Carbon steel square tubes, also known as Square Hollow Sections (SHS), are available in a wide range of sizes, wall thicknesses, and material grades for structural and mechanical applications.
The most common square tube sizes range from 20 × 20 mm to 500 × 500 mm (metric) and 1/2 × 1/2 in to 16 × 16 in (imperial). Wall thicknesses typically vary from 0.5 mm to 25 mm, depending on the manufacturing standard and intended application. Whether you're an engineer, contractor, fabricator, or purchasing manager, this guide provides a quick reference for selecting the correct carbon steel square tubing.
What Is a Carbon Steel Square Tube?
A carbon steel square tube is a hollow structural steel section (SHS) with four equal sides. Unlike round steel pipe, square tubing is identified by its outside dimensions (A × A) and wall thickness, making specification and structural design more straightforward.
|
Size (in)
|
Wall Thickness (in)
|
Weight (lbs/ft)
|
Standard Length (ft)
|
|
1/2 × 1/2
|
0.063
|
0.38
|
20 / 24
|
|
3/4 × 3/4
|
0.063
|
0.61
|
20 / 24
|
|
1 × 1
|
0.063
|
0.83
|
20 / 24
|
|
1 × 1
|
0.125
|
1.35
|
20 / 24
|
|
1 1/2 × 1 1/2
|
0.063
|
1.27
|
20 / 24
|
|
1 1/2 × 1 1/2
|
0.125
|
2.21
|
20 / 24
|
|
1 1/2 × 1 1/2
|
0.188
|
3.05
|
20 / 24
|
|
1 1/2 × 1 1/2
|
0.250
|
4.42
|
20 / 24
|
|
2 × 2
|
0.063
|
1.69
|
20 / 24 / 40
|
|
2 × 2
|
0.125
|
3.06
|
20 / 24 / 40
|
|
2 × 2
|
0.188
|
4.33
|
20 / 24 / 40
|
|
2 × 2
|
0.250
|
5.41
|
20 / 24 / 40
|
|
3 × 3
|
0.125
|
4.76
|
20 / 24 / 40
|
|
3 × 3
|
0.188
|
6.89
|
20 / 24 / 40
|
|
3 × 3
|
0.250
|
8.81
|
20 / 24 / 40
|
|
3 × 3
|
0.375
|
12.17
|
20 / 24 / 40
|
|
4 × 4
|
0.125
|
6.46
|
20 / 24 / 40 / 48
|
|
4 × 4
|
0.188
|
9.45
|
20 / 24 / 40 / 48
|
|
4 × 4
|
0.250
|
12.21
|
20 / 24 / 40 / 48
|
|
4 × 4
|
0.375
|
17.27
|
20 / 24 / 40 / 48
|
|
4 × 4
|
0.500
|
21.63
|
20 / 24 / 40 / 48
|
|
6 × 6
|
0.188
|
14.56
|
20 / 24 / 40 / 48
|
|
6 × 6
|
0.250
|
19.02
|
20 / 24 / 40 / 48
|
|
6 × 6
|
0.375
|
27.48
|
20 / 24 / 40 / 48
|
|
6 × 6
|
0.500
|
35.24
|
20 / 24 / 40 / 48
|
|
8 × 8
|
0.250
|
25.82
|
20 to 48
|
|
8 × 8
|
0.375
|
37.69
|
20 to 48
|
|
8 × 8
|
0.500
|
48.45
|
20 to 48
|
|
10 × 10
|
0.250
|
32.60
|
20 to 48
|
|
10 × 10
|
0.375
|
47.90
|
20 to 48
|
|
10 × 10
|
0.500
|
62.20
|
20 to 48
|
|
12 × 12
|
0.250
|
39.43
|
20 to 48
|
|
12 × 12
|
0.500
|
76.07
|
20 to 48
|
|
12 × 12
|
0.625
|
93.34
|
20 to 48
|
|
16 × 16
|
0.375
|
78.52
|
Up to 60
|
|
16 × 16
|
0.500
|
103.30
|
Up to 60
|
|
16 × 16
|
0.625
|
127.36
|
Up to 60
|
Metric Carbon Steel Square Tube Sizes (EN 10219 / GB/T 6728)
|
Size (mm)
|
Wall Thickness (mm)
|
Weight (kg/m)
|
Standard Length (m)
|
|
20 × 20
|
2.0
|
1.05
|
6
|
|
20 × 20
|
2.5
|
1.25
|
6
|
|
25 × 25
|
2.0
|
1.36
|
6
|
|
25 × 25
|
3.0
|
1.89
|
6
|
|
30 × 30
|
2.0
|
1.68
|
6
|
|
30 × 30
|
3.0
|
2.40
|
6
|
|
40 × 40
|
2.0
|
2.30
|
6 / 8
|
|
40 × 40
|
3.0
|
3.30
|
6 / 8
|
|
40 × 40
|
4.0
|
4.20
|
6 / 8
|
|
50 × 50
|
2.0
|
2.90
|
6 / 8
|
|
50 × 50
|
3.0
|
4.30
|
6 / 8
|
|
50 × 50
|
4.0
|
5.50
|
6 / 8
|
|
50 × 50
|
5.0
|
6.60
|
6 / 8
|
|
60 × 60
|
3.0
|
5.20
|
6 / 8
|
|
60 × 60
|
4.0
|
6.70
|
6 / 8
|
|
60 × 60
|
5.0
|
8.10
|
6 / 8
|
|
60 × 60
|
6.0
|
9.50
|
6 / 8
|
|
75 × 75
|
3.0
|
6.64
|
6 / 8 / 12
|
|
75 × 75
|
5.0
|
10.51
|
6 / 8 / 12
|
|
80 × 80
|
4.0
|
9.20
|
6 / 8 / 12
|
|
80 × 80
|
6.0
|
13.20
|
6 / 8 / 12
|
|
100 × 100
|
3.0
|
9.00
|
6 / 8 / 12
|
|
100 × 100
|
5.0
|
14.40
|
6 / 8 / 12
|
|
100 × 100
|
6.0
|
17.00
|
6 / 8 / 12
|
|
100 × 100
|
8.0
|
21.40
|
6 / 8 / 12
|
|
120 × 120
|
4.0
|
14.10
|
8 / 12
|
|
120 × 120
|
6.0
|
20.70
|
8 / 12
|
|
150 × 150
|
5.0
|
22.60
|
8 / 12
|
|
150 × 150
|
6.0
|
26.46
|
8 / 12
|
|
150 × 150
|
8.0
|
34.62
|
8 / 12
|
|
150 × 150
|
10.0
|
42.33
|
8 / 12
|
|
200 × 200
|
6.0
|
35.88
|
12 / 15
|
|
200 × 200
|
10.0
|
58.03
|
12 / 15
|
|
200 × 200
|
12.5
|
71.07
|
12 / 15
|
|
250 × 250
|
8.0
|
60.30
|
12 / 15
|
|
250 × 250
|
12.5
|
91.90
|
12 / 15
|
|
300 × 300
|
10.0
|
90.20
|
12 / 15
|
|
300 × 300
|
12.5
|
110.31
|
12 / 15
|
|
300 × 300
|
16.0
|
138.96
|
12 / 15
|
|
400 × 400
|
12.5
|
151.00
|
12 to 18
|
|
400 × 400
|
16.0
|
189.00
|
12 to 18
|
|
500 × 500
|
12.5
|
189.00
|
12 to 18
|
Recommended Square Tube Sizes by Application
|
Application
|
Recommended Size Range
|
Typical Wall Thickness
|
Notes
|
|
Furniture & Decorative Frames
|
20×20 – 40×40 mm
|
1.0 – 2.0 mm
|
Lightweight, aesthetic finish preferred.
|
|
Handrails, Fences & Guardrails
|
30×30 – 50×50 mm
|
1.5 – 3.0 mm
|
Requires good weldability and surface finish.
|
|
Light Machinery Frames & Supports
|
50×50 – 100×100 mm
|
3.0 – 6.0 mm
|
Moderate strength needed; good balance of weight and rigidity.
|
|
Structural Columns & Heavy Equipment Frames
|
100×100 – 200×200 mm
|
4.0 – 10.0 mm
|
High strength; design should comply with structural codes (e.g., AISC).
|
|
Heavy Civil Structures & Bridges
|
≥200×200 mm
|
≥8.0 mm
|
Load-bearing design required; consult structural engineer.
|
Dimensional Tolerances (ASTM A500 vs. EN 10219)
|
Item
|
ASTM A500
|
EN 10219
|
|
Outside Dimensions
|
±1% (or ±0.020", whichever is greater)
|
±1%
|
|
Wall Thickness
|
±10%
|
±10%
|
|
Straightness
|
1/8 in per 5 ft
|
0.2% of total length
|
|
Squareness (Corners)
|
90° ± 1.5°
|
90° ± 1.5°
|
|
Mass Tolerance
|
-3.5%
|
-3.5%
|
Square Tube Dimensions by Standard
|
Standard System
|
Standards
|
Size Range
|
Typical Applications
|
|
American (ASTM)
|
ASTM A500 (Cold-formed), ASTM A501 (Hot-formed)
|
1/2" × 1/2" to 32" × 32" (custom sizes up to 800mm)
|
Structures, bridges, general fabrication in North America
|
|
European (EN)
|
EN 10219 (Cold-formed), EN 10210 (Hot-finished)
|
20×20 mm to 500×500 mm
|
Structural and mechanical applications in Europe & international projects
|
|
Chinese (GB/T)
|
GB/T 6728, GB/T 3094
|
20×20 mm to 600×600 mm
|
Building structures, machinery, chemical equipment in China
|
|
Japanese (JIS)
|
JIS G 3466
|
20×20 mm to 400×400 mm
|
Structural uses in Japan and Asian markets
|
|
Australian (AS/NZS)
|
AS/NZS 1163
|
Similar to EN range
|
Structural applications in Australia & New Zealand
|
How to Choose the Right Carbon Steel Square Tube Size
When selecting a square tube, engineers generally consider five key factors:
|
Factor
|
Recommendation
|
|
Load Capacity
|
Larger dimensions and thicker walls support heavier loads.
|
|
Application
|
Decorative frames require thinner walls, while structural columns need heavier sections.
|
|
Manufacturing Standard
|
ASTM A500, EN 10219, GB/T 6728, or JIS G3466 depending on project location.
|
|
Material Grade
|
Q235, Q355, ASTM A36, ASTM A500 Grade B/C, S355.
|
|
Corrosion Protection
|
Black, galvanized, painted, or pickled finishes according to the service environment.
|
Conclusion
Carbon steel square tubes are available in a comprehensive range of dimensions, wall thicknesses, material grades, and manufacturing standards to meet structural and mechanical engineering requirements. By comparing size charts, theoretical weights, tolerances, material specifications, and application recommendations, engineers and buyers can quickly identify the most suitable square tubing for their projects. This guide serves as a practical reference for selecting carbon steel square tubes across construction, infrastructure, machinery, transportation, and industrial fabrication applications.
FAQ
- What is the most common carbon steel square tube size?
The most commonly used structural sizes are 40 × 40 mm, 50 × 50 mm, 100 × 100 mm, and 2 × 2 in, 4 × 4 in under ASTM A500 specifications. Selection depends on structural load and application.
- What wall thickness is available for square tubing?
Carbon steel square tubing is typically available from 0.5 mm to 25 mm wall thickness, although availability varies by size and manufacturing standard.
- What standards cover carbon steel square tubes?
The most widely used standards include:
ASTM A500
ASTM A501
EN 10219
EN 10210
GB/T 6728
JIS G3466
- How do I calculate square tube weight?
The theoretical weight is calculated using the outside dimension, wall thickness, and carbon steel density. Standard weight charts provide quick references, while custom dimensions require calculation using the standard formula.
English
Español
