添加微量Cr、Cu、Ni和Mo元素开发了免涂装建筑用耐候钢，通过周期浸润加速腐蚀试验和电化学腐蚀试验，对比分析了普通碳素钢和耐候钢在模拟工业大气和海洋大气环境中的耐腐蚀性能。结果表明：耐候钢的抗拉强度、屈服强度和-40℃冲击功均明显高于普通碳素钢的，具有较好的强度和低温冲击性能；在模拟工业大气和海洋大气中，耐候钢的腐蚀速率明显小于碳素钢的；随着腐蚀时间延长，碳素钢和耐候钢锈层中Fe₃O₄含量逐渐增加，碳素钢中β-FeOOH含量先减小而后增大，α-FeOOH相与γ-FeOOH相的体积比（α/γ）值先增大而后减小，而耐候钢中β-FeOOH含量不断减小，α/γ值逐渐增大，表明β-FeOOH和γ-FeOOH有朝着更加稳定的α-FeOOH转变的趋势；周期浸润加速腐蚀试验和电化学腐蚀试验结果相吻合，即耐候钢的耐腐蚀性能优于碳素钢的。

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.