Waterjet Peening At 600MPa: A First Investigation

An experimental study was conducted to explore the high-pressure waterjet (WJ) peening at 600MPa on the surface integrity and texture of metals. The concept of larger droplet size and multiple droplet impacts resulting from an ultra high-pressure waterjet (UHPWJ) was used to explore and develop the peening process. A combination of microstructure analysis, microhardness measurements, and profilometry were used in determining the depth of plastic deformation and surface texture that result from the surface treatment process. It was found that waterjet peening at 600MPa induces plastic deformation to greater depths in the sub-surface layer of metals than laser shock peening. The degree of plastic deformation and the state of material surface were found to be strongly dependent on the peening conditions and desired surface roughness. Based on these first investigation results, water peening at 600MPa may serve as a new method for introducing compressive residual stresses in engineering components.