Corrosion Failure Analysis of an Acid Corrosion Resistant Butterfly Valve in a Copper Smelter Acid Plant

The corrosion failure of acid resistant butterfly valve was analyzed by means of in-situ work condition investigation, chemical composition analysis, microstructure and corrosion morphology observation as well as electrochemical testing. The results show that the localized corrosion perforation and pits were due to casting defects. The main reason for heavy general corrosion was electrolytic corrosion because of anodic protection system.