1.What are the advantages of choosing VCI vapor phase corrosion inhibitor + polyethylene?
Cold-rolled coils have no surface coating. In rainy weather or high-humidity environments like sea transport, ordinary gaskets will absorb water and, when applied to the coil edges, will seep out yellow rust within 24 hours.
Correct Selection: VCI anti-rust composite gaskets must be selected. Its bottom layer is physical shock absorption (foamed PE), and the top layer contains vapor-phase rust inhibitors that continuously release rust-preventing gases, completely covering the edges of the steel coil.
Avoidance: Do not use recycled material gaskets (dark gray, poor elasticity), as the acidic substances in recycled materials will corrode the steel plate; do not use pure paper gaskets, as they will collapse upon exposure to moisture.
2.In what ways are three-sided corner protectors superior to flat pads?
C-shaped/U-shaped corner protectors (recommended): These not only cushion the base but also enclose the outer and inner rings of the steel coil. During sudden braking, the coil lurches forward, and the vertical side wings provide protection, significantly increasing friction.
Size matching: The shim width must be greater than the steel coil width. For example, if the steel coil is 1200mm wide, the shim should be at least 1400mm wide, with the excess portion curving upwards to prevent the coil edges from biting into the truck bed floor.
3.How about hardness and thickness?
Single-layer transport (bare coil directly placed on the pallet): Use medium-density or high-density foamed PE. Softer materials (such as EPE pearl cotton) will be instantly flattened to paper-thin by a 20-ton steel coil, completely losing their cushioning effect.
Multi-layer stacking (top over bottom): The lower layer of padding must withstand the entire weight of the upper steel coil plus impacts. In this case, ultra-high-density polyethylene (UHDPE) is required, with a recommended thickness of 20mm or more. If the padding is compressed to less than 1/3 of its original thickness, it indicates insufficient hardness, and the specification must be changed.
Special treatment for thin materials: For extremely thin cold-rolled coils (less than 0.3mm thick), the edges are prone to wrinkling. It is recommended to attach a layer of felt to the contact surface between the padding and the steel coil to increase flexibility.
4.What solutions are available for special scenarios?
Scenario A: Export by Sea (40-60 days)
PE gaskets alone are insufficient. VCI rust-proof gaskets with heat-shrink film wrapped around the outside are required.
Sea freight involves heavy salt spray. If the gasket absorbs water and doesn't evaporate, black edges (slight oxidation) will form on the steel coil. Although the thickness remains the same, customers will refuse delivery. The gasket width should be 100-200mm wider than for land transport to minimize rainwater penetration.
Scenario B: Extreme Low Temperatures (Northern Winters)
Ordinary PE gaskets become hard and brittle below -20℃, cracking easily upon impact.
Low-temperature resistant modified PE or polyurethane (PU) gaskets must be used, maintaining elasticity even at low temperatures.
5.What are the simplified acceptance standards?
Fingernail Test: Squeeze the gasket firmly. If it's completely impossible to squeeze (like hard plastic), it's too hard; if you can easily squeeze it to the bottom, it's too soft. A fingernail should be able to penetrate 1-2mm and have a springy feel, indicating moderate density.
Tear Test: High-quality gaskets are difficult to tear by hand, and the resulting tear has a dense honeycomb pattern. Recycled materials tear easily, with a smooth tear.
Rust Resistance Verification: Genuine VCI gaskets have a faint odor (rust inhibitor evaporation) upon opening the packaging. When a drop of water is placed on the gasket, the water droplet will not immediately penetrate and spread.