ASTM_D_4684_-_20a.pdf

Designation:D468420aStandard Test Method forDetermination of Yield Stress and Apparent Viscosity ofEngine Oils at Low Temperature1This standard is issued under the fixed designation D4684;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the measurement of the yieldstress and viscosity of engine oils after cooling at controlledrates over a period exceeding 45 h to a final test temperaturebetween 10 C and 40 C.The precision is stated for testtemperatures from 40 C to 15 C.The viscosity measure-ments are made at a shear stress of 525 Pa over a shear rate of0.4 s1to 15 s1.The viscosity as measured at this shear stresswas found to produce the best correlation between the tem-perature at which the viscosity reached a critical value andborderline pumping failure temperature in engines.1.2 This test method contain two procedures:Procedure Aincorporates several equipment and procedural modificationsfrom Test Method D468402 that have shown to improve theprecision of the test,while Procedure B is unchanged from TestMethod D468402.Additionally,Procedure A applies to thoseinstruments that utilize thermoelectric cooling technology ordirect refrigeration technology of recent manufacture for in-strument temperature control.Procedure B can use the sameinstruments used in Procedure A or those cooled by circulatingmethanol.1.3 Procedure A of this test method has precision stated fora yield range from less than 35 Pa to 210 Pa and apparentviscosity range from 4300 mPas to 270 000 mPas.The testprocedure can determine higher yield stress and viscositylevels.1.4 This test method is applicable for unused oils,some-times referred to as fresh oils,designed for both light duty andheavy duty engine applications.It also has been shown to besuitable for used diesel and gasoline engine oils.The applica-bility to petroleum products other than engine oils has not beendetermined.1.5 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.5.1 ExceptionThis test method uses the SI based unit ofmilliPascal second(mPas)for viscosity which is equivalent to,centiPoise(cP).1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D3829 Test Method for Predicting the Borderline PumpingTemperature of Engine OilD8278 Specification for Digital Contact Thermometers forTest Methods Measuring Flow Properties of Fuels andLubricantsE563 Practice for Preparation and Use of an Ice-Point Bathas a Reference Temperature2.2 ISO Standard:3ISO 17025 General Requirements for the Competence ofTesting and Calibration LaboratoriesISO Guide 34 General Requirements for the Competence ofReference Material Producers3.Terminology3.1 Definitions:1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.07 on Flow Properties.Current edition approved Nov.1,2020.Published November 2020.Originallyapproved in 1987.Last previous edition approved in 2020 as D4684 20.DOI:10.1520/D4684-20A.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization(ISO),1 rue deVaremb,Case postale 56,CH-1211,Geneva 20,Switzerland,http:/www.iso.ch.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.13.1.1 apparent viscosity,nthe determined viscosity ob-tained by use of this test method.3.1.2 digital contact thermometer(DCT),