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关于IzOd冲击强度的不同测试方法和单位换算IzodImpactTesting(NotchedIzod)ASTMD256andISO1801.Scope:NotchedIzodImpactisasinglepointtestthatmeasuresamaterialsresistancetoimpactfromaswingingpendulum.Izodimpactisdefinedasthekineticenergyneededtoinitiatefractureandcontinuethefractureuntilthespecimenisbroken.Izodspecimensarenotchedtopreventdeformationofthespecimenuponimpact.Thistestcanbeusedasaquickandeasyqualitycontrolchecktodetermineifamaterialmeetsspecificimpactpropertiesortocomparematerialsforgeneraltoughness.2.Testprocedure:Thespecimenisclampedintothependulumimpacttestfixturewiththenotchedsidefacingthestrikingedgeofthependulum.Thependulumisreleasedandallowedtostrikethroughthespecimen.Ifbreakagedoesnotoccur,aheavierhammerisuseduntilfailureoccurs.Sincemanymaterials(especiallythermoplastics)exhibitlowerimpactstrengthatreducedtemperatures,itissometimesappropriatetotestmaterialsattemperaturesthatsimulatetheintendedenduseenvironment3.ReducedTemperatureTestprocedure:Thespecimensareconditionedatthespecifiedtemperatureinafreezeruntiltheyreachequilibrium.Thespecimensarequicklyremoved,oneatatime,fromthefreezerandimpacted.NeitherASTMnorISOspecifyaconditioningtimeorelapsedtimefromfreezertoimpact-typicalvaluesfromotherspecificationsare6hoursofconditioningand5secondsfromfreezertoimpact.4.Specimensize:ThestandardspecimenforASTMis64x12.7x3.2mm(2½x½x1/8inch).Themostcommonspecimenthicknessis3.2mm(0.125inch),butthepreferredthicknessis6.4mm(0.25inch)becauseitisnotaslikelytobendorcrush.Thedepthunderthenotchofthespecimenis10.2mm(0.4inches).ThestandardspecimenforISOisaType1Amultipurposespecimenwiththeendtabscutoff.Theresultingtestsamplemeasures80x10x4mm.Thedepthunderthenotchofthespecimenis8mm5.Data:ASTMimpactenergyisexpressedinJ/morft-lb/in.ImpactstrengthiscalculatedbydividingimpactenergyinJ(orft-lb)bythethicknessofthespecimen.Thetestresultistypicallytheaverageof5specimens.ISOimpactstrengthisexpressedinkJ/m2.ImpactstrengthiscalculatedbydividingimpactenergyinJbytheareaunderthenotch.Thetestresultistypicallytheaverageof10specimens.Thehighertheresultingnumber,thetougherthematerial.看完之后，以前的J/M和KJ/M2的单位换算总算清楚了，如果不考虑别的因素，单从厚度上考虑，ISO是除以截面积，而ASTM是除以厚度，ASTM除掉缺口后的宽度是10.2MM，那两者单位的换算就是J/M除以10.2后就是KJ/M2，当然这个不考虑样条不同的影响。