The molten metal reacts with the iron matrix to produce an alloy layer, so that the matrix and the coating are combined. Hot dip galvanizing is to acid the steel pipe first in order to remove the iron oxide on the surface of the steel pipe, after pickling,through chlorination or zinc chloride aqueous solution or chlorination and zinc chloride mixed aqueous solution tank washing,cleaning, and then into the hot dip plating tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.
2. Cold galvanized pipe
Cold galvanized is electric galvanized, galvanized amount is very small, only 10-50g/m2, its own corrosion resistance is much different than hot galvanized pipe. Regular galvanized pipe manufacturers, in order to ensure quality, most do not use galvanizing (cold plating). Only small businesses with outdated equipment use electric zinc, and they are relatively cheap. At present, the Ministry of Construction has formally below, eliminate the backward technology of cold galvanized pipe, the future is not allowed to use cold galvanized pipe as water, gas pipe
3. Hot dip galvanized steel pipe
Complex physical and chemical reactions occur between the steel tube substrate 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. Therefore, its corrosion resistance is strong.

Galvanized pipe function:
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. Welded steel pipes with hot dip or electrogalvanizing coating on the surface of degree zinc steel pipes. Galvanized steel pipe can increase the corrosion resistance, prolong the service life. Galvanized pipe has a wide range of uses, in addition to the pipeline pipe for water, gas, oil and other general low pressure fluid, but also used in the petroleum industry, especially the oil well pipe, oil pipeline, chemical coking equipment of the oil heater, condensate cooler, coal distillation and washing oil exchanger with the pipe, and trestle pipe pile, mine tunnel support frame with pipe.