Galvanized steel pipes are welded steel pipes with hot-dip galvanized or electro-galvanized layers on the surface. Seamless galvanized pipe is one of them. Galvanizing can increase the corrosion resistance of the steel pipe and prolong its service life. Galvanized pipes have a wide range of uses. In addition to line pipes for conveying water, gas, oil and other general low-pressure fluids, they are also used as oil well pipes and oil pipes in the petroleum industry, especially offshore oilfields, as well as oil heaters and condensate for chemical coking equipment. Pipes for coolers, coal-distilled wash oil exchangers, pipe piles for trestle bridges, and pipes for support frames in mine tunnels, etc.
The characteristics of galvanized steel pipe are as follows:
1. The zinc coating is thick, with detailed, uniform and non-porous crystals, and excellent corrosion resistance;
2. The zinc layer obtained by electroplating is relatively pure, and it corrodes slowly in the mist of acid, alkali, etc., and can effectively maintain the steel substrate;
3. Because the zinc coating has excellent ductility, it can be formed by cold punching, rolling, bending, etc. without damaging the coating.
4. The zinc coating is passivated by chromic acid to form white, colorful, military green, etc., beautiful and generous, with certain decorative properties;
5. A thick and dense pure zinc layer covers the surface of the steel, which can prevent the steel substrate from touching any corrosive solution and protect the steel substrate from corrosion. In the general atmosphere, the surface of the zinc layer constitutes a very thin and dense zinc oxide layer surface, which is difficult to dissolve in water, so it has a certain maintenance effect on the steel substrate. If zinc oxide and other components in the atmosphere form insoluble zinc salts, the anti-corrosion effect is more promising.
6. With iron-zinc alloy layer, combined with compactness, it exhibits unique corrosion resistance in marine salt spray atmosphere and industrial atmosphere;
7. Because of the strong combination, zinc and iron are mutually soluble and have strong wear resistance;
8. After the steel structural parts are hot-dip galvanized, it is equivalent to one annealing treatment, which can effectively improve the mechanical function of the steel matrix, eliminate the stress during the forming and welding of the steel parts, and is beneficial to the turning of the steel structural parts.
9. Because zinc has excellent ductility and its alloy layer is firmly attached to the steel base, hot-dipped parts can be formed by cold punching, rolling, wire drawing, and bending without damaging the coating;
10. The surface of the parts after hot-dip galvanizing is bright and beautiful.
11. The pure zinc layer is a layer of galvanized layer endowed with plasticity in hot-dip galvanizing. Its properties are basically close to pure zinc and have ductility, so it is rich in flexibility.