于IzOd-冲击强度的不同测试方法和单位换算

½x½x1/8inch).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.1aK(MJ/m2)aKaKm2MJMJ/m2aKUVaKaKaKaK2K1(J/m)σSK1K1K1K1K1CJ/mK1CIzodImpactTesting(NotchedIzod)ASTMD256andISO1801.Scope:NotchedIzodImpactisasinglepointtestthatmeasuresamaterialsresistancetoimpactfromaswingingpendulum.Izodimpactisdefinedasthekineticenergyneededtoinitiatefractureandcontinuethefractureuntilthespecimenisbroken.Izodspecimensarenotchedtopreventdeformationofthespecimenuponimpact.Thistestcanbeusedasaquickandeasyqualitycontrolchecktodetermineifamaterialmeetsspecificimpactpropertiesortocomparematerialsforgeneraltoughness.2.Testprocedure:Thespecimenisclampedintothependulumimpacttestfixturewiththenotchedsidefacingthestrikingedgeofthependulum.Thependulumisreleasedandallowedtostrikethroughthespecimen.Ifbreakagedoesnotoccur,aheavierhammerisuseduntilfailureoccurs.Sincemanymaterials(especiallythermoplastics)exhibitlowerimpactstrengthatreducedtemperatures,itissometimesappropriatetotestmaterialsattemperaturesthatsimulatetheintendedenduseenvironment.3.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.Thedepthunderthenotchofthespecimenis8mm.5.Data:ASTMimpactenergyisexpressedinJ/morft-lb/in.ImpactstrengthiscalculatedbydividingimpactenergyinJ(orft-lb)bythethicknessofthespecimen.Thetestresultistypicallytheaverageof5specimens.ISOimpactstrengthisexpressedinkJ/m2.ImpactstrengthiscalculatedbydividingimpactenergyinJbytheareaunderthenotch.Thetestresultistypicallytheaverageof10specimens.Thehighertheresultingnumber,thetougherthematerial.J/MKJ/M2ISOASTMASTM10.2MMJ/M10.2KJ/M2