PROBING INTO METHODS FOR STUDYING STRESS CORROSION CRACKING OF MECHANICAL ENGINEERING MATERIALS

摘要

Stress corrosion cracking (SCC) is one of the main corrosion failure modes of mechanical engineering materials. Techniques of SCC testing, electrochemical measurement and Auger electron spectroscopy (AES) analysis have been used to study SCC of 304 stainless steel (SS) in high temperature water and alloy 800 in hot caustic solution. The SCC susceptible potentials correspond to passive-transpassive (active) transition. Electrochemical polarization measurements of the alloys and pure metals are able to provide useful information on the correlation of activation-passivation of alloy to electrochemical behaviors of the main alloying elements in Fe-Cr-Ni alloys, which is also in good agreement with the results of surface film analyses. It is concluded that combination of SCC tests, polarization curves and AES analyses is informative for better understanding the SCC mechanism of Fe-Cr-Ni alloys.