Improvement on the process capability of water cavitation peening by aeration

As a new surface enhancement technique, water cavitation peening (WCP) is used to introduce compressive residual stress in the superficial layer of metallic materials, thereby increasing the fatigue life of components. According to this method, a submerged high-speed water jet with cavitation is used, and the induced bubble collapse on the surface of the specimen will produce impact effect just like shot peening. In this study, a new ventilation nozzle with aeration is adopted to improve the process capability of WCP by increasing the impact pressure induced by the bubble collapse on the surface of components. As an example, a spring steel SAE 1070 plate specimen is treated by WCP with aeration, and the influence of aeration on the impact pressure and process capability of WCP is investigated. The results show that, with the air concentration of aerated jet-flow increasing, the impact pressure increases before the air concentration reaches 2.43% and decreases after the air concentration exceeds 2.43%. When the new ventilation nozzle with optimal aeration is adopted, the maximum process capability of WCP on the treated specimen is achieved.