1, classified by production mode
Stainless steel pipe fittings are divided into two types: seamless pipe fittings and seamed pipe fittings according to the production method. Seamless stainless steel pipe fittings can be divided into butt welded stainless steel pipe fittings, forged stainless steel pipe fittings, threaded stainless steel pipe fittings, stainless steel low-pressure pipe fittings, and stainless steel high-pressure pipe fittings.
2, according to the shape of the section
Stainless steel pipe fittings can be divided into round pipes and special-shaped pipes according to the cross-sectional shape. The special-shaped tube has a rectangular tube, a rhombic tube, an elliptical tube, a hexagonal tube, an eight-sided tube, and various cross-section asymmetric tubes. Shaped tubes are widely used in a variety of structural parts, tools and mechanical parts. Compared with the round pipe, the special-shaped pipe generally has a large moment of inertia and a section modulus, and has a large bending and torsion resistance, which can greatly reduce the structural weight and save steel. Stainless steel pipes can be divided into equal-section pipes and variable-section pipes according to the longitudinal section shape. The variable section pipe has a conical tube, a stepped tube and a periodic section tube.
3, by material classification
Stainless steel pipe fittings are divided into ordinary carbon steel pipes, high-quality carbon structural steel pipes, alloy structural pipes, alloy steel pipes, bearing steel pipes, stainless steel pipes, and bimetallic composite pipes, coatings and coating pipes for saving precious metals and meeting special requirements. .
4, according to the shape of the tube end
Stainless steel pipe fittings can be divided into light pipes and wire pipes (threaded steel pipes) according to the state of the pipe ends. The wire tube can be divided into ordinary wire tube (transporting water, gas and other low pressure tubes, using ordinary cylindrical or conical tube thread connection) and special threaded tubes (oil, geological drilling tubes, for important wire tubes) Special threaded connection) For some special tubes, in order to compensate for the influence of the thread on the strength of the tube end, the tube end is usually thickened (inner thickening, outer thickening or inner and outer thickening) before the wire.
5. Classification by purpose
According to the use, it can be divided into oil well pipe fittings (casing, oil pipe and drill pipe, etc.), pipeline pipe, boiler pipe, mechanical structural pipe, hydraulic pillar pipe, gas cylinder pipe, geological pipe, chemical pipe (high pressure fertilizer pipe, petroleum cracking pipe). ) and ship fittings, etc.
6. Classification by production method
1. Seamless stainless steel pipe fittings - hot rolled pipe, cold rolled pipe, cold drawn pipe, extruded pipe, top pipe;
2, welded pipe:
1 according to the process points - arc welded pipe, electric resistance welded pipe (high frequency, low frequency), gas welded pipe, furnace welded pipe
2 according to the weld seam - straight seam welded pipe, spiral welded pipe
7. Classification by section shape
1. Simple section steel pipe - round steel pipe, square steel pipe, elliptical steel pipe, triangular steel pipe, hexagonal steel pipe, diamond steel pipe, octagonal steel pipe, semicircular steel circle, other
2, concave steel pipe, melon-shaped steel pipe, conical steel pipe, corrugated steel pipe, case steel pipe, other
Eight, according to wall thickness classification
Thin-walled steel pipe fittings and thick-walled steel pipe fittings.