Evaluation of Peening Intensity of Cavitation Shotless Peening by Using Almen Strip(Student Poster Session)

Abstract

Cavitating jet can be used to strengthen metallic materials by introducing compressive residual stress into the surface in the same way as shot peening. This surface modification method is called "Cavitation shotless peening", since shot used in shot peening is not required and the impacts of cavitation babble collapses is utilized to peen the surface. In order to demonstrate the effectiveness of cavitation shotless peening, almen strip was exposed to the cavitating jet at several jet conditions. The almen strip is generally used for evaluation of the peening intensity of shot peening by measurement of whose arc height. The almen strip exposed to the cavitating jet bent and the arc height occurred depending upon the jet parameters such as cavitation number, standoff distance, and nozzle diameter. Two types of almen strip, A and N, having different thickness, were used in this study. In the case of cavitation shotless peening, the relation between arc height of thin almen strip and that of thick one was different from that of shot peening. Furthermore, the surface roughness of almen strip exposed to the cavitating jet was significantly smoother than that of shot peening. It is concluded that cavitation shotless peening is effective in the surface modification and that the peening intensity of cavitation shotless peening changing with cavitating jet conditions can be evaluated by using almen strip.