〣Product description

Hot-dip galvanized pipe, in order to improve the corrosion resistance of steel pipe, the general steel pipe is galvanized. Galvanized steel pipe is divided into hot dip galvanized and electric galvanized. The layer of hot dip galvanized is thick, the cost of electric galvanized is low, and the surface is not very smooth.

〣Classification of galvanized pipe

Galvanized steel pipe is divided into cold galvanized pipe and hot galvanized pipe. The former has been banned, and the latter is also advocated by the state.

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.

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 galvanizing (cold plating). Only small businesses with obsolete equipment use galvanizing, and of course their prices are relatively cheap. The Ministry of Construction has officially announced the elimination of cold galvanized pipes with backward technology, and it is not allowed to use cold galvanized pipes as water and gas pipes in the future. The zinc layer is an electric coating, and the zinc layer is layered independently with the steel tube substrate. Zinc layer is thin, zinc layer is simply attached to the steel tube matrix, easy to fall off. So its corrosion resistance is poor. It is prohibited to use cold galvanized steel pipes as water supply pipes in newly built houses.

〣Product parameter