DRY SLIDING WEAR OF AUSTEMPERED DUCTILE IRON

A series of austempered ductile iron samples were prepared at austempe ring temperatures of 370, 340, 300, and 270 degrees C. Their sliding d ry wear behaviour was studied under applied loads of 110, 300, 500 and 800 N. The results obtained showed that the wear resistance is indepe ndent of austempering temperature with low applied loads, but shows a strong dependence on austempering temperature at high applied loads (5 00 and 880 N), reaching a maximum value at a temperature of 340 degree s C. Scanning electron microscopy observations show no evidence of tra nsformation induced plasticity. Wear is explained as being due to subs urface fatigue, with cracks readily nucleated at plastically deformed graphite nodules, the wear controlling mechanism being the crack growt h stage when wear shows a dependence on applied load and austempering temperature.