Relationship between anodic polarization behavior and stress corrosion cracking (SCC) susceptibility of SUS 304 stainless steel has been studied in both high temperature water and chloride solutions containing oxyanions such as MoO42-, WO42-, CrO42-and VO3-. Results obtained are as follows: 1) Intergranular stress corrosion cracking (IGSCC) of sensitized SUS 304 stainless steel in water at 250C occurred at the potential range where Cr depleted zones along grain boundaries dissolve more rapidly

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... han the matrix, e. x., above -100mV (vs. Ag/AgCl) in the constant load SCC test. 2) Addition of the oxyanions more than 3x10-2M suppresses completely the IGSCC of sensitized SUS 304 stainless steel. The IGSCC inhibition by MoO42-seems to be achieved by decreasing the dissolution rate of Cr depleted zones to the level of the matrix owing to the formation of chromium rich oxide film. 3) Addition of the oxyanions more than 2x10-2M suppresses completely the transgranular stress corrosion cracking [TGSCC] of SUS 304 stainless steel in high temperature water containing Cl-. MoO42-makes the corrosion potential of SUS 304 stainless steel in the solution with MoO42more negative than in the solution without MoO42-and strengthens the surface oxide film rich in chromium oxide enough to resist Cl-attack.