1、Designation: D5183 05 (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 ado
2、ption 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 f
3、riction 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 exactequivalents, therefor
4、e 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 standard to e
5、stablish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific warningstatements are given in 7.3-7.6.2. Referenced Documents2.1 ASTM Standards:3D4172 Test Method for Wear Preventive Characteristics ofLubricating Fluid (Four-Ball M
6、ethod)2.2 ANSI Standard: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
7、. 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 the three clamped balls for thr
8、ee-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 average 0.67 6 0.03 mm, (0.026
9、 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 98.1 N (10 kgf) at the endof e
10、ach 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 friction of lubricating fluids under
11、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 Figs. 1-3.NOTE 1It is important to distinguish between the F
12、our-Ball E.P. and1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.L0.11 on Tribiological Properties of Industrial Fluids and Lubricates.Current edition approved May 1, 2011. Published August 2011
13、. Originallyapproved in 1991. Last previous 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,
14、 please provide this information to ASTMInternational 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 servi
15、ceastm.org. For Annual Book of ASTMStandards volume 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.5The Four-Ball Wear Test Machine and the Fal
16、ex Multi-Specimen Friction andWear Test Machine, both made by Falex Corp., 1020 Airpark Dr., Sugar Grove, IL60554 have been found satisfactory for this purpose. This company can also furnisha microscope with a special base to measure the wear scars without removing theballs from the test-oil cup. Di
17、scontinued models of the Four-Ball Wear Test Machinemade by Precision Scientific Co. and Roxana Machine Works are also satisfactory.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the Four-Ball Wear Test Machine (see Test Method D417
18、2). 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 ofthe scars produced on the three balls to an accuracy of 0.01 mmwithout removal from the ball test cup.6.3 Test Balls,
19、chrome alloy steel, made from AISI 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 th
20、an is found in the ANSI requirement.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 wher
21、esuch specifications are available.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
22、/135 SUS). It should bepercolated 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. Preparatio
23、n of Apparatus8.1 Set up the 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 elap
24、sedtime, and 610 s at 10 min 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
25、392 N (15 and 40 kgf) is difficult 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 sho
26、uld be consulted for proper 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 ri
27、nse with fresh heptane.10.1.1 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 spind
28、le of thetest machine.10.3 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 theballs. Observe that this oil level still exists after the lubricantfills all of the voids in th
29、e test oil cup assembly.6Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the
30、United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Schematic of a Four-Ball Wear Test MachineFIG. 2 Falex VariableSpeed Four-Ball Wear Test MachineD5183 05 (2011)210.5 Install the test-oil cup/three balls in the machine andavoid shock lo
31、ading by slowly applying the test load 392 N (40kgf).10.6 Turn on the heaters and set controls to obtain 75 6 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
32、, start the drivemotor that was previously 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 A
33、fter the drive motor has been on for 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-bal
34、l assembly andwipe the scar area with 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 thehol
35、der. Take the second measurement along 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
36、 as wear-inscar diameter in millimetres. 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, repeate
37、d resultshould be 60.03 mm. The user 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.Repeat soak and rinse s
38、tages twice. Rinse inside of the cupwith two successive rinses of acetone using a squeeze bottle.Blow dry with nitrogen.FIG. 3 Falex Multi-Specimen Friction and Wear Test MachineTABLE 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 m
39、in 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 the friction traceD5183 05 (2011)310.12 Wipe surface of top ball and entire surface of ballchuck assembly using a clean ti
40、ssue dampened with heptane.Repeat with a tissue 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
41、 the worn-in test balls, to a level at least 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 applyin
42、g a testload of 98.1 N (10 kgf).10.16 Turn on the heater and set controls to obtain 75 6 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
43、min interval, record the torque value. Increase 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 des
44、cribed in 10.10 and note theappearance of the 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.NOT
45、E 3Current test machines are supplied with a 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
46、of friction lever arm, cm, andP = test load, 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 lev
47、er armfrom center of rotation. Test machines 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 Coefficie
48、nt of friction for each increment of 10 kgf,12.1.3 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 Re
49、peatabilityThe difference between successiveresults 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 m
