Corrosion behavior of Q235 steel in Beijing soil environment

The corrosion behavior of the Q235 carbon steel in Beijing soil environment was investigated by burying test in nature field for one year, two years and two point five years, electrochemical impedance spectroscopy(EIS) test, morphology observations, and weight-loss method. The results showed that the general corrosion occurred mainly on the Q235 carbon steel in Beijing soil, but the serious pitting corrosion was observed locally. With the increase of burying time, the average depth of pitting and the deepest depth of pitting both increased, while the corrosion rate increased first and then decreased. The corrosion product of the Q235 carbon steel mainly consisted of α-FeOOH, β-FeOOH, γ-FeOOH, and γ-Fe₂O₃. With the increase of burying time, the content of α-FeOOH increased, meanwhile the compactness and continuity of the corrosion product layer improved, but it could not protect the substrate.