According to the production method: steel pipes are divided into two categories: seamless pipes and welded pipes. Seamless steel pipes can be divided into hot-rolled pipes, cold-rolled pipes, cold-drawn pipes and extruded pipes; cold drawing and cold rolling are secondary processing of steel pipes; welded pipes are divided into straight seam welded pipes and spiral welded pipes.
According to the cross-sectional shape of steel pipes: they can be divided into round pipes and special-shaped pipes according to the cross-sectional shape; special-shaped pipes include rectangular pipes, diamond pipes, elliptical pipes, hexagonal pipes, octagonal pipes and various asymmetric pipes; according to the longitudinal section shape, they can be divided into equal section pipes and variable section pipes; variable section pipes include tapered pipes, stepped pipes and periodic section pipes.
According to the material of steel pipes: steel pipes are divided into ordinary carbon steel pipes, carbon structural steel pipes, alloy structural pipes, alloy steel pipes, bearing steel pipes, stainless steel pipes, and bimetallic composite pipes, plating and coating pipes to save precious metals and meet special requirements.
According to the shape of the pipe end: according to the state of the pipe end, it can be divided into smooth pipes and threaded pipes (threaded steel pipes). Threaded pipes can be divided into ordinary threaded pipes (pipes for conveying water, gas, etc. at low pressure, connected by ordinary cylindrical or conical pipe threads) and special threaded pipes (pipes for petroleum and geological drilling, connected by special threads, for important threaded pipes). For some special pipes, in order to compensate for the influence of threads on the strength of pipe ends, the pipe ends are usually thickened before threading (inner thickening, outer thickening or inner and outer thickening).
According to the purpose: oil well pipes (casing, oil pipes and drill pipes, etc.), pipeline pipes, boiler pipes, mechanical structure pipes, hydraulic support pipes, gas cylinder pipes, geological pipes, chemical pipes (high-pressure fertilizer pipes, petroleum cracking pipes), ship pipes, etc.
tructural seamless pipe
