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Carbon Steel Square Tube
What Are Carbon Steel Square Tubes?
Carbon steel square tubes are hollow, cold-formed or hot-formed steel profiles with a square cross-section, manufactured from carbon steel coils or plates through Electric Resistance Welding (ERW) or seamless processes . The carbon content typically ranges from 0.05% to 0.25% for mild steel grades, providing an excellent balance of strength, weldability, and cost-effectiveness.
Key Specifications (Customizable for Your Production & Project Needs)
We provide standard specifications complying with international standards (ASTM, EN, GB, JIS) and support full customization to match your production equipment, installation requirements, and project scenarios. The following are the common specifications most carbon steel square tube buyers choose, covering mainstream application scenarios:
| Item | Specification Range | Common Standards | Buyer-Focused Note |
| Side Length | 20mm×20mm - 200mm×200mm (common), up to 500mm×500mm (customized) | ASTM A500, EN 10219, GB/T 3091, JIS G3466 | Side length tolerance ≤ ±0.1mm, ensuring uniform structure and easy assembly |
| Wall Thickness | 1.0mm - 12mm (common), up to 25mm (customized) | ASTM A500, EN 10219, GB/T 3091, JIS G3466 | Customizable thickness to balance load-bearing capacity, weight and cost |
| Length | 3m - 12m (standard), customizable (cut to length) | International Trade Standard | Cut-to-length service to reduce on-site cutting waste and processing time |
| Surface Treatment | Mill Finish, Hot-Dip Galvanized, Electro-Galvanized, Paint-Coated | International Trade Standard | Galvanized/paint-coated for anti-rust, suitable for outdoor/harsh environments |
Surface Finish & Protection Options (Your Application Matters)
| Surface Type | Description | Best Suited For |
| Black / Mill Finish | As-rolled with light oxide scale; most economical | Indoor structures, further fabrication, painting in-house |
| Pickled & Oiled | Scale removed, oiled surface | Clean surface ready for welding or painting |
| Pre-Galvanized | Zinc coating 30-275g/m² applied before forming | Light to medium corrosion protection, indoor/outdoor use |
| Hot-Dip Galvanized (HDG) | Zinc coating 200-600g/m² applied after fabrication | Maximum corrosion protection for outdoor and harsh environments |
| Painted / Lacquered | Primed or finished color coating | Decorative applications, color-coded systems |
| Anti-Rust Oiled | Light oil coating for temporary protection | Storage and transit protection |
Applications: Where Our Carbon Steel Square Tubes Excel
| Industry | Applications | Preferred Specifications |
| Building & Construction | Structural columns, roof trusses, curtain wall supports, mezzanine floors | ASTM A500 Gr. B/C, S355, HDG coated |
| Infrastructure | Highway sign supports, guardrails, bridge railings, pedestrian bridges | Hot-dip galvanized, heavy wall thickness |
| Transportation | Truck trailers, container frames, bus shelters, railway platforms | High-strength grades, corrosion-resistant finish |
| Agriculture | Greenhouse frames, livestock equipment, grain bin supports, fencing | Pre-galvanized or painted, cost-effective grades |
| Industrial Equipment | Machine bases, conveyor frames, workstations, material handling racks | Precision dimensions, heavy wall thickness |
| Solar Energy | Solar panel mounting structures, tracker frames | ASTM A500, HDG coated for outdoor durability |
| Furniture & Fixtures | Table legs, shelving units, display racks, bench frames | Cold-formed, smooth finish, painted or bright |
| Security & Fencing | Security barriers, gate frames, bollards, perimeter fencing | Heavy wall, galvanized or painted |
FAQ (For Carbon Steel Square Tube Buyers)
Q1: What are the key factors affecting the load-bearing capacity of carbon steel square tubes, and how do you ensure they meet our project requirements?
A1: The load-bearing capacity of carbon steel square tubes is mainly determined by side length, wall thickness, material grade, and manufacturing precision. We strictly control the side length and wall thickness tolerance within ±0.1mm to ensure uniform stress distribution.
For high-load scenarios (e.g., building frames), we select high-strength grades (ASTM A500 Gr.C, GB Q355B) and adopt high-frequency welded or seamless processes to ensure weld strength (≥95% of base metal). Each batch of structural square tubes undergoes tensile and bending tests, and we provide detailed mechanical property reports to confirm compliance with your project’s load-bearing requirements.
Q2: How do you prevent carbon steel square tubes from rusting, deforming, or being scratched during transportation and storage?
A3: We adopt professional packaging and protection measures: each tube is wrapped with PE moisture-proof film and kraft paper to prevent rust and scratches; for long lengths, we use steel brackets and wooden pallets to avoid deformation. For sea transportation, we add waterproof covers, desiccants, and anti-collision buffers, and fix the tubes firmly to prevent collision and extrusion during transportation.
We also mark "Handle with Care", "Moisture-Proof", and "Anti-Collision" on the packaging to ensure the tubes arrive in intact condition and can be directly installed or processed.
Q3: What is the difference between hot-rolled and cold-rolled carbon steel square tubes, and how should we choose based on our application?
A4: Hot-rolled carbon steel square tubes (produced at 1000℃+ ) have higher thickness tolerance, good toughness, and lower cost, suitable for general structural applications (e.g., scaffolding, greenhouse frames).
Cold-rolled carbon steel square tubes (produced at room temperature) have higher dimensional accuracy, smoother surface, and better flatness, suitable for decorative applications (e.g., curtain walls, handrails) and precision structural components. We can recommend the most suitable type based on your application scenario, appearance requirements, and cost budget.
Contact our sales team today for a quotation or to discuss your project requirements. We are committed to providing high-quality carbon square tube that meet your exact specifications and delivery deadlines.
Your trusted partner in carbon steel solutions.For further technical information, pricing, or customization, please contact our sales team:
Tel/WA/Wechat: +86 13225105678
Email: sales01@duohessplate.com
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