1、Designation:D468414Standard 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 revisio
2、n,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
3、 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
4、 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:Pro
5、cedure 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 o
6、rdirect 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 a
7、pparentviscosity 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
8、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 use
9、s 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 and health pr
10、actices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D3829 Test Method for Predicting the Borderline PumpingTemperature of Engine OilE563 Practice for Preparation and Use of an Ice-Point Bathas a Reference TemperatureE644 Test Meth
11、ods for Testing Industrial Resistance Ther-mometersE1137 Specification for Industrial Platinum Resistance Ther-mometersE2877 Guide for Digital Contact Thermometers2.2 ISO Standard:3ISO 17025 General Requirements for the Competence ofTesting and Calibration LaboratoriesISO Guide 34 General Requiremen
12、ts for the Competence ofReference Material Producers3.Terminology3.1 Definitions:3.1.1 apparent viscosity,nthe determined viscosity ob-tained by use of this test method.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direc
13、t responsibility ofSubcommittee D02.07 on Flow Properties.Current edition approved July 1,2014.Published August 2014.Originallyapproved in 1987.Last previous edition approved in 2012 as D4684 12.DOI:10.1520/D4684-14.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Cu
14、stomer 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 S
15、ummary 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 States1 3.1.2 Digital Contact Thermometer(DCT),nan electronicdevice consisting of a digital display and associated tempera-ture sensing p
16、robe.3.1.2.1 DiscussionThis device consists 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 or display,or both,of the temperature.The temperature sensing probe is in contact with the materialwhose temperature is being measured.This device is some-times referred to as a digital thermometer.NOTE1Portable electronic thermometers(PET)is
