Method Statement P91

FABRICATION OF CONVECTION SECTION ETHYLENE CRACKING FURNACES, RUWAIS 2 PROJECT

BOROUGE ABU DHABI POLYMERS COMPANY Ruwais U.A.E.

SELAS FLUID PROCESSING CORPORATION SFPC Contract # 07F-5122

FABRICATION OF CONVECTION SECTION FOE BOROUGE FURNACES

TITLE:

METHOD STATEMENT FOR SA 335 Gr. P91

SUB-CONTRACT: DESCON ENGINEERING P.O.BOX 46821, Abu Dhabi, U.A.E

Tel.(971 2)5555807, Fax.(971 2)5555784

0 REV.

DATE

ISSUED FOR APPROVAL

IZHAR

MAK

DESCRIPTION

PREP’D BY

APPROVED

SELAS-LINDE BOROUGE APPROVAL APPROVAL

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91

TABLE OF CONTENTS 1.

Scope

2.

Reference documents

3.

Material receiving and control

4.

WPS, PQR & WQT

5.

Training

6.

Material traceability

7.

Tack welding

8.

Preheating

9.

Welding

10. Post heating 11.

NDE before & after PWHT

12.

PWHT

13.

Welding Consumable Control

14.

Welding Repairs

15.

Preparation for Shipment

16.

Final inspection

17.

Attachments

Page 2 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91 1. Scope The document defines the implementation of QA/QC activities throughout the fabrication of convection section (pressure parts) only for SA 335 Gr. P91 material. 2. Reference documents •

ASME section I

•

ASME Boiler & Pressure vessel code section IX

•

1234-SPEC-F-ME-730 – Fabrication & Assembly Of Convection Modules

•

STND-SPEC-F-ME-733 – Fabrication of ASME BPVC section I Systems

•

STND-SPEC-A-ME-4004 - Low Chloride Marking Inks

•

BGS-MW-001 – Design General Specification Welding, NDE & preservation of brittle fracture of Pressure vessel & Heat Exchangers

•

BGS-LU-012 – Traceability Of Shop& Field Fabricated Piping Materials

•

BGS-LU-002 – Fabrication, Handling And Installation Of Process & Utility Piping

•

BGS-ME-002 - Shell And Tube Heat Exchanger

•

BGS-MU-012 - Requirements For Manufacturing Data Report For Non Pressure Vessel Equipments

•

BGS-MU-014 – Minimum Shop Inspection And Certification Required

•

BGS-MW-006 - Positive Material Identification Of Equipment & Piping

•

BGS-MX-003 –Design General Specification Internal Cleaning Of Piping

•

AUH/MANF/SOP-07 - Fabrication and material handling procedure

•

QC/M/3/1/01 - RT procedure

•

QC/M/3/05/01 - PWHT procedure

•

DES/SEL/QCP/002 - PMI procedure

•

QC/M/3/18/01 - Hardness testing procedure

•

QC/M/3/3/01 – Magnetic Particle Examination

•

QC/M/27/01 - Welding Consumable Control Procedure Page 3 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91

3. Material Receiving and Control •

Material receiving inspection shall be done in compliance with BOROUGE General Specifications (BGS-LU-012 – Traceability Of Shop & Field Fabricated Piping Materials) and (BGS-LU-002 – Fabrication, Handling And Installation Of Process & Utility Piping) STND-SPEC-A-ME-004 Low Chloride Marking Inks and approved procedure for fabrication (AUH/MANF/SOP-07).

•

Material as per specification & requirements with complete documents

•

Material conformity

•

Review of all documentation (delivery order, MTC etc)

•

Quantity check

•

Transport damages

•

Dimensional control

•

Marking on material

•

Storage of material separate from other materials on wooden blocks in marked area

•

When any defects like crack, dent etc. notice during visual inspection the same shall be confirmed by liquid penetrant inspection

4. WPS, PQR, WQT & WELD MAP •

Welding procedure specification (WPS), Procedure Qualification Record (PQR) and Welders Qualification Test shall be performed as per ASME IX and BOROUGE General Specifications BGS-MW-001 - Welding, NDE & preservation of brittle fracture of Pressure vessel & Heat Exchangers

•

Approval of WPS, PQR, WQT and WELD MAP will be as per approved ITP hold points.

Page 4 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91 5. Training •

Special induction course for P91 material shall be conducted for every involved fitter, fabricator and welder containing the all information about handling the P91, welding consumables, pre-heating, post heating, PWHT, machine setting, current voltages parameters, travel speed and to regulate purging gas system.

•

Complete job knowledge (Attachment # 1 Training for P91)

6. Material traceability •

Material traceability shall be done in compliance with BOROUGE General Specifications (BGS-LU-012 – Traceability Of Shop & Field Fabricated Piping Materials) and (BGS-LU-002 – Fabrication, Handling And Installation Of Process & Utility Piping) STND-SPEC-A-ME-004 Low Chloride Marking Inks and approved procedure for fabrication (AUH/MANF/SOP-07).

•

Cutting the material with grinders and transfer of heat number as per original length.

•

Each time when a marking is applied or shifted, the QC inspector shall verify the marking to ensure that the identification exists

•

Thermal cutting is not allowed on this material.

•

The weld bevels shall be carried out as per WPS and fit up shall be done properly to ensure proper alignment and root gap.

7. Weld Joint Preparation & Tack welding •

Weld Joint Preparation & Tack welding will be carried out according to (BGSMW-002 - Welding, NDE, & Preservation Of Brittle Fracture Of Piping)

•

Surfaces to be welded shall be clean and free from paint, oil, dirt, scale, oxides and other foreign material detrimental to the integrity of the weld.

•

Qualified welders will carry out tack welds.

Page 5 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91 8. Pre-heating •

Prior to start of welding, the joint will be pre-heated according to (BGS-MW-002 - Welding, NDE, & Preservation Of Brittle Fracture Of Piping)

•

Prior to start of pre-heating ensure that surface are clean and free from grease, oil and dirt.

•

Pre-heating shall be done by induction heating method.

•

Pre-heating temperature shall be made Min. 200 0C according to ASME Process piping B31.3

•

Pre-heating temperature shall be maintained and strictly controlled during welding.

•

Purging gas system shall be installed prior to start of pre-heating.

9. Welding •

Welding will be as per (BGS-MW-002 - Welding, NDE, & Preservation Of Brittle Fracture Of Piping)

•

Filling material shall be used as per approved WPS.

•

Root and hot pass welding shall be done using GTAW (as per WPS)

•

Argon gas of 99.99% shall be used for purging during the GTAW

•

Purging will start from inside off pipe when root temperature reaches the Min. pre-heating temperature 177 0C according ASME Process piping B31.3

•

Continuous and adequate argon gas flow rate (as per WPS) to ensure complete purging in the root area

•

Visual inspection shall be carried out on root weld maintaining pre-heating temperature.

•

After GTAW minimum one pass of SMAW shall be continue. Filling and capping shall be done using SMAW

•

Intermediate pass temperature shall be Max. 300 0C.

Page 6 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91 •

Portable flasks or oven shall be used by the welders for carrying electrodes to the place to use

•

SMAW electrodes used must be dried in drying ovens with calibrated temperature control.

•

Daily welding report shall be recorded on the approved daily welding report format.

•

Complete welded joints shall be marked with the welders identification stamp and recorded in the daily welding report (See attachment # 2-AUH/QA&QC/FRM-78)

10. Intermediate PWHT •

After welding Intermediate PWHT shall be done according to (BGS-MW-002 Welding, NDE, & Preservation Of Brittle Fracture Of Piping)

•

Intermediate PWHT shall be done only for material having thickness >10mm.

•

For post heating detail see post-heating table – 3 on page # 11.

11. NDE Before & After PWHT •

Radiographic examination 100% before stress relief (BSR) and after stress relief (ASR) for all Butt-welded joints shall be carried out according to the approved RT procedure (1234-PROD-F-VD-228).

•

After completion of PWHT, 100% positive material identification (PMI) shall be done as per(BGS-MW-006 - Positive Material Identification Of Equipment & Piping) on the weld metal & base metals as per approved procedure (1234-PROCF-VD-224) and reading was noted in the approved format.

•

100% Hardness testing after PWHT shall be done in compliance with approved Hardness procedure (1234-PROD-F-VD-227).

•

The maximum value for hardness will be 290 HB.

•

Magnetic Particle examination after PWHT shall be done as per approved procedure (1234-PROD-F-VD-280). Page 7 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91

Note It is noticed that hold point for the above mentioned NDE activities should be as per approved inspection and testing plan (ITP), As reference documents (DES-SL-MITP-OO4 Rev 00& DES-SL-M-ITP-005 Rev 00). 12. Post Weld Heat Treatment (PWHT) •

PWHT shall be done in compliance with approved PWHT procedure (QC/M/3/05/01) and (BGS-MW-002 - Welding, NDE, & Preservation Of Brittle Fracture Of Piping)

•

The heating and cooling rate for this material is 1500C +/- 100C per hour

•

2 hours holding time at 720 0C ~ 760 0C

•

PWHT temperature shall always be minimum 30 0C below the tempering temperature of the material.

•

Below 300 0C cooling shall be done with insulation.

•

No interruption is allowed during PWHT.

•

Do not allow moisture, rain, water, cold wind, cold draft etc. to come in contact with the weld zone or heating zone during the entire cycle from preheat to PWHT.

•

Do not exceed the limits of PWHT soaking temperature.

13. Welding Consumable Control • Welding Consumable Control as per approved procedure (QC/M/27/01). 14. Welding Repairs • Welding repair shall be done as per approved procedure (QC/M/3/26/01). 15. Preparation for Shipment • Preparation for shipment shall be done as per (1234-SPEC-F-ME-730).

Page 8 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91 HEAT & COOLING CHART FOR <10 mm

TABLE -1

S. No.

Operation

Temp. Min. 200 0C

1

Preheating

2

Welding by GTAW + SMAW

Interpass Max. 300 0C

3

Cooling

150 0C +/- 100C / hour

RT Before PWHT

NDE 4

Heating for PWHT

5

Holding on PWHT

Reach 750 C @ 150 0C / hour 2h at 750 0C

6

Cooling

150 0C / hour

0

Page 9 of 11

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91 HEAT & COOLING CHART FOR >10 mm

TABLE - 2

S. No.

Operation

1 2 3 4 NDE

Preheating Welding by GTAW + SMAW Post Heating Cooling RT Before PWHT

5

Heating for PWHT

6 7

Holding on PWHT Cooling

Page 10 of 11

Temp.

Min. 200 0C Interpass Max. 300 0C See table below 150 0C +/- 100C / hour 0 Reach 750 C @ 150 0C / hour 2h at 750 0C 0 150 C / hour

DESCON ENGINEERING. METHOD STATEMENT FOR SA 335 Gr.P91 Post Heating Table - 3 (Holding time in Hours) Holding temperature

Thickness (mm) 10~20 20~30

150 0C 1.5 6

200 0C 1 3

250 0C 1 2

300 0C 0.5 1.5

Note •

Below 300 0C cooling on ambient air with insulation

•

PWHT temperature shall always be minimum 30 0C below the tempering temperature of the material.

16. Final inspection •

In the end of completing a spool, Visual and complete dimensional inspection will be carried out according to the project specification.

•

Complete dimension of spools shall be verified as per drawing ad within the tolerance of the project specification.

•

Final check of all QC activities on all the welded joints of complete spool.

•

Final release for pressure testing as per applicable code and Procedure.

17. Attachments •

Attachment # 1 – Training Complete job knowledge

•

Attachment # 2 – Daily welding inspection report

•

Attachment # 3 – Stepwise complete fabrication chart

•

Attachment # 4 – Weld heating sketch during welding

Page 11 of 11

DESCON ENGINEERING.

Complete Job Knowledge (SA 335 Gr.P91)

Attachment # 1 Training for Complete Job Knowledge (SA 335 Gr.P91) The personnel engaged in P91 piping fabrication shall be trained in the following areas a. How to identify the P91 material b. Method and cares during cutting and joint preparation. c. Tack welding and set up prior to start of welding d. Cleanliness of the fusion face e. Strict implementation of relevant WPS f. Arrangements for pre-post heating requirements and methods g. Special cares and precaution to control preheat temperature h. Argon gas root purging arrangement. i. Heating cycle condition. j. How to identify welding consumables k. Use of filler material as per WPS l. Handling of P91 welding consumables and re-drying conditions m. Setting/installation of welding machine n. Current and voltages parameters setting as per WPS o. Travel speed and heating temperature control as per WPS p. How to identify the gases (shielding gas, purging gas) q. How to install purging gas system r. Maintain gas flow rate as per WPS s. Fixing of thermocouple and wires. t. Adjustment of heating pads / cables at the time of controlling the temperature within specified tolerance limits during PWHT in case of induction heating. u. Good appreciation of the WPS requirements. v. Special precautions during the power / equipment failure. w. Weld defect control and weld repair system. x. Welding techniques and instructions on Do’s and Do Nots of P91 welding. Page 1 of 4

DESCON ENGINEERING.

Complete Job Knowledge (SA 335 Gr.P91) y. Welders only who are qualified on P91 welding alone shall be engaged. Whenever new welders have to be engaged they shall undergo all the training as above and shall be qualified with P91 material only.

Personnel / Contractors engaged for heating cycles (HT Operator) The Personnel / Contractor shall have adequate heat treat experience on P91 or similar material. HT operator shall be aware of the following: a. The equipment used and its working principle and operation. b. The procedures to be followed in using heating equipments. c. Procedure to be followed in case of power failure or equipment on functioning so that heating cycle is not disrupted. d. Calibration of equipments. e. Method of fixing thermocouples and compensating cables leading to HT recorder. f. Fixing of heating pads or elements on the pipe joints and also in maintaining within the specified limits.

Page 2 of 4

DESCON ENGINEERING.

Complete Job Knowledge (SA 335 Gr.P91)

DO's and DON’Ts during P91 welding, heat treatment and NDE DO's a. Pipes Edge Preparation with care as per WPS b. Grinding may be done on exceptional cases after approval and taking adequate care to prevent overheating. c. Ensure adequate Argon Gas for complete purging of air inside the pipe before starting GTAW root welding. d. Ensure Preheating at 200 0C minimum before GTAW root welding e. Start preheating only after clearance from Welding Inspector for weld fit-up and alignment of the joint f. Do visual inspection on root weld maintaining weld preheating temp. g. Continue Argon purging until the GTAW root welding h. Perform partial root welding to facilitate fit-up if necessary. i. Ensure proper use of TIG wires as identified by colour coding or suitable hard punching j. Keep the GTAW wires in absolutely clean condition and free from oil, rust, etc. k. Dry the SMAW electrodes before use. l. Ensure the interpass temperature is maximum 300 0C m. Record entire heating cycle on Chart through recorders. n. Exercise control during grinding of weld and adjoining base metal while removing surface / sub-surface defects or during preparation for NDE. o. Ensure no contract with moisture during preheat, welding, post heat and PWHT of weld joints p. Ensure removal of argon purging arrangements after welding. q. Use short Arc only. The maximum weaving shall be limited to as per approved WPS

Page 3 of 4

DESCON ENGINEERING.

Complete Job Knowledge (SA 335 Gr.P91) DONTs a. Avoid Oxy-Acetylene flame or any thermal cutting cutting. b. Avoid Are strike on materials at the time of weld fit up or during welding. c. Do not Tack weld the thermocouple wires with Manual Are/TIG welding d. NO GTAW root welding without thorough purging of root area. e. Do not use Oxy-acetylene flame heating for any heating requirements. f. Do not use unidentified TIG wires or electrodes. g. Do not exceed the maximum interpass temperature indicated in WPS h. Do not allow moisture, rain, water, cold wind, cold draft etc. to come in contact with the weld zone or heating zone during the entire cycle from preheat to PWHT. i. Do not exceed the limits of PWHT soaking temperature. j. Do not Interrupt the Welding / heating cycle. k. Do not use uncalibrated equipment for temperature measurement during heating, welding, post weld, heat treating etc.,

Page 4 of 4

JOB KNOWLEDGE INDUCTION FOR SA 335 Gr. P91 ATTENDENCE SHEET S.No. EMP.No.

NAME

CRAFT

SIGNATURE

Doc.No.: AUH/QA&QC/FRM-78

DESCON ENGINEERING ABU DHABI

Rev. : 00 Date : Feb 15,06

DAILY WELDING INSPECTION REPORT

Page : 1 of 1

Report No. : Sr. No.

Supervisor Name:

ISO / Line No. / Drawings No.

Weld Type

Weld No.

Malik Kashif Welder

Dia

Thick

WPS No.

Malik Kashif

Root

Fill

Cap

Item # 1

Item # 2

DESCON QA/QC

PREPARED BY NAME :

Area

NAME :

Mumtaz Ahmed

Heat No. 2

Visual Inspection Fit-up

SELAS-LINDE NAME :

DATE :

DATE :

DATE :

SIGNATURE

SIGNATURE

SIGNATURE

DESCON Engineering

Heat No. 1

Welding

STEPWISE FABRICATION AND INSPECTION OF P91 &P11 FIT-UP

Fit-up

Pre-heating As Per Approved Method Statement (FIG ATTACHMENT# 1)

Welding

WELDING Post-Heating (Only for P91) As Per Approved Method Statement (FIG ATTACHMENT# 1)

RT (Before PWHT) As Per Approved Procedure (1234-PROC-F-VD-228R0)

Elbow to Tube weld without Bridge

PWHT As Per Approved Procedure (1234-WELD-F-VD-231R0)

A. Bridge Plate Welding

Tube to Tube weld with Bride

Pre-Heating for Bridge Plate Welding As Per Approved Method Statement

RT (After PWHT) As Per Approved Procedure (1234-PROC-F-VD-228R0)

Bridge Plate Welding

MT As Per Approved Procedure (1234-PROC-F-VD-280R0)

Post-Heating (Only for P91) As Per Approved Method Statement

PMI As Per Approved Procedure (1234-PROC-F-VD-224R0)

Hardness As Per Approved Procedure (1234-PROC-F-VD-227R0)

PWHT As Per Approved Procedure (1234-WELD-F-VD-231R0)

MT As Per Approved Procedure (1234-PROC-F-VD-280R0)

PMI(only Butt welds) As Per Approved Procedure (1234-PROC-F-VD-224R0)

Hardness(only Butt welds) As Per Approved Procedure (1234-PROC-F-VD-227R0)

B. Bridge Plate Welding

Side View of tube with Bridge Plates

ATTACHMENT # 4 PRE-HEATING & INTERMEDIATE POST HEATING FOR P91