ASTM D4425 for oil separation from lubricating grease
ASTM D4425 standard test method for oil separation from lubricating grease by centrifuging (Koppers Method)
4. Summary of Test Method
4.1 Pairs of centrifuge tubes are charged with grease samples and are placed in the centrifuge. The grease samples are subjected to a centrifugal force equivalent to a G value of 36000, at 50°C more or less 1°C, for specific periods of time. The resistance of the grease to separate the oil is then defined as a ratio of the percent of oil separated to the total number of hours of testing.
5. Significance and Use
5.1 This test method is useful in evaluating the degree to which a grease would separate into fluid and solid components when subjected to high centrifugal forces. Flexible shaft couplings, universal joints, and rolling element thrust bearings are examples of machinery which subject lubricating greases to large and prolonged centrifugal forces. This test method has been found to give results that correlate well with results from actual service. The test method may be run at other conditions with agreement between parties but the precision noted in this test method will no longer apply.
