1.What are the characteristics of hot-dip galvanizing process?
The coating is thick (typically 50-200g/m², double-sided) and offers excellent corrosion resistance, making it suitable for outdoor applications and heavy industry, where corrosion protection is critical.
Production process: Degreasing the steel strip → Pickling and rust removal → Cleaning → Annealing (reducing the steel strip surface) → Immersing in zinc bath (440-460°C) → Cooling → Post-treatment (such as passivation and oiling).
2.What are the characteristics of electrogalvanizing process?
Process Features:
The coating is uniform and has a controllable thickness (typically 5-30g/m²). The surface finish is highly polished, making it suitable for subsequent fine processing such as painting and stamping.
Production Process: Degreasing the steel strip → Pickling → Electroplating (in a zinc ion solution, with the steel strip acting as the cathode) → Cleaning → Passivation (to improve corrosion resistance).
Advantages: The coating thickness can be precisely controlled, making it suitable for applications requiring high surface quality (such as automotive panels and appliance housings).
3.What are the characteristics of alloy hot-dip galvanizing process?
After hot-dip galvanizing, an additional heat treatment allows the zinc layer to diffuse into the iron atoms on the steel strip surface, forming a zinc-iron alloy coating (primarily composed of an Fe-Zn alloy, such as Γ and δ phases).
Process Features:
The coating provides strong adhesion to the substrate, excellent weldability (no porosity caused by zinc evaporation), and good paint adhesion.
The product, called "Galvanized Iron Alloy Coil (GA)," is primarily used for automotive body panels (parts requiring welding and painting).
4.What are the characteristics of zinc-nickel alloy electroplating process?
During the electroplating process, zinc and nickel are co-deposited to form an alloy coating (typically with a nickel content of 8-15%) by adjusting the electrolyte composition.
Process Features:
Corrosion resistance far exceeds that of pure zinc coating (salt spray testing can last over 1,000 hours), and it also offers excellent heat and wear resistance.
It is primarily used in high-end corrosion protection applications such as automotive parts, marine engineering, and petrochemical equipment.
5.What are the characteristics of mechanical galvanizing process?
Process Characteristics:
Suitable for small, complex-shaped workpieces, it provides uniform coatings without the risk of hydrogen embrittlement (suitable for high-strength steel). However, it is not commonly used for coil production due to its low efficiency.