Galvanized welded pipe
Short Description:
In order to improve the corrosion resistance of steel pipes, general steel pipes are galvanized. Galvanized steel pipes are divided into hot-dip galvanizing and electro galvanizing. The hot-dip galvanizing layer is thick, the cost of electro galvanizing is low, and the surface is not very smooth. Oxygen blowing welded pipe: it is used as steel blowing pipe. Generally, small-diameter welded steel pipe is used, with eight specifications of 3 / 8-2 inches. It is made of 08, 10, 15, 20 or 195-q235 steel strip. In order to prevent corrosion, aluminizing treatment must be carried out.
Classification of galvanized pipes
Galvanized steel pipe is divided into cold plating pipe and hot plating pipe. The former has been banned and the latter has been advocated by the state for temporary use
Hot dip galvanized pipe
Hot dip galvanized pipe is to make molten metal react with iron matrix to produce alloy layer, so as to combine the matrix and coating. Hot dip galvanizing is to pickle the steel pipe first. In order to remove iron oxide on the surface of the steel pipe, after pickling, it is cleaned in ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed aqueous solution tank, and then sent to the hot dip galvanizing tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.
Cold galvanized pipe
Cold galvanizing is electro galvanizing. The amount of galvanizing is very small, only 10-50g / m2. Its corrosion resistance is much different from that of hot-dip galvanized pipe. In order to ensure the quality, most regular galvanized pipe manufacturers do not use electro galvanizing (cold plating). Only those small enterprises with small scale and old equipment use electro galvanizing, of course, their price is relatively cheap. The Ministry of construction has officially eliminated the backward cold galvanized pipe, and it is not allowed to use the cold galvanized pipe as water and gas pipe in the future.
Hot dip galvanized steel pipe: the steel pipe matrix reacts with the molten plating solution to form a corrosion-resistant zinc ferroalloy layer with compact structure. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix. Therefore, it has strong corrosion resistance.
Cold galvanized steel pipe: the zinc layer is an electroplating layer, and the zinc layer is separated from the steel pipe matrix. The zinc layer is thin, and the zinc layer is simply attached to the steel pipe matrix, which is easy to fall off. Therefore, its corrosion resistance is poor. In new houses, it is forbidden to use cold galvanized steel pipes as water supply pipes.
