Mechanism of Transient Phenomena of Wear in Repeated Friction

Abstract

In repeated friction, the wear rate varies with increasing the sliding length, i.e. it is mostly very high at the beginning, but later decreases to a lower constant value. Mechanism of these transient phenomena of wear is discussed in this paper. Special wear machine, with which tests can be carried out in virgin and repeated friction, is used for rubbing of steel and copper on steel in dry and lubricated states. Effects of surface roughness and wear dust accumulated on rubbing surface are examined in several methods. Wear processes of undeformed and deformed surface layers by frictional force are compared. Then, it is concluded that the transient phenomena of wear are mainly affected by accumulation of wear dust on rubbing surface, not by formation of deformed and hard surface layer, or variation of surface roughness.