Hot dip galvanizing and electro-galvanizing are two different processes for galvanized steel sheets.
Hot dip galvanized steel sheet is a thin steel sheet in which a thin steel sheet is immersed in a molten zinc tank to adhere a layer of zinc on the surface. At present, the continuous galvanizing process is mainly used for production, that is, the rolled steel sheet is continuously immersed in a galvanizing tank with the molten zinc to make a galvanized steel sheet.
When the surface-treated steel workpiece enters the Zn molten liquid (the high temperature is about 440℃ to melt the zinc ingot), the iron matrix reacts with the molten zinc, and the iron is dissolved to form a solid solution of Zn in α-Fe. Then interdiffusion to produce Fe-Zn alloy compounds. When the workpiece leaves the zinc melt, it brings out pure molten Zn to cover the alloy layer, forming a pure Zn layer.
The hot dip galvanized layer and the substrate have high bonding strength, can withstand greater friction and impact, and have better corrosion resistance.
Galvanized steel sheet is a composite material formed by steel and zinc.
Galvanized products combine the advantages of the two materials. Like the regular spangle galvanized steel has the strength and plasticity of steel, and has a corrosion-resistant coating. It has a wide range of applications in industrial fields such as construction, home appliances and automobiles.
In the atmosphere, the corrosion resistance of zinc is much stronger than that of steel. Under normal conditions, the corrosion resistance of zinc is 25 times that of steel.