ASTM D4508-2010 塑料破碎碎片冲击强度的标准试验方法

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【英文标准名称】:StandardTestMethodforChipImpactStrengthofPlastics
【原文标准名称】:塑料破碎碎片冲击强度的标准试验方法
【标准号】:ASTMD4508-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D20.10
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:breakingenergy;cantileverimpact;chipimpactstrength;impactplastics;impacttesting;microcracks;pendulum;plastics;smallspecimenimpact;weatheredimpactstrength;Chipimpactstrength;Environmentalcontrol/fate;Cantilevertesting;E
【摘要】:Thechip-impacttestisavariationoftheIzodimpacttestdescribedinTestMethodsD256.Thespecimengeometryhasbeenchosentofitthreebasiccriteriaasfollows:Thespecimenisrelativelythinandisstruckonthebroadsurfacesothatthetestresultissensitivetotheconditionofthesurface,Thespecimenisrelativelysmallforefficientutilizationofspaceinacceleratedtestingmediaordevicesandtominimizeamountsofmaterialneededfortesting,andThespecimencanbetestedusingastandardIzodpendulumtester.Ithasbeenfoundthata12.7-mm(0.500-in.)widestripwithathicknessintherangefrom1.02to3.18mm(0.040to0.125in.)meetstheabovecriteria.Muchexperimentalworkon1.78-mm(0.070-in.)stripshasdemonstratedtheutilityofthechip-impacttesttotrackweatheragingofavarietyofmaterials.Thedistance(L)betweenclampingandimpactpoints(strikerheight)willaffecttestresults.ExtensiveexperimentalworkhasestablishedthataratioofL=2.182h(whereListhedistancebetweenclampingandimpactpointsandhisthethicknessofthespecimen)willprovideaccurateandsensitivechip-impactvalues.Increasingthisratio(thatis,raisingthestrikerheightforagiventhickness)lowerschip-impactvaluesandreducessensitivityofthetest.Decreasingtheaboveratio(thatis,loweringthestrikerheightforagiventhickness)resultsinashearingofthespecimenratherthanthedesiredbendingandbreaking.Ingeneral,thechip-impactvalueduringweatheringvariesaccordingtospecimenthickness,evenafteradjustingstrikerheightsforconstantdeflection,asgiveninTable1.Reportthethicknessofthespecimen,alongwiththetestvalues,makingcomparisonsonlybetweensampleswithsimilarthickness.ThestandardIzodMethodsA,C,D,andErequirethatthetypeoffailureforeachspecimenberecordedasoneofthefourcodedcategoriesdefinedasfollows:1.1Thepurposeofthistestmethodistoprovideanimpacttestthatcanbeperformedonsmallspecimensofplasticsofdifferentthicknesses.Thistestmethodisespeciallysuitedforobservingtheeffectsofmicrocrackscausedbyweathering,orbyexposuretosolventsorotherhostileenvironments,onthesurfaceofplasticmaterials.Itisnotmeanttobeusedasareplacementforanyexistingimpacttest,butcanbeusedtomeasureimpactoncouponsmachinedfromfinishedpartsthatcannotbetestedbythedrop-weight,Izod,orCharpymethodbecauseofshapeorthicknesslimitations.1.2Thechip-impacttestisrunonsmall,flat,unnotchedspecimensusingastandardpendulum-impactdevice.Thetestplacestheimpactedsurfaceintensionand,fornotch-sensitivematerials,isextremelysensitivetothepresenceofsurfacemicrocracks.Thus,forplasticsthatdevelopsurfacecrackswhenexposedoutdoors,thechip-impacttestisaseveretestoftheweatheredimpactstrength.1.3Round-robintestinghasindicatedthatmaterialsthatbreakattotalenergyvaluesoflessthan0.17joules(1.5in.-lbf)havewithin-laboratorycoefficientsofvariationofapproximately30%.Therefore,suchvaluesareconsideredoutofthenormaltestingrangeforthistest.1.4ThevaluesstatedinSIunitsaretoberegardedasstandard.Thevaluesgiveninparenthesesareforinformationonly.1.5ThereisnoknownISOequivalenttothistestmethod.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuser......
【中国标准分类号】:G31
【国际标准分类号】:83_080_01
【页数】:6P.;A4
【正文语种】:英语