specification for welding of duplex stainless steel pipelines amendmentssupplements to api std 1104

Petroleum Development Oman L.L.C.

UNRESTRICTED Document ID : SP-1097May 2005 Filing key :

Specification for Welding of Duplex Stainless Steel Pipelines

(Amendments/Supplements to API Std 1104)

Keywords:

API 1104Duplex Stainless SteelInspectionOff-plotPipelinesProcedure Qualification RecordProduction WeldingTestingWelding Procedure SpecificationWelder Qualification

This document is the property of Petroleum Development Oman, LLC. Neither the whole nor any part of this document may be disclosed to others or reproduced, stored in a retrieval system, or transmitted in any form by any means (electronic, mechanical, reprographic recording or otherwise) without prior written consent of the owner.

Specification for Welding of Duplex Stainless Steel Pipelines Version 2.0

Authorised For Issue

Signed :........................................................UER (UEC/1)CFDH Materials and Corrosion

The following is a brief summary of the 4 most recent revisions to this document. Details of all revisions prior to these are held on file by the issuing department.

Version No. Date Author Scope / RemarksVersion 1.0 3/8/99 OTT/112 Extensive revision of original issue of SP

1189.Version 2.0 25/05/05 UEC/11 Updated based on past experience

May 2005 SP-1097i

Version 2.0 Specification for Welding of Duplex Stainless Steel Pipelines

Contents

1. Introduction.................................................................................................................... 11.1 Purpose....................................................................................................................... 11.2 Changes to the Specification.......................................................................................1

2. Specification for Welding Duplex Stainless Steel..........................................................22.1 Specification Requirements.........................................................................................22.2 Process Deliverables...................................................................................................22.3 Process Owner's Responsibility...................................................................................22.4 Performance Levels / Indicators..................................................................................22.5 Performance Monitoring.............................................................................................32.6 Effective period..........................................................................................................32.7 Review and Improvement...........................................................................................3

Appendix A Glossary of Definitions, Terms and Abbreviations........................................4

Appendix B Amendments/Supplements to API Spec 1104................................................7

1 General........................................................................................................................... 71.1 Scope.......................................................................................................................... 7

2 Referenced Publications.................................................................................................7

3 Definition of Terms.........................................................................................................7

4 Specifications.................................................................................................................. 74.1 Equipment.................................................................................................................. 74.2 Materials..................................................................................................................... 8

4.2.1 Pipe and fittings..........................................................................................84.2.2 Filler metal.................................................................................................84.2.3 Shielding gases...........................................................................................9

4.3 Quality System.......................................................................................................... 10

5 Qualification of Welding Procedures for Welds Containing Filler Metal Additives. .115.1 Procedure Qualification.............................................................................................115.2 Record...................................................................................................................... 115.3 Procedure Specification.............................................................................................12

5.3.1 General.....................................................................................................125.3.2 Specification information..........................................................................12

5.2 Essential Variables....................................................................................................155.4.2 Changes requiring requalification..............................................................15

5.5 Welding of Test Joints - Butt Welds..........................................................................175.6 Testing Of Welded Joints - Butt Welds.....................................................................18

5.6.1 Preparation................................................................................................185.6.3 Nick-break test..........................................................................................185.6.6 Macroscopic examination and hardness test..............................................195.6.7 Ferrite measurement..................................................................................195.6.8 Charpy V-Notch Impact Testing................................................................205.6.9 Corrosion Testing......................................................................................205.6.10 Chemical analysis.....................................................................................215.6.11 Retests......................................................................................................21

5.7 Welding of Test Joints - Fillet Welds........................................................................225.8 Testing Of Welded Joints - Fillet Welds....................................................................22

5.8.1 Preparation................................................................................................225.8.2 Method......................................................................................................235.8.3 Requirements............................................................................................23

5.9 Welding of Test Repair Welds..................................................................................23

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5.10 Testing of Repair Welds.................................................................................235.10.1 Preparation................................................................................................235.10.2 Method......................................................................................................235.10.3 Requirements............................................................................................23

5.11 Records..........................................................................................................23

6 Qualification of Welders...............................................................................................246.1 General..................................................................................................................... 246.2 Single Qualification..................................................................................................24

6.2.1 General.....................................................................................................246.2.2 Scope........................................................................................................24

6.3 Multiple Qualification...............................................................................................256.3.1 General.....................................................................................................256.3.2 Scope........................................................................................................25

6.4 Visual Examination...................................................................................................256.5 Destructive Testing...................................................................................................25

6.5.1 Sampling of test butt welds.......................................................................256.5.2 Tensile strength, nick-break and bend test procedures for butt welds.........256.5.6 Sampling of test fillet welds......................................................................256.5.6 Sampling of Test Fillet Welds and Branch Welds......................................256.5.7 Test methods and requirements for fillet welds..........................................266.5.7 Test Methods and Requirements for Fillet Welds and Branch Welds.........26

6.6 Radiography - Butt Welds Only................................................................................266.6.1 General.....................................................................................................266.6.2 Inspection requirements............................................................................26

6.7 Retesting................................................................................................................... 266.8 Records..................................................................................................................... 26

7 Production Welding......................................................................................................277.1 General..................................................................................................................... 27

7.1.1 Handling and storage.................................................................................277.1.2 Weather protection....................................................................................28

7.2 Alignment................................................................................................................. 287.3 Use of Line-Up Clamp for Butt Welds......................................................................287.4 Bevel........................................................................................................................ 29

7.4.2 Field bevel................................................................................................297.7 Cleaning Between Beads...........................................................................................297.8 Position Welding.......................................................................................................29

7.8.2 Filler and finish beads...............................................................................297.10 Identification of Welds...................................................................................297.11 Pre- and Post-Heat Treatment.........................................................................30

7.11.1 Preheat and interpass temperature control and measurement......................307.11.2 Post-weld heat treatment...........................................................................30

7.12 Separation of Girth Welds..............................................................................307.13 Weld Interruption...........................................................................................307.15 Weld Finishing...............................................................................................307.16 Shielding and Backing Gas.............................................................................31

8 Inspection and Testing of Production Welds...............................................................318.2 Methods of Inspection...............................................................................................318.3 Qualification of Inspection Personnel........................................................................318.4 Certification of Non-Destructive Testing Personnel..................................................31

8.4.1 Procedures................................................................................................318.5 Extent of Inspection and Testing...............................................................................328.6 Records..................................................................................................................... 32

9 Acceptance Standards for Non-Destructive Testing....................................................329.1 General..................................................................................................................... 329.3 Radiographic Testing................................................................................................33

9.3.1 Inadequate Penetration..............................................................................33

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9.3.2 Inadequate penetration due to high-low.....................................................339.3.3 Incomplete Fusion.....................................................................................339.3.6 Burn-Through...........................................................................................339.3.8 Slag Inclusions..........................................................................................339.3.9 Cracks.......................................................................................................33

9.4 Magnetic Particle Testing..........................................................................................349.5 Liquid Penetrant Testing...........................................................................................34

9.5.2 Acceptance standards................................................................................349.6 Ultrasonic Testing.....................................................................................................34

9.6.2 Linear indications.....................................................................................34

10 Repair and Removal of Defects....................................................................................3410.1 Defects Other Than Cracks.............................................................................34

10.1.1 Authorisation for repair.............................................................................3410.1.2 Removal and preparation for repair...........................................................3510.1.3 Testing of Repairs.....................................................................................35

10.2 Authorisation and Procedure for Repair of Cracks..........................................35

11 Procedures for Non-Destructive Testing......................................................................3511.1 Radiographic Test Methods............................................................................35

11.1.1 General.....................................................................................................3511.1.3 Exposure geometry...................................................................................3611.1.4 Type of penetrameters...............................................................................3611.1.5 Selection of penetrameters........................................................................3611.1.6 Placement of penetrameters.......................................................................3611.1.9 Storage of film and other imaging media...................................................3611.1.10 Film density..............................................................................................3711.1.10 Film density and sensitivity.......................................................................3711.1.11 Image processing......................................................................................37

11.2 Magnetic Particle Test Method.......................................................................3711.4 Ultrasonic Test Method..................................................................................37

12 Automatic Welding.......................................................................................................37

13 Automatic Welding Without Filler-Metal Additions...................................................37

14 Documentation.............................................................................................................. 3814.1 General........................................................................................................... 3814.2 Certificate of Conformity...............................................................................38

Appendices to API 1104.....................................................................................................39

A Alternative Acceptance Standards for Girth Welds....................................................39A1 General..................................................................................................................... 39

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B In-Service Welding.......................................................................................................39

Figure A - Location of Macrosection and Impact Test Specimens...................................40

Figure B - Orientation and Location of Charpy Impact Specimens.................................41

Figure C - Hardness Indent Locations..............................................................................42

Appendix C References.....................................................................................................43

Appendix D Determination of the Volume Fraction of Ferrite in Duplex Stainless Steel by Systematic Point Count................................................................................................45

Appendix E Certificate of Compliance ………….………………………………………… 48

Error! Bookmark not defined.User Comment Form............................................................50

May 2005 SP-1097v


1. Introduction

1.1 Purpose

This specification is a revision of SP-1097 version 1.0, Specification for Welding of Duplex Stainless Steel Pipelines, issued in July 1999.. The purpose of this specification is to define the minimum technical requirements for the welding of duplex stainless steel pipelines and flowlines.

The basis of this specification is API Std 1104 nineteenth edition, September 1999 including Errata dated October 31 2001.

1.2 Changes to the Specification

This specification shall not be changed without approval from the Custodian, the Material & Corrosion Functional Discipline Head (CFDH), UER (UEC/1), who owns this specification. If you think the specification is not correct, write your comments on a copy of the User Comments Form. The form is included as the last page of this specification. Send the copy with your comments and personal details to DCS.

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2. Specification for Welding Duplex Stainless Steel

This Specification gives the minimum technical requirements for the welding of duplex stainless steel pipelines and ancillary equipment where the applicable Code has been defined by the Company as ASME B31.4 or ASME B31.8.

This Specification is applicable to all classes of pipelines as defined in SP-1211 and is based on API Std 1104, nineteenth edition, September 1999 including Errata dated October 31 2001. Appendix B gives amendments and supplements to the base standard. Tables or figures supplementary to those of API Std 1104 have been designated with capital letters.

This document is not applicable to:

Welding of on-plot pipework and fabricated equipment, (covered by PDO specification SP-1096)

Manufacture of longitudinally welded pipe, (covered by PDO specification SP 1189) Welding onto pipelines under operating conditions, (hot tap operations)

Welding of pipelines on use in sour service, as defined under NACE MR0175/ISO15156

2.1 Specification Requirements

Welding, fabrication and inspection shall be in accordance with the requirements of API Std 1104, nineteenth edition, September 1999 including Errata dated October 31 2001, as amended and supplemented by Appendix B of this specification.

The scope of API Std 1104 is confined to carbon and low alloy steels and the extensive amendments and supplements of the text in Appendix B have been necessary to incorporate the special requirements for welding duplex stainless steels. Other general amendments and supplements are included in Appendix B where considered necessary to ensure pipeline integrity in accordance with PDO and Shell Group requirements

The Clause numbering in Appendix B follows that of API Std 1104. Where clauses of API 1104 are not amended or supplemented they shall apply in their entirety.

2.2 Process Deliverables

Process deliverables comprise field welded duplex stainless steel pipelines, flowlines and related welded fabrications designed to ASME B31.4 or ASME B31.8 and intended for off-plot oil and gas service.

2.3 Process Owner's Responsibility

The owner of this specification, UER, as CFDH Materials and Corrosion, is responsible for authorising all proposed deviations or amendments to the specification and for the instigation of periodic reviews and updates in accordance with Clauses 1.2 and 2.7.

2.4 Performance Levels / Indicators

See relevant API Std 1104 weld inspection and testing acceptance criteria and the amendments/supplements given in Appendix B of this specification.

2.5 Performance Monitoring

Requirements for monitoring welding process variables, welder performance and weld quality are detailed in relevant sections of API Std 1104 as amended by Appendix B of this specification.

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2.6 Effective period

The requirements of this specification shall remain in force indefinitely unless superseded by an authorised revision.

2.7 Review and Improvement

This specification will be reviewed and updated once every three years. The review authority will be UER (UEC/1, CFDH Materials and Corrosion).

May 2005 Page 3 SP-1097


Appendix A Glossary of Definitions, Terms and Abbreviations

Certain terms and abbreviations used in this document are defined below. The listed definitions shall be considered to supplement those given in API Std 1104.

General Definitions

Contractor The party which carries out all or part of the design, engineering, procurement, construction, commissioning or management of a project, or operation or maintenance of a facility. The Company may undertake all or part of the duties of the Contractor.

Manufacturer/ Supplier

The party which manufactures or supplies equipment and services to perform the duties specified by the Contractor.

Company Petroleum Developmant Oman LLC. The Company will generally specify the technical requirements. The Company may also include an agent or consultant authorised to act for, and on behalf of, the Company.

User The Company, Consultant or Contractor who uses this document.

Corporate Functional Discipline Head

The person within the Company responsible for the discipline to which the standard belongs

shall Indicates a requirement. Any deviation to a requirement shall be approved by the CFDH.

should Indicates a recommendation. A deviation to a recommendation shall be approved by the Company welding-TA 2.

may Indicates a possible course of action.

Specific Definitions

Batch or Lot(see App. B, 4.2.2.1)

As defined in AWS A5.01, Clause 5 (Classification) and Clause 6 (Testing)

Duplex stainless steel A chromium-nickel-molybdenum stainless steel containing a balance of austenite and ferrite stabilising alloying elements such that the microstructure at room temperature consists of approximately equal proportions of austenite and ferrite.

Nominal thickness Nominal thickness t shall have the following meanings:

- butt joint; parent metal thickness, which for joints between dissimilar thicknesses is that of the thinner material.- fillet weld; parent metal thickness, which for joints between dissimilar thicknesses is that of the thicker material.- set-on branch connection; thickness of branch pipe- set-through branch connection; thickness of main pipe.

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Verified Copy A photocopy of an original document which has been re-endorsed and signed by the organisation producing the photocopy to verify that none of the information has been adulterated.

Welding Co-ordinator The Contractor nominated authority on the quality aspects of welding. The Welding Co-ordinator shall be a Welding Engineer meeting the recommendations for European Welding Engineer (refer ISO 14731). However, other national/international qualifications may be considered at the discretion of the Company. The Welding Co-ordinator shall be approved by the Company TA-2 (Welding).

Abbreviations

a Throat Thickness of Fillet Weld

AWS American Welding Society

CSWIP Certification Scheme for Welding Inspection Personnel

D Nominal Outside Diameter

FCAW Flux Cored Arc Welding

GMAW Gas Metal Arc Welding

GTAW Gas Tungsten Arc Welding

HAZ Heat Affected Zone

HV Vickers Hardness

NDE Non-destructive Examination

PAMS Portable arc monitoring system

PCN Personnel Certification in NDE

PQR Procedure Qualification Record

PRE Pitting Resistance Equivalent

PT Penetrant Testing

PWHT Post Weld Heat Treatment

RT Radiographic Testing

SAW Submerged Arc Welding

SMAW Shielded Metal Arc Welding

t Nominal Thickness

May 2005 Page 5 SP-1097


TA Technical Authority, as defined in ERD-00-02 and PDO GU-272.

UNS Unified Numbering System

WPS Welding Procedure Specification

SP-1097 Page 6 May 2005


Appendix B Amendments/Supplements to API Spec 1104

1 General

1.1 Scope

Replace existing section as follows:

This specification covers the arc welding of butt and fillet welds in duplex stainless steel for pipelines and related facilities.

Welding may be carried out by a SMAW, GTAW, GMAW, SAW, or gas shielded FCAW process, or a combination of these processes. A manual, semi-automatic, or automatic welding technique, or combination of these techniques, may be used. The first and second passes of single sided butt welds shall be made using the manual or automatic GTAW process. Filler metal shall be used for all passes. Roll welding shall be accepted by the Company only when an automatic welding process is used.

GMAW, GTAW, and gas shielded FCAW shall be restricted to construction areas protected against wind and draught.

This specification also covers the procedure requirements and acceptance standards for test and production welds destructively tested or inspected by radiography, ultrasonics, or liquid penetrant techniques.

2 Referenced Publications

See also Appendix C of this specification.

3 Definition of Terms

See also Appendix A of this specification.

4 Specifications

4.1 Equipment


Welding plant, instrumentation, tools, and accessories shall be suitably maintained in accordance with manufacturers' instructions and shall have adequate capacity for the welding procedures to be employed. GTAW power units shall incorporate a high frequency starting unit, slope-out control and gas delay facility as a minimum. Welding plant electrical output, portable voltmeters/ammeters, wire feed speed meters, and gas flow meters shall be calibrated immediately prior to welding, and thereafter at intervals defined in the Contractor's calibration procedure. A log of the calibration status shall be maintained.

Pipe handling equipment, rollers, and line-up clamps shall neither damage nor contaminate the pipes and shall achieve the specified fit-up. As far as is practicable, direct contact shall be prevented between duplex stainless steel and carbon steel equipment. Line-up clamps and supports shall have stainless steel inserts or shall be lined/overlaid with a compatible material. Spacing tools shall be of stainless steel. Nylon slings shall be used for lifting duplex stainless steel components.

During preparation for welding and cleaning or dressing of weld deposits and components, only grinding wheels dedicated to stainless steel work shall be used. Wire brushes shall be

May 2005 Page 7 SP-1097


of stainless steel. All such dedicated equipment and consumables shall be identified by colour coding or other suitable means.

4.2 Materials

4.2.1 Pipe and fittings


Pipe shall be in accordance with one of the following:

PDO SP 1189

Fittings shall be in accordance with one of the following:

PPS Specifications Shell/Company MESC codes

The Contractor shall obtain verified copies of the materials certificates for all free-issue items to be welded. Contractor supplied items shall have original or verified copies of materials certificates and certification. Items without materials certificates shall not be used unless they are re-certified through re-testing and material is positively identified by suitable marking on the pipe.

4.2.2 Filler metal

4.2.2.1 Type and size


Filler metals should be of matching specification to the base material to be welded with the exception of the following:

The chromium and nickel contents of each batch should be equal to or higher than those of the filler used in the corresponding procedure qualification test.

The PRE of the filler metal, as calculated from the batch test certification on the basis defined below, should be at least 2 units higher than the minimum specified for the base material to be welded.

PRE = (%Cr) + 3.3(%Mo + 0.5%W) + 16(%N)

NOTE: Tungsten (W) analysis need be considered only if specified as an alloying addition.

Each batch of consumables shall be tested in accordance with the AWS procedures specified for the consumable classification. For SDSS, batch testing shall be conducted with third party witness and verification at a Company-approved facility. The definition of a batch is given in Appendix A of this specification.

All filler metals shall have classification society, e.g. Lloyd's, DNV type approval. And shall be from a manufacturer acceptable to the Company Welding TA-2.

4.2.2.2 Storage and handling of filler metals and fluxes


Electrodes, filler wires, and fluxes shall be stored in a dry storage room in accordance with the manufacturers’ instructions. Consumables shall remain in their original containers, which shall be marked with the manufacturer’s name, the consumable trade name, and the

SP-1097 Page 8 May 2005


batch number. Consumables in containers that are not identifiable and traceable shall be removed from the job site to the satisfaction of the Company. The storage room shall have a maximum relative humidity of 50%, which shall be monitored in accordance with an agreed procedure.

Consumables that show signs of damage or deterioration, e.g., cracked or flaked coatings, shall be disposed of to the satisfaction of the Company.

All manual electrodes shall be properly identifiable up to the time of usage, each electrode being distinguishable by a coding marked near the grip end. Electrodes without a code marking shall not be used. Wire spools shall be stored in cabinets with supplier's wrapping in place and shall remain clearly identifiable up to the point of usage. Unidentifiable wire shall not be used.

Flux shall be handled and stored in accordance with the flux manufacturer’s recommendations, The Contractor shall furnish the Company with manufacturer's datasheets for the flux prior to its arrival at site. Flux shall remain identifiable and traceable. Recycling shall not be permitted.

Vacuum packed electrodes should be used. Basic coated electrodes not supplied in vacuum packs shall be removed from the containers and baked in ovens in accordance with the manufacturer’s instructions. The electrodes shall be transferred to holding ovens set at 150C after baking from where they shall be issued to heated quivers maintained at a minimum temperature of 70C. Duplex stainless steel electrodes shall not be stored in the same heated cabinets as electrodes of other materials. The maximum stacking height shall be four layers. The baking ovens and the holding ovens shall have automatic heat controls and a temperature read-out display. A ‘map’ or other acceptable method shall be employed so as to identify the contents and their location in the baking and holding ovens. Oven internal storage arrangements shall not allow intermixing of different electrodes (manufacturers and/or sizes).

Consumable control shall be such that any basic coated electrodes shall be used within four hours of issue to a quiver. Where this is not possible due to operational reasons, vacuum seal packed electrodes shall be used, (for which the requirement for issue into a heated quiver shall still apply). Those electrodes not used within four hours shall be returned to the baking oven. Electrodes shall be baked a maximum of two times, i.e. one initial bake and one re-bake. The Contractor shall have a system for identification of baked electrodes.

Prior to the commencement of qualification or production welding, whichever is sooner, the Contractor shall submit a consumable handling procedure to the Company for review and approval. Test welding or production welding shall not commence until the consumable handling procedure has been approved by a Company Welding TA Level 2 or higher.

4.2.3 Shielding gases

4.2.3.1 Types

Add the following:

The shielding and purge gas shall be certified as complying with ISO 14175, AWS 5.32 or equivalent. The purity or component concentrations of the gas shall be as specified on the WPS and shall be the same for procedure qualification and production welding. See also section 7.16 for limitations on composition and purity.

4.2.3.2 Storage and handling

Add the following:

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Gases in containers that are unidentifiable shall not be used.

Add the following new section:

4.3 Quality System

The work shall be undertaken only by Contractors that have been approved by the Company specifically for the welding of duplex stainless steel. Approval of Contractors shall be based on Company document GU-225.

The welding Contractor shall maintain and operate a quality system which shall be in accordance with ISO 9001 and SP-1171. A quality system based on alternative standards to those of ISO may be considered for agreement by the Company. All welding and related activities shall satisfy the requirements of ISO 3834-2.. It is recommended to follow the guidelines given in PD CR 13576.

5 Qualification of Welding Procedures for Welds Containing Filler Metal Additives

5.1 Procedure Qualification

Add the following:

The Contractor shall deploy a qualified Welding Engineer with previous field experience of duplex stainless steel welding to have technical responsibility for all welding activities. The qualifications and experience of the Welding Engineer shall be approved by the Company.

WPS proposals for qualification shall be submitted to the Company a minimum of two weeks prior to the proposed date of test welding. The WPS proposals shall be endorsed and signed by the Contractors authorised representative prior to submission. The Company welding TA-2 shall indicate approval of the WPS proposals by endorsing "APPROVED FOR QUALIFICATION", the contract number, the date and signature. Only WPSs so endorsed shall be used for test welding.

Previously qualified welding procedure specifications may be employed subject to the following:

The PQR is fully in accordance with this specification. The WPS is amended to reflect the project specific details. The welding shall be within the essential variables defined in this specification. The WPS and PQR are owned and controlled by the Contractor. The WPS and PQR are approved by the welding TA-2 for each project.

Notes:Provisions for the welding and testing of fillet welds, included in API Std 1104 and this specification shall be taken to apply additionally to full penetration branch welds.

A PQR shall be used only by the Contractor who had direct operational control during production of the test welds. The provisions of ASME Section IX, QW-201 shall be referenced for detailed definition of the Contractor’s responsibility

Any welding procedure qualified to meet project specific requirements for which the Company has paid/reimbursed the cost of qualification shall be owned by the Company. The Company will keep original PQR copies.

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5.2 Record

Add the following:

The PQR shall include the following Documents:

The WPS Approved for Qualification with all the details specified in clause 5.3. The actual welding details with all the details specified in clause 5.3 Material certificates. Consumables certificates. PAMS printout of the welding parameters*. Summary of welding parameters including heat input calculation Pre-heat treatment records (as applicable) PWHT records (as applicable) Visual inspection report. NDT reports. Laboratory test report.

* Welding parameters shall be recorded by means of a calibrated portable arc monitoring system with printout facility.

5.3 Procedure Specification

5.3.1 General

Add the following:

The WPS shall show the following non-technical information:

Date Revision number Contract number Project title Contractors signature and endorsement Client: PDO

5.3.2 Specification information

5.3.2.1 Process

Add the following:

The root and second pass of all full-penetration welds shall be made by the GTAW process. The use of established automatic GTAW systems is permitted. Proposals to employ an alternative root process, such as automatic GMAW, shall require specific Company approval based on pre-qualification trials under conditions comparable to the intended application.

5.3.2.2 Pipe and fitting materials


The materials to which the procedure applies shall be identified. Separate WPSs shall be prepared to cover each specification and grade of pipe or fittings to be welded.

5.3.2.3 Diameters and wall thicknesses


When the use of qualification ranges is agreed by the Company, the following limits shall apply for all diameters and thicknesses:

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Qualified diameter range; when D <323mm, 0.5D to 2 D; when D > 323mm; 0.5D to maximum to be welded.

Qualified wall thickness range, 0.75t to 1.5t. but not < 5mm. For t < 5mm, a change outside the range t to 1.5t

Qualified throat thickness, (fillet weld), 0.75a to 1.5a.

Nominal thickness, t, is dependent on weld configuration and is defined in Appendix A of this specification.

Welds made using fully automatic equipment shall be separately qualified for each combination of pipe diameter and wall thickness.

5.3.2.4 Joint design

Add the following:

The WPS shall indicate the allowable tolerances on each of the joint design details. Permanent backing bars shall not be used.

Joint designs shall be generally as shown in ASME B31.4 and ASME B31.8. Where automatic welding is specified, a U-groove preparation without root gap shall be used. Socket welds shall not be permitted for the attachment of branch connections.

5.3.2.5 Filler metal and number of beads

Add the following:

Details of the filler metal sizes, classification, and manufacturer/brand name shall be stated on the WPS for each pass.

For SMAW, maximum bead width should be restricted to 2.5 times the electrode diameter. For GTAW, a limit should be determined from PQR data. Based on the minimum linepipe thickness of 4.8 mm normally specified for pipelines, joints shall be completed with a minimum of three passes.

5.3.2.6 Electrical characteristics

Add the following:

Where applicable, electrode stick-out, contact tube-to-work distance, and wire feed speed shall be specified for each bead. If pulse welding is used, background current and pulse parameters shall also be specified or a unique program reference included.

5.3.2.7 Flame characteristics


Oxyfuel gas welding shall not be used.

5.3.2.8 Position

Add the following:

WPSs for manually welded linepipe butt joints shall be qualified in the 5G position to cover normal production welding positions. Automatic welds shall be qualified for each position to be used in production. Branches, attachment welds and ancillary piping may be qualified in the production welding position or, to cover all positions, in the 6G position, at the option of the Contractor.

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5.3.2.9 Direction of welding

Add the following:

Except where an automatic process is specified, all positional welds shall be deposited by uphill progression only.

5.3.2.11 Type and removal of line-up clamp

Replace last sentence as follows:

An internal or external line-up clamp shall be used for all girth welds except where it is demonstrated that to do so would be impractical, in which case tack welding may be permitted by Company approval.

An internal line-up clamp shall not be removed until deposition is completed of the first two passes or 4mm thickness of weld, whichever is greater. An external line-up clamp shall not be removed until the root bead is at least 50% complete, equally distributed around the joint.

The minimum number of passes to be deposited before the pipe is lowered off shall be stated.

See also clause 7.3 of this specification.

5.3.2.12 Cleaning and/or grinding

Add the following:

The WPS shall state the methods and types of tools to be used for inter-run cleaning, final weld surface preparation, and treatment to the backside of the weld, if any. See also clause 7.7 of this specification.

5.3.2.13 Pre- and post-heat treatment

Add the following:

The maximum interpass temperatures and temperature control methods shall also be specified.

See also clause 7.11.1 of this specification.

Note: Preheat and PWHT will not normally be specified for duplex stainless steels.

5.3.2.14 Shielding gas and flow rate

Change title to:

5.3.2.14 Shielding/backing gas and flow rate

Add the following:

For root welding of single-sided joints, gas back purge shall be specified. The WPS shall include requirements for flushing prior to commencement of welding and for monitoring of exit gas oxygen content, (see section 7.17 of this specification).

5.3.2.15 Shielding flux

Add the following:

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The type of flux, the AWS flux classification, the manufacturer and brand name and the size shall also be specified.

5.3.2.16 Speed of travel


Speed of travel shall be shown in millimetres per minute or millimetres per second.

Add the following new sections, 5.3.2.17 – 5.3.2.21:

5.3.2.17 Heat input range

Heat Input (kJ/mm) = (Volts x Amps x 60) / (1000 x Welding Speed (mm/min.))

The allowable range of heat input rates to be applied by each welding process for each bead shall be specified.

5.3.2.18 Number of welders

The WPS shall designate the number of root pass welders and hot pass (second pass) welders.

5.3.2.19 Partially complete joint

The minimum number of passes before the joint is allowed to cool to ambient temperature shall be specified. The minimum shall be three passes or one third of the joint whichever is greater.

See also clause 7.14 of this specification.

5.3.2.20 Tungsten electrode for GTAW welding

The AWS electrode class shall be specified in the WPS.

5.3.2.21 Welding technique

For automatic welding, the following shall be specified:

- amplitude of weave;- frequency of weave; and- dwell time.

5.4 Essential Variables

5.4.2 Changes requiring requalification

5.4.2.2 Base material

Replace as follows:

Any change in UNS number. A change in the PREN exceeding –1.5 or +2.5.

In addition to the above for super-duplex grades any change in manufacturer or product form shall be considered an essential variable. A procedure qualified by welding together products from different manufacturers or different product forms shall qualify both the combination and welds between each product.

SP-1097 Page 14 May 2005


5.4.2.3

Delete existing section and replace by:

Any change in bevel dimension outside the tolerance stated in the approved WPS, unless otherwise agreed by the Company. Branch welds shall require separate qualification in accordance with Section 5.7.

5.4.2.4 Position

Add the following:

Any change in the angle of the axis of the pipe greater than 25 from that used for qualification shall constitute an essential variable.

5.4.2.6 Filler metal

Replace existing section, including Table 1, as follows:

The following changes in the qualified WPS shall be considered as essential variables:

a change in the diameter of electrode or filler wire. a change in filler metal classification. a change of filler metal trade name

Subject to the approval of the Company Welding TA-2, a change to a different trade name of solid filler wire may be accepted without re-qualification.

5.4.2.10 Shielding gas and flow rate

Change title to:

5.4.2.10 Shielding/backing gas and flow rate

Add the following:

A change of shielding or backing gas flow rate to one outside the range ± 20% of the average value qualified and specified shall also constitute an essential variable.

Any increase in the oxygen content of the effluent backing gas beyond that qualified shall necessitate re-qualification.

Any decrease in the number of passes before cessation of backing gas flow shall constitute an essential variable.

5.4.2.11 Shielding flux


Any change in classification or trade name constitutes an essential variable.

5.4.2.12 Speed of travel

Add the following:

Any change in the range of qualified speed of travel, or electrode run out length, outside the range ± 15% of that qualified shall constitute an essential variable. See also 5.4.2.13, following.

May 2005 Page 15 SP-1097


Add the following new sections, 5.4.2.13 – 5.4.2.20:

5.4.2.13 Welding current or heat input

Any change in average welding heat input per pass outside the range ± 10% of that qualified and the addition or deletion of pulsating current shall be considered essential variables. The allowable range for volts, and amps and travel speed (2.4.2.12) shall be ± 15% of the individual values determined from the PQR. However, the Contractor shall control these parameters so as to comply with the heat input requirements stated above.

5.4.2.14 Wire feed speed

Any change outside of the range specified on the approved for construction WPS shall constitute an essential variable.

5.4.2.15 Preheat and interpass temperature

Any increase greater than 50C in the specified minimum preheat temperature or any increase in maximum interpass temperature shall constitute an essential variable.

5.4.2.16 Post-weld Heat Treatment

The inclusion or deletion of PWHT or any change in PWHT parameters shall constitute essential variables.

5.4.2.17 Number and sequence of weld beads

Any change in the sequence of deposition shall constitute an essential variable.

5.4.2.18 Removal of line-up clamp

Removal of the line-up clamp at a stage earlier than stated in the approved for construction WPS shall constitute an essential variable.

5.4.2.19 Partially completed joint

Any change in the minimum number of runs before the joint is allowed to cool shall constitute an essential variable.

5.4.2.20 Diameter

See clause 5.3.2.3 of this specification.

5.5 Welding of Test Joints - Butt Welds


Test welding shall be performed under simulated site conditions using full pipe lengths as appropriate unless otherwise agreed by the Company. Where applicable, the clamping, support and back purging arrangements intended for production welding shall be used for the test weld. The longest length of internal purge tubing expected to be required for use with the procedure should be included in the test set-up to confirm that the required purging conditions can always be attained and monitored without affecting weld quality. Set-up details shall be recorded in the test welding record. In order that root oxidation can be assessed under ‘worst case’ conditions, welding should commence as soon as the maximum specified back purge oxygen level is reached.

Sufficient test welds shall be made to extract all the destructive test specimens required for qualification testing. Test welding shall be witnessed by a Company representative having

SP-1097 Page 16 May 2005


a Welding Technical Authority level 3 or higher.. The Contractor’s Welding Engineer who is approved by the Company shall supervise the entire welding procedure qualification process. The Contractor shall give the Company a minimum of 48 hours' notice of the intention to proceed with test welding.

Immediately prior to test welding, the Contractor shall have available at the test site for Company inspection, the following documents:

WPS endorsed "Approved for Qualification". Materials certificates, or verified copies, traceable to the items to be welded. Batch certificates, or verified copies, traceable to the welding consumables. The approved consumable handling procedure.

The Contractor shall have a minimum of one Company-approved calibrated portable arc monitoring system with hard copy facility available at the test site to record welding parameters. No test welding is permissible without recording the welding parameters using a calibrated portable arc monitor.

5.6 Testing Of Welded Joints - Butt Welds

5.6.1 Preparation

Delete the existing section and replace as follows:

Test welds shall be subjected to NDT as detailed in 5.6.1.1, before sectioning for destructive testing in accordance with 5.6.1.2. Any specified post-weld heat treatment shall be completed prior to NDT.

5.6.1.1 Non-destructive testing of test welds

NDT shall be witnessed by a Company Welding TA-3 (or higher) or by a Third Party Inspector nominated by the Company.

The NDT shall consist of the following:

Visual examination Liquid penetrant testing Radiographic testing Ultrasonic testing, where thickness permits.

NDT on all test welds shall be performed with the weld at ambient temperature using equipment and Company-approved procedures that will be employed for production. NDT of a test weld may serve as a qualification test for the NDT procedures.

The acceptance criteria shall be as stated in Section 6 of this specification. Any weld that fails to meet the acceptance criteria shall not be offered for destructive testing. Visual examination of all butt welds shall include the pipe bore surfaces. The degree of oxidation present on these surfaces following welding shall be within the visual acceptance criteria of DEP 30.10.60.31-GEN.

5.6.1.2 Destructive testing of test welds

Following Company approval of the NDT, all test welds shall be sectioned at the locations shown in Figure 3 of API Std 1104 and Figure A of this specification. Sectioning and testing shall be performed at a Company-approved test laboratory.

The Contractor shall appoint a Company-approved agency to witness the destructive testing. This agency shall certify that all tests are made in accordance with API Std 1104 and the additional requirements of this specification. The Company shall have the option

May 2005 Page 17 SP-1097


to witness the destructive testing or to appoint an agency to act on its behalf. All test reports shall be endorsed and signed by the testing organisation, the Contractor, and the Third Party Inspector who witnessed the testing.

5.6.3 Nick-break test

Delete this section.

Add the following new sections, 5.6.6 – 5.6.11:

5.6.6 Macroscopic examination and hardness test

5.6.6.1 Preparation

Specimens shall be prepared for macroscopic examination by grinding or other suitable method to a 600 grit paper finish. The prepared surfaces shall be etched using a suitable etchant to reveal the pass sequence, HAZ, defects etc. Metallographic examination of representative sections shall also be carried out and observations included with the macroscopic examination report to confirm the microstructure of the weld/HAZ and the absence of deleterious phases.

The sections of the weld taken for macroscopic examination and hardness testing shall also be used for ferrite measurement as required in clause 5.6.7 of this specification.

5.6.6.2 Method

The macrosections shall be examined at a minimum magnification of x5. Macro-photographs showing the hardness indentations shall be included in the PQR.

The hardness shall be measured in accordance with ASTM E92, using HV10. For pipe butt welds, the hardness indentations shall be as shown in Figure C of this specification. For pipe of t less than 10 millimetres, the mid-thickness traverse may be omitted.

5.6.6.3 Requirements

The macrosections shall not show defects exceeding the acceptance standards given in Section 6 of this specification. Each specimen shall exhibit a smooth and regular profile and the reinforcement shall blend smoothly with the parent metal. Slight intermittent undercut with a maximum depth of 10% of the pipe wall thickness or 0.4 millimetres, whichever is the smaller, shall be deemed acceptable. Excess penetration shall not exceed the requirements of clause 9.3.6.4 of this specification. Joint misalignment shall not exceed 1.6 millimetres.

The maximum hardness values from each traverse shall not exceed 325 HV10.

5.6.7 Ferrite measurement

5.6.7.1 Preparation

Measurements of ferrite level shall be made on the prepared sections used for macro-examination and hardness measurements.

5.6.7.2 Method

The ferrite content shall be determined by microscopic point counting in accordance with ASTM E562 and Appendix D of this specification, or by a magnetic measurement technique using an instrument calibrated to AWS 4.2 (for DSS only). Ferrite determinations shall be made in the weld metal and both HAZ areas at a depth of 1mm from the inside and from the outside surfaces, or for magnetic techniques, as close to the

SP-1097 Page 18 May 2005


surface as is practicable. Additional checks shall be made in the centre of the unaffected base material on each side of the weld.


Ferrite content determined by microscopic point counting shall be in the range 40 - 60% for the parent material and 35 - 65% in the weld/HAZ regions. The ferrite range for magnetic measurements shall be between 30 – 70 FN. In the event that borderline unacceptable or otherwise doubtful results are obtained using magnetic measurement, a check point-counting determination may be made if agreed by the Company Welding TA-2. If the results of these repeat tests are satisfactory, the ferrite content shall be considered to be acceptable.

5.6.8 Charpy V-Notch Impact Testing

5.6.8.1 Preparation

Each procedure qualification shall include impact testing unless the nominal pipe wall thickness is less than 4.8 mm.

One set of three specimens shall be taken at each of the following positions:

root weld centre line root fusion line (50% intersection of notch) root fusion line + 2 millimetres

When the wall thickness exceeds 20 millimetres, an additional set of three specimens shall be taken at each of the following positions:

cap weld centre line cap fusion line (50% intersection of notch) cap fusion line + 2 millimetres

These requirements are summarised in Figure B of this specification.

Specimens shall be 10 x 10 millimetres full size wherever possible. Where these dimensions are not possible, the largest obtainable standard sub-size specimens shall be extracted.

5.6.8.2 Test temperatures and acceptance criteria

Testing in accordance with ASTM A370 and this specification shall be conducted at -20C or at the minimum design temperature, whichever is the lower. The test temperature shall remain the same for all specimen thicknesses.

For each set of three specimens, only one of the individual values may be below the minimum average energy requirement with an absolute minimum as defined by the minimum individual acceptance criterion.

The acceptance criteria are detailed in the Table below. For other standard specimen dimensions, the acceptance criteria shall be applied pro rata.

Specimen Size, mm Charpy Energy, Joules

Minimum Average Minimum Single

10 x 10 40 30

May 2005 Page 19 SP-1097


10 x 7.5 30 23

10 x 5 20 15

5.6.9 Corrosion Testing

5.6.9.1 Preparation

A coupon specimen of dimensions 5 cm x 5 cm x full wall thickness shall be prepared in accordance with ASTM G48. No flattening of the coupon material shall be carried out. The weld seam shall be located centrally and parallel to one axis. The edges of the specimen shall be rounded to minimise edge effects and the sides ground to 600 grit finish or better. Other surfaces shall be in the "as-finished" condition.

5.6.9.2 Method

A pitting corrosion resistance test shall be conducted in accordance with ASTM G48, Method A using the total immersion ferric chloride test. The specimen shall be degreased, dried and weighed to three decimal places and the weight recorded.

The specimen shall be held in the solution at an angle of 45, with inside surface uppermost. Unless otherwise directed, the test shall be conducted for a period of 24 hours at a temperature of 22C ± 2C. For 'superduplex' grades the test temperature shall be 35C -37C Unless specified otherwise .

On completion of the test period the specimen shall be rinsed, cleaned, dried and weighed using the procedures specified in ASTM G48A.


The specimen shall be examined at a magnification of x20. No pitting shall be visible. Weight loss shall be presented as total weight loss and weight loss per unit area. The latter shall not exceed 0.8mg/cm2.

All samples shall be made available for inspection by the Company.

5.6.9.4 Other corrosion testing

Further testing may be required by the Company where duplex stainless steels are specified for service in environments containing H2S.

5.6.10 Chemical analysis

Chemical analysis shall be conducted of the root run weld metal. The weld metal sample shall be taken from an adjacent or equivalent location to that shown for the impact test specimens in Figure A. The elements required for calculation of the PRE (see Section 4.2.2.1) shall be determined. The PRE value shall exceed the minimum specified for the base material to be welded.

5.6.11 Retests

5.6.11.1 General

If the results of destructive testing are unsatisfactory owing to defective specimen preparation or a localised weld defect, the Contractor shall inform the Company and obtain approval to proceed with retests as detailed below.

SP-1097 Page 20 May 2005


5.6.11.2 Tensile tests and bend tests

If only one tensile or bend specimen does not meet the acceptance criteria, two additional specimens shall be tested. Both of the additional specimens shall meet the acceptance criteria.

5.6.11.3 Hardness tests

If only one hardness result exceeds the specified maximum then three further impressions shall be made in close proximity to that which failed such that they do not mutually interfere. If all of the further tests are below the specified maximum then the test shall be accepted.

5.6.11.4 Charpy v-notch impact tests

If the specified minimum average value has been achieved and more than one specimen is below the specified average value, or one specimen is below the specified minimum individual value, a retest of three further specimens shall be made. All three individual retest values shall equal or exceed the specified minimum average value.

5.6.11.5 Corrosion tests

Retesting of any specimen which fails to meet the pitting and/or weight loss acceptance criteria in the ASTM G48A corrosion test shall be permitted only if failure can be reasonably attributed to test conditions or sample preparation. Where retesting is agreed by the Company, two further specimens shall be prepared and tested. Both of the additional specimens shall meet the acceptance criteria.

5.6.11.6 New procedure requirement

If the test joint fails to meet the minimum requirements, a new WPS proposal shall be established and qualification welding and testing repeated.

5.7 Welding of Test Joints - Fillet Welds

Change title as follows:

5.7 Welding of Test Joints - Fillet Welds and Branch Welds

Delete existing section and replace as follows:

The configuration of fillet weld and branch weld test joints shall be in accordance with the weld details to be used in production and the limitations of section 5.3 of this specification. See also the note under section 5.1.

Test welding shall be witnessed by the Company and shall only commence after the WPS proposal has been approved by the Company and endorsed "APPROVED FOR QUALIFICATION".

5.8 Testing Of Welded Joints - Fillet Welds


5.8 Testing of Welded Joints - Fillet Welds and Branch Welds

May 2005 Page 21 SP-1097


5.8.1 Preparation


Prior to cutting, test welds shall be visually inspected and liquid-penetrant tested. If the weld is deemed acceptable in accordance with the acceptance criteria detailed in Section 6 of this specification it may be offered for destructive testing

Test specimens for macroscopic examination and hardness testing shall be cut from the joint at the locations shown in Figure 10 of API Std 1104. The specimens should be machine cut and one face shall be prepared for macroscopic examination by grinding or other suitable method to a 600 grit paper finish. The prepared surfaces shall be etched using a suitable etchant to reveal the pass sequence, HAZ, defects etc.

5.8.2 Method


Macroscopic examination and hardness measurement shall be carried out in accordance with section 5.6.6.2 of this specification. On full penetration branch welds, ferrite checks shall also be conducted in accordance with section 5.6.7.2 of this specification.

5.8.3 Requirements


Macroscopic examination, hardness and ferrite requirements shall be in accordance with clauses 5.6.6.3 and 5.6.7.3 of this specification.

Add the following new sections5.9 – 5.11:

5.9 Welding of Test Repair Welds

Repair welding procedures shall be prepared and qualified for each type of repair to be performed in accordance with sections 5 and 10 of this specification. The initial girth weld shall be welded to the appropriate qualified WPS. The maximum depth of partial penetration repair welds shall the lesser of 0.5t or t-6 mm, (see also section 10.16). Where the execution of single run repairs has been agreed (see section 10.1.1) separate qualification shall be made. Back-welded repairs are not permitted. Test repair weld excavations shall be located as shown by the appropriate diagram in Figure 1 of BS 4515 Pt. 2.

5.10 Testing of Repair Welds

5.10.1 Preparation

Each repair shall be of sufficient length to provide the specified number of specimens for destructive testing. Non-destructive and destructive testing of the repair weld shall be performed as required in (5.6) and (10.1.3) except where modified below.

5.10.2 Method

Provided the repair weld procedure is representative of the original weld qualification, destructive tests shall be as listed below. Otherwise full procedure qualification tests shall apply as specified in section 5.6 of this specification’.

- 1 transverse tensile, (5.6.2);- bend test, (5.6.4 or 5.6.5);

SP-1097 Page 22 May 2005


- 1 macro-hardness test, (5.6.6) at the locations shown in Figure 8 of BS 4515 Part 2;- ferrite measurement (5.6.7), which for partial penetration repairs shall include

measurements made in the new HAZ formed in the original weld;- Charpy testing (5.6.8) at the locations shown in Figure 4 of BS 4515 Part 2;- corrosion testing (5.6.9), to include the junction of new and original weld metal.

5.10.3 Requirements

The acceptance criteria shall be as for the original welding procedure qualification.

5.11 Records

The procedure qualification record shall include the following:

Approved for qualification WPS

Print-outs from the portable arc monitoring system for each pass Visual inspection and NDT reports Heat treatment reports Original laboratory test certificates, including macrophotographs Original or verified copies of materials certificates for the test coupon materials Original or verified copies of batch certificates for the filler materials and

shielding/backing gases employed for test welding.

The PQR shall be submitted to the Company for review and approval with the revised WPS for production welding.

6 Qualification of Welders

6.1 General

Add the following:

Welders who weld the procedure qualification test coupons, which are satisfactory, shall be deemed as being qualified.

Welders shall have a valid Company qualification within the validity defined in this specification or they shall be qualified on contract materials using the Approved For Construction WPS. Qualification shall be valid for a period of six months. This period may be extended by a further six months when it can be shown by NDT from production welding that the welder has produced satisfactory welds using the approved for construction WPS. After 12 months the welder shall be re-qualified, unless otherwise agreed by the Company’.

Welders shall be re-qualified when the Company has reason to question the welder's ability to make welds that meet this specification.

For butt welds, welders shall be qualified by visual examination, radiographic testing, bend testing and macro-examination. Where automatic welding has been used, ultrasonic testing shall also be undertaken where section thickness permits.

For branch welds and fillet welds, welders shall be qualified by visual examination, liquid penetrant testing, and macro-examination.

May 2005 Page 23 SP-1097


6.2 Single Qualification

6.2.1 General

Delete first sentence and replace as follows:

The use of segments of pipe nipples shall not be permitted. Each of the two pipe nipples used to make the test weld shall be a minimum length of D or they shall be of sufficient length to accommodate the alignment device being used, whichever is greater.

6.2.2 Scope

Delete items a., b., c., d., e., f., and g. and replace with the following:

For sour service applications, as determined by the Company in the Contract document, the limits of welder qualification are the essential variables of the WPS. In such cases, any change that necessitates re-qualification of the WPS shall be cause for re-qualification of welders to the new, approved WPS unless the Company agrees that the variable that has changed has no effect on a welder's performance. Otherwise, the following essential variables shall be applied for welder qualification:

(a) A change from one welding process to another or a change from manual to automatic or vice versa.

(b) A change in joint thickness to more than twice the thickness of the test joint.(c) A change in pipe or branch diameter outside the range 0.5D to 2 D, where D is the test

pipe diameter.(d) A major change in joint configuration, e.g. ‘U’ to ‘V’ preparation(e) Any change in welding position, except that qualification in the 6G position shall

qualify all positions.(f) A change in welding progression from uphill to downhill or vice versa.(g) For manual welding electrodes, a change from one coating type to another(h) Any change in the nominal composition of the shielding gas.

6.3 Multiple Qualification

6.3.1 General

This clause of API Std 1104 shall not be applicable.

6.3.2 Scope

This clause of API Std 1104 shall not be applicable.

6.4 Visual Examination

Delete existing section and replace with the following:

Performance of visual examination and the acceptance criteria shall be as defined in section 9 of this specification.

6.5 Destructive Testing

6.5.1 Sampling of test butt welds

Delete existing section, including Table 3, and replace with the following:

After satisfactory radiographic testing, the test weld shall be sectioned for macro-examination in accordance with Section 5.6.6. Hardness testing may be omitted. The

SP-1097 Page 24 May 2005


number of macro-sections shall be two per welder's portion. The acceptance criteria shall be as defined in Section 9.

6.5.2 Tensile strength, nick-break and bend test procedures for butt welds

Add the following:

The specified tensile strength and nick-break tests may be omitted.

6.5.6 Sampling of test fillet welds


6.5.6 Sampling of Test Fillet Welds and Branch Welds

Add the following:

See also the note in section 5.1 of this specification.

Prior to cutting, in addition to the visual examination specified in clause 6.4, the test welds shall be liquid penetrant tested and shall meet the requirements of section 9 of this specification.

6.5.7 Test methods and requirements for fillet welds


6.5.7 Test Methods and Requirements for Fillet Welds and Branch Welds


The fillet weld samples shall be prepared and subjected to macro-examination in accordance with section 5.8 of this specification.

6.6 Radiography - Butt Welds Only

6.6.1 General


The qualification butt weld shall be examined by radiography in addition to the destructive testing specified in API Std 1104 section 6.5 and this specification. Provided section thickness is sufficient, ultrasonic testing shall also be performed on test welds where any bead has been deposited by an automatic process.

6.6.2 Inspection requirements

Add the following:

The test weld shall meet the requirements of API Std 1104 as modified by this specification.

6.7 Retesting


If the test weld does not meet the specified acceptance criteria, the welder may carry out two repeat tests. Both of the repeat welds shall meet the specified acceptance criteria. Failure of one or both repeat welds shall result in disqualification of the welder until such

May 2005 Page 25 SP-1097


time as the Contractor can demonstrate to the Company by records that satisfactory training has been received. The welder may then be presented for further qualification testing.

6.8 Records

Add the following:

The Contractor shall maintain the records of the tests and test results of each welder. The Contractor shall assign each welder a unique identification number, letter, or symbol to ensure traceability to specific welds. If a welder ceases to work for the Contractor, the unique identification shall not be re-assigned to another welder.

7 Design and Preparation of a Joint for Production Welding


7 Production Welding

7.1 General


Limitations imposed by the essential variables detailed in this specification and API Std 1104 shall be adhered to in production welding. No production welding shall be carried out before the WPSs have been endorsed as 'Approved for Construction' by the Company and the welders qualified to weld using the approved WPSs.

The approved WPSs shall be available at the construction site with either the welder, the welding supervisor, or the welding inspector.

Welding operations shall not be performed when the welding inspector is not present at the construction site.

The preparation and welding of pipeline components shall be in accordance with the qualified and approved WPS.

Fusion faces and the surrounding surfaces within a minimum of 25 millimetres of the joint shall be free from heavy scale, moisture, oil, paint, or any other substance which may have a deleterious effect on the weld quality or progress.

If welding works are to be performed in the vicinity of equipment already installed, adequate protection shall be provided to prevent damage from weld spatter.

Arcs shall be struck only on fusion faces or on striking plates provided as an aid to arc starting. Stray arc strikes shall be removed by grinding. The ground area shall be liquid penetrant tested and thickness checked. Where the thickness is below the specified minimum, the section of pipe shall be removed. The Contractor shall ensure a good earth connection and periodically examine the condition of the earth cables and attachments. Any arcing from a poor connection shall be treated as an arc strike. Connections shall be made to the work by clamps having stainless steel contact surfaces. Earth cables shall not be welded to pipeline components.

A Company-approved circular cap to prevent entry of foreign material shall be used to cover open ends of the pipe when interruptions to work expected to last two or more hours occur. All open ends of pipe strings shall be capped off and sealed when welding is completed.

SP-1097 Page 26 May 2005


7.1.1 Handling and storage

7.1.1.1 General

All necessary precautions shall be taken throughout fabrication to minimise contamination of duplex stainless steel materials resulting from direct contact with carbon steels, exposure to ferrous dust, swarf or other debris and from residual deposits on or near fusion faces. Equipment used for grinding and cleaning of edge preparations shall be dedicated for stainless steel work. Wire brushes shall be of stainless steel. Precautions required for handling equipment and line-up clamps are included in Clause 4.1 of this specification. General precautions to be applied during the storage of duplex stainless steels and in handling linepipe are outlined in Clauses 7.1.1.2 and 7.1.2.3, following.

Surface oxidation or metallic contamination which will not respond to washing or degreasing treatments shall be removed using power tools or by a pickling treatment. Pickling procedures shall be subject to prior approved by the Company. The Contractor shall ensure the safe use and disposal of chemical solutions and the thorough cleaning and drying of pipework. Washing shall be performed with potable water.

7.1.1.2 Storage

a) Components stored in an open site or within a fabrication workshop shall be protected from environmental contamination.

b) Duplex stainless steels shall be clearly identified and segregated from other stored materials.

7.1.1.3 Pipe handling

c) Supports, rollers and other pipe handling equipment shall be of compatible material or shall be suitably lined to prevent damage or contamination of the pipework.

d) Slings and supports for lifting duplex stainless steel pipe and assemblies shall be of Nylon or similar compatible material.

e) Pipe handling by means of hooks in pipe ends shall not be permitted.

7.1.2 Weather protection

f) Work shall not be performed when the weather and/or degree of protection does not permit satisfactory workmanship.

g) Enclosures giving adequate protection to the weld area at all times from wind, rain and moisture shall be provided. In windy conditions the pipe ends shall be sealed to prevent through draughts.

h) Weld surfaces shall be thoroughly cleaned and dried before welding. Moisture shall be removed by means of blowers, or in exceptional cases a heating torch may be used provided no signs of surface oxidation are allowed to develop.

7.2 Alignment


The pipeline components shall be firmly supported in both the vertical and horizontal plane and no welding shall be carried out until the alignment specified in the approved WPS has been achieved.

Any misalignment shall be reduced to a minimum by rotation of the pipe to achieve the best fit. Hammering or heating of the pipe shall not be permitted.

If the offset exceeds 1.6 millimetres, provided that it is caused by dimensional variations within the specified tolerances, or where alignment of two pipeline components of

May 2005 Page 27 SP-1097


different nominal thickness and the same outside diameter is required, joint design shall be in accordance with ASME B31.4 or B31.8. Any taper shall not be steeper than 1 in 4.

When a pipe with one longitudinal seam is used, this seam shall be within the top 120 of the circumference. The longitudinal seams of consecutive pipes shall be offset by at least 45.

7.3 Use of Line-Up Clamp for Butt Welds


Internal line-up clamps should be used wherever possible and their design shall be such as to allow the introduction and containment of root purging gases, as required in clause 7.17. External line-up clamps may be used for linepipe less than 150 NB, for tie-in welds and for special welds, such as connections to valves, flanges and fittings.

Root bead segments used with external line-up clamps shall be cleaned, feathered at each end, and visually inspected prior to completion of the root pass. Any segment, which does not meet the acceptance criteria of Section 9 of this specification, and API Std 1104 shall be removed and re-deposited before completion of the root pass.

Pipe shall not be moved or lowered off until the second pass has been completed.

Where an internal or external line-up clamp cannot be used, alignment may be achieved using tack welds. Tack welds shall be temporary bridge or bullet tacks using suitable duplex stainless steel material. Welding parameters shall be in accordance with the appropriate fill pass. Tack welding shall be performed only by welders qualified to weld with the WPS. The tack welds shall be removed by grinding as welding progresses around the joint.

Fully penetrating root tacks shall not be allowed.

7.4 Bevel

7.4.2 Field bevel


Component ends shall normally be bevelled by machining or grinding. Preparation of weld edges by plasma cutting is permissible provided a machine guided torch is used. Edges shall be left free of slag and the cut surface shall be ground to a smooth bright uniform finish with the removal of a minimum of 0.5 millimetres of metal.

The new bevel shall be visually examined and liquid penetrant tested using a Company-approved procedure. Burns, small score marks, indentations, other imperfections, and linear indications shall be unacceptable and the bevel shall be re-prepared. Repair by welding shall not be permitted. Edges shall be free from slag, spatter, dirt, grease or other foreign matter which may affect weld quality. Acetone may be used for surface cleaning.

Where pipes are cut, pipe markings shall be transferred to the off-cut in order to maintain identification.

7.7 Cleaning Between Beads

Delete, ‘When automatic or semi-automatic welding is used’ and replace with the following:

For all types of welding

SP-1097 Page 28 May 2005


7.8 Position Welding

7.8.2 Filler and finish beads

Replace last sentence of first paragraph as follows:

The weld metal reinforcement at the cap shall not exceed the requirements of clause 9.3.13 of this specification.

7.10 Identification of Welds


Prior to commencing the root pass, the welder shall clearly mark the pipe adjacent to the weld with the symbol or identification assigned to him. Where tack welding has been approved by the Company, no marks shall be made for the tack welding.

Marking shall be made with weather-proof chalk, paint, chloride-free crayon, or pen. Die stamps shall not be used. The root pass welder shall make a mark at the top of the pipe. Where two welders make the root pass, they shall each make a mark at the top of the pipe on the side where they are about to weld. Subsequent welders shall mark the pipe below the first code in the sequence which they work. The identification marks shall not be removed until the welds have been inspected both visually and non-destructively.

7.11 Pre- and Post-Heat Treatment


7.11.1 Preheat and interpass temperature control and measurement

Preheat will not normally be required by the WPS. If welding is likely to be performed below 15C or condensation of moisture on the weld area is possible a minimum preheat of 50C shall be applied to a minimum bandwidth of 75mm either side of the joint. Acceptable methods of pre-heating are electrical resistance heaters or oxy-propane rosebud torches. Welding or cutting torches shall not be used.

The maximum preheats and interpass temperature shall be 150C, unless stated otherwise on the WPS. Temperature measurement shall be by thermocouple, thermomelt crayon, contact pyrometer or a combination of these. Thermomelt crayons shall not be applied within the bevel area.

7.11.2 Post-weld heat treatment

Post-weld heat treatment will be specified only in exceptional circumstances. Individual requirements and procedures shall be agreed with the Company as necessary.

Add the following new sections, 7.12 – 7.16:

7.12 Separation of Girth Welds

The minimum allowable distance between girth welds shall be D or 500 millimetres whichever is the larger. In any 3m length of pipe a maximum of two welds is allowed unless specified otherwise on the approved construction drawings. Welds of branch connections and attachments shall not overlap main seam welds unless approved by the Company.

May 2005 Page 29 SP-1097


7.13 Weld Interruption

Interruption of welding should be avoided. Where interruption is unavoidable, a minimum of three passes or one third of the joint thickness, whichever is greater, shall have been deposited. On resumption of welding any preheat requirements specified in the approved WPS shall be applied.

7.15 Weld Finishing

Welds shall be left as welded and shall not be treated with a flame torch or other mechanical means to change their appearance other than cleaning and dressing operations specified in the WPS. Welds shall not be peened.

When fabrication is completed, all surfaces adjacent to the welds shall be cleaned of spatter, burrs, and other imperfections which could interfere with radiographic or ultrasonic inspection.

7.16 Shielding and Backing Gas

Argon, Helium or Argon/Helium mixtures of at least 99.995% purity shall be used as shielding and backing gas. Argon based gas mixtures containing carbon dioxide may be used for the GMAW process. Gas mixtures containing nitrogen additions may be used subject to the approval of the Company. Hydrogen additions are not permitted.

Unless otherwise approved, gas back purge shall be maintained during the welding of all full penetration butt joints until a minimum of 6 mm. thickness of weld metal has been deposited. Continuation of back purging for further layers may be necessary, subject to the root weld inner surface meeting the specified visual acceptance criteria, as determined in procedure qualification. The same criteria shall be applied to confirm the acceptable maximum depth of partial penetration repair welds.

Flushing with backing gas shall be carried out before welding. The oxygen content of the exit gas shall be monitored using suitable oxygen measuring equipment and welding shall not commence until a level of 0.2% or less is attained. Monitoring shall be continued during welding to ensure that this limit is not exceeded.

8 Inspection and Testing of Production Welds

8.2 Methods of Inspection


Welds shall be evaluated to the requirements of Section 9 of API Std 1104 and this specification. Written NDT procedures in accordance with Section 11 of API Std 1104 shall be approved by the Company (by an Inspection TA-2) prior to test or production welding as applicable. The procedures shall be in accordance with Section 11 of API Std 1104 and this specification. Company approval shall be based on qualification tests which may be carried out as part of the Welding Procedure Qualification testing, (see Clause 5.6.1.1).

The primary NDT method shall be X-ray radiography using Class 1 film, (D4 or equivalent). Ultrasonic and liquid-penetrant examination may supplement radiography and shall be used to interpret doubtful indications in the radiographs or for welds inaccessible for radiography.

8.3 Qualification of Inspection Personnel


SP-1097 Page 30 May 2005


Welding inspection personnel shall hold a valid qualification of one of the following:

CSWIP 3.2, 10 years experience of which at least 2 years in DSS welding inspection AWS SCWI, 10 years experience of which at least 2 years in DSS welding inspection Other qualification agreed by the Company as equivalent to the above.

8.4 Certification of Non-Destructive Testing Personnel

8.4.1 Procedures


All personnel shall be qualified and certificated for the method of NDT to be carried out in accordance with ISO 9712. The roles and responsibilities of NDT personnel shall be as defined in the levels of competence in ISO 9712. Personnel certified to ASNT Level II in accordance with ASNT-TC-1A by examination are acceptable provided that the certifying Level III NDT Engineer has been approved by the Company. The Company approved Level III NDE Engineer (full time employee of NDE Company) shall continuously (monthly) monitor the performance of NDE Personnel certified to ASNT Level II and shall take corrective measures whenever the performance of ASNT Level II technicians is not satisfactory.

If, in the opinion of the Company, welding examination or non-destructive examination personnel fail to perform to a satisfactory standard they shall be disqualified from the works until such time that it can be demonstrated by the Contractor that they have achieved a satisfactory standard by undertaking, at the Contractor's expense, a test by a third party agency approved by the Company.

Add the following new sections, 8.5 and 8.6:

8.5 Extent of Inspection and Testing

Prior to welding, the Contractor shall examine free-issue materials for damage and compliance with the relevant materials specification. This examination shall include a review of the materials certificates. Items supplied without materials certificates shall not be used without written Company approval. All damage and discrepancies shall be reported immediately to the Company. After signed acceptance by the Contractor, any discovered damage shall be the responsibility of the Contractor.

During production welding the welding parameters shall be checked against the approved WPS. Monitoring frequency shall be specified in the Contractor's inspection and test plan.

Radiographic frequency for all pressure ratings shall be 100%.

All fillet welds shall receive liquid penetrant examination.

The Company shall have the final disposition on any weld. Any weld not accepted by the Company shall be rectified in accordance with API Std 1104 and this specification.

8.6 Records

The Contractor shall generate a weld history sheet for every weld which shall contain the following information:

Weld number Isometric and line number Materials specification and identification The WPS employed The welder(s)' identity symbols

May 2005 Page 31 SP-1097


Date welded Visual inspection disposition NDT reports where applicable (to be attached to the weld history sheet) Type of repair, if applicable, and WPS NDT reports for repairs (to be attached to the weld history sheet) PWHT if applicable (chart to be attached to the weld history sheet) Batch number of consumables employed

9 Acceptance Standards for Non-Destructive Testing

9.1 General

Add the following:

All welds shall be visually inspected and cracks, craters, pinholes, weld spatter, residual slag, or arc strikes shall not be acceptable. Wherever accessible, the extent of oxidation on the root and HAZ surfaces of single-sided welds shall be assessed for comparison with the visual acceptance criteria of DEP 30.10.60.31-Gen. The use of a crawler camera or other remote system should be considered for the examination of production welds.

9.3 Radiographic Testing

9.3.1 Inadequate Penetration


This type of defect shall be unacceptable.

9.3.2 Inadequate penetration due to high-low

Replace existing section, including Figure 14, as follows:


9.3.3 Incomplete Fusion



9.3.6 Burn-Through

Delete sub-sections 9.3.6.2 and 9.3.6.3. Replace with new sub-section 9.3.6.2.

9.3.6.2 Acceptance Criteria


Any amount of burn-through shall be unacceptable, irrespective of pipe diameter.

9.3.8 Slag Inclusions

6.3.8.1

Add the following:

Tungsten and copper inclusions shall be treated as slag inclusions for the purposes of assessment.

SP-1097 Page 32 May 2005


9.3.9 Cracks


Cracks of any type shall be unacceptable.


9.3.13 Excess Reinforcement and Penetration

Weld reinforcement, when measured from the adjacent parent material surface, shall not exceed the following values:

Wall thickness(mm)

External weld reinforcement(mm)

6.4 and under 1.6

6.4 - 12.7 2.5

Over 12.7 3.0

Internal protrusion of the weld root shall not exceed 1.5mm. When measuring internal protusion, the line of the pipe bore outside the HAZ should be taken as the reference. Local profile changes adjacent to the fusion line should be discounted.

9.4 Magnetic Particle Testing


9.5 Liquid Penetrant Testing

9.5.2 Acceptance standards

Delete existing section and replace with the following:

Relevant linear indications shall be unacceptable.

May 2005 Page 33 SP-1097


9.6 Ultrasonic Testing

9.6.2 Linear indications

Delete item a. and replace with the following:

a. All linear indications interpreted as cracks shall be unacceptable.

Delete item b. and replace with the following:

b. All linear indications (other than cracks) interpreted to be open to the surface shall be unacceptable.

10 Repair and Removal of Defects

10.1 Defects Other Than Cracks

10.1.1 Authorisation for repair


Welds containing unacceptable defects shall be repaired only if approved by the Company. A weld with unacceptable defects may be repaired only once. If the repair is unacceptable then the complete weld and HAZ shall be removed.

Root sealing runs shall not be permitted. Single run repair welds may be permitted subject to Company approval.

All repairs shall be performed in accordance with a separately qualified repair welding WPS and shall be executed by qualified welders. The repair welding WPS may be identical to, but separate from, the original welding procedure with the addition of the following:

Method of defect removal NDT requirements to determine complete removal of defect

The repair welding procedure shall be qualified in accordance with sections 5.9 and 5.10 of this specification on a full-thickness girth weld.

10.1.2 Removal and preparation for repair


Defects necessitating repair shall be entirely removed to sound metal. All slag and scale generated shall be removed.

The removal of weld metal or portions of the parent material may be done using machining or grinding. Thermal gouging methods shall not be used. Repair excavations shall be smoothly contoured and tapered, having a minimum included groove angle of 50. The repair weld grooves shall be visually and liquid penetrant inspected prior to rewelding.

The total repair length shall not exceed 40% of the total weld length. For partial penetration repairs, the maximum length of a single repair portion shall be 30% of the total weld length. For full penetration repairs, the maximum length of a single repair portion shall be 20% of the total weld length. Groove taper shall be included in the measurements.

SP-1097 Page 34 May 2005


10.1.3 Testing of Repairs

Add the following:

All repairs which require excavation and rewelding shall be re-radiographed. The radiograph shall extend for a distance of 50 millimetres beyond either end of the repaired area.

10.2 Authorisation and Procedure for Repair of Cracks

Delete this section, including items a., b., c., d., e and replace with the following:

For cracks, other than crater cracks, the complete weld and HAZ shall be removed.

11 Procedures for Non-Destructive Testing

11.1 Radiographic Test Methods

11.1.1 General


Radiographic testing shall be performed in accordance with ISO 1106-3, Class B. The radiation shall be X-ray. The technique shall be film outside, source of radiation inside. Where the source of radiation cannot be located inside the pipe, the Company may agree to use of the film and source of radiation outside: double wall single image technique.

The Contractor shall qualify a radiographic testing procedure prior to testing production welds by producing radiographs that comply with this specification. These shall be retained for reference during production and should be suitable both for confirmation of radiographic quality and for assessment of questionable root profile features (weld protrusion, concavity etc.) from density measurements.

Note: Radiographic testing procedure qualification may be undertaken on test welds produced for welding procedure qualification.

11.1.2.3 Other imaging media


11.1.3 Exposure geometry

11.1.3.1 Film radiography

Delete the third paragraph, including the formula and definitions, and replace with the following:

The minimum source-to-specimen distance shall be calculated in accordance with ISO 1106-3 for Class B radiographic testing.



11.1.4 Type of penetrameters


IQIs shall be wire type, (stainless steel or equivalent).

May 2005 Page 35 SP-1097


11.1.5 Selection of penetrameters

11.1.5.1 Hole type penetrameters


Wire-type IQIs shall be used.

11.1.5.2 Wire-type penetrameters


For production radiographic testing, IQI selection, number, location, and appearance in radiographic images shall be in accordance with ISO 1106-3 and ISO 1027.

For radiographic procedure qualification, IQIs shall also be placed on the surface facing the source of radiation. The specified sensitivity requirement shall be achieved on the source side IQIs. The sensitivity achieved on the film side IQIs shall be recorded for comparison and used for evaluating production radiographs.

11.1.6 Placement of penetrameters



11.1.9 Storage of film and other imaging media



11.1.10 Film density

Change title to:

11.1.10 Film density and sensitivity

11.1.10.1Film density


The minimum density shall be 2.0. The maximum density shall be 3.5 where adequate interpretation can be achieved with the viewing screen.

11.1.10.2Film viewing equipment


Illuminators shall comply with the requirements of ISO 5580.


11.1.10.4Sensitivity

The sensitivity shall be 2% or better.

SP-1097 Page 36 May 2005


11.1.11 Image processing


Film shall be processed, handled, and stored such that the images are interpretable for at least 5 years after they are produced.

11.2 Magnetic Particle Test Method


11.4 Ultrasonic Test Method

Add the following note:

Note: Special techniques are required for ultrasonic testing of duplex and super duplex stainless steels. These shall be developed by the Contractor and agreed by the Principal prior to use.

12 Automatic Welding


Requirements for automatic welding are included in the preceding sections of this specification.

13 Automatic Welding Without Filler-Metal Additions


Welding without filler metal addition is not permitted.


14 Documentation

14.1 General

The Contractor shall maintain a record system which ensures weld traceability. The Contractor shall be responsible for compiling the following document packages which shall be submitted to the Company upon completion of the works:

(a) Copy of approved Welding Procedure Register Copies of approved WPSs Copies of approved repair WPSs Copies of all supporting PQRs List of approved welders and their identification List of Company welders' cards Copies of the Company welders' cards List of approved NDT operators Copies of NDT operator qualification certificates List of Company-approved deviations to the Code and this specification Copies of Company-approved deviations to the Code or this specification List of consumable batch certificates Copies of consumable batch certificates List of materials certificates Copies of materials certificates List of test equipment

May 2005 Page 37 SP-1097


Copies of calibration certificates

(b) Certificate of Compliance List of as-built drawings As built drawings showing unique weld numbers List of weld history sheets Copies of weld history sheets which shall show for each weld

weld number isometric and line number material specifications and identification the WPS employed the welders' identity symbols date welded visual inspection disposition NDE reports where applicable (to be attached to weld history sheet) type of repair, if applicable, and WPS NDE reports for repairs (to be attached to weld history sheet) PWHT if applicable (chart to be attached to weld history sheet) batch number of consumables employed

Radiographs - indexed and stored in a fireproof container List of site test records Copies of site test records List of non-conformances/corrective actions issued during external or internal audits Copies of non-conformances/corrective actions issued during external or internal

audits

14.2 Certificate of Conformity

On satisfactory completion of the piping work, the Contractor (or Manufacturer) shall issue a declaration of compliance with this specification. The format of “Declaration of Compliance” is shown in appendix E. The “Declaration of Compliance” shall be signed by the Contractor‘s QA/QC Engineer who is approved by the Company for the contract.

Appendices to API 1104

A Alternative Acceptance Standards for Girth Welds

A1 General

Add the following:

This Appendix shall be applied only when specified by the Company.

B In-Service Welding

Delete this Appendix in its entirety.

SP-1097 Page 38 May 2005


Figure A - Location of Macrosection and Impact Test Specimens

May 2005 Page 39 SP-1097


Figure B - Orientation and Location of Charpy Impact Specimens

SP-1097 Page 40 May 2005


Figure C - Hardness Indent Locations

0.5 X LEG LENGTH

1.5 0.5 mm+-

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X

X X X X X

Hardness indentations in the HAZ spaced at 0.5mm

0.5t

One indentation of every set of 3 shall be as close to the fusion line as possible but shall not intersect it

1.5 0.5 mm+-

1.5 0.5 mm+-

X X X

X X X

X X X

May 2005 Page 41 SP-1097


Appendix C References

In this specification, reference is made to the following publications:

Notes:(1) See also additional references listed in API 1104 Section 1.3.(2) Unless specifically designated by date, the latest edition of each publication shall be used together with any amendments.

PDO Standards

Technical Authorities System

Specification for Duplex Stainless Steel Linepipe

Guidelines for the Approval of Contractors for the Fabrication of Duplex Stainless Steel

Guideline for Granting Technical Authority System

Specification for Welding of Duplex Stainless Steel Piping

Quality Assurance Specification for Engineering Works

Offshore Pipeline Engineering.

ERD-00-02

SP 1189

GU-225

GU-272

SP-1096

SP-1171

SP-1211

Shell Group StandardsOxidation of Stainless Steel Weldments

Welded and Seamless Duplex and Super Duplex Stainless Steel Line Pipe (Amendments/supplements to API Spec. 5LC)

DEP 30.10.60.31-Gen

DEP 31.40.20.34-Gen

American StandardsPipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids

Gas Transmission and Distribution Piping Systems

Boiler and Pressure Vessel Code, Section IX, Welding and Brazing Qualifications

ASME B31.4

ASME B31.8

ASME IX

Specification for CRA Linepipe

Welding of Pipelines and Related Facilities, Eighteenth Edition, May 1994

API Std 5LC

API Std 1104

Standard Test Methods and Definitions for Mechanical Testing of Steel Products

Methods of Preparation of Metallographic Specimens

Standard Test Method for Vickers Hardness of Metallic Materials

Standard Test Method for Determining Volume Fraction by Systematic Manual Point Count

ASTM A370

ASTM E3

ASTM E92

ASTM E562

SP-1097 Page 42 May 2005


Standard Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by the Use of Ferric Chloride Solution

ASTM G48

Sulphide Stress Cracking Resistant Metallic Materials for Oilfield Equipment

NACE MR0175

British StandardsWelding of Steel Pipelines on Land and Offshore, Parts 2

Implementation EN 729 on quality requirements for fusion welding of metallic materials

BS 4515

PD CR 13576

International StandardsRadiographic Image Quality Indicators for Non-Destructive Testing - Principles and Identification

Recommended Practice for Radiographic Examination of Fusion Welded Joints - Part 3: Fusion Welded Circumferential Joints in Steel Pipes of up to 50 mm Wall Thickness

Quality requirements for welding - Fusion welding of metallic materials - Part 2: Comprehensive quality requirements

Non-Destructive Testing - Industrial Radiographic Illuminators – Minimum Requirements

Quality Systems - Model for Quality Assurance in Design, Development, Production, Installation and Servicing.

Non-Destructive Testing - Qualification and Certification of Personnel

Welding Consumables - Shielding Gases for Arc Welding and Cutting

Welding Co-ordination - Tasks and Responsibilities

ISO 1027

ISO 1106-3

3834-2 (Note 1)

ISO 5580

ISO 9001

ISO 9712

ISO 14175

14731 (Note 2)

Note 1 Also published as EN 719Note 2 Also published as EN 729

May 2005 Page 43 SP-1097


Appendix D Determination of the Volume Fraction of Ferrite in Duplex Stainless Steel by Systematic Point Count

1. Scope

This Appendix is taken from Appendix 2 of DEP 31.40.20.34-Gen and specifies the requirements for estimating the volume fraction of delta ferrite in duplex stainless steel by systematic point counting on transverse metallographic sections. The procedure is a specific interpretation of ASTM E562, which should be referenced for additional background and definition of detail as noted.

2. Basis of Method

The method involves the superimposition of a test grid over an image, produced by an optical light microscope, of the appropriate microstructural area. The number of grid points falling within delta ferrite are counted and divided by the total number of grid points, to yield a point fraction which represents an estimate of the volume fraction of delta ferrite present within the field of view. The average point fraction taken over a number of appropriately selected fields gives an estimate of the volume fraction within the region sampled.

3. Terminology

i. Point count - the number of grid points which lie within areas of a specific phase (in this case delta ferrite).

ii. Point fraction (Pp) - the point count divided by the total number of points in the test grid.

iii. Volume fraction (Vv) - the volume of a specific phase per unit volume, expressed as a fraction.

4. Test Piece Preparation

Planar sections shall be taken through the parent material or the weldment, as relevant. Sections shall be perpendicular to the material surface and transverse to the welding direction, when relevant. Each weld sample shall section the whole of the weldment and HAZ and an area of parent material on either side of the weld. Preparation of the test pieces shall be in accordance with standard metallographic techniques, such as described in ASTM E3. It is recommended that the last grinding stage should be with 600 grit, or finer, abrasive and the final polish should be with 1m, or finer, abrasive, e.g. diamond paste.

The test piece shall be etched electrolytically in 40% KOH solution, i.e. 400 g KOH in 1000 ml of solution made with distilled water. Etching shall be carried out in a container of sufficient size to allow immersion of the test piece in the etch at a distance of 100 mm from the platinum cathode. Electrical contact between the test piece and power source may be made by means of a suitably shaped conducting probe.

Acceptable contrast may be obtained at an anode/cathode voltage that generates a current density of 1 amp/cm2 for a period of 2-5 seconds, but trials may be necessary to determine the most appropriate conditions for a particular test piece. It may be noted that the contrast between the delta ferrite and austenite phases will probably vary through the weldment.

5. Area Selection

The areas in which measurements have been made shall be specified precisely, as should the exact measurement locations. The weld pass shall be stated, e.g. root, cap, fill - preferably with a number, as shall the area which has been measured, i.e. weld metal, HAZ

SP-1097 Page 44 May 2005


or parent material. Where possible it should be indicated whether the area has been re-heated or is as-deposited. Any uncertainty shall be noted. The location of measurements shall be recorded on a sketch or photograph of the section.

6. Apparatus

An optical light microscope which projects an image of the magnified microstructure onto a viewing screen shall be used, preferably with graduated x and y translation controls. The magnification shall be selected such that the ferrite particles have an average dimension approximately one half of the grid point spacing. This should be judged visually in more than one field of view, before measurements are made.

Note: For many weldment microstructures, particularly in re-heated areas, a magnification in the range x 500 - x 1000 is suitable.

The test grid shall be marked on a transparent sheet which shall be superimposed on the magnified image of the microstructure. The grid shall consist of a square array of equally spaced points, produced by the intersection of fine parallel lines (maximum width 0.3 mm), and shall have 16 or 25 points. It is recommended that the spacing of the points should be 10 mm along both directions parallel to the edges of the square grid, e.g. as in Figure. D2.1. At a magnification of x 1000 this corresponds to a point spacing on the actual microstructure of 10 m.

7. Procedure

Superimpose the test grid on the magnified image of the microstructure in the chosen area of the parent material or weldment.

Count the number of points which lie within the delta ferrite phase; any points which cannot be assigned positively to either phase shall be counted as one half. Delta ferrite is the phase which is stained dark by the etch, although its colour may vary significantly throughout the weldment. The austenite phase remains light coloured in all areas after etching.

The test piece shall then be moved by a small amount in x and/or y so that another field is chosen. A second point count shall be performed in the new field, provided that this field of view still falls within the specified region of the parent material or weldment. If the field of view falls outside the area of interest the specimen shall be moved back, without rotating, to an appropriate position within the specified area. Where possible the test piece should be moved without looking at the micro-structure in order to avoid bias in the choice of fields. It is recommended that the use of overlapping fields be avoided. This process shall be continued until a minimum of 400 points have been counted.

When measurements are being made within the coarse grained HAZ, the operator shall first assess whether the test grid can be superimposed over an area which is entirely within the coarse grained HAZ. This can be done simply by attempting to fit the grid within a single coarse grain. If the grid size is less than the grain size, then the technique described above shall be used. If the whole grid is too large, a smaller area of the grid shall be used, by ignoring one or more whole rows of grid points. The area chosen may be either square or rectangular. If a rectangular grid is used, the specimen shall be rotated so that the long axis of the rectangle is kept parallel to the fusion boundary.

Measurements in the coarse grained HAZ shall be made within 0.2 mm of the fusion line.

The volume fraction, as defined by ASTM E 562, of delta ferrite shall be estimated by taking an average of the point fractions counted in each of the n fields as follows:

(equation 1)

May 2005 Page 45 SP-1097


where (i) is the field number.

The 95% confidence interval (CI), as defined by ASTM E562, shall be calculated as follows:

(equation 2)

where

(equation 3)

The accuracy of the technique shall comply with the allowable errors specified in Table D2.1 where the error is as defined in ASTM E 562.

8. Reporting

The following details shall be included in the point counting report:

i. The number of sections taken from the weld.ii. The locations of sections taken along the weld.iii. The polishing procedure and etching conditions.iv. The magnification used.v. The number of points and shape of the grid.vi. Whether the fields were chosen randomly or at regular intervals. If regular intervals

were employed, report the spacings used.vii. The location of the areas in which measurements were made, preferably on sketch

or photograph and in words, specifying parent metal or the weld pass, the region of the weld pass (i.e. weld metal or HAZ) and, where practical, whether the area was re-heated or not. Any uncertainty should be indicated.

viii. A list of the point fractions of delta ferrite in each field.ix. An estimate of the volume fraction of delta ferrite, calculated as the average of the

point fractions.x. The calculated value of the 95% CI.xi. Stage of manufacture, i.e. procedure qualification, production test, etc.xii. Location of sample and heat number.xiii. Statement of conformance with specified ferrite content.xiv. Signature of operator responsible for ferrite determination.

SP-1097 Page 46 May 2005


Figure D2.1 Two grid types suitable for systematic manual point counting of delta ferrite in duplex stainless steel

+ + + + +

+ + + + +

+ + + + +

+ + + + +

+ + + + +

Table D2.1 Allowable error in ferrite/austenite determination

Volume % Error

45-50

40-45

35-40

0-35

± 10%

± 11%

± 12%

± 14%

May 2005 Page 47 SP-1097


Appendix E Certificate of Compliance

DECLARATION/CERTIFICATE OF COMPLIANCE FOR PIPELINE FABRICATION AND INSTALLATION

Description of pipeline

Identification no./Drawing No.

Installed by:

For

Design conditions:

Design temperature:

Medium contained:

Designed by:

We hereby declare that above pipeline has been fabricated, installed, examined and tested in accordance with this SP-1097

Company:

Signature

(Name, position, date)Project QA/QC In-charge

Specimen of declaration/certificate of compliance for pipeline fabrication and installation

SP-1097 Page 48 May 2005


User Comment Form

User Comment Form If you find something that is incorrect, ambiguous or could be better in this document, write your comments and suggestions on this form. Send the form to the Document Control Section (DCS). They make a record of your comment and send the form to the correct CFDH. The form has spaces for your personal details. This lets DCS or the CFDH ask you about your comments and tell you about the decision.

Procedure Details Title: Issue Date:Number:

Page Number: Heading Number: Figure Number:

Comments:

Suggestions:

User’s personal detailsName: Ref.

Ind.:Signature: Date:

Phone:

Document Control Section ActionsCommentNumber:

Date: CFDHRef. Ind.:

Recd.: To CFDH:CFDH ActionsRecd.

Date:

Decision:

Reject:Accept, revise at next issue:Accept, issue temporary amendment

Inits.: Ref.Ind.:

Date:

Comments:

OriginatorAdvised:

Date: Inits.: Document ControlSection Advised:

Date: Inits.:

May 2005 Page 49 SP-1097

specification for welding of duplex stainless steel pipelines amendmentssupplements to api std 1104

Documents

welding of test repair

sampling of test fillet

branch welds

sampling of test butt

testing of repair welds

radiography butt welds

test methods

specification requirements