A study of the mechanisms of abrasive wear for ductile metals under wet and dry three-body conditions

A simple predictive model was developed for three-body abrasive wear of ductile metals assuming that mass loss resulted from repeated indentation from the corners and asperities of angular particles rolling across the surface of the wear specimen. The model assumed that material removal occurred through a ratcheting/fatigue mechanism at a rate given by a modified Coffin-Manson equation. The validity of the model was examined for the three-body wear of a mild steel and stainless steel under dry and wet conditions with silicon carbide particles (180 and 1000 Grit) as the abrasive. Wear tests for both dry and wet conditions were carried out on the same tester, a commercial lapping and polishing machine. Under most conditions the model proved to be unsatisfactory, as it does not take into account wear through sliding and cutting by the particles. Examination of wear surfaces suggested that individual particles traversed the wear surface in a mixed slide (scratch)-roll manner. Under most of the test conditions examined, sliding/cutting was the dominant metal removal mechanism, although wear by indentation was generally not insignificant. Wet conditions, for tests with the larger (180 Grit) particles, further promoted a sliding and cutting mode of wear. However, for tests with smaller (1000 Grit) particles the hydrodynamic lift provided by the lubricant may in some circumstances facilitate rolling of the particles and an indentation wear mechanism.