COR-TEN® weathering steel

COR-TEN® is a registered trademark of United States Steel Corporation and may only be used for products produced by United States Steel Corporation or her licensees.

The original COR-TEN® A

equally complies to S355J0WP according to EN 10025-5 with CE mark

What is weathering steel?

When a structural steel is alloyed with copper (Cu), chromium (Ni), nickel (Ni) and phosphorus (P), the surface will oxidize in a special way as soon as it comes into contact with oxygen. This oxide layer is called patina and forms under the influence of varying (dry and wet) atmospheric conditions. The patina completely seals the steel off from the atmosphere and thus forms a corrosion-resistant coating. Depending on location and local conditions, it can take 2 to 6 years for the patina to fully form. During this period, the steel also changes color, from light brown, to orange-brown to dark brown.

COR-TEN® was introduced in 1933 by United States Steel Corporation as “CORrosion resistant high TENsile steel”. The product development was aiming for improved atmospheric corrosion resistance, but the final chemical composition also resulted in a - for that time - truly “high strength steel”, with a yield strength of min. 345 Mpa and a tensile strength of min. 485 Mpa. In addition to a longer lifespan due to the improved corrosion resistance, it was now also possible to design thinner (lighter) structures.

One of the very first applications of COR-TEN weathering steel was found in the construction of railway freight wagons. Many other applications, both industrial and architectural, would follow.

COR-TEN® is still, or perhaps more than ever, popular amongst architects because of its natural appearance, which can be combined well with modern construction materials, such as wood, concrete, glass, stainless steel, etc.

Various industries are also making undiminished use of COR-TEN® because of its longer lifespan and lower maintenance costs compared to non-weather-resistant steel and the price compared to stainless steel.

Today, COR-TEN® weathering steel is increasingly used in combination with paint coating systems. The adhesion between the steel surface and the primer is undoubtedly good. In case of damage to the final coating, exposing the steel surface, the patina formation starts immediately, and the damaged zone is sealed-off from the atmosphere, preventing (creep) rust.

Specialty Steel Sheet offers you the original COR-TEN® A in a contemporary version, which also fully meets the requirements of S355J0WP according to EN 10025-5, with dual certificate according to EN 10204 3.1, with CE marking for S355J0WP, produced by SSAB in Sweden and Finland.

Longer lifespan, less maintenance, fully recyclable, it seems that the use of COR-TEN® can also contribute to sustainability.

Chemical composition

Below is the typical chemical composition of COR-TEN A / S355J0WP in %.

  C Si Mn P S Al Cu Cr Ni CEV
COR-TEN A / S355J0WP max. 0,12 0,25-0,75 0,20-0,50 0,07-0,15 max. 0,030 0,015-0,06 0,25-0,55 0,50-1,25 max. 0,65 0,35-0,39

Mechanical properties

Below are the typical mechanical properties of COR-TEN A / S355J0WP.

  Yield strength ReH (MPa) Tensile strength Rm (MPa) Impact toughness Elongation A50 (%) Bending radius 90o (min.)
COR-TEN A / S355J0WP 345 min. 485 min. min. 27 J bij 0oC 20 min. 2.0 x t
COR-TEN A cold rolled 310 min. 450 min. - 22 min. 0.5 x t

Delivery progam

Below you will find the COR-TEN A / S355J0WP range that we can deliver from stock. All dimensions in mm.

Thickness Width Length sheet or plate
  2.0 1500 3000 sheet, cold rolled
  3.0 1500 3000 sheet, hot rolled
  4.0 1500 3000 sheet, hot rolled
  5.0 1500 3000 sheet, hot rolled
  6.0 1500 3000 sheet, hot rolled
  8.0 1500 3000 sheet, hot rolled
  8.0 2000 4000 plate
10.0 1500 3000 plate
10.0 2000 4000 plate
12.0 2000 4000 plate

Other dimensions

In addition to standard dimensions from stock, we can also supply customized dimensions from new production. Cut-to-length sheet can be produced with a length of up to 16000 mm. Please feel free to inquire about the possibilities.


  • Thickness: cold rolled sheet EN 10131: 2006; hot rolled sheet 2/3 EN 10051: 2010; reversing mill plate 3/4 EN 10029: 2011.
  • Width: cold rolled sheet -0 / + 5mm; hot rolled sheet -0 + 20 mm; reversing mill plate -0 / + 10 mm.
  • Flatness: cold rolled sheet max. 6 mm / m; hot rolled sheet max. 3.0 mm / m; reversing mill plate max. 6 mm / m deviation.


COR-TEN A / S355J0WP comes with an EN 10204: 3.1 certificate by default, with CE Mark for S355J0WP.


COR-TEN A / S355J0WP can be processed in the same way as non-weather-resistant structural steel of comparable strength: cutting, shearing, bending, etc.


COR-TEN A / S355J0WP is phosphor-alloyed but is easy to weld. Make sure to use the correct welding consumables, for example ESAB OK Aristorod 13.26 with 0.5% copper (Cu) and 0.5% nickel (Ni).