The definition of seamless steel pipe is: a steel pipe made of a single piece of metal without seams on the surface. According to the production method, seamless pipes are divided into hot-rolled pipes, cold-rolled pipes, cold-drawn pipes, extruded pipes, and top pipes. According to the cross-sectional shape, seamless steel pipes are divided into two types: round and special-shaped. Special-shaped pipes include square, oval, triangular, hexagonal, melon seed, star, and finned pipes.
Seamless steel pipe materials include ordinary and high-quality carbon structural steel, low-alloy steel, alloy steel, stainless and acid-resistant steel, etc. According to the purpose, it is divided into two types: general purpose and special purpose. General-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, with a large output, and are mainly used as pipelines or structural parts for conveying fluids.
Seamless steel pipes are supplied in three categories according to different purposes: a. According to chemical composition and mechanical properties; b. According to mechanical properties; c. According to hydraulic test. Steel pipes supplied according to categories a and b, if used to withstand liquid pressure, shall also be subjected to a hydraulic test. 3. Special-purpose seamless pipes include seamless pipes for boilers, chemical and electric power, seamless steel pipes for geology, and seamless pipes for petroleum.
Seamless steel pipes have a hollow section and are used in large quantities as pipelines for transporting fluids, such as pipelines for transporting oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, steel pipe is lighter in flexural and torsional strength and is an economical section steel.
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. Steel pipes are used to make ring parts, which can improve material utilization, simplify manufacturing procedures, and save materials and processing. Working hours, steel pipes have been widely used for manufacturing.