G0300907 Measurement of coefficient of restitution by shot peening and its application to hardness test

Abstract

Shot peening is the method that hard particles are shot on material surface. With this method, compressive residual stress and work hardening are induced and hard layer is fabricated on the material surface. Finally, the treated material has greater fatigue strength and abrasion resistance property. In shot peening, shot particles hit on the material surface and rebound, and its coefficient of restitution depends on material properties such as yield stress. Therefore, we carried out some experiments in order to investigate the relationship between the coefficient of restitution and yield stress. The results showed that the yield stress is proportional to e1'6. The proposed method to measure the yield stress is valid under high temperature condition. From the numerical analysis, the strain rate is about 7400 s^<-1>. Therefore, it is concluded that measuring yield stress at local area under high temperature and high strain rate is possible by using shot peening.