Corten steel (brand name; standard designation “weathering structural steel”, e.g. S355J2W) is the wall material of almost all shipping containers. Alloying elements such as copper, chromium and nickel cause a dense, firmly adhering protective rust layer (patina) to form when the steel is exposed to the weather; this layer protects the steel beneath – unlike the loose rust on ordinary structural steel.
In practice, this means that a superficial, even “rust tint” on a used container is usually harmless. The only critical issues are holes all the way through, flaking rust and weakened welds, especially on the underside and the cross members. If you want to paint the container, you must lightly sand the patina and apply a primer.
More on this: Painting containers.
Last updated: 8 September 2026 · Editor: Coin Container Team, Hamburg