1、Designation: D 5183 05An American National StandardStandard Test Method forDetermination of the Coefficient of Friction of LubricantsUsing the Four-Ball Wear Test Machine1This standard is issued under the fixed designation D 5183; the number immediately following the designation indicates the year o
2、foriginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers a procedure for determining theco
3、efficient of friction by 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 exactequival
4、ents, therefore each system 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
5、 standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific warningstatements are given in 7.3, 7.4, 7.5, and 7.6.2. Referenced Documents2.1 ASTM Standards:3D 4172 Test Method for Wear Preventive Characteristics of
6、Lubricating Fluid (Four-Ball Method)2.2 ANSI Standard:B3.12 Specification for Metal Balls43. 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 perpendicularf
7、orce holding them in contact.4. Summary of Test Method4.1 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 t
8、he three clamped balls for three-point contact. The tem-perature 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
9、average 0.67 6 0.03 mm, (0.026 6 0.001 in.) thenthe 10 mL of test fluid 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
10、98.1 N (10 kgf) at the endof each successive 10 min interval up to the point 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 frictio
11、n of lubricating fluids under the prescribed testconditions. 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 Fig. 1, Fig. 2, and Fig. 3.NOT
12、E 1It is important to distinguish between the Four-Ball E.P. andthe Four-Ball Wear Test Machine (see Test Method D 4172). TheFour-Ball E.P. Test Machine is designed for testing under heavier loadsand lacks the sensitivity necessary for wear tests.1This test method is under the jurisdiction of ASTM C
13、ommittee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.L0 on Industrial Lubricants.Current edition approved June 1, 2005. Published July 2005. Originally approvedin 1991. Last previous edition approved in 1999 as D 518395(1999)e1.2The sole source of supp
14、ly 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 ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting
15、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 volume information, refer to the standards Document Summary page onthe ASTM website.
16、4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.5The Four-Ball Wear Test Machine and the Falex Multi-Specimen Friction andWear Test Machine, both made by Falex Corp., 1020 Airpark Dr., Sugar Grove, IL60554 have been found satisfactory for th
17、is purpose. This company can also furnisha microscope with a special base to measure the wear scars without removing theballs from the test-oil cup. Discontinued models of the Four-Ball Wear Test Machinemade by Precision Scientific Co. and Roxana Machine Works are also satisfactory.1Copyright ASTM I
18、nternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6.2 Microscope,5capable of measuring the diameters ofthe scars 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 from A
19、ISI StandardSteel No. E-52100, with diameter of 12.7 mm (0.5 in.) Grade25 EP (extra polish). Such balls are described in ANSISpecifications B3.12. The extra-polish finish is not described inthat specification. The Rockwell C hardness shall be 64 to 66,a closer limit than is found in the ANSI require
20、ment.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are availa
21、ble.6Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.7.2 Wear-In Lubricant, white oil having a viscosity at 40Cof 24.3 to 26.1 cSt (100F of 125/135 SUS). It should bepercolat
22、ed through activated alumina to remove any residualimpurities.7.3 Acetone.(WarningFlammable. Health hazard.)7.4 n-Heptane.(WarningFlammable. Health hazard.)7.5 Methyl ethyl ketone.(WarningFlammable. Healthhazard.)7.6 Pyridine.(WarningFlammable. Health hazard.)8. Preparation of Apparatus8.1 Set up th
23、e drive of the machine to obtain a spindle speedof 600 6 30 rpm.8.2 Set temperature regulator to produce a test-oil tempera-ture of 75 6 2C (167 6 4F).8.3 If an automatic timer is used to terminate a test, it shouldbe checked for the required 61 min accuracy at 60 min elapsedtime, and 610 s at 10 mi
24、n elapsed time.8.4 The loading mechanism should be balanced to a zeroreading with all parts and test oil in place. To demonstrateproper precision an addition or subtraction of 2.0 N (0.2 kgf)should be detectable in imbalance. Determination of accuracyof loading at 147 and 392 N (15 and 40 kgf) is di
25、fficult andgenerally limited to careful measurement of lever-arm ratiosand weights or piston diameter and pressure gage calibration.NOTE 2Because of differences in the construction of the variousmachines on which the four-ball can be made, the manufacturersinstructions should be consulted for proper
26、 machine set up and operation.9. Conditioning9.1 Test ConditionsSee Table 1.10. Procedure10.1 Thoroughly clean four test balls, clamping parts forupper and lower balls and the ball cup by first soaking inheptane for 1 min and then with sonic agitation for 10 s. Drainand rinse with fresh heptane.10.1
27、.1 Repeat 10.1 using acetone. Blow dry under a streamof nitrogen gas. After cleaning, handle all parts using only afresh wipe. No trace of solvent should remain when wear-inlubricant is introduced and the machine assembled.10.2 Tighten one of the clean balls into the spindle of thetest machine.10.3
28、Assemble three of the clean balls in the test-oil cup.10.4 Pour the wear-in lubricant indicated in 7.2 into thetest-oil cup to a level at least 3 mm (18 in.) above the top of the6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on
29、 the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Schematic of a Four-Ball Wear Te
30、st MachineFIG. 2 Falex VariableSpeed Four-Ball Wear Test MachineD5183052balls. Observe that this oil level still exists after the lubricantfills all of the voids in the test oil cup assembly.10.5 Install the test-oil cup/three balls in the machine andavoid shock loading by slowly applying the test l
31、oad 392 N (40kgf).10.6 Turn on the heaters and set controls to obtain 756 2C(167 6 4F). Heater voltage or offset on proportional control-lers should be capable of bringing stabilized temperaturewithin the prescribed limits.10.7 When the test temperature is reached, start the drivemotor that was prev
32、iously set to drive the top ball at 600 6 30rpm. Machines with automatic start using a proportionalcontroller will start below the set temperature. Set the propor-tional band so that test machines start at temperatures 2C(4F) below the set point temperature.10.8 After the drive motor has been on for
33、 60 6 1 min, turnoff the heaters and drive motor and remove the test-oil cup andthree-ball assembly.10.9 Measure the wear scars on the three lower balls to anaccuracy of 60.01 mm by the following method described in10.10.10.10 Drain the test oil from the three-ball assembly andwipe the scar area wit
34、h a tissue. Leave the three ballsclamped and set the assembly on a special base of a micro-scope that has been designed for the purpose. Make twomeasurements on each of the wear scars. Take one measure-ment of the scar along a radial line from the center of theholder. Take the second measurement alo
35、ng a line 90 from thefirst measurement. If a scar is elliptical take one measurementwith the striations and the other across the striations. Take careto ensure that the line of sight is perpendicular to the surfacebeing measured.Average the six readings and report as wear-inscar diameter in millimet
36、res. If the wear-in scar measures 0.676 0.03 mm, the following test sequence is performed; other-wise, the wear-in sequence is repeated using new specimenballs. (The wear-in scar can measure outside this range indifferent machines, but for a given machine, repeated resultshould be 60.03 mm. The user
37、 should first determine thewear-in average for the machine.)10.11 Add heptane to test-cup and let soak for 1 min withoccasional agitation. Drain off heptane. Rinse inside of the cupwith heptane using a squeeze bottle to remove entrained oil.FIG. 3 Falex Multi-Specimen Friction and Wear Test MachineT
38、ABLE 1 Test ConditionsWear-In TestTemperature 75 6 2C (167 6 4F) 75 6 2C (167 6 4F)Speed 600 r/min 600 r/minDuration 60 min 10 minLoad 392 N (40 kgf) per 60 min 98.1 N (10 kgf) per 10 minincrement to a load thatindicates incipient seizure(sudden increase in frictionforce value over steady state)on t
39、he friction traceD5183053Repeat soak and rinse stages twice. Rinse inside of the cupwith two successive rinses of acetone using a squeeze bottle.Blow dry with nitrogen.10.12 Wipe surface of top ball and entire surface of ballchuck assembly using a clean tissue dampened with heptane.Repeat with a tis
40、sue dampened with acetone. Blow dry withnitrogen.10.13 Wipe wear scars on the bottom three balls and weartrack on the top ball with a tissue dampened with methyl ethylketone.10.14 Pour the sample to be tested into the clean test oil cupassembly, containing the worn-in test balls, to a level at least
41、 3mm (18 in.) above the top of the balls. Observe that this oillevel exists after the lubricant fills all of the voids in the test-oilcup assembly.10.15 Install the test-oil cup containing three balls in themachine and avoid shock loading by slowly applying a testload of 98.1 N (10 kgf).10.16 Turn o
42、n the heater and set controls to obtain 756 2C(167 6 4F).10.17 When the test temperature is reached, start the drivemotor that was previously set to drive the top ball at 600 6 30rpm. Run for 10 min. Do not allow test machine to stop. At theend of the 10 min interval, record the torque value. Increa
43、se theload 98.1 N (10 kgf) every 10 min until the friction traceindicates incipient seizure is occurring. Record the torquevalue at the end of each 10 min interval.10.18 Measure the final wear scars on the three lower ballsto an accuracy of 0.01 mm as described in 10.10 and note theappearance of the
44、 wear scar.11. Calculation11.1 Determine the coefficient of friction using one of thetwo following equations: 5 0.00223 fL/P (1)where: = coefficient of friction,f = friction force, grams force,L = length of friction lever arm, cm, andP = test load, kg.NOTE 3Current test machines are supplied with a
45、friction lever armhaving a length of 7.62 cm (3 in.), and friction force is displayed in unitsof grams force. Therefore, for these instruments, = 0.0170 f/P can beused.or 5 0.00227 fL/P (2)where: = coefficient of friction,f = friction force, N,L = length of friction lever arm, cm, andP = test load,
46、kg.NOTE 4For test instruments with a lever arm of 7.62 cm (3 in.) andfriction force displayed in Newtons, = 1.73 f/P.NOTE 5Friction force is read directly from the test machine and is theforce measured at a distance equal to the length of the friction lever armfrom center of rotation. Test machines
47、may have friction force displayedas grams force or Newtons. Users should consult their operating manualsfor their equipment to verify the calculation equation.12. Report12.1 Report the following information:12.1.1 Average wear-in scar, mm,12.1.2 Coefficient of friction for each increment of 10 kgf,1
48、2.1.3 Incipient seizure load, kilogram force, and12.1.4 Final average wear scar, mm.13. Precision and Bias13.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of interlaboratory testresults is as follows:713.1.1 RepeatabilityThe difference between successiver
49、esults obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialwould, in the long run, in the normal and correct operation ofthe test method exceed the following values only in one case intwenty.Repeatability 5 0.20 3 x (3)where:x = average of successive results.13.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, exceed the following v
