Designation:A351/A351M−16StandardSpecificationforCastings,Austenitic,forPressure-ContainingParts1ThisstandardisissuedunderthefixeddesignationA351/A351M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thisspecification2coversausteniticsteelcastingsforvalves,flanges,fittings,andotherpressure-containingparts(Note1).NOTE1—Carbonsteelcastingsforpressure-containingpartsarecov-eredbySpecificationA216/A216M,low-alloysteelcastingsbySpecifi-cationA217/A217M,andduplexstainlesssteelcastingsbySpecificationA995/A995M.1.2Anumberofgradesofausteniticsteelcastingsareincludedinthisspecification.Sincethesegradespossessvaryingdegreesofsuitabilityforserviceathightemperaturesorincorrosiveenvironments,itistheresponsibilityofthepurchasertodeterminewhichgradeshallbefurnished.Selec-tionwilldependondesignandserviceconditions,mechanicalproperties,andhigh-temperatureorcorrosion-resistantcharacteristics,orboth.1.2.1Becauseofthermalinstability,GradesCE20N,CF3A,CF3MA,andCF8Aarenotrecommendedforserviceattemperaturesabove800°F[425°C].1.3Supplementaryrequirementsofanoptionalnatureareprovidedforuseattheoptionofthepurchaser.TheSupple-mentaryrequirementsshallapplyonlywhenspecifiedindi-viduallybythepurchaserinthepurchaseorderorcontract.1.4ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.1.4.1Thisspecificationisexpressedinbothinch-poundunitsandinSIunits;however,unlessthepurchaseorderorcontractspecifiestheapplicableMspecificationdesignation(SIunits),theinch-poundunitsshallapply.Withinthetext,theSIunitsa...
