Export Packing for Steel: Anti-Corrosion, Crating and Loading a Container That Arrives Clean

Steel can survive a six-week sea voyage in perfect condition or arrive as a rusty, dented mess, and the difference is almost entirely the packing. A consignment of galvanized gratings once reached a customer in Lagos with white rust blooming across the surface. The galvanizing was fine. The problem was that the bundles had been packed tight while still damp, sealed in plastic that trapped condensation, and left to sweat inside a steel container crossing the equator. The metal was never the issue. The packing was. Container sweat, salt and rough handling are the three things every export packing plan has to beat.

Why steel arrives damaged, and it is rarely the steel

Three things attack a steel shipment at sea. The first is condensation, the container sweat that forms when warm humid air trapped in the box meets a cold steel wall at night and rains back down onto the cargo, which is exactly what blooms into white rust on fresh galvanizing. The second is salt, in the sea air and spray, which settles on the surface and drives corrosion wherever moisture follows. The third is mechanical, the shoving and dropping of handling and the shifting of a badly secured load in a rolling ship. A packing plan has to answer all three, not just wrap the goods and hope for calm weather.

Beating corrosion inside the box

• Pack dry. Never seal damp steel in plastic. Let galvanized and bright surfaces dry fully before wrapping, because trapped moisture is what turns into white rust.
• Use VCI, not cling film. Volatile corrosion inhibitor paper or film releases a protective vapour and lets the surface breathe, far better than plastic that seals water against the steel.
• Add desiccant and let it breathe. Desiccant bags inside crates and desiccant poles in the container soak up the moisture that causes sweat; many loads travel better vented than sealed.
• Oil or grease machined and bright surfaces. A rust-preventive film on unplated steel, threads and machined faces carries them through the voyage.
• Protect edges and faces. Edge guards and interleaving stop the chafe that breaks coatings and starts rust at the damage.

Crate, bundle or load loose

How you contain the goods depends on what they are and how they will be handled. Long items like cable tray, ladder sections and gratings are usually steel-strapped into bundles on timber runners, so a forklift or sling can lift them without bending them, with the strapping cushioned so it does not cut into the coating. Fragile or high-value fabrications go into timber crates or cases. Heavy loose items get skids and bracing. The aim every time is a unit that can be lifted, stacked and lashed without anyone handling the bare steel, because every extra touch is another chance to dent a corner or scrape a coating.

The wood rule that holds shipments at the border

Any solid wood packing, the pallets, crates, runners and dunnage, has to meet ISPM-15, the international rule on wood packaging, which means it is heat-treated or fumigated and stamped with the IPPC mark. This is not optional and it is not a formality. Customs in the importing country will hold, and sometimes destroy or re-export at your cost, a shipment whose wood is not ISPM-15 compliant and stamped. Use treated, stamped timber, keep the treatment record with the documents, and if you want to avoid the question entirely, use plywood or engineered board, which is exempt. We use only ISPM-15 stamped timber and note it on the packing list.

Loading the container so it arrives as it left

A well-packed load can still arrive damaged if the container is loaded badly. Spread the weight evenly across the floor and stay within the container payload and the road axle limits at both ends, because an overloaded or unbalanced box is a problem long before and after the sea leg. Block and brace the cargo so it cannot shift when the ship rolls, filling the gaps with dunnage, airbags or lashing. Keep heavy items low and never stack point loads on lighter goods. Line the floor where sweat may drip. And photograph the loaded container before the doors close, because that photograph settles most damage claims.

The steel almost never fails the voyage. The packing does. Pack it dry, beat the sweat with VCI and desiccant, stamp the wood to ISPM-15, and photograph the load before the doors shut.