Study Of Steel Anti-corrosion And Secondary Repair In Power Transmission Steel Structure

At present, in all the factors which affected the durability of the steel structure, thesteel corrosion resistance played a crucial and decisive role. It was directly related tothe entire working life and safety of the project and post-downtime maintenance andother problems. Therefore, to enhance the corrosion resistance of steel and other fieldsof research were particularly important.Two kinds of hot-dip galvanizing specimens from different factories and fourkinds of specimens treated by zinc-rich paints were used for accelerated corrosion tests,the macroscopic phenomena through different periods of the test specimen andmorphology of a combination of factors analysis to study the hot-dip galvanized layerand zinc-rich paint coating of preservative treatment effect and secondary repair effect.The study showed that there were large differences between anti-corrosionproperties of the hot-dip galvanized layer and zinc-rich paint coating. In neutral saltspray test, the anti-corrosion effect of hot-dip galvanized layer was influenced by themicrostructure and by the hot-dip galvanized production and layer thickness and otherfactors. In addition, anti-corrosion effect of zinc-rich paint coating were influenced bythe zinc content of the coating dry film and the purity zinc powder, zinc powderparticles, the condition of zinc powder dispersed in the coating. In the acid salt spraytest, the hot-dip galvanized layer and the zinc-rich paint coating rendered more fastercorrosive because the presence of acid made the layer and coating of zinc to be moresusceptible to be consumed through the chemical reaction, which resulted in theelectrochemical reaction continuing and reducing the shielding effect of the layer andcoating. In addition, the study also showed that the layer and coating of zinc tended tobubbling and peeling, so that the rapid loss of coating of anticorrosion performance. Study of secondary repair of steel coating effect showed that coating and layerwere good compatible. Neutral salt spray corrosion test did not appear in the process ofthe bubbling, cracking, peeling. Not only could secondary repair thoroughly solve theproblem of the surface corrosion, but also could enhance the anticorrosion ability ofthe steel substrate components, and be convenient for operation. Secondary repair ofanticorrosive coating was carried out before large areas of corrosion in hot dipgalvanizing layer and complete loss of hot dipping zinc layer thickness.