Hot-dip galvanized steel pipe: hot-dip galvanized steel pipe is first steel fabricated parts for pickling, in order to remove the iron oxide on the surface of the steel fabricated parts, after pickling, through the ammonium chloride or zinc chloride aqueous solution or ammonium chloride and zinc chloride mixed aqueous solution tanks for cleaning, and then sent to the hot-dip plating tank.
Cold galvanizing is also called electro-galvanizing: it is the use of electrolytic equipment will be fittings after degreasing, pickling into the composition of zinc salts in the solution, and connected to the electrolytic equipment of the negative electrode, in the fittings on the opposite side of the placement of the zinc plate, connected to the electrolytic equipment in the positive electrode connected to the power supply, the use of electric current from the positive electrode to the negative electrode of the direction of the movement of the fittings will deposit a layer of zinc, cold plating of the fittings is first processed and then zinc-plated.
The main differences between the two are as follows
1.There is a big difference in the mode of operation
The zinc used in hot-dip galvanizing is obtained at a temperature of 450 ℃ to 480 ℃; and cold galvanized steel pipe in the zinc, is obtained at room temperature through the electroplating process.
2.There is a big difference in the thickness of the galvanized layer
Hot-dip galvanized steel pipe zinc layer itself is relatively thick, there are more than 10um thickness, cold galvanized steel pipe zinc layer is very thin, as long as the thickness of 3-5um
3.Different surface smoothness
Cold galvanized steel pipe surface is not smooth, but compared to hot-dip galvanized smoothness is better. Hot-dip galvanized although the surface is bright, but rough, there will be zinc flowers appear. Although the surface of cold galvanized smooth, but there will be gray, stained performance, good processing performance, corrosion resistance is insufficient.
4.Price difference
Manufacturers in order to ensure quality, hot-dip galvanized steel pipe in general will not use electro-galvanized this galvanizing method; and those small-scale enterprises with relatively obsolete equipment, most of them will use electro-galvanized this way, and thus the price of cold galvanized steel pipe is lower than hot-dip galvanized steel pipe.
5.Galvanized surface is not the same
Hot-dip galvanized steel pipe is the steel pipe is fully galvanized, while cold galvanized steel pipe is galvanized only one side of the steel pipe.
6.Significant difference in adhesion
Cold galvanized steel pipe adhesion than hot-dip galvanized steel pipe adhesion is poor, because the cold galvanized steel pipe steel pipe matrix and the zinc layer is independent of each other, the zinc layer is very thin, and is still simply attached to the surface of the steel pipe matrix, and it is very easy to fall off.
Application difference:
Hot-dip galvanized pipe is widely used in construction, machinery, coal mining, chemical industry, electric power, railway vehicles, automobile industry, highway, bridge, container, sports facilities, agricultural machinery, petroleum machinery, prospecting machinery and other manufacturing industries.
Cold galvanized pipe in the past is often used, gas and water supply system, while there are other aspects of fluid transportation and heating supply. Now cold galvanized pipe has basically withdrawn from the field of fluid transportation, but in some fire water and ordinary frame structure will still use cold galvanized pipe, because the welding performance of this pipe is still very good.
Post time: Jan-08-2024
