Corten steel (COR-TEN - a contraction of ‘corrosion resistance’ and ‘tensile strength’) is a brand name for weathering or weather-resistant steel. It comes in two alloys, Corten steel A and B, with Corten steel A being more weather resistant than Corten steel B. More specifically, the material loss after ten years for Corten steel A is 30-75 μm and for Corten steel B 75-100 μm. For the sake of comparison, in the case of carbon steel (normal structural steel), the material removal due to corrosion after 10 years is 150-200 μm.

Behaviour at high temperatures is another difference between A and B. Corten steel A retains its full strength and stiffness (yield strength, modulus of elasticity) up to 540°C. For Corten steel B this limit is at 425°C and for carbon steel at 400°C. As a result of these higher heat-resistant properties, Corten steel is also used for outdoor stoves.

According to NEN-EN 10025-5, Corten steel A (type WP) is substantially comparable to structural steels S355J0 and S355J2 (J0 means a notched impact value of at least 27 J at 0°C and J2 has the same notched impact value at -20°C) and Corten B ( type W) is comparable to S355J2 and S355K2. The mechanical properties of Corten steel A and B are almost the same.

Corten steel is mainly used for aesthetic applications such as art pieces, flower boxes and façade cladding, but is sometimes also used in cranes and chimneys. The sheets acquire their typical rusty colour after only a few months of exposure to the outside air. However, there are products that accelerate this oxidation process. The most beautiful discoloration occurs as a result of a balanced mix of rain and drought during the first months of exposure. It is worth keeping in mind that the rainwater running off the steel sheeting can lead to a rusty brown discoloration of the surrounding materials as well.

Alinco keeps standard 2 to 12 mm Corten steel sheets in stock.