The hot-dip galvanized steel pipe is to make the molten metal react with the iron substrate to produce an alloy layer, then combining the substrate and the plating layer. Hot-dip galvanizing is to pickle the steel pipe first, to remove the iron oxide on the surface of the steel pipe, wash through the ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed aqueous solution tank after pickling, and then put into hot dip plating bath. Its advantage is uniform coating, strong adhesion and long service life.

The cold galvanized is electro-galvanized, the amount of galvanized is very small, only 10-50g / m2, its corrosion resistance is worser than hot galvanized pipe. Most big pipe manufacturers, in order to ensure quality, do not use electro-galvanized (cold plating). The Ministry of Construction has officially announced the elimination of cold-dip galvanized pipes with backward technology, and it is forbidden to use cold-dip galvanized pipes for water and gas pipes.

Generally, galvanized steel pipes are means hot-dip galvanized steel pipe, and the wire grooves used in electrical are cold-dip galvanized steel pipe, and they are different in color.

Cold plating --- external plating

Hot plating --- internal and external plating

The galvanized welded steel pipe is hot galvanized on the basis of the welded steel pipe (the zinc is dissolved in the zinc pot, then the steel pipe is immersed in liquid zinc for a period of time, and then cooled and blown dry). Galvanized pipes are generally used for the transportation of low-pressure fluids (i.e. water, liquid gas).

Galvanized steel pipe price calculation formula

Different wall thicknesses have different prices: 1 meter price = 3.14 [(D / 2) * 2- (d / 2) * 2] x1000mmx7.8x10-6 kg / mm * 3x5.7 yuan / kg

D is the outer diameter of the pipe

d is the inner diameter of the pipe