are discussed in the greatly expanded chapters on laser beam welding and cutting and electron beam welding. A diverse array of processes are presented in chapters on the ultrasonic welding of metals, explosion welding, diffusion welding and diffusion brazing, adhesive bonding and thermal and cold spraying. The last chapter covers various other welding and cutting processes, including modernized water jet cutting. 669 pages, 15 chapters, 3 appendices, 438 illustrations, 59 tables; hardbound. 8" x 10", (2007) WHB-3.9

$192/$144

83(6:#8(853&:5).=:&:*(=;8*)<:*3 199)87*(853<&: *;(: Extensively revised and updated from the eighth edition, this comprehensive volume had more than 50 experts in materials and materials applications assure its accuracy and the currency of its content. It is a great reference source for engineers, educators, welding supervisors, and welders. Covers carbon and low-alloy steels; high-alloy steels; coated steels; tool and die steels; stainless and heat-resisting steels; clad and dissimilar metals; surfacing; cast irons; maintenance and repair welding; and underwater welding and cutting. Includes more than 500 tables, charts, and photos. 10 chapters, hardbound, 8" x 10", (2010). WHB-4.9

$192/$144

#8'6(6:#8(853&:5).=: &:*(=;8*)<:*3 199)87*(853<: : *;(:: Covers nonferrous metals, plastics, composites, and ceramics; specialized topics on maintenance and repair welding; underwater welding and cutting. Includes applications of the specific metals and processes, weldability, safe practices. Best copy available, 538 pages, 10 chapters, softbound. 81/2" x 101/2", (1996). WHB-3.8

$160/$120

#:+!#: >#/: +:# # :0#>"! :1 "  /#:1://1 !1>:/1! / • Vol. 1, 9th Edition: Welding Science & Technology • Vol. 2, 9th Edition: Welding Processes, Part 1 • Vol. 3, 9th Edition: Welding Processes, Part 2 • Vol. 4, 9th Edition: Materials & Applications, Part 1 • Vol. 3, 8th Edition: Materials & Applications, Part 1 WHB-ALL

$762/$572

#:#:0 :1 "   >#/: :  #//#/:1 //1 !1>:/1! / • Vol. 2, 9th Edition: Welding Processes, Part 1 • Vol. 3, 9th Edition: Welding Processes, Part 2 WHB-PRC

$288/$216

" 0 > 1":/! >#:1 #/ Choose individual Welding Handbook chapters for PDF download, at an economical price. SEE AWSPUBS.COM

>=<<=;:9;87=:<6543:8<:25;:10/:.=.-=;<,:+5;:*:75.9)=(=:7*(*)5'&:7*)):%%%$0#>"! ,

$20/$15

Featured Pubs 432130/./-4,1A2.4:2012, Standard Symbols for Welding, Brazing, and Nondestructive Examination Establishes a method of specifying certain welding, brazing, and nondestructive examination information by means of symbols. Contains detailed information and examples for the construction and interpretation of these symbols. This system provides a means of specifying welding or brazing operations and nondestructive examination, as well as the examination method, frequency, and extent. 150 pages, (2012). A2.4

$156/$117

A3.0M/A3.0:2010, Standard Welding Terms and Definitions Alphabetical glossary of over 1,400 standard terms and definitions for welding, brazing, soldering, resistance welding, etc., as well as hybrid processes. Each term has one clearly applicable definition, accurately reflecting the term’s use in the joining world. Includes figures to illustrate the use of terms. For completeness, nonstandard terms are also included. Contains a Master Chart of Welding and Allied Processes, and the Joining Method Chart. 160 pages, 62 figures, 5 tables (2010). A3.0

$164/$123

B1.10M/B1.10:2009, Guide for the Nondestructive Examination of Welds Addresses which examination method – visual, liquid penetrant, magnetic particle, radiographic, ultrasonic, electromagnetic (eddy current), or leak testing – best detects various types of discontinuities. Note: Does not address acceptance criteria. 64 pages, 30 figures, 4 tables, (2009), fourth edition. B1.10

$104/$78

B1.11:2000, Guide for the Visual Examination of Welds Provides guidance on visual examination of welds, including sections on prerequisites, fundamentals, surface conditions, and equipment. Sketches and color photographs illustrate common weld discontinuities. 48 pages, 3 annexes, 48 figures, (2000). B1.11

$104/$78

B2.1/B2.1M:2009, Specification for Welding Procedure and Performance Qualification Covers all fusion welding processes and an exhaustive array of materials used in metal fabrication. Specifies requirements for the qualification of welding procedures, and for performance qualification of welders and welding operators for manual, semiautomatic, mechanized, and automatic welding. 298 pages, 43 figures, 25 tables, 5 forms (2009). B2.1

$240/$180

B4.0:2007, Standard Methods for Mechanical Testing of Welds Describes the most common mechanical test methods applicable to welds and welded joints. Each test method gives details concerning specimen preparation, test parameters, testing procedures, and suggested report

forms. Acceptance criteria are not included. Three new weldability tests (WIC, trough, and GBOP) and resistance weld tests have been included in this new edition. (Note: Joint tests for brazements are covered in AWS C3.2M/C3.2.) U.S. Customary Units. 152 pages, 97 figures, (2007). B4.0

$104/$78

432130/./-4,1C1.1M/C1.1:2012, Recommended Practices for Resistance Welding Covers spot, seam, projection, flash, and upset welding, as well as weld bonding for uncoated and coated carbon and low-alloy steels, aluminum alloys, stainless steels, nickel, nickel-base alloys, cobalt-base alloys, copper and alloys, and titanium and alloys. Details equipment and setup, welding variables, joint preparation, cleaning, welding schedules and parameters, weld quality testing, safety, and health. Approx. 116 pages, (2012). C1.1

CALL FOR PRICE

+*)(',(&%&$1#"! ""1!!"1  "1"12"$1+$11"  !"" Covers common applications of the process, including drilling and transformation hardening. Describes equipment and procedures. Practical information, including figures and tables, should prove useful in determining capabilities in the processing of various materials. 142 pages, 85 figures, 8 tables, (2010). C7.2

$100/$75

0%)(0%)(',(&&$1

!12"1+ "  Covers welding requirements for any type of structure made from aluminum structural alloys, except aluminum pressure vessels and fluid-carrying pipelines. Includes sections on design of welded connections, procedure and performance qualification, fabrication, inspection, stud welding, and strengthening and repair of existing structures. A commentary offers guidance on interpreting and applying the code. 226 pages, 59 figures, 24 tables, (2008). D1.2

$200/$150

D9.1M/D9.1:2006, Sheet Metal Welding Code Covers arc and braze welding requirements for nonstructural sheet metal fabrications using commonly welded metals available in sheet form up to and including 3 gauge, or 6.4 mm (0.250 in.). Applications of the code include heating, ventilating, and air conditioning systems, food processing equipment, architectural sheet metal, and other nonstructural sheet metal applications. Sections include procedure and performance qualification, workmanship, and inspection. Nonmandatory annexes provide useful information on materials and processes. Not applicable when negative or positive pressure exceeds 30 kPa (5 psi). 70 pages, 29 figures, 10 tables, (2006). D9.1

$72/$54

D14.1/D14.1M:2005, Specification for Welding of Industrial and Mill Cranes and Other Material Handling Equipment Specifies requirements for welding of all principal structural weldments and all primary welds used to manufacture cranes for industrial, mill, powerhouse, and nuclear facilities. Also applies to other overhead material-handling machinery and equipment that support and transport loads within the design rating, vertically or horizontally, during normal operations. Additionally, when agreed upon between the owner and manufacturer, it may apply to loading caused by abnormal operations or environmental events, such as seismic loading. All provisions apply equally to strengthening and repairing of existing overhead cranes and material handling equipment. Contains figures and tables with prequalified joint details, allowable stress ranges, stress categories, and nondestructive examination techniques. Does not apply to construction or crawler cranes or welding of rails. 150 pages, 60 figures, 21 tables (2005). D14.1

$104/$78

D17.1:2010, Specification for Fusion Welding for Aerospace Applications Specifies general welding requirements for welding aircraft and space hardware. Includes fusion welding of aluminum-based, nickel-based, iron-based, cobaltbased, magnesium-based, and titanium-based alloys using arc and high energy beam welding processes. Includes sections on design of welded connections, personnel and procedure qualification, fabrication, inspection, repair of existing structures and nonflight hardware acceptance. Additional requirements cover repair welding of existing hardware. 98 pages, 7 annexes, commentary, 33 figures, 18 tables, (2011). D17.1

$160/$120

WI:2000, Welding Inspection Handbook This invaluable training reference helps inspectors, engineers, and welders evaluate the difference between discontinuities and rejectable defects. 254 pages 18 chapters, index, 108 figures, 16 tables, 61/2" x 9", (2000), third edition. WI

$76/$57

WIT-T:2008, Welding Inspection Technology For at-home study, this official reference textbook for the three-day AWS core seminar for CWI exam preparation is readable, informative, and comprehensive. 329 pages, 10 chapters, 379 figures and photographs, (2008). WIT-T

$272/$204

Brazing Handbook A comprehensive, organized survey of the basics of brazing, processes, and applications. Addresses the fundamentals of brazing, brazement design, brazing filler metals and fluxes, safety and health, and many other topics. Includes new chapters on induction brazing and diamond brazing. A must-have for all brazers, brazing engineers, and students. 740 pages, 36 chapters, 3 appendices, 308 figures, 116 reference tables, fifth edition, (2007). BRH

"" 11 "1 1  ""1 11 "  "1 1 "1

) )!  ""1!"1 11 12 1"")1 11! ""1! $1!1230/4
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$136/$102

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CONFERENCES Automated Welding Conference March 6, 7 Orlando, Fla. Talks will be given on a variety of topics, including tandem arc welding, hybrid welding, several hot wire processes, and the new SAT process from Sweden, as well as presentations on the latest in networking, laser beam welding, welding of aluminum, robotic inspection, and friction stir welding. Speakers will also discuss U.S. Army challenges, such as GMAW of titanium and the welding of ballistic steels.

FABTECH Canada March 20–22 Toronto, Canada With the growing success of FABTECH, North America’s largest metal forming, fabricating, welding, and finishing event, comes the launch of FABTECH Canada, located in the heart of Canada’s engineering and technology region. This is the only exclusive fabricating, welding, and metal forming event in Canada.

International Electron Beam Welding Conference March 26–30 Aachen, Germany The second International Electron Beam Welding Conference (IEBW) will bring together scientists, engineers, and technical personnel from around the globe involved in the research, development, and application of electron beam welding processes. IEBW is organized by the American Welding Society, German Welding Society, and International Institute of Welding.

5th International Brazing & Soldering Conference April 22–25 Las Vegas, Nev. Join hundreds of other professionals, scientists, and engineers from around the globe involved in the research, development, and application of brazing and soldering. The four-day conference will provide one of the most comprehensive technical programs available to the brazing and soldering community, as well as valuable networking, preconference educational programs, and exhibits where attendees can find out more about the latest trends, products, processes, and techniques available in the brazing and soldering industry.

The Energy Boom: Get on the Bandwagon June 12, 13 San Diego, Calif. The demands for new and improved welding technology from the expanding energy markets are starting to pay off in the development of superior hybrid welding processes, new filler metals, and a host of cladding procedures. These technologies are showing up in nuclear power plants, in coal-fired utilities, and especially in new 1700-mile-long pipelines designed to bring oil and natural gas to American markets. On the agenda are talks on Lincoln Electric’s new laser hot wire cladding process and the ICE process from ESAB in Sweden that is intended for windpower fabrication. Other topics will include the successes of the new P87 filler metal, the variety of applications for explosion welding, and, from Edison Welding Institute, a close look at the less-expensive plasma/GMA hybrid welding process.

15th Annual Aluminum Welding Conference September 18, 19 Seattle, Wash. A panel of distinguished aluminum industry experts will survey the state of the art in aluminum welding technology and practice. The 15th Aluminum Welding Conference will also provide several opportunities to network informally with speakers and other participants, as well as an exhibition showcasing products and services of interest to the aluminum welding industry. Aluminum lends itself to a wide variety of industrial applications because of its light weight, high strength-to-weight ratio, corrosion resistance, and other attributes. However, because its chemical and physical properties are different from those of steel, welding of aluminum requires special processes, techniques, and expertise.

FABTECH 2012 November 12–14 Las Vegas, Nev. North America’s largest metal forming, fabricating, welding, and finishing event heads to the Las Vegas Convention Center. If your job requires you to look for new ways to work smarter, operate leaner, and boost productivity, then you and your team need to attend FABTECH. Make plans now to attend your industry’s main event and you’ll find the products, resources, and ideas to strengthen your business and achieve your manufacturing goals.◆

For more information, please contact the AWS Conferences and Seminars Business Unit at (800) 443-9353, ext. 264, or e-mail [email protected]. You can also visit the Conference Department Web site at www.aws.org/conferences for upcoming conferences and registration information.

60

MARCH 2012

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COMING EVENTS

NOTE: A DIAMOND ( ♦) DENOTES AN AWS-SPONSORED EVENT.

♦Automated Welding Conf. March 6, 7. Orlando, Fla. Topics include laser, tandem arc, and hybrid welding; several hot wire processes; the new SAT process; networking; welding aluminum; robotic inspection; and friction stir welding. Sponsored by the American Welding Society. www.aws.org/conferences.

♦FABTECH Canada 2012. March 20–22. Toronto Congress Centre, Toronto, Ont., Canada. Sponsored by the American Welding Society, Society of Manufacturing Engineers, and Fabricators & Manufacturers Association, Int’l. A one-stop venue for welding, lasers, fabricating, metalforming, and other technologies tailored to the needs of Canadian manufacturing industries. Visit www.fabtechcanada.com; show updates will be posted on Twitter and LinkedIn.

♦2nd Int’l Electron Beam Welding Conf. March 26–30. Aachen, Germany. Cosponsored by AWS, the German Welding Society, and Int’l Institute of Welding. www.aws.org/conferences. Tube 2012, Int’l Tube and Pipe Trade Fair. March 26–30. The Fairgrounds, Düsseldorf, Germany. To exhibit in the North American Pavilion, contact Messe Düsseldorf North America, (312) 7815180; FAX (312) 781-5188; www.mdna.com. WESTEC 2012. March 27–29, Los Angeles Convention Center, Los Angeles, Calif. Sponsored by the Society of Manufacturing Engineers. www.westeconline.com. Japan Int’l Welding Show 2012. April 11–14. Intex Osaka, Osaka,

Japan. Sponsored by The Japan Welding Engineering Society and Sanpo Publications, Inc. Visit www.weldingshow.jp/english/. NASCC, North American Steel Construction Conf. April 18–20. Gaylord Texan Convention Center, Dallas, Tex. www.aisc.org/nascc.

♦5th Int’l Brazing and Soldering Conf. April 22–25. Red Rock Casino Resort Spa, Las Vegas, Nev. A joint activity of the American Welding Society and ASM International®, it will bring together scientists and engineers from around the world who are involved in the research, development, and application of brazing and soldering. www.asminternational.org/IBSC. GAWDA Spring Management Conf. April 28–May 1. Baltimore Marriott Waterfront, Baltimore, Md. Gases and Welding Distributors Assn. www.gawda.org/spring-management-conferences-2012. Offshore Technology Conf. April 30–May 3. Reliant Park, Houston, Tex. www.otc.org/2012.

♦AWS Weldmex. May 2–4. Mexico City, Mexico. Sponsored by the American Welding Society, the event will focus on welding and cutting products, including thermal spray, metal finishing, and safety equipment. The show co-locates with Metalform Mexico and FABTECH Mexico. www.weldmex.com. Manufacturing 4 the Future. May 8–10, Connecticut Convention Center, Hartford, Conn. Sponsored by the Society of Manufacturing Engineers. www.mfg4event.com.

TECHNICAL TRAINING Th Hobart Institute The In off Welding Technology offers fe our comprehensiv nsive Technical Training courses through the year ar! Upcoming start-dates: Prep fo for AWS Certifi fied Welding W Supervisor Exam Apr 30 : Nov 12

Prep fo for AWS Welding Inspect Ins or/Educator /E Exam

Welder training and qualification coupons

Apr 9 : May 14 : Jun 18 : Jul 23 : Sep 10 : Oct 22

Visual Inspection Ins Sep 5 : Nov 19

Destructive test equipment Full testing services

Welding fo for the Non Welder Apr 2 : Jun 4 : Aug 27 : Sep 24

Arc Welding Inspect nspection & Quality Control May 7 : Jun 11 : Jul Ju 16 : Oct 8 : Nov 26

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Liquid Penetrant & Magnetic Particle Inspection Mar 26 : Apr 23 : Aug 13 : Nov 5

1-800-332-9448 or visit us at www.weldi ding.org rg for more inf nformation. © 2012 Hobart Institute of Welding Technology, Troy, OH Stt. of Ohio Reg. No. 70-12-0064HT For info go to www.aws.org/ad-index

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MARCH 2012

For info go to www.aws.org/ad-index

9th Int’l Laser Technology Congress AKL ’12. May 9–11. Aachen, Germany. www.lasercongress.org/en/index.html. Montreal Manufacturing Technology Show. May 14–16, Place Bonaventure, Montreal, QC, Canada. Sponsored by the Society of Manufacturing Engineers. www.mmts.ca. Int’l Tube and Pipe Trade Fair and Aluminum/Non-Ferrous Trade Fair. May 28–31. ZAO Expocenter, Moscow, Russia. Organized by Messe Düsseldorf Moscow and Metal-Expo. Contact Messe Düsseldorf North America, (312) 781-5180, www.mdna.com. SME Annual Conf. June 3–5, Cleveland Marriott Downtown Hotel, Cleveland, Ohio. Sponsored by the Society of Manufacturing Engineers. www.sme.org/conference. 17th Beijing-Essen Welding and Cutting Fair. June 4–7. New China Int’l Exhibition Centre, Beijing, China. www.cmes.org/ essen/en/index.htm. North American Manufacturing Research Conf. (NAMRC). June 4–8, University of Notre Dame, South Bend, Ind. Sponsored by the Society of Manufacturing Engineers. www.sme.org/namrc. Global Petroleum Show. June 12–14. Stampede Park, Calgary, Alb., Canada. http://globalpetroleumshow.com.

♦The Energy Boom: Get on the Bandwagon. June 12, 13, San Diego, Calif. Sponsored by the American Welding Society. www.aws.org/conferences. Optimizing Operations through Continuous Improvement Conf. June 26–28. Loews Vanderbilt Hotel, Nashville, Tenn. Sponsored by Tube & Pipe Assn., Int’l; UK-based Int’l Tube Assn.; and Fabricators & Manufacturers Assn., Int’l; www.pipetubeconf.com/nashville.

For info go to www.aws.org/ad-index

Educational Opportunities Machinery Vibrations, Introduction. March 20–23, Indianapolis, Ind. Fee $1025. Vibration Institute, www.vibinst.org. Canadian Welding Bureau Courses. Welding inspection courses and preparation courses for Canadian General Standards Board and Canadian Nuclear Safety Commission certifications. The CWB Group. www.cwbgroup.org. Art Using Welding Technology Classes and Workshops. Miami, Fla. With artist and sculptor Sandra Garcia-Pardo. Meet the artist at www.theartlink.org; (786) 547-8681. ASM Int’l Courses. Numerous classes on welding, corrosion, failure analysis, metallography, heat treating, etc., presented in Materials Park, Ohio, online, webinars, on-site, videos, and DVDs; www.asminternational.org, search for “courses.” Automotive Body in White Training for Skilled Trades and Engineers. Orion, Mich. A five-day course covers operations, troubleshooting, error recovery programs, and safety procedures for automotive lines and integrated cells. Applied Mfg. Technologies; (248) 409-2000; www.appliedmfg.com. Basic and Advanced Welding Courses. Cleveland, Ohio. The Lincoln Electric Co.; www.lincolnelectric.com. Basics of Nonferrous Surface Preparation. Online course, six hours includes exam. Offered on the 15th of every month by The Society for Protective Coatings. Register at www.sspc.org/training. Boiler and Pressure Vessel Inspectors Training Courses and Seminars. Columbus, Ohio; www.nationalboard.org; (614) 8888320.

For info go to www.aws.org/ad-index

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CERTIFICATION SCHEDULE AWS Certification Schedule Certification Seminars, Code Clinics, and Examinations Certified Welding Inspector (CWI) SEMINAR DATES LOCATION Indianapolis, IN Mar. 11–16 Portland, OR Mar. 11–16 Phoenix, AZ Mar. 11–16 Boston, MA Mar. 18–23 Anchorage, AK Mar. 18–23 Chicago, IL Mar. 18–23 Mobile, AL Exam only Rochester, NY Exam only York, PA Exam only Miami, FL Mar. 25–30 Miami, FL Exam only Knoxville, TN Exam only Dallas, TX Apr. 15–20 St. Louis, MO Exam only Springfield, MO Apr. 15–20 Portland, ME Apr. 15–20 Las Vegas, NV Apr. 15–20 San Francisco, CA Apr. 29–May 4 Nashville, TN Apr. 29–May 4 Jacksonville, FL Apr. 29–May 4 Waco, TX Exam only Baltimore, MD May 6–11 Detroit, MI May 6–11 Albuquerque, NM May 6–11 Corpus Christi, TX May 6–11 Miami, FL May 6–11 Miami, FL Exam only Long Beach, CA Exam only Spokane, WA June 3–8 Oklahoma City, OK June 3–8 Birmingham, AL June 3–8 Hartford, CT June 10–15 Pittsburgh, PA June 10–15 Beaumont, TX June 10–15 Miami, FL Exam only

Certified Radiographic Interpreter (CRI) EXAM DATE Mar. 17 Mar. 17 Mar. 17 Mar. 24 Mar. 24 Mar. 24 Mar. 24 Mar. 24 Mar. 24 Mar. 31 Apr. 12 Apr. 14 Apr. 21 Apr. 21 Apr. 21 Apr. 21 Apr. 21 May 5 May 5 May 5 May 5 May 12 May 12 May 12 May 12 May 12 May 19 May 26 June 9 June 9 June 9 June 16 June 16 June 16 Aug. 18

9–Year Recertification Seminar for CWI/SCWI For current CWIs and SCWIs needing to meet education requirements without taking the exam. The exam can be taken at any site listed under Certified Welding Inspector. SEMINAR DATES EXAM DATE LOCATION Dallas, TX Mar. 12–17 No exam Miami, FL Apr. 16–21 No exam Sacramento, CA Apr. 30–May 5 No exam Pittsburgh, PA June 4–9 No exam San Diego, CA July 9–14 No exam Miami, FL July 16–21 No exam Certified Welding Supervisor (CWS) SEMINAR DATES LOCATION New Orleans, LA Apr. 16–20 Minneapolis, MN July 16–20 CWS exams are also given at all CWI exam sites.

EXAM DATE Apr. 21 July 21

LOCATION Houston, TX Las Vegas, NV Miami, FL Dallas, TX

SEMINAR DATES Apr. 16–20 May 7–11 June 4–8 July 16–20

EXAM DATE Apr. 21 May 12 June 9 July 21

The CRI certification can be a stand-alone credential or can exempt you from your next 9-Year Recertification. Certified Welding Sales Representative (CWSR) CWSR exams will be given at CWI exam sites. Certified Welding Educator (CWE) Seminar and exam are given at all sites listed under Certified Welding Inspector. Seminar attendees will not attend the Code Clinic portion of the seminar (usually the first two days). Certified Robotic Arc Welding (CRAW) WEEKS OF, FOLLOWED BY LOCATION AND PHONE NUMBER May 11, Aug. 10, Nov. 9 at ABB, Inc., Auburn Hills, MI; (248) 391–8421 May 21, Aug. 20, Dec. 3 at Genesis-Systems Group, Davenport, IA; (563) 445-5688 Mar. 2, Oct. 22, Oct. 26 at Lincoln Electric Co., Cleveland, OH; (216) 383-8542 Apr. 23, July 9, Oct. 15 at OTC Daihen, Inc., Tipp City, OH; (937) 667-0800 Mar. 12, May 7, July 9, Sept. 10, Nov. 5 at Wolf Robotics, Fort Collins, CO; (970) 225-7736 On request at MATC, Milwaukee, WI; (414) 297-6996 Certified Welding Engineer (CWEng) and Senior Certified Welding Inspector (SCWI) Exams can be taken at any site listed under Certified Welding Inspector. No preparatory seminar is offered. Advanced Visual Inspection Workshop SEMINAR DATES LOCATION Miami, FL May 17, 18 Miami, FL Aug. 16, 17

EXAM DATE May 19 Aug. 18

International CWI Courses and Exams Schedules Please visit www.aws.org/certification/inter_contact.html.

IMPORTANT: This schedule is subject to change without notice. Applications are to be received at least six weeks prior to the seminar/exam or exam. Applications received after that time will be assessed a $250 Fast Track fee. Please verify application deadline dates by visiting our website www.aws.org/certification/docs/schedules.html. Verify your event dates with the Certification Dept. to confirm your course status before making travel plans. For information on AWS seminars and certification programs, visit www.aws.org/certification or call (800/305) 443-9353, ext. 273, for Certification; or ext. 455 for Seminars. Apply early to avoid paying the $250 Fast Track fee.

64

MARCH 2012

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Friends and Colleagues:

The American Welding Society established the honor of Counselor to recognize individual members for a career of distinguished organizational leadership that has enhanced the image and impact of the welding industry. Election as a Counselor shall be based on an individual’s career of outstanding accomplishment. To be eligible for appointment, an individual shall have demonstrated his or her leadership in the welding industry by one or more of the following: • Leadership of or within an organization that has made a substantial contribution to the welding industry. The individual’s organization shall have shown an ongoing commitment to the industry, as evidenced by support of participation of its employees in industry activities. • Leadership of or within an organization that has made a substantial contribution to training and vocational education in the welding industry. The individual’s organization shall have shown an ongoing commitment to the industry, as evidenced by support of participation of its employee in industry activities. For specifics on the nomination requirements, please contact Wendy Sue Reeve at AWS headquarters in Miami, or simply follow the instructions on the Counselor nomination form in this issue of the Welding Journal. The deadline for submission is July 1, 2012. The committee looks forward to receiving these nominations for 2013 consideration.

Sincerely, Alfred F. Fleury Chair, Counselor Selection Committee

BLIND PERF

Nomination of AWS Counselor I.

HISTORY AND BACKGROUND In 1999, the American Welding Society established the honor of Counselor to recognize individual members for a career of distinguished organizational leadership that has enhanced the image and impact of the welding industry. Election as a Counselor shall be based on an individual’s career of outstanding accomplishment. To be eligible for appointment, an individual shall have demonstrated his or her leadership in the welding industry by one or more of the following: • Leadership of or within an organization that has made a substantial contribution to the welding industry. (The individual’s organization shall have shown an ongoing commitment to the industry, as evidenced by support of participation of its employees in industry activities such as AWS, IIW, WRC, SkillsUSA, NEMA, NSRP SP7 or other similar groups.) • Leadership of or within an organization that has made substantial contribution to training and vocational education in the welding industry. (The individual’s organization shall have shown an ongoing commitment to the industry, as evidenced by support of partici pation of its employees in industry activities such as AWS, IIW, WRC, SkillsUSA, NEMA, NSRP SP7 or other similar groups.) II. RULES A. B. C. D. E. F. G.

Candidates for Counselor shall have at least 10 years of membership in AWS. Each candidate for Counselor shall be nominated by at least five members of the Society. Nominations shall be submitted on the official form available from AWS headquarters. Nominations must be submitted to AWS headquarters no later than July 1 of the year prior to that in which the award is to be presented. Nominations shall remain valid for three years. All information on nominees will be held in strict confidence. Candidates who have been elected as Fellows of AWS shall not be eligible for election as Counselors. Candidates may not be nominated for both of these awards at the same time.

III. NUMBER OF COUNSELORS TO BE SELECTED Maximum of 10 Counselors selected each year. Return completed Counselor nomination package to: Wendy S. Reeve American Welding Society Senior Manager Award Programs and Administrative Support 550 N.W. LeJeune Road Miami, FL 33126 Telephone: 800-443-9353, extension 293

SUBMISSION DEADLINE: July 1, 2012

CLASS OF 2013

(please type or print in black ink)

COUNSELOR NOMINATION FORM DATE_________________NAME OF CANDIDATE________________________________________________________________________ AWS MEMBER NO.___________________________YEARS OF AWS MEMBERSHIP____________________________________________ HOME ADDRESS____________________________________________________________________________________________________ CITY_______________________________________________STATE________ZIP CODE__________PHONE________________________ PRESENT COMPANY/INSTITUTION AFFILIATION_______________________________________________________________________ TITLE/POSITION____________________________________________________________________________________________________ BUSINESS ADDRESS________________________________________________________________________________________________ CITY______________________________________________STATE________ZIP CODE__________PHONE_________________________ ACADEMIC BACKGROUND, AS APPLICABLE: INSTITUTION______________________________________________________________________________________________________ MAJOR & MINOR__________________________________________________________________________________________________ DEGREES OR CERTIFICATES/YEAR____________________________________________________________________________________ LICENSED PROFESSIONAL ENGINEER: YES_________NO__________ STATE______________________________________________ SIGNIFICANT WORK EXPERIENCE: COMPANY/CITY/STATE_____________________________________________________________________________________________ POSITION____________________________________________________________________________YEARS_______________________ COMPANY/CITY/STATE_____________________________________________________________________________________________ POSITION____________________________________________________________________________YEARS_______________________ SUMMARIZE MAJOR CONTRIBUTIONS IN THESE POSITIONS: __________________________________________________________________________________________________________________ __________________________________________________________________________________________________________________ __________________________________________________________________________________________________________________ IT IS MANDATORY THAT A CITATION (50 TO 100 WORDS, USE SEPARATE SHEET) INDICATING WHY THE NOMINEE SHOULD BE SELECTED AS AN AWS COUNSELOR ACCOMPANY THE NOMINATION PACKET. IF NOMINEE IS SELECTED, THIS STATEMENT MAY BE INCORPORATED WITHIN THE CITATION CERTIFICATE. **MOST IMPORTANT** The Counselor Selection Committee criteria are strongly based on and extracted from the categories identified below. All information and support material provided by the candidate’s Counselor Proposer, Nominating Members and peers are considered. SUBMITTED BY: PROPOSER_______________________________________________ AWS Member No.___________________ The proposer will serve as the contact if the Selection Committee requires further information. The proposer is encouraged to include a detailed biography of the candidate and letters of recommendation from individuals describing the specific accomplishments of the candidate. Signatures on this nominating form, or supporting letters from each nominator, are required from four AWS members in addition to the proposer. Signatures may be acquired by photocopying the original and transmitting to each nominating member. Once the signatures are secured, the total package should be submitted.

NOMINATING MEMBER:___________________________________Print Name___________________________________ AWS Member No.______________ NOMINATING MEMBER:___________________________________Print Name___________________________________ AWS Member No.______________ NOMINATING MEMBER:___________________________________Print Name___________________________________ AWS Member No.______________ NOMINATING MEMBER:___________________________________Print Name___________________________________ AWS Member No.______________

SUBMISSION DEADLINE JULY 1, 2012

Register today.

the world of brazing and soldering. ASM International® and the American Welding Society again team to organize this four-day technical event. Recognized by industry professionals as the world’s premier event for the brazing and soldering community, IBSC brings together scientists and engineers from around the world who are involved in the research, development, and application of brazing and soldering. • Hear renown speakers like Dr. Steven Liu and Eric Slezak • Connect with colleagues during professional seminars on Sunday • Bond with industry leaders, customers and friends at Monday evening’s welcome reception and Tuesday night’s poolside Viva Las Vegas social

Exposition and Sponsorship The IBSC Exposition provides exhibitors with a forum to showcase the latest trends, products, processes and techniques in the industry. Traditional and custom exposition and sponsorship opportunities are available. Secure your exhibit space today! Visit www.asminternational.org/ibsc for the latest conference information and registration.

Be part of the future of brazing and soldering technology. Plan to attend IBSC 2012. Register today.

Visit www.asminternational.org/ibsc for the latest conference information and registration.

SOCIETYNEWS BY HOWARD M. WOODWARD [email protected]

2011 Extraordinary Welding Award Presented John Mendoza, AWS 2011 president, named the U.S. Navy’s USS Freedom LCS 1 to receive the 2011 AWS Extraordinary Welding Award. It is the first Littoral Combat Ship (LCS) of the U.S. Navy to feature deckhouse and superstructure panels fabricated from aluminum extrusions that were friction stir welded. The friction stir welded aluminum deckhouse is very flat, which, combined with an angular design, makes it difficult for radar systems to spot. Many creative people contributed to move the USS Freedom from concept to reality. Cited were John DeLoach, manager, welding, and Maria Posada, technology lead of friction stir welding technologies within the Welding, Processing and NDE Branch NAVSEA, Naval Surface Warfare Center. Also honored were officials from Friction Stir Link, Inc.: John F. Hinrichs, VP technology; Christopher Smith, VP engineering and operations; Scott Gillis, design engineer; and Dan Rawson, a design and manufacturing engineer. Other major contributors who could not attend the event were AWS District 12 Director Dan Roland and Bruce Halverson, from Marinette Marine Fincantieri, and Westin Allen, Friction Stir Link, Inc. The AWS Extraordinary Welding Award is presented for technical design for outstanding development in welded fabrication recognizing welding excellence in construction, fabrication, and manufacturing, and to designate those welded structures whose purpose has historical importance or an influence on history. Built by Marinette Marine, Marinette, Wis., the USS Freedom LCS 1 keel was laid June 2, 2005, and it was commissioned Nov. 8, 2008. Its home port is San Diego, Calif. The Freedom’s propulsion system uses two diesel power plants and two RollsRoyce MT30 gas turbines with steerable water jet propulsion. Its overall length is 378 ft, beam is 57.4 ft, with a draft of 12.8 ft, and weighs about 3000 metric tons. The

John DeLoach (left) and Maria Posada, from the Naval Surface Warfare Center, accept the Extraordinary Welding Award from John Mendoza, AWS 2011 president.

Sharing in the presentation are (from left) John Hinrichs, Christopher Smith, Scott Gillis, and Dan Rawson who worked on making the LCS 1 a reality. Not shown are major contributors Bruce Halverson and AWS District 12 Director Dan Roland from Marinette Marine Fincantieri, and Westin Allen from Friction Stir Link, Inc.

The “Fast, Focused, Fearless” USS Freedom LCS 1 uses innovative materials and joining methods to make it stronger, lighter weight, and difficult to spot on radar. light aluminum deckhouse and superstructure panels help it to move faster than 40 knots. Its crew ranges from 15 to 50

core members, up to 75 with aviation detachments. The ship’s seal proclaims its bragging rights, “Fast, Focused, Fearless.”

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Tech Topics Standards Approved by ANSI A5.36/A5.36M:2012, Specification for Carbon and Low-Alloy Steel Flux Cored Electrodes for Flux Cored Arc Welding and Metal Cored Electrodes for Gas Metal Arc Welding. Approved 12/20/11. G2.5/G2.5M:2012, Guide for the Fusion Welding of Zirconium and Zirconium Alloys. Approved 1/17/12. A5.22/A5.22M:2012, Specification for Stainless Steel Flux Cored and Metal Cored Welding Electrodes and Rods. Approved 1/17/12.

Two New Standards Projects Development work has begun on a revision of A5.24 and a new standard, D14.9. Affected individuals are invited to contribute to this work. Contact the staff representative shown for complete information. Participation on AWS Technical Committees and Subcommittees is open to all persons. A5.24/A5.24M:20XX, Specification for Zirconium and Zirconium-Alloy Welding Electrodes and Rods. This specification prescribes the requirements for classification of zirconium and zirconium alloy electrodes and rods for GTA, GMA, and PA welding. The compositions specified for each classification represent the latest state of the art. Additional requirements are included for testing procedures, manufacture, sizes, lengths, and packaging. A guide is appended to the specification as a source of information concerning the classification system employed and the intended use of the zirconium alloy filler metal. Stakeholders: Welding industry. A. Diaz, ext. 304. D14.9/D14.9M:20XX, Specification for the Welding of Hydraulic Cylinders. This specification establishes definitions and

provides hydraulic industry-specific details as they relate to base materials, consumables, weld joint design, welding process controls, workmanship and quality requirements, inspection, repair, and modification. Stakeholders: hydraulic cylinders industry. M. Rubin, ext. 215.

Standards for Public Review B2.4:20XX, Specification for Welding Procedure and Performance Qualification for Thermoplastics. $25. 3/19/12. B5.16:20XX, Specification for the Qualification of Welding Engineers. $25. 3/19/12. D9.1M/D9.1:20XX, Sheet Metal Welding Code. $42. 3/19/12. D14.4/D14.4M:20XX, Specification for the Design of Welded Joints in Machinery and Equipment. $69. 3/12/12. AWS was approved as an accredited standards-preparing organization by the American National Standards Institute (ANSI) in 1979. AWS rules, as approved by ANSI, require that all standards be open to public review for comment during the approval process. The above revised standards were submitted for public review with the review expiration dates shown. To order draft copies, contact Rosalinda O’Neill, [email protected], (305) 4439353, ext. 451.

Technical Committee Meetings All AWS technical committee meetings are open to the public. To attend a meeting, call the staff secretary, (305) 4439353, at the extension shown. March 13–16, D1 Committee on Structural Welding. San Diego, Calif. M. Rubin, ext. 215. March 20, 21. A5 Committee on Filler Metals and Allied Materials. Orlando, Fla. R. Gupta, ext. 301.

March 21, A5T Subcommittee on Filler Metal Procurement Guidelines. Orlando, Fla. R. Gupta, ext. 301. March 22, A5A Subcommittee on Carbon and Low-Alloy Steel Electrodes and Rods for Shielded Metal Arc and Oxyfuel Gas Welding. Orlando, Fla. R. Gupta, ext. 301. April 17–19, D14 Committee on Machinery and Equipment. Miami, Fla. M. Rubin, ext. 215. April 17–19, D14B Subcommittee on General Design and Practices. Miami, Fla. M. Rubin, ext. 215. April 17–19, D14C Subcommittee on Earthmoving and Construction Equipment. Miami, Fla. M. Rubin, ext. 215. April 17–19, D14E Subcommittee on Welding of Presses and Industrial and Mill Cranes. Miami, Fla. M. Rubin, ext. 215. April 17–19, D14G Subcommittee on Welding of Rotating Equipment. Miami, Fla. M. Rubin, ext. 215. April 17–19, D14I Subcommittee on Hydraulic Cylinders. Miami, Fla. M. Rubin, ext. 215. April 24, B2E Subcommittee on Soldering Qualification. Las Vegas, Nev. A. Diaz, ext. 304. April 24, B2D Subcommittee on Standard Welding Procedure Specification. Las Vegas, Nev. A. Diaz, ext. 304. April 25, B2C Subcommittee on Materials. Las Vegas, Nev. A. Diaz, ext. 304. April 25, B2B Subcommittee on Welding Qualifications. Las Vegas, Nev. A. Diaz, ext. 304. April 26, B2 Committee on Procedure and Performance Qualification. Las Vegas, Nev. A. Diaz, ext. 304. April 25, 26, C3 Committee and Subcommittees on Brazing and Soldering. Las Vegas, Nev. S. Borrero, ext. 311.

Opportunities to Contribute to AWS Welding Standards and Codes Robotic and Automatic Welding The D16 Committee on Robotic and Automatic Welding seeks general interest and educators to help revise: D16.1M/ D16.1, Specification for Robotic Arc Welding Safety; D16.2M/D16.2, Guide for Components of Robotic and Automatic Arc Welding Installations; D16.4M/D16.4, Specification for the Qualification of Robotic Arc Welding Personnel. Brian McGrath, [email protected]; ext. 311. Soldering; Joining Nickel Alloys The B2E Subcommittee on Soldering Qualifications; G2C Subcommittee on Nickel Alloys to review B2.3/B2.3M, Specification for Soldering Procedures and Performance Qualification. Contact Steve Hedrick, [email protected]; ext. 305. 74

MARCH 2012

Local Heat Treating of Pipe Work The D10P Subcommittee for Local Heat Treating of Pipe to revise D10.10, Recommended Practices for Local Heating of Welds in Piping and Tubing. Contact B. McGrath, [email protected]; ext. 311. Magnesium Alloy Filler Metals A5L Subcommittee on Magnesium Alloy Filler Metals to assist in the updating of AWS A5.19-92 (R2006), Specification for Magnesium Alloy Welding Electrodes and Rods. Contact Rakesh Gupta, [email protected], ext. 301. Soldering; Joining Nickel Alloys The B2E Subcommittee on Soldering Qualifications; G2C Subcommittee on Nickel Alloys to review B2.3/B2.3M, Specification for Soldering Procedures and

Performance Qualification. Alex Diaz, [email protected]; ext. 304. Thermal Spray C2 Committee on Thermal Spraying to update C2.16, Guide for Thermal Spray Operator Qualification; C2.21, Specification for Thermal Spray Equipment Acceptance Inspection; and C2.25, Specification for Thermal Spray Feedstock — Solid and Composite Wire and Ceramic Rods. Surfacing Industrial Mill Rolls D14H Subcommittee on Surfacing and Reconditioning of Industrial Mill Rolls to revise AWS D14.7, Recommended Practices for Surfacing and Reconditioning of Industrial Mill Rolls. Contact Matt Rubin, [email protected], ext. 215.

New AWS Supporters Sustaining Members Abtrex Industries, Inc. 59640 Market St. South Bend, IN 46614 Representative: Keith Byars www.abtrex.com Abtrex Industries fabricates carbon, stainless steel, and plastic tanks for the steel and chemical-processing industries. It manufactures pipe weldments and classifying equipment for the power-generation and mining industries. Since 1969, its specialty has been making abrasion- and corrosion-resistant linings and coatings, using rubber, PVC, FPP, and technical thin films. Fish & Associates, Inc. 3148 Deming Way, Ste. 160 Middleton, WI 53562 Representative: Philip E. Fish www.fishassoc.com Founded in 2001, Fish & Associates provides quality assurance programs, design and detailing consultation, structural and special inspection services, nondestructive testing, project management, owner’s representation and related services for both public and private sector clients in the building, transportation, and infrastructure areas. The company is a certified small business enterprise that is authorized for professional engineering practice by the Wisconsin Department of Registration and Licensing. Hayes Mechanical 5959 S. Harlem Ave. Chicago, IL 60638 Representative: Jamie D. Walker www.hayesmechanical.com Hayes Mechanical, founded in 1918, is a pioneer in the boiler, construction, and repair industry. It is a union contractor holding five ASME Code and the NBIC “R” stamp(s). Through a steady wellplanned growth program, the company has become a leading, full-service contractor offering boiler, piping, sheet metal, plumbing, and HVAC services.

Supporting Companies Control Total de Calidad C. Fuente De Diana No. 165 Col. Metropolitana, 2da. Seccion Nezahualcoyotl, 57740, Mexico

AWS Member Counts February 1, 2012 Grades Sustaining ......................................522 Supporting .....................................303 Educational ...................................585 Affiliate..........................................476 Welding Distributor........................55 Total Corporate ..........................1,941 Individual .................................58,335 Student + Transitional ...............11,575 Total Members .........................69,910

Distefano Technology & Mfg. Co. 3838 S. 108 St. Omaha, NE 68144 Affiliate Companies John Beever Australia Pty. Ltd. 78 Berkshire Rd., North Sunshine Victoria 3020, Australia Matrix Service, Inc. 5100 E. Skelly Dr. 700 Tulsa, OK 74135 Multicare Safety & Industrial Inspections LLC PB 121089 Al Ghusais Dubai, UAE

District Director Awards

Pacific Stair Corp. 8690 Stair Way NE Salem, OR 97305

District 8 Director Joe Livesay has nominated the following members for this award.

Smith’s Welding and Fabrication 1631 N. 4th Ave. Altoona, PA 16601

Greater Huntsville Section Frank Miller, Randy Hammond, and Jim Higdon.

Service Machine PO Box 2083, 12421 Maple St. Ashland, VA 23005

Nashville Section Charles Fredericks, Tim Singleton, and Greg Ralphs.

Welding Distributors

Northeast Mississippi Section Tavares Irions, George Smith, and Ricky Collier.

Educational Institutions Indiana County Technology Center 441 Hamill Rd. Indiana, PA 15701

The District Director Award provides a means for District directors to recognize individuals who have contributed their time and effort to benefit the affairs of their local Sections and/or District.

Kankakee Community College 100 College Dr. Kankakee, IL 60901 LoneStar College System – CyFair 9191 Barker Cypress Rd. Cypress, TX 77433

Nominate Your Candidate for the M.I.T. Prof. Masubuchi Award November 5, 2012, is the deadline for submitting nominations for the 2013 Prof. Koichi Masubuchi Award. This award is presented each year to one person, 40 years old or younger, who has made significant contributions to the advancement of materials joining through

research and development. Nominations should include a description of the candidate’s experience, list of publications, honors, and awards, and at least three letters of recommendation from fellow researchers. This award is sponsored by the Dept.

of Ocean Engineering at Massachusetts Institute of Technology (M.I.T.), this award includes a $5000 honorarium. E-mail your nomination package to Todd A. Palmer, assistant professor, The Pennsylvania State University, [email protected].

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Member-Get-A-Member Campaign Listed below are the members participating in the 2011–2012 AWS MemberGet-A-Member Campaign. Standings are as of January 20. For campaign rules and a prize list, see page 85 of this Welding Journal. For complete campaign rules, visit www.aws.org/mgm. Call the AWS Membership Department at (800) 4439353, ext. 480, with any questions about your member-proposer status. Winners’ Circle Listed are the sponsors of 20 or more Individual Members per year, since June 1, 1999. The superscript denotes the number of years the member has earned Winners’ Circle status. E. Ezell, Mobile8 J. Compton, San Fernando Valley7 J. Merzthal, Peru2 G. Taylor, Pascagoula2 L. Taylor, Pascagoula2 B. Chin, Auburn1 S. Esders, Detroit1 M. Haggard, Inland Empire1 M. Karagoulis, Detroit1 S. McGill, NE Tennessee1 B. Mikeska, Houston1 W. Shreve, Fox Valley1 T. Weaver, Johnstown/Altoona1 G. Woomer, Johnstown/Altoona1 R. Wray, Nebraska1 President’s Club Sponsored 3–8 new members M. Pelegrino, Chicago — 10 E. Ezell, Mobile — 7 J. Walker, Blackhawk — 6 T. Palmer, Atlanta — 5 G. Bish, Atlanta — 3 B. Goerg, Fox Valley — 3

D. Hale, East Texas — 3 J. Miller, Oklahoma City — 3 G. Mulee, South Carolina — 3 P. Phelps, Western Carolina — 3 D. Wright, Kansas City — 3 President’s Honor Roll Sponsored 2 new members T. Baber, San Fernando Valley T. Baldwin, Atlanta D. Biddle, Milwaukee M. Boggs, Stark Central O. Burrion, S. Florida G. Fehrman, Philadelphia J. Gordy, Houston G. Holl, Lexington G. Jacobson, Cumberland Valley J. Mueller, Ozark G. Sanford, Houston H. Suthar, Charlotte T. White, Pittsburgh C. Whitesell, Tulsa Student Sponsors M. Pelegrino, Chicago — 90 G. Bish, Atlanta — 50 R. Belluzzi, New York — 34 M. Box, Mobile — 34 R. Hammond, Birmingham — 32 A. Alvarez, Houston – 27 D. Berger, New Orleans — 27 D. Saunders, Lakeshore — 27 M. Anderson, Indiana — 24 H. Hughes, Mahoning Valley — 24 S. Siviski, Maine — 24 W. England, W. Michigan — 23 M. Boggs, Stark Central — 22 G. Gammill, NE Mississippi — 21 R. Huston, Olympic — 20 J. Fox, NW Ohio — 19

T. Palmer, Atlanta — 18 A. Baughman, Stark Central — 17 J. Bruskotter, New Orleans — 17 J. Ciaramitaro, N. Central Florida — 17 W. Davis, Syracuse — 17 J. Dawson, Pittsburgh — 17 C. Donnell, NW Ohio — 17 R. Evans, Siouxland — 17 R. Wahrman, Triangle — 17 N. Baughman, Stark Central — 16 R. Jones, Houston — 16 S. Miner, San Francisco — 16 E. Norman, Ozark — 16 R. Richwine, Indiana — 6 S. Robeson, Cumberland Valley — 15 J. Daugherty, Louisville — 14 D. Pickering, Central Arkansas — 4 C. Daily, Puget Sound — 12 R. Hutchinson, Long Bch/Or. Cty — 11 J. Johnson, Madison-Beloit — 11 D. Schnalzer, Lehigh Valley — 11 E. Ramsey, Johnstown-Altoona — 10 R. Simpson, Charlotte — 10 C. Kipp, Lehigh Valley — 9 B. Wenzel, Sacramento — 9 J. McCarty, St. Louis — 7 J. Boyer, Lancaster — 6 R. Ledford Jr., Birmingham — 6 S. Poe, Central Michigan — 6 J. Ginther, Pittsburgh — 5 J. McCarty, St. Louis — 7 T. Moore, New Orleans — 5 W. Wilson, New Orleans — 5 J. Crocker, N. Texas — 4 C. Hobson, Olympic Section — 4 A. Reis, Pittsburgh — 4 H. Rendon, Rio Grande Valley — 4 B. Amos, Mobile — 3 S. Colton, Arizona — 3 P. Deslatte, New Orleans — 3

Honorary Meritorious Awards The deadline for nominating candidates for these awards is December 31 prior to the year of the awards presentations. Send candidate materials to Wendy Sue Reeve, [email protected]; 550 NW LeJeune Rd., Miami, FL 33126. William Irrgang Memorial Award This award is given to the individual who has done the most over the past five years to enhance the Society’s goal of advancing the science and technology of welding. It includes a $2500 honorarium and a certificate. International Meritorious Certificate Award This honor recognizes recipients’ significant contributions to the welding industry for service to the international 76

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welding community in the broadest terms. The award consists of a certificate and a one-year AWS membership. National Meritorious Certificate Award This award recognizes the recipient’s counsel, loyalty, and dedication to AWS affairs, assistance in promoting cordial relations with industry and other organizations, and for contributions of time and effort on behalf of the Society. George E. Willis Award This award is given to an individual

who promoted the advancement of welding internationally by fostering cooperative participation in technology transfer, standards rationalization, and promotion of industrial goodwill. It includes a $2500 honorarium. Honorary Membership Award This award acknowledges eminence in the welding profession, or one who is credited with exceptional accomplishments in the development of the welding art. Honorary Members have full rights of membership.

SECTIONNEWS

Shown at the Long Island Section program are (from left) speaker Joe Kane, Tom Gartland, District 2 Director Harland Thompson, Chair Brian Cassidy, Alex Duschere, Jesse Provler, Ken Messimer, and Pat Nugent.

District 1

Thomas Ferri, director (508) 527-1884 [email protected]

District 2

Harland W. Thompson, director (631) 546-2903 [email protected]

LONG ISLAND JANUARY 12 Speaker: Joe Kane Topic: Discussion of structural and pipe welds from the World Trade Center and other edifices Activity: The program was held in Wantagh, N.Y.

PHILADELPHIA JANUARY 11 Speaker: Jeff Wiswesser Affiliation: Welders Training and Testing Institute Topic: AWS prequalified procedures, qualifying a procedure and the documents involved, qualifying a welder, and how to apply the various welding standards. Activity: The program was held at Villari’s Restaurant in Sicklerville, N.J.

Shown are (from left) District 2 Director Harland Thompson, speaker Jeff Wiswesser, and Philadelphia Section Chair Mike Chomin.

YORK-CENTRAL PA. JANUARY 5 Speaker: Pat Belsole, district sales manager Affiliation: Hypertherm, Inc. Topic: What Hypertherm’s HPR systems can do for you

District 4 Roy C. Lanier, director (252) 321-4285 [email protected]

TIDEWATER

District 3

Michael Wiswesser, director (610) 820-9551 [email protected]

OCTOBER 7 Activity: The Section held its annual Larry O’Bryan Memorial Golf Tournament at Sleepy Hole Golf Course in Suffolk, Va., for 84 participants.

York-Central Pennsylvania Section Chair Jim Henry (left) is shown with speaker Pat Belsole. WELDING JOURNAL

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Florida West Coast members are shown at the January program. OCTOBER 13 Activity: The Tidewater Section members toured the Thomas Jefferson National Accelerator Facility in Newport News, Va. The facility conducts basic atomic research at the quark level. The tour escorts were Michelle Lechman, Will Oren, Debbie Magaldi, Ryan Brodenstein, Mark Wiseman, Bill Hunewill, and Bill Clemens. NOVEMBER 10 Speaker: J. P. Christein, structural engineer Affiliation: Newport News Shipbuilding Topic: Common errors in applying ANSI/ AWS A2.4 welding symbols Activity: This Tidewater Section event was held at Kelley’s Tavern in Hampton, Va.

District 5 Carl Matricardi, director (770) 979-6344 [email protected] Tidewater Section members are shown during their tour of the Thomas Jefferson National Accelerator Facility on October 13.

FLORIDA WEST COAST JANUARY 11 Speaker: Jake Doty, quality inspector Affiliation: GMF Industries, Inc. Topic: Bridge fabrication projects Activity: The program was held at Frontier Steakhouse in Tampa, Fla. Chair Damen Johnson announced the annual Shrimp-ARoo event will be held at a new location. For tickets, contact Johnson at this address: Mark Your Calendar: May 5 Annual Shrimp-A-Roo Yuengling Brewery 11111 N. 30th St., Tampa, Fla. Contact Chair Damen Johnson [email protected]

SOUTH CAROLINA

Shown at the Florida West Coast Section program are Chair Damen Johnson (left) and speaker Jake Doty. 78

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South Carolina Section Chair Gale Mole discussed welder and procedure certifications at the November program.

NOVEMBER 16 Speaker: Chair Gale Mole, NDT manager Affiliation: Soil Consultants, Inc. Topic: Discussion of WPS, PQR, and welder certifications Activity: The program was held at Soil Consultants, Inc., in North Charleston, S.C.

District 6 Kenneth Phy, director (315) 218-5297 [email protected]

District 7 Don Howard, director (814) 269-2895 [email protected]

DAYTON OCTOBER 11 Activity: The Section members met with the welding students at Miami Valley Career Technology Center in Clayton, Ohio. The students served as the instructors demonstrating GMA and SMA welding and automated plasma arc cutting techniques. The attendees had a hands-on opportunity to work with the equipment. NOVEMBER 8 Activity: The Dayton Section members visited the Miami County Fairgrounds in Troy, Ohio, to attend the annual Southern Ohio Forge and Anvil Society (SOFA) demonstrations. The event included some handson activity for the attendees. Leading the program were Steve Roth, a Dayton Section member and a SOFA blacksmith, and Gary Ward, SOFA president. DECEMBER 13 Speaker: Steve Whitney Affiliation: Yaskawa America, Inc., Motoman Robotics, Division Topic: Sensor technology for adaptive robotic welding Activity: Following the talk, the members toured the new Motoman Robotics facility in Miamisburg, Ohio.

District 8 Joe Livesay, director (931) 484-7502, ext. 143 [email protected]

District 9

George Fairbanks Jr., director (225) 473-6362 [email protected]

Shown at the Dayton Section Nov. 8 program are blacksmiths Steve Roth (left) and Gary Ward.

At the Dayton Section Oct. 11 event, the Miami Valley Career Technology Center students demonstrated various fabrication techniques.

Shown at the New Orleans Section program are (from left) Bruce Hallila, Paul Newton, and Chair Aldo Duron. Detroit Section speaker David Harwood (left) is shown with Tom Sparschu. in Section activities. The presenters were Matthew Blackwell, a student at New Orleans Pipe Trades; and Catherine Chifici, studying at South Central Louisiana Technical College. Paul Newton was recognized for taking first place in the Section’s welding competition, instructor level. Inspection Specialists contributed rod ovens as door prizes. The event was held at and catered by Café Hope, in Marrero, La.

District 10

Travis Moore (left) and New Orleans Section Chair Aldo Duron (center) are shown with speaker Rodney Dufour.

Richard A. Harris, director (440) 338-5921 [email protected]

District 11 Robert P. Wilcox, director (734) 721-8272 [email protected]

NEW ORLEANS

DETROIT

JANUARY 17 Speaker: Rodney Dufour Affiliation: Inspection Specialists, Inc. Topic: Inspection trends in the welding industry Activity: Two students presented talks on why students should become more involved

JANUARY 12 Speaker: David Harwood, director nuclear development Affiliation: DTE Energy Topic: Michigan’s electric energy outlook Activity: Gold Member certificates were presented to J. E. Black Jr., Richard Haver,

Student speakers at the New Orleans Section program are Catherine Chifici and Matthew Blackwell. WELDING JOURNAL

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Some of the Detroit Section old timers are (from left) Phil Temple, John McKenzie, Gordon Ebsch, Don Maatz, Dennis Willette, Charles Beach, and Paul D’Angelo.

Greg Siepert, Kansas Section vice chair, is shown holding the banner with the attendees at the students’ night event in October. R. Heinz, Gerald Hoffmeyer, Martin Keasal Jr., G. Ragsdale, and Amos Winsand for 50 years of service to the Society. Life Member certificates were presented to Charles Beach, Rollin Bondar, Paul D’Angelo, Gordon Ebsch, John McKenzie, Robert Shaw Jr., Clyde Slade, and Robert Wilcox for 35 years of service. Silver Member certificates were presented to William Daavettila, Kevin Ede, Ronald Grobbel, Tony Morris, Marvin Owens, Thomas Srigley, Russell Wilcox Jr., and Julian Williams for 25 years of membership.

District 12

Daniel J. Roland, director (715) 735-9341, ext. 6421 [email protected]

District 13

W. Richard Polanin, director (309) 694-5404 [email protected]

District 14 NORTHWEST OHIO

Hutchinson C. C. student Courtney Cauble demonstrates cutting at the Kansas Section event. 80

MARCH 2012

Mark Your Calendar: April 5, 6–9 p.m. 16th Annual Lincoln Motorsports Welding Program Owens Community College Toledo, Ohio Contact Chair Dick West [email protected]

Robert L. Richwine, director (765) 378-5378 [email protected]

District 15 David Lynnes, director (701) 365-0606 [email protected]

Southeast Nebraska Section members are shown during their tour of the Kawasaki Motors facilities in January.

District 16 Dennis Wright, director (913) 782-0635 [email protected]

KANSAS OCTOBER 13 Speaker: Jack Minser, district manager Affiliation; Thermadyne Industries Topic: Plasma and oxyacetylene cutting processes and future applications Activity: This student night event was held at Hutchinson Community College in Hutchinson, Kan. Following the talk, Minser performed various cutting operations using both oxyacetylene and plasma arc technologies.

John Mendoza (far left), AWS 2011 president, is shown at the El Paso holiday event.

SOUTHEAST NEBRASKA JANUARY 17 Activity: Sixty-four Section members toured the Kawasaki Rail Car, Inc., facility in Lincoln, Neb., to study its methods for producing commuter rail cars.

District 17 J. Jones, director (940) 368-3130 [email protected]

Jose “Pep” Gomez (center) is shown with John Bray (left), District 18 director, and John Mendoza, AWS 2011 president, at the El Paso Section program.

NORTH TEXAS JANUARY 17 Speaker: Brad Plank Affiliation: Unified Services of Texas Topic: Failure analysis Activity: The event was held Humperdinck’s in Arlington, Tex.

David Twitty (left) and Mike Jordan received awards at the El Paso Section event.

at

District 18

John Bray, director (281) 997-7273 [email protected]

EL PASO DECEMBER 6 Speaker: John Mendoza, AWS 2011 president Affiliation: Lone Star Welding Topic: A history of AWS CWI certification Activity: On the last trip of his presidency, John Mendoza and District 18 Director John Bray presented Mike Jordan the Sec-

Welding contestants from Industrial High School, Vanderbilt, Tex., pose with instructor, Ardy Tiner (third from right), at the Houston Section-sponsored competition. tion Meritorious Award; Jose ‘Pep’ Gomez the Section Educator and District Director Awards; and David Twitty the District and Section Dalton E. Hamilton Memorial CWI of the Year Awards. This holiday party event was held at Great American Land & Cattle Co. BBQ and Steakhouse in El Paso, Tex.

HOUSTON OCTOBER 14 Activity: Section members and District 18 Director John Bray served as judges at the Gulf Coast Welding Expo and Contest held at Wharton County Jr. College for 71 contestants. Awards were presented for each of seven skill levels. WELDING JOURNAL

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Some of the attendees at the Rio Grande Valley Section program are shown at the students’ night event.

Puget Sound Section past chairs posed at the January 5 program are (from left) front row Jerry Hope, Sid Capouilliez, Shawn McDaniel, and Steve Pollard; back row Charles Daily, Mike Weaver, Chris Sundberg, Ken Johnson, Jay Dwight, Frank Drumm, and Frank Gatto.

District 19 Neil Shannon, director (503) 201-5142 [email protected]

PUGET SOUND NOVEMBER 19 Activity: The Section held its first Robotics Welding Workshop at Everett Community College in Everett, Wash.

A Newport High School student cuts steel at the Puget Sound Robotics Welding Workshop under the watchful eye of instructor Robert White.

RIO GRANDE VALLEY NOVEMBER 9 Speaker: John Bray, District 18 director Affiliation: Affiliated Machinery, president Topic: What AWS membership can mean to you Activity: Students from San Benito High School and the South Texas Community Tech Campus and their parents attended this event. The program was held at South Texas College in McAllen, Tex. 82

MARCH 2012

JANUARY 5 Speaker: Mike Virgilio, NDE structural steel manager Affiliation: Mayes Testing Engineers, Inc. Topic: Using AWS D1.8 Structural Steel Seismic Supplement in the field Activity: This Puget Sound Section honored its past chairs. Attending were Jerry Hope, Sid Capouilliez, Shawn McDaniel, Steve Pollard, Charles Daily, Mike Weaver, Chris Sundberg, Ken Johnson, Jay Dwight, Frank Drumm, and Frank Gatto.

District 20

William A. Komlos, director (801) 560-2353 [email protected]

COLORADO JANUARY 12 Speaker: Adam Chavez, training coordinator Affiliation: Pipefitters Local 208 Topic: Apprenticeship training program Activity: Following the talk, the members toured the Pipefitters Local 208 facility in Denver, Colo. Eric Ortega demonstrated his orbital welding technique. The Local seeks applicants for its apprentice program. Learn more at www.pipe208.com.

IDAHO/MONTANA DECEMBER 9 Activity: The Section members attended the Eastern Idaho Engineering Council’s annual Christmas social at Shiloh Inn in Idaho Falls, Idaho. The event attracts members from various engineering societies, including ANS, ASCE, ASME, AlChE, IEEE, INCOSE, IAS, AWIN, ISA, ISPE, and ACS.

District 21

Nanette Samanich, director (702) 429-5017 [email protected]

Shown at the Idaho/Montana Section event are (from left) Ofilia Tremblay, Jason Wright, Dave Koelsch, and Rae Nims.

Shown at the Puget Sound Section’s Robotics Welding Workshop are Everett Community College Student Chapter members, from left, (front row) Josh Woods, Jason Spiecher, Eric Arnold, Nick Heiner, and Shawn Hiner; (middle row) Steve Pollard, Nina Smith, Eric Daniels, and Stewart Matthews; (back row) John Burton, Bob Jones, Chris Sansbry, Jason Heard, Robert White, and Jerry Hop.

Shown during the Colorado Section tour are Chair John Steele, speaker Adam Chavez, and pipe welder Eric Ortega.

Shown at the Los Angeles-Inland Empire Section meeting are (from left) Tim Serviss; Chair George Rolla; Mariana Ludmer; Robert Doiron; Kenneth Reid; Gene Lawson, a past AWS president; Che Chancy; and Nanette Samanich, District 21 director.

Chris Chwala is shown with Liisa Pine, San Francisco Section co-chair.

Affiliation: Lone Star Welding Topic: The importance of welder certification here and abroad Activity: Gene Lawson, treasurer and a past AWS president, attended the program. DECEMBER 29 Activity: The Los Angeles/Inland Empire Section board members met to discuss Section activities for the coming year.

District 22 Dale Flood, director (916) 288-6100, ext. 172 [email protected]

Liisa Pine, San Francisco Section co-chair, presents a speaker gift to Mark Bell.

LOS ANGELES/ INLAND EMPIRE SEPTEMBER 14 Speaker: John Mendoza, AWS president 2011

SAN FRANCISCO JANUARY 4 Speaker: Mark Bell Affiliation: Bell Metallurgy Topic: Welding on in-service pipelines Activity: The program, held at Spenger’s Restaurant in Berkeley, Calif., attracted 34 members. Member Chris Chwala, president of Ryco Steel Products, Inc., donated $1000 to the Section. Elizabeth Moore has

Shown at the Los Angeles/Inland Empire Section program are (from left) Vice Chair Robert Doiron, AWS 2011 President John Mendoza, and Gene Lawson, a past AWS president.

resigned as Section chair. Liisa Pine and Sharon Jones will serve as co-chairs for the remainder of Moore’s term. WELDING JOURNAL

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Guide to AWS Services 550 NW LeJeune Rd., Miami, FL 33126; (800/305) 443-9353; FAX (305) 443-7559; www.aws.org Staff extensions are shown in parentheses.

AWS PRESIDENT

INTERNATIONAL SALES

William A. Rice [email protected] 1411 Connell Rd. Charleston, WV 25314

Managing Director, Global Exposition Sales Joe [email protected] . . . . . . . . . . . . . . . .(297)

ADMINISTRATION Executive Director Ray W. Shook.. [email protected] . . . . . . . . . .(210) Sr. Associate Executive Director Cassie R. Burrell.. [email protected] . . . . . .(253) Sr. Associate Executive Director Jeff Weber.. [email protected] . . . . . . . . . . . . .(246)

Corporate Director, International Sales Jeff P. [email protected] . . . . . . .(233) Oversees international business activities involving certification, publication, and membership.

PUBLICATION SERVICES Department Information . . . . . . . . . . . . . . . . .(275) Managing Director Andrew Cullison.. [email protected] . . . . . .(249)

Chief Financial Officer Gesana Villegas.. [email protected] . . . . . .(252)

Welding Journal Publisher Andrew Cullison.. [email protected] . . . . . .(249)

Executive Assistant for Board Services Gricelda Manalich.. [email protected] . . . . .(294)

Editor Mary Ruth Johnsen.. [email protected] . .(238)

Administrative Services

National Sales Director Rob Saltzstein.. [email protected] . . . . . . . . . . .(243)

Managing Director Jim Lankford.. [email protected] . . . . . . . . . . . . .(214) IT Network Director Armando [email protected] . .(296)

Society and Section News Editor Howard [email protected] . .(244)

TECHNICAL SERVICES Department Information . . . . . . . . . . . . . . . . .(340) Managing Director Andrew R. Davis.. [email protected] . . . . . . .(466) International Standards Activities, American Council of the International Institute of Welding (IIW) Director, National Standards Activities Annette Alonso.. [email protected] . . . . . . .(299) Manager, Safety and Health Stephen P. Hedrick.. [email protected] . . . . . .(305) Metric Practice, Safety and Health, Joining of Plastics and Composites, Welding Iron Castings, Welding in Sanitary Applications, Personnel and Facilities Qualification Senior Manager, Technical Publications Rosalinda O’Neill.. [email protected] . . . . . . .(451) AWS publishes about 200 documents widely used throughout the welding industry. Senior Staff Engineer Rakesh Gupta.. [email protected] . . . . . . . . . .(301) Filler Metals and Allied Materials, International Filler Metals, UNS Numbers Assignment, Arc Welding and Cutting Processes

Director Hidail Nuñ[email protected] . . . . . . . . . . . .(287)

Welding Handbook Editor Annette O’Brien.. [email protected] . . . . . . .(303)

Staff Engineers/Standards Program Managers Efram Abrams.. [email protected] . . . . . . . .(307) Thermal Spray, Automotive Resistance Welding, Oxyfuel Gas Welding and Cutting

Director of IT Operations Natalia [email protected] . . . . . . . . . .(245)

MARKETING COMMUNICATIONS

Human Resources

Director Ross Hancock.. [email protected] . . . . . . .(226)

Stephen Borrero.. [email protected] . . . . . .(334) Brazing and Soldering, Brazing Filler Metals and Fluxes, Brazing Handbook, Soldering Handbook, Railroad Welding, Definitions and Symbols

Director, Compensation and Benefits Luisa Hernandez.. [email protected] . . . . . . . . .(266) Director, Human Resources Dora A. Shade.. [email protected] . . . . . . . . .(235)

International Institute of Welding

Public Relations Manager Cindy [email protected] . . . . . . . . . . . .(416) Webmaster Jose [email protected] . . . . . . . . .(456)

Senior Coordinator Sissibeth Lopez . . [email protected] . . . . . . . . .(319) Liaison services with other national and international societies and standards organizations.

Section Web Editor Henry [email protected] . . . . . . . . .(452)

GOVERNMENT LIAISON SERVICES

Department Information . . . . . . . . . . . . . . . . .(480) Sr. Associate Executive Director Cassie R. Burrell.. [email protected] . . . . . .(253)

Hugh K. Webster . . . . . . . . [email protected] Webster, Chamberlain & Bean, Washington, D.C., (202) 785-9500; FAX (202) 835-0243. Monitors federal issues of importance to the industry.

CONVENTION and EXPOSITIONS Jeff Weber.. [email protected] . . . . . . . . . . . . .(246) Director, Convention and Meeting Services Selvis [email protected] . . . . . .(239)

ITSA — International Thermal Spray Association Senior Manager and Editor Kathy [email protected] . . .(232)

RWMA — Resistance Welding Manufacturing Alliance Manager Susan Hopkins.. [email protected] . . . . . . . . .(295)

WEMCO — Welding Equipment Manufacturers Committee Manager Natalie Tapley.. [email protected] . . . . . . . . . .(444)

Brazing and Soldering Manufacturers’ Committee Jeff Weber.. [email protected] . . . . . . . . . . . . .(246)

GAWDA — Gases and Welding Distributors Association Executive Director John Ospina.. [email protected] . . . . . . . . . .(462) Operations Manager Natasha Alexis.. [email protected] . . . . . . . . .(401)

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MEMBER SERVICES

Director Rhenda A. Kenny... [email protected] . . . . . .(260) Serves as a liaison between Section members and AWS headquarters.

CERTIFICATION SERVICES Department Information . . . . . . . . . . . . . . . . .(273) Managing Director John L. Gayler.. [email protected] . . . . . . . . . .(472) Oversees all certification activities including all international certification programs. Director, Certification Operations Terry [email protected] . . . . . . . . . . . . .(470) Oversees application processing, renewals, and exam scoring. Director, Certification Programs Linda [email protected] . . . . . . .(298) Oversees the development of new certification programs, as well as AWS-Accredited Test Facilities, and AWS Certified Welding Fabricators.

EDUCATION SERVICES Director, Operations Martica Ventura.. [email protected] . . . . . .(224) Director, Education Development David Hernandez.. [email protected] . . .(219)

AWS AWARDS, FELLOWS, COUNSELORS Senior Manager Wendy S. Reeve.. [email protected] . . . . . . . .(293) Coordinates AWS awards, Fellow and Counselor nominees.

Alex Diaz.. [email protected] . . . . . . . . . . . . . . .(304) Welding Qualification, Sheet Metal Welding, Aircraft and Aerospace, Joining of Metals and Alloys Brian McGrath . [email protected] . . . . . . .(311) Methods of Inspection, Mechanical Testing of Welds, Welding in Marine Construction, Piping and Tubing, Friction Welding, Robotics Welding, High-Energy Beam Welding Matthew [email protected] . . . . . . .(215) Structural Welding, Machinery and Equipment Notes: Official interpretations of AWS standards may be obtained only by sending a request in writing to Andrew R. Davis, managing director, Technical Services, [email protected]. Oral opinions on AWS standards may be rendered, however, oral opinions do not constitute official or unofficial opinions or interpretations of AWS. In addition, oral opinions are informal and should not be used as a substitute for an official interpretation.

AWS FOUNDATION, INC. www.aws.org/w/a/foundation General Information (800/305) 443-9353, ext. 212, [email protected] Chairman, Board of Trustees Gerald D. Uttrachi Executive Director, Foundation Sam Gentry.. [email protected]. . . . . . . . . . . . . . . (331)

Corporate Director, Workforce Development Monica Pfarr.. [email protected]. . . . . . . . . . . . . . . . (461) The AWS Foundation is a not-for-profit corporation established to provide support for the educational and scientific endeavors of the American Welding Society. Promote the Foundation’s work with your financial support. Call for (800) 443-9353information.

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Jefferson’s Welding Encyclopedia (CD-ROM only) Design & Planning Manual for Cost-Effective Welding Welding Metallurgy Welding Handbook (9th Ed., Vol. 4) Welding Handbook (9th Ed., Vol. 3) Welding Handbook (9th Ed., Vol. 2) Welding Handbook (9th Ed., Vol. 1) For more book choices visit www.aws.org/membership

Account # Date Amount †Two-year Individual Membership Special Offer: applies only to new AWS Individual Members. ††Discount Publication Offer: applies only to new AWS Individual Members. Select one of the seven listed publications for an additional $35; NOTE: a $50 shipping charge applies to members outside of the U.S., add $85 ($35 for book selection and $50 for international shipping); Multi-Year Discount: First year is $80, each additional year is $75. No limit on years (not available to Student Members). †††Student Member: Any individual who attends a recognized college, university, technical, vocational school or high school is eligible. This membership includes the Welding Journal magazine. Student Memberships do not include a discounted publication. ††††International hard copy Welding Journal option: applies only to International AWS Welder Members (excludes Canada and Mexico). Digitized delivery of WJ is standard

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Ferrous metals Aluminum Nonferrous metals except aluminum Advanced materials/Intermetallics Ceramics High energy beam processes Arc welding Brazing and soldering Resistance welding Thermal spray Cutting NDT Safety and health Bending and shearing Roll forming Stamping and punching Aerospace Automotive Machinery Marine Piping and tubing Pressure vessels and tanks Sheet metal Structures Other Automation Robotics Computerization of Welding

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PERSONNEL OKI Bering Taps COO OKI Bering, Cincinnati, Ohio, a wholesaler of welding, safety, and industrial supplies, has promoted Roch Monahan to chief operating officer. Monahan has assumed the duties of Byron Crampton who retired at the end of 2011. Monahan, who has an extensive background in the welding industry, will Roch Monahan continue to hold his previous position of vice president of sales.

of Panasonic Factory Solutions Co. of America, based in Rolling Meadows, Ill. Pandit, who succeeds Gebhardt in the post, previously served as director of solutions within the same company.

Two ESAB VPs Appointed Colfax Corp., Fulton, Md., a supplier of gas- and fluid-handling and fabrication technology, has named Kenneth D. Konopa vice president of marketing for ESAB and Vincent Northfield vice president of global manufacturing for ESAB. Konopa previously served as president of Danaher Corp.’s Fluke Industrial and Ormco divisions. Northfield most recently was executive vice president of global operations for Teleflex Medical.

Two Presidents Named at Panasonic Corp.

Airgas Names Executives

Panasonic Corp. of North America, Secaucus, N.J., has named Tom Gebhardt president of Panasonic Automotive Systems Co. of America, based in Peachtree City, Ga.; and M. Faisal Pandit president

Airgas, Inc., Radnor, Pa., has named R. Jay Worley vice president — strategic pricing. J. Barrett Strzelec, director of investor relations for Airgas, Inc., will assume leadership of the investor relations function. Worley, with the company since 1993, pre-

viously served as vice president — communications and investor relations since 2008.

President Named at LA-CO® Industries LA-CO® Industries, Inc./Markal Co., Elk Grove Village, Ill., has appointed George Bowman president, succeeding John Hardin who has retired. Prior to joining the company, Bowman was George Bowman president of Enerpac at Actuant Corp. and worked at General Electric Industrial Systems for 11 years in various sales and engineering leadership positions.

Noble Gas Appoints Sales Director Noble Gas Solutions, Albany, N.Y., has appointed Patrick O’Donnell director of sales. O’Donnell previously worked six years for General Electric Co.

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Kaman Industrial Technologies Corp., Bloomfield, Conn., has appointed Kyle Ahlfinger area vice president of its Minarik division; and Gary Yingling director and general manager, shops and services. Previously, Ahlfinger was corporate vice president and chief marketing officer at Flowserve Corp. Prior to joining the company, Yingling worked for Stanadyne Corp. as director, global accounts, and at Molex, Inc., as director and general manager of its industrial communications and software business. Kaman is a supplier of automation, material-handling, motioncontrol, bearings, mechanical power transmissions, and other industrial parts.

MARCH 2012

The Robotic Industries Assn. (RIA), Ann Arbor, Mich., has named Catherine Morris chair of the board. She becomes

the 20th chair since the RIA was founded in 1974, and is the first woman to serve in the position. Morris is senior account manager for ATI Industrial Automation.

American Torch Tip Hires Account Executive

engineers and technologists for the advancement of manufacturing education.

Wolf Robotics Names Manager for Brazil

American Torch Tip, Bradenton, Fla., has appointed Tony Ragle regional account executive for Illinois, Indiana, Kentucky, and Tennessee. Ragle brings more than 35 years of experience in semiautomatic and robotic welding applications.

Wolf Robotics, Fort Collins, Colo., has hired Marcio Mininel as regional manager for all of Brazil, based in Piracicaba. Mininel has more than a decade of experience in programming and robotic welding implementation. He most recently worked as a process engineer for Caterpillar Brazil.

ARC Specialties Hires Asst. Project Manager

Obituary

Hoang Nguyen

ARC Specialties, Inc., Houston, Tex., a manufacturer of automated and robotic welding systems, has hired Hoang Nguyen as assistant project manager. Nguyen has interned with Hitachi GST, Applied Materials, and Neptec Optical Solutions.

Sancap Abrasives Names Account Executive Sancap Abrasives, Alliance, Ohio, has appointed James Moran regional sales manager to work with its national sales representatives and distribution network. Moran brings 30 years of industrial and distribution expertise to the post.

SME Names President and Education Board Execs The Society of Manufacturing Engineers (SME), Dearborn, Mich., has elected LaRoux K. Gillespie president for 2012. Gillespie is a metal finishing consultant and a retired Kansas City Honeywell quality leader. The SME Education Foundation has named its 2012 board of directors representing business, industry, and academia. Appointed were Glen H. Pearson, president; Brian A. Ruestow, vice president and secretary; Peter F. Mackie, treasurer and chair of finance; and Edward M. Swallow, assistant treasurer and vice chair of finance. Pearson was with Eastman Kodak Co. (ret.); Ruestow is with F. W. Roberts Mfg. Co., Inc.; Mackie is with Wells Fargo Advisors LLC; and Swallow is with Northrop Grumman Information Systems. The mission of the foundation is to inspire, support, and prepare the next generation of manufacturing

William ʻBillʼ H. Kielhorn William “Bill” Kielhorn, 80, died Jan. 6 at his home in Longview, Tex. Recently named an AWS Fellow, he is remembered as the LeTourneau University professor who never missed teaching a class for 45 years. He presented his final class using a laptop from a hospital bed. Kielhorn was born in Oxford, Wis., then lived in Chicago and North Carolina before enlisting in the U.S. Air Force in 1951 for four years. In 1956, he enrolled in LeTourneau TechWilliam “Bill” Kielhorn nical Institute where he graduated with a degree in welding engineering in 1959. He received his master’s degree from the University of Wisconsin, Madison. Kielhorn served as a welding engineer at Worthington Pump in Harrison, N.J., from 1959 to 1966 then returned to LeTourneau College to teach in the welding department. He served the American Welding Society in many capacities with the East Texas Section and as District 17 director for eight years. He was a past member of the AWS Technical Activities and National Scholarship Committees, and chapter chair for Aluminum Welding in the Welding Handbook, 8th edition, Vol. 3, and the Survey of Welding Processes chapter of the 9th edition, Vol. 1. Kielhorn is survived by his wife, Betty; two daughters; and five grandchildren. The family requests donations be made to the William H. Kielhorn Scholarship Fund at LeTourneau University, PO Box 7001, Longview, TX 75607; or made online at www.letu.edu. For info go to www.aws.org/ad-index

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THE AMERICAN WELDER How to Pick the Right-Sized Welding Cable Here are a formula and tables that will help you to choose a safe-sized cable every time BY AUGUST F. MANZ What size welding cable do you need to be safe when you are using XX amperes and are about YY feet from the power supply? Most welders know that the use of the wrong cable size can lead to cable overheating, insulation failure, electric shock, and even fires. The wrong size can even affect the welding condition.

Picking a Safe Cable Size To answer the question above, you need to know the welding current and the distance from the power supply. The safe American Wire Gauge (AWG) size is based on a 4-V cable loss, due to the welding current flowing through the cable resistance. (Note: Years ago, it was agreed that a 4-V cable loss, due to welding current, would be acceptable. A 4-V drop does not have too much effect on the arc system or the system efficiency.) Table 1 shows that at 250 A and 150 ft from the power supply, the correct size is a 4/0 AWG cable, which is the same as the #0000 AWG in Table 2.

Another Method You can also pick a safe cable size by using the formula below, and Table 2, for copper cables. First, calculate the safe circular mil size needed. Circular mil (CM) is an engineering measure of the cable cross-section area. CM = 10.37 A (total cable length, ft)/4 V Now, use the calculated CM value and the AWG sizes in Table 2 to select a cable (the 10.37 value is only good for copper cables). Always pick an AWG cable size with a CM Table 1 — Recommended Sizes of Copper Welding Leads Amps 50 100 150 200 250 300 350 400 450 550 600

AUGUST F. MANZ is a Fellow of the American Welding Society.

2 2 2 2 1 1/0 1/0 2/0 3/0 3/0

75 2 2 1 1/0 2/0 3/0 3/0 4/0 4/0

100 2 1 1/0 2/0 3/0 4/0 4/0

Distance in Feet from Welding Machine 125 150 175 200 225 250 300 2 1/0 2/0 3/0 4/0

1 2/0 3/0 4/0

1/0 3/0 4/0

1/0 3/0 4/0

2/0 4/0

2/0 4/0

3/0

350

400

4/0

4/0

*Based on direct current and 4-V drop. Double the distance for total length.

WELDING JOURNAL

91

THE AMERICAN WELDER Table 2 — Wire Table, Standard Annealed Copper American Wire Gauge

Gauge No.

Dia. in Mils at 20°C

0000 000 00 0 1 2 3 4

460.0 409.6 364.8 324.9 289.3 257.6 229.4 204.3

Cross Section 20°C Circular Square Mils Inch 211,600 167,800 133,100 105,500 83,690 66,370 52,640 41,740

value larger than the calculated value. Do not pick an AWG size smaller than #2 because of needed mechanical strength. The following is an example CM calculation: To determine the safe AWG size cable needed for 250 A and a total cable length of 300 ft [150 ft × 2 (from the power supply to the arc and return)], you use the following formula: CM = 10.37 (250)(300)/4 = 194,438 cm

0.1662 0.1318 0.1045 0.08289 0.06573 0.05213 0.04134 0.03278

Pounds 1000 ft

0°C (32°F)

Ohms per 1000 ft 20°C (68°F)

50°C (122°F)

640.5 507.9 402.8 319.5 253.3 200.9 159.3 126.4

0.04516 0.05695 0.07181 0.09055 0.1142 0.1440 0.1816 0.2289

0.04901 0.06180 0.07793 0.09827 0.1239 0.1563 0.1970 0.2485

0.05479 0.06909 0.08712 0.1099 0.1385 0.1747 0.2203 0.2778

In Table 2, the next larger CM is 211,600 cm, for #0000 AWG cable. This is the same 4/0 size you found in Table 1. The actual voltage drop in the cable can be calculated as follows: From Table 2, for #0000 AWG, at 20°C (the estimated room temperature) there are 0.04901 ohms per 1000 ft. Using Ohm’s Law as follows: Volts = (ohms) (amperes) = (0.04901 ohms/1000 ft)(300 ft)(250 A) = 3.68 V

The calculated 3.68-V loss is smaller than the acceptable 4-V loss agreed upon, and is okay. Calculations like this were used to generate the data in Table 1.

The Bottom Line With the tables and information in this article, you can choose a safe cable size every time.◆

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THE AMERICAN WELDER WELDING PROJECT Welded Benches for Fun and Fund-Raising BY HOWARD WOODWARD

The whimsical garden bench featuring a black cat theme (Fig. 1) was built by Rufino Caniz, a Guatemalan, as a welding project during his studies as a visiting professor at Illinois Central College.

Caniz studied welding under Eric Ockerhausen, Peoria Section treasurer and advisor to the Section’s Student Chapter, who used the funds raised from selling these benches to help finance a pet project of his based in Guatemala. Ockerhausen explained that he and Caniz would spend 13 days in Guatemala building a cost-effective system he designed to dry coffee beans using solar energy and materials found locally. The project, if successful, would benefit the local economy. As for designing the benches, Ockerhausen explained, “You don’t really need measurements because each type of bench should be different. I chose a cat but another student did a rhino, because that was his animal of choice.” For this project, the bill of materials included six, four-ft-long boards 1 in. by 6 in.; 24 carriage bolts; four sections of angle iron 4 ft long; plus eight pieces of angle iron cut to fit (12 ft total). The cat’s dimensions are roughly 28 in. long, by 18 in. high, with a 17-in.-

HOWARD WOODWARD ([email protected]) is associate editor of the Welding Journal.

Fig. 1 — Attention-getting bench designs are easy to make and limited only by the welder’s imagination. This cat motif was inspired by a small cast-iron feline. Its outline was enlarged by projecting its shadow onto a piece of paper using an ordinary flashlight. The shadow was traced then transferred to sturdier material to make the pattern for cutting the steel “cats.”

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THE AMERICAN WELDER WELDING PROJECT

Fig. 2 — Rear view of the bench showing the angle iron supports and carriage bolts.

Fig. 3 — Ockerhausen sprays black paint on his soda-can-based solar heating system to enhance its efficiency. The heater is part of a coffee bean drying system he designed and recently installed in Guatemala.

long tail. The whiskers are silicone held on with a dab of silicone caulk. Ockerhausen stated, “The best way to design a bench is to just sit on a bench. If it is comfortable, measure it and make yours similar to that one. Most of the bench seats are about 17 to 18 in. off the ground, and they can be straight or at just a slight tilt. The back rest is always at a little angle for comfort.” The first steps are to decide on an animal design, how big to make it, and how to transfer that design into a piece of steel heavy enough to support a person’s weight. “We used 3⁄8-in. steel,” Ockerhausen said, “and since we did not have a big sheet of it, we welded a couple of pieces together to make a piece large enough to work with. We just cut the metal, welded it together, then ground it smooth. That can keep your cost down. “As you can see, on the backside of the bench we used angle irons to support the seat and the back rest — Fig. 2. Since we used redwood salvaged from an old wooden pallet, we had to add the extra metal supports to make the bench strong enough to hold a person. If you use 2 × 4 treated lumber, the wood bolted to the bench pieces should be strong enough to support

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the bench and the people sitting on it.” Note that a metal plate is welded between the cat’s feet to distribute the weight and keep the bench stable on soft ground. “Anything that spreads out the weight,” Ockerhausen said, “will work just fine. On other benches, we used 3-in.diameter metal circles to spread the weight. “For the (animal) design you can use anything you like. Be creative and have fun with it. If you can draw, you can just trace out the full-sized design. “For the cat bench, I used a small cast iron cat as the model. I mounted large pieces of white paper on a wall, then used a flashlight to cast a shadow of the model onto the paper. Once the shadow size was as big as I thought it needed to be, I traced the shadow onto the paper. Then, I cut that design out and copied it onto a heavier material to use as the pattern for making future cats from steel.” Ockerhausen noted, you do have to be a little creative to turn a design into something practical. That is the fun part. “If it does not work out just right the first time, grind off the weld and make the adjustments. That is a good thing about welding.” Caniz and Ockerhausen left for

Guatemala in early January to start their project. They built a solar-powered coffee bean drying system constructed from empty soda cans (Fig. 3), a passive solar water heater, and a wall constructed from plastic soda bottles filled with sand for the insulating “bricks.” They used solar light tubes under the tin roof to provide light during the day. Ockerhausen noted this is a continuing project that needs additional support. He seeks donations to help fund a wasteoil burner for drying coffee and to develop a more efficient method to pump lake water uphill. Also, they are seeking a donor to provide an engine-driven generator to provide electricity during power outages. Ockerhausen’s broad plan is to eventually develop a market in his area for the Guatemalan coffee. Illinois Central College is hopeful this project may provide a study-abroad program offering students an opportunity to travel to this area of Guatemala to learn while working on creative projects. His mind still toying with new ideas for benches, Ockerhausen mused, “I was just thinking of a giraffe design, or maybe for Florida I could try to build a sailfish bench.”♦

THE AMERICAN WELDER LEARNING TRACK Pipe Fitters Local Offers Comprehensive Training Options BY HOWARD WOODWARD ([email protected]) is associate editor of the Welding Journal.

Front row, from left, are Pipe Fitters 597 welding instructors Mike Galfano, Peter Larou, Rich Lopez, Bill Enright, Marc Randulich, Dave Hintz, Mike Pelegrino, Rick Hobson, Glen Burch, and Tyler Johnson. Not pictured is instructor Mark Duewerth. Standing are the Tuesday’s class of 1st-, 2nd-, and 4thyear building trades apprentices, who total about 90 welders each day.

Students at Pipe Fitters 597 benefit from experienced instructors, many with CWI credentials, small class sizes, and well-equipped training facilities

Welding instructor Mike Pelegrino is pleased with the success of the welder apprentice classes at Pipe Fitters’ Training Center Local Union 597 in Mokena, Ill., a village just southwest of Chicago. 96

MARCH 2012

The Training Facility The training facility, opened in May 2005, is big and the number of training staff is impressive. The 198,000-sq-ft facil-

ity’s welding lab features 116 welding booths, two computer rooms with 20 workstations in each, two coupon-cutting machines using oxyfuel cuts and machine bevels, an overhead crane, a lecture hall

THE AMERICAN WELDER LEARNING TRACK fitted with wireless laptops, advanced audio/visual capabilities, and seating for 250. The Training Schedules Training work is performed both indoors and outdoors to simulate actual onthe-job working conditions. At one time, there may be as many as 800 apprentices studying pipe fitter courses. The classes are also offered five nights a week, from 5 to 8 p.m., to accommodate apprentices and journeypersons. The Welding Staff Pelegrino said, “We have approximately 30 part-time welding instructors during the evening classes. They work in the field for contractors during the day, then come here to teach for another three hours. “The daytime teaching staff are all pipe fitters who continue to receive extensive training on a yearly basis to update their skills.” The daytime staff (see lead photo) includes Certified Welding Inspector (CWI) and Certified Welding Educator (CWE) Mike Pelegrino, an apprentice welding instructor for SMAW, GTAW, GMAW, FCAW; Mike Galfano, apprentice basic pipe fitting, OSHA regulations, and rigging instructor; CWI Peter Larou, downhill pipe welding instructor; Rich Lopez, Journeyperson welding instructor for SMAW, GTAW, GMAW, and FCAW; CWI and CWE Bill Enright, apprentice drafting, history and heritage, and CWI prep instructor for Journeypersons; CWI Marc Randulich, apprentice welding instructor for SMAW, GTAW, GMAW, FCAW; CWI and CWE Dave Hintz, welding coordinator and certification apprentices and Journeymen; CWI Rick Hobson, apprentice welding instructor for SMAW, GTAW, GMAW, FCAW; CWI Glen Burch, hybrid welding instructor; CWI Tyler Johnson, downhill pipe welding instructor; and Mark Duewerth, apprentice math and layout instructor. “A big feature,” Pelegrino said, “is while welding class sizes vary, in most cases there is a 14:1 student-instructor ratio, giving each student adequate personal instruction.” He is particularly pleased that four of his second-year welding students participated in the 2011 FABTECH Professional Welding Contest in Chicago and earned the first-, fourth-, fifth-, and twelfth-place honors.

CWI Mike Pelegrino inspects a student’s weld

Attendance Requirements Unlike most welding training facilities, the Pipe Fitters’ apprentice program is essentially a ‘scholarship,’ with zero cost to the apprentice. The fees are funded by the membership of the Local Union. However, students must continually demonstrate learning skills and the ability to pass the stringent ASME Section IX code requirements or they may be dropped from further studies. “Our welding course is set up or bro-

ken down into years,” Pelegrino said. For example, the first-year (six months) apprentices learn horizontal Tjoint multipass welding of 3⁄8-in. equal leg (2F), per visual requirements of ASME Section IX, and vertical T-joint multipass welding of 3⁄8-in. equal leg (3F), per visual requirements of ASME Section IX. The second six (6) months provides training on welding 6-in. Schedule 80 pipe in the 1G position, per visual requirements of ASME Section IX and requires passing of radiographic inspection.

Apprentices practice on welding large-diameter pipe.

WELDING JOURNAL

97

THE AMERICAN WELDER LEARNING TRACK process follows the same progression with each position being taught. Once the apprentice tests again on carbon-steel pipe in the 6G position on 2-in. Schedule 80 (the UA 15), then they will move onto using stainless steel filler metals. The procedure continues for each type of different filler metals and then an X-ray test for qualifying them.” The fourth-year apprentices study advanced SMA, GTA, and GMA/FCA welding processes. The facility also offers apprentice training in the building trades including an industrial rigging certification course. Visit the Union’s Web site, or call or write for more information.◆

Apprentices test their skills cutting large-diameter pipe outdoors to simulate real-life working conditions. “Once the apprentice passes the required tests set forth by Local 597,” Pelegrino said, “they may proceed to the GTAW process. Please note that the apprentice can proceed at a faster pace and

have his requirements met prior to his or her indenture dates. “The GTAW process, introduced in the third year, is taught on 4- and also 2-in. pipe with variations as needed. This

Pipe Fitters’ Training Center Local Union 597 10850 W. 187th St. Mokena, IL 60448 Phone: (708) 326-9240 FAX: (708) 326-9241 E-mail: [email protected] www.pftf597.org

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THE AMERICAN WELDER FACT SHEET SMAW Electrode Orientation

Fig. 1 — Orientation of the electrode. In shielded metal arc welding (SMAW), the orientation of the electrode in relation to the workpiece and the weld groove controls the direction and lo-

cation of the arc and is an important factor in weld quality. Improper positioning of the electrode can result in slag entrapment, porosity, and weld undercut.

Proper orientation in the joint depends on the type and size of electrode, welding position, and joint geometry. A skilled welder automatically evaluates these factors when deciding the orientation to be used for a specific joint. The positioning of the electrode relative to the joint and the workpiece is described by the travel angle and work angle. The term travel angle denotes the angle (less than 90 deg) between the electrode axis and a line perpendicular to the weld axis, in a plane determined by the electrode axis and weld axis. The term work angle denotes the angle (less than 90 deg) between a line perpendicular to the major workpiece surface and a plane determined by the electrode axis and the weld axis. When the electrode is pointed in the direction of welding, the technique is termed forehand welding. The travel angle is then known as the push angle. When the electrode is pointed in the opposite direction to that of welding, the technique is termed backhand welding. The travel angle in backhand welding is called the drag angle. These angles are shown in Fig. 1. Correct placement of the electrode helps to achieve control of the weld pool, attain the desired penetration, and ensure complete fusion to the base plate. Typical electrode orientation and welding technique for groove and fillet welds for use on carbon steel with carbon steel electrodes are listed in Table 1. These values may be different for other electrodes and materials. A large travel angle may cause a convex, poorly shaped bead with inadequate penetration, whereas a small travel angle may cause slag entrapment. A large work angle can cause undercutting, while a small work angle can result in incomplete fusion.♦

Table 1 — Typical Shielded Metal Arc Electrode Positioning and Welding Techniques for Carbon Steel Electrodes Joint Type

Welding Position

Work Angle (deg)

Travel Angle (deg)

Welding Techniques

Groove Groove Groove Groove Fillet Fillet Fillet

Flat Horizontal Uphill Overhead Horizontal Uphill Overhead

90 80–100 90 90 45 35–55 30–45

5–10(a) 5–10 5–10 5–10 5–10(a) 5–10 5–10

Backhand Backhand Forehand Backhand Backhand Forehand Backhand

(a) Travel angle may be 10 to 30 deg for electrodes with heavy iron powder coverings.

100 MARCH 2012

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NEWS OF THE INDUSTRY — continued from page 11

The hope of the program established at Pulaski High School, assisted with training services and supplies from Caterpillar and Lincoln, is to decrease the skills gap many businesses experience.

if the company would assist with its current welding program. Dale Gilbertson, a weld training supervisor, coordinated the effort with school administrators. Caterpillar representatives then spent the summer working with administrators to identify needs, provided students with a manufacturing process introduction, and guided facility tours at its South Milwaukee campus. The company also assisted developing curriculum to the school’s welding instructors and put them through the Caterpillar 101 welding course. In addition, employees Willy Love and Jose Ramirez provide on-site instruction, visiting the classroom once a week, and will continue to do so until the end of each semester. Along with Lincoln Electric, the company supplied welding consumables, personal protective equipment, and steel to support the weld program. Currently, 40 participants are enrolled.

Industry Notes • First Coast Technical College has established an evening welding program on Mondays, Tuesdays, and Wednesdays. Located in Palatka’s Industrial BargePort facility, Florida, the college’s classroom/lab features 35 stations. Classes are set to begin March 19 and several prerequisites apply, so early application is encouraged. For more details, e-mail [email protected]. • MassDevelopment issued a $4 million tax-exempt bond, purchased by TD Bank, on behalf of Bomco, Inc., Gloucester, Mass., a producer of sheet metal fabrications for jet engines and turbines. Proceeds will be used for equipment and to build an 18,000-sq-ft manufacturing facility on its current property. • Praxair Distribution, Inc., Danbury, Conn., executed an agreement to acquire Texas Welders Supply Co., the largest independent gas and welding products distributor in the greater Houston area with 130 employees. • Spoon River College, Illinois, is bringing back its welding program in the spring 2012 semester. The six-credit welding operator certificate is comprised of three courses — engineering graphics, introduction to welding, and gas metal arc welding. 104 MARCH 2012

• MICOR® Industries, Inc., Decatur, Ala., obtained its qualifications and certifications to weld per ASME Section IX, on 6AL-4V (Grade 5) titanium. • Stork Materials Technology, Amsterdam, The Netherlands, a materials and product qualification testing provider, officially changed its name to Element Materials Technology. • The R&D team at Solar Atmospheres developed a new hot zone design concept to reduce vacuum furnace power losses. To test the design, it is rebuilding a mid-size production vacuum furnace hot zone in its headquarters, Souderton, Pa. • Blackland Group added to its aerospace component manufacturing platform, Kessington Holdings, LP, acquiring Prikos & Becker Tool Co., Skokie, Ill., a specializer in intricate assemblies requiring metal fabrications. • Werts Welding & Tank Service, Inc., opened a new branch in Billings, Mont., to serve its western and northwestern user base by reducing tank trailer parts and equipment delivery times. • The umbrella trade association for the Robotic Industries Association, AIA, and the Motion Control Association changed its name from the Automation Technologies Council to the Association for Advancing Automation (A3). • Northwest Pipe Co. plans to expand its Saginaw, Tex., manufacturing facility to serve the area’s needs of anticipated large water projects, including a mill expansion that will increase the diameter and thickness ranges of spiral welded steel pipe. • Holston Gases, Knoxville, Tenn., completed acquiring Cumberland Welding Supply Co., Somerset, Ky. Operations will now be consolidated with Holston’s operation in Somerset. • Red-D-Arc Welderentals has partnered with Key Plant Automation Ltd., Liverpool, UK, to be its exclusive global distributor of Key Plant weld-positioning/automation products. • Noble Gas Solutions, Albany, N.Y., donated $5000 to the Rensselaer Boys & Girls Club. In a recent Times Union article, it was noted the club is “in dire straits,” and shuttering its doors would put more than 120 children out on the street every day.◆

Call for Papers 17th JOM/IIW Int’l Conf. and Expo on the Joining of Materials May 5–8, 2013, Helsingør, Denmark Papers are sought on all aspects of developments in joining and material technology. Topics of most interest include recent developments in welding, soldering, and brazing. Advances in materials, metallurgy, and weldability. Mathematical modeling and simulation. Process monitoring, sensors, and control. Structural integrity and inspection. Applications with relevance to industry needs, automotive, oil, gas, and power generation. Weld quality structural properties, and environmental considerations. Education, training, and qualification and certification of welding personnel. Each paper will be peer reviewed for technical accuracy. The deadline for submitting the title and a short abstract is Nov. 2, 2012; notification regarding author guidelines for the preparation of the full paper will be sent by Dec. 31, 2012; the deadline for receipt of the full paper is Feb. 27, 2013. For registration form and further information, e-mail Osama Al-Erhayem at [email protected].

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WELDING JOURNAL 107

ADVERTISER INDEX Abicor Binzel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 www.binzel-abicor . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 542-4867

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Hobart Inst. of Welding Tech. . . . . . . . . . . . . . . . . . . . . . . . . . . .62 www.welding.org . . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 332-9448

Atlas Welding Accessories, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . .89 www.atlaswelding.com . . . . . . . . . . . . . . . . . . . . . .(800) 962-9353

Hodgson Custom Rolling, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . .5 www.hcrsteel.com . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 263-2547

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Lincoln Electric Co. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .OBC www.lincolnelectric.com . . . . . . . . . . . . . . . . . . . . .(216) 481-8100

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BLUCO Modular Fixturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 www.Bluco.com . . . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 535-0135

NASCC The Steel Conference . . . . . . . . . . . . . . . . . . . . . . . . . .101 www.aisc.org/nascc . . . . . . . . . . . . . . . . . . . . . . . . .(312) 670-2400

BUG-O Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 www.bugo.com . . . . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 245-3186

National Bronze & Metals, Inc. . . . . . . . . . . . . . . . . . . . . . . . . .28 www.nbmmetals.com . . . . . . . . . . . . . . . . . . . . . . . .(713) 869-9600

Camfil Farr Air Polution Control . . . . . . . . . . . . . . . . . . . . . . . . .2 www.camfilfarrapc.com . . . . . . . . . . . . . . . . . . . . .(800) 479-6801

OTC Daihen, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 www.daihen-usa.com . . . . . . . . . . . . . . . . . . . . . . . .(888) 682-7626

Carell Corp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 www.carellcorp.com . . . . . . . . . . . . . . . . . . . . . . . . .(251) 937-0948

Pferd, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 www.pferdusa.com . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 342-0915

Champion Welding Alloys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 www.ChampionWelding.com . . . . . . . . . . . . . . . . .(800) 321-9353

Red-D-Arc Weldrentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 www.reddarc.com . . . . . . . . . . . . . . . . . . . . . . . . . . .(866) 733-3272

Commercial Diving Academy . . . . . . . . . . . . . . . . . . . . . . . . . . .29 www.commercialdivingacademy.com . . . . . . . . . . .(888) 974-2232

Revco Industries, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 www.bsxgear.com . . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 527-3826

Cor-Met . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 www.cor-met.com . . . . . . . . . . . . . . . . . . . . . . . . . . .(800) 848-2719

Robovent Products Group, Inc. . . . . . . . . . . . . . . . . . . . . . . . . .19 www.robovent.com . . . . . . . . . . . . . . . . . . . . . . . . .(888) 762-68368

Diamond Ground Products, Inc. . . . . . . . . . . . . . . . . . . . . . . . .53 www.diamondground.com . . . . . . . . . . . . . . . . . . .(805) 498-3837

Select Arc, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .IFC www.select-arc.com . . . . . . . . . . . . . . . . . . . . . . . . .(937) 295-5215

Diamond X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 www.diamondxtools.com . . . . . . . . . . . . . . . . . . . . .(800) 447-4248

Sumner Manufacturing Co., Inc. . . . . . . . . . . . . . . . . . . . . . . . .28 www.sumner.com . . . . . . . . . . . . . . . . . . . . . . . . . . .(888) 999-6910

Divers Academy International . . . . . . . . . . . . . . . . . . . . . . . . . .21 www.diversacademy.com . . . . . . . . . . . . . . . . . . . . .(800) 238-3483

Thermal Arc/Thermadyne Industries . . . . . . . . . . . . . . . . . . . . .1 www.thermalarc.com . . . . . . . . . . . . . . . . . . . . . . . .(866) 279-2628

Electron Beam Technologies, Inc. . . . . . . . . . . . . . . . . . . . . . . . .63 www.electronbeam.com . . . . . . . . . . . . . . . . . . . . . .(815) 935-2211

Triangle Engineering, Inc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62 www.trieng.com . . . . . . . . . . . . . . . . . . . . . . . . . . . .(781) 878-1500

FABTECH 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65 www.fabtechexpo.org . . . . . . . . . . . . . . . .(800) 443-9353, ext. 297

Weld Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61 www.WeldEngineering.com . . . . . . . . . . . . . . . . . .(508) 842-2224

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Weld Hugger, LLC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88 www.weldhugger.com . . . . . . . . . . . . . . . . . . . . . . . .(877) 935-3447

Fischer Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 www.fischerengr.com . . . . . . . . . . . . . . . . . . . . . . . .(937) 754-1750

WELDMEX 2012 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87 www.awsweldmex.com . . . . . . . . . . . . . . .(800) 443-9353, ext. 297

Fronius Perfect Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 www.fronius-usa.com . . . . . . . . . . . . . . . . . . . . . . .(810) 220-4414

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Gedik Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 www.gedikwelding.com . . . . . . . . . . . . . . . . . . .+90 216 378 50 00 Greiner Industries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 www.greinerindustries.com . . . . . . . . . . . . . . . . . .(800) 782-2110 Gullco International, Inc. - U.S.A. . . . . . . . . . . . . . . . . . . . . . . .63 www.gullco.com . . . . . . . . . . . . . . . . . . . . . . . . . . . .(440) 439-8333 108 MARCH 2012

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SUPPLEMENT TO THE WELDING JOURNAL, MARCH 2012 Sponsored by the American Welding Society and the Welding Research Council

Continuous Cooling Transformation Behavior in the CGHAZ of Naval Steels Continuous cooling transformation diagrams have been constructed for the coarse-grain heat-affected zone of HSLA-65, HSLA-100, and HY-100 steels

ABSTRACT Continuous cooling transformation (CCT) diagrams were developed for the simulated coarse-grain heat-affected zone (CGHAZ) of HSLA-65, HSLA-100, and HY100 naval steels. Samples were heated to a peak temperature of 1300°C in the Gleeble™ and then cooled over a range of cooling rates representative of actual practice. The Ms, Mf, AC3, and AC1 temperatures were determined using dilatometric analysis for construction of the CCT diagrams. Grain coarsening was observed in the simulated CGHAZ for all three steels and was most pronounced in HY-100. Dissolution of precipitates (carbides) in the austenite at the high simulation temperature was responsible for excessive austenite grain coarsening, with HSLA-65 exhibiting the smallest prior austenite grain size. Depending on the cooling rate, martensite, bainite, ferrite, and pearlite can form in the CGHAZ microstructure for HSLA-65. For HSLA-100 and HY-100, only martensite and bainite were observed over the range of cooling rates that were simulated. It can be concluded that HY-100 has the highest hardenability while HSLA-65 has the lowest from the constructed CCT diagrams. Using these diagrams, it is possible to identify cooling rates that can avoid the formation of high hardness martensite in CGHAZ in order to ensure resistance to hydrogen-induced cracking. This is particularly a concern for HY-100 because of its higher carbon content and hardenability relative to HSLA-65 and HSLA-100, and thereby has the potential for forming much higher hardness martensite in the CGHAZ.

Introduction Because of their good combination of high strength and low-temperature toughness, high-strength low-alloy steels (HSLA) are widely used in naval shipbuilding and will continue to be the principal structural materials in the future. HSLA steels have very low-carbon content (usually less than 0.1 wt-%) and less than 5 wt-% total alloying additions, including Mo, Nb, Ti, V, Mn, Cu, Cr, Ni, and others. Based on low-carbon content and a finegrained microstructure, HSLA steels have better, or at least comparable, weldability (resistance to hydrogen-induced cracking) compared to mild steels but have a much higher strength and toughness (Refs. 1, 2). The thermomechanical-controlled processing (TMCP) technique is utilized to X. YUE ([email protected]),, J. C. LIPPOLD, B. T. ALEXANDROV, and S. S. BABU are with the Welding Engineering Program, The Ohio State University, Columbus, Ohio.

strengthen these steels through the development of very fine grain size in the range of 5 to 10 μm (Refs. 3, 4). In addition, these steels contain various carbides, nitrides, and/or carbonitrides that are finely dispersed in the microstructure. These precipitates act to impede the dislocation motion and thereby provide a secondary hardening effect (Refs. 5, 6). From a weldability standpoint, one advantage of HSLA steels over older generation naval steels is that preheat can be either entirely avoided, or only low-temperature preheat is required. However, welding does

KEYWORDS Continuous Cooling Transformation Microstructure CGHAZ HSLA-65 HSLA-100 HY-100

alter the carefully designed microstructure of HSLA steels as a result of heat-affected zone (HAZ) thermal cycles that exceed the transformation temperature (Refs. 7–9). The microconstituents commonly observed in the weld metal and HAZ of HSLA steels were summarized by Liu (Ref. 10). It has been reported that precipitates could either coarsen or dissolve in the steel matrix during the heating cycle, which can lead to excessive austenite grain growth in the HAZ due to the absence of the pinning effect of precipitates on austenite grain boundaries (Refs. 11, 12). The coarse grain size decreases the nucleation sites for high-temperature transformation products such as ferrite and pearlite, tending to suppress their formation. If the cooling rate is sufficiently high, martensite will form in the HAZ, which can potentially make the HAZ susceptible to hydrogen-induced cracking (Refs. 13–15). This is particularly a problem in the coarse grain heat-affected zone (CGHAZ), where grain growth is most pronounced at peak temperatures above 1200°C. An understanding of the continuous cooling transformation behavior of the CGHAZ of HSLA steel weldments and the construction of corresponding CCT diagrams is necessary in order to optimize welding parameters to avoid the formation of deleterious microstructures such as hard martensite (Ref. 16). For the purpose of comparison, a CCT diagram for the CGHAZ of HY-100 has also been constructed. This paper describes the continuous cooling transformation behavior of the CGHAZ of HSLA-65, HSLA-100, and HY-100 steels. The microstructure resulting from austenite decomposition at different cooling rates is characterized, and corresponding CCT diagrams are constructed.

Experimental Procedure The chemical compositions of the HSLA-65, HSLA-100, and HY-100 steels

WELDING JOURNAL 67-s

WELDING RESEARCH

BY X. YUE, J. C. LIPPOLD, B. T. ALEXANDROV, AND S. S. BABU

B

A

20 µm

20 µm

C

WELDING RESEARCH

20 µm

Fig. 1 — Optical micrographs of the three naval steels. A — HSLA-65; B — HSLA-100; C — HY-100. 2% Nital etch.

used in this investigation are provided in Table 1. The base metal microstructures of the three steels are shown in Fig. 1A–C. It can be seen that the HSLA-65 microstructure consists of fine equiaxed ferrite grains with a grain size in the range of 4–6 μm. HSLA-100 exhibits a quenched and tempered martensite and/or bainite mi-

Fig. 2 — Determination of AC3, AC1, Ms , and Mf (at maximum cooling rate) from dilatation curve.

crostructure. The precipitates in HSLA-65 and HSLA-100 consist of carbides and/or carbonitrides containing Nb or V, and additional carbides precipitating during the tempering process and/or the ε-copper phase for HSLA-100 (Refs. 2, 4, 6, 16, 17). Similar to HSLA-100, the HY-100 steel microstructure is also quenched and tem-

Table 1 — Chemical Compositions of Naval Steels Element (wt-%) C Mn Si P S Cu Ni Cr Mo V Nb Ti

68-s

HSLA-65 0.074 1.35 0.24 0.011 0.006 0.25 0.34 0.14 0.06 0.058 0.018 0.012

MARCH 2012, VOL. 88

HSLA-100 0.051 0.90 0.25 0.008 0.002 1.17 1.58 0.60 0.37 <0.01 0.017 <0.01

HY-100 0.18 0.28 0.21 0.008 0.002 0.15 2.32 1.37 0.26 <0.01 <0.01 <0.01

pered martensite with carbides that form during tempering. Samples for CGHAZ simulation using the Gleeble 3800™ were machined from the three steel plates. The samples were 6.5 mm in diameter by 100 mm long. A Type K control thermocouple was welded at the midsection of the test sample. A dilatometer was used for measuring the diametric dilation change of these samples. All testing was done in a partial vacuum of approximately 10–3 torr. The samples were heated to a peak temperature of 1300°C (simulating the CGHAZ temperature) at a linear rate of 200°C/s and held at peak temperature for one second. A peak temperature of 1300°C was selected because it is representative of the CGHAZ in all three steels and avoids the possibility of sample melting at higher peak temperatures. For the cooling portion, twelve cooling rates were employed for each steel to simulate a wide range of welding conditions representative of actual practice. The different cooling rates were obtained by selecting copper or stainless steel jaw sets, and adjusting the free span (spacing between jaws). The cooling rate is defined by

A

B

C

Fig. 3 — Vickers hardness profile as a function of t8/5 for three naval steels. A — HSLA-65; B — HSLA-100; C — HY-100.

B

C

20 µm

20 µm

20 µm

E

D

F

20 µm

20 µm

20 µm

Fig. 4 — Optical micrographs of CGHAZ of HSLA-65 at different cooling rates. A — t8/5 = 5.2 s; B — t8/5 = 8.3 s; C — t8/5 = 21.1 s; D — t8/5 = 41.8 s; E —t8/5 = 57.2 s; F — t8/5 = 84.2 s; 2% Nital etch.

the value t8/5, which is the cooling time from 800° to 500°C. In this investigation, the t8/5 was in the range of a few seconds to around 100 s, as shown in Table 2. The CCT diagrams are thereby constructed using the dilatometry data obtained at different t8/5 values. The method has been specified in the paper by Eldis (Ref. 18). Metallographic analysis was conducted on samples taken at the midsection (hot zone) of the dilatometry specimens close to the location where the thermocouple was attached. Samples were polished and etched with 2% nital and examined using both optical and scanning electron microscopy. For TEM analysis, thin slices were cut using a low-speed diamond saw, and then they were mechanically ground to a thickness of about 80 μm. The 3-mmdiameter discs were punched and electrolytically thinned using a twin jet polisher in a solution of 33% nitric acid and 67% methanol at –10°C. The TEM foils were evaluated in a Philips CM200 TEM operated at 200 kV.

The prior austenite grain size was measured in accordance with ASTM E 112-96. Vickers hardness measurements were conducted on the as-polished samples using a 1-kg load, in accordance with ASTM E 384-10.

Results and Discussion Prior austenite grain size plays an important role in the continuous cooling transformation behavior of HSLA and HY steels. Excessive austenite grain coarsen-

Table 2 — t8/5 and Corresponding Average Cooling Rates for Three Naval Steels HSLA-65

HSLA-100

HY-100

t8/5 (s)

Avg Cooling Rate (°C/s)

t8/5 (s)

Avg Cooling Rate (°C/s)

t8/5 (s)

Avg Cooling Rate (°C/s)

3.0 3.5 5.2 8.3 10.5 21.1 27.2 36.4 41.8 57.2 75.6 84.2

100 85.7 57.7 36.1 28.6 14.2 11.0 8.2 7.2 5.2 4.0 3.6

2.4 3.6 8.2 13.4 15.5 17.7 37.8 41.4 51.4 60.9 86.8 106.3

125 83.3 36.6 22.4 19.4 16.9 7.9 7.2 5.8 4.9 3.5 2.8

3.6 4.3 5.7 10.6 14.1 19.1 21.2 43.5 66.4 74.1 106.6 113.4

83.3 69.8 52.6 28.3 21.3 15.7 14.2 6.9 4.5 4.0 2.8 2.6

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A

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A

B

C

D

E

F

Fig. 5 — SEM and TEM micrographs for simulated CGHAZ of HSLA-65. A — t8/5 = 3 s; B — t8/5 = 21.1 s; C— t8/5 = 84.2 s; D — HSLA-65 base metal microstructure; E — t8/5 = 84.2 s (bright-field TEM); F — HSLA-65 base metal microstructure (bright-field TEM).

ing in the CGHAZ during welding is generally detrimental to HAZ mechanical properties. For the purpose of comparison of the austenite grain coarsening tendency of the three steels, the prior austenite grain size was measured at the maximum cooling rate for each test steel, in which circumstance the austenite coarsening during cooling before the start of transformation was most restricted and an accurate comparison among steels was 70-s

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ensured. The ASTM grain size number (and average grain diameter) for the simulated CGHAZ of HSLA-65, HSLA-100, and HY-100 were determined to be 7.5 (27 μm), 5.8 (50 μm), and 4.5 (75 μm), respectively. All the steels exhibited an essentially equiaxed grain structure. The AC1 and AC3 temperatures on heating were determined by identifying the deviation points from the dilation curve, as shown in Fig. 2. Since the heating

process was identical for all twelve simulated thermal cycles, the average value of AC1 and AC3 and the standard deviation are calculated and provided in Table 3. The Vickers hardness values as a function of t8/5 for the three steels are shown in Fig. 3A–C. Generally speaking, for all three steels, at the minimum t8/5 (or highest cooling rate), the Vickers hardness of simulated CGHAZ reaches the maximum value based on the carbon content of the steel. At a t8/5

of 3.6 s, HY-100 exhibits the highest hardness at approximately 450 HV, while HSLA65 and HSLA-100 are in the range from 350 to 360 HV. With increasing t8/5 (slower cooling rate), the Vickers hardness value decreases as a result of different types of austenite decomposition products at different cooling rates. The formation of predominantly martensite at high cooling rates leads to higher hardness, relative to bainite and ferrite which form at lower cooling rates. The Vickers hardness results can then be used in combination with metallographic analysis to determine the austenite decomposition products.

B

A

20 µm

20 µm

D

C

Microstructure Characterization of HSLA-65

20 µm

E

20 µm

F

20 µm

20 µm

Fig. 6 — Optical micrographs of CGHAZ of HSLA-100 at different cooling rates. A — t8/5 = 2.4 s; B — t8/5 = 8.2 s; C — t8/5 = 37.8 s; D — t8/5 = 60.9 s; E — t8/5 = 86.8 s; F — t8/5 = 106.3 s. 2% Nital etch.

temperature, but based on the absence of any apparent austenite in the microstructure, it is surmised that martensite is the predominant transformation product. By increasing t8/5 to 5.2 s, ferrite and needle-like bainite appear in the transformation microstructure as shown in Fig. 4A. It is generally agreed that bainitic microstructures can be divided into upper and lower bainite, the main difference between them is that for the lower bainite,

the carbides precipitate preferentially within bainite laths, while for upper bainite, carbides precipitate along the bainite lath boundaries (Ref. 19). However, it should be noted that upper and lower bainite are not differentiated in the present study; both of them are generally categorized as bainite, which exhibits a needlelike lath morphology, as shown at higher magnification in the SEM in Fig. 5B. It is shown in Fig. 4B and C that at t8/5

Table 3 — Important Parameters Determined for Naval Steels

HSLA-65 HSLA-100 HY-100

Prior Austenite Grain Size (μm)a

AC1 (°C)

AC3 (°C)

Msb (°C)

Mf b (°C)

CGHAZb Max Hardness (HV) b

Base Metal Hardness (HV)

27±3.8 50±3.6 75±5.8

770±6.4 765±4.8 765±6.0

865±5.2 850±6.7 820±4.3

486 466 406

282 278 221

360 353 454

201 284 283

CEc

0.43 0.62 0.75

(a) PAGS for peak temperature of 1300°C with hold time of 1 s. (b) Ms, Mf, CGHAZ Max hardness determined at minimum t8/5 (3.0, 2.4, 3.6 s for HSLA-65, HSLA-100, and HY-100, respectively). (c) CEIIW = C +(Mn+Si)/6+(Cr+Mo+V)/5+(Ni+Cu)/15.

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Optical micrographs of the simulated CGHAZ of HSLA-65 at different cooling rates are shown in Fig. 4A–F. In combination with SEM and TEM micrographs (as shown in Fig. 5A–F) and Vickers hardness results (Fig. 3A), austenite decomposition products at different cooling rates can be determined. Note that not all the optical, SEM or TEM microstructures at all the cooling rates are presented here, only some typical ones are used to illustrate variation in the transformation products as a function of cooling rate. At the minimum t8/5 of 3 s, martensite forms in the CGHAZ, as shown in the SEM micrograph in Fig. 5A. This is a typical lath martensite microstructure, in which prior austenite grain boundaries and lath martensite packet boundaries are discernable. The possibility of formation of other phases, other than low-carbon lath martensite, can be excluded since the transformation microstructure exhibits a hardness of 360 HV, while at the same time the carbon content is only 0.074 wt-%. The combined effect of fast cooling rate and coarsening of prior austenite grains promotes the formation of martensite instead of ferrite and pearlite, which form based on a diffusion-controlled transformation mechanism. The martensite start (Ms) and finish temperature (Mf) were determined to be 486° and 282°C, respectively. It should be noted that the transformation is not necessarily complete at the Mf

B

A

Fig. 7 — SEM micrographs for simulated CGHAZ of HSLA-100. A — t8/5 = 2.4 s; B — t8/5 = 60.9 s.

WELDING RESEARCH

of 8.3 and 21.1 s, a small amount of ferrite forms along the prior austenite grain boundaries. Long needle-like bainite grows throughout the prior austenite grain resulting in an aspect ratio greater than 10:1. The dark-etching phase observed between bainite should be martensite. When t8/5 is 41.8 s, as shown in Fig. 4D, the microstructure is still a mixture of ferrite, bainite, and martensite. However, the fraction of ferrite increases while martensite decreases in comparison with Fig. 4B, C. This is the reason why the hardness continues to decrease as t8/5 increases. When t8/5 is 57.2 and 84.2 s, as shown in Fig. 4E, F, small dark pearlite islands form adjacent to the equiaxed ferrite grains. Because the equiaxed ferrite constitutes the majority of the transformation microstructure, the Vickers hardness values are 230 and 228 HV for these cooling times, which are only slightly higher than the base material hardness of 201 HV. The ferritic microstructure with much lower hardness and smaller grain size is less susceptible to hydrogen-induced cracking compared with the martensitic microstructure forming at fast cooling rates (Ref. 20). The transformation microstructure at the minimum cooling rate is further investigated as shown in Fig. 5C. The ferrite grain boundaries can be clearly observed, and no obvious precipitates appear along the grain boundaries or within the ferrite grains. However, in the base metal microstructure shown in the SEM micrograph in Fig. 5D, various precipitates can be clearly identified along the ferrite grain boundaries as well as much smaller precipitates within the grains. Two bright-field TEM images at higher magnification are also provided as shown in Fig. 5E, F. It can be seen in Fig. 5F that clusters of precipitates exist in the HSLA-65 base metal before thermal cycle simulation, but they disappear after the thermal cycle as shown in Fig. 5E. It is therefore concluded that 72-s

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the precipitates in HSLA-65 dissolve during the high-temperature exposure (Tpeak = 1300°C) of the CGHAZ thermal cycle, and even at the minimum cooling rate, significant reprecipitation during cooling still does not occur. This explains why the prior austenite grain size increases fivefold relative to the base metal grain size. As the precipitates dissolve on heating to high temperature, no grain boundary pinning is possible and austenite grain coarsening occurs. Although the carefully designed HSLA-65 base metal microstructure of fine grain size and dispersed precipitates is absent in the CGHAZ, a transformation microstructure developed at minimum cooling rates can produce lower hardness levels approaching that of the base metal. Microstructure Characterization of HSLA-100

Optical micrographs of the simulated CGHAZ of HSLA-100 at different cooling rates are shown in Fig. 6A–F. At the minimum t8/5 of 2.4 s, a peak Vickers hardness value of 353 HV is achieved. In combination with the microstructure shown in Fig. 6A, it can be concluded that the highcooling rate transformation product is martensite. Because HSLA-100 has a lowcarbon content (0.051 wt-%), the martensite formed should be low-carbon lath martensite, whose morphology can be observed in Fig. 7A. By increasing t8/5 to 8.2 s, light-colored bainite appears in the microstructure, which nucleates from the prior austenite grain boundaries and grows into the grain interior. Some of the needle-like bainite has a large aspect ratio and can grow across the entire prior austenite grain as was seen in HSLA-65. The dark-etching phase between the bainite laths is martensite. By increasing t8/5 up to 106.3 s, as shown in Fig. 6C–F, no obvious ferrite or pearlite can be observed (as also shown in

Fig. 7B), and the microstructure is still a mixture of bainite and martensite. With decreasing cooling rate, the fraction of bainite increases and martensite decreases. The microstructure change results in a gradual decrease in the Vickers hardness as the cooling rate decreases as shown in Fig. 3B; that is, if the fraction of bainite in the microstructure increases, then the hardness decreases. At the minimum cooling rate, bainite dominates the microstructure as shown in Fig. 6F, and the minimum hardness value of 270 HV is obtained, which is less than the hardness (284 HV) of the tempered martensite base metal microstructure. Microstructure Characterization of HY-100

The optical micrographs of the simulated CGHAZ of HY-100 at different cooling rates are shown in Fig. 8. As shown in Fig. 8 A–C, the microstructure clearly exhibits a martensitic morphology. While in Fig. 8D, light-colored bainite appears, and with increasing t8/5, the fraction of bainite increases and martensite decreases as shown in Fig. 8E, F. This can be confirmed by the Vickers hardness data in Fig. 3C. The maximum hardness value of 454 HV is achieved at the minimum t8/5 of 3.6 s. In the t8/5 range from 3.6 to 21.2 s, a hardness plateau appears indicating that transformation to martensite is complete at these cooling rates. At higher cooling times, the hardness abruptly drops as bainite begins to replace martensite in the microstructure, as shown in Fig. 8D for t8/5 of 43.5 s. Comparison of the Three Steels

For all three steels, complete transformation to martensite occurs in the simulated CGHAZ at the minimum t8/5 of ~3 s. The Ms and Mf temperatures have been determined at this cooling time as previously shown in Table 3. Based on the experimen-

B

C

D

E

F

WELDING RESEARCH

A

Fig. 8 — Optical micrographs of CGHAZ of HY-100 at different cooling rates. A — t8/5= 3.6 s; B — t8/5 = 10.6 s; C — t8/5 = 21.2 s; D t8/5 = 43.5 s; E — t8/5 = 74.1 s; F — t8/5 = 113.4 s. 2% Nital etch.

tal results, CCT diagrams for the CGHAZ of HSLA-65, HSLA-100, and HY-100 have been constructed as shown in Fig. 9. It is generally agreed that the composition and processing route determine the microstructure and properties of steel. For HSLA-65 and HSLA-100, the very fine base metal microstructure is achieved by the utilization of the thermomechanicalcontrolled processing (TMCP) technique. The basic principle of TMCP is to refine

and/or deform the austenite grains in a carefully controlled rolling process, whereby austenite recrystallization and grain growth are inhibited by stable precipitates such as Nb-rich carbides and/or carbonitrides that remain undissolved at the rolling temperature. The refined austenite then transforms to the desired microstructure with very fine grain size. This well-developed base metal microstructure is completely destroyed in the

CGHAZ by transformation to austenite and complete dissolution of the carbides (Fig. 5 C–F). Therefore, the pinning effect of precipitates on austenite grain boundaries is absent (Refs. 21, 22) and results in prior austenite grain size of 27 and 50 μm for HSLA-65 and HSLA-100, respectively. For HY-100, which is a quenched and tempered steel with no grain boundary pinning precipitates involved, even coarser prior austenite grains (75 μm) are ob-

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B

A

C

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Fig. 9 — CCT diagrams for the CGHAZ of HSLA-65, HSLA-100, and HY100. A — HSLA-65; B — HSLA-100; C — HY-100.

served in the simulated CGHAZ microstructure. The coarse prior austenite grains provide fewer nucleation sites for ferrite on the grain boundaries compared with fine grains and, therefore, tend to more readily promote the formation of martensite. In comparison to HSLA-65 and HSLA100, the CGHAZ of HY-100 has much coarser prior austenite grain size and higher hardness (~450 HV). The difference in martensite hardness among these steels (Table 3) is directly attributable to the difference in carbon content. As for the Ms temperature, HY-100 exhibits the lowest and HSLA-65 the highest, as a direct influence of the level of alloying additions and the related carbon equivalent values (Table 3). From the CCT diagrams for the simulated CGHAZ microstructure, transformation products including ferrite, pearlite, bainite, and martensite can form in HSLA-65 while only bainite and martensite form in HSLA-100 and HY-100. The difference in carbon equivalent is also reflected in the three CCT diagrams. The

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Fig. 10 — Zone classification of steels for HIC cracking susceptibility according to AWS D1.1/D1.1M:2010 (Ref. 23).

approximate critical t8/5 to form martensite is 3.5 s, 3.6 s, and 21.2 s for HSLA-65, HSLA-100, and HY-100, respectively. Although the carbon content of the three steels is relatively low and lath martensite is the predominant CGHAZ microstructural constituent at these cooling rates, it is generally advisable to avoid the formation of full martensite microstructures with high hardness in CGHAZ in order to insure HIC resistance. The widely accepted AWS D1.1 standard (Ref. 23) is referred here in order to show the different requirements for preheat and interpass temperatures when welding these steels as to insure resistance to hydrogen-induced cracking (HIC). As shown in Fig. 10, HSLA-65 and HSLA-100 are classified in Zone I due to their low carbon content and carbon equivalent, which means that HIC is unlikely when welding the two steels, but may occur with high hydrogen levels or high restraint. HY-100 is classified in Zone III, which means that the hydrogen control method should be used to determine preheat. In this analysis, one assumes the situation of

welding the three naval steels in real practice with a hydrogen level of H2 (medium hydrogen, 5–10 mL/100 g) and medium restraint as encountered in fillet or groove joints, and the thickness of all the three steel plates to be welded is the same at 12.7 mm (0.5 in.). This combination of H2 hydrogen content and medium restraint level is representative of many commonly encountered situations. Based on the AWS D1.1 standard, the preheat and interpass temperature of 145°C should be used when welding HY-100 as to insure HIC resistance. While for HSLA-65 and HSLA-100, preheat can be avoided at the same situation (if welding at ambient temperature of 20°C). Note that when welding these steels in actual shipyard conditions, all the factors, such as welding consumables and welding process used, must be taken into account when determining the preheat and interpass temperatures. In practice, the Navy recommends no preheat or interpass temperature control for HSLA-65, although some preheat may be used in some situations to remove moisture. For HSLA-100,

Conclusions 1. The prior austenite grain size of the simulated CGHAZ (1300°C peak temperature) of HSLA-65, HSLA-100, and HY100 was determined to be 27, 50, and 75 μm, respectively. 2. The Ms temperatures of HSLA-65, HSLA-100, and HY-100 were determined to be 486°, 466°, and 406°C, respectively. 3. The austenite decomposition products are strongly dependent on the cooling time (t8/5). For HSLA-65, at high cooling rates (t8/5<3.5 s), martensite forms in the CGHAZ microstructure. At intermediate cooling rates (5.2 s 8.2 s for HSLA-100 and t8/5 >43.5 s for HY-100.

5. The peak martensite hardness value obtained in the simulated CGHAZ of HY100 (454 HV) is much higher than that of HSLA-65 (360 HV) and HSLA-100 (353 HV), which is primarily a function of the higher carbon content in HY-100 (0.18 wt%) relative to HSLA-65 (0.074 wt-%) and HSLA-100 (0.051 wt-%). 6. Based on the CCT diagrams developed for these steels, the hardenability of HY-100 is the highest while HSLA-65 is the lowest. 7. More stringent welding conditions (higher preheat temperature) should be applied when welding HY-100 in comparison with welding HSLA-100 and HSLA65. This is because of higher carbon content and alloy addition in HY-100, possible formation of higher hardness martensite, and larger prior austenite grain size in the CGHAZ of HY-100. 8. In actual practice, where high-hydrogen and high-restraint levels are encountered and resistance to HIC is the primary concern, beside the application of preheat, the actual t8/5 is recommended to be greater than the critical value to avoid martensite formation. For HSLA-65, it is advisable to obtain an equiaxed ferrite microstructure forming at slow cooling rates. While for HSLA-100 and HY-100, it is advisable to control the cooling rate to decrease the fraction of martensite in the microstructure and thus decrease the CGHAZ hardness. Acknowledgment The authors gratefully acknowledge the financial support of the Office of Naval Research, Award No. N000140811000. The grant officers are Dr. Julie Christodoulou and Dr. William Mullins. The authors also would like to thank Johnnie DeLoach, Matthew Sinfield, and Jeffrey Farren with the Naval Surface Warfare Center Carderock Division, West Bethesda, Md., for providing the steels used in this study and for valuable discussions regarding the weldability of these steels. References 1. Nemat-Nasser, S., and Guo, W. G. 2005. Thermomechanical response of HSLA-65 steel plates: experiments and modeling. Mechanics of Materials 37: 379–405. 2. Czyryca, E. J. 1993. Advances in high strength steel technology for naval hull construction. Key Engineering Materials 84–85: 491–520. 3. Bhadeshia, H. K. D. H. 2006. Steels: Microstructure and Properties. pp. 209–220, UK, Elsevier Ltd. 4. Sampath, K. 2006. An understanding of HSLA-65 plate steels. Journal of Materials Engineering and Performance 15(1): 32–40. 5. Timokhina, I. B., Hodgson, P. D., Ringer, S. P., Zheng, R. K., and Pereloma, E. V. 2007.

Precipitate characterization of an advanced high-strength low-alloy (HSLA) steel using atom probe tomography. Scripta Materialia 56: 601–604. 6. Mishra, S. K., Das, S., and Ranganathan, S. 2002. Precipitation in high strength low alloy (HSLA) steel: A TEM study. Materials Science and Engineering A 323: 285–292. 7. Thompson, S. W., Colvin, D. J., and Krauss, G. 1996. Austenite decomposition during continuous cooling of an HSLA-80 plate steel. Metallurgical and Materials Transactions A 27A: 1557–1571. 8. Fonda, R. W., and Spanos, G. 2000. Microstructural evolution in ultra low-carbon steel weldments — Part 1: Controlled thermal cycling and continuous cooling transformation diagram of the weld metal. Metallurgical and Materials Transactions A 31A: 2145–2153. 9. Yang, Z., and DebRoy, T. 1999. Modeling macro-and microstructures of gas-metal arc welded HSLA-100 steel. Metallurgical and Materials Transactions B 30B: 483–493. 10. Liu, S. 1992. Metallography of HSLA steel weldments. Key Engineering Materials 69–70: 1–20. 11. Ashby, M. F., and Easterling, K. E. 1982. A first report on diagrams for grain growth in welds. Acta Metall 30: 1969–1978. 12. Shome, M., Gupta, O. P., and Mohanty, O. N. 2004. A modified analytical approach for modeling grain growth in the coarse grain HAZ of HSLA steels. Scripta Materialia 50: 1007–1010. 13. Savage, W. F., Nippes, E. F., and Szekeres, E. S. 1976. Hydrogen induced cold cracking in a low alloy steel. Welding Journal 55: 276-s to 283-s. 14. Vasudevan, R., Stout, R. D., and Pense, A. W. 1981. Hydrogen-assisted cracking in HSLA pipeline steels. Welding Journal 60(9): 155-s to 168-s. 15. Savage, W. F., Nippes, E. F., and Sawhill, J. M., Jr. 1976. Hydrogen induced cracking during implant testing of alloy steels. Welding Journal 55: 400-s to 407-s. 16. Shome, M., and Mohanty, O. N. 2006. Continuous cooling transformation diagrams applicable to the heat-affected zone of HSLA80 and HSLA-100 steels. Metallurgical and Materials Transactions A 37A: 2159–2169. 17. Caron, J. 2010. Weldability evaluation of naval steels. PhD dissertation. Columbus, Ohio, The Ohio State University. 18. Eldis, G. T. 1977. A critical review of data sources for isothermal transformation and continuous cooling transformation diagrams. Hardenability Concepts with Application to Steels, D. V. Doane and J. S. Kirkaldy, Editors, AIME/ASM. 19. Bhadeshia, H. K. D. H. 2001. Bainite in Steels: Transformations, Microstructure and Properties. pp. 63–75, London, UK, IOM Communications Ltd. 20. Kou, S. 2003. Welding Metallurgy. pp. 410–417, Hoboken, N.J., John Wiley & Sons, Inc. 21. Easterling, K. 1992. Introduction to the Physical Metallurgy of Welding. p. 145, Oxford, UK, Butterworth-Heinemann Ltd. 22. Shome, M., Sarma, D. S., Gupta, O. P., and Mohanty, O. N. 2003. Precipitate dissolution and grain growth in the heat-affected zone of HSLA-100 steel. ISIJ International 43(9): 1431–1437. 23. AWS D1.1/D1.1M:2010. Structural Welding Code — Steel. American Welding Society, Miami, Fl.

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a preheat of 15°C (60°F) and a maximum interpass of 149°C (300°F) is recommended, while for HY-100 a minimum preheat of 52°C (125°F) and maximum interpass of 149°C (300°F) is commonly used. These recommendations are for plate thicknesses less than 25.4 mm (1-in.). Thicker sections would require higher preheat temperatures because of the higher restrain levels. Note that the preheat requirement for HY-100, based on AWS D1.1, is conservative — requiring a much higher minimum preheat than what is actually used in practice. Based on the results presented here, in actual practice where resistance to HIC is the primary concern, welding parameters can be selected such that the effective t8/5 for each steel is greater than its critical value in order to avoid full martensite formation. However, it should be noted that formation of ferrite and/or bainite in CGHAZ may lead to a strength decrease. Therefore, there is a “trade-off” between HIC resistance and weld HAZ strength. This is particularly important for HY-100, which has the highest hardenability and achieves the highest hardness in CGHAZ. More stringent welding conditions (higher preheat temperatures) should be applied when welding HY-100 in comparison with welding HSLA-100 and HSLA-65, because of the higher carbon and alloy content in HY-100, and the likely formation of martensite with higher hardness (~ 450 HV) over a wide range of cooling rates, as well as larger prior austenite grain size in the CGHAZ of HY-100. Based on the more stringent needs regarding preheat, the advantage of the HSLA series steels over the HY series has been clearly demonstrated.

Developing an Alternative Heat Indexing Equation for FSW An alternative heat indexing equation is proposed that considers the heat generation terms and thermal dissipation BY J. A. QUERIN AND J. A. SCHNEIDER

ABSTRACT

WELDING RESEARCH

In friction stir welding (FSW), a nonconsumable, rotating weld tool is used to impart large shear deformations under a simultaneous compressive stress state to produce a solid-state weld joint between the former faying surfaces. The process results in a refinement of the microstructure in the stir zone (SZ) in response to the heat and plastic deformation. The peak temperature in the weldment is balanced between generation via frictional and deformational heating, and thermal dissipation. Heat index equations published in the literature do not consider the effect of thermal dissipation. The thermal dissipation is dependent on the travel velocity, weld tool geometry, and thermal properties of the workpiece and process tooling that includes the tool, spindle, and backing anvil. Maintaining a constant temperature is important in ensuring the production of high-quality welds over a range of weld schedules. This study proposes an alternative heat indexing (AHI) equation that considers not only the heat generation terms but also the thermal dissipation to ensure a constant peak temperature when modifying or extrapolating weld schedules.

Introduction Friction stir welding (FSW) consists of the following three process parameters: plunge depth/force, travel velocity, and spindle speed. Dependencies between the process parameters and response variables, including plunge force, plow force, weld torque, and temperature, have been reported (Refs. 1–9). Although temperature cannot be directly controlled, the resulting forces and torque are strongly affected by the short- and long-range weld zone temperatures. For a constant spindle speed, the torque would be expected to increase as the travel velocity is increased because the long-range weld zone temperature is decreased. Several studies have shown a correlation between the increased travel velocity and increased plow force (Refs. 1, 3, 8), suggesting the tool is encountering material with higher flow stresses due to shorter times at elevated temperatures. Increases in peak temperature measureJ. A. QUERIN ([email protected]) is a welding, materials, and processes engineer, Boeing Defense, Space & Security, Huntsville, Ala. J. A. SCHNEIDER is a professor, Department of Mechanical Engineering, Mississippi State University, Mississippi State, Miss.

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ments have also been correlated with increased travel velocity (Ref. 9), presumably for the same reason. While increased spindle speeds have the largest reported effect on the FSW tool temperature (Refs. 1, 6), it has no reported effect on the plow force (Ref. 3). Although various studies (Refs. 1–9) have targeted the relationships between process parameters and weld tool geometry with response variables, little success has been achieved toward predicting or extrapolating process parameters, especially on the basis of temperature. A heat index relationship, the pseudo heat index (PHI) reported in the literature (Ref. 10), attempts to correlate the heat input during FSW with weld process parameters. However, as Equation 1 (Ref. 10) shows,

KEYWORDS Friction Stir Welding (FSW) Stir Zone (SZ) Heat Indexing Equation Thermal Dissipation Alternative Heat Indexing Heat Generation

it only considers the process parameters of (ω) for spindle speed and (V) for travel velocity. Without including the power generated during the weld, the weld tool geometry, and the thermal properties of the FSW tooling, the PHI relationship cannot accurately predict or be used to extrapolate FSW process parameters based on temperature. PHI =

ω2 V 10000

(1)

Improving the accuracy of FSW model predictions and process scalability requires incorporating the influence from both the process parameters and tooling. As such, this study considers the development of a one-dimensional heat transfer model that includes the geometry of the weld tool, the thermal properties of the workpiece and tooling, and the process parameters. This model is then used as the basis for development of an alternative heat indexing equation for FSW.

Experimental Procedure In the present study, two FSW tools, whose dimensions are summarized in Table 1, were used to produce friction stir welded panels. A cylindrical pin was used on both tools, one with a smooth surface and the other with a threaded surface. Both FSW tools used a smooth, 7-deg concave shoulder and all of the friction stir welds were made using a 2.5-deg tilt angle. Bead-on-plate (BOP) friction stir welds were made along the rolling direction and center width of 150 mm wide × 610 mm long × 6.4 mm thick AA2219-T87 plates. The horizontal weld tool (HWT) at the National Aeronautics and Space Administration’s Marshall Space Flight Center (NASA-MSFC) was used to produce the friction stir welds. During the weld, continuous recordings were made of the zaxis (plunge) force, x-axis (plow) force, weld torque, spindle speed, travel velocity, and x-axis position. The weld torque was

Fig. 1 — Schematic representation of a transverse view of the heat source and sinks associated with FSW. Note the heat flow paths are represented by the arrows.

One-Dimensional Heat Transfer Model

Table 1 — Dimensions of the Weld Tools

Shoulder Diameter Pin Diameter Pin Length

Threaded Pin (mm)

15.5 8.9 4.3

19.1 7.9 4.3

In this study, the temperature (T) refers to the shear surface temperature, and the temperature (T0) refers to a fixed ambient temperature at a distance from the source. For a cylindrical pin, the heat source is approximated as a cylinder, as shown in Fig. 3. In the development of this model, it is assumed that the heat source represents the shear surface and the shear surface is isothermal. The heat loss terms for the model are derived from Fourier’s Law in one dimension, which is expressed in Equation 2 (Ref. 12). In the expression (Qn) is the rate of heat transfer, (k) is the thermal conductivity of the material, (A) is the area through which heat flows, and dT/dn is the temperature gradient with respect to distance in the direction normal to A.

Q = − kA n

Figure 1 shows a schematic of the heat source and sinks considered in the development of an alternative heat indexing equation. The model consists of a power generation term that incorporates the geometry of the FSW tool and process parameters, heat loss terms for conduction within the weldment and through the backing anvil and spindle, and convection required to continuously heat newly incorporated material within the stir zone (SZ). The convective heat loss is dependent on the cross-sectional area of the surface defining the SZ and travel velocity. The surface that denotes the separation of the SZ from the base material (BM) is referred to as the shear surface as illustrated in Fig. 2.

Smooth Pin (mm)

dT dn

(2)

Power Generation

The rate at which work is performed is termed power. In FSW, power is required to rotate the weld tool in the workpiece and traverse along the weld joint. Power for a rotating object is calculated by multiplying the torque and the angular velocity, while the power for traversing longitudinally along the weld joint is calculated by multiplying the force acting in that direction by the velocity in that direction. Reported total weld power calculations for welds that did not contain defects con-

Fig. 3 — Two-dimensional representation of the idealized heat source for the cylindrical pin weld tools.

cluded that the contributions from the tool rotating were in excess of 98% (Ref. 13). Therefore, in this study, the weld power was approximated off of the weld torque and spindle speed. An assumption of the steady-state operation of the FSW process is made in which the contact conditions between the workpiece and FSW tool are assumed to be sticking. This is based on experimental evidence that the FSW tool/workpiece contact conditions are dominated by the sticking contact condition (Ref. 14). The weld torque (M) can be calculated analytically by Equation 3. Other researchers have used similar expressions to calculate the weld torque and power (Refs. 14–16). In Equation 3, (τ) is the flow stress of the material along the shear surface and (r) is the distance from the tool center to the shear surface. The radius (r) is a function of its placement along the z-axis. If the boundary of the shear surface is not known, i.e. radius as a function of the z-axis, then the FSW tool profile can be used for an approximation. This torque multiplied by the spindle speed gives an analytical expression for calculating the weld power. For a cylindrical pin FSW tool where the shear surface is estimated as that of the WELDING JOURNAL 77-s

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measured with a load cell connected to the spindle with a known arm length, thus recording the actual moment that occurs about the spindle as a result of the reaction between the FSW tool and workpiece. To evaluate the accuracy of the PHI relationship and consider the interaction of process parameters and tooling, initial process parameters were based on published values for FSW 6.4-mm-thick plates of AA2219-T87 (Refs. 8, 11). Table 2 summarizes the test matrix used in this study, which was designed using a constant PHI to consider the range of validity (Ref. 10). From reported studies (Refs. 8, 11), a PHI of 0.09 has been correlated with defectfree friction stir welds in AA2219-T87 over a range of travel velocities from 76 to 203 mm/min. For PHIs greater than 0.12, the friction stir welds were reported to show void-type defects. In this study, the travel velocity was calculated for a given spindle speed using a PHI of 0.09. The spindle speed and z-axis force were selected based on initial baseline friction stir welds to determine processing parameters to produce defect-free welds. Differences in z-axis force are attributed to differences in the shoulder diameter.

Fig. 2 — Schematic representation of a cylindrical pin FSW tool and the shear surface separating the stir zone (SZ) from the rest of the weld.

B

A

C

D

Fig. 4 — Longitudinal exit hole macrographs. A — Smooth pin FSW tool at 0.023 mm/rev; B — smooth pin FSW tool at 0.34 mm/rev; C — threaded pin FSW tool at 0.23 mm/rev; and D — threaded pin FSW tool at 0.34 mm/rev.

WELDING RESEARCH

Fig. 5 — Weld power vs. welding velocity using different advances per revolution calculated for the smooth pin FSW tool.

FSW tool profile, Equation 3 is multiplied by the spindle speed and solved yielding Equation 4, an expression for the weld power (Qg). In Equation 4, (Rs) is the radius of the tool shoulder, (R) is the radius of the pin, (H) is the length of the pin, (ω) is the spindle speed, and (τ) is the flow stress of the material along the shear surface.

⎛ dr ⎞ ⎟ ⎝ dz ⎠

M = ∫ τ (2π r 2 ) 1 + ⎜

2

dz

(3)

⎡ ⎢ ⎛R 3 ⎢1 ⎜ s Q = ωτ 2π R g ⎢3 ⎜ R ⎢⎣ ⎝

Fig. 6 — Specific weld energy vs. welding velocity using different advances per revolution calculated for the smooth pin FSW tool.

⎤ ⎞3 ⎥ ⎟ +H⎥ ⎟ R⎥ ⎠ ⎥⎦

(4)

Heat Loss Terms

(R0). The expression for this heat loss is given in Equation 5 where (k w) is the thermal conductivity of the workpiece and (T) is the shear surface temperature.

Qw =

As illustrated in Fig. 1, the heat losses assumed include conduction losses to the workpiece, anvil, and spindle, in addition to a convective heat loss to the workpiece. Each is briefly described in this section. For a cylindrical heat source, the conductive losses to the workpiece (Qw) are approximated as a radial flow of heat from the cylindrical heat source at radius (R) to a fixed temperature (T0) at radius

(T −T0 )2π kw H R ln 0 R

(5)

Conduction losses to the anvil (Qa) are approximated as a spherically radial flow of heat from under the bottom of the pin into a thick block of material as given by Equation 6. The radius of the bottom of the pin (Ra) is assumed equal to (R) for the cylindrical source. In Equation 6, (ka) is the thermal conductivity of the anvil.

Table 2 — Test Matrix for FSW AA2219-T87 Spindle Speed (rev/min) 200 300 400 500

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Travel Velocity (mm/min) 46 102 180 282

Forge Force (kN) Smooth Threaded Surface Surface Pin 5/16-24 UNF Pin 17.8 17.8 17.8 17.8

24.5 24.5 24.5 24.5

Weld Pitch (mm/rev)

Tilt Angle (deg)

0.23 0.34 0.45 0.56

2.5 2.5 2.5 2.5

Fig. 8 — Model results vs. experimental observations for the weld torque required while using the smooth surface FSW tool.

Fig. 9 — Model results vs. experimental observations for the weld power required while using the threaded surface FSW tool.

Fig. 10 — Model results vs. experimental observations for the weld torque required while using the threaded surface FSW tool.

Q = 2 π R k (T − T ) a

a a

(6)

0

The conduction loss to the spindle (Qs) is approximated as a linear flow of heat in a rod. Heat travels from the shear surface temperature (T) at the shoulder through a length of rod (Lsp) to a fixed ambient temperature (T0). The expression for the heat loss to the spindle is given in Equation 7. Where (ksp) and (Rsp) refer to the effective spindle thermal conductivity and radius, respectively.

Q = s

k πR sp

2

sp

(T − T ) 0

(7)

L

sp

As the tool advances during the weld, cooler material enters the front of the weld while hotter material is deposited in the wake of the weld. This gives rise to convective heat loss. The convective heat loss is dependent on the power required to heat material passing through the cross section of the shear surface from ambient to that of the shear surface. As with the case of power generation, the cross section of the pin pro-

file may be substituted to make an approximation if the shear surface profile is not known. The expression for the convective heat loss (Qv) considering a cylindrical profile is given in Equation 8. Where (2RH) describes the cross-sectional area, (V) refers to the travel velocity, and (ρc) refers to the volumetric heat capacity of the workpiece material.

Q = 2RHV ρ c (T − T ) v

0

(8)

Theoretical Estimation of the Peak Temperature

It is assumed that FSW is a steady-state process, there is no storage of energy, and the shear surface is isothermal. Additionally, it is assumed all of the mechanical power is converted into thermal energy, and efficiency factors for the loss terms are neglected. With the present assumptions, the conservation of energy is given by Equation 9.

Table 3 — Percent Difference Between the Model and Experimental Weld Power and Weld Torque

Weld Pitch (mm/rev) 0.23 0.34 0.45 0.56

Smooth Surface FSW Tool Power Torque Difference Difference (%) (%) 0.1 1.3 10.9 18.4

0.1 1.3 10.9 18.4

Threaded Surface FSW Tool Power Torque Difference Difference (%) (%) –7.3 –1.5 9.1 21.9

–7.3 –1.4 9.1 21.9

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Fig. 7 — Model results vs. experimental observations for the weld power obtained while using the smooth surface FSW tool.

B

A

D

C

Fig. 11 — Smooth surface FSW tool. A — 0.23 mm/rev; B — 0.34 mm/rev; C — 0.45 mm/rev; and D — 0.56 mm/rev, showing a loss of shoulder contact at the higher weld pitches.

WELDING RESEARCH

A

B

C

D

Fig. 12 — Threaded surface FSW tool. A — 0.23 mm/rev; B — 0.34 mm/rev; C — 0.45 mm/rev; and D — 0.56 mm/rev, showing a loss of shoulder contact at the higher weld pitches.

Q =Q +Q +Q +Q g

w

a

s

v

(9)

In addition to the relationships between the processing parameters and heat loss terms, the shear stress as a function of temperature needs to be defined. A linear approximation, Equation 10, is used that captures thermal softening with increasing temperature with a lower bound of zero flow stress at the melting temperature. In Equation 10, (mτ) is the change in shear stress with respect to temperature in the near melting regime, (Tm) is the melting temperature of the workpiece, and (T) is the shear surface temperature.

τ = m (T − T ) τ

m

(10)

Figure 4 shows macrographs of the longitudinal exit hole verifying significant shoulder contact was maintained at conditions of 0.23 and 0.34 mm/rev. Thus, the value of (mτ) was found from the torque values measured at these conditions. Since it was assumed that there was no loss of shoulder contact and sticking contact conditions were experienced for these welds, 80-s

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any reduction in the shear surface was deemed negligible. After applying the energy balance of Equation 9 and the relationship outlined in Equation 10, a theoretical expression for the shear surface temperature can be found. Equation 11 is the expression for the shear surface temperature using the cylindrical source expressions. ⎛ 2π k H ⎜ w + 2π Rk a ⎜ ⎛R ⎞ ⎜ ⎜ 0⎟ ln ⎜ ⎜R ⎟ ⎝ ⎠ ⎜ ⎜ k πR 2 ⎜ sp sp + + 2RHV ρ c ⎜ L ⎜ sp T +⎜ m ⎛ 3 ⎜ ⎜ ⎛R ⎞ H ⎜ 3⎜ 1⎜ s ⎟ + ⎜ 2mτ ωπ R ⎜3⎜ R ⎟ R ⎜ ⎜ ⎝ ⎠ ⎝ ⎜ ⎜ ⎜ ⎜ ⎜⎜ ⎝

⎞ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟T ⎞⎟ 0 ⎟⎟ ⎟⎟ ⎟⎟ ⎟ ⎠⎟ ⎟ ⎟ ⎟ ⎟⎟ ⎠

T = ________________________________ ⎞ ⎛ 2π k H ⎟ ⎜ w + 2π Rk a ⎜ ⎛ ⎞ ⎟ ⎜ ⎜ R0 ⎟ ⎟ ⎜ ln ⎜ ⎟ ⎟ R ⎜ ⎝ ⎠ ⎟ ⎜ ⎟ 2 ⎜ ksp π R sp ⎟ + 2RHV ρ c ⎜+ ⎟+1 L ⎜ ⎟ sp ⎜ ⎟ ⎜ ___________________________ ⎟ ⎜ ⎞ ⎟ ⎛ 3 ⎜ ⎜1 ⎛ R ⎞ H ⎟ ⎟ ⎜ 2 m ωπ R 3 ⎜ ⎜ s ⎟ + ⎟ ⎟ ⎜ τ ⎜3⎜ R ⎟ R ⎟⎟ ⎟⎟ ⎜ ⎝ ⎠ ⎜ ⎠ ⎠ ⎝ ⎝

(11)

Discussion and Results Based on the development of a onedimensional heat transfer model, the shear surface temperature can be theoretically calculated based on the process pa-

% Diff =

Value

model

− Value

experiment

⎛ Value ⎞ + Value model experiment ⎟ ⎜ ⎜⎜ ⎟⎟ 2 ⎝ ⎠

(12)

To evaluate the changes in accuracy of model predictions between the lower and higher values of weld pitch, macrographs were made of all longitudinal views of the

Table 4 — Percent Difference Between the Calculated and Experimental Weld Power and Weld Torque When the Shoulder Radius Is Reduced to the Pin Radius at 0.45 and 0.56 mm/rev

Weld Pitch (mm/rev) 0.23 0.34 0.45 0.56

Smooth Surface FSW Tool Power Torque Difference Difference (%) (%) 0.1 1.3 1.8 10.6

exit hole as shown in Figs. 11 and 12. At the higher weld pitches of 0.45 and 0.56 mm/rev, a loss of shoulder contact with the workpiece is observed for both the smooth and threaded surface FSW tools. If the FSW tool experiences a loss of shoulder contact, then the shearing surface decreases and less power is required to rotate the FSW tool. Repeating the model calculations and using a reduced effective shoulder radius equal to the pin radius results in better agreement at the higher weld pitches as summarized in Table 4.

Alternative Heat Index While the PHI has been used to conceptualize the heat input in a FSW, this study demonstrates its inaccuracy at maintaining a constant heat input over a range of process parameters. The constant PHI value used in this study to guide the selection of a range of processing parameters resulted in differences observed in the weld power. This is understandable as the PHI does not capture the effects of different weld tools, nor does it consider interactions with the backing anvil and spindle. To resolve this discrepancy, an AHI is proposed. Starting from the energy balance given in Equation 9, the appropriate expressions for the cylindrical FSW tool and associated heat losses are applied, and an AHI equation is formed. The utility of this equation is in its ability to predict the complementary process parameter, when one of them is varied, to maintain a constant temperature in the shear surface. It also provides the opportunity to predict process parameters to maintain a similar temperature when changing FSW tooling, e.g., anvil, spindle, etc. The expression for the AHI equation using the cylindrical terms is given in Equation 13, where (T–T0) is the temperature rise in the shear surface, and (τ) is the flow stress of the material in the shear surface. When determining process parameter changes while maintaining a constant temperature rise, the shear flow shear stress (τ) will be constant. When using the expression for an AHI the temperature rise divided by the shear flow stress becomes a constant value, that is the AHI.

Threaded Surface FSW Tool Power Torque Difference Difference (%) (%)

0.1 1.3 1.8 10.6

–7.3 –1.5 –6.4 8.5

AHI =

–7.3 –1.4 –6.5 8.6

(T − T0 ) ω =A B + C + D + EV τ

where, ⎡ ⎢ ⎛R 1 A = 2π R 3 ⎢ ⎜⎜ s ⎢3 ⎜ R ⎢⎣ ⎝

B=

⎤ ⎞3 ⎥ H ⎟ + ⎥ ⎟⎟ ⎥ R ⎠ ⎥⎦

2π kw H

R ln 0 R C = 2 π Rka D=

ksp π Rsp 2 Lsp

E = 2RH ρ c

(13)

Equation 13 can be further simplified to isolate the process parameters of spindle speed (ω) and travel velocity (V). In doing so, the expression ends up with two terms, one of which largely encompasses attributes of the FSW tool related to power generation. The other term largely encompasses the attributes related to the heat loss terms. This equivalent expression is shown in Equation 14. AHI =

(T − T ) 0

τ

=A

ω B +V

(14)

where, ⎤ ⎡ ⎛ ⎞3 π R 2 ⎢ 1 ⎜ Rs ⎟ H ⎥ ⎢ + ⎥ A= R⎥ H ρ c ⎢ 3 ⎜⎝ R ⎟⎠ p⎢ ⎥⎦ ⎣ ⎛ ⎜ π R 2 ⎜⎜ k k k sp sp a + w B= + ⎜ ⎛ ⎞ 2 ρc ⎜ 2L RH R HR sp p 2 ⎜ 0⎟ sp ⎜ R sp R ln ⎜ ⎟ ⎜ R ⎝ ⎠ ⎝

⎞ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎟ ⎠

Conclusions The initial process parameters were selected based on a constant PHI expression

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rameters, geometry of the FSW tool, and thermal properties of the workpiece and tooling. Utilizing the geometry of the smooth surface FSW tool described in Table 1 and workpiece material properties for AA2219-T87, the shear surface temperature is calculated using Equation 11 for a range of travel velocities at different weld pitches. Because direct measurements of the shear surface temperature were not obtained during this study, only the weld power can be compared. Thus, from the calculated temperature, the weld power can be determined from Equation 4 with t he corresponding specific energy obtained by dividing the weld power by the travel velocity. Figures 5 and 6 show the weld power vs. the travel velocity and the specific weld energy vs. the travel velocity, respectively, for different weld pitches. In Fig. 5, as the travel velocity is increased, the weld power also increases. These results can be explained by a conceptual heat model (Ref. 9) in which increased travel velocity brings material with a higher flow stress into the shear surface, thereby increasing the weld torque and, hence, power. These results and trends are in agreement with other published trends (Ref. 17). Figures 7 and 8 compare the weld power and weld torque, respectively, for the calculated vs. experimental values using the smooth surface FSW tool. Similarly, Figs. 9 and 10 are the same type of graphs for the threaded surface FSW tool. At the lower weld pitches, there is good agreement. The one-dimensional heat transfer model predicts increasing weld power with increasing weld pitch. Since the weld pitch is based on the ratio of travel velocity to spindle speed, this correlates with increased travel velocity. Other studies have shown a similar correlation between increases in travel velocity and increases in weld power (Ref. 17). The torque calculations predict a decrease with increased spindle speed, regardless of travel velocity, similar to other published results (Ref. 9, 18). The percent differences between the model and experimental weld power and weld torque are shown in Table 3. Equation 12 was used to calculate the percent difference with good agreement exhibited at the lower weld pitches.

WELDING RESEARCH

taken from FSW literature (Ref. 10). However, for each corresponding tool used in this study, variations were seen in the process parameter window that resulted in defect-free welds and in their weld properties. Using a one-dimensional heat transfer model, a method is proposed for calculating process parameters that takes into account the specific tool design. Certain assumptions were made in the formulation of the model that impact the model behavior and need to be taken into consideration when using the theory to explain the process of FSW. The model is based on the sticking condition and the presence of a constant shear surface area. If a significant loss of shear surface area occurs, there will inevitably be a deviation from the model calculations and experimental observations. Thus, this model can be reversely applied to determine if there is a loss of shear area, which might indicate slipping and warrant inspection of the weld. This theory is used to determine the shear surface temperature. If upper and lower bounds for this temperature are chosen, the model could conceivably be used to determine the processing parameters that will produce shear surface temperatures in that region. However, in the present form, the model cannot predict the required temperature. That will be dependent on the metallurgical properties of the material being welded. In a simplified form, the model can be used to develop an alternative heat indexing equation. This equation should allow for more accurate scaling of process parameters as it takes into consideration the effects of the FSW tool geometry and other tooling. In the simplified forms, the equations can be used to determine the corresponding process parameter, (ω) or (V), when one is changed to maintain a constant shear surface temperature. Acknowledgments The authors would like to extend their sincerest gratitude to the National Aeronautics and Space Administration’s Marshall Space Flight Center and the EM30 welding group for their assistance and use of their friction stir welding equipment. References 1. Record, J. H., et al. 2007. A look at the statistical identification of critical process parameters in friction stir welding. Welding Research: 97-s to 103-s. 2. Nunes, A. C., McClure, J., and Avila, R. 2005. The plunge phase of friction stir welding. Proc. 7th International Conference on Trends in Welding Research. Eds. S. David et al., pp. 241–245. ASM Int’l. 3. Johnson, R. 2000. Forces in friction stir welding of aluminum alloys — Further studies.

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TWI 7417.01/00/1076.3. Cambridge, UK, TWI. 4. Johnson, R., and Horrex, N. L. 2000. Preliminary examination of forces generated during the friction stir welding process. TWI 7417.01/99/1023.03. Cambridge, UK, TWI. 5. McClure, J. C. 2005. A study of forces during friction stir welding. NASA Summer Faculty Research Opportunities. Huntsville, Ala., NASA-MSFC. 6. Chimbli, S. K., Medlin, D. J., and Arbegast, W. J. 2007. Minimizing lack of consolidation defects in friction stir welds. Proc. 136th TMS Annual Meeting Friction Stir Welding & Processing IV Symposia. Eds. R. S. Mishra et al., pp. 135–142. John Wiley & Sons, Inc. 7. Stahl, A. L., and Sorensen, C. D. 2005. Experimental measurements of load distributions on friction stir weld pin tools. Proc. 134th TMS Annual Meeting Friction Stir Welding & Processing lll Symposia. Eds. R. S. Mishra et al., pp. 179–190. John Wiley & Sons, Inc. 8. Reynolds, A. P., and Tang, W. 2001. Alloy, tool geometry, and process parameter effects on friction stir weld energies and resultant FSW joint properties. Proc. 130th TMS Annual Meeting Friction Stir Welding & Processing Symposia. Eds. K. V. Jata et al., pp. 15–23. TMS. 9. Colligan, K. J. 2007. Relationships between process variables related to heat generation in friction stir welding of aluminum. Proc. 136th TMS Annual Meeting Friction Stir Welding & Processing IV Symposia. Eds. R. S. Mishra et al., pp. 39–54. John Wiley & Sons, Inc. 10. Kandukuri, S. et. al. 2007. Development of design curves for tensile strength and fatigue characteristics of 7075-T73 aluminum FSW butt

joints. Proc. 136th TMS Annual Meeting Friction Stir Welding & Processing IV Symposia. Eds. R. S. Mishra et al., pp. 29–38. John Wiley & Sons, Inc. 11. Schneider, J. A. 2006. Toward understanding the material flow path variations in friction stir weld (FSW) processes. NASA-MSFC Cooperative Agreement NNM04AA14A. Huntsville, Ala., NASA-MSFC. 12. Incropera, F. P., and Dewitt, D. P. 2002. Fundamentals of Heat and Mass Transfer. p. 53, New York, N.Y.: John Wiley & Sons, Inc. 13. Querin, J. A. 2010. Deconvoluting the link between weld tool geometry and process parameters. PhD dissertation. Mississippi State, Miss., Mississippi State University. 14. Schmidt, H., Hattel, J., and Wert, J. 2004. An analytical model for the heat generation in friction stir welding. Modelling and Simulation in Materials Science and Engineering 12: 143–157. 15. Nunes, A. C. 2001. Wiping metal transfer in friction stir welding. Proc. 130th TMS Annual Meeting Automotive Alloys and Joining Aluminum Symposia. Eds. S. K. Das, J. G. Kaufman, and T. J. Lienert, pp. 235–248. TMS. 16. Nunes, A. C. 2006. Metal flow in friction stir welding. Proc. Materials Science and Technology 2006 Conference Friction Stir Welding II Symposia. pp. 107–118. John Wiley & Sons, Inc. 17. Mishra, R., and Mahoney, M. 2007. Friction Stir Welding and Processing. p. 60, Materials Park, Ohio: ASM Int’l. 18. Colligan, K. J., and Mishra, R. S. 2008. A conceptual model for the process variablesrelated to heat generation in friction stir welding of aluminum. Scripta Materialia 58: 327–331.

AWS Debuts Careers in Welding Trailer The AWS Careers in Welding Trailer offers many attractive features to get young people excited about welding industry careers. In particular, the mobile exhibit showcases the following: • Five of The Lincoln Electric Co.’s VRTEX® 360 welding simulators that feed computer-generated data with a virtual welding gun and helmet equipped with internal monitors; • Interactive educational exhibits, including a display wall featuring 11 industry segments with trivia questions, fun facts, and industry artifacts; • “Day in the Life of a Welder” exhibit with videos depicting real-life environments in which welders work; • Life-size welder highlighting welding as a safe profession; • Social media kiosk; and • Welding scholarship information. The 53-ft, single expandable trailer designed and built by MRA experiential tours and equipment covers 650-sq-ft of exhibit space. It is expected the trailer will be on the road for 18–24 weeks in 2012. To learn more and view its schedule, visit www.explorewelding.com.

Improving Supermartensitic Stainless Steel Weld Metal Toughness Eliminating ferrite, maximizing austenite, and softening martensite through PWHT markedly improved toughness with respect to the as-welded condition

ABSTRACT Welding of supermartensitic stainless steel plays a crucial role in fabricated components, influencing their toughness, weldability, and resistance to sulphide stress cracking. Postweld heat treatment adjusts the final properties of the weldments, bearing on microstructural evolution. The objective of this work was to maximize all-weldmetal toughness by microstructural modifications achieved by means of postweld heat treatments (PWHTs). Two all-weld-metal test coupons were prepared according to standard ANSI/AWS A5.22-95, using a 1.2-mm-diameter tubular metal-cored wire under Ar-5%He and Ar-18%CO2 gas shielding mixtures in the flat position, with a nominal heat input of 1.6 kJ mm-1. Single tempering, solution annealing, solution annealing plus single tempering, and solution annealing plus double tempering treatments were carried out at different times and temperatures. All-weld-metal chemical composition analysis, metallurgical characterization, hardness and tensile property measurements, and Charpy V tests were carried out. It was found that eliminating ferrite, maximizing austenite, and softening martensite through PWHT, improved toughness up to almost three times with respect to the as-welded condition, for both shielding gases used. When welding under Ar-18%CO2 shielding gas, the following was detected: a) higher all-weld-metal contents of C, O, and N and slightly lower contents of Mn, Si, Cr, Ni, Mo, Cu; this fact produced slightly lower ferrite and austenite contents in the as-welded condition and b) lower toughness and ductility, and higher strength and hardness, regarding the samples welded under Ar-5%He mixture.

Introduction Supermartensitic stainless steels (SMSS) have been developed in the last years as attractive technical alternatives to high-strength low-alloy (HSLA) steels mainly in applications related to the oil and gas industry (Refs. 1, 2). Welding of these materials plays a crucial role in fabricated components, influencing their toughness, weldability, and resistance to S. ZAPPA ([email protected]) is with Research Secretariat, Faculty of Engineering, University of Lomas de Zamora, Buenos Aires, Argentina. H. G. SVOBODA is with Materials and Structures Laboratory, Faculty of Engineering, Intecin, University of Buenos Aires, CONICET, Buenos Aires, Argentina. N. M. RAMINI DE RISSONE is with Deytema, Regional Faculty of San Nicolás, National Technological University, San Nicolás, Argentina. E. S. SURIAN is with Research Secretariat, Faculty of Engineering, University of Lomas de Zamora, Buenos Aires, and Deytema, Regional Faculty of San Nicolás, National Technological University, San Nicolás, Argentina. L. A. DE VEDIA is with Institute Sabato — National University of San Martín — Atomic Energy Commission, San Martín, Buenos Aires, Argentina.

sulfide stress cracking. Supermartensitic stainless steels were developed based on classic martensitic stainless steels (11–14% Cr), reducing C content to enhance weldability and corrosion resistance and adding Ni to promote a free-ferrite structure and Mo (Refs. 3, 4), which also improves corrosion resistance (Refs. 5, 6). Depending on chemical composition and welding procedure, the microstructure of SMSS deposits obtained in the aswelded condition is mainly composed of martensite with variable fractions of austenite (up to 30%) and ferrite (up to 10%), with different morphologies (Ref. 7). Postweld heat treatment (PWHT) is

KEYWORDS Supermartensitic Stainless Steel Welding Procedure Postweld Heat Treatment Toughness

usually necessary to adjust weldment properties, based on microstructural evolution. In the as-welded condition, it is common to obtain high hardness and low toughness, due to the presence of untempered martensite (Refs. 6, 8). In practice, PWHTs used involve single or double tempering treatments, promoting martensite tempering and formation of retained austenite, which results in lower hardness and higher toughness values (Refs. 4, 9). Nevertheless, these PWHTs are a considerable cost and time-consuming step in pipe welding, then in new SMSS, chemical composition has been modified to avoid PWHT or to minimize it to shorter times, less than half an hour (Ref. 10). For welding these materials, the gas metal arc welding (GMAW) process using SMSS metal cored wires has been recognized as a suitable technological option, and its use has recently been improved (Ref. 4). This type of consumable presents several advantages such as low slag generation and high deposition rate (Ref. 11). Shielding gases employed for welding this type of material usually are inert mixes (Ar-He) or Ar-rich mixtures (Ar-CO2, ArCO2-O2) with a very low amount of active gases (less than 5%) (Ref. 12). The type of shielding gas can affect the chemical composition of the weld metal, principally O, N, and C contents (Ref. 13). There have been many efforts to develop tougher SMSS deposits. Control of chemical composition, particularly reducing C, O, N, and S contents or addition of Ni, has proved to be successful (Ref. 10). Besides, it is well known that the content of low toughness phases like untempered martensite or ferrite affects the final value of toughness, as well as an increased fraction of retained austenite improves it (Ref. 3). The role of precipitation reactions is not yet completely understood. Different PWHTs lead to microstructural modifications producing different combinations of phases present in SMSS weld deposits (tempered and untempered martensite, austenite, carbides, etc.), with each microstructural pattern affecting toughness in a specific way.

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BY S. ZAPPA, H. G. SVOBODA, N. M. RAMINI DE RISSONE, E. S. SURIAN, AND L. A. DE VEDIA

Fig. 3 — Macrography of AHaw sample.

Fig. 1 — Transverse cross section for chemical analysis, microstructural characterization, and microhardness determination. (Dimensions in mm.)

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To analyze the effect of shielding gas, transverse cross sections for chemical analysis were extracted from each coupon. AWM chemical compositions were determined by means of spectrometric measurements except C, N, O, and S contents that were analyzed via LECO™.

Fig. 2 — Tension test and Charpy V location.

The objective of this work was to systematically study the effect of different microstructural patterns of all-weld-metal (AWM) SMSS on toughness in order to improve this property. Additionally, the effect of interstitial elements content on toughness was evaluated, giving consideration to the shielding gas used.

Experimental Procedure Welding

Two AWM test coupons were welded according to standard ANSI/AWS A5.22-95 (Ref. 14) using a metal cored tubular wire of 1.2 mm diameter, obtaining a SMSS weld deposit using the GMAW process with two different shielding gases. The welding parameters are presented in Table 1. The welding position was flat; preheating and interpass temperatures were 100°C. The shielding gas flow rate was 18 L/min and the stickout 20 mm. A power source with pulsed arc of 120 Hz was employed. Both welded coupons were evaluated by radiographic testing according to ANSI B31.3 standard (Ref. 15).

Chemical Composition

Postweld Heat Treatments

To induce different microstructural conditions, samples of each coupon were submitted to the different heat treatments shown in Table 2 with the corresponding sample identification. As shown in Table 2, different PWHTs consisting of a) single tempering (650); b) solution annealing (1000); c) solution annealing plus single tempering (1000 + 650); and d) solution annealing plus double tempering (1000 + 650 + 600) were conducted maintaining as reference the as-welded condition. The PWHT parameters were selected according to previous information (Refs. 3, 8, 16) with the purpose of softening the martensite matrix, minimizing the ferrite content, and maximizing the austenite content, in order to improve AWM toughness. The overall objective was to allow the analysis and understanding of the influence of each phase present. Single and double tempering treatments soften martensite (Ref. 17) and modify the austenite content, depending on treatment temperature and time (Refs.

Table 1 — Welding Parameters Identification

Shielding Gas

Tension (V)

Current (A)

Welding Speed (mm s-1)

Heat Input (kJ mm-1)

AH AC

Ar-5%He Ar-18%CO2

29 30

298 301

5.0 5.5

1.73 1.64

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8, 18). Solution annealing between 950° and 1050°C allows the dissolution of both ferrite and austenite (Ref. 18). Microstructural Characterization

Microstructural characterization was done using light (LM), scanning electron (SEM) microscopy, and X-ray diffraction (XRD). Ferrite contents were measured following standard ASTM E562-99 (Ref. 19) by quantitative metallography and austenite contents by means of the direct peak comparison method, based on XRD patterns (Ref. 20). Dilatometric analysis has been made for AHaw and ACaw samples, to achieve a better understanding of phase transformations that take place during PWHT. Transformation temperatures AC1, AC3, and MS were determined with a heating/cooling rate of 10°C/min. Mechanical Properties

Vickers 1 kg microhardness (HV1) measurements as well as Charpy V-notch (CVN) tests (Ref. 21) at 20°C were carried out for all conditions analyzed. Microhardness values were the average of at least five measurements. Charpy V-notch values were the average of at least three tested specimens. Transverse AWM tensile specimens (Ref. 22) were obtained for all conditions. All measurements were conducted in the central zone, in correspondence with the location of the notch of Charpy V specimens. Figures 1 and 2 present dimensions and locations of samples for different tests (Refs. 21, 22).

Results and Discussion Chemical Composition

Table 3 shows the AWM chemical composition results. The values are expressed in weight percent (wt-%), except for N and O, which are in parts per million (ppm). Samples welded under Ar-CO2 shielding showed higher contents of C, N, and O, as well as lower contents of Mn, Si, Cr, Ni, Mo, and Cu, than those welded under ArHe mixture.

A

B

Variations observed in the metallic element contents were related to oxidation processes in the arc due to a higher oxidation potential of the shielding gas (Ref. 23). Higher contents of interstitial elements could be related to higher partial pressures of O and C in the arc atmosphere due to decomposition of CO2 (Ref. 24). To obtain good mechanical properties, these steels must have very low C content (0.010%) and high values of Ni (6.5%) and Mo (2.5%) (Ref. 25), together with very low levels of detrimental elements like N, O, and S (Refs. 7, 26), because they strongly affect hardness and toughness (Refs. 3, 26). The variations observed in chemical composition could affect properties of the weld deposits. As mentioned before, C content in coupon AC (0.022%) was higher than the nominal value of 0.010% (Refs. 26, 27) reported by the consumable manufacturer; this could have led to higher hardness and lower toughness values compared to coupon AH. Coupon AC presented unexpected significantly higher O and N contents with respect to coupon AH. It has been reported that O values higher than 300 ppm, as well as a high N content, produce a strong detrimental effect on toughness (Refs. 5, 7). It was expected that mechanical properties, metallurgical aspects, and transfor-

A

B

C

D

Fig. 5 — LM microstructures of samples welded under Ar-He shielding: A — AH650; B — AH1000; C — AH1000 + 650; D — AH1000 + 650 + 600.

mation temperatures could also be affected by the observed Cr, Ni, Mo, Mn, and Cu variations. For these steels, retained austenite contents between 2 and

30% have been reported (Refs. 5, 7, 8). Ni, Cu, and Mn are known as austenite stabilizers; therefore, a higher content of these elements could increase retained austen-

Table 3 — AWM Chemical Composition Element

AH

AC

C Mn Si Cr Ni Mo Cu V Nb S P O (ppm) N (ppm)

0.012 1.76 0.44 12.1 6.27 2.69 0.49 0.09 0.01 0.013 0.015 390 50

0.022 1.61 0.40 11.9 5.98 2.57 0.43 0.09 0.01 0.014 0.015 610 260

Table 2 — Identification of Samples and PWHT Parameters Identification AHaw AH650 AH1000 AH1000 + 650 AH1000 + 650 + 600 ACaw AC650 AC1000 AC1000 + 650 AC1000 + 650 + 600

PWHT Temperatures (°C)

Time (min)

None 650 1000 1000 + 650 1000 + 650 + 600 None 650 1000 1000+650 1000 + 650 + 600

None 15 60 60 + 15 60 + 15 + 15 None 15 60 60 + 15 60 + 15 + 15

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Fig. 4 — LM columnar zone microstructure of the following samples: A — AHaw; B — ACaw.

Table 4 — Ferrite and Austenite Contents Sample

A

B

Ferrite (%) Austenite (%)

AHaw AH650 AH1000 AH1000 + 650 AH1000 + 650 + 600 ACaw AC650 AC1000 AC1000 + 650 AC1000 + 650 + 600

10 10 0 0 0 6 6 0 0 0

20 15 0 12 21 18 7 0 18 19

Table 5 — Cr and Ni Equivalents

D

C

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Fig. 6 — LM microstructures of samples welded under Ar-CO2: A —AC650; B — AC1000; C — AC1000 + 650; D —AC1000 + 650 + 600.

ite percentages (Refs. 3, 8). Furthermore, Cr and Mo stabilize ferrite and a higher content of this phase is produced if these elements are increased (Refs. 3, 8). Microstructural Characterization

Radiographic testing was evaluated with ANSI B31.3 (Ref. 15) resulting in a low level of defects. Figure 3 shows the AWM macrostructure obtained for sample AHaw. Figure 4 shows the columnar zone microstructures for the AHaw and ACaw samples. In both cases, martensite with low fractions of ferrite was detected, as was reported previously (Refs. 1, 3, 7, 8, 12). There was no observable effect of shielding gas on the microstructure. Two types of ferrite could be identified based on their location and morphology. Most common was ferrite with morphology similar to that of the ferrite found in duplex stainless steel weld metals. The presence of this ferrite is a consequence of incomplete ferrite-to-austenite transformation in weld metals solidifying as ferrite and was most common for more highly alloyed weld metals (Ref. 7). Another ferrite morphology, similar to that seen in austenitic stainless steel weld metals, was found in the weld metals highest in Ni solidifying as a mixture of ferrite and austenite (Ref. 7). This ferrite was located in the last solidifying interdendritic regions. Figures 5 and 6 show microstructures for different PWHT conditions of coupons welded under Ar-He and ArCO2, respectively. 86-s

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There were no observable differences between the LM microstructures of both coupons for the different PWHTs. For AH650 and AC650 the microstructure did not change, showing a slight darkening associated with a precipitation phenomena. Solution annealing produced ferrite solubilization, and the microstructures that resulted were completely martensitic. Solution annealing followed by single and double tempering produced a severe darkening in the microstructure associated with carbide precipitation. As mentioned previously, retained austenite is reported for these steels in the as-welded condition (Ref. 7). This phase was not observable by means of the microscopy techniques used in this work (Refs. 7, 8), but was detectable using the XRD technique. The XRD patterns obtained for different PWHT conditions, showing the martensite/ferrite and austenite peaks, are presented in Figs. 7, 8. It can be seen for both as-welded samples that there was a fraction of retained austenite that diminished with the single tempering treatment and vanished after solution annealing. The single and double tempering treatments after solution annealing increased the retained austenite content, as was to be expected (Ref. 28). Table 4 shows the results of ferrite and austenite content quantification for the analyzed conditions. Coupon AHaw showed higher contents of both ferrite and austenite than coupon ACaw. To relate the as-welded samples’ ferrite and austenite contents to the chemical composition, the expressions of Cr and Ni

Condition

Cr eq

Ni eq

AHaw ACaw

25.5 24.6

29.8 29.5

Table 6 — Transformation Temperatures Condition

AC1 (°C)

AC3 (°C)

Ms (°C)

AHaw ACaw

580 640

640 710

130 125

equivalents developed by Karlsson et al. (Refs. 29, 30) for SMSS were employed in this work. Table 5 shows the results of Cr and Ni equivalents for both welding conditions. There were no significant variations in the calculated values. However, microstructure showed martensite and ferrite for the ACaw condition and martensite, ferrite and austenite for the AHaw condition, related to a higher Cr equivalent in this last sample — Fig. 9. This fact could explain the slightly higher austenite and ferrite contents measured for condition AHaw as compared to ACaw. It was previously reported that ferrite deteriorates toughness and austenite improves this property (Ref. 31). Indeed, toughness is improved by a low-carbon soft martensite (Ref. 31). In this sense, PWHT, which minimizes ferrite, maximizes austenite, and softens martensite, could provide the best results (Ref. 31). Martensite tempering is produced during PWHT of these steels. In general, this allows martensite softening, associated with incoherent carbide precipitation, to reach the maximum softening with the precipitation of M23C6 carbides at temperatures over 500°C (Ref. 32). In Ni-free alloys, PWHTs are performed at temperatures over 700°C to obtain a high reaction rate and maximum softening. Nevertheless, the presence of Ni reduces the critical temperature (AC1). This temperature depends on chemical composition and heating rate, but with high Ni content it

Fig. 8 — XRD patterns for samples welded under Ar-He protection, with different PWHTs.

Fig. 9 — AHaw and ACaw sample locations in Karlsson et al. (Ref. 7) constitution diagram for SMSS (M: martensite; A: austenite; F: ferrite).

Fig. 10 — Relationship between microhardness and tensile and yield strengths.

could be as low as 500°–550°C (Ref. 32). At this temperature, the carbides’ formation kinetics is very slow and under these conditions, it is normal that PWHT produces austenite for alloys 13Cr-4Ni (Ref. 32) with a different chemical composition from that of the austenite retained during welding (Refs. 32, 33). Austenite formed during PWHT will be rich in Ni, C, and Mn. The degree of enrichment will determine the stability of the austenite formed. If the PWHT is performed at temperatures slightly over AC1, enriched austenite will be stable at ambient temperature. If the PWHT temperature is sufficiently higher than AC1, the austenite formed will transform to untempered martensite during cooling (Ref. 32). In Table 6, results of transformation temperature (AC1, AC3, and MS) determinations for each coupon, using a heating rate of 10°C/min, can be seen. Critical temperatures (AC1 and AC3) of the specimen ACaw were higher than those of specimen AHaw. It is known that these temperatures are heavily controlled by the chemical composition, then the changes observed could be explained in terms of

the higher alloy content of coupon AHaw that produced a decrease in the transformation temperatures (Ref. 7). In both cases, single tempering slightly reduced the austenite content, through partial transformation of austenite to martensite. Lippold and Alexandrov (Ref. 17) showed that variations of 20° to 300°C/min

in heating rate produced an increase in AC1 of more than 100°C. A tempering heat rate of 300°C/min was used in this work. Therefore, an increased AC1 could be expected when tempering at 650°C, resulting in a subcritical temperature treatment. In this condition, a decrease in austenite content could be achieved.

Table 7 — Tensile Test Results Sample AHaw AH650 AH1000 AH1000+650 AH1000+650+600 ACaw AC650 AC1000 AC1000 + 650 AC1000 + 650 + 600

σUTS(a) (MPa)

σ0.2(b) (MPa)

ε(c) (%)

H(d) (HV1)

1048 941 986 954 941 1107 990 1008 982 963

838 790 770 698 712 885 821 756 745 707

15.7 17.0 20.0 27.5 29.4 12.5 13.0 16.8 17.3 18.8

324 322 318 305 293 348 338 338 313 304

(a) — σUTS: ultimate tensile strength (b) — σ0.2: yield strength (c) — ε: elongation (d) — H: hardness

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Fig. 7 — XRD patterns for samples welded under Ar-CO2 protection, with different PWHTs.

Fig. 12 — Absorbed energy at 20°C (J) vs. Vickers microhardness (HV1).

Fig. 11 — Relationship between elongation and hardness.

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Solution annealing treatment was effective to dissolve both ferrite and retained austenite; it also produced a decrease in segregation with the matrix enrichment of the elements before being segregated (Ref. 33). The mentioned enrichment of the matrix could have generated a diminution of the AC1 with what the first tempering temperature after SA could have been inside the intercritical temperature zone. This fact could justify the apparition of retained austenite. Finally, the posterior treatment at 600°C (samples AH1000 + 650 + 600 and AC1000 + 650 + 600) generated a microstructure composed of tempered martensite and a higher proportion of austenite, without ferrite. The mechanism by which the austenite content was enhanced with a double tempering could be explained by means of the thermal instabilities of austenite particles during cooling of the first tempering, according to a previous report (Ref. 3). Stability of austenite is associated with both chemical and structural factors related to a high dislocation density in the substructure. In the first tempering at 650°C (after SA), the austenite content formed during heating was increased and partially transformed

to fresh martensite during cooling. At this temperature, thermal activation could have been enough to promote recovery mechanisms that allowed annihilation of dislocations, reducing the dislocation density into the austenite particles, transforming them into martensite during cooling from 650°C. After SA + 650 treatments, the microstructure was composed by tempering martensite, fresh martensite, and retained austenite. During the second tempering at 600°C (SA + 650 + 600), new austenite preferentially nucleated at the higher interfacial area recently created, and therefore, a higher amount of austenite particles were formed. It is assumed that this austenite was formed by a shear mechanism and had a high dislocation density, which did not suffer alterations at this temperature. Indeed, untempered martensite was tempered, resulting in a soft martensite matrix with uniform distributed austenite particles (Ref. 34).

Mechanical Properties Table 7 presents hardness and tensile test results of all samples. These values were consistent with those reported previously for these types of materials (Refs. 8, 27). Higher values of hardness were detected for

Table 8 — Vickers Hardness and Absorbed Energy in Charpy V Impact Test Sample

H(a) (Hv1)

AE 20°C(b) (J)

AHaw AH650 AH1000 AH1000 + 650 AH1000 + 650+ 600 ACaw AC650 AC1000 AC1000 + 650 AH1000 + 650 + 600

324 322 318 305 293 348 338 338 313 304

33 55 59 75 83 24 50 32 67 75

(a) — H: Vickers hardness (b) — E: absorbed energy in Charpy V-notch impact test at 20°C

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samples welded with CO2 in the shielding gas. This effect could be related to higher contents of C and N in this sample, which produced a hardness increase (Ref. 3). With regard to PWHT, softening was observed in heat-treated samples. This could be related to the tempering of martensite and, in the case of sample AH, to a higher amount of austenite (Refs. 3, 35, 36). Yield and tensile strengths were slightly higher for the specimens welded under Ar-CO2, probably associated with their higher carbon content. Figure 10 shows an approximately linear relationship between both yield and tensile strength values and hardness determinations. Ductility was lower for specimen AC compared to sample AH. This fact could be related to the AC sample’s higher values of C, N, and O, which limit ductility. Postweld heat treatment produced a reduction in strength values with a marginal improvement in ductility, as expected (Refs. 8, 18). Figure 11 presents the relationship between elongation and hardness, which showed that an increment in hardness produced a decrease in ductility. For the same hardness values, ductility in the AH samples was higher than in the AC ones. This could be related to the higher content of interstitial elements in these samples. Table 8 presents the results obtained from Charpy V impact tests. Higher toughness was associated with lower hardness, as expected (Ref. 37). Shielding gas used during welding affected SMSS AWM toughness. With the Ar-CO2 mixture, values of absorbed energy were lower for all the conditions studied. This fact could be associated with the higher contents of C, N, and O of samples welded under Ar-CO2, as mentioned previously (Refs. 26, 38). All the PWHTs improved toughness in both cases. Single tempering without SA enhanced the absorbed energy, almost duplicating the obtained values for both conditions, although the austenite fraction was reduced and there were no changes in ferrite content. This indicates that

A

B

Fig. 13 — A — Fracture surface of sample AC650; B — typical dimples in the fracture surface of sample AC1000 + 650 + 600.

seen, this one from the AC650 sample. This typical dimple appearance showed a ductile-dimple fracture associated with a high microvoid density. This may be attributed to the existence of a large number of internal interfaces due to both nonmetallic inclusions and austenite and/or transformed austenite particles, which may act as void nucleation sites, according to previous reports for similar materials (Ref. 28). Figure 13B shows typical dimples with austenite and/or transformed austenite small particles (Ref. 28).

Conclusions • Eliminating ferrite, maximizing austenite, and softening martensite in SMSS weld metal improved toughness up to almost three times with respect to the AW condition, for both shielding gases used. The mechanisms that explained this toughness improvement were discussed. • When Ar-18%CO2 shielding gas was employed instead of Ar-5%He shielding gas, higher contents of C, O, and N and slightly lower contents of Mn, Si, Cr, Ni, Mo, and Cu were detected. This variation in chemical composition produced slightly lower ferrite and austenite contents in the as-welded condition. Lower toughness and ductility, and higher strength and hardness were obtained when this shielding gas mixture was employed. • Further studies are necessary to associate the heating rate during the PWHT, the critical temperatures of transformation, and PWHT temperatures with the stability of austenite. The present work contributes to the better comprehension of the mechanisms involved in the toughness control of SMSS deposits, considering the effects of microstructure and some aspects of the welding procedure.

Acknowledgments

The authors wish to express their gratitude to ESAB-Sweden for the donation of the consumable and for LECO chemical analysis; Conarco-ESAB-Argentina for performing chemical analysis; Air Liquide Argentina for donating gases for welding; Latin American Welding Foundation, Argentina, for facilities for welding and mechanical testing; Scanning Electron Microscopy Laboratory of INTI-Mecánica, Argentina, for facilities for SEM analysis; and APUEMFI, Argentina and ANPCyT, Argentina, for financial support. References 1. Marshall, A. W., and Farrar, J. C. M. 1998. Welding of ferritic and martensitic 13%Cr steels. Preliminary report (draft 2). IIW Doc IX-H-422-98: 1 to 18. 2. Farrar, J. C., and Marshall, A. W. 1998. Supermartensitic stainless steel — overview and weldability. IIW Doc No. IX-H 423-98: 1–3. 3. Bilmes, P. D. 2000. Role of austentite on mechanical properties of soft martensitic stainless steel weld metals. PhD dissertation. La Plata, Argentina. Universidad Nacional de La Plata, Facultad de Ingeniería. 4. Lippold, J. C., and Kotecki, D. J. 2005. Welding Metallurgy and Weldability of Stainless Steels. John Wiley & Sons, Inc. 5. Karlsson, L., Rigdal, S., Sweden, G., Bruins, W., and Goldschmitz, M. 1999. Development of matching composition supermartensitic stainless steel welding consumables. Svetsaren No. 3: 3–7. 6. Kvaale, P. E., and Olsen, S. 1999. Experience with supermartensitic stainless steels in flowline applications. Stainless Steel Word. The Hague, The Netherlands. 7. Karlsson, L., Bruins, W., Gillenius, C., Rigdal, S., and Goldschmitz, M. 1999. Matching composition supermartensitic stainless steel welding consumables. Supermartensitic Stainless Steels ‘99. Brussels, Belgium. 8. Zappa, S., Svoboda, H., Ramini de Ris-

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martensite softening was the controlling factor in this case. Solution annealing also improved toughness for both conditions. This fact could show the effect of ferrite on this property. Some degree of martensite softening could also have occurred. For coupons welded under the Ar-He mixture, this effect was more important, consistent with the higher content of ferrite in the AW condition. With single and double tempering after solution annealing, toughness was improved again; in this case 250 and 310% regarding the AHaw and the ACaw conditions, respectively. This could be associated with the softening of martensite, the absence of ferrite, and the finely dispersed austenite particles formed during these treatments (Ref. 39). These fine austenite precipitates promoted ductile fracture, enhancing the plastic work for fracture (Ref. 18). It was also reported (Ref. 39) that during fracture propagation in the Charpy V test, a mechanical transformation of austenite particles by localized transformation-induced plasticity mechanisms is generated, increasing the absorbed energy. Figure 12 presents the absorbed energy in Charpy V test vs. Vickers hardness. For both conditions, AH and AC, it was observed that as hardness increased, toughness decreased. However, a displacement of the AC curve to the right was observed. This effect could be related to the AC sample’s higher O content, which produced a decrease in toughness according to what was previously reported for this type of material (Refs. 5, 30). Regarding the fracture mode, it is worth mentioning that all specimens tested at room temperature displayed 100% of fibrous fracture with typical dimples and without cleavage. Figure 13A is representative of the fracture surfaces

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sone, M., Surian, E., and de Vedia, L. 2007. Effect of post weld heat treament on the properties of a supermartensitic stainless steel deposited with tubular metal-cored wire. Soldagem & Inspecão 12(2): 115–123. 9. Bilmes, P. D., Llorente, C. L., and Solari, M. 1998. Effect of postweld heat treatment on the microstructure and mechanical behavior of 13Cr-4NiMoL and 13Cr-6NiMoL weld metals. The 18th ASM Heat Treating Society Conference and Exposition. Chicago, Ill. 10. Akselsen, O. M., Rorvik, G., Kvaale, P. E., and Van der Eijk, C. 2004. Microstructureproperty relationships in HAZ of new 13% Cr martensitic stainless steel. Welding Journal 83(5): 160–167. 11. Lyttle, K. 1996. Metal cored wires: Where do they fit in your future? Welding Journal 74(10): 35–38. 12. Karlsson, L., Rigdal, S., Van den Broek, J., Goldschmitz, M., and Pedersen, R. 2002. Welding of supermartensitic stainless steels. Recent developments and application experience. Svetsaren No 2:15–22. 13. Zappa, S., Svoboda, H., Ramini de Rissone, M., Surian, E., and de Vedia, L. 2006. Effect of shielding gas on the supermartensitic stainless steel all weld metal properties. CONAMET/SAM 2006. Santiago de Chile, Chile. 14. ANSI/AWS A5.22-95, Specification for Stainless Steel Electrodes for Flux Cored Arc Welding and Stainless Steel Flux Cored Rods for Gas Tungsten Arc Welding. 1995. Miami, Fla.: American Welding Society. 15. ANSI B31.3-96, Chemical Plant and Petroleum Refinery Piping. 1996. New York, N.Y.: American National Standards Institute. 16. Bilmes, P. D., Llorente, C., Desimoni, J., and Mercader, R. 1997. Microstructure and properties of soft martensitic stainles steel weld metals. 2do Congresso Internacional de Tecnología Metalúrgica e de Materiais. São Paulo, Brazil. 17. Lippold, J., and Alexandrov, B. 2004. Phase transformation during welding and postweld heat treatment of a 12Cr-6.5Ni-2.5Mo su-

permartensitic stainless steel. Stainless Steel World 2004. Houston, Tex. 18. Bilmes, P. D., Llorente, C., Desimone, J., Mercader, R., and Solari, M. 1998. Microstructure and properties of 13% Cr - 4% NiMo martensitic stainless steel FCAW weld metals.. II Encuentro de Ingeniería de Materiales. La Habana, Cuba. 19. ASTM E562-99, Standard Test Method for Determining Volume Fraction by Systematic Manual Point Count. 1999. West Conshohocken, Pa.: ASTM International. 20. Cullity, B. D., and Stock, S. R. 2001. Elements of X-Ray Diffraction. New Jersey, Prentice-Hall. 3rd Edition. 21. ASTM E23-05, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials. 2005. West Conshohocken, Pa.: ASTM International. 22. ASTM E8-04, Standard Test Methods for Tension Testing of Metallic Materials. 2004. West Conshohocken, Pa.: ASTM International. 23. Vaidya, V. 2002. Shielding gas mixtures for semiautomatic welds. Welding Journal 81(9): 43–48. 24. Stembacka, N., and Persson, K. A. 1989. Shielding gases for gas metal arc welding. Welding Journal 68(11): 41–47. 25. Gough, P. C., Farrar, J. C. M., and Zhang, Z. 1999. Welding consumables for supermartensitic stainless steels. Supermartensitic Stainless Steel ‘99. Brussels, Belgium. 26. Karlsson, L., Rigdal, S., Dhooge, A., Deleu, E., Goldschmitz, M., and Van den Broek, J. 2001. Mechanical properties and ageing response of supermartensitic weld metals. Stainless Steel Word 2001. The Hague, The Netherlands. 27. Technical Sheet OK Tubrod. 2004. 15-55 ESAB. 28. Bilmes, P. D., Solari, M., and Llorente, C. L. 2001. Characteristics and effect of austenite resulting from tempering of 13Cr-NiMo martensitic steel weld metals. Materials Characterization 46: 285–296. 29. Karlsson, L., Rigdal, S., Dyberg, P., Van

den Broek, J., and Goldschmitz, M. 2002. Submerged arc welding of supermartensitic stainless steel: Good as welded toughness — realistic or not? Supermartensitic 2002. Houston, Tex. 30. Karlsson, L., Rigdal, S., Bruins, W., and Goldschmitz, M. 1999. Efficient welding of supermartensitic stainless steels with matching composition consumables. Stainless Steel Word 1999. The Hague, The Netherlands. 31. Bilmes, P. D., Llorente, C. L., and Ipiña, J. P. 2000. Toughness and microstructure of 13Cr4NiMo high strength steel welds. Journal of Materials Engineering and Performance 9(6): 1–19. 32. Gooch, T. G., Woollin, P., and Haynes, A. G. 1999. Welding metallurgy of low carbon 13% chromium martensitic steels. Supermartensitic Stainless Steel. Brussels, Belgium. 33. Folkhard, H. 1988. Welding Metallurgy of Stainless Steels. Springer-Verlag Wien, New York. 34. Bilmes, P. D., Llorente, C. L., and Solari, M. 2000. Role of the retained austenite on the mechanical properties of 13Cr-4NiMo weld metals. The 20th ASM Heat Treating Society. St. Louis, Mo. 35. Bilmes, P. D., Llorente, C., Saire Huamán, L., Gassa, L. M., and Gervasi, C. A. 2006. Microstructure and pitting corrosion of 13CrNiMo weld metals. Corrosion Science 48: 3261–3270. 36. Marshall, A. W., and Farrar, J. C. M. 2001. Welding of ferritic and martensitic 11–14% Cr steels. Welding in the World 2001 Vol. 45 (5/6): 32–55. 37. Ramirez, J. E. 2007. Weldability evaluation of supermartensitic stainless steels. Welding Journal 86(5): 125-s to 134-s. 38. Bonnefois, B., Coudreuse, L., Toussaint, P., and Dufrane, J. J. 2002. Development in GMAW of new martensitic stainless steels. Supermartensitic 2002. Houston, Tex. 39. Bilmes, P. D., Llorente, C., and Solari, M. 1999. Effect of post weld heat treatment on 13%Cr4NiMo steel FCAW deposit. X Congreso Argentino de Soldadura — VI Congreso Iberoamericano de Soldadura. Buenos Aires, Argentina.

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Ultrasonic Wave Assisted GMAW A novel method adds ultrasonic wave to provide an additional force to detach the droplet

ABSTRACT A novel modification to conventional gas metal arc welding (GMAW) was developed by applying ultrasonic wave to the welding process, referred to as UGMAW. One of the effects was ultrasonic radiation force. The principle of the proposed method is to apply the ultrasonic radiation force to droplets as an extra detaching force. To prove the feasibility of this idea, comparative experiments were conducted to uncover the basic characteristics of the metal transfer process. It was found that droplets in conventional GMAW were approximately spherical, while deformation of the droplets was observed in U-GMAW. More specifically, the droplet was elongated and its size was reduced. As a result, the metal transfer frequency increased in all experimental conditions. Analytical results show that an additional force was brought into the metal transfer process. The additional force was ultrasonic radiation force and its value was on the order of 10–3 N.

Introduction Gas metal arc welding (GMAW) is one of the most widely used industrial welding methods, preferred for its high productivity. A continuous and consumable wire electrode is fed through a welding gun, making it well suited to semiautomatic or automatic welding applications. The wire electrode plays the roles of heat source and liquid filler metal. The manner in which the liquid metal transfers from the electrode to the weld pool is referred to as metal transfer mode. It is the most important feature of GMAW and plays a significant role in determining the welding process stability and weld quality (Ref. 1). There are three basic metal transfer modes: short-circuiting, globular, and spray (Ref. 2). These metal transfer modes show different arc stabilities, weld formation, spatter levels, and so on. Shortcircuiting transfer encompasses the lowest range of welding currents and voltages. The arc length is relatively short, and the droplet cannot transfer until it touches the weld pool. The small, fast-freezing weld pool produced by the short-circuiting transfer and its associated low heat input are suitable for joining thin materials. When the welding currents and voltages are slightly higher Y. Y. FAN, C. L. YANG, S. B. LIN ([email protected]), C. L. FAN, and W. G. LIU are with the State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, China.

than that used in short-circuiting transfer, globular transfer can be achieved. The drop size is greater than the diameter of the welding wire, and the detachment is mainly controlled by gravity. When the welding current further increases to a higher level that is above a critical value called the “transition current,” transfer occurs in the form of relatively small drops that are transferred at the rate of hundreds per second. This transfer mode is spray transfer. The spray transfer mode can be further classified into drop spray and streaming spray, based on the droplet size. The diameter of the drop is equal or slightly larger than the welding wire in drop spray, while it is much smaller in streaming spray (Ref. 3). Both spray transfer modes are stable. However, in the streaming spray, small drops at a relatively high speed have a strong impact on the weld pool. The resultant weld formation is finger-shaped penetration, which is associated with poor mechanical properties (Ref. 4). The drop spray is generally characterized by uniform drop size, regular detachment, directional droplet transfer, and insignificant spatter, so it is a preferred

KEYWORDS Gas Metal Arc Welding Metal Transfer Ultrasonic Wave Ultrasonic Radiation Force

process (Ref. 5). However, the current range for drop spray transfer is relatively narrow — less than 10 A (Ref. 6). Small variables of the welding condition can bring a normal current variation larger than the narrow current range, so it is hard to maintain the drop spray process. On the other hand, globular transfer is associated with instable arc, spatter, and unacceptable weld appearance. This is mainly brought by the large drop size and low transfer frequency. Suppose that an auxiliary force can be applied on the droplet, the drop size will be minimized and the metal transfer frequency will be increased. As a result, the globular transfer will be a more stable and continuous process, similar to the drop spray process. In an effort to solve the above problem, application of an auxiliary force on the droplet has been achieved in a number of ways. The pulsed GMAW method uses pulsed current. A peak current higher than the transition current is used to produce a powerful electromagnetic force to detach the droplet (Refs. 7–9). The peak current value and duration time can be modulated to control the electromagnetic force. The average current for spray transfer decreases, but the transition current is unchanged. A reliable feedback signal is necessary to control the peak current and duration time because of the narrow range of transition current (Refs. 10–12). By monitoring excited droplet oscillation, the downward momentum of the droplet has been employed to enhance droplet detachment in the pulsed GMAW process. The peak current can be lower than the transition current, and accidental detachment is prevented (Ref. 13). Then the oscillation process of the droplet is improved by modified current waveforms. The metal transfer rate is further improved, and the control system is simplified (Ref. 14). The double-electrode GMAW (DE-GMAW) process adds a gas tungsten arc welding (GTAW) torch to the GMAW system, and the bypass arc produces an extra electromagnetic force to detach the droplet (Ref. 15). Then the DE-GMAW has been further modified into dual-bypass GMAW by adding two bypass tungsten electrodes (Ref. 16). As a result, two extra electroWELDING JOURNAL 91-s

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BY Y. Y. FAN, C. L. YANG, S. B. LIN, C. L. FAN, AND W. G. LIU

Fig. 1 — Acoustic radiation force distribution.

Fig. 2 — Water drops without ultrasonic wave (left) and with ultrasonic wave (right).

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Fig .3 — Schematic of U-GMAW.

magnetic forces are produced. Recently, a new process has been developed at the University of Kentucky by adding a laser beam to the droplet (Ref. 17). The laser recoil pressure produces an auxiliary force to detach the droplet. The metal transfer mode changes from short circuiting to spray after the laser is applied. It provides a new way to decouple the detaching force from the current. Question: Can another kind of force

with little relation to the current and heat be found as a supplement to the detaching force? On the other hand, the ultrasonic wave is a kind of mechanical vibration with a frequency equal or above 20 kHz. It has the advantages of excellent directivity and highenergy density, leading to several interesting ultrasonic effects. One of the effects is ultrasonic radiation force. It is the result of acoustic radiation pressure acting on the obstacle in an acoustic field. The ultrasonic wave has been introduced into the arc welding process. When the ultrasonic wave was directly applied onto the workpiece, it proved to be effective in grain refinement (Refs. 18, 19). When it was applied on the welding arc in gas tungsten arc welding, arc constriction was observed and the weld penetration depth increased (Ref. 20). For now, applications of the ultrasonic wave in the welding process are mainly devoted to improve the weld quality, but the fact of arc constriction indicates that the ultrasonic wave can propagate and form an acoustic

radiation field in the arc welding environment. It satisfies the basic preconditions for the acoustic radiation force. In this paper, the authors propose the idea of applying the ultrasonic radiation force to detach the droplets. The ultrasonic wave is introduced into the GMAW process, which is referred to 25 ultrasonic wave assisted GMAW (U-GMAW). The objective of this study is to prove the concept and feasibility of the U-GMAW method. However, further optimization and research are necessary for the drop detachment control process and industrial applications.

Theoretical Foundation and Principle In a stationary acoustic field, the acoustic radiation force acting on a sphere can be expressed as (Ref. 21)

( ) sin (2 kz )

5 F = πρ A 2 kR 0 s 6

3

Where p0 is the density of medium, A is the velocity potential of the incident wave, k is the wave number, Rs is the radius of sphere, and z is the vertical distance between the sphere and the reflector. From Equation 1, it can be seen that the acoustic radiation force is a static field. The value and direction of the force are not changed over time, but they vary with the vertical distance from the sphere to the reflector in the acoustic field. The distri-

Table 1 — Experimental Parameters Experimental Number

Wire Feed Speed (m/min)

Welding Voltage in Conventional GMAW (V)

Welding Voltage in Ultrasonic-Assisted GMAW (V)

1 2 3 4 5 6 7 8

3 3.5 4 4.5 5 5.5 6 6.5

27 27 27 27 27 27 28 28

31 31 32 32 32 33 33 33

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(1)

A

B

C

D

E

F

G

H

Fig. 5 — Photographing method of the metal transfer process.

bution cycle is half-wavelength in the medium. The force distribution is shown in Fig. 1. It can be seen that half of the acoustic field is filled with downward force. The principle of the U-GMAW method is meant to use the downward force as a supplement to the metal detachment. To better understand this process, a preliminary experiment was taken to evaluate the effect of the force. The detachment of the water drops was similar to the metal transfer process. A water tube with a diameter of 1.5 mm was selected to conduct the simulation experiment. The end of the tube was placed in the area of the downward force, as the zone “A” shown in Fig. 1. The ultrasonic frequency was 20 kHz. The vibration amplitude of the ultrasonic radiator was 30 μm, and the distance between the radiator and the workpiece was 17 mm. The water drop transfer process was recorded by a CCD camera at 150 frames per second. The images of the water drop prior to the detachment are shown in Fig. 2. The left one is of the conventional process while the right one is with the application of ultrasonic wave. It can be seen that the size of the water drop is much smaller after the ultrasonic wave is applied. The drop trans-

Fig. 6 — Metal transfer in conventional GMAW in Experiment 3. The interval between each image is 32 ms.

fer cycle time was only 1⁄10 of the conventional process. Also, the shape of the water drop was apparently different. It was elon-

gated in the axial direction of the water tube, and a longer neck was observed between the water drop and the tube. The difWELDING JOURNAL 93-s

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Fig. 4 — Experimental setup.

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A

B

C

D

E

F

G

H

amplified by the ultrasonic horn. The ultrasonic wave radiates out from the ultrasonic radiator. With the reflection by the workpiece, an acoustic radiation field forms between the ultrasonic radiator and workpiece. Meanwhile, the welding wire is fed through the axial hole of the ultrasonic vibration system, and there is no ultrasonic vibration acting on the wire. The welding process is carried out in the acoustic field. In this way, the ultrasonic wave works on the welding arc and droplet.

Experimental Setup and Conditions Fig. 7 — Metal transfer in U-GMAW in Experiment 3. The interval between each image is 13 ms.

ferences of the water drop detachments could be explained by the ultrasonic radiation force. In the acoustic field, the ultrasonic radiation force acted on the surface of the water drop. The liquid drop started to deform, and it elongated in the direction of the radiation force. When the water drop grew in size with time, the gravity of the drop and the radiation force on the drop increased with the size of the drop. The water drop was detached when the sum of the gravity and radiation force exceeded the surface tension. The water drop transfer process is the same as the droplet transfer process to some degree. The preliminary experimental results were consistent with the principle of the proposed method, and it 94-s

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may help explain the phenomena in the welding process. It should be mentioned that the complicated arc welding environment would affect the mode of the acoustic field, as well as the distribution of acoustic radiation force, but the nature of the force should not be changed. The schematic of the U-GMAW is shown in Fig. 3. The system is made up of an ultrasonic power source, a welding power source, and a hybrid welding gun. The main body of the welding gun is based on the ultrasonic vibration system, which can be further divided into the ultrasonic transducer and ultrasonic horn. The ultrasonic transducer transforms electric energy into ultrasonic vibration, and then the vibration is

Experimental Setup

The experimental setup is shown in Fig. 4. The welding gun was fixed, and the workpiece moved at a constant speed. The angle between the axis of the welding gun and the workpiece was 90 deg. A laser backlighted shadowgraphic method (Ref. 22) was used to monitor the metal transfer process, as shown in Fig. 5. In this method, a laser beam of 808 nm wavelength was used to provide back light. The light blocked by the welding wire and droplet would not reach the camera when traveling through the welding space. A band-pass filter centered at 808 nm wavelength was installed in front of the camera so that most of the laser light would be transmitted and most of the arc light would be excluded. As a result, the shadow

B

C

D

E

F

G

H

of the welding wire and droplet could be imaged by the high-speed camera at a rate of 3000 frames per second. Ultrasonic Parameters

There were three main ultrasonic parameters in the experiment. The ultrasonic frequency and the vibration amplitude are mainly concerned with the state of the incident wave, while the distance between the radiator and the workpiece decides the mode of the acoustic field. The ultrasonic frequency and the maximum amplitude are determined by the ultrasonic equipment. In this study, the ultrasonic frequency was 20 kHz. The power of the ultrasonic equipment was 110 W, and the corresponding vibration amplitude was 30 μm. The distance between the radiator and the workpiece was 30 mm, which maintained a strong acoustic field on the one hand, and eliminated the undesirable impacts of the GMAW process, like high temperature and spatter, on the other hand. However, the efficiency of the ultrasonic wave is not a primary concern in the preliminary study and the use of a more advanced ultrasonic power source and larger vibration amplitude should not change the effectiveness of the experimental results. Welding Conditions

The welding parameters used as variables in this study were wire feed speed and welding voltage, as shown in Table 1. Since the droplet size and the droplet transfer frequency are mainly determined by the welding current, the wire feed speed was varied continuously with the U-GMAW and com-

Fig. 8 — Droplets under different wire feed speeds in conventional GMAW experiments(m/min). A — 3; B — 3.5; C — 4; D — 4.5; E — 5; F — 5.5; G — 6; H — 6.5(m/min).

parative conventional GMAW processes. The welding voltages in U-GMAW experiments were higher than those in conventional GMAW experiments. In the preliminary research, it was found that the arc length decreased after the ultrasonic wave was applied on (Ref. 23). So the welding voltages of U-GMAW were set higher to get arcs long enough to maintain stable globular transfer processes. A constant voltage (CV) power supply was used during experiments, and the welding process was performed under direct current electrode positive (DCEP) conditions. The welding wire was ER70S-6 of 1.2 mm diameter, and the workpiece was mild steel. Pure argon was used as shielding gas at a flow rate of 25 L/min. The contact tube to workpiece distance (CTWD) was 24 mm, and the distance between the nozzle and the workpiece was 11 mm. Experiments were performed as bead-on-plate at a welding speed of 300 mm/min.

Experimental Results and Analysis Metal Transfer Process

Comparative experiments have been performed using the parameters shown in Table 1. Figure 6 illustrates an image sequence of a complete metal transfer cycle in conventional GMAW under experimental condition No. 3, where the wire feed speed is 4 m/min. The first image shows the end of the last transfer cycle, at the moment prior to the droplet detachment, and the last image shows the droplet prior to detachment in current transfer cycle. The metal transfer process was obviously in globular transfer mode. As can be seen, all droplets during the transfer cycle were approximately spherical. The droplet size grew gradually, and the diameters of the droplets prior to detachment were about three times the diameter of the

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A

A

B

C

D

E

F

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G

H

Fig. 9 — Droplets under different wire feed speeds in U-GMAW experiments (m/min.) A — 3; B — 3.5; C — 4 ; D — 4.5 ; E — 5; F — 5.5; G — 6; H — 6.5m/min.

welding wire, as shown in Fig. 6A and H. As a result, the metal transfer cycle lasted a long time — 226 ms. The average metal transfer frequency of conventional GMAW in Experiment 3 was about 4 Hz. The average welding current and voltage were 150 A and 26.7 V. The welding current was much lower than the transition current, so the metal transfer process observed was consistent with the expected metal transfer mode. A metal transfer cycle for U-GMAW under experimental condition No. 3 is shown in Fig. 7. It should be mentioned that all the images of the welding process 96-s

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were recorded under the same photographing condition. A noticeable effect of the ultrasonic wave on the welding process was the change of arc. Although the welding voltage was higher, the arc length was obviously shorter than that of the conventional GMAW. The compressed arc was brighter and part of the arc shape could be recognized in Fig. 7, while the arc of conventional GMAW was not bright enough to be seen in Fig. 6. With the assistance of the arc, the relative position of the droplet and the workpiece could be recognized in Fig. 7. Although the arc and the workpiece could not be seen in the conventional

GMAW process, the spatial relationship between the droplet and the workpiece in Fig. 6 was the same as Fig. 7. The height of droplet in the conventional GMAW process could be measured by the distance between the droplet and the welding nozzle. Meanwhile, the metal transfer process was also different from that of the conventional GMAW. The most characteristic feature is the deformation of the droplet. At first, the droplet size was small, and the droplet shape was approximately spherical. When the droplet diameter exceeded the wire diameter, the droplet started to deform. It was elongated in the axial direction of the welding wire while the diameter of the droplet no longer increased, as shown as differences between Fig. 7D and E. The deforming process lasted to the end of the transfer cycle. The resultant droplet shape was approximately ellipsoidal, as demonstrated in Fig. 7H. The length of the droplet in the axial direction of the welding wire was about two times the diameter of the droplet. Also, the neck between the welding wire and the droplet was longer than that of the conventional GMAW, compared between Fig. 6H and Fig. 7H. Although the droplet size could not be measured directly due to deformation, the droplet size in U-GMAW was apparently smaller than that in conventional GMAW. Since the wire feed speeds were constant in both two processes, the decrease of the droplet size would result in a decrease of metal transfer time and an in-

crease of metal transfer frequency. In this experiment condition, the cycle time was reduced from 226 to 92 ms while the metal transfer frequency increased from about 4 to about 10 Hz. The average welding current and voltage were 154 A and 31.7 V. The welding current was slightly higher than that of conventional GMAW, but such little difference was insufficient to cause a difference in the metal transfer process. The above metal transfer processes have shown that the U-GMAW method is consistent with the proposed principle to some degree. Although metal transfer was still in the globular transfer mode, the details of the process were improved and a more continuous droplet transfer process was achieved. A series of comparative results under different wire feed speeds were the result of the experimental conditions shown in Table. 1. The shapes of droplets prior to detachment in conventional GMAW and U-GMAW experiments are shown in Figs. 8 and 9, respectively. As can be seen, the droplet size decreased as the wire feed speed grew, because of the increasing welding current. This was observed in both conventional GMAW and U-GMAW. However, the differences are obvious. In the conventional GMAW process, all droplets were approximately spherical. In the U-GMAW process, droplets with deformation were always observed. All droplets were elongated in the axial direction of the welding wire and detached as ellipsoids. Also, the droplet sizes were apparently smaller than those of conventional GMAW under the same wire feed speed. At the wire feed speed of 6.5 m/min, the metal transfer mode changed into streaming spray transfer while the conventional GMAW process was still in globular transfer mode, as shown in Figs. 8H and 9H. Further experiment of the

Fig. 11 — Forces acting on the droplet.

conventional GMAW process was conducted, and streaming transfer mode was achieved at a higher wire feed speed of 7 m/min. No transition phenomenon was observed. It also proved that the transition current range was too narrow to get a stable drop spray transfer process when shielding with pure argon. The transition current in U-GMAW process was about 210 A, while it was about 220 A in conventional Fig. 12 — Comparison of predicted and measured droplet gravity. GMAW process. The metal transfer frequencies during the experimental processes were meascreased from 14 to 52 Hz at the wire feed ured, and average frequencies for each speed of 6 m/min. Such a high-frequency welding condition were calculated. Figure metal transfer process was similar to the 10 shows the differences for metal transdrop spray transfer mode. Even at a fer frequency between conventional lower wire feed speed of 5 m/min, the UGMAW and U-GMAW. It should be GMAW method could have a metal mentioned that the conditions of streamtransfer frequency above 20 Hz, which ing spray transfer mode were not concan maintain a relatively stable and contained in Fig. 10, since its metal transfer tinuous welding process. frequency was too high (above 200 Hz). It was proved that the U-GMAW If the range of the Y axis was enlarged by method could improve the metal transfer such a high frequency, it would be hard characteristics with a higher metal transto distinguish the details of the differfer frequency, in comparison with the ences of metal transfer frequency in globconventional GMAW. As a result, the ular transfer. It can be found that the welding process was more stable and conmetal transfer frequency increased with tinuous, which was consistent with the exthe wire feed speed in both processes. pected result of the proposed idea. The However, the increasing trend of Upreliminary explanation for changes in GMAW was faster than that of convenmetal transfer frequency could be attribtional GMAW. At the wire feed speed of uted to the changes in droplet sizes, but 3 m/min, the metal transfer frequency another question was raised: What had changed from 2 to 3 Hz, while it inled to the differences in droplet sizes? WELDING JOURNAL 97-s

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Fig. 10 — Metal transfer frequency.

is the surface tension coefficient. The balance of static forces is given by

Analysis of Ultrasonic Effect

The metal transfer process is the result of forces acting on the droplet. A droplet detaches when the total detaching forces exceed the total retaining forces. There are two complementary theories for studying the metal transfer mechanism (Refs. 24, 25). One is the static force balance theory; the other is the pinch instability theory. The former is appropriate for globular transfer mode at relatively low currents, while the latter is more suitable for spray transfer mode at high currents. In this paper, the static force balance theory was chosen to explain the differences in droplet size. In conventional GMAW, four different forces are usually considered: gravity force, electromagnetic force, and plasma drag force are detaching forces, while surface tension force is a retaining force. The gravity force can be expressed as

WELDING RESEARCH

4 F = π R 3ρ g g d d 3

(2)

Where Rd is the droplet radius, ρd is the density of the droplet, and g is the gravitational constant. The electromagnetic force can be expressed as

F

em

=

μ I2 0

4π R sinθ

⎡ ⎤ 1 1 ⎥ ⎢1n d − − ⎢ r 4 1 − cosθ ⎥ ⎢ ⎥ 2 2 ⎢+ ⎥ 1n ⎢ 2 1+ cosθ ⎥ ⎢⎣ 1 − cosθ ⎦⎥

(

)

(3)

Where μθ is the magnetic permittivity, I is the welding current, r is the welding wire radius, and θ is the half-angle subtended by the arc root at the center of the droplet. The plasma drag force can be expressed as

⎛ 2 ⎜ρf ν f F =C A ⎜ d D p ⎜ 2 ⎝

⎞ ⎟ ⎟ ⎟ ⎠

(4)

Where CD is the drag coefficient, Ap is the projected area on the plane perpendicular to the fluid flow, ρf is the fluid density, νf is the velocity of the gas. The surface tension force acting as retaining force is given as (5) Fs = 2πrσ Where r is the welding wire radius, and σ

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Fg + Fem + Fd = Fs

(6)

The droplet would not be detached until the detaching forces exceed the retaining force. From Equations 2–6, the gravity force can be calculated, and the droplet size can be predicted. Figure 11 shows the resulting forces required to detach the droplet. As can be seen, the surface tension force (Fs) and the plasma drag force (Fp) are almost constant. As the welding current increases, the electromagnetic force increases. The gravity force decreases as a result. In order to tell the differences between the conventional GMAW and U-GMAW, the experimental results of droplet gravity were compared with the predicted gravity force, given in Fig. 12. In conventional GMAW, the droplet sizes can be directly measured in images of metal transfer process and then the droplet gravity forces can be calculated. However, the droplets in U-GMAW were deformed and could not be measured directly. The equivalent droplet size was calculated by dividing the melting rate of the electrode by the average metal transfer frequency, and then the equivalent gravity force was calculated using Equation 2. As seen in Fig. 12, the theoretical results agree well with the experimental results obtained in the conventional GMAW process. It proves that the static force balance theory is suitable for globular transfer mode. For the U-GMAW process, there were great differences between the experimental results and the predicted results. Because the application of the ultrasonic wave could not change the variables in the equations of forces, it could be concluded that an additional force was brought in the metal transfer process by the ultrasonic wave. Furthermore, the difference in gravity forces between two processes can be considered as the value of the additional force, as shown in Fig. 12. In this case, the additional force was on the order of 10–3 N, which can provide a force about 1⁄5 of the surface tension force with a welding wire diameter of 1.2 mm. The nature of the additional force was further discussed. On the one hand, the water drop transfer process provided evidence. The water drop was elongated in the axial direction of the water tube, and the water drop size was decreased in the acoustic radiation force field. Similar phenomena were observed in the metal transfer process. On the other hand, the changing tendency of the additional force shown in Fig. 12 is consistent with the theoretical result of the acoustic radiation force. As the welding current increased, the droplet size decreased, which meant that the surface area being acted on by the

acoustic pressure was decreased. As shown in Equation 1, the decreased radius of sphere (Rs) would result in a decrease of the value of the acoustic radiation force. Hence, it can be concluded that the nature of the additional force should be acoustic radiation force. This result was in accord with the idea of the proposed method. The ultrasonic radiation force could be used as a supplement to the detaching force in metal transfer process.

Conclusions and Future Work 1) An experimental system has been established and the feasibility of the UGMAW method was experimentally demonstrated. 2) Deformation of the droplet was observed during the metal transfer process. The droplet was elongated in the axial direction of the welding wire, and the droplet size was decreased in comparison with the conventional GMAW. 3) The metal transfer frequency was increased compared with the conventional GMAW process. At a wire feed speed of 6 m/min, the U-GMAW process could maintain a metal transfer frequency of 52 Hz, while it was 14 Hz in the conventional GMAW process. 4) The ultrasonic radiation force was brought into the metal transfer process as a supplement to the detaching force. The value of the force was on the order of 10–3 N. The experimental results were consistent with the principle of the proposed method. However, the decrease in the transition current in U-GMAW was less than the other control methods such as active oscillation and laser enhanced GMAW. Also, there are some theoretical questions that need further research, such as the changes of acoustic field in the complicated welding environment, and so on. In the future work, the effect of the ultrasonic parameters on the characteristics of globular transfer will be evaluated, and the ultrasonic effect on the weld quality will be studied, especially on the microstructure and weld grain size. The ultimate goal of this method is to control the metal transfer process by applying pulsed ultrasonic wave to conventional GMAW or applying constant ultrasonic wave to pulsed GMAW. References 1. O’Brien, R. L., ed. 1991. Welding Handbook. 8th ed., Vol. 2: American Welding Society, Miami, Fla. 2. Lancaster, J. F. 1984. The Physics of Welding. Pergamon Press, Oxford, U.K. 3. Iordachescu, D., and Quintino, L. 2008. Steps toward a new classification of metal transfer in gas metal arc welding. Journal of Materials Processing Technology 202(1–3): 391–397.

12. Johnson, J. A., Carlson, N. M., Smartt, H. B., and Clark, D. E. 1991. Process control of GMAW: sensing of metal transfer mode. Welding Journal 70(4): 91-s to 99-s. 13. Zhang, Y. M., Liguo., E, and Kovacevic, R. 1998. Active metal transfer control by monitoring excited droplet oscillation. Welding Journal 77(9): 388-s to 395-s. 14. Zhang, Y. M., and Li, P. J. 2001. Modified active control of metal transfer and pulsed GMAW of titanium. Welding Journal 80(2): 54s to 61-s. 15. Li, K. H., Chen, J. S., and Zhang, Y. M. 2007. Double-electrode GMAW process and control. Welding Journal 86(8): 231-s to 237-s. 16. Shi, Y., Liu, X., Zhang, Y., and Johnson, M. 2008. Analysis of metal transfer and correlated influences in dual-pass GMAW of aluminum. Welding Journal 87(9): 229-s to 236-s. 17. Huang, Y., and Zhang, Y. M. 2010. Laser-enhanced GMAW. Welding Journal 89(9): 181-s to 188-s. 18. Cui, Y., Xu, C. L., and Han, Q. 2006. Effect of ultrasonic vibration on unmixed zone formation. Scripta Materialia 55(11): 975–978. 19. Dai, W. L. 2003. Effects of high-intensity ultrasonic-wave emission on the weldability of

aluminum alloy 7075-T6. Materials Letters 57: 2447–2454. 20. Sun, Q. J., Lin, S. B., Yang, C. L., and Zhao, G. Q. 2009. Penetration increase of AISI 304 using ultrasonic assisted tungsten inert gas welding. Science and Technology of Welding and Joining 14(8): 765–767. 21. King, L. V. 1934. On the acoustic radiation pressure on spheres. Proceedings of the Royal Society of London. Series A, Mathematical and Physical 147(11): 212–240. 22. Allemand, C. D., Schoeder, R., Ries, D. E., and Eager, T. W. 1985. A method of filming metal transfer in welding arcs. Welding Journal 64(1): 45–47. 23. Fan, Y. Y., Fan, C. L., Yang, C. L., Liu, W. G., and Lin, S. B. 2010. Development and preliminary study on the ultrasonic assisted GMAW method. China Welding 19(4): 1–5. 24. Kim, Y. S., and Eager, T. W. 1993. Analysis of metal transfer process in gas metal arc welding. Welding Journal 72(6): 269-s to 278-s. 25. Rhee, S., and Kannatey-Asibu, E. 1991. Analysis of arc pressure effect on metal transfer in gas-metal arc welding. Journal of Applied Physics 70(9): 5068–5075.

CAN WE TALK? The Welding Journal staff encourages an exchange of ideas with you, our readers. If you’d like to ask a question, share an idea or voice an opinion, you can call, write, e-mail or fax. Staff e-mail addresses are listed below, along with a guide to help you interact with the right person. Publisher Andrew Cullison [email protected], Extension 249 Article Submissions

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4. Essers, W. G., and Walter, R. 1981. Heat transfer and penetration mechanisms with GMA and plasma-GMA welding. Welding Journal 60(2): 37-s to 42-s. 5. Ueguri, S., Hara, K., and Komura, H. 1985. Study of metal transfer in pulsed GMA welding. Welding Journal 64(8): 242-s to 250-s. 6. Lesnewich, A. 1958. Control of melting rate and metal transfer. Welding Journal 37(9): 418-s to 425-s. 7. Essers, W. G., and Van Gompel, M. R. M. 1984. Arc control with pulsed GMA welding. Welding Journal 63(6): 26-s to 32-s. 8. Kim, Y. S., and Eager, T. W. 1993. Metal transfer in pulsed current gas metal arc welding. Welding Journal 72(7): 279-s to 287-s. 9. Allum, C. J. 1985. Welding technology data: pulsed MIG welding. Welding and Metal Fabrication 53(1): 24–30. 10. Wang, Q. L., and Li, P. J. 1997. Arc light sensing of droplet transfer and its analysis in pulsed GMAW process. Welding Journal 76(11): 458-s to 469-s. 11. Adam, G., and Siewert, T. A. 1990. Sensing of GMAW droplet transfer modes using ER 100s-1 electrode. Welding Journal 69(3): 103-s to 108-s.

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