Weather resistance of low carbon high performance bridge steel

Weathering resistance of low carbon (0.03–0.05wt.% C) micro-alloyed bainitic steel made in laboratory scale was studied and compared with that of conventional weathering steel 09CuPCrNi by wet–dry cycle test in a 3.5wt.% NaCl aqueous solution. The results show that corrosion resistance of the bainitic steel is better than that of 09CuPCrNi, attributed to homogenous bainite microstructure. Subsequently, this steel was trial-manufactured in industrial plant, and the yield strength of which achieves 500MPa grade, additionally, the gauge of plate steel reaches 80mm, and excellent mechanical properties across the thickness section are obtained. Microstructures of the plate are homogenous bainite at surface layer, which contributes to excellent corrosion resistance of the industry trail steel.