A double-layer medium frequency heating inductor

Abstract

The utility model provides a double-layer medium frequency heating inductor, wherein the first layer of the double-layer medium frequency heating inductor is a heating coil, and the second layer is a cooling coil; the heating coil is energized for medium frequency heating, and the cooling coil is sprayed with water for water cooling; compared with the prior art, the utility model can control the temperature difference between the inner and outer walls of the composite elbow during bending and after cooling to below 25°C, and the surfacing layer of the inner layer of the produced elbow will not crack.

Description

Technical Field

[0001] The utility model belongs to the field of medium frequency pipe bending, and specifically relates to a double-layer medium frequency heating inductor. Background Art

[0002] Medium frequency pipe bending is to put a medium frequency induction coil on the part of the steel pipe to be bent after cutting the straight pipe, clamp the pipe head with a mechanical rotating arm, and pass a medium frequency current into the induction coil to heat the steel pipe. When the temperature of the steel pipe rises to the plastic state, the rear end of the steel pipe is pushed forward with mechanical thrust to bend it. The bent steel pipe part is quickly cooled with a coolant. In this way, the pipe is continuously bent while heating, pushing, bending, and cooling. Medium frequency pipe bending is mainly used in many industries such as building arc steel structures, tunnel supports, roof curved beams, subway projects, aluminum doors and windows, ceilings, cylindrical inner skeletons, balcony handrails, shower room doors, production line tracks, fitness equipment, etc.

[0003] For pipelines in special environments or for special purposes, composite pipes made of multiple materials can be used. For example, in the field of oil and gas, since oil and gas contain a large amount of corrosive media, corrosion-resistant alloys such as nickel-based alloys can be welded on the inner wall for corrosion protection. Utility model patent CN107775280B discloses a method for manufacturing a composite elbow made of N08825 nickel-based alloy, by which a composite elbow with strong corrosion resistance can be obtained.

[0004] However, the manufacturing method in the above patent can only be used to manufacture thinner wall composite pipe bends. In 2024, our company undertook the production of thick-walled nickel-based composite pipe bends from Suzhou Wilhelm Welding Technology Co., Ltd. This kind of thick-walled nickel-based welded composite pipe is used for deep-sea oil and gas transportation on the seabed of the west coast of the United States. Natural gas is mined at a water depth of about 3,000 meters. The pressure on the pipeline is relatively large, so a larger wall thickness is required. The steel pipe layer is 28.58 mm thick and the welded layer is 3.6 mm thick. If the existing composite pipe bending method is used, the temperature of the composite bend is uneven during heating, the temperature difference between the inner and outer walls of the pipe is large, and the temperature of the inner wall is low. The nickel-based alloy welded layer on the inner wall is prone to cracking during bending. Utility Model Content

[0005] In order to solve the above problems, the utility model provides a double-layer medium frequency heating inductor.

[0006] The purpose of the utility model is achieved in the following ways:

[0007] A double-layer medium frequency heating inductor, characterized in that the first layer of the double-layer medium frequency heating inductor is a heating coil (1), and the second layer is a cooling coil (2); the heating coil (1) is energized to perform medium frequency heating, and the cooling coil (2) is sprayed with water to perform water cooling.

[0008] In the double-layer medium frequency heating inductor, the heating coil (1) is a hollow copper tube with a width of 50 mm, a thickness of 25 mm and a wall thickness of 5 mm.

[0009] In the double-layer medium frequency heating inductor, the cooling ring (2) is a hollow copper tube with a width of 15 mm, a thickness of 15 mm and a wall thickness of 2.5 mm; water spray holes (3) are arranged on the cooling ring, and the water spray holes (3) have a diameter of 1.5 mm and a spacing of 20 mm.

[0010] Compared with the prior art, the utility model can control the temperature difference between the inner and outer walls of the composite bent pipe during bending and after cooling to below 25° C., and the cladding layer of the inner layer of the produced bent pipe will not crack. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A front view of a double-layer medium frequency heating inductor of the utility model.

[0012] Figure 2 First page of the visual inspection report

[0013] Figure 3 Page 2 of the visual inspection report

[0014] Figure 4 The first page of the ultrasonic test report

[0015] Figure 5 The second page of the ultrasonic test report

[0016] Figure 6 Ultrasonic testing diagram

[0017] Figure 7 The first page of the magnetic particle inspection report

[0018] Figure 8 The second page of the magnetic particle inspection report

[0019] Fig. 9 Magnetic particle testing diagram

[0020] Fig.10 The first page of the penetration test report

[0021] Fig.11 Page 2 of the penetration test report

[0022] Fig.12 Schematic diagram of penetration testing

[0023] Fig.13 One of the photos of the cracked inner wall of thick-walled composite elbow

[0024] Fig.14 Photo 2 of the cracked inner wall of a thick-walled composite elbow

[0025] Fig.15This is a photo of the inner wall of the thick-walled composite elbow without cracks produced by the utility model.

[0026] Fig.16 Photo 2 of the inner wall of the thick-walled composite elbow without cracks produced by the utility model DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0028] In the present utility model, unless otherwise expressly specified and limited, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model.

[0029] A method for manufacturing a thick-walled nickel-based cladding composite pipe bend, wherein the wall thickness of the composite pipe is more than 30 mm, the composite pipe is bent after being heated, and the temperature difference between the inner wall and the outer wall during bending is less than 25°C; after bending, the composite pipe is cooled, and the temperature difference between the inner wall and the outer wall after cooling is less than 25°C. The temperature difference between the inner wall and the outer wall is small, and the cladding layer on the inner wall of the bent pipe is not easy to crack. At the same time, since the outer layer of the composite pipe is a steel pipe and the inner layer is a nickel-based alloy, the thermal properties and mechanical properties of the two layers are different, and the selection of the temperature can take into account the performance of the inner and outer layers, and achieve a better bending effect.

[0030] In the manufacturing method of a thick-walled nickel-based cladding composite elbow pipe, the composite pipe is heated by a double-layer medium-frequency heating inductor. The double-layer medium-frequency heating inductor used in the method is the double-layer medium-frequency heating inductor of the utility model.

[0031] The thick-walled nickel-based cladding composite elbow manufacturing method is characterized in that the cooling method is water cooling.

[0032] The thick-walled nickel-based cladding composite pipe bending manufacturing method has the following characteristics: when bending the pipe, the outer wall heating temperature is 950°C, the inner wall cladding layer temperature is 930°C; after cooling, the outer layer temperature of the pipe is 550°C, the inner layer temperature of the pipe is 570°C, and the advancing speed is 22.5-27.5mm / min

[0033] Since the composite elbow of the present application is used for deep-sea oil and gas transportation, high mechanical property requirements are imposed on the outer layer and the cladding layer of the elbow. Therefore, quenching and tempering are required after the elbow is bent. The quenching process is as follows:

[0034] Heat the heating furnace freely to 400℃, then heat it to 850℃ at a rate of 80-200℃ / H, and put the workpiece in; after putting the workpiece in, continue to heat it to 950℃ at a rate of 80-200℃ / H, and then keep it warm; the insulation temperature is 950℃, the insulation time is 54min, and then cool it after insulation; the cooling method is water cooling, the upper limit temperature of the cooling water tank is 40℃, and the time from the workpiece leaving the furnace to entering the water is ≤70s; the quenching time is ≥10min.

[0035] The thick-walled nickel-based cladding composite elbow manufacturing method is described, wherein the composite elbow is tempered after quenching, and the tempering process is as follows:

[0036] Heat the heating furnace freely to 400℃, then heat it to 650℃ at a rate of 80-200℃ / H, then put the workpiece in for insulation; insulation temperature is 650℃, insulation time is 120min, and cooling is carried out after insulation; cooling method: cooling rate above 400℃ is 70-200℃ / H, and cooling in still air when below 400℃.

[0037] A double-layer medium frequency heating inductor is used for the above-mentioned thick-walled nickel-based cladding composite elbow; the first layer of the double-layer medium frequency heating inductor is a heating coil 1, and the second layer is a cooling coil 2; the heating coil 1 is powered on for medium frequency heating, and the cooling coil 2 is sprayed with water for water cooling.

[0038] The double-layer medium frequency heating inductor is characterized in that the heating coil is a hollow copper tube with a width of 50 mm, a thickness of 25 mm, and a wall thickness of 5 mm. Water is passed through the hollow tube for cooling to prevent the heating coil from burning.

[0039] The double-layer medium frequency heating inductor, the cooling ring is a hollow copper tube with a width of 15mm, a thickness of 15mm, and a wall thickness of 2.5mm; a water spray hole 3 is arranged on the cooling ring, the water spray hole 3 has a diameter of 1.5mm, a spacing of 20mm, a cooling water temperature of 15-45°C, and a water pressure of 0.163-0.173MPa.

[0040] The traditional medium frequency induction heating coil is a hollow copper tube, which is heated by induction when electricity is supplied, and water is passed through the hollow tube, and then cooled after being sprayed out. When this heating coil is used for heating, the temperature difference between the inner and outer walls of the bent composite tube is large, and the inner wall cladding layer is prone to cracking. The heating coil of this application separates heating and cooling, such as Figure 1 This is the front view of the double-layer medium-frequency heating sensor of this application, 1 is the heating coil, 2 is the cooling coil, 3 is the water spray hole, 4 is the cooling coil water inlet, 5 is the cooling coil water outlet, 6 is the copper tube, 7 is the fixing plate, 8 is the heating coil water inlet, and 9 is the heating coil water outlet. Compared with the old one, the width of the new heating coil is increased from 25mm to 50mm, and the thickness is increased from 15mm to 25mm, so that the heating time is longer, the temperature rise of the inner and outer walls of the thick-walled cladding composite bent pipe is more uniform, and the temperature difference is less than 25℃ when bending the pipe; the cooling speed can be reduced during cooling, and the cooling of the inner and outer layers is more uniform. After cooling with cooling water, the temperature difference of the inner and outer walls is also less than 25℃.

[0041] Example:

[0042] The nickel-based cladding composite pipe is 2.121m long and 32.17mm thick, of which the cladding layer is 3.6mm and the steel pipe layer is 28.58mm. The double-layer medium-frequency inductor is used for heating and bending, with a pushing speed of 26mm / min, a pushing time of 51min, a bending angle of 90 degrees, and a bending radius of 0.8415m.

[0043] After bending, the steel pipe is cooled by water sprayed from the cooling ring of the double-layer intermediate frequency sensor, with a water temperature of 28°C and a water pressure of 0.17MPa.

[0044] After water cooling, let it stand for 240 minutes until it reaches 30°C, and then quench it.

[0045] During quenching, the heating furnace is first heated up to 400℃ freely, then heated up to 850℃ at a rate of 180℃ / H, and the workpiece is placed; after the workpiece is placed, the temperature is continued to be raised to 950℃ at a rate of 150℃ / H, and then kept warm; the holding temperature is 950℃, the holding time is 54min, and then cooled; the cooling method is water cooling, the cooling water temperature is 28℃, and the time from the workpiece leaving the furnace to entering the water is 45s; the quenching time is 20min. Tempering is performed after quenching.

[0046] During tempering, the heating furnace is first heated freely to 400℃, then heated to 650℃ at a rate of 120℃ / H, and then the workpiece is placed for heat preservation; the heat preservation temperature is 650℃, the heat preservation time is 120min, and then cooled; cooling method: the cooling rate above 400℃ is 120℃ / H, and the furnace is cooled in still air below 400℃. After cooling, a thick-walled nickel-based cladding composite elbow with no cracking of the cladding layer is obtained.

[0047] Figure 2-Figure 12This is the inspection report and inspection schematic diagram of the thick-walled nickel-based alloy welded composite bent pipe produced by the method described in this application. The inspection includes visual inspection, ultrasonic inspection, magnetic particle inspection, and penetration inspection. All inspections did not detect defects in the inner weld layer, that is, all thick-walled nickel-based alloy welded composite bent pipes did not have cracks.

[0048] Figure 13-14 This is a photo of the inner wall of a cracked thick-walled composite elbow. The dark spots in the picture are cracks. Figure 15-16 This is a photo of the inner wall of the thick-walled composite elbow produced for the utility model, and there is no cracking.

[0049] The above is only a preferred embodiment of the present invention. It should be pointed out that those skilled in the art can make several changes and improvements without departing from the overall concept of the present invention, and these should also be regarded as the protection scope of the present invention.

Claims

1. A double-layer medium frequency heating inductor, characterized in that: The first layer of the double-layer medium frequency heating inductor is a heating coil (1), and the second layer is a cooling coil (2); the heating coil (1) is energized to perform medium frequency heating, and the cooling coil (2) is sprayed with water to perform water cooling.

2. A double-layer medium frequency heating inductor as claimed in claim 1, characterized in that: The heating ring (1) is a hollow copper tube with a width of 50 mm, a thickness of 25 mm and a wall thickness of 5 mm.

3. A double-layer medium frequency heating inductor as claimed in claim 2, characterized in that: The cooling ring (2) is a hollow copper tube with a width of 15 mm, a thickness of 15 mm, and a wall thickness of 2.5 mm. Water spray holes (3) are provided on the cooling ring. The water spray holes (3) have a diameter of 1.5 mm and a spacing of 20 mm.

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