Cracks and degradation layers in large flat-on-flat fretting contact with steels and cast iron

Abstract

Fretting may deteriorate contacts in terms of wear and cracking. Fretting-induced material degradation and frictional behaviour was studied experimentally in a large flat-on-flat fretting contact with a moderate nominal normal pressure and in different sliding conditions. The materials studied were cast iron, structural steel, and quenched and tempered steel. The results for all materials revealed a severely deformed microstructure, a tribologically transformed structure with high hardness, an oxidized third body layer and cracking. The initial peak in the coefficient of friction followed by stabilization occurred in all material pairs in gross sliding conditions. With low utilization of friction, only a limited amount of damage occurred. The results for each of these materials were compared.