ASTM A262 2015 奥氏体不锈钢晶间腐蚀敏感性检测标准方法 - 图文

A262?15

TABLE2UseofEtchStructureClassi?cationfromOxalicAcid

EtchTestwithNitricAcidTestAGradeAISI304AISI304LACICF-8ACICF-3

AAcceptableEtchStructures

Step,dual,endgrainStep,dual,endgrainStep,dual,isolatedferriteStep,dual,isolatedferrite

II

poolspools

SuspectEtchStructuresBDitch,endgrainIIDitch,endgrainII

Ditch,interdendriticditchesDitch,interdendriticditches

30.3Heater—Ameansforheatingthetestsolutionsandofkeepingthemboilingthroughoutthetestperiod.Anelectricallyheatedhotplateissatisfactoryforthispurpose.

30.4Balance—Ananalyticalbalancecapableofweighingtoatleastthenearest0.001g.

30.5Desiccator—Forstorageofpreparedspecimenspriortotesting.

31.NitricAcidTestSolution

31.1Thetestsolutionshallbe65.060.2weight%asnitricaciddeterminedbyanalysis.

31.2Preparethissolutionbyaddingreagentgradenitricacid(HNO3Table3)toreagentwaterattherateof108mLofreagentwaterperlitreofreagentnitricacid.

31.3(Warning—Protecttheeyesanduserubberglovesforhandlingacid.Placethetest?askunderahood.)

31.4ThenitricacidusedshallconformtotheAmericanChemicalSocietySpeci?cationsforReagentChemicalsandtheadditionalrequirementsofthistestmethodasshowninTable3.32.Sampling

32.1Obtainandprepareonlybasemetalsamples.

32.1.1Therearetwoclassesofspecimenstobeconsidered:basemetal,andprocess-affectedmetal.Process-affectedmetalcontainsanyconditionthataffectsthecorrosionpropertiesofthematerialinanon-uniformway,suchas(butnotlimitedto)welds;carburized.nitrided,oroxidizedsurfaces;mechanicaldeformation;andareasaffectedbyheat.Basemetalhasnoneoftheseconditions.

32.1.2ThePracticeCtestinvolvesimmersingtheentirespecimenandaveragingthemasslossovertheentiresurfaceofthespecimen.Welding,carburization,mechanicaldeformation,andthelike,affectonlypartofaspecimen.

32.1.3Themasslossratefromprocess-affectedmetalisexpectedtodifferfromthatfrombasemetal;thepresenceofprocess-affectedmetalinaspecimenwillaffectthecalculatedtestresultinanunpredictableway.

32.1.4Ifthepresenceoftheseorotherlocalizedconditionsisaconcerntothepurchaser,thenteststhatdonotaveragethemasslossoverthetotalspecimensurfacearea,suchasPracticeA,theOxalicAcidEtchTest,orPracticeE,theCopper–CopperSulfate–SulfuricAcidTestforDetectingSusceptibilityto

TABLE3NitricAcidCompositionLimits

Minimum

NitricAcid(HNO3),masspercentAsh,ppm

ChlorideasCl,ppmSulfate,as(SO4),ppmArsenic(As),ppmHeavymetals,asPb,ppm

Iron,(Fe),ppm

AdditionallimitsperPracticesA262Fluorine(F),ppm

Phosphate(PO4),ppm

69.0{{{{{{

Maximum71.050.510.010.20.2

GradesnotlistedinthistableeitherhavenotbeenevaluatedforuseofPracticeAwithPracticeBorhavebeenfoundtogiveacceptableresultsintheetchtestwhilegivingunacceptableresultsinPracticeB.InthelattercasePracticeAwouldpassmaterialthatshouldhavebeensubjectedtotheferricsulfate-sulfuricacidtest.BSpecimenshavingthesestructuresshallbetestedinthenitricacidtest.

givenarapidscreeningtestinaccordancewithproceduresgiveninPracticeA,OxalicAcidEtchTestforClassi?cationofEtchStructuresofAusteniticStainlessSteels.Theuseoftheetchstructureevaluationsinconnectionwiththenitricacidtestisspeci?edinTable2.

29.2Heattreatthematerialinaccordancewith33.1priortoperformingtheetchtest.

29.3Ignore“process-affected”areas,ifany(seeSection32);applicationofthenitricacidtesttoprocess-affectedareasiscurrentlyoutsidethescopeofPracticeC.

29.4Corrosiontestspecimenshavingacceptableetchstruc-turesintheOxalicAcidEtchTestwillbeessentiallyfreeofintergranularattackinthenitricacidtest;suchspecimensareacceptablewithouttestinginthenitricacidtest.Allspecimenshavingsuspectetchstructuresshallbetestedinthenitricacidtest.

30.Apparatus

30.1Container—A1-LErlenmeyer?askequippedwithacold?nger-typecondenser,asillustratedinFig.9.

30.2SpecimenSupports—Glasshooks,stirrups,orcradlesforsupportingthespecimensinthe?askfullyimmersedatalltimesduringthetestandsodesignedthatspecimenstestedinthesamecontainerdonotcomeincontactwitheachother.

{{10.2

FIG.9FlaskandCondenserforNitricAcidTest

9

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IntergranularAttackinAusteniticStainlessSteels,shouldbelossofthespecimenduringtheearlypartofthetest.

considered.Detailsofthetestandacceptancecriteriashallbeasagreedbythepurchaserandproducer.

33.6Thestandardtestistotestonlyonespecimenofeachmaterialorlotofmaterial.However,incaseofdispute,theuse32.2Unlessotherwisespeci?edbythepurchaser,thepro-ofatleasttwospecimensforcheckpurposesisrecommended.ceduresforobtainingrepresentativebasemetalsamples,forremovingthespecimensfromthesamples,andthenumberof34.Procedure

specimensshallbeatthediscretionoftheproducer.34.1Useasufficientquantityofthenitricacidtestsolution32.3Whenspecimensarecutbyshearing,theshearededgestocover2thespecimensandtoprovideavolumeofatleast20shallbere?nishedbymachiningorgrindingpriortotesting.mL/cm(125mL/in.2)ofspecimensurface.Normally,avolumeofabout600mLisused.

33.PreparationofTestSpecimens

34.2Useaseparatecontainerforeachtestspecimen.

33.1Heattreatextra-lowcarbonandstabilizedgradesat34.2.1Asmanyasthreespecimensmaybetestedinthe650to675°C(1200to1250°F),whichistherangeofsamecontainerprovidedthattheyallareofthesamegradeandmaximumcarbideprecipitation,priortotesting.Thelengthofallshowsatisfactoryresistancetocorrosion.

timeofheating,andthemethodofsubsequentcoolingusedfor34.2.2Ifmorethanoneofthespecimenstestedinthesamethissensitizingtreatmenttogetherwiththecorrespondingcontainerfailtopassthetest,retestallthespecimensinmaximumpermissiblecorrosionrateshallbeasagreedbe-separatecontainers.

tweenthematerialproducerandpurchaser.

NOTE14—Excessivecorrosionofonespecimenmayresultinacceler-Natedcorrosionoftheotherspecimenstestedwithit.ExcessivecorrosionOTE11—Themostcommonlyusedsensitizingtreatmentis1hat675°C(1250°F).

mayoftenbedetectedbychangesinthecolorofthetestsolution,anditNmaybeappropriatetoprovideseparatecontainersforsuchspecimensOTE12—Thesizeandshapeofthespecimenmustbeconsideredwithrespecttoavailablefacilitiesforaccurateweighingandthevolumeoftestwithoutwaitinguntiltheendofthetestperiod.Arecordshouldbemadesolutiontobeused.Normally,themaximumconvenientweightofashowingwhichspecimensweretestedtogether.

specimenisabout100g.Inthecaseofbar,wire,andtubularproducts,the34.3Afterthespecimenshavebeenplacedintheacidintheproportionofthetotalarearepresentedbytheexposedcrosssectionmaycontainer,passcoolingwaterthroughthecondenser,bringthein?uencetheresults.Cross-sectionalareasintheseproductsmaybesubjecttoendgrainattackinnitricacid.Theproportionofendgrainintheacidtoaboilonthehotplate,andkeepboilingthroughoutthespecimenshouldthereforebekeptlowunlesssuchsurfaceisactuallytotestperiod(Note15).Aftereachtestperiod,rinsethespeci-beexposedinserviceinvolvingnitricacid.Inthislattercase,themenswithwaterandtreatbyscrubbingwithrubberoranylonproportionofendgraininthespecimenshouldbekepthigh.

brushunderrunningwatertoremoveanyadheringcorrosion33.2Wherefeasiblefortheproductform,grindalltheproducts,thendryandweighthem.Dryingmaybefacilitated,specimensurfacesusingCAMI/ANSI120[FEPA/ISOP120]ifdesired,bydippingthespecimensinacetoneaftertheyarepaper-backed,wetordry,closedcoatedabrasivepaper,withscrubbed.

waterasacoolant.Ifabrasivepaperisuseddry,polishslowly34.4(Warning—Ithasbeenreportedthatviolentboilingtoavoidoverheating.Donotuseabrasiveswithgrindingaids;resultinginacidspillscanoccur.Itisimportanttoensurethatsomegrindingaidscontain?uoridesthatcanaffectthetheconcentrationofaciddoesnotincreaseandthatanadequatemeasuredcorrosionrate.

numberofboilingchips(whichareresistanttoattackbythe33.3Removealltracesofoxidescaleandheattintformedtestsolution)arepresent.)

duringheattreatments.AnyscalethatcannotberemovedbyNOTE15—Takecaretopreventcontaminationofthetestingsolution,grinding(forexample,instampednumbers)mayberemovedespeciallyby?uorides,eitherbeforeorduringthetest.ExperiencehasbyusingoneofthepicklingsolutionsdescribedinPracticeshownthatthepresenceofevensmallamountsofhydro?uoricacidwillA380/A380M,TableA1.1.

increasethecorrosionrateinthenitricacidtest.Itisnotpermissible,forexample,toconductnitric-hydro?uoricacidtestsinthesamehoodwith33.4Measurethespecimen,includingtheinnersurfacesofnitricacidtests.

anyholestothenearest0.05mm(0.001in.),andcalculatethe34.5Thestandardtestconsistsof?veboilingperiodsoftotalexposedareaincm2.

48heachwithafreshtestsolutionbeingusedineachperiod.33.5Degreasethespecimenusingsuitablenonchlorinated34.5.1Acombinationofone48-hperiodandtwo96-hagents,suchassoapandlukewarmwater,oracetone(Note13).periods(notnecessarilyinthatorder)insteadof?ve48-htestDrythespecimensandweigheachonetothenearest0.001g.periodsmaybeusedifsoagreedbythepurchaser.Storethespecimensinadesiccatoruntilthetestistobeperformed.

35.CalculationandReport

N35.1Calculation—TheeffectoftheacidonthematerialOTE13—Thecleaningtreatmentdescribedmaybesupplementedbyimmersingthespecimeninnitricacid(forexample,20weight%at49toshallbemeasuredbydeterminingthelossofweightofthe60°C(120to140°F))for20min,followedbyrinsing,drying,andspecimenaftereachtestperiodandforthetotalofthetestweighing.Inthecaseofsmall-diametertubularspecimenswhichcannotperiods.UsingEq1,calculatethecorrosionrateforeachbeconvenientlyresurfacedontheinside,itisdesirabletoincludeinthespecimenforeachtestperiod,andforthetotalofthetestpreparationanimmersioninboilingnitricacid(65%)for2to4husingthesameapparatusasfortheactualtest.Thepurposeofthesetreatmentsperiods.

istoremoveanysurfacecontaminationthatmaynotbeaccomplishedby35.2Report—Reportthecalculatedcorrosionratesforthetheregularcleaningmethodandwhichmayincreasetheapparentweight

individualperiodsinchronologicalorder,aswellasthe

10

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averageforthe?vetestperiods.Ifthemodi?edtestperiods(34.5.1)areused,thenidentifyeachresultastothesequenceandlengthofthetestperiod.36.PrecisionandBias

36.1Precision—TheprecisionofPracticeCisbeingdeter-mined.

36.2Bias—Thispracticehasnobiasbecausetheresistancetointergranularcorrosionisde?nedonlyintermsofthispractice.

PRACTICEE—COPPER-COPPERSULFATE–16%

SULFURICACIDTESTFORDETECTINGSUSCEPTIBILITYTOINTERGRANULAR

ATTACKINAUSTENITICSTAINLESSSTEELS(4,5)37.Scope

37.1Thispracticedescribestheprocedurebywhichthecopper–coppersulfate–16%sulfuricacidtestisconductedtodeterminethesusceptibilityofausteniticstainlesssteelstointergranularattack.Thepresenceorabsenceofintergranularcorrosioninthistestisnotnecessarilyameasureoftheperformanceofthematerialinothercorrosivemedia.Thetestdoesnotprovideabasisforpredictingresistancetootherformsofcorrosion,suchasgeneralcorrosion,pitting,orstress-corrosioncracking.38.RapidScreeningTest

38.1Beforetestinginthecopper–coppersulfate–16%sul-furicacidtest,specimensofcertaingradesofstainlesssteel(seeTable4)maybegivenarapidscreeningtestinaccordancewiththeproceduresgiveninPracticeA(Sections4through13).Preparation,etching,andtheclassi?cationofetchstruc-turesaredescribedtherein.Theuseofetch-structureevalua-tionsinconnectionwiththecopper–coppersulfate–16%sulfuricacidtestisspeci?edinTable4.

38.1.1CorrosiontestspecimenshavingacceptableetchstructuresintheOxalicAcidEtchTestwillbeessentiallyfreeofintergranularattackinthecopper–coppersulfate–16%sulfuricacidtest.Suchspecimensareacceptablewithout

TABLE4UseofEtchStructureClassi?cationsfromtheOxalicAcidEtchTestwiththeCopper–CopperSulfate–16%Sulfuric

AcidTest

GradeAISIAISIAISIAISIAISIAISIAISIAISIAISIAISIAISIAISIAISI

Atestinginthecopper–coppersulfate–16%sulfuricacidtest.Allspecimenshavingsuspectetchstructuresmustbetestedinthecopper–coppersulfate–16%sulfuricacidtest.

38.1.2Heattreatthematerialwhenrequiredbyandinaccordancewith43.3.1priortoperformingtheetchtest.39.SummaryofPractice

39.1Asuitablesampleofanausteniticstainlesssteel,embeddedincoppershotorgrindings,isexposedtoboilingacidi?edcoppersulfatesolutionfor15h.Afterexposureintheboilingsolution,thespecimenisbent.Intergranularcrackingorcrazingisevidenceofsusceptibility.

39.2AlternativeTestingProcedures:

39.2.1Unlessprohibitedbythepurchaserinthepurchaseorder,thesupplierispermittedtomeettherequirementsofPracticeEbyperformingatestinaccordancewithISO3651–2,MethodA,providedthatthetestingperiodshallbeaminimumof15h.Whenasensitizationtreatmentisrequired,sensitizationheattreatmentT1[700°C610°C(1292°F618°F),30min,waterquench]shallbeusedunlessthesupplierandpurchasershallagreeuponpreparationofweldedtestpiecestobetestedintheas-weldedcondition.39.2.2Whenthisalternativetestprocedureisused,itshallbenotedonthetestreport.40.Apparatus

40.1ThebasicapparatusisdescribedinSection18.40.2SpecimenSupports—Anopenglasscradlecapableofsupportingthespecimensandcoppershotorgrindingsinthe?askisrecommended.

NOTE16—Itmaybenecessarytoembedlargespecimens,suchasfromheavybarstock,incoppershotonthebottomofthetest?ask.Acoppercradlemayalsobeused.

40.3HeatSource—Anygasorelectricallyheatedhotplatemaybeutilizedforheatingthetestsolutionandkeepingitboilingthroughoutthetestperiod.

41.Acidi?edCopperSulfateTestSolution

41.1Dissolve100gofreagentgradecoppersulfate(CuSO4·5H2O)in700mLofdistilledwater,add100mLofsulfuricacid(H2SO4,cp,spgr1.84),anddiluteto1000mLwithdistilledwater.

NOTE17—Thesolutionwillcontainapproximately6weight%ofanhydrousCuSO4and16weight%ofH2SO4.

AcceptableEtchStructuresStep,Step,Step,Step,Step,Step,Step,Step,Step,Step,Step,Step,Step,

dual,dual,dual,dual,dual,dual,dual,dual,dual,dual,dual,dual,dual,

endendendendendendendendendendendendend

graingraingraingraingraingraingraingraingraingraingraingraingrain

IIIIIIIIIIIIIandandandandandandandandandandandandand

IIIIIIIIIIIIIIIIIIIIIIIIII

SuspectEtchStructuresADitchDitchDitchDitchDitchDitchDitchDitchDitchDitchDitchDitchDitch

201202301304304L304H316316L316H317317L321347

42.CopperAddition

42.1Electrolyticgradecoppershotorgrindingsmaybeused.Shotispreferredforitseaseofhandlingbeforeandafterthetest.

42.2Asufficientquantityofcoppershotorgrindingsistobeusedtocoverallsurfacesofthespecimenwhetheritisinaventedglasscradleorembeddedinalayerofcoppershotonthebottomofthetest?ask.

42.3Theamountofcopperused,assuminganexcessofmetalliccopperispresent,isnotcritical.Theeffectivegalvaniccouplingbetweencopperandthetestspecimenmayhaveimportance(6).

11

Specimenshavingthesestructuresmustbetestedinthecopper–coppersulfate–16%sulfuricacidtest.

--`,`,``,``,`,,`,,,,,,```,`,,```-`-`,,`,,`,`,,`---

A262?15

42.4Thecoppershotorgrindingsmaybereusediftheyare1hat675°C.Careshouldbetakentoavoidcarburizingorcleanedinwarmtapwateraftereachtest.nitridingthespecimens.Theheattreatingisbestcarriedoutin43.SpecimenPreparation

airorneutralsalt.

43.1ThesizeofthesamplesubmittedfortestandtheareaNOTE18—Thesensitizingtreatment675°Cisperformedtochecktheeffectivenessofstabilizedand0.03%maximumcarbonmaterialsinfromwhichitistobetaken(endormiddleofcoil,midwayresistingcarbideprecipitation,hence,intergranularattack.

surfaceandcenter,andsoforth)isgenerallyspeci?edintheagreementbetweenthepurchaserandtheseller.Thetesting44.TestConditions

apparatusdictatesthe?nalsizeandshapeofthetestspecimen.44.1Thevolumeofacidi?edcoppersulfatetestsolutionThespecimencon?gurationshouldpermiteasyentranceandusedshouldbesufficienttocompletelyimmersethespecimensremovalthroughtheneckofthetestcontainer.

andprovideaminimumof8mL/cm2(50mL/in.2)ofspecimen43.1.1Table5maybeusedasaguidetodeterminesurfacearea.

acceptablespecimensizes.Theremayberestrictionsplacedon44.1.1Asmanyasthreespecimenscanbetestedinthesamespecimensizebythetestingapparatus.

container.Itisidealtohaveallthespecimensinone?asktobe43.1.2Specimensobtainedbyshearingshouldhavetheofthesamegrade,butitisnotabsolutelynecessary.Theshearededgesmachinedorgroundoffpriortotesting.Caresolutionvolume-to-samplearearatioistobemaintained.shouldbetakenwhengrindingtoavoidoverheatingor44.1.2Thetestspecimen(s)shouldbeimmersedinambient“burning.”A“squared”edgeisdesirable.

testsolution,whichisthenbroughttoaboilandmaintained43.2Anyscaleonthespecimensshouldberemovedme-boilingthroughoutthetestperiod.Begintimingthetestperiodchanicallyunlessaparticularsurface?nishistobeevaluated.whenthesolutionreachestheboilingpoint.

Chemicalremovalofscaleispermissiblewhenthisisthecase.NOTE19—MeasuresshouldbetakentominimizebumpingoftheMechanicalremovalofscaleshouldbeaccomplishedwithsolutionwhenglasscradlesareusedtosupportspecimens.Asmall120-gritiron-freealuminumoxideabrasive.

amountofcoppershot(eighttotenpieces)onthebottomofthe?askwill43.2.1Eachspecimenshouldbedegreasedusingacleaningconvenientlyservethispurpose.

solventsuchasacetone,alcohol,ether,oravapordegreaser44.1.3Thetimeofthetestshallbeaminimumof15h,priortobeingtested.

unlessalongertimeisagreeduponbetweenthepurchaserand43.3Allausteniticmaterialinthe“as-received”(mill-theproducer.Ifnot15h,thetesttimeshallbespeci?edontheannealed)conditionshouldbecapableofmeetingthistest.testreport.Freshtestsolutionwouldnotbeneededifthetest43.3.1Specimensofextra-low-carbonandstabilizedgradesweretorun48oreven72h.(Ifanyadherentcopperremainsaretestedaftersensitizingheattreatmentsat650to675°Conthespecimen,itmayberemovedbyabriefimmersionin(1200to1250°F),whichistherangeofmaximumcarbideconcentratednitricacidatroomtemperature.)

precipitation.Themostcommonlyusedsensitizingtreatmentis

NOTE20—Resultsintheliteratureindicatethatthistestismoresensitiveifitisrunforlongertimes(3,7).

TABLE5SizesofTestSpecimens

45.BendTest

TypeofMaterial

SizeofTestSpecimen

45.1Thetestspecimenshallbebentthrough180°andoverWroughtwireorrod:

adiameterequaltothethicknessofthespecimenbeingbentUpto6mm(?in.)indiameter,inclFulldiameterby75mm(3in.)(min)long

(seeFig.10).Innocaseshallthespecimenbebentovera

Over6mm(?in.)indiameter

Cylindricalsegment6mm(?in.)thickby25mm(1in.)(max)wideby75to125mm(3to5in.)longAWroughtsheet,strip,plates,or?atrolledproducts:

Upto5mm(3?16in.)thick,incl

Fullthicknessby9to25mm(\to1in.)wideby75mm(3in.)(min)long

Over5mm(3?16in.)thick

5to13mm(3?16to?in.)thickby9to25mm(\to1in.)wideby75mm(3in.)(min)longBTubing:

Upto38mm(1?in.)indiameter,inclFullring,25mm(1in.)wideCOver38mm(1?in.)indiameterAcircumferentialsegment75mm

(3in.)(min)longcutfroma25mm(1-in.)wideringDAWhenbendingsuchspecimens,thecurvedsurfaceshallbeontheoutsideofthebend.BOnesurfaceshallbeanoriginalsurfaceofthematerialundertestanditshallbeontheoutsideofthebend.Cold-rolledstriporsheetsmaybetestedinthethicknesssupplied.CRingsectionsarenot?attenedorsubjectedtoanymechanicalworkbeforetheyaresubjectedtothetestsolution.DSpecimensfromweldedtubesover38mm(1?in.)indiametershallbetakenwiththeweldontheaxisofthebend.

FIG.10ABentCopper–CopperSulfate–SulfuricAcid

TestSpecimen

12

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