The effect of oxide particles supplied at the interface before sliding on the severe-mild wear transition

The transition in behaviour from a severe running-in to a steady mild wear was examined by the supply of oxide particles into the interface before sliding. The specimen material was a carbon steel (S45C). Experiments were carried out under a normal load of 39 N, a sliding velocity of 86.4 mm s−1 and a sliding distance of up to 1000 m in air. The surface roughness of the specimen and the particle size of the oxide supplied were varied. When the particles were supplied, the severe running-in wear volume was reduced by a factor of ten. When the surface roughness was 20 μm Rmax the severe wear volume was a minimum: less than one-sixtieth of that without particles. The rough surface could retain the particles in the grooves, which caused a compacted oxide layer to form quickly. Oxide particles 1 μm in diameter were the most effective in reducing the severe wear volume. The mild wear rate was also affected by both the surface roughness and the particle size, and was a minimum at a surface roughness of 20μm Rmax and on supplying the smallest particles (0.3μm). It was confirmed that the transition occurred when a compacted oxide layer was formed and it had sufficient load-carrying capacity.