How does the rusting process of corten steel work?


21 Oct. 2022





Corten steel has been a popular material in the garden for several years now. Many appreciate the material for the appearance it gives. Because of its warm color it gives peace, but in certain settings it is very playful and striking. Corten steel can be recognized by its orange-brown color. This is the “end result,” so one thing and another happens before it is fully rusted.

Wondering how the process works? Below I explain how corten steel gets its vibrant color.

First things first

What is corten steel made of? Corten steel is a metal alloy composed of iron, copper, phosphorus, silicon, nickel and chromium. Due to the dense layer of sulfates and phosphates, the steel protects against corrosion.

Rust process

Because Corten steel is bare steel at first, it looks far from the end result. This can take some getting used to at first. When Corten steel comes in contact with wet and dry weather conditions, it begins to rust. You can see that the gray metallic color is changing little by little. The colors change daily, creating a very beautiful dance of colors. The total rusting process takes a year to a year and a half.

Faster rusting

Are you someone who doesn’t want to wait long for the end result? No problem! You can also let corten steel rust faster. By using a rust accelerator, or oxidizer, you speed up the process of rusting. At Geroba, we offer our Oxidizer by 0.5L.

Another option to treat your corten steel is to varnish it. Varnish is an agent that looks like oil. It causes the rusting process to stop. You can varnish corten if you wish to place the item indoors. Varnish also gives corten steel a dark color, so if you like a strong and powerful color, this is a great option.

And now, enjoy it

The advantage to corten steel is that you don’t have to look after it. You put it in your garden, let nature do its work, and you enjoy it for years. Because corten steel is environmentally friendly and durable, you can integrate it into your garden with confidence.