1. Pre-Treatment Process

During the pre-treatment stage, residual rolling oils, surface contaminants, and impurities on cold-rolled steel sheets are thoroughly removed. The sheets are passed through an alkaline cleaning solution under an electrically charged condition, generating an electrochemical reaction that ensures a clean and highly active surface for subsequent coating processes.

2. Annealing

The annealing process modifies and enhances the mechanical properties of pre-treated steel sheets through controlled recrystallization. This process improves material strength, ductility, and formability, providing the optimal metallurgical structure required for high-quality galvanized steel production.

3. Hot-Dip Galvanizing

After annealing, steel sheets pass through a molten zinc bath where a uniform zinc coating is applied to the surface. The coating thickness and weight are precisely controlled by removing excess zinc with a high-pressure air knife before solidification, ensuring consistent coating performance and excellent corrosion resistance.

4. Galvannealing

Following hot-dip galvanizing, the coated steel sheet undergoes a controlled reheating process to promote the diffusion of zinc atoms into the iron substrate. This forms a zinc-iron (Zn-Fe) alloy coating with enhanced weldability, paintability, and corrosion resistance, making it particularly suitable for demanding applications such as automotive manufacturing.

5. Skin Pass Mill (SPM) & Chemical Treatment

To achieve superior flatness, surface quality, and an attractive finish, galvanized steel sheets undergo skin pass rolling. A chrome-free chemical treatment is then applied to the surface to prevent white rust formation on activated zinc coatings while further improving corrosion resistance and long-term durability.

6. Inspection & Coiling

After surface treatment, galvanized steel sheets undergo comprehensive quality inspection to ensure compliance with strict requirements for surface appearance, coating uniformity, mechanical properties, and dimensional accuracy. Qualified products are then carefully coiled and prepared for shipment to customers.