Proposal of invariant precursors for boundary lubricated scuffing

One of the fundamental problems in tribology is the difficulty in predicting final performance and, in particular, the longevity of lubricated or not frictional components. In most cases of the hydrodynamic or elastohydrodynamic lubricated parts, if the load is too high or the motion of the rubbing elements is too slow, boundary lubrication occurs and predicting the performance of the bodies may become complicated due to the scuffing that can appear. The authors of this paper aimed to shear their knowledge and contribute to better understanding of this transitional phase dealing frequently with catastrophic wear. An analysis of various factors (residual stresses, surface free energy and surface morphology) that contribute to and allow for the identification of conditions that lead to the starting phase of the scuffing process will be presented in this paper. The double-blind strategy of experiments was implemented to achieve a higher standard of scientific rigour thus leading to a new concept of the scuffing invariant precursors.