Carbon steel Q355B is widely used in bridge construction due to its high strength, good weldability, and reliable performance under load. For overseas bridge projects, particularly in Europe, North America, and Southeast Asia, understanding the mechanical testing standards and certification requirements is critical to ensure compliance and safety.
✅ Mechanical Properties of Q355B
Q355B is a low-alloy, high-strength structural steel that meets Chinese standard GB/T 1591. It features:
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Yield Strength: ≥ 355 MPa
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Tensile Strength: 470–630 MPa
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Elongation: ≥ 20% (depending on thickness)
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Impact Toughness: Tested at -20°C or lower for some export markets
These mechanical properties make Q355B ideal for load-bearing structures in bridge components such as girders, decks, and support beams.
✅ Required Mechanical Testing for Export
To meet international engineering and construction codes, Q355B must pass a series of mechanical tests, typically including:
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Tensile Test (ASTM A370 / ISO 6892)
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Charpy V-Notch Impact Test (ISO 148 / ASTM E23)
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Yield-to-Tensile Ratio Analysis
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Ultrasonic Testing (UT) and Magnetic Particle Inspection (MPI) for weld zones
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Hardness Test in some projects requiring abrasion resistance
Third-party inspection by certified bodies such as SGS, BV, or TÜV is often required before shipment.
✅ Certification Standards
For international bridge projects, Q355B must often comply with:
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EN 10025-2 (for EU acceptance)
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AWS D1.1 / AISC standards (for U.S. structural use)
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ISO 9001 traceability and EN 10204 3.1 or 3.2 MTCs
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Local Ministry of Transport or Public Works approvals
Proper documentation ensures material origin, batch traceability, and testing compliance.
✅ Applications in Overseas Bridge Projects
Q355B steel is commonly used in:
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Highway and railway bridge decks
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Welded box girders and H-beams
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Suspension bridge towers
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Temporary structures and construction supports
Its adaptability to welding, forming, and corrosion protection systems (e.g., hot-dip galvanizing or painting) makes it a top choice in coastal, urban, and seismic environments.
Conclusion
To meet the demanding requirements of overseas bridge construction, Q355B carbon steel must undergo strict mechanical testing and certification. Its robust properties and international adaptability make it a strong, reliable material choice in modern infrastructure.