Electro-galvanized Coil

Electro-galvanized Coil refers to a metal material that is treated on the surface of the steel coil by electroplating. It improves the corrosion resistance and oxidation resistance of steel by depositing a layer of zinc on the surface of the steel coil, and is widely used in construction, automobiles, home appliances and other fields.

When producing electro-galvanized coils, the steel coils are first cleaned, degreased and rusted to ensure a clean surface. The steel plates are then pickled and phosphated to form a phosphate layer to improve the adhesion of the zinc layer. The steel coils are then immersed in an electrolyte containing zinc ions. Through the action of current, the zinc ions are deposited on the surface of the steel coils to form a zinc layer. Finally, the galvanized steel coils are cold rolled and finished and cut into the required size, and packaged for easy transportation and use.

Common grades of electro-galvanized steel include DX51D, DX52D, DX53D, DX54D, SGCC, SECC, SECD, SECE. The grades can be used to indicate the plasticity, weldability, strength, toughness, stamping, corrosion resistance, and paintability of steel.

Differences between hot-dip galvanizing and electro-galvanizing:

Hot-dip galvanizing is to immerse the steel in molten zinc liquid, while electrogalvanizing is to deposit a zinc layer on the surface of the steel by electrolysis. The zinc layer of hot-dip galvanizing is thicker and more corrosion-resistant, but the surface of the zinc layer is not as smooth as that of electrogalvanizing; the zinc layer of electrogalvanizing is thinner and the surface is smoother, but the corrosion resistance is relatively weak.

Construction field: used for roofs, wall panels, fences, steel structures, etc.
Automotive industry: used for automobile bodies, chassis, parts, etc.
Home appliance manufacturing: used for the outer shells and internal parts of home appliances such as refrigerators, washing machines, and air conditioners.
Other fields: such as furniture manufacturing, electronic products, transportation facilities, etc.
 

1. Surface Protection and Moisture-Proofing

During transportation and storage, avoid direct contact with rainwater. It is recommended to completely cover the coils with a waterproof tarp and secure the edges to prevent moisture and oxidation of the zinc coating. If the surface becomes wet, wipe or air dry it immediately and store it in a ventilated, dry environment.

Inspect the integrity of the packaging. Use tape or plastic bags to reinforce damaged areas to reduce the risk of scratches during handling.

2. Loading and Transportation Environment

Select a loading and unloading site on elevated ground with good drainage to avoid stagnant water. Ensure the transport vehicle is airtight and regularly inspect for cracks and rust to prevent rainwater infiltration.

Zinc coils must be stacked steadily to avoid collisions that could cause the coating to dislodge.

3. Processing and Welding Requirements

Electro-galvanized coils have excellent weldability, but attention should be paid to the quality of the substrate annealing to prevent surface oxide films from affecting the coating's adhesion. A pickling treatment is recommended before welding to improve adhesion. Control the force during stamping to prevent the zinc layer from peeling due to its physical bonding properties (adhesion strength 30-50 N/cm).

4. Environmental Adaptability

The electroplated zinc layer is relatively thin (typically 5-50 g/m²) and is suitable for low-corrosion environments. If used in high-humidity or coastal areas, additional coating or passivation treatment is recommended for enhanced protection.

Avoid prolonged contact with acidic or alkaline substances to prevent chemical corrosion of the coating.

5. Regular Maintenance and Inspection

Regularly remove zinc slag during use to prevent accumulation exceeding 150 mm, which will affect heating efficiency. The zinc bath temperature must be controlled below 450°C and equipped with a real-time monitoring system.

During extended periods of non-use, the zinc should be drained or the pot should be kept warm to prevent deformation.

6. Special Process Precautions

If aluminum (content ≤ 0.02%) or lead is added, this should be done after the zinc-iron alloy layer is formed to minimize the impact on coating performance. Single-sided electrogalvanized coils are suitable for special welding requirements, such as those for automotive interior panels. During installation, the front and back sides must be distinguished.

These measures can effectively extend the service life of electrogalvanized coils and maintain their corrosion resistance.