What is MS square tube?

What is MS Square Tube?

MS square tube, also known as mild steel square tube, is a hollow structural section (HSS) made of mild steel. It is one of the most widely used structural profiles in modern industry, its core advantage lying in achieving a perfect balance of strength, machinability, and reliability with an exceptional cost-performance ratio. Below, we will take a closer look at the material properties and applications of MS square tube.

Square Tube Material:

Square tubes are made of a wide variety of materials, and common materials include carbon steel, alloy steel, stainless steel, etc. Among them, carbon steel is the most commonly used material. According to different carbon content, it can be divided into ordinary carbon structural steel and high-quality carbon structural steel. Low carbon steel is an ordinary carbon structural steel with a carbon content generally between 0.05% and 0.25%. Square tubes can be divided into two types: seamless square tubes and welded square tubes according to the production process. According to different cross-sectional shapes, they can be divided into rectangular tubes and square tubes.

Characteristics of Low Carbon Steel:
Mild steel usually refers to carbon steel with a carbon content of less than 0.25%. It is also called mild steel because of its low strength, low hardness and softness. It includes most ordinary carbon structural steel and some high-quality carbon structural steel. Most of them are used for engineering structural parts without heat treatment, and some are used for mechanical parts requiring wear resistance after carburizing and other heat treatments.

The annealed structure of low carbon steel is ferrite and a small amount of pearlite, which has lower strength and hardness and better plasticity and toughness. Therefore, it has good cold formability and can be cold formed by curling, bending, stamping and other methods. In addition, this steel has good weldability.

Characteristics of MS Square Tube:
1. Material: MS square tube is made of mild steel, a type of mild steel known for its durability and strength.
2. Shape: As the name suggests, MS square tube has a square cross-section. They are available in various sizes and thicknesses to meet different requirements.
3. Hollow structure: MS square tube is hollow inside, making it light in weight while maintaining structural strength. This design helps reduce the overall weight of the structure.
4. Low cost: Compared with other steel materials, low carbon steel is relatively cheap, and its lower carbon content can also reduce environmental pollution.
5. Weldable: Mild steel is easy to weld, allowing the use of MS square tubes to manufacture various structures and frames.

6. Mechanical properties: It has good plasticity and toughness, can be manufactured into various shapes, and has high strength and hardness.

Three Core Advantages of MS Square Tube:

1. Ultimate cost-effectiveness
While meeting the vast majority of structural performance requirements, it boasts the lowest cost per unit load-bearing capacity.

Low Raw Material Costs: Primarily composed of iron and carbon, with abundant reserves and mature smelting processes.
High Production Efficiency: Mainly employing cold bending high-frequency welding (ERW) technology, enabling continuous high-speed production and high material utilization.

2. Excellent comprehensive machinability

Excellent Weldability: Its low carbon content allows for the use of all conventional welding methods (arc welding, gas shielded welding, etc.) without the need for complex preheating and post-weld treatment, facilitating on-site construction and connection.
Excellent cold-working performance: Easy to cut, drill, and cold-bend, flexibly adaptable to various design shapes and connection requirements.
Strong surface treatment compatibility: Can be easily hot-dip galvanized, painted, powder-coated, etc., to meet different corrosion resistance and aesthetic requirements.

3. Reliable and balanced mechanical properties
Sufficient strength: Typical grades such as S235JR (yield strength 235MPa) and S355J2H (yield strength 355MPa) have sufficient strength to meet the load requirements of most structures, from furniture to ordinary factories and bridges.
Good plasticity and toughness: Provides early warning before significant deformation occurs, avoiding brittle fracture and ensuring high safety.

Uses of MS Square Tube:
1. Construction: Due to its strength and load-bearing capacity, MS square tubes are often used in construction projects for building frames, supports and columns.
2. Fences: They are used in fencing applications to provide a strong and secure perimeter to a property.
3. Automotive: In some cases, MS square tubes are used in the automotive industry to manufacture components such as roll cages and chassis components.
4. Industrial Machinery: These pipes are also used in the manufacturing of industrial machinery and equipment.

5. Furniture: MS square tubes are used to make furniture frames such as tables, chairs and shelves due to their durability and versatility.

MS Welded Square Tubes vs MS Seamless Square Tubes:

MS square tubes can be divided into MS Welded (ERW) square tubes and MS Seamless square tubes based on their production process.

MS Welded Square Tubes:
Made by bending steel plates or strips into shape and then welding them, they have weld seams, offer high production efficiency, and are relatively low in cost. Welded square tubes may have stress concentrations in their weld seams, resulting in slightly lower strength than seamless tubes. ERW square tubes are the most commonly used.

MS Seamless Square Tubes:
Made by piercing, rolling, or cold drawing round steel billets, they have no weld seams and offer better overall performance, but at a higher cost. Seamless square tubes are divided into hot-rolled square tubes and cold-drawn (rolled) square tubes based on their production process.

1. Hot-Rolled Seamless Square Tubes:
Heat-rolled steel billets are rolled into shape, resulting in thicker walls. They are suitable for load-bearing structures and mechanical components.

2. Cold-Drawn (Cold-Rolled) Seamless Square Tubes:
Drawn or rolled through dies at room temperature, they offer high dimensional accuracy and a smooth surface. They are suitable for precision machinery, hydraulic systems, and other applications.

Cold-Formed Square Tube:
Strip steel is directly rolled into a square shape through a cold-formed process, then welded or seamlessly finished. Suitable for thin-walled, lightweight structures such as shelves, decorative tubes, and door and window frames.

Application Status:

In the spectrum of structural materials, MS square tubing is at the golden balance point of performance and cost:

1) Compared with higher-end materials (such as stainless steel and aluminum alloys): 

MS square tubing is inferior in absolute corrosion resistance or lightweight, but its cost is only 1/3 to 1/2 of theirs, thus possessing an overwhelming economic advantage in structures in non-extreme environments.

2) Compared to more traditional materials (such as wood and concrete): 

MS square tubing offers a higher strength-to-weight ratio, faster construction speed, more precise dimensions, and recyclability.

3) Compared to other steel sections (such as I-beams and angle steel): 

As a closed section, MS square tubing exhibits excellent bending and torsional resistance in both principal axis directions. Its neat appearance and easy connection make it an ideal choice for constructing frames and trusses.

Read more: Manufacturing Process of MS Square Tube or Square Tube Size