L’Corten steel it is a material that allows you to combine efficiency and aesthetics. In fact, it has structural and aesthetic properties capable of responding to the needs of modern construction. And not only. It is in fact highly appreciated and used by artists and interior designers.
Resistant to atmospheric corrosion and mechanical stress, Corten is defined as a “living metal” due to its ability to self-regenerate.
Here is an in-depth guide on its features and fields of application.
Contents of this Page
1 Corten steel: what it is
- 1.1 Definition
- 1.2 Initials
- 1.3 History
2 Corten steel: characteristics and properties
- 2.1 Live metal
- 3 Corten steel: types
- 4 Corten steel: advantages
- 5 Disadvantages
- 6 Corten steel: uses and uses
7 Corten steel: architecture, design and communication
- 7.1 Architecture
- 7.2 Outdoor
- 7.3 Interior Design
- 7.4 Signs and Plates
- 8 Corten steel: how to recognize it
Corten steel: what it is
Corten steel is a steel with a low content of alloying elements:
- phosphorus 0.1-0.2%
- copper 0.2-0.5%
- chromium 0.5-1.5%
Patented in 1933 by the American company United States Steel Corporation (USS), it offers high mechanical strength and exceptional resistance to atmospheric agents.
Its peculiarity consists in the fact that its chemical composition allows to create a superficial rust layer which does not however alter the mechanical characteristics of the steel itself.
This layer of rust not only protects architectural artifacts from atmospheric agents, but represents a unique finish of its kind. Not surprisingly, it is in great demand and also used by artists and designers for their creations.
Last but not least, it is also a more eco-friendly material than traditional steel.
The term Corten derives from the abbreviation of the English terms that define the main characteristics:
- CORrosion restistance (corrosion resistance)
- TENsile strength
The most well-known abbreviations of corten steel are: Corten steel A / S355J0WP, often also called “phosphorus steel” (P), an element that favors oxidation for protective purposes.
It was the year 1933 when Corten steel was first heard of. In fact, in that year this material was patented by the United States Steel Corporation. Initially it began to be used in the field of mechanics, as a protective coating for freight carriages, tank cars and containers, especially for the transport of coal.
It was only in 1964 that its first important application as structural steel in the construction field took place, with the construction of the John Deere and Co Headquarters in Illinois, based on a project by architect Eero Saarinen.
Today Corten steel is used in various fields: construction, infrastructure but also art, design and communication.
Corten steel: characteristics and properties
The main and extraordinary characteristic of Corten steel lies in its ability to protect itself from electrochemical corrosion. In fact, during the natural oxidation process, the metal releases a powder of oxides of the alloy elements that create a surface patina consisting of a porous outer layer and a very thin and waterproof inner layer.
Under normal environmental conditions, this coating, of the typical rust color, forms over a period of about 18-36 months. The rust effect has a double value: aesthetic, but also protective.
Corten is also called “live metal” because, in the event that the surface patina is nicked or scratched, the oxidation process restarts to build a new protection.
The passive formation of this protective patina occurs under certain conditions:
- continuous dry / wet alternation
- direct contact with the atmosphere
- action of sunlight
- absence of permanent stagnation with water
- no contact or proximity to chlorides (e.g. sea water)
- no application of substances (paints, varnishes, waxes …) before the birth and formation of the protective oxide film
Corten steel: types
There are 3 types of Corten steel, each with its own characteristics and suitable for specific uses and design needs:
- Type A Corten steel o Corten with phosphorus, suitable for architectural applications. Compared to carbon steel it is 8 times more resistant to atmospheric agents
- Type B Corten steel o Corten vanadium, ideal for structural applications subjected to stress. It offers resistance to atmospheric agents 4 times higher than that of carbon steel
- Corten steel of Type C, similar to vanadium Corten, and therefore suitable for highly stressed structures
Corten steel: advantages
We summarize below the numerous advantages of Corten Steel:
- offers excellent structural resistance and resistance to atmospheric corrosion; with the passage of time the metal does not deteriorate but on the contrary, takes on a ‘lived’ aspect
- has a lower price than normal steels
- it is easy to clean, requires little maintenance
- extremely versatile as it lends itself to different types of processing (cutting, forging, drawing, bending, laser cutting, welding …)
- long lasting
- 100% recyclable as it is a natural material
Corten steel is not without its disadvantages; but compared to the pros, they are very few:
- its installation requires skilled labor
- when water ‘washes’ the surface, the steel releases iron ions which can cause reddish rust spots on adjacent surfaces
Corten steel: uses and uses
Corten steel is widely used in numerous sectors:
- Construction (load-bearing structures, walls, fences, fixtures …)
- Architecture, civil engineering, furniture
- Viability (infrastructure, road and rail bridges …)
- Storage (tanks, deposits …)
- Transport (trucks, trolleys, maintenance machines …)
Corten steel: architecture, design and communication
As already mentioned, due to its mainly aesthetic characteristics, it is widely used by architects and designers. There are numerous works carried out in Corten signed by the most famous architectural firms in the world.
Contemporary architects appreciate its particular color variation and the fact that it combines well with other materials. Without obviously forgetting more technical aspects such as resistance to atmospheric agents, the possibility of obtaining considerable reductions in thickness and, consequently, in weight.
More and more often it is not uncommon to find benches, litter bins, planters, bicycle racks… made with this material.
In recent years, designers and creatives have designed and created entire collections conceived both for street furniture and for setting up private outdoor spaces.
Corten is also very suitable for interior design applications. In particular, it goes very well with it industrial style. Green light therefore to furnishing accessories such as tables, chairs is libraries.
Signs and Plates
The peculiarities of Corten are also highly appreciated in the field of communication and advertising. Corten signs are in fact increasingly popular in both small and large urban centers.
Corten steel: how to recognize it
As is usually the case with everything successful, imitations and ‘fake’ versions of Corten steel are also produced.
There are basically three processes to reproduce the color of the material:
- Metallization: Corten steel is applied very thinly on a traditional carbon steel base. Although the aesthetics recalls Corten, since the base involves the risks of a classic steel, any type of damage to the surface layer can cause oxidation of the underlying metal with consequent formation of unstable rust and the probable detachment of the same.
- Painting: there are paints that reproduce the rust effect. Being an artificial layer, the surface always remains uniform
- Simple oxidation: the classic rust that forms on traditional iron has the appearance of the patina of corten, but causes the typical peeling effect of iron