Description

COR-TEN is the acronym for CORrosion resistance and TENsile strength, developed by U.S. Steel in the 1930s. It has been used in architecture since the 1960s.

01Patina chemistry

The composition includes additions of copper (0.25–0.55%), chromium (0.45–0.65%), nickel and phosphorus compared with ordinary carbon steel. These alloying elements accelerate the formation of the protective oxide layer within the first 18–36 months of atmospheric exposure.

Unlike conventional corrosion, the oxide formed by Corten is compact, adherent and self-healing: in the event of mechanical damage, it regenerates under alternating cycles of wetting and drying.

02Installation and construction detailing

During the first months of exposure, Corten produces surface run-off that can stain underlying porous surfaces (concrete, light-coloured stone, renders). The technical detailing must provide drip edges, spacers and protection of adjacent surfaces.

Fixings must be made of AISI 316 stainless steel to avoid galvanic coupling. Welding requires specific electrodes compatible with the alloy composition.

Technical identity

Standards

European and international references applicable.

EN 10025-5ASTM A588ISO 14025EN 15804EN 1090

Physical properties

Elastic modulus210 GPa
Thermal expansion12x10⁻⁶/°C
Thermal conductivity47 W/mK
Electrical resistivity0.16 ohm*mm2/m

Usage environment

Temperate climates with wet-dry cycles. Not suitable for direct marine environments or areas with permanent water stagnation.

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