ASTM_D_2596_-_20.pdf

Designation:D259620Standard 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,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 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 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 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:2D2509 Test Method for Measurement of Load-CarryingCapacity of Lubricating Grease(Timken Method)G40 Terminology Relating to Wear and Erosion2.2 American National Standard:3B3.12 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 kilograms-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 causing 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.3.1.4 extreme pressure(EP)additivestribologically reac-tive species that prevent mating metallic surfaces from adher-ing to each other under concentrated contact conditions withhigh PV values.PV Product,G403.1.4.1 DiscussionThe PV value is the product of thecontact pressure(MPa)and sliding velocity(m/s).D25093.1.5 extreme pressure(EP)lubricants,nformulationswhose effects may become observable at different operatingconditions,preventing adhesive wear under mixed or boundarylubrication regimes and are characterized by an increased loadcarrying capacity,or increased tribofilm strength.D25093.1.6 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.3.1.6.1 DiscussionShown in Fig.1 as a Hertz line.3.1.7 Hertz scar diameter,nthe average diameter,inmillimetres,of an indentation 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: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 edition approved May 1,2020.Published June 2020.Originallyapproved in 1967.Last previous edition approved in 2015 as D2596 15.DOI:10.1520/D2596-20.2For 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 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,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.Dh=Hertz diameter of the contact area in millimetres,andP=static applied load in kilograms-force.3.1.8 immediate seizure region,nthat region of the scar-load curve charac