Designation:A618/A618M−04(Reapproved2015)StandardSpecificationforHot-FormedWeldedandSeamlessHigh-StrengthLow-AlloyStructuralTubing1ThisstandardisissuedunderthefixeddesignationA618/A618M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope1.1Thisspecificationcoversgradesofhot-formedweldedandseamlesshigh-strengthlow-alloysquare,rectangular,round,orspecialshapestructuraltubingforwelded,riveted,orboltedconstructionofbridgesandbuildingsandforgeneralstructuralpurposes.Whenthesteelisusedinweldedconstruction,theweldingprocedureshallbesuitableforthesteelandtheintendedservice.1.2GradeIIhasatmosphericcorrosionresistanceequiva-lenttothatofcarbonsteelwithcopper(0.20minimumCu)GradesIaandIbhaveatmosphericcorrosionresistancesub-stantiallybetterthanthatofGradeII(Note1).Whenproperlyexposedtotheatmosphere,GradesIaandIbcanbeusedbare(unpainted)formanyapplications.Whenenhancedcorrosionresistanceisdesired,GradeIII,copperlimitsmaybespecified.NOTE1—Formethodsofestimatingtheatmosphericcorrosionresis-tanceoflowalloysteelsseeGuideG101oractualdata.1.3ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.Withinthetext,theSIunitsareshowninbrackets.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedindependentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.2.ReferencedDocuments2.1ASTMStandards:2A370TestMethodsandDefinitionsforMechanicalTestingofSteelProductsA700GuideforPackaging,Marking,andLoadingMethodsforSteelProductsforShipmentA751TestMethods,Practices,andTerminologyforChemi-calAnalysisofSteelProductsG101GuideforEstimatingtheAtmosphericCorrosionRe-sistanceofLow-AlloySteels3.OrderingInformation3.1Ordersformaterial...
