Product Overview
Carbon steel square tube (also called square hollow section, SHS) is a cold-formed welded profile with a square cross-section and uniform wall thickness. Formed from hot-rolled strip on high-frequency welded tube mills, square tubes combine high torsional rigidity, clean architectural lines, and excellent compression performance — making them the default choice for structural frames, posts, racking, and gates. Huaxia-Steel supplies square and rectangular hollow sections from NPS 15 × 15 mm up to 400 × 400 mm in ASTM A500, EN 10219, JIS G3466, and GB/T 6728 grades, with factory-direct pricing for export.
Specifications
| Parameter | Range | Standard / Tolerance |
|---|---|---|
| Section size (square) | 15 × 15 – 400 × 400 mm | GB/T 6728 / EN 10219 dimension tables |
| Rectangular sections (RHS) | 20 × 10 – 500 × 300 mm | Same standards, aspect ratio to 4:1 |
| Wall thickness | 1.0 – 16 mm | ± 5 – 10% per standard, gauge-controlled strip |
| Standard lengths | 5.8 m, 6 m, 12 m (custom up to 18 m) | Length tolerance +10 / −0 mm typical |
| Weight per meter | ~0.7 – 180 kg/m | Theoretical, ± 3 – 5% per lot |
| Corner radius | 1.0 – 2.0 × wall thickness | Per forming roll design |
| Cutting | Cold saw cut, burr-free ends | Cut-to-length service available |
Available Grades
| Standard | Grades | Min Yield | Typical Market |
|---|---|---|---|
| ASTM A500 | Gr A, B, C | 205 – 290 MPa | North/South America |
| EN 10219 | S235JRH, S275J0H, S355J2H | 235 – 355 MPa | Europe, Middle East |
| JIS G3466 | STKR400, STKR490 | 245 – 325 MPa | Japan-spec projects |
| GB/T 6728 | Q195 – Q355B | 195 – 355 MPa | China, general export |
Manufacturing Standards
- Process: high-frequency ERW — strip coil roll-formed to square, seam welded, then sized through shaping stands; weld seam heat-treated on request.
- Dimensional tolerances: side width ± 1%, out-of-square ≤ 2% of side, wall ± 5 – 10% per GB/T 6728 / EN 10219.
- Straightness: ≤ 2 mm per meter typical (tighter to order for racking and precision frames).
- Surface: self-color (mill), oiled, primer-painted, or hot-dip galvanized per ISO 1461 / ASTM A123 on request.
Applications
- Structural columns and beams for sheds, canopies, and light steel buildings
- Warehouse racking, pallets, and material handling frames
- Fence posts, gates, handrails, and balustrades
- Truck bodies, trailer chassis, and agricultural equipment frames
- Street furniture, solar mounting structures, and sign supports
Quality Assurance
- EN 10204 3.1 mill test certificate with heat number traceability
- Tensile and flatten tests on weld seam per lot; dimensional inspection reports
- Weld seam NDE (eddy current) available on request for structural grades
- Optional third-party inspection (SGS, BV, TÜV) before shipment
- Coating thickness measurement report for galvanized orders
Packaging & Shipping
- Standard export bundles, steel-strapped with nylon corner protection to preserve tube surfaces
- End caps and plastic wrapping available; steel tags with grade, size, heat number, bundle count
- 20ft container (max 5.8 m lengths) or bulk vessel for 12 m lengths
- Oiled or VCI protection for sea freight; loading photos and weight tally before departure
Huaxia-Steel supplies carbon steel square and rectangular hollow sections to ASTM A500, EN 10219, JIS G3466, and GB/T 6728 — factory-direct pricing, full certification, and cut-to-length service. Send us your section list and grade for a same-week quotation.
