Potential Resistance of Alloy 82 Dissimilar Metal Welds to Primary Water Stress Corrosion Cracking

Abstract

Joints between carbon steel and Alloy 600, containing Alloy 82 weld metal, were exposed to a steam-hydrogen environment considered to simulate exposure to primary water conditions in nuclear power plants. A potentially protective external iron oxide film formed on the inner surface of the component. However, the chromium content throughout the weld is below that which would form an external chromium oxide. The results indicate that low chromium content could allow for internal oxidation below the external iron oxide which could increase susceptibility to primary water stress corrosion cracking (PWSCC) compared with an otherwise similar alloy, such as Alloy 800.