Weathering steel products are formulated from Atmospheric Corrosion Resistant Steel grades, which are alloys that rapidly oxidise after installation. The product reacts with elements in the air to form a thick, regenerating patina. While this characteristic is actively removed from other steel products by manipulating the alloying composition, weathering steels are alloyed specifically for this purpose. The patina acts as a naturally resistant coating that protects the internal structure of the steel from corrosion. It is a recursive reaction, meaning the layer will self-replicate if damaged by extraneous elemental factors such as wind or rain. In other words: weathering steel products protect themselves from atmospheric corrosion.
Structural steel products for outdoor applications often require expensive treatment methods to ensure that the metal will not corrode over time. Otherwise, the mechanical integrity of steel plates and beams can be rapidly reduced by uncontrolled oxidation, resulting in structural decay and likely collapse. Weathering steel products are an ingenious and cost-effective solution to this problem, with reduced installation considerations and maintenance costs. This twofold advantage is ideal from a budgeting perspective, but weathering steel is often applied as much for its aesthetic appeal as its cheapness.
The distinctive patina of weathering steel products has an undeniable charm that has been exploited by architectural designers across the world. Artistic sculptures and building facades have been designed using weathering steels, with vibrant orange detailing developing organically as the material gradually reacts with pollutants in the atmosphere.
The oxidation process of weathering steel products is actively catalysed by pollutive elements in air, suiting the material to urban environments more so than rural ones. However, noteworthy bridges and sculptures have been constructed of weathering steels in less densely populated areas. Just a few notable examples of aesthetic weathering steel projects include:
- The Angel of the North (UK);
- The Centre for Contemporary Art, Melbourne (Australia);
- Matsunoyama Natural Science Museum (Japan).
Weathering Steel Products and Services from Masteel
Masteel supplies several grades of weathering steel at a variety of plate dimensions and thicknesses, with a range of in-house cutting and profiling services to cater for bespoke steel product parameters. Our weathering steel grades includes:
- Corten A: a copper-chromium-nickel alloy with added phosphorous for increased aesthetic patina formation. Available in plate thicknesses of 6 – 12 mm, this weathering steel grade is ideally suited for aesthetic applications as opposed to structural or load-bearing applications;
- Corten B: a copper-chromium-nickel alloy with reduced phosphorous and a higher carbon content to improve the mechanical properties of the product. Also available in plate thicknesses of 6 – 12 mm, this weathering steel is more suitable for structural applications such as large sculptural projects;
- S355JOWP: an alternative to Corten A, this alloy is formulated from chromium nickel and copper with added phosphorous to expediate the weathering process of steel products. It is suitable for a broad range of applications, including steel bridges and stack gas structures;
- S355JOW Weathering Steel: an alternative to Corten B, this alloy is primarily suited for thinner material structures;
- S355J2W: an equivalent of Corten B, this alloy is fully recyclable and is suitable for numerous applications, including aesthetic and structural purposes.