Hot-dip galvanized steel pipe is to make the molten metal react with the iron matrix to form an alloy layer, so that the matrix and the coating are combined. Hot-dip galvanized steel pipes are pickled to remove iron oxide on the surface of the steel pipes. After pickling, they are cleaned by ammonium chloride or zinc chloride solution or mixed solution tanks of ammonium chloride and zinc chloride, and then enter the hot Dip. Take a bath. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.
Cold galvanizing is electro-galvanizing, and the amount of galvanizing is very small, as long as 10-50g/m2, its own corrosion resistance is much worse than that of hot-dip galvanized pipe. Most of the regular galvanized pipe manufacturers do not choose electro-galvanized (cold plating) in order to ensure quality. As long as small enterprises with small planning and outdated equipment choose electro-galvanizing, of course their prices are relatively cheaper. The Ministry of Construction has officially announced that it will screen out cold-galvanized pipes with outdated technology and prohibit the use of cold-galvanized pipes as water and gas pipes.
Generally, the galvanized steel pipes used today are hot-dip galvanized, while the electrical trunking is cold-dip galvanized, and the color is different. The cold-dip galvanizing is only on the outer tube wall, and the hot-dip surface is galvanized. , The galvanized welded pipe is hot-dip galvanized on the basis of the welded steel pipe (that is, the zinc is melted in the zinc pot, and the steel pipe is immersed in the liquid zinc for a period of time, and then cooled and dried). A zinc layer is attached to the inner and outer walls of the steel pipe. Galvanized pipes are generally used for the transportation of low-pressure fluids (ie water, liquid gas).
