Elevated-Temperature Tribological Study of Interstitial-Free Steel Subjected to Shot Peening

The tribological behavior of steels at an elevated temperature plays a vital role in manufacturing processes like rolling, stamping, drawing, deep drawing, etc., where a prominent metal-to-metal contact demands a good wear resistance of the surface. The current investigation is based on improving the tribological behavior of interstitial-free steel by subjecting it to shot peening. The wear test was conducted at four different temperatures: 25, 100, 200, and 400 degrees C. The shot peening was done in two sets: conventionally shot peening and severe shot peening (SSP). The profile of the wear scar was analyzed in a profilometer, confirming the superiority of the SSPed sample in terms of smaller wear scar and lesser wear rate. Considering the temperature effects, the increase in wear resistance was more prominent at 400 degrees C due to the trace of thick oxide layers countering the ultrafine, fine oxide layers in the 200 and 100 degrees C wear conditions. The presence of protective alpha-Fe2O3 layers and lubricative Fe3O4 layers was advantageous in the tribological aspect, contributing to the formation of a thinner wear scar and lower wear rate. A prominent trace of counter body material was also found in the debris generated at 400 degrees C wear condition.