【英文标准名称】:StandardPracticeforLaboratoryScreeningofMetallicContainmentMaterialsforUseWithLiquidsinSolarHeatingandCoolingSystems
【原文标准名称】:太阳能加热和制冷系统中贮存液体用金属容器材料的实验室遮蔽的标准实施规程
【标准号】:ASTME712-1980(2009)
【标准状态】:现行
【国别】:美国
【发布日期】:1980
【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】:E44.05
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:
【英文主题词】:corrosion;deterioration;highpressure;immersion;metalliccontainmentmaterials;solarcollector;solarheatingandcooling;Containmentsystems/applications;Corrosion--metals/alloys;Corrosion--solardevices;Crevicecorrosion;Deterioration;D
【摘要】:Atthistime,noneofthesetestshasbeendemonstratedtocorrelatewithfieldservice.Itisessentialthatconsiderationbegiventotheappropriatepairingofmetalandfluidsincetheseproceduresdonotrestricttheselectionofeitherthecontainmentmaterialorthefluidfortesting.Likewise,knowledgeofthecorrosionprotectionmechanismandtheprobablemodeoffailureofaparticularmetalishelpfulintheselectionoftestconditionsandtheobservation,interpretation,andreportingoftestresults.Thedesignofsolarheatingandcoolingsystemsstronglyaffectstheapplicabilityoftheresultsofthelaboratoryscreeningtests.Therefore,theresultsoftheselaboratoryproceduresshouldbeconfirmedbycomponentandsystemstestingunderactualorsimulatedserviceconditions.Table1isprovidedtoassistinanorderlyconsiderationoftheimportantfactorsintesting.Itisexpectedthattheuserofthetestprocedurewillinvestigatearangeoftesttimesandtemperaturesforthecontainmentmaterialinametal/fluidpair,andadjustthetimeandtemperatureoftestingasnecessary.Note18212;Corrosion,whethergeneralorlocalized,isatime-dependentphenomenon.Thistimedependencecanshowsubstantialnonlinearity.Forexample,formationofaprotectiveoxidewilldiminishcorrosionwithtime,whilecertainformsoflocalizedattackacceleratewithtime.Theminimumtimerequiredforatesttoprovideacorrosionratethatcanbeextrapolatedforthepredictionoflong-termperformancevarieswidely,dependingontheselectionofmetalandfluid,andontheformofcorrosionattack.Therefore,itisnotpossibletoestablishasingleminimumlengthoftestapplicabletoallmaterialsandconditions.However,itisrecommendedthatforthetestsdescribedinthispractice,atestperiodofnolessthan30daysbeused.Furthermore,itisrecommendedthattheeffectoftimeoftestingbeevaluatedtodetectanysignificanttimedependenceofcorrosionattack.Itisessentialforthemeaningfulapplicationoftheseproceduresthatthelengthofthetestbeadequatetodetectchangesinthenatureofthefluidthatmightsignificantlyalterthecorrosivityofthefluid.Forexample,exhaustionofchemicalinhibitororchemicalbreakdownofthefluidmayoccurafterperiodsofmonthsinselectedcyclesofoperation.Note28212;Manyfluidsthatmaybeconsideredforsolarapplicationscontainadditivestominimizethecorrosivityofthefluid.Manysuchadditivesareusefulonlywithinaspecificconcentrationrange,andsomeadditivesmayactuallyacceleratecorrosioniftheconcentrationfallsbelowacriticallevel.Depletionkineticscanbeastrongfunctionoftheexposedmetalsurfacearea.Therefore,fortestsinvolvingfluidswithsuchadditives,considerationmustbegiventotheratioofmetalsurfaceareatofluidvolumeasitmayrelatetoanoperatingsystem.TABLE1SignificantVariablesinEvaluationofContainmentMaterial/HeatTransferFluidPairsATestAspectVariableTemperatureFlowRateI.
OperatingConditionsofSystem:
A.Operating,fullflo........
【中国标准分类号】:A82
【国际标准分类号】:77_040_99
【页数】:8P.;A4
【正文语种】:英语