25/05/2026
National Standard Carbon Steel Square and Rectangular Tubes - In Stock, Full Size Coverage, Suitable for Multiple Engineering Fields
For steel structure workshops, frame construction, and hardware processing, the straightness and wall thickness tolerance of square and rectangular tubes directly determine the structural stability of the project! Our supplied Q235B and Q355B carbon steel square and rectangular tubes are manufactured strictly according to the national standard GB/T 6728, directly from the source steel mill, with each batch accompanied by the original factory quality inspection report. They feature straight edges and corners, uniform wall thickness, excellent weldability, and load-bearing capacity and deformation resistance far exceeding ordinary products in the industry, making them a superior material choice for industrial production and engineering construction!
Full range of sizes and specifications in stock, one-stop solution for all your needs.
We maintain thousands of tons of standard specifications in stock, covering the entire range from small decorative pipes to large engineering structural pipes. We also support custom-made sizes and on-demand cutting:
Small Size Square and Rectangular Pipes (Side Length 10mm-50mm)
▪ Square Pipes: 10×10mm, 20×20mm, 30×30mm, 40×40mm, 50×50mm, Wall Thickness 0.5mm-3.0mm
▪ Rectangular Pipes: 20×30mm, 25×40mm, 30×50mm, Wall Thickness 0.8mm-3.0mm
Lightweight and easy to cut and weld, suitable for small frames and decorative components.
Medium-sized square and rectangular tubing (side length 60mm-150mm)
▪ Square tubing: 60×60mm, 70×70mm, 80×80mm, 100×100mm, 120×120mm, 150×150mm, wall thickness 2.0mm-6.0mm
▪ Rectangular tubing: 40×60mm, 50×80mm, 60×90mm, 80×120mm, 100×150mm, wall thickness 2.0mm-6.0mm Balancing strength and workability, it is the main material used for steel structure factory buildings and shelving construction.
Large-size square and rectangular tubes (side length 160mm-500mm)
▪ Square tubes: 160×160mm, 200×200mm, 250×250mm, 300×300mm, 400×400mm, 500×500mm, wall thickness 5.0mm-16mm
▪ Rectangular tubes: 150×200mm, 200×300mm, 250×400mm, wall thickness 5.0mm-16mm Custom sizes of larger diameter, thicker-walled square and rectangular tubes are available. These tubes offer strong load-bearing capacity, resistance to compression and deformation, and are suitable for large and heavy-duty structures.
All square and rectangular tubes are standard lengths of 6m/12m, but can be cut to any length from 1-12m upon request. Punching, bending, and stretch bending services are available, ensuring clean, burr-free cuts for immediate installation and processing.
Adaptable to multiple industries and scenarios, suitable for engineering and processing.
Our carbon steel square and rectangular tubes are rolled from high-quality low-carbon steel, offering stable mechanical properties, easy welding and cutting, and resistance to cracking. They are suitable for various industry scenarios:
✅ Steel Structure Engineering: Factory columns and beams, steel structure stadiums, warehouse space frames. Large and medium-sized square and rectangular tubes provide stable cross-sectional structures, strong load-bearing capacity, wind and earthquake resistance, meeting engineering acceptance standards, and maintaining their shape over long-term use.
✅ Municipal Engineering: Landscape pergolas, municipal railings, bus stop platform frames. Good corrosion resistance, easy painting, neat and aesthetically pleasing design, long service life, and low maintenance costs.
✅ Logistics and Warehousing: Heavy-duty racks, automated warehouses, storage platforms. Medium-sized square and rectangular tubes provide uniform load-bearing capacity, stable layer load without swaying, and will not deform when storing heavy objects.
✅ Machinery Manufacturing: Machinery equipment frames, engineering machinery booms, conveyor equipment supports. Good welding performance, easy processing, meeting strength standards, and impact resistance, suitable for various machinery production needs.
✅ **Decoration and Renovation Sector:** Display cabinet frames, stainless steel door frames, ceiling joists. Small-sized square and rectangular tubes are easy to cut and shape, with a smooth surface for easy spray painting and baking, resulting in both aesthetics and sturdiness.
✅ **Vehicle and Shipbuilding Sector:** Truck body frames, container skeletons, ship compartment frames. Impact-resistant and fatigue-resistant, meeting vehicle and ship manufacturing standards, and will not deform even after long-term vibrations.
**Direct supply from the steel mill, eliminating middlemen and their markups.** Exclusive discounts are available for bulk project orders. In-stock orders are loaded and shipped within 48 hours of order placement. Custom processing takes 3-7 days for delivery. Nationwide logistics delivery to construction sites/factories. Each batch of square and rectangular tubes comes with an original factory quality inspection report. Returns and exchanges are guaranteed for dimensional tolerances exceeding standards or materials failing to meet standards.
**Whether it's a large-scale infrastructure project involving thousands of tons or a small cutting need of a few meters, we can provide you with suitable specifications and competitive prices. For carbon steel square and rectangular tubes, choose us – one-time purchase for long-term peace of mind!**
WhatsApp：+86 133 5625 6103
