Seamless round tube VS Seamless square tube

Seamless steel pipes are widely used in many industries because of their no welds, high strength and strong pressure resistance. According to the different cross-sectional shapes, they can be mainly divided into seamless round pipes and seamless square pipes. The two differ in manufacturing process, physical properties and uses.Compared with solid steel such as round steel, steel pipe is lighter in weight when the bending and torsional strength are the same. It is an economical cross-section steel and is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames, and steel scaffolding used in construction. Using steel pipes to manufacture annular parts can improve material utilization, simplify manufacturing processes, save materials and processing time, such as rolling bearing rings and jack sleeves, which are currently widely made of steel pipes. Steel pipes are also an indispensable material for various conventional weapons. Gun barrels and cannon barrels are made of steel pipes. Steel pipes can be divided into round pipes and special-shaped pipes according to the shape of the cross-sectional area.

Since the area of a circle is the largest under the condition of equal circumference, more fluid can be transported using a round pipe. In addition, the circular cross-section is subjected to more uniform force when subjected to internal or external radial pressure. Therefore, most steel pipes are round pipes. However, round pipes also have certain limitations. For example, under the condition of plane bending, round pipes are not as strong in bending strength as square and rectangular pipes. Square and rectangular pipes are often used in some agricultural machinery frames, steel and wood furniture, etc. According to the mechanical properties of different square tubes.

Seamless round pipes are steel pipes with a hollow circular cross-section and no seams around. It is made of a whole piece of steel billet or ingot after perforation, and then processed by hot rolling, cold rolling or cold drawing. Because there are no welds, seamless round pipes have better pressure resistance, crack resistance and corrosion resistance, and are suitable for high temperature and high pressure environments, such as oil and gas transportation, machinery manufacturing, boiler pipelines, etc.

Seamless square pipes are seamless steel pipes with square or rectangular cross-sections. Their manufacturing process is similar to that of seamless round pipes, and they are usually formed by cold drawing or hot rolling of seamless round pipes. Seamless square tubes have better bending and torsion resistance and are widely used in building structures, machinery manufacturing and other fields. It can be further hot-dip galvanized or electro-galvanized to enhance corrosion resistance and extend service life.

Seamless round tubes are widely used in the following industries due to their excellent pressure bearing capacity, corrosion resistance and mechanical properties:

2.1 Oil and gas pipelines: Pipelines for the transportation of fluids such as oil, natural gas, coal gas, and water mostly use seamless round tubes, such as API 5L, ASTM A53 and other standard steel pipes.

2.2 Machinery manufacturing: Seamless round tubes are used to manufacture high-strength mechanical parts, such as automobile axles, drive shafts, bicycle frames, rolling bearing rings, etc.

2.3 Boilers and pressure vessels: Boiler tubes, heat exchanger tubes, pressure vessel tubes, etc. are all made of seamless round tubes, and common materials include ASTM A106, ASTM A335, etc.

2.5 Military and aerospace: High-precision parts such as gun barrels and cannon barrels are made of special alloy seamless steel pipes.

Seamless square tubes are mainly used in the following fields because of their stable structure and strong bearing capacity:

3.1 Construction industry: such as steel structures, color steel houses, bridge supports, etc. Common specifications include ASTM A500, GB/T 8162, etc.

3.2 Machinery manufacturing: motorcycle frames, electric vehicle main frames, agricultural machinery, etc. all use seamless square tubes.

3.3 Power engineering: used for wire conduits to ensure line stability.

Seamless round tubes and seamless square tubes have their own characteristics. The choice of which pipe material depends mainly on the specific purpose.

If used for high-pressure fluid transportation (oil, natural gas, water, etc.), seamless round tubes should be selected because they have better sealing and pressure resistance.

If used for building structures or mechanical support, seamless square tubes should be selected because they have stronger bending and torsion resistance, higher stability, and are more corrosion-resistant after galvanizing.