Corten Steel, also known as weathering steel, is a type of steel alloy specifically created for outdoor use. It forms a protective rust layer when exposed to the elements, eliminating the need for painting. Over time, this rust layer acts as a shield, helping to preserve the underlying metal from further corrosion.
Corten Steel Features
Weather Resistance
Corten Steel is highly resistant to rust, eliminating the need for painting. This feature not only reduces maintenance costs but also provides a distinctive, earthy appearance as the protective rust layer forms. Depending on the specific grade and environment, Corten Steel can offer 4-8 times more weather resistance than regular steel.
Paint Durability
Corten Steel can be painted like standard steel, but its inherent rust-resistance ensures that even if the paint deteriorates, the spread of rust is minimized. This extends the paint’s lifespan and reduces the need for frequent repainting.
Weldability
With its low carbon content and added alloying elements like copper and chromium, Corten Steel is easy to weld. It supports various welding techniques, including manual welding, gas-shielded welding, and submerged arc welding. Even thin-gauge Corten Steel can be spot welded.
Workability
Corten Steel is as workable as other steels of similar strength, allowing it to be easily bent, shaped, and cut.
Reliability
Since its introduction in 1959, over 2.6 million tons of Corten Steel have been produced, proving its reliability and widespread use.
Uses of Corten Steel
Garden and Landscape Design:
Corten Steel is a popular choice for outdoor spaces, used in planter boxes, landscape edging, and more. Its natural, weathered appearance has made it a top trend in landscape design, as highlighted by The Wall Street Journal.
Roofing and Siding:
Weathering steel, especially in corrugated and profile panels made from ASTM A606-4 and A588, is commonly used for roofing and building walls. For example, the exterior walls of the Kalpataru Piping Solutions office building were constructed using cold-rolled Corten steel panels.
Sign Posts:
Corten steel sign posts are designed to last up to 30 years longer than regular steel posts due to their protective patina. These rust-resistant posts are often used for traffic signs and to mark vineyard rows, blending seamlessly with outdoor environments.
Security Solutions:
Corten steel is ideal for gates, fences, and bollards, providing both security and aesthetic appeal. The rusty patina naturally integrates with outdoor settings like playgrounds, parks, farms, and vineyards.
Outdoor Sculptures:
Corten steel is increasingly popular for outdoor sculptures. Artists appreciate its corrosion resistance, ease of fabrication, and unique appearance, which adds visual interest to public and private spaces.
Following Standard & Specifications of corten steel
| Steel grade | Designation | Applicable thickness range (mm) | Feature | Main applications |
|---|---|---|---|---|
| Highly weathering steel product | COR-TEN O | Hot-rolled sheet and plate: 1.6≤t≤76 Cold-rolled sheet: 0.4≤t≤2.3 Shape: 6≤t≤38 Bar: 5.5≤t≤44 | Because of its high weather resistance, this grade is most suitable for unpainted application. | Sash, panel, and other building exterior members Outer plate for rolling stock Marine container Steel tower |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN 490A/B/C | Hot-rolled sheet and plate: 6≤t≤50 Shape: 6≤t≤38 | Because of its high weather resistance, this grade can be used without painting. Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN 570 | Hot-rolled sheet and plate: 6≤t≤50 | Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| General weathering steel product | NAW™ 400 | Hot-rolled sheet and plate: 1.6≤t≤12.7 Shape: 3.2≤t≤12.7 | Featuring economical advantage, this grade is recommended for use with painting. | Column, beam, and outer plate of container Ready-mixed concrete car Small-capacity compressor Water tank |
| General weathering steel product | NAW™ 490 | Hot-rolled sheet and plate: 1.6≤t≤12.7 Cold-rolled sheet: 0.4≤t≤2.3 Shape: 3.2≤t≤12.7 | Because of its high strength, NAW 490 offers a high wear abrasion resistance. | Column, beam, and outer plate of container Ready-mixed concrete car Small-capacity compressor Water tank |
| Ni-type highly weathering steel product | NAW-TEN™12 -400A/B/C -490A/B/C -570 | Hot-rolled sheet and plate: 6≤t≤100 | Because of its high weather resistance, this grade is most suitable for unpainted application. Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. The mechanical properties excluding chemical composition conform to those in JIS SMA standards. | Bridge Steel tower Building exterior member |
| Ni-type highly weathering steel product | NAW-TEN™15 -400A/B/C -490A/B/C -570 | Hot-rolled sheet and plate: 6≤t≤100 | Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel tower Building exterior member |
| Highly weathering steel product | COR-TEN A | t≤12.7 | Because of its high weather resistance, this grade is most suitable for unpainted application. | Sash, panel, and other building exterior members Outer plate for rolling stock Marine container Steel tower, etc. |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN B | t≤200 | Because of its high weather resistance, this grade can be used without painting. Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN B-QT | t≤100 | Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN C | t≤25 |
Corten Steel Chemical Composition
| Steel grade | Designation | Applicable thickness range (mm) | Feature | Main applications |
|---|---|---|---|---|
| Highly weathering steel product | COR-TEN O | Hot-rolled sheet and plate: 1.6≤t≤76 Cold-rolled sheet: 0.4≤t≤2.3 Shape: 6≤t≤38 Bar: 5.5≤t≤44 | Because of its high weather resistance, this grade is most suitable for unpainted application. | Sash, panel, and other building exterior members Outer plate for rolling stock Marine container Steel tower |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN 490A/B/C | Hot-rolled sheet and plate: 6≤t≤50 Shape: 6≤t≤38 | Because of its high weather resistance, this grade can be used without painting. Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN 570 | Hot-rolled sheet and plate: 6≤t≤50 | Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| General weathering steel product | NAW™ 400 | Hot-rolled sheet and plate: 1.6≤t≤12.7 Shape: 3.2≤t≤12.7 | Featuring economical advantage, this grade is recommended for use with painting. | Column, beam, and outer plate of container Ready-mixed concrete car Small-capacity compressor Water tank |
| General weathering steel product | NAW™ 490 | Hot-rolled sheet and plate: 1.6≤t≤12.7 Cold-rolled sheet: 0.4≤t≤2.3 Shape: 3.2≤t≤12.7 | Because of its high strength, NAW 490 offers a high wear abrasion resistance. | Column, beam, and outer plate of container Ready-mixed concrete car Small-capacity compressor Water tank |
| Ni-type highly weathering steel product | NAW-TEN™12 -400A/B/C -490A/B/C -570 | Hot-rolled sheet and plate: 6≤t≤100 | Because of its high weather resistance, this grade is most suitable for unpainted application. Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. The mechanical properties excluding chemical composition conform to those in JIS SMA standards. | Bridge Steel tower Building exterior member |
| Ni-type highly weathering steel product | NAW-TEN™15 -400A/B/C -490A/B/C -570 | Hot-rolled sheet and plate: 6≤t≤100 | Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel tower Building exterior member |
| Highly weathering steel product | COR-TEN A | t≤12.7 | Because of its high weather resistance, this grade is most suitable for unpainted application. | Sash, panel, and other building exterior members Outer plate for rolling stock Marine container Steel tower, etc. |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN B | t≤200 | Because of its high weather resistance, this grade can be used without painting. Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN B-QT | t≤100 | Because of its high weldability and notch toughness, this grade is recommended for use for welded structures. | Bridge Steel frame, steel tower, various platforms Crane and other industrial machinery Flood gate Low-pressure gas holder, water tank, and other large-size vessels |
| Unpainted specifications For welded structures Weathering steel product | COR-TEN C | t≤25 |
Types of COR-TEN Steels
There are two main types of COR-TEN steel: COR-TEN A and COR-TEN B. The key difference between these types lies in their phosphorus content.
- COR-TEN A: Typically produced as sheets or coils, COR-TEN A is commonly used in cladding and ductwork.
- COR-TEN B: Usually made as plates, structural sections, or tubes, COR-TEN B is favored for more heavy-duty applications.
The weather resistance of COR-TEN steel comes from the patina, a protective oxide layer that forms on the surface. This patina is dense and nearly impermeable to oxygen due to the steel’s alloying elements. Under typical weather conditions, the patina develops over 18 to 36 months, starting as a reddish-brown color and gradually darkening.
Patina formation occurs faster and results in a darker color in industrial environments compared to rural areas. However, in marine environments where the air contains high levels of chlorides, the patina’s formation can be hindered, compromising the steel’s protective qualities. Therefore, COR-TEN steel is not recommended for use near the sea or in chloride-rich areas. For open-air structures, the slow corrosion rate is accounted for by adding extra material thickness to accommodate any potential loss over time.
Advantages of COR-TEN Steel
COR-TEN steel, known for its exceptional resistance to atmospheric corrosion, is widely used in various structural and architectural applications like bridges, open-frame buildings, transmission poles, and sculptures. It also performs well at high temperatures, making it suitable for flues, chimneys, and ducting. Here are some key benefits of COR-TEN steel:
- Low Maintenance
COR-TEN steel is ideal for structures in hard-to-reach or dangerous locations where future maintenance needs to be minimized. It requires only periodic inspection and cleaning to maintain its performance.
- Cost Efficiency
Although COR-TEN steel may have a slightly higher material cost, it doesn’t require protective coatings or paints, leading to overall savings. For instance, weathering steels can be about 5% cheaper than traditional painted steel options in bridge construction.
- Reduced Lifetime Costs
With minimal maintenance requirements, COR-TEN steel significantly lowers the costs associated with upkeep and reduces indirect costs like traffic disruptions in bridge applications.
- Faster Construction
Since COR-TEN steel doesn’t need to be painted on-site or in a fabrication shop, construction processes can proceed more quickly.
- Aesthetic Appeal
The unique, evolving appearance of COR-TEN steel often blends harmoniously with natural surroundings, enhancing its visual appeal over time.
- Environmental Benefits
Using COR-TEN steel eliminates the need for blast cleaning and the use of paints containing volatile organic compounds (VOCs), making it an eco-friendly option.
High-Temperature Performance
COR-TEN steel forms a protective patina at temperatures above 400°C, which can delay oxidation. This allows COR-TEN steel to withstand higher temperatures—up to 50°C more than typical carbon-manganese steels—although it is not recommended for load-bearing applications above 450°C.
Corten Steel & Applications
| Acoustical Panels | Buses | Door (Water-cooled) | Open Bridge Deck | Ski-tow Towers | Tanks |
| Agricultural Equipment | Cable Guards | Exhaust Fans – Industrial | Outdoor Signboard Supports | Snow Plow Parts | Towboats |
| Air Conditioning Equipment | Cable Trays | Flash Chamber – Evaporators | Outside Storage Racks | Spray Dryers | Traffic Signal boxes/Lights |
| Airport Runway Lights | Cladding | Floor Parts | Pipe – Structural | Stack/Stacks Liners | Transformer Shells |
| Air Pre heaters | Concrete Forms | Frame Expansion Joints | Pole Line Hardware | Stack Regulators | Transmission Towers |
| Amusement Park Rides | Containers | Door (Water-cooled) | Pollution Control Equipment | Stairs and Handrails | Trash barrels |
| Auto Transport Loading Ramps | Conveyors | Door (Water-cooled) | Pontoons/Pontoon Grating | Steam-generating Apparatus | Trenching Machinery |
| Baghouse Dust Collectors | Dams and Locks | Exhaust Fans – Industrial | Pumps and Pump Parts | Storage Containers | Trolley Cars |
| Bins | Derricks | Flash Chamber – Evaporators | Railroad Rolling Stock | Stove Parts | Trucks |
| Blast Plates | Ductwork | Floor Parts | Open Bridge Deck | Structural Conveyor Tubes | Tubing – Mechanical |
| Blowers | Electric Dust Precipitators | Ladders | Railroad Signal Towers and Boxes | Tanks | Ventilation Louvers |
| Bolts and Nuts | Earth-moving Equipments | Light Standards | Rakes – Classifier | Towboats | Wheelbarrows |
Corrosion
Corrosion is the process by which construction materials, like steel, deteriorate due to chemical or electrochemical reactions with their environment. This natural process affects all materials, but in steel, it manifests as rust. The rate and extent of rusting in steel depend on factors such as its chemical composition, environmental conditions, structural design, and proper construction practices. Weathering steels, like COR-TEN, are specifically alloyed with small amounts of chromium (Cr), nickel (Ni), copper (Cu), and phosphorus (P) to enhance their resistance to corrosion.
FAQs
What is cor ten steel used for?
Corten steel is widely used in architecture, construction, and landscape design due to its weather-resistant properties. It is commonly employed in large infrastructures like bridges, building facades, and outdoor sculptures, including the famous Angel of the North. Its unique appearance and durability make it a popular choice for both functional and aesthetic applications.
What is Cor 10 material?
Cor-Ten is the trade name for a group of weathering steel alloys developed by the United States Steel Corporation (USS). These steels are designed to offer higher strength and longer life cycles, particularly in outdoor applications. When exposed to the elements, Cor-Ten forms a protective layer of rust, known as patina, which helps prevent further corrosion, making it ideal for structures that require durability and minimal maintenance.
What grade of steel is corten?
The original COR-TEN® received the ASTM standard designation A242 (“COR-TEN® A”). Newer grades include A588 (“COR-TEN® B”) and A606 for thin sheet applications. These grades offer excellent corrosion resistance.
