Shipping Container Materials: COR-TEN Steel

10.01.2022 - Posted by Ryan Herr Updated On 11.07.2022

One of the key differences between international shipping containers, especially those that travel on the sea, and domestic containers which travel primarily on highways and possibly train cars, is the material that their outer shell is constructed of Sea containers are constructed out of COR-TEN Steel, or "weathering steel", while domestic containers are normally constructed out of aluminium or steel.

First, let's take a closer look at what COR-TEN Steel is.COR-TEN steel has also been called Corten steel (without the hyphen), or weathering steel; and was trademarked by US Steel, a trademark currently owned by Arcelor-Mitaal. This type of steel is produced by using a special type of processing that alters the chemical composition and it gives the steel an extra protective later on the surface that is extremely resistant to the natural corrosion caused by weather.A unique feature of this type of steel is that the surface layer continually regenerates when subject to weather. Basically, allowing the steel to form a thin layer of surface rust causes a strong protective coating. The one danger of using COR-TEN steel is in the welding process. While the steel isn't rust proof, it's important to now allow water to gather and change the corrosion process. The key areas on a shipping container that can be impacted by this are the welded seams and corners. Combine COR-TEN steel with the special types of paints that are used for painting shipping containers and the final product is a very strong box.

Domestic and Sea containers are manufactured to roughly the same dimensions, but the materials that go into them tend to vary. The largest, most notable difference is the type of steel used in the shell. Domestic shipping containers can be made out of aluminium as they tend to take less abuse than sea containers, abuse through transfer/transportation and harsh weather conditions. Using aluminium as the shell saves approximately 700lbs on a 20' container and 1400lbs on a 40' container. This reduction in weight transfers into a significant fuel savings over the life of the aluminium shipping container.
If you're planning on purchasing a shipping container, it's best to have a strong understanding of what you're planning on doing with the container and how long you'll need it. Aluminium containers have a useful lifespan of 6 years, while a COR-TEN steel shipping container has a lifespan of 15 years.
Depending on the age of the container when you purchase it, and the length of your project, the cost saving associated with an aluminium container may be outweighed by the long term investment.

Weathered Shipping Container
COR-TEN Steel

COR-TEN steel is an important component that contributes to the life span, durability, and security of intermodal sea containers. Regardless of whether it's a 20' shipping container or 40' shipping container, the benefit of COR-TEN over aluminium for international, overseas shipping is apparent.