Failure Analysis of Corrosion Cracking of Incoloy 800/840 Heating Pipe

Accidents of tube explosion and electric leakage happened in an electric water heater in which Incoloy 800/840 were used.The influence of chloride ion on pitting corrosion performance and security threshold of chloride concentrations were studied by critical pitting temperature (CPT) testing and polarization curves.The results of comparing the morphology and corrosion resistance of heating tubes before and after production process showed that the production process had an effect on the pitting corrosion resistance of heating tubes.The high concentration of chloride ions accelerated the pitting corrosion and the stress corrosion cracking induced by pitting.