uscar-5revision2v002

AvoidanceofHydrogenEmbrittlementofSteelSAE/USCAR-5Revision2March2007ISBN:978-0-7680-1941-4__________________________________________________________________________________________________________________________________________Theresearchdata,analysis,conclusion,opinionsandothercontentsofthisdocumentaresolelytheproductoftheauthors.NeitherSAEInternationalnortheUnitedStatesCouncilforAutomotiveResearch(USCAR)certifiesthecomplianceofanyproductswiththerequirementsofnormakesanyrepresentationsastotheaccuracyofthecontentsofthisdocumentnortoitsapplicabilityforpurpose.Itisthesoleresponsibilityoftheuserofthisdocumenttodeterminewhetherornotitisapplicablefortheirpurposes.Copyright©2007,USCARPrintedinU.S.A.QUESTIONSREGARDINGTHISDOCUMENT:[phone]FAX[phone]TOPLACEADOCUMENTORDER:[phone]FAX[phone]SAE/USCAR-5REVISION2Issued1997-11Revised2007-03AVOIDANCEOFHYDROGENEMBRITTLEMENTOFSTEEL1.SCOPE:Thisstandardoutlinestheconditionsthatenhancetheriskofhydrogenembrittlementofsteelanddefinethereliefproceduresrequiredtominimizetheriskofhydrogenembrittlement.Itisintendedtocontroltheprocess.1.1Hydrogenembrittlementofsteel,whichcancausebrittlefracturesunderstress,occursasaresultoftheabsorptionofhydrogenduringcleaning,phosphatecoatingandplatingprocesses.Thesusceptibilitytohydrogenembrittlementincreaseswithincreasingstress(internalorexternallyappliedstress)andincreasingmaterialstrength.1.2HardnessreadingsinthisspecificationareinVickersscale.SAEJ417shouldbereferredtoforconversiontootherscales.NOTE1:Allreferencestotemperaturesrelatetopartcoretemperatureandnottheindicatedovenairtemperature.Statisticaldataofverificationsintemperatureatthecenteroftheovenloadandoventemperatureshallbeestablishedtodeveloptheovenprofile.Thetemperatureofpartsinabatchtypeofbakingfurnaceshallbemonitoredwithathermocoupleplacedinthemiddleoftheload.Forcontinuousbakeovensatemperaturetracethroughtheovenmustberunwithacalibratedthermocoupleinthelowesttemperatureposition,atleastonceayear.2.REFERENCES:2.1SAEPublications:AvailablefromSAE,400CommonwealthDrive,Warrendale,PA15096-0001.SAEJ417-HardnessTestsandHardnessNumberConversions3.REQUIREMENTS:Thepartsshallbeprocessedinaccordancewiththisspecificationasapplicabletominimizetheriskofhydrogenembrittlement.SpecificapplicationsorcustomerrequirementsmayrequireprocessingthatgoesbeyondtherequirementsofthisspecificationSAE/USCAR-5REVISION2Revised2007-03AVOIDANCEOFHYDROGENEMBRITTLEMENTOFSTEEL-2-3.1Cleaningpriortoheattreatment:Allpartstobeheattreatedtoaspecifiedhardness(coreorsurface)greaterthan353HVmustbecleanedpriortoheattreatmenttoremovephosphateassociatedlubricantresiduesanddetrimentalcontaminantsfromthesurface.NOTE2:Theformationofadeltaferritelayercausedbythepenetrationofphosphorusduringthehardeningprocessenhancesthepossibilityofembrittlement.3.1.1AcidCleaningafterheattreatmentorcoldworking:Acidcleaningofpartstobeheattreatedtoaspecifiedhardness(coreorsurface)greaterthan353HVorhighlystressedcoldworkedpartsenhancessusceptibilitytohydrogenembrittlement,andshallbeminimized.Ifhighhardnesspartsaretobeacidcleaned,itisrequiredthataprocedurebeestablishedforprocessingthepartsthatlimitsthetimeintheacidbathtoamaximumof10minutes.Partswhichareacidcleanedandsubsequentlyoiled,phosphated,mechanically(non-electrolytically)plated,orelectroplatedshallfollowtherequirementsof3.2,3.3,3.4,or3.5,asapplicable.Allotherpartswhichareacidcleanedshallnotbeusedfor48hoursoralternatelythesepartsshallbebakedfor1hourminimumat110°Cminimumfollowingcleaning.3.2Oiled:Allpartstobeheattreatedtoaspecifiedhardness(coreorsurface)greaterthan353HVwhichareacidcleanedbeforeapplicationofoilshallnotbeusedfor48hoursoralternativelythesepartsshallbebakedfor1hourminimumat110°Cminimumafteracidcleaningpriortooilapplication.3.3Phosphated:Allpartstobeheattreatedtoaspecifiedhardness(coreorsurface)greaterthan353HV,whichareacidcleanedand/orphosphatecoatedshallnotbeusedfor48hoursoralternativelythesepartsshallbebakedfor1hourminimumat110°Cminimumfollowingphosphatecoating.3.4MechanicalPlated:Allpartstobeheattreatedtoaspecifiedhardness(coreorsurface)greaterthan353HVwhichareacidcleanedbeforemechanicalplatingshallnotbeusedfor48hoursoralternativelythesepartsshallbebakedfor1hourminimumat110°Cminimumfollowingmechanicalplating.3.5Electroplated:3.5.1Allpartseitherhardenedorcoldworkedtoaspecifiedhardness(coreorsurface)greaterthan353HV,whenelectroplatedshallbebaked.Withinonehouraftertheelectroplatingprocessandbeforeanysupplementarychemicaltreatment,partsshallbeplacedinanovenandheatingcommenced.Thepartsshallbeheatedtoaparttemperatureof200°Cminimumandheldatthistemperatureforaminimumoffourhours.Thistemperaturerangeshallbereachedwithinonehouraftercommencementofheating.3.5.2Allpartstobeheattreatedtoaspecifiedhardness(coreorsurface)greaterthan390HV,whenelectroplatedshallbebaked.Withinonehouraftertheelectroplatingprocessandbeforeanysupplementarychemicaltreatment,partsshallbeplacedinanovenandheatingcommenced.Thepartsshallbeheatedtoaparttemperatureof200°Cminimumandheldatthistemperatureforaminimumo