Product Overview
Q345qD is a special low-alloy high-strength structural steel exclusively developed for bridge construction, complying with GB/T 714-2015 and GB/T 1591-2018 standards. Grade explanation:
- Q = Yield strength; 345 = Minimum yield strength 345MPa
- q = Bridge steel
- D = D quality grade with -20℃ Charpy V-notch impact test requirement
Compared with Q345qC (0℃ impact), Q345qD has far better low-temperature anti-brittle performance, suitable for temperate and northern cold region bridge projects. It integrates high strength, low temperature toughness, atmospheric corrosion resistance and perfect welding performance, widely used for all main load-bearing components of steel bridges and heavy industrial structures.
Why Choose Q345qD Over Ordinary Q345 Carbon Steel?
One-stop bridge steel procurement
Special bridge-oriented formulation: Microalloyed element design strictly controlled for low-temperature impact, ordinary Q345 has no guaranteed -20℃ toughness.
Standardized ultrasonic inspection: Plates over 20mm thickness pass Class II UT flaw detection to eliminate internal lamination defects.
Complete engineering certification: Full mill test certificates for bridge authority inspection approval.
Chemical Composition (Mass Fraction, Max Value, GB/T 714-2015)
| Element | C | Si | Mn | P | S | Nb | V | Ti | Al(min) |
|---|---|---|---|---|---|---|---|---|---|
| Content | ≤0.18 | ≤0.50 | 1.20~1.60 | ≤0.025 | ≤0.025 | ≤0.07 | ≤0.15 | ≤0.020 | 0.015 |
Core Mechanical Properties by Thickness
| Plate Thickness | Min Yield Strength(MPa) | Tensile Strength(MPa) | Min Elongation A5 | -20℃ Longitudinal Impact Energy KV2(J) | 180° Cold Bend Test |
|---|---|---|---|---|---|
| ≤50mm | 345 | 490~630 | 20 | ≥120 | d=2a |
| 50~100mm | 335 | 490~630 | 20 | ≥120 | d=3a |
| 100~150mm | 305 | 490~630 | 20 | ≥120 | d=3a |
Applications | Main Engineering Scenarios
- Highway Bridge Construction Cable-stayed bridge box girders, suspension bridge stiffening beams, arch bridge ribs, bridge deck crossbeams, pier load-bearing components.
- Railway Steel Bridges Steel truss girders, train load-bearing beams, railway bridge support frames, anti-fatigue main structural plates.
- Large-Span Industrial Building Structures Factory heavy load beams, column supports, exhibition venue large-span roof trusses, logistics warehouse bearing frames.
- Ship & Offshore Auxiliary Structures Ship deck load-bearing plates, hull reinforcement frames, offshore platform auxiliary structural parts.
- Mining & Heavy Equipment Manufacturing Mining machinery heavy load brackets, large transport vehicle chassis structural plates, hydraulic support components.
Use Problems
When using Q345qD steel, you need to pay attention to the following problems:
1. Welding: Q345qD steel has good welding performance, but in the welding process, you need to pay attention to the selection of suitable welding materials and technology to avoid cracks and deformation.
2. Cutting: Due to the high hardness of Q345qD steel, you need to use the appropriate equipment and technology when cutting to avoid cracks and deformation.
3. Rust prevention treatment: Q345qD steel needs to pay attention to prevent rusting in the process of use, which can be protected by coating, rust-proof oil and other means.
why choose us?
Mass Spot Inventory: Large stock of standard Q345qD thicknesses for fast delivery within 3~7 working days.
Custom Cutting Service: CNC blanking, beveling and forming processing to reduce client secondary machining cost.
Global Export Experience: Products exported to over 50 countries including Russia, Turkey, India, Southeast Asia and Middle East.
Factory Direct Price: Self-owned rolling mill without intermediate markup, preferential pricing for large bridge project bulk orders.
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our Partners
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User Evaluation
Mr. Wang Qiang
Wuhan Bridge Engineering Group
Mr. Dmitry Sokolov
Moscow Railway Construction Company Russia
Ms. Zhang Mei
Shandong Steel Structure Factory
FAQ
01.What is the difference between Q345qC, Q345qD and Q345qE?
The core difference is impact test temperature: Q345qC at 0℃, Q345qD at -20℃, Q345qE at -40℃. Q345qD fits most temperate zone highway and railway bridge projects, balancing cost and low-temperature performance.
02.Is Q345qD suitable for all welding processes?
03.What delivery states can Q345qD be supplied in?
04.Can you provide UT ultrasonic inspection reports for thick Q345qD plates?
Yes. All plates over 20mm thickness are 100% ultrasonic tested with Class II acceptance standard, complete UT test reports attached to each batch delivery document.
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