模拟酸雨大气环境下Q420B高强钢角钢的腐蚀疲劳性能试验研究

目前,高强钢在建筑结构中逐渐得到广泛应用,而其耐候性和疲劳性能对结构安全影响较大。对于长期暴露在野外大气环境中的结构,如输电铁塔,因长期受风致振动和大气环境中酸雨腐蚀的耦合作用,易发生腐蚀疲劳破坏甚至倒塌,所以研究酸雨大气环境下高强钢(如输电塔常用钢Q420B)的腐蚀疲劳性能具有重要意义。为此,对43根Q420B等边角钢在模拟酸雨大气作用下的腐蚀疲劳性能进行了研究,并基于简化的单点-似然法及单点-成组法拟合了其应力-疲劳寿命(Δσ-N)曲线和不同保证率p下的p-Δσ-N曲面。研究结果表明:酸雨大气环境缩短了Q420B角钢在中低荷载水平下对应的中长期疲劳寿命,而对高荷载水平下对应的短期疲劳寿命影响不大;环境因素对角钢的腐蚀疲劳性能有显著的影响,在模拟试验中,腐蚀液的pH值越低,间隔喷雾时间越长,相同荷载下角钢的腐蚀疲劳寿命越短。

Experimental study on corrosion fatigue behavior of Q420Bangle in simulated acid rain atmospheric environment

Nowadays high strength steel has been widely used in structures, and its durability and fatigue performance can greatly affect the safety of the structures. When exposed to environmental atmosphere, structures such as transmission towels are subjected to the coupling effect of the acid rain environment and wind-induced vibration, and are therefore susceptible to corrosion fatigue damages or even collapse risk. In light of this, it is important to study the corrosion fatigue performance of high strength steels (such as Q420B which is widely used in transmission towels) in the acid rain atmospheric environment. In this study, the corrosion-fatigue performances of 43 equal angles in the simulated acid rain atmospheric environment were studied, and their stress-fatigue life(Δσ-N) curves and p-Δσ-N surfaces with different guarantee ratios p were obtained by the simplified single point likelihood method and the simplified single-point group method. It is concluded that the acid rain atmospheric environment can dramatically shorten the medium-term and long-term fatigue lives of the angle steels under medium or low load level, while the influence is slight on the short-term fatigue lives under high load level. The environmental parameters have a significant influence on the corrosion-fatigue performances of the angle, and the fatigue lives of the angle under the same load decrease with decreasing pH values of the erosion solution, and decrease with increasing time interval of spray in the simulated experiment.