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Types of Welded Steel Pipes:
Carbon steel welded pipes can be divided into three types according to the weld formation method: Longitudinal submerged arc welded steel pipes (LSAW), Spiral welded steel pipes (SSAW), and Electric resistance welded Steel Pipe (ERW, also called high-frequency straight seam welded steel pipes).
Longitudinal submerged arc steel pipe (LSAW pipe) is a steel pipe with a weld seam parallel to the longitudinal direction of the steel pipe. It is made of hot-rolled or cold-rolled steel plates or steel strips that are curled and welded. The production process of straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is rapid. Straight seam steel pipes are widely used in water supply projects, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, and urban construction.
Spiral welded steel pipe (
SSAW pipe) is made of strip steel coils as raw materials, rolled into tube blanks at a certain spiral angle, and then welded together. It can use narrow strip steel to produce large diameters. steel pipe. Spiral steel pipes are mainly used in drainage and water supply projects, fluid liquid, and solid transportation pipelines. It is widely used in urban construction and municipal engineering.
The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. Welded pipes with larger diameters can be produced from narrower billets, and welded pipes with different diameters can also be produced from billets of the same width. However, compared with straight seam pipes of the same length, the weld length is increased by 30~100%, and the production speed is lower.
Electric resistance welded steel pipe (ERW pipe) uses the skin effect and proximity effect of high-frequency current to heat and melt the edge of the pipe blank after the hot rolled coil is formed by a forming machine, and presses it under the action of a squeeze roller Welding to achieve production. ERW has the characteristics of high efficiency,low cost,material saving and easy automation,it is widely used in aviation, aerospace, energy, electronics, automotive, light industry and other industrial sectors, is an important link in the welding process.
Advantages and disadvantages of welded steel pipes:
Advantages of welded steel pipes:
1. High efficiency and energy saving
The welding process of welded steel pipes uses advanced welding technology and materials, which results in high welding efficiency and low energy consumption. Compared with traditional pipes, it can greatly reduce costs and energy consumption. In addition, the specifications and length of welded steel pipes can be customized as needed, making them more convenient in transportation and installation.
2. Excellent mechanical properties
Welded steel pipes have thicker walls, higher strength and stiffness, and can withstand greater pressure and impact. At the same time, due to its excellent mechanical properties, welded steel pipes can be used in various complex terrains and environments, such as mountains, rivers, bridges, etc.
3. Good corrosion resistance
Welded steel pipes are specially treated and have better corrosion resistance. In corrosive media such as acids, alkalis, and salts, welded steel pipes can operate stably for a long time, ensuring the safety and service life of the pipeline.
4. Good pressure resistance
Another important advantage of welded steel pipe is its excellent pressure resistance. The use of welding technology makes the wall of the steel pipe uniform and dense, which can effectively improve the pressure resistance of the steel pipe and enable it to withstand greater internal pressure. Therefore, welded steel pipe is an indispensable pipeline material in some occasions that require high pressure resistance of pipelines, such as petroleum, natural gas, chemical industry and other fields.
5. High strength
Welded steel pipes use high-temperature fusion welding technology, which can effectively improve the strength and hardness of the pipe. The welded steel pipe not only has excellent strength and stiffness, but also can withstand greater pressure and load. Therefore, welded steel pipes are widely used in some situations that require high strength and stiffness of pipes, such as large machinery manufacturing, shipbuilding, pressure vessels and other fields.
6. Stable quality
Because welded steel pipes adopt a series of precise production processes and quality control measures, their quality is stable and reliable. In particular, the welding process adopts automated production technology, which greatly improves the quality stability of steel pipes, avoids many problems caused by different technical levels of workers or poor welding joint quality in manual welding, and ensures the quality of steel pipes and welding quality.
7. Convenient construction
Another advantage of welded steel pipes is that they are easy to construct and can quickly complete the pipe welding work and improve construction efficiency. Compared with traditional cast pipes, welded steel pipes have a more flexible construction method and can be cut and spliced as needed, making them suitable for various occasions.
8. Environmental protection and health
During the production and use of welded steel pipes, no harmful substances and odors will be produced. At the same time, due to its good corrosion resistance, it can reduce the cleaning and maintenance work of pipelines and reduce the impact on the environment.
9. Reusable
Welded steel pipes have thicker walls and can be reused multiple times after inspection and treatment. This not only reduces costs, but also reduces resource waste and environmental pollution.
10. Wide range of application
Welded steel pipes are suitable for various fields and industries, such as construction, petroleum, chemical industry, light industry, machinery, etc. Its excellent mechanical properties and corrosion resistance enable it to operate stably in a variety of environments.
Disadvantages of welded steel pipe: Seamlsss VS Welded Pipe
During the welding manufacturing process, if the welding technology is not up to standard, the joints may have problems such as incomplete penetration and unsealed welds, which may lead to water leakage, air leakage, etc. after welded pipe construction.
Because the surface of the welded pipe does not receive special anti-corrosion treatment, if it encounters high humidity, high oxides and other environments during use, it is easy to cause rust and wear on the surface of the welded pipe. Compared with
seamless steel tubes, the welds of straight seam welded pipes are more susceptible to corrosion by chemical substances. During use, if harmful substances such as strong acids and alkalis are encountered, the metal structure at the weld may be corroded, resulting in pipeline failure, rupture, leakage and other safety issues.
Since the production process of straight seam welded pipes requires multiple processes such as billet curling, cold bending, and heat straightening, it is difficult to guarantee the surface quality of the pipes. For example, unevenness in the welding joint, residual moisture, grease and other impurities will adversely affect the performance and service life of the pipeline.
There is a certain degree of stress concentration in the internal welds of straight seam welded pipes, but seamless steel pipes do not have this defect. This makes the straight seam welded pipe have limited pressure resistance under harsh conditions such as high temperature and high pressure, and is prone to cracks, deformation and other problems.
5. Poor dimensional accuracy
Due to the influence of the production process, the dimensional accuracy of straight seam welded pipes is often worse than that of seamless steel pipes. In some situations, such as applications that require high-precision processing and high sealing performance, straight seam welded pipes may not be suitable.
The main uses and applications of welded steel pipes are as follows:
1. Conveying pipelines
Welded steel pipes are widely used to transport oil, natural gas, gas, water and other fluids, especially in urban gas and water supply systems.
2. Structural pipe
Welded steel pipes are used in engineering fields such as building structures, bridges, steel frames, and supports. They have good bearing capacity and shock resistance.
3. Electric power industry
Welded pipes are also suitable for transportation pipelines in the electric power industry. Among them, high voltage power transmission and gas transmission, low voltage power distribution and gas transmission, underground gas pipeline, heat pipeline, urban gas pipeline and other places are also commonly used welded pipe as a conveying pipeline materials.
4. Machinery manufacturing
Contact us to discuss your requirements of Longitudinal Welded Pipe. Our experienced sales team can help you identify the options that best suit your needs.
Welded steel pipes can be used to manufacture various mechanical parts, such as shafts, brackets, conveyor rollers, etc.
5. Oil and gas drilling
Welded steel pipes can be used in the manufacture of oil and gas drilling and oil production equipment, such as drill pipes, casings, etc.
6. Tower Fabrication: Welded steel pipes are used in the fabrication of broadcasting and communication towers.
7. Greenhouses: Welded steel pipes are often used in the manufacture of supports for greenhouses due to their lower cost and better strength.
8. Bicycle and motorcycle manufacturing: Welded steel pipes are used to make the frames of bicycles and motorcycles.
9. Furniture manufacturing: Welded steel pipes can be used to produce various furniture such as bed frames, bookshelves, chairs, etc.
Overall, as a widely used steel pipe, welded pipe has many advantages, including low cost, wide applicability of materials and so on. The above brief description of the welded pipe abbreviation and its application is only one part, they have many other applications and abbreviations, we can further understand and apply in the actual production and use.
Welded steel pipe, also known as welded pipe, is a steel pipe made of steel plate or strip steel after crimping and welding. Welded steel pipe has a simple production process, high production efficiency, many varieties and specifications, and less equipment, but its general strength is lower than that of seamless steel pipes. Welded steel pipes are divided into straight seam welded pipes and spiral welded pipes according to the form of the weld.
The blanks used for welded steel pipes are steel plates or strips, which are divided into furnace welded pipes, electric welded (resistance welded) pipes and automatic arc welded pipes due to their different welding processes. Due to the different welding forms, it is divided into two types: straight seam welded pipe and spiral welded pipe. Because of its end shape, it is divided into circular welded pipe and special-shaped (square, flat, etc.) welded pipe. Welded pipes are divided into the following varieties due to their different materials and uses:
GB/T- (galvanized welded steel pipe for low pressure fluid transportation). Mainly used for conveying general lower pressure fluids such as water, gas, air, oil and heating hot water or steam and other purpose pipes. Its representative material is: Q235A grade steel.
GB/T- (Welded steel pipe for mining fluid transportation). It is mainly used for straight seam welded steel pipes for mine air pressure, drainage and shaft discharge gas. It represents the material Q235A, B grade steel. GB/T- (large diameter electric welded steel pipe for low pressure fluid transportation). Mainly used for conveying low pressure fluids such as water, sewage, gas, air, heating steam and other purposes. It represents the material Q235A grade steel.
GB/T- (stainless steel welded steel pipe for mechanical structure). Mainly used in machinery, automobiles, bicycles, furniture, hotel and restaurant decoration and other mechanical parts and structural parts. Its representative materials are 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
GB/T- (stainless steel welded steel pipe for fluid transportation). Mainly used for conveying low pressure corrosive medium. The representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, Cr17Ni14Mo2, etc.
In addition, welded stainless steel pipes for decoration (GB/T -), stainless steel welded pipes for architectural decoration (JG/T -), large-diameter electric-welded steel pipes for low-pressure fluid transportation (GB/T -), and Welded steel pipes for heat exchangers (YB-).
The production process of the straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is fast. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe. However, compared with the same length of straight seam pipe, the length of the weld is increased by 30~100%, and the production speed is lower.
Therefore, most of the welded pipes with smaller diameters use straight seam welding, and most of the welded pipes with large diameters use spiral welding.
Supplement: The welded pipe is welded with strip steel, so its status is not as high as that of the seamless pipe.
Additional types of welded pipes:
1. Ordinary carbon steel wire casing (GB-88) is a steel pipe used to protect wires in electrical installation projects such as industrial and civil buildings, installation of machinery and equipment.
2. Straight seam electric welded steel pipe (YB242-63) is a steel pipe with the weld seam parallel to the longitudinal direction of the steel pipe. Usually divided into metric electric welded steel pipe, electric welded thin-walled pipe, transformer cooling oil pipe and so on.
3. Spiral seam submerged arc welded steel pipe for pressurized fluid transportation (SY-83) is made of hot-rolled steel coil as a tube blank, spirally formed at constant temperature, and welded by double-sided submerged arc welding. It is used for pressurized fluid transportation. Spiral seam steel pipe. The steel pipe has strong pressure bearing capacity and good welding performance. After various strict scientific inspections and tests, it is safe and reliable to use. The diameter of the steel pipe is large, the transportation efficiency is high, and the investment in laying pipelines can be saved. Mainly used for pipelines for transporting oil and natural gas.
4. Spiral seam high-frequency welded steel pipe for pressurized fluid transportation (SY-83) is made of hot-rolled steel coil as a tube blank, which is spirally formed at constant temperature and welded by high-frequency lap welding method for pressurized fluid transportation. Spiral seam high frequency welded steel pipe. The steel pipe has strong pressure bearing capacity and good plasticity, which is convenient for welding and processing. After various strict and scientific inspections and tests, it is safe and reliable to use. The steel pipe has a large diameter and high transportation efficiency, and can save investment in laying pipelines. Mainly used for laying pipelines for transporting oil, natural gas, etc.
5. Spiral seam submerged arc welded steel pipe (SY-83) for general low-pressure fluid transportation is made of hot-rolled steel coil as the tube blank, which is often spirally formed at high temperature, and is made by double-sided automatic submerged arc welding or single-sided welding. Submerged arc welded steel pipes for general low-pressure fluid transportation such as water, gas, air and steam.
6. Spiral seam high-frequency welded steel pipe (SY-83) for general low-pressure fluid conveying is made of hot-rolled steel coil as a tube blank, which is spirally formed at constant temperature, and is welded by high-frequency lap welding for general low-pressure fluid conveying. Seam high frequency welded steel pipe.
7. Spiral-welded steel pipe for piles (SY-83) is made of hot-rolled steel coils as tube blanks, which are often spirally formed at high temperature, and are made by double-sided submerged arc welding or high-frequency welding. They are used for civil construction structures, docks, bridges Equal foundation pile
By use
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.
General 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 can be divided into two types: ordinary steel pipe and thickened steel pipe according to the specified wall thickness.
Galvanized steel pipes: In order to improve the corrosion resistance of steel pipes, general steel pipes (black pipes) are 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.
Oxygen blowing welded pipe: It is used as oxygen blowing pipe for steel making, generally small-diameter welded steel pipe, with eight specifications ranging from 3/8 inch to 2 inch. Made with 08, 10, 15, 20 or Q195-Q235 steel strip. In order to prevent corrosion, some are aluminized.
Wire casing: It is also an ordinary carbon steel electric welded steel pipe, which is used in concrete and various structural power distribution projects. The commonly used nominal diameter is 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.
Metric welded pipe: The specification is in the form of a seamless pipe, and the welded pipe is expressed in millimeters of outer diameter * wall thickness. It is welded with the hot and cold strips of ordinary carbon steel, high-quality carbon steel or general low-alloy steel, or after welding with hot strips. And then made by cold-dial 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.
Roller 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.
Transformer 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.
Special-shaped pipes: square pipes, rectangular pipes, hat-shaped pipes, and hollow rubber steel doors and windows welded by ordinary carbon structural steel and 16Mn steel strips, mainly used for agricultural machinery components, steel windows and doors, etc.
Electric welding thin-walled tube: mainly used to make 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.
Spiral welded pipe: It is made by rolling low carbon carbon structural steel or low alloy structural steel strip at a certain helix angle (called forming angle) into a tube blank, and then welding the pipe seams. Strip steel produces 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.
According to the shape of the end, it is divided into circular welded pipe and special-shaped (square, flat, etc.) welded pipe.