1、Designation:D259615Standard Test Method forMeasurement of Extreme-Pressure Properties of LubricatingGrease(Four-Ball Method)1This standard is issued under the fixed designation D2596;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,th
2、e 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
3、 determination of the load-carrying properties of lubricating greases.Three determina-tions are made:1.1.1 Load-Wear Index(formerly called Mean-Hertz Load),1.1.2 Weld Point,by means of the Four-Ball Extreme-Pressure(EP)Tester,and1.1.3 Last nonseizure load(LNSL).1.2 The values stated in SI units are
4、to be regarded as thestandard.The values in parentheses are for information only.1.3 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 practices and deter
5、mine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 American National Standard:2B3.12 Metal Balls3.Terminology3.1 Definitions:3.1.1 compensation line,na line of plot on log-log paperwhere the coordinates are scar diameter in millimetres andapplied load in kilogra
6、ms-force(or Newtons)obtained underdynamic conditions.3.1.1.1 DiscussionShown in Fig.1 as line ABE.3.1.2 compensation scar diameterthe average diameter,inmillimetres,of the wear scar on the stationary balls caused bythe rotating ball under an applied load in the presence of alubricant,but without cau
7、sing either seizure or welding.3.1.3 corrected load,nthe load in kilograms-force(orNewtons)obtained by multiplying the applied load by the ratioof the Hertz scar diameter to the measured scar diameter at thatload.3.1.3.1 DiscussionIn this test method,the corrected loadis calculated for each run.3.1.
8、4 hertz line,na line of plot on log-log paper where thecoordinates are scar diameter in millimetres and applied load inkilograms-force(or Newtons)obtained under static conditions.3.1.4.1 DiscussionShown in Fig.1 as a hertz line.3.1.5 hertz scar diameter,nthe average diameter,inmillimetres,of an inde
9、ntation caused by the deformation of theballs under static load(prior to test).It may be calculated fromthe equation:Dh5 8.7331022P!1/3(1)where:Dh=Hertz diameter of the contact area in millimetres,andP=static applied load in kilograms-force.3.1.6 immediate seizure region,nthat region of the scar-loa
10、d curve characterized by seizure or welding at the startup orby large wear scars.3.1.6.1 DiscussionUnder conditions of this test method,the immediate seizure region is shown by line CD.Also,initialdeflection of indicating pen on the optional friction-measuringdevice is larger than with nonseizure lo
11、ads.3.1.7 incipient seizure or initial seizure region,nthatregion at which,with an applied load,there is a momentarybreakdown of the lubricating film.3.1.7.1 DiscussionThis breakdown is noted by a suddenincrease in the measured scar diameter,shown in Fig.1 as lineBC,and a momentary deflection of the
12、 indicating pen of theoptional friction-measuring device.3.1.8 last nonseizure load,nthe last load at which themeasured scar diameter is not more than 5%greater than thecompenation value at that load.3.1.8.1 DiscussionShown in Fig.1 as Point B.3.1.9 load-wear index(or the load-carrying property of a
13、lubricant),nan index of the ability of a lubricant to minimizewear at applied loads.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricantsand is the direct responsibility ofSubcommittee D02.G0.04 on Functional Tests-Tribology.Current editio
14、n approved July 1,2015.Published September 2015.Originallyapproved in 1967.Last previous edition approved in 2014 as D2596 14.DOI:10.1520/D2596-15.2Available 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 ap
15、pears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.9.1 DiscussionUnder the conditions of this test,spe-cific loadings in kilograms-force(or Newtons)having intervalsof approximately 0.1 logarithmic units,a
16、re applied to the threestationary balls for ten runs prior to welding.The load-wearindex is the average of the sum of the corrected loadsdetermined for the ten applied loads immediately preceding theweld point.3.1.10 weld point,nthe lowest applied load at whichsliding surfaces seize and then weld.3.1.10.1 DiscussionUnder the conditions of this test,thelowest applied load in kilograms-force(or Newtons)at whichthe rotating ball seizes and then welds to the three stationaryballs,indicating the extr
