结构钢在使用过程中，腐蚀行为是制约其使用寿命和安全性的重要环节，其中大气腐蚀影响显著。 为深入解析结构钢大气腐蚀行为，本研究采用 NaHSO3 溶液模拟工业大气环境进行加速腐蚀实验，研究了对比钢 Q345B 和耐候钢的腐蚀行为。 对试样的腐蚀失重进行分析，并计算腐蚀失重率，得出对比钢 Q345B 在腐蚀 168 h 时的腐蚀失重率为2.25 g/(m2·h)，而耐候钢仅为 1.74 g/(m2·h)，对比钢 Q345B 的腐蚀速率比耐候钢高。 利用 X 射线衍射对腐蚀产物物相进行鉴定，发现两种钢的主要腐蚀产物均为 α-FeOOH、γ-FeOOH、Fe2O3 和 Fe3O4。 通过 SEM 对锈层截面形貌进行观察发现，在腐蚀初期，耐候钢的锈层厚度较薄仅为 41 μm 且增长较慢，而对比钢 Q345B 的锈层较厚为 75 μm 且疏松。 通过SEM 对锈层进一步进行面扫描分析，对比钢 Q345B 基体及腐蚀产物中的铜(Cu)、铬(Cr)、镍(Ni)等耐腐蚀元素含量较低且未出现富集现象， 而耐候钢基体中检测到一定量的耐腐蚀元素并存在不同程度的富集。 由于耐候钢锈层中富集的Cu、Cr、Ni 等合金元素能够有效阻挡腐蚀介质的渗透，对钢基体腐蚀起到了抑制作用，因此耐候钢比对比钢 Q345B 的耐腐蚀性更好。

In the process of use, corrosion behavior is an important link that restricts the service life and safety of structural steel, among which atmospheric corrosion has a significant impact. To analyse the atmospheric corrosion behavior of structural steel in detail, accelerated corrosion experiments were conducted using a NaHSO3 solution to simulate industrial atmospheric conditions, and the corrosion behavior of the Q345B steel and weathering steel was studied. The weight loss due to corrosion was analysed, and the corrosion rate was calculated. After 168 h of corrosion, the weight loss rate of the Q345B steel is 2.25 g/(m2·h), whereas that of the weathering steel is only 1.74 g/(m2·h). Thus, the corrosion rate of the Q345B steel is higher than that of the weathering steel. X-ray diffraction analysis was used to determine the composition of the corrosion products. The primary corrosion products of both steels are identified as α-FeOOH, γ-FeOOH, Fe2O3,and Fe3O4.SEMobservations of the rust layer cross-sections reveal that initially, the rust layer of weathering steel is thin, approximately 41 μm, and grows slowly, whereas the rust layer of the Q345B steel is thicker, approximately 75 μm, and more porous. SEM analysis of the rust layers reveals that the base metal and corrosion products of the Q345B steel contain low levels of corrosion-resistant elements such as copper (Cu), chromium (Cr), and nickel (Ni), indicating no enrichment. In contrast, weathering steel contains detectable amounts of these elements, which are present to varying degrees. The enrichment of Cu, Cr, and Ni in the weathering steel rust layer effectively blocks the penetration of corrosive media, inhibiting the corrosion of the base metal. Therefore, weathering steel has better corrosion resistance than does Q345B steel.