ASTM D6185-1997(2008) 317 Standard Practice for Evaluating Compatibility of Binary Mixtures of Lubricating Greases.pdf

1、Designation: D 6185 97 (Reapproved 2008)An American National StandardStandard Practice forEvaluating Compatibility of Binary Mixtures of LubricatingGreases1This standard is issued under the fixed designation D 6185; the number immediately following the designation indicates the year oforiginal adopt

2、ion 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 practice covers a protocol for evaluating thecompatibility of one or

3、 three binary mixtures of lubricatinggreases by comparing their properties or performance relativeto those of the neat greases comprising the mixture.1.2 Three properties are evaluated in a primary testingprotocol using standard test methods: (1) dropping point byTest Method D 566 (or Test Method D

4、2265); (2) shearstability by Test Methods D 217, 100 000stroke workedpenetration; and (3) storage stability at elevated-temperature bychange in 60-stroke penetration (Test Method D 217). Forcompatible mixtures (those passing all primary testing), asecondary (nonmandatory) testing scheme is suggested

5、 whencircumstances indicate the need for additional testing.1.3 Sequential or concurrent testing is continued until thefirst failure. If any mixture fails any of the primary tests, thegreases are incompatible. If all mixtures pass the three primarytests, the greases are considered compatible.1.4 Thi

6、s practice applies only to lubricating greases havingcharacteristics suitable for evaluation by the suggested testmethods. If the scope of a specific test method limits testing tothose greases within a specified range of properties, greasesoutside that range cannot be tested for compatibility by tha

7、t testmethod. An exception to this would be when the testedproperty of the neat, constituent greases is within the specifiedrange, but the tested property of a mixture is outside the rangebecause of incompatibility.1.5 This practice does not purport to cover all test methodsthat could be employed.1.

8、6 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.7 This standard does not purport to address all the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropria

9、te safety andpractices and determine the applicability of regulatory limita-tions prior to use. For specific safety information, see 7.2.3.2. Referenced Documents2.1 ASTM Standards:2D 217 Test Methods for Cone Penetration of LubricatingGreaseD 566 Test Method for Dropping Point of LubricatingGreaseD

10、 972 Test Method for Evaporation Loss of LubricatingGreases and OilsD 1092 Test Method for Measuring Apparent Viscosity ofLubricating GreasesD 1263 Test Method for Leakage Tendencies ofAutomotiveWheel Bearing GreasesD 1264 Test Method for Determining the Water WashoutCharacteristics of Lubricating G

11、reasesD 1403 Test Methods for Cone Penetration of LubricatingGrease Using One-Quarter and One-Half Scale ConeEquipmentD 1478 Test Method for Low-Temperature Torque of BallBearing GreaseD 1742 Test Method for Oil Separation from LubricatingGrease During StorageD 1743 Test Method for Determining Corro

12、sion PreventiveProperties of Lubricating GreasesD 1831 Test Method for Roll Stability of LubricatingGreaseD 2265 Test Method for Dropping Point of LubricatingGrease Over Wide Temperature RangeD 2266 Test Method for Wear Preventive Characteristics ofLubricating Grease (Four-Ball Method)D 2509 Test Me

13、thod for Measurement of Load-CarryingCapacity of Lubricating Grease (Timken Method)D 2595 Test Method for Evaporation Loss of LubricatingGreases Over Wide-Temperature RangeD 2596 Test Method for Measurement of Extreme-PressureProperties of Lubricating Grease (Four-Ball Method)D 3336 Test Method for

14、Life of Lubricating Greases in BallBearings at Elevated TemperaturesD 3337 Test Method for Determining Life and Torque of1This practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.G0.01on Chemical and Genera

15、l Laboratory Tests.Current edition approved May 1, 2008. Published September 2008. Originallyapproved in 1997. Last previous edition approved in 2002 as D 618597(2002)1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annua

16、l Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Lubricating Greases in Small Ball BearingsD 3527 Test Method for Life Perform

17、ance of AutomotiveWheel Bearing GreaseD 4049 Test Method for Determining the Resistance ofLubricating Grease to Water SprayD 4170 Test Method for Fretting Wear Protection by Lubri-cating GreasesD 4175 Terminology Relating to Petroleum, PetroleumProducts, and LubricantsD 4290 Test Method for Determin

18、ing the Leakage Tenden-cies of Automotive Wheel Bearing Grease Under Acceler-ated ConditionsD 4425 Test Method for Oil Separation from LubricatingGrease by Centrifuging (Koppers Method)D 4693 Test Method for Low-Temperature Torque ofGrease-Lubricated Wheel BearingsD 4950 Classification and Specifica

19、tion for AutomotiveService GreasesD 5706 Test Method for Determining Extreme PressureProperties of Lubricating Greases Using a High-Frequency, Linear-Oscillation (SRV) Test MachineD 5707 Test Method for Measuring Friction and WearProperties of Lubricating Grease Using a High-Frequency,Linear-Oscilla

20、tion (SRV) Test Machine2.2 Federal Standard:Federal Test Method 3467.1 (Standard 791C), Storage Sta-bility of Lubricating Grease33. Terminology3.1 Definitions:3.1.1 bleed (bleeding), nof lubricating greases, the sepa-ration of a liquid lubricant from a lubricating grease for anycause.3.1.2 lubricant

21、, nany material interposed between twosurfaces that reduces the friction or wear between them.D 41753.1.3 lubricating grease, na semifluid to solid product ofa dispersion of a thickener in a liquid lubricant.3.1.3.1 DiscussionThe dispersion of the thickener forms atwo-phase system and immobilizes th

22、e liquid lubricant bysurface tension and other physical forces. Other ingredientsimparting special properties are often included. D 2173.1.4 spatulate, vto mix or blend by spreading and foldingwith a flat thin, usually metal, tool.3.1.5 syneresis, nof lubricating greases, the separation ofliquid lub

23、ricant from a lubricating grease due to shrinkage orrearrangement of the structure.3.1.5.1 DiscussionSyneresis is a form of bleeding causedby physical or chemical changes of the thickness. Separation offree oil or the formation of cracks that occur in lubricatinggreases during storage in containers

24、is most often due tosyneresis.3.1.6 thickener, nin a lubricating grease, a substancecomposed of finely divided particles dispersed in a liquidlubricant to form the products structure.3.1.6.1 DiscussionThe thickener can be fibers (such asvarious metallic soaps) or plates or spheres (such as certainno

25、n-stop thickeners) which are insoluble or, at most, only veryslightly soluble in the liquid lubricant. The general require-ments are that the solid particles be extremely small, uniformlydispersed, and capable of forming a relatively stable, gel-likestructure with the liquid lubricant. D 2173.2 Defi

26、nitions of Terms Specific to This Standard:3.2.1 compatibility, n of lubricating greases, the charac-teristic of lubricating greases to be mixed together withoutsignificant degradation of properties or performance.3.2.1.1 DiscussionWhen a mixture of two greases hasproperties or performance significa

27、ntly inferior to both of theneat, constituent greases, then the two greases are incompat-ible. If the properties are inferior to those of one neat grease butnot inferior to those of the other, then such is not necessarilyconsidered an indication of incompatibility. To be consideredsignificantly infe

28、rior, the property of the mixture would beworse than the poorer of the two neat greases by an amountexceeding the repeatability of the test method used to evaluatethe property (see pass and fail). Incompatibility most often ismanifested by a degradation in physical properties rather thanin chemical

29、properties, although, occurrence of the latter is notunknown.3.2.2 borderline compatibility, nof lubricating greases,the characteristic of lubricating greases to be mixed togetherwith only slight degradation of properties or performance.3.2.2.1 DiscussionSlight degradation means that theproperties o

30、r performance of the mixture is poorer than those ofthe two neat greases but by an amount less than the repeatabil-ity of the test method used to evaluate the property. (Seeborderline pass.)3.2.3 primary compatibility tests, nof lubricating greases,those test methods employed first to evaluate compa

31、tibility.3.2.3.1 DiscussionThe test methods considered the mostsignificant in the evaluation of grease compatibility, insofar asthey provide the most information with the least expenditure oftesting resources, include tests for dropping point, consistency(usually softening) after shearing conditions

32、, and consistencychange after storage at elevated temperatures.3.2.4 secondary compatibility tests, nof lubricatinggreases, those test methods used to evaluate compatibilitywhen the primary compatibility tests are insufficient or incon-clusive.3.2.4.1 DiscussionSuch tests are driven by the criticalf

33、eatures of a given application. For example, if the applicationsubjects the grease to water contamination, water washout orwater spray-off tests and, perhaps, corrosion tests would beused for additional evaluation. Secondary compatibility testsare suggested, but not required, by this practice.3.2.5

34、pass, nin compatibility testing of grease mixtures, atest result that is equal to or better than that of the poorer of thetwo constituent greases.3.2.6 borderline pass, n in compatibility testing of greasemixtures, a test result that is inferior to that of the poorer of thetwo constituent greases by

35、 an amount not exceeding therepeatability of the test method used for the evaluation.3Available from Standardization Documents Order Desk, Bldg. 4, Section D,700 Robbins Ave., Philadelphia, PA 191115094, Attn: NPODS.D 6185 97 (2008)23.2.6.1 DiscussionBorderline pass, borderline fail, bor-derline com

36、patible, and borderline incompatible are synony-mous terms.3.2.7 fail, nin compatibility testing of grease mixtures, atest result that is inferior to that of the poorer of the twoconstituent greases by an amount exceeding the repeatability ofthe test method used for the evaluation.3.2.8 50:50 mixtur

37、e, na uniform blend of 50 mass % ofeach of two component greases.3.2.9 10:90 mixture, na uniform blend of 10 mass % ofone grease with 90 mass % of a second grease.3.2.10 90:10 mixture, na uniform blend of 90 mass % ofone grease with 10 mass % of a second grease.4. Summary of Practice4.1 Option 1A 50

38、:50 mixture of two greases to beevaluated for compatibility is prepared by spatulating. Thismixture and the two neat, constituent greases are tested usingthe primary compatibility tests (dropping point, 100 000-strokeworked penetration, and change in 60-stroke penetration due tohigh-temperature stor

39、age). Depending on the performance ofthe mixture, relative to those of the constituent greases, 10:90and 90:10 mixtures may need to be tested in addition. Alter-natively, Option 2 can be used. Instead of testing mixtures insequential order, 10:90 and 90:10 mixtures are tested at thesame time the 50:

40、50 mixture is evaluated. If all mixtures passthe primary compatibility tests, or if the application requiresthe evaluation of specific properties, secondary compatibilitytests can be employed for further evaluation. Such tests can berun concurrently, if desired.5. Significance and Use5.1 The compati

41、bility of greases can be important for usersof grease-lubricated equipment. It is well known that themixing of two greases can produce a substance markedlyinferior to either of its constituent materials. One or more of thefollowing can occur. A mixture of incompatible greases mostoften softens, some

42、times excessively. Occasionally, it canharden. In extreme cases, the thickener and liquid lubricant willcompletely separate. Bleeding can be so severe that the mixedgrease will run out of an operating bearing. Excessive syneresiscan occur, forming pools of liquid lubricant separated from thegrease.

43、Dropping points can be reduced to the extent thatgrease or separated oil runs out of bearings at elevatedoperating temperatures. Such events can lead to catastrophiclubrication failures.5.1.1 Because of such occurrences, equipment manufactur-ers recommend completely cleaning the grease from equipmen

44、tbefore installing a different grease. Service recommendationsfor grease-lubricated equipment frequently specify the cave-atdo not mix greases under any circumstances. Despite thisadmonition, grease mixing will occur and, at times, cannot beavoided. In such instances, it would be useful to know whet

45、herthe mixing of two greases could lead to inadequate lubricationwith disastrous consequences. Equipment users most often donot have the resources to evaluate grease compatibility andmust rely on their suppliers. Mixing of greases is a highlyimprudent practice. Grease and equipment manufacturers ali

46、kerecognize such practices will occur despite all warnings to thecontrary. Thus, both users and suppliers have a need to knowthe compatibility characteristics of the greases in question.5.2 There are two approaches to evaluating the compatibil-ity of grease mixtures. One is to determine whether such

47、mixtures meet the same specification requirements as theconstituent components. This approach is not addressed by thispractice. Instead, this practice takes a specification-independent approach; it describes the evaluation of compat-ibility on a relative basis using specific test methods.5.2.1 Three

48、 test methods are used because fewer are notsufficiently definitive. For example, in one study, using100 000-stroke worked penetration for evaluation, 62 % of themixtures were judged to be compatible.4In a high-temperaturestorage stability study, covering a broader spectrum of greasetypes, only one-

49、third of the mixtures were compatible.4Thesestudies used different criteria to judge compatibility.5.2.2 Compatibility cannot be predicted with certainty fromforeknowledge of grease composition. Generally, greases hav-ing the same or similar thickener types will be compatible.Uncommonly, even greases of the same type, although nor-mally compatible when mixed, can be incompatible because ofincompatible additive treatments. Thus, compatibility needs tobe judged on a case-by-case basis.5.3 Two constituent greases are blended in specific ratios. A50:50 mixtu