Corrosion Crack Of High Voltage Transmission Towers In The 220kV Of Chuxi Circuitry

The corrosion crack of angle steel sheet of the high voltage transmission tower's framework in the 220kV Chuxi Circuitry was researched. The component of the framework's angle steel sheet was analysed by cutting out powder. The microconstructure of the framework's angle steel sheet was studied by metallographic examination (bright field,dark field and polarized). The inclusion properties of the tower's material and corrosion product were studied by electron probe microanalyner and X-ray diffractometer. The stress state of the zinc coating and the substrate interface was studied by metalloscope and scanning electron microscope. The mechanical property of the framework's angle steel sheet was studied by universal testing machine. The results show that there were double deck cuticle and fold in the material's surface, and there were lots of sulfide and silicate intermittently presented in the material, and there were some interlayer and microcrack in the material. The main chemical element content of carbon and silicon is 0.1% and 0.21% . The material's intensity and plastic were lower than A₃F's. The zinc coating was destroyed and the microcracks is increased as the stress increased. Electrochemistry corrosion resulted in 50% Fe₃O₄ and 50%α-FeO(OH) in the corrosion product.Lots of electrochemistry experiments of Tafel and cyclic voltammetry curve through imitating the different pH value acid rain in the natural environment, different temperature and the stress of specimen were studied. The corrosion characteristics of the Q215 zinc-coated angle steel sheet were investigated under the different pH acid rain, environmental temperature and the stress of specimen. The results indicat that when the surface of Q215 steel plate was coated for defending its corrosion regulation was the same to the zinc-plated steel plate coating material, not relate to the body material. As the temperature raised, the corrosion potential of the sheet decreased and was prone to corrosion. In the solution of acid rain, the corrupting rate of Q215 zinc-plated steel plate was mostly influenced by the temperature, the corrosion rate auelerates with the increasing of temperature. The corrosion rate of the sheet failed at first and then raised by the increasing of pH value under the same temperature; the corrosion rate of the sheet was lowest and the corrosion resistance was best at pH3.2. In the tensile phase of Q215 zinc-plated steel plate, the corrosion speed was rapidly increased with stress increasing.Finally, online eddy detection was developed to find out deficiencies of towers in the early stage.