目的 研究 Q235 钢在海洋大气环境中的耐蚀性能,分析近海环境下 Q235 钢的腐蚀机理。 方法采用盐雾试验、恒温恒湿试验等,模拟海洋大气环境,研究不同温度、相对湿度、氯离子含量下 Q235 钢的腐蚀规律,并利用表观腐蚀形貌分析、金相分析及 XRD 等技术手段,分析对应的腐蚀形貌和腐蚀产物。结果 模拟海洋大气环境下,Q235 钢腐蚀速率随温度升高而增加。 随着氯离子含量增加,Q235 钢腐蚀速率先增加后减小,当 NaCl 质量分数为 1. 75% 时,其腐蚀速率最大。 相对湿度增大可以加速 Q235 钢腐蚀,相对湿度大于 85% 后,其腐蚀速率急剧增大。 盐雾环境下,Q235 钢的腐蚀类型为点蚀,主要腐蚀产物为 Fe2O3 和 Fe3O4。 结论 海洋大气环境下,温度、相对湿度、氯离子含量均为 Q235 钢腐蚀的重要影响因素,腐蚀危害表现为点蚀穿孔,需要采取表面防护措施。

Objective To investigate the corrosion-resisting function of the Q235 steel in the ocean air atmosphere, and figure out the corrosion mechanism of the Q235 steel in the offshore environment. Methods Salt spray test and constant temperature and humidity test were used to study the corrosion rules of the Q235 steel at different temperatures, relative humidifies and chloride ion contents in simulated ocean air atmosphere. Surface corrosion morphology analysis, metallographic analysis and XRD component analysis were used to analyze the respective corrosion morphology and corrosion products. Results With increasing temperature, the corrosion rate of Q235 steel under the simulated ocean air environment was raised. With increasing chloride ion concentration, the corrosion rate was elevated in the initial stage and peaked when the chloride ion concentration was 1. 75% , after which the corrosion rate started to decrease. With increasing relative humidity, the corrosion rate of Q235 steel was accelerated, especially when the relative humidity was larger than 85% . In addition, in the salt spray environment, the corrosion manifestation of Q235 steel was pitting corrosion and the major corrosion products were Fe2O3 and Fe3O4. Conclusion Under the ocean air atmosphere, temperature, humidity and chloride ion content are all important factors that can lead to severe corrosion of the Q235 steel, and the major corrosion manifestation is pitting perforation. Therefore, surface protection measures for Q235 steel must be taken.