On heat generation in rolling contacts under boundary and mixed lubrication

This paper reports on experiments and theoretical analyses of heat generati on and scuffing failure in rolling contacts. The experiments were conducted with dry contacts, and the theoretical analyses were carried out using a d eterministic thermal contact model. The research reveals that heat generate d by asperity plastic deformation in the direction normal to the contact ca n be significant in high-lend, high-speed contacts under boundary and mixed lubrication conditions. Under near rolling conditions, heat generated by t he plastic deformation largely dominates that by the friction and is the ma in source leading to contact scuffing. This heat generation is shown to be significant compared to frictional heating even at relatively large slide-t o-roll ratios. Parametric studies show that the ratio of asperity-plastic-d eformation healing to frictional heating is sensitive to slide-to-roll rati o, hardness and surface finish but insensitive to contact load, rolling vel ocity and fluid/asperity load sharing.