Study on the Scoring Resistance of Lubricating Oil in Four Ball Test : 3rd Report, Effects of Bulk Oil Temperature and Sliding Velocity in the Test Method according to JIS

Abstract

In this paper, effects of bulk oil temperature and sliding velocity on the scoring phenomena of non-EP mineral oils were examined by a Shell type Four Ball Machine under the conditions that new steel balls were used for each load step and the machine was operated in 60 seconds after loading. The results obtained are summarized as follows : (1) Lubrication state of contact surface at last non-seizure load and the process of scoring at initial seizure load are affected by bulk oil temperature and in higher sliding velocity range, it is difficult to evaluate the scoring resistance of boundary lubricating film. Therefore, in the evaluation of scoring resistance of lubricating oil, attention must be paid to these points. (2) There is a correlation between the scoring resistance of boundary lubricating film and the maximum contact surface temperature except in the region of lower sliding velocity.