Influence of electrolytic plasma process on corrosion property of peened 304 austenitic stainless steel

An electrolytic plasma process (EPP) was applied onto shot peened surface of 304 stainless steel (SS) and the corrosion behavior were studied with different treatment parameters. The peening process on 304 SS was performed by a ball milling machine. Although the peening process may improve the material strength, due to the refinement of γ phase and γ → martensite (α') transformation, the low corrosion resistance of martensite limits the application of the resultant material. In this paper, EPP was applied onto the peened surfaces for a rapid surface annealing. After EPP, the deformation-induced martensite was partially reverted back to austenite phase. X-ray diffraction, hardness, and SEM study were employed to manifest the major transformations. Optimal EPP treatment could achieve both high strength and corrosion resistance on steel surfaces.