Roughness and Wear during Elstohydrodynamic Partial Lubrication.

It is shown that for the wear of a friction couple with a pointwise contact surface during pure sliding in the elastohydrodynamic partial lubrication region there exists an optimal roughness, namely R//a congruent 0. 045 mu m. A reduction of the roughness to R//a congruent 0. 015 mu m causes an approximately 40-fold increase in the wear volume. This result indicates that the film thickness/surface roughness ratio should only be used within certain limits to describe the lubrication state in the elastohydrodynamic partial lubrication region.