Wear of plain bearing materials with particular reference to role of soft phases

Abstract

An important criterion that determines the suitability of a material to be used in a lubricated journal plain bearing is its wear performance under conditions of boundary lubrication. In this investigation a pin-on-ring wear machine has been designed and constructed to study the wear characteristics of plain bearing materials. Tests were carried out under both dry and boundary lubricated conditions. The results provide a fundamental understanding of the wear characteristics of plain bearing materials and show how lubrication modifies the surface conditions and wear processes. The presence of a soft phase within the microstructure of the plain bearing controls running-in wear under dry sliding conditions by the generation of smeared low shear strength metallic films. Under lubricated conditions the generation of such films is less essential and hard bearing materials exhibit acceptable running-in characteristics. The use of hard plain bearing materials, however, does result in greater counter face wear. Results obtained from these wear tests are comparable to those in the published literature and demonstrate the feasibility of using relatively simple techniques to provide an understanding of the wear characteristics of plain bearing materials. Such test techniques may therefore be used in the initial stages of plain bearing material development to provide a cost effective alternative to expensive engine tests.

MST/1377