1、Designation: D2596 14D2596 15Standard 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 o
2、f 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. Scope*1.1 This te
3、st method covers the determination of the load-carrying properties of lubricating greases. Three determinations aremade: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.Tester, and1.1.3 Last nonseizure load (LNSL).1.
4、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 responsibilityof the user of this standard to establish appropri
5、ate 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 on log-log paper where the coordinates are scar diamete
6、r 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 stationary balls caused by therotating ball under an applied
7、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 scar diameter at that load.3.1.3.1 Discussion1 This test
8、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 Oct. 1, 2014July 1, 2015. Published February 2015September 2015. Originally appr
9、oved in 1967. Last previous edition approved in 20102014as D2596 10D2596 14.1. DOI: 10.1520/D2596-14.10.1520/D2596-15.2 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http:/www.ansi.org.This document is not an ASTM standard and is intended
10、 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 prior editions as appropriate. In all cases only the current v
11、ersionof 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 19428-2959. United States1In this test method, the corrected l
12、oad 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 in Fig. 1 as a hertz line.3.1.5 hertz scar diameter, nthe
13、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 millimetres, andP = static applied load in kilograms-force.3.1.6
14、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. Also, initial deflection of indicating penon the optional f
15、riction-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 breakdown is noted by a sudden increase in the measured scar diam
16、eter, 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 thecompenation value at that load.3.1.8.1 DiscussionShown in Fi
17、g. 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-force (or Newtons) having intervals of approximately 0.1l
18、ogarithmic 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 weld point, nthe lowest applied load at which sliding surfac
19、es 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-pressure level of the lubricating grease has been exceeded. See F
20、ig. 1,Point D.3.1.10.2 DiscussionFIG. 1 Schematic Plot of Scar Diameter Versus Applied LoadD2596 152Some lubricating greases do not allow true welding, and extreme scoring of the three stationary balls results. In such cases, theapplied load which produces a maximum scar diameter of 4 mm is reported
21、 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 17701770 rmin 6 6060 r rpm. min. Lubricating greases are brought to 2727 C 6 8C (808 C (80 F 615F)15
22、F) and then subjected to a series of tests of 10-s10 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 properties. The resu
23、lts 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. Apparatus6.1 Four-Ball Extre
24、me-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 is designed for tes
25、ting 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.0.01 mm.6.3 Timer, graduated in tenths of a second.NOTE 2Optional equipment with Four-Ball apparatus consis
26、ts of a friction-measuring device electrically driven and conveniently graduated in10-s10 s markings.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 one test
27、 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).NOTE 3Previously, to remove the corrosion inhibitor coating on the test balls, first washing with Stod
28、dard Solvent (WarningSee 7.1.1), followedby rinsing with n-heptane (WarningSee 7.1.2), and allowing to air dry has proven to satisfactory remove the corrosion inhibitor coating. Depending3 Further details on this test method may be found in: Sayles, F. S., et al, National Lubricating Grease Institut
29、e 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, 1020 Airpark Dr., SugarGrove, IL, 60554-9585. If you are aware of alternative suppliers, please provide this
30、 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 View of Four-Ball EP TesterD2596 153on the lubricating grease chemistry, other solvents may be required to comp
31、letely remove the residual lubricating grease from the test cup assembly parts.It is up to the user of this test method to determine the solvents required to thoroughly clean the ball cup assembly parts and other parts of the test machinethat have come in contact with the lubricating grease being te
32、sted.7.1.1 Stoddard Solvent or Mineral Spirits, Reagent Grade(WarningCombustible. Health hazard.)7.1.2 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.), (0.5 in.), Grad
33、e 25 EP (Extra Polish). Such balls are described in ANSI Specifications B3.12, for Metal Balls. TheExtra-Polish finish is not described in that specification. The Rockwell C hardness shall be 64 to 66, a closer limit than is foundin the ANSI requirement.8. Preparation of Apparatus8.1 Thoroughly clea
34、n four new test balls, ball pot, and chuck assemblies by first washing with Stoddard solvent (using thesolvents selectedWarningSee 7.1.1) and then ASTM in n-heptane (WarningSee 7.1.27.1), and allow to air dry8.2 Do not use solvents such as carbon tetrachloride or other solvents that may inherently p
35、ossess extreme pressure propertieswhich may affect the results.NOTE 4Previously, users were directed to first wash the parts with Stoddard Solvent (WarningSee 7.1.1) to remove the corrosion inhibitor coating,followed by a rinse with n-heptane (WarningSee 7.1.2), and allowing to air dry. These are li
36、sted as guidance, but are not mandatory.NOTE 5Do not use solvents such as carbon tetrachloride or other solvents that may inherently possess extreme pressure properties which may affectthe results.8.2 Lower the crosshead by raising the lever arm. Lock the lever arm in the raised position by means of
37、 a locking arrangementfor that purpose.9. Procedure9.1 Bring lubricant to be tested to 2727 C 6 8C (808 C (80 F 6 15F).15 F).9.2 Completely fill the ball pot with the lubricating grease to be tested, avoiding the inclusion of air pockets. Imbed the threesteel test balls in the grease. Place the lock
38、 ring carefully over the three balls and screw down the lock nut securely (securely. 7.2).Scrape off the excess grease pushed onto the lock nut.NOTE 6Subsequent independent investigations reported in 1971 by several laboratories indicate that optimum test repeatability is obtained when theforce on t
39、he lock-down nut is maintained within the range 50 6 5 ftlbf (686 7 Nm), 50 ftlbf 6 5 ftlbf (68 Nm 6 7 Nm), applied and measured bymeans of a torque wrench. Significantly lower weld points were obtained when the force applied was approximately 100 ftlbf (136 Nm).100 ftlbf(136 Nm).9.3 Press one ball
40、into the ball chuck and 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 sho
41、ws signs ofseizure.9.5 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). 784 N(80 kgf
42、). Release the lever arm and gently apply (Note 47) the test load to the balls, making certain the ball pot assembly andmounting disk are centered. If the optional friction-measuring device is used, connect the calibrated arm on the ball pot to theindicator spring by means of the clip and wire, plac
43、ing clip and indicator support over the numbers which correspond to the appliedload.NOTE 7Shock-loading should be avoided as it may deform the balls permanently.9.7 Start the motor and run for 1010 s 6 0.2 s. 0.2 s. The time for the apparatus to “coast” to a stop is not considered.9.8 Remove the loa
44、d from the balls by raising the lever arm and locking 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
45、 release the test balls. Clean the balls with Stoddard solvent the solvents selected in7.1 and then n-heptane, and wipe dry with soft cloth. Place the individual balls on a suitable holder and by means of a microscope,measure to the nearest 0.01 mm 0.01 mm the scar diameters both parallel (horizonta
46、l) and normal (vertical) to the striations in thescar surface of one of the three test balls.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 precisi
47、on of the test. They 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 1549.9.2 Option BRetain the balls in the ball pot. Wipe excess grease from the bal
48、ls and ball pot. Wash the ball surfaces withStoddard solvent the solvents selected in 7.1 and then n-heptane. Using a microscope, measure to the nearest 0.01 mm 0.01 mmthe scar diameters both parallel (horizontal) and normal (vertical) to the striations in the scar surface of one of the three test b
49、alls.Measurement by microscope of the scar diameters on all three balls rather than one ball as outlined in OptionsAor B may be madeif the operator so desires.9.10 Record (Table 1, Column 2)5) for the 784 N (80 kgf) 784 N (80 kgf) load the average scar diameter by any one of thethreetwo techniques described in 9.9. Compare this average scar diameter (Table 1, Column 3). Discard the balls. 5) to thecompensation line average scar diameter (Table 1, Column 6). If the average scar diameter is not more than 5 % fro
