Category | Type | Description |
By Section Shape | Square Tube | Square cross-section, equal side lengths |
| Rectangular Tube | Rectangular cross-section, different side lengths |
By Manufacturing Process | Welded (ERW) | High-frequency welded, cost-effective, most common |
| Seamless | Hot-rolled or cold-drawn, higher pressure capacity |
By Surface Finish | Bare Steel (Black) | As-rolled scale surface, lowest cost |
| Hot-dip Galvanized | Thick zinc coating, excellent corrosion resistance |
| Powder-coated / Painted | Custom colours, decorative and weather-resistant |
By Material | Q195 / Q235B / Q355B | Different strength grades |
Common Specifications
Square Tube – Common Sizes (Side Length × Wall Thickness)
Side (mm) | Thick (mm) | Weight (kg/m) | Side (mm) | Thick (mm) | Weight (kg/m) |
20×20 | 1.5 | 0.85 | 80×80 | 3.0 | 7.13 |
25×25 | 2.0 | 1.38 | 80×80 | 4.0 | 9.33 |
30×30 | 2.0 | 1.70 | 100×100 | 3.0 | 9.00 |
30×30 | 3.0 | 2.45 | 100×100 | 4.0 | 11.80 |
40×40 | 2.0 | 2.30 | 100×100 | 5.0 | 14.50 |
40×40 | 3.0 | 3.35 | 120×120 | 4.0 | 14.30 |
50×50 | 2.0 | 2.93 | 120×120 | 5.0 | 17.60 |
50×50 | 3.0 | 4.31 | 150×150 | 5.0 | 22.50 |
50×50 | 4.0 | 5.60 | 150×150 | 6.0 | 26.70 |
60×60 | 3.0 | 5.23 | 200×200 | 6.0 | 36.20 |
60×60 | 4.0 | 6.80 | 200×200 | 8.0 | 47.40 |
Rectangular Tube – Common Sizes (Long Side × Short Side × Thickness)
Size (mm) | Thick (mm) | Weight (kg/m) | Size (mm) | Thick (mm) | Weight (kg/m) |
30×20 | 2.0 | 1.42 | 80×60 | 4.0 | 8.00 |
40×20 | 2.0 | 1.76 | 100×50 | 3.0 | 6.70 |
40×30 | 3.0 | 2.89 | 100×50 | 4.0 | 8.80 |
50×30 | 2.0 | 2.37 | 120×60 | 4.0 | 10.60 |
50×40 | 3.0 | 3.87 | 120×80 | 5.0 | 14.20 |
60×40 | 3.0 | 4.28 | 150×100 | 5.0 | 18.20 |
60×40 | 4.0 | 5.62 | 150×100 | 6.0 | 21.60 |
80×40 | 3.0 | 5.22 | 200×100 | 6.0 | 26.60 |
80×40 | 4.0 | 6.84 | 200×150 | 8.0 | 42.10 |
Non-standard side lengths, wall thicknesses, and custom lengths (standard 6m, cut-to-length available) can be produced upon request. Galvanized or coated finishes are available.
Materials & Standards
Material | Yield Strength (MPa) | Tensile Strength (MPa) | Chinese Standard | International Equivalent |
Q195 | ≥195 | 315-430 | GB/T 6728 | ASTM A500 Gr.A |
Q235B | ≥235 | 370-500 | GB/T 6728 | ASTM A500 Gr.B / EN 10219 S235JR |
Q355B | ≥355 | 470-630 | GB/T 6728 | ASTM A500 Gr.C / EN 10219 S355JR |
Welded square/rectangular tubes are supplied to GB/T 6728 (cold-formed sections) or GB/T 3094 (seamless), and can also be produced to ASTM A500, EN 10219, JIS G3466, and other international standards.
Surface Finishes
Finish | Features | Application |
Bare Steel (Black) | As-rolled scale surface, lowest cost | Indoor structures, painting after welding |
Hot-dip Galvanized | Zinc coating ≥40μm, excellent corrosion resistance | Outdoor, coastal, high-humidity areas |
Electro-galvanized | Thin coating, bright surface | Indoor mild protection |
Powder-coated / Painted | Custom colours, decorative and weather-resistant | Aesthetic or special anti-corrosion needs |
Key Advantages
Advantage | Description |
Efficient Section | Square/rectangular shape provides good bending and torsional performance, high material utilization |
Complete Size Range | Square side from 20–200mm, various rectangular combinations, wall thickness 1.5–8mm, ample stock |
Precise Dimensions | Cold-formed to tight tolerances, square cut ends |
Easy Fabrication | Easy to cut, drill, weld – suitable for prefabrication and site assembly |
Multiple Anti-corrosion Options | Can be formed from galvanized coil or galvanized/coated after forming |
Flexible Customization | Non-standard sizes and cut-to-length available |
Export-Ready Packaging | Securely bundled, waterproof and rust-proof for ocean freight |
Application Scenarios
Field | Typical Uses |
Building Structures | Steel plant frames, platform beams/columns, curtain wall framing |
Bridge Works | Bridge railings, support members |
Machinery Manufacturing | Equipment bases, conveyor frames, lifting platforms |
Vehicles & Shipbuilding | Vehicle body frames, truck bodies, hull structures |
Agricultural Facilities | Greenhouse frames, livestock enclosures |
Municipal Facilities | Guardrails, street lamp poles, traffic sign poles, carports |
Furniture & Decoration | Exhibition racks, shelving, furniture frames |
Packaging & Shipping
Packaging Method | Description |
Bundled Packing | Bundled by size with steel straps/wire, timber supports underneath |
Waterproofing | Wrapped with waterproof woven fabric or PVC film |
End Protection | Plastic caps to prevent end deformation (optional) |
Custom Marking | Labels or stenciled markings as per customer request |
Loading Port | Qingdao, Tianjin – we can arrange ocean freight |
supplies square and rectangular tubes in materials Q195/Q235/Q355, with hot-dip galvanizing or powder coating, and supports non-standard and cut-to-length orders. For inquiries and quotations, please contact us.
