Effect of Deformation-Induced Martensite on the General Corrosion of SUS304 Stainless Steel in H2SO4-NaCl Solution

The effect of the deformation-induce martensite (α′) on the general corrosion of SUS304 austenite stainless steel in dilute H2SO4-NaCl solution was investigated by means of an electrochemical measurements and optical microscopic observation.The main results obtained are summarized as follows:(1) The corrosion resistance of SUS304 stainless steel in the active state region decreases with increasing volume fraction of martensite, decreasing of the solution and increasing solution temperature.(2) The corrosion of SUS304 steel containing martensite in the active state region is almost uniform. However, the selective dissolution of the martensitic phase in the specimens occurs.(3) The corrosion rate of the martensitic phase is about 1.65 times as large as that of the austenitic phase at the volume fractions of martensite below 50%. And at the volume fraction more than 50%, the rate is more enhanced with increasing volume fraction of martensite. However, no change in corrosion mechanism of SUS304 steel is observed regardless of whether martensitic phase is presented or not.