抄録
In order to strengthen materials, the improvement of residual stress in stainless steel by using a cavitating jet was investigated. In case of cavitating jet, the cavitation intensity can be controlled by hydraulic parameters such as upstream pressure and downstream pressure. In general, cavitation produces damage on hydraulic machinery. However, at the initial stage of cavitation erosion process, plastic deformation takes place on the material surface, then it is possible to do peening without damage considering the cavitation intensity and the exposure time. In order to evidence the suitable condition on the improvement of residual stress by the cavitating jet, the residual stress in SUS304 and SUS316 was examined. The three normal stresses in different directions were measured by X-ray diffraction method, then the principal stresses were calculated. Both principal stresses were changed from tension to compression within 10 seconds by the cavitating jet. The compressive stress resulted by the cavitating jet was saturated after a certain time. It was concluded that the cavitating jet improved the residual stress in stainless steel SUS316 as well as SUS304.
