The Effect of Shot-Peening Time on Tribological Behavior of AISI5160 Steel

Abstract

The aim of this study is to investigate the tribological behavior of disks made of AISI5160 steel that were austempered at 288 °C for 120 min until the bainite microstructure was completely formed. Then shot peening was applied for 0 (not shot peened), 1, 2, 3, 4, or 5 min. Before tribotests, x-ray diffraction (XRD) was employed to measure the compressive residual stress. A rotary test rig was employed to run the tribotests, and scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were employed to analyze the worn surfaces post tribotests. The compressive residual stress increased as the shot-peening time increased. Shot peening provided lower protection against wear than disk samples without shot peening. Wear debris increased during the tribotests on disk samples that had longer shot peening and led to more wear loss. This occurred because longer shot-peening time generated more cracks than shorter shot peening or no shot peening before tribotests. A limited amount of debris was found to protect the balls against wear; however, additional debris increased wear volume on the ball and led to plowing wear as well.

Keywords:

• Shot peening
• compressive residual stress
• debris
• wear
• friction