BS 970-2 1988

BRITISHSTANDARDBS970-2:1988IncorporatingAmendmentNos.1and2SpecificationforWroughtsteelsformechanicalandalliedengineeringpurposes—Part2:RequirementsforsteelsforthemanufactureofhotformedspringsUDC669.14-131:[669-122.4:669-15:669.018.27]:001.2LicensedCopy:InstituteOfTechnologyTallaght,InstituteofTechnology,FriJul2010:07:34GMT+00:002007,UncontrolledCopy,(c)BSIBS970-2:1988ThisBritishStandard,havingbeenpreparedunderthedirectionoftheIronandSteelStandardsCommittee,waspublishedundertheauthorityoftheBoardofBSIandcomesintoeffecton31October1988©BSI12-1998FirstpublishedJuly1941FirstrevisionOctober1942SecondrevisionMarch1947ThirdrevisionJanuary1955Fourthrevision,asPart5,June1972Fifthrevision,asPart2,October1988ThefollowingBSIreferencesrelatetotheworkonthisstandard:CommitteereferenceISM/31Draftforcomment87/36929DCISBN0580168697CommitteesresponsibleforthisBritishStandardThepreparationofthisBritishStandardwasentrustedbytheIronandSteelStandardsCommittee(ISM/-)toTechnicalCommitteeISM/31,uponwhichthefollowingbodieswererepresented:BritishChainManufacturers’AssociationBritishCoalBritishForgingIndustryAssociationBritishIndustrialFastenersFederationBritishRailBritishSteelIndustryColdRolledSectionsAssociationDepartmentofTradeandIndustry(NationalPhysicalLaboratory)EngineeringIndustries’AssociationFederationofBritishEngineers’ToolManufacturersInstitutionofProductionEngineersLloydsRegisterofShippingMinistryofDefenceNationalAssociationofSteelStockholdersRoadVehicleSpringSocietySocietyofBritishAerospaceCompaniesLimitedSocietyofMotorManufacturersandTradersLimitedStainlessSteelFabricators’AssociationofGreatBritainThefollowingbodieswerealsorepresentedinthedraftingofthestandard,throughsub-committeesandpanels:SpringResearchandManufacturers’AssociationAmendmentsissuedsincepublicationAmd.No.DateofissueComments6190August,19896942February,1992IndicatedbyasidelineinthemarginLicensedCopy:InstituteOfTechnologyTallaght,InstituteofTechnology,FriJul2010:07:34GMT+00:002007,UncontrolledCopy,(c)BSIBS970-2:1988©BSI12-1998iContentsPageCommitteesresponsibleInsidefrontcoverForewordii1Scope12Definitions13General14Informationtobesuppliedbythepurchaser15Steelmakingprocessesandcastingmethods16Chemicalcomposition17Freedomfromdefects48Surfacecondition49Conditionofmaterialondespatch410Physicalproperties411Selectionandtestingofspecimens412Formofsection613Marking7AppendixAOptions10AppendixBRecommendedmaximumdimensionsforflatsandrounds10Figure1—Positionsfordecarburizationmeasurements6Figure2—Edgeprofilesforflats7Figure3—Dimensionsofribandgroovespringsteelforplates9.52mmthickandover8Table1—Steelstorestrictedchemicalcompositionranges.Chemicalcomposition2Table2—Compositionofsteelstohardenabilityrequirements.Chemicalcomposition2Table3—Limitsonresidualelements3Table4—Permitteddeviationsfromspecifiedrangeonproductanalysis3Table5—Maximumacceptabledepthforlongitudinaldefectsonhot-rolledordrawnbar4Table6—Maximumlevelsoffunctionaldecarburizationforhot-rolledordrawnflats5Table7—Steelstohardenabilityrequirements5Table8—Averagemaximuminclusionlevels5Table9—Normalizingandaustenitizingtemperaturesforhardenabilitytests6Table10—Tolerancesonwidthandthicknessforflats8Table11—Tolerancesonconcavity,convexityandparallelismacrossthewidthforflats8Table12—Diameterandovalitytoleranceforroundbars9Table13—Recommendedmaximumdimensionsforflatsandrounds10PublicationsreferredtoInsidebackcoverLicensedCopy:InstituteOfTechnologyTallaght,InstituteofTechnology,FriJul2010:07:34GMT+00:002007,UncontrolledCopy,(c)BSIBS970-2:1988ii©BSI12-1998ForewordThisPartofBS970hasbeenpreparedunderthedirectionoftheIronandSteelStandardsCommittee.ItformsPart2ofarestructuredBS970andisarevisionofBS970-5:1972,incorporatingtherequirementsofBS24-3A:1959.Boththesestandardsarewithdrawn.TherestructuredBS970consistsofthreeParts.Part1specifiesgeneralinspectionandtestingproceduresandspecificrequirementsforcarbon,carbonmanganese,alloyandstainlesssteelsandwaspublishedin1983.BS970-4waspublishedin1970andspecifiesrequirementsforvalvesteels.NewsteelshavebeenintroducedinthisPartofBS970toreflectchangesinspringmanufacture,theneedforfine-grainedsteelsand,forcertainapplications,closelycontrolledhardenability.Requirementshavealsobeenintroducedforaveragemaximumlevelsofnon-metallicinclusionsforalltypesofbarandfordepthsofdecarburizationandsurfacedefectsonhotrolledordrawnbar.ThedimensionalanddecarburizationtolerancesinthisPartofBS970applyonlytomaterialsupplieddirectlytothespringmakerandnottointermediateproducts.ThecarbonsteelsforgeneralapplicationshavebeenremovedinthisrevisionastheyarealreadycoveredinTable2ofBS970-1:1983(grades080A67and060A78).AnumberoforderingoptionsislistedinappendixA.Theseshouldbecalledupbythepurchaserasrequired.Assessedcapability.UsersofthisBritishStandardareadvisedtoconsiderthedesirabilityofassessmentandregistrationofasupplier’squalitysystemsagainsttheappropriatePartofBS5750byathirdpartycertificationbody.ABritishStandarddoesnotpurporttoincludeallthenecessaryprovisionsofacontract.UsersofBritishStandardsareresponsiblefortheircorrec