Seamless steel pipe is a long strip of steel with a hollow cross-section and no seams around it. Steel pipes have a hollow cross-section and are widely used as pipelines for transporting fluids, such as oil, natural gas, gas, water, and certain solid materials. Compared with solid steel such as round steel, steel pipes have a lighter weight when their bending and torsional strength are the same. They are an economical cross-section steel and are widely used in the manufacturing of structural and mechanical components, such as petroleum drill pipes, automotive transmission shafts, bicycle frames, and steel scaffolding used in construction.
Manufacturing circular parts using steel pipes can improve material utilization, simplify manufacturing processes, save materials and processing time, such as rolling bearing rings, jack sleeves, etc. Steel pipes are widely used for manufacturing. Steel pipes are also an indispensable material for various conventional weapons, and they are used to manufacture gun barrels and barrels. Steel pipes can be divided into circular pipes and irregular pipes according to their cross-sectional area and shape.
Due to the fact that under the condition of equal circumference, the circular area is the largest, and circular pipes can transport more fluid. In addition, when the circular ring section is subjected to internal or external radial pressure, the force is relatively uniform, therefore, the vast majority of steel pipes are circular pipes. However, circular pipes also have certain limitations. For example, under the condition of plane bending, circular pipes are not as strong as square and rectangular pipes in terms of bending strength. Some agricultural machinery skeletons, steel and wood furniture, etc. are commonly used in square and rectangular pipes.
Classification:
According to the different cross-sectional dimensions of steel pipes, they can be divided into equal wall thickness irregular seamless steel pipes (code D), unequal wall thickness irregular seamless steel pipes (code BD), and variable diameter irregular seamless steel pipes (code BJ). Specially shaped seamless steel pipes are widely used in various structural components, tools, and mechanical components. Compared with circular pipes, special-shaped pipes generally have larger moments of inertia and cross-sectional modulus, and have greater bending and torsion resistance, which can greatly reduce structural weight and save steel.