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Atmospheric corrosion of carbon steels pre‐corroded by different pollutants

Carbon steels were pre‐corroded in atmospheres containing certain pollutants such as sulfur dioxide or hydrogen sulfide or nitrogen dioxide for certain period of time. Then the pre‐corroded samples were further exposed at two central test stations in the country to evaluate the influence of pre‐corrosion on the behavior of long‐term atmospheric corrosion of carbon steel by gravimetric measurement and rust examinations with FT‐IR and XRD. The results showed that the corrosion rates of every kind of carbon steel at Jiangjin station were two times higher than that at Beijing station. The influence of different pre‐corrosion conditions on the long‐term atmospheric corrosion of carbon steel was analyzed. It followed that the pre‐corrosion conditions made the long‐term atmospheric corrosion performance of three kinds of carbon steels different, but the differences were small. Among the three pollutants, NO2 showed the strongest influence to the process. As the exposure time was going on, all the samples corroded slowly at Beijing and Jiangjin stations.