Influence of incidence angle on wear induced by sliding impacts

Experiments are performed to analyze wear generated by low load sliding impacts on ferrite steel and stainless steel samples. Low load impacts are defined by a normal force such that the apparent contact pressure remains below the yield strength of the material. Nevertheless, concentration of pressure at the top of asperities may generate local plastic deformation. Beyond a running-in period, repetitive oblique impacts cause wear. A high frequency acquisition of dynamical contact forces allows an accurate characterization of impacts (rate, duration, strength) and forces (tangential and normal components and their ratio). These data are correlated with wear volume. The effect of the incidence angle is discussed. The results obtained confirm the combined effects of incidence angle and force ratio on the effective wear of impacts. An erosive wear model is introduced whose results explain all experimental observations. The normalized shear energy seems to be relevant in accounting for the measured evolution of wear with impacts orientation.