Q310GNH Atmospheric Corrosion Resistant Weathering Steel Plate
🛡️ Patina-Forming Steel with 310 MPa Minimum Yield Strength & Enhanced Durability
What is Q310GNH Weathering Steel?
Q310GNH is a Chinese-grade structural weathering steel standardized under GB/T 4171. The "GNH" stands for "Gao Nai Hou" (高耐候), directly translating to "high weather resistance". With a minimum yield strength of 310 MPa, Q310GNH is a high-performance weathering steel that offers an excellent balance of strength, formability, and corrosion resistance. It forms a dense, stable, and adherent rust layer (the patina) under cyclic wet/dry conditions, providing 2 to 8 times the atmospheric corrosion resistance of standard carbon steel. This grade is widely used in structural applications requiring higher strength combined with enhanced atmospheric corrosion resistance.
Decoding the Grade: Q310GNH
The naming follows the Chinese steel grade system, where each part reveals key performance characteristics:
Core Value Proposition
Q310GNH delivers exceptional lifecycle cost savings by merging structural strength with built-in corrosion protection. It is engineered for projects requiring good load-bearing capacity without sacrificing longevity, providing a robust, low-maintenance material solution.
Your Partner for Weathering Steel Supply
We are a professional Chinese supplier offering Q310GNH weathering steel plates, sheets, and sections for global projects. We provide mill-direct ordering with full traceability and support the entire export process, ensuring you receive material that meets both GB/T 4171 and your specific project requirements.
Start Your Q310GNH Project
We offer flexible procurement options for Q310GNH, from technical consultation to reliable delivery. Benefit from competitive pricing, strict quality adherence to GB/T 4171, and dedicated support for your international project needs.
✓ Formal quotation within 8-12 hours
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✓ Export documentation support
Standards & International Comparisons
Q310GNH is specified under the Chinese National Standard GB/T 4171 "Weathering Structural Steels". While direct, chemically identical equivalents in other standards are rare due to differing numbering systems, Q310GNH is functionally comparable to several internationally recognized weathering steel grades, offering similar performance characteristics for atmospheric corrosion resistance.
Comparison with Key International Standards
| Standard | Comparable Grade | Key Similarity | Note |
|---|---|---|---|
| GB/T 4171 (China) | Q310GNH | Primary reference grade. | Defines chemical composition & mechanical properties. |
| DIN EN 10025-5 (Europe) | S275J0W / S275J2W | Similar yield strength (275-355 MPa) and weathering principle. | J0/J2 indicates impact toughness temperature. Widely used European weathering steel. |
| ASTM A588 (USA) | Grade A (~345 MPa) | Comparable weathering performance for structural use. | A588 has slightly higher min yield. Common US weathering steel spec. |
| JIS G3125 (Japan) | SMA400W | Similar weathering and strength level (min 400 MPa tensile). | Japanese high-performance weathering steel for welded structures. |
Important Note: The table indicates functional comparability, not chemical identity. Q310GNH features specific alloying for enhanced weathering performance. For any project requiring material substitution or governed by specific regional codes, engineers must verify suitability.
Chemical Composition (GB/T 4171)
The specific alloying elements (notably Copper, Chromium, Nickel, and Phosphorus) are key to forming the protective patina. The following table details the mandatory and optional composition requirements for Q310GNH.
| Grade | Chemical Composition (Quality Fraction)/% | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| C | Si | Mn | P | S | Cu | Cr | Ni | others | ||
| Q310GNH | ≤0.12 | 0.25 ~ 0.75 | 0.20 ~ 0.50 | 0.07 ~ 0.12 | ≤0.020 | 0.20 ~ 0.45 | 0.30 ~ 1.25 | ≤0.65 | a , b | |
| Notes: ᵃ To improve the properties of steel, one or more trace alloying elements may be added: Nb 0.015%~0.060%, V 0.02%~0.12%, Ti 0.02%~0.10%, Alt ≥0.020%. When the above elements are used in combination, at least one element should be ensured to meet the lower limit of the above chemical composition. ᵇ The following alloying elements can be added: Mo≤0.30%, Zr≤0.15%. ᶜ The total amount of the three alloying elements Nb, V, and Ti added should not exceed 0.22%. ᵈ Through negotiation between the supplier and the buyer, the sulfur content may not exceed 0.008%. ᵉ Through negotiation between the supply and demand parties, a lower limit for Ni content may not be required. ᶠ Through negotiation between the supply and demand parties, the content of C may not exceed 0.15%. |
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Production & Delivery (Based on GB/T 4171)
Smelting Methods: The steel is smelted in a converter or electric furnace and is killed steel. Unless otherwise specified, the smelting method shall be selected by the supplier.
Delivery Status: Hot-rolled steel is delivered in hot-rolled, controlled-rolled, or normalized condition. Steel grades Q460NH, Q500NH, and Q550NH can be delivered in quenched and tempered condition. Cold-rolled steel is generally delivered in annealed condition.
Permissible Deviations: Shall comply with GB/T 222.
Mechanical & Processing Properties
Q310GNH provides structural strength (310 MPa min yield) combined with good formability and weldability. The mechanical properties vary slightly with plate thickness as detailed below.
| Grade | Tensile Test a | 180° Bending test mandrel diameter | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lower yield strength ReL ≥ (MPa) | Tensile Strength Rm (MPa) |
Elongation after fracture A/% ≥ | ||||||||||||
| ≤16 | >16~40 | >40~60 | >60 | ≤16 | >16~40 | >40~60 | >60 | ≤6 | >6~16 | >16 | ||||
| Q310GNH | 310 | - | - | - | ≥450 | 26 | - | - | - | a | - | - | ||
Note: 'a' represents the steel thickness (in mm). When a yield plateau is not evident, Rp0.2 may be used.
Advantages & Typical Applications
Key Advantages
- Guaranteed Strength (310 MPa): Reliable load-bearing capacity for structural designs.
- Superior Corrosion Resistance: 2-8x better than carbon steel, reducing maintenance.
- Low Lifecycle Cost: Eliminates or reduces painting requirements.
- Aesthetic Patina: Develops a stable, attractive russet-brown appearance.
- Good Weldability & Fabrication: Suitable for standard welding and forming processes.
- Sustainable Choice: Extended service life and reduced coating use.
Typical Applications
- Structural components (bridges, building frames).
- Highway guardrails, sound barriers.
- Transmission towers, telecommunication masts.
- Railway rolling stock, containers, and frames.
- General structural fabrication requiring higher strength.
- Outdoor sculptures and architectural cladding.
Frequently Asked Questions (FAQ)
Find quick answers to the most common questions about Q310GNH weathering steel. For more detailed inquiries, please don't hesitate to contact us.
Q310GNH has a minimum yield strength of 310 MPa for thicknesses up to 16mm. This strength level makes it suitable for a wide range of structural applications requiring higher load-bearing capacity combined with atmospheric corrosion resistance.
Like all weathering steels, Q310GNH is designed to form a protective patina, so painting is generally not required for corrosion protection in most atmospheric environments. This leads to significant long-term maintenance savings. Painting is only necessary for aesthetic reasons or in exceptionally aggressive environments.
Functionally comparable grades include S275J0W/J2W (EN 10025-5) and SMA400W (JIS G3125). They are designed as weathering steels. However, Q310GNH features specific alloying, particularly phosphorus, for enhanced weathering performance. Always verify specific properties before substitution.
Yes, Q310GNH has good weldability. Standard welding processes (SMAW, GMAW, FCAW) can be used. It is recommended to use low-hydrogen consumables that match the strength and corrosion resistance of the base metal. Due to the phosphorus content, proper welding procedures should be followed to avoid hot cracking.
For standard sizes, MOQ starts from 5 tons. Stock items can ship in 7-14 days. Custom mill production typically requires 20-35 days. Please contact us with your specific requirements for an accurate lead time and quotation.
Supply Information
Available Forms
- Plates & Sheets
- Hot-rolled Coils
- Sections (H-beams, I-beams, Channels, Angles)
- Bars
Delivery Condition
- Hot-rolled: As-rolled, controlled-rolled, or normalized.
- Cold-rolled: Generally delivered in annealed condition.
ℹ️ All technical data is based on GB/T 4171 and is for reference. Contact our sales team for a detailed technical consultation.
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