In the 1930s, the United States Steel Corporation developed Cor-Ten Steel that was primarily for use in railway coal wagons. The controlled corrosion that is a feature of the material was a welcome by-product of the need for a tough steel capable of withstanding the rigors of America’s garbage yards and collieries. Because of its inherent toughness, weathering steel (the generic name for Cor-Ten, along with weather-resisting steel) was and still is used extensively for ISO shipping containers. (RSCP)
When I read this introduction on one of my sources for my research project, it really intrigued me to think about how far Cor-Ten steel has come. That it was originally used as a structural rust-resistant element is interesting. All of the research I had found before this stated that Cor-Ten appeared in the 1960s. This source explained that at this time the civil engineering of this product occurred during this time which lead to its popularity in construction other than railway coal wagons. This engineered steel improved the resistance to corrosion (RSCP). Cor-Ten 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 smelted in blast furnaces is reduced in a converter. This also interests me because this could mean that the Iron Range in Minnesota heavily influences the construction of Cor-Ten steel.
This source stated that weathering steel has a combination of chromium, copper, silicon and phosphorus, the amounts depending on the exact attributes required. I wonder if that means the different levels have a direct effect on the weathering of the steel or maybe just affect the weight. I have read that weather-resistant steel works by controlling the rate at which oxygen in the atmosphere can react with the surface of the metal. Iron and steel both rust in the presence of air and water, which results in visual corrosion.
I am interested in investigating further when exactly Cor-Ten became a choice for siding. As it is heavily prominent in North America, does that have to do with the resources? Perhaps personal interest. The progress of Cor-Ten steel is my research topic and I would like to understand how steel works as a structural element as well as a aesthetically, if it works better in one way or the other, and if it is better suited for one environment vs another.