Features of precision seamless steel pipe:
1. High precision, saving the loss when machining the user's materials.
2. There are many specifications and a wide range of applications.
3. The cold rolled product has high precision, good surface quality and good straightness.
4. The inner diameter of the steel pipe can be made into a hexagon.
5. The performance of the steel pipe is superior and the metal is relatively dense.
Advantages of precision seamless steel pipe:
Compared with solid steel such as round steel, seamless steel pipe has a light weight when it has the same bending and torsional strength. It is an economical section steel and is widely used in the manufacture of structural parts and mechanical parts. Precision steel pipes also have their own characteristics while inheriting the advantages of seamless steel pipes. Precision manufacturing of ring parts can improve material utilization, simplify manufacturing processes, save materials and processing man-hours, such as rolling bearing rings, jacks, etc., and have been widely used in precision steel pipes.
The promotion and application of precision seamless pipes is of great significance for saving steel, improving processing efficiency, reducing processing steps or equipment investment, saving cost and processing time, increasing production volume and material utilization rate, and helping to improve product quality and reduce costs. It is of great significance to improve economic efficiency. Generally, precision seamless pipes are used in industries with high precision requirements, and seamless pipes are mostly used without precision requirements. After all, the price of precision seamless pipes of the same specification is higher than that of seamless pipes.
http://www.xysteelpipe.com/info/Characteristics-and-advantages-of-precision-seamless-tubes-1282-1.htm
2018年11月29日星期四
2018年11月28日星期三
Technical requirements for ERW steel pipe
With its special technical production process, ERW steel pipe can be applied in various qualities, wall thicknesses, and diameters of the finished pipes. This would be the contribution of the technical technology. Today, we will discuss the technical requirements of this kind of tube mainly.
Yield strength would have the customized range. For ERW steel pipe, we would control it higher than the J55 up to 173 ~ 206 MPa.
If your tube products under the same size, orientation, minimum size, then we will figure out that relative products can absorb lower than N80 steel grade.
Of course, for the nondestructive testing methods of seamless pipe, coupling stock, welded steel pipe like ERW one would be different from them.
Of course, the color would be different due to the technical requirement’s difference.
http://www.xysteelpipe.com/info/Technical-requirements-for-ERW-steel-pipe-1280-1.htm
Yield strength would have the customized range. For ERW steel pipe, we would control it higher than the J55 up to 173 ~ 206 MPa.
If your tube products under the same size, orientation, minimum size, then we will figure out that relative products can absorb lower than N80 steel grade.
Of course, for the nondestructive testing methods of seamless pipe, coupling stock, welded steel pipe like ERW one would be different from them.
Of course, the color would be different due to the technical requirement’s difference.
http://www.xysteelpipe.com/info/Technical-requirements-for-ERW-steel-pipe-1280-1.htm
Thick wall seamless steel tube knowledg
The thick-walled seamless steel pipe production line is characterized by long production line, many transmission equipment, strict tension control requirements, easy deviation of the strip, and continuous production. During the finish rolling process, the local area enters the upper limit of the non-recrystallization zone and the two-phase zone of the austenitic seamless steel pipe manufacturer in advance. The size and uniformity of the ferrite grains obtained by rolling in the non-recrystallization zone are related to the total deformation amount and the pass reduction rate at the rolling stage.
When the total deformation amount and the pass reduction ratio are larger, the ferrite is obtained. The finer and evener the body grains. The local area, that is, the crack opening and the middle part thereof, enters earlier than the base side due to supercooling, so the ferrite grains of the crack at the opening are finer, the grain size of the matrix is ??not changed much, and the difference between the two causes the rolling crack. .
The continuous hot-dip galvanizing production line of thick-walled seamless steel pipe is divided into three parts: the inlet section, the process section and the inlet section according to the production process. The function of the inlet section is 45# seamless steel pipe to ensure the continuous feeding of the steel strip in the process section. The main equipments include unwinding machine, welding machine, 1#S roll and inlet looper; the process section equipment has 2#S roll, furnace roll, furnace tweezers, zinc pots, air knives, 3#S rolls, this section requires thick-walled seamless steel tubes to run at a constant speed, the galvanized layer is thin and uniform; the inlet section is to roll the zinc-plated steel strip into coils and ensure Continuous production, the main equipment is the inlet looper, 4#S roller, roll front pinch roller, coiler and so on.
At the same time it is also the best choice for liquid transport steel pipes, but as time goes on, the probability of steel pipe damage is also very high. At this time, the role of thick-walled seamless steel pipes became apparent. Thick-walled seamless steel pipe is the main pipe used to transport liquids today. Its strength is higher than that of ordinary steel pipes, corrosion resistance is also enhanced, and the service life is increased by ten times.
In addition, it is the main material for making the drive shaft on the car. After all, the strength of the thick-walled seamless steel pipe is very high, and the manufactured transmission shaft will not be easily deformed, which can completely ensure the safety of driving. It can be seen that the help of thick-walled seamless steel pipes for our lives is also very large.
http://www.xysteelpipe.com/info/Thick-wall-seamless-steel-tube-knowledge-1281-1.htm
When the total deformation amount and the pass reduction ratio are larger, the ferrite is obtained. The finer and evener the body grains. The local area, that is, the crack opening and the middle part thereof, enters earlier than the base side due to supercooling, so the ferrite grains of the crack at the opening are finer, the grain size of the matrix is ??not changed much, and the difference between the two causes the rolling crack. .
The continuous hot-dip galvanizing production line of thick-walled seamless steel pipe is divided into three parts: the inlet section, the process section and the inlet section according to the production process. The function of the inlet section is 45# seamless steel pipe to ensure the continuous feeding of the steel strip in the process section. The main equipments include unwinding machine, welding machine, 1#S roll and inlet looper; the process section equipment has 2#S roll, furnace roll, furnace tweezers, zinc pots, air knives, 3#S rolls, this section requires thick-walled seamless steel tubes to run at a constant speed, the galvanized layer is thin and uniform; the inlet section is to roll the zinc-plated steel strip into coils and ensure Continuous production, the main equipment is the inlet looper, 4#S roller, roll front pinch roller, coiler and so on.
At the same time it is also the best choice for liquid transport steel pipes, but as time goes on, the probability of steel pipe damage is also very high. At this time, the role of thick-walled seamless steel pipes became apparent. Thick-walled seamless steel pipe is the main pipe used to transport liquids today. Its strength is higher than that of ordinary steel pipes, corrosion resistance is also enhanced, and the service life is increased by ten times.
In addition, it is the main material for making the drive shaft on the car. After all, the strength of the thick-walled seamless steel pipe is very high, and the manufactured transmission shaft will not be easily deformed, which can completely ensure the safety of driving. It can be seen that the help of thick-walled seamless steel pipes for our lives is also very large.
http://www.xysteelpipe.com/info/Thick-wall-seamless-steel-tube-knowledge-1281-1.htm
2018年11月25日星期日
LSAW steel pipe production process
LSAW steel pipe is a longitudinally parallel steel pipe. Usually divided into metric welded steel pipe, welded thin-walled pipe, transformer cooling oil pipe and so on. The straight seam welded pipe has a simple production process, high production efficiency, low cost, and rapid development. LSAW steel pipe according to the production process can be divided into high-frequency straight seam steel pipe and submerged arc welded straight seam steel pipe. Submerged arc welded straight seam steel pipes are divided into UOE, RBE, and JCOE steel pipes according to their different forming methods. The following describes the most common high-frequency straight seam steel pipe and submerged arc welded straight seam steel pipe forming process.
1. Striking: After the steel plate used for manufacturing large-diameter submerged-arc welded straight-joint steel pipes enters the production line, full-plate ultrasonic inspection is first performed;
2. Milling edge: Through the edge milling machine, the two edges of the steel plate are double-sided milled to achieve the required plate width, plate edge parallelism and groove shape;
3. Pre-bend: Pre-bending machine for pre-bending the edge so that the edge of the board has a curvature that meets the requirements;
4. Forming: Firstly, half of the pre-bent steel plate is stamped and stamped into a "J" shape on a JCO forming machine. The other half of the steel plate is also bent and pressed into a "C" shape to form an opening. The "O" shape
5. Pre-welding: After the formation of straight seam welded steel pipe joints and continuous welding using gas shielded welding (MAG);
6. Internal welding: Use vertical multi-wire submerged arc welding (up to four wires) to weld inside the straight seam steel pipe;
7. Outer welding: Use vertical multi-wire submerged arc welding to weld outside LSAW steel pipe;
8. Ultrasonic inspection I: 100% inspection of the internal and external welds of the longitudinal welded steel pipe and the base metal on both sides of the weld;
9. X-ray inspection I: 100% X-ray industrial television inspection of the inner and outer welds, using image processing systems to ensure the detection sensitivity;
10. Expanded diameter: The full-length of the submerged-arc welded straight seam steel pipe is expanded to improve the dimensional accuracy of the steel pipe, and the distribution of the internal stress of the steel pipe is improved;
11. Hydraulic pressure test: The root diameter of the expanded steel pipe is tested on the hydrostatic testing machine to ensure that the steel pipe meets the required test pressure. The machine has automatic recording and storage functions;
12. Chamfering: After passing the inspection, the steel pipe is processed by the pipe end to reach the required pipe end groove size;
13. Ultrasonic inspection II: Ultrasonic inspection is performed one by one again to check for defects that may occur in straight seam welded steel pipes after diameter expansion and water pressure.
14. X-ray examination II: X-ray industrial television inspection and tube-end weld seam examination of steel tubes after diameter expansion and hydrostatic pressure testing;
15. Tube end magnetic particle inspection: This inspection is performed to find the tube end defects;
16. Anti-corrosion and coating: The qualified steel pipe is anti-corrosion and coating according to the user's requirements.
1. Striking: After the steel plate used for manufacturing large-diameter submerged-arc welded straight-joint steel pipes enters the production line, full-plate ultrasonic inspection is first performed;
2. Milling edge: Through the edge milling machine, the two edges of the steel plate are double-sided milled to achieve the required plate width, plate edge parallelism and groove shape;
3. Pre-bend: Pre-bending machine for pre-bending the edge so that the edge of the board has a curvature that meets the requirements;
4. Forming: Firstly, half of the pre-bent steel plate is stamped and stamped into a "J" shape on a JCO forming machine. The other half of the steel plate is also bent and pressed into a "C" shape to form an opening. The "O" shape
5. Pre-welding: After the formation of straight seam welded steel pipe joints and continuous welding using gas shielded welding (MAG);
6. Internal welding: Use vertical multi-wire submerged arc welding (up to four wires) to weld inside the straight seam steel pipe;
7. Outer welding: Use vertical multi-wire submerged arc welding to weld outside LSAW steel pipe;
8. Ultrasonic inspection I: 100% inspection of the internal and external welds of the longitudinal welded steel pipe and the base metal on both sides of the weld;
9. X-ray inspection I: 100% X-ray industrial television inspection of the inner and outer welds, using image processing systems to ensure the detection sensitivity;
10. Expanded diameter: The full-length of the submerged-arc welded straight seam steel pipe is expanded to improve the dimensional accuracy of the steel pipe, and the distribution of the internal stress of the steel pipe is improved;
11. Hydraulic pressure test: The root diameter of the expanded steel pipe is tested on the hydrostatic testing machine to ensure that the steel pipe meets the required test pressure. The machine has automatic recording and storage functions;
12. Chamfering: After passing the inspection, the steel pipe is processed by the pipe end to reach the required pipe end groove size;
13. Ultrasonic inspection II: Ultrasonic inspection is performed one by one again to check for defects that may occur in straight seam welded steel pipes after diameter expansion and water pressure.
14. X-ray examination II: X-ray industrial television inspection and tube-end weld seam examination of steel tubes after diameter expansion and hydrostatic pressure testing;
15. Tube end magnetic particle inspection: This inspection is performed to find the tube end defects;
16. Anti-corrosion and coating: The qualified steel pipe is anti-corrosion and coating according to the user's requirements.
SSAW steel pipe technology
Production process of ssaw steel pipe: based on strip coil as raw material, often warm extrusion molding, automatic double-wire double-sided submerged arc welding process welding spiral seam steel pipe.
(1) Raw materials are steel coils, welding wire, and flux. Have to go through rigorous physical and chemical tests before investing.
(2) For the butt-end welding of steel strips, single-wire or double-wire submerged arc welding is used, and after the coils are made into steel pipes, automatic submerged arc welding is used to make up the welding.
(3) Before forming, the steel strip is leveled, trimmed, edged, surface cleaned and pre-flanged.
(4) The electric contact pressure gauge is used to control the pressure of the compression cylinders on both sides of the conveyor to ensure the smooth delivery of the strip.
(5) External control or internal control roll forming.
(6) The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment, and the weld gap are all strictly controlled.
(7) The inner and outer welds are all welded by single-wire or double-wire submerged arc welding using the Lincoln Electric Welder of the United States, thereby obtaining a stable welding specification.
(8) Welded welds were all inspected by an online continuous ultrasonic automatic flaw tester to ensure non-destructive testing coverage of 100% spiral welds. If there are defects, they will be automatically alarmed and painted. The production workers will adjust the process parameters at any time to eliminate defects in time.
(9) Using an air plasma cutter to cut the steel pipe into single pieces.
(10) After cutting into a single steel pipe, a strict first inspection system shall be carried out for each of the first three pipes of each batch to inspect the mechanical properties, chemical composition, fusion condition, surface quality of steel pipes, and non-destructive testing to ensure the pipe-making process. Qualified before they can officially put into production.
(11) Where there is a continuous sound wave flaw detection mark on the weld, after manual ultrasonic and X-ray review, if there is a defect, after repair, it shall undergo a non-destructive test again until it is confirmed that the defect has been eliminated.
(12) The butt joints of the butt welds and the intersections with the spiral welds of the steel strip are all examined by X-ray television or film.
(13) Each pipe is hydrostatically tested and the pressure is radial sealed. The test pressure and time are strictly controlled by the steel pipe hydraulic pressure testing device. Test parameters are automatically printed and recorded.
(14) End-of-pipe machining is performed so that the verticality of the end face, the groove angle and the blunt edge are accurately controlled.
(1) Raw materials are steel coils, welding wire, and flux. Have to go through rigorous physical and chemical tests before investing.
(2) For the butt-end welding of steel strips, single-wire or double-wire submerged arc welding is used, and after the coils are made into steel pipes, automatic submerged arc welding is used to make up the welding.
(3) Before forming, the steel strip is leveled, trimmed, edged, surface cleaned and pre-flanged.
(4) The electric contact pressure gauge is used to control the pressure of the compression cylinders on both sides of the conveyor to ensure the smooth delivery of the strip.
(5) External control or internal control roll forming.
(6) The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment, and the weld gap are all strictly controlled.
(7) The inner and outer welds are all welded by single-wire or double-wire submerged arc welding using the Lincoln Electric Welder of the United States, thereby obtaining a stable welding specification.
(8) Welded welds were all inspected by an online continuous ultrasonic automatic flaw tester to ensure non-destructive testing coverage of 100% spiral welds. If there are defects, they will be automatically alarmed and painted. The production workers will adjust the process parameters at any time to eliminate defects in time.
(9) Using an air plasma cutter to cut the steel pipe into single pieces.
(10) After cutting into a single steel pipe, a strict first inspection system shall be carried out for each of the first three pipes of each batch to inspect the mechanical properties, chemical composition, fusion condition, surface quality of steel pipes, and non-destructive testing to ensure the pipe-making process. Qualified before they can officially put into production.
(11) Where there is a continuous sound wave flaw detection mark on the weld, after manual ultrasonic and X-ray review, if there is a defect, after repair, it shall undergo a non-destructive test again until it is confirmed that the defect has been eliminated.
(12) The butt joints of the butt welds and the intersections with the spiral welds of the steel strip are all examined by X-ray television or film.
(13) Each pipe is hydrostatically tested and the pressure is radial sealed. The test pressure and time are strictly controlled by the steel pipe hydraulic pressure testing device. Test parameters are automatically printed and recorded.
(14) End-of-pipe machining is performed so that the verticality of the end face, the groove angle and the blunt edge are accurately controlled.
LSAW Steel Pipe vs SSAW Steel Pipe
1, Difference between lsaw steel pipe and ssaw steel pipe in production process
LSAW steel pipe is a longitudinally parallel steel pipe. Usually divided into metric welded steel pipe, welded thin-walled pipe, transformer cooling oil pipe and so on. The straight seam welded pipe has a simple production process, high production efficiency, low cost, and rapid development. SSAW steel pipe is a coiled steel pipe made from strip coils as the raw material, which is often warm extruded and welded by an automatic double wire double-sided submerged arc welding process.
The strength of the ssaw steel pipe is generally higher than that of the lsaw steel 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. During the forming process, the steel plate is uniformly deformed, the residual stress is small, and the surface is free of scratches. The processed spiral steel pipe has greater flexibility in the range of diameters and wall thicknesses, especially in the production of high-grade thick-walled pipes, especially small- and medium-caliber thick-walled pipes, which have unparalleled advantages over other technologies and can satisfy users. More requirements on the specifications of spiral steel pipe. The use of advanced double-sided submerged arc welding technology can achieve welding in the best position. It is not prone to defects such as misalignment, welding deviation and incomplete penetration, and it is easy to control the welding quality. 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.
2, Difference between lsaw steel pipe and ssaw steel pipe in security analysis
LSAW steel pipe is mainly subjected to residual stress caused by inhomogeneous cooling. Residual stress is the stress of internal self-phase equilibrium under no external force. Hot rolled section steel of various sections has such residual stress. The larger the section size of general steel, the greater the residual stress is. Although the residual stress is self-balanced, it still has certain influence on the performance of steel components under external forces. For example, it may have adverse effects on deformation, stability, and fatigue resistance; after welding, The non-metallic inclusions inside the straight seam steel pipe are pressed into thin slices, and the delamination phenomenon occurs. The delamination weakens the performance of the straight seam steel pipe in the thickness direction, and there is a possibility of interlayer tearing when the weld seam shrinks. The local strain induced by weld shrinkage often reaches several times of the yield point strain, which is much larger than the strain caused by the load. In addition, the lsaw steel pipe will inevitably have many T-welds, so the probability of welding defects is also greatly improved. Moreover, the welding residual stress at the T-weld is large, and the weld metal is often in a three-dimensional stress state, increasing the possibility of cracking.
SSAW steel pipe with spiral weld distribution, long weld, especially in the dynamic conditions of welding, the weld is too late to leave the molding point of cooling, easy to produce welding hot cracks. The direction of the crack is parallel to the weld and is at a certain angle to the axis of the steel tube, typically between 30-70°. This angle is just in line with the shear failure angle, so its bending, tensile, compressive and torsional resistance is far inferior to the LSAW pipe. At the same time, due to the limitation of the welding position, the resulting saddle shape and ridge-shaped welding seam influence Beautiful. In addition, during the construction process, the intersecting line welds at the spiral welded parent pipe joints split the spiral joints and generate larger welding stress, which greatly weakens the safety performance of the components. Therefore, the non-destructive testing of the spiral welded pipe joints should be strengthened. Ensure welding quality, otherwise spiral submerged arc welded pipe should not be used in important steel structure occasions.
3, Difference between lsaw steel pipe and ssaw steel pipe in the scope of application
LSAW pipe adopts double-side submerged arc welding process. Welding under static conditions, the quality of the weld is high, the weld is short, and the probability of defects is very small. The steel pipe expands through full-length, has a good pipe shape, and is precise in size. The steel pipe has a wide wall thickness range and a wide range of pipe diameters. It is suitable for supporting columns, ultra-large span building structures, such as buildings, bridges, dams, and offshore platforms, as well as wind-resistant and earthquake-resistant structures. Pole mast structure. Spiral steel pipe is a kind of steel commonly used in industry, construction and other industries. Mainly used in tap water projects, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction.
In summary, we can see that the two different types of welded seam pipes have their own characteristics and have different advantages according to different applications.
LSAW steel pipe is a longitudinally parallel steel pipe. Usually divided into metric welded steel pipe, welded thin-walled pipe, transformer cooling oil pipe and so on. The straight seam welded pipe has a simple production process, high production efficiency, low cost, and rapid development. SSAW steel pipe is a coiled steel pipe made from strip coils as the raw material, which is often warm extruded and welded by an automatic double wire double-sided submerged arc welding process.
The strength of the ssaw steel pipe is generally higher than that of the lsaw steel 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. During the forming process, the steel plate is uniformly deformed, the residual stress is small, and the surface is free of scratches. The processed spiral steel pipe has greater flexibility in the range of diameters and wall thicknesses, especially in the production of high-grade thick-walled pipes, especially small- and medium-caliber thick-walled pipes, which have unparalleled advantages over other technologies and can satisfy users. More requirements on the specifications of spiral steel pipe. The use of advanced double-sided submerged arc welding technology can achieve welding in the best position. It is not prone to defects such as misalignment, welding deviation and incomplete penetration, and it is easy to control the welding quality. 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.
2, Difference between lsaw steel pipe and ssaw steel pipe in security analysis
LSAW steel pipe is mainly subjected to residual stress caused by inhomogeneous cooling. Residual stress is the stress of internal self-phase equilibrium under no external force. Hot rolled section steel of various sections has such residual stress. The larger the section size of general steel, the greater the residual stress is. Although the residual stress is self-balanced, it still has certain influence on the performance of steel components under external forces. For example, it may have adverse effects on deformation, stability, and fatigue resistance; after welding, The non-metallic inclusions inside the straight seam steel pipe are pressed into thin slices, and the delamination phenomenon occurs. The delamination weakens the performance of the straight seam steel pipe in the thickness direction, and there is a possibility of interlayer tearing when the weld seam shrinks. The local strain induced by weld shrinkage often reaches several times of the yield point strain, which is much larger than the strain caused by the load. In addition, the lsaw steel pipe will inevitably have many T-welds, so the probability of welding defects is also greatly improved. Moreover, the welding residual stress at the T-weld is large, and the weld metal is often in a three-dimensional stress state, increasing the possibility of cracking.
SSAW steel pipe with spiral weld distribution, long weld, especially in the dynamic conditions of welding, the weld is too late to leave the molding point of cooling, easy to produce welding hot cracks. The direction of the crack is parallel to the weld and is at a certain angle to the axis of the steel tube, typically between 30-70°. This angle is just in line with the shear failure angle, so its bending, tensile, compressive and torsional resistance is far inferior to the LSAW pipe. At the same time, due to the limitation of the welding position, the resulting saddle shape and ridge-shaped welding seam influence Beautiful. In addition, during the construction process, the intersecting line welds at the spiral welded parent pipe joints split the spiral joints and generate larger welding stress, which greatly weakens the safety performance of the components. Therefore, the non-destructive testing of the spiral welded pipe joints should be strengthened. Ensure welding quality, otherwise spiral submerged arc welded pipe should not be used in important steel structure occasions.
3, Difference between lsaw steel pipe and ssaw steel pipe in the scope of application
LSAW pipe adopts double-side submerged arc welding process. Welding under static conditions, the quality of the weld is high, the weld is short, and the probability of defects is very small. The steel pipe expands through full-length, has a good pipe shape, and is precise in size. The steel pipe has a wide wall thickness range and a wide range of pipe diameters. It is suitable for supporting columns, ultra-large span building structures, such as buildings, bridges, dams, and offshore platforms, as well as wind-resistant and earthquake-resistant structures. Pole mast structure. Spiral steel pipe is a kind of steel commonly used in industry, construction and other industries. Mainly used in tap water projects, petrochemical industry, chemical industry, power industry, agricultural irrigation, urban construction.
In summary, we can see that the two different types of welded seam pipes have their own characteristics and have different advantages according to different applications.
Uses of Casing Coupling
The casing is mainly used to support the wellbore during and after drilling to ensure the normal operation of the entire oil well after the drilling process is completed. Different types of casing used in oil production: The surface oil casing is used to protect the well from contamination by shallow water and shallow gas layers and to support the wellhead equipment and maintain the other layers of the casing. Technical casing is used to separate the pressures at different levels so that the drilling fluid can be circulated and the production casing can be protected.
In order to install anti-blasting devices, leak-proof devices and tail pipes in wells. Oil reservoir casing drains oil and natural gas from the reservoir beneath the surface and is used to protect the well and stratify the drilling mud. When the oil casing is produced, the outer diameter is usually 114.3 mm to 508 mm. Domestic casing according to SY/T 6194-96 regulations, casing length is not fixed, its range of 8-13m. But no less than 6m can be provided, the number of which must not exceed 20%.
The inner and outer surfaces of the sleeve must not have folds, hair lines, separations, cracks, folds, and scabs. These defects should be completely removed, and the depth of removal should not exceed 12.5% of the nominal wall thickness. Couplings shall not have defects such as folds, hairline, separation, cracks, pleats, and scabs on the outer surface of the coupling. The surface of the threads of the casing and coupling should be smooth. No burrs, tears, and enough breakage of the threads will affect the strength and other defects of the tight connection.
In order to install anti-blasting devices, leak-proof devices and tail pipes in wells. Oil reservoir casing drains oil and natural gas from the reservoir beneath the surface and is used to protect the well and stratify the drilling mud. When the oil casing is produced, the outer diameter is usually 114.3 mm to 508 mm. Domestic casing according to SY/T 6194-96 regulations, casing length is not fixed, its range of 8-13m. But no less than 6m can be provided, the number of which must not exceed 20%.
The inner and outer surfaces of the sleeve must not have folds, hair lines, separations, cracks, folds, and scabs. These defects should be completely removed, and the depth of removal should not exceed 12.5% of the nominal wall thickness. Couplings shall not have defects such as folds, hairline, separation, cracks, pleats, and scabs on the outer surface of the coupling. The surface of the threads of the casing and coupling should be smooth. No burrs, tears, and enough breakage of the threads will affect the strength and other defects of the tight connection.
Hydrostatic Pressure Test Casing Pipe
The hydrostatic pressure test of casing pipe is an indispensable part of the production process of the steel pipe. Its role is to test the anti-leakage performance of the steel pipe under standard test pressure and regulation time. Like radiographs, ultrasonics, and other flaw detection techniques, it is an important means of testing the overall quality of steel tubes.
The popular description is to fill the pipe with water and test its ability to maintain the specified pressure without leaking or breaking under pressure. Its operations include three steps: flushing, pressure testing and water control.
API-5CT standard for hydrostatic pressure test
1. The hydrostatic pressure test value of coupling and threaded pipe is the lowest value of the hydrostatic test pressure of the flat end pipe, the maximum hydrostatic pressure test pressure of the coupling, and the internal pressure leakage resistance, but the standard maximum pressure is 69MPa and the pressure is calculated. The value is generally rounded to the nearest 0.5 MPa.
2. According to API requirements, the hydrostatic test pressure measuring device should be calibrated within 4 months before each use.
3. If the customer has special requirements, a higher pressure test pressure can be selected.
4. Hydrostatic pressure test Leakage is the basis for rejection.
5. Except where otherwise agreed between the purchaser and the manufacturer, hydrostatic pressure testing is not required for coupling blanks, coupling materials, nearby materials, or Q125 steel pup joints.
The popular description is to fill the pipe with water and test its ability to maintain the specified pressure without leaking or breaking under pressure. Its operations include three steps: flushing, pressure testing and water control.
API-5CT standard for hydrostatic pressure test
1. The hydrostatic pressure test value of coupling and threaded pipe is the lowest value of the hydrostatic test pressure of the flat end pipe, the maximum hydrostatic pressure test pressure of the coupling, and the internal pressure leakage resistance, but the standard maximum pressure is 69MPa and the pressure is calculated. The value is generally rounded to the nearest 0.5 MPa.
2. According to API requirements, the hydrostatic test pressure measuring device should be calibrated within 4 months before each use.
3. If the customer has special requirements, a higher pressure test pressure can be selected.
4. Hydrostatic pressure test Leakage is the basis for rejection.
5. Except where otherwise agreed between the purchaser and the manufacturer, hydrostatic pressure testing is not required for coupling blanks, coupling materials, nearby materials, or Q125 steel pup joints.
Heat Treatment Technology of Casing Pipe
27MnCrV steel AC1 = 736 °C, AC3 = 810 °C, sub-temperature quenching heating temperature between 740-810 °C selected. Sub-temperature quenching selection of heating temperature 780 °C, quenching and heating of the holding time 15min; tempering temperature after the selection of 630 °C, tempering heating holding time 50min. Since the sub-temperature quenching is heated in the α+γ two-phase region, quenching is performed in the state where the retained ferrite is partially dissolved, and the toughness is improved while maintaining high strength.
At the same time, the low-temperature quenching is lower than the conventional temperature, reducing the quenching stress, thereby reducing the quenching deformation, thus ensuring the smooth operation of the heat treatment production, and providing a very good raw material for subsequent wire processing and the like.
At present, the process has been applied to the processing plant of Magnon Steel, and the warranty data shows that after heat treatment, the yield strength Rt0.6 of the steel pipe is 820-860MPa, the tensile strength Rm is 910-940MPa, and the impact toughness Akv is 65-85J. , The resistance to destruction is 100% qualified. The data shows that the 27MnCrV steel pipe is a very good high-grade casing pipe, on the other hand, it also shows that the sub-temperature quenching process is an excellent method to avoid high-temperature brittleness in the production of steel products.
At the same time, the low-temperature quenching is lower than the conventional temperature, reducing the quenching stress, thereby reducing the quenching deformation, thus ensuring the smooth operation of the heat treatment production, and providing a very good raw material for subsequent wire processing and the like.
At present, the process has been applied to the processing plant of Magnon Steel, and the warranty data shows that after heat treatment, the yield strength Rt0.6 of the steel pipe is 820-860MPa, the tensile strength Rm is 910-940MPa, and the impact toughness Akv is 65-85J. , The resistance to destruction is 100% qualified. The data shows that the 27MnCrV steel pipe is a very good high-grade casing pipe, on the other hand, it also shows that the sub-temperature quenching process is an excellent method to avoid high-temperature brittleness in the production of steel products.
What are the disadvantages of hot and cold rolling processes for seamless tubes
Hot rolled and cold rolled (dial) seamless tubes
1. The cross-section of the cold-rolled seamless pipe is partially embossed, and then the bearing capacity of the bar can be fully utilized; and the hot-rolled steel does not agree with the section of the section.
2. The causes of residual stress in hot-rolled seamless square tubes and cold-rolled sections are different, so the dispersion on the sections is also very different. The residual stress distribution on the section of the cold-formed thin-walled steel is a tortuous type, and the residual stress distribution on the section of the hot-drawn steel or welded steel is a film type.
3. The freely changing stiffness of hot-rolled steel is higher than that of cold-rolled steel, so the torsional function of hot-rolled steel is better than that of cold-rolled steel. Cold-rolled seamless pipe cold-rolled seamless steel pipe refers to steel that is processed into various types by cold drawing, cold bending, cold drawing and other cold working at normal temperature.
Strengths: fast forming speed, high output value, and no damage to the coating, can be made into a variety of cross-sections to meet the needs of the conditions; cold rolling can cause large plastic deformation of the steel, and then improve the yield of the steel point.
Defect:
1. Although there is no hot plastic shrinkage during the forming process, there is still residual stress in the cross section, which inevitably affects the characteristics of the whole steel and part of the steel;
2. The cold-rolled steel profile is generally an open section, so that the freeness of the section changes less. It is simple to change when it is bent. It is simple to show bending and torsion when pressed, and the torsion resistance is poor.
3. The wall thickness of cold-rolled steel is small, and there is no thickening at the corner of the joint of the plate. The ability to gather loads is weak.
http://www.xysteelpipe.com/info/What-are-the-disadvantages-of-hot-and-cold-rolling-processes-for-seamless-tubes-1279-1.htm
1. The cross-section of the cold-rolled seamless pipe is partially embossed, and then the bearing capacity of the bar can be fully utilized; and the hot-rolled steel does not agree with the section of the section.
2. The causes of residual stress in hot-rolled seamless square tubes and cold-rolled sections are different, so the dispersion on the sections is also very different. The residual stress distribution on the section of the cold-formed thin-walled steel is a tortuous type, and the residual stress distribution on the section of the hot-drawn steel or welded steel is a film type.
3. The freely changing stiffness of hot-rolled steel is higher than that of cold-rolled steel, so the torsional function of hot-rolled steel is better than that of cold-rolled steel. Cold-rolled seamless pipe cold-rolled seamless steel pipe refers to steel that is processed into various types by cold drawing, cold bending, cold drawing and other cold working at normal temperature.
Strengths: fast forming speed, high output value, and no damage to the coating, can be made into a variety of cross-sections to meet the needs of the conditions; cold rolling can cause large plastic deformation of the steel, and then improve the yield of the steel point.
Defect:
1. Although there is no hot plastic shrinkage during the forming process, there is still residual stress in the cross section, which inevitably affects the characteristics of the whole steel and part of the steel;
2. The cold-rolled steel profile is generally an open section, so that the freeness of the section changes less. It is simple to change when it is bent. It is simple to show bending and torsion when pressed, and the torsion resistance is poor.
3. The wall thickness of cold-rolled steel is small, and there is no thickening at the corner of the joint of the plate. The ability to gather loads is weak.
http://www.xysteelpipe.com/info/What-are-the-disadvantages-of-hot-and-cold-rolling-processes-for-seamless-tubes-1279-1.htm
2018年11月15日星期四
How to Bend the Square Tube Bending Machine without Wrinkle
There are some steps about how to bend the square tube bending machine not o be wrinkled:
1. Clamp (clamping) part of the tube must be clamped, if not clamping, it will wrinkle.
2. If the clamping clamp, but also wrinkled, pay attention to the diameter of the mold (round mold) shape, the outer mold should be outside the drum, so that the inner wall of the square tube into a little, so the tube deformation is stable.
3. At the same time pay attention to secondary mold and die diameter distance, not too tight or too loose.
4. Solve the above problems or not, it is necessary to adjust the shape of the core, the use of joint through the core, and adjust the distance of the through the core.
5. Adjust the joint through the core or wrinkled, remember to install wrinkle-free mold, try bending slower, timely adjustment of the core lift length and wrinkle-free mold location.
6. If this still does not work, especially for thin-walled stainless steel square tubes or aluminum square tubes, fine sand may be required to ensure high-quality
1. Clamp (clamping) part of the tube must be clamped, if not clamping, it will wrinkle.
2. If the clamping clamp, but also wrinkled, pay attention to the diameter of the mold (round mold) shape, the outer mold should be outside the drum, so that the inner wall of the square tube into a little, so the tube deformation is stable.
3. At the same time pay attention to secondary mold and die diameter distance, not too tight or too loose.
4. Solve the above problems or not, it is necessary to adjust the shape of the core, the use of joint through the core, and adjust the distance of the through the core.
5. Adjust the joint through the core or wrinkled, remember to install wrinkle-free mold, try bending slower, timely adjustment of the core lift length and wrinkle-free mold location.
6. If this still does not work, especially for thin-walled stainless steel square tubes or aluminum square tubes, fine sand may be required to ensure high-quality
Production Process of Large Diameter Thick-walled Square Tube
Production process of large diameter thick-walled square tube are as follows:
The first step: Raw materials that strip, wire, flux. In the input before going through a rigorous physical and chemical testing.
The second step: The end of the strip butt joint, the use of single or double wire submerged arc welding, rolled into large diameter thick-walled square tube automatic submerged arc welding.
The third step: Before forming, strip through leveling, trimming, planing, surface cleaning and conveying to the bending treatment.
The fourth step: The use of electric contact pressure gauge control conveyor pressure on both sides of the press to ensure a smooth strip delivery.
The five step: The use of external control or roller molding.
The six step: Large-diameter thick-walled square tube weld seam gap control device used to ensure the weld gap to meet the welding requirements, pipe diameter, the wrong side of the amount and weld gap have been strictly controlled.
The seventh step: Large-diameter thick-walled square tube wall welding is divided into internal and external welding, are used by the United States Lincoln welding machine for single-wire or double-wire submerged arc welding to obtain a stable welding specifications.
The eighth step: Weld large-diameter thick-walled square tube welded continuous online ultrasonic testing after injury, to ensure that 100% of the spiral weld non-destructive testing coverage. If there are defects, automatic alarm and spray mark, the production workers so adjust the process parameters at any time, promptly eliminate defects.
The nine step: The air plasma cutting machine will be cut into large single-tube thick-walled square tube.
The first step: Raw materials that strip, wire, flux. In the input before going through a rigorous physical and chemical testing.
The second step: The end of the strip butt joint, the use of single or double wire submerged arc welding, rolled into large diameter thick-walled square tube automatic submerged arc welding.
The third step: Before forming, strip through leveling, trimming, planing, surface cleaning and conveying to the bending treatment.
The fourth step: The use of electric contact pressure gauge control conveyor pressure on both sides of the press to ensure a smooth strip delivery.
The five step: The use of external control or roller molding.
The six step: Large-diameter thick-walled square tube weld seam gap control device used to ensure the weld gap to meet the welding requirements, pipe diameter, the wrong side of the amount and weld gap have been strictly controlled.
The seventh step: Large-diameter thick-walled square tube wall welding is divided into internal and external welding, are used by the United States Lincoln welding machine for single-wire or double-wire submerged arc welding to obtain a stable welding specifications.
The eighth step: Weld large-diameter thick-walled square tube welded continuous online ultrasonic testing after injury, to ensure that 100% of the spiral weld non-destructive testing coverage. If there are defects, automatic alarm and spray mark, the production workers so adjust the process parameters at any time, promptly eliminate defects.
The nine step: The air plasma cutting machine will be cut into large single-tube thick-walled square tube.
Difference between Stainless Steel Seamless Pipe and Carbon Steel Seamless Pipe
The so-called difference between stainless steel seamless pipe and carbon steel seamless pipe, stainless steel and carbon steel mainly refers to the difference in the design rules, that is, the design rules of these two types of steel are not universal.
These differences are summarized as follows: The design rules of stainless steel can not be used for carbon steel because there are 3 fundamental differences between stainless steel and carbon steel:
First, when cold working stainless steel produce work hardening, for example, when bending anisotropy, namely: the horizontal and vertical performance are different. The strength increased by cold working can be utilized, but if the bending area is small compared to the total area and negligible, the increase in strength can improve the safety factor to a certain extent.
Second, the shape of the stress / strain curve is different. The elastic limit of stainless steel is about 50% of the yield stress. The yield stress is lower than the yield stress of medium carbon steel in terms of the minimum specified in the standard.
Third, stainless steel does not yield point, usually ó0.2 that yield stress is considered equivalent.
These differences are summarized as follows: The design rules of stainless steel can not be used for carbon steel because there are 3 fundamental differences between stainless steel and carbon steel:
First, when cold working stainless steel produce work hardening, for example, when bending anisotropy, namely: the horizontal and vertical performance are different. The strength increased by cold working can be utilized, but if the bending area is small compared to the total area and negligible, the increase in strength can improve the safety factor to a certain extent.
Second, the shape of the stress / strain curve is different. The elastic limit of stainless steel is about 50% of the yield stress. The yield stress is lower than the yield stress of medium carbon steel in terms of the minimum specified in the standard.
Third, stainless steel does not yield point, usually ó0.2 that yield stress is considered equivalent.
Reasons for corrosion of 304 stainless steel seamless tube
Metal of 304 stainless steel seamless pipe and oxygen in the atmosphere to react, the appearance will form an oxide film. However, the iron oxide formed on a common carbon steel pipe is continuously oxidized, causing the corrosion to continuously expand, and as a result, pores are formed. Such good stainless steel seamless pipes are damaged. We can use galvanized paint or oxidation-resistant metals such as zinc, nickel and chrome to coat the carbon steel. However, as we expected, this maintenance is only a layer of maintenance film, assuming the maintenance layer is damaged, the steel will begin to be eroded. The corrosion resistance of stainless steel depends on chromium. Chromium is part of the steel composition. When chromium is combined with steel, the type of oxide in the surface changes to a surface oxide similar to pure chromium metal. This tightly adhering chromium-rich oxide maintains the appearance and avoids further oxidation.
Heat treatment process includes heating, insulation, cooling, etc., this is done in order to reduce the deformation of the metal forming process due to hardening and other shortcomings, the processing of deformed pipe back to before processing, so that performance is improved.
Now the most common heat treatment tools, including electric furnace and refire furnace; commonly seen control method is automatic temperature control mode.
Different 304 stainless steel seamless pipe fittings require different heat treatment, and not all the deformation of the tools have to be heat treatment, usually low-carbon steel pipe fittings, the final temperature of not less than 723 ℃, then you can not heat treatment, if below this temperature or above 1000 degrees celsius heat treatment should be carried out.
Heat treatment process includes heating, insulation, cooling, etc., this is done in order to reduce the deformation of the metal forming process due to hardening and other shortcomings, the processing of deformed pipe back to before processing, so that performance is improved.
Now the most common heat treatment tools, including electric furnace and refire furnace; commonly seen control method is automatic temperature control mode.
Different 304 stainless steel seamless pipe fittings require different heat treatment, and not all the deformation of the tools have to be heat treatment, usually low-carbon steel pipe fittings, the final temperature of not less than 723 ℃, then you can not heat treatment, if below this temperature or above 1000 degrees celsius heat treatment should be carried out.
Precautions for welding of 304 stainless steel pipe
Precautions for welding of 304 stainless steel pipe are as follows:
1, The use of vertical external power supply, DC positive polarity (wire connected negative).
2, Generally suitable for the welding of sheet 6mm below, with the appearance of weld appearance, welding deformation of a small amount of features.
3, The protective gas is argon, purity of 99.99%. When the welding current is 50 ~ 50A, argon flow rate is 8 ~ 0L / min, when the current is 50 ~ 250A, argon flow rate is 2 ~ 5L / min.
4, Tungsten protruding from the gas nozzle to the length of 4 ~ 5mm is better, in the fillet welding and other poor shielding is 2 ~ 3mm, deep groove where it is 5 ~ 6mm, the nozzle to the work of the general distance more than 5mm.
5, In order to prevent the emergence of welding pores, weld rust, oil, etc. must be cleaned.
6, The welding arc length, welding ordinary steel, preferably 2 ~ 4mm, and welding stainless steel to ~ 3mm is better, too long, the protection is not good.
7, The docking base, in order to prevent the back of the bottom weld is oxidized, the back also need to implement gas protection.
8, In order to make the argon well protect the welding pool, and to facilitate the welding operation, the tungsten centerline and welding workpieces should generally maintain 80 ~ 85 ° angle, filler wire and workpiece surface angle should be as small as possible, Generally 0 & deg; left and right.
9, Wind and ventilation. Windy areas, be sure to take the measures to block the network, while indoors should take appropriate ventilation measures.
1, The use of vertical external power supply, DC positive polarity (wire connected negative).
2, Generally suitable for the welding of sheet 6mm below, with the appearance of weld appearance, welding deformation of a small amount of features.
3, The protective gas is argon, purity of 99.99%. When the welding current is 50 ~ 50A, argon flow rate is 8 ~ 0L / min, when the current is 50 ~ 250A, argon flow rate is 2 ~ 5L / min.
4, Tungsten protruding from the gas nozzle to the length of 4 ~ 5mm is better, in the fillet welding and other poor shielding is 2 ~ 3mm, deep groove where it is 5 ~ 6mm, the nozzle to the work of the general distance more than 5mm.
5, In order to prevent the emergence of welding pores, weld rust, oil, etc. must be cleaned.
6, The welding arc length, welding ordinary steel, preferably 2 ~ 4mm, and welding stainless steel to ~ 3mm is better, too long, the protection is not good.
7, The docking base, in order to prevent the back of the bottom weld is oxidized, the back also need to implement gas protection.
8, In order to make the argon well protect the welding pool, and to facilitate the welding operation, the tungsten centerline and welding workpieces should generally maintain 80 ~ 85 ° angle, filler wire and workpiece surface angle should be as small as possible, Generally 0 & deg; left and right.
9, Wind and ventilation. Windy areas, be sure to take the measures to block the network, while indoors should take appropriate ventilation measures.
2018年11月5日星期一
Special treatment for large diameter steel pipe
If your customer has affection on large diameter steel pipe, no matter ERW steel pipe or LSAW type, you would figure out the advantages for it. Thus, you will finally figure out the special treatment for large diameter steel pipe.
In order to achieve the standards like API, we know that large diameter pipe would have strict production process. Thus, it can serve on the engineering project like bridge piling, underwater piling, piling high-rise buildings.
With its good adhesion, corrosion resistance, and other traits, we will make large diameter steel tube improve traffic and transportation efficiency, reduce delivery pressure loss.
Coating solvent-free is another character, no leaking substances, and thus will not contaminate the transmission medium, thus ensuring fluid purity and hygiene at -40 ℃ to +80 ℃ range can be used alternately hot and cold cycles, aging, no cracks, which can in cold areas such harsh environments.
In order to achieve the standards like API, we know that large diameter pipe would have strict production process. Thus, it can serve on the engineering project like bridge piling, underwater piling, piling high-rise buildings.
With its good adhesion, corrosion resistance, and other traits, we will make large diameter steel tube improve traffic and transportation efficiency, reduce delivery pressure loss.
Coating solvent-free is another character, no leaking substances, and thus will not contaminate the transmission medium, thus ensuring fluid purity and hygiene at -40 ℃ to +80 ℃ range can be used alternately hot and cold cycles, aging, no cracks, which can in cold areas such harsh environments.
Main steel grade for API 5CT steel pipe
API 5CT steel tube belongs to API casing. No matter seamless steel pipe or welded type, it is mainly used among the structural retainer for the walls of oil, gas wells. Today, our main topic would focus on main steel grade of it.
The main steel grade of API 5CT would conclude the following five types.
API 5CT J55;
API 5CT K55;
API 5CT N80;
API 5CT L80;
API 5CT P110.
With its special characters, we will figure out that the basic size for this steel pipeline.
Outer Dimensions: 6.0mm–219.0mm;
Wall Thickness: 1.0mm–30 mm;
Length: max 12000mm.
The main steel grade of API 5CT would conclude the following five types.
API 5CT J55;
API 5CT K55;
API 5CT N80;
API 5CT L80;
API 5CT P110.
With its special characters, we will figure out that the basic size for this steel pipeline.
Outer Dimensions: 6.0mm–219.0mm;
Wall Thickness: 1.0mm–30 mm;
Length: max 12000mm.
The importance of heat treatment to steel pipe production
We cannot ignore any detail during the steel pipe’s production process as all of them would finally determine the quality of seamless or ERW steel pipe. Today, you can hear the importance of heat treatment for steel pipe production.
It needs a microstructure even for heat treatment’s control that allows abrasion resistant steel to have a high hardness, thus, we can get high quality steel pipe with this material. This is accomplished, in part, by adding the proper alloying elements. Except this one, we still need to focus on the heating and a rapid quenching process to form microstructures such as martensite and bainite which gives the steel the required high hardness values. For more information about the heat treatment, welcome to have a view in our factory.
It needs a microstructure even for heat treatment’s control that allows abrasion resistant steel to have a high hardness, thus, we can get high quality steel pipe with this material. This is accomplished, in part, by adding the proper alloying elements. Except this one, we still need to focus on the heating and a rapid quenching process to form microstructures such as martensite and bainite which gives the steel the required high hardness values. For more information about the heat treatment, welcome to have a view in our factory.
Requirement of rust - proof layer of petroleum steel pipeline
Oil transportation, no matter by seamless steel pipe or welded tubes, has high demand for pipeline itself. Today, the special topic would be focus on demands of the rust layer for oil steel tubes.
The affecting factors for the oil pipeline would conclude transport conditions, long or short distance; open dump time, rust varnish and so on. And how can we ignore the bug during the transportation? This need steel pipes have properties of good construction performance, security, environmental protection, quick drying; bright, transparent film and so on. Thus, we will adopt anti-rust layer with good weather resistance; impact, bumps and impact damage during handling and transport of the oil pipeline, there factor, anti-rust layer should have good impact resistance; the operation of shipping, hot and humid zones, anti-rust layer should have good moisture resistance, salt spray resistance.
The affecting factors for the oil pipeline would conclude transport conditions, long or short distance; open dump time, rust varnish and so on. And how can we ignore the bug during the transportation? This need steel pipes have properties of good construction performance, security, environmental protection, quick drying; bright, transparent film and so on. Thus, we will adopt anti-rust layer with good weather resistance; impact, bumps and impact damage during handling and transport of the oil pipeline, there factor, anti-rust layer should have good impact resistance; the operation of shipping, hot and humid zones, anti-rust layer should have good moisture resistance, salt spray resistance.
Identification Of Seamed Steel Pipes And Seamless Steel Pipes
The steel pipe is divided into two major categories according to the molding method and the manufacturing method. The seamless steel pipe and the welded pipe (the welded pipe is what you call the seamed steel pipe). Seamless steel tubes can be further divided into hot rolled and cold rolled cold drawn tubes. The welded pipe can be further divided into a lsaw steel pipe and a ssaw steel pipe. The seam here does not mean that there are gaps, but the steel pipe has weld marks. After the treatment, the welder is difficult to see.
The two are divided according to the processing form. The seamed steel pipe is generally welded. The seamless steel pipe has two methods of cold drawing and hot drawing. The carbon steel pipe is in terms of material, and the galvanized pipe is the surface of the welded pipe after the production. Galvanized treatment. Popular: the conveyor carrier requires high, such as pressure, environment, maintenance, corrosion, temperature, etc. with seamless steel pipe. For pressure and temperature requirements, there are seam steel pipes, such as domestic water pipes and gas pipes.
The easiest way to identify the two is to look at the look. There are seam steel pipes, there will be a welded straight line, or the surface is polished. There is also straightness, uneven thickness, and it can't be tested. Some tubes with seamless steel pipe are annealed to the weld, eliminating the residual stress of the weld, making the weld equivalent to the base metal, and its pressure range is basically equivalent to that of the seamless pipe. However, some seamless steel pipes which are welded or rolled with the jointed steel pipe are mainly small-sized pipes. These pipes are only seamless pipes in terms of shape, and their essence is not very good. It is a pressure test.
http://www.xysteelpipe.com/info/Identification-Of-Seamed-Steel-Pipes-And-Seamless-Steel-Pipes-1263-1.htm
The two are divided according to the processing form. The seamed steel pipe is generally welded. The seamless steel pipe has two methods of cold drawing and hot drawing. The carbon steel pipe is in terms of material, and the galvanized pipe is the surface of the welded pipe after the production. Galvanized treatment. Popular: the conveyor carrier requires high, such as pressure, environment, maintenance, corrosion, temperature, etc. with seamless steel pipe. For pressure and temperature requirements, there are seam steel pipes, such as domestic water pipes and gas pipes.
The easiest way to identify the two is to look at the look. There are seam steel pipes, there will be a welded straight line, or the surface is polished. There is also straightness, uneven thickness, and it can't be tested. Some tubes with seamless steel pipe are annealed to the weld, eliminating the residual stress of the weld, making the weld equivalent to the base metal, and its pressure range is basically equivalent to that of the seamless pipe. However, some seamless steel pipes which are welded or rolled with the jointed steel pipe are mainly small-sized pipes. These pipes are only seamless pipes in terms of shape, and their essence is not very good. It is a pressure test.
http://www.xysteelpipe.com/info/Identification-Of-Seamed-Steel-Pipes-And-Seamless-Steel-Pipes-1263-1.htm
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