Stress Corrosion Cracking Detection of Sensitized Stainless Steel 304 in Chloride Media by Using Electrochemical Impedance Spectroscopy (EIS)

Electrochemical impedance spectroscopy (EIS) was used to detect stress corrosion cracking (SCC) in stainless steel 304 alloy exposed to an aqueous environment at 120 °C. Stainless steel 304 alloy as u-bend was tested in the solution that contains 40 weight percent of magnesium chloride. U-bended samples were prepared according to ASTM G30. EIS measurements were always performed simultaneously on u-bend samples under stress and non-stress conditions. The results indicate that changes in phase shift versus time could be related to the stress corrosion cracking process. Stress corrosion cracking is detectable at a frequency of 23.95 Hz. EIS measurement can be used for SCC monitoring in u-bend samples. Finally, analysis of the fracture surface by using metallographic and SEM techniques confirmed the EIS results.