Hot-dip galvanizing pipe is to make the molten metal and iron matrix reaction layer, resulting in both the substrate and the combination of coating. Hot dip galvanized steel pipe is the first pickling, in order to remove the surface of iron oxide steel, pickled, ammonium chloride or zinc chloride or ammonium chloride or zinc chloride aqueous solution mixed with water tank cleaning, and then into Hot-dip plating bath.
Hot dip galvanized with uniform coating, strong adhesion, long life and other advantages. Cold galvanizing is the electro-galvanized, galvanized very small, only 10-50g / m2, its own corrosion resistance than hot galvanized pipe a lot worse. Regular galvanized pipe manufacturer, in order to ensure quality, most do not use electro-galvanized (cold plating). Only those small, outdated small businesses using electro-galvanized, of course, their prices are relatively cheaper.
The Ministry of Construction has been officially below, out of backward technology galvanized pipe cold, .cold galvanized pipe in the future are not allowed to make water, gas pipe Hot-dip galvanized steel pipe: the base of the steel pipe and the molten bath complex physical and chemical reactions, the formation of corrosion-resistant structure of a close zinc-iron alloy layer. Alloy layer and pure zinc layer, steel tube matrix integration. So its strong corrosion resistance. Cold galvanized steel pipe: zinc layer is the electroplating layer, the zinc layer and the steel pipe matrix independent delamination. The zinc layer is thin, and the zinc layer is simply attached to the steel tube substrate, and is easily peeled off. So its poor corrosion resistance. In the new residential, the prohibition of the use of cold galvanized steel pipe as a water pipe
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