Q235钢在广东省输电杆塔现场的大气腐蚀行为

Atmospheric Corrosion Behavior of Q235 Steel Exposed on Transmission Tower Sites of Guangdong Province

基于广东省输电线路分布情况,在城市、工业、海洋和乡村4种环境中选取有代表性的10条杆塔线路,通过1年的现场暴露实验研究了杆塔用Q235钢的大气腐蚀行为,在6、12个月时各取样一次;利用失重法测量各挂片的单位面积腐蚀失重,研究了不同环境中的腐蚀失重规律,并采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对腐蚀产物结构和微观形貌进行表征.结果表明:广东省大气腐蚀等级主要为C3,其次为C2,属于中度腐蚀;不同特征的环境对大气腐蚀的影响从重到轻依次为重工业、海洋+轻工业复合、海洋和特大城市、中小型城市及乡村;在12个月的试验周期内,Q235钢前6个月的腐蚀速率明显高于后6个月;腐蚀产物主要为花瓣网状和细针状结构的α-FeOOH和γ-FeOOH,在海洋环境中还出现少量β-FeOOH.

The atmospheric corrosion behavior of Q235 steel used as the transmission tower material was investigated systematically in the 10 representative transmission lines of four typical atmospheric environments(urban,industrial,marine and rural)by field exposure in Guangdong Province for one year.The period for recapturing samples from the field station lasted 6 and 12 months respectively.Their corrosion weight losses in unit area were mea-sured to investigate the corrosion rule of Q235 steel.X-ray diffraction(XRD)and scanning electron microscopy(SEM)were applied to analyze the microstructure and morphology of the corrosion products respectively.Results suggested that the atmospheric corrosion grade of a large part of Guangdong Province belongs to C3 and other parts belong to C2,a moderate rank as a whole.The influence of different environments on the atmospheric corrosion is different as follows:the heavy industrial environment,the compound one of marine and light industry,the marine and urban one,the little city and rural one.The corrosion rate of Q235 in the previous 6 months is obviously higher than that in the latter stage from 6 to 12 months in one-year-field exposure.The corrosion products are mainlyα-FeOOH andγ-FeOOH with net-or needle-like micro morphology,and a small amount ofβ-FeOOH is observed in the marine environment.