Q235和Q450钢在吐鲁番干热大气环境中长周期暴晒时的腐蚀行为研究

Corrosion Behavior of Carbon Steels Q235 and Q450 in Dry Hot Atmosphere at Turpan District for Four Years

在吐鲁番干热大气环境中对Q235和Q450钢进行4 a大气暴晒实验。结果表明,两种钢表面均有较为明显的锈层,Q450耐候钢4 a的平均腐蚀速率为12 g·m^(-2)·a^(-1),Q235钢平均腐蚀速率为14 g·m^(-2)·a^(-1),Q450钢腐蚀速率相对较低,腐蚀坑深度较浅。腐蚀产物主要由α-FeOOH,γ-FeOOH和Fe_2O_3·H_2O组成,其中Q450钢腐蚀产物中α-FeOOH比例相对较高,腐蚀产物致密。电化学阻抗测试结果表明:Q450钢腐蚀产物电阻远大于Q235钢的,表面电荷转移电阻也大于Q235钢的,即Q450钢耐蚀性较好,腐蚀产物对基体保护作用相对较好。

Atmospheric exposure of carbon steels Q235 and Q450 were conducted for 4 a in dry hot atmospheric environment at Turpan district of Xinjiang Uygur Autonomous Region. The results showed that the surface of the two steels presented obvious corrosion products scale. The average corrosion rate of Q450 and Q235 was 12 and 14 g·m^（-2）·a^（-1） respectively. Thus, Q450 steel exhibits corrosion rate lower than Q235 steel, and while the corresponding corrosion pits were relatively shallow. The corrosion products of the two steels composed mainly of α-FeOOH, γ-FeOOH and Fe2O3·H2O, while the proportion of α-FeOOH for Q450 was higher than that for Q235. The corrosion products on Q450 were relatively dense. Thereby, it hindered the absorption of water and sediment, leading to the decrease of corrosion rate. The result of EIS demonstrated that the resistance of corrosion products and surface charge transfer of Q450 was greater than that of Q235, i.e. the corrosion products of Q450 had better protectiveness.