Q370qD Bridge Steel Plate
High-strength structural steel designed for bridge engineering, compliant with GB/T 714-2015, offering excellent durability and reliability at -20°C low-temperature environment.
About Q370qD Bridge Steel Plate
Q370qD is a high-strength low-alloy structural steel under Chinese standard (GB/T 714-2015), specially developed for bridge engineering projects in severe low-temperature environments.
The letter "q" in the grade stands for "qiaoliang" (bridge), and "D" indicates the steel's impact test temperature is -20°C, suitable for bridge construction projects in cold and severely cold regions of China and worldwide.
This steel features reliable strength (yield strength 370MPa), excellent weldability, and outstanding low-temperature toughness, making it an ideal choice for bridge infrastructure projects in severe cold climate zones.
Technical Specifications
Basic Information
Mechanical Properties
| Thickness(mm) | Yield Strength(MPa) ≥ | Tensile Strength(MPa)≥ | Elongation(%) ≥ | Impact Energy(J) ≥ |
|---|---|---|---|---|
| ≤50 | 370 | 510 | 20 | 120 |
| ＞50--≤100 | 360 | 510 | 20 | 120 |
| ＞100--≤150 | - | 510 | 20 | 120 |
Chemical Composition (Hot-rolled/Normalized)
| Grade | Quality | C ≤% | Si ≤% | Mn % | Nb % | V % | Ti % | Als % | Cr ≤% | Ni ≤% | Cu ≤% | N ≤% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Q370q | D | 0.18 | 0.55 | 1.00~1.60 | 0.005~0.060 | 0.010~0.080 | 0.006~0.030 | 0.010~0.045 | 0.3 | 0.3 | 0.3 | 0.008 |
a: Al, Nb, V, Ti can be added alone or in combination. Nb+V+Ti ≤ 0.22%.
b: Total aluminum (Alt): 0.015%~0.050%.
Chemical Composition (TMCP)
| Grade | Quality | C ≤% | Si ≤% | Mn % | Nb % | V % | Ti % | Als % | Cr ≤% | Ni ≤% | Cu ≤% | Mo ≤% | N ≤% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Q370q | D | 0.14 | 0.55 | 1.00~1.60 | 0.010~0.090 | 0.010~0.080 | 0.006~0.030 | 0.010~0.045 | 0.3 | 0.3 | 0.3 | - | 0.008 |
a: Max Mn can be 2.00% by agreement.
b: Al, Nb, V, Ti can be added alone or in combination. Nb+V+Ti ≤ 0.22%.
c: Total aluminum (Alt): 0.015%~0.050%.
International Standard Comparison
Mechanical Properties Comparison (Thickness ≤50mm)
| Property | Q370qD | S355NL | A709 Gr36 |
|---|---|---|---|
| Min Yield Strength (MPa) | 370 | 355 | 250 |
| Tensile Strength (MPa) | 510 | 470-630 | 400-550 |
| Min Elongation (%) | 20 | 22 | 20 |
| Impact Test Temperature (°C) | -20 | -20 | 0 |
Chemical Composition Comparison (%)
| Element | Q370qD | S355NL | A709 Gr36 |
|---|---|---|---|
| Carbon (C) | ≤0.18 | ≤0.22 | ≤0.21 |
| Silicon (Si) | ≤0.55 | ≤0.60 | 0.15-0.40 |
| Manganese (Mn) | 1.00-1.60 | 1.40-1.90 | 0.90-1.60 |
Key Differences Summary:
- Q370qD offers reliable yield strength (370MPa) with excellent -20°C low-temperature toughness
- Designed for bridge projects in severe cold climate regions
- Excellent weldability with Ceq ≤ 0.42%
- Compliant with GB/T 714-2015 standard
Application Projects
Severe Cold Region Highway Bridge
Ideal for medium and small-span highway bridges in severe cold regions, providing excellent ultra-low-temperature stability.
- Plate Thickness: 12mm-50mm
- Total Consumption: 8,600 tons
Severe Cold Area Railway Bridge
Applied to medium-span railway bridges in severe cold zones, featuring outstanding -20℃ low-temperature fatigue resistance.
- Total Consumption: 12,300 tons
- 50-100 years service life
Northern Severe Cold Urban Viaduct
Used for urban viaducts in northern severe cold regions, offering reliable -20℃ structural support.
- Plate Thickness: 16mm-60mm
- Excellent ultra-low-temperature toughness
Frequently Asked Questions (FAQ)
What is the difference between Q370qD and Q370qC/Q370qE steel plates?
Main differences between Q370qD, Q370qC and Q370qE bridge steel plates:
- Impact Test Temperature: Q370qC (0°C) < Q370qD (-20°C) < Q370qE (-40°C)
- Low-Temperature Performance: Q370qE > Q370qD > Q370qC (higher toughness at lower temperature)
- Application: Q370qC for normal temperature areas, Q370qD for cold areas, Q370qE for extremely cold areas
- Price & Cost: Q370qE has the highest performance and cost, for extreme cold environment projects
- Impurity Limits: Strict impurity control to ensure -20℃ low temperature performance
What are the welding requirements for Q370qD steel plates?
Q370qD has excellent weldability (Ceq ≤0.42%) with severe cold-region construction requirements:
- Preheating not required for thickness ≤30mm at ambient temperature ≥-20℃
- Preheat to 80-120℃ for thickness >30mm or ambient temperature <-20℃
- Use E50 series low-alloy electrodes (E5015/E5016) for conventional welding
- Interpass temperature control ≤250℃ during multi-pass welding
- Post-weld heat treatment not required for general bridge components
- Professional welding process recommended for -20℃ low temperature environments
Follow standard welding procedures for Q370 series high-strength structural steels in severe cold regions.
What is the operating temperature range of Q370qD steel?
Q370qD is designed for severe low temperature environments with the following temperature range:
- Minimum Operating Temperature: -20°C (meets impact energy requirements at this temperature)
- Recommended Continuous Operating Temperature: -20°C ~ 200°C
- Short-term Maximum Operating Temperature: 300°C
- Application Environment: Suitable for severe cold regions in northern China and worldwide
- Storage/Transport Temperature: Adaptable to ultra-low temperature environments
Q370qD is a high-strength bridge steel for severe cold climate bridge projects.
What advantages does Q370qD have for cold region bridge construction?
Q370qD has outstanding advantages for severe cold region bridge construction:
- Excellent low-temperature toughness: Stable performance at -20°C, preventing brittle fracture
- Reliable strength: 370MPa yield strength meets severe cold region bridge load-bearing requirements
- Good weldability in ultra-low temperatures: Suitable for on-site construction in severe cold climates
- Wide application: Ideal for highway, railway, urban bridges in northern severe cold regions
- High performance: Higher grade than Q370qC bridge steel
- National standard certification: Fully compliant with GB/T 714-2015 bridge steel standards
- Stable quality: Mature production process for ultra-low-temperature bridge steel
These advantages make Q370qD an ideal choice for bridge engineering in severe cold climate zones.
What quality inspections are performed for Q370qD steel plates?
Comprehensive quality inspections are provided for Q370qD steel plates:
- EN 10204 3.1 material test certificate with -20°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
- -20°C Charpy V-notch impact toughness test report
- Chemical composition analysis in accordance with national standard
- Third-party inspection certification available upon request
All Q370qD steel plates undergo strict quality inspections to ensure severe cold region engineering compliance.
Core Advantages
-20℃ Low-Temperature Toughness
Outstanding performance in severe cold climate environments.
Excellent Weldability
Optimized carbon equivalent ensures easy welding.
Severe Cold Adaptability
Perfect for bridge projects in northern severe cold areas.
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