Steel pipe knowledge_Shanghai Tianyang Steel Pipe Co., Ltd

1、 Classification of pipes
1. Classified by production method
(1) Seamless pipe - hot-rolled pipe, cold-rolled pipe, cold drawn pipe, extruded pipe, top pipe
(2) Welded pipe
(a) Divided by process - arc welded pipe, resistance welded pipe (high-frequency, low-frequency), gas welded pipe, furnace welded pipe
(b) Classified by weld seam - straight seam welded pipe, spiral welded pipe
2. Classified by cross-sectional shape
(1) Simple section steel pipe - circular steel pipe, square steel pipe, elliptical steel pipe, triangular steel pipe, hexagonal steel pipe, diamond steel pipe, octagonal steel pipe, semi-circular steel pipe, other
(2) Complex cross-section steel pipe - unequal hexagonal steel pipe, five petal plum blossom shaped steel pipe, double convex steel pipe, double concave steel pipe, melon seed shaped steel pipe, conical steel pipe, corrugated steel pipe, watch case steel pipe, other
3. Classified by wall thickness
Thin walled steel pipe, thick walled steel pipe
4. Classified by purpose
Steel pipes for pipelines, thermal equipment, mechanical industry, petroleum and geological drilling, container, chemical industry, special purpose, and others
2、 Seamless steel pipe
It is a long strip of steel with a hollow cross-section and no seams around it. Steel pipes have a hollow cross-section and are widely used as pipelines for transporting fluids, such as oil, natural gas, coal gas, water, and certain solid materials. Compared with solid steel materials such as round steel, steel pipes are lighter in weight when their bending and torsional strength is the same. They are an economical cross-sectional steel material widely used in the manufacture of structural and mechanical parts, such as oil drill rods, automotive transmission shafts, bicycle frames, and steel scaffolding used in construction. Using steel pipes to manufacture circular parts can improve material utilization, simplify manufacturing processes, save materials and processing time, such as rolling bearing rings, jack sleeves, etc. Currently, steel pipes are widely used for manufacturing. Steel pipes are still an indispensable material for various conventional weapons, such as gun barrels and cannon barrels, which require steel pipes for manufacturing. Steel pipes can be divided into circular pipes and special-shaped pipes according to their cross-sectional area and shape. Due to the fact that the circular area is the largest under the condition of equal circumference, a circular tube can transport more fluid. In addition, when subjected to internal or external radial pressure, the circular cross-section is subjected to more uniform force, therefore, the vast majority of steel pipes are circular. (021-57590228 )
However, circular pipes also have certain limitations. For example, under the condition of planar bending, circular pipes have lower bending strength than square and rectangular pipes. Some agricultural machinery skeletons, steel and wood furniture, etc. commonly use square and rectangular pipes. Different cross-sectional shapes of special-shaped steel pipes are required for different purposes.
1. Seamless steel pipes for structural use (GB/T8162-1999) are seamless steel pipes used for general and mechanical structures.
2. Seamless steel pipes for fluid transportation (GB/T8163-1999) are general seamless steel pipes used for transporting fluids such as water, oil, and gas.
3. Seamless steel pipes for low and medium pressure boilers (GB3087-1999) are high-quality carbon structural steel hot-rolled and cold drawn (rolled) seamless steel pipes used for manufacturing various structures of superheated steam pipes, boiling water pipes, and superheated steam pipes, large smoke pipes, small smoke pipes, and arch brick pipes for locomotive boilers.
4. Seamless steel pipes for high-pressure boilers (GB5310-1995) are high-quality carbon steel, alloy steel, and stainless heat-resistant seamless steel pipes used for manufacturing the heating surface of water tube boilers with high pressure and above.
5. High pressure seamless steel pipes for fertilizer equipment (GB6479-2000) are high-quality carbon structural steel and alloy steel seamless steel pipes suitable for chemical equipment and pipelines with working temperatures of -40~400 ℃ and working pressures of 10~30Ma.
6. Seamless steel pipes for petroleum cracking (GB9948-88) are seamless steel pipes suitable for furnace tubes, heat exchangers, and pipelines in petroleum refineries.
7. Steel pipes for geological drilling (YB235-70) are used by geological departments for core drilling, which can be divided into drill rods, drill collars, core pipes, casing pipes, and sedimentation pipes according to their purposes.
8. Seamless steel pipes for diamond core drilling (GB3423-82) are seamless steel pipes used for drill rods, core rods, and casing in diamond core drilling.
9. Oil drilling pipe (YB528-65) is a seamless steel pipe used for oil drilling with inner or outer thickening at both ends. Steel pipes are divided into two types: threaded and non threaded. Threaded pipes are connected with joints, while non threaded pipes are connected with tool joints by butt welding. (021-57590365)
10. Carbon steel seamless steel pipes for ships (GB5213-85) are carbon steel seamless steel pipes used for manufacturing Class I pressure resistant piping systems, Class II pressure resistant piping systems, boilers, and superheaters for ships. The working temperature of carbon steel seamless steel pipe wall shall not exceed 450 ℃, and the working temperature of alloy steel seamless steel pipe wall shall exceed 450 ℃.
11. Seamless steel pipes for automotive half shaft sleeves (GB3088-82) are high-quality carbon structural steel and alloy structural steel hot-rolled seamless steel pipes used for manufacturing automotive half shaft sleeves and drive axle housing shaft sleeves.
12. High pressure fuel pipes for diesel engines (GB3093-2002) are cold drawn seamless steel pipes used to manufacture high-pressure pipes for diesel injection systems.
13. Precision inner diameter seamless steel pipe for hydraulic and pneumatic cylinder tubes (GB8713-88) is a cold drawn or cold-rolled precision seamless steel pipe with precise inner diameter dimensions used for manufacturing hydraulic and pneumatic cylinder tubes.
14. Cold drawn or cold-rolled precision seamless steel pipe (GB3639-2000) is a type of precision seamless steel pipe with high dimensional accuracy and good surface smoothness used in mechanical structures and hydraulic equipment.
Choosing precision seamless steel pipes to manufacture mechanical structures or hydraulic equipment can greatly save machining hours, improve material utilization, and also contribute to improving product quality.
15. Seamless stainless steel pipes for structural use (GB/T14975-2002) are hot-rolled (extruded, expanded) and cold drawn (rolled) seamless steel pipes made of stainless steel, widely used in industries such as chemical, petroleum, textile, medical, food, machinery, etc., for corrosion-resistant pipelines, structural components, and parts.
16. Seamless stainless steel pipes for fluid transportation (GB/T14976-2002) are hot-rolled (extruded, expanded) and cold drawn (rolled) seamless steel pipes made of stainless steel used for fluid transportation.
17. Irregular seamless steel pipe is a general term for seamless steel pipes with cross-sectional shapes other than round pipes. According to the different cross-sectional shapes and sizes of steel pipes, they can be divided into equal wall thickness irregular seamless steel pipes (code D), unequal wall thickness irregular seamless steel pipes (code BD), and variable diameter irregular seamless steel pipes (code BJ). Irregular seamless steel pipes are widely used in various structural components, tools, and mechanical parts. Compared with circular pipes, special-shaped pipes generally have larger moments of inertia and section moduli, and have greater bending and torsional resistance, which can greatly reduce structural weight and save steel.
3、 Welded steel pipe
Welded steel pipe, also known as welded pipe, is a steel pipe made by welding steel plates or steel strips after curling and forming. The production process of welded steel pipes is simple, the production efficiency is high, there are many varieties and specifications, and the equipment resources are limited, but the strength is generally lower than that of seamless steel pipes. Since the 1930s, with the rapid development of high-quality strip rolling production and advances in welding and inspection technology, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have been increasing, replacing seamless steel pipes in more and more fields. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the form of the weld seam.
The production process of straight seam welded pipes is simple, with high production efficiency, low cost, and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. It can produce welded pipes with larger diameters using narrower billets, and can also produce welded pipes with different diameters using billets of the same width. However, compared to straight seam pipes of the same length, the weld seam length increases by 30-100%, and the production speed is lower.
Therefore, smaller diameter welded pipes mostly use straight seam welding, while large-diameter welded pipes mostly use spiral welding.
1. Welded steel pipes for low-pressure fluid transportation (GB/T3092-1993), also known as general welded pipes, commonly known as black pipes. It is a welded steel pipe used for transporting generally low-pressure fluids such as water, gas, air, oil, and heating steam, as well as for other purposes. The wall thickness of steel pipes is divided into ordinary steel pipes and thickened steel pipes; The form of the connecting end is divided into non threaded steel pipe (plain pipe) and threaded steel pipe. The specifications of steel pipes are expressed in nominal diameter (mm), which is an approximate value of the inner diameter. It is commonly expressed in inches, such as 11/2. Welded steel pipes for low-pressure fluid transportation are not only directly used for transporting fluids, but also widely used as raw pipes for galvanized welded steel pipes for low-pressure fluid transportation.
2. Galvanized welded steel pipes for low-pressure fluid transportation (GB/T3091-1993), also known as galvanized welded steel pipes, commonly known as white pipes. It is a hot-dip galvanized welded (furnace welding or electric welding) steel pipe used for transporting water, gas, air oil, heating steam, warm water and other generally low-pressure fluids or other purposes. The wall thickness of steel pipes is divided into ordinary galvanized steel pipes and thickened galvanized steel pipes; The types of takeover ends are divided into non threaded galvanized steel pipes and threaded galvanized steel pipes. The specifications of steel pipes are expressed in nominal diameter (mm), which is an approximate value of the inner diameter. It is commonly expressed in inches, such as 11/2. (Tianyang Steel Pipe)
3. Ordinary carbon steel wire conduit (GB3640-88) is a steel pipe used to protect wires in electrical installation projects such as industrial and civil buildings, and installation of machinery and equipment.
4. Straight seam welded steel pipe (YB242-63) is a steel pipe with a weld seam parallel to the longitudinal direction of the steel pipe. Usually divided into metric welded steel pipes, welded thin-walled pipes, transformer cooling oil pipes, etc.
5. Spiral seam submerged arc welded steel pipe (SY5036-83) for pressurized fluid transportation is a spiral seam steel pipe made of hot-rolled steel strip coil as pipe blank, formed by constant temperature spiral forming, welded by double-sided submerged arc welding method, and used for pressurized fluid transportation. Steel pipes have strong pressure bearing capacity and good welding performance. After various rigorous scientific inspections and tests, they are safe and reliable to use. The steel pipe has a large diameter, high conveying efficiency, and can save investment in laying pipelines. Mainly used for pipelines transporting oil and natural gas.
6. Spiral seam high-frequency welded steel pipe (SY5038-83) for pressurized fluid transportation is a spiral seam high-frequency welded steel pipe used for pressurized fluid transportation, which is made of hot-rolled steel strip coil as the pipe blank, formed by constant temperature spiral forming, and welded by high-frequency lap welding method. Steel pipes have strong pressure bearing capacity, good plasticity, and are easy to weld and process into shapes; After various strict and scientific inspections and tests, it is safe and reliable to use, with large steel pipe diameters, high conveying efficiency, and can save investment in laying pipelines. Mainly used for laying pipelines for transporting oil, natural gas, etc.
7. Spiral seam submerged arc welded steel pipes (SY5037-83) for general low-pressure fluid transportation are made of hot-rolled steel strip coils as pipe blanks, spiral formed at high temperatures, and made using double-sided automatic submerged arc welding or single-sided welding methods. They are used for submerged arc welded steel pipes for general low-pressure fluid transportation such as water, gas, air, and steam.
8. The spiral seam high-frequency welded steel pipe (SY5039-83) for general low-pressure fluid transportation is made of hot-rolled steel strip coil as the pipe blank, which is formed by constant temperature spiral welding and welded using high-frequency lap welding method for general low-pressure fluid transportation spiral seam high-frequency welded steel pipe. (www.steeltube-cn.com)
9. Spiral welded steel pipe for piles (SY5040-83) is made of hot-rolled steel strip coil as the pipe blank, formed by constant temperature spiral welding, and made by double-sided submerged arc welding or high-frequency welding. It is used as a steel pipe for foundation piles in civil construction structures, docks, bridges, etc.
4、 Steel plastic composite pipe, large-diameter coated steel pipe
Steel plastic composite pipes are made of hot-dip galvanized steel pipes as the matrix, and coated with plastic on the inner wall (or outer wall if necessary) through powder melting spraying technology, with excellent performance. Compared with galvanized pipes, it has the advantages of corrosion resistance, non rusting, non scaling, smoothness, cleanliness and non toxicity, and long service life. According to testing, the service life of steel plastic composite pipes is more than three times that of galvanized pipes. Compared with plastic pipes, it has the advantages of high mechanical strength, good pressure resistance, and heat resistance. Due to the fact that the substrate is made of steel pipe, there are no issues of embrittlement or aging. It can be widely used in fluid transportation and heating projects such as tap water, gas, and chemical products, and is an upgraded product of galvanized pipes. Due to its installation and usage method being basically the same as traditional galvanized pipes, the form of pipe fittings is also completely the same, and it can replace aluminum-plastic composite pipes to play a role in large-diameter tap water transportation, which is highly welcomed by users and has become one of the most competitive new products in the pipeline market.
Coated steel pipes are made by coating plastic on the basis of large-diameter spiral welded pipes and high-frequency welded pipes, with a maximum pipe diameter of 1200mm. Various plastic coatings with different properties such as polyvinyl chloride (PVC), polyethylene (PE), epoxy resin (EPOZY) can be applied according to different needs. They have good adhesion, strong corrosion resistance, and can withstand strong acids, alkalis, and other chemical corrosion. They are non-toxic, rust free, wear-resistant, impact resistant, and have strong permeability. The surface of the pipeline is smooth and does not adhere to any substances, which can reduce resistance during transportation, improve flow and transportation efficiency, and reduce pressure loss during transportation. There is no solvent or exudate in the coating, so it will not contaminate the medium being transported, ensuring the purity and hygiene of the fluid. It can be used alternately in the temperature range of -40 ℃ to+80 ℃, without aging or cracking, and can be used in harsh environments such as cold regions.
Large diameter coated steel pipes are widely used in engineering fields such as tap water, natural gas, petroleum, chemical, pharmaceutical, communication, power, and marine.