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Carbon Steel Round Bar Q235B Q345B Used for Structural Steel Fabrication
Product Spotlights
High-quality carbon steel round bars Q235B and Q345B for structural steel fabrication. Precise diameters (10-300mm), customizable lengths, and surface finishes. Excellent weldability and mechanical properties. ISO9001 certified, factory-direct from a reliable exporter with US$50M+ annual export value. Competitive pricing and global shipping.
Negotiable
MOQ: 1 Ton (Price negotiable depending on order volume and customization)
Key Specifications
Get Latest Price
Application:
Other, Structural steel fabrication
Standard:
Other, GB/T 700-2006
material:
Carbon Steel
Payment & Shipping
Payment Methods:
Port of Shipment:
Qingdao Port
Delivery Detail:
7 days
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Application
Other, Structural steel fabrication
Standard
Other, GB/T 700-2006
material
Carbon Steel
grade
Q235B / Q345B
diameter
Available from 10mm to 300mm (custom sizes)
length
6m, 12m or custom lengths
shape
Round Bar
surface
Black, Bright, or Galvanized (optional)
certification
ISO9001
trade term
FOB, CIF, CFR
Welcome to Hemaokang Steel (Shandong) Co., Ltd. – your reliable partner for high-quality carbon steel round bars. Our Q235B and Q345B round bars are specifically designed for structural steel fabrication, offering exceptional strength, weldability, and cost-effectiveness. With an annual export value of US$50 million to US$100 million and a team of 51–100 experienced professionals, we ensure consistent quality and timely delivery to clients across North America, Europe, Asia, and beyond. Backed by ISO9001 certification, our products meet rigorous international standards, making them the preferred choice for bridges, buildings, machinery, and heavy structures.
Product Features & Technical Specifications
- Material & Grade: Available in both Q235B (general structural grade) and Q345B (higher strength grade) carbon steel, ensuring versatility for various load-bearing requirements.
- Dimensional Accuracy: Manufactured with precise tolerances (diameter tolerance ±0.5mm, length tolerance ±5mm) to guarantee smooth fabrication and assembly.
- Surface Finish: Choose from black (mill scale), bright (drawn), or hot-dip galvanized finish to match your application needs. Custom surface treatments available upon request.
- Weldability & Machinability: Excellent weldability due to low carbon content and controlled chemical composition. Ideal for cutting, drilling, bending, and welding operations.
- Mechanical Properties: Q235B offers yield strength ≥235 MPa, tensile strength 370–500 MPa; Q345B offers yield strength ≥345 MPa, tensile strength 490–675 MPa. Both provide good ductility and impact resistance.
- Length Options: Standard 6m or 12m bars, with custom lengths up to 18m available. We also offer cut-to-size services for your convenience.
| Parameter | Q235B Round Bar | Q345B Round Bar |
|---|---|---|
| Diameter Range | 10mm – 300mm | 10mm – 300mm |
| Yield Strength (min) | 235 MPa | 345 MPa |
| Tensile Strength | 370–500 MPa | 490–675 MPa |
| Elongation (min) | 26% | 21% |
| Chemical Composition | C ≤0.20%, Si ≤0.35%, Mn ≤1.40%, P ≤0.045%, S ≤0.045% | C ≤0.20%, Si ≤0.55%, Mn ≤1.70%, P ≤0.040%, S ≤0.040% |
Key Advantages for Structural Fabrication
- High Strength-to-Weight Ratio: Q345B provides higher strength, allowing lighter structures without sacrificing load capacity. Q235B offers a cost-effective solution for less demanding applications.
- Versatile Application: Perfect for building frames, trusses, columns, beams, bridges, and heavy machinery components. Both grades are widely used in construction, infrastructure, and industrial projects.
- Customizable Options: We offer custom diameters, lengths, and surface treatments to meet your specific project requirements. Minimum order quantities are flexible.
- Consistent Quality: Every batch is tested for chemical composition and mechanical properties. Our ISO9001 quality management system ensures traceability and reliability.
- Competitive Pricing: As a direct manufacturer with high export volume, we provide factory-direct prices and favorable terms (FOB, CIF, CFR).
Trust & Reliability
Hemaokang Steel (Shandong) Co., Ltd., established in 2025, has rapidly grown into a leading exporter of carbon steel products. With an annual export value between US$50 million and US$100 million, we have served clients in over 15 major markets including North America, Europe, Southeast Asia, Africa, and Oceania. Our 51–100 dedicated employees ensure that every order is handled with professionalism and care. We are ISO9001 certified, demonstrating our commitment to quality and continuous improvement. Whether you need standard round bars or customized solutions, our team is ready to provide prompt quotations, technical support, and reliable logistics. Contact us today to discuss your structural steel fabrication needs – we guarantee a responsive and trustworthy partnership.
Frequently Asked Questions
- What is the difference between Q235B and Q345B round bars? Q235B is a general-purpose structural steel with lower yield strength (235 MPa), while Q345B offers higher strength (345 MPa) and better performance under heavy loads. Q345B is recommended for critical structural applications.
- Can you provide third-party inspection? Yes, we can arrange inspections by SGS, BV, or other accredited agencies at your request. Additional costs may apply.
- What are the available surface treatments? We offer black (as-rolled), bright (drawn), and hot-dip galvanized finishes. Pickled and oiled surface is also available upon request.
- Do you supply small quantities for samples? Yes, we can supply sample lengths (e.g., 1m) for testing. Please contact our sales team for sample pricing and lead time.
- How is the packaging for export? Standard packaging includes bundling with steel straps, protective wrapping, or in bulk containers. We can also customize packaging according to your requirements.
- What is the typical delivery time? For standard sizes and quantities, delivery is usually 15–30 days after order confirmation. Custom sizes may require 25–40 days.
- Are your products compliant with international standards? Our round bars are manufactured according to Chinese GB/T standards (GB/T 700-2006 for Q235B, GB/T 1591-2018 for Q345B). They are also suitable for equivalent ASTM A36 (Q235B) and ASTM A572 Grade 50 (Q345B) applications.
- Do you offer technical support for material selection? Absolutely. Our experienced engineers can help you choose the right grade and size for your specific project. Just provide your requirements and we will advise.
Send Inquiry to This Supplier
1Yr
Year Established
2025
Annual Export Value
US$50 Million - US$100 Million
Total Employees
51 - 100 People
Product Certifications
ISO9001
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