__________________________________________________________________________________________________________________________________________SAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.Copyright©2010SAEInternationalAllrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystemortransmitted,inanyformorbyanymeans,electronic,mechanical,photocopying,recording,orotherwise,withoutthepriorwrittenpermissionofSAE.TOPLACEADOCUMENTORDER:Tel:877-606-7323(insideUSAandCanada)Tel:+1724-776-4970(outsideUSA)Fax:724-776-0790Email:CustomerService@sae.orgSAEWEBADDRESS:://(CompositionsimilartoUNSR56401)RATIONALEAMS4991Dhasbeenrevisedtochangethegoverningheattreatprocesscontrolspecification,addnewprovisionsforcertificationandserialization,introducepurchaserallowancetouseASTME1320radiographicstandards,andresultsfromaFiveYearReviewandupdateofthisspecification1.SCOPE1.1FormThisspecificationcoversatitaniumalloyintheformsofinvestmentcastingshavingfourgradesofpermissiblediscontinuities.1.2ApplicationThesecastingshavebeenusedtypicallyforpartsofintricatedesignrequiringacombinationofgoodstrength-to-weightratio,creepandfatigueproperties,andcorrosionresistanceupto750°F(399°C),butusageisnotlimitedtosuchapplications.1.3ClassificationQualitygradesA,B,C,andDaredefinedin3.7.Ifaspecificgradeisnotspecified(See8.2.1),GradeCorbettershallbesupplied.2.APPLICABLEDOCUMENTSTheissueofthefollowingdocumentsineffectonthedateofthepurchaseorderformsapartofthisspecificationtotheextentspecifiedherein.Thesuppliermayworktoasubsequentrevisionofadocumentunlessaspecificdocumentissueisspecified.Whenthereferenceddocumenthasbeencancelledandnosupersedingdocumenthasbeenspecified,thelastpublishedissueofthatdocumentshallapply.--`,`,,```````,,,`,`,,,`,,``-`-`,,`,,`,`,,`---SAEAMS4991DPage2of182.1SAEPublicationsAvailablefromSAEInternational,400CommonwealthDrive,Warrendale,PA15096-0001,Tel:877-606-7323(insideUSAandCanada)or724-776-4970(outsideUSA),:610-832-9585,(See8.2.2and8.2.3).TABLE1-COMPOSITIONElementminmaxAluminum5.506.75Vanadium3.504.50Iron--0.30Oxygen--0.20Carbon--0.10Nitrogen--0.05(500ppm)Hydrogen(3.1.2)--0.015(150ppm)Yttrium(3.1.1)--0.005(50ppm)OtherElements,each(3.1.1)--0.10OtherElements,total(3.1.1)--0.40Titaniumremainder--`,`,,```````,,,`,`,,,`,,``-`-`,,`,,`,`,,`---SAEAMS4991DPage3of183.1.1Determinationnotrequiredforroutineacceptance.3.1.2ForHydrogenAnalysisConductedinAccordancewithASTME1447Samplesizemaybeaslargeas0.35gram.3.1.3CheckAnalysisCompositionvariationsshallmeettheapplicablerequirementsofAMS2249.3.2MeltingPractice3.2.1Castingsandspecimensshallbepouredatthecastingvendor’sfacilityeitherfromaremelt(See8.2.4)ofamasterheatordirectlyfromamasterheat(See3.2.3).3.2.1.1RemeltforCastingCastingsandspecimensshallberemeltedandpouredunderinertgaspressureinaccordancewith3.2.2.1,orundervacuumwithoutlossofvacuumbetweenmeltingandpouring.3.2.1.2Ifauthorizedbypurchaser(See8.2.5),portionsoftwoormorequalifiedmasterheatsof3.2.3mayberemeltedtogetherandpouredintocastingsusingaprocedureacceptabletopurchaser.3.2.1.3Remeltforcastingshallbeperformedusingconsumableelectrodepr