1、Designation: D2596 101Standard 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 revis
2、ion, 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 U.S. Department of Defense.1NOTESubsection 3.1.9 was e
3、ditorially corrected in April 2014.1. Scope*1.1 This test method covers 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) Te
4、ster.1.2 The values stated in SI units are to be regarded as thestandard. 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 app
5、ro-priate safety and health practices and determine the applica-bility 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
6、diameter in millimetres andapplied load in kilograms-force (or Newtons) 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 app
7、lied load in the presence of alubricant, but without causing either 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 te
8、st method, the corrected loadis calculated for each run.3.1.4 hertz 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 he
9、rtz scar diameter, nthe average diameter, inmillimetres, of an indentation caused by the deformation of theballs under static load (prior to test). It may be calculated fromthe equation:Dh5 8.73 31022P!1/3(1)where:Dh= Hertz diameter of the contact area in millimetres, andP = static applied load in k
10、ilograms-force.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 shown by line CD. Also, initialdeflection of indicating p
11、en 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 DiscussionThis breakdown is noted by a suddenincrease in the m
12、easured 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 % greater than thecompenation value at that load.1This test met
13、hod is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility ofSubcommittee D02.G0.04 on Functional Tests - Tribology.Current edition approved May 1, 2010. Published June 2010. Originallyapproved in 1967. Last previous edition
14、 approved in 2008 as D259697(2008).DOI: 10.1520/D2596-10E01.2Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Dr
15、ive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.8.1 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 minimizewear at applied loads.3.1.9.1 DiscussionUnder the conditions of this
16、test, spe-cific loadings in 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 sum of the corrected loadsdetermined for the ten applied loads immediately
17、 preceding theweld point.3.1.10 weld 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,
18、 indicating the extreme-pressure level of the lubricatinggrease has been exceeded. See Fig. 1, Point D.3.1.10.2 DiscussionSome lubricating greases do not allowtrue welding, and extreme scoring of the three stationary ballsresults. In such cases, the applied load which produces amaximum scar diameter
19、 of 4 mm is reported as the weld point.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 thensubjec
20、ted to a series of tests of 10-s duration 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
21、correlate with results from service.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 Tes
22、ter,4illus-trated in Fig. 2.NOTE 1It 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 condi
23、tionsand lacks the sensitivity necessary 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 elec
24、trically driven and conveniently graduatedin 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 one3Further details on this test method may be foun
25、d in: Sayles, F. S., et al, NationalLubricating 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, 60554-9585. I
26、f 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.FIG. 1 Schematic Plot of Scar Diameter Versus Applied LoadFIG. 2 Sect
27、ional View of Four-Ball EP TesterD2596 1012test to the next. The cleaning fluid selected should be non-film-forming and not contribute 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 Grad
28、e(WarningCombustible. Health hazard.)7.1.2 ASTM n-heptane5(WarningFlammable. Healthhazard.)7.2 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 aredescribed in ANSI Specifications B3
29、.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, andchuck assemblies by first washing with
30、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 Lower the crosshead by raising the lever
31、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 air pockets. Imbed the threesteel tes
32、t 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 that optimum test repeatability is ob
33、tainedwhen 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 one ball into the ball chuck and mount
34、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 showssigns of seizure.9.5 Install th
35、e 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 lever arm and gently apply (Note 4)
36、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 indicatorsupport over the numbers which c
37、orrespond 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 lever armand locking it in raised po
38、sition. 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 balls with Stoddard solvent and then
39、 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 the three test balls.9.9.2 Option BRet
40、ain the balls in the ball pot. Wipe excessgrease from the balls and ball pot. Wash the ball surfaces withStoddard solvent and then n-heptane. Using a microscope,measure to the nearest 0.01 mm the scar diameters both parallel(horizontal) and normal (vertical) to the striations in the scarsurface of o
41、ne of the three test balls. Measurement by micro-scope of the scar diameters on all three balls rather than oneball as outlined in Options A or B may be made if the operatorso desires.9.10 Record (Table 1, Column 2) for the 784 N (80 kgf) loadthe average scar diameter by any one of the three techniq
42、uesdescribed 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 diameters. Continue this procedure un
43、til 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 nonseizure load isdetermined.NOTE 5When
44、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 discarding test balls, until welding o
45、ccurs. 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.5Described in the 1998 Annual Book of ASTM Standards, Vol 05.04, MotorFuels, Section I, Annex 2, Section A2.7, Reference Materials.6Steel balls meeti
46、ng 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 10139.13 Shut off the motor i
47、mmediately to prevent damage tothe tester. Excessive wear or seizure of the ball and ball 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 l
48、evel of motor.(3) Smoking from the ball pot.(4) A sudden drop in the lever arm.10. Calculations and 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 = app
49、lied load, kgf, that is, total weight applied (tray andweights) multiplied by lever arm ratio,Dh= 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:Load 2 Wear 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
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