1.What are the core advantages of galvanized coils as materials for express cabinets?
Excellent Corrosion Resistance - A Core Advantage
Challenges of Outdoor Environments: Express lockers are required to be placed outdoors year-round, subject to the erosion of sun, rain, snow, air humidity, and pollutants (such as salt, acids, and alkalis).
Galvanized Coating Protection: The zinc layer protects the steel base in two ways:
Barrier Protection: The dense zinc layer physically isolates the steel base from the corrosive environment.
Sacrificial Anodic Protection: Even if the zinc coating is scratched, exposing the steel, the zinc acts as a "sacrificial" corrosion before the iron, thus protecting the underlying steel base from rust. This ensures the longevity of the locker.
2.Why are galvanized coils ideal for express lockers?
Excellent Strength and Rigidity
Cold-rolled galvanized sheet metal has excellent mechanical properties, enabling the manufacture of sturdy cabinet structures that withstand the impact and compression of daily use and offer a certain degree of damage resistance (e.g., pry protection).
Excellent Processability
Galvanized coils (especially those that have been annealed) have excellent ductility and formability, making them ideal for sheet metal fabrication such as cutting, stamping, and bending. They can be used to create a variety of complex structural components, door panels, partitions, and more for express lockers.
A Perfect Base for Painting
Express lockers are often spray-painted in various colors (such as Fengchao's pink, China Post's yellow, and Cainiao's blue) and brand logos.
The clean and uniform surface of galvanized sheet metal provides an excellent base for subsequent powder coating. Excellent adhesion prevents the coating from flaking, ensuring a long-lasting, aesthetically pleasing appearance. The previously discussed "surface oil stain" issue is thoroughly addressed during regular production through a pre-treatment degreasing process to ensure coating quality.
3.What are the typical express cabinet materials and manufacturing processes?
Base material: Cold-rolled, low-carbon steel galvanized coil. Common zinc coating weights include Z60 (60g/m²) and Z80 (80g/m²), which can be selected based on the specific cabinet components and corrosion protection requirements.
Pretreatment: After flattening, shearing, stamping, and bending, the steel plate enters the pre-painting line, which includes the following:
Degreasing: Removal of all oils and contaminants, such as rolling oil and rust-proofing oil, discussed previously.
Conversion treatment (phosphating or passivation): Forming a conversion film on the metal surface, further enhancing corrosion resistance and paint adhesion.
Surface coating:
Powder coating: This is the most popular process. Powder coating is applied to the cabinet surface through electrostatic attraction and then cured at high temperature. The resulting powder coating is uniform in thickness, wear-resistant, and weather-resistant, and available in a variety of colors.
Assembly: The painted components are assembled with internal components such as locks, screens, and circuit boards.
4.How does galvanized coil perform compared to aluminum?
It has good corrosion resistance and is lightweight, but its cost is higher than that of galvanized steel sheets and its strength is relatively low, so it is rarely used in structural parts that require high strength.
5.How does galvanized coil compare to stainless steel?
It has excellent corrosion resistance, but the cost is very high. It is usually only used in some high-end customized cabinets or special parts with extreme corrosion protection requirements. Due to cost considerations, large-scale express cabinets rarely use it in the entire cabinet.