Channel steel is a long strip of steel with a groove-shaped cross-section. It belongs to carbon structural steel for construction and machinery. It is a section steel with a complex section and its cross-section is a groove-shaped. Channel steel is mainly used in building structures, vehicle manufacturing and other industrial structures, and is often used in conjunction with I-beam. Channel steel is more difficult to be corroded by chemical reaction with the medium due to its special metallographic structure and surface passivation film, but it cannot be corroded under any conditions. Channel steel will encounter various problems during use, and corrosion is one of the more important problems. Channel steel corrosion is generally caused by the following two reasons.
1.Chemical corrosion: oil, dust, acid, alkali, salt, etc. attached to the surface of the channel steel are transformed into corrosive media under certain conditions, and chemically react with certain components in the channel steel, resulting in chemical corrosion and rust; The damage to the passivation film caused by scratches reduces the protection ability of the channel steel, and is easy to react with chemical media, resulting in chemical corrosion and rust.
2. Electrochemical corrosion: scratches caused by contact with carbon steel parts and corrosive media form galvanic corrosion; electrochemical corrosion is caused by the adhesion of rusty materials such as cutting slag, splash and corrosive media; The physical defects (undercuts, pores, cracks, lack of fusion, incomplete penetration, etc.) and chemical defects (grain size, segregation, etc.) in the welding area and corrosive media form galvanic cells and produce electrochemical corrosion.
Therefore, all effective measures should be taken during channel steel processing operations to try to avoid rust conditions and inducements. One way is to use spray aluminum coating. The aluminum spray coating and the anticorrosive coating seal can greatly extend the service life of the coating. From the perspective of theory and practical application, the zinc or aluminum spray coating is the ideal bottom layer of the anticorrosive coating; the aluminum spray coating and the steel substrate Strong bonding force, long coating life, good long-term economic benefits; flexible aluminum coating process, suitable for long-term protection of important large-scale and difficult-to-maintain steel structures, and can be constructed on site.