Key Factors and Applications of Cavitation Peening
The impacts generated when cavitation bubbles collapse can be used for the mechanical treatment of surfaces in the same way as shot peening. A peening method that uses cavitation impacts is called “cavitation peening”. In the present review, the principles of cavitation peening are explained in order to illustrate the difference between cavitation peening and water jet peening. The key factors in cavitation peening, such as the type of cavitating jet, the standoff distance, the nozzle geometry, the cavitation number, the processing speed, the nozzle throat diameter, the injection pressure and the tank pressure are shown with experimental results. A semi-empirical equation to predict the peening intensity for a given nozzle and given operating conditions is proposed. The results of practical applications of cavitation peening, such as improving the fatigue strength of a material or suppressing hydrogen embrittlement, are also shown and compared with the results from shot peening.
Keywords: cavitation peening; water jet peening; shot peening; fatigue strength; residual stress; cavitating jet; pulse laser