Effects of temperature and aggressive anions on corrosion of carbon steel in potable water

Experiments on the corrosion of carbon steel in three kinds of artificial potable waters containing different concentrations of aggressive anions, Cl− and SO42-, open to air in the temperature range from 5 to 60 °C were conducted using weight loss and electrochemical methods. The corrosion rate increased in proportion to the concentration of aggressive anions and with increasing temperature. At lower concentrations of aggressive anions and temperatures, the corrosion rate was lower and the corrosion potential was higher, at intermediate concentrations and temperatures, the corrosion rate increased logarithmically with decreasing potential, and at higher concentrations and temperatures, the corrosion rate was higher and the potential was lower. The corrosion behavior in potable water can be determined by the balance between inhibitive action of oxygen (passive film formation) and aggressive action of Cl− and SO42- ions.