Anodic polarization and stress corrosion cracking of mild steel in highly concentrated and hot caustic solutions

摘要

The paper presents first results of a research program to investigate the anodic polarization behavior of high concentration caustic solutions with and without alumina addition, and study the relationship of the polarization curves with the SCC-susceptibility in the respective solutions. Anodic polarization of the carbon steel in a 7.5N caustic solution at 100℃ suggests a regime of active-passive transition in the range of -850 mV to -750 mV. Simultaneous slow strain rate testing (SSRT) under imposed electrochemical conditions in the regime of active-passive transition suggested occurrence of stress corrosion cracking of the steel. Results of SSRT are corroborated by the fractography of the specimens.