1、Designation: D 6185 97 (Reapproved 2002)e1An 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 ado
2、ption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEWarning notes were placed in the text editorially in May 2002.1. Scope1.1 Th
3、is practice covers a protocol for evaluating thecompatibility of one or 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
4、test methods: (1) dropping point byTest Method D 566 (or Test Method D 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
5、primary testing), asecondary (nonmandatory) testing scheme is suggested 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 pas
6、s the three primarytests, the greases are considered compatible.1.4 This 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 properti
7、es, greasesoutside that range cannot be tested for compatibility by that 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 pract
8、ice does not purport to cover all test methodsthat could be employed.1.6 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 appropriate safety andpractices and determine the applicabilit
9、y of regulatory limita-tions prior to use. For specific safety information, see 7.2.3.2. Referenced Documents2.1 ASTM Standards:D 217 Test Methods for Cone Penetration of LubricatingGrease2D 566 Test Method for Dropping Point of LubricatingGrease2D 972 Test Method for Evaporation Loss of Lubricating
10、Greases and Oils2D 1092 Test Method for Measuring Apparent Viscosity ofLubricating Greases2D 1263 Test Method for Leakage Tendencies ofAutomotiveWheel Bearing Greases2D 1264 Test Method for Determining Water Washout Char-acteristics of Lubricating Greases2D 1403 Test Method for Cone Penetration of L
11、ubricatingGrease Using One-Quarter and One-Half Scale ConeEquipment2D 1478 Test Method for Low-Temperature Torque of BallBearing Greases2D 1742 Test Method for Oil Separation from LubricatingGrease During Storage2D 1743 Test Method for Determining Corrosion PreventiveProperties of Lubricating Grease
12、s2D 1831 Test Method for Roll Stability of LubricatingGrease2D 2265 Test Method for Dropping Point of LubricatingGrease Over Wide Temperature Range2D 2266 Test Method for Wear Preventive Characteristics ofLubricating Grease (Four-Ball Method)2D 2509 Test Method for Measurement of Load-CarryingCapaci
13、ty of Lubricating Greases (Timken Method)2D 2595 Test Method for Evaporation Loss of LubricatingGreases over WideTemperature Range2D 2596 Test Method for Measurement of Extreme-PressureProperties of Lubricating Grease (Four-Ball Method)2D 3336 Test Method for Life of Lubricating Greases in Ball1This
14、 practice is under the jurisdiction of ASTM Committee D02 on PetroleumProducts and Lubricants and is the direct responsibility of Subcommittee D02.G onLubricating Grease.Current edition approved Nov. 10, 1997. Published January 1998.2Annual Book of ASTM Standards, Vol 05.01.1Copyright ASTM Internati
15、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Bearings at Elevated Temperatures3D 3337 Test Method for Determining Life and Torque ofLubricating Greases in Small Ball Bearings3D 3527 Test Method for Life Performance of AutomotiveWheel Bearing Grease3D 4049
16、 Test Method for Determining the Resistance ofLubricating Grease to Water Spray3D 4170 Test Method for Fretting Wear Protection by Lubri-cating Grease3D 4175 Terminology Relating to Petroleum, PetroleumProducts, and Lubricants3D 4290 Test Method for Determining the Leakage Tenden-cies of Automotive
17、Wheel Bearing Greases Under Accel-erated Conditions3D 4425 Test Method for Oil Separation from LubricatingGrease by Centrifuging (Koppers Method)3D 4693 Test Method for Low-Temperature Torque ofGrease-Lubricated Wheel Bearings3D 4950 Classification and Specification for AutomotiveService Greases3D 5
18、706 Test Method for Determining Extreme PressureProperties of Lubricating Greases Using a High-FrequencyLinear-Oscillation (SRV) Test Machine4D 5707 Test Method for Measuring Friction and WearProperties of Lubricating Grease Using a High-Frequency,Linear-Oscillation (SRV) Test Machine42.2 Federal St
19、andard:Federal Test Method Standard 791C, Method 3467.1, Stor-age Stability of Lubricating Grease53. Terminology3.1 Definitions:3.1.1 bleed (bleeding), n of lubricating greases, the sepa-ration of a liquid lubricant from a lubricating grease for anycause.3.1.2 lubricant, nany material interposed bet
20、ween 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 the liquid lubricant bysurface t
21、ension 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 lubricant from a lubricating grea
22、se 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 is most often due tosyneresis.
23、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 certainnon-stop thickeners) which are i
24、nsoluble 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 Definitions of Terms Specific to T
25、his 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 significantly inferior to both of thene
26、at, 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 inferior, the property of the mixt
27、ure 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 properties, although, occurren
28、ce 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 or performance of the mixture i
29、s 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 compatibility3.2.3.1 DiscussionThe
30、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, and consistencychange after s
31、torage 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 criticalfeatures of a given application.
32、 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 pass, nin compatibility testing
33、 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 the3Annual Book of ASTM Standards, Vol 05.02.4Annual Book of
34、 ASTM Standards, Vol 05.03.5Available from Standardization Documents Order Desk, Bldg. 4, Section D,700 Robbins Ave., Philadelphia, PA 191115094, Attn: NPODS.D 6185 97 (2002)e12two constituent greases by an amount not exceeding therepeatability of the test method used for the evaluation.3.2.6.1 Disc
35、ussionBorderline pass, borderline fail, bor-derline compatible, 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
36、 test method used for the evaluation.3.2.8 50:50 mixture, 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
37、 a second grease.4. Summary of Practice4.1 Option 1A 50:50 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 chan
38、ge in 60-stroke penetration due tohigh-temperature storage). 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, 10:9
39、0 and 90:10 mixtures are tested at thesame time the 50:50 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 concurre
40、ntly, if desired.5. Significance and Use5.1 The compatibility 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
41、mixture of incompatible greases mostoften softens, sometimes 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, formi
42、ng pools of liquid lubricant separated from thegrease. 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
43、 recommend completely cleaning the grease from equipmentbefore 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 beavoi
44、ded. In such instances, it would be useful to know whetherthe 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 highlyimp
45、rudent practice. Grease and equipment manufacturers alikerecognize 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-i
46、ty of grease mixtures. One is to determine whether suchmixtures 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
47、 relative basis using specific test methods.5.2.1 Three 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.6In a high-temperaturestorage stability study
48、, covering a broader spectrum of greasetypes, only one-third of the mixtures were compatible.6Thesestudies 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 thi
49、ckener 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 mixture simulates a ratio that might be experienced whenone grease (Grease A) is installed in a bearing containing apreviously installed, different grease (Grease B), and noattempt is made to flush out Grease B with GreaseA. The 10:90and 90:10 ratios are
