High-quality seamless steel pipe is a hollow section, the surrounding no seam of the long steel. The steel pipe has a hollow section, a large number of pipes used to transport fluid, such as the transmission of oil, natural gas, gas, water and some solid materials such as pipeline. Steel and round steel and other solid steel compared to the same bending strength, the weight is light, is an economic section of steel, widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, car drive shaft, bicycle Racks and steel scaffolds for construction purposes. The use of steel pipe manufacturing ring parts, can improve the utilization of materials, simplify the manufacturing process, saving materials and processing time, such as rolling bearing rings, jack sets, etc., has been widely used to manufacture steel. Steel pipe or a variety of conventional weapons indispensable materials, barrels, barrels and so on to steel to manufacture. Steel pipe by cross-sectional area of ​​the shape can be divided into tube and shaped tube. As the circumference of the same conditions, the largest circular area, with a circular tube can transport more fluid. In addition, the ring cross section in the internal or external radial pressure, the force is more uniform, so the vast majority of steel pipe is a tube.

However, the tube also has some limitations, such as in the plane under the conditions of bending, the tube is not as good as the square tube bending strength, some agricultural machinery skeleton, steel and wood furniture on the commonly used side, rectangular tube. According to different purposes also need to have other cross-shaped shaped steel pipe.