1.How should rust prevention and vapor phase protective coatings be packaged?
Standard practice: Tightly wrap the inner, outer, and end faces of the steel coil with special rust-preventive paper or neutral paper.
Advanced solution: For high-value cold-rolled coils requiring long-term sea transport or storage in high-humidity environments, vapor phase corrosion inhibitor (VCI) paper should be used. It continuously releases rust-preventive agents, adsorbing onto the metal surface to form a protective layer, providing rust prevention even in areas where the paper does not adhere completely.
2.How should auxiliary protection and buffer layers be packaged?
Wrapping: The inner and outer circumferences of the steel coil are sealed with inner and outer circumferential wrapping plates (usually corrugated cardboard or plastic sheets) to form a smooth, enclosed surface.
Corner Protectors: Paper or plastic corner protectors must be installed along the inner and outer edges of the steel coil. In high-grade packaging, additional iron (steel) inner and outer corner protectors are added to withstand severe impacts during lifting and transportation, and to prevent the straps from damaging the internal paper.
3.How do physical seals and barrier layers provide protection?
Standard Practice: The entire steel coil (or a coil already wrapped with rust-proof paper) is fully sealed in a plastic sleeve (plastic film), with seams tightly sealed with tape.
Export/High Humidity Environment Solution:
Aluminum Foil Composite Film: Aluminum foil plastic composite film bags are used for fully sealed packaging. The aluminum foil layer provides excellent protection against water vapor and oxygen.
Built-in Desiccant: High-efficiency desiccants (such as silica gel or molecular sieves) are placed inside the sealed film in a specific ratio. Industry experience reference: For high-humidity sea transport, the desiccant dosage can reach 300g/m³ to absorb residual moisture inside the packaging, ensuring the relative humidity inside the packaging remains below 40% for an extended period.
Double Sealing: In some extreme environments, a double-sealing process using two barrier films (such as an inner VCI film + an outer aluminum foil film) is employed.
4.How to protect mechanical fasteners and marking layers?
Bundling: Use high-strength steel strapping (or plastic-coated steel strapping) for radial (around the circumference of the steel coil) and circumferential (through the core) binding, typically at least three times in each direction. Corner protectors should be placed at the binding points to prevent the steel strapping from damaging the packaging and the steel.
End Protection (Optional): For the highest grade packaging, iron (steel) round end protectors (end plates) are added to both ends of the steel coil, completely covering the end faces like caps, before the entire coil is tightly bound.
Labeling: Finally, affix a secure label indicating product information, specifications, batch number, and storage and transportation markings such as "Keep Dry" and "Here".
5.What are the differences in the cost of different packaging options?
Rust-preventive oil coating: Suitable for short-term, environmentally controlled transportation. However, degreasing and cleaning are required later, which may affect subsequent processing (such as welding).
VCI vapor phase corrosion inhibitor paper: Suitable for most cold-rolled coils. It offers excellent rust prevention and has a clean surface; it can be used directly after opening without cleaning.
Desiccant + aluminum foil seal: Suitable for high-value electrical steel, silicon steel, or products requiring long-term sea transport/storage. Provides ultimate moisture protection.