Corrosion Resistance of Weathering Steel for New Coating-Free Building

Coating-free building weathering steel was developed by adding trace amount of Cr, Cu, Ni and Mo. The corrosion resistance properties of plain carbon steel and weathering steel in simulated industrial and marine atmospheric environments were compared and analyzed by cyclic wetting accelerated corrosion test and electrochemical corrosion test. The results show that the tensile strength, yield strength and impact energy at - 40 ℃ of weathering steel were obviously higher than those of plain carbon steel, and they had good strength and low temperature impact property. The corrosion rate of weathering steel was obviously lower than that of carbon steel in simulated industrial atmosphere and marine atmosphere. With the extension of corrosion time, the content of Fe₃O₄ in the rust layer of carbon steel and weathering steel increased gradually, and the content of β-FeOOH in carbon steel decreased and then increased, the volume ratio of α-FeOOH to γ-FeOOH (α/γ) increased and then decreased. While the content of β-FeOOH in weathering steel decreased and the value of α/γ gradually increased, indicating that β-FeOOH and γ-FeOOOH had a tendency to change towards a more stable α-FeOOH. The results of cyclic wetting accelerated corrosion test and electrochemical corrosion tests were consistent, that is, the corrosion resistance of weathering steel was better than that of carbon steel.