GS PVV 612

Exploration & Production

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GS PVV 612.doc

GENERAL SPECIFICATION

PIPING VALVES VESSELS

GS PVV 612

Piping and Equipment subject to Severe Sour ServiceMetallurgical and welding requirements

02 10/03 Change of Group name and logo

01 10/02 New revision

00 03/01 First issue

Rev. Date Notes


General Specification Date: 10/03

GS PVV 612 Rev: 02


GS PVV 612.doc Page 2/17

Contents

1. Scope .......................................................................................................................4

2. Reference documents.............................................................................................4

3. General.....................................................................................................................63.1 Use of Stainless steel...................................................................................................... 63.2 Metallic overlay ............................................................................................................... 6

4. Pressure vessels and heat exchangers ................................................................64.1 Carbon steel plates (including plates for heads).............................................................. 64.2 Fittings and flanges......................................................................................................... 84.3 Other construction materials ........................................................................................... 9

5. Piping materials ......................................................................................................95.1 Pipes............................................................................................................................... 95.2 Forgings........................................................................................................................ 105.3 Castings........................................................................................................................ 115.4 Bolting........................................................................................................................... 115.5 Bellows ......................................................................................................................... 125.6 Springs and spring lock washers................................................................................... 125.7 Metallic coating and surface treatment.......................................................................... 125.8 Material certificates and material traceability................................................................. 13

6. Qualification tests .................................................................................................136.1 Welding procedures qualification tests .......................................................................... 136.2 Fabrication Tests .......................................................................................................... 14

7. Fabrication.............................................................................................................147.1 General......................................................................................................................... 147.2 Welding......................................................................................................................... 157.3 Filler materials............................................................................................................... 157.4 Post Weld Heat Treatment (PWHT) .............................................................................. 167.5 Sour service with alkalis/amines ................................................................................... 16

8. Identification, stamping, marking ........................................................................168.1 H2S Marking.................................................................................................................. 16



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8.2 Hard stamps ................................................................................................................. 16

9. Inspection ..............................................................................................................179.1 General......................................................................................................................... 179.2 Hardness checking ....................................................................................................... 179.3 Hardness checking on small items................................................................................ 179.4 Hardness checking on welds......................................................................................... 179.5 Corrosion resistant alloy................................................................................................ 17



GS PVV 612 Rev: 02



1. ScopeThis General Specification covers the specific requirements applicable to equipment such aspressure vessels or heat exchangers, and to piping materials, which are intended to be used inSevere Sour Service Conditions as defined in General Specification GS COR 170.The present General Specification makes major reference to the NACE Standard MR 01-75. Itstates additional requirements with respect to Hydrogen Induced Cracking (HIC) and to SulfideStress Cracking (SSC) where the NACE document is insufficient.Transmission pipelines are outside the scope of this specification and are covered in otherdocuments issued by the COMPANY GS PLR xxx (see GS PLR 000).Valve materials shall comply with both this specification (for cast or forged materials, includingweldments if applicable), and the COMPANY General Specification GS PVV 613.

2. Reference documentsThe reference documents listed below form an integral part of this General Specification. Unlessotherwise stipulated, the applicable version of these documents, including relevant appendicesand supplements, is the latest revision published at the EFFECTIVE DATE of the CONTRACT.Since this specification brings additional requirements dealing with a specific application (i.e.H2S service), it is deemed to overrule any less stringent requirements appearing in any of theother contractual Reference Documents.Any divergence between any of the contractual Reference Documents and this specificationmust be reported to the COMPANY for decision. In such a case, and unless otherwise agreedor decided by the COMPANY, it is understood that the more stringent requirement shall apply.Exceptions to, or deviations from this specification are not permitted unless previously acceptedin writing by the COMPANY. For this purpose, Manufacturer's requests for substitution orchange of any kind shall be complete with all pertinent information required for the COMPANYassessment. In case of approval, such approval shall be valid only for a specific case and shallnot be construed as having general validity for other applications

Standards

Reference TitleEN 10204 Steel and Steel Products - Inspection DocumentsASTM E 45 Standard Test Methods for Determining the Inclusion Content of

SteelASTM A 578 Standard Specification for Straight-Beam Ultrasonic Examination

of Plain and Clad Steel Plates for Special ApplicationsASTM A 770 Standard Specification for Through-Thickness Tension Testing of

Steel Plates for Special ApplicationsASTM A 106 Standard Specification for Seamless Carbon Steel Pipe for High-

Temperature Service



GS PVV 612 Rev: 02



Reference TitleASTM A 333 Standard Specification for Seamless and Welded Steel Pipe for

Low-Temperature ServiceASTM E 92 Standard Test Method for Vickers Hardness of Metallic MaterialsASTM A 307 Carbon Steel Bolts and Studs, 60 000 Psi Tensile StrengthASTM A 193 Alloy-Steel and Stainless Steel Bolting Materials for High-

temperature ServiceASTM A 320 Alloy-Steel Bolting Materials for Low-temperature ServiceASTM A 194 Carbon and Alloy-Steel Nuts for Bolts for High-pressure and High-

temperature Service

Professional Documents

Reference TitleAPI 5L Specification for LinepipeAPI RP 945 Avoiding Environmental Cracking in Amine UnitsNACE MR 01-75 Standard Material Requirements. Sulfide Stress Cracking.

Resistant Metallic Materials for Oilfied Equipment

Regulations

Reference TitleNot applicable

Codes


Other documents


Total General Specifications

Reference TitleGS COR 170 Materials for sour service (upstream applications) Specification for

designGS PLR 000 General Specification Catalogue



GS PVV 612 Rev: 02



Reference TitleGS PVV 611 Welding of pressure containing piping and equipmentGS PVV 613 Valve materials requirements for use in sour service

3. General

3.1 Use of Stainless steelStainless steel can be used for some parts of equipment. If so, the following requirements andrestrictions shall be applied:

• 13% Cr Stainless steel shall be heat-treated and have a hardness complying with NACEStandard MR 01-75, Section 3.7

• Austenitic or austenitic-ferritic stainless steel shall be in the solution annealed condition

• If welding and/or post-weld heat-treatment is required on austenitic stainless steel, thissteel shall be low carbon or titanium-stabilised steels

• If welding repairs are required to the bodies of cast equipment in type 304 or 316 stainlesssteel, the procedure shall be subject to approval

• Parts of austenitic stainless steel cold-formed by rolling, bending or stamping shall bequench-annealed a second time if the permanent deformation exceeds 15%

• In all cases, limits of use of stainless steel and the suitability of alternative material forspecific applications shall be sought from the COMPANY.

• Any equipment or process pipework made of austenitic or austenitic-ferritic stainless steelor nickel base alloys shall comply with NACE Standard MR 01-75 requirements withrespect to hardness level and heat treatment (if any) unless otherwise approved by theCOMPANY.

3.2 Metallic overlayExplosively clad, roll bonded or fusion-bonded corrosion resistant overlay such as austenitic oraustenitic-ferritic stainless steel or nickel alloy are considered to be effective barriers to thesulphide environment when they are within their safe limit of use. Where such overlays areemployed the backing material need not to conform to this Specification.

4. Pressure vessels and heat exchangers

4.1 Carbon steel plates (including plates for heads)The following requirements shall apply to pressure vessels and heat exchangers fabricated ofunalloyed carbon steel.

4.1.1 Manufacturing processPlates shall be produced by a low sulphur and low phosphorus refining process such as in anelectric furnace, with double deslagging, or in a basic oxygen furnace. The steel shall bevacuum degassed while molten; if manufactured by the continuous casting method, preferenceis given for magnetic stirring and squeeze rolling to prevent centrelines segregation.



GS PVV 612 Rev: 02



Plates shall be supplied in the normalised condition. Controlled rolled or quenched andtempered plates are not acceptable except by special arrangement (acceptance based on HICtest results).Plate materials shall receive an appropriate inclusion shape control treatment by addition ofCalcium. Specific treatment by rare earth metals is not permitted.

4.1.2 Repair of defects by welding is not permitted. Particular inspection of finishedproductsIn addition to what is already required in the plate material specification, the followingexamination must be performed:

4.1.2.1 Micro-examinationThe plates shall be checked for microstructure from the full thickness, at the center, quarterwidth, and at each edge, for confirmation of effectiveness of shape control of the inclusions. Thesample shall be typical of normal production material.Plates rolled from continuous cast material shall be checked at one end of each plate. Platesrolled from ingots shall be checked at both ends of each plate. The examination method shallconform to the ASTM E 45 standard (microscopical method, method D, with [A + B + C + D]≤ 20).

4.1.2.2 Ultrasonic examinationUltrasonic tests shall be performed according to ASTM A 578 level II.

4.1.3 Chemical compositionThe chemical analysis (ladle) of plate materials shall be within the following limits (all values inpercent, by weight):

• C < 0.20

• Si < 0.35

• Mn < 1.0

• Cr < 0.25

• Mo < 0.05

• Ni < 0.15

• Cu < 0.40

• Nb ≤ 0.005 [1]

• V ≤ 0.005

• P < 0.015

• S < 0.008

[1] If CE (IIW) ≤ 0.360, Vanadium and Niobium contents may be increased up to the following values: Nb < 0.05 & V < 0.08, with

V + Nb < 0.08



GS PVV 612 Rev: 02



• Ca < 0.025 with 4S

Ca2 ≤≤ and 1.5O0.625S1.25

Ca ≥×+×

[2]

• B < 0.0005

• A1 (Total) < 0.045

• Ti < 0.02

• O < 0.002

• N < 0.010

• Ni + Cu < 0.15

• Nb + V + Ti + Cu + Mo + Cr < 0.50

• CE (IIW) ≤ 0.420 or CE (Pcm) < 0.190 [3]

4.1.4 Plate Material certificateMaterial certificates shall be of the EN 10204 3.1B type and shall give the following information:

• Full chemical analysis

• Mechanical properties (as required in the material specification)

• Steel making process, desulfurisation technique, method of monitoring inclusion shapecontrolCasting method and size of ingots/slabsRolling procedures.

• Results of ultrasonic inspection

• Results of micro-examination.

4.2 Fittings and flangesAll carbon steel fittings and flanges for pressure vessels shall be supplied in accordance withsection 5.2 of this specification (i.e. "forgings").

4.2.1 Internal boltingAll internal bolting subject to sour environments shall be selected to be resistant to SSC (seeSection 5.4 of this Specification).

[2] Calcium treatment is not necessary if S ≤ 0.002[3] CE (IIW) ≤ 0.430 is acceptable for plates in thicknesses 2 inches and above

If C < 0.12, CE (Pcm) shall apply and if C > 0.12, CE (IIW) is only applicable.

CE (Pcm) and CE (IIW) are defined as follows:

5B10V

15Mo

60Ni

20CrCuMn

30Si

CCE(Pcm) ++++++

++=

15CuNi

5VMoCr

6Mn

CCE(IIW)+

+++

++=



GS PVV 612 Rev: 02



4.3 Other construction materialsPressure vessels in sour service constructed from materials other than carbon, carbonmanganese and low-alloy steel e.g. austenitic or austenitic-ferritic stainless steel or internallyclad vessels or other high alloy corrosion resistant alloy shall be subject to the COMPANY forapproval.

5. Piping materials

5.1 Pipes

5.1.1 Seamless pipesSeamless carbon steel pipes shall be supplied to the requirements of API 5L (grades B to X 60inclusive), or ASTM A 106 grade B, or A 333 grade 6, with the following additional requirementsfor chemical analysis (maximum values in weight, percent, based on ladle analysis):

• C < 0.20

• Mn < 1.30

• Si < 0.35

• P < 0.020

• S < 0.010

With:

• Mn < (1.6 - 60 S)

• Cu < 0.40

• Mo < 0.05

• Nb ≤ 0.005

• V ≤ 0.005[1]

• CE (IIW) ≤ 0.420

with 15

CuNi5

VMoCr6

MnCCE(IIW) ++++++=

Repair by welding of out of tolerance defects is not acceptable.

5.1.2 Welded pipesWelded carbon steel pipes shall be supplied to the requirements of API 5L grades B to X 60inclusive, or A 333 grade 6, with the following additional requirements:Welded pipes shall be made from plates complying with Paragraph. 4.1 of the presentdocument (i.e., plates for pressure vessels).


V + Nb < 0.08



GS PVV 612 Rev: 02



Welded pipes shall be Longitudinal Seam Submerged Arc Welded (SAWL) with a least twopasses, one inside and one outside, and with a filler materials with a nickel content of not morethan 1.00%.Spiral welding and Electric Resistance Welding (ERW) fabrication processes are not allowed.Longitudinal welds must comply with section 6 (Qualification tests) and section 7 (Fabrication) ofthis specification with the following specific requirements:

5.1.2.1 Chemical analysis

CE (IIW) ≤ 0.320 with 15

CuNi5

VMoCr6

MnCCE(IIW) ++++++=

5.1.2.2 Welding energyWelding energy must be equal to or greater than 12 kJ/cm for longitudinal seams.

5.1.2.3 Post Weld Heat TreatmentNo post weld heat treatment is required on longitudinal welds, except if otherwise called for inthe product specification, in the design code or in other contractual documents.

5.2 Forgings

5.2.1 Process of manufactureCold work or machining from bars is not permitted.Hot work operations must be followed by an appropriate heat treatment with the followingdecreasing order to preference:

• Quenching and tempering

• Normalisation and tempering

• Normalisation.Repair by welding is not allowed.

5.2.2 Chemical analysisThe chemical analysis (ladle) of forgings shall be within the following limits (all values in percent,by weight):

• C < 0.20

• Mn < 1.30

• P < 0.020

• S < 0.015

• Nb ≤ 0.005



GS PVV 612 Rev: 02



• V ≤ 0.005[1]

• CE (IIW) ≤ 0.420

with 15

CuNi5

VMoCr6

MnCCE(IIW) ++++++=

(However, the limitation on carbon equivalent values does not apply if items are not welded andare not supposed to be welded in the future).

5.3 CastingsCast iron is not acceptable.

• All castings shall be suitably heat treated after any welding operation has been performed,and this requirement also applies to the weld repair of defects, irrespective of size. Thechemical analysis of castings must comply with the following: Mn < 1.35

• P < 0.020

• S < 0.020

• CE (IIW) ≤ 0.420

with 15

CuNi5

VMoCr6

MnCCE(IIW) ++++++=

(However, the limitation on carbon equivalent values does not apply if items are not welded andare not supposed to be welded in the future).

5.4 Bolting

5.4.1 GeneralBolting shall comply with NACE Standard MR 01-75 requirements when in contact with anyconcentration of wet H2S.

5.4.2 MaterialsFerritic steel bolts and nuts shall conform to Section 6 of the NACE Standard MR 01-75. As anexample, the following materials are acceptable:Threaded rods:

• ASTM A 307 grade B, carbon steel with grain refinement or normalising after manufactureif cold-formed. Maximum hardness 22 HRC

• ASTM A 193 grade B7M and ASTM A 320 grade L7M Cr Mo steel with maximumhardness 22 HRC.


V + Nb < 0.08



GS PVV 612 Rev: 02



Nuts:• ASTM A 194 grade 2HM, carbon steel, maximum hardness 22 HRC

• ASTM A 320 grade L7M maximum hardness 22 HRC.Where austenitic stainless steel bolts and nuts are required, these items shall be free from coldwork; they shall be solution treated after thread forming, etc. as outlines as follows:

• Bolts shall be Class 1A of ASTM A 193 e.g. B8MA (type 316) solution treated after all coldwork including thread forming)

• Nuts shall be of the "A" suffix variety of ASTM A 194 e.g. Grade 8MA (type 316) solutiontreated after all hot or cold working.

Resulphurized steel are not acceptable.

5.5 Bellows

5.5.1 GeneralBellows shall comply with the NACE Standard MR 01-75 requirement when in contact with anyconcentration of wet Hydrogen Sulphide (see GS COR 170).

5.5.2 MaterialsAustenitic stainless steel shall not be used for bellows, beyond 50% of their minimum specifiedyield strength otherwise material selection may be made according to the process conditionsfrom the following:

• Alloy 825 (UNS N 08825)

• Alloy 625 (UNS N 06625)

• Alloy 400 (UNS N 04400).

Other materials may be proposed for approval by the COMPANY.The production procedure shall comply with the requirements of the NACE Standard MR 01-75.

5.6 Springs and spring lock washers

5.6.1 MaterialsSprings shall be made of a material resistant to environmental corrosion cracking in thepresence of H2S and shall comply with this Specification.The materials may be selected from among alloy 600 (UNS N 06600), alloy 625 (UNSN 06625), alloy X718 (UNS N 07718), alloy 825 (UNS N 08825), alloy 400 (UNS N 04400), alloy17-4 PH (UNS S 17400), low alloy CrMo steel (steel 41XX and its modifications).

5.7 Metallic coating and surface treatment

5.7.1 Metallic overlayExplosively clad, roll bonded or fusion-bonded corrosion resistant overlay are considered to beeffective barriers to the sulphide environment as long as they do not suffer from fabricationdefects susceptible to alter overlay tightness and to allow a path to the backing material for theH2S containing fluid.



GS PVV 612 Rev: 02



5.7.2 Metallic coatingElectroless deposited nickel/phosphorus or electroless deposited nickel/phosphorus alloy for thefirst plating, followed by electro-deposited chromium plating are acceptable. The procedures aresubject to approval.Cadmium plating and galvanisation are prohibited, because these metals corrode rapidly incontact with H2S.

5.7.3 Other surface treatmentsChromizing, chromating, nitriding or liquid or gas phase carbonitriding are unacceptable forgood resistance to sulphide stress cracking in the presence of H2S.

5.8 Material certificates and material traceabilityMaterial certificate shall clearly mention that the material is adequate for sour service.Type 3-1-B certificates must be supplied for all piping materials. These certificates must includea full chemical analysis sufficiently detailed to show that the relevant chemical element contentscriteria are met for each type of material.The COMPANY reserves the right to perform any counter-analysis, particularly on chemicalanalysis of finished products, to ascertain the correctness of the material certificates submittedwith the supply.All piping bulk materials must be fully traceable and correctly identified, particularly to the heatand test numbers of the matching certificates.

6. Qualification tests

6.1 Welding procedures qualification tests

6.1.1 GeneralEach particular welding procedure shall be specially qualified for the job; no previous testreports shall be recognised as a qualification of the work to be performed.The tests shall be carried out according to the requirements of the contractual documents and,in particular, shall comply with the COMPANY General Specification GS PVV 611.Laboratory tests shall be performed in an official laboratory approved by the COMPANY.Sufficient advance notice shall allow the COMPANY to witness all or part of the tests at theirdiscretion.

6.1.2 Materials for the testsThe materials for the tests shall be selected among those of the greatest values of carbonequivalents and maximum thicknesses that are intended to be used on fabrication.

6.1.3 Particular requirements for Hardness TestsEach qualification test shall include a cross-section hardness survey with VICKERS hardnesstesting under 5 kg load.



GS PVV 612 Rev: 02



In lieu of what is required in the specification GS PVV 611, a complete survey of the HeatAffected Zone shall be performed according to the following procedure:

• The test method shall be per ASTM E 92 standard

• The distance between indentations shall be a maximum of 1 mm

• The location of each indentation shall be in the most critical microstructure as far ashardness is considered and shall be approximately at 0.3 mm from the fusion line in thebase material

• The results shall not exceed 250 HV5. However, isolated values up to 260 HV5 areacceptable if any three adjacent measures in the HAZ show results not exceeding250 HV5.

6.1.4 Microstructure examinationAn optical examination of the microstructure shall be performed at a magnification of 200.Untempered martensite is not acceptable, even in small amount.

6.1.5 Corrosion testsHIC and SSC corrosion tests are not in the scope of the present specification. However, suchtests may be specified at the time of the purchase order, or could also be required by theCOMPANY during the qualification tests or during the fabrication, to clarify a particular technicalsituation.In that case, the procedures would be based on the recommendations of GS COR 170 unlessotherwise agreed or specified.

6.2 Fabrication TestsIn case fabrication tests are required in the contractual documents, they shall include hardnesstests and microstructure examination with the same acceptance criteria as stated in 6.1.3 and6.1.4 above.The materials for the tests, as well as the number of tests, shall be subject to the COMPANYapproval, and shall be based on the same rules as on 6.1.1 and 6.1.2 above.

7. FabricationNo fabrication shall start until the COMPANY has approved the chemical analysis of thematerials and the results of the Welding Procedure Qualification Tests.

7.1 GeneralIn addition to the general and detailed requirements below, the Manufacturer shall comply withthe following:

• Design and/or fabrication rules described in the regulations in force and the constructioncode adopted

• The maximum service or hydrostatic test stresses (including re-testing) limited to 80% ofthe minimum specified yield stress, for equipment corresponding to severe sour serviceconditions

• Limitation to the strict minimum of the number of taps and nozzles on pressure vessels.



GS PVV 612 Rev: 02



The welding of temporary parts shall be limited to the minimum. No arc striking shall beaccepted outside the bevel. Welds of temporary parts and accidental arc striking shall beground. The ground zone shall be subject to magnetic particle or dye penetrant examination.

7.2 WeldingThe welding parameters shall be set up to the following minimum values:

• Welding energy: 10 kJ/cm

• Preheating, according to the following table (minimum values):

Thickness of materialWelding energy below 15 mm 15 to 25 mm above 25 mm

10 kJ/cm not required 100°C 150°C



19 kJ/cm and above not required 50°C

Preheating temperatures shall be obtained by permanent heating systems for temperaturesrequired at 150°C and above.

7.3 Filler materials

7.3.1 Homogeneous jointFiller materials shall be selected in accordance with the characteristics of the base metal.The use of filler materials designed to obtain a deposit with very low diffusible hydrogen (lessthan 5 cm3/100 g of metal deposited) is mandatory for all welds in contact with effluentcontaining H2S.

The filler materials used shall have a maximum nickel content of 1.00%.

7.3.2 Heterogeneous composite jointsFor welded joints of a carbon steel and a stainless steel, precautions shall be observed inselecting the filler materials and in executing the welds, according to whether the joint is heat-treated or not after welding:

7.3.2.1 Non heat treated jointsThe filler material shall be of type 24Cr12Ni or 20Cr10Ni3Mo according to the dilution and gradeof the stainless steel.

7.3.2.2 Heat treated jointsThe fabrication procedure may be as follows:

• Buttering of the bevels on carbon steel with filler materials 75Ni10Cr type AWS A 5.11class E NiCrFe3, or preferably with nickel filler materials type AWS A 5-1, Class E Ni1, toobtain an added thickness of at least 8 mm after re-machining of the bevel



GS PVV 612 Rev: 02



• Execute the heat treatment selected for the carbon steel

• Re-machine the bevels

• Weld the stainless steel part with the filler materials of type 20Cr10Ni3MoNb, if butteringhas been carried out with materials of type AWS E NiCrFe3, or with materials of typeAWS E NiCrFe3, if the buttering has been carried out with materials of type AWS A 5-11,Class E Ni1.

7.4 Post Weld Heat Treatment (PWHT)All equipment and pipework in carbon steel and low alloyed carbon steel must be subject to apost weld heat treatment, irrespective of their thickness, except for socket welds on sizes lessthen two inches in diameter.The post weld heat treatment must be performed in accordance with the requirements of thedesign code even though the thickness of the material may be below the minimum valuerequiring such a heat treatment. The soaking time must be a minimum of one hour; the heattreatment temperature shall be a minimum of 600°C ± 10°C.

7.4.1 Approval of heat-treatment procedureFor equipment which is to be post-weld heat treated, the following information shall besubmitted to the COMPANY for approval:

• Details of the method of heating, e.g. furnace, electric resistance, induction, etc.

• Details of the position of thermocouples

• Special requirements for heat-treatment, e.g. if it were proposed to post-weld heat treat aheat-exchanger tube bundle incorporating tube end welding

• Copies of relevant heat treatment charts on completion.

7.5 Sour service with alkalis/aminesFor sour service in association with alkalis, amines or other alkaline process fluids, which arerelated to down stream applications, API RP 945 and the COMPANY requirements shall be thesystematic post weld heat treatment of welds with the exception of low pressure storage tanks.

8. Identification, stamping, marking

8.1 H2S MarkingThe identification:“PVV 612”of each piece supplied in accordance with this specification, shall be carried out by coldstamping surrounded by yellow paint. The use of low stress stamps is mandatory.

8.2 Hard stampsConventional sharp "V" stamping is acceptable only on the outer circumferences of flanges.Round "V" stamps may be used elsewhere, providing the identities are placed on the externalsurfaces of low stress areas.



GS PVV 612 Rev: 02



9. InspectionIn addition to normal inspection, the following shall apply:

9.1 GeneralDocumentation and inspection shall be provided to prove the identities of all materials ofconstruction and to establish that the correct heat treatment has been applied so that thefinished product complies fully with this Specification. All material certificates shall be inaccordance with EN 10204 3.1B or EN 10204 3.1C as specified, or the Supplier may submitalternative proposals for approval by the COMPANY.

9.2 Hardness checkingWhere the hardness can be checked without damaging the component, the Manufacturer shallconduct hardness tests to ensure that the hardness requirements of this Specification are met.Additionally, the COMPANY inspectors may carry out random hardness checks. Wherehardness values in excess of the requirements of this Specification and the NACE StandardMR 01-75 are obtained the part shall be rejected. This requirement does not apply to austeniticalloy supplied in the solution annealed condition.

9.3 Hardness checking on small itemsFor small items, e.g. small springs, pins, etc. which cannot be hardness tested individually, theManufacturer shall conduct tests on a random basis by selecting components from productionruns or stores batches to ensure that the product complies fully with this Specification.Procedures for doing this shall be subject to approval by the COMPANY. This requirement doesnot apply to austenitic alloy supplied in the solution annealed condition.

9.4 Hardness checking on weldsFor welded components, hardness measurements can only realistically be taken in weld metaland parent material. Acceptability of heat affected zone hardness shall be based on HVmeasurements, on (i) welding procedure qualifications tests and (ii) production test plates, whenthese are required by the fabrication specifications.

9.5 Corrosion resistant alloyFor all corrosion resistant alloys, it shall be proved to the satisfaction of the inspector that thespecified heat treatment has been carried out correctly.