In the 1930s, the United States Steel Corporation developed Corten, primarily for use in railway coal wagons. The controlled corrosion that is a feature of the material was a welcome by-product of the tough steel which can withstand the rigours of America's marshalling yards and collieries. Because of its inherent toughness, weathering steel (the generic name for Corten, along with weather-resisting steel) is still used extensively for containers.
The civil engineering applications that appeared in the early 1960s made direct use of Corten’s improved resistance to corrosion, and it would not be long before applications in architecture would become apparent.
Corten gets its properties from a careful manipulation of the alloying elements added to steels during the production process. All steel produced by the primary route (in other words, from iron ore as opposed to scrap) comes into being when the iron is smelted in blast furnaces and is reduced in a converter. The carbon content is lowered and the resulting iron, now steel, is less brittle and has a higher capacity for loading than before.