STUDY OF WEAR OF AS-CAST AND HEAT-TREATED SPHEROIDAL GRAPHITE CAST-IRON UNDER DRY SLIDING CONDITIONS

Wear behaviour of as-cast and heat-treated spheroidal graphite (SG) cast iron has been studied under dry sliding conditions using a pin-on-disc type apparatus. Wear tests were carried out at a linear sliding speed of 0.88 m s(-1), under a constant load of 1.5 kg. All tests were performed in ambient air at room temperature. Extent of wear damage and wear mechanisms were investigated by means of weight loss measurement, optical microscopy, microhardness measurement and X-ray diffractometry on wear debris. The wear rate measured after 9500 m of sliding is found to be about three times higher in the as-cast sample than in the heat-treated material. In the case of the heat-treated material, abrasive wear is the main wear mechanism. A combination of adhesive wear, delamination and surface fatigue is believed to operate in the as-cast material.