1、Designation: F 2161 01Standard Guide forInstrument and Precision Bearing LubricantsPart 1 Oils1This standard is issued under the fixed designation F 2161; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide is a tool to aid in the choice of an oil forprecision rolling element bearing applications. There are twoareas where this
3、guide should have the greatest impact: (1)when a lubricant is being chosen for a new bearing applicationand (2) when a lubricant for a bearing has to be replacedbecause the original lubricant specified for the bearing can nolonger be obtained. The Report (Section 5) contains a series oftests perform
4、ed by the same laboratory on a wide variety of oilscommonly used in bearing applications to allow comparisonsof those properties of the oil that the committee thought to bemost important when making a choice of lubricant. This guidecontains a listing of the properties of oils by chemical type, thati
5、s, ester, silicone, and so forth. This organization is necessarysince the operational requirements in a particular bearingapplication may limit the choice of lubricant to a particularchemical type due to its temperature stability, viscosity indexor temperature-vapor pressure characteristics, and so
6、forth. TheReport includes the results of tests on the oils included in thisstudy. The Report recommends replacement lubricants forthose oils tested that are no longer available. The Report alsoincludes a glossary of terms used in describing/discussing thelubrication of precision and instrument beari
7、ngs. The Reportpresents a discussion of elastohydrodynamic lubrication asapplied to rolling element bearings.1.2 Although other compendia of lubricant properties havebeen published, for example, the Barden Product Standard,Lubricants2and the NASA Lubricant Handbook for the SpaceIndustry3, none have
8、centered their attention on lubricantscommonly used in precision rolling element bearings (PREB).The PREB put a host of unique requirements upon a lubricant.The lubricant must operate at both high and low temperatures.The lubricant must provide lubrication for months, if not years,without replenishm
9、ent. The lubricant must be able to supporthigh loads but cannot be so viscous that it will interfere withthe operation of the bearing at very high speeds or lowtemperatures, or both. The lubricant must provide boundarylubrication during low-speed or intermittent operation of thebearing. And, in many
10、 applications, its vapor pressure must below enough under operating conditions that evaporative lossesdo not lead to lubricant depletion or contamination of nearbycomponents. These and other considerations dictated the seriesof tests that were performed on each lubricant included in thisstudy.1.3 An
11、other important consideration was encompassed inthis study. Almost all of the testing was performed by the samelaboratory, The Petroleum Products Research Department ofthe Southwest Research Institute in San Antonio, Texas, usingASTM procedures. This continuity of testing should form asolid basis fo
12、r comparing the properties of the multitude oflubricants tested by avoiding some of the variability introducedwhen lubricants are tested by different laboratories usingdifferent or even the “same” procedures.1.4 It should be noted that no functional tests (that is,bearing tests) were performed. The
13、results of the four-ball weartest give some comparison, “a figure of merit,” of the lubrica-tion properties of the oils under the condition of this test. Butexperience has shown that testing the lubricant in runningbearings is the best means of determining lubricant perfor-mance.2. Referenced Docume
14、nts2.1 ASTM Standards:D 92 Test Method for Flash and Fire Points by ClevelandOpen Cup4D 97 Test Method for Pour Point of Petroleum Products4D 445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (the Calculation of Dynamic Viscos-ity)4D 974 Standard Test Method for Acid and Base
15、Number byColor Indicator Titration45D 972 Test Method for Evaporation Loss of LubricatingGreases and Oils4D 1331 Test Methods for Surface and Interfacial Tension ofSolutions of Surface-Active Agents61This guide is under the jurisdiction of ASTM Committee F34 on RollingElement Bearings and is the dir
16、ect responsibility of Subcommittee F34.02 onTribology.Current edition approved Dec. 10, 2001. Published February 2002.2“Product Standard, Lubricants,” available from The Barden Corp., Danbury,CT.3NASA Lubricant Handbook for the Space Industry, Ernest L. McMurtrey, NASATechnical Memorandum TM-86556,
17、George C. Marshall Space Flight Center,National Aeronautics and Space Administration, December 1985.4Annual Book of ASTM Standards, Vol 05.01.5Discontinued 1959; replaced by D 1663.6Annual Book of ASTM Standards, Vol 15.04.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consh
18、ohocken, PA 19428-2959, United States.D 2270 Practice for Calculating Viscosity Index from Kine-matic Viscosity at 40 and 100C4D 4172 Test Method for Wear Preventive Characteristics ofLubricating Fluid (Four-Ball Method)72.2 Government Documents8:MIL-DTL-53131 Lubricating Oil, Precision Rolling Ele-
19、ment Bearing, Plolyalphaolefin BasedMIL-L-6085 Lubricating Oil, Aircraft Turbine Engine, Syn-thetic BaseMIL-L-14107 Lubricating Oil, Weapons, Low TemperatureMIL-L-23699 Lubricating Oil, Aircraft Turbine Engines,Synthetic BaseMIL-L-7808 Lubricating Oil, Aircraft Turbine Engine, Syn-thetic BaseMIL-L-8
20、1846 Lubricating Oil, Instrument, Ball Bearing,High Flash PointMIL-S-81087 Silicone, Fluid, Chlorinated Phenyl MethylPolysiloxane3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ABEC, nAnnular Bearing Engineers Committee ofthe American Bearing Manufacturers Association (ABMA).T
21、he ABEC establishes bearing tolerance classes. Precisionbearings are ABEC 5P and ABEC-5T and higher.3.1.2 absolute viscosity (h), n(sometimes called dynamicviscosity or just viscosity)a measure of the tendency of thefluid to resist shear. The elastohydrodynamic theory (EHD)film thickness and torque
22、losses in a ball bearing are verystrong functions of h. Since the ratio of absolute viscosity todensity, h/r, appears frequently in hydrodynamic analyses, itwas given its own name, kinematic viscosity, n. The cgs unit ofviscosity is the centipoise (cP). The SI unit of viscosity is thePascal-s (Pa-s)
23、.Absolute viscosity is defined for a Newtonian fluid asfollows. The shear stress at any point in the fluid is proportionalto the rate of shear. The proportionality constant is called theabsolute viscosity. Viscosity is thus defined by the force, F,tomove one surface of area, A, with respect to anoth
24、er surfaceseparated by a fluid film, h, at a speed, U, through the followingrelationship:h5F/A!h/U!The value of the absolute viscosity changes greatly withtemperature, T. As the temperature increases viscosity de-creases. ASTM International has adopted the following rela-tionship between kinematic v
25、iscosity and temperature:log10log10n10.8! 5 m log10T 1 cwhere:m and c = constants for each fluid.ASTM International supplies chart paper with the ordinateproportional to log10log10(n + 0.8) and with the abscissaproportional to log10T. Thus the values of kinematic viscosityversus temperature can be p
26、lotted as a straight line on the paperallowing extrapolation of values intermediate to those that havebeen measured.Absolute viscosity is a weak function of the pressureimposed upon the fluid. However, the pressures generated inthe ball-race contact zone of a ball bearing can be on the orderof 103GP
27、a (105psi) and at these pressures significant increasesin viscosity can occur. Experiments have shown that viscosityvaries exponentially with pressure and can be expressed asfollows:h5h0exp ap!where:h0= viscosity at a pressure of one atmosphere,p = pressure, anda = pressure-viscosity coefficient.A t
28、able of values of a for some common classes of bearinglubricants can be found after the definition of pressure-viscosity coefficient included in this glossary.Recent work has shown that the viscosity changes withtemperature can also be modeled by an exponential relation-ship. Thus, viscosity at any
29、pressure and temperature can beexpressed as follows:hT, p5h0exp ap 1b1/T 1 1/T0!where:b = temperature-viscosity coefficient.3.1.3 acid number, na measure of the quality of a lubri-cant. High acid numbers (much higher than the fresh oil) are anindication of lubricant oxidation/degradation. Oils with
30、highacid numbers should not be used. Acid number is measured asmilligrams of KOH needed to neutralize one gram of oil.3.1.4 additive, nany chemical compound added to alubricant to improve or meet special needs necessary forservice (formulated lubricants). The most important additivesare antioxidants
31、, rust and corrosion inhibitors, and extremepressure (EP) and antiwear (AW) additives.3.1.5 antioxidants (oxidation inhibitors), nchemical com-pounds used to improve the oxidation stability and subsequentdeterioration of lubricants.3.1.6 boundary lubrication, na condition of lubrication inwhich the
32、friction between two surfaces in relative motion isdetermined by the roughness of the surfaces and by theproperties of the lubricant other than viscosity. Antiwear andextreme pressure additives reduce the wear of componentsoperating under this regime.3.1.7 centipoise, na unit of dynamic viscosity. T
33、he unit inthe cgs system is one centipoise (cP). The SI unit of dynamicviscosity is 1 Pa-s and equivalent to 103cP.3.1.8 centistoke, na unit of kinematic viscosity. The unitin the cgs system is one centistoke (cSt). The SI unit ofkinematic viscosity is 1 m2/s and is equivalent to 106cSt.3.1.9 compat
34、ibility, na measure of the ability of a lubri-cant to be mixed with other lubricants or bearing preservatives(fluids that form films on metal surfaces to prevent corrosionduring storage) to form a uniform mixture without causing anyresultant reaction or precipitation of material. Compatibility isals
35、o a measure of the ability of a lubricant not to cause anydetrimental effect to metal, plastic, or elastomer materials.7Annual Book of ASTM Standards, Vol 05.02.8Available from Document Automation and Production Service, Building 4/D,700 Robins Ave., Philadelphia, PA 191115094.F21610123.1.9.1 Discus
36、sionIt is recommended that any preserva-tive material be removed from bearings before lubrication.3.1.10 contamination, n(1) The presence of mostly solidforeign materials like sand, grinding powder, dust, and so forth,in a lubricant that might cause an increase in wear, torque, andnoise and result i
37、n reduced bearing life. (2) The presence offluids like water, solvents, and other oils that might causeaccelerated oxidation, washout, rusting, or crystallization ofthe additives and other phenomena that reduce a bearings life.3.1.11 corrosion, nthe gradual destruction of a metalsurface due to chemi
38、cal attack caused by polar or acidic agentslike humidity (water), compounds formed by lubricant deterio-ration, or by contaminants from the environment.3.1.12 corrosion inhibitors, ncorrosion inhibitors protectmetal surfaces against corrosion or rust by forming a protectivecoating or by deactivation
39、 of corrosive compounds formedduring the operation of a bearing.3.1.13 density, nthe mass per unit volume of a substance.The cgs unit of density (r) is 1 g/cm3, and the SI unit of densityis 1 kg/m3. Density depends on the chemical composition andin itself is no criterion of quality. It is a weak fun
40、ction oftemperature and pressure for liquids and solids.3.1.14 DN value, nthe product of the bearing bore diam-eter in millimetres multiplied by the speed in revolutions perminute (compare to nDm-value).3.1.15 dynamic viscosity, nanother name for absoluteviscosity.3.1.16 elastohydrodynamic theory (E
41、HD), nSee Appen-dix X2.3.1.17 EP lubricants (extreme pressure lubricants),nlubricants (oil or greases) that contain extreme pressureadditives to protect the bearings against wear and welding(scoring).3.1.18 esters, nesters are formed from the reaction ofacids and alcohols. Esters form a class of syn
42、thetic lubricants.Esters of higher alcohols with divalent fatty acids form diesterlubricants while esters of polyhydric alcohols are called thepolyol ester lubricants. These latter esters have higher viscosityand are more heat-resistant than diesters.3.1.19 evaporation loss, nlubrication fluid losse
43、s occur-ring at higher temperatures or under vacuum, or both, due toevaporation. This can lead to an increase in lubricant consump-tion and also to an alteration of the fluid properties of alubricant (especially an increase in the viscosity of blendedlubricants). The evaporation loss is expressed as
44、 a weight lossin milligrams (10-6kg) or wt %.3.1.20 fire point, nthe lowest temperature at which thevapor or a lubrication fluid ignites under specified test condi-tions and continues to burn for at least 5 s without the benefitof an outside flame. The fire point is a temperature above theflash poin
45、t. Perfluoropolyethers have no fire point.3.1.21 flash point, nthe lowest temperature of a lubrica-tion fluid at which the fluid gives off vapors that will ignitewhen a small flame is periodically passed over the liquidsurface under specified test conditions. The flash and fire pointsprovide a rough
46、 characterization of the flammable nature oflubrication fluids. Perfluoropolyethers have no flash point.3.1.22 four-ball tester, na tester used to evaluate the wearbehavior of lubricants under extreme pressure. Four steel ballsare arranged in a pyramidal shape. During the test, the threeballs compri
47、sing the base of the pyramid are stationary whilethe upper ball rotates. The lubricant sample is placed in the ballpot. The average wear scar (measured in millimetres) formedon the stationary balls is reported.3.1.23 fretting corrosion, na special type of wear pro-duced on materials in intimate cont
48、act that are subjected to thecombined action of oscillatory motions of small amplitudesand high frequencies. Fretting corrosion appears similar toatmospheric corrosion (rust) as a reddish-brown layer on steelsurfaces.3.1.24 interfacial tension, nwhen two immiscible liquidsare in contact, their inter
49、face has many characteristics incommon with a gas-liquid surface. This interface possessesinterfacial free energy because of the unbalanced attractiveforces exerted on the molecules at the interface by themolecules within the separate phases. This free energy is calledthe interfacial tension.3.1.25 instrument bearings, nall bearings whose outerdiameter is 30 mm or less, as defined by The American BearingManufacturers Association (ABMA).3.1.26 kinematic viscosity, nthe ratio of absolute viscosityto fluid density. This ratio arises frequently in lubri
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