Hot-dip galvanized pipes are made by reacting molten metal with a ferrous substrate to create an alloy layer that combines both the substrate and the coating. Hot-dip galvanizing is carried out first by pickling the steel pipe, and in order to remove the iron oxide from the surface of the pipe, the pickling is followed by cleaning in an aqueous solution of ammonium chloride or zinc chloride or a mixture of ammonium chloride and zinc chloride in an aqueous solution tank, which is then fed into the hot-dip galvanizing tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. Hot-dip galvanized steel strip is mainly used in the building materials industry, packaging industry, metal mesh, steel springboards, etc.
