ASTM-E8-08-金属材料的抗拉试验方法

Designation:E8/E8M–08AmericanAssociationStateHighwayandTransportationOfficialsStandardAASHTONo.:T68AnAmericanNationalStandardStandardTestMethodsforTensionTestingofMetallicMaterials1ThisstandardisissuedunderthefixeddesignationE8/E8M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.1.Scope*1.1Thesetestmethodscoverthetensiontestingofmetallicmaterialsinanyformatroomtemperature,specifically,themethodsofdeterminationofyieldstrength,yieldpointelon-gation,tensilestrength,elongation,andreductionofarea.1.2Thegagelengthsformostroundspecimensarerequiredtobe4DforE8and5DforE8M.ThegagelengthisthemostsignificantdifferencebetweenE8andE8MTestSpecimensTestspecimensmadefrompowdermetallurgy(P/M)materialsareexemptfromthisrequirementbyindustry-wideagreementtokeepthepressingofthematerialtoaspecificprojectedareaanddensity.1.3Exceptionstotheprovisionsofthesetestmethodsmayneedtobemadeinindividualspecificationsortestmethodsforaparticularmaterial.Forexamples,seeTestMethodsandDefinitionsA370andTestMethodsB557,B557M.1.4Roomtemperatureshallbeconsideredtobe10to38°C[50to100°F]unlessotherwisespecified.1.5ThevaluesstatedinSIunitsaretoberegardedasseparatefrominch/poundunits.Thevaluesstatedineachsystemarenotexactequivalents;thereforeeachsystemmustbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2A356/A356MSpecificationforSteelCastings,Carbon,LowAlloy,andStainlessSteel,Heavy-WalledforSteamTurbinesA370TestMethodsandDefinitionsforMechanicalTestingofSteelProductsB557TestMethodsforTensionTestingWroughtandCastAluminum-andMagnesium-AlloyProductsB557MTestMethodsforTensionTestingWroughtandCastAluminum-andMagnesium-AlloyProducts[Metric]E4PracticesforForceVerificationofTestingMachinesE6TerminologyRelatingtoMethodsofMechanicalTest-ingE29PracticeforUsingSignificantDigitsinTestDatatoDetermineConformancewithSpecificationsE83PracticeforVerificationandClassificationofExten-someterSystemsE345TestMethodsofTensionTestingofMetallicFoilE691PracticeforConductinganInterlaboratoryStudytoDeterminethePrecisionofaTestMethodE1012PracticeforVerificationofTestFrameandSpeci-menAlignmentUnderTensileandCompressiveAxialForceApplicationE1856GuideforEvaluatingComputerizedDataAcquisi-tionSystemsUsedtoAcquireDatafromUniversalTestingMachines3.Terminology3.1Definitions—ThedefinitionsoftermsrelatingtotensiontestingappearinginTerminologyE6shallbeconsideredasapplyingtothetermsusedinthesetestmethodsoftensiontesting.Additionaltermsbeingdefinedareasfollows:3.1.1discontinuousyielding—inauniaxialtest,ahesitationorfluctuationofforceobservedattheonsetofplasticdefor-mation,duetolocalizedyielding.(Thestress-straincurveneednotappeartobediscontinuous.)3.1.2elongationatfracture—theelongationmeasuredjustpriortothesuddendecreaseinforceassociatedwithfracture.Formanymaterialsnotexhibitingasuddendecreaseinforce,theelongationatfracturecanbetakenasthestrainmeasuredjustpriortowhentheforcefallsbelow10%ofthemaximumforceencounteredduringthetest.1ThesetestmethodsareunderthejurisdictionofASTMCommitteeE28onMechanicalTestingandarethedirectresponsibilityofSubcommitteeE28.04onUniaxialTesting.CurrenteditionapprovedFeb.1,2008.PublishedMarch2008.Originallyapprovedin1924.Lastpreviouseditionapproved2004asE8–04.2ForreferencedASTMstandards,visittheASTMwebsite,@astm.org.ForAnnualBookofASTMStandardsvolumeinformation,refertothestandard’sDocumentSummarypageontheASTMwebsite.1*ASummaryofChangessectionappearsattheendofthisstandard.Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959,UnitedStates.3.1.3loweryieldstrength,LYS[FL-2]—inauniaxialtest,theminimumstressrecordedduringdiscontinuousyielding,ignoringtransienteffects.3.1.4uniformelongation,Elu,[%]—theelongationdeter-minedatthemaximumforcesustainedbythetestpiecejustpriortoneckingorfracture,orboth.3.1.4.1Discussion—Uniformelongationincludesbothelas-ticandplasticelongation.3.1.5upperyieldstrength,UYS[FL-2]—inauniaxialtest,thefirststressmaximum(stressatfirstzeroslope)associatedwithdiscontinuousyieldingatorneartheonsetofplasticdeformation.3.1.6yieldpointelongation,YPE—inauniaxialtest,thestrain(expressedinpercent)separatingthestress-straincurve’sfirstpointofzeroslopefromthepointoftransitionfromdiscontinuousyieldingtouniformstrainhardening.Ifthetransitionoccursoverarangeofstrain,theYPEendpointistheintersectionbetween(a)ahorizontallinedrawntangenttothecurveatthelastzeroslopeand(b)alinedrawntangenttothestrainhardeningportionof