Classification Of Pipes

First, the classification of pipe

1, according to production methods

(1) seamless pipe - hot rolled tube, cold rolled tube, cold drawn tube, extruded tube, top tube

(2) welded pipe

(a) By process - arc welded pipe, resistance welded pipe (high frequency, low frequency), gas welded pipe, furnace welded pipe

(b) According to the welding seam - straight seam welded pipe, spiral welded pipe

2. Classified by section shape

(1) Simple section steel pipe - round steel pipe, square steel pipe, oval steel pipe, triangular steel pipe, hexagonal steel pipe, diamond steel pipe, octagonal steel pipe, semi-circular steel ball, other

(2) Steel tubes with complex sections - unequal hexagonal steel pipe, five-fractured plumbular steel pipe, double convex steel pipe, double-concave steel pipe, melon-shaped steel pipe, conical steel pipe, corrugated steel pipe, case steel pipe, and others

3, classified by wall thickness - thin-walled steel pipe, thick-walled steel pipe

4. According to the purpose of use - pipeline steel pipe, thermal equipment steel pipe, mechanical industrial steel pipe, petroleum, geological drilling steel pipe, container steel pipe, chemical industry steel pipe, special purpose steel pipe, other

Second, seamless steel pipe

It is a long steel bar with a hollow section and no joints around it. The steel pipe has a hollow cross-section and is used in large quantities as a pipe for conveying fluids, such as pipes for transporting petroleum, natural gas, coal gas, water, and certain solid materials. Compared with solid steel such as round steel, steel pipes have a lighter weight when subjected to the same flexural and torsional strength, and are economical cross-section steels. They are widely used in the manufacture of structural and mechanical parts such as oil drill pipes, automobile transmission shafts, and bicycles. Frames and steel scaffolds used in construction. The use of steel pipes for the manufacture of annular parts can increase the material utilization, simplify the manufacturing process, save material and processing man-hours, such as rolling bearing rings, jack sleeves, etc. Currently, steel pipes are widely used for manufacturing. Steel pipe is also an indispensable material for various conventional weapons. The barrels, barrels, etc. must be made of steel pipes. Steel tubes can be divided into round tubes and shaped tubes according to the shape of the cross-sectional area. Since the circle area is the largest under the condition of the same circumference, more fluid can be transported by the circular tube. In addition, when the ring section is subjected to internal or external radial pressure, the force is more uniform. Therefore, most steel pipes are round pipes.

However, the circular tube also has certain limitations. For example, under the conditions of plane bending, the circular tube is not as strong as the square and rectangular tube, and some agricultural machinery skeletons, steel-wood furniture, etc. are commonly used and rectangular tubes. According to different uses also need to have other cross-sectional shape of the special-shaped steel pipe.

1. Seamless steel pipe for structural use (GB/T8162-1999) is a seamless steel pipe for general structure and mechanical structure.

2. Seamless steel pipe for fluid transportation (GB/T8163-1999) is a general seamless steel pipe used to transport fluid such as water, oil, and gas.

3. Seamless steel tubes for low and medium pressure boilers (GB3087-1999) are used to manufacture various types of low and medium pressure boiler superheated steam pipes, boiling water pipes and superheated steam pipes for boilers, large smoke pipes, small smoke pipes and arch bricks. High-quality carbon structural steel for hot-rolled and cold drawn (rolled) seamless steel tubes.

4. Seamless steel tubes for high-pressure boilers (GB5310-1995) are high-quality carbon steel, alloy steel and stainless heat-resistant seamless steel tubes for the heating surface of water-tube boilers used to produce high pressure and higher pressures.

5. High-pressure seamless steel tubes for chemical fertilizer equipment (GB6479-86) are high-quality carbon structural steel and alloy steel seamless tubes suitable for chemical equipment and pipelines with an operating temperature of -40 to 400°C and a working pressure of 10 to 30 Ma.

6. Seamless Steel Pipe for Petroleum Cracking (GB9948-88) is a seamless steel pipe for furnace tubes, heat exchangers and pipes in petroleum refineries.

7. Steel pipes for geological drilling (YB235-70) are steel pipes used by the geological department for core drilling. They can be divided into drill pipes, drill collars, core pipes, casing pipes, and sedimentation pipes according to their purposes.

8. Diamond core drilling seamless steel pipe (GB3423-82) is a seamless steel pipe used for drilling of diamond cores, core rods, and casing.

9. The oil drilling pipe (YB528-65) is a seamless steel pipe used for thickening or thickening at both ends of oil drilling. The steel pipe is divided into two types, namely the sub-car wire and the non-car wire, and the wire pipe is connected with the joint. The butt welding method of the wire car pipe is connected with the tool joint.

10. Carbon steel seamless steel tubes for ships (GB5213-85) are carbon steel seamless tubes for the production of Class I pressure piping systems, Class II pressure piping systems, boilers and superheaters for ships. Carbon steel seamless steel pipe wall temperature does not exceed 450 °C, alloy steel seamless pipe wall temperature exceeds 450 °C.

11. Seamless steel tubes for automotive half-axle casing (GB3088-82) are high-quality carbon structural steel and alloy structural steel hot-rolled seamless steel tubes for the manufacture of automobile axle bushings and drive axle housings.

12. The high-pressure fuel pipe for diesel engines (GB3093-86) is a cold-drawn seamless steel pipe for the high pressure pipes used in the manufacture of diesel injection systems.

13. Precision inner diameter seamless steel tubes for hydraulic and pneumatic cylinders (GB8713-88) are precision-drawn or cold-rolled precision seamless steel tubes with precision inner diameter dimensions for the manufacture of hydraulic and pneumatic cylinders.

14. Cold-drawn or cold-rolled precision seamless steel tubes (GB3639-83) are cold-drawn or cold-rolled precision seamless steel tubes for mechanical structures and hydraulic equipment with high dimensional accuracy and good surface finish.

The use of precision seamless steel pipe manufacturing machinery structures or hydraulic equipment, etc., can greatly reduce the mechanical processing time, improve the material utilization, and help improve product quality.

15. Structural stainless steel seamless pipes (GB/T14975-1994) are hot-rolled stainless steels that are widely used in corrosion-resistant pipes and structural parts and components in the chemical, petroleum, textile, medical, food, and machinery industries. Squeeze, expand) and cold drawn (rolled) seamless steel tubes.

16. Stainless Steel Seamless Pipe for Fluid Conveyance (GB/T14976-1994) is a hot rolled (extruded, expanded) and cold drawn (rolled) seamless steel pipe made of stainless steel for conveying fluids.

17. Shaped seamless steel tubes are the general term for seamless steel tubes of other cross-sectional shapes than circular tubes. According to the different shapes and sizes of steel pipe sections, they can be divided into equal-wall thickness special-shaped seamless steel pipes (code D), unequal wall thickness profiled seamless steel pipes (codenamed BD) and variable-diameter special-shaped seamless steel pipes (coded as BJ). Shaped seamless steel tubes are widely used in various structural parts, tools and mechanical parts. Compared with round tubes, shaped tubes generally have larger moments of inertia and section modulus, and have greater resistance to bending and torsion, which can greatly reduce the structural weight and save steel.

Third, welded steel pipe

Welded steel pipe, also called welded pipe, is a steel pipe made by welding a steel plate or strip after crimping. Welded steel pipe production process is simple, high production efficiency, variety specifications, equipment, less, but the general strength is lower than the seamless steel pipe. Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the advancement of welding and inspection technologies, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have been increasing, and they have been replaced in more and more fields. Steel pipe. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes in the form of welds.

The straight seam welded pipe has a simple production process, high production efficiency, low cost, and rapid development. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe. A narrower blank can be used to produce a larger diameter pipe, and a blank having a different diameter can be produced from a blank of the same width. However, compared with the straight seam pipe of the same length, the length of the weld seam increases by 30 to 100%, and the production speed is low.

Therefore, the smaller diameter welded pipe mostly adopts the straight seam welding, and the large diameter welded pipe adopts the spiral welding.

1. Welded steel pipes for low-pressure fluid delivery (GB/T3092-1993) are also called general welded pipes, commonly known as black pipes. It is a welded steel pipe used for the transportation of water, gas, air, oil and heating steam, and other generally lower pressure fluids and other uses. The wall thickness of the steel pipe is divided into ordinary steel pipe and thick steel pipe; the pipe end is divided into non-threaded steel pipe (light pipe) and threaded steel pipe. The specification of the steel pipe is expressed by the nominal diameter (mm), and the nominal diameter is the approximate value of the internal diameter. Commonly used in inches, such as 1 1/2 and so on. The welded steel pipe used for low-pressure fluid transportation is not only directly used for conveying fluids, but also used as a raw pipe for galvanized welded steel pipes for low-pressure fluid transportation.

2. Galvanized welded steel pipe for low pressure fluid delivery (GB/T3091-1993), also known as galvanized welded steel pipe, commonly known as white pipe. It is a hot-dip galvanized welded (furnace or welded) steel pipe for general low pressure fluids such as water, gas, air oil, heating steam, and warm water. The wall thickness of the steel pipe is divided into ordinary galvanized steel pipe and thick galvanized steel pipe; the pipe end is divided into non-threaded galvanized steel pipe and threaded galvanized steel pipe. The specification of the steel pipe is expressed by the nominal diameter (mm), and the nominal diameter is the approximate value of the internal diameter. Commonly used in inches, such as 1 1/2 and so on.

3. Ordinary carbon steel wire bushings (GB3640-88) are steel tubes used to protect wires in electrical and industrial installations such as industrial and civil buildings and installation machinery and equipment.

4. Straight seam welded steel pipes (YB242-63) are longitudinally parallel steel pipes with welded seams. Usually divided into metric welded steel pipe, welded thin-walled pipe, transformer cooling oil pipe and so on.

5. Spiral seam submerged arc welded steel pipe for pressure fluid transport (SY5036-83) is a hot rolled steel strip used as tube blank, which is often temperature spirally molded, and welded by double sided submerged arc welding method for pressure fluid transport. Spiral seam steel pipe. The steel pipe has strong pressure bearing capacity and good welding performance. After various rigorous scientific tests and tests, it is safe and reliable to use. Large diameter steel pipe, high transmission efficiency, and can save investment in laying pipelines. Mainly used for the transportation of petroleum and natural gas pipelines.

6. Spiral seam high-frequency welded steel pipe for conveying fluids (SY5038-83) is a hot-rolled steel strip used as a tube blank, which is heated at regular temperature by spiral molding and welded by high-frequency lap welding method for pressurized fluid conveying. Spiral seam high frequency welded steel pipe. The steel pipe has strong pressure bearing capacity, good plasticity, and is easy to be welded and processed. After a variety of strict and scientific inspections and tests, it is safe and reliable to use, the diameter of the steel pipe is large, the transmission efficiency is high, and investment in laying pipelines can be saved. Mainly used for laying pipelines for transporting oil, natural gas, etc.

7. Spiral submerged arc welded steel pipe (SY5037-83) for low-pressure fluid delivery is a hot-rolled steel strip used as a tube blank, which is usually thermo-screwed and is made of double-sided automatic submerged arc welding or single-sided welding. Submerged arc welded steel pipes for general low pressure fluids such as water, gas, air and steam.

8. Spiral seam high-frequency welded steel pipe (SY5039-83) for general low-pressure fluid transmission is a hot-rolled steel strip used as a tube blank, which is usually temperature spirally molded, and welded by high-frequency lap welding method for general low-pressure fluid conveying spirals. Seam high frequency welded steel pipe.

9. Spiral welded steel pipe for piles (SY5040-83) is made of hot-rolled steel strip for tube blanks. It is usually formed by spiral molding and is made of double-sided submerged arc welding or high-frequency welding. It is used for civil construction structures and piers. , bridges and other foundation pile steel pipe.

Fourth, steel-plastic composite pipe, large diameter coated steel pipe

The steel-plastic composite pipe is made of hot-dip galvanized steel pipe as the base body, and is coated with powder by the powder melting and spraying technology on the inner wall (when the outer wall is needed). Compared with galvanized pipe, it has the advantages of corrosion resistance, no rust, no fouling, smooth and smooth, clean and non-toxic, and long service life. According to testing, the service life of steel-plastic composite pipe is more than three times that of galvanized pipe. Compared with plastic pipe, it has the advantages of high mechanical strength, pressure resistance, heat resistance and so on. Since the substrate is a steel pipe, there is no problem of embrittlement and aging. Can be widely used in tap water, gas, chemical products and other fluid transportation and heating engineering, is the upgrading of galvanized pipe products. As its installation and use methods are basically the same as those of traditional galvanized pipes, the form of pipe fittings is also the same, and it can replace aluminum-plastic composite pipe to play a role in the transportation of large-diameter tap water. It is welcomed by users and has become the most competitive pipeline market. One of the new products.

Coated steel pipe is made of plastic coated with large-diameter spiral welded pipe and high-frequency welded pipe. The maximum nozzle diameter is 1200mm. It can be coated with PVC, PE, epoxy according to different needs. Resin (EPOZY) and other various properties of plastic coating, good adhesion, strong corrosion resistance, resistant to strong acids, alkalis and other chemical corrosion, non-toxic, no rust, wear resistance, impact resistance, strong permeability The surface of the pipeline is smooth and does not adhere to any substance, which can reduce the resistance during transportation, increase the flow rate and transmission efficiency, and reduce the pressure loss of the transmission. There is no solvent in the coating, no leakage of substances, so it will not contaminate the transported media, so as to ensure the purity and sanitation of the fluid. It can be used alternately in the range of -40°C to +80°C, without aging, Because it does not crack, it can be used in harsh environments such as cold areas.

Large diameter coated steel pipes are widely used in tap water, natural gas, petroleum, chemical, pharmaceutical, telecommunications, electric power, marine and other engineering fields.

The use of the classification of pipes

First, steel pipe

According to its manufacturing method, steel pipes are divided into two kinds: seamless steel pipes and welded steel pipes. Seamless steel tubes are made of high-quality carbon steel or alloy steel, with hot rolling, cold rolling (pulling). Welded steel tubes are made by rolling into a tube-shaped steel plate and welded to a seam or spiral seam. In terms of manufacturing methods, they are divided into welded steel pipes for low-pressure fluid transportation, spiral welded steel pipes, direct welded steel tubes, and welded pipes. Seamless steel tubes can be used for various liquid and gas pipelines. Welding pipes can be used for water pipelines, gas pipelines, heating pipes, etc.

1, welded steel pipe

1.1 Welded steel pipe for low pressure fluid delivery and galvanized welded steel pipe

The welded steel pipe for low-pressure fluid transportation is made of carbon mild steel and is the most commonly used small-diameter pipe material in pipeline engineering. It is suitable for conveying water, coal gas, steam and other media. It is divided into plates according to the surface quality. Zinc pipes (commonly known as white iron pipes) and non-galvanized pipes (commonly known as black iron pipes). The inner and outer walls are coated with a zinc protective layer that is about 3% to 6% heavier than non-galvanized ones. According to the different wall thickness of the pipe, it can be divided into three types: thin-walled pipe, ordinary pipe and thickened pipe. Thin-walled tubes are not suitable for conveying media and can be used as a sleeve.

1.2 Straight seam welded steel pipe

Straight seam coiled welded steel pipe can be divided into electric welded steel pipe and site-used steel plate and rolled and welded into straight seam welded steel pipe. Several wall thicknesses can be made.

1.3 spiral seam welded steel pipe

Spiral seam welded steel pipe is divided into automatic submerged arc welded steel pipe and high frequency welded steel pipe.

a. Spiral seam automatic submerged arc welded steel pipes are classified into two types: Class A pipe and Class B pipe according to the pressure of the medium. Class A pipe is generally welded with common carbon steel Q235, Q235F and general low alloy structural steel 16Mn, and class B pipe is welded with steel Q235, Q235F, Q195, etc., used as low pressure fluid conveying pipe

b. Spiral seam high-frequency welded steel pipe Spiral high-frequency welded steel pipe, there is no unified product standard, generally using common carbon steel Q235, Q235F and other steel manufacturing.

2, seamless steel pipe

Seamless steel tubes are classified into hot rolled tubes and cold drawn (rolled) tubes according to the manufacturing method. The nominal diameter of the cold drawn (rolled) tube is 200 mm, and the maximum nominal diameter of the hot rolled tube is 600 mm. In pipeline engineering, when the pipe diameter exceeds 57mm, hot-rolled pipes are often used. When the pipe diameter is less than 57mm, cold-drawn (rolled) pipes are often used. Pipeline engineering commonly used seamless steel pipe has the following three kinds:

2.1 General seamless steel pipe

Generally not available