Quality Inspection for Cold Drawn Seamless - Galvanezed Seamless Steel Pipe – XUANZE

Galvanized seamless steel pipe is hot-dip galvanized, so the amount of zinc plating is very high, the average thickness of zinc coating is more than 65 microns, and its corrosion resistance is much different than that of hot-dip galvanized pipe. The regular galvanized pipe manufacturer can use cold galvanized pipe as water and gas pipe. The zinc coating of cold galvanized steel pipe is electroplated layer, and the zinc layer is separated from the steel pipe substrate. The zinc layer is thin and easy to fall off because it is attached to the steel pipe substrate. Therefore, its corrosion resistance is poor. It is forbidden to use cold galvanized steel pipe as water supply steel pipe in new residential buildings.

Galvanized steel pipe is widely used in construction, machinery, coal mine, chemical industry, electric power, railway vehicles, automobile industry, highway, bridge, container, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery and other manufacturing industries.

Hot dip galvanized steel pipe: hot dip galvanized pipe is to make molten metal react with iron matrix to produce alloy layer, so that the matrix and coating are combined. In order to remove iron oxide on the surface of steel pipe, after pickling, the steel pipe is cleaned by ammonium chloride or zinc chloride aqueous solution or mixed solution tank of ammonium chloride and zinc chloride, and then sent to hot-dip galvanizing tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The complex physical and chemical reactions between the substrate of hot-dip galvanized steel pipe and the molten bath lead to the formation of a zinc ferroalloy layer with a compact corrosion resistance structure. The alloy layer is integrated with pure zinc layer and steel pipe matrix, so its corrosion resistance is strong.

Cold galvanized steel pipe: cold galvanized pipe is electro galvanized, the amount of zinc plating is only 10-50g / m2, and its corrosion resistance is much different from that of hot-dip galvanized pipe. In order to ensure the quality, most of the regular galvanized pipe manufacturers do not use electro galvanizing (cold plating). Only those small-scale, old equipment of small enterprises to use galvanizing, of course, their prices are relatively cheap. The Ministry of construction has officially announced the elimination of backward cold galvanized pipes, and it is not allowed to use cold galvanized pipes as water and gas pipes. The zinc coating of cold galvanized steel pipe is electroplated layer, and the zinc layer is separated from the steel pipe substrate. The zinc layer is thin and easy to fall off because it is attached to the steel pipe substrate. Therefore, its corrosion resistance is poor. It is forbidden to use cold galvanized steel pipe as water supply pipe in new residential buildings.

GALVANIZED SEAMLESS STEEL PIPE

Acid washing

Remove iron oxide on the surface of steel parts

Zinc chloride + Ammonium chloride

Wash in the mixed aqueous solution tank.

Hot dip plating

Hot-dip galvanized

Strong corrosion resistance.

The coating is uniform.

Strong adhesion.

 Long lasting.

SIZE:

Wear resisting  Self lubrication   High chemical sability   Various size and type

Spiral wire interface

Spiral wire coupling

APPLICATION

Bridge

Mechanical engineering