Core Roughness Depth (Rk)

When working with surface profilometers, core roughness depth (Rk) is a hybrid parameter that describes the main bearing area of the surface. Core roughness depth provides an indication of the long term running surface that influences bearing performance after the initial high points or peaks have been worn away. The core roughness depth falls between the reduced peak height (Rpk) and the reduced valley depth (Rvk). Reduced peak height is a measure of the surface profile that is worn away during the initial run-in period. Reduced valley depth is the region of the surface profile that always retains lubricant.