Modeling of Combined Anodic Dissolution/Hydrogen-Assisted Stress Corrosion Cracking of Low-Alloyed Power Plant Steels in High-Temperature Water Environments

Abstract

High-temperature slow strain rate testing (SSRT) – ductility data from cathodic hydrogen charging of 10CrMo910 and 7CrMoVTiB1010 are implemented into a mathematical model of stress corrosion cracking (SCC) at various operational conditions including temperatures, pH, and dissolved hydrogen/oxygen contents as well as global stresses and material properties. The results show that, as a consequence of experimentally verified local acidification at initial anodic path corrosion, subsequent local hydrogen-assisted cracking can be a controlling factor for SCC in high-temperature water. As a particular effect at global stresses close to the yield point, operational temperatures around 270°C exhibit peak crack growth rates depending on dissolved hydrogen, oxygen, pH, and global stress, which has been found to be consistent for both experimental studies and mathematical modeling.