ASTM D4425 – Oil Separation from Lubricating Greases by Centrifuging (Koppers Method)
Lubricating greases in flexible shaft couplings, universal joints and roller element thrust bearings may experience large, prolonged centrifugal forces. This may cause the oil to separate from the thickener, potentially resulting in reduced lubrication, overheating of system components and system failure. This test determines the amount of oil that separates from a grease under a high centrifugal force.
The grease is weighed into centrifuge tubes, and centrifuged in a high speed centrifuge for the test time. The separated oil is drained, measured and the percent separation is reported.
Specify test interval: 6 hours; 12 hours; 24 hours; 48 hours; 96 hours.