Most shipping containers are made of metal. But not just any metal. Most use Corten steel — weathering steel — for walls, doors, and other vital structures. It’s designed to react with the elements, forming a protective layer when rust is included. It makes it durable enough to handle repeated trips across the ocean.
Cross Members
Most components in a shipping container, including the corrugated walls, frame, and cargo doors, are made from corten steel. Sometimes referred to as weathering steel, this unique variety of metal has been developed by container companies to have increased resistance against atmospheric corrosion, meaning that it naturally forms a protective layer against the elements. Shipping containers spend years traversing the oceans and are consistently exposed to pounding winds, rain, sunshine, and seawater. That’s why they’re so tough and durable – designed to protect their precious cargo!
A shipping container’s floor frame has cross members, also known as joists. The joists create a space between the floor and the ground, which prevents moisture from seeping into the container flooring and potentially damaging the contents. The cross members are also one of the reasons why shipping containers don’t require a foundation, as they lift the entire floor frame away from the ground, minimizing damage from natural elements.
Corten Steel
Shipping containers have revolutionized how companies move cargo worldwide – whether patio furniture from Thailand bound for a Milan retailer or avocados headed for a grocery store in Berlin. They are incredibly durable structures and built to withstand the elements – including extreme temperatures at sea. Corten steel—also called weathering steel—is used to make the majority of shipping containers. It is a compound developed to give steel extra protection against atmospheric corrosion. Essentially, the steel self-heals by forming a protective layer of rust. Other significant components of shipping containers, such as corner castings, frames, and doors, will also be constructed from Corten steel. However, aftermarket accessories like vents and door handles can be manufactured from other materials. The doors are usually fitted with waist-high locking bars that overlap a staple welded to the left-hand door and a lock box on the right-hand side, shrouding a padlock, hindering attempts at forced entry.
Vents
Shipping containers have small vents built into the side that help circulate air at sea. These vents can be sufficient for some uses of the container, such as storing lawn equipment or other items that are not sensitive to temperature changes. However, a sound ventilation system is essential for different services like office buildings, greenhouses, and homes. Without proper ventilation, moisture will build up inside the container and cause items to rot or mildew. It is valid for items stored for extended periods or in high-heat environments.
Various ventilation modifications are available for shipping containers, including louvers and turbine vents. Louvers are small holes on the sides of the shipping container that allow for passive ventilation, while turbine vents are a fan-like ventilation option that spins and sucks the air through to create circulation. These and other ventilation options are popular amongst people who turn shipping containers into apartments, offices, and greenhouses.
Corner Castings
Corner castings are the steel corners of an ISO shipping container that allow it to be connected to other containers horizontally and vertically and connect to transport modes such as ship, rail, and road. They also allow a shipping container to be lifted by cranes. A mold forms a solid metal material into a specific shape for each of the four corner castings in a container. The most common type of metal used is steel, as it has the tensile strength and corrosion resistance needed for an aqueous environment such as a shipping container traveling by sea. Once the corners are made, the doors are installed onto their frames and welded. Then, the wall panels and roof panels are welded in place to finish off the container. The final product is then tested by being thrown at an ocean wave to see how much it will resist damage from the elements.
