Study of Wear Evolution for a Hydraulic Oil Using a Four Ball Tester

Abstract

Time is crucial for the wear of materials. Time of an experiment must be long enough to obtain an observable wear but no so long to make the experiments expensive. For determining anti-wear properties of the hydraulic oils the standard EN ISO 20623:2004 indicates 1 hour under an applied load of 150 N. The Romanian standard STAS 8618_1979 does not specify anything about this. The present paper had analysed the wear evolution for a hydraulic oil, using the four ball tester, in order to determine the optimum duration for such a test. Supplementary, the relation between mean scar diameter and the removed volumes of ball material is analysed.