Seamless pipe meaning: seamless steel pipe is perforated from a whole round steel, and there is no weld on the surface of the steel pipe, so it is called seamless steel pipe.

1. According to the production method, seamless steel tubes can be divided into hot-rolled seamless steel tubes, cold-rolled seamless steel tubes, cold-drawn seamless steel tubes, and extruded seamless steel tubes.
2. According to the cross-sectional shape, seamless steel pipes are divided into two types: round and special-shaped. Special-shaped pipes have square, oval, triangular, hexagonal, melon seed, star, and finned pipes. The maximum diameter is 900mm and the minimum diameter is 4mm.
3. According to different purposes, there are thick-walled seamless steel pipes and thin-walled seamless steel pipes.

API 5CT Seamless Steel Oil Pipeline

Seamless steel pipes have a hollow section and are used in large quantities as pipelines for conveying fluids, such as pipelines for conveying oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, steel pipe has a lighter weight when the bending and torsion strength is the same, and it is a kind of economical cross-section steel. It 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.

 

The use of steel pipes to manufacture ring-shaped parts can increase the utilization rate of materials, simplify the manufacturing process, save materials and processing man-hours, such as rolling bearing rings, jack sleeves, etc., which have been widely used for manufacturing steel pipes. Steel pipes are also an indispensable material for various conventional weapons. Gun barrels and barrels are all made of steel pipes. Steel pipes can be divided into round pipes and special-shaped pipes according to different cross-sectional area shapes. Since the circle area is the largest under the condition of the same circumference, more fluid can be transported with a circular tube. In addition, when the ring section is subjected to internal or external radial pressure, the force is relatively uniform. 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 as square and rectangular pipes. Some agricultural machinery frameworks, steel and wood furniture, etc. often use square and rectangular pipes. According to different purposes, special-shaped steel pipes with other cross-sectional shapes are required.

According to the different shape and size of the steel pipe section, it can be divided into equal wall thickness special-shaped seamless steel pipe (code D), unequal wall thickness special-shaped seamless steel pipe (code BD), and variable diameter special-shaped seamless steel pipe (code BJ). Special-shaped seamless steel pipes are widely used in various structural parts, tools and mechanical parts. Compared with round pipes, special-shaped pipes generally have larger moments of inertia and section modulus, and have greater bending and torsion resistance, which can greatly reduce structural weight and save steel.