The influence of chromium content on the electrochemical behavior of weathering steels

• Electrochemical measurement on steels with various Cr contents is performed.
• NaHSO3 solution is used as electrolyte to simulate industrial atmosphere.
• Increasing Cr content leads to notably positive shift of corrosion potential.
• Increasing Cr content results in decline of corrosion current density.
• Electrochemical behavior is relevant to the characteristics of rust layer.

To investigate the influence of chromium content on corrosion characteristics of weathering steels, the electrochemical measurements were performed on the steels containing 0–9% Cr (wt.%) in NaHSO3 aqueous solution. The results indicated that the open circuit potential of these steels shifted to the positive direction remarkably, because the additions of Cr improved the passivation capability of the steels. The corrosion current density of the steels containing more than 7% Cr (wt.%) decreased significantly after pre-rusted treatment, implying the corrosion resistance could be enhanced by the formation of protective goethite rust layer.