【英文标准名称】:StandardTestMethodforDeterminationofYieldStressandApparentViscosityofEngineOilsatLowTemperature
【原文标准名称】:发动机油在低温下表观粘度和弯曲应力测定的试验方法
【标准号】:ASTMD4684-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D02.07
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:lowtemperatureflowproperties;lowtemperatureviscosity;mini-rotaryviscometer;pumpingviscosity;useddieselengineoil;viscosity;yieldstress;Calibration--petroleumanalysisinstrumentation;Coolingcharacteristics/profiles;Fueloils;Newtonian
【摘要】:Whenanengineoiliscooled,therateanddurationofcoolingcanaffectitsyieldstressandviscosity.Inthislaboratorytest,afreshengineoilisslowlycooledthroughatemperaturerangewherewaxcrystallizationisknowntooccur,followedbyrelativelyrapidcoolingtothefinaltesttemperature.Theselaboratorytestresultshavepredictedasfailurestheknownengineoilsthathavefailedinthefieldbecauseoflackofoilpumpability.Thesedocumentedfieldfailingoilshaveallconsistedofoilsnormallytestedatx2013;25x00B0;C.Thesefieldfailuresarebelievedtobetheresultoftheoilformingagelstructurethatresultsineitherexcessiveyieldstressorviscosityoftheengineoil,orboth.CoolingProfiles:Foroilstobetestedatx2212;20x00B0;Corcolder,TableX1.1applies.ThecoolingprofiledescribedinTableX1.1isbasedontheviscositypropertiesoftheASTMPumpabilityReferenceOils(PRO).Thisseriesofoilsincludesoilswithnormallow-temperatureflowpropertiesandoilsthathavebeenassociatedwithlow-temperaturepumpabilityproblems(1-5).Significanceforthex2212;35andx2212;40x00B0;Ctemperatureprofilesisbasedonthedatacollectedfromthex201C;ColdStartingandPumpabilityStudiesinModernEnginesx201D;conductedbyASTM(6,7).Foroilstobetestedatx2212;15orx2212;10x00B0;C,TableX1.2applies.Nosignificancehasbeendeterminedforthistemperatureprofilebecauseoftheabsenceofappropriatereferenceoils.Similarly,precisionofthetestmethodusingthisprofileforthex2212;10x00B0;Ctesttemperatureisunknown.ThetemperatureprofileofTableX1.2isderivedfromtheoneinTableX1.1andhasbeenmovedupintemperature,relativetoTableX1.1,inconsiderationoftheexpectedhighercloudpointsoftheviscousoilstestedatx2212;15andx2212;10x00B0;C.1.1Thistestmethodcoversthemeasurementoftheyieldstressandviscosityofengineoilsaftercoolingatcontrolledratesoveraperiodexceeding45htoafinaltesttemperaturebetweenx2013;10andx2013;40x00B0;C.Theviscositymeasurementsaremadeatashearstressof525Paoverashearrateof0.4to15sx2013;1.Theviscosityasmeasuredatthisshearstresswasfoundtoproducethebestcorrelationbetweenthetemperatureatwhichtheviscosityreachedacriticalvalueandborderlinepumpingfailuretemperatureinengines.1.2Thistestmethodcontaintwoprocedures:ProcedureAincorporatesseveralequipmentandproceduralmodificationsfromTestMethodD4684x2013;02thathaveshowntoimprovetheprecisionofthetest,whileProcedureBisunchangedfromTestMethodD4684x2013;02.Additionally,ProcedureAappliestothoseinstrumentsthatutilizethermoelectriccoolingtechnologyordirectrefrigerationtechnologyofrecentmanufactureforinstrumenttemperaturecontrol.ProcedureBcanusethesameinstrumentsusedinProcedureAorthosecooledbycirculatingmethanol.1.3ProcedureAofthistestmethod......
【中国标准分类号】:E34
【国际标准分类号】:75_100
【页数】:13P.;A4
【正文语种】:英语