Corrosion behavior of steel exposed to "zero" pollution atmosphere environment for 20 years

In this study, the corrosion behavior of Q235 carbon steel, 09CuPTiRE weathering steel and X60 pipeline steel after 20 years exposure in "zero" pollution atmosphere environment was investigated by corrosion rate analysis, macroscopic observation, scanning electron microscopy, X-ray diffraction, white light interferometers and electrochemical analysis were conducted to analyze. The results showed that the corrosion rate of the three kinds of steels increases first and then decreases with time, and the results indicated that the empirical formula D=Atn was suitable for corrosion kinetics of three materials, and the three kinds of steels all form a relatively dense rust layer, which can effectively protect the metal matrix, inhibit the corrosion process and reduce the rate of corrosion. Under the same exposure time and the same corrosion conditions, the corrosion degree of the three materials is: X60 pipeline steel > Q235 Carbon steel >09CuPTiRE Weathering steel, three kinds of steel corrosion products are the same, only α-FeOOH and γ-FeOOH exist in the rust layer, and the relative content of α-FeOOH is more than γ-FeOOH of each steel in both skyward side and fieldward sides. X60 Pipeline steel has the worst corrosion resistance, and 09CuPTiRE weathering steel has the best corrosion resistance, so 09CuPTiRE weathering steel has better adaptability to this environment.