Comparison of rolling contact fatigue life between elastohydrodynamic lubricated point contacts pre and post running-in treatment

摘要

Rolling contact micropitting fatigue life is affected by stress fields in shallow subsurface. It is well known that there is a significant dependence, of stress distribution in subsurface, on the surface microstructures. Therefore rolling contact micropitting fatigue lives can be enhanced through modifying surface topography. In this study, running-in method was employed as the method to alter surface microstructures to explore the effect of various morphological characteristics on micropitting fatigue lives. Firstly, various rough surfaces were formed by applying experimental running in processes on a series of ball-on-disc pairs. Meanwhile, the evolutions of topography during the running-in processes were recorded. Secondly, rolling contact fatigue lives of these rough surfaces under elastohydrodynamic lubricated condition were calculated and compared based on Zaretsky's fatigue model combined with elastic contact mechanics. The results have indicated that a running-in process has significantly positive effect on prolonging micropitting fatigue lives. Theoretical analysis of the relationship between topographical parameters and micropitting fatigue lives to ascertain optimum morphological characteristics which are beneficial in reducing micropitting fatigue failures is the key originality of this work. This work provides guidelines on surface morphology for achieving maximum pitting fatigue life for interacting systems. In turn enhanced durability of the systems will lead to significant cost savings.