1. Different production
Galvanized steel pipes are divided into cold dip galvanized steel pipes and hot dip galvanized steel pipes. Cold dip galvanized steel pipes have been banned. In the 1960s and 1970s, developed countries in the world began to develop new types of pipes and gradually banned galvanized tubes.
In order to improve the corrosion resistance of steel pipes, the hot dip galvanized tube is that general steel pipe is galvanized. Galvanized steel pipes are divided into two types: hot dip galvanized tube and electro-galvanized tube. The hot dip galvanized layer is thick, the cost of electro-galvanized is low, and the surface is not very smooth.
2. Different working principles
The hot dip galvanized tube is to make the molten metal react with the iron matrix to produce an alloy layer, so that the matrix and the coating are combined. Hot-dip galvanizing is to pickle the steel pipe first. In order to remove the iron oxide on the surface of the steel pipe, after the pickling, it is cleaned in a tank with ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to In the hot dip plating tank.
The surface of galvanized steel pipe is welded steel pipe with hot dip galvanized or electro-galvanized layer. Galvanizing can increase the corrosion resistance of the steel pipe and prolong the service life. Galvanized pipe has a wide range of uses. In addition to line pipes for conveying water, gas, oil and other general low-pressure fluids, it is also used as oil well pipes and oil pipes in the petroleum industry, especially offshore oilfields, as well as oil heaters and condensation for chemical coking equipment such as coal-distilled wash oil exchangers, pipe piles for trestle bridges, and pipes for support frames in mine tunnels.
3. Different features
Hot dip galvanizing has the advantages of uniform coating, strong adhesion and long service life. Complicated physical and chemical reactions occur between the steel pipe matrix and the molten plating solution to form a corrosion-resistant zinc-iron alloy layer with a compact structure. The alloy layer is integrated with the pure zinc layer and the steel pipe matrix. Therefore, its corrosion resistance is strong.
Hot dip galvanized tubes are widely used in construction, machinery, coal mines, chemicals, electric power, railway vehicles, automobile industry, highways, bridges, containers, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery and other manufacturing industries.