CORTEN steel is a kind of alloy steel, exposed to a few years after the outdoor surface can form a relatively dense layer of rust, and thus do not need to paint protection. Weather corrosion steel Corrosion resistance (tensile) and tensile strength (tensile strength) abbreviation for the trade name of the COR-TEN most known, so the British often "Corten Steel" on behalf of weathering steel.The main steel grade is CORTEN A and CORTEN B.