Weathering steel, best-known under the trademark COR-TEN steel and sometimes written without the hyphen as "Corten steel", is a group of
steel alloys which were developed to eliminate the need for painting, and form a stable rust-like appearance if exposed to the weather for several years.
The original COR-TEN received the standard designation A 242 ("COR-TEN A") from the ASTM International standards group. Newer ASTM grades are A 588 ("COR-TEN B") and A 606 for thin sheet. All alloys are in common production and
"Weathering" refers to the chemical composition of these steels, allowing them to exhibit increased resistance to atmospheric corrosion compared to other steels.
This is because the steel forms a protective layer on its surface under the influence of the weather.The corrosion-retarding effect of the protective layer is produced by the particular
distribution and concentration of alloying elements in it. The layer protecting the surface develops and regenerates continuously when subjected to the influence of the weather. In other words,
the steel is allowed to rust in order to form the 'protective' coating.
These are the mechanical properties.
Regarding our sector, the COR-TEN Steel covers with a uniform coated its surface.
This kind of film is composed by oxide and other elements wich allows to extend the corrosion.
This kind of covering (generellay brown) looks like a valid barrier the corrosion extension.
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