Square Tube Wall Thickness

Square tube (SHS steel) is one of the most commonly used metal profiles in structural engineering, manufacturing, machinery, and architectural decoration. The wall thickness of square tube is a core parameter affecting its strength, stability, weight, cost, and service life.

Basics of Square Tube Wall Thickness

The wall thickness of a square tube refers to the thickness of the metal material in its cross-section, usually measured in millimeters.

Accurate wall thickness measurement is crucial as it affects the overall strength and weight of the square tube.

For example, with the same cross-sectional dimensions, a thicker wall thickness allows a square tube to withstand higher loads, but also increases material cost and weight. Conversely, a thinner wall thickness makes it lighter and suitable for weight-sensitive applications, but may be less effective in certain high-strength scenarios.

Methods of Expressing Square Tube Wall Thickness

1. Metric Method

This method uses millimeters as the unit, directly reflecting the actual wall thickness of the square tube.

For example, a square tube with dimensions of 20 x 20 mm and a wall thickness of 2 mm can be simply expressed as 20 x 20 x 2.0.

2. Imperial Units Expression Method

This method converts the square tube wall thickness to inches, which is more intuitive for users accustomed to imperial units.

If the square tube wall thickness is given in millimeters, it must first be converted to inches.

For example, a wall thickness of 20mm corresponds to 0.7874 inches. Therefore, a square tube with dimensions of 2 x 2 inches and a wall thickness of 20mm can be expressed as 2 x 2 x 0.7874.

3. Cross-sectional Area Weight Expression Method

This method expresses the wall thickness by calculating the weight per meter of the square tube. It is commonly used for cost estimation and logistics weight distribution.

The calculation formula combines the cross-sectional area and the weight per unit length. For example, the cross-sectional area weight of a square tube with dimensions of 50 x 50mm and a wall thickness of 4.5mm can be obtained using a specific formula.

Square Tube Dimensions

Wall Thickness Range of Square Tubes of Different Sizes

1. Small Square Tubes (13–50mm)

Common Wall Thickness: 0.8–3.0mm

Uses: Furniture, Shelving, Decorative Structures.

2. Medium Square Tubes (50–100mm)

Common Wall Thickness: 2.0–6.0mm

Uses: Building Railings, Machinery Frames.

3. Large Square Tubes (100–200mm)

Common Wall Thickness: 4.0–20mm

Uses: Columns, Heavy Structures, Equipment Supports.

Wall Thickness Range of Square Tubes by Different Processes

1. Hot-Dip Galvanized Square Tubes

The wall thickness of hot-dip galvanized square tubes is typically between 0.8-6.0mm.

Common specifications include 20 x 20 x 0.8mm, 40 x 40 x 1.5mm, etc.

2. Welded Square Tubes

Welded square tubes have a wider wall thickness range, generally from 0.6mm to 20mm.

Due to its excellent load-bearing capacity and weldability, it is widely used in construction, bridges, and other fields.

3. Seamless Square Tubes

Seamless square tubes typically have a wall thickness between 1.0-12mm and possess high precision and mechanical properties.

They are commonly used in high-precision machinery manufacturing and hydraulic equipment.

Square Tube Wall Thickness in mm

Comparison of Square Tube Wall Thickness with Other Tube Materials

1. Square Tube vs. Round Tube

Compared to round tubes (CHS steel), square tubes have unique advantages in wall thickness design.

Round tubes typically have a uniform wall thickness distribution, but square tubes are easier to optimize in terms of bending and torsional resistance due to their cross-sectional shape.

For example, in building structures, by adjusting the wall thickness of square tubes, overall stability can be improved without increasing weight.

Round tubes may require thicker walls in some situations to achieve the same effect, leading to material waste and increased costs.

2. Square Tube vs. Rectangular Tube

Compared to rectangular tubes (RHS steel), square tubes have more standardized wall thickness design.

Rectangular tubes may be affected by the uniformity of their aspect ratio and wall thickness, while square tubes, with equal sides, have a more uniform wall thickness distribution, making the manufacturing process easier to control.

This gives square tubes the advantage of high consistency in mass production.

The Impact of Wall Thickness on Square Tube Performance

1. Bending Strength

The greater the wall thickness, the stronger the bending resistance. Suitable for: equipment racks, bridge structures, heavy-duty frames.

2. Compressive Strength

Thick-walled square tubes are less prone to buckling and are suitable for columns, purlins, and floor supports.

3. Torsional Strength

Due to their symmetrical cross-section, square tubes have strong torsional resistance. The greater the wall thickness, the more stable the torsional resistance.

4. Corrosion Resistance

Thin-walled square tubes are more susceptible to corrosion. Recommendation: Increase wall thickness and choose galvanized steel.

Factors Affecting Square Tube Wall Thickness

1. Operating Environment

In highly corrosive environments or environments requiring heavy loads, thicker steel tubes are needed to ensure safety.

2. Manufacturing Process

Different manufacturing processes affect the wall thickness of the steel tube. For example, hot-rolled steel tubes typically have thicker walls than cold-rolled tubes.

3. Tube Diameter

As the tube diameter increases, the wall thickness needs to be increased accordingly to ensure sufficient strength and rigidity.

How to Choose the Appropriate Square Tube Wall Thickness

1. Load Requirements

Select an appropriate thickness based on the required load-bearing capacity. Generally, thicker steel pipes are required for applications with high load-bearing requirements.

2. Operating Environment

When used in corrosive environments, thick-walled steel pipes with better corrosion protection should be selected.

3. Economy

While ensuring safety, the lowest possible steel pipe thickness should be chosen to improve economic efficiency.

FAQ

1. Is Thicker Wall Thickness Always Better for Square Tubes?

Not necessarily.

Thicker wall thickness generally means higher strength, but also significantly increased cost and weight.

The appropriate wall thickness should be selected based on the load, application, and structural design, rather than simply increasing thickness indiscriminately.

2. Are Thin-Walled Square Tubes Prone to Deformation?

Yes.

Thin-walled square tubes (≤1.5mm) are more prone to deformation under welding, bending, or external forces.

They are suitable for light loads and decorative applications, but not for heavy load scenarios.

Summary

The wall thickness of square tubes is a key parameter that not only determines the basic performance of the pipe but also affects the economy and feasibility of practical applications. By rationally selecting the wall thickness, square tubes can play an important role in diverse scenarios. Compared to other pipe materials, the flexibility and standardization of square tube in wall thickness design make it the preferred choice in many fields.

Read more: What is the difference between square tube and rectangular tube? or SHS steel meaning