saej406v002

SAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.QUESTIONSREGARDINGTHISDOCUMENT:(724)772-8512FAX:(724)776-0243TOPLACEADOCUMENTORDER;(724)776-4970FAX:(724)776-0790SAEWEBADDRESShttp://www.sae.orgCopyright1998SocietyofAutomotiveEngineers,Inc.Allrightsreserved.PrintedinU.S.A.SURFACEVEHICLE400CommonwealthDrive,Warrendale,PA15096-0001STANDARDAnAmericanNationalStandardJ406REV.MAY1998Issued1942-01Revised1998-05SupersedingJ406FEB95MethodsofDeterminingHardenabilityofSteels1.Scope—ThisSAEStandardprescribestheprocedureformakinghardenabilitytestsandrecordingresultsonshallowandmediumhardeningsteels,butnotdeephardeningsteelsthatwillnormallyairharden.Includedareproceduresusingthe25mm(1in)standardhardenabilityend-quenchspecimenforbothmediumandshallowhardeningsteelsandsubsizemethodforbarslessthan32mm(1-1/4in)indiameter.MethodsfordeterminingcasehardenabilityofcarburizedsteelsaregiveninSAEJ1975.Anyhardenabilitytestmadeunderotherconditionsthanthosegiveninthisdocumentwillnotbedeemedstandardandwillbesubjecttoagreementbetweensupplieranduser.Wheneverchecktestsaremade,alllaboratoriesconcernedmustarrangetousethesamealternateprocedurewithreferencetotestspecimenandmethodofgrindingforhardnesstesting.Forroutinetestingofthehardenabilityofsuccessiveheatsofsteelrequiredtohavehardenabilitywithincertainlimits,itissufficienttodesignatehardenabilitysimplyintermsofdistancefromthequenchedendtothepointatwhichacertainhardnessisobtained.Thisdesignationmayalsobeadequateforcomparingsteelsofdifferentcompositionstoseewhethertheyhavesimilarhardenability.Hardenabilitylimitsforspecifyingsteelinthismannerareobtainedbymeasuringthehardenabilityofasteelwhichhasprovedsatisfactoryfortheuseintended.Thehardenabilitytestmaybeusedinthiswayasanempiricaltest.Fornewcomponentswheremanufacturingexperienceislacking,hardenabilitydatamaybeeffectivelyusedtoestimatethehardnessprofileprovidedbyanygivensteel.Attendantly,theabilitytopredicthardenabilityfromchemicalcompositionhasbecomeincreasinglyimportantwhencomparingvarioussteelgradesordevelopingnewsteelsforspecificapplications.OnesuchprocedureisdescribedinAppendixA.OtherhardenabilitypredictionmethodsareavailablefromtheselectedreferencesinSection2.However,itshouldbeemphasizedthattheuseofanyhardenabilitypredictionproceduredoesnotprecludetheimportanceofconductingJominyend-quenchteststodeterminetheactualhardenabilityofanyspecificgradeofsteel.Hardenabilitydatamaybeusedtoestimatehardnessesobtainablewithanysteelinnewmachinepartsnotyetinproductionandnotsimilartoanypartsonwhichproductionexperienceisavailable.Varioushardenabilityapplicationmethodsaredescribedintheselectedreferences,Section2.1,23to25.Itappearsnoneofthesemethodsareprecise,buttheseareoftenusefulforestimationpurposes.Finalcorrelationonactualpartsisnecessary.SAEJ406RevisedMAY1998-2-2.References2.1ApplicablePublications—Thefollowingpublicationsformapartofthespecificationtotheextentspecifiedherein.UnlessotherwiseindicatedthelastestrevisionofSAEpublicationsshallapply.1.SAEJ417—HardnessTestandHardnessNumberConversion2.SAEEA406—HardenabilityPredictionCalculator3.W.E.JominyandA.L.Boegehold,"AHardenabilityTestforCarburizingSteel,"ASMTransactions,Vol.26(1938,No.2,pp574–599)4.J.L.Burns,T.L.Moore,andR.S.Archer,"QuantitativeHardenability,"ASMTransactions,Vol26(1938),No.1,pp1–335.W.E.Jominy,"AHardenabilityTestforShallowHardeningSteels,"ASMTransactions,Vol.27(1939)pp1072–10856.SymposiumonHardenabilityofAlloySteels,ASM19397.M.AsimowandM.A.Grossmann,"HardeningCharacteristicsofVariousShapes,"AMSTransactions,Vol.28(1940)pp949–9778."StandardizationSoughtinDeterminingtheHardenabilityofSteels"(Asymposium),SAEJournal,Vol.49,No.1(July1941)pp266–2939.A.E.Focke,"HardenabilityofSteel,"IronAge,Aug.20,1942pp37–40:Aug.27,1942,pp.43–51;Sept.3,1942,pp56–5910.MorseHill"TheEnd-QuenchTest:Reproducibility,"ASMTransactions,Vol.31(1943),P923ff.11.SymposiumontheHardenabilityofSteel,SpecialReportNo.36,BritishIronandSteelInstitute,194612.G.K.Manning,"EndQuenchHardenabilityVersusHardnessofQuenchedRounds,"MetalProgress,Vol.50,No.4(October1946)pp674-65013.E.W.Wienman,R.F.Thomson,andA.L.Boegehold,"CorrelationofEndQuenchedTestBarsandRoundsinTermsofHardnessandCoolingCharacteristics,"ASMTransactions,Vol.44(1952)pp802–83414.G.K.Manning,"ComparisonofTestsofHardenabilityofShallowHardeningSteels,"SAEJournal,Vol.61,July1953,pp30–3615.D.J.Carney,"AnotherLookatQuenchants,CoolingRatesandHardenability,"ASMTransactions,Vol.46(1954),pp882–92516.JohnBirtalan,R.G.Henley,Jr.,andA.L.Christenson,"ThermalReproducibilityoftheEnd-QuenchTest,"ASMTransactions,Vol.46(1954),P928ff17.M.A.GrossmanandR.L.Stephenson,"TheEffectofGrainSizeonHardenability,"ASMTransactions,Vol.29(1941),pp1–1918.M.A.Grossmann,"HardenabilityCalculatedfromChemicalCompositions,"AIMETransactions,Vol.150(1942)pp227–25919.I.R.Kramer,S.Siegel,andJ.Brooks,"FactorsfortheCalculationofHardenability,"ASMTransactions,Vol.163(1946),p670ff20.C.F.JatczakandD.J.Girardi,"MultiplyingFactorsfortheCalculationofHardenabilityofHypereutectoidSteelsHardenedfrom1700F,"ASMTransactionsVol.51(1960)p335ff21.E.Just,"NewFormulasforCalculatingHardenabilityCurves,"MetalProgress,November1969,pp87–8822.C.F.Jatczak,"DeterminingHardenabilityfromComposition,"MetalProgress,Vol.100,No.3(September1971),p6023.D.H.Breen,G.H.Walter,C.J.Keith,andJ.T.Sponzilli,"Computer-BasedSystemSelectsOptimumCostSteels,"MetalProgress,I:Dec.1972,p.42;II:Feb.1973,p.76;III:April1973,p.105;IV:June1973,p.83;V:Nov.1973,p.4324.C.S.Siebert,D.V.Doane,andD.H.Breen,"TheHardenabilityofSteels,"AmericanSocietyforMetals,MetalsPark,OH1977,p64ff25.D.V.Doane,J.S.Kirkaldy,"HardenabilityConceptswithApplicationstoSteel,"TheMetallurgicalSocietyofAIME,Warrendale,PA197826.C.T.KunzeandG.Keil,"ANewLookatBoronEffectivenessinHeatTreatedSteels,"SymposiumonBoronSteels,TMS-AIME,Milwaukee,WISept.18,1979SAEJ406RevisedMAY1998-3-27.W.Hewitt,"Hardenability-ItsPredictionformChemicalCompositions,"HeatTreatmentofMetals,Vol.8,1981,pp33–3828.Deb.M.C.ChaturvediandA.K.Jena,"AnalyticalRepresentationofHardenabilityDataforSteels,"MetalsTechnology,1982,Vol9,p7629.J.M.TartagliaandG.T.Eldis,"CoreHardenabilityCalculationsforCarburizingSteels,"Met.Trans.,Vol.15A,No.6,June1984,pp.1173–11832.2RelatedPublications—Thefollowingpublicationsareprovidedforinformationpurposesonlyandarenotarequiredpartofthisdocument.2.2.1ASTM—AvailablefromASTM,100BarrHarborDrive,WestConshohocken,PA19428-2959.ASTMA255—End-quenchTestforHardenabilityofSteel2.2.2OTHERPUBLICATIONSDIN50191—HardenabilityTestingofSteelbyEndQuenchingJISG0561—MethodofHardenabilityTesting(End-QuenchingMethod)3.HardenabilityTestforMediumHardeningSteels3.1Introduction—Thismethodcoverstheprocedurefordeterminingthehardenabilityofsteelbytheend-quenchtestforboththe25mm(1in)standardspecimenandthesubsizetestspecimen.AlsoincludedarechartsforplottinghardenabilitytestresultsandforpredictinghardnessUcurvesinvarioussizesofrounds.Pleasenotethatinthisrevisionthemetricdimensionsareshowntothenearestwholemillimeter.Tolerances,wherenotindicated,areassumedtobe±0.5mmor±1/32in(0.03in).3.2TestSpecimen—Thetestspecimenisa25mm(1in)diametercylinder102mm(4in)longwithmeansforhangingitinaverticalpositionforend-quenching.Figure1showsatestspecimeninthefixturereadyforquenchingillustratingthepreferredformofspecimen.Figure2givesthedetailsofthepreferredtestspecimen.Figure3isanexampleofanoptionalspecimenwhichprovidesthesamediameterandapproximatelythesamelengthandwhichwillprovidesatisfactoryheattransfercharacteristics.Thebarfromwhichthespecimenismachinedshallbeaforgedorrolled29to32mm(1-1/8to1-1/4in)roundrepresentingthefullcrosssectionoftheproduct(orrolled26mm,1-1/16in,roundifoptionaltestspecimen,Figure3,isused).Acastspecimenmaybeusedinlieuofarolledorforgedspecimen,exceptinthecaseofboron-treatedsteel;experiencehasshownthatcastspecimensofboron-treatedsteelsgiveerraticresults.Theoptionofusingas-castspecimensfornon-boronsteels,deletionofnormalizingpriortoheatingforend-quenchingormodificationofothertestingdetailsshallbenegotiatedbetweensupplieranduser.Itisofprimaryimportancethatthespecimenrepresentthefullcrosssectionoftheingot,castbloomorcastbilletsincetestspecimensfromaportionofthebloom,billet,orbarmayintroducefactorstendingtoaffectthereproducibilityoftestresults.Theconditionofthishotformedbarshallbesuchthatthereisnodecarburizationonthe25mm(1in)specimenmachinedfromit.Ifanytestspecimenshowsobviousdefectsorflaws,thespecimenshouldbediscardedandanewspecimenobtained.SAEJ406RevisedMAY1998-4-FIGURE1—HARDENABILITYTESTSPECIMENINFIXTUREFORWATERQUENCHINGFIGURE2—PREFERREDTESTSPECIMENSAEJ406RevisedMAY1998-5-FIGURE3—OPTIONALTESTSPECIMEN3.3OptionalSpecimenPreparation—Thefollowingmethodissatisfactoryformostpurposes,butforchecktestingagainstspecifications,themethodintheprecedingparagraphismandatory.Thetestspecimenshallbemachinedfromthecenterofthebarinthecaseofsectionsfrom32to51mm(1-1/4to2in)roundorsquare.Insectionsover51mm(2in),thetestspecimenshallbemachinedfromone-halfofthesectionwiththeaxisofthespecimenlocatedatapointhalfwaybetweenthecenterandsurfaceofthebarandmarkedtoidentifythepositionofthetestbarwithreferencetotheoriginalbar.Thehardnessreadingsshallbemadeonthetwosidesofthetestspecimencorrespondingtoapositioninthebarapproximatelyhalfwaybetweenthecenterandthesurface.3.4NormalizingPriortoHeatingforEnd-Quenching—Theforgedorrolledroundshallbenormalizedpriortomachiningthetestspecimen.Thisisofimportancesincethestructureofmaterialbeforethefinalaustenitizingtreatmentmaymateriallyaffectthehardeningcharacteristics.Inorderthatvariationsinpriorstructuremaybecontrolledasmuchaspossible,thenormalizingtemperaturelistedinTable1shouldbeused.Thesteelshallbeheldatsuchtemperaturefor1handcooledtoambientinstillair.Ifthenormalizedspecimenistoohard,itmaybegivenashorttimetemperatabout55°C(100°F)belowtheAc1toimprovemachinability.Castspecimensusuallyarenotnormalizedbeforemachining.Therecordofhardenabilitytestresultsmustalwaysstatethepriorthermalhistoryofthespecimentested.SAEJ406RevisedMAY1998-6-3.5HeatingforEnd-Quenching—ThespecimenshallbeheatedtotheaustenitizingtemperatureshowninTable1.Thespecimenshallbeplacedinafurnacewhichisatthespecifiedtemperatureandshallbeheldatthistemperaturefor30to35min.Itisnecessarytodeterminebymeansofathermocouplethetimerequiredforatestspecimentocometotherequiredtemperature.Whileheatingthetestspecimenitisimportanttoinsurethatpracticallynoscalingordecarburizationtakesplaceontheendtobequenched.Thismaybeachievedthroughtheuseofprotectivefurnaceatmospheresorbyplacingthespecimeninacontainerwhichmaintainsanon-oxidizingatmosphere,e.g.,byplacingfinegraphitepowderorcastironchipsinthebaseofthecontainer.Figure4illustratesatypeofcontainerwhichhasbeenusedwithsuccess.However,anysimilartypewillbesatisfactory.FIGURE4—SPECIMENPROTECTINGFIXTURETOBECONSTRUCTEDOFHEAT-RESISTINGALLOYTABLE1—NORMALIZINGANDQUENCHINGTEMPERATURES(1)(2)APPLICABLETOSTEELORDEREDTOEND-QUENCHHARDENABILITYREQUIREMENTS1.Avariationof±5°C(±10°F)fromtheabovetemperatureispermissible.2.WhentestingHsteels,thenormalizingandaustenitizingshouldbethesameasfortheequivalentstandardsteels.EXAMPLES:For8622H,thenormalizingandaustenitizingtemperatureshouldbethesameasforSAE8622;for4032H(carbon0.30/0.37),thetemperatureshouldbethesameasforSAE4032(carbon0.30/0.35).MaximumOrderedCarbonContent,%NormalizingTemperature°CNormalizingTemperature°FAustenitizingTemperature°CAustenitizingTemperature°FSteelSeries1000,1300,1500,4000,4100,4300,4600,4700,5000,5100,6100(3),8100,8600,8700,3.Normalizingandaustenitizingtemperaturesshallbe30°C(50°F)higherforthe6100series.8800,9400Upto0.25incl925170092517000.26to0.36incl900165087016000.37andover387016008451550SteelSeries4800,9300Upto0.25incl92517008451550SteelSeries92000.50andover90016508701600SAEJ406RevisedMAY1998-7-3.6Quenching—Thetestspecimenshallbeplacedonafixturesothatacolumnofwateratatemperatureof5to30°C(40to85°F)maybedirectedagainstthebottomfaceofthespecimen.Thecolumnofwaterpassingthroughanorifice13mm(1/2in)indiametershallrisetoafreeheightof63mm(2-1/2in)abovetheorifice.Thefixtureshallbedryatthebeginningofeachtest.Inperformingthetest,thewatersupplyshallbeshutoffwithaquick-openingvalveandthehotspecimenplacedoverthewaterpipesothatthebottomofthespecimenis13mm(1/2in)fromtheopeningofthewaterpipeandthewatershallthenbeturnedon.Apreferredalternateprocedureistokeepthewaterflowing,butimposeadeflectingplateabovethewaterpipewhiletransferringthetestspecimenfromthefurnacetothefixture,andquicklyremovingtheplatetostarttheend-quench.Thetimebetweenremovalofthespecimenfromthefurnaceandthebeginningofthequenchshallbenotmorethan5s.Thesampleshallremainonthefixtureforatleast10min.Aconditionofstillairshallbemaintainedaroundthespecimenduringcooling.(Ifthequenchedendofthespecimenisnotcoolwhenremovedfromthefixture,investigatewhetherwatertemperatureorwaterflowiswithinspecification.)3.7HardnessMeasurement—Twoflats180degreesapartshallbegroundtoaminimumdepthof0.38mm(0.015in)alongtheentirelengthofthebarandRockwellChardnessmeasurementsmadealongthelengthofthebar.Deviationfromthestandarddepthcanaffectreproducibilityoftestresults,andcorrelationwithcoolingratesinquenchedbars.Thepreparationofthetwoflatsmustbecarriedoutwithconsiderablecare.Theyshouldbemutuallyparallelandthegrindingdoneinsuchamannerthatnochangeofthequenchedstructuretakesplace.Verylightpasses(lessthan0.013mm(0.0005in))withwatercoolingandacoarse,softgrindingwheelarerecommendedtoavoidoverheatingthespecimen.Todetecttemperingduetogrinding,theflatsmaybeetchedasfollows:Twoetchantsolutionsareused:No.1—5%nitricacid(concentrated)and95%waterbyvolume.No.2—50%hydrochloricacid(concentrated)and50%waterbyvolume.Washthesampleinhotwater.EtchinsolutionNo.1untilblack.Washinhotwater.ImmerseinsolutionNo.2for3sandwashinhotwater.Dryinairblast.Thepresenceoflighterordarkerareasindicatesthathardnessandstructurehavebeenalteredingrinding.Allstructuralchangescausedbygrindingshallberemovedbeforehardnesstestsaremade.Thismaybeaccomplishedbyresurfacingandagainetching,ornewflatsmaybeprepared.Whenhardnessindentationsaremade,thetestspecimenmustrestononeofitsflatsonananvilfirmlyattachedtothehardnessmachine.Itisimportantthatnoverticalmovementbeallowedwhenthemajorloadisapplied.Thefixturemustbeconstructedtomovethetestspecimenpastthepenetratorinaccuratestepsof0.5mm(formetricfixture)or1/16in(forU.S.customaryfixture).(RestingspecimenonaV-blockisnotpermitted.)Figure5isanexampleofacommerciallyavailablefixturewhichprovidesforthecontrolledmovementofthespecimen.SAEJ406RevisedMAY1998-8-FIGURE5—COMMERCIALLYAVAILABLEFIXTUREFORPOSITIONINGSPECIMENFORHARDNESSINDENTATIONSTheRockwelltestershouldbecheckedagainststandardtestblocksbeforetestingthehardenabilityspecimen.Itisrecommendedthatthetestblockbeinterposedbetweenthespecimenandtheindentertochecktheseatingoftheindenterandthespecimensimultaneously.Caremustbeexercisedinregisteringthepointoftheindenterwiththehardenedendofthespecimen,aswellasprovidingforaccuratespacingbetweenindentations.Alowpowermeasuringmicroscopeissuitableforuseindeterminingthedistancefromthequenchedendtothecenterofthefirstindentationandincheckingthedistancefromcentertocenterofthesucceedingindentation.Ithasbeenfoundthatwithreasonableoperatingcareandawell-builtfixture,itispracticaltolocatethecenterofthefirstindentation1.5mm±0.075mm(0.0625in±0.003in)fromthequenchedend.Thevariationsbetweenspacingsshouldbeevensmaller.Obviously,itismoreimportanttopositiontheindenteraccuratelywhentestingshallowhardenabilitysteelsthanwhentestingmediumhardenabilitysteels.Thepositioningoftheindentershouldbecheckedwithsufficientfrequencytoprovideassurancethataccuracyrequirementsarebeingmet.Incasesoflackofreproducibilityorofdifferencesbetweenlaboratories,indenterspacingshouldbemeasuredimmediately.3.7.1METRICDISTANCESBETWEENREADINGS—Readingsshallbetakenat1.5,3,5,7,9,11,13,and15mm,thenat5mmintervalsto50mm,oruntil20HRCisreached(iflessthan50mm).SAEJ406RevisedMAY1998-9-3.7.2DISTANCESBETWEENREADINGSINSIXTEENTHSOFANINCH—Readingsshallbetakenatintervalsof1/16inforthefirstinch.Distancesbetweenreadingsbeyond1inmaybeatthediscretionofthetester,butusuallyaretakenatintervalsof1/8inuntil20HRCisreached.(Lessfrequentintervalsmaybeagreeduponbetweensupplieranduser.)Hardnessreadingsshouldbemadeononeflat,orpreferably,twoflats180degreesapart.Whenaflatonwhichreadingshavebeenmadeisusedasabase,theridgesaroundthehardnessindentationsshallberemovedbygrindingunlessafixtureisusedwhichhasbeenrelievedtoaccommodatetheirregularitiesduetotheindentations.Testingontwoflatswillassistinthedetectionoferrorsinspecimenpreparationandhardnessmeasurement.Ifthetwoprobesonoppositesidesdifferbymorethan4HRCpointsatanyoneposition,thetestshouldberepeatedonnewflats,90degreesfromthefirsttwoflats.Iftheretestalsohasgreaterthan4HRCpointsspread,anewspecimenshouldbetested.Forreportingpurposes,hardnessreadingsshouldberecordedtothenearestinteger,with0.5HRCvaluesroundedtothenexthigherinteger.3.8PlottingofTests—Testsshouldbeplottedonastandardchartpreparedforthispurpose(Figure6Aor6B)inwhichtheordinatesrepresenthardnessandtheabscissasrepresentdistancefromthequenchedend.Readingsatidenticaldistancesshouldbeaveragedandtheresultantvaluesusedforplotting.Figures6Aand6BareStandardFormsforPlottingHardenabilityCurves.3.9ConstructionofHardnessUCurves—ChartsareprovidedforusingthehardenabilitycurvetopredicthardnessUcurvesinvarioussizedroundswhenoilorwaterquenched.Figure7showsthesecharts.Thecurvesshowthelocationsinvarioussizesofroundswherethecoolingratesarethesameasatvariouspositionsalongtheend-quenchedhardenabilitytestbar.Itshouldbenotedthatthesecurvesassumegoodheattreatmentpractice—separationofpartsinthequench,goodagitation,andgoodcontroloftemperatureandcleanlinessofthequenchant.Therangesgivenreflectvariationsfoundunderlaboratoryconditions.Underproductionconditions,evenwidervariationsmaybefound.SAEJ406RevisedMAY1998-10-FIGURE6A—STANDARDFORMFORPLOTTINGHARDENABILITYCURVES(MILLIMETERDISTANCES)SAEJ406RevisedMAY1998-11-FIGURE6B—STANDARDFORMFORPLOTTINGHARDENABILITYCURVES(SIXTEENTHSOFANINCHDISTANCES)SAEJ406RevisedMAY1998-12-FIGURE7A—CORRELATIONOFCOOLINGRATESINJOMINYBARANDQUENCHEDROUNDBARSFIGURE7B—CORRELATIONOFCOOLINGRATESINJOMINYBARANDQUENCHEDROUNDBARSSAEJ406RevisedMAY1998-13-FIGURE7C—CORRELATIONOFCOOLINGRATESINJOMINYBARANDQUENCHEDROUNDBARSFIGURE7D—CORRELATIONOFCOOLINGRATESINJOMINYBARANDQUENCHEDROUNDBARSSAEJ406RevisedMAY1998-14-3.10SubsizeTestSpecimen—Fordetermininghardenabilityofsteelreceivedinbarslessthan26mm(1-1/6in)indiameter,thetestbarmaybemade19,13,or6mm(3/4,1/2,or1/4in)indiameter,asdesired,andend-quenchedasprescribedforthe25mm(1in)round.Modificationsinthewaterorificearerequiredforquenchingcylindersoflessthan25mm(1in)diameter.Thedetailsoforificesforquenchingspecimenslessthan25mm(1in)diameteraregiveninTable2.Becauseofthegreaterair-coolingeffectontestspecimenslessthan25mm(1in)diameterandespeciallyinspecimenssmallerthan19mm(3/4in)diameter,thecoolingratesatvariousdistancesfromthequenchedendwillnotbethesameasinthestandardtestspecimen.Hardenabilitycurvesobtainedfromsmallerspecimensarenotcomparablewithcurvesobtainedfromthe25mm(1in)roundspecimen.Ifthestandardhardenabilitycurveisneededfromsubsizespecimens,itbecomesnecessa