Atmospheric Corrosion Behavior of Q235 Steel in Northern Hebei Region

The atmospheric corrosion test was conducted on Q235 steel in northern Hebei region (Tangshan, Qinhuangdao, Langfang, Chengde, and Zhangjiakou city) for 1 a, and the corrosion rates of Q235 steel in different cities were compared. The effects of Cl^- deposition rate, SO₂ content and humidity in the atmospheric environment at center positions of five cities (Angezhuang, Tianma, Bazhou, Longcheng, Wanquan) on the corrosion rate of Q235 steel were studied, and the morphology of the corrosion products was observed. The results show that the corrosion rate of Q235 steel decreased gradually from southeast to northwest. The effect of Cl^- on corrosion rate was relatively small because of the relatively low deposition rate. The influence of SO₂ content on corrosion rate was greater than that of Cl^-, and the influence of air relative humidity was the largest. The corrosion rate of Q235 steel at Angezhuang station was relatively fast, and the surface corrosion products were mainly lamellar γ-FeOOH, which had relatively small protective effect on the matrix. The corrosion rates at Bazhou and Tianma stations were the second, and the corrosion products were mainly cluster-shaped α-FeOOH. The corrosion rates at Wanquan and Longcheng stations were relatively slow, and the surface corrosion products were mainly cotton-flock-like α-FeOOH, which had relatively large protective effect on the matrix.