Galvanized seamless steel pipe
Short Description:
The amount of galvanized seamless steel pipe is very small, only 10-50g / m2, and its corrosion resistance is much different from that of hot-dip galvanized pipe. Regular galvanized pipe manufacturers are allowed to use cold galvanized pipes as water and gas pipes. The galvanized layer of cold galvanized steel pipe is an electroplating layer, and the zinc layer is separated from the steel pipe substrate. 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 steel pipes.
After pickling, API seamless steel pipes are cleaned in ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed aqueous solution tank. In order to ensure quality, electro galvanizing (cold plating) is mostly not used. 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, which will not be electro galvanized in the future. It is to make the molten metal react with the iron matrix to produce an alloy layer, so as to combine the matrix and the coating. Hot dip galvanizing is to pickle the steel pipe first, in order to remove the iron oxide on the surface of the steel pipe, and then send it to the hot dip galvanizing tank. Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.
