Cold tube plating, hot dip galvanized steel pipe points, the former has been disabled, the latter was the state advocates can use.

Hot dip galvanized pipe

Hot dip galvanized pipe is the molten metal and iron substrate reaction and produce alloy layer, so that the substrate and coating combination of both. Is hot dip galvanized steel pipes to pickling, in order to remove iron oxide on the surface of the steel tube after acid cleaning, by ammonium chloride or zinc chloride or ammonium chloride and zinc chloride mixed aqueous solution tank cleaning, and then sent to the hot dip plating tank. Hot dip galvanized with uniform coating, strong adhesion, long service life, etc. Steel substrate with molten electrolyte solution in complex physical and chemical reaction, the formation of corrosion resistance of the structure compact zinc alloy layer. Pure zinc alloy layer and layer and steel substrate. So the corrosion resistant ability.

1, the uniformity of the galvanized layer: steel pipe sample in copper sulfate solution dipping 5 consecutive shall not become red color (copper)

2, the surface quality: the surface of galvanized steel pipe should be complete galvanized layer, can not have not plating on dark spots and bubbles exist, allow there is a little rough surface and local zinc tumor.

3, galvanized layer weight: according to buyer's request, galvanized steel pipe for weight determination of zinc layer, the average should be not less than 500 g/m2, any of these samples should not be less than 480 g/m2.

Cold galvanized pipe

Cold galvanizing is electricity galvanized, galvanized quantity very few, only 10 to 50 g/m2, its corrosion resistance than galvanized pipe vary a lot. Normal galvanized pipe manufacturers, in order to guarantee the quality, most do not use electric galvanized (cold) plating. Only those small and old equipment of small businesses use electric galvanized, of course, their price is relatively cheaper. At present, the ministry of construction has officially below, eliminating backward technology of cold galvanized pipe, the future not be allowed to use cold galvanized pipe for water and gas pipe. The zinc layer is electrodeposited coating, zinc layer and steel substrate layered independently. The zinc layer is thinner, zinc layer attached on the steel substrate, simple easy to fall off. So the poor corrosion resistance. In the new residence, it is prohibited to use cold galvanization steel tube as a feed pipe.

use

Now gas, greenhouses, heating using the iron pipe and galvanized pipe, galvanized pipe as the pipe, tube to produce large amounts of rust scale, outflow of including not only pollute the clean is provided, and mixed with smooth wall not breed bacteria, heavy metal corrosion caused by the water content is too high, cause serious damage to human body health. Sixties and seventies, developed countries in the world began to develop new pipe material, and gradually to disable the galvanized pipe. China ministry of construction and other four ministries and commissions also send civilization to be banned from recovered a year galvanized pipe, the new district of cold water pipe has been rarely used galvanized pipe, some village used hot water pipe is galvanized pipe.

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