Paper 1: Metallurgical Aspects of Wear

Progress in wear prevention can be aided by a clearer understanding of the failure mechanisms and their controlling factors. Metallurgical aspects, which affect the choice of materials, and metallographic changes brought about by service conditions can influence the basic mechanisms. Topography and structure can affect the frictional and wear behaviour of materials, so a careful study of the surfaces involved and the structure of surface layers is necessary to assess changes due to relative motion, lubricant and environmental effects. Various types of wear such as scuffing, abrasion, fretting, and pitting are described; the mechanisms of failure and the metallurgical factors involved are discussed and illustrated. Metallurgical methods of reducing wear by surface treatments such as carburizing, nitriding, and hard facing are described. Methods of controlling wear by surface treatments which lubricate such as phosphating, soft nitriding and solid film are discussed.