Seamless Steel Pipes Seamless steel pipe made from a whole piece of metal with no seams on the surface is called seamless steel pipe. According to the production method, seamless pipe is divided into hot-rolled pipe, cold-rolled pipe, cold-drawn pipe, extruded pipe, top pipe, etc. According to the shape of the section, seamless steel pipe is divided into two kinds of round and shaped, shaped pipe has a square, oval, triangular, hexagonal, melon, star, with a variety of complex shapes finned tube. The maximum diameter is 650mm, and the minimum diameter is 0.3mm. depending on the application, there are thick-walled and thin-walled tubes. Seamless steel tubes are mainly used as petroleum geological drilling tubes, petrochemical cracking tubes, boiler tubes, bearing tubes, and high-precision structural steel tubes for automobiles, tractors, and aviation. Seamless steel pipe classification: steel pipe without seams along the perimeter of its cross-section. According to the different production methods are divided into hot-rolled tubes, cold-rolled tubes, cold-drawn tubes, extruded tubes, top tubes, etc., all have their own process regulations. Materials include ordinary and high-quality carbon structural steel (Q215-A to Q275-A and 10-50 gauge steel), low-alloy steel (09MnV, 16Mn, etc.), alloy steel, stainless acid-resistant steel, etc. According to the use is divided into general purpose (for water and gas pipelines and structural parts, mechanical parts) and special (for boilers, geological exploration, bearings, acid resistance, etc.) two categories.

Seamless steel pipe is widely used. General purpose seamless steel pipe is rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, the largest production volume, mainly used as a pipeline or structural parts for the transport of fluids. .2, according to the use of different types of supply: a, according to the chemical composition and mechanical properties of supply; b, according to the mechanical properties of supply; c, according to the hydraulic test supply. Steel pipes supplied according to category a and b are also subjected to hydrotesting if they are used to withstand liquid pressure.3. Seamless pipes for special purposes include seamless pipes for boilers, chemical power, seamless steel pipes for geological purposes and seamless pipes for petroleum purposes, and many others.

Seamless steel pipe has a hollow cross-section and is used in large quantities 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 the bending and torsional strength is the same, and is an economic cross-sectional steel. Widely used in the manufacture of structural and mechanical parts, such as oil drilling rods, automobile transmission shafts, bicycle frames and steel scaffolding used in building construction, etc. The use of steel pipe manufacturing ring parts, can improve material utilization, simplify the manufacturing process, save materials and processing time, has been widely used to manufacture steel pipe.