The basic property of the weathering
steel is its ability to create a protective layer on its surface in favorable environments. This protective layer called patina covers the surface of the whole structure, protects against external climatic influences and the construction resists completely without an anticorrosion coating,
evaluates the different development on typical surfaces affected by leaking water and explains the high degree of correlation dependence between measured corrosion loss and average thickness of corrosion products.
The development of weathering steels is described historically in detail in . Corrosion properties of steels containing larger amounts of copper were observed already in year 1910 . First weathering steel was patented in the United States in 1933. Steel with trademark USS Cor-Ten was mainly used for the production of rail vehicles. Steel has found application primarily for vehicles subjected to increased abrasion, most frequently for manufacturing of wagons transporting coal . First weathering steel bridges were built in 1964 in Michigan and New Jersey. Since 1968 weathering steel is used under the name “Atmofix” in the Czech Republic and can be used as a standard structural material without any corrosion protection. The weathering steel Atmofix is mostly used for bridge structures and lattice transmission towers. Currently, weathering steels are used mainly in bridge constructions. The use of weathering steel is in many cases economically advantageous. The fabrication and assembly costs of weathering steel structures are typically 2-10 % lower when compared with the structures protected with traditional corrosion protection systems. The economic advantage of using weathering steels is the elimination of costs connected with repairs or restoration without corrosion protection systems. The basic specific property of weathering steels is their improved corrosion resistance in atmospheric conditions. Scope of the papers published on the corrosion behavior of weathering steels in various atmospheric conditions is extensive and includes various characteristics of corrosion layers.