螺丝头型及垫圈种类(英文版).doc

《螺丝头型及垫圈种类(英文版).doc》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、FastenerBasicsCommonFastenerTypesFastenerMaterialsHexbolts,orhexcapscrews,areusedinmachineryandconstruction.Canbeusedwithanut,orinatappedhole.Fullythreadedhexboltsarealsoknownastapbolts.Woodscrewshavelargethreadsandasmoothshankforpullingtwopiecesofmaterialtogether.Theycanbeusedinwoodandoth

2、ersoftmateri-als.Sheetmetalscrewshavesharppointsandthreads,andaredesignedtobedrivendirectlyintosheetmetal.Theycanalsobeusedinsoftermaterialslikeplastic,fiberglass,orwood.Machinescrewsarefullythreadedforusewithanutorinatappedhole.Certaintypesaresome-timesreferredtoasstovebolts.Socketscrewsa

3、remachinescrewswithaninternalhexsocket(Allen)drive.Longerlengthsmayhaveasmoothshank.Lagbolts,orlagscrews,arelargewoodscrewswithhexheads.Typicallyusedforwoodconstructionandlandscaping.Carriageboltshavesmooth,domedheadswithasquaresectionunderneaththatpullsintothematerialtopreventspinningduri

4、nginstallation.Nutsareusedtofastenmachinethreadedfastenersinthrough-holeapplications.Locknutshelppreventloosening.Washersspreadtheloadoveragreatersurfaceareawhentighteningabolt,screwornut.Lockwashershelppreventingloosening.Tip:FindamorecomprehensivefastenertypechartGrade/Class&FastenerStre

5、ngthFastenerGrade(US)orClass(metric)referstothemechanicalproper-tiesofthefastenermaterial.Generally,ahighernumberindicatesastronger,morehardened(butalsomorebrittle)fastener.Forachartoffastenergrades,headmarkingsandmechanicalproperties,seeBoltDepot’sGrademarkingsandStrengthChartUSboltheadma

6、rkingsMetricboltheadmarkings8.810.912.9LowCarbonGrade5Grade8Class8.8Class10.9Class12.9Note:Inadditiontothesemarkings,theheadwilloftenhaveamanufacturerstamp.Note:Donotrelyonthisguideforcolor-matching.Theappearanceofthesematerialssometimesdierssignifi-cantlyfromthephotosbelow.Zinc-platedste

7、elisalowcarbonsteelforgeneraluse.Relativelyinexpensive,withthezincplatingprovidingmoderatecorrosionresistancesuitableforindoorsorotherwisedryconditions.Coloriseitherablue-ishtintoryellowdependingontheexactprocess.Hot-dippedgalvanizedsteelhasathickerzinccoating