What is Corten Steel?
Corten steel, also known as “weathering steel,” is a special type of steel alloy that doesn’t need painting or protective coatings. This makes it different from other types of steel. When exposed to the elements, Corten steel forms a rust-like layer on its surface, which actually protects it from further corrosion.
This innovative material was first developed in the 1930s for use in the railroad industry and was patented by U.S. Steel (USS). The name “COR-TEN” comes from its two key properties: “Cor” stands for Corrosion Resistance and “Ten” stands for Tensile Strength.
What is Corten Steel Made of?
Corten steel is mainly made from iron and a small amount of carbon. What makes it special are the unique alloying elements it contains: chromium, nickel, copper, and added phosphorus. These elements give Corten steel its self-protecting properties. One remarkable feature is that the outer layer of Corten steel can naturally repair itself if it gets scratched or damaged, showcasing its durability and long-lasting nature.
Is Corten Steel Weldable?
Yes, Corten steel is weldable and behaves similarly to other low-carbon steels like mild steel. However, depending on the specific application, a special filler material might be needed. With the proper equipment and tools, Corten steel can be welded and shaped to meet various requirements.
Is Corten Steel Expensive?
Corten steel products are generally about 50% more expensive than mild steel products. However, due to its longevity and low maintenance requirements, Corten steel is a worthwhile long-term investment. The higher initial cost is balanced by the reduced need for maintenance and replacement over time.
What is Special About Corten Steel?
Corten steel’s unique combination of alloys and its specific production method give it exceptional strength and corrosion resistance. Unlike other steels, Corten does not require painting, making it low-maintenance. The registered trademark for COR-TEN is held by U.S. Steel, and it is also produced under license by SSAB (Swedish Steel). These qualities make Corten steel a preferred choice for various applications, including planter design and architectural projects.
How Does Corten Steel Weather?
Corten steel undergoes a unique weathering process that usually takes 6-9 months, influenced by the surrounding weather conditions. Initially, the steel develops an orange patina. Over time, this patina transforms into a darker brown color, giving Corten steel its distinctive appearance. To form this protective layer effectively, Corten steel needs alternating wet and dry conditions.
- Step 1 – Initial Stage : When newly created, Corten steel has a dark, oily coating on its surface.
- Step 2 – Beginning of Weathering : The dark coating begins to degrade, initiating the weathering process.
- Steps 3 & 4 – Run-Off Phase : During this phase, which lasts between 3 to 9 months depending on weather conditions and location, the steel experiences “run-off.”
- Steps 5 & 6 – Final Phases : In these final stages, occasional run-off may still occur. The patina on the Corten steel continues to develop, achieving a more uniform and striking appearance.
How is Corten Steel Made?
Corten steel is exclusively produced in sheet form, which sets it apart from other types of steel like mild steel that are available in various shapes and forms. This specialized production process contributes to Corten steel’s unique properties and market position, although it can make the material less accessible compared to other steels.
Where is Corten Steel Used?
Corten steel’s unique properties make it popular across various industries, including architecture, construction, and landscaping. It is often seen in large structures like bridges and famous sculptures such as the Angel of the North. However, its use isn’t limited to grand projects. In recent years, Corten steel has become a favorite for outdoor garden products like steel planters, artwork, edging, water features, and street furniture, bringing a natural and rustic look to any outdoor space.
Understanding Run-Off in Corten Steel
A key aspect of Corten steel’s weathering process is the occurrence of ‘run-off.’ Run-off refers to the rusty water that can drain off from Corten steel, potentially staining the surfaces it contacts.
To prevent run-off from causing issues, consider the following steps:
- Complete Weathering Before Placement: Allow the Corten steel to fully weather before placing it in its final location. For a faster process, you can apply a weathering treatment to accelerate this transition.
- Use a Protective Layer: Place the Corten steel product on a slab or another protective material that can be moved or replaced once the weathering is complete. This barrier will protect your surfaces from staining.
- Opt for Easily Replaceable Materials: Position the Corten steel on grass, soil, or loose materials like stone, slate, or wood chippings. These materials can be easily turned over or replaced to eliminate any run-off stains.
What is the Thickness of Corten Steel?
The thickness of Corten steel varies based on its type:
- Corten A: Typically produced as a coil or sheet, with a thickness ranging from 1 mm to 12 mm.
- Corten B: Commonly produced as a plate, with a thickness ranging from 15 mm to 50 mm.
What is the Lifespan of Corten Steel?
Corten steel is known for its durability and long lifespan. For most environments and applications, Corten steel with a thickness of 2.0 mm or 3.0 mm can last over 25 years. To ensure longevity of more than 40 years, an additional 1.0 mm thickness is recommended to mitigate material loss over time. This makes Corten steel a reliable and long-lasting material choice for various projects.
What is the Price of Corten Steel in India?
The price of Corten steel sheets in India typically ranges from Rs 80 per kg to Rs 100 per kg. For an exact quote and the best possible deal, you can contact suppliers like Corten Steel Tube.
What is an Alternative to Corten Steel?
Powder-coated steel, mild steel, and galvanized steel are excellent alternatives to Corten, offering durability and various finishes to suit different needs.
Looking to Add Corten Steel to Your Outdoor Area?
Corten steel stands out thanks to its unique characteristics and numerous benefits. Its superior corrosion resistance, robust tensile strength, and cost-effectiveness over time make it ideal for various projects. Whether you’re considering a landscape feature, a statement artwork piece, or practical street furniture, Corten steel offers an unbeatable blend of durability, aesthetic appeal, and practicality.
We invite you to browse our extensive range of Corten steel products and envision how this unique material can enhance your next project. For any questions or further information, please contact our friendly team today!