Designation:F1941/F1941M−15StandardSpecificationforElectrodepositedCoatingsonMechanicalFasteners,InchandMetric1ThisstandardisissuedunderthefixeddesignationF1941/F1941M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.INTRODUCTIONThisspecificationcoversthecoatingofsteelunifiedinchandmetricmechanicalfastenersbyelectrodeposition.ThepropertiesofthecoatingsshallconformtotheASTMstandardsfortheindividualfinishes.ThisstandardshallbeusedinplaceofASTMB633formechanicalfasteners.Coatingthicknessvaluesarebasedonstandardtolerancesforinchandmetricexternalthreads.Thecoatingmustnotcausethebasicthreadsizetobetransgressedbyeithertheinternalorexternalthreads.ThemethodofdesignatinginchcoatedthreadsshallcomplywithASMEB1.1andISO965-1,ISO965-2,andISO965-3forISOmetriccoatedthreads.Withnormalmethodsfordepositingmetalliccoatingsfromaqueoussolutions,thereisariskofdelayedfailureduetohydrogenembrittlementforcasehardenedfastenersandfastenershavingahardnessabove39HRC.Althoughthisriskcanbemanagedbyselectingrawmaterialssuitablefortheapplicationofelectrodepositedcoatingsandbyusingmodernmethodsofsurfacetreatmentandpostheat-treatment(baking),theriskofhydrogenembrittlementcannotbecompletelyeliminated.Therefore,theapplicationofametalliccoatingbyelectrodepositionisnotrecommendedforsuchfasteners.1.Scope*1.1Thisspecificationcoversapplication,performanceanddimensionalrequirementsforelectrodepositedcoatingsonthreadedfastenerswithunifiedinchandmetricscrewthreads,butitmayalsobeappliedtootherthreadedpartsandnon-threadedpartssuchaswashersandpins.Itspecifiescoatingthickness,supplementaryhexavalentchromateornon-hexavalentconversionfinishes,corrosionresistance,precau-tionsformanagingtheriskofhydrogenembrittlementandhydrogenembrittlementreliefforhigh-strengthandsurface-hardenedfasteners.Italsohighlightsthedif...
