Effect of surface topography with different groove angles on tribological behavior of the wheel/rail contact using alternative machine

The objective of this study was to investigate the influence of the surface topography on the tribological behavior of the wheel/rail contact. Four different groove orientations forming the surface topographies—smooth surface, 0°, 45° and 90°—were manufactured by grinding and compared. All friction tests with different surface topographies were conducted using an alternative tribometer simulating the pure sliding process in the wheel-rail contact. The Hertzian pressure was maintained at 1,000 MPa with two levels of sliding velocity (20 mm/s and 80 mm/s). This study resulted in five main findings.

First, the initial surface topographies seemed to have a significant effect on the friction coefficient independently of the speed. Second, the increase of the sliding velocity would decrease the friction coefficient. Third, especially when accompanied with a high sliding velocity, an initial rough surface would have a significant effect on the wear of the wheel. Fourth, the highest wear values were observed at groove orientations of 45° when accompanied with a high sliding velocity. Finally, the break-in duration seemed to depend on the initial surface topographies of the rail and the sliding velocity.