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.

GI pipe typically refers to galvanized iron pipe. Galvanized iron pipe is a steel pipe that has been coated with a layer of zinc to help prevent corrosion. The galvanization process involves applying a protective zinc coating to the steel to provide rust and corrosion resistance, making it suitable for various applications, including plumbing, water distribution, and structural support.

The zinc coating on GI pipes helps to prolong the life of the steel by preventing corrosion caused by exposure to moisture and other environmental factors. GI pipes are commonly used in plumbing installations, particularly for transporting water and other fluids, as well as in construction projects where corrosion resistance is essential.