Experience with stress corrosion cracking in duplex stainless steels

摘要

In June 1989, the duplex stainless steel tubes of a reactor started leaking, and on further investigation, it was found that a large number of the tubes of the reactor had failed. As these tubes normally perform well and failures do not occur easily, a failure investigation was performed in order to determine the cause of this problem. Metallurgical investigation indicated that the failure of these duplex steel tubes was caused by stress corrosion cracking arising from chorides in the cooling water. It was found that the cooling water is heated weekly to its boiling point, causing concentration of the chloride content on the tubes. During subsequent wetting of the tubes for normal production, the water would have a very high chloride content - the cause of cracking.