Decorative rusty steel

The decorative rusty steel, commonly called as corten steel in Spain and other parts of the world (in some parts it is also known as worn steel or patinable steel) it is a type of steel made with a chemical composition that causes its oxidation to have particular characteristics where the oxide itself protects the steel from corrosion. Atmospheric corrosion creating a superficial film of impermeable oxide that prevents the corrosion of the steel from continuing inside.

The high content of copper, chromium and nickel in corten steels makes them acquire a very particular orange color. This orange color varies in hue depending on the amount of oxidation in the steel (in aggressive environments the hue varies towards a dark brown).

Brief history of corten steel

Corten steel was developed by the American company United States Steel Corporation in 1933 and was originally designed to help build coal railway cars so that they would wear less. In the 1960s, the first building with this type of steel was built (the headquarters of the American company John Deere). In Spain, some of the buildings built with corten steel are: Caixa Forum Madrid Cultural Center, Barcelona Botanical Garden or the Euskalduna Palace in Bilbao.

Corten steel composition

The anticorrosive properties of corten steel are due to its chemical composition with a special alloy of copper, chromium, phosphorus and silicon, on the surface of the metal that generates what is known as patina, which is an oxide film of special composition and high density that internally protects the steel from corrosion.

Decorative oxidized steel basically consists of an alloy with a low carbon content (less than 0.25%) which, in addition to small amounts of copper (Cu), nickel (Ni) and chrome (Cr) and exposed to cycles of humidity and dryness, develops a homogeneous and highly adherent oxide layer on the surface of the steel exposed to weather conditions.

Corten steel in Europe is manufactured according to the EN 10025-5 standard and in the United States according to the ASTM A242 and ASTM A588 standards.

Advantages of weather resistant decorative rust steel:

• Durability: 4 to 8 times higher than common steel.
• Mechanized: hot and cold forming, gas cutting.
• Excellent weldability: any type of welding.
• Avoid anti-corrosion paint work or galvanic paint.
• Low maintenance cost.
• Greater resistance of the coating, better adherence to the base of the painted products.
• Attractive look for architecture.