Effects of real contact area and topographical features of wear surfaces on abrasive wear of metals

The aim of this study is to clarify various cross-sectional shapes and areas of wear grooves and ridges which are formed under multi-point contacts and to study the effect of the real contact area on the friction and wear properties in the two-body abrasive wear of metals. Two kinds of test were performed: (1) the scratching test on an actual abrasive paper under two short sliding distances (less than 1 mm or 5 mm), and (2) the friction and wear test under a long sliding distance (about 65 mm). The effects of the real contact area and surface topographical features of the wear surface of the pin on the friction and wear properties of abrasive wear are investigated systematically, and the friction and wear mechanisms are discussed. The following main results were obtained. (1) The mean area of the real contact point is affected by the existence of the embedded abrasive grains and the surface layer which is harder than the bulk material of the pin. (2) The mean cross-sectional area of the grooves on the worn surface of the pin, which is calculated from the profile curve measured perpendicular to the sliding direction, is a factor that has a direct effect upon the specific wear rate of a pin and that measured parallel to the sliding direction is the factor which affects the friction coefficient. (3) The specific wear rate for lead pins is approximately proportional to the real contact area for abrasive wear.