Corten steel

Corten steel (Cor-Ten - a combination of 'corrosion resistance' and 'tensile strength') is a brand name for weather-resistant or weathering steel. There is Corten steel A and B, with Corten steel A being more weather-resistant than Corten steel B. Specifically, material loss after ten years for Corten steel A is 30-75 μm and for Corten steel B 75-100 μm. For reference, the material loss for carbon steel (normal structural steel) after ten years is 150-200 μm.

Another difference is behavior at high temperatures. 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 425°C, and for carbon steel, it is 400°C. Due to these better heat-resistant properties, Corten steel is also used for outdoor stoves.

According to NEN-EN 10025-5, Corten steel A (type WP) almost corresponds to structural steel S355J0 and S355J2 (J0 means an impact strength of at least 27 J at 0°C, and J2 the same impact strength at -20°C), and Cor-Ten B (type W) with 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 artworks, flower boxes, and facade cladding but is sometimes also used in cranes and chimneys. The plates get their typical rust color only after a few months of exposure to the outdoors. However, products exist that accelerate this oxidation process. The best coloration occurs with a consistent mix of rain and dryness during the first months of exposure. One should keep in mind that rainwater running off the plates can cause rust-brown discoloration on surrounding materials.

Alinco stocks Corten steel A plates from 2 to 12 mm.