Definition of seamless steel pipe

A steel pipe made of a single piece of metal without seams on the surface is called a seamless steel pipe. According to the production method, seamless steel pipes are divided into hot rolled tubes, cold rolled tubes, cold drawn tubes, extruded tubes, and jacked tubes. According to the cross-sectional shape, seamless steel pipes are divided into two types: round and special. The special-shaped tubes have various complex shapes such as square, oval, triangle, hexagon, melon, star, and finned tube. The maximum diameter is 650 mm and the minimum diameter is 0.3 mm. Depending on the application, there are thick-walled pipes and thin-walled pipes. Seamless steel pipes are mainly used for petroleum geological drilling pipes, cracking pipes for petrochemicals, boiler tubes, bearing tubes, and high-precision structural steel pipes for automobiles, tractors, and aviation.

Classification of seamless steel pipe

Jointless steel pipe along the perimeter of its cross section. According to different production methods, it is divided into hot-rolled pipe, cold-rolled pipe, cold-drawn pipe, extruded pipe, pipe jack, etc., all have their own process regulations. Materials are ordinary and high-quality carbon structural steel, low alloy steel, alloy steel, stainless acid-resistant steel, etc. According to the purpose, it is divided into two types: general purpose (for water transmission, gas pipelines and structural parts, mechanical parts) and special purpose (for boilers, geological exploration, bearings, acid resistance, etc.).

Uses of seamless steel pipe

Seamless steel pipes are very versatile. General purposeseamless steel pipes are rolled from ordinary carbon structural steel, low alloy structural steel or alloy structural steel, with the largest output, and are mainly used as pipelines or structural parts for transporting fluids. It is divided into three types 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. For steel pipes supplied according to categories a and b, if they are used to withstand liquid pressure, hydraulic tests are also required.

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 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, steel pipe is lighter in weight when it has the same bending and torsional strength, and it is an economical section steel.
Widely used in the manufacture of structural parts and mechanical parts, such as petroleum drill rods, automobile transmission shafts, bicycle frames, and steel scaffolding used in building construction. Man-hours have been widely used to manufacture steel pipes.