1、Designation: D2596 10Standard 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 revisi
2、on, 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 Department of Defense.1. Scope*1.1 This test method cov
3、ers the determination of the load-carrying properties of lubricating greases. Two determinationsare made:1.1.1 Load-Wear Index (formerly called Mean-Hertz Load),and1.1.2 Weld Point, by means of the Four-Ball Extreme-Pressure (EP) Tester.1.2 The values stated in SI units are to be regarded as thestan
4、dard. 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 and health practices and determine the applica-bili
5、ty of regulatory limitations prior to use.2. Referenced Documents2.1 American National Standard:2B3.12 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 Newto
6、ns) 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
7、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 hertz
8、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.3.1.4.1 DiscussionShown in Fig. 1 as a hertz line.3.1.5 hertz scar diameter, nthe average diameter, inmillimetres, of an inden
9、tation caused by the deformation of theballs under static load (prior to test). It may be calculated fromthe equation:Dh5 8.73 3 102P!1/3(1)where:Dh= Hertz diameter of the contact area in millimetres, andP = static applied load in kilograms-force.1This test method is under the jurisdiction of ASTM C
10、ommittee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.G0.04 on Functional Tests - Tribology.Current edition approved May 1, 2010. Published June 2010. Originallyapproved in 1967. Last previous edition approved in 2008 as D259697(2008).DOI: 10.1520/D2596
11、-10.2Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.FIG. 1 Schematic Plot of Scar Diameter Versus Applied Load1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbo
12、r Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.6 immediate seizure region, nthat region of the scar-load curve characterized by seizure or welding at the startup orby large wear scars.3.1.6.1 DiscussionUnder conditions of this test method,the immediate seizure region is sh
13、own by line CD. Also, initialdeflection of indicating pen on the optional friction-measuringdevice is larger than with nonseizure loads.3.1.7 incipient seizure or initial seizure region, nthatregion at which, with an applied load, there is a momentarybreakdown of the lubricating film.3.1.7.1 Discuss
14、ionThis breakdown is noted by a suddenincrease in the measured scar diameter, shown in Fig. 1 as lineBC, and a momentary deflection of the indicating pen of theoptional friction-measuring device.3.1.8 last nonseizure load, nthe last load at which themeasured scar diameter is not more than 5 % greate
15、r than thecompenation value at that load.3.1.8.1 DiscussionShown in Fig. 1 as Point B.3.1.9 load-wear index (or the load-carrying property of alubricant), nan index of the ability of a lubricant to preventwear at applied loads.3.1.9.1 DiscussionUnder the conditions of this test, spe-cific loadings i
16、n kilograms-force (or Newtons) having intervalsof approximately 0.1 logarithmic units, are applied to the threestationary balls for ten runs prior to welding. The load wearindex is the average of the corrected loads determined for theten applied loads immediately preceding the weld point.3.1.10 weld
17、 point, nthe lowest applied load at whichsliding surfaces seize and then weld.3.1.10.1 DiscussionUnder the conditions of this test, thelowest applied load in kilograms-force (or Newtons) at whichthe rotating ball seizes and then welds to the three stationaryballs, indicating the extreme-pressure lev
18、el of the lubricatinggrease has been exceeded. See Fig. 1, Point D.3.1.10.2 DiscussionSome lubricating greases do not al-low true welding, and extreme scoring of the three stationaryballs results. In such cases, the applied load which produces amaximum scar diameter of 4 mm is reported as the weld p
19、oint.4. Summary of Test Method4.1 The tester is operated with one steel ball under loadrotating against three steel balls held stationary in the form ofa cradle. The rotating speed is 1770 6 60 rpm. Lubricatinggreases are brought to 27 6 8C (80 6 15F) and thensubjected to a series of tests of 10-s d
20、uration at increasing loadsuntil welding occurs.5. Significance and Use5.1 This test method, used for specification purposes, dif-ferentiates between lubricating greases having low, medium,and high level of extreme-pressure properties. The results donot necessarily correlate with results from servic
21、e.35.2 It is noted that lubricating greases that have as their fluidcomponent a silicone, halogenated silicone, or a mixturecomprising silicone fluid and petroleum oil, are not applicableto this method of test.6. Apparatus6.1 Four-Ball Extreme-Pressure Lubricant Tester,4illus-trated in Fig. 2.NOTE 1
22、It is important to distinguish between the Four-Ball EP Testerand the Four-Ball Wear Tester. The Four-Ball Wear Tester can be usedunder a variety of test conditions at loads up to 490 N (50 kgf). TheFour-Ball EP Tester is designed for testing under more severe conditionsand lacks the sensitivity nec
23、essary for the Four-Ball Wear Test.6.2 Microscope,4equipped with calibrated measuring scaleand readable to an accuracy of 0.01 mm.6.3 Timer, graduated in tenths of a second.NOTE 2Optional equipment with Four-Ball apparatus consists of afriction-measuring device electrically driven and conveniently g
24、raduatedin 10-s markings.7. Materials7.1 Cleaning FluidsFor preparing balls and apparatus forthe test should be those capable of removing metal preservativecoating from the balls, eliminating carryover effects from onetest to the next. The cleaning fluid selected should be non-film-forming and not c
25、ontribute to the wear or antiwear propertiesof the test lubricant (for example, chlorinated solvents shouldnot be used).7.1.1 Stoddard Solvent or Mineral Spirits, Reagent Grade(WarningCombustible. Health hazard.)7.1.2 ASTM n-heptane5(WarningFlammable. Healthhazard.)3Further details on this test meth
26、od may be found in: Sayles, F. S., et al,National Lubricating Grease Institute Spokesman, Vol 32, No. 5, August 1968, pp.162 167.4The sole source of supply of the apparatus (microscopes 103.10 A and 103.10B) known to the committee at this time is Falex Corporation, 1020 Airpark Dr.,Sugar Grove, IL,
27、60554-9585. If you are aware of alternative suppliers, pleaseprovide this information to ASTM International Headquarters. Your comments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.5Described in the 1998 Annual Book of ASTM Standards, Vo
28、l 05.04, MotorFuels, Section I, Annex 2, Section A2.7, Reference Materials.FIG. 2 Sectional View of Four-Ball EP TesterD2596 1027.2 Test Balls6Test balls shall be chrome alloy steel, madefrom AISI standard steel No. E-52100, with diameter of12.7 mm (0.5 in.), Grade 25 EP (Extra Polish). Such balls a
29、redescribed in ANSI Specifications B3.12, for Metal Balls. TheExtra-Polish finish is not described in that specification. TheRockwell C hardness shall be 64 to 66, a closer limit than isfound in the ANSI requirement.8. Preparation of Apparatus8.1 Thoroughly clean four new test balls, ball pot, andch
30、uck assemblies by first washing with Stoddard solvent(WarningSee 7.1.1) and thenASTM n-heptane (WarningSee 7.1.2), and allow to air dry.8.2 Do not use solvents such as carbon tetrachloride or othersolvents that may inherently possess extreme pressure proper-ties which may affect the results.8.3 Lowe
31、r the crosshead by raising the lever arm. Lock thelever arm in the raised position by means of a lockingarrangement for that purpose.9. Procedure9.1 Bring lubricant to be tested to 27 6 8C (80 6 15F).9.2 Completely fill the ball pot with the lubricating grease tobe tested, avoiding the inclusion of
32、air pockets. Imbed the threesteel test balls in the grease. Place the lock ring carefully overthe three balls and screw down the lock nut securely (7.2).Scrape off the excess grease pushed onto the lock nut.NOTE 3Subsequent independent investigations reported in 1971 byseveral laboratories indicate
33、that optimum test repeatability is obtainedwhen the force on the lock-down nut is maintained within the range 50 65 ftlbf (686 7 Nm), applied and measured by means of a torque wrench.Significantly lower weld points were obtained when the force applied wasapproximately 100 ftlbf (136 Nm).9.3 Press on
34、e ball into the ball chuck and mount the chuckinto chuck-holder.9.4 Examine the ball chuck carefully before each run. Thechuck is continually subjected to wear and seizure and shouldbe replaced when it will not fit into the ball chuck-holder tightenough to support its own weight, or if the ball seat
35、 showssigns of seizure.9.5 Install the ball pot assembly on the test apparatus incontact with the fourth ball. Place the mounting disk betweenball pot and thrust bearing.9.6 Place the weight tray and weights on the horizontal armin the correct notch for a base test load of 784 N (80 kgf).Release the
36、 lever arm and gently apply (Note 4) the test load tothe balls, making certain the ball pot assembly and mountingdisk are centered. If the optional friction-measuring device isused, connect the calibrated arm on the ball pot to the indicatorspring by means of the clip and wire, placing clip and indi
37、catorsupport over the numbers which correspond to the appliedload.NOTE 4Shock-loading should be avoided as it may deform the ballspermanently.9.7 Start the motor and run for 10 6 0.2 s. The time for theapparatus to “coast” to a stop is not considered.9.8 Remove the load from the balls by raising the
38、 lever armand locking it in raised position. If the friction-measuringdevice is used, remove clip and wire. Remove the ball potassembly; remove the chuck and discard the ball.9.9 Measure the scar diameter of test balls as follows:9.9.1 Option ARemove the lock nut and release the testballs. Clean the
39、 balls with Stoddard solvent and then n-heptane,and wipe dry with soft cloth. Place the individual balls on asuitable holder and by means of a microscope, measure to thenearest 0.01 mm the scar diameters both parallel (horizontal)and normal (vertical) to the striations in the scar surface of oneof t
40、he three test balls.9.9.2 Option BRetain the balls in the ball pot. Wipeexcess grease from the balls and ball pot. Wash the ballsurfaces with Stoddard solvent and then n-heptane. Using amicroscope, measure to the nearest 0.01 mm the scar diametersboth parallel (horizontal) and normal (vertical) to t
41、he striationsin the scar surface of one of the three test balls. Measurementby microscope of the scar diameters on all three balls ratherthan one ball as outlined in Options A or B may be made if theoperator so desires.9.10 Record (Table 1, Column 2) for the 784 N (80 kgf) loadthe average scar diame
42、ter by any one of the three techniquesdescribed in 9.9. Compare this average scar diameter (Table 1,Column 3). Discard the balls. If the average scar diameter isnot more than 5 % from the compensation scar diameter, repeatthe test at the next higher load (Table 1, Column 1), and againcompare scar di
43、ameters. Continue this procedure until the lastnonseizure load is determined.9.11 If the measured scar diameter for the 784 N (80 kgf)load is more than 5 % from the compensation scar diameter,the next run is made at the next lower load (Table 1, Column1). Continue this procedure until the last nonse
44、izure load isdetermined.NOTE 5When the optional friction-measuring device is used, the lastnonseizure load is detected by a gradual transverse movement of theindicating pen.9.12 Make additional runs at consecutively higher test loads(Table 1, Column 1), recording the measured scar diameter(s)and dis
45、carding test balls, until welding occurs. Make a checkrun at this point. If welding does not occur on the check run,then repeat the test at the next higher load until welding isverified.9.13 Shut off the motor immediately to prevent damage tothe tester. Excessive wear or seizure of the ball and ball
46、 chuckmay result if caution is not observed. Welding may be detectedby any or all of the following:(1) If friction-measuring device is used, a sharp transversemovement of the indicating pen.(2) Increased noise level of motor.(3) Smoking from the ball pot.(4) A sudden drop in the lever arm.6Steel bal
47、ls meeting this description were used in developing the precision of thetest. They are available from ball bearing or laboratory equipment manufacturersand distributors. All balls used in one test should be taken from one carton (of 500balls) as received from the supplier.D2596 10310. Calculations a
48、nd Reports10.1 Corrected LoadCalculate and record (Table 1, Col-umn 5) for each applied load between the last nonseizure loadand weld point using the equation:Corrected load, kgf 5 LDh/X (2)where:L = applied load, kgf, that is, total weight applied (trayand weights) multiplied by lever arm ratio,Dh=
49、 Hertz scar diameter, mm, andX = average scar diameter, mm.10.2 Load-Wear Index (see Note 6)Calculate and reportthe Load-Wear Index (formerly Mean-Hertz Load) inkilograms-force using the equation:Load2Wear Index, kgf 5 A/10 (3)where:A = sum of the corrected loads determined for the tenapplied loads immediately preceding the weld point(Note 7).NOTE 6The method of calculation was amended in 1982. For alubricant with a weld point of 400 kg or less the Load Wear Index is thesame with the old and the present method of calculation.NOTE 7If
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