2024年3月19日发(作者：綦颖然)

Designation:A262

−

15

StandardPracticesfor

DetectingSusceptibilitytoIntergranularAttackinAustenitic

StainlessSteels

1

ThisstandardisissuedunderthefixeddesignationA262;thenumberimmediatelyfollowingthedesignationindicatestheyearof

originaladoptionor,inthecaseofrevision,rinparenthesesindicatestheyearoflastreapproval.A

superscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.

mentofDefense.

*

1.1Thesepracticescoverthefollowingfivetests:

1.1.1PracticeA—OxalicAcidEtchTestforClassification

ofEtchStructuresofAusteniticStainlessSteels(Sections4to

13,inclusive),

1.1.2Practice

B—FerricSulfate-SulfuricAcidTestforDe-

tectingSusceptibilitytoIntergranularAttackinAustenitic

StainlessSteels(Sections14to25,inclusive),

1.1.3Practice

C—NitricAcidTestforDetectingSuscepti-

bilitytoIntergranularAttackinAusteniticStainlessSteels

(Sections26to36,inclusive),

1.1.4Practice

E—Copper–CopperSulfate–SulfuricAcid

TestforDetectingSusceptibilitytoIntergranularAttackin

AusteniticStainlessSteels(Sections37to46,inclusive),and

1.1.5Practice

F—Copper–CopperSulfate–50%Sulfuric

AcidTestforDetectingSusceptibilitytoIntergranularAttack

inMolybdenum-BearingAusteniticStainlessSteels(Sections

47to58,inclusive).

1.2

TheOxalicAcidEtchTestisarapidmethodof

identifying,bysimpleetching,thosespecimensofcertain

stainlesssteelgradesthatareessentiallyfreeofsusceptibility

tointergranularattackassociatedwithchromiumcarbide

pecimenswillhavelowcorrosionratesin

certaincorrosiontestsandthereforecanbeeliminated

(screened)fromtestingas“acceptable.”Theetchtestis

applicableonlytothosegradeslistedintheindividualhotacid

testsandclassifiesthespecimenseitheras“acceptable”oras

“suspect.”

1.3Theferricsulfate-sulfuricacidtest,thecopper–copper

sulfate–50%sulfuricacidtest,andthenitricacidtestarebased

onweightlossdeterminationsand,thus,provideaquantitative

contrast,thecopper–coppersulfate–16%sulfuricacidtestis

basedonvisualexaminationofbendspecimensand,therefore,

classifiesthespecimensonlyasacceptableornonacceptable.

1.4Thepresenceorabsenceofintergranularattackinthese

testsisnotnecessarilyameasureoftheperformanceofthe

estsdonot

provideabasisforpredictingresistancetoformsofcorrosion

otherthanintergranular,suchasgeneralcorrosion,pitting,or

stress-corrosioncracking.

N

OTE

1—SeeAppendixX1forinformationregardingtestselection.

1.5ThevaluesstatedinSIunitsaretoberegardedas

h-poundequivalentsareinparenthesesand

maybeapproximate.

1.6Thisstandarddoesnotpurporttoaddressallofthe

safetyconcerns,ifany,e

responsibilityoftheuserofthisstandardtoestablishappro-

priatesafetyandhealthpracticesanddeterminetheapplica-

ecific

hazardsstatementsaregivenin10.1,20.1.1,20.1.9,31.3,34.4,

53.1.1,and53.1.10.

2.

ReferencedDocuments

2.1ASTMStandards:

2

A370TestMethodsandDefinitionsforMechanicalTesting

ofSteelProducts

A380/A380MPracticeforCleaning,Descaling,andPassi-

vationofStainlessSteelParts,Equipment,andSystems

D1193SpecificationforReagentWater

E3GuideforPreparationofMetallographicSpecimens

2.2ASMECode:

3

ASMEBoiler&PressureVesselCode,SectionIX

2.3ACSSpecifications:

4

ReagentChemicals,SpecificationsandProcedures

ForreferencedASTMstandards,visittheASTMwebsite,,or

contactASTMCustomerServiceatservice@ualBookofASTM

Standardsvolumeinformation,refertothestandard’sDocumentSummarypageon

theASTMwebsite.

3

AvailablefromAmericanSocietyofMechanicalEngineers(ASME),ASME

InternationalHeadquarters,TwoParkAve.,NewYork,NY10016-5990,

.

4

AvailablefromAmericanChemicalSociety(ACS),1155SixteenthStreet,NW,

Washington,DC20036,

2

ThesepracticesareunderthejurisdictionofASTMCommitteeA01onSteel,

StainlessSteelandRelatedAlloysandarethedirectresponsibilityofSubcommittee

A01.14onMethodsofCorrosionTesting.

CurrenteditionapprovedSept.1,ally

eviouseditionapprovedin2014asA262–:

10.1520/A0262-15.

1

*ASummaryofChangessectionappearsattheendofthisstandard

Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,States

1

A262−15

2.4ISOStandard:

5

ISO3651-2DeterminationofResistancetoIntergranular

CorrosionofStainlessSteels—Part2:Ferritic,Austenitic,

andFerritic-Austenitic(Duplex)StainlessSteels—

CorrosionTestinMediaContainingSulfuricAcid

ofReagents

3.1PurityofReagents—Reagentgradechemicalsshallbe

otherwiseindicated,itisintendedthat

allreagentsconformtothespecificationsoftheCommitteeon

AnalyticalReagentsoftheAmericanChemicalSociety

6

where

suchspecifiradesmaybeused,

provideditisfirstascertainedthatthereagentisofsufficiently

highpuritytopermititsusewithoutlesseningtheaccuracyof

thetestresult.

3.2PurityofWater—Unlessotherwiseindicated,references

towatershallbeunderstoodtomeanreagentwaterasdefined

byTypeIVofSpecificationD1193.

PRACTICEA—OXALICACIDETCHTESTFOR

CLASSIFICATIONOFETCHSTRUCTURESOF

AUSTENITICSTAINLESSSTEELS(

1)

7

4.1TheOxalicAcidEtchTestisusedforacceptanceof

wroughtorcastausteniticstainlesssteelmaterialbutnotfor

262PracticeAasastand-alone

testmayrejectmaterialthattheapplicablehotacidtestwould

findacceptable;suchuseisoutsidethescopeofthispractice.

4.2Thistestisintendedtobeusedinconnectionwithother

evaluationtestsdescribedinthesepracticestoprovidearapid

methodforidentifyingqualitativelythosespecimensthatare

certaintobefreeofsusceptibilitytorapidintergranularattack

ecimenshavelowcorrosionratesin

thevarioushotacidtestswhichrequirefrom15to240hof

pecimensareidentifiedbymeansoftheir

etchstructures,whichareclassifiedaccordingtothecriteria

giveninSection

11.

4.3TheOxalicAcidEtchTestmaybeusedtoscreen

specimensintendedfortestinginPracticeB—FerricSulfate-

SulfuricAcidTest,PracticeC—NitricAcidTest,Practice

E—Copper-CopperSulfate–16%SulfuricAcidTest,andPrac-

ticeF—Copper-CopperSulfate–50%SulfuricAcidTest.

4.4Eachoftheseotherpracticescontainsatableshowing

whichclassificationsofetchstructuresonagivenstainless

steelgradeareequivalenttoacceptableorsuspectperformance

enshavingacceptableetch

ens

havingsuspectetchstructuresmustbetestedinthespecified

hotacidsolution.

AvailablefromInternationalOrganizationforStandardization(ISO),1,

laVoie-Creuse,CP56,CH-1211Geneva20,Switzerland,.

6

ForsuggestionsonthetestingofreagentsnotlistedbytheAmericanChemical

Society,seeAnalarStandardsforLaboratoryChemicals,BDHLtd.,Poole,Dorset,

U.K.,andtheUnitedStatesPharmacopeiaandNationalFormulary,-

copeialConvention,Inc.(USPC),Rockville,MD.

7

Theboldfacenumbersinparenthesesrefertoalistofreferencesattheendof

thisstandard.

5

4.5Therearetwoclassesofspecimenstobeconsidered:

basemetal,andprocess-affectedmetal.

4.5.1Process-affectedmetalcontainsanyconditionthat

affectsthecorrosionpropertiesofthematerialinanon-uniform

way,suchas(butnotlimitedto)welds;ed,or

oxidizedsurfaces;mechanicaldeformation;andareasaffected

talhasnoneoftheseconditions.

4.5.2BecausePracticesB,C,andFinvolveimmersingthe

entirespecimenandaveragingthemasslossoverthetotal

specimenarea,andbecausewelding,carburization,mechanical

deformation,andthelikeaffectonlypartofaspecimen,the

presenceofprocess-affectedmetalinaspecimencanaffectthe

testresultinanunpredictablewaydependingonthepropor-

tionsoftheareaaffected.

4.5.3Ifthepresenceoftheseorotherlocalizedconditionsis

aconcerntothepurchaser,thenteststhatdonotaveragethe

masslossoverthetotalspecimensurfacearea,suchasPractice

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

Sulfate–SulfuricAcidTestforDetectingSusceptibilityto

IntergranularAttackinAusteniticStainlessSteels,shouldbe

considered.

yofPractice

5.1Aspecimenrepresentativeofthematerialtobeevalu-

atedispolishedtoaspecifiedfinishandover-etchedusing

hedspecimenisthen

hedstruc-

tureiscomparedwithreferencephotographstodetermine

tmaterial

isthensubjectedtothespecifiedhotacidimmersiontest.

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ficanceandUse

6.1Useoftheetchtestallowsrapidacceptanceofspecific

lotsofmaterialwithouttheneedtoperformtime-consuming

andcostlyhotacidimmersiontestsonthoselots.

tus

7.1EtchingCell:

7.1.1Anetchingcellmaybeassembledusingcomponents

atively,acommercial

electropolisher/etcher(asusedformetallographicsample

preparation)maybeusedforsmallspecimensprovidedthe

currentdensityrequirementof

10.2ismet.

7.1.2SourceofDirectCurrent—Battery,generator,orrec-

tifiercapableofsupplyingabout15Vand20A.

7.1.3Ammeter—Fordirectcurrent;usedtomeasurethe

currentonthespecimentobeetched.

7.1.4VariableResistance—Usedtocontrolthecurrenton

thespecimentobeetched.

7.1.5Cathode—Astainlesssteelcontainer,forexample,a

1-L(1-qt)stainlesssteelbeaker.

7.1.5.1AlternateCathode—Apieceofflatstainlesssteelat

leastaslargeasthespecimensurface.

7.1.6ElectricalClamp—Toholdthespecimentobeetched

andtocompletetheelectricalcircuitbetweenthespecimenand

thepowersourcesuchthatthespecimenistheanodeofthe

cell.

2

A262−15

7.1.7Thepowersource,resistor,andammetermustbesized

10.2.1.2Adjustthevariableresistanceuntiltheammeter

appropriatelyforprovidingandcontrollingthecurrentas

readinginamperesisequaltothetotalimmersedareaofthe

specifiedin10.2ofthispractice.

specimeninsquarecentimetres.

7.1.8Asdescribed,theelectrolytecontaineristhecathode;

itmaybeastainlesssteelbeakerorfabricatedfromstainless

10.3Ayellow-greenfilmisgraduallyformedonthecath-

steelsuchasbyweldingasectionoftubeorpipetoaflatplate

is

atively,theelectrolytecontainermaybeglass

occurs,removethefilmbyrinsingtheinsideofthestainless

(orothernon-conducting,corrosionresistingmaterial)inlieu

steelbeaker(orthesteelusedasthecathode)withanacidsuch

ofastainlesssteelcontainer,andthecathodemaybeaflatplate

as30%HNO

3

.

lattercase,theflat

10.4Thetemperatureoftheetchingsolutiongradually

surfaceofthecathodemustbeatleastaslargeas,facing,and

etemperaturebelow50°C.

approximatelycenteredon,thepreparedsurfaceofthespeci-

be

onfigurationsoftheelectrodesmightnotprovide

cooledintapwaterwhiletheotherisusedforetching.

ase,the

10.4.1Therateofheatingdependsonthetotalcurrent

sizeandshapeofthespecimendictatethesizeandconstruction

(ammeterreading)ore,keep

theareatobeetchedassmallaspossiblewhileatthesametime

overridingprincipleisthattheetchneedstobeuniformover

meetingtherequirementsofdesirableminimumareatobe

thesurfacetobeexamined.

etched.

7.2MetallurgicalMicroscope—Forexaminationofetched

10.5Avoidimmersingtheclampholdingthespecimenin

microstructuresat250to500diameters.

theetchingsolution.

tsandMaterials

10.6Rinsing—Followingetching,rinsethespecimenthor-

oughlyinhotwaterandtheninacetoneoralcoholtoavoid

8.1EtchingSolution(10%)—Dissolve100gofreagent

crystallizationofoxalicacidontheetchedsurfaceduring

gradeoxalicacidcrystals(H

2

C

2

O

4

·2H

2

O)in900mLof

drying.

tilallcrystalsaredissolved.

8.1.1AlternateEtchingSolution(See10.7)—Dissolve100g

10.7Itmaybedifficulttorevealthepresenceofstep

ofreagentgradeammoniumpersulfate((NH

structuresonsomespecimenscontainingmolybdenum(AISI

4

)

2

S

tildissolved.

2

O

8

)in

900

316,316L,317,317L),whicharefreeofchromiumcarbide

sensitization,

ngandTestSpecimens

cases,analternateelectrolyteofammoniumpersulfatemaybe

9.1Thespecifiedhotacidtestprovidesinstructionsfor

usedinplaceofoxalicacid.(See

8.1.1.)Anetchfor5or10

samplingandforspecimenpreparationsuchasasensitization

minat1A/cm

2

inasolutionatroomtemperaturereadily

onalinstructionsspecifictoPracticeA

developsstepstructuresonsuchspecimens.

follow:

ficationofEtchStructures

9.2Thepreferredspecimenisacross-sectionincludingthe

chfinishingof

11.1Examinetheetchedsurfaceonametallurgicalmicro-

theproductsurfaceshouldbeperformedasisrequiredto

scopeat250×to500×forwroughtsteelsandatabout250×for

removeforeignmaterial.

caststeels.

9.3Wheneverpractical,useacross-sectionalareaof1cm

2

11.2Examinetheetchedcross-sectionalareasthoroughly

ross-sectionaldimensionislessthan1cm,

bycompletetraversefrominsidetooutsidediametersofrods

thentheotherdimensionofthecross-sectionshouldbea

andtubes,fromfacetofaceonplates.

thdimensionsoftheproductare

11.2.1Microscopicalexaminationofaspecimenshallbe

lessthan1cm,useafullcrosssection.

madeonmetalunaffectedbycold-working,carburization,

welding,ftheseconditionsarefound,note

9.4Polishing—Onalltypesofmaterials,polishcrosssec-

theirpresenceinthereport.

tionalsurfacesthroughCAMI/ANSI600[FEPA/ISOP1200]in

accordancewithGuide

E3priortoetchingandexamination.

11.3Classifytheetchstructuresintothefollowingtypes

Notallscratchesneedtoberemoved.

(

Note2):

11.3.1StepStructure(Fig.1)—Stepsonlybetweengrains,

ure

noditchesatgrainboundaries.

10.1(Warning—Etchingshouldbecarriedoutundera

11.3.2DualStructure(Fig.2)—Someditchesatgrain

,whichisrapidlyevolvedattheelectrodes

boundariesinadditiontosteps,butnosinglegraincompletely

withsomeentrainmentofoxalicacid,ispoisonousand

surroundedbyditches.

irritatingtomucousmembranes.)

11.3.3DitchStructure(

Fig.3)—Oneormoregrainscom-

pletelysurroundedbyditches.

10.2Etchthepolishedspecimenat1A/cm

2

for1.5min.

11.3.4IsolatedFerrite(Fig.4)—Observedincastingsand

10.2.1Toobtainthecorrectspecifiedcurrentdensity:

etweenaustenitematrixandferritepools.

10.2.1.1Measurethetotalimmersedareaofthespecimento

11.3.5InterdendriticDitches(

Fig.5)—Observedincastings

beetchedinsquarecentimetres.

terconnectedditches.

3

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A262−15

FIG.2DualStructure(250×)(SomeDitchesatGrainBoundaries

inAdditiontoSteps,butNoOneGrainCompletelySurrounded)

FIG.4IsolatedFerritePools(250×)(ObservedinCastingsand

etweenAusteniteMatrixandFerritePools)

11.3.6End-GrainPittingI(Fig.6)—Structurecontainsa

fewdeepend-grainpitsalongwithsomeshallowetchpitsat

500×.(Ofimportanceonlywhenthenitricacidtestisused.)

11.3.7End-GrainPittingII(Fig.7)—Structurecontains

numerous,deepend-grainpitsat500×.(Ofimportanceonly

whennitricacidtestisused.)

N

OTE

2—Allphotomicrographsweremadewithspecimensthatwere

etchedunderstandardconditions:10%oxalicacid,roomtemperature,

1.5minat1A/cm

2

.

11.4Theevaluationofetchstructurescontainingonlysteps

andofthoseshowinggrainscompletelysurroundedbyditches

ineveryfisthat

appeartobedualstructures,moreextensiveexaminationis

requiredtodetermineifthereareanygrainscompletely

circledgrainisfound,classifythesteelasa

ditchstructure.

11.4.1Onstainlesssteelcastings(alsoonweldmetal),the

stepsbetweengrainsformedbyelectrolyticoxalicacidetching

tendtobelessprominentthanthoseonwroughtmaterialsor

4

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FIG.1StepStructure(500×)(StepsBetweenGrains,NoDitches

atGrainBoundaries)

FIG.3DitchStructure(500×)(OneorMoreGrainsCompletely

SurroundedbyDitches)

A262−15

FIG.5InterdendriticDitches(250×)(ObservedinCastingsand

terconnectedDitches)

N

OTE

1—Thisoragreaterconcentrationofendgrainpitsat500×(using

standardetchingconditions)indicatesthatthespecimenmustbetested

whenscreeningisfornitricacidtest.

FIG.7EndGrainPittingII(500×)

structures,specimenshavingasmuchormoreendgrainpitting

thanthatshownin

Fig.7cannotbesafelyassumedtohavelow

nitricacidratesandshouldbesubjectedtothenitricacidtest

wheneveritisspecifiarp,deeppitsshouldnotbe

confusedwiththeshallowpitsshownin

Figs.1and6.

tchStructureClassifications

12.1Theuseoftheseclassificationsdependsonthehotacid

corrosiontestforwhichstainlesssteelspecimensarebeing

screenedbyetchinginoxalicacidandisdescribedineachof

thepractices.

ionandBias

13.1PrecisionandBias—Noinformationispresentedabout

eithertheprecisionorbiasofPracticeA—OxalicAcidEtch

TestforclassificationofEtchStructuresofAusteniticStainless

Steelssincethetestresultisnonquantitative.

N

OTE

1—Todifferentiatebetweenthetypesofpits,useamagnification

of500×swhichnow

appearcompletelyblackareendgrainpits.

FIG.6EndGrainPittingI(500×)(AFewDeepEndGrainPits

(See1inFigure)andShallowEtchPits(2))

PRACTICEB—FERRICSULFATE–SULFURIC

ACIDTESTFORDETECTINGSUSCEPTIBILITY

TOINTERGRANULARATTACKIN

AUSTENITICSTAINLESSSTEELS(

2)

14.1Thispracticedescribestheprocedureforconducting

theboiling120-hferricsulfate–50%sulfuricacidtestwhich

measuresthesusceptibilityofausteniticstainlesssteelsto

intergranularattack.

14.2Thepresenceorabsenceofintergranularattackinthis

testisnotnecessarilyameasureoftheperformanceofthe

tdoesnot

provideabasisforpredictingresistancetoformsofcorrosion

5

r,anysusceptibilitytointergranular

attackisreadilydetectedbypronouncedditches.

11.4.2Somewroughtspecimens,especiallyfrombarstock,

epitsaresharpand

sodeepthattheyappearblack(Fig.7)itispossiblethatthe

specimenmaybesusceptibletoendgrainattackinnitricacid

ore,eventhoughthegrainboundariesallhavestep

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

A262−15

otherthanintergranular,suchasgeneralcorrosion,pitting,or

stress-corrosioncracking.

yoftheFerricSulfate-SulfuricAcidPractice

B

15.1Aspecimenrepresentativeofthematerialtobeevalu-

atedisimmersedinaboilingsolutionofferricsulfateand

sulfuricacidforaspecifiultingmasslossis

convertedtoacorrosionrate,whichiscomparedtoaspecified

maximumvaluetodeterminewhetherthematerialhasthe

resistancetoattackexpectedofthegradeofmaterialbeing

tested.

ficanceandUse

16.1Theferricsulfate-sulfuricacidtestdetectssusceptibil-

itytointergranularattackassociatedprimarilywithchromium

carbideprecipitateinunstabilizedausteniticstainlesssteels,

andtointergranularattackassociatedwithsigmaphase.

16.2Thecorrosionpotentialoftheferricsulfate-sulfuric

acidtesthasbeenreportedas0.6Vversusastandardcalomel

electrode(SCE),ascomparedwith0.75to1.0VforPracticeC,

and0.1VforPracticesEandF.(

3)

N

OTE

3—Ahighercorrosionpotentialindicatesmoreseverelyoxidizing

conditions.

17.3Ignore“process-affected”areas(seeSection

21);ap-

plicationoftheferricsulfate-sulfuricacidtesttoprocess-

affectedareasiscurrentlyoutsidethescopeofPracticeB.

17.4Corrosiontestspecimenshavingacceptableetchstruc-

turesintheOxalicAcidEtchTestwillbeessentiallyfreeof

specimensareacceptablewithouttestingintheferricsulfate-

cimenshavingsuspectetchstructures

shallbetestedintheferricsulfate-sulfuricacidtest.

tus

18.1Theapparatusisillustratedin

Fig.8.

N

OTE

4—Othergroundglassjoints,suchasthe45/40jointmayalsobe

used.

creeningTest

17.1Beforetestingintheferricsulfate-sulfuricacidtest,

specimensofcertaingradesofstainlesssteels(seeTable1)

maybegivenarapidscreeningtestinaccordancewith

proceduresgiveninPracticeA,OxalicAcidEtchTestfor

ClassificationofEtchStructuresofAusteniticStainlessSteels.

Preparation,etching,andtheclassificationofetchstructures

ofetchstructureevaluationsin

connectionwiththeferricsulfate-sulfuricacidtestisspecified

in

Table1.

17.2Heattreatthematerialinaccordancewith22.1priorto

performingtheetchtest.

18.1.1AnAllihncondenserwithaminimumoffourbulbs

andwithagroundglassjointtomatchthatoftheflask.

18.1.1.1Substitutionsforthiscondenserorflaskarenot

fically,thecold-fingertypeofcondenserwith

standardErlenmeyerflionrates

obtainedusingthecold-fingertypeofcondenserarelowerthan

thoseobtainedusingtheAllihntypeofcondenserwhetherdue

tolossofvaporortohigheroxygencontentinthesolutionor

wercorrosionratesleadtoacceptanceofmaterial

thatshouldberejected.

18.1.2A1-LErlenmeyerflaskwithagroundglassjointto

flaskopeninglimitsthesize

ofthespecimen;alargeropeningisdesirable.

TABLE1UseofEtchStructureClassificationsfromtheOxalic

AcidEtchTestwithFerricSulfate-SulfuricAcidTest

A

Grade

304

304L

316

316L

317

317L

CF-3

CF-8

CF-3M

CF-8M

A

AcceptableEtch

Structures

Step,

Step,

Step,

Step,

Step,

Step,

Step,

Step,

Step,

Step,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

endgrain,I&II

endgrain,I&II

endgrain,I&II

endgrain,I&II

endgrain,I&II

endgrain,I&II

isolatedferritepools

isolatedferritepools

isolatedferritepools

isolatedferritepools

Suspect

EtchStructures

B

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch,

Ditch,

Ditch,

Ditch,

interdendritic

interdendritic

interdendritic

interdendritic

ditches

ditches

ditches

ditches

GradesnotlistedinthistableeitherhavenotbeenevaluatedforuseofPractice

AwithPracticeBorhavebeenfoundtogiveacceptableresultsintheetchtest

attercasePracticesAwould

passmaterialthatshouldhavebeensubjectedtotheferricsulfate-sulfuricacid

test.

B

Specimenshavingthesestructuresshallbetestedintheferricsulfate-sulfuric

acidtest.

FIG.8ApparatusforFerricSulfate-SulfuricAcidTest

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

6

A262−15

18.1.3Glasscradle(Note5)—Canbesuppliedbyaglass-

containsanyconditionthataffectsthecorrosionpropertiesof

besizedsoastofit,withthespecimen,

thematerialinanon-uniformway,suchas(butnotlimitedto)

throughtheflbedesignedtoallowfree

welds;ed,oroxidizedsurfaces;mechanical

flowofthetestingsolutionaroundthespecimen.

deformation;talhasnone

N

OTE

5—Otherequivalentmeansofspecimensupport,suchasglass

oftheseconditions.

hooksorstirrups,mayalsobeused.

21.1.2ThePracticeBtestinvolvesimmersingtheentire

18.1.4BoilingChips—Usedtopreventbumping.

specimenandaveragingthemasslossovertheentiresurfaceof

18.1.5HighVacuumSiliconeGrease—Forthegroundglass

g,carburization,mechanicaldeformation,

joint.

andthelike,affectonlypartofaspecimen.

18.1.6Hotplate,capableofprovidingheatforcontinuous

21.1.3Themasslossratefromprocess-affectedmetalis

boilingofthesolution.

expectedtodifferfromthatfrombasemetal;thepresenceof

18.1.7Ananalyticalbalancecapableofweighingtothe

process-affectedmetalinaspecimenwillaffectthecalculated

nearest0.001g.

testresultinanunpredictableway.

21.1.4Ifthepresenceoftheseorotherlocalizedconditions

N

OTE

6—Duringtesting,thereissomedepositionofironoxidesonthe

upperpartoftheErlenmeyerflnbereadilyremoved,aftertest

isaconcerntothepurchaser,thenteststhatdonotaveragethe

completion,byboilingasolutionof10%hydrochloricacidintheflask.

masslossoverthetotalspecimensurfacearea,suchasPractice

18.1.8Desiccator—Forstorageofpreparedspecimensprior

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

totesting.

Sulfate–16%SulfuricAcidTestforDetectingSusceptibilityto

IntergranularAttackinAusteniticStainlessSteels,shouldbe

tsandMaterials

softhetestandacceptancecriteriashallbe

19.1FerricSulfateHydrate(Fe

asagreedbythepurchaserandproducer.

(SO

2

(SO

4

)

3

·xH

2

O),about75%

(Fe

24

)

21.2Unlessotherwisespecifiedbythepurchaser,thepro-

Ferric

3

)bymass.

19.1.1sulfateisaspecificadditivethatestablishes

ceduresforobtainingrepresentativebasemetalsamples,for

tutionsarenot

removingthespecimensfromthesamples,andthenumberof

permitted.

specimensshallbeatthediscretionoftheproducer.

19.2SulfuricAcid(H

2

(SO)

4

),95.0to98.0%bymass.

ationofTestSpecimens

Sulfate-SulfuricAcidTestSolution

22.1Heattreatextra-lowcarbonandstabilizedgradesat

20.1Prepare600mLof50%(49.4to50.9%)solutionas

650to675°C(1200to1250°F),whichistherangeof

follows:

maximumcarbideprecipitation,gthof

20.1.1(Warning—Protecttheeyesanduserubbergloves

timeofheating,andthemethodofsubsequentcoolingusedfor

hetestflaskunderahood.)

thissensitizingtreatmenttogetherwiththecorresponding

20.1.2First,measure400.0mLofTypeIVreagentwater

maximumpermissiblecorrosionrateshallbeasagreedbe-

andpourintotheErlenmeyerflask.

tweenthematerialproducerandpurchaser.

20.1.3Thenmeasure236.0mLofreagent-gradesulfuric

N

OTE

8—Themostcommonlyusedsensitizingtreatmentis1hat

acidslowlyandwithconstantstirringtothe

675°C(1250°F).

waterintheErlenmeyerflasktoavoidboilingbytheheat

evolved.

22.2Prepare

2

thespecimens,eachhavingatotalsurfacearea

of5to20cm.

N

OTE

7—Lossofvaporresultsinconcentrationoftheacid.

22.3Wherefeasiblefortheproductform,grindallthe

20.1.4Weigh25gofreagent-gradeferricsulfatetothe

specimensurfacesusingCAMI/ANSI120[FEPA/ISOP120]

nearest0.1gandaddtothesulfuricacidsolution.

paper-backed,wetordry,closedcoatedabrasivepaper,with

20.1.5Dropboilingchipsintotheflask.

sivepaperisuseddry,polishslowly

20.1.6Lubricategroundglassjointwithsiliconegrease.

seabrasiveswithgrindingaids;

20.1.7Coverflaskwithcondenserandcirculatecooling

somegrindingaidscontainfluoridesthatcanaffectthe

water.

measuredcorrosionrate.

20.1.8Boilthesolutionuntilallferricsulfateisdissolved

(seeNote7).

22.4Removealltracesofoxidescaleandheattintformed

20.1.9(Warning—Ithasbeenreportedthatviolentboiling

lethatcannotberemovedby

portanttoensurethat

grinding(forexample,instampednumbers)mayberemoved

theconcentrationofaciddoesnotincreaseandthatanadequate

byusingoneofthepicklingsolutionsdescribedinPractice

numberofboilingchips(whichareresistanttoattackbythe

A380/A380M,TableA1.1.(Residualoxidescalecausesgal-

testsolution)arepresent.)

vanicactionandconsequentactivationinthetestsolution.)

22.5Measurethespecimens,includingtheinnersurfacesof

ng

anyholes,tothenearest0.05mm(0.001in.)andcalculatethe

21.1Obtainandprepareonlybasemetalsamples.

totalexposedarea.

21.1.1Therearetwoclassesofspecimenstobeconsidered:

22.6Degreasethespecimensusingsuitablenonchlorinated

basemetal,s-affectedmetal

agents,suchassoapandlukewarmwater,

7

-

-

-

`

,

,

`

,

`

,

,

`

,

,

`

-

`

-

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`

`

,

,

`

,

`

`

`

,

,

,

,

,

,

`

,

,

`

,

`

`

,

`

`

,

`

,

`

-

-

A262−15

he

specimensinadesiccatoruntilthetestistobeperformed.

ure

23.1Ifthetestsolutionisnotalreadyboiling,bringitto

boiling.

23.1.1Keeptheflaskcoveredwiththecondenser(with

coolingwaterflowing)exceptwheninsertingorremoving

specimens.(SeeNote7.)

23.2Turnofftheheatsourceandallowtheboilingto

subside.

23.3Placespecimensinglasscradles.

23.4Uncovertheflask.

23.5Insertthespecimens.

23.6Replacethecondenserimmediately,restorecooling

waterflow,andturnontheheatsource.

23.7Marktheliquidlevelontheflasktoprovideacheckon

vaporloss,

thereisanappreciablechangeinthelevel,repeatthetestwith

freshsolutionandregroundandreweighedspecimens.

23.8Continuetheimmersionofthespecimensforatotalof

120h(fivedays),thenremovethespecimens,rinseinwateror

acetone,anddry.

23.9Weighthespecimensandsubtractthenewweights

fromoriginalweights.

r,if

preliminaryresultsaredesired,thespecimenscanberemoved

atanytimeforweighing.

23.11Changestothesolutionduringthe120-htestperiods

arenotnecessary.

23.12Ifthecorrosionrateisextraordinarilyhigh,asevi-

dencedbyachangeinthecolor(fromyellowtogreen)ofthe

solution,additionalferricsulfateinhibitormayneedtobe

otalweightlossofallthe

specimensinaflaskexceeds2g,moreferricsulfatemustbe

added.(Duringthetest,ferricsulfateisconsumedatarateof

10gforeach1gofdissolvedstainlesssteel.)

number(3or4)islimitedonlybythenumberofglasscradles

thatcanbefittedintotheflask.

ationandReport

24.1Theeffectoftheacidsolutiononthematerialis

measuredbydeterminingthelossofweightofthespecimen.

Thecorrosionratesshouldbereportedasmillimetresof

penetrationpermonth(

Note9),calculatedasfollows:

Millimetrepermonth5

~

73053W

!

/

~

A3t3d

!

(1)

forchromium-nickelsteels,d=7.9g/cm

3

forchromium-nickel-molybdenumsteels,d=8.00g/cm

3

N

OTE

9—Conversionfactorstoothercommonlyusedunitsforcorro-

sionratesareasfollows:

Millimetrespermonth×0.04=inchespermonth

Millimetrespermonth×0.47=inchesperyear

Millimetrespermonth×12=millimetresperyear

Millimetrespermonth×472=milsperyear

Millimetrespermonth×1000×density/3=milligramspersquare

decimetreperday

Millimetrespermonth×1.39×density=gramspersquaremetreperhour

ionandBias

25.1Precision—TheprecisionofPracticeBisbeingdeter-

mined.

25.2Bias—Thispracticehasnobiasbecausetheresistance

tointergranularcorrosionisdefinedonlyintermsofthis

practice.

PRACTICEC—NITRICACIDTESTFOR

DETECTINGSUSCEPTIBILITYTO

INTERGRANULARATTACKIN

AUSTENITICSTAINLESSSTEELS

26.1Thispracticedescribestheprocedureforconducting

theboilingnitricacidtest(

2)asemployedtomeasurethe

relativesusceptibilityofausteniticstainlesssteelstointer-

granularattack.

26.2Thepresenceorabsenceofintergranularattackinthis

testisnotnecessarilyameasureoftheperformanceofthe

materialinothercorrosiveenvironments;inparticular,itdoes

notprovideabasisforpredictingresistancetoformsof

corrosionotherthanintergranular,suchasgeneralcorrosion,

pitting,orstress-corrosioncracking.

yofTestMethodC,theNitricAcidTest

27.1Aspecimenrepresentativeofthematerialtobeevalu-

atedisimmersedinaboilingsolutionofnitricacidfora

specifiultingmasslossisconvertedtoa

corrosionrate,whichiscomparedtoaspecifiedmaximum

valuetodeterminewhetherthematerialhastheresistanceto

attackexpectedofthegradeofmaterialbeingtested.

ficanceandUse

28.1Thenitricacidtestdetectssusceptibilitytorapid

intergranularattackassociatedwithchromiumcarbideprecipi-

tate

28.2Thecorrosionpotentialofthenitricacidtest(Practice

C)hasbeenreportedas0.75to1.0Vversusastandardcalomel

electrodeascomparedwith0.6VforPracticeB,and0.1Vfor

PracticesEandF.(

3)

N

OTE

10—Highercorrosionpotentialindicatesmoreseverelyoxidizing

hcorrosionpotentialofthenitricacidtestsuggeststhat

itshouldbeinvokedonlywhenthematerialisdestinedfornitricacid

service.

where:

t=timeofexposure,h,

A=area,cm

2

,

W=weightloss,g,and

d=density,g/cm

3

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

creeningTest

29.1Beforetestinginthenitricacidtest,specimensof

certaingradesofstainlesssteel,asgiveninTable2,maybe

8

A262−15

TABLE2UseofEtchStructureClassificationfromOxalicAcid

EtchTestwithNitricAcidTest

A

Grade

AISI304

AISI304L

ACICF-8

ACICF-3

A

AcceptableEtch

Structures

Step,dual,endgrain

Step,dual,endgrain

Step,dual,isolatedferrite

Step,dual,isolatedferrite

I

I

pools

pools

SuspectEtch

Structures

B

Ditch,endgrainII

Ditch,endgrainII

Ditch,interdendriticditches

Ditch,interdendriticditches

30.3Heater—Ameansforheatingthetestsolutionsandof

trically

heatedhotplateissatisfactoryforthispurpose.

30.4Balance—Ananalyticalbalancecapableofweighing

toatleastthenearest0.001g.

30.5Desiccator—Forstorageofpreparedspecimensprior

totesting.

AcidTestSolution

31.1Thetestsolutionshallbe65.060.2weight%asnitric

aciddeterminedbyanalysis.

31.2Preparethissolutionbyaddingreagentgradenitric

acid(HNO

3

Table3)toreagentwaterattherateof108mLof

reagentwaterperlitreofreagentnitricacid.

31.3(Warning—Protecttheeyesanduserubberglovesfor

hetestflaskunderahood.)

31.4ThenitricacidusedshallconformtotheAmerican

ChemicalSocietySpecificationsforReagentChemicalsand

theadditionalrequirementsofthistestmethodasshownin

Table3.

ng

32.1Obtainandprepareonlybasemetalsamples.

32.1.1Therearetwoclassesofspecimenstobeconsidered:

basemetal,s-affectedmetal

containsanyconditionthataffectsthecorrosionpropertiesof

thematerialinanon-uniformway,suchas(butnotlimitedto)

welds;ed,oroxidizedsurfaces;mechanical

deformation;talhasnone

oftheseconditions.

32.1.2ThePracticeCtestinvolvesimmersingtheentire

specimenandaveragingthemasslossovertheentiresurfaceof

g,carburization,mechanicaldeformation,

andthelike,affectonlypartofaspecimen.

32.1.3Themasslossratefromprocess-affectedmetalis

expectedtodifferfromthatfrombasemetal;thepresenceof

process-affectedmetalinaspecimenwillaffectthecalculated

testresultinanunpredictableway.

32.1.4Ifthepresenceoftheseorotherlocalizedconditions

isaconcerntothepurchaser,thenteststhatdonotaveragethe

masslossoverthetotalspecimensurfacearea,suchasPractice

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

Sulfate–SulfuricAcidTestforDetectingSusceptibilityto

TABLE3NitricAcidCompositionLimits

Minimum

NitricAcid(HNO

3

),

masspercent

Ash,ppm

ChlorideasCl,ppm

Sulfate,as(SO

4

),ppm

Arsenic(As),ppm

Heavymetals,asPb,

ppm

Iron,(Fe),ppm

Additionallimitsper

PracticesA262

Fluorine(F),ppm

Phosphate(PO

4

),ppm

69.0

{

{

{

{

{

{

Maximum

71.0

5

0.5

1

0.01

0.2

0.2

GradesnotlistedinthistableeitherhavenotbeenevaluatedforuseofPractice

AwithPracticeBorhavebeenfoundtogiveacceptableresultsintheetchtest

attercasePracticeAwould

passmaterialthatshouldhavebeensubjectedtotheferricsulfate-sulfuricacid

test.

B

Specimenshavingthesestructuresshallbetestedinthenitricacidtest.

givenarapidscreeningtestinaccordancewithprocedures

giveninPracticeA,OxalicAcidEtchTestforClassificationof

ofthe

etchstructureevaluationsinconnectionwiththenitricacidtest

isspecifiedinTable2.

29.2Heattreatthematerialinaccordancewith33.1priorto

performingtheetchtest.

29.3Ignore“process-affected”areas,ifany(seeSection

32);applicationofthenitricacidtesttoprocess-affectedareas

iscurrentlyoutsidethescopeofPracticeC.

29.4Corrosiontestspecimenshavingacceptableetchstruc-

turesintheOxalicAcidEtchTestwillbeessentiallyfreeof

intergranularattackinthenitricacidtest;suchspecimensare

cimens

havingsuspectetchstructuresshallbetestedinthenitricacid

test.

tus

30.1Container—A1-LErlenmeyerflaskequippedwitha

coldfinger-typecondenser,asillustratedin

Fig.9.

30.2SpecimenSupports—Glasshooks,stirrups,orcradles

forsupportingthespecimensintheflaskfullyimmersedatall

timesduringthetestandsodesignedthatspecimenstestedin

thesamecontainerdonotcomeincontactwitheachother.

{

{

1

0.2

FIG.9FlaskandCondenserforNitricAcidTest

9

-

-

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,

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,

`

`

,

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`

,

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,

,

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,

,

,

,

,

,

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`

`

,

`

,

,

`

`

`

-

`

-

`

,

,

`

,

,

`

,

`

,

,

`

-

-

-

A262−15

IntergranularAttackinAusteniticStainlessSteels,shouldbe

lossofthespecimenduringtheearlypartofthetest.

softhetestandacceptancecriteriashallbe

asagreedbythepurchaserandproducer.

33.6Thestandardtestistotestonlyonespecimenofeach

r,incaseofdispute,theuse

32.2Unlessotherwisespecifiedbythepurchaser,thepro-

ofatleasttwospecimensforcheckpurposesisrecommended.

ceduresforobtainingrepresentativebasemetalsamples,for

removingthespecimensfromthesamples,andthenumberof

ure

specimensshallbeatthediscretionoftheproducer.

34.1Useasufficientquantityofthenitricacidtestsolution

32.3Whenspecimensarecutbyshearing,theshearededges

tocover

2

thespecimensandtoprovideavolumeofatleast20

shallberefinishedbymachiningorgrindingpriortotesting.

mL/cm(125mL/in.

2

)ly,a

volumeofabout600mLisused.

ationofTestSpecimens

34.2Useaseparatecontainerforeachtestspecimen.

33.1Heattreatextra-lowcarbonandstabilizedgradesat

34.2.1Asmanyasthreespecimensmaybetestedinthe

650to675°C(1200to1250°F),whichistherangeof

samecontainerprovidedthattheyallareofthesamegradeand

maximumcarbideprecipitation,gthof

allshowsatisfactoryresistancetocorrosion.

timeofheating,andthemethodofsubsequentcoolingusedfor

34.2.2Ifmorethanoneofthespecimenstestedinthesame

thissensitizingtreatmenttogetherwiththecorresponding

containerfailtopassthetest,retestallthespecimensin

maximumpermissiblecorrosionrateshallbeasagreedbe-

separatecontainers.

tweenthematerialproducerandpurchaser.

N

OTE

14—Excessivecorrosionofonespecimenmayresultinacceler-

N

ivecorrosion

OTE

11—Themostcommonlyusedsensitizingtreatmentis1hat

675°C(1250°F).

mayoftenbedetectedbychangesinthecolorofthetestsolution,andit

N

maybeappropriatetoprovideseparatecontainersforsuchspecimens

OTE

12—Thesizeandshapeofthespecimenmustbeconsideredwith

respecttoavailablefacilitiesforaccurateweighingandthevolumeoftest

dshouldbemade

ly,themaximumconvenientweightofa

showingwhichspecimensweretestedtogether.

aseofbar,wire,andtubularproducts,the

34.3Afterthespecimenshavebeenplacedintheacidinthe

proportionofthetotalarearepresentedbytheexposedcrosssectionmay

container,passcoolingwaterthroughthecondenser,bringthe

infl-sectionalareasintheseproductsmaybe

portionofendgraininthe

acidtoaboilonthehotplate,andkeepboilingthroughoutthe

specimenshouldthereforebekeptlowunlesssuchsurfaceisactuallyto

testperiod(Note15).Aftereachtestperiod,rinsethespeci-

lattercase,the

menswithwaterandtreatbyscrubbingwithrubberoranylon

proportionofendgraininthespecimenshouldbekepthigh.

brushunderrunningwatertoremoveanyadheringcorrosion

33.2Wherefeasiblefortheproductform,grindallthe

products,maybefacilitated,

specimensurfacesusingCAMI/ANSI120[FEPA/ISOP120]

ifdesired,bydippingthespecimensinacetoneaftertheyare

paper-backed,wetordry,closedcoatedabrasivepaper,with

scrubbed.

sivepaperisuseddry,polishslowly

34.4(Warning—Ithasbeenreportedthatviolentboiling

seabrasiveswithgrindingaids;

portanttoensurethat

somegrindingaidscontainfluoridesthatcanaffectthe

theconcentrationofaciddoesnotincreaseandthatanadequate

measuredcorrosionrate.

numberofboilingchips(whichareresistanttoattackbythe

33.3Removealltracesofoxidescaleandheattintformed

testsolution)arepresent.)

lethatcannotberemovedby

N

OTE

15—Takecaretopreventcontaminationofthetestingsolution,

grinding(forexample,instampednumbers)mayberemoved

especiallybyfluorides,encehas

byusingoneofthepicklingsolutionsdescribedinPractice

shownthatthepresenceofevensmallamountsofhydrofluoricacidwill

A380/A380M,TableA1.1.

tpermissible,for

example,toconductnitric-hydrofluoricacidtestsinthesamehoodwith

33.4Measurethespecimen,includingtheinnersurfacesof

nitricacidtests.

anyholestothenearest0.05mm(0.001in.),andcalculatethe

34.5Thestandardtestconsistsoffiveboilingperiodsof

totalexposedareaincm

2

.

48heachwithafreshtestsolutionbeingusedineachperiod.

33.5Degreasethespecimenusingsuitablenonchlorinated

34.5.1Acombinationofone48-hperiodandtwo96-h

agents,suchassoapandlukewarmwater,oracetone(Note13).

periods(notnecessarilyinthatorder)insteadoffive48-htest

Drythespecimensandweigheachonetothenearest0.001g.

periodsmaybeusedifsoagreedbythepurchaser.

Storethespecimensinadesiccatoruntilthetestistobe

performed.

ationandReport

N

35.1Calculation—Theeffectoftheacidonthematerial

OTE

13—Thecleaningtreatmentdescribedmaybesupplementedby

immersingthespecimeninnitricacid(forexample,20weight%at49to

shallbemeasuredbydeterminingthelossofweightofthe

60°C(120to140°F))for20min,followedbyrinsing,drying,and

specimenaftereachtestperiodandforthetotalofthetest

aseofsmall-diametertubularspecimenswhichcannot

q1,calculatethecorrosionrateforeach

beconvenientlyresurfacedontheinside,itisdesirabletoincludeinthe

specimenforeachtestperiod,andforthetotalofthetest

preparationanimmersioninboilingnitricacid(65%)for2to4husing

poseofthesetreatments

periods.

istoremoveanysurfacecontaminationthatmaynotbeaccomplishedby

35.2Report—Reportthecalculatedcorrosionratesforthe

theregularcleaningmethodandwhichmayincreasetheapparentweight

individualperiodsinchronologicalorder,aswellasthe

10

-

-

-

`

,

,

`

,

`

,

,

`

,

,

`

-

`

-

`

`

`

,

,

`

,

`

`

`

,

,

,

,

,

,

`

,

,

`

,

`

`

,

`

`

,

`

,

`

-

-

A262−15

averageforthefiodifiedtestperiods

(

34.5.1)areused,thenidentifyeachresultastothesequence

andlengthofthetestperiod.

ionandBias

36.1Precision—TheprecisionofPracticeCisbeingdeter-

mined.

36.2Bias—Thispracticehasnobiasbecausetheresistance

tointergranularcorrosionisdefinedonlyintermsofthis

practice.

PRACTICEE—COPPER-COPPERSULFATE–16%

SULFURICACIDTESTFORDETECTING

SUSCEPTIBILITYTOINTERGRANULAR

ATTACKINAUSTENITICSTAINLESSSTEELS(

4,5)

37.1Thispracticedescribestheprocedurebywhichthe

copper–coppersulfate–16%sulfuricacidtestisconductedto

determinethesusceptibilityofausteniticstainlesssteelsto

senceorabsenceofintergranular

corrosioninthistestisnotnecessarilyameasureofthe

t

doesnotprovideabasisforpredictingresistancetootherforms

ofcorrosion,suchasgeneralcorrosion,pitting,orstress-

corrosioncracking.

creeningTest

38.1Beforetestinginthecopper–coppersulfate–16%sul-

furicacidtest,specimensofcertaingradesofstainlesssteel

(see

Table4)maybegivenarapidscreeningtestinaccordance

withtheproceduresgiveninPracticeA(Sections4through

13).Preparation,etching,andtheclassificationofetchstruc-

ofetch-structureevalua-

tionsinconnectionwiththecopper–coppersulfate–16%

sulfuricacidtestisspecifiedinTable4.

38.1.1Corrosiontestspecimenshavingacceptableetch

structuresintheOxalicAcidEtchTestwillbeessentiallyfree

ofintergranularattackinthecopper–coppersulfate–16%

ecimensareacceptablewithout

TABLE4UseofEtchStructureClassificationsfromtheOxalic

AcidEtchTestwiththeCopper–CopperSulfate–16%Sulfuric

AcidTest

Grade

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

A

testinginthecopper–coppersulfate–16%

specimenshavingsuspectetchstructuresmustbetestedinthe

copper–coppersulfate–16%sulfuricacidtest.

38.1.2Heattreatthematerialwhenrequiredbyandin

accordancewith

43.3.1priortoperformingtheetchtest.

yofPractice

39.1Asuitablesampleofanausteniticstainlesssteel,

embeddedincoppershotorgrindings,isexposedtoboiling

acidifixposureinthe

boilingsolution,ranularcrackingor

crazingisevidenceofsusceptibility.

39.2AlternativeTestingProcedures:

39.2.1Unlessprohibitedbythepurchaserinthepurchase

order,thesupplierispermittedtomeettherequirementsof

PracticeEbyperformingatestinaccordancewithISO

3651–2,MethodA,providedthatthetestingperiodshallbea

ensitizationtreatmentisrequired,

sensitizationheattreatmentT1[700°C610°C

(1292°F618°F),30min,waterquench]shallbeusedunless

thesupplierandpurchasershallagreeuponpreparationof

weldedtestpiecestobetestedintheas-weldedcondition.

39.2.2Whenthisalternativetestprocedureisused,itshall

benotedonthetestreport.

tus

40.1ThebasicapparatusisdescribedinSection

18.

40.2SpecimenSupports—Anopenglasscradlecapableof

supportingthespecimensandcoppershotorgrindingsinthe

flaskisrecommended.

N

OTE

16—Itmaybenecessarytoembedlargespecimens,suchasfrom

heavybarstock,incoppershotonthebottomofthetestflr

cradlemayalsobeused.

40.3HeatSource—Anygasorelectricallyheatedhotplate

maybeutilizedforheatingthetestsolutionandkeepingit

boilingthroughoutthetestperiod.

fiedCopperSulfateTestSolution

41.1Dissolve100gofreagentgradecoppersulfate

(CuSO

4

·5H

2

O)in700mLofdistilledwater,add100mLof

sulfuricacid(H

2

SO

4

,cp,spgr1.84),anddiluteto1000mL

withdistilledwater.

N

OTE

17—Thesolutionwillcontainapproximately6weight%of

anhydrousCuSO

4

and16weight%ofH

2

SO

4

.

AcceptableEtch

Structures

Step,

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,

end

end

end

end

end

end

end

end

end

end

end

end

end

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

I

I

I

I

I

I

I

I

I

I

I

I

I

and

and

and

and

and

and

and

and

and

and

and

and

and

II

II

II

II

II

II

II

II

II

II

II

II

II

SuspectEtch

Structures

A

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

201

202

301

304

304L

304H

316

316L

316H

317

317L

321

347

Addition

42.1Electrolyticgradecoppershotorgrindingsmaybe

preferredforitseaseofhandlingbeforeandafter

thetest.

42.2Asufficientquantityofcoppershotorgrindingsisto

beusedtocoverallsurfacesofthespecimenwhetheritisina

ventedglasscradleorembeddedinalayerofcoppershoton

thebottomofthetestflask.

42.3Theamountofcopperused,assuminganexcessof

metalliccopperispresent,ectivegalvanic

couplingbetweencopperandthetestspecimenmayhave

importance(

6).

11

Specimenshavingthesestructuresmustbetestedinthecopper–copper

sulfate–16%sulfuricacidtest.

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

A262−15

42.4Thecoppershotorgrindingsmaybereusediftheyare

1hat675°ouldbetakentoavoidcarburizingor

cleanedinwarmtapwateraftereachtest.

ttreatingisbestcarriedoutin

enPreparation

airorneutralsalt.

43.1Thesizeofthesamplesubmittedfortestandthearea

N

OTE

18—Thesensitizingtreatment675°Cisperformedtocheckthe

effectivenessofstabilizedand0.03%maximumcarbonmaterialsin

fromwhichitistobetaken(endormiddleofcoil,midway

resistingcarbideprecipitation,hence,intergranularattack.

surfaceandcenter,andsoforth)isgenerallyspecifiedinthe

ting

nditions

apparatusdictatesthefinalsizeandshapeofthetestspecimen.

44.1Thevolumeofacidifiedcoppersulfatetestsolution

Thespecimenconfigurationshouldpermiteasyentranceand

usedshouldbesufficienttocompletelyimmersethespecimens

removalthroughtheneckofthetestcontainer.

andprovideaminimumof8mL/cm

2

(50mL/in.

2

)ofspecimen

43.1.1

Table5maybeusedasaguidetodetermine

surfacearea.

ayberestrictionsplacedon

44.1.1Asmanyasthreespecimenscanbetestedinthesame

specimensizebythetestingapparatus.

ealtohaveallthespecimensinoneflasktobe

43.1.2Specimensobtainedbyshearingshouldhavethe

ofthesamegrade,

solutionvolume-to-samplearearatioistobemaintained.

shouldbetakenwhengrindingtoavoidoverheatingor

44.1.2Thetestspecimen(s)shouldbeimmersedinambient

“burning.”A“squared”edgeisdesirable.

testsolution,whichisthenbroughttoaboilandmaintained

43.2Anyscaleonthespecimensshouldberemovedme-

imingthetestperiod

chanicallyunlessaparticularsurfacefinishistobeevaluated.

whenthesolutionreachestheboilingpoint.

Chemicalremovalofscaleispermissiblewhenthisisthecase.

N

OTE

19—Measuresshouldbetakentominimizebumpingofthe

Mechanicalremovalofscaleshouldbeaccomplishedwith

120-gritiron-freealuminumoxideabrasive.

amountofcoppershot(eighttotenpieces)onthebottomoftheflaskwill

43.2.1Eachspecimenshouldbedegreasedusingacleaning

convenientlyservethispurpose.

solventsuchasacetone,alcohol,ether,oravapordegreaser

44.1.3Thetimeofthetestshallbeaminimumof15h,

priortobeingtested.

unlessalongertimeisagreeduponbetweenthepurchaserand

43.3Allausteniticmaterialinthe“as-received”(mill-

15h,thetesttimeshallbespecifiedonthe

annealed)conditionshouldbecapableofmeetingthistest.

estsolutionwouldnotbeneededifthetest

43.3.1Specimensofextra-low-carbonandstabilizedgrades

weretorun48oreven72h.(Ifanyadherentcopperremains

aretestedaftersensitizingheattreatmentsat650to675°C

onthespecimen,itmayberemovedbyabriefimmersionin

(1200to1250°F),whichistherangeofmaximumcarbide

concentratednitricacidatroomtemperature.)

tcommonlyusedsensitizingtreatmentis

N

OTE

20—Resultsintheliteratureindicatethatthistestismore

sensitiveifitisrunforlongertimes(3,7).

TABLE5SizesofTestSpecimens

st

TypeofMaterialSizeofTestSpecimen

45.1Thetestspecimenshallbebentthrough180°andover

Wroughtwireorrod:

adiameterequaltothethicknessofthespecimenbeingbent

Upto6mm(¼in.)indiameter,inclFulldiameterby75mm(3in.)(min)

long

(seeFig.10).Innocaseshallthespecimenbebentovera

Over6mm(¼in.)indiameterCylindricalsegment6mm(¼in.)thick

by25mm(1in.)(max)wideby75

to125mm(3to5in.)long

A

Wroughtsheet,strip,plates,orflat

rolledproducts:

Upto5mm(

3

⁄

16

in.)thick,inclFullthicknessby9to25mm("to

1in.)wideby75mm(3in.)(min)

long

Over5mm(

3

⁄

16

in.)thick5to13mm(

3

⁄

16

to½in.)thickby

9to25mm("to1in.)wideby

75mm(3in.)(min)long

B

Tubing:

Upto38mm(1½in.)indiameter,inclFullring,25mm(1in.)wide

C

Over38mm(1½in.)indiameterAcircumferentialsegment75mm

(3in.)(min)longcutfroma25mm

(1-in.)widering

D

A

Whenbendingsuchspecimens,thecurvedsurfaceshallbeontheoutsideofthe

bend.

B

Onesurfaceshallbeanoriginalsurfaceofthematerialundertestanditshallbe

-rolledstriporsheetsmaybetestedinthe

thicknesssupplied.

C

Ringsectionsarenotflattenedorsubjectedtoanymechanicalworkbeforethey

aresubjectedtothetestsolution.

D

Specimensfromweldedtubesover38mm(1½in.)indiametershallbetaken

withtheweldontheaxisofthebend.

FIG.10ABentCopper–CopperSulfate–SulfuricAcid

TestSpecimen

12

-

-

-

`

,

,

`

,

`

,

,

`

,

,

`

-

`

-

`

`

`

,

,

`

,

`

`

`

,

,

,

,

,

,

`

,

,

`

,

`

`

,

`

`

,

`

,

`

-

-

A262−15

smallerradiusorthroughagreateranglethanthatspecifiedin

theproductspecifisofmaterialhavinglow

ductility,suchasseverelycoldworkedmaterial,a180°bend

hallinformthoseconductingthe

PracticeEtestwhenthematerialisinthelowductilityhighly

stressedcondition,suchashighlycoldworkedmaterial.

Determinethemaximumangleofbendwithoutcausingcracks

insuchmaterialbybendinganuntestedspecimenofthesame

confixposureto

theacidifiedcopper–coppersulfatesulfuricacidtestsolution,

themaximumangleofbendwithoutcausingcracksasdeter-

minedfromuntestedlowductilityspecimensshallbeutilized

inevaluationofthespecimensexposedtotheacidified

copper–leof

bendutilizedinevaluatingtestedspecimensshallbereported.

45.1.1Duplicatespecimensshallbeobtainedfromsheet

materialsothatbothsidesoftherolledsamplesmaybebent.

Thiswillassuredetectionofintergranularattackresultingfrom

carburizationofonesurfaceofsheetmaterialduringthefinal

stagesofrolling.

N

OTE

21—Identifytheduplicatespecimeninsuchamannerasto

ensurebothsurfacesofthesheetmaterialbeingtestedaresubjectedtothe

tensionsideofthebends.

45.1.2Samplesmachinedfromroundsectionsorcastma-

terialshallhavethecurvedororiginalsurfaceontheoutsideof

thebend.

45.1.3Thespecimensaregenerallybentbyholdinginavise

nerallycompleted

pecimens

mayrequirebendinginafir

hydraulicpressmayalsobeusedforbendingthespecimens.

45.1.4Tubularproductsshouldbeflattenedinaccordance

withtheflatteningtest,prescribedinTestMethodsand

Definitions

A370.

45.1.5Whenagreeduponbetweenthepurchaserandthe

producer,thefollowingshallapplytoausteniticstainlesssteel

plates4.76mm(0.1875in.)andthicker:

45.1.5.1Samplesshallbepreparedaccordingto

Table5.

45.1.5.2Theradiusofbendshallbetwotimesthesample

thickness,andthebendaxisshallbeperpendiculartothe

directionofrolling.

45.1.5.3Weldsonmaterial4.76mm(0.1875in.)andthicker

shallhavetheabovebendradius,andtheweld-basemetal

interfaceshallbelocatedapproximatelyinthecenterlineofthe

bend.

45.1.5.4Face,root,orsidebendtestsmaybeperformed,

andthetypeofbendtestshallbeagreeduponbetweenthe

dradiusshallnotbeless

thanthatrequiredformechanicaltestingintheappropriate

materialspecification(forbasemetal)orinASMECode

SectionIX(forwelds).

tion

46.1Thebentspecimenshallbeexaminedunderlow(5to

20×)magnification(see

Fig.11).Theappearanceoffissuresor

FIG.11PassingTestSpecimen—ViewoftheBentArea(20×MagnificationBeforeReproduction)

13

A262−15

cracksindicatesthepresenceofintergranularattack(seeFig.

12

).

46.1.1Whenanevaluationisquestionable(seeFig.13),the

presenceorabsenceofintergranularattackshallbedetermined

bythemetallographicexaminationoftheouterradiusofa

longitudinalsectionofthebendspecimenatamagnificationof

100to250×.

46.1.2Crackingthatoriginatesattheedgeofthespecimen

earanceofdeformationlines,

wrinkles,or“orangepeel”onthesurface,withoutaccompa-

nyingcracksorfissures,shallbedisregardedalso.

46.1.3Crackssuspectedasarisingthroughpoorductility

shallbeinvestigatedbybendingasimilarspecimenthatwas

lcomparison

betweenthesespecimensshouldassistininterpretation.

PRACTICEF—COPPER-COPPERSULFATE–50%

SULFURICACIDTESTFORDETERMINING

SUSCEPTIBILITYTOINTERGRANULARATTACK

INAUSTENITICSTAINLESSSTEELS

47.1Thispracticedescribestheprocedureforconducting

theboilingcopper–coppersulfate–50%sulfuricacidtest,

whichmeasuresthesusceptibilityofstainlesssteelstointer-

granularattack.

47.2Thepresenceorabsenceofintergranularattackinthis

testisnotnecessarilyameasureoftheperformanceofthe

tdoesnot

provideabasisforpredictingresistancetoformsofcorrosion

otherthanintergranular,suchasgeneralcorrosion,pitting,or

stress-corrosioncracking.

yofTestMethodF,theCopper–Copper

Sulfate–50%SulfuricAcidTest

48.1Aspecimenrepresentativeofthematerialtobeevalu-

atedisimmersedinaboilingsolutionofcoppersulfateand

sulfuricacidforaspecifiofcopperisalso

immersedinthesolutiontomaintainaconstantcorrosion

ultingmasslossisconvertedtoacorrosion

rate,whichiscomparedtoaspecifiedmaximumvalueto

determinewhetherthematerialhastheresistancetoattack

expectedofthegradeofmaterialbeingtested.

ficanceandUse

49.1Thecopper–coppersulfate–sulfuricacidtestdetects

susceptibilitytointergranularattackassociatedprimarilywith

chromiumcarbideprecipitateinunstabilizedcastaustenitic

stainlesssteelsandincertainwroughtgrades.

49.2Thecopper–coppersulfate–sulfuricacidtestdoesnot

detectsusceptibilitytointergranularattackassociatedprimarily

withsigmaphase.

49.3Thecorrosionpotentialofthecopper–coppersulfate-

–sulfuricacidtesthasbeenreportedas0.1Vascomparedwith

0.6VforPracticeB,0.75to1.0VforPracticeC,and0.1Vfor

PracticeE.(

3)

N

OTE

22—Highercorrosionpotentialindicatesmoreseverelyoxidizing

conditions.

creeningTest

50.1Beforetestinginthecopper–coppersulfate–50%sul-

furicacidtest,specimensofcertaingradesofstainlesssteels

(seeTable6)maybegivenarapidscreeningtestinaccordance

withproceduresgiveninPracticeA,OxalicAcidEtchTestfor

FIG.12FailingTestSpecimen(Notethemanyintergranularfieaat20×MagnificationBeforeReproduction.)

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

14

A262−15

FIG.13NotetheTracesofIntergranularFissuresand“Orange-Peel”eaat20×Magnification

BeforeReproduction.)

TABLE6UseofEtchStructureClassificationsfromtheOxalic

AcidEtchTestWiththeCopper–CopperSulfate–50%Sulfuric

AcidTest

A

Grade

CF-3M

CF-8M

A

tus

51.1ThebasicapparatusisdescribedinSection

18.

51.1.1Substitutionsforthiscondenserorflaskarenot

fically,thecold-fingertypeofcondenserwith

standardErlenmeyerflionrates

obtainedusingthecold-fingertypeofcondenserarelowerthan

thoseobtainedusingtheAllihntypeofcondenserwhetherdue

tolossofvaporortohigheroxygencontentinthesolutionor

both.

tsandMaterials

52.1CupricSulfatePentahydrate(CuSO

4

·5H

2

O);about

64%(CuSO

4

)bymass.

52.1.1Cupricsulfateisaspecificadditivethatestablishes

tutionsarenot

permitted.

52.2SulfuricAcid(H

2

SO

4

),95.0to98.0%bymass.

52.3Apieceofcoppermetalabout3by20by40mm(

1

⁄

8

by

3

⁄

4

by1

1

⁄

2

in.)withabright,cleanfivalentarea

ofcoppershotorchipsmaybeused.

52.3.1Wash,degrease,anddrythecopperbeforeuse.

N

OTE

23—Arinsein5%H

2

SO

4

willcleancorrosionproductsfromthe

copper.

AcceptableEtchStructures

Step,dual,isolatedferrite

Step,dual,isolatedferrite

SuspectEtchStructures

B

Ditch,interdendriticditches

Ditch,interdendriticditches

GradesnotlistedinthistableeitherhavenotbeenevaluatedforuseofPractice

AwithPracticeForhavebeenfoundtogiveacceptableresultsintheetchtest

attercasePracticeAwould

passmaterialthatshouldhavebeensubjectedtothecopper–coppersulfate-

sulfuricacidtest.

B

Specimenshavingthesestructuresshallbetestedinthecopper–copper

sulfate-sulfuricacidtest

ClassificationofEtchStructuresofAusteniticStainlessSteels.

Preparation,etching,andtheclassificationofetchstructures

ofetchstructureevaluationsin

connectionwiththecopper–coppersulfate–50%sulfuricacid

testisspecifiedinTable6.

50.2Heattreatthematerialinaccordancewith55.1priorto

performingtheetchtest.

50.3Ignore“process-affected”areas(see54.1.1);applica-

tionoftheetchtesttotheseareasiscurrentlyoutsidethescope

ofPracticeF.

50.4Corrosiontestspecimenshavingacceptableetchstruc-

turesintheOxalicAcidEtchTestwillbeessentiallyfreeof

intergranularattackinthecopper–coppersulfate–50%sulfuric

ecimensareacceptablewithouttestinginthe

copper–coppersulfate–50%cimens

havingsuspectetchstructuresshallbetestedinthecopper-

–coppersulfate–50%sulfuricacidtest.

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

–CopperSulfate–50%SulfuricAcidTest

Solution

53.1Prepare600mLoftestsolutionasfollows:

53.1.1(Warning—Protecttheeyesandfacebyfaceshield

flaskunderhood.)

15

A262−15

53.1.2First,measure400.0mLofTypeIVreagentwater

andpourintotheErlenmeyerflask.

53.1.3Thenmeasure236.0mLofreagentgradesulfuric

acidslowlytothewaterintheErlenmeyerflask

toavoidboilingbytheheatevolved.(Note7.)

53.1.4Weigh72gofreagentgradecoppersulfate(CuSO

4

·5

H

2

O)andaddtothesulfuricacidsolution.

53.1.5Placethecopperpieceintooneglasscradleandput

itintotheflask.

53.1.6Dropboilingchipsintotheflask.

53.1.7Lubricatetheground-glassjointwithsiliconegrease.

53.1.8Covertheflaskwiththecondenserandcirculate

coolingwater.

53.1.9Heatthesolutionslowlyuntilallofthecoppersulfate

isdissolved.

53.1.10(Warning—Ithasbeenreportedthatviolentboiling

portanttoensurethat

theconcentrationofaciddoesnotincreaseandthatanadequate

numberofboilingchips(whichareresistanttoattackbythe

testsolution)arepresent.)

ng

54.1Obtainandprepareonlybasemetalsamples.

54.1.1Therearetwoclassesofspecimenstobeconsidered:

basemetal,s-affectedmetal

containsanyconditionthataffectsthecorrosionpropertiesof

thematerialinanon-uniformway,suchas(butnotlimitedto)

welds;carburized,nitrided,oroxidizedsurfaces;mechanical

deformation;talhasnone

oftheseconditions.

54.1.2ThePracticeFtestinvolvesimmersingtheentire

specimenandaveragingthemasslossovertheentiresurfaceof

g,carburization,mechanicaldeformation,

andthelike,affectonlypartofaspecimen.

54.1.3Themasslossratefromprocess-affectedmetalis

expectedtodifferfromthatfrombasemetal;thepresenceof

process-affectedmetalinaspecimenwillaffectthecalculated

testresultinanunpredictableway.

54.1.4Ifthepresenceoftheseorotherlocalizedconditions

isaconcerntothepurchaser,thenteststhatdonotaveragethe

masslossoverthetotalspecimensurfacearea,suchasPractice

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

Sulfate–16%SulfuricAcidTestforDetectingSusceptibilityto

IntergranularAttackinAusteniticStainlessSteels,shouldbe

softhetestandacceptancecriteriashallbe

asagreedbythepurchaserandproducer.

54.2Unlessotherwisespecifiedbythepurchaser,thepro-

ceduresforobtainingrepresentativebasemetalsamples,for

removingthespecimensfromthesamples,andthenumberof

specimensshallbeatthediscretionoftheproducer.

ationofTestSpecimens

55.1Heattreatextra-lowcarbonandstabilizedgradesat

650to675°C(1200to1250°F),whichistherangeof

maximumcarbideprecipitation,gthof

timeofheating,andthemethodofsubsequentcoolingusedfor

thissensitizingtreatmenttogetherwiththecorresponding

16

maximumpermissiblecorrosionrateshallbeasagreedbe-

tweenthematerialproducerandpurchaser.

N

OTE

24—Themostcommonlyusedsensitizingtreatmentis1hat

675°C(1250°F).

55.2Preparethespecimens,eachhavingatotalsurfacearea

of5to20cm

2

.

55.3Wherefeasiblefortheproductform,grindallthe

specimensurfacesusingCAMI/ANSI120[FEPA/ISOP120]

paper-backed,wetordry,closedcoatedabrasivepaper,with

sivepaperisuseddry,polishslowly

seabrasiveswithgrindingaids;

somegrindingaidscontainfluoridesthatcanaffectthe

measuredcorrosionrate.

55.4Removealltracesofoxidescaleandheattintformed

lethatcannotberemovedby

grinding(forexample,instampednumbers)mayberemoved

byusingoneofthepicklingsolutionsdescribedinPractice

A380/A380M,TableA1.1.(Residualoxidescalecausesgal-

vanicactionandconsequentactivationinthetestsolution.)

55.5Measurethespecimens,includingtheinnersurfacesof

anyholes,tothenearest0.05mm(0.001in.)andcalculatethe

totalexposedarea.

55.6Degreasethespecimensusingsuitablenonchlorinated

agents,suchassoapandlukewarmwater,

he

specimensinadesiccatoruntilthetestistobeperformed.

ure

56.1Ifthetestsolutionisnotalreadyboiling,bringitto

boiling.

56.1.1Keeptheflaskcoveredwiththecondenser(with

coolingwaterflowing)exceptwheninsertingorremoving

specimens.(See

Note7.)

56.2Turnofftheheatsourceandallowtheboilingto

subside.

56.3Placethespecimeninasecondglasscradle.

56.4Uncovertheflask.

56.5Insertthespecimens.

56.6Replacethecondenserimmediately,restorecooling

waterflow,andturnontheheatsource.

56.7Marktheliquidlevelontheflasktoprovideacheckon

vaporloss,

thereisanappreciablechangeinthelevel,repeatthetestwith

freshsolutionandaregroundspecimen.

56.8Continueimmersionofthespecimenfor120h,then

removethespecimen,rinseinwaterandacetone,

anyadherentcopperremainsonthespecimen,itmaybe

removedbyabriefimmersioninconcentratednitricacidat

roomtemperature.

56.9Weighthespecimenandsubtracttheweightfromthe

originalweight.

A262−15

56.10Intermediateweighingsareusuallynotnecessary;the

r,ifpreliminary

resultsaredesired,thespecimencanberemovedatanytime

forweighing.

56.11Changestothesolutionduringthe120-htestperiod

arenotnecessary.

ationandReport

57.1Theeffectoftheacidsolutiononthematerialis

measuredbydeterminingthelossofweightofthespecimen.

Thecorrosionrateshouldbereportedasmillimetresof

penetrationpermonth(

Note9)calculatedusingEq1.

ds

59.1austeniticstainlesssteel;coppersulfate;corrosion

testing;etchstructures;ferricsulfate;intergranularcorrosion;

nitricacid;oxalicacid

ionandBias

58.1Precision—TheprecisionofPracticeFisbeingdeter-

mined.

58.2Bias—Thispracticehasnobiasbecausetheresistance

tointergranularcorrosionisdefinedonlyintermsofthis

practice.

APPENDIX

NonmandatoryInformation

ATIONOFTHESETESTMETHODS

X1.1General

X1.1.1Thesetestmethodsdetectoneormoreofthree

typesofsusceptibilitytointergranularattack:chromium

carbide,sigmaphase,iceoftestmethod

isaffectedbytheintendedservice,thetypeortypesofattack

expectedfromthatservice,andthegradeofmaterialtobe

evaluated.

X1.1.2Thesepracticesdescribetheproceduresbywhich

thetestsareconductedtodeterminethesusceptibilityof

sence

orabsenceofintergranularcorrosioninthesetestsisnot

necessarilyameasureoftheperformanceofthematerialin

tsdonotprovideabasisfor

predictingresistancetootherformsofcorrosion,suchas

generalcorrosion,pitting,orstress-corrosioncracking.

X1.1.3Susceptibilitytointergranularattackassociatedwith

theprecipitationofchromiumcarbidesisreadilydetectedinall

fivetests.

X1.1.4Sigmaphasemaybepresentinwroughtchromium-

nickel-molybdenumsteels,intitanium-orcolumbium-

stabilizedalloys,andincastmolybdenum-bearingstainless

gmaphasemayormaynotbevisibleinthe

microstructuredependingontheetchingtechniqueandmag-

nifiofthetestmethodscandetectsigma

phase;seethediscussionsbelow.

X1.1.5Inmostcaseseitherthe15-hcopper–coppersul-

fate–16%sulfuricacidtestorthe120-hferricsulfate-sulfuric

acidtest,combinedwiththeOxalicAcidEtchTest,will

stainlessgradeslistedinthisappendixmaybeevaluatedin

thesecombinationsofscreeningandcorrosiontests,except

thosespecimensofmolybdenum-bearinggrades(forexample

316,316L,317,and317L),whichrepresentsteelintendedfor

useinnitricacidenvironments.

X1.1.6The240-hnitricacidtestshouldbeappliedto

stabilizedandmolybdenum-bearinggradesintendedforser-

viceinnitricacidandtoallstainlesssteelgradesthatmightbe

subjecttoendgraincorrosioninnitricacidservice.

X1.1.7Extensivetestresultsonvarioustypesofstainless

steelsevaluatedbythesepracticeshavebeenpublishedin(

8).

17

A262−15

PRACTICEA—OXALICACIDETCHTEST

X1.2TheOxalicAcidEtchTestisusedforacceptanceof

ybeusedin

connectionwithotherevaluationteststoprovidearapid

methodforidentifyingthosespecimensthatarecertaintobe

freeofsusceptibilitytorapidintergranularattackintheseother

tests.

X1.2.1Theetchtestissuitableforuseonlywhenitislisted

intheapplicabletableunderthespecifiedhotacidtest.

X1.2.2Gradesnotlistedintheapplicabletableeitherhave

notbeenevaluatedforuseofPracticeAwiththathotacidtest,

orhavebeenfoundtogiveacceptableresultsintheetchtest

lattercasetheetchtestwouldpassmaterialthatshouldhave

beenrejected.

X1.2.3Whenlisted,theetchtestcanreducethetime

requiredtodeterminewhetherthematerialrepresentedbythe

specimenwillhavealowcorrosionrateinthathotacidtest.

However,whentheetchtestshowsasuspectstructure,the

specifiedhotacidmustbeperformedtoavoidrejectinggood

material.

PRACTICEB—FERRICSULFATE-SULFURICACIDTEST

X1.3PracticeB—Ferricsulfate-sulfuricacidtestisa120-h

testinboilingsolution.

X1.3.1Theferricsulfate-sulfuricacidtestmaybeusedto

mayalsobeusedtochecktheeffectivenessofstabilizing

columbiumortitaniumadditionsandofreductionsincarbon

contentinpreventingsusceptibilitytorapidintergranular

eappliedtowroughtproducts(includingtubes),

castings,andweldmetal.

X1.3.2Theferricsulfate-sulfuricacidtestdetectssuscepti-

bilitytointergranularattackassociatedprimarilywithchro-

miumcarbideprecipitateintheunstabilizedausteniticstainless

steels304,304L,316,316L,317,317L,CF-3,CF-8,CF3M,

CF8M,CG3M,andCG8M;tointergranularattackassociated

withsigmaphasein321,347,CF-3M,CF-8M,CG3M,and

revealssusceptibilityassociatedwithasigma-

likephaseconstituentinstabilizedstainlesssteels321and347,

andincastchromium-nickel-molybdenumstainlesssteels

CF-3M,CF-8M,CG-3M,andCG-8M.

X1.3.3Theferricsulfate-sulfuricacidtestdoesnotdetect

susceptibilitytointergranularattackassociatedprimarilywith

sigmaphaseinwroughtchromium-nickel-molybdenumstain-

lesssteels(316,316L,317,317L),whichisknowntoleadto

doesnotdetectsusceptibilitytoendgrainattack,whichisalso

foundincertainnitricacidenvironments.

N

OTE

X1.1—Todetectsusceptibilitytointergranularattackassociated

withsigmaphaseinausteniticstainlesssteelscontainingmolybdenum,the

nitricacidtest,PracticeC,shouldbeused.

X1.3.4TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestingintheferricsulfate-

sulfuricacidtest;notlistedinTable1

eitherhavenotbeenevaluatedforuseofPracticeAwiththe

ferricsulfate-sulfuricacidtestorhavebeenfoundtogive

acceptableresultsintheetchtestwhilegivingunacceptable

resultsintheferricsulfate–sulfuricacidtest,thuspassing

materialthatshouldberejected.

PRACTICEC—NITRICACIDTEST

X1.4PracticeC—Nitrictestisa240-htestinboiling

solution.

X1.4.1Theboilingnitricacidtestmaybeusedtoevaluate

theheattreatmentaccorded“as-received”so

sometimesusedtochecktheeffectivenessofstabilizing

elementsandofreductionsincarboncontentinpreventing

acticemay

beappliedtowroughtproducts(includingtubes),castings,and

weldmetalofthevariousgradesofstainlesssteel

X1.4.2Intergranularattackinnitricacidisassociatedwith

oneormoreofthefollowing:intergranularprecipitationof

chromiumcarbides,sigmaortransitionphasesin

molybdenum-bearinggrades,andsigmaphaseconstituentsin

lingnitricacidtestshouldnotbeused

18

forextra-low-carbonmolybdenum-bearinggradesunlessthe

materialtestedistobeusedinnitricacidservice.

X1.4.3ThePracticeCtestdetectssusceptibilitytorapid

intergranularattackassociatedwithchromiumcarbideprecipi-

termaybe

formedinmolybdenum-bearingandinstabilizedgradesof

austeniticstainlesssteelsandmayormaynotbevisibleinthe

stalsorevealssusceptibilitytoendgrain

attackinallgradesofstainlesssteels.

X1.4.4Thenitricacidtestdetectssusceptibilitytointer-

granularattackassociatedprimarilywithchromiumcarbide

precipitatein304,304L,316,316L,317,317L,321,347,

CF-3,CF-8,CF-3M,andCF-8M;tointergranularattack

associatedwithsigmaphasein316,316L,317,317L,321,

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

A262−15

347,CF-3M,andCF-8M;andtoend-grainattackin304,304L,

316,316L,317,317L,321,ricacidtestmay

bealsoappliedto309,310,348,410,430,446,andCN-7M.

Thosegradesinwhichsigmaphasemayformmustbetestedin

nitricacidtestwhendestinedforserviceinnitricacid.

X1.4.5TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestinginthenitricacidtest;see

notlistedinTable2eitherhavenotbeen

evaluatedforuseofPracticeAwiththenitricacidtestorhave

beenfoundtogiveacceptableresultsintheetchtestwhile

givingunacceptableresultsinthenitricacidtest,thuspassing

fically,grades316,316L,

317,317L,347,and321cannotbescreenedbecausethese

steelsmaycontainsigmaphasenotvisibleintheetchstructure.

Thismaycauserapidintergranularattackinthenitricacidtest.

PRACTICEE—COPPER–COPPERSULFATE–16%SULFURICACIDTEST

X1.5PracticeE—Copper–CopperSulfate–16%Sulfuric

AcidTestisa15-htestinaboilingsolutionwiththetest

exposureintheboilingsolution,thespecimenisbent.

X1.5.1Thistestmaybeusedtoevaluatetheheattreatment

lsobeusedtoevaluate

theeffectivenessofstabilizingelementadditions(Cb,Ti,and

soforth)andreductionsincarboncontenttoaidinresisting

ughtproductsandweldmaterialof

austeniticstainlesssteelscanbeevaluatedbythistest.

X1.5.2PracticeEindicatessusceptibilitytointergranular

attackassociatedwiththeprecipitationofchromium-rich

carbidesin201,202,301,304,304L,316,316L,317,317L,

321,and347.

X1.5.3Itdoesnotdetectsusceptibilitytointergranular

attackassociatedwithsigmaphaseorend-graincorrosion,both

ofwhichhavebeenobservedonlyincertainnitricacid

environments.

X1.5.4TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestinginthecopper–copper

sulfate–16%sulfuricacidtest;notlistedin

Table4eitherhavenotbeenevaluatedforuseofPracticeA

withthecopper–coppersulfate-16%sulfuricacidtestorhave

beenfoundtogiveacceptabletestsintheetchtestwhilegiving

unacceptableresultsinthecopper–coppersulfate–16%sulfu-

ricacidtest,thuspassingmaterialthatshouldberejected.

PRACTICEF—COPPER–COPPERSULFATE–50%SULFURICACIDTEST

X1.6PracticeF—Copper–CopperSulfate–50%Sulfuric

AcidTestisa120-htestinaboilingsolutionthatcontains

metalliccopper.

X1.6.1Thistestdetectssusceptibilitytointergranularattack

associatedwiththeprecipitationofchromium-richcarbidesin

CF-3M,CF-8M,and316Ti.

X1.6.2Thistestdoesnotdetectsusceptibilitytoattack

associatedwithsigmaphase.

X1.6.3TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestinginthecopper–copper

sulfate–50%sulfuricacidtest;see

notlistedin

Table6eitherhavenotbeenevaluatedforuseofPracticeA

withthecopper–coppersulfate–50%sulfuricacidtestorhave

beenfoundtogiveacceptableresultsintheetchtestwhile

givingunacceptableresultsinthecopper–coppersulfate–50%

sulfuricacidtest,thuspassingmaterialthatshouldberejected.

REFERENCES

(1)Fororiginaldescriptionsoftheuseofetchstructureclassifications,

seeStreicher,M.A.,“ScreeningStainlessSteelsfromthe240-hNitric

AcidTestbyElectrolyticEtchinginOxalicAcid,”ASTMBulletin,No.

188,February1953,p.35;also“ResultsofCooperativeTesting

ProgramfortheEvaluationoftheOxalicAcidEtchTest,”ASTM

Bulletin,No.195,January1954,p.63.

(2)Fororiginaldescriptionsoftheboilingnitricacidtest,seeHuey,W.

R.,“CorrosionTestforResearchandInspectionofAlloys,”

Transactions,AmericanSocietyofSteelTreating,Vol18,1930,p.

1126;also,“ReportofSubcommitteeIVonMethodsofCorrosion

Testing,”Proceedings,ASTM,Vol33,PartI,1933,p.187.

(3)Streicher,M.A.,“TheoryandApplicationofEvaluationTestsfor

DetectingSusceptibilitytoIntergranularAttackinStainlessSteelsand

RelatedAlloys-ProblemsandOpportunities,”IntergranularCorro-

sionofStainlessAlloys,ASTMSTP656,rwalded.,ASTM,

1978,pp.3–84.

(4)Theuseofcoppertoacceleratetheintergranularcorrosionof

sensitizedausteniticstainlesssteelsincoppersulfate–sulfuricacid

wasfinthediscussionofapaperby

Brauns,E.,andPier,G.,StahlundEisen,Vol75,1955,p.579.

(5)Fororiginalevaluationofthecopper–coppersulfate–sulfuricacidtest,

seeScharfstein,L.R.,andEisenbrown,C.M.,“AnEvaluationof

AcceleratedStraussTesting,”ASTMSTP369,ASTM,1963,pp.

235–239.

(6)Subtleeffectsduetovariationsincoppersurfaceareas,galvanic

contact,condenserdesign,etc.,aredescribedbyHerbsleb,G.,and

Schwenk,W.,“UntersuchungenzurEinstellungdesRedoxpotentials

derStrausschenLösungmitZusatzvonMettalischemKupfer,”

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,

`

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,

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,

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,

,

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,

,

,

,

,

,

`

`

`

,

`

,

,

`

`

`

-

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-

`

,

,

`

,

,

`

,

`

,

,

`

-

-

-

19

A262−15

CorrosionScience,Vol7,1967,pp.501–511.

(7)Walker,W.L.,“VariationsintheEvaluationofASTMA262,Practice

E,Results(ASTMSubcommitteeA01.14RoundRobin),”Intergranu-

larCorrosionofStainlessAlloys,ASTMSTP656,rwald

ed.,ASTM,1978,pp.146–153.

(8)Brown,M.H.,“BehaviorofAusteniticStainlessSteelsinEvaluation

TestsfortheDetectionofSusceptibilitytoIntergranularCorrosion,”

Corrosion,Vol.30,January1974,pp.1–12.

BIBLIOGRAPHY

(1)Fororiginaldescriptionofferricsulfate-sulfuricacidtest,see

Streicher,M.A.,“IntergranularCorrosionResistanceofAustenitic

StainlessSteels:AFerricSulfate-SulfuricAcidTest,”ASTMBulletin,

No.229,April1958,pp.77–86.

(2)Fordetails,seeDeLong,W.B.,“TestingMultipleSpecimensof

StainlessSteelsinaModifiedBoilingNitricAcidTestApparatus,”

SymposiumonEvaluationTestsforStainlessSteels,ASTMSTP93,

ASTM,1950,p.211.

(3)SeeIndustrialandEngineeringChemistry,Vol17,1925,p.756;

also,“ficationsRecommendedby

CommitteeonAnalyticalReagents,”AmericanChemicalSociety,

March1941.

SUMMARYOFCHANGES

CommitteeA01hasidentifiedthelocationofselectedchangestothisstandardsincethelastissue(A262–14)

thatmayimpacttheuseofthisstandard.(ApprovedSept.1,2015.)

(1)Added

Note4to18.1,allowingotherglassjoints.

(2)RevisedApparatusrequirementsin40.1torefertoSection

18.

(3)Addednewsubsection38.1.2toPracticeEtoclarify

requiredheattreatmentthepriortoperformingtheRapid

Screening(Etch)Test.

Committee

A01hasidentifiedthelocationofselectedchangestothisstandardsincethelastissue(A262–13)

thatmayimpacttheuseofthisstandard.(ApprovedJuly1,2014.)

(1)AddednewSection

3onPurityofReagents.

(2)Addedfourreferenceddocuments.

(3)Re-wrotePracticeAintestmethodformat.

(4)Numberedtheun-numberednotesin

Figs.6and7.

(5)Re-wrotePracticeB;Renumberedsubsequentparagraphs,

notes,tables,andreferencestomatch.

(6)Correctedtheconstantin

Eq1.

(7)Re-wrotePracticeC;Renumberedsubsequentparagraphs,

notes,tables,andreferencestomatch.

(8)Removedreferencestothemultiplesampleapparatus.

(9)Re-wrotePracticeFintest-methodformat.

(10)Restrictedspecimentypetobasemetal.

(11)Addedproceduraltext.

(12)Revised45.1.

ASTMInternationaltakesnopositionrespectingthevalidityofanypatentrightsassertedinconnectionwithanyitemmentioned

fthisstandardareexpresslyadvisedthatdeterminationofthevalidityofanysuchpatentrights,andtherisk

ofinfringementofsuchrights,areentirelytheirownresponsibility.

Thisstandardissubjecttorevisionatanytimebytheresponsibletechnicalcommitteeandmustbereviewedeveryfiveyearsand

ifnotrevised,mmentsareinvitedeitherforrevisionofthisstandardorforadditionalstandards

mmentswillreceivecarefulconsiderationatameetingofthe

responsibletechnicalcommittee,eelthatyourcommentshavenotreceivedafairhearingyoushould

makeyourviewsknowntotheASTMCommitteeonStandards,attheaddressshownbelow.

ThisstandardiscopyrightedbyASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,

dualreprints(singleormultiplecopies)ofthisstandardmaybeobtainedbycontactingASTMattheabove

addressorat610-832-9585(phone),610-832-9555(fax),orservice@(e-mail);orthroughtheASTMwebsite

().PermissionrightstophotocopythestandardmayalsobesecuredfromtheCopyrightClearanceCenter,222

RosewoodDrive,Danvers,MA01923,Tel:(978)646-2600;/

20

2024年3月19日发(作者：綦颖然)

Designation:A262

−

15

StandardPracticesfor

DetectingSusceptibilitytoIntergranularAttackinAustenitic

StainlessSteels

1

ThisstandardisissuedunderthefixeddesignationA262;thenumberimmediatelyfollowingthedesignationindicatestheyearof

originaladoptionor,inthecaseofrevision,rinparenthesesindicatestheyearoflastreapproval.A

superscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.

mentofDefense.

*

1.1Thesepracticescoverthefollowingfivetests:

1.1.1PracticeA—OxalicAcidEtchTestforClassification

ofEtchStructuresofAusteniticStainlessSteels(Sections4to

13,inclusive),

1.1.2Practice

B—FerricSulfate-SulfuricAcidTestforDe-

tectingSusceptibilitytoIntergranularAttackinAustenitic

StainlessSteels(Sections14to25,inclusive),

1.1.3Practice

C—NitricAcidTestforDetectingSuscepti-

bilitytoIntergranularAttackinAusteniticStainlessSteels

(Sections26to36,inclusive),

1.1.4Practice

E—Copper–CopperSulfate–SulfuricAcid

TestforDetectingSusceptibilitytoIntergranularAttackin

AusteniticStainlessSteels(Sections37to46,inclusive),and

1.1.5Practice

F—Copper–CopperSulfate–50%Sulfuric

AcidTestforDetectingSusceptibilitytoIntergranularAttack

inMolybdenum-BearingAusteniticStainlessSteels(Sections

47to58,inclusive).

1.2

TheOxalicAcidEtchTestisarapidmethodof

identifying,bysimpleetching,thosespecimensofcertain

stainlesssteelgradesthatareessentiallyfreeofsusceptibility

tointergranularattackassociatedwithchromiumcarbide

pecimenswillhavelowcorrosionratesin

certaincorrosiontestsandthereforecanbeeliminated

(screened)fromtestingas“acceptable.”Theetchtestis

applicableonlytothosegradeslistedintheindividualhotacid

testsandclassifiesthespecimenseitheras“acceptable”oras

“suspect.”

1.3Theferricsulfate-sulfuricacidtest,thecopper–copper

sulfate–50%sulfuricacidtest,andthenitricacidtestarebased

onweightlossdeterminationsand,thus,provideaquantitative

contrast,thecopper–coppersulfate–16%sulfuricacidtestis

basedonvisualexaminationofbendspecimensand,therefore,

classifiesthespecimensonlyasacceptableornonacceptable.

1.4Thepresenceorabsenceofintergranularattackinthese

testsisnotnecessarilyameasureoftheperformanceofthe

estsdonot

provideabasisforpredictingresistancetoformsofcorrosion

otherthanintergranular,suchasgeneralcorrosion,pitting,or

stress-corrosioncracking.

N

OTE

1—SeeAppendixX1forinformationregardingtestselection.

1.5ThevaluesstatedinSIunitsaretoberegardedas

h-poundequivalentsareinparenthesesand

maybeapproximate.

1.6Thisstandarddoesnotpurporttoaddressallofthe

safetyconcerns,ifany,e

responsibilityoftheuserofthisstandardtoestablishappro-

priatesafetyandhealthpracticesanddeterminetheapplica-

ecific

hazardsstatementsaregivenin10.1,20.1.1,20.1.9,31.3,34.4,

53.1.1,and53.1.10.

2.

ReferencedDocuments

2.1ASTMStandards:

2

A370TestMethodsandDefinitionsforMechanicalTesting

ofSteelProducts

A380/A380MPracticeforCleaning,Descaling,andPassi-

vationofStainlessSteelParts,Equipment,andSystems

D1193SpecificationforReagentWater

E3GuideforPreparationofMetallographicSpecimens

2.2ASMECode:

3

ASMEBoiler&PressureVesselCode,SectionIX

2.3ACSSpecifications:

4

ReagentChemicals,SpecificationsandProcedures

ForreferencedASTMstandards,visittheASTMwebsite,,or

contactASTMCustomerServiceatservice@ualBookofASTM

Standardsvolumeinformation,refertothestandard’sDocumentSummarypageon

theASTMwebsite.

3

AvailablefromAmericanSocietyofMechanicalEngineers(ASME),ASME

InternationalHeadquarters,TwoParkAve.,NewYork,NY10016-5990,

.

4

AvailablefromAmericanChemicalSociety(ACS),1155SixteenthStreet,NW,

Washington,DC20036,

2

ThesepracticesareunderthejurisdictionofASTMCommitteeA01onSteel,

StainlessSteelandRelatedAlloysandarethedirectresponsibilityofSubcommittee

A01.14onMethodsofCorrosionTesting.

CurrenteditionapprovedSept.1,ally

eviouseditionapprovedin2014asA262–:

10.1520/A0262-15.

1

*ASummaryofChangessectionappearsattheendofthisstandard

Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,States

1

A262−15

2.4ISOStandard:

5

ISO3651-2DeterminationofResistancetoIntergranular

CorrosionofStainlessSteels—Part2:Ferritic,Austenitic,

andFerritic-Austenitic(Duplex)StainlessSteels—

CorrosionTestinMediaContainingSulfuricAcid

ofReagents

3.1PurityofReagents—Reagentgradechemicalsshallbe

otherwiseindicated,itisintendedthat

allreagentsconformtothespecificationsoftheCommitteeon

AnalyticalReagentsoftheAmericanChemicalSociety

6

where

suchspecifiradesmaybeused,

provideditisfirstascertainedthatthereagentisofsufficiently

highpuritytopermititsusewithoutlesseningtheaccuracyof

thetestresult.

3.2PurityofWater—Unlessotherwiseindicated,references

towatershallbeunderstoodtomeanreagentwaterasdefined

byTypeIVofSpecificationD1193.

PRACTICEA—OXALICACIDETCHTESTFOR

CLASSIFICATIONOFETCHSTRUCTURESOF

AUSTENITICSTAINLESSSTEELS(

1)

7

4.1TheOxalicAcidEtchTestisusedforacceptanceof

wroughtorcastausteniticstainlesssteelmaterialbutnotfor

262PracticeAasastand-alone

testmayrejectmaterialthattheapplicablehotacidtestwould

findacceptable;suchuseisoutsidethescopeofthispractice.

4.2Thistestisintendedtobeusedinconnectionwithother

evaluationtestsdescribedinthesepracticestoprovidearapid

methodforidentifyingqualitativelythosespecimensthatare

certaintobefreeofsusceptibilitytorapidintergranularattack

ecimenshavelowcorrosionratesin

thevarioushotacidtestswhichrequirefrom15to240hof

pecimensareidentifiedbymeansoftheir

etchstructures,whichareclassifiedaccordingtothecriteria

giveninSection

11.

4.3TheOxalicAcidEtchTestmaybeusedtoscreen

specimensintendedfortestinginPracticeB—FerricSulfate-

SulfuricAcidTest,PracticeC—NitricAcidTest,Practice

E—Copper-CopperSulfate–16%SulfuricAcidTest,andPrac-

ticeF—Copper-CopperSulfate–50%SulfuricAcidTest.

4.4Eachoftheseotherpracticescontainsatableshowing

whichclassificationsofetchstructuresonagivenstainless

steelgradeareequivalenttoacceptableorsuspectperformance

enshavingacceptableetch

ens

havingsuspectetchstructuresmustbetestedinthespecified

hotacidsolution.

AvailablefromInternationalOrganizationforStandardization(ISO),1,

laVoie-Creuse,CP56,CH-1211Geneva20,Switzerland,.

6

ForsuggestionsonthetestingofreagentsnotlistedbytheAmericanChemical

Society,seeAnalarStandardsforLaboratoryChemicals,BDHLtd.,Poole,Dorset,

U.K.,andtheUnitedStatesPharmacopeiaandNationalFormulary,-

copeialConvention,Inc.(USPC),Rockville,MD.

7

Theboldfacenumbersinparenthesesrefertoalistofreferencesattheendof

thisstandard.

5

4.5Therearetwoclassesofspecimenstobeconsidered:

basemetal,andprocess-affectedmetal.

4.5.1Process-affectedmetalcontainsanyconditionthat

affectsthecorrosionpropertiesofthematerialinanon-uniform

way,suchas(butnotlimitedto)welds;ed,or

oxidizedsurfaces;mechanicaldeformation;andareasaffected

talhasnoneoftheseconditions.

4.5.2BecausePracticesB,C,andFinvolveimmersingthe

entirespecimenandaveragingthemasslossoverthetotal

specimenarea,andbecausewelding,carburization,mechanical

deformation,andthelikeaffectonlypartofaspecimen,the

presenceofprocess-affectedmetalinaspecimencanaffectthe

testresultinanunpredictablewaydependingonthepropor-

tionsoftheareaaffected.

4.5.3Ifthepresenceoftheseorotherlocalizedconditionsis

aconcerntothepurchaser,thenteststhatdonotaveragethe

masslossoverthetotalspecimensurfacearea,suchasPractice

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

Sulfate–SulfuricAcidTestforDetectingSusceptibilityto

IntergranularAttackinAusteniticStainlessSteels,shouldbe

considered.

yofPractice

5.1Aspecimenrepresentativeofthematerialtobeevalu-

atedispolishedtoaspecifiedfinishandover-etchedusing

hedspecimenisthen

hedstruc-

tureiscomparedwithreferencephotographstodetermine

tmaterial

isthensubjectedtothespecifiedhotacidimmersiontest.

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`

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,

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,

,

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ficanceandUse

6.1Useoftheetchtestallowsrapidacceptanceofspecific

lotsofmaterialwithouttheneedtoperformtime-consuming

andcostlyhotacidimmersiontestsonthoselots.

tus

7.1EtchingCell:

7.1.1Anetchingcellmaybeassembledusingcomponents

atively,acommercial

electropolisher/etcher(asusedformetallographicsample

preparation)maybeusedforsmallspecimensprovidedthe

currentdensityrequirementof

10.2ismet.

7.1.2SourceofDirectCurrent—Battery,generator,orrec-

tifiercapableofsupplyingabout15Vand20A.

7.1.3Ammeter—Fordirectcurrent;usedtomeasurethe

currentonthespecimentobeetched.

7.1.4VariableResistance—Usedtocontrolthecurrenton

thespecimentobeetched.

7.1.5Cathode—Astainlesssteelcontainer,forexample,a

1-L(1-qt)stainlesssteelbeaker.

7.1.5.1AlternateCathode—Apieceofflatstainlesssteelat

leastaslargeasthespecimensurface.

7.1.6ElectricalClamp—Toholdthespecimentobeetched

andtocompletetheelectricalcircuitbetweenthespecimenand

thepowersourcesuchthatthespecimenistheanodeofthe

cell.

2

A262−15

7.1.7Thepowersource,resistor,andammetermustbesized

10.2.1.2Adjustthevariableresistanceuntiltheammeter

appropriatelyforprovidingandcontrollingthecurrentas

readinginamperesisequaltothetotalimmersedareaofthe

specifiedin10.2ofthispractice.

specimeninsquarecentimetres.

7.1.8Asdescribed,theelectrolytecontaineristhecathode;

itmaybeastainlesssteelbeakerorfabricatedfromstainless

10.3Ayellow-greenfilmisgraduallyformedonthecath-

steelsuchasbyweldingasectionoftubeorpipetoaflatplate

is

atively,theelectrolytecontainermaybeglass

occurs,removethefilmbyrinsingtheinsideofthestainless

(orothernon-conducting,corrosionresistingmaterial)inlieu

steelbeaker(orthesteelusedasthecathode)withanacidsuch

ofastainlesssteelcontainer,andthecathodemaybeaflatplate

as30%HNO

3

.

lattercase,theflat

10.4Thetemperatureoftheetchingsolutiongradually

surfaceofthecathodemustbeatleastaslargeas,facing,and

etemperaturebelow50°C.

approximatelycenteredon,thepreparedsurfaceofthespeci-

be

onfigurationsoftheelectrodesmightnotprovide

cooledintapwaterwhiletheotherisusedforetching.

ase,the

10.4.1Therateofheatingdependsonthetotalcurrent

sizeandshapeofthespecimendictatethesizeandconstruction

(ammeterreading)ore,keep

theareatobeetchedassmallaspossiblewhileatthesametime

overridingprincipleisthattheetchneedstobeuniformover

meetingtherequirementsofdesirableminimumareatobe

thesurfacetobeexamined.

etched.

7.2MetallurgicalMicroscope—Forexaminationofetched

10.5Avoidimmersingtheclampholdingthespecimenin

microstructuresat250to500diameters.

theetchingsolution.

tsandMaterials

10.6Rinsing—Followingetching,rinsethespecimenthor-

oughlyinhotwaterandtheninacetoneoralcoholtoavoid

8.1EtchingSolution(10%)—Dissolve100gofreagent

crystallizationofoxalicacidontheetchedsurfaceduring

gradeoxalicacidcrystals(H

2

C

2

O

4

·2H

2

O)in900mLof

drying.

tilallcrystalsaredissolved.

8.1.1AlternateEtchingSolution(See10.7)—Dissolve100g

10.7Itmaybedifficulttorevealthepresenceofstep

ofreagentgradeammoniumpersulfate((NH

structuresonsomespecimenscontainingmolybdenum(AISI

4

)

2

S

tildissolved.

2

O

8

)in

900

316,316L,317,317L),whicharefreeofchromiumcarbide

sensitization,

ngandTestSpecimens

cases,analternateelectrolyteofammoniumpersulfatemaybe

9.1Thespecifiedhotacidtestprovidesinstructionsfor

usedinplaceofoxalicacid.(See

8.1.1.)Anetchfor5or10

samplingandforspecimenpreparationsuchasasensitization

minat1A/cm

2

inasolutionatroomtemperaturereadily

onalinstructionsspecifictoPracticeA

developsstepstructuresonsuchspecimens.

follow:

ficationofEtchStructures

9.2Thepreferredspecimenisacross-sectionincludingthe

chfinishingof

11.1Examinetheetchedsurfaceonametallurgicalmicro-

theproductsurfaceshouldbeperformedasisrequiredto

scopeat250×to500×forwroughtsteelsandatabout250×for

removeforeignmaterial.

caststeels.

9.3Wheneverpractical,useacross-sectionalareaof1cm

2

11.2Examinetheetchedcross-sectionalareasthoroughly

ross-sectionaldimensionislessthan1cm,

bycompletetraversefrominsidetooutsidediametersofrods

thentheotherdimensionofthecross-sectionshouldbea

andtubes,fromfacetofaceonplates.

thdimensionsoftheproductare

11.2.1Microscopicalexaminationofaspecimenshallbe

lessthan1cm,useafullcrosssection.

madeonmetalunaffectedbycold-working,carburization,

welding,ftheseconditionsarefound,note

9.4Polishing—Onalltypesofmaterials,polishcrosssec-

theirpresenceinthereport.

tionalsurfacesthroughCAMI/ANSI600[FEPA/ISOP1200]in

accordancewithGuide

E3priortoetchingandexamination.

11.3Classifytheetchstructuresintothefollowingtypes

Notallscratchesneedtoberemoved.

(

Note2):

11.3.1StepStructure(Fig.1)—Stepsonlybetweengrains,

ure

noditchesatgrainboundaries.

10.1(Warning—Etchingshouldbecarriedoutundera

11.3.2DualStructure(Fig.2)—Someditchesatgrain

,whichisrapidlyevolvedattheelectrodes

boundariesinadditiontosteps,butnosinglegraincompletely

withsomeentrainmentofoxalicacid,ispoisonousand

surroundedbyditches.

irritatingtomucousmembranes.)

11.3.3DitchStructure(

Fig.3)—Oneormoregrainscom-

pletelysurroundedbyditches.

10.2Etchthepolishedspecimenat1A/cm

2

for1.5min.

11.3.4IsolatedFerrite(Fig.4)—Observedincastingsand

10.2.1Toobtainthecorrectspecifiedcurrentdensity:

etweenaustenitematrixandferritepools.

10.2.1.1Measurethetotalimmersedareaofthespecimento

11.3.5InterdendriticDitches(

Fig.5)—Observedincastings

beetchedinsquarecentimetres.

terconnectedditches.

3

-

-

-

`

,

,

`

,

`

,

,

`

,

,

`

-

`

-

`

`

`

,

,

`

,

`

`

`

,

,

,

,

,

,

`

,

,

`

,

`

`

,

`

`

,

`

,

`

-

-

A262−15

FIG.2DualStructure(250×)(SomeDitchesatGrainBoundaries

inAdditiontoSteps,butNoOneGrainCompletelySurrounded)

FIG.4IsolatedFerritePools(250×)(ObservedinCastingsand

etweenAusteniteMatrixandFerritePools)

11.3.6End-GrainPittingI(Fig.6)—Structurecontainsa

fewdeepend-grainpitsalongwithsomeshallowetchpitsat

500×.(Ofimportanceonlywhenthenitricacidtestisused.)

11.3.7End-GrainPittingII(Fig.7)—Structurecontains

numerous,deepend-grainpitsat500×.(Ofimportanceonly

whennitricacidtestisused.)

N

OTE

2—Allphotomicrographsweremadewithspecimensthatwere

etchedunderstandardconditions:10%oxalicacid,roomtemperature,

1.5minat1A/cm

2

.

11.4Theevaluationofetchstructurescontainingonlysteps

andofthoseshowinggrainscompletelysurroundedbyditches

ineveryfisthat

appeartobedualstructures,moreextensiveexaminationis

requiredtodetermineifthereareanygrainscompletely

circledgrainisfound,classifythesteelasa

ditchstructure.

11.4.1Onstainlesssteelcastings(alsoonweldmetal),the

stepsbetweengrainsformedbyelectrolyticoxalicacidetching

tendtobelessprominentthanthoseonwroughtmaterialsor

4

-

-

`

,

`

,

`

`

,

`

`

,

`

,

,

`

,

,

,

,

,

,

`

`

`

,

`

,

,

`

`

`

-

`

-

`

,

,

`

,

,

`

,

`

,

,

`

-

-

-

FIG.1StepStructure(500×)(StepsBetweenGrains,NoDitches

atGrainBoundaries)

FIG.3DitchStructure(500×)(OneorMoreGrainsCompletely

SurroundedbyDitches)

A262−15

FIG.5InterdendriticDitches(250×)(ObservedinCastingsand

terconnectedDitches)

N

OTE

1—Thisoragreaterconcentrationofendgrainpitsat500×(using

standardetchingconditions)indicatesthatthespecimenmustbetested

whenscreeningisfornitricacidtest.

FIG.7EndGrainPittingII(500×)

structures,specimenshavingasmuchormoreendgrainpitting

thanthatshownin

Fig.7cannotbesafelyassumedtohavelow

nitricacidratesandshouldbesubjectedtothenitricacidtest

wheneveritisspecifiarp,deeppitsshouldnotbe

confusedwiththeshallowpitsshownin

Figs.1and6.

tchStructureClassifications

12.1Theuseoftheseclassificationsdependsonthehotacid

corrosiontestforwhichstainlesssteelspecimensarebeing

screenedbyetchinginoxalicacidandisdescribedineachof

thepractices.

ionandBias

13.1PrecisionandBias—Noinformationispresentedabout

eithertheprecisionorbiasofPracticeA—OxalicAcidEtch

TestforclassificationofEtchStructuresofAusteniticStainless

Steelssincethetestresultisnonquantitative.

N

OTE

1—Todifferentiatebetweenthetypesofpits,useamagnification

of500×swhichnow

appearcompletelyblackareendgrainpits.

FIG.6EndGrainPittingI(500×)(AFewDeepEndGrainPits

(See1inFigure)andShallowEtchPits(2))

PRACTICEB—FERRICSULFATE–SULFURIC

ACIDTESTFORDETECTINGSUSCEPTIBILITY

TOINTERGRANULARATTACKIN

AUSTENITICSTAINLESSSTEELS(

2)

14.1Thispracticedescribestheprocedureforconducting

theboiling120-hferricsulfate–50%sulfuricacidtestwhich

measuresthesusceptibilityofausteniticstainlesssteelsto

intergranularattack.

14.2Thepresenceorabsenceofintergranularattackinthis

testisnotnecessarilyameasureoftheperformanceofthe

tdoesnot

provideabasisforpredictingresistancetoformsofcorrosion

5

r,anysusceptibilitytointergranular

attackisreadilydetectedbypronouncedditches.

11.4.2Somewroughtspecimens,especiallyfrombarstock,

epitsaresharpand

sodeepthattheyappearblack(Fig.7)itispossiblethatthe

specimenmaybesusceptibletoendgrainattackinnitricacid

ore,eventhoughthegrainboundariesallhavestep

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

A262−15

otherthanintergranular,suchasgeneralcorrosion,pitting,or

stress-corrosioncracking.

yoftheFerricSulfate-SulfuricAcidPractice

B

15.1Aspecimenrepresentativeofthematerialtobeevalu-

atedisimmersedinaboilingsolutionofferricsulfateand

sulfuricacidforaspecifiultingmasslossis

convertedtoacorrosionrate,whichiscomparedtoaspecified

maximumvaluetodeterminewhetherthematerialhasthe

resistancetoattackexpectedofthegradeofmaterialbeing

tested.

ficanceandUse

16.1Theferricsulfate-sulfuricacidtestdetectssusceptibil-

itytointergranularattackassociatedprimarilywithchromium

carbideprecipitateinunstabilizedausteniticstainlesssteels,

andtointergranularattackassociatedwithsigmaphase.

16.2Thecorrosionpotentialoftheferricsulfate-sulfuric

acidtesthasbeenreportedas0.6Vversusastandardcalomel

electrode(SCE),ascomparedwith0.75to1.0VforPracticeC,

and0.1VforPracticesEandF.(

3)

N

OTE

3—Ahighercorrosionpotentialindicatesmoreseverelyoxidizing

conditions.

17.3Ignore“process-affected”areas(seeSection

21);ap-

plicationoftheferricsulfate-sulfuricacidtesttoprocess-

affectedareasiscurrentlyoutsidethescopeofPracticeB.

17.4Corrosiontestspecimenshavingacceptableetchstruc-

turesintheOxalicAcidEtchTestwillbeessentiallyfreeof

specimensareacceptablewithouttestingintheferricsulfate-

cimenshavingsuspectetchstructures

shallbetestedintheferricsulfate-sulfuricacidtest.

tus

18.1Theapparatusisillustratedin

Fig.8.

N

OTE

4—Othergroundglassjoints,suchasthe45/40jointmayalsobe

used.

creeningTest

17.1Beforetestingintheferricsulfate-sulfuricacidtest,

specimensofcertaingradesofstainlesssteels(seeTable1)

maybegivenarapidscreeningtestinaccordancewith

proceduresgiveninPracticeA,OxalicAcidEtchTestfor

ClassificationofEtchStructuresofAusteniticStainlessSteels.

Preparation,etching,andtheclassificationofetchstructures

ofetchstructureevaluationsin

connectionwiththeferricsulfate-sulfuricacidtestisspecified

in

Table1.

17.2Heattreatthematerialinaccordancewith22.1priorto

performingtheetchtest.

18.1.1AnAllihncondenserwithaminimumoffourbulbs

andwithagroundglassjointtomatchthatoftheflask.

18.1.1.1Substitutionsforthiscondenserorflaskarenot

fically,thecold-fingertypeofcondenserwith

standardErlenmeyerflionrates

obtainedusingthecold-fingertypeofcondenserarelowerthan

thoseobtainedusingtheAllihntypeofcondenserwhetherdue

tolossofvaporortohigheroxygencontentinthesolutionor

wercorrosionratesleadtoacceptanceofmaterial

thatshouldberejected.

18.1.2A1-LErlenmeyerflaskwithagroundglassjointto

flaskopeninglimitsthesize

ofthespecimen;alargeropeningisdesirable.

TABLE1UseofEtchStructureClassificationsfromtheOxalic

AcidEtchTestwithFerricSulfate-SulfuricAcidTest

A

Grade

304

304L

316

316L

317

317L

CF-3

CF-8

CF-3M

CF-8M

A

AcceptableEtch

Structures

Step,

Step,

Step,

Step,

Step,

Step,

Step,

Step,

Step,

Step,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

dual,

endgrain,I&II

endgrain,I&II

endgrain,I&II

endgrain,I&II

endgrain,I&II

endgrain,I&II

isolatedferritepools

isolatedferritepools

isolatedferritepools

isolatedferritepools

Suspect

EtchStructures

B

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch,

Ditch,

Ditch,

Ditch,

interdendritic

interdendritic

interdendritic

interdendritic

ditches

ditches

ditches

ditches

GradesnotlistedinthistableeitherhavenotbeenevaluatedforuseofPractice

AwithPracticeBorhavebeenfoundtogiveacceptableresultsintheetchtest

attercasePracticesAwould

passmaterialthatshouldhavebeensubjectedtotheferricsulfate-sulfuricacid

test.

B

Specimenshavingthesestructuresshallbetestedintheferricsulfate-sulfuric

acidtest.

FIG.8ApparatusforFerricSulfate-SulfuricAcidTest

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

6

A262−15

18.1.3Glasscradle(Note5)—Canbesuppliedbyaglass-

containsanyconditionthataffectsthecorrosionpropertiesof

besizedsoastofit,withthespecimen,

thematerialinanon-uniformway,suchas(butnotlimitedto)

throughtheflbedesignedtoallowfree

welds;ed,oroxidizedsurfaces;mechanical

flowofthetestingsolutionaroundthespecimen.

deformation;talhasnone

N

OTE

5—Otherequivalentmeansofspecimensupport,suchasglass

oftheseconditions.

hooksorstirrups,mayalsobeused.

21.1.2ThePracticeBtestinvolvesimmersingtheentire

18.1.4BoilingChips—Usedtopreventbumping.

specimenandaveragingthemasslossovertheentiresurfaceof

18.1.5HighVacuumSiliconeGrease—Forthegroundglass

g,carburization,mechanicaldeformation,

joint.

andthelike,affectonlypartofaspecimen.

18.1.6Hotplate,capableofprovidingheatforcontinuous

21.1.3Themasslossratefromprocess-affectedmetalis

boilingofthesolution.

expectedtodifferfromthatfrombasemetal;thepresenceof

18.1.7Ananalyticalbalancecapableofweighingtothe

process-affectedmetalinaspecimenwillaffectthecalculated

nearest0.001g.

testresultinanunpredictableway.

21.1.4Ifthepresenceoftheseorotherlocalizedconditions

N

OTE

6—Duringtesting,thereissomedepositionofironoxidesonthe

upperpartoftheErlenmeyerflnbereadilyremoved,aftertest

isaconcerntothepurchaser,thenteststhatdonotaveragethe

completion,byboilingasolutionof10%hydrochloricacidintheflask.

masslossoverthetotalspecimensurfacearea,suchasPractice

18.1.8Desiccator—Forstorageofpreparedspecimensprior

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

totesting.

Sulfate–16%SulfuricAcidTestforDetectingSusceptibilityto

IntergranularAttackinAusteniticStainlessSteels,shouldbe

tsandMaterials

softhetestandacceptancecriteriashallbe

19.1FerricSulfateHydrate(Fe

asagreedbythepurchaserandproducer.

(SO

2

(SO

4

)

3

·xH

2

O),about75%

(Fe

24

)

21.2Unlessotherwisespecifiedbythepurchaser,thepro-

Ferric

3

)bymass.

19.1.1sulfateisaspecificadditivethatestablishes

ceduresforobtainingrepresentativebasemetalsamples,for

tutionsarenot

removingthespecimensfromthesamples,andthenumberof

permitted.

specimensshallbeatthediscretionoftheproducer.

19.2SulfuricAcid(H

2

(SO)

4

),95.0to98.0%bymass.

ationofTestSpecimens

Sulfate-SulfuricAcidTestSolution

22.1Heattreatextra-lowcarbonandstabilizedgradesat

20.1Prepare600mLof50%(49.4to50.9%)solutionas

650to675°C(1200to1250°F),whichistherangeof

follows:

maximumcarbideprecipitation,gthof

20.1.1(Warning—Protecttheeyesanduserubbergloves

timeofheating,andthemethodofsubsequentcoolingusedfor

hetestflaskunderahood.)

thissensitizingtreatmenttogetherwiththecorresponding

20.1.2First,measure400.0mLofTypeIVreagentwater

maximumpermissiblecorrosionrateshallbeasagreedbe-

andpourintotheErlenmeyerflask.

tweenthematerialproducerandpurchaser.

20.1.3Thenmeasure236.0mLofreagent-gradesulfuric

N

OTE

8—Themostcommonlyusedsensitizingtreatmentis1hat

acidslowlyandwithconstantstirringtothe

675°C(1250°F).

waterintheErlenmeyerflasktoavoidboilingbytheheat

evolved.

22.2Prepare

2

thespecimens,eachhavingatotalsurfacearea

of5to20cm.

N

OTE

7—Lossofvaporresultsinconcentrationoftheacid.

22.3Wherefeasiblefortheproductform,grindallthe

20.1.4Weigh25gofreagent-gradeferricsulfatetothe

specimensurfacesusingCAMI/ANSI120[FEPA/ISOP120]

nearest0.1gandaddtothesulfuricacidsolution.

paper-backed,wetordry,closedcoatedabrasivepaper,with

20.1.5Dropboilingchipsintotheflask.

sivepaperisuseddry,polishslowly

20.1.6Lubricategroundglassjointwithsiliconegrease.

seabrasiveswithgrindingaids;

20.1.7Coverflaskwithcondenserandcirculatecooling

somegrindingaidscontainfluoridesthatcanaffectthe

water.

measuredcorrosionrate.

20.1.8Boilthesolutionuntilallferricsulfateisdissolved

(seeNote7).

22.4Removealltracesofoxidescaleandheattintformed

20.1.9(Warning—Ithasbeenreportedthatviolentboiling

lethatcannotberemovedby

portanttoensurethat

grinding(forexample,instampednumbers)mayberemoved

theconcentrationofaciddoesnotincreaseandthatanadequate

byusingoneofthepicklingsolutionsdescribedinPractice

numberofboilingchips(whichareresistanttoattackbythe

A380/A380M,TableA1.1.(Residualoxidescalecausesgal-

testsolution)arepresent.)

vanicactionandconsequentactivationinthetestsolution.)

22.5Measurethespecimens,includingtheinnersurfacesof

ng

anyholes,tothenearest0.05mm(0.001in.)andcalculatethe

21.1Obtainandprepareonlybasemetalsamples.

totalexposedarea.

21.1.1Therearetwoclassesofspecimenstobeconsidered:

22.6Degreasethespecimensusingsuitablenonchlorinated

basemetal,s-affectedmetal

agents,suchassoapandlukewarmwater,

7

-

-

-

`

,

,

`

,

`

,

,

`

,

,

`

-

`

-

`

`

`

,

,

`

,

`

`

`

,

,

,

,

,

,

`

,

,

`

,

`

`

,

`

`

,

`

,

`

-

-

A262−15

he

specimensinadesiccatoruntilthetestistobeperformed.

ure

23.1Ifthetestsolutionisnotalreadyboiling,bringitto

boiling.

23.1.1Keeptheflaskcoveredwiththecondenser(with

coolingwaterflowing)exceptwheninsertingorremoving

specimens.(SeeNote7.)

23.2Turnofftheheatsourceandallowtheboilingto

subside.

23.3Placespecimensinglasscradles.

23.4Uncovertheflask.

23.5Insertthespecimens.

23.6Replacethecondenserimmediately,restorecooling

waterflow,andturnontheheatsource.

23.7Marktheliquidlevelontheflasktoprovideacheckon

vaporloss,

thereisanappreciablechangeinthelevel,repeatthetestwith

freshsolutionandregroundandreweighedspecimens.

23.8Continuetheimmersionofthespecimensforatotalof

120h(fivedays),thenremovethespecimens,rinseinwateror

acetone,anddry.

23.9Weighthespecimensandsubtractthenewweights

fromoriginalweights.

r,if

preliminaryresultsaredesired,thespecimenscanberemoved

atanytimeforweighing.

23.11Changestothesolutionduringthe120-htestperiods

arenotnecessary.

23.12Ifthecorrosionrateisextraordinarilyhigh,asevi-

dencedbyachangeinthecolor(fromyellowtogreen)ofthe

solution,additionalferricsulfateinhibitormayneedtobe

otalweightlossofallthe

specimensinaflaskexceeds2g,moreferricsulfatemustbe

added.(Duringthetest,ferricsulfateisconsumedatarateof

10gforeach1gofdissolvedstainlesssteel.)

number(3or4)islimitedonlybythenumberofglasscradles

thatcanbefittedintotheflask.

ationandReport

24.1Theeffectoftheacidsolutiononthematerialis

measuredbydeterminingthelossofweightofthespecimen.

Thecorrosionratesshouldbereportedasmillimetresof

penetrationpermonth(

Note9),calculatedasfollows:

Millimetrepermonth5

~

73053W

!

/

~

A3t3d

!

(1)

forchromium-nickelsteels,d=7.9g/cm

3

forchromium-nickel-molybdenumsteels,d=8.00g/cm

3

N

OTE

9—Conversionfactorstoothercommonlyusedunitsforcorro-

sionratesareasfollows:

Millimetrespermonth×0.04=inchespermonth

Millimetrespermonth×0.47=inchesperyear

Millimetrespermonth×12=millimetresperyear

Millimetrespermonth×472=milsperyear

Millimetrespermonth×1000×density/3=milligramspersquare

decimetreperday

Millimetrespermonth×1.39×density=gramspersquaremetreperhour

ionandBias

25.1Precision—TheprecisionofPracticeBisbeingdeter-

mined.

25.2Bias—Thispracticehasnobiasbecausetheresistance

tointergranularcorrosionisdefinedonlyintermsofthis

practice.

PRACTICEC—NITRICACIDTESTFOR

DETECTINGSUSCEPTIBILITYTO

INTERGRANULARATTACKIN

AUSTENITICSTAINLESSSTEELS

26.1Thispracticedescribestheprocedureforconducting

theboilingnitricacidtest(

2)asemployedtomeasurethe

relativesusceptibilityofausteniticstainlesssteelstointer-

granularattack.

26.2Thepresenceorabsenceofintergranularattackinthis

testisnotnecessarilyameasureoftheperformanceofthe

materialinothercorrosiveenvironments;inparticular,itdoes

notprovideabasisforpredictingresistancetoformsof

corrosionotherthanintergranular,suchasgeneralcorrosion,

pitting,orstress-corrosioncracking.

yofTestMethodC,theNitricAcidTest

27.1Aspecimenrepresentativeofthematerialtobeevalu-

atedisimmersedinaboilingsolutionofnitricacidfora

specifiultingmasslossisconvertedtoa

corrosionrate,whichiscomparedtoaspecifiedmaximum

valuetodeterminewhetherthematerialhastheresistanceto

attackexpectedofthegradeofmaterialbeingtested.

ficanceandUse

28.1Thenitricacidtestdetectssusceptibilitytorapid

intergranularattackassociatedwithchromiumcarbideprecipi-

tate

28.2Thecorrosionpotentialofthenitricacidtest(Practice

C)hasbeenreportedas0.75to1.0Vversusastandardcalomel

electrodeascomparedwith0.6VforPracticeB,and0.1Vfor

PracticesEandF.(

3)

N

OTE

10—Highercorrosionpotentialindicatesmoreseverelyoxidizing

hcorrosionpotentialofthenitricacidtestsuggeststhat

itshouldbeinvokedonlywhenthematerialisdestinedfornitricacid

service.

where:

t=timeofexposure,h,

A=area,cm

2

,

W=weightloss,g,and

d=density,g/cm

3

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

creeningTest

29.1Beforetestinginthenitricacidtest,specimensof

certaingradesofstainlesssteel,asgiveninTable2,maybe

8

A262−15

TABLE2UseofEtchStructureClassificationfromOxalicAcid

EtchTestwithNitricAcidTest

A

Grade

AISI304

AISI304L

ACICF-8

ACICF-3

A

AcceptableEtch

Structures

Step,dual,endgrain

Step,dual,endgrain

Step,dual,isolatedferrite

Step,dual,isolatedferrite

I

I

pools

pools

SuspectEtch

Structures

B

Ditch,endgrainII

Ditch,endgrainII

Ditch,interdendriticditches

Ditch,interdendriticditches

30.3Heater—Ameansforheatingthetestsolutionsandof

trically

heatedhotplateissatisfactoryforthispurpose.

30.4Balance—Ananalyticalbalancecapableofweighing

toatleastthenearest0.001g.

30.5Desiccator—Forstorageofpreparedspecimensprior

totesting.

AcidTestSolution

31.1Thetestsolutionshallbe65.060.2weight%asnitric

aciddeterminedbyanalysis.

31.2Preparethissolutionbyaddingreagentgradenitric

acid(HNO

3

Table3)toreagentwaterattherateof108mLof

reagentwaterperlitreofreagentnitricacid.

31.3(Warning—Protecttheeyesanduserubberglovesfor

hetestflaskunderahood.)

31.4ThenitricacidusedshallconformtotheAmerican

ChemicalSocietySpecificationsforReagentChemicalsand

theadditionalrequirementsofthistestmethodasshownin

Table3.

ng

32.1Obtainandprepareonlybasemetalsamples.

32.1.1Therearetwoclassesofspecimenstobeconsidered:

basemetal,s-affectedmetal

containsanyconditionthataffectsthecorrosionpropertiesof

thematerialinanon-uniformway,suchas(butnotlimitedto)

welds;ed,oroxidizedsurfaces;mechanical

deformation;talhasnone

oftheseconditions.

32.1.2ThePracticeCtestinvolvesimmersingtheentire

specimenandaveragingthemasslossovertheentiresurfaceof

g,carburization,mechanicaldeformation,

andthelike,affectonlypartofaspecimen.

32.1.3Themasslossratefromprocess-affectedmetalis

expectedtodifferfromthatfrombasemetal;thepresenceof

process-affectedmetalinaspecimenwillaffectthecalculated

testresultinanunpredictableway.

32.1.4Ifthepresenceoftheseorotherlocalizedconditions

isaconcerntothepurchaser,thenteststhatdonotaveragethe

masslossoverthetotalspecimensurfacearea,suchasPractice

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

Sulfate–SulfuricAcidTestforDetectingSusceptibilityto

TABLE3NitricAcidCompositionLimits

Minimum

NitricAcid(HNO

3

),

masspercent

Ash,ppm

ChlorideasCl,ppm

Sulfate,as(SO

4

),ppm

Arsenic(As),ppm

Heavymetals,asPb,

ppm

Iron,(Fe),ppm

Additionallimitsper

PracticesA262

Fluorine(F),ppm

Phosphate(PO

4

),ppm

69.0

{

{

{

{

{

{

Maximum

71.0

5

0.5

1

0.01

0.2

0.2

GradesnotlistedinthistableeitherhavenotbeenevaluatedforuseofPractice

AwithPracticeBorhavebeenfoundtogiveacceptableresultsintheetchtest

attercasePracticeAwould

passmaterialthatshouldhavebeensubjectedtotheferricsulfate-sulfuricacid

test.

B

Specimenshavingthesestructuresshallbetestedinthenitricacidtest.

givenarapidscreeningtestinaccordancewithprocedures

giveninPracticeA,OxalicAcidEtchTestforClassificationof

ofthe

etchstructureevaluationsinconnectionwiththenitricacidtest

isspecifiedinTable2.

29.2Heattreatthematerialinaccordancewith33.1priorto

performingtheetchtest.

29.3Ignore“process-affected”areas,ifany(seeSection

32);applicationofthenitricacidtesttoprocess-affectedareas

iscurrentlyoutsidethescopeofPracticeC.

29.4Corrosiontestspecimenshavingacceptableetchstruc-

turesintheOxalicAcidEtchTestwillbeessentiallyfreeof

intergranularattackinthenitricacidtest;suchspecimensare

cimens

havingsuspectetchstructuresshallbetestedinthenitricacid

test.

tus

30.1Container—A1-LErlenmeyerflaskequippedwitha

coldfinger-typecondenser,asillustratedin

Fig.9.

30.2SpecimenSupports—Glasshooks,stirrups,orcradles

forsupportingthespecimensintheflaskfullyimmersedatall

timesduringthetestandsodesignedthatspecimenstestedin

thesamecontainerdonotcomeincontactwitheachother.

{

{

1

0.2

FIG.9FlaskandCondenserforNitricAcidTest

9

-

-

`

,

`

,

`

`

,

`

`

,

`

,

,

`

,

,

,

,

,

,

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`

`

,

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,

,

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`

-

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,

,

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,

,

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,

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,

,

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-

-

-

A262−15

IntergranularAttackinAusteniticStainlessSteels,shouldbe

lossofthespecimenduringtheearlypartofthetest.

softhetestandacceptancecriteriashallbe

asagreedbythepurchaserandproducer.

33.6Thestandardtestistotestonlyonespecimenofeach

r,incaseofdispute,theuse

32.2Unlessotherwisespecifiedbythepurchaser,thepro-

ofatleasttwospecimensforcheckpurposesisrecommended.

ceduresforobtainingrepresentativebasemetalsamples,for

removingthespecimensfromthesamples,andthenumberof

ure

specimensshallbeatthediscretionoftheproducer.

34.1Useasufficientquantityofthenitricacidtestsolution

32.3Whenspecimensarecutbyshearing,theshearededges

tocover

2

thespecimensandtoprovideavolumeofatleast20

shallberefinishedbymachiningorgrindingpriortotesting.

mL/cm(125mL/in.

2

)ly,a

volumeofabout600mLisused.

ationofTestSpecimens

34.2Useaseparatecontainerforeachtestspecimen.

33.1Heattreatextra-lowcarbonandstabilizedgradesat

34.2.1Asmanyasthreespecimensmaybetestedinthe

650to675°C(1200to1250°F),whichistherangeof

samecontainerprovidedthattheyallareofthesamegradeand

maximumcarbideprecipitation,gthof

allshowsatisfactoryresistancetocorrosion.

timeofheating,andthemethodofsubsequentcoolingusedfor

34.2.2Ifmorethanoneofthespecimenstestedinthesame

thissensitizingtreatmenttogetherwiththecorresponding

containerfailtopassthetest,retestallthespecimensin

maximumpermissiblecorrosionrateshallbeasagreedbe-

separatecontainers.

tweenthematerialproducerandpurchaser.

N

OTE

14—Excessivecorrosionofonespecimenmayresultinacceler-

N

ivecorrosion

OTE

11—Themostcommonlyusedsensitizingtreatmentis1hat

675°C(1250°F).

mayoftenbedetectedbychangesinthecolorofthetestsolution,andit

N

maybeappropriatetoprovideseparatecontainersforsuchspecimens

OTE

12—Thesizeandshapeofthespecimenmustbeconsideredwith

respecttoavailablefacilitiesforaccurateweighingandthevolumeoftest

dshouldbemade

ly,themaximumconvenientweightofa

showingwhichspecimensweretestedtogether.

aseofbar,wire,andtubularproducts,the

34.3Afterthespecimenshavebeenplacedintheacidinthe

proportionofthetotalarearepresentedbytheexposedcrosssectionmay

container,passcoolingwaterthroughthecondenser,bringthe

infl-sectionalareasintheseproductsmaybe

portionofendgraininthe

acidtoaboilonthehotplate,andkeepboilingthroughoutthe

specimenshouldthereforebekeptlowunlesssuchsurfaceisactuallyto

testperiod(Note15).Aftereachtestperiod,rinsethespeci-

lattercase,the

menswithwaterandtreatbyscrubbingwithrubberoranylon

proportionofendgraininthespecimenshouldbekepthigh.

brushunderrunningwatertoremoveanyadheringcorrosion

33.2Wherefeasiblefortheproductform,grindallthe

products,maybefacilitated,

specimensurfacesusingCAMI/ANSI120[FEPA/ISOP120]

ifdesired,bydippingthespecimensinacetoneaftertheyare

paper-backed,wetordry,closedcoatedabrasivepaper,with

scrubbed.

sivepaperisuseddry,polishslowly

34.4(Warning—Ithasbeenreportedthatviolentboiling

seabrasiveswithgrindingaids;

portanttoensurethat

somegrindingaidscontainfluoridesthatcanaffectthe

theconcentrationofaciddoesnotincreaseandthatanadequate

measuredcorrosionrate.

numberofboilingchips(whichareresistanttoattackbythe

33.3Removealltracesofoxidescaleandheattintformed

testsolution)arepresent.)

lethatcannotberemovedby

N

OTE

15—Takecaretopreventcontaminationofthetestingsolution,

grinding(forexample,instampednumbers)mayberemoved

especiallybyfluorides,encehas

byusingoneofthepicklingsolutionsdescribedinPractice

shownthatthepresenceofevensmallamountsofhydrofluoricacidwill

A380/A380M,TableA1.1.

tpermissible,for

example,toconductnitric-hydrofluoricacidtestsinthesamehoodwith

33.4Measurethespecimen,includingtheinnersurfacesof

nitricacidtests.

anyholestothenearest0.05mm(0.001in.),andcalculatethe

34.5Thestandardtestconsistsoffiveboilingperiodsof

totalexposedareaincm

2

.

48heachwithafreshtestsolutionbeingusedineachperiod.

33.5Degreasethespecimenusingsuitablenonchlorinated

34.5.1Acombinationofone48-hperiodandtwo96-h

agents,suchassoapandlukewarmwater,oracetone(Note13).

periods(notnecessarilyinthatorder)insteadoffive48-htest

Drythespecimensandweigheachonetothenearest0.001g.

periodsmaybeusedifsoagreedbythepurchaser.

Storethespecimensinadesiccatoruntilthetestistobe

performed.

ationandReport

N

35.1Calculation—Theeffectoftheacidonthematerial

OTE

13—Thecleaningtreatmentdescribedmaybesupplementedby

immersingthespecimeninnitricacid(forexample,20weight%at49to

shallbemeasuredbydeterminingthelossofweightofthe

60°C(120to140°F))for20min,followedbyrinsing,drying,and

specimenaftereachtestperiodandforthetotalofthetest

aseofsmall-diametertubularspecimenswhichcannot

q1,calculatethecorrosionrateforeach

beconvenientlyresurfacedontheinside,itisdesirabletoincludeinthe

specimenforeachtestperiod,andforthetotalofthetest

preparationanimmersioninboilingnitricacid(65%)for2to4husing

poseofthesetreatments

periods.

istoremoveanysurfacecontaminationthatmaynotbeaccomplishedby

35.2Report—Reportthecalculatedcorrosionratesforthe

theregularcleaningmethodandwhichmayincreasetheapparentweight

individualperiodsinchronologicalorder,aswellasthe

10

-

-

-

`

,

,

`

,

`

,

,

`

,

,

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-

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`

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,

,

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,

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`

`

,

,

,

,

,

,

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,

,

`

,

`

`

,

`

`

,

`

,

`

-

-

A262−15

averageforthefiodifiedtestperiods

(

34.5.1)areused,thenidentifyeachresultastothesequence

andlengthofthetestperiod.

ionandBias

36.1Precision—TheprecisionofPracticeCisbeingdeter-

mined.

36.2Bias—Thispracticehasnobiasbecausetheresistance

tointergranularcorrosionisdefinedonlyintermsofthis

practice.

PRACTICEE—COPPER-COPPERSULFATE–16%

SULFURICACIDTESTFORDETECTING

SUSCEPTIBILITYTOINTERGRANULAR

ATTACKINAUSTENITICSTAINLESSSTEELS(

4,5)

37.1Thispracticedescribestheprocedurebywhichthe

copper–coppersulfate–16%sulfuricacidtestisconductedto

determinethesusceptibilityofausteniticstainlesssteelsto

senceorabsenceofintergranular

corrosioninthistestisnotnecessarilyameasureofthe

t

doesnotprovideabasisforpredictingresistancetootherforms

ofcorrosion,suchasgeneralcorrosion,pitting,orstress-

corrosioncracking.

creeningTest

38.1Beforetestinginthecopper–coppersulfate–16%sul-

furicacidtest,specimensofcertaingradesofstainlesssteel

(see

Table4)maybegivenarapidscreeningtestinaccordance

withtheproceduresgiveninPracticeA(Sections4through

13).Preparation,etching,andtheclassificationofetchstruc-

ofetch-structureevalua-

tionsinconnectionwiththecopper–coppersulfate–16%

sulfuricacidtestisspecifiedinTable4.

38.1.1Corrosiontestspecimenshavingacceptableetch

structuresintheOxalicAcidEtchTestwillbeessentiallyfree

ofintergranularattackinthecopper–coppersulfate–16%

ecimensareacceptablewithout

TABLE4UseofEtchStructureClassificationsfromtheOxalic

AcidEtchTestwiththeCopper–CopperSulfate–16%Sulfuric

AcidTest

Grade

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

AISI

A

testinginthecopper–coppersulfate–16%

specimenshavingsuspectetchstructuresmustbetestedinthe

copper–coppersulfate–16%sulfuricacidtest.

38.1.2Heattreatthematerialwhenrequiredbyandin

accordancewith

43.3.1priortoperformingtheetchtest.

yofPractice

39.1Asuitablesampleofanausteniticstainlesssteel,

embeddedincoppershotorgrindings,isexposedtoboiling

acidifixposureinthe

boilingsolution,ranularcrackingor

crazingisevidenceofsusceptibility.

39.2AlternativeTestingProcedures:

39.2.1Unlessprohibitedbythepurchaserinthepurchase

order,thesupplierispermittedtomeettherequirementsof

PracticeEbyperformingatestinaccordancewithISO

3651–2,MethodA,providedthatthetestingperiodshallbea

ensitizationtreatmentisrequired,

sensitizationheattreatmentT1[700°C610°C

(1292°F618°F),30min,waterquench]shallbeusedunless

thesupplierandpurchasershallagreeuponpreparationof

weldedtestpiecestobetestedintheas-weldedcondition.

39.2.2Whenthisalternativetestprocedureisused,itshall

benotedonthetestreport.

tus

40.1ThebasicapparatusisdescribedinSection

18.

40.2SpecimenSupports—Anopenglasscradlecapableof

supportingthespecimensandcoppershotorgrindingsinthe

flaskisrecommended.

N

OTE

16—Itmaybenecessarytoembedlargespecimens,suchasfrom

heavybarstock,incoppershotonthebottomofthetestflr

cradlemayalsobeused.

40.3HeatSource—Anygasorelectricallyheatedhotplate

maybeutilizedforheatingthetestsolutionandkeepingit

boilingthroughoutthetestperiod.

fiedCopperSulfateTestSolution

41.1Dissolve100gofreagentgradecoppersulfate

(CuSO

4

·5H

2

O)in700mLofdistilledwater,add100mLof

sulfuricacid(H

2

SO

4

,cp,spgr1.84),anddiluteto1000mL

withdistilledwater.

N

OTE

17—Thesolutionwillcontainapproximately6weight%of

anhydrousCuSO

4

and16weight%ofH

2

SO

4

.

AcceptableEtch

Structures

Step,

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,

end

end

end

end

end

end

end

end

end

end

end

end

end

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

grain

I

I

I

I

I

I

I

I

I

I

I

I

I

and

and

and

and

and

and

and

and

and

and

and

and

and

II

II

II

II

II

II

II

II

II

II

II

II

II

SuspectEtch

Structures

A

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

Ditch

201

202

301

304

304L

304H

316

316L

316H

317

317L

321

347

Addition

42.1Electrolyticgradecoppershotorgrindingsmaybe

preferredforitseaseofhandlingbeforeandafter

thetest.

42.2Asufficientquantityofcoppershotorgrindingsisto

beusedtocoverallsurfacesofthespecimenwhetheritisina

ventedglasscradleorembeddedinalayerofcoppershoton

thebottomofthetestflask.

42.3Theamountofcopperused,assuminganexcessof

metalliccopperispresent,ectivegalvanic

couplingbetweencopperandthetestspecimenmayhave

importance(

6).

11

Specimenshavingthesestructuresmustbetestedinthecopper–copper

sulfate–16%sulfuricacidtest.

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

A262−15

42.4Thecoppershotorgrindingsmaybereusediftheyare

1hat675°ouldbetakentoavoidcarburizingor

cleanedinwarmtapwateraftereachtest.

ttreatingisbestcarriedoutin

enPreparation

airorneutralsalt.

43.1Thesizeofthesamplesubmittedfortestandthearea

N

OTE

18—Thesensitizingtreatment675°Cisperformedtocheckthe

effectivenessofstabilizedand0.03%maximumcarbonmaterialsin

fromwhichitistobetaken(endormiddleofcoil,midway

resistingcarbideprecipitation,hence,intergranularattack.

surfaceandcenter,andsoforth)isgenerallyspecifiedinthe

ting

nditions

apparatusdictatesthefinalsizeandshapeofthetestspecimen.

44.1Thevolumeofacidifiedcoppersulfatetestsolution

Thespecimenconfigurationshouldpermiteasyentranceand

usedshouldbesufficienttocompletelyimmersethespecimens

removalthroughtheneckofthetestcontainer.

andprovideaminimumof8mL/cm

2

(50mL/in.

2

)ofspecimen

43.1.1

Table5maybeusedasaguidetodetermine

surfacearea.

ayberestrictionsplacedon

44.1.1Asmanyasthreespecimenscanbetestedinthesame

specimensizebythetestingapparatus.

ealtohaveallthespecimensinoneflasktobe

43.1.2Specimensobtainedbyshearingshouldhavethe

ofthesamegrade,

solutionvolume-to-samplearearatioistobemaintained.

shouldbetakenwhengrindingtoavoidoverheatingor

44.1.2Thetestspecimen(s)shouldbeimmersedinambient

“burning.”A“squared”edgeisdesirable.

testsolution,whichisthenbroughttoaboilandmaintained

43.2Anyscaleonthespecimensshouldberemovedme-

imingthetestperiod

chanicallyunlessaparticularsurfacefinishistobeevaluated.

whenthesolutionreachestheboilingpoint.

Chemicalremovalofscaleispermissiblewhenthisisthecase.

N

OTE

19—Measuresshouldbetakentominimizebumpingofthe

Mechanicalremovalofscaleshouldbeaccomplishedwith

120-gritiron-freealuminumoxideabrasive.

amountofcoppershot(eighttotenpieces)onthebottomoftheflaskwill

43.2.1Eachspecimenshouldbedegreasedusingacleaning

convenientlyservethispurpose.

solventsuchasacetone,alcohol,ether,oravapordegreaser

44.1.3Thetimeofthetestshallbeaminimumof15h,

priortobeingtested.

unlessalongertimeisagreeduponbetweenthepurchaserand

43.3Allausteniticmaterialinthe“as-received”(mill-

15h,thetesttimeshallbespecifiedonthe

annealed)conditionshouldbecapableofmeetingthistest.

estsolutionwouldnotbeneededifthetest

43.3.1Specimensofextra-low-carbonandstabilizedgrades

weretorun48oreven72h.(Ifanyadherentcopperremains

aretestedaftersensitizingheattreatmentsat650to675°C

onthespecimen,itmayberemovedbyabriefimmersionin

(1200to1250°F),whichistherangeofmaximumcarbide

concentratednitricacidatroomtemperature.)

tcommonlyusedsensitizingtreatmentis

N

OTE

20—Resultsintheliteratureindicatethatthistestismore

sensitiveifitisrunforlongertimes(3,7).

TABLE5SizesofTestSpecimens

st

TypeofMaterialSizeofTestSpecimen

45.1Thetestspecimenshallbebentthrough180°andover

Wroughtwireorrod:

adiameterequaltothethicknessofthespecimenbeingbent

Upto6mm(¼in.)indiameter,inclFulldiameterby75mm(3in.)(min)

long

(seeFig.10).Innocaseshallthespecimenbebentovera

Over6mm(¼in.)indiameterCylindricalsegment6mm(¼in.)thick

by25mm(1in.)(max)wideby75

to125mm(3to5in.)long

A

Wroughtsheet,strip,plates,orflat

rolledproducts:

Upto5mm(

3

⁄

16

in.)thick,inclFullthicknessby9to25mm("to

1in.)wideby75mm(3in.)(min)

long

Over5mm(

3

⁄

16

in.)thick5to13mm(

3

⁄

16

to½in.)thickby

9to25mm("to1in.)wideby

75mm(3in.)(min)long

B

Tubing:

Upto38mm(1½in.)indiameter,inclFullring,25mm(1in.)wide

C

Over38mm(1½in.)indiameterAcircumferentialsegment75mm

(3in.)(min)longcutfroma25mm

(1-in.)widering

D

A

Whenbendingsuchspecimens,thecurvedsurfaceshallbeontheoutsideofthe

bend.

B

Onesurfaceshallbeanoriginalsurfaceofthematerialundertestanditshallbe

-rolledstriporsheetsmaybetestedinthe

thicknesssupplied.

C

Ringsectionsarenotflattenedorsubjectedtoanymechanicalworkbeforethey

aresubjectedtothetestsolution.

D

Specimensfromweldedtubesover38mm(1½in.)indiametershallbetaken

withtheweldontheaxisofthebend.

FIG.10ABentCopper–CopperSulfate–SulfuricAcid

TestSpecimen

12

-

-

-

`

,

,

`

,

`

,

,

`

,

,

`

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,

,

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,

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`

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,

,

,

,

,

,

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,

,

`

,

`

`

,

`

`

,

`

,

`

-

-

A262−15

smallerradiusorthroughagreateranglethanthatspecifiedin

theproductspecifisofmaterialhavinglow

ductility,suchasseverelycoldworkedmaterial,a180°bend

hallinformthoseconductingthe

PracticeEtestwhenthematerialisinthelowductilityhighly

stressedcondition,suchashighlycoldworkedmaterial.

Determinethemaximumangleofbendwithoutcausingcracks

insuchmaterialbybendinganuntestedspecimenofthesame

confixposureto

theacidifiedcopper–coppersulfatesulfuricacidtestsolution,

themaximumangleofbendwithoutcausingcracksasdeter-

minedfromuntestedlowductilityspecimensshallbeutilized

inevaluationofthespecimensexposedtotheacidified

copper–leof

bendutilizedinevaluatingtestedspecimensshallbereported.

45.1.1Duplicatespecimensshallbeobtainedfromsheet

materialsothatbothsidesoftherolledsamplesmaybebent.

Thiswillassuredetectionofintergranularattackresultingfrom

carburizationofonesurfaceofsheetmaterialduringthefinal

stagesofrolling.

N

OTE

21—Identifytheduplicatespecimeninsuchamannerasto

ensurebothsurfacesofthesheetmaterialbeingtestedaresubjectedtothe

tensionsideofthebends.

45.1.2Samplesmachinedfromroundsectionsorcastma-

terialshallhavethecurvedororiginalsurfaceontheoutsideof

thebend.

45.1.3Thespecimensaregenerallybentbyholdinginavise

nerallycompleted

pecimens

mayrequirebendinginafir

hydraulicpressmayalsobeusedforbendingthespecimens.

45.1.4Tubularproductsshouldbeflattenedinaccordance

withtheflatteningtest,prescribedinTestMethodsand

Definitions

A370.

45.1.5Whenagreeduponbetweenthepurchaserandthe

producer,thefollowingshallapplytoausteniticstainlesssteel

plates4.76mm(0.1875in.)andthicker:

45.1.5.1Samplesshallbepreparedaccordingto

Table5.

45.1.5.2Theradiusofbendshallbetwotimesthesample

thickness,andthebendaxisshallbeperpendiculartothe

directionofrolling.

45.1.5.3Weldsonmaterial4.76mm(0.1875in.)andthicker

shallhavetheabovebendradius,andtheweld-basemetal

interfaceshallbelocatedapproximatelyinthecenterlineofthe

bend.

45.1.5.4Face,root,orsidebendtestsmaybeperformed,

andthetypeofbendtestshallbeagreeduponbetweenthe

dradiusshallnotbeless

thanthatrequiredformechanicaltestingintheappropriate

materialspecification(forbasemetal)orinASMECode

SectionIX(forwelds).

tion

46.1Thebentspecimenshallbeexaminedunderlow(5to

20×)magnification(see

Fig.11).Theappearanceoffissuresor

FIG.11PassingTestSpecimen—ViewoftheBentArea(20×MagnificationBeforeReproduction)

13

A262−15

cracksindicatesthepresenceofintergranularattack(seeFig.

12

).

46.1.1Whenanevaluationisquestionable(seeFig.13),the

presenceorabsenceofintergranularattackshallbedetermined

bythemetallographicexaminationoftheouterradiusofa

longitudinalsectionofthebendspecimenatamagnificationof

100to250×.

46.1.2Crackingthatoriginatesattheedgeofthespecimen

earanceofdeformationlines,

wrinkles,or“orangepeel”onthesurface,withoutaccompa-

nyingcracksorfissures,shallbedisregardedalso.

46.1.3Crackssuspectedasarisingthroughpoorductility

shallbeinvestigatedbybendingasimilarspecimenthatwas

lcomparison

betweenthesespecimensshouldassistininterpretation.

PRACTICEF—COPPER-COPPERSULFATE–50%

SULFURICACIDTESTFORDETERMINING

SUSCEPTIBILITYTOINTERGRANULARATTACK

INAUSTENITICSTAINLESSSTEELS

47.1Thispracticedescribestheprocedureforconducting

theboilingcopper–coppersulfate–50%sulfuricacidtest,

whichmeasuresthesusceptibilityofstainlesssteelstointer-

granularattack.

47.2Thepresenceorabsenceofintergranularattackinthis

testisnotnecessarilyameasureoftheperformanceofthe

tdoesnot

provideabasisforpredictingresistancetoformsofcorrosion

otherthanintergranular,suchasgeneralcorrosion,pitting,or

stress-corrosioncracking.

yofTestMethodF,theCopper–Copper

Sulfate–50%SulfuricAcidTest

48.1Aspecimenrepresentativeofthematerialtobeevalu-

atedisimmersedinaboilingsolutionofcoppersulfateand

sulfuricacidforaspecifiofcopperisalso

immersedinthesolutiontomaintainaconstantcorrosion

ultingmasslossisconvertedtoacorrosion

rate,whichiscomparedtoaspecifiedmaximumvalueto

determinewhetherthematerialhastheresistancetoattack

expectedofthegradeofmaterialbeingtested.

ficanceandUse

49.1Thecopper–coppersulfate–sulfuricacidtestdetects

susceptibilitytointergranularattackassociatedprimarilywith

chromiumcarbideprecipitateinunstabilizedcastaustenitic

stainlesssteelsandincertainwroughtgrades.

49.2Thecopper–coppersulfate–sulfuricacidtestdoesnot

detectsusceptibilitytointergranularattackassociatedprimarily

withsigmaphase.

49.3Thecorrosionpotentialofthecopper–coppersulfate-

–sulfuricacidtesthasbeenreportedas0.1Vascomparedwith

0.6VforPracticeB,0.75to1.0VforPracticeC,and0.1Vfor

PracticeE.(

3)

N

OTE

22—Highercorrosionpotentialindicatesmoreseverelyoxidizing

conditions.

creeningTest

50.1Beforetestinginthecopper–coppersulfate–50%sul-

furicacidtest,specimensofcertaingradesofstainlesssteels

(seeTable6)maybegivenarapidscreeningtestinaccordance

withproceduresgiveninPracticeA,OxalicAcidEtchTestfor

FIG.12FailingTestSpecimen(Notethemanyintergranularfieaat20×MagnificationBeforeReproduction.)

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

14

A262−15

FIG.13NotetheTracesofIntergranularFissuresand“Orange-Peel”eaat20×Magnification

BeforeReproduction.)

TABLE6UseofEtchStructureClassificationsfromtheOxalic

AcidEtchTestWiththeCopper–CopperSulfate–50%Sulfuric

AcidTest

A

Grade

CF-3M

CF-8M

A

tus

51.1ThebasicapparatusisdescribedinSection

18.

51.1.1Substitutionsforthiscondenserorflaskarenot

fically,thecold-fingertypeofcondenserwith

standardErlenmeyerflionrates

obtainedusingthecold-fingertypeofcondenserarelowerthan

thoseobtainedusingtheAllihntypeofcondenserwhetherdue

tolossofvaporortohigheroxygencontentinthesolutionor

both.

tsandMaterials

52.1CupricSulfatePentahydrate(CuSO

4

·5H

2

O);about

64%(CuSO

4

)bymass.

52.1.1Cupricsulfateisaspecificadditivethatestablishes

tutionsarenot

permitted.

52.2SulfuricAcid(H

2

SO

4

),95.0to98.0%bymass.

52.3Apieceofcoppermetalabout3by20by40mm(

1

⁄

8

by

3

⁄

4

by1

1

⁄

2

in.)withabright,cleanfivalentarea

ofcoppershotorchipsmaybeused.

52.3.1Wash,degrease,anddrythecopperbeforeuse.

N

OTE

23—Arinsein5%H

2

SO

4

willcleancorrosionproductsfromthe

copper.

AcceptableEtchStructures

Step,dual,isolatedferrite

Step,dual,isolatedferrite

SuspectEtchStructures

B

Ditch,interdendriticditches

Ditch,interdendriticditches

GradesnotlistedinthistableeitherhavenotbeenevaluatedforuseofPractice

AwithPracticeForhavebeenfoundtogiveacceptableresultsintheetchtest

attercasePracticeAwould

passmaterialthatshouldhavebeensubjectedtothecopper–coppersulfate-

sulfuricacidtest.

B

Specimenshavingthesestructuresshallbetestedinthecopper–copper

sulfate-sulfuricacidtest

ClassificationofEtchStructuresofAusteniticStainlessSteels.

Preparation,etching,andtheclassificationofetchstructures

ofetchstructureevaluationsin

connectionwiththecopper–coppersulfate–50%sulfuricacid

testisspecifiedinTable6.

50.2Heattreatthematerialinaccordancewith55.1priorto

performingtheetchtest.

50.3Ignore“process-affected”areas(see54.1.1);applica-

tionoftheetchtesttotheseareasiscurrentlyoutsidethescope

ofPracticeF.

50.4Corrosiontestspecimenshavingacceptableetchstruc-

turesintheOxalicAcidEtchTestwillbeessentiallyfreeof

intergranularattackinthecopper–coppersulfate–50%sulfuric

ecimensareacceptablewithouttestinginthe

copper–coppersulfate–50%cimens

havingsuspectetchstructuresshallbetestedinthecopper-

–coppersulfate–50%sulfuricacidtest.

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

–CopperSulfate–50%SulfuricAcidTest

Solution

53.1Prepare600mLoftestsolutionasfollows:

53.1.1(Warning—Protecttheeyesandfacebyfaceshield

flaskunderhood.)

15

A262−15

53.1.2First,measure400.0mLofTypeIVreagentwater

andpourintotheErlenmeyerflask.

53.1.3Thenmeasure236.0mLofreagentgradesulfuric

acidslowlytothewaterintheErlenmeyerflask

toavoidboilingbytheheatevolved.(Note7.)

53.1.4Weigh72gofreagentgradecoppersulfate(CuSO

4

·5

H

2

O)andaddtothesulfuricacidsolution.

53.1.5Placethecopperpieceintooneglasscradleandput

itintotheflask.

53.1.6Dropboilingchipsintotheflask.

53.1.7Lubricatetheground-glassjointwithsiliconegrease.

53.1.8Covertheflaskwiththecondenserandcirculate

coolingwater.

53.1.9Heatthesolutionslowlyuntilallofthecoppersulfate

isdissolved.

53.1.10(Warning—Ithasbeenreportedthatviolentboiling

portanttoensurethat

theconcentrationofaciddoesnotincreaseandthatanadequate

numberofboilingchips(whichareresistanttoattackbythe

testsolution)arepresent.)

ng

54.1Obtainandprepareonlybasemetalsamples.

54.1.1Therearetwoclassesofspecimenstobeconsidered:

basemetal,s-affectedmetal

containsanyconditionthataffectsthecorrosionpropertiesof

thematerialinanon-uniformway,suchas(butnotlimitedto)

welds;carburized,nitrided,oroxidizedsurfaces;mechanical

deformation;talhasnone

oftheseconditions.

54.1.2ThePracticeFtestinvolvesimmersingtheentire

specimenandaveragingthemasslossovertheentiresurfaceof

g,carburization,mechanicaldeformation,

andthelike,affectonlypartofaspecimen.

54.1.3Themasslossratefromprocess-affectedmetalis

expectedtodifferfromthatfrombasemetal;thepresenceof

process-affectedmetalinaspecimenwillaffectthecalculated

testresultinanunpredictableway.

54.1.4Ifthepresenceoftheseorotherlocalizedconditions

isaconcerntothepurchaser,thenteststhatdonotaveragethe

masslossoverthetotalspecimensurfacearea,suchasPractice

A,theOxalicAcidEtchTest,orPracticeE,theCopper–Copper

Sulfate–16%SulfuricAcidTestforDetectingSusceptibilityto

IntergranularAttackinAusteniticStainlessSteels,shouldbe

softhetestandacceptancecriteriashallbe

asagreedbythepurchaserandproducer.

54.2Unlessotherwisespecifiedbythepurchaser,thepro-

ceduresforobtainingrepresentativebasemetalsamples,for

removingthespecimensfromthesamples,andthenumberof

specimensshallbeatthediscretionoftheproducer.

ationofTestSpecimens

55.1Heattreatextra-lowcarbonandstabilizedgradesat

650to675°C(1200to1250°F),whichistherangeof

maximumcarbideprecipitation,gthof

timeofheating,andthemethodofsubsequentcoolingusedfor

thissensitizingtreatmenttogetherwiththecorresponding

16

maximumpermissiblecorrosionrateshallbeasagreedbe-

tweenthematerialproducerandpurchaser.

N

OTE

24—Themostcommonlyusedsensitizingtreatmentis1hat

675°C(1250°F).

55.2Preparethespecimens,eachhavingatotalsurfacearea

of5to20cm

2

.

55.3Wherefeasiblefortheproductform,grindallthe

specimensurfacesusingCAMI/ANSI120[FEPA/ISOP120]

paper-backed,wetordry,closedcoatedabrasivepaper,with

sivepaperisuseddry,polishslowly

seabrasiveswithgrindingaids;

somegrindingaidscontainfluoridesthatcanaffectthe

measuredcorrosionrate.

55.4Removealltracesofoxidescaleandheattintformed

lethatcannotberemovedby

grinding(forexample,instampednumbers)mayberemoved

byusingoneofthepicklingsolutionsdescribedinPractice

A380/A380M,TableA1.1.(Residualoxidescalecausesgal-

vanicactionandconsequentactivationinthetestsolution.)

55.5Measurethespecimens,includingtheinnersurfacesof

anyholes,tothenearest0.05mm(0.001in.)andcalculatethe

totalexposedarea.

55.6Degreasethespecimensusingsuitablenonchlorinated

agents,suchassoapandlukewarmwater,

he

specimensinadesiccatoruntilthetestistobeperformed.

ure

56.1Ifthetestsolutionisnotalreadyboiling,bringitto

boiling.

56.1.1Keeptheflaskcoveredwiththecondenser(with

coolingwaterflowing)exceptwheninsertingorremoving

specimens.(See

Note7.)

56.2Turnofftheheatsourceandallowtheboilingto

subside.

56.3Placethespecimeninasecondglasscradle.

56.4Uncovertheflask.

56.5Insertthespecimens.

56.6Replacethecondenserimmediately,restorecooling

waterflow,andturnontheheatsource.

56.7Marktheliquidlevelontheflasktoprovideacheckon

vaporloss,

thereisanappreciablechangeinthelevel,repeatthetestwith

freshsolutionandaregroundspecimen.

56.8Continueimmersionofthespecimenfor120h,then

removethespecimen,rinseinwaterandacetone,

anyadherentcopperremainsonthespecimen,itmaybe

removedbyabriefimmersioninconcentratednitricacidat

roomtemperature.

56.9Weighthespecimenandsubtracttheweightfromthe

originalweight.

A262−15

56.10Intermediateweighingsareusuallynotnecessary;the

r,ifpreliminary

resultsaredesired,thespecimencanberemovedatanytime

forweighing.

56.11Changestothesolutionduringthe120-htestperiod

arenotnecessary.

ationandReport

57.1Theeffectoftheacidsolutiononthematerialis

measuredbydeterminingthelossofweightofthespecimen.

Thecorrosionrateshouldbereportedasmillimetresof

penetrationpermonth(

Note9)calculatedusingEq1.

ds

59.1austeniticstainlesssteel;coppersulfate;corrosion

testing;etchstructures;ferricsulfate;intergranularcorrosion;

nitricacid;oxalicacid

ionandBias

58.1Precision—TheprecisionofPracticeFisbeingdeter-

mined.

58.2Bias—Thispracticehasnobiasbecausetheresistance

tointergranularcorrosionisdefinedonlyintermsofthis

practice.

APPENDIX

NonmandatoryInformation

ATIONOFTHESETESTMETHODS

X1.1General

X1.1.1Thesetestmethodsdetectoneormoreofthree

typesofsusceptibilitytointergranularattack:chromium

carbide,sigmaphase,iceoftestmethod

isaffectedbytheintendedservice,thetypeortypesofattack

expectedfromthatservice,andthegradeofmaterialtobe

evaluated.

X1.1.2Thesepracticesdescribetheproceduresbywhich

thetestsareconductedtodeterminethesusceptibilityof

sence

orabsenceofintergranularcorrosioninthesetestsisnot

necessarilyameasureoftheperformanceofthematerialin

tsdonotprovideabasisfor

predictingresistancetootherformsofcorrosion,suchas

generalcorrosion,pitting,orstress-corrosioncracking.

X1.1.3Susceptibilitytointergranularattackassociatedwith

theprecipitationofchromiumcarbidesisreadilydetectedinall

fivetests.

X1.1.4Sigmaphasemaybepresentinwroughtchromium-

nickel-molybdenumsteels,intitanium-orcolumbium-

stabilizedalloys,andincastmolybdenum-bearingstainless

gmaphasemayormaynotbevisibleinthe

microstructuredependingontheetchingtechniqueandmag-

nifiofthetestmethodscandetectsigma

phase;seethediscussionsbelow.

X1.1.5Inmostcaseseitherthe15-hcopper–coppersul-

fate–16%sulfuricacidtestorthe120-hferricsulfate-sulfuric

acidtest,combinedwiththeOxalicAcidEtchTest,will

stainlessgradeslistedinthisappendixmaybeevaluatedin

thesecombinationsofscreeningandcorrosiontests,except

thosespecimensofmolybdenum-bearinggrades(forexample

316,316L,317,and317L),whichrepresentsteelintendedfor

useinnitricacidenvironments.

X1.1.6The240-hnitricacidtestshouldbeappliedto

stabilizedandmolybdenum-bearinggradesintendedforser-

viceinnitricacidandtoallstainlesssteelgradesthatmightbe

subjecttoendgraincorrosioninnitricacidservice.

X1.1.7Extensivetestresultsonvarioustypesofstainless

steelsevaluatedbythesepracticeshavebeenpublishedin(

8).

17

A262−15

PRACTICEA—OXALICACIDETCHTEST

X1.2TheOxalicAcidEtchTestisusedforacceptanceof

ybeusedin

connectionwithotherevaluationteststoprovidearapid

methodforidentifyingthosespecimensthatarecertaintobe

freeofsusceptibilitytorapidintergranularattackintheseother

tests.

X1.2.1Theetchtestissuitableforuseonlywhenitislisted

intheapplicabletableunderthespecifiedhotacidtest.

X1.2.2Gradesnotlistedintheapplicabletableeitherhave

notbeenevaluatedforuseofPracticeAwiththathotacidtest,

orhavebeenfoundtogiveacceptableresultsintheetchtest

lattercasetheetchtestwouldpassmaterialthatshouldhave

beenrejected.

X1.2.3Whenlisted,theetchtestcanreducethetime

requiredtodeterminewhetherthematerialrepresentedbythe

specimenwillhavealowcorrosionrateinthathotacidtest.

However,whentheetchtestshowsasuspectstructure,the

specifiedhotacidmustbeperformedtoavoidrejectinggood

material.

PRACTICEB—FERRICSULFATE-SULFURICACIDTEST

X1.3PracticeB—Ferricsulfate-sulfuricacidtestisa120-h

testinboilingsolution.

X1.3.1Theferricsulfate-sulfuricacidtestmaybeusedto

mayalsobeusedtochecktheeffectivenessofstabilizing

columbiumortitaniumadditionsandofreductionsincarbon

contentinpreventingsusceptibilitytorapidintergranular

eappliedtowroughtproducts(includingtubes),

castings,andweldmetal.

X1.3.2Theferricsulfate-sulfuricacidtestdetectssuscepti-

bilitytointergranularattackassociatedprimarilywithchro-

miumcarbideprecipitateintheunstabilizedausteniticstainless

steels304,304L,316,316L,317,317L,CF-3,CF-8,CF3M,

CF8M,CG3M,andCG8M;tointergranularattackassociated

withsigmaphasein321,347,CF-3M,CF-8M,CG3M,and

revealssusceptibilityassociatedwithasigma-

likephaseconstituentinstabilizedstainlesssteels321and347,

andincastchromium-nickel-molybdenumstainlesssteels

CF-3M,CF-8M,CG-3M,andCG-8M.

X1.3.3Theferricsulfate-sulfuricacidtestdoesnotdetect

susceptibilitytointergranularattackassociatedprimarilywith

sigmaphaseinwroughtchromium-nickel-molybdenumstain-

lesssteels(316,316L,317,317L),whichisknowntoleadto

doesnotdetectsusceptibilitytoendgrainattack,whichisalso

foundincertainnitricacidenvironments.

N

OTE

X1.1—Todetectsusceptibilitytointergranularattackassociated

withsigmaphaseinausteniticstainlesssteelscontainingmolybdenum,the

nitricacidtest,PracticeC,shouldbeused.

X1.3.4TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestingintheferricsulfate-

sulfuricacidtest;notlistedinTable1

eitherhavenotbeenevaluatedforuseofPracticeAwiththe

ferricsulfate-sulfuricacidtestorhavebeenfoundtogive

acceptableresultsintheetchtestwhilegivingunacceptable

resultsintheferricsulfate–sulfuricacidtest,thuspassing

materialthatshouldberejected.

PRACTICEC—NITRICACIDTEST

X1.4PracticeC—Nitrictestisa240-htestinboiling

solution.

X1.4.1Theboilingnitricacidtestmaybeusedtoevaluate

theheattreatmentaccorded“as-received”so

sometimesusedtochecktheeffectivenessofstabilizing

elementsandofreductionsincarboncontentinpreventing

acticemay

beappliedtowroughtproducts(includingtubes),castings,and

weldmetalofthevariousgradesofstainlesssteel

X1.4.2Intergranularattackinnitricacidisassociatedwith

oneormoreofthefollowing:intergranularprecipitationof

chromiumcarbides,sigmaortransitionphasesin

molybdenum-bearinggrades,andsigmaphaseconstituentsin

lingnitricacidtestshouldnotbeused

18

forextra-low-carbonmolybdenum-bearinggradesunlessthe

materialtestedistobeusedinnitricacidservice.

X1.4.3ThePracticeCtestdetectssusceptibilitytorapid

intergranularattackassociatedwithchromiumcarbideprecipi-

termaybe

formedinmolybdenum-bearingandinstabilizedgradesof

austeniticstainlesssteelsandmayormaynotbevisibleinthe

stalsorevealssusceptibilitytoendgrain

attackinallgradesofstainlesssteels.

X1.4.4Thenitricacidtestdetectssusceptibilitytointer-

granularattackassociatedprimarilywithchromiumcarbide

precipitatein304,304L,316,316L,317,317L,321,347,

CF-3,CF-8,CF-3M,andCF-8M;tointergranularattack

associatedwithsigmaphasein316,316L,317,317L,321,

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

A262−15

347,CF-3M,andCF-8M;andtoend-grainattackin304,304L,

316,316L,317,317L,321,ricacidtestmay

bealsoappliedto309,310,348,410,430,446,andCN-7M.

Thosegradesinwhichsigmaphasemayformmustbetestedin

nitricacidtestwhendestinedforserviceinnitricacid.

X1.4.5TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestinginthenitricacidtest;see

notlistedinTable2eitherhavenotbeen

evaluatedforuseofPracticeAwiththenitricacidtestorhave

beenfoundtogiveacceptableresultsintheetchtestwhile

givingunacceptableresultsinthenitricacidtest,thuspassing

fically,grades316,316L,

317,317L,347,and321cannotbescreenedbecausethese

steelsmaycontainsigmaphasenotvisibleintheetchstructure.

Thismaycauserapidintergranularattackinthenitricacidtest.

PRACTICEE—COPPER–COPPERSULFATE–16%SULFURICACIDTEST

X1.5PracticeE—Copper–CopperSulfate–16%Sulfuric

AcidTestisa15-htestinaboilingsolutionwiththetest

exposureintheboilingsolution,thespecimenisbent.

X1.5.1Thistestmaybeusedtoevaluatetheheattreatment

lsobeusedtoevaluate

theeffectivenessofstabilizingelementadditions(Cb,Ti,and

soforth)andreductionsincarboncontenttoaidinresisting

ughtproductsandweldmaterialof

austeniticstainlesssteelscanbeevaluatedbythistest.

X1.5.2PracticeEindicatessusceptibilitytointergranular

attackassociatedwiththeprecipitationofchromium-rich

carbidesin201,202,301,304,304L,316,316L,317,317L,

321,and347.

X1.5.3Itdoesnotdetectsusceptibilitytointergranular

attackassociatedwithsigmaphaseorend-graincorrosion,both

ofwhichhavebeenobservedonlyincertainnitricacid

environments.

X1.5.4TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestinginthecopper–copper

sulfate–16%sulfuricacidtest;notlistedin

Table4eitherhavenotbeenevaluatedforuseofPracticeA

withthecopper–coppersulfate-16%sulfuricacidtestorhave

beenfoundtogiveacceptabletestsintheetchtestwhilegiving

unacceptableresultsinthecopper–coppersulfate–16%sulfu-

ricacidtest,thuspassingmaterialthatshouldberejected.

PRACTICEF—COPPER–COPPERSULFATE–50%SULFURICACIDTEST

X1.6PracticeF—Copper–CopperSulfate–50%Sulfuric

AcidTestisa120-htestinaboilingsolutionthatcontains

metalliccopper.

X1.6.1Thistestdetectssusceptibilitytointergranularattack

associatedwiththeprecipitationofchromium-richcarbidesin

CF-3M,CF-8M,and316Ti.

X1.6.2Thistestdoesnotdetectsusceptibilitytoattack

associatedwithsigmaphase.

X1.6.3TheOxalicAcidEtchTest(PracticeA)maybeused

toscreencertaingradesfromtestinginthecopper–copper

sulfate–50%sulfuricacidtest;see

notlistedin

Table6eitherhavenotbeenevaluatedforuseofPracticeA

withthecopper–coppersulfate–50%sulfuricacidtestorhave

beenfoundtogiveacceptableresultsintheetchtestwhile

givingunacceptableresultsinthecopper–coppersulfate–50%

sulfuricacidtest,thuspassingmaterialthatshouldberejected.

REFERENCES

(1)Fororiginaldescriptionsoftheuseofetchstructureclassifications,

seeStreicher,M.A.,“ScreeningStainlessSteelsfromthe240-hNitric

AcidTestbyElectrolyticEtchinginOxalicAcid,”ASTMBulletin,No.

188,February1953,p.35;also“ResultsofCooperativeTesting

ProgramfortheEvaluationoftheOxalicAcidEtchTest,”ASTM

Bulletin,No.195,January1954,p.63.

(2)Fororiginaldescriptionsoftheboilingnitricacidtest,seeHuey,W.

R.,“CorrosionTestforResearchandInspectionofAlloys,”

Transactions,AmericanSocietyofSteelTreating,Vol18,1930,p.

1126;also,“ReportofSubcommitteeIVonMethodsofCorrosion

Testing,”Proceedings,ASTM,Vol33,PartI,1933,p.187.

(3)Streicher,M.A.,“TheoryandApplicationofEvaluationTestsfor

DetectingSusceptibilitytoIntergranularAttackinStainlessSteelsand

RelatedAlloys-ProblemsandOpportunities,”IntergranularCorro-

sionofStainlessAlloys,ASTMSTP656,rwalded.,ASTM,

1978,pp.3–84.

(4)Theuseofcoppertoacceleratetheintergranularcorrosionof

sensitizedausteniticstainlesssteelsincoppersulfate–sulfuricacid

wasfinthediscussionofapaperby

Brauns,E.,andPier,G.,StahlundEisen,Vol75,1955,p.579.

(5)Fororiginalevaluationofthecopper–coppersulfate–sulfuricacidtest,

seeScharfstein,L.R.,andEisenbrown,C.M.,“AnEvaluationof

AcceleratedStraussTesting,”ASTMSTP369,ASTM,1963,pp.

235–239.

(6)Subtleeffectsduetovariationsincoppersurfaceareas,galvanic

contact,condenserdesign,etc.,aredescribedbyHerbsleb,G.,and

Schwenk,W.,“UntersuchungenzurEinstellungdesRedoxpotentials

derStrausschenLösungmitZusatzvonMettalischemKupfer,”

-

-

`

,

`

,

`

`

,

`

`

,

`

,

,

`

,

,

,

,

,

,

`

`

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,

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,

,

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`

`

-

`

-

`

,

,

`

,

,

`

,

`

,

,

`

-

-

-

19

A262−15

CorrosionScience,Vol7,1967,pp.501–511.

(7)Walker,W.L.,“VariationsintheEvaluationofASTMA262,Practice

E,Results(ASTMSubcommitteeA01.14RoundRobin),”Intergranu-

larCorrosionofStainlessAlloys,ASTMSTP656,rwald

ed.,ASTM,1978,pp.146–153.

(8)Brown,M.H.,“BehaviorofAusteniticStainlessSteelsinEvaluation

TestsfortheDetectionofSusceptibilitytoIntergranularCorrosion,”

Corrosion,Vol.30,January1974,pp.1–12.

BIBLIOGRAPHY

(1)Fororiginaldescriptionofferricsulfate-sulfuricacidtest,see

Streicher,M.A.,“IntergranularCorrosionResistanceofAustenitic

StainlessSteels:AFerricSulfate-SulfuricAcidTest,”ASTMBulletin,

No.229,April1958,pp.77–86.

(2)Fordetails,seeDeLong,W.B.,“TestingMultipleSpecimensof

StainlessSteelsinaModifiedBoilingNitricAcidTestApparatus,”

SymposiumonEvaluationTestsforStainlessSteels,ASTMSTP93,

ASTM,1950,p.211.

(3)SeeIndustrialandEngineeringChemistry,Vol17,1925,p.756;

also,“ficationsRecommendedby

CommitteeonAnalyticalReagents,”AmericanChemicalSociety,

March1941.

SUMMARYOFCHANGES

CommitteeA01hasidentifiedthelocationofselectedchangestothisstandardsincethelastissue(A262–14)

thatmayimpacttheuseofthisstandard.(ApprovedSept.1,2015.)

(1)Added

Note4to18.1,allowingotherglassjoints.

(2)RevisedApparatusrequirementsin40.1torefertoSection

18.

(3)Addednewsubsection38.1.2toPracticeEtoclarify

requiredheattreatmentthepriortoperformingtheRapid

Screening(Etch)Test.

Committee

A01hasidentifiedthelocationofselectedchangestothisstandardsincethelastissue(A262–13)

thatmayimpacttheuseofthisstandard.(ApprovedJuly1,2014.)

(1)AddednewSection

3onPurityofReagents.

(2)Addedfourreferenceddocuments.

(3)Re-wrotePracticeAintestmethodformat.

(4)Numberedtheun-numberednotesin

Figs.6and7.

(5)Re-wrotePracticeB;Renumberedsubsequentparagraphs,

notes,tables,andreferencestomatch.

(6)Correctedtheconstantin

Eq1.

(7)Re-wrotePracticeC;Renumberedsubsequentparagraphs,

notes,tables,andreferencestomatch.

(8)Removedreferencestothemultiplesampleapparatus.

(9)Re-wrotePracticeFintest-methodformat.

(10)Restrictedspecimentypetobasemetal.

(11)Addedproceduraltext.

(12)Revised45.1.

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