Effect of Shot Size and Peening Pressure on the Low Stress Abrasive Wear Behavior of Inter Critically Annealed Medium Carbon Steel

The effect of shot size and peening pressure on abrasive wear of medium carbon steel after intercritical annealing has been studied. The peening pressure was varied between 3-5 bar and shot size in the range 0.6-1 mm. The steel samples were polished and then shot peened. The peening intensity was kept constant to 0.27A using varying peening parameters (shot size: between 0.6 to 1.0 mm and peening pressure: between 3 to 5 bar). The low stress abrasive wear test was conducted using dry abrasion test rig TR-38 at an applied load of 50 N. The wear tests were conducted upto 3000 m sliding distance and the wear rate was measured at every interval of 300 m. It was noted in general, that the wear rate decreases with increase in sliding distance. The minimum wear rate is observed at 0.8 mm shot size and 4 bar peening pressure. Further, decrease or increase in peening pressure or shot size leads to higher wear rate. This has been understood from the surface and the subsurface microstructures.