BS 7371-12-2008 金属紧固件涂层.英制紧固件的要求

BS7371-12:2008Coatingsonmetalfasteners–Part12:RequirementsforimperialfastenersICS25.220.40;21.060.10NOCOPYINGWITHOUTBSIPERMISSIONEXCEPTASPERMITTEDBYCOPYRIGHTLAWBRITISHSTANDARDPublishingandcopyrightinformationTheBSIcopyrightnoticedisplayedinthisdocumentindicateswhenthedocumentwaslastissued.©BSI2008ISBN9780580609305ThefollowingBSIreferencesrelatetotheworkonthisstandard:CommitteereferenceFME/9/1Draftforcomment08/30173610DCPublicationhistoryFirstpublishedJuly2008AmendmentsissuedsincepublicationAmd.no.DateTextaffectedBS7371-12:2008--`,`,,``,```,,,`````````,``,`,,-`-`,,`,,`,`,,`---©BSI2008•iBS7371-12:2008ContentsForewordii1Scope12Normativereferences13Termsanddefinitions14Screwthreaddimensions15Coatingthickness26Applicationandtypeofcoating27Measurementofcoatingthickness2AnnexesAnnexA(informative)Stripandweighmethodforthedeterminationofgroupandsampleaverageplatingthicknessofsilver8Bibliography9ListoftablesTable1–Platingthickness2Table2–Screwsandbolts:B.S.W.andB.S.F.threads3Table3–Screwsandbolts:UNCandUNFthreads4Table4–Screwsandbolts:B.A.threads5Table5–Screwsandbolts:B.S.C.andB.S.P.threads5Table6–Nuts:B.S.W.andB.S.F.threads6Table7–Nuts:B.A.threads6Table8–Nuts:UNCandUNFthreads7SummaryofpagesThisdocumentcomprisesafrontcover,aninsidefrontcover,pagesiandii,pages1to9andabackcover.--`,`,,``,```,,,`````````,``,`,,-`-`,,`,,`,`,,`---BS7371-12:2008ii•©BSI2008ForewordPublishinginformationThisBritishStandardispublishedbyBSIandcameintoeffecton31July2008.ItwaspreparedbyTechnicalCommitteeFME/9/1,Coatingsonthreadedcomponentsandaccessories.Alistoforganizationsrepresentedonthiscommitteecanbeobtainedonrequesttoitssecretary.InformationaboutthisdocumentThisstandardsupersedesallpartsofBS3382,whicharewithdrawn.PresentationalconventionsTheprovisionsofthisstandardarepresentedinroman(i.e.upright)type.Itsrequirementsareexpressedinsentencesinwhichtheprincipalauxiliaryverbis“shall”.Commentary,explanationandgeneralinformativematerialispresentedinsmalleritalictype,anddoesnotconstituteanormativeelement.ContractualandlegalconsiderationsThispublicationdoesnotpurporttoincludeallthenecessaryprovisionsofacontract.Usersareresponsibleforitscorrectapplication.CompliancewithaBritishStandardcannotconferimmunityfromlegalobligations.©BSI2008•1BS7371-12:20081ScopeThisstandardgivesthicknessrequirementsforcoatingsonimperialmetalfastenersandcanbeusedinconjunctionwithallpartsofBS7371.NOTE1Forinformationoncoatingmaterials,seetherelevantpartofBS7371.Thisstandarddoesnotcovercomponentssuchasself-tappingscrewsandwoodscrews.Thisstandardincludesareatables(insquareinchunits)forimperialfasteners,andfactorsforthicknessdetermination(seeTable2toTable8).NOTE2Detailsconcerningcadmiumhavenotbeenincludedinthisstandardduetotherestrictionsplacedonthemarketinganduseofcadmiumanditscompoundscontainedinnationalandinternationalregulations.2NormativereferencesThefollowingreferenceddocumentsareindispensablefortheapplicationofthisdocument.Fordatedreferences,onlytheeditioncitedapplies.Forundatedreferences,thelatesteditionofthereferenceddocument(includinganyamendments)applies.BS919-1:2007,Screwgaugelimitsandtolerances–Part1:SpecificationforgaugesforscrewthreadsofunifiedformBS7371-1,Coatingsonmetalfasteners–SpecificationforgeneralrequirementsandselectionguidelinesBS7371-3,Coatingsonmetalfasteners–Part3:SpecificationforelectroplatedzinccoatingsBS7371-4,Coatingsonmetalfasteners–Part4:Specificationforelectroplatednickel,nickel/chromiumandcopper/nickel/chromiumcoatings3TermsanddefinitionsForthepurposesofthisBritishStandard,thetermsanddefinitionsgiveninBS7371-1apply.4ScrewthreaddimensionsThreaddimensionsofcomponentssuppliedforplatingandafterplatingshallconformtotherelevantscrewthreadstandards.NOTESeeBS919-1:2007,AnnexDforthegaugingproceduretobeused.Afterplating,threaddimensionsofcomponentsshallbeinaccordancewiththeappropriateclausesofBS919-1:2007,AnnexD.--`,`,,``,```,,,`````````,``,`,,-`-`,,`,,`,`,,`---BS7371-12:20082•©BSI20085CoatingthicknessThethicknesstobeappliedtoimperialfastenersmadetostandarddimensionsshallbeinaccordancewithTable1,however,ifthemaximumbatchaveragethicknessexceedsthatspecifiedinTable1,thepartscanbeacceptediftheyconformwhentestedwiththeappropriateGOgauge.6ApplicationandtypeofcoatingZincelectroplatingshallbeappliedinaccordancewithBS7371-3.Nickelornickelpluschromiumonsteelorcopperalloy(includingbrass)componentsshallbeappliedinaccordancewithBS7371-4.NOTE1Thickercoatingsarealsodealtwithintheaboveparts.NOTE2Fortinonsteel,copperandcopperalloycomponents,seeBS1872.NOTE3Forsilveronsteel,copperandcopperalloycomponents,seeBS2816.7MeasurementofcoatingthicknessCoatingthicknessshallbecalculatedinaccordancewithBS7371-3forzinccoatings,andBS7371-4fornickelandcoppercoatings.NOTE1SeeTable2toTable8forsurfaceareasofimperialfastenerswithareasinsquareinches.NOTE2ThevalueofKforareasinsquareinches(K″)isasfollows:•forzinc,K″=219,assumingadensityof7.1g/cm3;•fornickelandcopper,K″=174,assumingadensityof8.8g/cm3;•fortin(seeBS1872:1984,B.2.5)K″=212,assumingadensityof7.3g/cm3.Thesevalueswillgivethicknessinmic