The effect of cast iron graphites on friction and wear performance I: Graphite film formation on grey cast iron surfaces

Abstract

Cast iron is assessed as a self-lubricating metal-base composite material. The formation of cast iron graphite films and the effective surface treatment of grey cast iron are discussed. It was found that the friction and wear behaviour of cast iron are influenced by the formation of a graphite surface layer. When cast iron surfaces are etched with Nital, they are found to be covered with a graphite film during the sliding friction process. This contributes to the protection of metallic contact points. The formation of graphite films during testing is assumed to be due to the non-elastic deformation of surface graphite. The effects of applied load, sliding velocity and lubricant are also discussed. The coefficient of friction increases with applied load and sliding velocity, and therefore lubrication becomes more important. These phenomena are discussed in terms of the formation of graphite films during the friction process. © 1981.