The MFT5000 is a versatile multi-function mechanical property tester capable of simulating a vast number of tribology and wear tests on same platform. This application note shows how the MFT5000 can be used to study grease, oil for EP and wear tests using its 4 Ball Module. 4 Ball module can be used for several standard tests such as ASTM D2266, D4172, ASTM D2596, ASTM D2783, BS EN ISO 20623, BS ISO 26422, CEC L-45-A-99, DIN 51 350, IP 239. The module is used to characterize lubrication properties of oils and greases under nominal and extreme pressure conditions.
A steel ball is rotated under load against three stationary balls in presence of a lubricant. The rotation speed (upto 5000 rpm), loading rate and applied load ( up to 10,000N) and temperature (up to 150 C) are set according to the standard being followed. The load can be applied in a linearly increasing manner or the test can be ran at a constant load.
Wear Test – This test is used to evaluate lubrication performance of grease or oil. The test is carried out at relatively mild test conditions e.g. 392N at 75C at 1200 rpm for 1 hour. Tests with higher loads, and longer durations can also be designed. The performance of the lubricant is evaluated by measuring and comparing the wear diameter of the balls after the test. Diameter of wear scar on each of the three lower balls is measured at two locations 90° to each other. The average of six measurements is reported as wear diameter for the 4 ball test.
Figure shows the 3D Image of the wear track on one of the lower sample after running a 4 Ball wear test for 1 hour at 1200rpm and 392N.