saej122v002

SAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.QUESTIONSREGARDINGTHISDOCUMENT:[phone]FAX:[phone]TOPLACEADOCUMENTORDER;[phone]FAX:[phone]SAEWEBADDRESS—ThisReaffirmedDocumenthasbeenchangedonlytoreflectthenewSAETechnicalStandardsBoardFormat.ReferenceswereaddedasSection2.AllotherSectionnumbershavechangedaccordingly.1.Scope—ThisSAERecommendedPracticedefines,illustrates,andspecifiesallowablelimitsforthevarioustypesofsurfacediscontinuitiesthatmayoccurduringthemanufactureandprocessingofmetric-seriesnuts,insizes6.3to25mmandinch-seriesnutsinsizes1/4to1in,inclusive,whichareprimarilyintendedforuseinautomotiveassemblies.1.1Thebasicrecommendedpracticedoesnotincludeinspectionsamplingrequirements.Itisintendedthatthepurchasershallspecifyintheoriginalinquiryandpurchaseordertheinspectionsamplingrequirementswhichtheproducermustsatisfytodemonstratetheacceptabilityofnutswithrespecttosurfacediscontinuities.AppendixAoutlinesinspectionsamplingplansapplicablewhensuchrequirementsarenotspecifiedbythepurchaserintheoriginalinquiryandpurchaseorder.2.References2.1ApplicablePublication—Thefollowingpublicationformsapartofthisspecificationtotheextentspecifiedherein.Unlessotherwiseindicated,thelatestissueofSAEpublicationsshallapply.2.1.1ASTMPUBLICATION—AvailablefromASTM,100BarrHarborDrive,WestConshohocken,PA19428-2959.ASTMA194—SteelNutsforHighPressureandHighTemperatureService3.TypesofSurfaceDiscontinuities—Forthepurposeofthisrecommendedpractice,surfacediscontinuitiesonnutsaredividedinto11types,definedasfollows:3.1Cracks—Acrackisaclean(crystalline)fracturepassingthroughoracrossthegrainboundarieswithoutinclusionofforeignelements.Cracksarenormallycausedbyoverstressingthemetalduringforgingorotherformingoperation,orduringheattreatment.Wherepartsaresubjectedtosignificantreheating,cracksusuallyarediscoloredbyscale.3.1.1QUENCHCRACKS—Quenchcracksmayoccurduringheattreatmentduetoexcessivelyhighthermalandtransformationstresses.Theyusuallytraverseanirregularanderraticcourseonthesurfaceofthenut.TypicalquenchcracksareshowninFigure1.SAEJ122ReaffirmedMAY1998-2-FIGURE1—TYPICALQUENCHCRACKS3.1.2FORGINGCRACKS—Forgingcracksmayoccurduringthecutofforforgingoperationsandarelocatedonthetopandbottomfaceofthenut,andattheintersectionofthefaceandflat.TypicalforgingcracksareshowninFigure2.FIGURE2—TYPICALFORGINGCRACKSSAEJ122ReaffirmedMAY1998-3-3.1.3LOCKINGELEMENTFORMATIONCRACKS—Thesecracksmayoccurduetotheapplicationofpressureagainstthenutwhenintroducingthelockingelementintoprevailingtorquenuts.Cracksofthistypeareusuallylocatedinthevicinityofthelockingelementandmayeitherbeontheinternalorexternalsurface.TypicallockingelementformationcracksareshowninFigure3.FIGURE3—TYPICALLOCKINGELEMENTFORMATIONCRACKSONPREVAILING-TORQUENUTS3.1.4WASHERRETAINERCRACK—Awasherretainercrackisanopeninginaliporhubofmetalusedforcaptivatingawasheronanut.Washerretainercracksmayoccurwhenpressureisappliedtotheliporhubduringassemblyofthewasher.Suchcracksarelimitedtothecontourofthehuborlipusedforretainingpurposes.TypicalwasherretainercracksareshowninFigure4.FIGURE4—TYPICALWASHERRETAINERCRACKSSAEJ122ReaffirmedMAY1998-4-3.2Seams—Aseamisanarrowcontinuousdiscontinuityinthemetal.Seamsaregenerallyinherentintherawmaterialfromwhichthenutismade.Seamsinnutsareusuallystraightorsmoothcurvedlinediscontinuitiesrunninggenerallyparalleltothenutaxis.TypicalseamsareshowninFigure5.FIGURE5—TYPICALSEAMS3.3Bursts—Aburstisanopenbreakinthemetal.Burstsmayoccurattheperipheryofflangednuts.AtypicalburstisshowninFigure6.FIGURE6—TYPICALBURSTANDSHEARFAILURESONFLANGEDNUTSSAEJ122ReaffirmedMAY1998-5-3.4ShearFailures—Ashearfailureisanopenbreakinthemetal,locatedattheperipheryofflangednutsandapproximatelyata45degreeangletothenutaxis.Shearfailuresoccurmostfrequentlywithflangednutsandareduetooverstressingthemetalduringforging.AtypicalshearfailureisshowninFigure6.3.5Folds—Afoldisadoublingoverofmetalwhichmayoccurduringtheforgingoperation.Foldsinnutsmayoccuratorneartheintersectionofdiameterchangesoronthetoporbottomfaceofthenut.TypicalfoldsareshowninFigure7.FIGURE7—TYPICALFOLDS3.6Voids—Avoidisashallowpocketorhollowonthesurfaceofthenutduetononfillingofmetalduringforging.TypicalvoidsareshowninFigure8.FIGURE8—TYPICALVOIDSONBEARINGSURFACESSAEJ122ReaffirmedMAY1998-6-3.7ToolMarks—Toolmarksarelongitudinalorcircumferentialgroovesof