Designation:E18−15AnAmericanNationalStandardStandardTestMethodsforRockwellHardnessofMetallicMaterials1,2ThisstandardisissuedunderthefixeddesignationE18;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1ThesetestmethodscoverthedeterminationoftheRockwellhardnessandtheRockwellsuperficialhardnessofmetallicmaterialsbytheRockwellindentationhardnessprin-ciple.ThisstandardprovidestherequirementsforRockwellhardnessmachinesandtheproceduresforperformingRock-wellhardnesstests.1.2Thisstandardincludesadditionalrequirementsinan-nexes:VerificationofRockwellHardnessTestingMachinesAnnexA1RockwellHardnessStandardizingMachinesAnnexA2StandardizationofRockwellIndentersAnnexA3StandardizationofRockwellHardnessTestBlocksAnnexA4GuidelinesforDeterminingtheMinimumThicknessofaTestPieceAnnexA5HardnessValueCorrectionsWhenTestingonConvexCylindricalSurfacesAnnexA61.3ThisstandardincludesnonmandatoryinformationinappendixeswhichrelatestotheRockwellhardnesstest.ListofASTMStandardsGivingHardnessValuesCorrespondingtoTensileStrengthAppendixX1ExamplesofProceduresforDeterminingRockwellHardnessUncertaintyAppendixX21.4Units—AtthetimetheRockwellhardnesstestwasdeveloped,theforcelevelswerespecifiedinunitsofkilograms-force(kgf)andtheindenterballdiameterswerespecifiedinunitsofinches(in.).ThisstandardspecifiestheunitsofforceandlengthintheInternationalSystemofUnits(SI);thatis,forceinNewtons(N)andlengthinmillimeters(mm).However,becauseofthehistoricalprecedentandcontinuedcommonusage,forcevaluesinkgfunitsandballdiametersininchunitsareprovidedforinformationandmuchofthediscussioninthisstandardreferstotheseunits.1.5Thetestprinciples,testingprocedures,andverificationproceduresareessentiallyidenticalforboththeRockwellandRockwellsuperf...
