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 pipe jacking. According to the cross-sectional shape, the seamless steel pipe is divided into two types: round and special-shaped.

Seamless steel pipes are made of ordinary and carbon structural steel, low alloy steel, alloy steel, stainless acid-resistant steel, etc. According to the purpose, it is divided into two categories: 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.

Seamless steel pipes are supplied in three categories according to different uses: a. Supply according to chemical composition and mechanical properties; b. Supply according to mechanical properties; c. Supply according to hydraulic test. Steel pipes supplied according to categories a and b, if they are used to withstand liquid pressure, shall also be subjected to a hydrostatic test. 3. There are many kinds of seamless pipes for special purposes, such as seamless pipes for boilers, seamless pipes for chemical power, seamless pipes for geological use and seamless pipes for petroleum.

Seamless steel pipe has a hollow section and is widely used as a pipeline 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, the steel pipe is lighter in weight when the bending and torsional strength is the same, 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. The use of steel pipes to make ring parts can improve material utilization, simplify manufacturing processes and save money The material and processing time have been widely used in the manufacture of steel pipes.