Characterization of Blasted Austenitic Stainless Steel and its Corrosion Resistance

It is known that the corrosion resistance of stainless steel is deterioratedby blasting but the reason for this deterioration is not clear. Blastedaustenitic stainless steel plate (JIS-SUS304) has been characterized withcomparison to the scraped and non-blasted specimens. The surfaceroughness of the blasted specimen is larger than that of materials finishedwith #180 paper. A martensite phase is formed in the surface layer of bothblasted and scraped specimens. Compressive residual stress is generated inthe blasted specimen and the maximum residual stress is formed at 50 to100 μm from the surface. The corrosion potentials of the blasted specimenand subsequently solution treated specimen are lower than that of thenon-blasted specimen. The passivation current densities of the blastedspecimens are higher those of the non-blasted specimen. The blastedspecimen and the subsequently solution treated specimen exhibit rust in 5%sodium chloride solution; while the non-blasted specimen and groundspecimen do not rust in the solution. It is concluded that the deterioration ofcorrosion resistance of austenitic stainless steel through blasting is causedby the roughed morphology of the surface