We classify stainless steel pipes according to: according to production method, according to section shape, according to material, according to tube end shape, according to use, according to production method, according to section shape, according to wall thickness.
1. Classification by production method, etc.
Stainless steel pipes are divided into two categories: seamless pipes and welded pipes according to production methods. Seamless steel pipes can be divided into hot-rolled pipes, cold-rolled pipes, cold-drawn pipes and extruded pipes. Cold-drawn and cold-rolled pipes are the secondary Processing; welded pipes are divided into straight seam welded pipes and spiral welded pipes.
2. Classification by section shape
Stainless steel pipes can be divided into round pipes and special-shaped pipes according to the cross-sectional shape. Special-shaped tubes include rectangular tubes, diamond-shaped tubes, elliptical tubes, hexagonal tubes, octagonal tubes and various asymmetrical tubes. Special-shaped tubes are widely used in various structural parts, tools and mechanical parts. Compared with the round pipe, the special-shaped pipe generally has a larger moment of inertia and section modulus, and has a larger resistance to bending and torsion, which can greatly reduce the weight of the structure and save steel. Stainless steel pipes can be divided into equal-section pipes and variable-section pipes according to the shape of the longitudinal section. Variable section tubes include tapered tubes, stepped tubes and periodic section tubes.
3. Classification by material
Stainless steel pipes 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 (such as 304 stainless steel pipes) and bimetallic composite pipes for saving precious metals and meeting special requirements. Coated and coated pipes, etc.
4. Classification according to the shape of the pipe end
Stainless steel pipes can be divided into light pipes and wire pipes (threaded steel pipes) according to the state of the pipe ends. The threading pipe can be divided into ordinary threading pipe (pipes for low-pressure transportation of water, gas, etc., which are connected by ordinary cylindrical or conical pipe threads) and special threaded pipes (pipes for petroleum and geological drilling. For important threading pipes, use Special threaded connection), for some special pipes, in order to make up for the influence of the thread on the strength of the pipe end, the pipe end is usually thickened (internal thickening, external thickening or internal and external thickening) before threading.
5. Classification by use
According to the application, it can be divided into oil well pipe (casing, oil pipe and drill pipe, etc.), line pipe, boiler pipe, mechanical structure pipe, hydraulic prop pipe, gas cylinder pipe, geological pipe, chemical pipe (high pressure fertilizer pipe, oil cracking pipe) ) and marine pipes, etc.
6. Classification by production method
1. Seamless pipe - hot-rolled pipe, cold-rolled pipe, cold-drawn pipe, extruded pipe, pipe jacking;
2. Welded pipe
① According to the process - arc welded pipe, electric resistance welded pipe (high frequency, low frequency), gas welded pipe, furnace welded pipe;
② According to the welding seam - straight seam welded pipe, spiral welded pipe;
7. Classification by section shape
1. Simple section steel pipes - round steel pipes, square steel pipes, oval steel pipes, triangular steel pipes, hexagonal steel pipes, diamond-shaped steel pipes, octagonal steel pipes, semi-circular steel pipes, others;
2. Steel pipes with complex sections - unequal hexagonal steel pipes, five-petal plum-shaped steel pipes, double-convex steel pipes, double-concave steel pipes, melon-shaped steel pipes, conical steel pipes, corrugated steel pipes, case steel pipes, and others.
8. Classification by wall thickness
Thin-walled steel pipe, thick-walled steel pipe.
9. Other sub-categories
(1) Classification of welded pipes
It is further divided into general welded pipe, galvanized welded pipe, oxygen-blown welded pipe, wire casing, metric welded pipe, idler pipe, deep well pump pipe, automobile pipe, transformer pipe, electric welding thin-walled pipe, electric welding special-shaped pipe and spiral welded pipe.
①General welded pipe: General welded pipe is used to transport low-pressure fluid. Made of Q195A, Q215A, Q235A steel. Also available in other mild steels that are easy to weld. The steel pipe needs to be tested for water pressure, bending, flattening, etc., and has certain requirements on the surface quality. Usually, the delivery length is 4-10m, and it is often required to deliver to a fixed length (or multiple feet). The specification of the welded pipe is expressed by the nominal diameter (mm or inch). The nominal diameter is different from the actual one. The welded pipe has two types of ordinary steel pipe and thickened steel pipe according to the specified wall thickness.
②Galvanized steel pipe: In order to improve the corrosion resistance of the steel pipe, the general steel pipe (black pipe) is galvanized. Galvanized steel pipe is divided into two types: hot-dip galvanized and electric steel zinc. The hot-dip galvanized galvanized layer is thick and the cost of electro-galvanized is low.
③ Oxygen-blown welded pipe: used as a steel-making oxygen-blown pipe, generally small-diameter welded steel pipes, with eight specifications ranging from 3/8 inches to 2 inches. Made with 08, 10, 15, 20 or Q195-Q235 steel strip. In order to prevent corrosion, some are aluminized.
④ Wire casing: that is, ordinary carbon steel electric welded steel pipe, used in concrete and various structural power distribution projects, and the commonly used nominal diameter is from 13-76mm. The wall of the wire sleeve is relatively thin, and most of them are used after coating or galvanizing, and a cold bending test is required.
⑤ Metric welded pipe: The specification is used as a form of seamless pipe, and the welded steel pipe is expressed by outer diameter * wall thickness in mm. After welding, it is made by cold drawing method. Metric welded pipes are divided into general and thin-walled pipes. They are generally used as structural parts, such as drive shafts, or to transport fluids. Thin-walled pipes are used to produce furniture, lamps, etc., to ensure the strength and bending test of the steel pipe.
⑥Idler tube: It is used for electric welded steel pipe of belt conveyor idler, generally made of Q215, Q235A, B steel and 20 steel, with a diameter of 63.5-219.0mm. There are certain requirements for the curvature of the tube, the end face should be perpendicular to the center line, and the ovality. Generally, water pressure and flattening tests are carried out.
⑦Transformer tube: It is used to manufacture transformer radiator tubes and other heat exchangers. It is made of ordinary carbon steel and requires flattening, flaring, bending and hydraulic tests. The steel pipe is delivered in fixed length or double length, and there are certain requirements for the bending degree of the steel pipe.
⑧Special-shaped pipes: square pipes, rectangular pipes, hat-shaped pipes, and hollow rubber steel doors and windows welded by ordinary carbon-structured steel and 16Mn steel strips, mainly used for agricultural machinery parts, steel windows and doors, etc.
⑨ Electric welding thin-walled pipe: mainly used for making furniture, toys, lamps, etc. In recent years, thin-walled tubes made of stainless steel strips have been widely used in high-end furniture, decoration, and fences.
⑩ Spiral welded pipe: It is made by rolling low carbon carbon structural steel or low alloy structural steel strip at a certain helical angle (called forming angle) into a tube blank, and then welding the pipe seams. of strip steel for the production of large diameter pipes. Spiral welded pipes are mainly used for oil and natural gas transmission pipelines, and their specifications are expressed by outer diameter * wall thickness. Spiral welded pipes are single-sided welded and double-sided welded. The welded pipe should ensure that the hydraulic test, the tensile strength of the welded seam and the cold bending performance must meet the regulations.
(2) Classification of spiral tubes
Spiral seam submerged arc welded pipe for pressurized fluid transportation is mainly used for pipelines for transporting oil and natural gas. The steel pipe has strong pressure bearing capacity and good plasticity, which is convenient for welding and processing. Submerged arc welded steel pipes made by submerged arc welding or single-sided welding are used for general low-pressure fluid transportation such as water, gas, air and steam.
(3) Classification of bearing steel
At present, there are five main categories of bearing steels used in countries around the world, namely high carbon chromium bearing steel, carburized bearing steel, stainless bearing steel, high temperature bearing steel, and medium carbon bearing steel.