Hot-dip galvanizing is a commonly used method of metal corrosion prevention, mainly applied to the surface treatment of iron and steel products.
Author: Anna
Hot-dip galvanizing is a commonly used method of metal corrosion prevention, mainly applied to the surface treatment of iron and steel products. The basic principle of hot-dip galvanizing is to melt zinc by high temperature, and then immerse the steel products in the zinc solution, so that iron and zinc at the interface of metallurgical reaction occurs, forming a layer of dense zinc-iron alloy layer and pure zinc layer, so as to achieve the purpose of preventing corrosion of steel.
The process of hot-dip galvanizing mainly includes the following steps:
Pre-treatment: The parts to be galvanized are acid-washed to remove surface impurities such as oxidized skin, rust and grease to ensure the bonding strength of the coating.
Zinc dipping: The pre-treated workpiece is put into the molten zinc liquid, the temperature of which is usually 440-460℃. At high temperature, iron reacts with zinc to form a zinc-iron alloy layer.
Cooling: After removing the workpiece from the zinc solution, it needs to be cooled quickly to prevent the zinc layer from becoming too thick or from crystallizing poorly.
Post-treatment: The cooled workpieces need to be passivated to form a dense oxide film to further improve corrosion resistance.
The advantages of hot-dip galvanizing are uniform coating, strong adhesion, good corrosion resistance, and relatively low cost, suitable for mass production.
However, hot-dip galvanizing also has certain limitations, for example, for workpieces with complex shapes and large sizes, the coating may not be uniform; in addition, the hot-dip galvanizing process generates a large amount of heat and fumes, which requires appropriate environmental protection measures.
Overall, hot-dip galvanizing is a very effective metal corrosion prevention technology, which is widely used in many fields such as construction, electricity, transportation and agriculture.