Dry sliding wear of Ni alloyed austempered ductile iron

Measurements of dry sliding wear are presented for ductile irons with composition Fe-3.56C-2.67Si- 0.25Mo-0.5Cu and Ni contents of 0.8 and 1.5 in wt.% with applied loads of 50, 100 and 150 N for austempering temperatures of 270, 320, and 370 ℃ after austenitizing at 870 ℃ for 120 min. The mechanical property measurements show that the grades of the ASTM 897M： 1990 Standard can be satisfied for the selected austempering conditions. The results show that wear resistance is independent of austempedng temperature with an applied load of 50 N, but there is a strong dependence at higher austempering temperatures with applied loads of 100 and 150 N. Observations indicate that wear is due to subsurface fatigue with cracks nucleated at deformed graphite nodules.