Corrosion Resistance of Weathering Steels in Simulated South China Sea Atmospheric Environment

Objective To provide data support and theoretical basis for development of corrosion-resistant steel used in the South China Sea atmospheric environment, by comparing the corrosion resistance of several steels and analyzing shortages and merits of their performance. Methods Q235B, Q355 and Q500qE were chosen as study materials, and the corrosion resistance of the samples was investigated with neutral salt spray test methods to simulate the harsh atmosphere environment of South China Sea. The corrosion behavior and mechanism were further analyzed with the aids of surface morphology observation, corrosion weight loss and electrochemical measurement. Results Surface of Q235B was first completely covered by corrosion products and the corrosion rates were always higher than that of the other two materials. Surface protective film of Q355 and Q500qE played a role of delaying corrosion process at the early stage, among which Q500qE had the maximum polarization resistance and the most flat corrosion morphology. Conclusion Under the simu-lated South China Sea atmospheric environment, the corrosion resistance rank order of three materials was: Q500qE〉 Q355〉 Q235B.