Q460qD Bridge Steel Plate
Ultra-high-strength structural steel specifically designed for heavy-load and super-long-span bridge construction in cold environments, meeting GB/T 714-2015 standards for durability and reliability in low temperature conditions down to -20°C.
About Q460qD Steel
Q460qD is a Chinese standard (GB/T 714-2015) ultra-high-strength low alloy structural steel specifically developed for heavy-load and super-long-span bridge construction in cold climate zones.
The "q" in the designation stands for bridge (qiaoliang in Chinese), while "D" indicates the steel's impact test temperature of -20°C, making it suitable for cold climate conditions in northern China, high-altitude regions and severe weather applications.
It offers exceptional ultra-high strength (460MPa yield strength), excellent weldability, and superior low-temperature toughness, making it the premium choice for super-long-span, heavy-load and high-rise bridge infrastructure in cold environments down to -20°C.
Technical Specifications
Basic Information
Mechanical Properties
| Thickness (mm) | Yield Strength (MPa) ≥ | Tensile Strength (MPa) | Elongation (%) ≥ | Impact Energy (J) ≥ |
|---|---|---|---|---|
| ≤16 | 460 | 550-720 | 18 | 34 |
| >16-35 | 440 | 550-720 | 18 | 34 |
| >35-50 | 430 | 550-720 | 18 | 34 |
| >50-100 | 420 | 530-700 | 18 | 30 |
Chemical Composition (wt%)
| Element | C ≤ | Si ≤ | Mn | P ≤ | S ≤ | Nb ≤ | V ≤ | Ti ≤ | Ni ≤ | Cu ≤ |
|---|---|---|---|---|---|---|---|---|---|---|
| Content | 0.18 | 0.55 | 1.00-1.80 | 0.020 | 0.015 | 0.06 | 0.10 | 0.02 | 0.80 | 0.50 |
Note: Carbon equivalent (Ceq) ≤ 0.45%, Weldability carbon equivalent (Pcm) ≤ 0.24%. The optimized chemical composition balances ultra-high strength (460MPa yield) with excellent low-temperature toughness at -20°C for heavy-load bridge applications in cold environments. Nickel content (0.80%) enhances low temperature performance while maintaining excellent weldability.
International Standards Comparison
Mechanical Properties Comparison (≤16mm thickness)
| Property | Q460qD (GB/T 714-2015) | S460NL (EN 10025) | A709 Gr65 (ASTM A709) |
|---|---|---|---|
| Yield Strength (MPa) min | 460 | 460 | 450 (65 ksi) |
| Tensile Strength (MPa) | 550-720 | 550-680 | 550-700 (80-100 ksi) |
| Elongation (%) min | 18 | 19 | 20 |
| Impact Test Temperature (°C) | -20 | -50 | -18 (0°F) |
| Impact Energy (J) min | 34 | 40 | 34 (25 ft-lb) |
| Carbon Equivalent (Ceq) max | 0.45% | 0.48% | 0.45% |
Chemical Composition Comparison (wt%)
| Element | Q460qD (max/ range) | S460NL (EN 10025) (max/ range) | A709 Gr65 (ASTM A709) (max/ range) |
|---|---|---|---|
| Carbon (C) | ≤0.18% | ≤0.20% | ≤0.20% |
| Silicon (Si) | ≤0.55% | ≤0.60% | 0.15-0.50% |
| Manganese (Mn) | 1.00-1.80% | 1.00-1.70% | 1.30-1.70% |
| Phosphorus (P) | ≤0.020% | ≤0.025% | ≤0.030% |
| Sulfur (S) | ≤0.015% | ≤0.020% | ≤0.030% |
| Niobium (Nb) | ≤0.06% | ≤0.06% | ≤0.05% |
| Vanadium (V) | ≤0.10% | ≤0.12% | ≤0.10% |
| Titanium (Ti) | ≤0.02% | ≤0.05% | ≤0.03% |
Key Differences Summary:
- Q460qD offers ultra-high yield strength (460MPa) with low temperature toughness (-20°C), ideal for super-long-span and heavy-load bridge applications in cold environments
- Optimized carbon content (≤0.18%) and strict P/S control (0.020/0.015%) ensure excellent low temperature toughness at -20°C
- Nickel allowance (0.80%) enhances low temperature performance for cold regions without compromising weldability
- Impact test temperature of -20°C makes it suitable for cold regions in northern China and high-altitude areas
- Controlled carbon equivalent (0.45%) maintains excellent weldability while achieving ultra-high strength for cold applications
- Balanced manganese content (1.00-1.80%) optimizes strength-toughness balance for heavy-load applications in cold conditions
Application Cases
Yangtze River Super-long-span Bridge
Used in the main girders of a 1.2km span cable-stayed bridge over the Yangtze River, supporting ultra-heavy traffic loads in cold winter conditions down to -20°C.
- Plate thickness: 40mm-80mm
- Total usage: 58,600 metric tons
- Service life: Designed for 100 years in cold climate
Beijing-Zhangjiakou High-Speed Railway Bridge
Applied in a high-speed railway bridge project for the Beijing-Zhangjiakou line, providing exceptional fatigue resistance and low temperature performance at -20°C.
- Plate thickness: 30mm-70mm
- Total usage: 45,200 metric tons
- Operates at speeds up to 350km/h, -20°C
Sichuan-Tibet Expressway Bridge
Utilized in a heavy-duty expressway bridge in western Sichuan province, designed to withstand heavy truck loads and cold climate conditions down to -18°C.
- Plate thickness: 35mm-85mm
- Total usage: 41,800 metric tons
- Special anti-corrosion coating for cold mountain environments
Other Typical Applications
Frequently Asked Questions (FAQ)
What is the difference between Q460qD and Q460qE steel?
The main differences between Q460qD and Q460qE bridge steel plates are:
- Impact test temperature: Q460qD (-20°C) vs Q460qE (-40°C)
- Carbon content: Q460qD (≤0.18%) vs Q460qE (≤0.16%)
- Phosphorus/Sulfur limits: Q460qD (0.020/0.015%) vs Q460qE (0.015/0.010%)
- Nickel allowance: Q460qD (0.80%) vs Q460qE (1.00%)
- Carbon equivalent: Q460qD (0.45%) vs Q460qE (0.42%)
- Applications: Q460qD for cold (-20°C), Q460qE for extreme cold (-40°C)
What welding precautions are needed for Q460qD in cold weather?
Q460qD has excellent weldability (Ceq ≤ 0.45%), but special precautions apply for welding in cold weather:
- Preheat base metal to ≥15°C when ambient temperature < 0°C (higher than standard grades)
- Preheat to 100-150°C for plates >40mm thick or when temperature < -10°C
- Use low hydrogen welding electrodes (E6015-G/E6016-G) with low temperature toughness
- Maintain interpass temperature ≥100°C during multi-pass welding in cold conditions
- Post-weld heat treatment recommended for thickness >50mm or critical components
- Welding should be performed in sheltered areas when ambient temperature < -15°C
Follow WPS specifically qualified for ultra-high-strength steels in cold environments with impact testing at -20°C.
What is the service temperature range for Q460qD steel?
Q460qD is engineered for cold environments with the following temperature range:
- Minimum operating temperature: -20°C (meets impact energy requirements at this temperature)
- Recommended continuous service: -20°C to 200°C
- Maximum short-term service temperature: 300°C
- Optimal welding temperature: ≥15°C (higher preheating required below this)
- Storage/transport temperature: No lower limit with proper insulation and handling
Q460qD is the standard cold temperature grade in the Q460q series, suitable for cold climate heavy-load applications in northern China and high-altitude regions.
What special treatments enhance Q460qD performance in cold regions?
Several specialized treatments optimize Q460qD for cold environment heavy-load applications:
- TMCP (Thermo-Mechanical Control Process) with accelerated cooling and tempering for ultra-fine grain structure
- Strict impurity control (P≤0.020%, S≤0.015%) to prevent brittle fracture at -20°C
- Normalized heat treatment with precise temperature control for uniform microstructure
- Niobium microalloying (up to 0.06%) for strength enhancement and grain refinement
- Stress relief annealing after welding for all heavy-load components in cold conditions
- Special anti-corrosion coatings with low-temperature flexibility for -20°C environments
- Shot peening for critical components to improve fatigue resistance in cold conditions
These treatments ensure reliable heavy-load performance in cold climate conditions down to -20°C.
What quality certifications are provided for Q460qD steel plates?
We provide comprehensive certification for Q460qD steel plates, including:
- Mill Test Certificate (MTC) EN 10204 3.1 / 3.2 with -20°C impact test results
- GB/T 714-2015 standard compliance certificate for low temperature grades
- Low-temperature toughness test reports (-20°C Charpy V-notch)
- Third-party inspection (SGS, BV, TUV) for cold region projects
- Welding procedure qualification for ultra-high-strength steels in cold environments
- ISO 9001 and CE certification (when required for export to cold climate countries)
- Special certification for high-altitude/cold region applications (when required)
All Q460qD plates undergo 100% ultrasonic testing and additional -20°C impact testing to ensure internal quality for cold-region heavy-load applications.
Key Advantages of Q460qD
Superior Ultra-High-Strength Performance
460MPa yield strength provides exceptional load-bearing capacity for super-long-span and heavy-load bridge applications in cold regions.
Excellent Low Temperature Toughness
Maintains superior toughness at -20°C, ideal for cold climate regions in northern China and high-altitude areas.
Enhanced Weldability
Optimized carbon equivalent (0.45%) ensures excellent welding performance while maintaining ultra-high strength in cold construction conditions.
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