Enhancing stress corrosion cracking resistance of machined surface via surface mechanical grinding treatment for AISI 316 L stainless steel

Abstract

The mechanical properties, microstructures and corrosion resistance of turned, milled and surface mechanical grinding treatment (SMGT) processed surfaces were investigated through the surface stress measurement, microhardness, SEM, TEM, TKD, XRD and electrochemical corrosion analysis. The stress corrosion cracking (SCC) initiation behavior of three types of treated surfaces in boiling MgCl 2 solution were assessed and compared. The experimental results indicated that the SMGT processed surface inhibited the SCC initiation at the surface stress as high as 874 MPa. The enhancement of SCC resistance was attributed to the SMGT-induced dense ultrafine-grained (UFG) layer, gradient grain refinement and better corrosion resistance, resulting in the high yield strength and high critical stress of SCC initiation. • The surface mechanical grinding treatment generated a dense ultrafine-grained (UFG) layer and low residual stress on processed surface. • The dense UFG layer successfully suppressed the SCC initiation at the surface tensile stress as high as 874 MPa. • The mechanisms of SMGT improving the SCC resistance were attributed to the high yield strength combined with better corrosion resistance of the UFG layer, increasing the σ SCCof crack initiation. • The SMGT can serve as a promising strategy to enhance the SCC resistance for machined 316 L stainless steel surface.