How to select square tubes and rectangular tubes？

Square tubes (SHS steel) and rectangular tubes (RHS steel) are collectively referred to as Hollow Structural Sections (HSS).

They are typically manufactured from hot-rolled or cold-rolled strip steel through processes such as uncoiling, flattening, rolling, welding, shaping, and cutting to length.

They can also be obtained through secondary forming of hot-rolled seamless steel pipes. Due to their different cross-sectional shapes, they differ significantly in strength distribution, load-bearing capacity, applications, and costs.

Square Tube Meaning

1. Material Structure of Square Tubes

Square tubes have a square cross-section with four equilateral right angles.

2. Manufacturing Process of Square Tubes

Square tubes can be manufactured using various processes such as hot rolling, cold rolling, cold drawing, or hot-dip galvanizing, offering advantages such as low production costs and high production efficiency.

3. Square Tube Sizes

Common sizes: 10×10mm, 20×20mm, 25×25mm, 40×40mm, 50×50mm, 100×100mm, 150×150mm

Wall thickness range: 0.6mm – 6.0mm

Length: Standard length 6m (customizable up to 12m).

4. Load-Bearing Capacity of Square Tubes

Square tubes are superior in withstanding bending loads and can withstand greater bending forces.

5. Applications of Square Tubes

Square tubes are widely used in petroleum, chemical, power, and automotive industries, such as in automobile frames and petrochemical oil pipelines.

Rectangular Tube Meaning

1. Material Structure of Rectangular Tubes

Rectangular tubes have a rectangular cross-section with four right angles.

2. Manufacturing Process of Rectangular Tubes

Rectangular tubes are generally manufactured using hot rolling or cold rolling processes, resulting in relatively high production costs.

3. Rectangular Tube Sizes

Common sizes: 20×30mm, 25×50mm, 40×80mm, 50×100mm, 80×120mm, 100×200mm

Wall thickness range: 0.8mm – 8.0mm

Length: Standard 6m, custom lengths available upon request.

4. Load-Bearing Capacity of Rectangular Tubes

Rectangular tubes have higher strength than square tubes for the same cross-sectional area.

5. Applications of Rectangular Tubes

Rectangular tubes are commonly used in construction, machinery manufacturing, and other fields, such as steel frame structures and corridor railings.

Square Tubes vs. Rectangular Tubes: How to Choose

1. Choose Based on the Direction of Force

Choose square tubes (SHS steel):

When a structure needs to withstand bending, torsion, or lateral forces from multiple directions (e.g., columns, support frames, vehicle frames, machinery frames).

Square tubes, due to its symmetrical cross-section, exhibits consistent strength in all directions, making it better able to resist multi-directional stresses and torques.

Typical applications: automotive chassis, towers, machinery frames, railings, equipment supports.

Choose rectangular tubes (RHS steel):

When the direction of force is clear (e.g., vertical compression or horizontal bending), rectangular tubes has stronger bending resistance along its long side, allowing it to withstand greater loads with the same material usage.

Typical applications: Building beams and columns, portal frames, corridor structures, warehouse racking.

2. Selection Based on Structural Design and Space Dimensions

Select square tubes (SHS steel):

When space is limited and a square and symmetrical shape is required.

Square tubes has a compact cross-section, suitable for columns, square frames, decorative structures, etc.

It also has a more harmonious appearance and is often used in building facades, furniture, landscape railings, and other applications requiring aesthetic appeal.

Select rectangular tubes (RHS steel):

For larger spans, material usage needs to be optimized.

Rectangular tubes can more efficiently distribute the moment of inertia of the material in the main force direction, reducing weight and cost in beams, support arms, and frame beams.

3. Economic and Cost Considerations

Rectangular tubes offer superior structural efficiency and lower costs. Square tubes offer advantages in symmetrical stress distribution and aesthetic harmony.

4. Connection and Welding Requirements

Square tubes are easier to align during welding, making them suitable for square nodes and symmetrical connection structures.

Rectangular tubes require careful attention to weld design and stress symmetry along their long and short sides during connection.

For complex node stresses or situations with limited weld space, square tubes are generally easier to install.

5. Quality Certification

When purchasing, ensure that the square tubes meet relevant standards and quality certification requirements to guarantee their reliability.

6. Price Comparison

In addition to the above factors, you should compare the prices of square and rectangular tubes from different suppliers or brands and make a final choice based on cost-effectiveness.

How to Identify Inferior Square Tube and Rectangular Tubes?

1. Observe Creases and Ripples

High-quality tubes have a smooth surface, while inferior products are prone to wrinkles or creases.

2. Check Weld Quality

Welds should be uniform and free of porosity. Inferior pipes often exhibit weld cracks or incomplete penetration.

3. Touch and Gloss

High-quality pipes have a smooth surface and a metallic luster; inferior pipes appear reddish or dull.

4. Measuring Wall Thickness

Use calipers to measure whether the wall thickness matches the nominal thickness. Inferior products often misrepresent their thickness.

5. Brand and Certification

Choose reputable manufacturers with ISO certification and factory inspection reports.

FAQ

1. SHS Steel vs. RHS Steel: Which is Cheaper?

Prices may vary depending on:

Size and wall thickness

Steel grade and coating (galvanized or raw steel)

Cutting and processing requirements

Generally, rectangular steel pipes (RHS) may be slightly cheaper per meter, especially for larger spans, as it achieves the required strength with less material. However, square steel pipes (SHS) are generally more common in general-purpose construction.

2. Are Rectangular Tubes Recyclable?

Yes, rectangular tubes are recyclable. 

It is typically made of carbon steel, stainless steel, or aluminum, all of which are 100% recyclable and can be used to manufacture new metal products, making it both environmentally friendly and energy-efficient.

Summary

In summary, when choosing between square tubs (SHS) and rectangular tubs (RHS), the direction of force, load-bearing requirements, appearance requirements, and cost factors should be considered comprehensively: if multi-directional load-bearing performance and aesthetic harmony are desired, choose square tubs; if high bending resistance and material efficiency are desired, choose rectangular tubs.

Read more: SHS Steel vs. CHS Steel: Which is Stronger?