SUITABLE REGION OF HIGH-SPEED SUBMERGED WATER JETS FOR CUTTING AND PEENING

In order to establish useful techniques of cutting, drilling, peening and flushing by high-speed submerged water jets, we systematically observe the eroded surface on aluminum-alloy specimens in relation to the characteristics of cavitating jets, especially for the impinging jet through lucite specimens, for several types of nozzles. The impulsive pressures induced by the cavitating jets are also measured by means of pressure-sensitive film. It is concluded that the erosion characteristics are quite different in two typical standoff distances, i.e., the 1st and the 2nd peak. Cylindrical, small and deep pits predominantly occur at the 1 st peak, while small lots of plastic deformations predominantly occur in the 2nd peak. Therefore, the 1st peak is suitable for cutting, while the 2nd peak is suitable for peening.