ASTM C692-2006 评定奥氏体不锈钢热绝缘材料对外部应力腐蚀开裂趋势影响的标准试验方法

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【英文标准名称】:StandardTestMethodforEvaluatingtheInfluenceofThermalInsulationsonExternalStressCorrosionCrackingTendencyofAusteniticStainlessSteel
【原文标准名称】:评定奥氏体不锈钢热绝缘材料对外部应力腐蚀开裂趋势影响的标准试验方法
【标准号】:ASTMC692-2006
【标准状态】:现行
【国别】:
【发布日期】:2006
【实施或试行日期】:
【发布单位】:美国材料与试验协会(ASTM)
【起草单位】:C16.31
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:奥氏体钢;建筑;腐蚀;裂开;不锈的;钢;试验;隔热
【英文主题词】:austeniticstainlesssteel;chloride;Danatest;Driptest;externalstresscorrosioncracking(ESCC);qualificationtest;thermalinsulation;wickinginsulation;
【摘要】:Aninherentcharacteristicofsomealloysofausteniticstainlesssteelistheirtendencytocrackatstresspointswhenexposedtocertaincorrosiveenvironments.ThemechanismsofESCCarecomplexandnotcompletelyunderstoodbutareapparentlyrelatedtocertainmetallurgicalproperties.Chlorideionsconcentratedatastresspointwillcatalyzecrackformation.IthasbeenreportedthatotherhalideionsdonotpromoteESCCtothesamedegreeasdoeschlorideusingthetesttechnologyofTestMethodC692(driptest).3Chloridesarecommontomanyenvironments,sogreatcareshallbetakentoprotectausteniticstainlesssteelfromchloridecontamination.Mostthermalinsulationswillnot,ofthemselves,causestresscorrosioncrackingasshownbyqualificationtests.Whenexposedtoelevated-temperature(boilingpointrange),environmentscontainingchlorides,moisture,andoxygen,however,someinsulationsystemsactascollectingmedia,transmigratingandconcentratingchloridesonheatedstainlesssteelsurfaces.Ifmoistureisnotpresent,thechloridesaltscannotmigrate,andstresscorrosioncrackingbecauseofchloride-contaminatedinsulationcannottakeplace.Insulationmaterialsareavailablethatarespeciallyformulatedtoinhibitstresscorrosioncrackinginthepresenceofchloridesthroughmodificationsinbasiccompositionorincorporationofcertainchemicaladditives.Theabilityofthe28-daytesttomeasurethecorrosionpotentialofinsulationmaterialsisdocumentedbyKarnes,4whosedataappeartohavebeenusedforconstructionoftheacceptabilitycurveusedinSpecificationC795andotherspecifications.Themetalforallofthecouponsusedinthistestmethod(C692)shallbequalified(seeSection13)toascertainthatunderconditionsofthetest,chlorideionswillcausethemetaltocrack,anddeionizedwateralonewillnotcausecracks.1.1Thistestmethodcoverstwoproceduresforthelaboratoryevaluationofthermalinsulationmaterialstodeterminewhethertheycontributetoexternalstresscorrosioncracking(ESCC)ofausteniticstainlesssteelduetosolublechlorideswithintheinsulation.ThislaboratoryprocedureisnotintendedtocoverallofthepossiblefieldconditionsthatcontributetoESCC.1.2Whilethe1977editionofthistestmethod(Danatest)isapplicableonlytowicking-typeinsulations,theproceduresinthiseditionareintendedtobeapplicabletoallinsulatingmaterials,includingcements,someofwhichdisintegratewhentestedinaccordancewiththe1977edition.Wickinginsulationsarematerialsthatwetthroughandthroughwhenpartially(50to75%)immersedinwaterforashortperiodoftime(10minorless).1.3Theseproceduresareintendedprimarilyasapreproductiontestforqualificationofthebasicchemicalcompositionofaparticularmanufacturer'sproductandarenotintendedtoberoutinetestsforongoingqualityassuranceorproductionlotcompliance.TestMethodsC871,ontheotherhand,isusedforconfirmationofacceptablechemicalpropertiesofsubsequentlotsofinsulationpreviouslyfoundacceptablebythistestmethod.1.4Thevaluesstatedininch-poundunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:Q25
【国际标准分类号】:77_060;77_060
【页数】:7P.;A4
【正文语种】: