Investigation of Flow Accelerated Corrosion Behavior of Carbon Steels and Low Alloy Steels via Synchrotron Scanning Tunneling X-ray Microscopy

摘要

Flow accelerated corrosion (FAC) is an environmental assisted degradation of pipeline materials, which is widely observed in carbon steel pipeline in nuclear power plants (NPPs) . In the equilibrium between the dissolution and the formation of magnetite at the metal/water interface, continuous wall thinning and eventually failure of the pipeline occurs. In this context, substitution of carbon steels into low alloy steels has been suggested since small amount of chromium effectively mitigate FAC. Recently, A335 P22 chromoly pipe is used as a pipeline material for NPPs where FAC favored. However, the effects of chromium and molybdenum on FAC behavior of low alloy steels have not been clearly investigated. Generally, chromium and molybdenum are known as effective for general and localized corrosion, respectively, but most of the previous studies have focused on quantitative analysis.