On the running-in nature of metallic tribo-components: A review

Abstract Running-in plays an important role in the steady-state performance of mechanical elements. It is a transient process involving a complex interaction between friction, lubrication, asperities, plastic deformation, and wear in an intertwined fashion. The running-in process involves the evolution of the key tribological parameters such as surface roughness, surface pattern, friction coefficient, and wear rate until the steady-state prevails. Importantly, the steady-state behavior of a tribo-component is dependent upon the operating conditions during the running-in process. This paper provides a comprehensive review of the literature on this subject encompassing both experimental and analytical development to date.