Effects of SO42− concentration on corrosion behaviour of carbon steels

Abstract

Purpose – The purpose of this paper was to investigate the effects of SO42− concentration on the corrosion behaviour of T23 and T12 steels in simulated water chemistry condition solution of 600 MW fossil-fired power boilers. Design/methodology/approach – The influence and mechanism of SO42− ions on the pitting corrosion of T23 and T12 steels in simulated oxygenated treatment water chemistry solution was studied using electrochemical potentiodynamic polarization scans and electrochemical impedance spectroscopy. Findings – The results showed that T23 and T12 were susceptible to pitting corrosion in the simulated solution with full SO42− concentration for the competitive adsorption of OH− and SO42− on the surface of steels. The pitting sensitivity of the steels improved with increasing SO42− concentration. The corrosion resistance for SO42− of T23 was stronger than that for T12. Originality/value – This study is an attempt to provide direction for regulating the concentration of SO42− in boiler water and for selecting the material for boiler water wall tubes.