Hot-dip galvanized steel pipes are widely used in construction, machinery, coal mines, chemicals, electricity, railway vehicles, automobile industry, highways, bridges, containers, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery, greenhouse construction and other manufacturing industries. Galvanized steel pipes are welded steel pipes with hot-dip or electrogalvanized layers on the surface. Galvanizing can increase the corrosion resistance of steel pipes and extend their service life. Galvanized Pipes are widely used. In addition to being pipelines for general low-pressure fluids such as water, gas, and oil, they are also used as oil well pipes and oil pipelines in the petroleum industry, especially marine oil fields, oil heaters, condensation coolers, and pipes for coal distillation oil washing exchangers for chemical coking equipment, as well as pipes for trest pipe piles and support frame pipes for mining tunnels. Detailed introduction and editing hot-dip galvanized pipes Hot-dip galvanized pipes react molten metal with iron matrix to produce an alloy layer, thereby combining the substrate and the plating layer. Hot-dip galvanizing means that the steel pipe is first pickled. In order to remove iron oxide on the surface of the steel pipe, after pickling, it is cleaned by ammonium chloride or aqueous zinc chloride solution or a mixed aqueous solution tank of ammonium chloride and zinc chloride, and then sent to the hot-dip plating tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The hot-dip galvanized steel pipe matrix undergoes complex physical and chemical reactions with the molten plating solution, forming a zinc-iron alloy layer with a corrosion-resistant structure. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix, so it has strong corrosion resistance. Cold galvanized pipes Cold galvanized pipes are electro-galvanized, with very little galvanized galvanized amounts, only 10-50g/m2, and their corrosion resistance is much different from that of hot-dip galvanized pipes. For regular galvanized pipe manufacturers, in order to ensure quality, most of them do not use electro-galvanized (cold plating). Only small businesses with small scale and outdated equipment use electrogalvanized galvanization, and of course their prices are relatively cheap. The Ministry of Construction has officially issued a document to eliminate cold galvanized pipes with backward technology, and cold galvanized pipes are not allowed to be used as water and gas pipes. The galvanized layer of cold galvanized steel pipe is an electroplating layer, and the zinc layer and the steel pipe substrate are independently layered. The zinc layer is thin, and the zinc layer is simply attached to the steel pipe substrate and is easy to fall off. Therefore, its corrosion resistance is poor. In newly built residential buildings, cold galvanized steel pipes are prohibited as water supply pipes.
