Influence of severe surface plastic deformation induced by shot peening on microstructure and corrosion resistance of fine grained 316 L stainless steel

Abstract

The influence of a severe shot peening (SSP) treatment in corrosion resistance of AISI 316 L austenitic stainless steel was studied by different electrochemical measurements in 3.5% NaCl solution. SSP promoted the formation of ultrafine grains in the upper layer. The formation of strain induced martensite appears to be facilitated by twinning due to the induced severe plastic deformation. SSP treatment with subsequent low temperature annealing (350ºC) improved corrosion resistance. The distinction of corrosion resistance is attributed to the different mechanical and microstructural features caused by severe plastic deformation. The best properties and stability of passive film were corroborated from various electrochemical techniques: potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy.