ASTM D3527 Test Method for Life Performance of Automotive Wheel Bearing Grease
1. Scope
1.1 This test method covers a laboratory procedure for evaluating the high-temperature life performance of wheel bearing greases when tested under prescribed conditions.
NOTE 1 - Changes to this test method in the 1985 revision increased test severity. Results will not be comparable with data from earlier procedures.
1.2 The values stated in SI units, except apparatus dimensions, are to be regarded as the standard. Apparatus dimensions in inches are to be regarded as the standard.
1.3 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 determine the applicability of regulatory limitations prior to use. For speciFIc hazard statements, see 8.1-8.4.
2. Referenced Documents
2.1 AFBMA Standard:
AFBMA Standard 19, 1974 (ANSI B. 3.19-1975)
3. Terminology
3.1 DeFInitions:
3.1.1 lubricant, n - any material interposed between two surfaces that reduces the friction or wear between them.
3.1.2 lubricating grease, n - a semi-fluid to solid product of a dispersion of a thickener in a liquid lubricant.
3.1.2.1 Discussion - The dispersion of the thickener forms a two-phase system and immobilizes the liquid lubricant by surface tension and other physical forces. Other ingredients are commonly included to impart special properties.
3.1.3 thickener, n - in lubricating grease, a substance composed of finely-divided particles dispersed in a liquid lubricant to form the product's structure.
3.1.3.1 Discussion - The solid thickener can be fibers (such as various metallic soaps) or plates or spheres (such as certain non-soap thickeners) which are insoluble or, at the most, only very slightly soluble in the liquid lubricant. The general requirements are that the solid particles be extremely small, uniformly dispersed, and capable of forming a relatively stable, gel-like structure with the liquid lubricant.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 automotive wheel bearing grease, n - a lubricating grease specifically formulated to lubricate automotive wheel bearings at relatively high grease temperatures and bearing speeds.
3.2.2 grease life, n - of wheel bearing grease, amount of time operated under prescribed conditions of load, speed, and temperature until preset torque limit is exceeded.
3.2.2.1 Discussion - The off-time, which is part of the 20 h and 4 h off-cycle, is not recorded and is not included as part of grease life.
