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    ASTM F2661 - 07(2015)

    Standard Test Method for Determining the Tribological Behavior and the Relative Lifetime of a Fluid Lubricant using the Spiral Orbit Tribometer

    Active Standard ASTM F2661 | Developed by Subcommittee: F34.02

    Book of Standards Volume: 01.08


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    Significance and Use

    5.1 Relevance of the Spiral Orbit Tribometer (SOT)—The SOT was designed to evaluate the relative degradation rates of liquid lubricants in a contact environment similar to that in an angular contact bearing operating in the boundary lubrication regime. It functions as a screening device to quickly select the lubricants, evaluate the ability of various components of a lubricant (base oil, thickener, or additive) to lubricate a contact in rolling, pivoting, and sliding conditions simultaneously, and study their chemical decomposition if necessary. The SOT provides a means to study the tribological behavior of oils and greases during operation, while they undergo changes as a function of typical parameters encountered in the lubrication field (temperature, environment, materials used, load applied, and speed). Test conclusion is defined to be when a friction coefficient limit (typically an increase of 0.1 above the steady state value) is surpassed. Normalized lubricant lifetime is then defined as the number of orbits completed divided by the initial amount of lubricant used (in μg). The SOT was initially developed to evaluate lubricants for space applications, but is also relevant for conventional environments. Some results in vacuum are presented (Fig. 1). At this time, no data for tests in ambient conditions have been published (see Fig. 2). The user of this test method should determine to their own satisfaction whether results of this test procedure correlate with field performance or other bench test procedures.

    Bazinet, D.G., Espinosa, M.A., Loewenthal, S.H., Gschwender, L., Jones, W.R., Jr., Predmore, R.E., “Life of Scanner Bearings with Four Space Liquid Lubricants”, Proc. 37th Aerospace Mech. Symp., Johnson Space Center, May 19-21, 2004

    1. Scope

    1.1 This test method covers the quantitative determination of the friction coefficient and the lifetime of oils and greases, when tested on a standard specimen under specified conditions of preparation, speed, Hertzian stress, materials, temperature, and atmosphere, by means of the Spiral Orbit Tribometer (SOT). This test method is intended primarily as an evaluation of the lifetimes of fluid lubricants under vacuum and ambient conditions.

    1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    D1193 Specification for Reagent Water

    F22 Test Method for Hydrophobic Surface Films by the Water-Break Test

    F2215 Specification for Balls, Bearings, Ferrous and Nonferrous for Use in Bearings, Valves, and Bearing Applications

    G115 Guide for Measuring and Reporting Friction Coefficients

    Anti Friction Bearing Manufacturers Association Standards

    ANSI ABMA ISO 3290 (AFBMA Standard 10 Balls)


    ICS Code

    ICS Number Code 75.100 (Lubricants, industrial oils and related products)

    UNSPSC Code

    UNSPSC Code 15120000(Lubricants and oils and greases and anti corrosives)


    Referencing This Standard

    DOI: 10.1520/F2661-07R15

    ASTM International is a member of CrossRef.

    Citation Format

    ASTM F2661-07(2015), Standard Test Method for Determining the Tribological Behavior and the Relative Lifetime of a Fluid Lubricant using the Spiral Orbit Tribometer, ASTM International, West Conshohocken, PA, 2015, www.astm.org

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