Water jet peening nozzle, water jet peening apparatus, and water jet peening method

摘要

PROBLEM TO BE SOLVED: To provide a water jet peening (WJP) nozzle capable of further improving a residual stress of a WJP implementation target.SOLUTION: An injection nozzle 2 is configured so that an external cylinder 9 having a projection pipe 4 projecting from a tip end of a nozzle main body 3 and surrounding the projection pipe 4 is attached to the nozzle main body 3. The external cylinder 9 includes: an external cylinder base 10 surrounding the projection pipe 4 and attached to the nozzle main body 3; a cylindrical portion 10B connected to the external cylinder base 10; and an opening formation portion 11 connected to the cylindrical portion 10B and having an opening 13 formed therein. An injection area 17 formed in the external cylinder 9 communicates with an injection port 8 on a tip end of the projection pipe 4 and is surrounded by the external base 10, the cylindrical portion 10B, and the opening formation portion 11. A curved surface 12A that is convex outward from the injection area 17 is formed to face the injection area 17 over an opening 13-side end portion of the external base 10 and an inner surface of the cylindrical portion 10B.