1、Designation:D682120aStandard Test Method forLow Temperature Viscosity of Drive Line Lubricants in aConstant Shear Stress Viscometer1This standard is issued under the fixed designation D6821;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revi
2、sion,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.1.Scope*1.1 This test method covers the measurement of the viscos-ity of drive line lubricants(gear oils,automatic tr
3、ansmissionfluids,and so forth)with a constant shear stress viscometer attemperatures from 40 C to 10 C after a prescribed preheatand controlled cooling to the final test temperature.Theprecision is stated for test temperatures from 40 C to 26 C.1.2 The applicability of this particular test method to
4、 petro-leum products other than drive line lubricants has not beendetermined.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3.1 This standard uses the SI based unit of milliPascalsecond(mPas)for viscosity which is equivale
5、nt to centiPoise(cP).1.4 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 limitati
6、ons prior to use.1.5 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 Tech
7、nicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D2983 Test Method for Low-Temperature Viscosity of Au-tomatic Transmission Fluids,Hydraulic Fluids,and Lubri-cants using a Rotational ViscometerD3829 Test Method for Predicting the Borderline PumpingTemperature of Engine
8、OilD4684 Test Method for Determination of Yield Stress andApparent Viscosity of Engine Oils at Low TemperatureD6896 Test Method for Determination of Yield Stress andApparent Viscosity of Used Engine Oils at Low Tempera-tureD8278 Specification for Digital Contact Thermometers forTest Methods Measurin
9、g Flow Properties of Fuels andLubricantsE563 Practice for Preparation and Use of an Ice-Point Bathas a Reference Temperature2.2 ISO Standards:3ISO 17025 General Requirements for the Competence ofTesting and Calibration LaboratoriesISO Guide 34 General Requirements for the Competence ofReference Mate
10、rial Producers3.Terminology3.1 Definitions:3.1.1 apparent viscosity,nthe determined viscosity ob-tained by the use of this test method.3.1.2 digital contact thermometer(DCT),nan electronicdevice consisting of a digital display and associated tempera-ture sensing probe.3.1.2.1 DiscussionThis device c
11、onsists of a temperaturesensor connected to a measuring instrument;this instrumentmeasures the temperature-dependent quantity of the sensor,computes the temperature from the measured quantity,andprovides a digital output.This digital output goes to a digitaldisplay and/or recording device that may b
12、e internal or externalto the device.3.1.2.2 DiscussionThe devices are often referred to as a“digital thermometers,”however the term includes devices thatsense temperature by means other than being in physicalcontact with the media.3.1.2.3 DiscussionPET is an acronym for portable elec-tronic thermome
13、ters,a subset of digital contact thermometers(DCT).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.
14、Originallyapproved in 2002.Last previous edition approved in 2020 as D6821 20.DOI:10.1520/D6821-20A.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 Documen
15、t Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken
16、,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.13.1.3 Newtonian oil or fluid,nan oil or fluid that at a giventemperature exhibits a constant viscosity at all shear rates orshear stresses.3.1.4 non-Newtonia
