The Effect of Surface Irregularities on the Tribological Behavior of Steel Rollers Under Rolling-Sliding Contact

Abstract

Experiments were conducted utilizing a gear-cam adapter to simulate line-contact lubrication and wear. Roller specimens with various asperity heights and roughness patterns were riding on the roller plates and sliding over the two lands of the lower specimen. The experimental results reveal that the roughness pattern and the asperity height are of importance in determining the friction coefficient, whereas asperity height is more related to the wear rate. The temperature rise of the lubricant seems to be seldom affected by the foregoing factors, but is governed by the combined effect of applied load and driver’s rotational speed. Surface roughness with a transversely oriented pattern, irrespective of the asperity height, normally generates a smaller friction coefficient and a relatively larger wear rate compared to the other two roughness patterns. Rollers having a smooth surface (0.2 μm) do not always lead to the smallest friction, but usually produce the minimum wear rate. The operating conditions, including the increase in applied load, and the reduction of the driver’s rotational speed, along with the increase of asperity height, form the controlling factors of increasing wear rate.