Corten steel, sometimes written with a hyphen as COR-TEN steel, is one of the industrial metal materials used for various purposes. This material is also referred to as weathering steel. A group of alloys was developed to eliminate the painting requirements and form a stable rut-like look after several years of exposure to different weather conditions. The name Corten refers to the two distinctive properties of this type of metal, including corrosion resistance and tensile strength. The original material received the regulation destination A242 (Corten A) from the international standard group. However, newer and more modern ASTM grades are A588 (Corten B), and A606 is for thin sheet metals. All of the COR-TEN steel alloys are in common utilization and production. Oxidation of Corten steel surfaces takes about six months. However, surface treatments generally accelerate the oxidation occurring to as little as two hours.

History of COR-TEN

The development of Corten steel goes back to 1933. In that year, the United States Steel Corporation produced and patented a metal substance with significant mechanical resistance, primarily used to develop railroad hopper cars. These specific cars were meant to handle heavy bulk loads such as coal, metals, and other mineral grain and products. The controlled corrosion property of COR-TEN steel made the material popular among industrial manufacturers, and soon after discovering its benefits, USS applied the trademarked name of Corten. Due to inherited toughness, this metal substance is still utilized for storage containers and building materials and cladding systems.

Properties of Corten Steel

Weathering characteristics of Corten Steel refers to the chemical composition of this substance, allowing it to exhibit better resistance to atmospheric corrosion compared to other steel materials. This is due to the protective layer formed on its surface under the influence of weather conditions.

The corrosion retardant property of the protective layer of Corten steel is generated by the particular distribution and concentration of alloying elements existing in its structure. The protection layer on the surface regenerates and develops continuously when exposed to external weather conditions. In simple terms, the steel is meant to rust to generate the protecting coating for the cladding materials or other decorative products.

Manufacturers develop the Corten steel featuring different mechanical properties. These properties of COR-TEN steel are as follows:

ASTM A242: The original A242 steel alloy features a yield strength of 340 megapascal and ultimate tensile strength of 480 megapascals for light-medium rolled plates and shapes to 19 millimeters thickness. Additionally, it has a yield strength of 320 megapascals and maximum strength of 460 MPa for medium weight rolled plates from 19 to 25 millimeters thick. Moreover, the thickest rolled plates and sections, which are 38 to 102 mm thick, feature a yield strength of 290 MPa and maximum strength of 430 MPa. The ASTM A242 is classified into two different types. Each one is suitable for particular projects. The first type is suitable for cladding systems, constructions, housing structures, and cars. On the other hand, the second type of steel is perfect for urban finishing, passenger ships and cranes.

ASTM A588: The second standard alloy known as ASTM A588 features a yield strength of at least 340 megapascals and ultimate tensile strength of 480 MPa for all plate thicknesses up to 100mm. Plates that are manufactured in 102 to 127mm thickness involve lower yield and maximum tensile strength. Additionally, Corten steel sheets are available in 127 to 203mm thickness that has a yield strength of 290 MPa and the ultimate strength of at least 430 megapascals.

Applications and Usage

Corten steel is a suitable material for a variety of outdoor projects. One of the most current applications of these materials is for creating perforated decorative panels, which are widely used for both coverings and interior areas. Another practice of these materials is for producing sculptures for a city. This is because the substance quickly develops its layer of rust and protects the statue from rain and humidity, giving it a weathered effect. Additionally, cities can benefit from COR-TEN steel in their bridges and other structures that require protecting coating for their exterior. Small projects such as domestic gardens also can benefit from the material. In this case, perforated panels are the perfect decorative products. However, it is often the chosen alternative when a concrete wall unit does not fit and overwhelms the rest of the garden’s area. Other materials made from this substance include cycle hoops, tree grilles and planters for shrubs and brushes. However, there are other alternatives for these materials when it comes to creating cladding materials for constructions, such as ACM panels (aluminum composite panels) which are also corrosion resistant and feature lightweight and modern characteristics.