Standard method for measuremet of extreme-pressure properties of lubricating grease (four-ball method)
This method covers the determination of the load-carrying properties of lubricating greases. Two determinations are made: load-wear index (formely called mean-hertz load), and weld point, by means of the four-ball extreme-pressure (EP) tester. The tester is operated with one steel ball under load rotating against three steel balls held stationary in the form of a cradle. The rotating speed is 1770 +- 60 rpm. Lubricating greases are brought to 27 +- 8/sup 0/C (80 +- 15/sup 0/F) and then subjected to a series of tests of 10-s duration at increasing loads until welding occurs. This method, used for specification purposes, differentiates between lubricating greases having low, medium, and high level of extreme-pressure properties. The results do not necessarily correlate with results from service. It is noted that lubricating greases that have as their fluid component a silicone, halogenated silicone, or a mixture comprising silicone fluid and petroleum oil, are not applicable to this method of test.
- OSTI ID:
- 6513061
- Journal Information:
- Annu. Book ASTM Stand.; (United States), Vol. 24; Other Information: ANSI/ASTM-D--2596-69
- Country of Publication:
- United States
- Language:
- English
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