Содержание
Кортеновая сталь: Марки, свойства, применение и технологические процессы
- Джон
Corten steel, known for its natural patina and durability, combines functionality, aesthetic appeal, and sustainability, making it a key material in modern architecture and engineering.
This article delves into the essence of Corten steel, exploring its definition, properties, grades, and applications. We also offer an overview of its history and processing techniques to help you learn more about it.
What Is Corten Steel?
Corten steel, or weathering steel, is a low-alloy steel that forms a protective rust-like patina, ensuring natural corrosion resistance. Named for “CORrosion resistance” and “TENsile strength”, it was trademarked by U.S. Steel in the 1930s. Key standards include ASTM A242 (Corten A, for architectural use), ASTM A588 (Corten B, for structural applications), and ASTM A606.
Its key feature is a stable patina from alloying elements like copper and chromium, halting further rusting. Durable and visually striking, it is widely applied in facades, bridges, sculptures, and industrial projects.
Corten Steel Texture
Corten steel develops a rough, organic texture as its rust-like patina forms over time. The surface starts smooth but becomes coarse and matte as the protective oxide layer stabilizes, creating a distinct industrial look that also prevents further corrosion.
The texture varies with environmental conditions. In wet-dry cycles, the patina is fine and uniform, while humid or polluted areas create rough, irregular surfaces.
Additionally, surface treatments like sandblasting create more even textures, while untreated surfaces develop natural patterns.
Is Corten Steel Expensive?
Corten steel is more expensive than mild steel due to its weathering properties and durability. However, its low maintenance and long lifespan often offset the higher initial cost, especially in outdoor applications.
The price also depends on the thickness, grade, and supplier, with thinner sheets like ASTM A606 often being more affordable than structural grades like ASTM A588.
History Of Corten Steel
- 1930s
Corten steel was developed by U.S. Steel as a high-strength, corrosion-resistant material for industrial use, originally branded as “Corten” to highlight its коррозионная стойкость и tensile strength.
- 1940s-1950s
Initially used in railway cars and coal hopper wagons due to its durability and reduced maintenance costs compared to painted steel.
- 1960s
Gained recognition in architecture, with pioneering projects like the John Deere Headquarters by architect Eero Saarinen, showcasing its unique patina and structural capabilities.
- 1970-е
Widely adopted for bridges and public infrastructure, particularly in the U.S., due to its ability to withstand weathering without protective coatings.
- 1980s-1990s
Expanded into global markets, especially in Europe and Asia, becoming popular in modern architectural designs for its raw, industrial aesthetic.
- 2000s-Present
Corten steel remains a favorite for sustainable design, used in facades, sculptures, and landscaping, valued for its evolving patina and low environmental impact.
What Grade Is Corten Steel?
The table below provides the corresponding grades of Corten steel under ASTM, EN, and GB/T standards, along with their specified product categories.
| Стандарт | Оценка | Product Category |
| ASTM A242 | Corten A | Decorative/Non-Structural |
| ASTM A588 | Corten B | Structural/Load-Bearing |
| ASTM A606 | А606 | Lightweight Architectural |
| EN 10025-5 | S355J0WP | Decorative/Structural |
| S355J2W | ||
| GB/T 4171 | Q235NH | Flexible Decorative/Industrial |
| Q355GNH | ||
| Q450NQR1 |
Corten Steel Properties
Chemical Composition of Corten Steel
| Элемент | С | Мн | Си | П | С | Cu | Кр | Ни |
| Corten A | ≤ 0,12 | 0.20 – 0.50 | 0.25 – 0.75 | 0.07 – 0.15 | ≤ 0,03 | 0.25 – 0.55 | 0.50 – 1.25 | ≤ 0,65 |
| Corten B | ≤ 0.19 | 0.30 – 0.65 | 0.15 – 0.50 | ≤ 0,04 | ≤ 0,03 | 0.20 – 0.40 | 0.40 – 0.65 | ≤ 0,45 |
Физические свойства Of Corten Steel
| Свойство | Метрический | Империал |
| Плотность | ~7.85 g/cm³ | ~0.284 lb/in³ |
| Температура плавления | ~1,500°C | ~2,732°F |
| Теплопроводность | ~40 W/m·K | ~23 BTU/h·ft·°F |
| Тепловое расширение | ~12 x 10⁻⁶ /°C | ~6,7 x 10⁻⁶ /°F |
| Электропроводность | ~6-7% IACS | ~6-7% IACS |
| Магнитные свойства | Ферромагнитный | Ферромагнитный |
Механические свойства Of Corten Steel
| Свойство | Метрический | Империал |
| Предел прочности | 480–630 MPa | 69.6–91.4 ksi |
| Предел текучести | ≥ 345 MPa | ≥ 50 ksi |
| Твёрдость по Бринеллю (HB) | ~160–180 | ~160–180 |
| Твердость по Роквеллу (HRC) | ~10–15 | ~10–15 |
| Твёрдость по Виккерсу (HV) | ~170–190 | ~170–190 |
| Удлинение | ≥ 20% (thickness ≤ 3mm) | ≥ 20% (thickness ≤ 0.12 in) |
| Модуль упругости | ~200 ГПа | ~29,000 ksi |
Corten Steel Characteristics
Superior Weathering Resistance
Corten steel contains copper, which helps form a dense, protective rust layer known as copper patina. This layer significantly slows down the oxidation process, providing a strong barrier against further corrosion. Chromium and nickel further enhance the steel’s resistance to rust, making it more durable in tough weather conditions.
Corten also has a self-healing ability. If the protective patina is damaged, exposure to air and moisture allows the steel to naturally regenerate the copper patina, preventing further rusting and ensuring long-lasting protection.
Low Maintenance Requirements
The self-healing property allows it to regenerate its protective oxide layer, preventing further corrosion without the need for frequent maintenance. Combined with its long-lasting durability, the ability is ideal for use in challenging environments like bridges, facades, and industrial structures.
High Strength and Durability
Corten steel has high strength and a tough microstructure, which allows it to perform well under cyclic loading (repeated stress). It can withstand heavy loads, resist fatigue, and endure environmental wear, making it ideal for infrastructure exposed to traffic, wind, and other environmental stresses.
How Long Does Corten Steel Last?
Corten steel lasts 50+ years in outdoor conditions due to its self-healing patina, depending on exposure to the environment.
Distinctive Aesthetic Appeal
Its surface not only has a unique aesthetic but also gains resilience over time, thanks to the formation of the protective oxide layer. As the material continues to weather, the rust stabilizes and transitions to a more consistent deep reddish-brown or bronze tone. This signature appearance is often desired in architectural designs, sculptures, and landscaping elements.
Sustainability and Environmental Benefits
Corten steel is a sustainable choice due to its extended lifespan and recyclability. The weathering process reduces the need for coatings, and the material can be recycled at the end of its life. This makes it a low-impact option for green building projects.
What Are The Disadvantages Of Corten Steel?
Complex Processing Requirements
Corten steel is heat-sensitive due to its high copper content. In processes like welding or cutting, excessive heat can cause the copper-rich layer to deteriorate, compromising the integrity of the protective patina.
Therefore, it is crucial to use the correct cutting methods and perform proper edge treatment. Welding requires preheating and post-weld treatment to prevent issues like cracking and ensure uniform rusting. Additionally, if the filler material used in welding does not match the weathering rate, gaps may form in the protective copper layer.
Slow Patina Formation
Corten steel takes time to develop its protective copper-green patina, and the rate at which it forms depends on environmental factors such as moisture, oxygen, and pollutants. During the early stages of oxidation, the patina may appear uneven, offering limited protection.
In areas with low pollution or insufficient moisture, if the formation of the patina is significantly slower than expected, urgent structural reinforcement or galvanization may be required.
How To Rust Corten Steel?
Expose Corten steel to moisture and oxygen. To speed up rusting, spray it with water or a saltwater solution.
SteelPro Group offers surface treatment options for corten steel products, helping you quickly achieve the desired rust effect for your projects.
Not Suitable for Certain Environments
While Corten steel excels in many outdoor applications, it is not recommended for the following environments:
- Excessive and Continuous Moisture
Corten steel is not inherently rust-resistant. Continuous moisture can prevent the protective patina from forming, leading to ongoing corrosion. In humid subtropical climates, Corten steel can cause surface degradation and rusting.
- High Salt Environments
Salt, such as from seawater or de-icing salts, can penetrate the patina, causing pitting and accelerated corrosion. Marine environments or areas with frequent salt exposure are better suited for stainless steel or other corrosion-resistant materials.
High Initial Cost
Corten steel is generally more expensive than standard carbon steel due to its alloying elements (copper, chromium, nickel) and the specialized manufacturing process. This higher upfront cost can be a drawback for projects with tight budgets.
Staining and Environmental Impact
In the early stages of exposure, Corten steel can exhibit bleeding, causing stains surrounding surfaces, like concrete or wood, with rusty streaks. Additionally, runoff from Corten steel can cause staining of nearby surfaces, particularly in areas with high rainfall.
What Is Corten Steel Used For?
In essence, Corten steel is used for projects where a combination of long-term durability, distinctive visual appeal, and low maintenance are essential. It excels in architectural, structural, and artistic applications.
| Промышленность | Конкретные приложения |
| Архитектура | Facades, cladding, canopies, shade structures, and ornamental gates. |
| Инфраструктура | Bridges, highways, and structural components are exposed to environmental stress. |
| Art & Sculpture | Outdoor sculptures and landscape art. |
| Landscaping & Urban Design | Retaining walls, garden features, and fencing. |
| Public & Commercial Spaces | Railings, signage, and exterior elements in public spaces. |
Process Of Corten Steel
Casting and Rolling
Corten steel is produced in large steel mills. The alloy is cast into billets, which are then hot-rolled into plates, sheets, or coils, depending on the required form.
Welding and Fabrication
Corten steel is cut, welded, and fabricated using weathering steel-compatible techniques to maintain its corrosion resistance.
- Preheating and post-weld treatment are essential to minimize the risk of cracking in Corten steel. Additionally, using the correct filler material ensures the welded joints maintain the alloy composition and corrosion resistance.
- For cutting, techniques like oxygen-acetylene cutting, plasma cutting, and laser cutting are used, followed by edge finishing to ensure smooth surfaces that promote uniform development of the protective patina.
Patina Formation
Exposure to moisture and oxygen triggers the formation of a protective, reddish-brown oxide layer that prevents further corrosion.
To speed up the rusting process, surface treatments like acid washes, saltwater sprays, or humidity chambers can be used. These techniques can help achieve a full patina in a shorter period.
Surface Treatment and Inspection
After patina formation, a final inspection is done, and optional protective coatings may be applied to enhance durability in harsh environments.
Delivery and Installation
The steel is delivered, installed, and continues to develop its patina, providing a long-lasting, visually unique appearance.
Need Corten Steel For Your Next Project?
SteelPro Group offers corten steel products such as ASTM A242, ASTM A588, and ASTM A606. Our range includes weathering steel plates, coils, angles, beams, and more. We can also offer custom services like:
- Accelerated patina treatment or pre-rusted Corten steel options
- Custom cutting and sizing
- JIT (Just-in-Time) delivery
- Доставка по всему миру
As an experienced Corten steel supplier, SteelPro Group guarantees that the products you receive have consistent quality and minimal tolerances. If you have any requirements or inquiries, feel free to contact us for a quote or to discuss your solutions!
