Stress corrosion cracking of ultrahigh strength martensite steel Cr_9Ni_5MoCo_(14) in 3.5% NaCl solution

摘要

This paper describes the stress corrosion cracking (SCC) mechanism of a new structural ultrahigh strength martensite steel Cr_9Ni_5MoCo_(14)and how cathodic potential affects the SCC susceptibility in 3.5% NaCl solution. At open circuit potential (OCP), SCC cracks initiate from pittings, and SCC mechanism involves anodic dissolution. Within the ideal cathodic protective potential range from -500 mV to -700 mV, the specimen has a greater SCC resistance, and SCC mechanism is mixed-controlled by both anodic dissolution and hydrogen-induced cracking. Significant hydrogen-induced crack is observed at -1100 mV which can be attributed to a significant amount of hydrogen atoms involving in the cracking processes.