Square Tubes Size – Carbon Steel Square Tube(4×4/ 3×3)

erw carbon steel pipe

Square tube has become the preferred manufacturing material for manufacturers, because of its unique shape and excellent performance. Its widely welcomed factors are various, including but not limited to structural stability, ease of processing, cost, and efficiency, and its wide application in many fields.

Square Tube Structure and Characteristics

The cross-section design of the square steel pipe lays a solid foundation for its durability. The two sides of the rectangular steel pipe are the same size and the force distribution is very uniform, which means that it can show excellent performance in a variety of pressure, tensile forces and impact situations.

The more commonly used square tube specifications are: 1 inch/ 2 inch steel square tube/ 3×3/ 4×4 steel square tube/ 1.5 square tube steel. These sizes of square tubing have good stress capacity and are more cost effective!

This unique design allows square steel pipes to demonstrate their superior performance in environments facing high loads and complex stress demands.

To understand the force capacity of square tubes, see the table below.

What Is Square Tube

Square steel pipe is a kind of tubular material produced by welding process. This kind of pipe belongs to structural grade. It can be classified as either the A513 or the A500 B class. The various types of steel pipes are determined by their specific dimensions and the thickness of the pipe wall. Regardless of the grade of steel pipe, they have a variety of different functions.

TUSPIPE can provide standard length and custom cut dimensions of carbon fiber square tubes, such as square hollow section steel pipes.

Standard: ASTM A500, EN10219, EN10296.

Grade: GR. A, GR. B, GR. C, Q195, Q235B, Q345B.

Square Tube Applications

The application range of square steel pipe is also quite wide. Manufacturers prefer it because it can be easily cut and welded into new applications.

Due to a variety of factors, the square tube form is considered the best choice. It provides stability not available in a grooved or inclined pipe. And it’s much stronger than a groove or a corner tube.

Square tubes are mainly used in the following fields:

  • Tow lathe/trailer parts
  • Industrial equipment
  • Machine parts
  • Sign pole
  • Agricultural equipment
  • Electrical appliances
  • Buildings
  • Furniture
  • Structural engineering
  • Car chassis
  • Conveyor

Mechanical Properties of Galvanized Square Tube

The durability of the square steel pipe benefits from the careful process of its surface treatment. Through a variety of technologies such as galvanizing and spraying, the surface is carefully processed, and these treatments significantly enhance the resistance of the steel pipe to corrosion and oxidation, thus ensuring the durability of the steel pipe and effectively extending its service life.

square tube

Galvanized Steel Square Tube Process

Galvanized square tube, that is, steel pipe made of hot rolled steel or low carbon steel as raw materials, is surface treated by a specific melt galvanizing process.

A distinguishing mark of this galvanizing process is the unique crystalline pattern formed on its surface, often graphically referred to as “glitter”. Because of its excellent corrosion resistance, galvanized square pipes are especially suitable for applications outdoors or exposed to a variety of environmental conditions.

2x2 & 4x4 Square Tube Strength and Others

A 2×2 square tube with a wall thickness of 0.1875 inches can carry 4.32 pounds per foot length.
A 4×4 square tube with 0.25 inches of wall thickness can carry 5.41 pounds per foot length.

Therefore, pipe size is proportional to wall thickness and bearing capacity.

Mechanical Properties Tensile Strength and Yield Strength of Square Hollow Section as shown below:


Grade A

Grade B

Grade C

Grade D

Tensile strength, min, psi (MPa)

45000 (310)

58000 (400)

6200 (427)

58000 (400)

Yield strength, min, psi (MPa)

39000 (269)

46000 (317)

50000 (345)

36000 (250)

Elongation in 2 in. (50.8 mm), min, %A





Square Tube Factory- Square Steel Tube(1/ 2/ 3/ 4inch)

With excellent structural strength, convenient processing characteristics and a wide range of applications, square steel pipes have become the preferred material in many industries.

With the increasing progress of science and technology and the continuous expansion of the market, the development prospects of square steel pipes will undoubtedly be more bright and broad.


  1. How is a square tube different from a rectangular tube?

It varies in strength and durability.
Under normal circumstances, the bearing capacity and bending strength of rectangular tubes are higher than that of square tubes, and the torsion resistance of square tubes is stronger.

2. Is square tubing measured inside or outside?

Square tubing is measured by external dimensions and wall thickness and has an inside seam.

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  1. Over 25 years of experience in pipeline production and installation.
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  5. Complete qualifications – API 5L/API 5CT/FM/UL fire pipe certification, etc.
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