Effect of hydrostatic extrusion on the corrosion resistance of Type 316 stainless steel

The corrosion resistance of Type 316 (UNS S31600) austenitic stainless steel in an aggressive environment containing Cl ions in the as-received state and after nanostructuraltzation caused by severe plastic deformation by hydrostatic extrusion (HE) was investigated. Transmission electron microscopy (TEM) was used to examine the structural changes introduced by the HE process. The effects of the surface oxide film on the corrosion resistance of Type 316 stainless steel in a borate buffer + 0.1 M sodium chloride (NaCl) solution and in a saline solution of 0.15 M NaCl were investigated using potentiodynamic polarization. Surface analytical techniques such as scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) were used to characterize the morphology and chemistry of the surface before and after HE.