Stress corrosion cracking behavior of AISI 316L stainless steel treated by surface mechanical grinding

•Residual tensile stress induced by turning and milling is effectively eliminated by SMGT process.•SMGT process produces dense ultrafine grains in the surface layer.•SCC crack initiation and propagation are suppressed by SMGT process.•The mechanism of SMGT effects on SCC of AISI 316L stainless steel is revealed. The effects of surface mechanical grinding treatment (SMGT) on stress corrosion cracking (SCC) behavior of machined 316L stainless steel surface were investigated by comparing to those of turned and milled surfaces. The surface stress state, roughness, microstructure, and microhardness induced by the different surface machining processes were tested and analyzed. The SCC tests on the turned, milled and SMGT samples were conducted in boiling MgCl2 solution at 155 ℃, and the crack morphologies were analyzed in detail to establish the relationship between the surface integrities and the resulting SCC behavior. The findings indicated that the SMGT altered the SCC initiation behavior and improved SCC resistance of the turned and milled surfaces of 316L stainless steel, and the surface stress state, microstructure refinement and surface strengthening induced by SMGT contributed to the improvement of the SCC resistance.