Corrosion behaviour of S500AW railway steel in a simulated industrial atmospheric environment

The corrosion behaviours of Q345B carbon steel and S500AW railway steel for railways were evaluated in a simulated industrial atmosphere, and the corrosion mechanism of S500AW railway steel was explored. Periodic immersion corrosion experiments were carried out on two types of steel, and the experimental periods were divided into 24 h, 120 h, 240 h and 360 h. The corrosion weight loss and corrosion rate were calculated by the weight loss method. The corrosion potentials and corrosion current densities of the two types of steel in four cycles were analysed by electrochemical experiments. The macromorphology, micromorphology and corrosion product composition were analysed to evaluate the corrosion behaviour of Q345B and S500AW. The corrosion rate of S500AW in the periodic immersion corrosion experiments was lower than that of Q345B. With an extension of the experiment time, the proportion of alpha-FeOOH in the rust layer increased. In the simulated industrial atmosphere, the corrosion resistance of S500AW was better than that of Q345B. During the 360-h immersion experiments, the value of alpha/gamma of Q345B increased at first and then appears to be steady, while the alpha/gamma value of S500AW continued to increase.