Designation:A859/A859M−04(Reapproved2014)StandardSpecificationforAge-HardeningAlloySteelForgingsforPressureVesselComponents1ThisstandardisissuedunderthefixeddesignationA859/A859M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thisspecificationcoversrequirementsforlow-carbonage-hardeningnickel-copper-chromium-molybdenum-columbiumalloysteelforgingsforpressurevesselcompo-nents.1.2ForgingsunderthisspecificationareavailableasGradesAorB.GradeAmaybeorderedinoneortwoclassesasfollows:1.2.1GradeAClass1—Normalized-and-precipitation-heat-treated,providingaminimumyieldstrengthof55ksi[380MPa]andaminimumtensilestrengthof65ksi[450MPa].1.2.2GradeAClass2—Quenched-and-precipitation-heat-treated,providingaminimumyieldstrengthof65ksi[450MPa]andaminimumtensilestrengthof75ksi[MPa].1.2.3GradeAwastheoriginalsteelcompositioninthisspecification.1.3Althoughthematerialisreadilyweldable,weldingproceduresareoffundamentalimportanceandmustbesuchasnottoaffectadverselythepropertiesofthematerial,especiallyintheheat-affectedzone.Itispresupposedthatweldingprocedureswillbesuitableforthematerialbeingwelded.1.4Supplementaryrequirements,includingthoseapplicableinSpecificationA788/A788M,areprovidedforusewhenadditionaltestingorinspectionisdesired.Theseshallapplyonlywhenspecifiedindividuallybythepurchaserintheorder.1.5ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.1.6Thisspecificationisexpressedinbothinch-poundandSIunits.However,unlesstheorderspecifiestheapplicable“M”specificationdesignation[SIunits],thematerialshallbefurnishedtoinch-poundunits.2.ReferencedDocuments2.1ASTMS...
