ASTM-D3702-94(2009)

Designation:D3702−94(Reapproved2009)StandardTestMethodforWearRateandCoefficientofFrictionofMaterialsinSelf-LubricatedRubbingContactUsingaThrustWasherTestingMachine1ThisstandardisissuedunderthefixeddesignationD3702;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoversthedeterminationofwearrateandcoefficientoffrictionforself-lubricatedmaterialsinrubbingcontactbyatestingmachine2thatutilizesathrustwasherspecimenconfiguration.NOTE1—Thismachinemayalsobeusedtomeasurecoefficientoffriction.1.2ThevaluesinSIunitsaretoberegardedasthestandard.Incaseswherematerials,products,orequipmentareavailableonlyininch-poundunits,SIvaluesinparenthesesareforinformationonly.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.Terminology2.1Definitions:2.1.1coeffıcientoffriction,µorf—intribology—thedimen-sionlessratioofthefrictionforce(F)betweentwobodiestothenormalforce(N)pressingthesebodiestogether.µorf5~F/N!(1)2.1.1.1Discussion—Adistinctionisoftenmadebetweenstaticcoefficientoffrictionandkineticcoefficientoffriction.2.1.2wear—damagetoasolidsurface,generallyinvolvingprogressivelossofmaterial,duetorelativemotionbetweenthatsurfaceandacontactingsubstanceorsubstances.2.1.3wearrate—therateofmaterialremovalordimen-sionalchangeduetowearperunitofexposureparameter;forexample,quantityofmaterialremoved(mass,volume,thick-ness)inunitdistanceofslidingorunittime.2.2DefinitionsofTermsSpecifictoThisStandard:2.2.1torque—reactionofatendencytoturnduetofrictionforcesbetweenspecimenstravelinginacircularpath.Itistheproductofarestrainingforceandtheradiusatwhichitactstobalancethefrictionaltorque.3.SummaryofTestMethod3.1Thetestmachineisoperatedwithatestspecimenrotatingunderloadagainstastationarysteelwasher.Eachtestconsistsofbreak-infor40hfollowedbyaselectedtestduration,eachatthesameselectednormalloadandspeed.Loadisobtainedbyapplicationofdeadweightstothe10:1leverarm.Thecontactareais1.29cm2(0.20in.2).Themeanrubbingvelocityisrelatedtospindlerotationalspeed:1rpm=0.0848m/min(0.278ft/min).3.2Thethicknesschangeofthetestspecimenandtorqueduringtestaremeasuredforeachtest.3.3Wearrateincentimetresperhour(inchesperhour)andcoefficientoffrictionisreported.4.SignificanceandUse4.1Thistestmethodisusedtodeterminetheequilibriumrateofwearandcoefficientoffrictionofmaterialsinrubbingcontactunderusefuloperatingconditions,thatis,combinationsofpressureandvelocitythatfallbelowthePV(pres-sure×velocity)limitofthetestmaterial.Theuserofthistestmethodshoulddeterminetohisownsatisfactionwhethertheresultsofthistestprocedurecorrelatewithfieldperformanceorotherbenchtestmachines.Ifthetestconditionsarechanged,thewearratesmaychangeandtherelativevalueofonematerialwithrespecttoanothermayalsochange.4.2TestconditionsmaybeselectedfromTable1.4.3Theprecisionofwearmeasurementisrelativelyinde-pendentoftestdurationoramountofwear,buttheprecisionofwearrate(calculation)improveswithtestdurationandamountofwear.Itisgenerallybelievedthatusefulwearrateprecision1ThistestmethodisunderthejurisdictionofASTMCommitteeD02onPetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommitteeD02.L0.05onSolidLubricants.CurrenteditionapprovedOct.1,2009.PublishedNovember2009.Originallyapprovedin1978.Lastpreviouseditionapprovedin2004asD3702–94(2004).DOI:10.1520/D3702-94R09.2AnexampleknowntothecommitteeatthistimeistheFalexMultispecimenTestMachine,availablefromFalexCorp.,1020AirparkDrive,SugarGrove,IL60554.Thismanufacturerrecommendsamaximumtestloadof808lb(367kg).Ifyouareawareofalternativesuppliers,pleaseprovidethisinformationtoASTMInternationalHeadquarters.Yourcommentswillreceivecarefulconsiderationatameetingoftheresponsibletechnicalcommittee,1whichyoumayattend.Copyright©ASTMInternational,100BarrHarborDrive,POBoxC700,WestConshohocken,PA19428-2959.UnitedStates1CopyrightbyASTMInt'l(allrightsreserved);ThuMar703:49:05EST2013Downloaded/printedbyHuazhongUniv.ofScienceTechnologypursuanttoLicenseAgreement.Nofurtherreproductionsauthorized.char12FontTimes-BoldColorredPos1010CenteronThisstandardisforEDUCATIONALUSEONLY.requirestheselectionofatestdurationsufficienttoproduce0.1mm(0.004in.)ofwear.Testdurationswilloftenbeinthe50to4000-hrange.5.Apparatus5.1FalexMultispecimenTestMachine,Fig.1,shownsche-maticallyinFig.2anddescribedinAnnexA1.5.2TestSpecimenorRotatingWafer,showninFig.3.5.3StationaryWasher,AISIC-1018steel,showninFig.4.Thesurfacefinishshouldbe1662µin.AA,thehardnessRc2065.5.4Micrometer(Note4),capableofmeasuringtothenearest0.003mm(0.0001in.).6.ReagentsandMaterials6.1Solvent,safe,non-filmforming,nonchlorinated.NOTE2—Petroleumdistillates,formerlyusedassolvents,havebeeneliminatedduetopossibletoxiceffects.Eachusershouldselectasolvent