Q355B Q460 Q690 Box Section Steel Customized Size Structural Solution EN 10219 ISO 9001

Box Section Steel (also known as box girder or hollow section steel) is a high-performance structural member with a closed rectangular or square cross-section, engineered for superior load-bearing capacity, torsional stiffness, and stability in complex force scenarios. Manufactured with Q355B/Q460/Q690 high-strength steel, this product is fabricated by welding two H-beams, steel plates, or rolling steel into a closed box shape (standard sizes: 200×200mm-1200×800mm, customized up to 1500×1000mm), ensuring yield strength ≥345MPa (Q355B) to ≥690MPa (Q690) and tensile strength ≥510MPa to ≥830MPa. Key features include closed cross-section design for exceptional torsional resistance (5-10x higher than H-beams), uniform force distribution to avoid stress concentration, and high lateral stability (resisting buckling under heavy loads). The surface is treated with hot-dip galvanizing (zinc layer thickness ≥100μm), fluorocarbon coating, or weathering steel finish, providing salt spray resistance ≥1200-1500 hours and adapting to coastal, industrial, and high-corrosion environments. It complies with GB/T 3094, EN 10219, and AISC 360 standards, supporting customization of cross-section shape (rectangular, square, or oval), wall thickness (8mm-50mm), and length (up to 30m per segment). Factory prefabrication rate ≥95% ensures precise welding (full-penetration welds with ultrasonic inspection) and dimensional accuracy (error ≤±0.8mm). Professional services include finite element analysis (FEA) for section optimization, torsional stability simulation, on-site installation guidance, and non-destructive testing (NDT) for weld quality.

Box Section Steel is a premium structural solution for high-demand projects requiring torsional stiffness, heavy load-bearing, and stability, widely used in high-rise buildings, bridges, and industrial facilities. Certified by GB/T 3094, EN 10219, and ISO 9001, it meets strict structural standards for critical applications. Typical applications include main beams and columns in super-tall buildings (skyscrapers, mixed-use complexes) and large-span structures (span ≥40m), bridge girders (long-span bridges, cable-stayed bridges, viaducts), heavy industrial equipment supports (steel mills, forging plants, crane runways), and special structures (stadium roofs, architectural canopies, offshore platforms). It is particularly essential for projects with complex force conditions—such as torsional loads (e.g., curved bridges), combined bending and axial loads (e.g., high-rise columns), or heavy dynamic loads (e.g., industrial machinery). The closed cross-section also makes it ideal for corrosion-prone environments, as the internal cavity can be sealed to prevent moisture penetration. The minimum order quantity is 5 tons for standard specifications or 1 set for customized structural components. Competitive project-based pricing and flexible delivery terms (15-40 workdays based on complexity) support critical construction schedules, while a monthly supply capacity of 1000 tons ensures timely delivery for large-scale projects. Customization options include corrosion-resistant upgrades (316L stainless steel, super duplex stainless steel) for coastal or chemical industrial environments, fire-resistant coating (fire resistance ≥2.5 hours) for high-rise public buildings, and ultra-high-strength Q960 steel for super-tall structures (height ≥300m) to reduce member size and structural weight.