1、Designation:D518305(Reapproved 2011)Standard Test Method forDetermination of the Coefficient of Friction of LubricantsUsing the Four-Ball Wear Test Machine1This standard is issued under the fixed designation D5183;the number immediately following the designation indicates the year oforiginal adoptio
2、n 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.1.Scope1.1 This test method covers a procedure for determining thecoefficient of friction by
3、means of the Four-Ball Wear TestMachine.21.2 The values stated in either SI units or in the formercm-kgf metric units are to be regarded separately as thestandard.Within the text the cm-kgf units are shown inparentheses.The values stated in each system are not exactequivalents,therefore each system
4、must be used independentlyof the other.Combining values from the two systems can resultin nonconformance to specification.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-pri
5、ate safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific warningstatements are given in 7.3 7.6.2.Referenced Documents2.1 ASTM Standards:3D4172 Test Method for Wear Preventive Characteristics ofLubricating Fluid(Four-Ball Method)2.2 ANSI Standa
6、rd:4B3.12 Specification for Metal Balls3.Terminology3.1 Definitions:3.1.1 coeffcient of friction,()the ratio of the tangentialforce that is needed to start or to maintain uniform relativemotion between two contacting surfaces to the perpendicularforce holding them in contact.4.Summary of Test Method
7、4.1 Three 12.7 mm(0.5 in.)diameter steel balls are clampedtogether and covered with 10 mL of the wear-in lubricant.Afourth 12.7 mm diameter ball,referred to as the“top ball”ispressed with a force of 392 N(40 kgf)into the cavity formedby the three clamped balls for three-point contact.The tem-peratur
8、e of the wear-in lubricant is regulated at 75C(167F),and then,the top ball is rotated at 600 rpm for 60 min.4.2 Fluid is discarded and balls cleaned.The wear scardiameter on each of the lower three balls is examined.If thewear scars average 0.67 6 0.03 mm,(0.026 6 0.001 in.)thenthe 10 mL of test flu
9、id is added to the ball cup with the worn-intest balls in place.The temperature of the test lubricant isregulated at 75C(167F)and the top ball is rotated at 600 rpmat 98.1 N(10 kgf)for 10 min.4.3 The load is then increased by 98.1 N(10 kgf)at the endof each successive 10 min interval up to the point
10、 where thefrictional trace indicates incipient seizure.The coefficient offriction is measured at the end of each 10 min interval.5.Significance and Use5.1 This test method can be used to determine the coefficientof friction of lubricating fluids under the prescribed test1This test method is under th
11、e jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.L0.11 on Tribiological Properties of Industrial Fluids andLubricates.Current edition approved May 1,2011.Published August 2011.Originallyapproved in 1991.Last pre
12、vious edition approved in 2005 as D518305.DOI:10.1520/D5183-05R11.2The sole source of supply of the Four-Ball Wear Test Machine known to thecommittee at this time is Falex Corp.,1020 Airpark Dr.,Sugar Grove,IL 60554.Ifyou are aware of alternative suppliers,please provide this information to ASTMInte
13、rnational Headquarters.Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volu
14、me information,refer to the standards Document Summary page onthe ASTM website.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.Unite
15、d States1 conditions.The user of this test method should determine to hisown satisfaction whether results of this test method correlatewith field performance or other bench test machines.6.Apparatus6.1 Four-Ball Test Machine5See Figs.1-3.NOTE1It is important to distinguish between the Four-Ball E.P.
16、andthe Four-Ball Wear Test Machine(see Test Method D4172).The Four-BallE.P.Test Machine is designed for testing under heavier loads and lacks thesensitivity necessary for wear tests.6.2 Microscope,5capable of measuring the diameters of thescars produced on the three balls to an accuracy of 0.01 mmwithout removal from the ball test cup.6.3 Test Balls,chrome alloy steel,made fromAISI StandardSteel No.E-52100,with diameter of 12.7 mm(0.5 in.)Grade25 EP(extra polish).Such balls are described in ANSI
