1、Designation: F2161 10Standard Guide forInstrument and Precision Bearing LubricantsPart 1 Oils1This standard is issued under the fixed designation F2161; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A n
2、umber in parentheses indicates the year of last reapproval. Asuperscript epsilon () 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 gui
3、de 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 performed
4、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, thatis,
5、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 for
6、th. 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 bearings
7、. 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 cen
8、tered 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 replenishment
9、. 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 ap
10、plications, 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 Anoth
11、er 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 for c
12、omparing 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 res
13、ults 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 Documents
14、2.1 ASTM Standards:4D92 Test Method for Flash and Fire Points by ClevelandOpen Cup TesterD97 Test Method for Pour Point of Petroleum ProductsD445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D974 Test Method for Acid and Base Number by C
15、olor-Indicator TitrationD972 Test Method for Evaporation Loss of LubricatingGreases and Oils1This guide is under the jurisdiction of ASTM Committee F34 on RollingElement Bearings and is the direct responsibility of Subcommittee F34.02 onTribology and was developed by DoD Instrument Bearing Working G
16、roup (IBWG)former F34.Current edition approved Jan. 1, 2010. Published February 2010 originallyapproved in 2001. Last previous edition approved in 2001 as F216101. DOI:10.1520/F2161-10.2Product Standard, Lubricants , available from The Barden Corp., Danbury,CT.3NASA Lubricant Handbook for the Space
17、Industry, Ernest L. McMurtrey ,NASA Technical Memorandum TM-86556, George C. Marshall Space Flight Center,National Aeronautics and Space Administration, December 1985.4For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual
18、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.D1331 Test Methods for Surface and Interfacial Tension ofSolutions of Surface-A
19、ctive AgentsD2270 Practice for Calculating Viscosity Index from Kine-matic Viscosity at 40 and 100CD4172 Test Method for Wear Preventive Characteristics ofLubricating Fluid (Four-Ball Method)2.2 Government Documents5:MIL-DTL-53131 Lubricating Oil, Precision Rolling Ele-ment Bearing, Plolyalphaolefin
20、 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-81846 Lubricating Oil, Instrume
21、nt, 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).The ABEC establishes bearing to
22、lerance 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 losses in a ball bearing are v
23、erystrong 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).Absolute viscosity is defined
24、 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 another surfaceseparated by a fluid
25、 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 viscosity and temperature:log10
26、log10n10.8! 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 plotted as a straight line on t
27、he 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 103GPa (105psi) and at these pressu
28、res 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 table of values of a for some c
29、ommon 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 pressure and temperature can b
30、eexpressed 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 highacid numbers should not be
31、 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, rust and corrosion inhibitor
32、s, 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 friction between two surfaces
33、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. The unit inthe cgs system is on
34、e 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 compatibility, na measure of the abi
35、lity 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 isalso a measure of the ability of
36、a lubricant not to cause anydetrimental effect to metal, plastic, or elastomer materials.5Available from Document Automation and Production Service, Building 4/D,700 Robins Ave., Philadelphia, PA 191115094.F2161 1023.1.9.1 DiscussionIt is recommended that any preserva-tive material be removed from b
37、earings 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 in reduced bearing life. (2) The presence offluids like water, solvents,
38、 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 chemical attack caused by polar or acidic agentslike humidity (water), compo
39、unds 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 of corrosive compounds formedduring the operation of a bearing.3.1.13
40、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 function oftemperature and pressure for liquids and solids.3.1.14 DN value
41、, 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 (EHD), nSee Appen-dix X1.3.1.17 EP lubricants (extreme pressure lubricant
42、s),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 synthetic lubricants.Esters of higher alcohols with divalent fatty acids f
43、orm 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 losses occur-ring at higher temperatures or under vacuum, or both, due toeva
44、poration. 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 a weight lossin milligrams (10-6kg) or wt %.3.1.20 fire point, nthe lo
45、west 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 point. Perfluoropolyethers have no fire point.3.1.21 flash point, nthe lowe
46、st 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 characterization of the flammable nature oflubrication fluids. Perfluo
47、ropolyethers 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 comprising the base of the pyramid are stationary whilethe upper ball rotates
48、. 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 contact that are subjected to thecombined action of oscillatory motions of
49、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 interface 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, n
