Q345 Q355 S355JR High-Strength Low Alloy Carbon Steel Coil Hot Rolled 1.5mm-20mm for Structural Engineering

Our Q345 Q355 S355JR high-strength low alloy carbon steel coils represent the optimal balance of strength, weldability, and cost-effectiveness for demanding structural engineering projects. Manufactured through advanced hot rolling technology with precise temperature control and accelerated cooling, these coils achieve superior mechanical properties while maintaining excellent formability. The controlled rolling process refines the grain structure, resulting in homogeneous material properties throughout the coil length. Whether you are constructing multi-story buildings, highway bridges, offshore platforms, or industrial heavy equipment, our high-strength carbon steel coils provide the reliability and performance that modern engineering demands. With decades of metallurgical expertise and a commitment to international quality standards, we supply material that consistently exceeds project specifications while offering competitive pricing and dependable lead times.

• Superior Tensile Strength: Our Q345 and Q355 low alloy carbon steel coils deliver yield strength from 345 MPa to 355 MPa with tensile strength reaching 470-630 MPa, making them ideal for heavy structural applications where load-bearing capacity is critical. Each coil undergoes rigorous mechanical testing to ensure consistent performance across the entire length.
• Excellent Weldability: Low carbon equivalent values (CEV typically below 0.45) ensure outstanding weldability without preheating for most thicknesses. This reduces fabrication costs and speeds up construction timelines for bridges, high-rise buildings, and industrial frameworks where on-site welding is essential.
• Wide Dimensional Range: Available in thickness from 1.5mm to 20mm and widths from 600mm to 2000mm, our high-strength coils cover virtually all structural steel requirements. Custom slitting and cut-to-length services provide ready-to-use material that minimizes waste and processing time at your facility.
• Mill Test Certification: Every coil ships with complete EN 10204 3.1 or 3.2 mill test certificates documenting chemical composition, mechanical properties, and dimensional tolerances. Third-party inspection by SGS, BV, or TUV is available upon request for projects requiring independent verification.
• Cost-Effective Material Solution: Compared to standard Q235 grades, Q345/Q355 high-strength steel allows for thinner sections while maintaining equivalent load capacity, reducing total steel weight by up to 20%. This translates directly to lower material costs, reduced transportation expenses, and lighter foundation requirements.
• Weathering Resistance: Enhanced atmospheric corrosion resistance makes these coils suitable for outdoor structures exposed to the elements. The alloy composition includes controlled amounts of copper, chromium, and nickel that form a protective patina over time, eliminating the need for painting in many applications.
• Stock Availability & Fast Delivery: With 80,000 tons monthly production capacity and extensive warehouse inventory, we maintain ready stock of popular grades and sizes. Standard orders ship within 7-15 working days, ensuring your construction schedule stays on track without material delays.

Q345 and Q355 high-strength carbon steel coils are extensively used in structural engineering applications where superior load-bearing capacity is required. Primary applications include steel frameworks for high-rise commercial and residential buildings, highway and railway bridge girders, offshore platform structural components, industrial plant and factory steel structures, transmission towers and telecommunication masts, heavy machinery frames and bases, shipbuilding structural elements, pressure vessel shells, and mining equipment components. The combination of high yield strength and excellent weldability makes these grades the preferred choice for projects designed to international codes including Eurocode 3, AISC 360, and GB 50017. Engineers value the predictable mechanical properties that allow for optimized section designs, reducing overall steel tonnage while meeting or exceeding safety factors.

Every coil is precision-wrapped with anti-rust VCI paper and waterproof polyethylene film, then secured with radial and circumferential steel strapping bands. Wooden pallets or steel cradles provide stable support during handling and transportation. Inner and outer protective steel rings prevent edge damage and maintain coil geometry. For container shipping, coils are loaded with timber bracing and steel lashing to prevent movement during transit. Each shipment includes detailed packing lists, mill test certificates, and fumigation certificates as required. Our quality assurance program encompasses 100% dimensional inspection, mechanical testing per heat, ultrasonic testing for internal defects on request, and surface quality verification throughout the production process. We stand behind every shipment with a comprehensive warranty covering material defects and specification compliance.