Frictional response of precision finished surfaces in pure sliding

The functional performance of a component is closely tied to the geometric properties of its surface, which is an outcome of the finishing process used to make the component. This paper investigates the role of three-dimensional (3-D) surface topographic features of four precision finished surfaces (Ground, Hard Turned, Honed, and Isotropic) commonly used in the bearing industry on their frictional response. Experiments are conducted to investigate the effect of surface type, sliding speed, and normal contact load on the coefficient of kinetic friction under point contact. The effect of lay is also analyzed for the strongly anisotropic ground surface. Based on a detailed 3-D surface characterization, it is shown that the amplitude parameter Sq (rms deviation of surface), and spatial parameters Sds (density of summits) and Std (texture direction) play an important role in determining the frictional behavior of the surfaces studied. An empirical model for the coefficient of kinetic friction as a function of these parameters is proposed.