Like a fine wine, weathering steel is enriched by air and enhanced with age. When exposed to the natural environment, this magical steel develops a beautiful patina which serves as protective armour and is the basis for the steel’s trademark purplish brown colouring. The marvellous paradox of weathering steels is that rust protects the steel from rust! Weathering steel is also known as corten steel. This comes from the original brand name COR-TEN© which was registered in 1933 by US Steel Corporation. ‘COR’ comes from CORrosion resistance, while ‘TEN’ comes from TENsile strength – two of the properties of weathering steels. Since its development, weathering steel has been used in almost every steel application. Bridges, railway cars, smokestacks, buildings, and works of art have all utilised weathering steels. The first major work in weathering steels was realised by Eero Saarinen who designed the John Deere World Headquarters in Moline (USA) in 1960. It was also used in the 1977 New River Gorge Bridge in West Virginia (USA).
Since the 1970s, the use of weathering steels has spread through Europe. Engineers appreciate its high yield strength and corrosion resistance. Weathering steels also reduce maintenance to nearly zero and
can lighten the weight of structures. These advantages make it a very economic material and led to the construction of thousands of bridges and viaducts around the world. Architects like the expressiveness of the material and its ability to fit into urban landscapes and natural environments.
Today, weathering steel is more fashionable than ever. It fits with modern ideas that architecture and infrastructure should blend in with the natural and built environment. Using our decades of experience with corrosion resistance mechanisms.