A newly developed rust layer on Q370qENH weathering steel (sample C) was studied under dry–wet cycle test of 3.5 wt.% NaCl solution and salt spray test, compared with the bare weathering steel (sample A) and the weathering steel with additive contents (CuSO₄ 0.2, FeSO₄ 0.1, NaHSO₃ 0.02, NaCl 0.02, Na₂HPO₄ 0.01, and water balance, in mass%, termed as sample B). Corrosion mechanism of Q370qENH weathering steel after different surface treatments was investigated by means of surface potential scanning, mass change, polarization curve, and X-ray diffraction. The results of X-ray diffraction indicate that rust of bare weathering steel has rare Fe₃O₄, and a dense oxide layer mainly composed of Fe₃O₄ is formed on rust of both sample B and sample C. The surface potential of sample A gradually increases to − 0.2 V in the dry–wet cycle test, while the surface potential of sample A maintains at about − 0.6 V in the salt spray test. The surface potential of sample B and sample C is higher than that of sample A in the early stage and remains stable during the short-term accelerated corrosion test. Moreover, the mass change of sample C gradually stabilizes with time in the dry–wet cycle and salt spray test. The corrosion current of the sample A is lower than that of sample C in the initial stage of short-term accelerated corrosion test. However, the corrosion current of sample C is smaller than that of the sample A in the experiment. The main components of the deep rust of sample A are γ-FeOOH and α-FeOOH, while those of the deep rust of sample B and sample C are Fe₃O₄.

通过 3.5 wt.% NaCl 溶液的干湿循环试验和盐雾试验，研究了 Q370qENH 耐候钢（样品 C）上新开发的锈层，并与裸耐候钢（样品 A）和添加含量的耐候钢进行了比较（CuSO ₄ 0.2、FeSO ₄ 0.1、NaHSO ₃ 0.02、NaCl 0.02、Na ₂ HPO ₄ 0.01 和水平衡，以质量％计，称为样品 B）。通过表面电位扫描、质量变化、极化曲线、X射线衍射等方法研究了Q370qENH耐候钢不同表面处理后的腐蚀机理。X射线衍射结果表明，裸露的耐候钢锈中含有稀有的Fe ₃ O ₄, 以及主要由 Fe ₃ O _{4组成的致密氧化层}样品 B 和样品 C 都生锈。样品 A 的表面电位在干湿循环试验中逐渐升高到 - 0.2 V，而样品 A 的表面电位在盐雾试验中保持在 - 0.6 V 左右. 样品 B 和样品 C 的表面电位在早期高于样品 A，在短期加速腐蚀试验中保持稳定。此外，在干湿循环和盐雾试验中，样品 C 的质量变化随时间逐渐稳定。在短期加速腐蚀试验初期，样品A的腐蚀电流低于样品C。但实验中样品C的腐蚀电流小于样品A的腐蚀电流。样品A深锈的主要成分是γ-FeOOH和α-FeO​​OH，₃ O ₄。