Study on Electrochemical Monitoring Methods for Stress Corrosion of Typical Stainless Steels

摘要

Stress corrosion cracking (SCC) poses a significant threat to the safe operation of stainless steel components in critical engineering fields such as nuclear power, petrochemicals, aerospace, and marine vessels. Due to the complexity of its mechanisms and the numerous influencing factors, effective prevention and control of SCC remain challenging. As a result, the mechanisms, diagnostics, and assess ment of stress corrosion in stainless steel have long been areas of extensive focus in both industry and academia. SCC in stainless steel is an interactive process involving fracture behavior, passive film failure, and electrochemical behavior. Detailed analysis of failure cases, identification of occurrence patterns, and examination of the primary mechanisms and internal and external microstructural influences are crucial for advancing monitoring, detection, and prevention technologies for SCC. This study summarizes the research progress of our team in understanding the microstructural characteristics and monitoring methods for typical stainless steel SCC failures. Our findings indicate that the SCC behavior of stainless steel aligns with a non-steady-state electrochemical model, with the corrosion fracture mechanism being controlled by a mixed mode of anodic dissolution and hydrogen embrittlement. Furthermore, various precipitates and deformation structures resulting from processes such as cold deformation, sensitization, and heat treatment significantly influence the initiation of SCC. The study elucidates the detailed mechanisms and patterns of these effects. These insights not only enhance the understanding of the mechanisms underlying stainless steel SCC but also provide valuable guidance for preventing SCC and optimizing the corrosion resistance of stainless steel, offering both scientific and practical significance.