: The effect of Si content (0.12%, 0.34%, and 0.48%) on the corrosion behavior of weathering steel in a simulated marine environment was investigated in a dry/wet alternating cycle corrosion experiment. Corrosion weight gain, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical methods were used to measure the regularity and nature of the rust. The results show that the corrosion process could be divided into an initial stage where the corrosion rate increased and a later stage where the corrosion rate decreased before remaining stable. The corrosion rate was the lowest for a Si content in the weathering steel of 0.48%. The corrosion products of all three steel groups contains α-FeOOH, β-FeOOH, γ-FeOOH, Fe3O4, and large amounts of amorphous compounds. Furthermore, Si benefits the transformation of β-FeOOH and γ-FeOOH to stable phases. The addition of the Si alloying element is beneficial to the formation of dense and compact rust layers that enhance the electrochemical resistance of weathering steel and silicon oxide influences the self-corrosion potential of the corrosion products.

In this paper, the effect of sulfur dioxide (SO 2 ) on the corrosion behavior of weathering steel with different copper (Cu) contents in a simulated industrial environment was studied. The results showed that the corrosion occurred in three distinct stages with the corrosion kinetics characterized via the parameter of 'n'. For the first and second stage with n>1 and n<1, the corrosion of weathering steel was accelerated and reduced, respectively. The third stage witnessed the minimum value of n, indicating a lowest corrosion rate. As the Cu content increased from 0.15% to 0.50%, the corrosion weight gained and corrosion rate remarkably decreased. In contrast, when the Cu contents increased from 0.50% to 0.70%, the corrosion rate began to slightly decrease. With the Cu addition, the stable α-FeOOH phase in the rust layer was refined, which increased the electrochemical impedance accordingly lowered the electrochemical reaction rate and ultimately enhanced the corrosion resistance. In this work, we have studied the corrosion mechanism of Cu element on the weathering steel in the industrial atmosphere, and studied the effect of Cu content on the corrosion resistance of weathering steel. The research shows that the content of the effect is not great, so the recommended amount of Cu in weathering steel is not more than 0.50%.