The quality of welded pipe depends on the quality of welding. The quality of welding is not only directly related to the quality of the tube, especially with the design of the forming roll, the forming process, the choice of welding parameters. These factors with the equipment to adjust the state and the rapidly changing, only by visual inspection of welding sparks, shavings and simple flaring state, flattening test and other empirical methods of control, it is difficult to maintain a stable quality.
The shape and width of the weld affected zone are closely related to the welding speed, temperature, extrusion force and even tube thickness. When the welding speed constant, the heat affected zone width and welding temperature is proportional to (ie, the higher the temperature, the width of the larger), and inversely proportional to the extrusion force (ie, the greater the extrusion pressure, the smaller the width); when squeeze (Ie, the higher the temperature, the greater the width), and inversely proportional to the welding speed (that is, the faster the faster the width of the smaller); when the welding temperature does not change, the heat-affected zone width is proportional to the welding temperature, The width of the heat-affected zone is inversely proportional to the extrusion force (ie, the larger the squeezing force and the smaller the width), and is inversely proportional to the welding speed (ie, the faster the width and the smaller the width). Thus, the welding process should be welded within the scope of safety, fully explore the potential of pipe equipment, according to the wall thickness of the tube, the rational allocation of induction coil position and the size of the opening angle to ensure adequate heat output conditions, and gradually increase the welding Speed, the appropriate extrusion force to make the formation of the ideal heat affected zone shape, and in this state stable operation, the welding quality will be able to steadily improve.
2016年9月28日星期三
Application and Management of High Frequency Welding Machine in ERW Weld Pipeline
In the caliber of longitudinal welded pipe production line is set welding, finishing, pipe processing, pipe casing heat treatment in one of the pipe production line. ERW steel pipe line which introduced the German SMS Meer company developed molding equipment and technology, and equipped with the world's most advanced non-destructive testing equipment, high-frequency welding equipment, heat treatment of welding equipment.
The welding of forming steel pipe is the core part of welded pipe line, the quality of welding directly determines the qualified rate of the product. With the power components and power electronics technology continues to develop, as well as heating, melting, welding equipment to promote the demand for induction, induction welding equipment technology has also been an unprecedented opportunity for development. Power components from the tube to the SCR, MOSFET to IGBT gradually adopted, induction device power, frequency is also gradually increased.
ERW pipe unit has absorbed the development experience of similar units in the world, combined with the development of the world's advanced high-frequency induction technology, using EFD IGBT-based high-power high-frequency induction welding technology. The device can be used as induction welder, can also replace the load into contact welding machine. The advantages of contact welding is high efficiency, low power consumption, but its drawback is easy to leave contact block scratches and EDM burn marks. Therefore, in view of the user's quality requirements of the continuous improvement of high-frequency induction welding in the 20th century, 90 years has been a great application.
The welding principle of the contact welding is basically the same as that of the induction welding. The difference is that the induction welding requires the coil to be set on the forming steel pipe, and the contact welding is pressing the two edges of the steel strip through the contact shoe. Induction welding current is a high-frequency current through the coil out of the current induction, and contact welding current is the direct use of high-frequency power supply current. Therefore, the contact welding efficiency is significantly higher than the induction welding, but also easy to produce contact scratches and spark burn marks.
The welding of forming steel pipe is the core part of welded pipe line, the quality of welding directly determines the qualified rate of the product. With the power components and power electronics technology continues to develop, as well as heating, melting, welding equipment to promote the demand for induction, induction welding equipment technology has also been an unprecedented opportunity for development. Power components from the tube to the SCR, MOSFET to IGBT gradually adopted, induction device power, frequency is also gradually increased.
ERW pipe unit has absorbed the development experience of similar units in the world, combined with the development of the world's advanced high-frequency induction technology, using EFD IGBT-based high-power high-frequency induction welding technology. The device can be used as induction welder, can also replace the load into contact welding machine. The advantages of contact welding is high efficiency, low power consumption, but its drawback is easy to leave contact block scratches and EDM burn marks. Therefore, in view of the user's quality requirements of the continuous improvement of high-frequency induction welding in the 20th century, 90 years has been a great application.
The welding principle of the contact welding is basically the same as that of the induction welding. The difference is that the induction welding requires the coil to be set on the forming steel pipe, and the contact welding is pressing the two edges of the steel strip through the contact shoe. Induction welding current is a high-frequency current through the coil out of the current induction, and contact welding current is the direct use of high-frequency power supply current. Therefore, the contact welding efficiency is significantly higher than the induction welding, but also easy to produce contact scratches and spark burn marks.
2016年9月27日星期二
Welding Defects of High Frequency Welded Pipe and Its Analysis
High frequency straight seam welded steel pipe（hfw steel pipe) welding quality defects are cracks, welding, water leakage, scratches and so on.
First, cracks
Fracture is the main defect of welded pipe, its manifestation can be by the usual cracks, local periodic cracks, irregular intermittent cracks. Some of the steel pipe after welding surface without cracks, but by the flattening,
straightening or hydrostatic test cracks. Severe leakage will leak. There are many causes of cracks. Elimination of cracks is one of the most difficult problems in welding adjustment operations.
Second, take the welding
Lap welding is the edge of the tube in the welding when the dislocation, although the curette can still see the traces of dislocation.
1) Molding quality is not good. Forming the edge of the tube is not usually appear on both sides of the usual lap welding, forming the edge of the wave and the drum package, the local small lap.
2) The production of thin-walled tube, the squeeze pressure properly, easily lead to drought. In the squeeze roll hole type center tube inside the installation of a small roller, can effectively overcome the thin-walled pipe lap welding.
3) Extrusion roller installation uneven, a high and one low, resulting in welding.
4) Strip edge slitting bad, curling or edge burr is too large, resulting in lap welding.
5) Forming vertical roller, horizontal roller and squeeze roll rolling center line is not a straight line, or a sickle with steel bends, resulting in unstable molding, weld reverse, resulting in lap welding.
6) When the position of the front end of the resistor is just at the center of the squeeze roll, the flaring strength value and the crushing strength value are the best. When the center line than the extrusion roller, stretching to the sizer side, the flaring strength and crush strength are significantly reduced. When less than the center line in the molding machine side, but also reduce the welding strength
First, cracks
Fracture is the main defect of welded pipe, its manifestation can be by the usual cracks, local periodic cracks, irregular intermittent cracks. Some of the steel pipe after welding surface without cracks, but by the flattening,
straightening or hydrostatic test cracks. Severe leakage will leak. There are many causes of cracks. Elimination of cracks is one of the most difficult problems in welding adjustment operations.
Second, take the welding
Lap welding is the edge of the tube in the welding when the dislocation, although the curette can still see the traces of dislocation.
1) Molding quality is not good. Forming the edge of the tube is not usually appear on both sides of the usual lap welding, forming the edge of the wave and the drum package, the local small lap.
2) The production of thin-walled tube, the squeeze pressure properly, easily lead to drought. In the squeeze roll hole type center tube inside the installation of a small roller, can effectively overcome the thin-walled pipe lap welding.
3) Extrusion roller installation uneven, a high and one low, resulting in welding.
4) Strip edge slitting bad, curling or edge burr is too large, resulting in lap welding.
5) Forming vertical roller, horizontal roller and squeeze roll rolling center line is not a straight line, or a sickle with steel bends, resulting in unstable molding, weld reverse, resulting in lap welding.
6) When the position of the front end of the resistor is just at the center of the squeeze roll, the flaring strength value and the crushing strength value are the best. When the center line than the extrusion roller, stretching to the sizer side, the flaring strength and crush strength are significantly reduced. When less than the center line in the molding machine side, but also reduce the welding strength
ERW Pipe Production Process and Rolling Groove Processing Principle
At present, ordinary fluid on the market with the general Longitudinal Welded Pipe is generally used in high-frequency resistance welding production, which is characterized by high production efficiency, weld heat affected zone is small, low quality requirements on the bonding surface, but the molding quality requirements, forming process Any change in the shape of the V-shaped opening may cause welding quality problems.
Rolling groove processing is the use of grooved joints as pipe fittings when the pipe pretreatment process. Its operating principle is the use of roll groove rolling machine driven rotating pipe, pipe radial direction of the follow-up pressure roller radial pressure applied to the use of the structure of the pressure roller welded pipe in a fixed position of cold out a specified groove.
A "roll groove cracking" is the root cause of the weld strength is not enough, coupled with rolling groove processing of the severe deformation, resulting in weld stress concentration and tear. Raw material is the source of product quality, production must master its characteristics. From the welding point of view, the impact of raw materials on the quality of the weld is mainly reflected in the welding of the material and the two aspects of organization. Elements
of alloying elements and the morphology of the weld quality also affect. The high content of sulfur and phosphorus in the material will easily cause crystallization segregation; the high carbon content will promote the formation of martensite, the embrittlement of the weld metal; the grain size of the metal structure is too large, the direction of the weld crystal will be strengthened; Easy to promote the segregation of impurities. There are non-metallic materials in the inclusion, stratification, width and thickness fluctuations, all kinds of factors may cause weld cracks and reduce weld strength.
ERW steel pipe main welding process parameters are input power, raw production speed, opening angle, welding pressure, induction coil (induction contact) and the location of the impedance and so on. The unreasonable setting of welding
parameters is an important reason for the phenomenon of rolling groove cracking. If the input power is not enough, the speed is too fast, the input heat is insufficient, the edge of the steel strip is not completely melted, the end solid oxide can not be extruded out to form the low-temperature welding defect; conversely, the input heat is too large, , Metal splash and return inclusions and other defects. Secondly, the welding pressure is also important. If the welding
pressure is not enough, the fusion line on both sides of the metal microstructure flow line is not obvious, welding strength will not meet the requirements; the other hand, the welding pressure is too large, irregular weld lines, metal
flow line rise angle is too large, Reduced only when the welding pressure is appropriate should be, the fusion line without distortion, metal streamline angle of 45 °~ 60 °ideal state, the weld strength is guaranteed.
Rolling groove processing is the use of grooved joints as pipe fittings when the pipe pretreatment process. Its operating principle is the use of roll groove rolling machine driven rotating pipe, pipe radial direction of the follow-up pressure roller radial pressure applied to the use of the structure of the pressure roller welded pipe in a fixed position of cold out a specified groove.
A "roll groove cracking" is the root cause of the weld strength is not enough, coupled with rolling groove processing of the severe deformation, resulting in weld stress concentration and tear. Raw material is the source of product quality, production must master its characteristics. From the welding point of view, the impact of raw materials on the quality of the weld is mainly reflected in the welding of the material and the two aspects of organization. Elements
of alloying elements and the morphology of the weld quality also affect. The high content of sulfur and phosphorus in the material will easily cause crystallization segregation; the high carbon content will promote the formation of martensite, the embrittlement of the weld metal; the grain size of the metal structure is too large, the direction of the weld crystal will be strengthened; Easy to promote the segregation of impurities. There are non-metallic materials in the inclusion, stratification, width and thickness fluctuations, all kinds of factors may cause weld cracks and reduce weld strength.
ERW steel pipe main welding process parameters are input power, raw production speed, opening angle, welding pressure, induction coil (induction contact) and the location of the impedance and so on. The unreasonable setting of welding
parameters is an important reason for the phenomenon of rolling groove cracking. If the input power is not enough, the speed is too fast, the input heat is insufficient, the edge of the steel strip is not completely melted, the end solid oxide can not be extruded out to form the low-temperature welding defect; conversely, the input heat is too large, , Metal splash and return inclusions and other defects. Secondly, the welding pressure is also important. If the welding
pressure is not enough, the fusion line on both sides of the metal microstructure flow line is not obvious, welding strength will not meet the requirements; the other hand, the welding pressure is too large, irregular weld lines, metal
flow line rise angle is too large, Reduced only when the welding pressure is appropriate should be, the fusion line without distortion, metal streamline angle of 45 °~ 60 °ideal state, the weld strength is guaranteed.
Cold Pressure Welding
Cold pressure welding, at room temperature conditions, with the help of the metal to be welded to produce plastic deformation and solid-state welding method. Pressure deformation, the workpiece contact surface of the oxide film is destroyed and squeezed out, so that pure metal contacts to achieve intergranular bonding, to clean the welded joints. The applied pressure is generally higher than the yield strength of the material to produce 60 to 90% of the deformation. Pressing method can be slow extrusion, rolling or impact, can also be divided into several times to achieve the required amount of deformation.
The main technical parameters of welding are determined by the mold size, so it is easy to operate and automation, the welding quality is stable, the productivity is high, the cost is low; Do not use flux, the joint will not cause corrosion. ; Welding joint temperature does not rise, the material crystalline state unchanged, especially for dissimilar metals and heat welding can not be achieved in a number of metal materials and products welding. Cold welding has become the electrical industry, aluminum products and space welding the most important in the field of one of several limited welding methods.
Cold presses and the surface of the die may accumulate metal debris, must be regularly removed. If compressed air, compressed air can be used to blow off the debris. If you want to completely remove the debris, you can remove the mold from the welder, the mold of the four modules apart, with a magnifying glass carefully each module to ensure that all the surface of the module trace debris have been cleared. Mold removal must be careful, especially small springs easy to lose. The unclean surface of the mold will cause the wires to slip easily in the mold, so that the welding fails. Note that the mold after the maintenance of the work surface must not allow any grease.
The main technical parameters of welding are determined by the mold size, so it is easy to operate and automation, the welding quality is stable, the productivity is high, the cost is low; Do not use flux, the joint will not cause corrosion. ; Welding joint temperature does not rise, the material crystalline state unchanged, especially for dissimilar metals and heat welding can not be achieved in a number of metal materials and products welding. Cold welding has become the electrical industry, aluminum products and space welding the most important in the field of one of several limited welding methods.
Cold presses and the surface of the die may accumulate metal debris, must be regularly removed. If compressed air, compressed air can be used to blow off the debris. If you want to completely remove the debris, you can remove the mold from the welder, the mold of the four modules apart, with a magnifying glass carefully each module to ensure that all the surface of the module trace debris have been cleared. Mold removal must be careful, especially small springs easy to lose. The unclean surface of the mold will cause the wires to slip easily in the mold, so that the welding fails. Note that the mold after the maintenance of the work surface must not allow any grease.
Cold Welding
Cold welding is the application of mechanical force, molecular force or power to make welding material diffusion to the surface of a process equipment (method). At the microscopic scale, this phenomenon is closely related to the diffusion of atoms on the surface of the material.
Cold welding machine can be divided into welding, cold welding machine, paste-type repair of cold welding, welding copper and aluminum wire cold welding machine. The former two are used to repair metal, casting surface wear, scratches, porosity, trachoma and other small defects; the latter for welding copper wire, aluminum and other non-ferrous metal wire, such as motor welding enameled wire.
Due to the cold welding difference and the traditional sense of welding, cold solder hardness, adhesion and strength is particularly high, almost no shrinkage, can reliably prevent many chemical effects, physical stress and mechanical stress, it is also called "liquid metal". The use of reasonable technology, select the appropriate chemical bonding materials (adhesives, sealants, retaining agent, repair agent, etc.) will be the same material or dissimilar materials connected together to achieve connectivity, sealing, holding, functional coating, One of the main applications currently.
Cold welding can be used for all metals and almost all other raw materials to connect with each other, fixed welding and sealing, hardening and metal can file, planing, grinding, milling, polishing, cars, shot peening, Kinds of tools for processing. For the repair of old equipment, to reduce the manufacturing process of waste defective, is of great significance. Moreover, the connection of some materials with the general welding method, because the welding temperature is high, not only detrimental to the strength of the material, but also easy to deformation, especially for thin material even more problematic. However, these problems do not exist for cold welding, because the cold welding is carried out at room temperature, while the stress of the joints can be more evenly distributed in all the plastic surface, thereby improving the metal due to welding, riveting, bolting caused by Of the above part of the problem, increased fatigue life.
With the application of cold welding technology is mature, polymer composites cold welding applications are more stable and widespread, and nano-materials between the cold welding is gaining more and more attention, including nano-assembly and advanced manufacturing, biosensor, the next Generation microelectronic components and chip interconnect technology.
Cold welding machine can be divided into welding, cold welding machine, paste-type repair of cold welding, welding copper and aluminum wire cold welding machine. The former two are used to repair metal, casting surface wear, scratches, porosity, trachoma and other small defects; the latter for welding copper wire, aluminum and other non-ferrous metal wire, such as motor welding enameled wire.
Due to the cold welding difference and the traditional sense of welding, cold solder hardness, adhesion and strength is particularly high, almost no shrinkage, can reliably prevent many chemical effects, physical stress and mechanical stress, it is also called "liquid metal". The use of reasonable technology, select the appropriate chemical bonding materials (adhesives, sealants, retaining agent, repair agent, etc.) will be the same material or dissimilar materials connected together to achieve connectivity, sealing, holding, functional coating, One of the main applications currently.
Cold welding can be used for all metals and almost all other raw materials to connect with each other, fixed welding and sealing, hardening and metal can file, planing, grinding, milling, polishing, cars, shot peening, Kinds of tools for processing. For the repair of old equipment, to reduce the manufacturing process of waste defective, is of great significance. Moreover, the connection of some materials with the general welding method, because the welding temperature is high, not only detrimental to the strength of the material, but also easy to deformation, especially for thin material even more problematic. However, these problems do not exist for cold welding, because the cold welding is carried out at room temperature, while the stress of the joints can be more evenly distributed in all the plastic surface, thereby improving the metal due to welding, riveting, bolting caused by Of the above part of the problem, increased fatigue life.
With the application of cold welding technology is mature, polymer composites cold welding applications are more stable and widespread, and nano-materials between the cold welding is gaining more and more attention, including nano-assembly and advanced manufacturing, biosensor, the next Generation microelectronic components and chip interconnect technology.
2016年9月26日星期一
Seamless Steel Product By Application
Classfication of seamless steel pipe by application
1. Line pipe.
Such as: water, gas pipes, steam pipes seamless pipe, oil pipeline, oil and gas line pipe. Agricultural irrigation faucet with pipes and sprinkler pipe.
2. Thermal equipment tube.
Such as general boiler boiling water pipe, superheated steam pipes, locomotive boiler superheater tubes, opium pipe, small pipe, brick arch pipe and high-temperature high-pressure boiler tubes.
3. Mechanical industrial pipe.
Such as aviation structural tube (tube, oval tube, flat oval tube), automobile axle tube, axle tubes, structural tubes automobile and tractor, tractor oil cooler tube, farm with a square tube and rectangular tube, transformer tube and bearing tubes.
4. Petroleum geological drilling pipe.
Such as: oil drilling pipe, drill pipe (Kelly and hexagonal drill), drill collar, oil tubing, casing and various fittings, geological drilling pipe (core pipe, casing, active drill pipe, drill collar press hoop and pin connectors, etc.).
5. Chemical industrial pipe.
Such as: petroleum cracking tube, chemical equipment, pipes and tube heat exchangers, acid-resistant stainless pipe, fertilizer use and transport chemical medium pressure pipe with a pipe.
6. Other departments tube.
Such as: container tube (high pressure gas cylinder pipe and tube container ships), instrumentation tube, watch shell tube, needles and tubes and other medical devices.
1. Line pipe.
Such as: water, gas pipes, steam pipes seamless pipe, oil pipeline, oil and gas line pipe. Agricultural irrigation faucet with pipes and sprinkler pipe.
2. Thermal equipment tube.
Such as general boiler boiling water pipe, superheated steam pipes, locomotive boiler superheater tubes, opium pipe, small pipe, brick arch pipe and high-temperature high-pressure boiler tubes.
3. Mechanical industrial pipe.
Such as aviation structural tube (tube, oval tube, flat oval tube), automobile axle tube, axle tubes, structural tubes automobile and tractor, tractor oil cooler tube, farm with a square tube and rectangular tube, transformer tube and bearing tubes.
4. Petroleum geological drilling pipe.
Such as: oil drilling pipe, drill pipe (Kelly and hexagonal drill), drill collar, oil tubing, casing and various fittings, geological drilling pipe (core pipe, casing, active drill pipe, drill collar press hoop and pin connectors, etc.).
5. Chemical industrial pipe.
Such as: petroleum cracking tube, chemical equipment, pipes and tube heat exchangers, acid-resistant stainless pipe, fertilizer use and transport chemical medium pressure pipe with a pipe.
6. Other departments tube.
Such as: container tube (high pressure gas cylinder pipe and tube container ships), instrumentation tube, watch shell tube, needles and tubes and other medical devices.
Seamless Steel Pipe Connection
Seamless steel pipe connection is following below:
Pipe coupling according to the pipe end can be divided into: light pipe (pipe end without threads) and threading pipe (pipe end threaded).
Car wire tube is divided into: general threading pipe and threading pipe end upsetting.
Thick threading pipe can be divided into: EUE (with external thread), internal upset (with internal thread) and internal and external thickening (with external threads), etc. threading pipe.
If you press threading pipe thread type can be divided into: ordinary cylindrical or conical screw thread and other places of special threading pipe. In addition, according to user needs, threading pipe is generally equipped with fittings delivery.
Pipe coupling according to the pipe end can be divided into: light pipe (pipe end without threads) and threading pipe (pipe end threaded).
Car wire tube is divided into: general threading pipe and threading pipe end upsetting.
Thick threading pipe can be divided into: EUE (with external thread), internal upset (with internal thread) and internal and external thickening (with external threads), etc. threading pipe.
If you press threading pipe thread type can be divided into: ordinary cylindrical or conical screw thread and other places of special threading pipe. In addition, according to user needs, threading pipe is generally equipped with fittings delivery.
2016年9月24日星期六
Tips of Improving Straight Seam Steel Pipe Surface Wall Thickness
1, Tube heating
The average heating to stop the rapid rise and fall of temperature. To adhere to a smooth landing every time the temperature slowly, the temperature does not exceed the maximum landing 30 ℃.
2, Mandrel mill
The average wall thickness of the thick-walled tubes and solid billets, so that the probability of a significant reduction in the mandrel bending deformation, can be useful for the progress of the wall thickness precision steel pipe.
3, Precision of the mandrel
Mandrel outer precision control at ± 0.1mm, straight degrees mandrel deflection does not exceed 5mm. Welding, finishing pierce a pin positioned between two sections of the mandrel, in order to avoid the formation of solder total straightness deviation is too large.
4, Perfect process
Perfect process, to avoid the center and pull the thin wall thickness by Haou transcend the limitations of the control condition seizures, progressive wall thickness accuracy.
5, Centering rollers
Determining whether the centering roller assembly in place, adjust the rollers hold the central core, open angle and various initiatives ashamed size consistent in the middle to hold the core roll rolling line.
6, Piercing mandrel
Normal Select piercing mandrel outer diameter Φ108mm-Φ114mm, wall thickness and wall thickness requirements ≥25mm average of thick-walled tube.
7, Intermediate rolling line
Ensure that punch line and the middle of rolling the car in the middle perforation lines consistent and prevent "rolling on" or "rolling down" so that the tube adhere average force at the time of perforation.
8, Things rolling
Head wear on the guide plate and roller rolling things to change in real time.
9, Rolling means something
Roller distance, middle distance necessary to guide the rolling line. Guarantee and roll away from the guide wire in the middle of the middle of the piercing and rolling line, namely the upper and lower roller pitch equal distance about equal to the guide. In the straight seam steel pipe production process, because the primary process is in a hot state, so the heating operation is resolution product quality is very important process. This operation is the key blank is heated uniformly heated to a temperature suitable for processing.
Heating will be wrong in the outer surface of the tube surface may exhibit cracks, folds and migraine pain and other waste reason. Because a great impact on the quality of the perforation, that is, when the temperature of the process piercing is an important condition affecting the quality, it is generally the temperature of the billet piercing working is to manipulate. The second key is to try to reduce the heating operation scale quantities. Especially in hot kneading the elbow, leaving the surface quality of life several things and kneading pipe, pleading even more severe.
The average heating to stop the rapid rise and fall of temperature. To adhere to a smooth landing every time the temperature slowly, the temperature does not exceed the maximum landing 30 ℃.
2, Mandrel mill
The average wall thickness of the thick-walled tubes and solid billets, so that the probability of a significant reduction in the mandrel bending deformation, can be useful for the progress of the wall thickness precision steel pipe.
3, Precision of the mandrel
Mandrel outer precision control at ± 0.1mm, straight degrees mandrel deflection does not exceed 5mm. Welding, finishing pierce a pin positioned between two sections of the mandrel, in order to avoid the formation of solder total straightness deviation is too large.
4, Perfect process
Perfect process, to avoid the center and pull the thin wall thickness by Haou transcend the limitations of the control condition seizures, progressive wall thickness accuracy.
5, Centering rollers
Determining whether the centering roller assembly in place, adjust the rollers hold the central core, open angle and various initiatives ashamed size consistent in the middle to hold the core roll rolling line.
6, Piercing mandrel
Normal Select piercing mandrel outer diameter Φ108mm-Φ114mm, wall thickness and wall thickness requirements ≥25mm average of thick-walled tube.
7, Intermediate rolling line
Ensure that punch line and the middle of rolling the car in the middle perforation lines consistent and prevent "rolling on" or "rolling down" so that the tube adhere average force at the time of perforation.
8, Things rolling
Head wear on the guide plate and roller rolling things to change in real time.
9, Rolling means something
Roller distance, middle distance necessary to guide the rolling line. Guarantee and roll away from the guide wire in the middle of the middle of the piercing and rolling line, namely the upper and lower roller pitch equal distance about equal to the guide. In the straight seam steel pipe production process, because the primary process is in a hot state, so the heating operation is resolution product quality is very important process. This operation is the key blank is heated uniformly heated to a temperature suitable for processing.
Heating will be wrong in the outer surface of the tube surface may exhibit cracks, folds and migraine pain and other waste reason. Because a great impact on the quality of the perforation, that is, when the temperature of the process piercing is an important condition affecting the quality, it is generally the temperature of the billet piercing working is to manipulate. The second key is to try to reduce the heating operation scale quantities. Especially in hot kneading the elbow, leaving the surface quality of life several things and kneading pipe, pleading even more severe.
Notes of Seamless Steel Pipe Production Process Equipment Points
1. Oiled marking: steel pipe hydrostatic testing machine after passing were oiled to prevent corrosion, and according to user requirements for marking.
2. Leveling milling: the flat steel anvil machine so that the original curl, and then through the edge milling machine for two-sided steel milling, so as to meet the requirements of the plate width, plate edge parallelism and groove shape.
3. Shear molding: the steel plate production line along the outer edge of the spiral curl into a tube.
4. Butt cut: seamless steel pipe market equipment using advanced technology pre double submerged arc welding, internal welding, outside welding. The welded steel pipe using a plasma-foot cut to specification length.
5. Visual inspection: by professional and technical personnel to some of the basic parameters to be checked.
6. The ultrasonic flaw detection: scrap development of the inner and outer sides of the base metal and weld seam 100% inspection.
7. X-ray detection: internal and external welds 100% X-ray industrial TV check image processing system to ensure that the use of detection sensitivity.
8. The pressure test: the steel pipe hydrostatic testing machine shall be tested individually to ensure that the test pressure pipe meet the required standards.
9. Chamfering flat head: seamless steel pipe inspection devices will be qualified after the pipe end processing, to meet the requirements of the pipe end (spiral welded pipe mill) groove dimensions.
10. Final inspection: leveler again ultrasound and X-ray detection as well as magnetic particle inspection pipe end, check if there are problems and welding pipe ends defects.
11. Unwinding board probe: After entering the unwinding plate production line, the first full-board ultrasonic testing.
2. Leveling milling: the flat steel anvil machine so that the original curl, and then through the edge milling machine for two-sided steel milling, so as to meet the requirements of the plate width, plate edge parallelism and groove shape.
3. Shear molding: the steel plate production line along the outer edge of the spiral curl into a tube.
4. Butt cut: seamless steel pipe market equipment using advanced technology pre double submerged arc welding, internal welding, outside welding. The welded steel pipe using a plasma-foot cut to specification length.
5. Visual inspection: by professional and technical personnel to some of the basic parameters to be checked.
6. The ultrasonic flaw detection: scrap development of the inner and outer sides of the base metal and weld seam 100% inspection.
7. X-ray detection: internal and external welds 100% X-ray industrial TV check image processing system to ensure that the use of detection sensitivity.
8. The pressure test: the steel pipe hydrostatic testing machine shall be tested individually to ensure that the test pressure pipe meet the required standards.
9. Chamfering flat head: seamless steel pipe inspection devices will be qualified after the pipe end processing, to meet the requirements of the pipe end (spiral welded pipe mill) groove dimensions.
10. Final inspection: leveler again ultrasound and X-ray detection as well as magnetic particle inspection pipe end, check if there are problems and welding pipe ends defects.
11. Unwinding board probe: After entering the unwinding plate production line, the first full-board ultrasonic testing.
2016年9月23日星期五
Non-destructive Testing of Straight Seam Steel Surface
Surface NDT methods of straight seam steel selection principles: magnetic iron pipe should be used in magnetic particle testing; non-ferromagnetic steel should be used in penetration testing. Delayed cracking tendency of welded joints, the surface should be non-destructive testing after welding cooling certain time; reheat cracking tendency of welded joints, the surface should be in non-destructive testing and post-weld heat treatment once each.
Surface non-destructive testing applications in accordance with the standard requirements that detects objects and applications in general as follows:
(1) An outer surface of the tube material quality inspection.
(2) Important butt weld surface defect detection.
(3) Important fillet surface defect detection.
(4) Important socket weld and jumper tee branch pipe defect detection.
(5) Pipe bending surface defect detection.
(6) The material tends to quench detection larger groove welded joints.
(7) The design temperature is below zero or non-austenitic stainless steel pipe beveling detected 29 degrees Celsius.
(8) The provisions of the double-sided weldment after weld gouging gouging detection
(9) When using oxyacetylene flame cutting jig welded pipes alloy hardening tendency on when grinding parts defect detection.
Surface non-destructive testing applications in accordance with the standard requirements that detects objects and applications in general as follows:
(1) An outer surface of the tube material quality inspection.
(2) Important butt weld surface defect detection.
(3) Important fillet surface defect detection.
(4) Important socket weld and jumper tee branch pipe defect detection.
(5) Pipe bending surface defect detection.
(6) The material tends to quench detection larger groove welded joints.
(7) The design temperature is below zero or non-austenitic stainless steel pipe beveling detected 29 degrees Celsius.
(8) The provisions of the double-sided weldment after weld gouging gouging detection
(9) When using oxyacetylene flame cutting jig welded pipes alloy hardening tendency on when grinding parts defect detection.
Shape Requirements of LSAW Steel Pipe
LSAW steel pipe weld appearance basic requirements:
Straight seam steel pipe before NDT, weld visual inspection should meet the requirements. General requirements for straight seam steel pipe weld appearance and surface quality of welded joints are as follows:
Welding should look good shape, width of each side groove edge 2mm overshadowed appropriate. Fillet weld leg height should meet the design requirements, the shape should be smooth transition.
Welded joint surface requirements:
(1) Does not allow cracks, lack of fusion, pores, slag, spatter exist.
(2) The design temperature is below -29 degrees pipes, stainless steel and hardened alloy steel pipes tend to be larger weld surface, without undercut. Other material pipe weld undercut depth should be greater than 0.5mm, continuous undercut length should not exceed 100mm, and both sides of the weld undercut always grow up to 10 percent of the entire length of the weld.
(3) Shall not be lower than the surface of the weld surface of the pipe. Weld reinforcement and no more than 3mm, (the maximum width of weld joints after groove).
(4) Welded joints the wrong side of the wall thickness should be less than 10% and not more than 2mm.
Straight seam steel pipe before NDT, weld visual inspection should meet the requirements. General requirements for straight seam steel pipe weld appearance and surface quality of welded joints are as follows:
Welding should look good shape, width of each side groove edge 2mm overshadowed appropriate. Fillet weld leg height should meet the design requirements, the shape should be smooth transition.
Welded joint surface requirements:
(1) Does not allow cracks, lack of fusion, pores, slag, spatter exist.
(2) The design temperature is below -29 degrees pipes, stainless steel and hardened alloy steel pipes tend to be larger weld surface, without undercut. Other material pipe weld undercut depth should be greater than 0.5mm, continuous undercut length should not exceed 100mm, and both sides of the weld undercut always grow up to 10 percent of the entire length of the weld.
(3) Shall not be lower than the surface of the weld surface of the pipe. Weld reinforcement and no more than 3mm, (the maximum width of weld joints after groove).
(4) Welded joints the wrong side of the wall thickness should be less than 10% and not more than 2mm.
2016年9月20日星期二
Line Pipe Plate Production
Line pipe used plates 60 to 70 years using the Anshan Iron and Steel and other major manufacturers A3,16Mn, with diameter pipeline delivery pressure increases and progress strength steel can not meet demand. 80 years after each oil pipe plant started by the United States API standard production pipeline steel, because of the domestic pipeline board manufacturing plant immature technology, mainly imported plate. Enter the 1990s, the domestic plate production line developed rapidly, Baosteel, Wuhan Iron and Steel, Anshan, Benxi Iron and Steel, Panzhihua Iron and Steel and other enterprises have developed and produced a series of high-grade steel X pipeline.
In the domestic pipeline steel production process are: a conventional semi-continuous hot rolling, CSP continuous casting and rolling, plate units, Steckel unit.
1) Semi-continuous rolling mill: Includes 1 rack 5 rack Steckel mill and finishing mill. In the semi-continuous rolling mills, strip the finish rolling experienced hot-rolled steel strip from one end to the other end is substantially constant. On finishing mill time between passes is generally less than 3s.
2) CSP continuous casting and rolling: in CSP production line containing niobium, vanadium, titanium composite micro-alloyed carbon steel, the use of appropriate controlled rolling and cooling and coiling process can ensure the mechanical properties and microstructure of steel modern organizations meet the technical requirements of X60 pipeline steel, pipeline steel in line with modern trends. Our CSP continuous casting and rolling production line has been developed to X60 steel, while the United States and other foreign manufacturers CSP has developed and produced high-grade pipeline steel X60, X65 and the X70. Which process is characterized by the presence of thin slab centerline segregation, eliminate thin slab centerline segregation is to further improve the quality of key pipeline technical problems.
3) Plate Unit: The main production of heavy plate for LSAW pipe production, reliable straight seam submerged arc welded pipe, widely used in high-voltage transmission and gas trunk line.
4) Steckel: Steckel mill comprises a reciprocating roughing mill and a finishing mill 4 roll back and forth. In the finishing mill both sides of the conveyor line installed two hot roll mill. Output roller typically comprises a laminar cooling system and a take-up station. On the Steckel mill, thermo-mechanical history of the entire length of the strip on the significant changes, especially in the micro-alloyed steel production, will strongly influence the degree of recrystallization generated in the finishing mill, grain growth and precipitation, and cause the entire dramatic changes in the final microstructure and mechanical properties of the strip length. Which process is characterized by relatively low investment costs.
In the domestic pipeline steel production process are: a conventional semi-continuous hot rolling, CSP continuous casting and rolling, plate units, Steckel unit.
1) Semi-continuous rolling mill: Includes 1 rack 5 rack Steckel mill and finishing mill. In the semi-continuous rolling mills, strip the finish rolling experienced hot-rolled steel strip from one end to the other end is substantially constant. On finishing mill time between passes is generally less than 3s.
2) CSP continuous casting and rolling: in CSP production line containing niobium, vanadium, titanium composite micro-alloyed carbon steel, the use of appropriate controlled rolling and cooling and coiling process can ensure the mechanical properties and microstructure of steel modern organizations meet the technical requirements of X60 pipeline steel, pipeline steel in line with modern trends. Our CSP continuous casting and rolling production line has been developed to X60 steel, while the United States and other foreign manufacturers CSP has developed and produced high-grade pipeline steel X60, X65 and the X70. Which process is characterized by the presence of thin slab centerline segregation, eliminate thin slab centerline segregation is to further improve the quality of key pipeline technical problems.
3) Plate Unit: The main production of heavy plate for LSAW pipe production, reliable straight seam submerged arc welded pipe, widely used in high-voltage transmission and gas trunk line.
4) Steckel: Steckel mill comprises a reciprocating roughing mill and a finishing mill 4 roll back and forth. In the finishing mill both sides of the conveyor line installed two hot roll mill. Output roller typically comprises a laminar cooling system and a take-up station. On the Steckel mill, thermo-mechanical history of the entire length of the strip on the significant changes, especially in the micro-alloyed steel production, will strongly influence the degree of recrystallization generated in the finishing mill, grain growth and precipitation, and cause the entire dramatic changes in the final microstructure and mechanical properties of the strip length. Which process is characterized by relatively low investment costs.
Characteristics of Pipe Cold Rolling
After a series of cold-rolled pipe has the following characteristics:
1, Through the organization of cold rolled grain fine pipe, pipe mechanical and physical properties compared with the superior;
2, Cold rolling mill for the correction capability of the original tube wall thickness deviation is large, precise geometry, low surface roughness;
3, Pass deformation larger, up to 70% -85%;
4, Cold-rolled production pipe can significantly reduce intermediate steps, such as heat treatment, pickling, beginning, straightening and cutting, to reduce the metal materials, fuel, electricity and other auxiliary materials and human consumption;
5, The method to produce cold-rolled thin wall and ultra-thin wall, inner and outer surfaces scratch-free quality pipe;
6, Be effectively rolled high-alloy, poor ductility various metal pipe.
1, Through the organization of cold rolled grain fine pipe, pipe mechanical and physical properties compared with the superior;
2, Cold rolling mill for the correction capability of the original tube wall thickness deviation is large, precise geometry, low surface roughness;
3, Pass deformation larger, up to 70% -85%;
4, Cold-rolled production pipe can significantly reduce intermediate steps, such as heat treatment, pickling, beginning, straightening and cutting, to reduce the metal materials, fuel, electricity and other auxiliary materials and human consumption;
5, The method to produce cold-rolled thin wall and ultra-thin wall, inner and outer surfaces scratch-free quality pipe;
6, Be effectively rolled high-alloy, poor ductility various metal pipe.
2016年9月19日星期一
Seamless Pipe Rolling
The raw material is rolled seamless steel pipe, tube embryos to go through a cutting machine cutting a length of about 1 meter blank, and by conveyor belt to the furnace heating. The billet is fed into the furnace is heated to a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is the key issue. After a round tube came out to go through the pressure punching machine wear air. Generally more common punch is tapered roller punching machine, punching machine such high production efficiency, product quality, perforated expanding capacity, can be worn a variety of steels. After perforation, round tube has been three-roll rolling, rolling or extrusion. To post extrusion detached sizing. Sizing high-speed rotary cone drill bit through the perforated steel embryo formed steel. Pipe inner diameter is determined by the outer diameter sizing mill drill length.
Pipe by sizing after entering the cooling tower through spray cooling pipe after cooling, will be straightening. After straightening the steel conveyor belt to the metal detection machine (or pressure test) for internal testing. If the thick-walled seamless internal cracks, bubbles and other issues, will be detected. After the selection of steel but also through strict quality control manual. After the steel quality inspection, using spray paint on number, size, production batch number. By a crane into the warehouse.
Pipe by sizing after entering the cooling tower through spray cooling pipe after cooling, will be straightening. After straightening the steel conveyor belt to the metal detection machine (or pressure test) for internal testing. If the thick-walled seamless internal cracks, bubbles and other issues, will be detected. After the selection of steel but also through strict quality control manual. After the steel quality inspection, using spray paint on number, size, production batch number. By a crane into the warehouse.
Cooling Ways of Seamless Steel Billet
According to the chemical composition of the seamless steel pipe, a state organization, product section size, deficiencies that may arise after cooling, and the rolling mill, cooling equipment, space and cooling conditions after hot rolling of steel can be used with different cooling methods to cool to room temperature.
1) Air-cooled
This is the natural air cooling method, it is applied very widely. After all the air is cooled, it is not a martensitic microstructure or steel, the use of air cooling after hot rolling, such as low carbon steel, low-alloy ordinary strength steel, most of the carbon steel and alloy semi-martensitic structure steel, and austenitic stainless steel, and are using this method of cooling.
2) Rapid cooling
It is blowing, spraying, water is forced through the cooling method of steel making process is characterized by a certain period drama cooled to a temperature in the cooled natural. Such as requiring testing carbide steel mesh defects using this cooling method. Carbon steel wire rod also rapid cooling after rolling, in order to improve the overall mechanical properties of the wire.
3) Slow cooling
It features after hot rolling steel slab or stack together to make it slowly cooled, to prevent white spot defects. The specific method of slow cooling according to the production conditions, and can be dedicated slow cooling pit, can be moved in a special slow cooling box to be stacked on the floor, cover with sand, slag and other asbestos insulation was subjected slow cooling. This cold
But approach applies to martensite, martensite and half Ledeburite type of steel, such as high speed tool steel, stainless steel, tool steel and high-alloy section high alloy structure, they produce stress upon cooling very sensitive strong.
4) Heat treatment
After the heat treatment method commonly used hot-rolled annealing, tempering, normalizing.
1) Air-cooled
This is the natural air cooling method, it is applied very widely. After all the air is cooled, it is not a martensitic microstructure or steel, the use of air cooling after hot rolling, such as low carbon steel, low-alloy ordinary strength steel, most of the carbon steel and alloy semi-martensitic structure steel, and austenitic stainless steel, and are using this method of cooling.
2) Rapid cooling
It is blowing, spraying, water is forced through the cooling method of steel making process is characterized by a certain period drama cooled to a temperature in the cooled natural. Such as requiring testing carbide steel mesh defects using this cooling method. Carbon steel wire rod also rapid cooling after rolling, in order to improve the overall mechanical properties of the wire.
3) Slow cooling
It features after hot rolling steel slab or stack together to make it slowly cooled, to prevent white spot defects. The specific method of slow cooling according to the production conditions, and can be dedicated slow cooling pit, can be moved in a special slow cooling box to be stacked on the floor, cover with sand, slag and other asbestos insulation was subjected slow cooling. This cold
But approach applies to martensite, martensite and half Ledeburite type of steel, such as high speed tool steel, stainless steel, tool steel and high-alloy section high alloy structure, they produce stress upon cooling very sensitive strong.
4) Heat treatment
After the heat treatment method commonly used hot-rolled annealing, tempering, normalizing.
2016年9月18日星期日
Welding Process of Straight Seam Welded Pipe
Longitudinal straight seam welded pipe butt weld joint cross-sectional shape, depending on the thickness of the body to be welded before welding groove and then type two sides. When welding thick steel plate, for penetration in contact at the edges out of various shapes of the groove, so that more easily into the welding rod or wire. Groove patterns are one-sided welding the welding groove and the sides of the groove. When you select groove type, in addition to outside should be considered to ensure penetration welding convenient, less filler metal Chi, small welding deformation and beveling of Longitudinal low cost factor.
Linker connecting the two is in the welding Longitudinal seam formed called weld. Both sides of the weld in the welding welding heat effect will be, but the organization and performance vary, this area is known as the heat affected zone. Welding due to the workpiece material welding materials, Longitudinal welding current so different, after welding may occur in the weld and heat affected zone of overheating, embrittlement, hardening or softening, but also the weldment performance degradation, deterioration of weldability. This need to adjust the welding conditions, before welding weldment interface preheating, post-weld heat when and weld heat treatment can improve the quality of welding weldment quality.
Longitudinal is of two or more homogeneous or heterogeneous material through a combination of diffusion and the question of the atom or molecule is integrally connected to the process, prompting the question of atoms and molecules produce binding and diffusion method is to heat or pressure, or simultaneously heated and pressurized.
In addition, a local weld foot rapid heating and cooling process, the weld zone due to the binding body and four weeks of the workpiece can not freely expand and contract in the weldment after cooling will produce welding stress and deformation. Important product after welding is required to eliminate welding stress, welding distortion correction
Linker connecting the two is in the welding Longitudinal seam formed called weld. Both sides of the weld in the welding welding heat effect will be, but the organization and performance vary, this area is known as the heat affected zone. Welding due to the workpiece material welding materials, Longitudinal welding current so different, after welding may occur in the weld and heat affected zone of overheating, embrittlement, hardening or softening, but also the weldment performance degradation, deterioration of weldability. This need to adjust the welding conditions, before welding weldment interface preheating, post-weld heat when and weld heat treatment can improve the quality of welding weldment quality.
Longitudinal is of two or more homogeneous or heterogeneous material through a combination of diffusion and the question of the atom or molecule is integrally connected to the process, prompting the question of atoms and molecules produce binding and diffusion method is to heat or pressure, or simultaneously heated and pressurized.
In addition, a local weld foot rapid heating and cooling process, the weld zone due to the binding body and four weeks of the workpiece can not freely expand and contract in the weldment after cooling will produce welding stress and deformation. Important product after welding is required to eliminate welding stress, welding distortion correction
How To Deal With The Welding Slag of Spiral Welded Pipe
Spiral welded pipe in recent years, the development of better and better in our lives are often used spiral welded pipe, spiral welded pipe in the welding process but will be some welding slag, which slag require extra care in handling only the spiral welded pipe more smoothly in the next use.
When the spiral welded pipe welding slag welding If welding is best to use, such as stainless steel pipe or cold after hammering, will fall off, these two methods are relatively simple, but not necessarily clean clean. Welding slag is better to clean up bad slag splashing is clear, when welding slag can clean up the electricity, then grind on electricity grinding, welding slag, otherwise it is difficult to be cleaned out. As for the defect occurs when spiral welded pipe cutting is also possible to get rid of us, however, to remove these defects must find a reasonable way only correct way to make pipe defects be remedied. For all these defects can find the appropriate solution, but if you find the right method will allow the use of more trouble. For when cleaning pipe welding slag there is a way you can with a file, with a file can also be cleaned very clean welding slag. There is a simpler way is to take the effort or a saw blade with a half can, out into the pipe, tube left hand, right hand saw blade, clockwise or counterclockwise to the arms pull. This allows spiral welded pipe in the welding slag clean very clean, but also will not waste too much time, simple and convenient.
When the spiral welded pipe welding slag welding If welding is best to use, such as stainless steel pipe or cold after hammering, will fall off, these two methods are relatively simple, but not necessarily clean clean. Welding slag is better to clean up bad slag splashing is clear, when welding slag can clean up the electricity, then grind on electricity grinding, welding slag, otherwise it is difficult to be cleaned out. As for the defect occurs when spiral welded pipe cutting is also possible to get rid of us, however, to remove these defects must find a reasonable way only correct way to make pipe defects be remedied. For all these defects can find the appropriate solution, but if you find the right method will allow the use of more trouble. For when cleaning pipe welding slag there is a way you can with a file, with a file can also be cleaned very clean welding slag. There is a simpler way is to take the effort or a saw blade with a half can, out into the pipe, tube left hand, right hand saw blade, clockwise or counterclockwise to the arms pull. This allows spiral welded pipe in the welding slag clean very clean, but also will not waste too much time, simple and convenient.
2016年9月10日星期六
Automatic Submerged Arc Welding Advantages of Straight Seam Steel Pipe
Submerged arc welding of straight seam steel pipe has the following advantages:
Submerged arc welding heat concentrated, welding safety metal spatter loss, there is no waste of the electrode head, workpiece thickness h may also be without groove, thus saving metal material.
Submerged arc welding can be employed large welding current, arc heat concentration, deep penetration, the wire can be continuously fed unlike electrodes as frequently replaced, so the productivity of 5 to 10 times higher than that of manual arc welding village.
Submerged arc welding is not visible arc welding, welding fumes and rarely, but also mechanical automatic operation, and thus the working conditions have been greatly improved. Submerged arc welding is a limitation: since the arc is not visible, thus demanding joint processing and assembly, welding position subject to certain restrictions, are generally always in flat-position welding.
Submerged arc welding heat concentrated, welding safety metal spatter loss, there is no waste of the electrode head, workpiece thickness h may also be without groove, thus saving metal material.
Submerged arc welding can be employed large welding current, arc heat concentration, deep penetration, the wire can be continuously fed unlike electrodes as frequently replaced, so the productivity of 5 to 10 times higher than that of manual arc welding village.
Submerged arc welding is not visible arc welding, welding fumes and rarely, but also mechanical automatic operation, and thus the working conditions have been greatly improved. Submerged arc welding is a limitation: since the arc is not visible, thus demanding joint processing and assembly, welding position subject to certain restrictions, are generally always in flat-position welding.
ERW,SSAW and LSAW
Straight seam high frequency (ERW) by welding and induction welding is divided into different forms of contact of two welding, hot-rolled wide coil as raw material, through pre-bending, continuous forming, welding, heat treatment, sizing, straightening, cutting, etc. step short compared to the spiral weld, high dimensional accuracy, uniform thickness, surface quality, under pressure advantages, but the disadvantage is that only the production of small diameter thin-walled tube, easy to produce gray leaf spot weld, incomplete fusion ditch-like corrosion defects. Currently wider field of application of city gas, crude oil and other oil products transportation.
Spiral submerged arc (SSAW) pipe volume is the forward direction of its centerline forming tube forming angle (adjustable) while forming side welding, weld into a helix, the advantage of the same specifications can produce a variety of diameters steel, adapt to a wider range of raw materials, the main seam can avoid stress, stress better, disadvantage is poor geometry, straight seam weld length compared to the length of the tube, easy to crack, porosity, slag, weld misalignment such as welding defects, welding stress tension state. General Oil and Gas Pipeline design specification spiral submerged arc used only on class 3 and class 4 area. This process will improve foreign raw materials to the steel sheet, so that forming and welding separately, lean pre-welding and after welding cold expanding, its quality close UOE welded pipe, currently there is no such process, is the improvement of plant direction. "East" is still used in the traditional production process, but the pipe end has been expanding. Deny the United States, Japan and Germany in general SSAW, considered the main line should not be used SSAW; Canada and Italy partially used SSAW, Russia sparingly SSAW, and have developed a very strict additional condition, due to historical reasons, the domestic backbone majority still use SSAW .
Straight seam submerged arc (LSAW) is a single plate as the raw material, the pressure plate (volume) in a mold or a molding machine, using double-sided submerged arc welding and expanding the way from production. Its wide range of product specifications, weld toughness, ductility, uniformity and dense better, having a large diameter, wall thickness, high pressure, low temperature resistance, corrosion resistance and other advantages. When the construction of high strength, high toughness, high-quality long-distance oil and gas pipelines, the required large diameter thick wall pipe is mostly a straight seam submerged arc. According to API standards, in large oil and gas pipelines, when through the alpine zone, sea, densely populated urban areas such as Class 1, Class 2 area, straight seam submerged arc tube is the only designated applicable.
For more, visit the page:http://www.hu-steel.com/news355_342.html
Spiral submerged arc (SSAW) pipe volume is the forward direction of its centerline forming tube forming angle (adjustable) while forming side welding, weld into a helix, the advantage of the same specifications can produce a variety of diameters steel, adapt to a wider range of raw materials, the main seam can avoid stress, stress better, disadvantage is poor geometry, straight seam weld length compared to the length of the tube, easy to crack, porosity, slag, weld misalignment such as welding defects, welding stress tension state. General Oil and Gas Pipeline design specification spiral submerged arc used only on class 3 and class 4 area. This process will improve foreign raw materials to the steel sheet, so that forming and welding separately, lean pre-welding and after welding cold expanding, its quality close UOE welded pipe, currently there is no such process, is the improvement of plant direction. "East" is still used in the traditional production process, but the pipe end has been expanding. Deny the United States, Japan and Germany in general SSAW, considered the main line should not be used SSAW; Canada and Italy partially used SSAW, Russia sparingly SSAW, and have developed a very strict additional condition, due to historical reasons, the domestic backbone majority still use SSAW .
Straight seam submerged arc (LSAW) is a single plate as the raw material, the pressure plate (volume) in a mold or a molding machine, using double-sided submerged arc welding and expanding the way from production. Its wide range of product specifications, weld toughness, ductility, uniformity and dense better, having a large diameter, wall thickness, high pressure, low temperature resistance, corrosion resistance and other advantages. When the construction of high strength, high toughness, high-quality long-distance oil and gas pipelines, the required large diameter thick wall pipe is mostly a straight seam submerged arc. According to API standards, in large oil and gas pipelines, when through the alpine zone, sea, densely populated urban areas such as Class 1, Class 2 area, straight seam submerged arc tube is the only designated applicable.
For more, visit the page:http://www.hu-steel.com/news355_342.html
2016年9月8日星期四
Hydrostatic Pressure Test Methods and Procedures of LSAW Steel Pipe
Large diameter lsaw steel pipe hydrostatic testing machine during the pressure test, the first sealing means by the end of the test straight seam steel pipe sealed at both ends and low-pressure water injection in the exhaust pipe filling process air through the exhaust valve, in after the water is full of low-pressure, high-pressure water injection device through the booster is to pressurize the inner tube until the required test pressure. After reaching a predetermined test pressure predetermined dwell time, if the straight seam steel pipe leak, deformation phenomena in the pressure test is carried out relief. Then open the end seals, low-pressure water discharge, straight seam steel pipe to be tested to check for visual inspection station for suspicious penetration. According to the standard pressure for pressure testing process curve automatic recording device for recording.
Pressure steps:
1. The hydrostatic pressure test pressure Longitudinal working pressure and test pressure of not less than 0.80MPa; Longitudinal such as work pressure is less than 0.8MPa, the hydrostatic test pressure selection 0.8MPa. Pressure test pressure test may not be replaced;
2. Longitudinal not respond after filling water filling exposed connection points (including the Longitudinal and Longitudinal attachment joints), it was discovered leakage should be excluded;
3. Longitudinal pressure test length of not more than 1000m. A fitting intermediate pipe section, hydrostatic testing segment length of not more than 500m, the system has different material Longitudinal pressure test should be carried out separately.
4. When the pressure test pipe ends should be solid and reliable inspection, pressure test, non-support facilities loose chipping off, the valve may not be used as the sealing plate.
5. The pressure should be used mechanical devices with metering device, and accuracy not less than 1.5 (the maximum permissible error does not exceed 1.5% of full scale), scale range should be 1.3 to 1.5 times the test pressure, dial diameter not less than 150mm.
Pressure steps:
1. The hydrostatic pressure test pressure Longitudinal working pressure and test pressure of not less than 0.80MPa; Longitudinal such as work pressure is less than 0.8MPa, the hydrostatic test pressure selection 0.8MPa. Pressure test pressure test may not be replaced;
2. Longitudinal not respond after filling water filling exposed connection points (including the Longitudinal and Longitudinal attachment joints), it was discovered leakage should be excluded;
3. Longitudinal pressure test length of not more than 1000m. A fitting intermediate pipe section, hydrostatic testing segment length of not more than 500m, the system has different material Longitudinal pressure test should be carried out separately.
4. When the pressure test pipe ends should be solid and reliable inspection, pressure test, non-support facilities loose chipping off, the valve may not be used as the sealing plate.
5. The pressure should be used mechanical devices with metering device, and accuracy not less than 1.5 (the maximum permissible error does not exceed 1.5% of full scale), scale range should be 1.3 to 1.5 times the test pressure, dial diameter not less than 150mm.
Weld Flaw Detection Methods of LSAW Steel Pipe
In order to detect LSAW longitudinal weld defects in the weld total length of horizontal or vertical use jet (water column) coupled ultrasonic flaw detection. Jet (water column) ultrasonic flaw detection is between the probe and the pipe coupling by jet, so that the longitudinal wave probe beam emitted by the incident to the interface of water or steel pipe, a steel pipe weld inspection by pure shear wave conversion.Therefore, to achieve the weld pure shear testing, the incident angle of the probe must be between Ⅰ critical angle and the critical angle II, drawn by the law of refraction. Can be obtained by calculating the longitudinal wave is incident from the water to the steel in the first critical angle I and II were critical angle 14.5 ° and 27.3 °.
Longitudinal ultrasonic testing: non-destructive testing is on-site detection, rapid non-destructive, without having to reach the lab, greatly improving efficiency. Analysis speed is much faster than desktop spectrometer, only a few seconds to display the results of the analysis. Small size, light weight, easy to carry.
NDT ultrasonic flaw detection for very many, testing principle Longitudinal not divided: ultrasonic testing, X-ray testing, testing film. Testing methods are: single-sided double-sided testing, double-sided double-sided testing, single-sided unilateral testing.
The choice of which depends on the testing straight seam steel pipe wall thickness and width of the weld, the weld testing if too wide on one side of the double-sided double-sided or double-sided testing (generally used for thick seam width) of Implementation of the standards: GB 11345-89 (most common), GB / T11345-2013. DW1.1 standard inside a two minute testing, usually less demanding steel structure is three testing no matter what standard testing must meet the requirements of customers in accordance with the national standard steel pipe testing to a weld two.
Longitudinal ultrasonic testing: non-destructive testing is on-site detection, rapid non-destructive, without having to reach the lab, greatly improving efficiency. Analysis speed is much faster than desktop spectrometer, only a few seconds to display the results of the analysis. Small size, light weight, easy to carry.
NDT ultrasonic flaw detection for very many, testing principle Longitudinal not divided: ultrasonic testing, X-ray testing, testing film. Testing methods are: single-sided double-sided testing, double-sided double-sided testing, single-sided unilateral testing.
The choice of which depends on the testing straight seam steel pipe wall thickness and width of the weld, the weld testing if too wide on one side of the double-sided double-sided or double-sided testing (generally used for thick seam width) of Implementation of the standards: GB 11345-89 (most common), GB / T11345-2013. DW1.1 standard inside a two minute testing, usually less demanding steel structure is three testing no matter what standard testing must meet the requirements of customers in accordance with the national standard steel pipe testing to a weld two.
2016年9月6日星期二
The Main Features of Welded Pipe
1) Having a longitudinal weld steel pipe, inside and outside welds using a submerged arc welded.
2) After expanding the overall mechanical handling, pipe internal stress is small and evenly distributed, which can effectively prevent stress corrosion cracking, high dimensional accuracy, easy on-site welding construction.
3) After the pre-finish welding the welding process, welding process is stable and high weld quality.
4) Weld production process is easy to implement and use of non-destructive testing in the field of non-destructive testing review.
5) Great specifications, can produce small-diameter, thick wall also produces large-diameter, thick-wall steel pipe.
2) After expanding the overall mechanical handling, pipe internal stress is small and evenly distributed, which can effectively prevent stress corrosion cracking, high dimensional accuracy, easy on-site welding construction.
3) After the pre-finish welding the welding process, welding process is stable and high weld quality.
4) Weld production process is easy to implement and use of non-destructive testing in the field of non-destructive testing review.
5) Great specifications, can produce small-diameter, thick wall also produces large-diameter, thick-wall steel pipe.
Difference between SSAW Steel Pipe and LSAW Steel Pipe on Rupture
For the ssaw steel pipe, although the result of the tensile test specimens substantially independent of sampling direction, but the test results v Charpy impact specimen was closely related to the sampling direction. When sampling along the rolling direction CVN maximum value when the vertical direction of rolling sample CVN value of the minimum.
The difference between the ssaw and lsaw steel pipe on rupture is that the latter is consistent initiation or expansion maximum driving direction of least resistance (are axially), thus initiation and expansion must be carried along to uranium. But on the contrary, spiral initiation or expansion of the maximum driving direction (to oil) and the path of least resistance (the rolling direction) are inconsistent, so the crack initiation and propagation direction there are two possibilities; one axial vent; two along the rolling direction (ie, spiral weld direction).
The ratio is generally considered the maximum and minimum CVN When three or more can be considered to change the split will be determined from the rolling direction.
In some cases, although spiral fracture initiation is in the rolling direction, and a large crack is extended in the axial direction of the case, in the calculation of crack initiation criterion should still pull the rolling direction into account.
The difference between the ssaw and lsaw steel pipe on rupture is that the latter is consistent initiation or expansion maximum driving direction of least resistance (are axially), thus initiation and expansion must be carried along to uranium. But on the contrary, spiral initiation or expansion of the maximum driving direction (to oil) and the path of least resistance (the rolling direction) are inconsistent, so the crack initiation and propagation direction there are two possibilities; one axial vent; two along the rolling direction (ie, spiral weld direction).
The ratio is generally considered the maximum and minimum CVN When three or more can be considered to change the split will be determined from the rolling direction.
In some cases, although spiral fracture initiation is in the rolling direction, and a large crack is extended in the axial direction of the case, in the calculation of crack initiation criterion should still pull the rolling direction into account.
Straight Seam Steel Pipe Corrosion Insulation Processing
Hot straight seam steel pipe manufacturers, the small caliber in the output of crude oil or heating pipes, in order to reduce the heat pipes to the soil, outside the pipe plus insulation composite layer. Commonly used insulation material is a rigid polyurethane foam, a temperature of -185 ~ 120 ℃. This material is soft texture, to increase its strength, insulation on the outside add a layer of high density polyethylene cladding layer, to form a composite structure, in order to prevent infiltration of groundwater within the insulation.
Ordinary straight seam steel pipe for use in harsh environmental conditions, there will be severe corrosion, which will reduce the life of the steel pipe, anti-corrosion pipe insulation is relatively long service life, under normal circumstances can be used are 30-50 years or so, and the correct installation and use is also possible to make the pipe network maintenance costs low, corrosion pipe insulation can also set the alarm system, automatic leak detection pipe network failure, the exact knowledge of the fault location and automatically alarms.
Pipe insulation is widely used in the construction and promotion, and production technology constantly improve and popularize. Pipe insulation has a good performance can promote their use in a good range, different parts of the structure and cooperate with each other in use, play an important role and value. Polyurethane foam has good mechanical properties and thermal insulation properties, usually can be temperature 120 ℃, by modification or other insulating material combinations can be temperature 180 ℃.
Ordinary straight seam steel pipe for use in harsh environmental conditions, there will be severe corrosion, which will reduce the life of the steel pipe, anti-corrosion pipe insulation is relatively long service life, under normal circumstances can be used are 30-50 years or so, and the correct installation and use is also possible to make the pipe network maintenance costs low, corrosion pipe insulation can also set the alarm system, automatic leak detection pipe network failure, the exact knowledge of the fault location and automatically alarms.
Pipe insulation is widely used in the construction and promotion, and production technology constantly improve and popularize. Pipe insulation has a good performance can promote their use in a good range, different parts of the structure and cooperate with each other in use, play an important role and value. Polyurethane foam has good mechanical properties and thermal insulation properties, usually can be temperature 120 ℃, by modification or other insulating material combinations can be temperature 180 ℃.
Professional Skills of Straight Seam Double Submerged Arc Welded Steel Pipe
Professional Skills of Straight Seam Double Submerged Arc Welded Steel Pipe(lsaw steel pipe)
1, Double submerged arc welding method in a new invention in 1940, in front of it and the manual welding the same place that it still uses residue protection, but this is not the dregs electrode coating. Straight seam double submerged arc welding and manual welding the same place that it still uses residue protection, but this is not the dregs electrode coating, specifically melting out of the flux. Flux The flux system consists of a funnel filled through a pipeline to be welded to the front.
2. The second difference is the use of electrode using wire, because wire can be continuously sent; electrodes, we burn a welding electrode must have a head gave threw it, and the operation had to stop, and then change the electrode welding.
3. In this way, the first advantage is fully automated; second advantage, which is under the submerged arc welding, so its heat exchange and protection of relatively strong performance, high quality weld out; third advantage, since the automatic submerged arc welding arc buried under welding flux, so it can use high-current, high welding efficiency, the recent progress of our country natural gas pipeline project.
4, Later changed to the wire, with the wire feed unit and wire spool is continuously sent to the wire, the welding wire is continuously fed, igniting an arc in the meltable particulate flux covering, welding wire, part of the melting and evaporation of the base metal and solder forms a cavity, the arc is stabilized combustion cavity inside, so call it submerged arc welding. Arc is buried in the inside of the cavity.
5, The pipe is a high-strength steel, such pipelines in the factory inside the first preformed section, and then get on the site, in the field of welding, the welding process such pipelines in factory production is the use of submerged arc welding, now buried welding has developed into, a double wire submerged arc welding, as well as multi-wire submerged arc welding, to further improve efficiency.
1, Double submerged arc welding method in a new invention in 1940, in front of it and the manual welding the same place that it still uses residue protection, but this is not the dregs electrode coating. Straight seam double submerged arc welding and manual welding the same place that it still uses residue protection, but this is not the dregs electrode coating, specifically melting out of the flux. Flux The flux system consists of a funnel filled through a pipeline to be welded to the front.
2. The second difference is the use of electrode using wire, because wire can be continuously sent; electrodes, we burn a welding electrode must have a head gave threw it, and the operation had to stop, and then change the electrode welding.
3. In this way, the first advantage is fully automated; second advantage, which is under the submerged arc welding, so its heat exchange and protection of relatively strong performance, high quality weld out; third advantage, since the automatic submerged arc welding arc buried under welding flux, so it can use high-current, high welding efficiency, the recent progress of our country natural gas pipeline project.
4, Later changed to the wire, with the wire feed unit and wire spool is continuously sent to the wire, the welding wire is continuously fed, igniting an arc in the meltable particulate flux covering, welding wire, part of the melting and evaporation of the base metal and solder forms a cavity, the arc is stabilized combustion cavity inside, so call it submerged arc welding. Arc is buried in the inside of the cavity.
5, The pipe is a high-strength steel, such pipelines in the factory inside the first preformed section, and then get on the site, in the field of welding, the welding process such pipelines in factory production is the use of submerged arc welding, now buried welding has developed into, a double wire submerged arc welding, as well as multi-wire submerged arc welding, to further improve efficiency.
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