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,exploration machinery and other manufacturing industries.
Galvanized steel pipes are divided into hot-dip galvanized steel pipes and cold galvanized steel pipes. 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 to form a compact zinc-iron alloy layer with corrosion resistance. The alloy layer is integrated with the pure zinc layer and the steel tube matrix, so its corrosion resistance is strong.
Cold galvanized steel pipe is electric galvanized, galvanized amount is little, cold galvanized steel pipe galvanized layer is electroplating, zinc layer and steel pipe matrix independent stratification. 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.
