Steel pipes without joints along the perimeter of their cross-section. According to different production methods, it can be divided into hot-rolled pipes, cold-rolled pipes, cold drawn pipes, extruded pipes, top pipes, etc., all with their own process regulations.
The materials include ordinary and high-quality carbon structural steel (Q215-A-Q275-A and 10-50 steel), low alloy steel (09MnV, 16Mn, etc.), alloy steel, stainless acid resistant steel, etc.
It is divided into two categories according to its purpose: general purpose (used for water and gas pipelines and structural components, mechanical parts) and specialized purpose (used for boilers, geological exploration, bearings, acid resistance, etc.).