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Characteristics, use and weight coefficient of hot dip galvanized pipe

Hot dip galvanized pipe is made of molten metal and iron matrix reaction to produce alloy layer, so that the matrix and the coating of the two combination. Hot dip galvanizing is to first pickling the steel pipe. In order to remove the iron oxide on the surface of the steel pipe, after pickling, it is cleaned by ammonium chloride or zinc chloride aqueous solution or mixed aqueous solution of ammonium chloride and zinc chloride, and then sent into the hot dip plating tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. Complex physical and chemical reactions occur between the steel tube substrate and the molten bath to form a compact zinc-iron alloy layer with corrosion resistance. The alloy layer is integrated with the pure zinc layer and the steel tube matrix. Therefore, its corrosion resistance is strong.

1. Uniformity of galvanized layer: steel tube sample shall not turn red (copper plating color) after 5 consecutive impregnations in copper sulfate solution.

2, surface quality: the surface of galvanized steel pipe should be complete galvanized layer, there should be no black spots and bubbles on the plating, allowing a small rough surface and local zinc tumor.

3, galvanized layer weight: according to the requirements of the customer, galvanized steel pipe can be measured zinc layer weight, its average should not be less than 500g/ square meter, including any sample should not be less than 480g/ square meter.


The iron pipe used in gas, greenhouse and heating is also galvanized pipe. Galvanized pipe, as a water pipe, produces a large amount of rust and scale in the pipe. The yellow water flowing out not only pollues sanitary ware, but also contains bacteria bred on the unclean inner wall. In the 1960s and 1970s, developed countries began to develop new types of pipes, and have banned galvanized pipes. China's Ministry of Construction and other four ministries and commissions also issued a document to prohibit galvanized pipes from 2000. Galvanized pipes are rarely used in cold water pipes of new residential areas, and some residential hot water pipes use galvanized pipes.

Weight coefficient

Nominal wall thickness: mm2.0, 2.5, 2.8, 3.2, 3.5, 3.8, 4.0, 4.5;

Coefficient: c1.064, 1.051, 1.045, 1.040, 1.036, 1.034, 1.032, 1.028.

Note: The mechanical property of steel is an important index to ensure the final serviceability (mechanical property) of steel, which depends on the chemical composition and heat treatment system of steel. In the steel pipe standard, according to different use requirements, the tensile properties (tensile strength, yield strength or yield point, elongation) and hardness, toughness indicators, as well as user requirements of high, low temperature performance. Grade of galvanized pipe steel: Q215A; Q215B; Q235A; Q235B

Test pressure value /Mpa: D10.2-168.3mm for 3Mpa; The D177.8-323.9mm is 5Mpa.


Zhishang Steel Co., Ltd

ABOUT USOverviewThe company mainly deals in color-coated, galvanized, stainless steel pipes, stainless steel coils, stainless steel plates of various materials; hot-rolled series of rebar, medium and heavy plates, coils, I-beams, angle steels, channel steels, H-beams and other steel products and deep processing Service. (The company’s annual invent···

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