1、Designation:D250920a1Standard Test Method forMeasurement of Load-Carrying Capacity of LubricatingGrease(Timken Method)1This standard is issued under the fixed designation D2509;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year
2、 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.1NOTEEditorially improved Fig.1 in March 2021.1.Scope*1.1 This test method covers the determination of the load-carrying capacity
3、of lubricating greases by means of theTimken Extreme Pressure Tester.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It i
4、s 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.For specific warning statements,see 7.1,7.2,and 9.4.1.4 This international standard was developed in accor-danc
5、e 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 Standard
6、s:G40 Terminology Relating to Wear and Erosion3.Terminology3.1 Definitions:3.1.1 load-carrying capacity,of a lubricating grease,nthemaximum load or pressure that can be sustained by a lubricat-ing grease without failure of the sliding contact surfaces asevidenced by seizure or welding.3.1.1.1 Discus
7、sionThe values of load carrying capacity ofa lubricating grease vary according to test method.3.1.2 scoring,in tribology,na severe form of wear char-acterized by the formation of extensive grooves and scratchesin the direction of sliding.3.1.2.1 DiscussionWhen the lubricant film is substantiallymain
8、tained,a smooth scar is obtained on the test block,butwhen there is a breakdown of the lubricant film,scoring orsurface failure of the test block takes place as shown in Fig.1.In its simplest and recognized form,scoring is characterized bya wide scar on the test block and by the transfer of metal fr
9、omthe test block to the contacting surface of the test cup.The formof surface failure more usually encountered,however,consistsof a comparatively smooth scar,which shows local damagethat usually extends beyond the width of the scar.Scratches orstriations that occur in an otherwise smooth scar and th
10、at do notextend beyond the width of the scar are not considered scoringin this test method.The term scuffing is sometimes used as asynonym for scoring.3.1.3 seizure or welding,nlocalized fusion of rubbingmetal,usually indicated by streaks of transferred metal,in-creased friction and wear,or unusual
11、noise and vibration.3.1.4 wear,nthe removal of metal from a rubbing surfaceby mechanical action,or by a combination of mechanical andchemical actions.3.2 Definitions of Terms Specific to This Standard:3.2.1 extreme pressure(EP)additives,ntribologically re-active species that prevent mating metallic
12、surfaces fromadhering to each other under concentrated contact conditionswith high PV values.PV Product,G403.2.1.1 DiscussionThe PV value is the product of thecontact pressure(MPa)and sliding velocity(m/s).3.2.2 extreme pressure(EP)lubricants,nformulationswhose effects may become observable at diffe
13、rent operatingconditions,preventing adhesive wear under mixed or boundarylubrication regimes and are characterized by an increased loadcarrying capacity,or increased tribofilm strength.3.2.3 load carrying capacity,nof a lubricant,the maxi-mum PV value PV Limit,G40 that can be sustained by thelubrica
14、nt at a reported temperature without failure of thesliding contact surfaces as evidenced by adhesive wear orlocalized welding.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.G0.04 o
15、n Functional Tests-Tribology.Current edition approved Nov.15,2020.Published January 2021.Originallyapproved in 1966.Last previous edition approved in 2020 as D2509 20.DOI:10.1520/D2509-20AE01.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbo
16、r 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.13.2.3.1 DiscussionThe PV value is the product of thecontact pressure(MPa)and sliding velocity(m/s).3.2.4 OK value,nthe m
