Q345B Low Alloy High Strength Structural Steel China Suppliers Factory
Q345B is a low-alloy, high-strength structural steel manufactured to the Chinese GB/T 1591 standard. With carbon content below 0.2%, this grade balances strength, weldability, and toughness for demanding industrial and structural applications.
With a designated yield strength of approximately 345 MPa, Q345B steel is used in bridges, marine vessels, high-rise buildings, and pressure vessels. Its strength can also help reduce the weight of components such as vehicle girders and chassis parts while maintaining structural performance.
Q345B Steel Specifications
| Material Grade | Q345B / Q355B (GB/T 1591) | Material Density | 7.85 g/cm³ |
|---|---|---|---|
| Yield Strength | 345 MPa | Tensile Strength | 470-630 MPa |
| Available Thickness | 0.1mm - 300mm | Available Width | 0.6m - 3m |
| Available Length | 4m - 12m (Customizable) | Production Technique | Hot Rolled |
| Applicable Standards | GB, ASTM, AISI, DIN, JIS, EN | Quality Grades | Q345A, B, C, D, E |
Key Benefits of Q345B Structural Steel
High Yield Strength
A 345 MPa yield point supports structural stability in applications subject to significant loads.
Potential for Weight Reduction
Its strength-to-weight characteristics can help reduce material use in applications such as chassis and girders.
Good Weldability
Carbon content below 0.2% supports good welding performance for structural fabrication.
Broad Application Range
Suitable for applications including bridges, ships, pressure vessels, and automotive structural components.
Multiple Thickness Options
Available thicknesses range from 0.1mm to 300mm to support different project requirements.
Standards and Grade Options
The product information references GB/T 1591-2008 and 2018 standards and lists Q345A, Q345B, Q345C, Q345D, and Q345E grades.
Q345B Steel Product Gallery
Production and Customization Capabilities
Large-Scale Production
The stated annual production capacity is 10 million tons, supporting supply for large-scale projects.
Medium- and Thick-Plate Lines
Production facilities include two 3500mm medium- and thick-plate lines for heavy-duty requirements.
Heat Treatment Facilities
Dedicated quenching and tempering lines are used to optimize steel hardness and toughness.
Hot-Rolling and Wire Rod Lines
Production resources include 1250mm hot-rolled coil and high-speed wire rod lines.
The facility is described as a key plate production base in Hebei Province, China.
Custom Product Options
Custom lengths, widths, and thicknesses can be arranged to meet customer specifications.
Q345B Steel Compared with Ordinary Carbon Steel
| Performance Metric | Ordinary Carbon Steel | Q345B Low-Alloy Steel | Potential Project Benefit |
|---|---|---|---|
| Yield Strength | Low / Standard | High (345MPa) | Greater load capacity |
| Material Weight | Heavy | Optimized / Lighter | Potentially lower logistics costs |
| Structural Life | Standard | Extended | Potential for reduced maintenance costs |
| Welding Efficiency | Variable | Superior | Potentially faster construction |
| Overall ROI | Baseline | High Efficiency | Long-term value potential |
Frequently Asked Questions About Q345B
“Q” represents the Chinese Pinyin term “qu fu dian,” meaning “yield point.” The grade designation is based on the steel’s minimum yield strength.
In general, Q345B yield strength decreases as material thickness increases. Check the relevant technical datasheet for values applicable to the specific thickness.
Common applications include bridges, vehicle chassis, marine vessels, high-rise building frameworks, and pressure vessels.
Q355 is associated with the updated GB/T 1591-2018 standard, which replaced GB/T 1591-2008 for Q345. The grades are similar, while Q355 reflects updated testing and classification requirements.
Yes. Q345B can be used for automotive components such as transmission shafts and vehicle girders, where its strength can help reduce overall vehicle weight while maintaining structural performance.
The listed GB/T 1591 quality grades are Q345A, Q345B, Q345C, Q345D, and Q345E.