The effect of surface topography on dry fretting in the gross slip regime

This paper describes the tribological influence of surface topography on friction and wear under dry fretting gross slip regime in a point contact. Experiments were made using ball-on-disc tribotester in oscillatory motion. 100Cr6 sphere co-acted with a disc made of 42CrMo4 steel. During tests, the friction force was monitored as a function of time. Wear of discs and balls was measured after the tests using white light interferometer. Disc surfaces were prepared by various techniques, including milling, vapour blasting, polishing, lapping and grinding. Initial surface roughness height of discs, determined by the Sq parameter was in the range: 0.01-9 μm. During tests, normal load was kept constant at 45 N within the contact with frequency of 20 Hz. Tests were carried out with different displacement amplitudes: 0.02, 0.05 and 0.075 mm. It was found that initial surface roughness height had a significant influence on friction and wear.