EVALUATION OF THE PLASTICITY INDEX AS A SCUFFING CRITERION

The plasticity index has often been invoked as an indicator of the mos t likely condition for scuffing of metals. The particular condition fo r initiating scuffing was thought to be 2% plastic strain in contactin g asperities, which would lead to adhesion between asperities. Experim ents were done to validate the hypothesis using low alloy steels and s tainless steel, lubricated with plain mineral oil and mineral oil cont aining 1% stearic acid, in slow single-pass sliding and in repeat pass sliding. Some experiments showed an influence of asperity slope on sc uffing load as suggested by the plasticity index. Most experiments sho wed no such influence. All experiments showed that a great amount of p lastic flow occurred before scuffing occurred.