国内外耐候钢腐蚀疲劳试验技术发展

为了解耐候钢在腐蚀作用下的疲劳性能,并更好地用于桥梁建设,腐蚀疲劳试验是有效的研究途径.首先,介绍了环境腐蚀等级分类、均匀腐蚀和坑蚀,简述了腐蚀作用对钢材及其疲劳性能的影响.随后,回顾了3种疲劳试验的种类,总结和分析了国内外腐蚀作用对疲劳性能影响的试验研究结果.在此基础上,归纳了腐蚀疲劳试验包含的内容:试件设计、腐蚀试验和疲劳试验,研究了耐候钢腐蚀疲劳试验.最后,进行了20个加速腐蚀后HPS 485W和Q345CNH钢的疲劳试验,并与自然腐蚀后的耐候钢进行对比分析.结果表明:腐蚀环境能对钢材的腐蚀作用产生很大影响,坑蚀作用是导致疲劳裂纹萌生的重要因素;虽然有多种钢材的腐蚀疲劳试验方法,但需要有顺序有层次合理地展开相关试验研究;试件的设计应该在规范的基础上进行优化,并考虑疲劳过程中试件的能量耗散;在加速腐蚀试验需要合理控制环境条件,保证预期的试验结果;盐雾干/湿交替腐蚀后耐候钢的疲劳强度大幅降低,并且数据离散性更小.在自然腐蚀试验和加速腐蚀试验结合的基础上,逐步实现从腐蚀后疲劳试验到腐蚀-疲劳试验和从小试件到结构件的发展.

Development of domestic and international corrosion fatigue test technologies for weathering steel

To improve the application of weathering steel in bridge constructions, corrosion fatigue test can be adopted as an effective approach to investigate its fatigue performance under corrosion. First, the classification of the corrosivity of environment, uniform corrosion, and pitting corrosion were introduced, and the effects of corrosion on the fatigue performance of steel were briefly described. Next, three typical types of fatigue tests were reviewed, and results of both domestic and international studies were summarized and analyzed. Then, the content of corrosion fatigue test was summarized, including design of steel specimens, corrosion test methods, and fatigue test methods. Finally, a series of fatigue tests were carried out on 20 corroded HPS 485W and Q345CNH steel specimens, and results were compared with naturally corroded weathering steel specimens. Results indicate that corrosion environment can greatly influence the corrosion of steel, in which the pitting corrosion is a critical factor that can induce the initiation of fatigue cracks. Meanwhile, relevant experimental studies need to be carried out orderly and hierarchically although there are many different kinds of corrosion fatigue test methods. Besides, the design optimization of specimens should be made based on the related codes, and it is critical to take into account of the excessive energy dissipation of specimens during fatigue tests. In experiment process, a reasonable control of corrosion environment conditions is crucial to guarantee the expected test results. It is worth noting that the fatigue strength of the weathering steel specimens decreased significantly after the salty spraying dry/wet corrosion test, and the scatter in data was notably reduced compared with those of uncorroded specimens. Based on the combination of natural corrosion test and accelerated corrosion test, the progresses from weathering fatigue test to corrosion-fatigue test and from small specimen to structural specimen can be gradually realized.