Effect of Magnesium on Lead Induced Stress Corrosion Cracking of UNS N08800

Abstract

This research is devoted to the effect of different water chemistries on the passivity and stress corrosion cracking (SCC) of the steam generator tubing alloy. The stability of passive films on UNS N08800 was investigated using cyclic polarization curves, Mott-Schottky measurements, SIMS and XPS. The SCC susceptibility was evaluated with constant extension rate tensile (CERT) tests in simulated neutral crevice chemistries at 300 C. It was found that the SCC susceptibility could be well correlated to the passivity degradation caused by harmful species such as lead. An interaction between lead and magnesium could happen at elevated temperature.