Quilted steel pipe
1. Seamless steel pipe is perforated by the whole round steel, and the steel pipe without weld on the surface is called seamless steel pipe. According to the production method, seamless steel pipe can be divided into hot-rolled seamless steel pipe, cold-rolled seamless steel pipe, cold drawn seamless steel pipe, extruded seamless steel pipe, pipe jacking, etc. According to the section shape, seamless steel pipes are divided into circular and special-shaped pipes. Special-shaped pipes have a variety of complex shapes such as square, oval, triangular, hexagonal, melon seed, star and winged pipes. The maximum diameter is 900mm and the minimum diameter is 4mm. According to different uses, there are thick wall seamless steel pipe and thin wall seamless steel pipe. Seamless steel pipe is mainly used as petroleum geological drilling pipe, cracking pipe for petrochemical industry, boiler pipe, bearing pipe and high-precision structural steel pipe for automobile, tractor and aviation.
2. A steel pipe without joints along the periphery 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 jacking, etc., 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 and acid resistant steel, etc.
According to the purpose, it is divided into general purpose (for water transmission, gas pipeline, structural parts and mechanical parts) and special purpose (for boiler, geological exploration, bearing, acid resistance, etc.).