3-D Topographical characteristics of dry sliding surface of compacted graphite irons coupled with chromium steel disk

The topographical characteristics of the worn surfaces of compacted graphite iron in dry sliding against 40Cr steel were investigated with a 3-D surface profilometer. The topographical parameters were analyzed by taking account of the thermal effect during the friction process. Three types of typical topographical features observed on the worn surfaces of the iron with various P contents including 0.05% P, 1.30% P, and 0.70% P were characterized by groove-ridge, peak-pits and the combined topography respectively. The peak-pits type has the lowest wear rate and highest friction coefficient, while the groove-ridge type has the highest wear rate and lowest friction coefficient. The groove-ridge type has the largest surface height deviation, largest void volume ratio and high negative value of skewness, while the peak-pits type has the smallest surface height deviation, smallest void volume ratio and high positive value of skewness.