INFLUENCE OF THERMAL TREATMENT ON THE SCC BEHAVIOR OF INCONEL ALLOY 600 AT CONTROLLED POTENTIALS IN 10% CAUSTIC SODA SOLUTIONS AT 315 C.

Abstract

Electrochemically controlled test methods used to determine the influence of thermal treatment on the stress corrosion cracking (SCC) resistance of Inconel alloy 600 (I-600) in deaerated 10% NaOH solutions at 315 C (600 F). Maximum susceptibility to SCC was observed when the electrode potential of the I-600 was held in the potential range corresponding to the active-passive transition region of the anodic polarization curve. The improved resistance to SCC propagation could be correlated with the presence of a semicontinuous grain boundary carbide precipitate and/or segregation of phosphorus to the grain boundaries.