Hot dip galvanized pipe
The hot-dip galvanized tube is obtained by reacting a molten metal with an iron matrix to produce an alloy layer, thereby combining the substrate and the plating layer. Hot-dip galvanizing is to pickle the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe, after pickling, it is washed by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then fed. Hot dip plating tank. Hot-dip galvanizing has the advantages of uniform plating, strong adhesion and long service life. Hot-dip galvanized steel pipe base
Complex physical and chemical reactions with the molten bath to form a corrosion-resistant, compact zinc-iron alloy layer. The alloy layer is integrated with the pure zinc layer and the steel pipe base, so it has strong corrosion resistance.
Cold galvanized pipe
The cold-galvanized pipe is electro-galvanized, with a small amount of galvanizing, only 10-50g/m2, and its corrosion resistance is much worse than that of hot-dip galvanized pipe. Regular galvanized pipe manufacturers, in order to ensure quality, most do not use electro-galvanizing (cold plating). Only small companies with small equipment and old equipment use electro-galvanized steel, of course, their prices are relatively cheaper. The Ministry of Construction has officially laid down the cold-galvanized pipe with backward technology and the use of cold-galvanized pipe as water and gas pipe. The galvanized layer of the cold-galvanized steel pipe is an electroplated layer, and the zinc layer and the steel pipe base are separately layered. The zinc layer is thin, and the zinc layer is simply attached to the steel pipe base and is easy to fall off. Therefore, its corrosion resistance is poor. In new homes, the use of cold-galvanized steel pipes as water supply pipes is prohibited.