Investigation on topography of dry sliding surface of compacted graphite cast iron

By using 3-D surface topographical measurement, the topographical features of dry sliding surface of compact graphite cast irons were investigated. The surfaces are characterized by pit-peak like, groove-ridge and combined topography. For the pit-peak surface, the surface height distribution range is very small and its surface height has asymmetric distribution. For the groove-ridge surface, the sliding surface height has a very large range in the direction perpendicular to the sliding surface and the surface height distribution is also asymmetric. For the combined topographical surface, the surface height distribution is symmetric and has a medium range. It was suggested that surface height distribution range and void volume ratio are the two most important factors which influence the conductivity of frictional heat being transferred to the far end of the contacting zones, thereby, the surface with pit-peak topography presents the highest friction coefficient and wear resistance, and the surface with groove-ridge topography presents the lowest ones.