Welding of Duplex Stainless Steel Pipelines

8/18/2019 Welding of Duplex Stainless Steel Pipelines

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Version 2.0 Specification for Welding of Duplex Stainless Steel Piping

Contents

1. Introduction ..................................................... ........................................................... ......... 1 1.1 Purpose................................................................ ......................................................... .... 1 1.2 Changes to the Specification................ ...................................................................... ...... 1 1.3 Effective Period .............................................................. ................................................. 1

1.4 Review and Improvement........................................................... ..................................... 1 1.5 Process Owner's Responsibility ............................................................. .......................... 1

2. Specification for Welding Duplex Stainless Steel.............................................................. 2 2.1 Specification Requirements ........................................................ ..................................... 2 2.2 Process Deliverables ........................................................... ............................................. 2 2.3 Performance Levels / Indicators ............................................................ .......................... 2 2.4 Performance Monitoring ............................................................ ...................................... 2

Appendix A Glossary of Definitions, Terms and Abbreviations........... ............................... 3

Appendix B Amendments/Supplements to ASME B31.3 ..................................................... 6

Chapter V Fabrication, Assembly and Erection ................................................................. .. 6

328 Welding ....................................................... ................................................................ .... 6 328.2 Welding Qualifications...................................................................... ................... 6

328.2.1 Qualification Requirements............................................................................. 6 328.2.1.1 General......................................... ........................................................ 6 328.2.1.2 Welding Procedure Specification ........................................................ 6 328.2.1.3 Essential Variables......................................... ...................................... 7 328.2.1.4 Test Welding................ ................................................................ ........ 8 328.2.1.5 Examination of the Test Weld ........................................................... 10 328.2.1.6 Destructive Testing of the Test Weld ................................................ 10 328.2.1.7 Retests.................................................................. .............................. 13 328.2.1.8 Approval of the WPS..................... .................................................... 13 328.2.1.9 Performance Qualification ................................................................. 13

328.2.2 Procedure Qualification by Others...... .......................................................... 14 328.2.3 Performance Qualification by Others............................................................ 14 328.2.4 Qualification Records............................................................................. ....... 14

328.3 Welding Materials ................................................................ .............................. 15 328.3.1 Filller Metal...................................................... ............................................. 15

328.3.1.1 Storage and Handling of Filler Metals and Fluxes ............................ 15 328.3.1.2 Shielding Gases......................................................................... ......... 16

328.3.2 Weld Backing Material .................................................................. ............... 16 328.3.3 Consumable Inserts .............................................................. ......................... 16

328.4

Preparation for Welding ............................................................ ......................... 16 328.4.1 Cleaning ......................................................... ............................................... 16

328.4.2 End Preparation......................... ........................................................... ......... 16 328.4.3 Alignment................................................................... ................................... 17

328.5 Welding Requirements ........................................................... ............................ 18 328.5.1 General.................................................... ...................................................... 18 328.5.2 Fillet and Socket Welds ........................................................ ........................ 20 328.5.4 Welded Branch Connections..................... .................................................... 21

328.6 Weld Repair ......................................................... ............................................... 21 328.6.1 General.................................................... ...................................................... 21 328.6.2 Welding of Test Repair Welds...................................................................... 22 328.6.3 Testing of Repair Welds ................................................................ ............... 22

330 Preheating.............................................................. ....................................................... 22 330.1 General.......................................................... ...................................................... 22

December 2004 SP-1096 ii


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Specification for Welding of Duplex Stainless Steel Piping Version 2.0

330.1.1 Requirements and Recommendations............................................................22 330.1.

330

330.2.4 Interrupted Welding ........................................................ .............................. 23

331 Heat Treatment ........................................................ .................................................... 23

332 di

332.1 General................................................................................................................23

333 Brazing and Soldering..................................................................................................23

336 ndl

336.3 Pipe Handling......................................................................................................24

Chapter VI Inspection, Examination and Testing............................................................... 25

340 pec

340.4 Qualifications of the Owner’s Inspector ............. Error! Bookmark not defined.

341 m

341

.3.

341

341.4.1 Examination Normally Required...................................................................25

342 m

342.1 Personnel Qualification and Certification ........................................................... 26

343 Examination Procedures..............................................................................................26

344 es

344

.2.

344

.5.

344.6 Ultrasonic Examination.......................................................................................28

345 tin345.1 Required Leak Test ......................................................... .................................... 28

346 or

346.1 Documentation............................................................ ........................................ 28

4 Preheat Zone..................................................................................................22 .2 Specific Requirements ................................................................ ........................23

Ben ng and Forming ..................................................................................................23

Ha ing and Storage ..................................................................................................23 336.1 General................................................................................................................23 336.2 Storage .................................................... ............................................................ 24

Ins tion.......................................................................... Error! Bookmark not defined.

Exa ination..................................................................................................................25 341.2 Responsibility for Examination...........................................................................25

.3 Examination Requirements .................................................................... .............25 341.3.1 General ........................................................ .................................................. 25 341 2 Acceptance Criteria ................................................................ ....................... 25 .4 Extent of Required Examination.........................................................................25

Exa ination Personnel ................................................................................................26

Typ of Examination ..................................................................................................27 .2 Visual Examination.............................................................................................27 344 2 Method...........................................................................................................27

344.3 Magnetic Particle Examination .............................................................. .............27 344.4 Liquid Penetrant Examination.............................................................................27

.5 Radiographic Examination..................................................................................27 344 3 Method...........................................................................................................27

Tes g ...........................................................................................................................28

Rec ds..........................................................................................................................28

iii


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347 Certificate of Conformity ........................................................ .................................... 29

Table 1 Extent of Non-Destructive Testing for Welds ........................................................ 30

Figure 1 Hardness Indent Locations .................................................................. ............ 32

Figure 2 Orientation and Location of Charpy Impact Specimens .............................. 33

Appendix C References.............................................................................. ............................ 34

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

Systematic Point Count ......................................................... ............................................ 36

Appendix E Certificate of Compliance.............. ................................................................ ... 40

User Comment Form ....................................................... ....................................................... 41

iv


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1. Introduction

1.1 Purpose

This specification is a revision of SP-1096 version 1.0, Specification for Welding of Duplex

Stainless Steel Piping, issued in July 1999. The purpose of this document is to define theminimum technical requirements for the welding of duplex stainless steel (DSS) pipework.

This specification is intended to be used where the applicable code has been designated by

the Company as ASME B31.3, 2002. Chemical Plant and Petroleum Company Piping,

(normally on-plot locations).

This document is not applicable to the welding of DSS pipelines, where the applicable code

has been designated as ASME B31.4 or ASME B31.8 (off-plot locations) or to the

manufacture of welded DSS pipe

1.2 Changes to the Specification

This Specification shall not be changed without approval from the Custodian, the Material

and Corrosion Functional Discipline Head (CFDH) who owns this Specification. If youthink 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.

1.3 Effective Period

The requirements of this specification shall remain in force indefinitely unless superseded by

an authorised revision.

1.4 Review and Improvement

This specification will be reviewed and updated once every three years. The review authoritywill be CFDH Materials and Corrosion.

1.5 Process Owner's Responsibility

The owner of this specification is 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 1.4.

Page 1


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2. Specification for Welding Duplex Stainless Steel

This specification gives the minimum requirements for the welding, fabrication and

inspection of duplex stainless steel on-plot pipework. The scope is intended to cover all

commercially available compositions (MESC), including 22Cr and 25Cr duplex/superduplex

grades. The specification is restricted to piping for service in non-sour environments where

the applicable Code for pressure piping is designated by the Company as ASME B31.3,

Chemical Plant and Petroleum Refinery Piping. The use of duplex stainless materials in

environments containing H2S shall be subject to approval by the Company.

2.1 Specification Requirements

Welding, fabrication and inspection shall be in accordance with the requirements of ASME

B31.3, 2002 Edition, as amended and supplemented by Appendix B of this specification.

The amendments and supplements given in Appendix B are considered necessary to ensure

integrity of the fabricated pipework in accordance with PDO and Shell Group requirements.

The Clause numbering in Appendix B follows that of ASME B31.3. Where clauses of

ASME B31.3 are not amended or supplemented by Appendix B, they shall apply in their entirety.

2.2 Process Deliverables

Process deliverables comprise shop or field welded duplex stainless steel pipework and

related welded fabrications designed to ASME B31.3 and normally intended for on-plot oil,

gas or water service.

2.3 Performance Levels / Indicators

See relevant ASME B31.3 weld inspection and testing acceptance criteria and the

amendments given in Appendix B of this specification.

2.4 Performance Monitoring

Requirements for monitoring welding process variables, welder performance and weld

quality are detailed in relevant sections of ASME B31.3/ASME IX as amended by Appendix

B of this specification.

December 2004 Page 2 SP-1096


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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 ASME B31.3.

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/ The party ch manufactures or supplies equipment and

Company etroleum Developmant Oman LLC. The Company will

y may

User he Company, Consultant or Contractor who uses this

Corporate Functional he person within the Company responsible for the discipline to

shall dicates a requirement. Any deviation to a requirement shall be

should dicates a recommendation. A deviation to a recommendation

may dicates a possible course of action.

Specific Definitions

Batch or Lot

8.3.1)

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

Duplex Stainless Steel chromium-nickel-molybdenum stainless steel containing a

Nominal Thickness ominal thickness t shall have the following meanings:

butt joint; parent metal thickness, which for joints between

etween

pe.

Owner erm used in ASME B31.3 that shall be understood to mean

Supplier

whi

services to perform the duties specified by the Contractor.

P

generally specify the technical requirements. The Compan

also include an agent or consultant authorised to act for, and on

behalf of, the Company.

T

document.

Discipline Head

T

which the standard belongs.

In

approved by the CFDH.

In

shall be approved by the welding (TA-2).

In

(see App. B, 32 Clause 6 (Testing)

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.

N

-

dissimilar thicknesses is that of the thinner material.

- fillet weld; parent metal thickness, which for joints b

dissimilar thicknesses is that of the thicker material.

- set-on branch connection; thickness of branch pipe

- set-through branch connection; thickness of main pi

T

the Company.



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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 EuropeanWelding 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

ASNT American Society for Non-destructive Testing

CFDH Corporate Functional Discipline Head

AWS American Welding Society

CSWIP Certification Scheme for Welding Inspection Personnel

D Nominal Outside Diameter

DSS Duplex Stainless Steel

DNV Det Norske Veritas

GTAW Gas Tungsten Arc Welding

IQI Image Quality Indicator

HAZ Heat Affected Zone

HV Vickers Hardness

NDE Non-destructive Examination

PAMS Portable arc monitoring system

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



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T Nominal Thickness

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

TWI The Welding Institute

WPS Welding Procedure Specification

WFS Wire Feed Speed



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Appendix B Amendments/Supplements to ASME B31.3

Chapter V Fabrication, Assembly and Erection

328 Welding

Delete introductory paragraph and replace as follows:

Welding shall be performed in accordance with the requirements of ASME B31.3 and the

amendments and additions of this specification. The work shall be undertaken only by

Contractors that have been approved by the Company specifically for the on-plot welding of

duplex stainless steel, (Work Category CE6421). Approval of Contractors shall be based on

Company document GU-225.

The welding Contractor shall maintain and operate a quality system that shall be in

accordance with ISO 9001:2000, and SP-1171. A quality system based on alternative

standards to of ISO 9001 may be considered for agreement by the Company. All welding

and related activities shall satisfy the requirements of ISO 3834-2. It is recommended tofollow the guidelines given in PD CR 13576.

328.2 Welding Qualifications

328.2.1 Qualification Requirements

Delete entire section and replace as follows:

328.2.1.1 General

Where the Contractor is unable to provide satisfactory records to demonstrate the suitability

of the proposed welding procedure specification and compliance with ASME B31.3 and this

specification, welding procedure qualification shall be undertaken prior to the

commencement of production welding.

The Contractor shall submit WPS proposals to the Company for review and approval a

minimum of two weeks prior to undertaking qualification welding. The WPS proposals

shall be endorsed by the Contractor's Welding Engineer. A Welding Procedure Register

shall accompany the package. This shall list and identify all WPS/PQRs intended to be used

for the contract, detailing as a tabulated summary welding processes, materials and qualified

dimensional ranges.

The qualification of dissimilar welds, between duplex stainless steel and other material

groups, shall be in general accordance with this specification, except that welding

consumables and specific test requirements will be agreed by the Company Welding TA - 2(or higher) for each application.

Note: 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.

328.2.1.2 Welding Procedure Specification

The format of the WPS shall be equivalent to form E00006, shown as QW-482 in Appendix

A of ASME IX, and shall contain the following applicable parameters, including

explanatory details where necessary.

• Material specification of base metals.



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• Welding process and whether manual or automatic.

• Wall thickness and diameter range for which the procedure is valid, (see 328.2.1.3 (c)and (d)).

• Geometry of the welding groove showing allowable tolerances.

• Root gap showing allowable tolerances.

• Welding position and direction.

• Filler metal specification and diameter.

• Filler metal classification and coating type.

• Specification of flux.

• Tungsten electrode type and specification.

• Gas shielding flow and composition.

• Gas backing flow and composition

• Number of weld passes for which gas backing is required.

• Number and sequence of all passes, indicating stringer or weave beads. For automaticwelding the weave amplitude, weave frequency and dwell time shall also be included.

• Welding current range, voltage range and polarity. If pulse welding is used, the background current and range of pulse parameters or unique program reference to be

included.

• Where applicable, electrode stick-out and WFS range.• Travel speed range for each pass.

• Heat input range.

• Preheat and interpass temperatures.

• Methods of joint preparation interpass cleaning and weld finishing.

• Method of clamping/tacking, including details of removal

Test welding shall not commence until the WPS proposal has been stamped 'Approved for

Qualification' with the date and the contract number, and signed by a Company welding

TA-2.

328.2.1.3 Essential Variables

When changes in any of the parameters listed below are made beyond the indicated limits,

the welding procedure shall be set up as a new WPS and shall be completely re-qualified.

(a) Welding process A change to another welding process or a change from

manual to automatic operation or vice versa.

(b) Base materials Any change in UNS number. A change in the PREN

exceeding –1.5 or +2.5. 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..

(c) Thickness For t > 5mm, a change in thickness at the joint outside

the range 0.75t to 1.5t, but not < 5mm. For t < 5mm,a

change outside the range t to 1.5t. For a fillet weld, in

addition to material thickness, a change in throat

thickness outside the range 0.75a to 1.5a.

(See Appendix A of this specification for definitions of

t).

(d) Diameter (D) Change in pipe or branch diameter outside the

following ranges:

D


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(e) Joint design Any change in joint configuration outside the specified

tolerance.

(f) Welding position Any change, except that, subject to the approval of the

Company Welding TA-2, qualification of a joint in the

fixed 45° inclined (6G) position shall qualify for all

positions.

(g) Welding

progression

A change from uphill to downhill or vice versa.

(h) Filler

metal/electrode

Any change in electrode/filler metal classification or

trade name, except that for solid filler wire, a change to

a different trade name may be accepted without re-

qualification subject to the approval of the Company

Welding TA-2. Any change in electrode or filler wire

diameter.

(i) Flux Any change in size, classification or trade name.

(j) Shielding or backinggas

A change in nominal flow rate of more than ±20%.Any change in nominal composition of shielding or

backing gas. Any increase in maximum oxygen

content of effluent backing gas.

(k) Number and

sequence of passes

Any change in the sequence of filling or capping passes

beyond that required to accommodate the qualified

range of joint dimensions. Any decrease in the number

of passes before cessation of backing gas.

(l) Electrical

characteristics

A change of more than ±15% in the individual values

for volts, amps and wire feed speed determined from

the PQR. Changes in individual parameters and ofwelding speed, (clause (m)), shall be controlled such

that heat input is maintained within the permitted range

of clause (n).

A change of electrode polarity or current type,

including the addition or deletion of pulsating current.

(m) Speed of travel Any change greater than ±15%.

(n) Heat input Any change in average welding heat input per pass

outside the range ±10% of that qualified.

(o) Preheat or interpass

temperature

An increase of more than 50°C in the specified

minimum preheat temperatures or any increase in

maximum interpass temperature.

(p) Post-weld heat

treatment

The inclusion or deletion of PWHT or any change in

PWHT parameters.

328.2.1.4 Test Welding

Sufficient test welds shall be made to extract all the destructive test specimens required for

qualification testing. Test welding shall be witnessed by the Company Welding TA-3. The

Contractor shall give the Company a minimum of 48 hours notice of the intention to proceed

with test welding.



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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 .

Prior to the commencement of test welding, the Contractor shall have available at the test

site the following documents for verification by the Company:

• Original copy of the WPS proposal, endorsed ‘Approved for Qualification’

• Material certificates or verified copies, traceable to the items to be welded.

• Batch certificates or verified copies, traceable to the welding consumables, (see

328.3.1).

• Approved consumable handling procedure.

Test welding shall not commence until the Company has reviewed and accepted the

documentation. All test welding shall be witnessed by a Company representative having a

Welding Technical Authority level 3 or higher. The Contractor’s Welding Coordinator who

is approved by the Company shall supervise the entire welding procedure qualification

process. The Contractor shall be responsible for examination and shall have a Company

approved welding examiner (Welding Inspector) present throughout test welding and NDE

of the welds. NDE shall be performed only by Company registered NDE subcontractors in

accordance with SP-1176.

The test weld shall simulate as closely as possible the actual production environment and

welding set-up used, including as applicable, clamping, support and back purging

arrangements. 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.

The following information shall be recorded for each pass of the test weld and shall form

part of the PQR:

• Pass number

• Welding process

• Consumable diameter

• Consumable trade name and classification (including flux for SAW)

• Electrode polarity

• Gas composition

• Gas flow rate

• Arc voltage

• Current

• Wire feed speed

• Travel speed

• Preheat temperature

• Interpass temperature

• Pass sequence

The test weld information shall be recorded on welding parameter sheets which shall be

attached to the completed form E00007, shown as QW-483 in Appendix A of ASME IX.

Pass sequence shall be shown in the sketch on the ASME form. The Approved for

Qualification WPS, original or verified copies of the test coupon material and consumable

batch test certificates and the original PAMS unit printout shall be included as part of the

PQR. The welding records of the test welding shall be signed, dated, and endorsed by the

Contractor's welding examiner (Welding Inspector) and the Company welding TA-3 presentat the time of test welding.



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If post weld heat treatment is required, a heat treatment record chart shall be produced and

shall be endorsed by the Contractor, the heat treatment sub-contractor (if applicable), and the

Company Welding TA-3 present during heat treatment. The chart shall be included in the

PQR.

328.2.1.5 Examination of the Test Weld

NDE shall be witnessed by a Company Welding TA-3 (or higher) or by a Third Party

Inspector nominated by the Company.

The NDE shall consist of the following:

• Visual examination

• Liquid penetrant testing

• Radiographic testing

NDE 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. NDE

of a test weld may serve as a qualification test for the NDE procedures.

The acceptance criteria shall be as stated in Chapter VI of ASME B31.3 and the

corresponding sections 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.

The radiographic report shall be signed by the technician and the Contractor's welding

examiner prior to presenting the radiographs to the Company Welding TA-3 with

interpretation qualification for viewing. After viewing, the Company Welding TA-3 shall

sign and endorse the radiographic report and it shall be incorporated into the PQR.

328.2.1.6 Destructive Testing of the Test Weld

Testing for procedure qualification shall be performed in accordance with ASME IX and the

additional requirements in Paragraphs (a) to (f), following. 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 the controlling specifications. The Company shall

have the option 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. The test reports shall be included in the

PQR.

(a) Macro-examination

Two macro-sections shall be taken from a butt weld in pipe at the 12-1 o'clock and the6-7 o'clock positions. Where two welders have made the joint, the macro specimens

shall be taken from the specified positions such that each welder's portion is sampled.

For branch welds, four macro-sections shall be taken at 90° intervals through the centre

of the joint, in line with the longitudinal or transverse axis of the run pipe.

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 performed to confirm the microstructure of the

weld/HAZ and the absence of deleterious phases. Observations shall be included with

the macroscopic examination report

Macro-examination shall be carried out at a minimum magnification of x5. The

acceptance criteria shall be as detailed in chapter VI of ASME B31.3 and shall include



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measurements for height of reinforcement and internal protrusion. Following the

hardness measurements detailed below in paragraph 328.2.1.6(b), macrophotographs

shall be produced for inclusion in the PQR.

(b) Hardness survey

For pipe, a hardness survey shall be performed on each macrosection. The hardness,shall be measured in accordance with ASTM E92 using a 10 Kg load. For pipe butt

welds, the hardness indentations shall be as shown in Figure 1 of this specification and

shall be clearly visible in the macrophotographs. For pipe of t less than 10 millimetres,

the mid-thickness traverse may be omitted. One indent of each HAZ set of three shall

be as close to the fusion line as possible but shall not intercept it.

The sections of the weld taken for macroscopic examination and hardness testing shall

also be used for the ferrite measurements required in the following clause, 328.2.1.6(c).

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

(c) Ferrite measurement

The ferrite content shall be determined by microscopic point counting in accordance

with ASTM E562 and Appendix D of this specification, For DSS, a magnetic

measurement technique using an instrument calibrated to AWS 4.2 may be used.

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 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, acheck 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.

(d) Charpy V-notch impact tests

Each procedure qualification shall include impact testing unless the nominal pipe wall

thickness is less than 4.8 mm. The sampling area of the weld shall be as shown in

Figure QW-463.1(f) of ASME IX.

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 2 of this specification.



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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.

Testing in accordance with ASTM A370 and this specification shall be conducted at

minus 20°C 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

10 x 7.5 30 23

10 x 5 20 15

(e) Corrosion testing

A pitting corrosion resistance test shall be conducted in accordance with ASTM G48,

Method A, using the total immersion ferric chloride test. A coupon specimen of

dimensions 5 cm x 5 cm x full wall thickness shall be prepared to the requirements of

ASTM G48, Section 5. No flattening of the coupon material shall be carried out. Theweld 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. Other

surfaces shall be in the "as-finished" condition.

The specimen shall be degreased, dried, 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 22°C ± 2°C. For the higher alloyed 25Cr duplex/superduplex

grades the test temperature shall be 35-37ºC unless otherwise specified

On completion of the test period the specimen shall be rinsed, cleaned, dried andreweighed 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

expressed as total weight loss and weight loss per unit area. The latter shall not exceed

8g/m2.

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

(f) 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 328.3.1) shall be determined. The PRE value shall exceed the minimum

specified for the base material to be welded.



16/44


328.2.1.7 Retests

With the exception of Charpy tests and hardness tests, if any one mechanical test specimen

fails to meet the minimum requirements, two additional test specimens shall be extracted and

tested. The Contractor shall notify the Company of the test failure and obtain written

Company approval to proceed with retests. If both of the retests are acceptable that

particular test shall be deemed as acceptable. Should one or both of the retests fail then the procedure shall be rejected immediately.

For hardness tests, if only one hardness result exceeds the specified maximum then a

minimum of three further indentations 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 maximum

specified hardness the test shall be accepted. The Contractor shall notify the Company of the

test failure and obtain written Company approval to proceed with retests

For Charpy 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.

Retesting of any corrosion 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.

If the test joint fails to meet the minimum requirements, a new WPS proposal shall be

established and qualification welding and testing repeated.

328.2.1.8 Approval of the WPS

Subsequent to successful non-destructive and destructive testing, the Contractor shall submitthe original PQR showing endorsement and signatures of the Contractor, the testing

subcontractor, and the Company. The Contractor shall also submit a copy of the WPS to be

used for production welding and, if necessary, a revised welding procedure register for

review and approval by a Company Welding TA level 2 or higher.

Production welding shall not commence until the WPS has been endorsed 'Approved for

Fabrication' with the date and the contract number, and signed by a Company welding

Technical Authority level 2. Only those WPSs shown on the approved WPS register shall

be used in production.

328.2.1.9 Performance Qualification

Welders and welding operators shall be qualified in accordance with the requirements of

ASME IX and of this specification.

For Super DSS any change which necessitates requalification of the WPS shall also require

requalification of the welder. For DSS, the following essential variables shall be applied for

welder qualification:

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

pipe diameter.

(c) A major change in joint configuration, e.g. ‘U’ to ‘V’ preparation(d) A change in welding progression from uphill to downhill or vice versa.(e) For manual welding electrodes, a change from one coating type to another

(f) Any change in the nominal composition of the shielding gas.



17/44


Welders shall have a valid Company qualification within the validity defined in this

specification or they shall be qualified on contract materials using a WPS endorsed

‘Approved For Fabrication’. A calibrated portable arc monitor shall be used to record

welding parameters. 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 theCompany Welding TA-2. The Company reserve the right to disqualify any welder whose

performance during production welding is not satisfactory.

The Company shall be given a minimum of 48 hours notice of intention to perform welder

qualification in order to witness the test welding. Welding and testing shall be witnessed by

a Company Welding TA-3. Butt weld test pieces shall be subjected to visual examination,

radiography, bend testing and macroscopic examination to the requirements of ASME IX,

QW-302 and this specification.

A welder who fails to meet the acceptance criteria shall be allowed an immediate retest. A

welder who fails to meet the acceptance criteria after the first retest shall not be allowed a

second retest within seven days. The Contractor shall demonstrate that the welder has

undergone training in that period. Failure to demonstrate training shall prevent the welder

from being retested. Should the second retest fail then that welder shall be disqualified for

the duration of the contract.

Performance qualification data shall be recorded by the Contractor on ASME form E00008

(QW-484) or other format agreed by the Company. The ASME form shall then be endorsed

and signed by the Contractor and the Company Welding TA-3 who witnessed the test

welding. The completed record forms shall be submitted to the Company Welding TA-3

who shall issue a welder's card which shall show the WPS for which the welder is qualified,

the welder's unique identification, and the Company TA-3 signature and endorsement. The

welder shall maintain the card in his possession at the job site and shall produce it upon

request by the Company. Failure to produce the card shall prevent the welder from welding

until such time as it is produced. The card shall be the property of the Company and shall berevocable by the Company.

The Contractor shall assign an identifying number, letter, or symbol to the qualified welder

which shall be used to ensure traceability to specific welds. If a welder ceases to work for

the Contractor, the unique identification shall not be reassigned to another welder.

328.2.2 Procedure Qualification by Others

Delete section and replace as follows:

Procedure qualification by others, as defined in ASME B31.3 shall not be permitted.

328.2.3 Performance Qualification by Others


Performance qualifications made for another employer shall not be accepted.

328.2.4 Qualification Records


See sections 328.2.1.2, 328.2.1.4 and 346.1 of this specification.



18/44


328.3 Welding Materials

328.3.1 Filller Metal

Add the following, including new sub-sections 328.3.1.1 and 328.3.1.2:

Only consumables from Company approved suppliers shall be used. Approval shall includethe manufacturing plant and shall be verified by a third party inspection agency.

Each batch of consumables shall be tested in accordance with the AWS procedures specified

for the consumable classification. The tests shall be conducted with third party witness and

verification at a Company approved facility. Batch testing is required, irrespective of

whether the consumables are supplied with a verified copy of the Supplier’s/Manufacturer's

batch certificate. 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.

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 thoseof the filler used in the corresponding procedure qualification test.

• The PRE of the filler metal, as calculated from the batch test certification on the basisdefined below, should be at least 2 units higher than the minimum specified PRE of 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.

328.3.1.1 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 manufacturer's instructions. Consumables shall remain in their original containers which

shall be marked with the manufacturer's name, the consumable trade name, and the 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 should be maintained

at a maximum relative humidity of 50%, which shall be monitored in accordance with an

agreed procedure.

Consumables delivered in containers that exhibit physical damage, shall be examined for

damage. Consumables that show signs of damage or deterioration 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 the 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 datasheets for the flux

prior to its arrival at site. Flux shall remain identifiable and traceable. Recycling shall not

be permitted.

Wherever available, basic coated electrodes should be supplied in sealed vacuum packs

having a guaranteed hydrogen content. Electrodes not supplied in such 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 150°C after baking,from where they shall be issued to heated quivers maintained at a minimum temperature of



19/44


70°C. Duplex stainless steel electrodes shall not be stored in the same heated cabinets a

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 identi

the contents and their location in the baking and holding ovens. Oven internal storage

arrange

s

fy

ments shall not allow intermixing of different electrodes (manufacturers and/or

sizes).

r

e

one re-bake. The Contractor shall have a system for identification of re-baked electrodes.

e

e consumable

handling procedure has been approved by the Company Welding TA - 2.

328.3.1.2 Shielding Gases

ed on the WPS and shall be the same for procedure qualification and

production welding.

Gases in containers that are unidentifiable shall not be used.

328.3.2 Weld Backing Material

Delete existing section and replace as follows:

Backing rings shall not be used.

328.3.3 Consumable Inserts


Consumable inserts shall not be used.

328.4 Preparation for Welding

328.4.1 Cleaning


all be

ing, the end preparation shall

be degreased with a non-chlorinated solvent such as acetone.

328.4.2 End Preparation

(a) General

Delete existing clause (1) and replace as follows:

Consumable control shall be such that any basic coated electrodes shall be used within fou

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 th

baking oven. Electrodes shall be baked a maximum of two times, i.e. one initial bake and

Prior to the commencement of qualification or production welding, whichever is sooner, th

Contractor shall submit a consumable handling procedure to the Company for review and

approval. Test welding or production welding shall not commence until th

The shielding and purge gas shall be certified as complying with ISO 14175, AWS 5.32 or

equivalent. Hydrogen shall not be added. The purity or component concentrations of the

gas shall be as specifi

Fusion faces and the surrounding surfaces within a minimum of 25 mm of the joint sh

free from heavy scale, moisture, oil, paint, or any other substance which may have a

deleterious effect on the weld quality or progress. Before weld



20/44


(1) Bevels shall normally be machined or prepared by grinding. Preparation of weld

edges by plasma cutting is permissible provided a mechanically guided torch is

used. Prepared edges shall meet the cleanliness requirements of clause 328.4.1 of

this specification. Equipment/consumables used for grinding and cleaning of edge

preparations shall be dedicated for stainless steel work and identified by colour

coding or other suitable means. Wire brushes shall be of stainless steel.

Add the following new clauses (3) to (5):

(3) The cut surface shall be ground to a smooth, bright uniform finish by removing

approximately 0.5 mm of metal. After grinding, the weld edges and surrounding

material shall be cleaned and visually examined to ensure freedom from cracks,

notches or other defects which may affect weld quality. Any bevelled edge that has

been damaged shall be restored by machining or grinding within the tolerances

required by the welding procedure to be applied. Restoration involving welding

shall not be permitted.

(4) All preparations in pipe of 273 mm OD and above and/or wall thickness of 12.7

mm and above and all cut-backs made to rectify defective end preparation,

irrespective of pipe size, shall be inspected as follows:

• The pipe shall be ultrasonically examined for laminations over a zone of 50mm back from the new bevel edge. The acceptance criteria shall be that the

maximum dimension of the minor axis of the lamination shall not exceed 6.3

mm and the maximum product of the major and minor axes shall not exceed 50

mm2.

• The new bevel shall be liquid penetrant examined and shall be free fromrelevant linear indications.

• All examinations shall be in accordance with Company approved procedures.

(5) Prior to a cut-out for a branch connection, a zone 50 mm wide around the outside

diameter of the proposed hole shall be utrasonically checked for laminations. Thecompleted bevel shall be liquid penetrant examined. The procedures and

acceptance criteria shall be those specified for cut-backs in the preceding

paragraph.

(b) Circumferential welds

Delete existing clause (4) and replace as follows:

(4) The deposition of weld metal to rectify internal misalignment shall not be

328.4.3 Alignm

ntial welds

se (1):

a maximum of 1 mm provided it is distributed equally

around the circumference. If the misalignment exceeds the above value, provided it

Add

permitted.

ent

(a) Circumfere

Add the following to clau

Misalignment is permitted to

is caused by dimensional variations within the specified tolerance or the use of two

piping components of different nominal thickness and the same out side diameter,

trimming at the internal diameter of the thicker member to a taper of 1:4 may be

carried out. Wherever possible, such rectification should be carried out by

machining in a shop rather than by grinding in the field.

the following new clause, (3):



21/44


(3) Line-up clamps shall be employed where possible. These shall have stainless steel

inserts or shall be clad with a suitable material to prevent contact between the

duplex stainless steel pipe and carbon steel. Stainless steel spacing tools shall be

used in conjunction with the line-up clamp to ensure proper joint spacing. 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.

Add the following new sub-section (e):

(e) Weld separation

The toes of adjacent circumferential welds shall be separated by a minimum distance

equal to the nominal outside diameter of the pipe. Where the above requirement cannot

be met, the minimum distance between the toes of adjacent circumferential welds shall

not be less than five times the nominal wall thickness or 50 mm whichever is greater.

And both joints shall be subjected to RT and PT checks.

When circumferential welds are to be made in pipe of welded manufacture, the

longitudinal welds shall be so positioned that:

• the weld is at the upper segment of 120° of the pipe line

• any two adjacent longitudinal welds shall be at least 45° apart.

328.5 Welding Requirements

328.5.1 General

The material certificates shall be verified and approved by the contractor Quality Assurance

Engineer and made available for review to the Company before the commencement of

welding / fabrication.

(a) WPS

Add the following:

All welding shall be in accordance with the ‘Approved for Fabrication’ WPS.

(b) Weld identification

Delete the last sentence and replace as follows:

The Contractor shall maintain records of the weld number and the welder identification

for each weld for inclusion in the document package. The production records shall also

include the results of monitoring and verification of the welding parameters (volts,

amps, travel speed and heat input) representing one pass per WPS, per welder, per day(excluding the capping runs) unless agreed otherwise with Company Welding TA-2

authority. A calibrated portable arc monitor shall be used to record welding parameters.

(c) Tack welding

Delete existing sub-section and replace as follows:

Root tack welding shall not be permitted. Where tack welding is necessary, only bridge

or bar tacks may be used. These shall be welded using the electrodes and parameters

shown in the approved WPS for the fill passes. Welding shall not encroach on the root

area. The bridge or bar material shall match the composition of the parent material.

The tack welds shall be removed by grinding as welding progresses around the joint.

(d) Weld Finishing



22/44



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 the 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 ofspatter, burrs, and other imperfections that could interfere with radiographic or

ultrasonic inspection.

(e) Weather protection


Work shall not be performed when the weather and/or degree of protection does not

permit satisfactory workmanship.

For site welding, shelters giving adequate protection at all times to the weld area from

wind, rain and moisture shall be provided. In windy conditions the pipe ends shall be

sealed to prevent through draughts

Weld surfaces shall be thoroughly cleaned and dried before welding. Moisture shall be

removed by means of blowers, or in exceptional cases a torch may be used in

accordance with Section 330.1.1 of this specification.

Add new sub-sections, (g) to (k):

(g) Application of welding processes

(1) Gas Tungsten Arc Welding (GTAW)

Manual or automatic GTAW with filler metal addition shall be used for the root andsecond pass of all single sided butt welds. These processes may also be used for

filling and capping passes. Automatic GTAW may be used in uphill and downhill

progression. The manual GTAW process shall be restricted to uphill progression.

U-groove preparation without root gap should be used for automatic welding.

The tungsten electrode shall be AWS class EWTh-2 or EWCe-2. The GTAW

power source shall have a high frequency starting circuit, slope-out control and gas

delay facility as a minimum.

Argon, Helium or Argon/Helium mixtures of at least 99.99% purity shall be used as

shielding and backing gas. The use of argon containing an addition of up to 2%

nitrogen is also permissible. Hydrogen additions are not permitted.

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.

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.

(2) Submerged Arc Welding (SAW)



23/44


SAW shall be used only for filling and capping in the flat position with the pipe

rotated. Wire and flux shall be from the same manufacturer.

(3) Shielded Metal Arc Welding (SMAW)

The SMAW process shall be used only for filling and capping and only in the

positions recommended by the consumable manufacturer. Welding shall not be performed in the downhill direction.

(4) Other welding processes

Welding shall normally be restricted to the processes listed in (1) to (3) above.

Proposals to use other processes may be submitted to the Company Welding TA-2

for consideration in exceptional cases.

(h) Arc strikes

Arc strikes shall be ground out to a smooth profile. The ground area shall be examined

by liquid penetrant examination and thickness checked. The area shall be free from

cracks. Where the thickness is below the specified minimum that 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 of current return cables shall be made directly

to the work using clamps having stainless steel contact surfaces.

(i) Inter-run cleaning

Each run of weld metal shall be cleaned before a further run is deposited. Visible

defects such as cracks, cavities, and other deposition faults shall be removed by

grinding prior to deposition of further weld metal.

(j) Temporary attachments

Temporary attachments shall not be used.

(k) Transition joints between dissimilar metals

The Contractor shall consult with the Company and agree the WPS and qualification

requirements.

328.5.2 Fillet and Socket Welds

From 1st sentence, delete”(including socket welds)”.

Add to sub-section (a), the following::

Socket welding shall not be permitted.

Delete existing sub-section (b) and replace as follows

(b) Where the use of slip-on flanges is agreed by the Company, attachment shall be by

continuous double fillet welds.

Add following new sub-section:



24/44


(c)

tails

may be supported by appropriate butt weld qualifications. Otherwise separate

h ASME IX and this specification shall be required.

328.5.4 s

A

(i) hall be prepared for each type of branch weld detail. Separate

qualification of branch welds shall be carried out in accordance with ASME B31.3 and

n.

328.6

ion and replace as follows:

328.6.1

All repairs shall be executed by welders qualified in accordance with ASME B31.3 and this

l be

g TA-2. The

WPS shall be qualified using simulated repairs to an appropriate test weld, except that

a by this specification, the WPS shall show the following:

• The method of excavation

e total length of excavation shall

not exceed 30% of the weld length. For full penetration repairs, the total length of

Each type of repair shall be separately qualified, including full penetration, partial

f the

excavation there shall be a gradual taper from the base of the excavation to the surface of the

e

original weld. Surfaces shall be thoroughly cleaned before depositing

further weld metal. Back welding to repair a root mismatch (Hi-Lo) is only permissible if

d for the original weld to a length extending 50 mm beyond each end of the

repair. Should further unacceptable defects be found on re-inspection then the weld shall be

A specific WPS shall be prepared for each fillet weld attachment detail. Subject to

review and acceptance by the Company Welding TA-2, qualification of these de

qualification in accordance wit

Welded Branch Connection

dd following new sub-section:

A specific WPS s

this specificatio

Weld Repair

Delete entire sect

General

specification. The Contractor shall maintain records of repair work.

Repair welding procedures shall be prepared and qualified for each type of repair to be

performed in accordance with Section 328.2 of this specification. A separate WPS shal

produced for repair welding and shall be approved by the Company Weldin

repairs to fillet welds may be qualified by a suitable butt weld repair PQR.

In ddition to the items required

• The NDE technique employed to ensure removal of defects

Cracks shall not be repaired. When cracking is observed in the completed weld, the weld

shall be cut out entirely. For partial penetration repairs, th

excavation shall not exceed 20% of the weld length.

penetration and cap welds.

Excavation shall be by machining or grinding. After excavation, visual and liquid penetrant

inspection shall be performed to confirm defect removal. At the ends and the sides o

weld metal. The profile shall be such that adequate access for welding is achieved.

Undersize welds shall be rectified by the deposition of additional weld metal, using the sam

procedures as for the

covered by a PQR.

After completion of repair welding, the full extent of the repair shall be inspected by the

method prescribe

cut out entirely.



25/44


328.6.2

The initial butt weld shall be welded to the appropriate qualified WPS. The maximum depth

of

s been agreed, separate qualification shall be made. Generally, test

repair weld excavations should be centred at the fusion line so as to include weld metal and

shall be shown on the WPS and agreed by the Company.

for

ing.

328.6.3

d procedure is representative of the original weld qualification, the

ructive tests shall be performed on butt weld repairs, (cap repairs should be

cedure qualification tests shall apply. Destructive

-

- ferrite measurements, which shall include measurements made in the new HAZ formed in

, where appropriate, shall include samples notched in the new HAZ

e original weld.

ing, to include the junction of new and original weld metal

330 Preheating

330.1 General

330.1.1

Preheat will not normally be required by the WPS. If welding is likely to be performed

mited

preheat may also be applied in highly constrained conditions provided that this does not

es

ern nozzles. Welding or cutting torches shall not be used.

rpass temperature shall be 150oC, unless a lower value is specified on the

approved WPS. Temperature measurement shall be by thermocouple, thermomelt crayon,

ermomelt crayons shall not be applied

within the bevel area.

330.1.4

The heated area shall extend for a minimum of 75mm either side of the joint and shall be

maintained over the full length of the joint until the weld is completed. A period of

Welding of Test Repair Welds

of partial penetration repair welds shall the lesser of 0.5t or t-6 mm. Where the execution

single run repairs ha

parent material. The location

Each repair shall be of sufficient length to provide the specified number of specimens

destructive test

Testing of Repair Welds

Non-destructive testing of the repair test weld shall be performed as specified for the

original weld.

Provided the repair wel

following dest

tested as fillet welds). Otherwise, full pro

testing shall be in accordance with the methods and acceptance criteria of Section 328.2.6:

- 1 transverse tensile

bend test

- 1 macroexamination and hardness test

the original weld.

- Charpy testing which

formed in th

- corrosion test

Requirements and Recommendations


below 15°C or condensation of moisture on the weld area is possible, a minimum preheat of

50°C shall be applied to a bandwidth of at least 75mm either side of the joint. A li

contravene the essential variables of the qualified WPS, (see 328.2.1.3(p)).

Acceptable methods of pre-heating are electrical resistance heaters or oxy-propane torch

fitted with rosebud patt

The maximum inte

contact pyrometer or a combination of these. Th

Preheat Zone




26/44


equalisation shall be allowed, based on two minutes per 25mm thickness, prior to

confirmation that the specified temperature has been attained.

330.2 Specific Requirements

330.2.4 Interrupted Welding

Interruption of welding should be avoided. Where interruption is unavoidable, a minimum

he joint thickness, whichever is greater, shall have been

331 Heat Treatment

fied only in exceptional circumstances. Individual

agreed with the Company as necessary.

332 Bending and Forming

Delete existing section entirely and replace as follows:

332.1

all

nds or any other

shop forming operations becomes necessary, this shall be restricted to cold working

ontamination of the work by carbon steel.

t procedures shall be approved by the Company prior

333 oldering

elete the existing section entirely. Brazing and soldering processes are outside the scope

of this specification.

336 Handling and Storage

336.1

osure

,

ds beads and for

preventing oxidation during welding, are included in Sections 328.4, 328.5.1 and 332.1 of


of three passes or one third of t

deposited.


Post weld heat treatment will be speci

requirements and procedures shall be

General

Field bending of duplex stainless steel pipework shall not be permitted. Maximum use sh

be made of factory produced components. Where shop fabrication of be

techniques. Contact faces of forming equipment shall be of stainless steel or lined with

suitable material to prevent c

Detailed fabrication and heat treatmen

to commencement of work.

Brazing and S

D

Add the following new section:

General

All necessary precautions shall be taken throughout fabrication to minimise contamination

of duplex stainless steel materials resulting from direct contact with carbon steels, exp

to ferrous dust, swarf or other debris and from residual deposits on or near fusion faces

during welding. Specific requirements to prevent contamination during edge preparation

joint alignment or site fabrication, for cleaning fusion faces and wel

this specification. General precautions to be applied during the handling and storage ofduplex stainless steels are outlined in clauses 336.2 - 3, following.



27/44


Surface oxidation or metallic contamination that does 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

shing shall be performed with potable water.

336.2

nmental contamination.

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

336.3

ge or contamination of the duplex pipework.

blies shall be of

Nylon or similar compatible material.(c) Pipe handling by means of hooks in pipe ends shall not be permitted.

pipework. Wa

Storage

(a) Components stored in an open site or within a fabrication workshop shall be protected

from enviro

materials.

Pipe Handling

(a) Supports, rollers and other pipe handling equipment shall be of compatible material or

shall be suitably lined to prevent dama

(b) Slings and supports for lifting duplex stainless steel pipe and assem



28/44


Chapter VI Inspection, Examination and Testing

341 Examination

341.2 Responsibility for Examination

Add the following new sub-sections (d) and (e):

(d) The Contractor shall supply all labour, materials, and equipment necessary to perform

the required examinations.

(e) The Company shall have the final disposition on any weld. Those welds not accepted

by the Company shall be rectified in accordance with ASME B31.3 and this

specification.

341.3 Examination Requirements

341.3.1 General

Insert the following in front of the first paragraph:

Before commencing production, the Contractor shall examine free-issue materials for

all

the

341.3.2 Acceptance Criteria


The acceptance criteria shall be as stated in ASME B31.3 and this specification.

Limits on imperfections shall be assessed in accordance with Table 341.3.2 with the

nated

341.4 Extent of Required Examination

341.4.1 Examination Normally Required

(a) Visual Examination

Delete all clauses of existing sub-section and replace as follows:

Visual examination prior to welding shall be in accordance with the provisions of

(b) Other examination

Delete all clauses of existing sub-section and replace as follows:

The extent of examination for all butt welds shall be in accordance with Table 1.

Ultrasonic examination may supplement radiography and shall be used to interpret

damage and compliance with the relevant materials specification. This examination sh

include a review of the materials certificates. Items supplied without materials certificates

shall not be used. All damage and discrepancies shall be reported immediately to the

Company. After signed acceptance by the Contractor, any discovered damage shall be

responsibility of the Contractor.

exception that Incomplete Penetration shall not be permitted, (symbol ‘A’ to be desig

for girth/mitre groove welds and branch connections).

sections 328.4 and 341.3 of ASME B31.3 and this specification. All completed welds

shall be visually examined. 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.



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doubtful indications in the radiographs. Fillet welds shall be subjected to visual, and

liquid penetrant examination at the same frequency as radiography for butt welds per

fluid service and class.

Branch connection welds shall be radiographically examined where possible. Where

radiography is not possible, ultrasonic examination shall be employed. Where

ll inform the Company of cases where neither radiography nor

ultrasonic examination can be performed and obtain written Company approval for

pecified, the Contractor shall ensure that

a minimum of 2% of the welds made by each welder is included in the overall

shall not substitute for the specified NDE.

342 Ex

rtification

id qualification of one of the following listed

below and should have previous experience of duplex stainless steel welding or have

• AWS CWI with 10 years experience

pany as equivalent to the above.

the method of

NDE to be carried out in accordance with ISO 9712. The roles and responsibilities of NDE

Level

y, welding examination or non-destructive examination

personnel fail to perform to a satisfactory standard they shall be disqualified from the works

343 es

specified examination shall be prepared bythe Contractor and submitted for Company approval (by an Inspection TA-2) a minimum of

ultrasonic examination is not possible, liquid penetrant examination shall be performedon the final weld.

The Contractor sha

liquid penetrant examination to be used alone.

When random non-destructive examination is s

percentage examined.

In-process examination

amination Personnel

342.1 Personnel Qualification and Ce


Welding examination personnel shall hold a val

received a period of specialised training satisfactory to the Company welding TA-2.

Acceptable qualifications for welding examiners are as follows:

• CSWIP 3.1 with 10 years experience

• Other qualification agreed by the Com

Non-destructive examination personnel shall be qualified and certificated for

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 NDE 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

II and shall take corrective measures whenever the performance of ASNT Level II

technicians is not satisfactory.

If, in the opinion of the Compan

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.

Examination Procedur


Written NDE procedures covering each type of



30/44


two weeks prior to test or production welding as applicable. The procedures shall be projec

specific and shall show the project name and contract number. Company approval shall be

based on qualification tests, which may be conducted as part of the Welding Procedure

Qualification testing. The procedures shall incorporate the requirements of SP-1176.

Types of Examination

t

344

ing section and replace as follows:

ance with a documented procedure

complying with Article 9 of ASME BPV Code Section V. The examiner shall maintain and

hapter

rior to examination.

344.3

344.4 nt Examination

s:

in accordance with a documented

procedure complying with Article 6 of ASME BPV Code Section V and incorporating the

ll be as stated in Chapter VI of ASME B31.3 and this

specification. The technician and the Contractor's Welding Co-ordinator shall sign and

he

344.5

ing section and replace as follows:

accordance with a documented procedure

complying with Article 2 of ASME BPV Code Section V and incorporating the

iography shall be by X-ray. Gamma radiography shall not be

used for wall thicknesses less than 10mm. Where the use of X-radiography is agreed by the

used for radiography performed to this

specification. Sensitivity shall be 2% or better. IQIs shall be wire type, of stainless steel orequivalent.

344.2 Visual Examination

344.2.2 Method

Delete exist

Visual examination shall be

Documents

Welding of Duplex Stainless Steel Pipelines