Galvanized steel pipe is divided into cold galvanized steel pipe, hot galvanized steel pipe, cold galvanized steel pipe has been banned, the latter is also advocated by the state can be used temporarily.
The galvanized layer of cold galvanized steel pipe is the electroplating layer, and the zinc layer is independently layered with the steel pipe matrix. Zinc layer is thin, zinc layer is simply attached to the steel tube matrix, easy to fall off. So its corrosion resistance is poor. It is prohibited to use cold galvanized steel pipes as water supply pipes in newly built houses.
Hot dip galvanized pipe is made of molten metal and iron matrix reaction to produce alloy layer, so that the matrix and the coating of the two combination. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. Complex physical and chemical reactions occur between the matrix of hot-dip galvanized steel pipe and the molten bath in the spay, and a compact zinc-iron alloy layer with corrosion resistance is formed. The alloy layer is integrated with the pure zinc layer and the steel tube matrix, so its corrosion resistance is strong. Hot-dip galvanized steel pipe is widely used in construction, machinery, coal mine, chemical industry, electric power, railway vehicles, automobile industry, highway, bridge, container, sports facilities, agricultural machinery, petroleum machinery, mining machinery, greenhouse construction and other manufacturing industries.
