An experimental study of residual stress induced by ultrasonic shot peening

Ultrasonic shot peening treatment is used to treat structural surfaces, which can enhance the overall strength, stiffness and fatigue life of the treated material. This process induces large residual stress. Since the thickness affected by shot peening is only about 200–300 μm, a precise measurement of the residual stress distribution near the shot peening layer is difficult. In this paper, Moiré interferometry, a high-resolution optical technique, is used to measure the residual stress. It proves to be relatively accurate technique for the measurement of the residual stress distribution. The experimental results show that ultrasonic shot peening can cause a large compressive residual stress of up to 309 MPa on the material surface in soft steel.