Effect of surface machining on the corrosion behaviour of 316 austenitic stainless steel in simulated PWR water

The corrosion behaviour of 316 austenitic stainless steel with different surface machining processes in simulated pressure water reactor primary environment was investigated. The oxide films related to three surface conditions were characterized by using SEM, TEM and XPS. The results showed that the machined surface conditions affected the thickness and elemental distribution of the oxide films composed of a double-layer structure. The more heavily cold worked layer results in less chromium enrichment in the inner film, and more nickel enrichment at the oxide/metal interface. Meanwhile, unduly chromium depletion beneath the oxide film was observed on the machined surfaces.