November 16, 2022
1. What is galvanized steel pipe
Galvanized steel pipes are divided into cold galvanized pipes and hot-dip galvanized pipes. At first, galvanized steel pipes were used as water pipes. After a few years, a large amount of rust was generated in the pipes. The outflowing yellow water not only polluted sanitary ware, but also mixed with bacteria that breed on the unsmooth inner wall. , The rust causes the heavy metal content in the water to be too high, which seriously endangers human health. Therefore, in the 1960s and 1970s, developed countries began to develop new types of pipes and gradually banned galvanized steel pipes.
Hot-dip galvanized steel pipe is an alloy layer produced by the reaction of molten metal and iron matrix, so that the matrix and the coating are combined. Hot-dip galvanizing is to first pickle the steel pipe to remove iron oxide on the surface of the steel pipe. After pickling, it is sent to the tank of ammonium chloride or zinc chloride aqueous solution or mixed aqueous solution of ammonium chloride and zinc chloride for cleaning, and then sent to the tank. in the hot dip bath. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. The hot-dip galvanized steel pipe substrate undergoes complex physical and chemical reactions with the molten bath to form a corrosion-resistant and tightly structured zinc-iron alloy layer. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix, and its corrosion resistance is strong.
Cold galvanized steel pipe is electro-galvanized. The amount of galvanized is very small, only 10-50g/m2. Its corrosion resistance is much worse than that of hot-dip galvanized steel pipe. In order to ensure quality, regular galvanized pipe manufacturers generally do not use electro-galvanizing, only those small enterprises with small scale and outdated equipment will use electro-galvanizing, and their prices are naturally relatively cheap. The galvanized layer of the cold galvanized steel pipe is an electroplating layer, and the zinc layer is independently layered with the steel pipe substrate. The zinc layer is thin, and it is simply attached to the steel pipe substrate, which is easy to fall off, and its corrosion resistance is poor.
2. Application of galvanized steel pipe
Galvanized steel pipe is a welded steel pipe with hot-dip galvanized or electro-galvanized coating on the surface. Galvanizing can increase the corrosion resistance of steel pipes and prolong the service life. Galvanized steel pipes are widely used. In addition to being used as pipeline pipes for general low-pressure fluids such as water, gas, and oil, they are also used as oil well pipes and oil pipes in the petroleum industry, especially in offshore oil fields, oil heaters in chemical coking equipment, and condensation cooling. Pipes for septic tank, coal distillation washing oil exchanger, trestle pipe piles, supporting frame pipes for mine tunnels, etc. Hot-dip galvanized strip steel pipes are widely used in various modern manufacturing industries.
