Improving the mechanical properties of 304 stainless steel using waterjet peening

Abstract

In this study, waterjet peening (WJP) treatments under different water pressures were utilized to improve the mechanical properties of 304 stainless steel. The surface morphologies, microstructures, phases, and mechanical properties under different pressures in the WJP process were systematically investigated. The results show that WJP treatments successfully introduced a hardening layer and residual compressive stress. The optimal hardening layer, hardness, residual compressive stress, tensile strength, and ductility were all recorded at the pressure of 200 MPa. The improved hardness, tensile strength, and ductility of 304 stainless steel treated with WJP treatments at the pressure of 200 MPa can be attributed to the hardening layer with much apparent grain refinement effect, phase transformation, smaller surface roughness, and a specific residual compressive stress, as compared with the WJP treatments under other water pressures.