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 (coded as C G iron) in dry sliding against 40Cr steel were investigated with a 3 D surface profilometer. The topographical parameters have been analyzed by taking into account the thermal effect during the friction process. As the results, three kinds of typical topographical features have been observed for the worn surfaces of C G iron with various P content. Namely, C G iron with 0.05% P, 1.30% P, and 0.70% P show worn surfaces characterized by groove ridge, peak pits and their combined topography. The C G iron specimen with peak pits type worn surface topography showes the lowest wear rate and highest friction coefficient, while that with groove ridge type worn surface topography shows the highest wear rate and lowest friction coefficient. The groove ridge type worn surface has a relatively large value of surface height deviation and void volume ratio and negative large value of skewness, which is contrary to the peak pits topography.