GM 7112M-2005 Corrosion Protective Coatings PhosphateBlack Zinc Organic Type

《GM 7112M-2005 Corrosion Protective Coatings PhosphateBlack Zinc Organic Type》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、ENGINEERINGMaterialSpecificationGM7112MSTANDARDSMetalsCorrosionProtectiveCoatingsPhosphate/BlackZincOrganicTypehandlingpractices,partsshallnotleaveparticu-1Scopelateresidueonequipment,hands,orgloves.Thisspecificationcoversthebasicrequirements3.2Thickness.Whenappliedtothreadedprod-forano

2、noilycorrosionprotectivecoatingcon-uctsthecoatingshallnothaveanadverseeffectsistingofzincphosphatetreatment,blackzinconnormalinstallationandremovalpractices.richinorganicresincoatingandblackorganic3.2.1Thetypicalcoatingthicknessshallbe25topcoat.µm.Inthecaseofboltsandscrews,coating1.1Mat

3、erialDescription.Thecoatingsystemisthicknessshallbedeterminedatthetopofthefreeofhexavalentchromate,withnohexavalentheadatthemidpointofthelargestcontinuouschromateinfinalproductperGMW3059re-surface.quirements.GMW3034willbeusedasareferee3.2.2Themaximumthicknessofcoatingwhichtest.Thiscoati

4、ngprocessdoesnotgeneratemaybeappliedtothreadsonthreadedproductshydrogen,however,pretreatmentprocessesi.e.islimitedbythebasicthreadsize.See5.4.1acidpicklingcouldcausehydrogenabsorption.RefereeInspection.ThreadsmaybeproducedNon-electrolyticallyappliedzincrichcoatinghasundersize(beforecoat

5、ing)toaccommodatethehighpermeability,whichallowseffusionofhy-coatingthickness,providingthefinishedproductdrogenduringcuringthatmighthavebeenab-(aftercoating)meetsallspecifiedmechanicalsorbedduringacidpickling.propertiesanddimensionalrequirements.1.2UseofthisfinishonthreadedsurfacesWhere

6、mechanicalpropertiesarenotspecifiedand/orbearingsurfaceofjointscouldaffecttheundersizing/oversizingissubjecttoapprovalbytorque-tensionrelationship.Itisrecommendedthepertinentengineer.Allundersize/oversizethatatorque-tensionstudyofthefastenerjointmustbewithinpermissiblelimitsasagreedbepe

7、rformedbeforereleasingthisfinishonaupon.newapplication.3.3CorrosionResistance.Partscoatedtothisspecificationshallbecapableofwithstanding2ReferencesneutralsaltspraytestingperGM4298Pforaminimumof240h.Aftertesting,thereshallbeNote:Onlythelatestapprovedstandardsarenoredrustonsignif