SAEJ123-1994-用于疲劳载荷的螺栓-螺钉和双头螺栓的表面不连续性

SAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.QUESTIONSREGARDINGTHISDOCUMENT:[phone]FAX:[phone]TOPLACEADOCUMENTORDER;[phone]FAX:[phone]SAEWEBADDRESS(R)SURFACEDISCONTINUITIESONBOLTS,SCREWS,ANDSTUDSINFATIGUEAPPLICATIONSForeword—ThisDocumenthasnotchangedotherthantoputitintothenewSAETechnicalStandardsBoardFormat.1.Scope—ThisSAERecommendedPracticedefines,illustrates,andspecifiesallowablelimitsforvarioustypesofsurfacediscontinuitiesthatmayoccurorbecomeapparentduringthemanufactureandprocessingofbolts,screws,andstudswhichareprimarilyintendedforuseinautomotiveassembliessubjectedtoseveredynamicstressesandnecessitatinguseofhighstrengthfastenershavingappropriatefatigue-resistantproperties.1.1Thebasicdocumentdoesnotincludeinspectionsamplingrequirements.Itisintendedthatthepurchasershallspecify,intheoriginalinquiryandpurchaseorder,theinspectionsamplingrequirementswhichtheproducermustsatisfytodemonstratetheacceptabilityofboltsandscrewswithrespecttosurfacediscontinuities.AppendixAoutlinesinspectionsamplingplansapplicablewhensuchrequirementsarenotspecifiedbythepurchaserintheoriginalinquiry,purchaseorder,orinrelatedspecifications.1.2Whentheprovisionsofthisdocumentarespecifiedbythepurchaser,thefastenermanufacturermustsignificantlyincreaseproductioncontrolsincludingmachinesetup,blankdiameters,dielubrication,in-processinspectionrequirements,andreducedproductionrate.2.References2.1ApplicablePublication—Thefollowingpublicationformsapartofthisspecificationtotheextentspecifiedherein.2.1.1ASTMPUBLICATION—AvailablefromASTM,100BarrHarborDrive,WestConshohocken,PA19428-2959.ASTME3—MethodsofPreparingMetallographicSpecimens3.TypesofSurfaceDiscontinuities—Forthepurposeofthisdocument,surfacediscontinuitiesonbolts,screws,andstudsaredividedintotentypes,definedasfollows:3.1Crack—Acrackisaclean(crystalline)fracturepassingthroughoracrossthegrainboundarieswithoutinclusionofforeignelements.Cracksarenormallycausedbyoverstressingthemetalduringforgingorotherformingoperation,orduringheattreatment.Wherepartsaresubjectedtosignificantreheating,cracksusuallyarediscoloredbyscale.SAEJ123RevisedMAR94-2-3.1.1QUENCHCRACKS—Quenchcracksmayoccurduringheattreatmentduetoexcessivelyhighthermalandtransformationstresses.Theyusuallytraverseanirregularanderraticcourseonthesurfaceofthefastener.TypicalquenchcracksareshowninFigure1.3.1.2FORGINGCRACKS—Forgingcracksmayoccurduringthecutofforforgingoperationsandarelocatedonthetopoftheheadsofscrewsandbolts.TypicalforgingcracksareshowninFigure2.3.2Seam—Seamsaregenerallyinherentintherawmaterialfromwhichfastenersaremanufactured.Theyarenarrow,generallystraightorsmooth-curvedlinediscontinuities,runninglongitudinallyontheshankand/orthread.Seamsmayextendontothetopsoftheheadsofcircularheadproductsaswellasbeingpresentattheperipheryofthehead.Seamsmayalsoextendintothechamfercircle,washerface,andwrenchingflatsofhexheadproducts.TypicalseamsareshowninFigure3.3.3Burst—Aburstisanopenbreakinthemetal(material).Burstsmayoccurontheflatsorcornersoftheheadsofboltsandscrews,attheperipheryofflangedorcircularheadproducts,orontheraisedperipheryofindentedheadboltsandscrews.TypicalburstsareshowninFigure4.3.4ShearBurst—Ashearburstisanopenbreakinthemetal,occurringmostfrequentlyattheperipheryofproductshavingcircularorflangedheadsandaregenerallylocatedatapproximately45degreestotheproductaxis.Shearburstsmayalsooccuronthesidesofhexheadproducts.TypicaldiscontinuitiesofthistypeareshowninFigure4.3.5Void—Avoidisashallowpocketorhollowonthesurfaceoftheboltorscrewduetononfillingofmetalduringforgingorupsetting.TypicalvoidsareshowninFigure5.3.6Lap—Alapisafold-overofmetalinthethreadsofscrews,bolts,andstuds.Iflapsoccur,theygenerallyshowapatternofconsistencybetweentheproduct,thatis,lapswillbeidenticallylocatedandwiththesamedirectionoftraversebetweenallproduct.TypicallapsinexternalthreadsareshowninFigure6A.3.7Fold—Afoldisadoublingoverofmetalwhichmayoccurduringtheforgingoperation.Foldsmayoccuratorneartheintersectionofdiameterchangesandareespeciallyprevalentwithnoncircularnecks,shoulders,andheads.TypicalfoldsareshowninFigure7.3.8ToolMarks—Toolmarksarelongitudinalorcircumferentialgroovesofshallowdepthproducedbythemovementofmanufacturingtoolsoverthesurfaceofthefastener.TypicaltoolmarksareshowninFigure8.3.9NickorGouge—Anickorgougeisanindentationonthesurfaceofthefastener,producedbyforcefulabrasio