EXPLANATION
This test method is used to evaluate the property of lubricating greases to protect oscillating bearings from fretting wear. It is used for specification purposes, and differentiates between greases allowing low, medium, and high amounts of fretting wear under the prescribed test conditions. Test results do not necessarily correlate with results from other types of service.
TEST SUMMARY
The tester is operated with two ball thrust bearings, lubricated with the test grease. It is oscillated through an arc of 0.21 rad (12°) at a frequency of 30 Hz (1800 cpm) under a load of 2450 N (550 lbf) for 22 h at room temperature. Fretting wear is determined by measuring the mass loss of the bearing races.
TEST PRECISION
Where X is the average mean mass losses of two tests in milligrams.
This procedure has no bias.