Q345qE Bridge Steel Plate
High-strength structural steel designed for bridge engineering, compliant with GB/T 714-2015, offering excellent durability and reliability at -40°C low-temperature environment.
About Q345qE Bridge Steel Plate
Q345qE is a high-strength low-alloy structural steel under Chinese standard (GB/T 714-2015), specially developed for bridge engineering projects in extremely low-temperature environments.
The letter "q" in the grade stands for "qiaoliang" (bridge), and "E" indicates the steel's impact test temperature is -40°C, suitable for bridge construction projects in extremely cold regions of China and worldwide.
This steel features reliable strength (yield strength 345MPa), excellent weldability, and outstanding ultra-low-temperature toughness, making it an ideal choice for bridge infrastructure projects in extremely cold climate zones.
Technical Specifications
Basic Information
Mechanical Properties
| Thickness(mm) | Yield Strength(MPa) ≥ | Tensile Strength(MPa)≥ | Elongation(%) ≥ | Impact Energy(J) ≥ |
|---|---|---|---|---|
| ≤50 | 345 | 490 | 20 | 120 |
| ＞50--≤100 | 335 | 490 | 20 | 120 |
| ＞100--≤150 | 305 | 490 | 20 | 120 |
Chemical Composition (Hot-rolled/Normalized)
| Grade | Quality | C ≤% | Si ≤% | Mn % | Nb % | V % | Ti % | Als % | Cr ≤% | Ni ≤% | Cu ≤% | N ≤% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Q345q | E | 0.18 | 0.55 | 0.90~1.60 | 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 ≤% |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Q345q | E | 0.14 | 0.55 | 0.90~1.60 | 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 | Q345qE | S355NL | A709 Gr36 |
|---|---|---|---|
| Min Yield Strength (MPa) | 345 | 355 | 250 |
| Tensile Strength (MPa) | 490 | 470-630 | 400-550 |
| Min Elongation (%) | 20 | 22 | 20 |
| Impact Test Temperature (°C) | -40 | -20 | 0 |
Chemical Composition Comparison (%)
| Element | Q345qE | S355NL | A709 Gr36 |
|---|---|---|---|
| Carbon (C) | ≤0.18 | ≤0.22 | ≤0.21 |
| Silicon (Si) | ≤0.55 | ≤0.60 | 0.15-0.40 |
| Manganese (Mn) | 0.90-1.60 | 1.40-1.90 | 0.90-1.60 |
Key Differences Summary:
- Q345qE offers reliable yield strength (345MPa) with excellent -40°C ultra-low-temperature toughness
- Designed for bridge projects in extremely cold climate regions
- Excellent weldability with Ceq ≤ 0.42%
- Compliant with GB/T 714-2015 standard
Application Projects
Extremely Cold Region Highway Bridge
Ideal for medium and small-span highway bridges in extremely cold regions, providing excellent ultra-low-temperature stability.
- Plate Thickness: 12mm-50mm
- Total Consumption: 8,600 tons
Extremely Cold Area Railway Bridge
Applied to medium-span railway bridges in extremely cold zones, featuring outstanding ultra-low-temperature fatigue resistance.
- Total Consumption: 12,300 tons
- 50-100 years service life
Northern Extreme Cold Urban Viaduct
Used for urban viaducts in northern extremely cold regions, offering reliable ultra-low-temperature structural support.
- Plate Thickness: 16mm-60mm
- Excellent ultra-low-temperature toughness
Frequently Asked Questions (FAQ)
What is the difference between Q345qE and Q345qC/Q345qD steel plates?
Main differences between Q345qC, Q345qD and Q345qE bridge steel plates:
- Impact Test Temperature: Q345qC (0°C) < Q345qD (-20°C) < Q345qE (-40°C)
- Low-Temperature Performance: Q345qE > Q345qD > Q345qC (higher toughness at lower temperature)
- Application: Q345qC for normal temperature areas, Q345qD for cold areas, Q345qE for extremely cold areas
- Price & Cost: Q345qE has the highest performance and cost, for extreme cold environment projects
- Impurity Limits: The strictest impurity control among the three grades
What are the welding requirements for Q345qE steel plates?
Q345qE has excellent weldability (Ceq ≤0.42%) with ultra-cold-region construction requirements:
- Preheating not required for thickness ≤30mm at ambient temperature ≥-40℃
- Preheat to 100-150℃ for thickness >30mm or ambient temperature <-40℃
- 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 ultra-low temperature environments
Follow standard welding procedures for Q345 series high-strength structural steels in extremely cold regions.
What is the operating temperature range of Q345qE steel?
Q345qE is designed for extremely low temperature environments with the following temperature range:
- Minimum Operating Temperature: -40°C (meets impact energy requirements at this temperature)
- Recommended Continuous Operating Temperature: -40°C ~ 200°C
- Short-term Maximum Operating Temperature: 300°C
- Application Environment: Suitable for extremely cold regions in northern China and worldwide
- Storage/Transport Temperature: Adaptable to ultra-low temperature environments
Q345qE is the top choice high-strength bridge steel for extremely cold climate bridge projects.
What advantages does Q345qE have for extremely cold region bridge construction?
Q345qE has outstanding advantages for extremely cold region bridge construction:
- Excellent ultra-low-temperature toughness: Stable performance at -40°C, preventing brittle fracture
- Reliable strength: 345MPa yield strength meets extremely cold region bridge load-bearing requirements
- Good weldability in ultra-low temperatures: Suitable for on-site construction in extreme cold climates
- Wide application: Ideal for highway, railway, urban bridges in northern extremely cold regions
- Top performance: The highest grade of Q345q series 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 Q345qE the first choice for bridge engineering in extremely cold climate zones.
What quality inspections are performed for Q345qE steel plates?
Comprehensive quality inspections are provided for Q345qE steel plates:
- EN 10204 3.1 material test certificate with -40°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
- -40°C Charpy V-notch impact toughness test report
- Chemical composition analysis in accordance with national standard
- Third-party inspection certification available upon request
All Q345qE steel plates undergo strict quality inspections to ensure extremely cold region engineering compliance.
Core Advantages
-40℃ Ultra-Low-Temperature Toughness
Outstanding performance in extremely cold climate environments.
Excellent Weldability
Optimized carbon equivalent ensures easy welding.
Extreme Cold Region Adaptability
Perfect for bridge projects in northern extremely cold areas.
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