The Transition Between Mild and Severe Wear for Boundary-Lubricated Steels

Abstract

The wear of AISI-4340 steel under boundary lubrication has been measured in reciprocating sliding. As the hardness of martensitic specimens is reduced from 700 Hv to 250 Hv the wear passes through a transition from “mild” to “severe” wear. A two-component wear model, associating the wear mechanisms with sub-surface and surface plasticity controlled modes of asperity deformation, has been quantitatively fitted to the experimental data. Good agreement is found between the values of constants in the model obtained in this way, and other theoretical and experimental data in the literature. The model can also account for the results of increasing the applied load, by allowing for the effects of increased friction and plastic collapse and removal of the most severely deformed asperities.