Q690qF Bridge Steel Plate
High-strength structural steel designed for long-span bridge engineering, compliant with GB/T 714-2015, offering excellent durability and reliability at -60°C low-temperature environment.
About Q690qF Bridge Steel Plate
Q690qF is a high-strength low-alloy structural steel under Chinese standard (GB/T 714-2015), specially developed for large-span bridge engineering in frigid regions.
The letter "q" in the grade stands for "qiaoliang" (bridge), and "F" indicates the steel's impact test temperature is -60°C, suitable for long-span bridge construction projects in frigid regions of China and worldwide.
This steel features ultra-high reliable strength (yield strength 690MPa), excellent weldability, and outstanding ultra-low-temperature toughness, making it the optimal choice for long-span bridge infrastructure projects in -60°C low-temperature environments.
Technical Specifications
Basic Information
Mechanical Properties
| Thickness(mm) | Yield Strength(MPa) ≥ | Tensile Strength(MPa)≥ | Elongation(%) ≥ | Impact Energy(J) ≥ |
|---|---|---|---|---|
| ≤50 | 690 | 770 | 14 | 47 |
| ＞50--≤100 | 650 | 770 | 14 | 47 |
| ＞100--≤150 | - | 770 | 14 | 47 |
Q690qF Chemical composition of tempered steel (Mass Fraction %)
| Element | C ≤ | Si ≤ | Mn | Nb | V | Ti | Als | Cr ≤ | Ni ≤ | Cu ≤ | Mo ≤ | N ≤ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Content | 0.15 | 0.55 | 0.80-1.70 | 0.005-0.090 | 0.010-0.080 | 0.006-0.030 | 0.010-0.045 | 0.40-1.00 | 0.25-1.20 | 0.15-0.55 | 0.20-0.60 | 0.008 |
Note: Carbon Equivalent (Ceq) ≤ 0.48%, Welding Carbon Equivalent (Pcm) ≤ 0.26%. Optimized chemical composition balances ultra-high reliable strength (690MPa yield strength) with -60°C ultra-low-temperature toughness, ideal for frigid region long-span bridge applications.
International Standard Comparison
Mechanical Properties Comparison (Thickness ≤50mm)
| Property | Q690qF (GB/T 714-2015) | S690NL (EN 10025) | A709 Gr70 (ASTM A709) |
|---|---|---|---|
| Min Yield Strength (MPa) | 690 | 690 | 485 (70 ksi) |
| Tensile Strength (MPa) | 770 | 770 | 550-720 (80-104 ksi) |
| Min Elongation (%) | 14 | 16 | 18 |
| Impact Test Temperature (°C) | -60 | -20 | -20°C |
Chemical Composition Comparison (%)
| Element | Q690qF (Max/Range) | S690NL (EN 10025) (Max/Range) | A709 Gr70 (ASTM A709) (Max/Range) |
|---|---|---|---|
| Carbon (C) | ≤0.15 | ≤0.22 | ≤0.23 |
| Silicon (Si) | ≤0.55 | ≤0.60 | 0.15-0.40 |
| Manganese (Mn) | 0.80-1.70 | 1.40-1.90 | 0.90-1.60 |
Key Differences Summary:
- Q690qF offers ultra-high yield strength (690MPa) with excellent -60°C ultra-low-temperature toughness
- Stricter impurity limits ensure superior performance in frigid environments
- Impact test temperature of -60°C, designed for frigid region long-span bridge construction
- Optimized carbon equivalent (Ceq ≤ 0.48%) and welding carbon equivalent (Pcm ≤ 0.26%) maintain excellent weldability
- Ultra-high-strength solution for long-span bridges in frigid climate regions
- Strict quality control meets GB/T 714-2015 standard requirements for bridge steel
Application Projects
Frigid Region Long-Span Highway Bridge
Used for long-span highway bridges in frigid regions, providing excellent ultra-low-temperature toughness and structural stability at -60°C environment.
- Plate Thickness: 25mm-70mm
- Total Consumption: 28,500 tons
- Suitable for -60°C ultra-low-temperature environments
Frigid Region Long-Span Railway Bridge Project
Applied to long-span railway bridges in frigid climate areas, featuring outstanding fatigue resistance and stable ultra-low-temperature mechanical properties.
- Total Consumption: 35,600 tons
- 100-year design life in frigid environments
Frigid Region Urban Long-Span Viaduct Project
Used for long-span urban viaduct bridges in northern frigid cities, offering reliable structural support and excellent ultra-low-temperature performance.
- Plate Thickness: 35mm-75mm
- Total Consumption: 29,400 tons
- Excellent weldability in ultra-low temperatures
Other Typical Applications
Frequently Asked Questions (FAQ)
What is the difference between Q690qF and Q690qD/Q690qE steel plates?
Main differences between Q690qF, Q690qD and Q690qE bridge steel plates:
- Impact Test Temperature: Q690qD (-20°C) ＜ Q690qE (-40°C) ＜ Q690qF (-60°C)
- Impurity Limits: Q690qD (general) ＜ Q690qE (stricter) ＜ Q690qF (strictest control)
- Application: Q690qD for normal cold regions, Q690qE for extremely cold regions, Q690qF for frigid regions
- Low-Temperature Performance: Q690qF has excellent toughness at -60°C ultra-low temperature
- Environment Adaptability: Q690qF for frigid climate long-span projects
What are the welding requirements for Q690qF steel plates?
Q690qF has excellent weldability (Ceq ≤0.48%) with special requirements for ultra-low temperature environments:
- Preheat to 220-260°C when ambient temperature <0°C for all thicknesses
- Preheat to 260-300°C for thickness >40mm at normal temperatures
- Use E8018-G/E9015-G low-alloy electrodes for high-strength welding
- Interpass temperature control 260-300°C during multi-pass welding
- Post-weld slow cooling and insulation required in ambient temperature < -20°C conditions
- Optimized for reliable welding joints in frigid environment construction
Follow strict frigid region welding procedures for Q690F series ultra-high-strength structural steels.
What is the operating temperature range of Q690qF steel?
Q690qF is designed for frigid climate environments with the following temperature range:
- Minimum Operating Temperature: -60°C (meets impact energy requirements at this temperature)
- Recommended Continuous Operating Temperature: -60°C ~ 200°C
- Short-term Maximum Operating Temperature: 300°C
- Optimal Welding Temperature: Preheating required below 0°C
- Storage/Transport Temperature: Suitable for frigid winter conditions
Q690qF is the preferred ultra-high-strength bridge steel for frigid region long-span infrastructure projects.
What advantages does Q690qF have for frigid region long-span bridge construction?
Q690qF has outstanding advantages for frigid region long-span bridge construction:
- Ultra-high yield strength (690MPa) for super long-span bridge load-bearing requirements
- Excellent -60°C ultra-low-temperature toughness prevents brittle fracture
- Stricter impurity control for superior frigid environment reliability
- Optimized composition ensures stable performance in frigid climates
- Excellent weldability even in ultra-low-temperature construction conditions
- Perfect for northern China frigid and global frigid climate long-span bridge projects
- Complies with GB/T 714-2015 bridge steel standards
These advantages make Q690qF the first choice for ultra-high-strength long-span bridge engineering in frigid climate regions.
What quality inspections are performed for Q690qF steel plates?
Comprehensive quality inspections are provided for Q690qF steel plates:
- EN 10204 3.1 material test certificate with -60°C impact test results
- GB/T 714-2015 bridge steel compliance certification
- 100% ultrasonic testing for internal quality inspection
- Mechanical property test including yield and tensile strength
- -60°C Charpy V-notch impact toughness test report
- Chemical composition analysis with stricter impurity limits
- Third-party inspection certification available upon request
All Q690qF steel plates undergo strict frigid-region quality inspections to ensure compliance.
Core Advantages of Q690qF
-60°C Ultra-Low-Temperature Toughness
Superior ultra-low-temperature performance, ideal for frigid region long-span bridge engineering.
Excellent Frigid Weldability
Optimized carbon equivalent ensures reliable welding performance even in -60°C ultra-low-temperature conditions.
Ultra-High Strength (690MPa)
690MPa ultra-high yield strength, perfect for super long-span bridge construction in frigid zones.
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