Abstract
The corrosion morphology of carbon steel varies with environmental factors in fresh water. General corrosion and localized corrosion are known as the major morphologies. In the case of the general corrosion, the corrosion monitoring and the life prediction of the metal can be carried out without the difficulty. However in the case of the localized corrosion, the precise corrosion monitoring is difficult and the unexpected trouble like water leakage may happen. Therefore, the diagnosis method of water quality for carbon steel corrosion in fresh water is required strongly. In this study, we propose a simple method to classify the corrosion category of the carbon steel in the fresh water by combining potentiodynamic polarization curve measurement and potentiometry at a constant current.