1、Designation: D2596 101D2596 14Standard 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
2、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.This standard has been approved for use by agencies of the U.S. Department of Defense.1 NOTESubsection 3.
3、1.9 was editorially corrected in April 2014.1. Scope*1.1 This test method covers the determination of the load-carrying properties of lubricating greases. TwoThree 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-P
4、ressure (EP) Tester.1.1.3 Last nonseizure load (LNSL).1.2 The values stated in SI units are to be regarded as the standard. The values in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsi
5、bilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations 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
6、 on log-log paper where the coordinates are scar diameter in millimetres and appliedload in kilograms-force (or Newtons) obtained under dynamic conditions.3.1.1.1 DiscussionShown in Fig. 1 as line ABE.3.1.2 compensation scar diameterthe average diameter, in millimetres, of the wear scar on the stati
7、onary balls caused by therotating ball under an applied load in the presence of a lubricant, but without causing either seizure or welding.3.1.3 corrected load, nthe load in kilograms-force (or Newtons) obtained by multiplying the applied load by the ratio of theHertz scar diameter to the measured s
8、car diameter at that load.3.1.3.1 Discussion1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricantsand is the direct responsibility of SubcommitteeD02.G0.04 on Functional Tests - Tribology.Current edition approved May 1, 2010Oct. 1, 2014.
9、 Published June 2010February 2015. Originally approved in 1967. Last previous edition approved in 20082010 asD259697(2008).D2596 101. DOI: 10.1520/D2596-10E01.10.1520/D2596-14.2 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi
10、.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prio
11、r editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942
12、8-2959. United States1In this test method, the corrected load is calculated for each run.3.1.4 hertz line, na line of plot on log-log paper where the coordinates are scar diameter in millimetres and applied load inkilograms-force (or Newtons) obtained under static conditions.3.1.4.1 DiscussionShown
13、in Fig. 1 as a hertz line.3.1.5 hertz scar diameter, nthe average diameter, in millimetres, of an indentation caused by the deformation of the balls understatic load (prior to test). It may be calculated from the equation:Dh 58.7331022P!1/3 (1)where:Dh = Hertz diameter of the contact area in millime
14、tres, andP = static applied load in kilograms-force.3.1.6 immediate seizure region, nthat region of the scar-load curve characterized by seizure or welding at the startup or bylarge wear scars.3.1.6.1 DiscussionUnder conditions of this test method, the immediate seizure region is shown by line CD. A
15、lso, initial deflection of indicating penon the optional friction-measuring device is larger than with nonseizure loads.3.1.7 incipient seizure or initial seizure region, nthat region at which, with an applied load, there is a momentary breakdownof the lubricating film.3.1.7.1 DiscussionThis breakdo
16、wn is noted by a sudden increase in the measured scar diameter, shown in Fig. 1 as line BC, and a momentarydeflection of the indicating pen of the optional friction-measuring device.3.1.8 last nonseizure load, nthe last load at which the measured scar diameter is not more than 5 % greater than theco
17、mpenation 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 a lubricant), nan index of the ability of a lubricant to minimize wearat applied loads.3.1.9.1 DiscussionUnder the conditions of this test, specific loadings in kilograms
18、-force (or Newtons) having intervals of approximately 0.1logarithmic units, are applied to the three stationary balls for ten runs prior to welding. The load-wear index is the average of thesum of the corrected loads determined for the ten applied loads immediately preceding the weld point.3.1.10 we
19、ld point, nthe lowest applied load at which sliding surfaces seize and then weld.3.1.10.1 DiscussionUnder the conditions of this test, the lowest applied load in kilograms-force (or Newtons) at which the rotating ball seizes and thenwelds to the three stationary balls, indicating the extreme-pressur
20、e level of the lubricating grease has been exceeded. See Fig. 1,Point D.3.1.10.2 DiscussionFIG. 1 Schematic Plot of Scar Diameter Versus Applied LoadD2596 142Some lubricating greases do not allow true welding, and extreme scoring of the three stationary balls results. In such cases, theapplied load
21、which produces a maximum scar diameter of 4 mm is reported as the weld point.4. Summary of Test Method4.1 The tester is operated with one steel ball under load rotating against three steel balls held stationary in the form of a cradle.The rotating speed is 1770 6 60 rpm. Lubricating greases are brou
22、ght to 27 6 8C (80 6 15F) and then subjected to a seriesof tests of 10-s duration at increasing loads until welding occurs.5. Significance and Use5.1 This test method, used for specification purposes, differentiates between lubricating greases having low, medium, and highlevel of extreme-pressure pr
23、operties. The results do not necessarily correlate with results from service.35.2 It is noted that lubricating greases that have as their fluid component a silicone, halogenated silicone, or a mixturecomprising silicone fluid and petroleum oil, are not applicable to this method of test.6. Apparatus6
24、.1 Four-Ball Extreme-Pressure Lubricant Tester, 4 illustrated in Fig. 2.NOTE 1It is important to distinguish between the Four-Ball EP Tester and the Four-Ball Wear Tester. The Four-Ball Wear Tester can be used undera variety of test conditions at loads up to 490 N (50 kgf). The Four-Ball EP Tester i
25、s designed for testing under more severe conditions and lacks thesensitivity necessary for the Four-Ball Wear Test.6.2 Microscope,4equipped with calibrated measuring scale and readable to an accuracy of 0.01 mm.6.3 Timer, graduated in tenths of a second.NOTE 2Optional equipment with Four-Ball appara
26、tus consists of a friction-measuring device electrically driven and conveniently graduated in 10-smarkings.7. Materials7.1 Cleaning FluidsFor preparing balls and apparatus for the test should be those capable of removing metal preservativecoating from the balls, eliminating carryover effects from on
27、e test to the next. The cleaning fluid selected should benon-film-forming and not contribute to the wear or antiwear properties of the test lubricant (for example, chlorinated solventsshould not be used).7.1.1 Stoddard Solvent or Mineral Spirits, Reagent Grade(WarningCombustible. Health hazard.)3 Fu
28、rther details on this test method may be found in: Sayles, F. S., et al, National Lubricating Grease Institute Spokesman, Vol 32, No. 5, August 1968, pp. 162 167.4 The sole source of supply of the apparatus (microscopes 103.10 A and 103.10 B) known to the committee at this time is Falex Corporation,
29、 1020 Airpark Dr., SugarGrove, IL, 60554-9585. If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical committee,1 which you may attend.FIG. 2 Sectional Vi
30、ew of Four-Ball EP TesterD2596 1437.1.2 ASTM n-heptane5(WarningFlammable. Health hazard.)7.2 Test Balls6Test balls shall be chrome alloy steel, made from AISI standard steel No. E-52100, with diameter of 12.7 mm(0.5 in.), Grade 25 EP (Extra Polish). Such balls are described in ANSI Specifications B3
31、.12, for Metal Balls. The Extra-Polishfinish is not described in that specification. The Rockwell C hardness shall be 64 to 66, a closer limit than is found in the ANSIrequirement.8. Preparation of Apparatus8.1 Thoroughly clean four new test balls, ball pot, and chuck assemblies by first washing wit
32、h Stoddard solvent (WarningSee7.1.1) and then ASTM n-heptane (WarningSee 7.1.2), and allow to air dry.8.2 Do not use solvents such as carbon tetrachloride or other solvents that may inherently possess extreme pressure propertieswhich may affect the results.8.3 Lower the crosshead by raising the leve
33、r arm. Lock the lever arm in the raised position by means of a locking arrangementfor 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 to be tested, avoiding the inclusion of air pockets. Imbed the threesteel
34、 test balls in the grease. Place the lock ring carefully over the three balls and screw down the lock nut securely (7.2). Scrapeoff the excess grease pushed onto the lock nut.NOTE 3Subsequent independent investigations reported in 1971 by several laboratories indicate that optimum test repeatability
35、 is obtained when theforce on the lock-down nut is maintained within the range 50 6 5 ftlbf (686 7 Nm), applied and measured by means of a torque wrench. Significantlylower weld points were obtained when the force applied was approximately 100 ftlbf (136 Nm).9.3 Press one ball into the ball chuck an
36、d mount the chuck into chuck-holder.9.4 Examine the ball chuck carefully before each run. The chuck is continually subjected to wear and seizure and should bereplaced when it will not fit into the ball chuck-holder tight enough to support its own weight, or if the ball seat shows signs ofseizure.9.5
37、 Install the ball pot assembly on the test apparatus in contact with the fourth ball. Place the mounting disk between ball potand thrust bearing.9.6 Place the weight tray and weights on the horizontal arm in the correct notch for a base test load of 784 N (80 kgf). Releasethe lever arm and gently ap
38、ply (Note 4) the test load to the balls, making certain the ball pot assembly and mounting disk arecentered. If the optional friction-measuring device is used, connect the calibrated arm on the ball pot to the indicator spring bymeans of the clip and wire, placing clip and indicator support over the
39、 numbers which correspond to the applied load.NOTE 4Shock-loading should be avoided as it may deform the balls permanently.9.7 Start the motor and run for 10 6 0.2 s. The time for the apparatus to “coast” to a stop is not considered.9.8 Remove the load from the balls by raising the lever arm and loc
40、king it in raised position. If the friction-measuring deviceis used, remove clip and wire. Remove the ball pot assembly; 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 test balls. Clean the balls with Sto
41、ddard solvent and then n-heptane, andwipe dry with soft cloth. Place the individual balls on a suitable holder and by means of a microscope, measure to the nearest 0.01mm the scar diameters both parallel (horizontal) and normal (vertical) to the striations in the scar surface of one of the three tes
42、tballs.9.9.2 Option BRetain the balls in the ball pot. Wipe excess grease 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 striatio
43、ns in the scar surface of one of the three test balls. Measurement by microscopeof the scar diameters on all three balls rather than one ball as outlined in Options A or B may be made if the operator so desires.9.10 Record (Table 1, Column 2) for the 784 N (80 kgf) load the average scar diameter by
44、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 is notmore than 5 % from the compensation scar diameter, repeat the test at the next higher load (Table 1, Column 1), and again comparescar diamete
45、rs. Continue this procedure until the last nonseizure load is determined.5 Described in the 1998 Annual Book of ASTM Standards, Vol 05.04, Motor Fuels, Section I, Annex 2, Section A2.7, Reference Materials.6 Steel balls meeting this description were used in developing the precision of the test. They
46、 are available from ball bearing or laboratory equipment manufacturers anddistributors. All balls used in one test should be taken from one carton (of 500 balls) as received from the supplier.D2596 1449.11 If the measured scar diameter for the 784 N (80 kgf) load is more than 5 % from the compensati
47、on scar diameter, the nextrun is made at the next lower load (Table 1, Column 1). Continue this procedure until the last nonseizure load is determined.NOTE 5When the optional friction-measuring device is used, the last nonseizure load is detected by a gradual transverse movement of the indicatingpen
48、.9.12 Make additional runs at consecutively higher test loads (Table 1, Column 1), recording the measured scar diameter(s) anddiscarding test balls, until welding occurs. Make a check run at this point. If welding does not occur on the check run, then repeatthe test at the next higher load until wel
49、ding is verified.9.13 Shut off the motor immediately to prevent damage to the tester. Excessive wear or seizure of the ball and ball chuck mayresult if caution is not observed. Welding may be detected by any or all of the following:(1) If friction-measuring device is used, a sharp transverse movement of the indicating pen.(2) Increased noise level 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, Column 5) for each applied load
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