WEAR PERFORMANCE OF MARTENSITIC MEDIUM CARBON STEEL DEVELOPED VIA THERMAL

Thermal cycling martensitic (TCM) medium carbon steels offer an improved combination of strength and toughness as well as good wear resistance. Due to these improved properties, this recently developed steel has enormous potential to replace pearlitic rail steels or quench and tempered steels used in conventional gears and rolling element bearings. However, there is need for further investigations to determine the influence of heat treatment parameters and wear performance of Thermal cycling martensitic (TCM) steels. In this present work, medium carbon steel samples containing 0.4 wt% C, 0.28 wt% Si and 0.62 wt% Mn were subjected to thermal cycling treatment at laminarisation temperature of 743°C, 761°C, and 779°C and then tempered in a muffle furnace to obtain tempered martensitic microstructure. The dry sliding wear of martensitic steels was studied using a pin on disc tribometer and SEM (scanning electron microscope) was used to inspect the fractured parts of the specimens. The results indicate that the hardness increases with increasing laminarisation temperature. The wear test results show that the bulk temperature of the pin specimen increases with increasing sliding speed. The results also revealed that the martensitic steel developed exhibits highest wear resistance at 743 . It was found that the total specific wear rate (SWR) decreases with increasing sliding speed. However, the wear resistance does not primarily depend upon the hardness, but on the microstructure and toughness of materials.