Study On Corrosion Resistance Of Weathering Steel In High Humidity And Heat Ocean Atmosphere

Marine atmospheric corrosion environment in all kinds of atmospheric corrosion environment is the worst, and high humidity marine atmospheric corrosion due to the strong radiation, high concentration of chloride ion, dry wet circulation velocity faster is become the difficult point in the marine atmospheric corrosion. South China Sea region belong to such atmosphere, requires very high resistance to corrosion of the materials, so far, existing low alloy weathering steel under corrosion environment of the South China Sea near the coast are unable to obtain good results. But the South China Sea area is rich in natural resources, huge reserves of oil and gas, islands and infrastructure with steel corrosion problems in urgent need of solution. Therefore, the study of high humidity marine atmospheric corrosion environment characteristics, develop a sense of weathering steel having superior performance in high humidity marine atmosphere for the construction and development of China’s marine engineering is very important.In this paper, using wet/dry cyclic test simulates high humidity marine atmosphere by changing the different experimental conditions to study the corrosion of law about different temperatures and relative humidity of metal. With corrosion inhibitors principle analyzes the effects of Sn, Sb elements on the corrosion resistance of carbon steel. And refining a tin-containing weathering steel, Weathering steel containing tin and antimony. Indoor cycle immersion corrosion test match them performance advantages and disadvantages between the traditional weathering steel. And explore the mechanism of corrosion, rust formation and failure mechanisms by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical methods.The experimental results showed that under high humidity marine atmosphere, temperature at 35℃-55℃, the corrosion rate of the steel test increases with increasing temperature, and more thick layer of rust, loose rust degree is gradually increased, Meanwhile corrosion product Fe3O4 content increases, reducing the γ-FeOOH content is not conducive to the formation of a protective rust layer of α-FeOOH. Relative humidity at 60% RH-80% RH, the corrosion rate of the steel test with increasing relative humidity increases, more and more thick layer of rust, rust damage little change in corrosion rate with increasing relative humidity is non linear change, the higher the relative humidity, the corrosion rate of the test steels increase smaller rust layer phase composition without major changes.Sn-containing、Sb and Sn-containing weathering steel compared with conventional weathering steel corrosion rate decreases, more uniform rust layer production, the thickness has been reduced, with better corrosion resistance. Tin and antimony weathering steel than conventional weathering steel would like to make the initial corrosion of bare steel surface corrosion potential increases, the corrosion current density is reduced by increasing the resistance of the electric double layer, inhibiting ion exchange to achieve slow down the corrosion rate, improve its resistance corrosion resistance. After the formation of rust, corrosion potential to make rust layer increases, the corrosion current density decreases, the anodic dissolution of weathering steel inhibited, while the rust resistance Rr and Rt reaction resistance at elevated bonded to the substrate, enhancing rust steel substrate layer protection.