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【英文标准名称】:StandardPracticeforHeatAgingofPlasticsWithoutLoad
【原文标准名称】:通用的玻璃制品齿轮油氧化和热稳定特性的标准实施规程
【标准号】:ASTMD3045-1992(2010)
【标准状态】:现行
【国别】:美国
【发布日期】:1992
【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】:D20.50
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:aging;exposure;heat;heat-aging;thermal-aging;Acceleratedaging/testing--plastics;Heataging;Heatingtests--plastics;Oxidationtesting--plastics;Thermalanalysis(TA)--plastics
【摘要】:Theuseofthispracticepresupposesthatthefailurecriteriaselectedtoevaluatematerials(thatis,thepropertyorpropertiesbeingmeasuredasafunctionofexposuretime)andthedurationoftheexposurecanbeshowntorelatetotheintendeduseofthematerials.Plasticmaterialsexposedtoheatmaybesubjecttomanytypesofphysicalandchemicalchanges.Theseverityoftheexposuresinbothtimeandtemperaturedeterminestheextentandtypeofchangethattakesplace.Aplasticmaterialisnotnecessarilydegradedbyexposuretoelevatedtemperatures,butmaybeunchangedorimproved.However,extendedperiodsofexposureofplasticstoelevatedtemperatureswillgenerallycausesomedegradation,withprogressivechangeinphysicalproperties.Generally,shortexposuresatelevatedtemperaturesmaydriveoutvolatilessuchasmoisture,solvents,orplasticizers,relievemoldingstresses,advancethecureofthermosets,andmaycausesomechangeincoloroftheplasticorcoloringagent,orboth.Normally,additionalshrinkageshouldbeexpectedwithlossofvolatilesoradvanceinpolymerization.Someplasticmaterialsmaybecomebrittleduetolossofplasticizersafterexposureatelevatedtemperatures.Othertypesofplasticsmaybecomesoftandsticky,eitherduetosorptionofvolatilizedplasticizerorduetobreakdownofthepolymer.Thedegreeofchangeobservedwilldependonthepropertymeasured.Differentproperties,mechanicalorelectrical,maynotchangeatthesamerate.Forinstance,thearcresistanceofthermosettingcompoundsimprovesuptothecarbonizationpointofthematerial.Mechanicalproperties,suchasflexuralproperties,aresensitivetoheatdegradationandmaychangeatamorerapidrate.Ultimatepropertiessuchasstrengthorelongationaremoresensitivetodegradationthanbulkpropertiessuchasmodulus,inmostcases.Effectsofexposuremaybequitevariable,especiallywhenspecimensareexposedforlongintervalsoftime.Factorsthataffectthereproducibilityofdataarethedegreeoftemperaturecontroloftheenclosure,humidityoftheoven,airvelocityoverthespecimen,andperiodofexposure.Errorsinexposurearecumulativewithtime.Certainmaterialsaresusceptibletodegradationduetotheinfluenceofhumidityinlong-termheatresistancetests.Materialssusceptibletohydrolysismayundergodegradationwhensubjectedtolong-termheatresistancetests.Itisnottobeinferredthatcomparativematerialrankingisundesirableorunworkable.Onthecontrary,thispracticeisdesignedtoprovidedatawhichcanbeusedforsuchcomparativepurposes.However,thedataobtainedfromthispractice,sinceitdoesnotaccountfortheinfluenceofstressorenvironmentthatisinvolvedinmostreallifeapplications,mustbeusedcautiouslybythedesigner,whomustinevitablymakematerialchoicesusingadditionaldatasuchascreepandcreeprupturethatareconsistentwiththerequirementsofhisspecificapplication.Itispossibleformanytemperatureindexestoexist,infact,oneforeachfailurecriterion.Therefore,foranyapplicationofthetemperatureindextobevalid,thethermalagingprogrammustduplicatetheintendedexposureconditionsoftheendproduct.Ifthematerialisstressedintheendproductinamannernotevaluatedintheagingprogram,thetemperatureindexthusderivedisnotapplicabletotheuseofthematerialinthatproduct.TherecanbeverylargeerrorswhenArrheniusplotsorequationsbasedondatafromexperimentsataseriesoftemperaturesareusedtoestimatetimetoproduceadefinedpropertychangeatsomelowertemperature.Thisestimateoftimetoproducethepropertychangeorx201C;failurex201D;atthelowertemperatureisoftencalledthex201C;【英文标准名称】:Methodsoftestingdoors;behaviourofdoorleavesplacedbetweentwodifferentclimates;germanversionEN79:1985
【原文标准名称】:门的检验方法.在两种不同气候条件下门扇的形状
【标准号】:DINEN79-1990
【标准状态】:作废
【国别】:德国
【发布日期】:1990-11
【实施或试行日期】:
【发布单位】:德国标准化学会(DIN)
【起草单位】:
【标准类型】:()
【标准水平】:()
【中文主题词】:门;湿度效应;元部件;建筑系统构件;试验;潮气;气候荷载;气候;建筑;门扉
【英文主题词】:construction;doors;components;constructionsystemsparts;moisture;doorleaves;climate;testing;climaticloading;humidityeffects
【摘要】:
【中国标准分类号】:P32
【国际标准分类号】:7486
【页数】:4P;A4
【正文语种】:德语