GB/T 4171 Q355GNH Corten steel plate is a premium weathering steel known for its excellent atmospheric corrosion resistance. It belongs to the low-alloy steel family and is widely used in structural applications where long-term exposure to the environment is required.
Compared to stainless steel, Q355GNH contains only trace amounts of alloying elements, including copper (Cu), nickel (Ni), phosphorus (P), chromium (Cr), molybdenum (Mo), niobium (Nb), vanadium (V), titanium (Ti), and others.
These elements form a stable protective oxide layer, giving the steel its characteristic rust-colored patina while effectively preventing further corrosion.
Key Advantages of GB/T 4171 Q355GNH Corten Steel Plate
Outstanding corrosion resistance: The steel naturally forms a dense protective layer when exposed to atmospheric conditions, reducing the need for maintenance and repainting.
Excellent weldability: Suitable for complex structures and construction projects requiring high-strength welded joints.
Versatility in applications: Used in shipping containers, outdoor building support frames, and industrial structural components, especially in environments with caustic gases or liquids.
High mechanical performance: Offers a strong combination of yield strength, tensile strength, and elongation, making it suitable for heavy-duty applications.
Products Specifications
Thickness: 2–300 mm
Width: 1000–4200 mm
Length: 1000–12,000 mm
Surface Treatment: Normalizing, drawing-back, annealing, painted
Heat Treatment: Quenched, normalized, tempering, Q+T
Packing: Export-sea worthy packing, each bundle tied and protected
Terms: FOB, CFR, CIF, etc.
Chemical Composition (%)
| Element | Content |
|---|---|
| C | ≤ 0.12 |
| Si | 0.20–0.75 |
| Mn | ≤ 1.00 |
| P | ≤ 0.13 |
| S | ≤ 0.13 |
| Cu | 0.25–0.55 |
| Cr | 0.40–0.80 |
| Ni | ≤ 0.65 |
Mechanical Properties
| Property | Value |
|---|---|
| Yield Strength (MPa) | 345–355 |
| Tensile Strength (MPa) | 490–630 |
| Elongation (%) | ≥ 22 |
| Technique | Hot Rolled |
GB/T 4171 Q355GNH Corten steel plate is a first-class material offered by Bebon International, combining high quality, competitive pricing, and professional service. This steel plate is ideal for applications requiring both strength and durability in harsh atmospheric or chemical environments.
If Q355GNH Corten steel plate meets your project requirements, please feel free to contact us. We look forward to cooperating with you and providing excellent solutions for your construction and industrial needs.
1. What is Q355NHB steel?
Q355NHB is a Chinese standard weathering steel grade under GB/T 4171. The "Q" stands for yield strength, "355" means a minimum yield strength of 355 MPa, "NH" indicates weathering (atmospheric corrosion-resistant) steel, and "B" is the quality grade. It is designed to form a dense and stable rust layer on its surface when exposed to the atmosphere, which protects the steel from further corrosion and significantly extends its service life.
2. What is the difference between Q355NHB and ordinary carbon steel?
Unlike ordinary carbon steel, Q355NHB contains alloying elements such as copper, chromium, nickel, and phosphorus, which allow it to form a protective oxide layer after exposure to rain and air. This natural patina prevents moisture and oxygen from penetrating into the steel, while carbon steel continues to rust until it deteriorates. As a result, Q355NHB has much better corrosion resistance and requires far less maintenance over time.
3. What are the main applications of Q355NHB steel?
Q355NHB is widely used in bridges, railway vehicles, container structures, outdoor buildings, power transmission towers, and architectural façades where long-term atmospheric exposure is expected. It is also popular in modern architectural and landscape designs because its natural rust color provides an attractive industrial and aesthetic appearance without the need for painting.
4. Is Q355NHB equivalent to ASTM A588 weathering steel?
Q355NHB is often considered the Chinese equivalent of ASTM A588 because both are weathering steels with similar corrosion-resistant mechanisms and mechanical strength levels. However, they follow different national standards and have slightly different chemical composition ranges. In practical engineering, Q355NHB can usually be used as a substitute for A588 in many structural and architectural applications after technical confirmation.
5. Does Q355NHB require painting or coating?
In most outdoor applications, Q355NHB does not require painting because it naturally forms a stable rust layer that protects the steel. This eliminates the need for periodic repainting, significantly reducing maintenance costs. However, in environments with high chloride content, such as marine or coastal areas, additional protective coatings may be recommended to ensure long-term durability.
6. What are the mechanical properties of Q355NHB?
Q355NHB has a minimum yield strength of 355 MPa and a tensile strength typically between 470 and 630 MPa, depending on plate thickness. It also offers good elongation and impact toughness, allowing it to withstand dynamic loads, vibration, and temperature variations. These properties make it suitable for both structural and load-bearing applications.
7. Is Q355NHB easy to weld and process?
Yes, Q355NHB has good weldability, cutting performance, and forming ability, similar to conventional low-alloy structural steels. Standard welding methods such as MIG, TIG, and submerged arc welding can be used, though low-hydrogen electrodes are recommended to avoid cracking. Preheating may be required for thicker plates to ensure weld quality.
8. How does Q355NHB save maintenance costs?
Because Q355NHB forms a self-protecting rust layer, it does not need regular repainting or anti-corrosion treatment like carbon steel. Over the life of a structure, this can reduce maintenance costs by more than 50%, especially for bridges, outdoor steel frames, and large exposed structures, making it a very cost-effective solution.
