What is A588 AR Corten Wtahering Steel Plate?
A588 high-strength low-alloy structural steel (HSLA) is a weathering steel produced in accordance with ASTM standards, designed for excellent atmospheric corrosion resistance. Its chemistry is carefully engineered with alloying elements such as copper (Cu 0.20–0.40%), chromium (Cr 0.40–0.65%), and nickel (Ni 0.25–0.50%), enabling the formation of a dense, protective patina layer in natural environments, which significantly improves corrosion resistance.
The atmospheric corrosion resistance of A588 steel is approximately 4–8 times higher than that of plain carbon steel, allowing long-term use without coating and reducing maintenance costs.
Its minimum yield strength is about 345 MPa, with a tensile strength of approximately 485–620 MPa. Compared with A36 steel, the strength is increased by about 35–40%, providing a superior strength-to-weight ratio.
We supply A588 steel in plates, sections, and coils. It is compatible with common welding processes such as SMAW, GMAW, and SAW. A588 steel is typically supplied in hot-rolled or thermomechanically controlled processed (TMCP) condition, with thickness ranging from about 3–100 mm, offering a wide specification range suitable for cutting, bending, drilling, and complex structural fabrication.
We can provide various steel processing services, all completed using professional equipment with corresponding processes.
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Plasma Cutting is carried out using plasma cutting machines, suitable for fast cutting and rough processing of medium and thick steel plates, offering high efficiency and strong adaptability.
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Laser Cutting is performed with fiber laser cutting machines, enabling high-precision cutting and complex shape processing with smooth edges and minimal tolerance.
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CNC Bending is completed using CNC press brake machines, which precisely control bending angles through a digital system to ensure consistent and accurate forming results.
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Welding is carried out using CO₂ gas shielded welding and manual arc welding equipment, used for structural steel joining and assembly, ensuring strong and reliable connections.
With its high strength, weather resistance, and low maintenance advantages, A588 steel is widely used in bridges, building structures, and outdoor heavy-duty engineering applications exposed to long-term atmospheric conditions.
ASTM A588 Corten Steel Plate Specification
| Project | Pacameter |
|---|---|
| Forms | Steel plates, Corten steel plate, mild steel sheet, carbon steel plates |
| ASTM Standard | ASTM A588 |
| Material Chart | A588 Grade A,B,C,K |
| Thickness | 0.3–200 mm |
| Width | 10–3500 mm |
| Length | 2 m, 2.44 m, 3 m, 6 m, 8 m, 12 m, or customized / rolled |
| Surface | PE coated, black painted, anti-rust varnished, galvanized, color coated, anti-rust oiled, checkered, etc. |
| Factory Scale | Integrated steel processing plant with cutting, forming, welding and surface treatment lines |
| Monthly Output | 8,000–15,000 tons/month (depending on specification) |
| Delivery Time | 7–15 days (standard orders), 15–25 days (customized / large projects) |
ASTM A588 corten steel plate chemical composition
| ASTM A588 | A588 grade A | A588 grade B | A588 grade C | A588 grade K |
| C | ≤ 0.19 | ≤0.20 | ≤0.15 | ≤0.17 |
| Mn | 0.80-1.25 | 0.75-1.35 | 0.80-1.35 | 0.50-1.20 |
| P | ≤0.04 | ≤0.04 | ≤0.04 | ≤0.04 |
| S | ≤0.05 | ≤0.05 | ≤0.05 | ≤0.05 |
| Si | 0.30-0.65 | 0.15-0.50 | 0.15-0.40 | 0.25-0.50 |
| Ni | ≤0.40 | ≤0.50 | 0.25-0.50 | ≤0.40 |
| Cr | 0.40-0.65 | 0.40-0.70 | 0.30-0.50 | 0.40-0.70 |
| Mo | - | - | - | ≤0.10 |
| Cu | 0.25-0.40 | 0.20-0.40 | 0.20-0.50 | 0.30-0.50 |
| V | 0.02-0.10 | 0.01-0.10 | 0.01-0.10 | - |
| Nb | - | - | - | 0.005-0.50 |
ASTM A588 corten steel plate mechanical properties
| ASTM A588 | ASTM A588 corten steel plate thickness | ||
| ＜100mm | ≥100-125mm | ＞125-200 | |
| Tensile strength min MPa | 485 | 460 | 435 |
| Yield strength min MPa | 345 | 315 | 290 |
| Elongation min | 21 | 21 | 21 |
A588 Weathering Steel Plate Surface
| Surface Type | Surface Description | Roughness / Technical Specification |
|---|---|---|
| HR (Hot Rolled) | Hot-rolled as-rolled surface. The steel plate retains its original mill finish with a dense dark gray or black iron oxide scale. Since no further treatment is applied, the surface may show slight scratches or color variation during transportation. | Ra 6.3 – 12.5 μm (relatively rough surface) |
| SP (Shot Blasted / Pickled) | Shot blasted or acid pickled descaled surface. The oxide scale is completely removed by blasting (Sa2.5 grade) or chemical pickling, revealing a clean metallic silver-gray finish. This surface is an ideal base for artificial weathering or coating. | Ra 3.2 – 6.3 μm (provides excellent roughness for rust layer adhesion) |
| RP (Pre-rusted / Accelerated Weathered) | Pre-rusted surface via accelerated weathering treatment using eco-friendly chemical agents. A uniform, tightly bonded early-stage protective rust layer (red-brown to orange-yellow) is formed within hours, eliminating the need for 1–2 years of natural weathering. | Rust layer thickness: 10 – 30 μm (color deepens over time) |
| CS (Coated & Stabilized) | Rust-stabilized surface treated with a transparent protective sealer after natural or artificial rusting. It preserves the aesthetic rust appearance while preventing runoff, staining, or contamination of surrounding surfaces. | Coating thickness: 15 – 25 μm (matte or semi-matte finish) |
| PT (Painted / Coated) | Protective coated surface applied mainly on non-exposed or concealed areas (e.g., bridge interiors or underground parts). After blasting, epoxy zinc-rich primer or heavy-duty coating is applied for additional corrosion protection. | Dry film thickness (DFT): ≥ 150 μm |
Here is the equivalence table for ASTM A588 (High-Strength Low-Alloy Weathering Steel) mapped against major international standards such as European (EN), Chinese (GB), Japanese (JIS), and ISO specifications.
ASTM A588 Weathering Steel Plate Price per kg
FOB (China-origin): Typically US$ 750 to US$ 1,250 per metric ton, equivalent to US$ 0.75 to US$ 1.25 per kilogram (usually subject to a minimum order quantity of 5 to 10 metric tons for standard specifications).
Retail / Small-batch / Deep Processing: Prices for small quantities, specific customized sizes, or processed parts (such as shot-blasting, pre-rusted, or laser-cut parts) generally range from US$ 1.45 to US$ 2.60 per kilogram, depending on exact plate thickness, dimensional tolerances, and surface treatment requirements.
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International Equivalent Grades for ASTM A588
| Standard | Equivalent Grade |
| ASTM (USA) | A588 Grade A / B / C / K |
| EN 10025-5 (Europe) | S355J0W / S355J2W / S355K2W |
| GB/T 4171 (China) | Q355GNH / Q355GNHL |
| JIS G3114 (Japan) | SMA490AW / SMA490BW / SMA490CW |
Application Case of A588 Weathering Steel Plate
A customer from Melbourne, Australia, required weathering steel bridge for an urban project and selected 120 tons of ASTM A588 weathering steel plates for fabrication.
To meet the project's aesthetic and durability requirements, the steel plates underwent Sa2.5 shot blasting, accelerated pre-rusting treatment, and Coated & Stabilized sealing treatment, ensuring a uniform reddish-brown appearance while effectively preventing rust runoff.
For quality assurance, all materials passed yield strength testing (≥345 MPa) and 180° cold bending tests, while critical welds were inspected through Penetrant Testing (PT) to ensure excellent structural integrity and long-term weather resistance.
The weathering steel bridge is successfully delivered and installed, earning high praise from the client for its outstanding visual appeal, durability, and low maintenance requirements.
What is difference between the A588 Grade A and A588 Grade K?
ASTM A588 Grade A and ASTM A588 Grade K are both high-strength low-alloy weathering steels with excellent atmospheric corrosion resistance. Compared with A588 Grade A, A588 Grade K not only offers higher yield strength (485 MPa) and tensile strength (620–760 MPa), but also includes an additional Charpy V-notch (CVN) impact test requirement, which is used to evaluate the material's low-temperature impact toughness.
Therefore, ASTM A588 Grade K is more suitable for cold environments, bridge structures, and heavy-duty engineering applications with higher structural safety requirements.