2 3 20 24 28 16 Inch 1400mm Welded Pre Galvanized Gb3087 Grade 20 1.0308 Carbon Steel Pipe

Galvanized steel tube is divided into cold plating tube, hot plating tube, the former has been banned, the latter is temporarily advocated by the state.

Hot dip galvanized pipe

Hot dip galvanized tube is to make molten metal and iron matrix reaction and produce alloy layer, so that the matrix and coating of the combination of the two. Hot dip galvanizing is the first steel pipe pickling, in order to remove iron oxide on the surface of the steel pipe, pickling, through ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed aqueous solution tank for cleaning, and then into the hot dip plating tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.

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 electric galvanized (cold plating). Only those small, outmoded small businesses use galvanizing, and of course their prices are relatively cheap. The Ministry of Construction has officially below, the elimination of backward technology of cold galvanized pipe, the future is not allowed to use cold galvanized pipe for water, gas pipe.

Hot dip galvanized steel tube: complex physical and chemical reactions occur between the steel tube matrix and the molten plating solution to form a tightly structured zinc-iron alloy layer with corrosion resistance. Alloy layer is integrated with pure zinc layer and steel tube matrix. So its corrosion resistance is strong.

Cold galvanized steel tube: the zinc layer is electric coating, zinc layer and steel tube substrate independent layer. Zinc layer is thin, zinc layer simply attached to the steel tube substrate, easy to fall off. So its corrosion resistance is poor. It is forbidden to use cold galvanized steel pipes as water supply pipes in new residential buildings.