There are many causes of corrosion of steel structure. In terms of environment, long-term exposure of steel structures to relatively humid environment should be avoided, and the corrosion of steel structures will be accelerated by chemical substances such as acid and salt in the environment; secondly, unreasonable design, for example, the distance between steel frames and walls is too close; during construction, corrosion will also occur due to the imprecise quality control of coatings and inspection of film thickness. Corrosion and rusting of steel structures are very harmful, which will not only reduce the strength and load-bearing capacity of steel structures, but also cause deformation, fracture and collapse of steel structures due to corrosion. Once the accident occurs, it will cause huge losses.
Therefore, good anti-corrosion work is an important work of steel structure building, anti-corrosion coatings can be selected to prevent corrosion of steel structure. From the aspects of anticorrosion life, light and colour retention, and maintenance convenience, a long-term anticorrosive coating with total film thickness not less than 150 micron should be adopted for outdoor steel structures. Iron red alkyd primer, mica alkyd antirust paint and alkyd topcoat should be used for indoor steel structure. The total thickness of the paint film is 160 um.