Combined effects of chloride ion and dissolved oxygen on SCC growth of low-alloy steels in high temperature water

Abstract

It has recently been recognized that stress corrosion cracking (SCC) of low-alloy steels (LAS) can be significantly accelerated by ppb-levels of chloride ions. This paper evaluated the combined effects of chloride ions and dissolved oxygen (DO) on the SCC growth behaviour in LAS under simulated boiling water reactor (BWR) conditions. Crack growth rate (CGR) tests under 20 ppb chloride ion concentration showed that CGR was reduced by one to three orders of magnitude when DO was reduced. It was also shown that there is a DO threshold for crack growth/arrest.