EXTREME PRESSURE PROPERTIES OF LUBRICATING FLUIDS: ASTM D2783
EXPLANATION
This test method is used for specification purposes, differentiates between lubricating fluids having low, medium, and high levels of extreme pressure properties. Two determinations are made: load-wear index, and weld point by means of four-ball extreme pressure tester.
TEST SUMMARY
The tester is operated with one steel ball under load rotating against three steel balls held stationary in the form of a cradle. Test lubricant covers the lower three balls. The rotating speed is 1760 +/- 40 r/min. The machine and the lubricant are brought to 65 - 95° F and then a series of tests of 10-s duration are made at increasing loads until welding occurs. Ten tests are made below the welding point.
TEST PRECISION
This test method has a repeatability of 17 and a reproducibility of 44 % of the mean value for load wear index, and both repeatability and reproducibility of more than one increment loading for weld point measurement.
The bias of this test method is not known.
