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Q370q Series | Structural Steel for Bridge

Q370q Series | Structural Steel for Bridge

SteelPRO Group provides Q370q series structural steel plates for bridges in stock.

Standards: ISO, ASTM/ASME/AISI, EN, GB/T, DIN, JIS, BS, etc.
Grades: Q370qD/E,  Q345qDNH/ENH
Material: High-Strength Low-Alloy Steel (HSLA)
Thickness: 6-100 mm, or customized
Width: 900-4800 mm, or customized
Length: 3000-25000 mm, or customized
Shape: Plate, Profile (I-beam, H-beam, Angle, Channel, Square bar, Flat bar), Pipe, Coil, Bar, or as request
Condition of Delivery: N/HR/A/T/Q+T/TMCP, or as request
Stock: In stock
Origin: Hebei/Henan/Jiangsu, China
Port: Qingdao

Description

What Is Q370q?

Q370q series steel is high-strength low-alloy structural steel designed for bridge construction. It primarily consists of carbon, manganese, silicon, and other micro-alloying elements to enhance performance.

Naming Rules:

  • Q: Yield strength.
  • 370: Minimum yield strength of 370 MPa.
  • q: Suitable for bridge structure.
  • C/D/E/F: Quality grades. Toughness at 0℃/-20℃/-40℃/-60℃. (e.g. Q370qD)
  • NH: Weather-resistant, designed to withstand atmospheric corrosion. (e.g. Q370qDNH)
  • Z-: Z-direction performance grade, such as Z15, Z25. (e.g. Q370qDNHZ15)

Q370q series steel offers high strength, excellent toughness, and weldability, with strong impact, fatigue, and low-temperature resistance. It is widely used in critical bridge components, including beams, trusses, and decks, ensuring durability and load-bearing capacity under harsh conditions.

Characteristics of Q370q Series Steel

  • High strength and toughness
  • Good weldability and machinability
  • Resistant to atmospheric corrosion
  • Suitable for low-temperature environments
  • Used in heavy structures like bridges and ships

Chemical Compositions

ElementQ370qD (%)Q370qE (%)
Carbon (C)≤ 0.14≤ 0.14
Silicon (Si)≤ 0.55≤ 0.55
Manganese (Mn)≥ 1.00 – ≤ 1.60≥ 1.00 – ≤ 1.60
Phosphorus (P)≤ 0.025≤ 0.020
Sulfur (S)≤ 0.020≤ 0.010
Chromium (Cr)≤ 0.30≤ 0.30
Nickel (Ni)≤ 0.30≤ 0.30
Copper (Cu)≤ 0.30≤ 0.30
Nitrogen (N)≤ 0.008≤ 0.008
Titanium (Ti)0.006 – 0.0300.006 – 0.030
Vanadium (V)0.010 – 0.0800.010 – 0.080
Niobium (Nb)0.010 – 0.0900.010 – 0.090
Boron (B)≤ 0.0005≤ 0.0005
Aluminum (Al)0.010 – 0.0450.010 – 0.045
Hydrogen (H)≤ 0.0002≤ 0.0002

Note:

  • According to standard GB/T 714-2015.
  • Al, Nb, V, and Ti can be added individually or in combination. If combined, at least one element must meet the table’s minimum limit, and the total of Nb + V + Ti ≤ 0.22%.
  • Total aluminum content must be 0.015% – 0.050%.
  • By mutual agreement, Mn content can be increased to 2.00%.
  • Analysis of B and H can be skipped if their residue in steel is guaranteed by the supplier.

Physical Properties

PropertyMetricImperial
Density7.85 g/cm³490.5 lb/ft³
Melting Point1450°C2642°F
Thermal Conductivity48 W/m·K27.7 BTU/(hr·ft·°F)
Electrical Conductivity6.99 MS/m6.99 MS/m
Specific Heat Capacity486 J/(kg·K)0.116 BTU/(lb·°F)
Thermal Expansion Coefficient12 × 10⁻⁶ /K6.7 × 10⁻⁶ /°F
Electrical Resistivity143 nΩ·m143 nΩ·m

Mechanical Properties

Thickness (mm)Yield Strength (MPa)Tensile Strength (MPa)Elongation (%)Impact Temperature (°C)Impact Energy (Akv J)
≤50≥370≥510≥20-20/-40 (Q370qD/Q370qE)≥41 (longitudinal)
50-100≥360≥510≥20-20/-40 (Q370qD/Q370qE)≥41 (longitudinal)

Industries & Applications

IndustryApplication
ConstructionBridges, Overpasses, Steel Structures, Railings
ShipbuildingDeck Plates, Hull Structures, Bulkheads, Support Beams
Energy & PowerWind Turbine Towers, Oil Platforms, Power Poles, Transmission Towers
TransportationRailway Tracks, Train Frames, Crane Beams, Highway Guardrails
Heavy MachineryExcavator Arms, Loader Frames, Crane Booms, Forklift Components

Machining

Heat Treatment

  • Normalizing: Heat to 880–920°C, then air cool.
  • Annealing: Heat to 750–800°C, hold, then slow furnace cool.
  • Quenching: Heat to 850–880°C, quench in water or oil.
  • Tempering: Reheat to 500–600°C, hold, then air cool.

Surface Finish

  • Shot blasting: Removes rust and scale, improving surface adhesion.
  • Pickling: Uses acid to clean the surface and remove oxides.
  • Galvanizing: Coats with a protective zinc layer to prevent corrosion.
  • Painting/Coating: Adds protective or decorative layers.
  • Phosphating: Prepares surface for further coating and enhances corrosion resistance.
  • Polishing: Smoothens the surface to improve aesthetics and reduce friction.

*Customization is available upon request.

Our Service

SteelPRO Group – manufacturer and solution provider for special steel, offering multi-industry application solutions and customised services, 100% quality free, accompanying customers in their growth!

Our Quality Control

  • Roundness
  • Tolerance
  • Microstructure
  • Non-Destructive Testing
  • Destructive Testing
  • Process Control

Service Integration Processing

  • Welding
  • Metal Fabrication
  • CNC Machining
  • Lathe
  • Forming

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