general welding fabrication and testing

8/22/2019 General Welding Fabrication and Testing

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Standard

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Rev.: 0

Page: 1 of 24

Date:07/06/09GENERAL WELDING, FABRICATION AND INSPECTION

TABLE OF CONTENTS PAGE

I. SCOPE 2

II. REFERENCES 2

III. WELDING PROCEDURES 3

IV. WELDING PROCESSES (GENERAL) 4

V. WELDING PROCESS LIMITATIONS 5

VI. FILLER MATERIALS AND FLUXES 6

VII. WELD JOINT PREPARATION AND WELDING FABRICATION 9

VIII. PREHEAT AND INTERPASS TEMPERATURES 13

IX. POSTWELD HEAT TREATMENT 14

X. NON-DESTRUCTIVE EXAMINATION, TESTING AND INSPECTION 17

XI. REPAIRS 20

XII. SUMMARY OF WELDING VARIABLE LIMITATIONS, 21RESTRICTIONS AND OTHER REQUIREMENTS

XIII. PROCEDURE FOR REVIEW AND ACCEPTANCE OF

VENDOR WELDING PROCEDURES 22

APPENDIX I - WELD MAP 24


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GENERAL WELDING, FABRICATION AND INSPECTION

I. SCOPE

A. This Standard covers the minimum welding requirements, for welding of shopand field fabrications and the weld inspection of the following:

1. Pressure containing equipment and piping, whether code stamped or not,

including but not limited to: rotating equipment, boilers, pressure vessels,

heat exchangers, air coolers, shop and field fabricated piping, fired heatertubes, storage tanks, stacks and their attachments.

2. Equipment or piping containing toxic or corrosive materials.

3. Structural Steel

4. Other fabrications where specified.

B. This Standard modifies the requirements of applicable ASME, AWS, API and

ANSI codes and standards in effect at the revision date.

C. Conflicts between requirements of this Standard, related specifications, standards,

codes, purchase orders or drawings shall be clarified with Client or Client'sEngineer (designated Contractor) prior to proceeding with the fabrication of the

affected parts. Regarding conflicts, the Client reserves the right of final decision.

D. Where conflicts exist between this Engineering Standard and other POLARISEngineering Standards and/or applicable codes or regulations, the more stringent

requirement shall govern. All conflicts shall be brought to the Clients attentionfor resolution. The Client shall be the sole arbiter of any conflicts.

II. REFERENCES

This POLARIS Standard is to be used in conjunction with the latest revision of the

standards and codes listed below, unless specifically noted. The terminology "latest

revision" shall be interpreted as the revision in effect at the time of contract award. ThisPOLARIS Standard may reference specific sections of some of these codes and

standards. The revision of the codes and standards being referenced is noted below inparenthesis. This information is provided to identify the subject matter being referenced.Changes or exceptions made to the referenced code or standard shall apply to later

revisions as applicable.

A. POLARIS Engineering Standards


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3. 840.1 General Requirements For Pipe Fabrication

B. National Codes and Standards

1. API American Petroleum Institute Standards

2. AWS American Welding Society Standards

3. ASME B16.5 Pipe Flanges and Fittings (1998)

4. ASME B31.1 Power Piping (2001)

5. ASME B31.3 Process Piping (2001)

6. National Board Inspection Code (NBIC)7. ASME Boiler and Pressure Vessel Code (2001)

III. WELDING PROCEDURES

A. Welding procedure specifications (WPS) and procedure qualification test records(PQR) for Vendor welding covered by this Standard shall be submitted to the

Client or the Client's Engineer for review and acceptance prior to the start of any

welding. No welding shall commence until welding procedure specifications and

qualification records have been accepted by Client or Clients representative.

B. Welding performed by Subvendors is also required to go through the same reviewand acceptance procedures described in III.A above. Vendors are required to

provide copies of this and all other relevant standards to their Subvendors and to

review their Subvendors welding procedures for conformance to this Standard

prior to submitting to the Client or Client's Engineer for acceptance.

C. The information contained in the welding procedure specifications and procedure

qualification test records shall include, but not be limited to the informationcontained in ASME Code, Section IX and AWS D1.1. Welding procedure

specifications shall conform to ASME Section IX, Form QW-482 or equivalent.Procedure qualification records shall conform to ASME Section IX, Form QW-483 or equivalent. Structural steel welding procedures may conform to AWS

Prequalified or AWS Recommended Procedure formats.


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D. This Standard includes additional requirements and restrictions, which may not be

listed in the Vendor's submitted welding procedures. They shall be listed, when

required by this Standard, either in the welding procedure or on the weld map.The main additional requirements are summarized in Section XII below.

E. Vendor shall prepare a Weld Map Form" as illustrated in Appendix I of thisStandard which must be completed and submitted at the same time as welding

procedures for Client's acceptance. Vendor may submit this information in other

formats provided all information required in Appendix I is included.

F. All welders shall be qualified by means of welding performance testing. Welding

performance qualification test records shall be made available for review by the

Client or Client's Representative upon request. Welding performance tests shallbe in accordance with ASME Section IX or AWS D1.1 as applicable, under

conditions of restraint and accessibility as demanding as those to be experienced

in production by the welder. Welding performance test records shall conform toASME Section IX, Form QW-484 or equivalent. Welding performance testing

records for structural steel shall conform to the recommended AWS format.

G. Weld overlay or clad back-welding shall be qualified in accordance with ASMESection IX.

H. Weld overlaying or clad restoring (back-cladding) shall be applied with aminimum of two passes and capable of controlling dilution as evidenced by a

chemical analysis. Depth of chemical analysis shall be three-quarters of the

required overlay thickness unless specified otherwise and approved by Client.

I. When impact testing is required by the code or POLARIS Standards, impact test

results for weld and heat affected zone shall be reported with the weldingprocedure qualifications.

J. When maximum Brinell hardness is specified by code, POLARIS Engineering

Standards, or Section X.D.8 of this Standard, they shall be reported with thewelding procedure qualification record and they shall not exceed the maximum

specified limits.

IV. WELDING PROCESSES (GENERAL)

A. The following welding processes are permitted, subject to the limitations set forthin Section V below, providing that satisfactory evidence is submitted showing that

the procedures qualified are in accordance with applicable codes, standards, andthis Standard.

1. Manual shielded metal arc with covered electrode (SMAW)

2. Gas tungsten arc: manual or automatic (GTAW)


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3. Automatic or machine submerged arc (SAW)

4. Oxy acetylene cutting (OFC-A)

5. Gas metal arc (GMAW)

6. Flux Core Arc Welding (FCAW)7. Plasma Arc Welding (PAW); manual, automatic or machine

B. Welding processes other than those listed above require specific approval by the

Client or Client's Engineer and shall not be assumed as acceptable by the Vendor

during bid preparation.

C. Fabricators and welders shall be capable of demonstrating satisfactory experience

with the selected acceptable welding processes listed in this standard. First timeuse of a welding process requires specific written approval by Client prior to

welding.

D. Client and Client's Engineer reserve the right to disallow the use of any weldingprocess or welder based on excessive rates of repair.

V. WELDING PROCESS LIMITATIONS

A. GMAW and FCAW processes shall have stated in the WPS, and on the required

weld map (see Appendix I), whether the current is in the short circuiting arc or

spray transfer range. The shop and the welding personnel shall havedemonstrated production welding experience with each process to the satisfaction

of the Client and Client's Engineer.

B. GMAW is acceptable for root passes and completion of welds up to 3/8 inch

deposited weld metal thickness for groove welds and 3/8 fillet weld size. When

specific Client permission is obtained to exceed this maximum depositedthickness; all such welds shall be 100% ultrasonically shear-wave examined

throughout their entire length.

C. FCAW, in the short circuiting arc mode, is unacceptable.

D. FCAW, spray transfer, without shielding gas, is acceptable with specific Clientapproval for structural steel welding fabrication only.

E. FCAW, spray transfer, with shielding gas is acceptable for welding shop

fabricated pipe and for welding pressure retaining parts of pressure vessels

provided the following conditions are met:

1. The procedure qualification record shall include results of micro hardness

testing for both as-welded and stress relieved conditions as applicable for


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weld, heat affected zone, and base.

2. Production NDE shall include 100% hardness testing on all FCAWweldments per Section X, Paragraph C.

F. GMAW and FCAW for field fabrication must have the Client's specific approval.

G. Automatic or machine type SAW is preferred. The SAW process shall have

stated on the WPS that the procedure is automatic or machine type welding in

order to be acceptable. Manual or semi-automatic SAW is prohibited.

H. Automatic or machine type SAW of P-1 materials shall be limited to 1/2 inch

maximum thickness per layer of deposit for material of 1-1/4 inch thickness orgreater and 3/8 inch maximum thickness per layer of deposit for material less than

1-1/4 inch thick. The maximum deposit for alloy and stainless steel shall be

limited to 0.4 inches per pass.

I. GTAW shall be utilized for pipe fabrication on first two layers for ferrous alloy,

and non-ferrous alloys on single welded groove joints accessible for one side only

and on other equipment as defined in the POLARIS Engineering Standards.GTAW shall be used on all piping buttwelds on P-1 materials 2 NPS and

smaller.

VI. FILLER MATERIALS AND FLUXES

A. Filler materials and fluxes shall be as specified in ASME, Section II, Part C.,

Filler Materials and Fluxes, other than those specified in the above code andwhich meet other requirements of this Standard, shall not be assumed as

acceptable by the Vendor during bid preparation.

B. All welding shall employ a filler metal unless approved by the Client in writing.

Welding employing no filler metal shall not be assumed as acceptable by the

Vendor during bid preparation. Friction welding is prohibited.

C. The specific AWS grade, ASME specifications, Manufacturer and trade name for

filler metals and fluxes to be used on the project shall be indicated on the weldingprocedure specification and weld map (Appendix I).

D. Use of filler metals and fluxes for other than the Manufacturer's primaryrecommended application is prohibited. For example: Filler wire intended for

OFW shall not be used for GTAW. Filler wire intended for certain weldingpositions specified by the Manufacturer shall not be utilized in other welding

positions. Fluxes recommended for single pass shall not be utilized on multi-pass

welds.

E. Automatic or machine submerged arc welding fluxes are subject to the following

limitations:


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1. Fluxes used for welding carbon or low alloy steels shall not contributealloying elements to the weld.

2. The use of Lincoln 780 flux is prohibited.3. A separate welding procedure qualification shall be required for each

brand and grade of flux and electrode combination.

4. Welding procedures employing "active" fluxes for carbon steel shalldemonstrate that hardness does not exceed 200 BHN. Hardness shall be

reported with the procedure qualification record.

5. Alloy steel shall be welded using an alloy wire and a "neutral" flux. Fluxes

shall not contribute alloying elements to the weld deposit.

F. Fluxes shall be reconditioned prior to re-use in accordance with Manufacturer's

recommendations. The use of re-crushed slag is prohibited.

G. Carbon steels of group P-1 shall be welded with A-1 analysis weld metal only.Use of other weld metal analysis numbers requires the Client's approval.

H. For welding 70 KSI tensile strength P-1 material subject to a PWHT, filler metalscontaining 1/2% Mo are permitted in order to meet the minimum tensile strength

requirement.

I. Similar base materials shall be joined with a weld metal deposit that matches thebase metal in both chemistry and mechanical properties. In cases where this

cannot be accomplished, the Vendor shall propose a choice of filler together withthe reasons for the choice for the Client's review and approval.

J. Welds joining pressure containing parts of two different ferric steels shall have a

weld metal deposit conforming to the nominal composition of the higher alloybase materials unless otherwise approved by the Client.

K. Welds joining two different ferric steels, only one of which is a pressure retainingpart, shall have a weld metal deposit conforming to the nominal composition of

the pressure retaining part unless the engineering design specifies otherwise andwritten approval is given by the Client.

L. When joining two different austenitic stainless steels, the (A-8) filler metal maymatch either and must result in a ferrite number range of 3-12. Delta ferrite shall

be determined from the certified chemical analysis and the "WRC Delta Ferrite

Diagram."

M. Welds joining austenitic stainless steels to ferritic steels shall be made with filler

metal as follows:


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1. Type 309 for design temperatures not exceeding 650oF.

2. Coated electrodes of SFA 5.11 AWS classes ENiCrFe-2 (comparable to

Huntington Alloy's INCO A) and ENiCrFe-3 (comparable to HuntingtonAlloy's INCO 182) or bare electrodes of SFA 5.14 of AWS ClassesERNiCrFe-5 (comparable to Huntington Alloy's INCO 62) and ERNiCr-3

(comparable to Huntington Alloy's INCO 82) except where process

conditions do not permit.

3. TP 310 fillers are acceptable only for welding of Type 310 base materials

to themselves.

N. For GMAW and GTAW welding of P-1 materials exceeding 65 KSI minimum

tensile strength, only AWS classification ER70-S2 or ER70-S3, filler metals of

SFA 5.18 shall be used. The use of ER70-SG & GS, ER-70C-G & GS of SFA5.18 is prohibited without prior submittal and approval of the filler metal material

test reports (MTRs) for each lot. Their utilization shall not be assumed as

acceptable by the Vendor during bid preparation. When use of this material is

approved by Client the material shall be marked and segregated for the job.

O. For FCAW of carbon steels exceeding 65 KSI minimum tensile strength, only

AWS Classification E7X-T1 or E7X-T5 filler metals of SFA 5.20 shall be used.

P. Use of SMAW electrode groups F-1, F-2, and F-3 as specified in ASME Section

IX, Table QW-432, are limited as follows:

1. To fillet welds or butt welds on material not exceeding 65 KSI minimum

tensile strength, in material thickness not exceeding 1/2 inch thickness.

2. F-1, F-2, and F-3 electrodes are not permitted on materials requiring

impact tests.

3. F-1 or F-2 electrodes shall not be used for pressure retaining parts or non-

pressure attachments to pressure retaining parts.

4. F-3 electrodes may be used for root passes of butt welds regardless of base

metal thickness.

Q. The receipt, use, dispersal and retrieval of welding filler materials shall be

maintained under strict control, with storage, baking and drying as recommendedby the Manufacturer to assure that completed welds conform to the approved

welding procedure specification requirements for welding materials.


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VII. WELD JOINT PREPARATION AND WELDING FABRICATION

A. Joint designs shall be in accordance with applicable code or POLARISEngineering Standard requirements.

B. Weld joints shall be prepared by machining, grinding or thermal cutting. Whenthermal cutting is performed, the joint surfaces shall be ground to sound metal

prior to welding. Materials shall be subjected to the same preheat requirements

for thermal cutting as required by the applicable welding procedure.

C. For austenitic material 2 inches and thicker, plate edges, including weld bevels

shall be liquid penetrated tested.

D. Welded butt joints shall meet the minimum requirements for penetration or fusion

in accordance with the applicable code or POLARIS Engineering Standard

requirements.

E. The addition of permanent backing such as rings, bars, or strips are unacceptableand shall not be used without the Client's written approval. Their utilization shall

not be assumed as acceptable by the Vendor during bid preparation. Theadditional backing referenced in this Standard is not defined by this Standard as

the weld installed on the first side of a butt weld welded from both sides.

F. Temporary (removable) backing rings, bars, or strips shall not be used without the

Client's written approval. Their utilization shall not be assumed as acceptable by

the Vendor during bid preparation.

G. If approved by the Client, the weld area exposed when backing is removed shall

be dressed and examined for cracks or defects by visual and liquid penetrated ormagnetic particle examination methods, whichever is applicable. All backing

material and unacceptable indications shall be removed completely and repaired

utilizing a weld procedure which has been accepted by the Client.

H. Materials of temporary backing rings, if approved by the Client, shall conform to

the nominal chemistry of the weld filler metal as defined in Section VI of this

Standard.

I. When Client's approval is given for use of backing rings, the Vendor weldingprocedure and the weld map (Appendix I) submitted for review shall eitherindicate that welding was qualified with backing ring (state on PQR) or that

backing ring will be added (stated on WPS and the weld map, Appendix I).

J. Consumable inserts require written approval by the Client. Their utilization shall

not be assumed as acceptable by the Vendor during bid preparation. If approvedby Client, they shall in all cases conform to the nominal chemistry of the weld

filler metal as defined in Section VI of this Standard. In all cases, they shall

require root shielding with inert gas.


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K. The materials used for pipe purging dams and methods employed in their

placement, use, and subsequent removal shall be as required to ensure that nodamage results to the piping or related components.

L. The method that is proposed by the Vendor to obtain and maintain adequate rootshielding shall be included either as part of the submitted welding procedure or as

a separate standard for review. The procedure for root shielding by inert gas shall

contain the following:

1. The composition and purity of shielding gas to be used.

2. Flow rates and time required to obtain adequate purging.

3. Pipe dam details materials to be used, type of construction, method of

placement and removal.

M. Unless otherwise specified, back-purging (root shielding), when required, shall be

maintained until completion of 2 weld layers.

N. Weld joint tolerances for root opening and alignment shall meet the requirements

of applicable codes and POLARIS Engineering Standards, and also the weld joint

sketches contained in the submitted welding procedures to ensure against lack ofpenetration and lack of fusion.

O. For shop and field fabrication, when poorly fitted joints occur with excessive joint

gap or excessive offset, the Vendor shall submit a separate weld repair procedureindicating with a sketch the method proposed to bring the joint back to original

design requirements in conformance as close as possible to the original Clientaccepted welding procedure. The Vendor cannot assume that backing rings or

strips, permanent or temporary, are acceptable without the Client's review. Any

weld joints of this nature found to be slugged with supplementary filler metal are

unacceptable. The weld build up of beveled ends to close excessive gap isunacceptable unless a Vendor welding procedure is submitted for doing so and is

accepted by the Client.

P. Grinding and cleaning of stainless steels and nonferrous material shall be done

only with tools that will not leave detrimental deposits on the base metal;aluminum oxide or silicone carbide grinding wheels and austenitic stainless steelwire brushes shall be used. These tools shall not have been previously used on

other than the material to be cleaned.

Q. Surfaces to be welded shall be clean and free of paint, oil, dirt, scale and other

foreign materials, which may contain lead, sulfur, and other low melting pointelements detrimental to welding. Beveled edges are to be cleaned and coated with

deoxaluminate paint prior to shipment. Preparation of the bevel just prior to

welding shall be as specified on the applicable welding procedure specification.


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R. Penning of welds to enhance mechanical properties is prohibited.

S. Tack welds which are to be incorporated into the final weld shall be subject to all

the same requirements as the applicable welding procedure, including preheat,and are to be performed by welders qualified to perform the welding procedureaccepted for that joint. If separate tackers are used other than the welder

performing the joint weld, they shall be qualified for performance on all the same

welding variables for the portion of the weld they perform as stated in the

applicable accepted welding procedure or else the tack welds shall be completelyremoved.

T. Tack welds shall be made with filler metal of the same composition as will beused for the first pass of the weld as stated in the applicable accepted welding

procedure for the joint.

U. All slag shall be thoroughly removed from tack welds and the leading and trailing

edges shall be blend ground to a feather edge prior to welding the root pass or

covering pass.

V. Tack welds that violate any of the above requirements shall be completely

removed. Completed welds having tack welds found to violate any of the above

shall be subject to complete removal.

W. Removable start-up and run-off tabs shall be used for longitudinal welds.

Materials used for these tabs shall be of the same composition as the base weld.

X. For alloy clad plate and material, the following limitations shall apply for

preparation at the joint prior to back-cladding:

1. Cladding shall be stripped back to a minimum of 1/4 inch from the edge of

base material bevels by machining, grinding or arc gouging.

2. Removal of the cladding shall not reduce the base material thickness

below the design thickness.

3. A minimum radius of 1/16 inches shall be used at the limit of cladding

removal unless the clad material is beveled at least 30o

.

4. Preparation of local repair cavities in overlay welds that penetrate into the

base material more than 10% of its thickness, or 3/16 inch, whichever isless, shall have the base material rewelded with the appropriate Client

accepted welding procedure consistent with the base material prior to

completing the overlay repair.

5. Copper sulfate test to ensure complete cladding removal.


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Y. Strip type lining shall be attached to the shell circumferentially and shall be

designed so that the distance between attachment welds does not exceed that

shown below. The weld between the strips shall be at least 1/4 inch and not morethan 1/2 inch in width. Strip lining shall be a multi-pass fillet-butt weld of three

(3) weld minimum design with 100% dye penetrant testing of final weld. SeeFigure A below.

Figure A

Strip Welding Linings

Vessel Operating Temperature Distance Between Welds

650 F and Under 4 inches

Over 650oF Not permitted (See VII.Z)

Z. Vessels with integrally clad type linings shall be made of explosion bonded plate

or plate clad with the required lining material in the steel mill in accordance with

the mills standards. These standards are to be approved by Client.

AA. Weld overlays shall consist of at least two layers so that the required depth of the

top layer will have the alloy composition required for the service. The first layer

may be made with electrodes of higher alloy content to compensate for dilutioneffects. The finished surface shall be 100% examined by the liquid penetrant

method of examination.

BB. All stubs, rods, flux, slag or foreign material shall be removed from the equipment

or piping after completion of welding and prior to postweld heat treatment or

hydrostatic test.

CC. The use of temporary welded attachments shall be avoided where possible. Alllocations of removed temporary attachments shall be examined visually after

removal of the attachment.

1. Temporary attachments shall be removed by flame cutting, arc gouging or

grinding. Hammering off is not permitted. (This paragraph does notapply to atmospheric storage tanks within the scope of Standard 1115.1

and API 650.)

2. Defects discovered in the base metal such as gouges, cracks or undercuts


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shall be removed and repaired and the area re-examined using the same

method of NDT that revealed the original defect.

DD. Vertical welding shall be performed vertical up. Downhill welding is not

permitted except for the GMAW root pass only.

EE. For field erection of API storage tanks, the weld seams of sketch plates for tank

bottoms and floating roofs shall contain a minimum of two weld passes. Single

pass seams are not acceptable.

FF. Branch Connections

1. Branch connections such as weldolets, threadolets, sockolets, and stub-insshall be joined to the header by full penetration welds. Incomplete

penetration as defined by Table 341.3.2, Note B of ASME B31.3, is not

acceptable.

2. Start and stop welds on root pass shall be feathered in.

3. Branch connections shall be prepared in accordance with Figure 328.4.4(A), (B) or (C) of ASME B31.3. A minimum root gap of 1/16 inches shall

be maintained during welding. The root gap shall be stated in the welding

procedure specification.

VIII. PREHEAT AND INTERPASS TEMPERATURES

A. Preheat shall be at least sufficient to dry surfaces to be welded but not less than50

oF. Higher temperatures may be required for highly restrained joints such as

closely spaced nozzles. Carbon steel plates 1.25 inch thick or more, shall bepreheated to 200

oF minimum and ferritic alloy plates to 300

oF minimum prior to

flame cutting and ground smooth prior to welding. All such prepared edges

including holes cut for nozzles or manways, shall be liquid penetrant examined or

magnetic particle inspected for cracks or laminations.

B. Minimum preheat temperatures shall not be less than that stated in ASME,

Section VIII, Division 1, Appendix R and Paragraph UCS 56; ASME B31.1,Paragraph 131; or ASME B31.3, Table 330.1.1, as applicable. Minimum preheat

temperatures are required to be stated on the welding procedure specification.

C. Preheat maintenance shall be applied when required by the Client for the

conditions stated below. Preheat maintenance is the maintenance of the statedminimum preheat temperature, without interruption, from start to completion of

welding. Vendor must either state on the WPS or weld map that preheat is to be

maintained when so required by Section VIII of this Standard. Loss of preheatmaintenance will require complete liquid penetrant or magnetic particle

inspection of the uncompleted seam prior to any further welding. Any defects

found must be reported to the Client's Inspector for his review.


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D. Preheat maintenance is required for the following:

1. Equipment and piping, regardless of service or wall thickness, of the P-5B,

C, and D material groups (where chrome content exceeds 4%) and of P-6and P-7 materials.

2. Modifications to existing equipment and piping, regardless of material orwall thickness in hydrogen service. Hydrogen service is defined as: Any

service in which the partial pressure of hydrogen in the fluid handled is 50psia or more. This work requires a hydrogen bake-out, pre-heat

maintenance and PWHT.

3. Pressure vessel and exchanger seams, nozzle and attachment welds of P-1,P-3, P-4 and P-5 group materials, regardless of service, if shell or head

thickness is equal to or greater than 1-1/2 inch.

4. Piping fabrication, regardless of material or service, if thickness is equal to

or greater than 3/4 inch.

E. The same preheat requirements shall be met as are required on the Client accepted

welding procedures for thermal cutting, gouging, tack welding and welding

repairs.

F. The maximum preheat and interpass temperature for P-8 materials shall be 350oF.

The maximum preheat and interpass temperature shall be specified on the WPS

for all materials of material group P-7 and higher.

IX. POSTWELD HEAT TREATMENT

A. Postweld heat treatment (PWHT) shall be performed in accordance with the

ASME Code and/or POLARIS Engineering Standard 840.4, as applicable. The

applicable code or Standard for PWHT shall be referenced on the weld map(Appendix I). The maximum and minimum holding temperature and holding time

shall also be stated on the WPS. POLARIS requires a two (2) hour minimum

holding time for all equipment and piping to be heat treated.

1. For all equipment, except field fabricated tanks and piping, the post weldheat treatment procedure outlined in the ASME Code, Section VIII,Paragraphs UW-40, UW-49, and UCS-56, shall be followed. The

exemptions provided for in the notes to Table UCS-56 are permitted withClient approval.

2. Complete temperature cycle of heating, soaking and cooling shall berecorded on a chart and a copy of the continuously temperatures shall be

provided to the Client for record. Cooling rate and heating rate shall be

recorded on the WPS.


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3. Minimum and maximum PWHT temperatures and minimum holding time

shall be as specified in the appropriate code and/or POLARIS EngineeringStandard, except as specifically noted below:

a. All carbon steel vessels, exchangers, and piping requiring PWHTare to be postweld heat treated at 1150

oF maximum ( 25

oF) for a

minimum of two (2) hours.

b. All 1-1/4% Cr - 1/2% Mo vessels, exchangers and piping are to bepostweld heat treated at 1325

oF maximum ( 25

oF) for a

minimum of two (2) hours.

c. All 5% Cr - 1/2% Mo and 9% Cr 1% Mo vessels, exchangers and

piping are to be postweld heat treated at 1350oF maximum ( 25

oF) for a minimum of two (2) hours.

d. All carbon steel and low chrome piping shall be postweld heat

treated in accordance with POLARIS Engineering Standard 840.4.

B. Postweld heat treatment may be required for carbon steel equipment and piping

for certain service conditions even when not mandatory per the applicable code or

standard. Postweld heat treatment for these services will be indicated by thePOLARIS Engineering Standards.

At a minimum the following items shall be post weld heat treated:

1. Unless otherwise specified, welds in amine equipment and piping shall be

postweld heat treated regardless of operating temperature or concentration.This also includes piping and equipment, which may be at risk of amine

contamination as defined by the project P & ID's.

2. Unless otherwise specified, welds in caustic equipment and piping shall bepostweld heat treated regardless of the operating temperature or caustic

concentration. This also includes piping and equipment, which may be at

risk of caustic contamination as defined by the project P & ID's.

3. Postweld heat treatment is required for equipment as well as shop andfield fabricated piping of 1-1/4 Cr and higher ferritic steel weldmentsregardless of thickness.

4. Postweld heat treatment is required for equipment as well as shop and

field fabricated piping of carbon steel weldments regardless of thickness

when design operating conditions are within 200oF of the Nelson Curve

for that material.

5. All carbon steel equipment and piping in sour service with a fluid pressure


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of 65 psia or greater and containing hydrogen sulfide (H2S) at a partial

pressure in excess of 0.05 psia (mol-fraction multiplied by total system

pressure) with, or without, water present.

6. All deaerators require post weld heat treatment.7. All equipment in these services above shall have welds ground, smooth,

and wet fluorescent magnetic particle tested.

C. Postweld heat treatment temperatures will be in accordance with ASME B31.3,Table 331.1.1 and POLARIS Engineering Standards 840.1 and 840.4.

D. Acceptable methods for postweld heat treatment are:

1. Furnace method

2. Local resistance method

3. Local induction method

Other methods for postweld heat treatment require Client's written approval.

E. For piping, postweld heat treatment performed by exothermic methods requiresClient's written approval and shall not be assumed as acceptable by the Vendor

during bid preparation. When approved by Client, welding procedures submitted

for review using postweld heat treatment by exothermic methods shall be

qualified as using the exothermic method proposed for heat treatment. All weldjoints postweld heat treated by exothermic methods, when approved, require

100% radiography.

F. Postweld heat treatment for stainless steels of Material Group P-8, nonferrous

materials or dissimilar materials requires approval by the Client.

G. Direct impingement by torch or furnace burner is not acceptable. Threads and

gasket surfaces shall be protected from excessive oxidation during heat treatment.

H. Equipment and piping postweld heat treated for any reason, code or process, shall

not be subjected to any further welding, hammering, pressing or forming afterpostweld heat treatment without Client approval.

I. Postweld heat treatment procedures describing cleaning requirements, heating andcooling rates, thermocouple locations, type of heating, equipment, etc., shall be

submitted to the Client for review and approval to proceed.

J. For local postweld heat treatment of thicknesses greater than 2 inches, the Vendor

shall verify that the minimum code required PWHT temperature is attained on the

unheated side of the joint. Verification may be established either by the


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attachment of thermocouples or by the submittal of test data.

K. PWHT is always required for all piping in which the wall thickness is 3/4 orgreater.

X. NON-DESTRUCTIVE EXAMINATION, TESTING AND INSPECTION

A. Non-destructive examination (NDE) shall be performed and results evaluated in

accordance with the requirements of the applicable ASME code, ANSI standard,

or API standard. Any additional NDE required above and beyond the abovementioned codes and standards shall be as specified in this Standard and other

POLARIS Engineering Standards.

B. As a minimum, or when non-destructive examination is not specified, all weldsshall be visually examined.

C. Plate 2 inches and thicker and clad material shall be 100% ultrasonically tested at

the mill with acceptance to SA-578, Level B.

D. Brinell Hardness Tests

1. Hardness tests shall be performed when PWHT is specified, and when

required by codes, standards or POLARIS Engineering Standards.Hardness test results shall be given in equivalent Brinell values regardless

of test method utilized. A test shall include one (1) examination in the

weld and one (1) in each heat affected zone at the toe of the weld.

2. Hardness tests on piping shall be taken as specified in POLARISEngineering Standards 840.1 and 840.4.

3. Hardness tests on pressure vessels, exchangers, and other equipment

where required shall be taken as follows:

a. One test for one longitudinal seam per course section, on the inside

surface where practical.

b. One test for each circumferential seam per 50 linear feet of weld,

on the inside surface where practicable.

c. One test for each major joint weld for box-type headers on air

coolers.

d. One test for each size nozzle 4 inches and over in size, if

accessible.


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e. As a minimum, one test shall be taken for each welding process

employed on pressure containing welds and also one test per

welder or welding machine operator.

f. As required in the applicable code or standard.

4. When PWHT is required, hardness tests shall be performed after PWHT.

5. Where NACE MR-0175 and/or RP-0472 are specified the hardness testing

requirements of those standards shall apply where more stringent than thisStandard.

6. Results of hardness tests shall be documented by the Vendor for review bythe Client's Inspector. The Client's Inspector shall be consulted on choice

of location for tests.

7. Hardness tests exceeding the maximum Brinell Hardness Number (BHN)

allowed shall have two more tests taken near each failed location and both

are required to be within the maximum acceptable hardness requirements.

8. Hardness test results shall be reported with the procedure qualification

record by the Vendor with submittal of welding procedure review by the

Client for the following:

a. Whenever hardness tests are required by codes or standards.

b. Whenever equipment or piping is to be postweld heat treated.

c. Whenever automatic or machine type welding processes areemployed, or whenever FCAW is to be utilized.

d. Hardness for carbon steel shall not exceed 200 BHN; hardness for

low alloy shall be in accordance with applicable codes orstandards. For other materials requiring hardness testing,

acceptance values shall be as stated in the applicable codes and

standards.

E. Production test requirements on weld overlay and back-cladding on vessels andexchangers are as follows:

1. One chemical analysis of overlay from each girth section and component(such as head, tubesheet, etc.) and from each back-cladded longitudinal

and circumferential seam. Also, back-cladded manway attachment and a

representative number of nozzles, at least one of each size. Productiontests shall include a minimum of one test per welding process utilized and

one test per welder or welding operator employed.


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2. For austenitic stainless steel, the overlay or back-clad for TP 347 stainless,

when specified, shall have elements Cr, Ni, Mn, Si, C and Cb reported.

3. For others, the overlay or back-clad shall meet the minimum requirements

of the specified alloy.

4. Ferrite content of austenitic stainless steel overlay and back-cladding shall

be checked by using a magnetic gage or other method approved by the

Client. Range of ferrite shall be 3-12 FN per magnetic meter.

F. Weld overlays and back-cladding for vessels and towers shall be examined by a

standard copper sulfate test prior to hydrostatic test and by liquid penetrant

examination following hydrostatic test. Overlay clad tubesheets shall be liquidpenetrant examined prior to hydro static test.

G. The Client's Inspector shall be authorized to reject work or materials and requirerepair or corrections where the applicable specifications or acceptance levels have

not been met.

H. The Client's Inspector may require additional examination over and above theminimum specified. If the weld proves to be acceptable, the cost of examination

shall be borne by the Client. If the weld proves to be unacceptable, the cost of the

examination, and all required repairs and re-examination shall be borne by theVendor.

I. Root and final welds in vessels, air cooler box headers, exchangers and piping

larger than 24 inches shall be magnetic particle examined when the materialthickness is equal to or greater than the following:

MATERIAL GROUP THICKNESS (INCH)

P-1 1-1/4

P-3 3/4P-4 5/8

P-5 All

P-6 AllP-7 All

J. Welds in all non-magnetic materials, either of solid alloy or alloy clad plate shallbe examined by liquid penetrant methods.

K. Where strength welds for tube to tubesheet joints are required, Vendor shall

submit a cut-off sample before fabrication.


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L. Pressure retaining butt welds in shell or heads over 1.80 inches thick may be

manual arc process welded and shall be radiographed 100%.

M. Heads fabricated from more than one piece shall have welds radiographed 100%

prior to forming.

N. For equipment and piping requiring PWHT all required NDE of completed welds

shall be performed after the postweld heat treatment.

XI. REPAIRS

A. Welding repairs shall be performed utilizing Client approved welding procedures

under conditions and requirements as stringent as those imposed by the weldingprocedure originally accepted for the particular weld.

B. The repair procedures, using welding, shall be submitted for review and shallinclude the following:

1. The method of defining the type and the extent of the defect.

2. Methods used for removing the defect, and testing conducted to ensure

that the defect has been removed.

3. Welding procedures employed for re-welding and NDE methods used to

inspect weld repair area after completion of the welding.

C. Unacceptable discontinuities shall be completely removed by chipping, gouging,grinding or other Client authorized methods (for the type of material being

repaired) to clean to sound metal and the excavated area shall be examined bymagnetic particle or liquid penetrant methods to assure complete removal of

defects.

D. Excavation for repairs by flame or arc gouging shall have the same preheatrequirements imposed as the welding procedures used to perform the weld.

E. Preheat to be used for repair welding (such as attachments, undercutting, andother defects which do not penetrate the full weld thickness) shall be the same as

required for the original weld for the full base metal thickness.

F. Undercutting shall be repaired by blend grinding provided the required base metal

thickness by design is not reduced. Otherwise, weld metal buildup will berequired.

G. Defective work or materials that have been weld repaired shall, as a minimum, bere-examined by the same non-destructive test method by which the defect was

originally located.


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H. Only two repair attempts shall be allowed on any one defective area. No further

attempts to repair shall be carried out without authorization of the Client.

XII. SUMMARY OF WELDING VARIABLE LIMITATIONS, RESTRICTIONS,

AND OTHER REQUIREMENTS

Limitations, restrictions and other requirements of this Standard, whether required by

ASME Section IX or not, are required to be stated in the Vendor's WPS, PQR and weld

map (Appendix I), on welding procedures submitted by the Vendor for review. The main

requirements are summarized as follows:

A. Impact test results on PQR.

B. Brinell hardness test results on PQR.

C. Mode of transfer for GMAW and FCAW to be stated on WPS and weld map ofAppendix I.

D. GMAW: Limitations and requirements.

E. FCAW: Limitations and requirements.

F. Automatic or machine type SAW to be specified in WPS.

G. Filler metals and fluxes. To have stated in the WPS and/or weld map (Appendix

I) the AWS grades ASME specifications, Manufacturers, and trade names of filler

metals and fluxes.

H. When backing is approved for use, it is required to be stated on PQR, WPS andweld map (Appendix I).

I. Root shielding (back purge) method to be stated on WPS or separate procedure

submitted.

J. Minimum preheat temperature to be stated in WPS.

K. Preheat maintenance when required to be stated in WPS.

L. Maximum preheat and interpass temperature to be stated on WPS for P-7 groupmaterials and higher.

M. Postweld heat treatment holding temperature and holding time to be specified on

weld map (Appendix I) and in WPS.

N. Additional welding variables to be stated in the WPS whether essential or non-

essential per ASME Section IX are:


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1. Electrical characteristics: current and voltage ranges, and polarity, for all

welding processes.

2. AWS specification for non-consumable electrode for GTAW.

3. Travel speed and whether single or multiple arc for automatic processes ofGTAW, GMAW, SAW, FCAW/CO2 and for overlay and back-clad

welding.

4. Amount of bead overlap, extent of oscillation and wire size for overlayand back-clad welding.

O. Block welding is prohibited. However, The Temper Bead Welding Technique perNBIC is allowable with Clients written approval.

P. When welding titanium, each bead and adjacent base metal shall be cleaned toremove all surface discoloration prior to deposition of the next bead. The final

weld surface may have intermittent, iridescent straw-colored oxides.

Q. The root pass of butt welds in lube oil piping, accessible from one side only, shallbe welded with the GTAW process.

XIII. PROCEDURE FOR REVIEW AND ACCEPTANCE OF VENDOR WELDINGPROCEDURES

A. The Client requires Vendors and their Subvendors, if applicable, to submit a copy

of each welding procedure appropriate for fabrication. A copy of the weld map(Appendix I) shall also be filled out and attached to the submittal. Procedures

cannot be reviewed unless accompanied by the weld map.

B. Submittals of welding procedures for review shall be directly to the Client and/or

Client's Engineer. No portion of this Standard shall be waived without written

approval.

C. Vendors shall review the welding procedures of their own Subvendors for

compliance to this Standard prior to submitting for review and acceptance.

D. The Client and/or Client's Engineer will review the submitted welding proceduresand weld map and make comments back to the Vendor in writing. Comments areeither (1) Acceptable without comment, (2) Acceptable with comments, (3)

Revise and resubmit per comments or (4) Unacceptable with comments. Allcomments, if possible, will make reference the paragraph number of this Standard

with which the procedure must comply.


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E. Upon receiving the marked up welding procedure from the Client and/or Client's

Engineer, the Vendor must comply with the comments. The Vendor shall submit

corrected documents. The Surveillance Inspector assigned by the Client is toverify that welding will be performed to the accepted and corrected welding

procedures, which incorporate the comments. Items in dispute shall be resolvedprior to fabrication being stated on the affected parts.


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APPENDIX I

WELD MAPSupplier Name

Supplier Shop Order #

POLARIS PO # Pressure Vessel

Item/Tag # Heat Exchanger

Storage Tank

Design Temperature Fabricated Pipe Spools

Design Pressure Other

Min. Design Metal Temp.

Postweld Heat Treatment Yes No Required by Code Service

Time and TemperatureImpact Testing Yes No Required by Code ServiceTemperature

Applicable Code or Standard

Draw a single-line sketch of the apparatus. For pipe spools, only show typical weld joints, i.e., butt, branch, and attachments, byP-No.Locate an example of all types of typical weld joints, dissimilar welds & attachments

Identify each different welding procedure by separate letter or number.

This form completed by This space for POLARIS Review Stamp

Email Address

Telephone

Revision

Date

This space for POLARIS Identification

general welding fabrication and testing

Documents