Induction welding device and method for metal composite pipe

Abstract

The present invention provides an induction welding device for metal composite pipes, including a first coil group and a second coil group. In the first coil group, the mounting ends of the first heating coil and the infrared camera are respectively connected to the fixed end of the first support frame. In the second coil group, the mounting end of the sliding platform and the second mounting end of the second support frame are slidably connected, the stepper motor is connected to the lead screw, the output end of the lead screw is connected to the first end of the sliding platform, the fixed ends of the magnetic conductor and the second heating coil are respectively connected to the mounting ends of the support, the two ends of the stud are respectively connected to the third mounting ends of the support symmetrically distributed on both sides of the adapter plate through nuts, and the mounting end of the thick stud passes through the mounting hole of the adapter plate and is connected to the second end of the sliding platform through the thick nut. The induction welding method of the present invention adjusts the distance between the electrode groups and the power of each electrode through temperature feedback to achieve dynamic balance during the production process, so that each layer of metal in the composite pipe processing can maintain a different suitable welding temperature.

Description

Technical Field

[0001] The invention relates to the technical field of composite pipe production, and in particular to an induction welding device and an induction welding method for metal composite pipes. Background Art

[0002] Metal composite pipes have been widely used in the fields of petroleum, chemical fuels, deep-sea energy transportation, etc. Different metal materials can be used on the outside to cope with the corrosion of the environment and internal chemical liquids, while the center material of the pipe can maintain overall rigidity and strength. Compared with the use of pure metal one-piece processing, composite pipes can improve product performance, but due to the different properties of different layers of metal in composite pipes, the high processing requirements have limited the development of composite pipes. However, with the development of new materials and computer control, the future prospects of high-quality metal composite pipes are broad.

[0003] The difficulty of metal composite pipes lies in how to reliably bond several layers of different metal materials together. The existing technology produces pipe joints through mechanical composite methods, which are prone to delamination and failure. Hot-rolled composite plates are currently difficult to weld into steel pipes. There are currently some devices that produce pipes through induction heating, such as the publication number CN 113245756A, a double-layer composite pipe straight seam welding heating device and its process, which uses multiple electrodes to heat the pipe blank separately to solve the different temperatures required by different materials, but the coil layout is limited and it is difficult to deal with three-layer or other forms of composite pipes. Therefore, the present invention proposes an induction welding method and device for metal composite pipes. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides an induction welding device and method for a metal composite pipe. A first coil group is arranged at the final welding point of the pipe, and multiple second coil groups are set to heat the inner side of the pipe before the pipe is bent and rolled. Therefore, by separately adjusting the power P1 of the first heating coil and the power P2 of the second heating coil, different heating can be achieved when the material properties inside and outside the composite pipe are different. Temperature feedback is used to adjust the distance between the coil groups and the power of each heating coil to achieve dynamic balance in the production process, so that each layer of metal in the composite pipe maintains a different suitable welding temperature, thereby solving the problem of difficulty in welding due to different heating target temperatures.

[0005] The present invention provides an induction welding device for metal composite pipes, which includes a first coil group, a second coil group, an extrusion roller, a high-frequency power supply, a feeding mechanism and a circulating water pump. Along the length direction of the substrate, the extrusion roller, the first coil group, the second coil group and the feeding mechanism are distributed in sequence, the high-frequency power supply is located on one side of the second coil group, and the high-frequency power supply is connected to the circulating water pump. The first coil group includes a first heating coil, a first support frame, an infrared camera, a data line, a water-cooled copper tube and a controller, the mounting ends of the first heating coil and the infrared camera are respectively connected to the first fixed end and the second fixed end of the first support frame, the output end of the infrared camera is connected to the controller through the data line, and the power supply end of the first heating coil is connected to the first output end of the high-frequency power supply through the water-cooled copper tube. The second coil group includes a stepper motor, a lead screw, a water pipe, a flexible wire, a stud, a nut, a guide rail, a magnet, a second heating coil, a connecting copper tube, a transfer tube, a thick stud, a sliding platform, a thick nut, a second support frame, an adapter plate and a support. The fixed end of the stepper motor is connected to the first mounting end of the second support frame, the mounting end of the sliding platform is slidably connected to the second mounting end of the second support frame, the output end of the stepper motor is connected to the input end of the lead screw, the output end of the lead screw is connected to the first end of the sliding platform, the first end of the water pipe and the flexible wire are respectively connected to the second output end and the third output end of the high-frequency power supply, the second end of the water pipe and the flexible wire are respectively connected to the first end and the second end of the second heating coil through the sliding platform, the transfer tube and the mounting holes of the connecting copper tube, the transfer tube is located between the sliding platform and the adapter plate, and the connecting copper tube is located between the adapter plate and the support. The fixed ends of the magnetic conductor and the second heating coil are respectively connected to the first mounting end and the second mounting end of the support, the two ends of the stud are respectively connected through nuts and the third mounting end of the support symmetrically distributed on both sides of the adapter plate, and the mounting end of the thick stud passes through the mounting hole of the adapter plate and is connected to the second end of the sliding platform through a thick nut; by separately adjusting the power of the first heating coil or the power of the second heating coil, the differential heating when the material properties inside and outside the metal composite pipe are different can be improved.

[0006] Preferably, the mounting ends of the first coil group, the second coil group, the extrusion roller, the high-frequency power supply, the feeding mechanism and the circulating water pump are respectively connected to the first mounting end, the second mounting end, the third mounting end, the fourth mounting end, the fifth mounting end and the sixth mounting end of the substrate.

[0007] Preferably, the first coil group is located outside the pipeline, and the second coil group is located inside the pipeline.

[0008] Preferably, the number of the first coil group is one, and the number of the second coil group is at least one.

[0009] Preferably, the magnetic conductor and the second heating coil are respectively located on both sides of the pipeline wall, the magnetic conductor is located on the outer surface of the pipeline wall, and the second heating coil is located on the inner surface of the pipeline wall.

[0010] Another aspect of the present invention provides an induction welding method for the induction welding device of the above-mentioned metal composite pipe, and the specific steps include:

[0011] S1. Determine the number n of the second coil group according to the requirements of the pipeline to be produced, and adjust the positions of the thick studs and studs in the second coil group so that the second heating coil in the second coil group reaches the corresponding position, and fix the first coil group above the pipeline welding position;

[0012] S2, determining the material properties of the plate required in the pipeline to be produced, and setting the heating power P1 of the first heating coil and the heating power P2 of the second heating coil through a high-frequency power supply;

[0013] S3, according to the first thermal diffusion time t1 required for the inner plate after the plurality of second coil groups are heated and the second thermal diffusion time t2 required for the outer plate after the first second coil group is heated, respectively adjust the first spacing L1 between the first coil group and the first second coil group and the second spacing L2 between the plurality of second coil groups, so as to obtain the initial spacing of the device, wherein the expression of the first thermal diffusion time t1 is:

[0014] t1=K / (nP2)

[0015] Where K is the proportionality coefficient;

[0016] The expression of the second thermal diffusion time t2 is:

[0017] t2=K / P2

[0018] Where K is the proportionality coefficient;

[0019] S4, based on step S3, respectively adjusting the first distance L1 between the first coil group and the second coil group and the second distance L2 between adjacent second coil groups, so that the temperature required for the pipe to be produced during the heating and welding process is more uniform;

[0020] S5, respectively set the temperature interval C2 of the inner plate and the temperature interval C1 of the outer plate, and start production by the feeding mechanism, so that the pipe to be produced is sent to the second coil group and the first coil group for heating through the feeding mechanism at the plate and strip forward speed V; if the plate and strip forward speed V changes, proceed to step S3, if the plate and strip forward speed V does not change, proceed to step S6;

[0021] S6. Compare the temperature values ​​of the inner plate and the outer plate collected by the infrared camera with the temperature interval C2 of the inner plate and the temperature interval C1 of the outer plate respectively. If the temperature value of the outer plate is higher than the temperature interval C1 of the outer plate, reduce the heating power P1 of the first heating coil and return to step S2. If the temperature value of the outer plate is lower than the temperature interval C1 of the outer plate, increase the heating power P1 of the first heating coil and return to step S2. If the temperature value of the inner plate is higher than the temperature interval C2 of the inner plate, reduce the heating power P2 of the second heating coil and return to step S2. If the temperature value of the inner plate is lower than the temperature interval C2 of the inner plate, increase the heating power P2 of the second heating coil and return to step S2. If the temperature value of the outer plate and the temperature value of the inner plate are respectively located in the temperature interval C1 of the outer plate and the temperature interval C2 of the inner plate, the temperature adjustment of the inner and outer plates before welding is completed.

[0022] Preferably, in step S2, the material properties of the required plate include the thickness H1 of the inner plate, the thermal conductivity λ1 of the inner plate, the thickness H2 of the outer plate, and the thermal conductivity λ2 of the outer plate.

[0023] Preferably, the heating power P1 of the first heating coil and the heating power P2 of the second heating coil are respectively related to the thickness H1 of the inner plate, the thermal conductivity λ1 of the inner plate, the thickness H2 of the outer plate and the thermal conductivity λ2 of the outer plate.

[0024] Preferably, in step S3, the proportionality coefficient K is proportional to the thickness H of the plate and inversely proportional to the thermal conductivity λ.

[0025] Preferably, in step S3, the first distance L1 is expressed as:

[0026] L1=V×t1

[0027] Wherein, V is the production speed of the plate;

[0028] The expression of the second distance L2 is:

[0029] L2=V×t2

[0030] Wherein, V is the production speed of the plate.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1. The present invention adopts different coils for heating the inner and outer sides of the metal composite pipe. Since the optimal welding temperature of each layer of the composite pipe is different, the first coil group is controlled to heat the outer side, and the second coil group is controlled to heat the inner side. The power of the coils is controlled separately, so that different materials have their own suitable welding temperatures during extrusion welding.

[0033] 2. The device of the present invention introduces speed and temperature feedback regulation to change the power on the coil and the distance between the electrode groups at the same time, so that the temperature will not be too high or too low due to environmental interference, thereby improving the temperature stability in the welding area.

[0034] 3. The method of the present invention achieves precise heating of the pipeline through the inner and outer induction electrodes. The temperature is transferred from the inner and outer pipe walls to the center of the weld, and the temperature gradient in the wall thickness direction is reduced.

[0035] 4. Compared with the traditional processing method, the present invention not only does not require additional additives, but also does not produce residual waste, and the energy utilization is concentrated, which is more environmentally friendly; and the production process of the present invention uses precise electrode heating, so the production is more efficient and energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a flow chart of the induction welding method for metal composite pipes of the present invention;

[0037] Figure 2 The figure is an overall structural diagram of the induction welding device for metal composite pipe of the present invention;

[0038] Figure 3 A top view of an induction welding device for metal composite pipes according to the present invention;

[0039] Figure 4 A partial view of a first coil in an induction welding device for a metal composite pipe according to the present invention;

[0040] Figure 5 A partial view of a second coil in an induction welding device for a metal composite pipe according to the present invention;

[0041] Figure 6a and Figure 6b They are respectively temperature comparison diagrams of the three-layer metal composite pipe in the axial cross section in the induction welding method for the metal composite pipe of the present invention.

[0042] Main reference numerals:

[0043] Pipeline 0, inner plate 01, center layer 02, outer plate 03, first coil group 100, first heating coil 101, first support frame 102, infrared camera 103, data cable 104, water-cooled copper tube 105, controller 106, second coil group 200, stepper motor 201, lead screw 202, water pipe 203, flexible wire 204, stud 206, nut 205, guide rail 207, magnetic conductor 208, second heating coil 209, connecting copper tube 210, transfer tube 211, thick stud 212, sliding platform 213, thick nut 214, substrate 3, extrusion roller 4, high-frequency power supply 5, feeding mechanism 6, circulating water pump 7. DETAILED DESCRIPTION

[0044] In order to fully describe the technical content, structural features, objectives and effects of the present invention, the following will be described in detail with reference to the accompanying drawings.

[0045] Induction welding devices for metal composite pipes, such as Figure 2 and Figure 3 As shown, it includes a first coil group 100, a second coil group 200, an extrusion roller 4, a high-frequency power supply 5, a feeding mechanism 6 and a circulating water pump 7, which are supported on the pipeline production line as a whole, and the device is placed on the substrate 3 as a whole. The pipeline 0 is fed by the feeding mechanism 6 to the extrusion roller 4 for bending and extrusion forming. In this process, the pipeline 0 is heated by the second coil group 200 and the first coil group 100 successively. After each layer of the composite plate reaches the required welding temperature, it is extruded and welded. The first coil group 100 and the second coil group 200 are both powered by the high-frequency power supply 5. The first coil group 100 is arranged at the final welding point, and the second coil group 200 contains multiple groups of coils. Therefore, the power P1 of the first heating coil 101 and the power P2 of the second heating coil 209 can be adjusted separately to deal with the different heating when the material properties inside and outside the composite pipe are different.

[0046] like Figure 3 As shown, along the length direction of the substrate 3, the extrusion roller 4, the first coil group 100, the second coil group 200 and the feeding mechanism 6 are sequentially distributed, the high-frequency power supply 5 is located on one side of the second coil group 200, and the high-frequency power supply 5 is connected to the circulating water pump 7. Specifically, the mounting ends of the first coil group 100, the second coil group 200, the extrusion roller 4, the high-frequency power supply 5, the feeding mechanism 6 and the circulating water pump 7 are respectively connected to the first mounting end, the second mounting end, the third mounting end, the fourth mounting end, the fifth mounting end and the sixth mounting end of the substrate 3.

[0047] The first coil group 100 is located above the outer side of the pipeline 0 and is used to heat the outer side of the pipeline 0. Each time the heating is performed, the temperature of the outer side is higher than that of the inner side. Figure 4As shown, it includes a first heating coil 101, a first support frame 102, an infrared camera 103, a data line 104, a water-cooled copper tube 105 and a controller 106. The first heating coil 101 is covered with a magnetic conductor. The infrared camera 103 is aimed at the welding part of the pipeline 0 to collect the temperature of each layer of the plate strip. The power supply of the first heating coil 101 is completed through the water-cooled copper tube 105. The infrared camera 103 is used as a temperature sensor to collect temperature values ​​and feed them back to the controller 106. After processing, the controller 106 returns the power signal to the high-frequency power supply 5.

[0048] The mounting ends of the first heating coil 101 and the infrared camera 103 are respectively connected to the first fixed end and the second fixed end of the first support frame 102, the output end of the infrared camera 103 is connected to the controller 106 via the data line 104, and the power supply end of the first heating coil 101 is connected to the first output end of the high-frequency power supply 5 via the water-cooled copper tube 105.

[0049] The second coil group 200 is located on the inner side of the heating pipe 0 before the pipe 0 is bent and rolled. Figure 5 As shown, it includes a stepper motor 201, a lead screw 202, a water pipe 203, a flexible wire 204, a stud 206, a nut 205, a guide rail 207, a magnet 208, a second heating coil 209, a connecting copper tube 210, a transfer tube 211, a thick stud 212, a sliding platform 213, a thick nut 214, a second support frame, a transfer plate and a support. The induction heating process of the second coil group 200 is heated by the magnetic field generated between the second coil 209 and the magnet 208. The second heating coil 209 is placed on the inner side of the pipe 0. The eddy current of the inner pipe is greater than that of the outer side. Therefore, the temperature of the inner side is higher than that of the outer side each time heating is performed. The cooling water of the second coil group 200 flows in and out of the water pipe 203 through the connecting copper tube 210 to the transfer tube 211. The lateral distance of the second heating coil 209 is limited by the stud 206 and the nut 205 thereon, and the vertical distance is limited by the thick stud 212 and the thick nut 214. During the movement, the water pipe 203 and the flexible wire 204 are made of flexible materials.

[0050] The fixed end of the stepper motor 201 is connected to the first mounting end of the second support frame, the mounting end of the sliding platform 213 is slidably connected to the second mounting end of the second support frame, the output end of the stepper motor 201 is connected to the input end of the lead screw 202, the output end of the lead screw 202 is connected to the first end of the sliding platform 213, the rotation of the stepper motor 201 can drive the second heating coil 209 to move along the axial direction of the pipeline 0 with the sliding platform 213, the first ends of the water pipe 203 and the flexible wire 204 are respectively connected to the second output end and the third output end of the high-frequency power supply 5, the second ends of the water pipe 203 and the flexible wire 204 are respectively connected to the first end and the second end of the second heating coil 209 through the mounting holes of the sliding platform 213, the adapter tube 211 and the connecting copper tube 210, the adapter tube 211 is located between the sliding platform 213 and the adapter plate, and the connecting copper tube 210 is located between the adapter plate and the support.

[0051] The fixed ends of the magnetic conductor 208 and the second heating coil 209 are respectively connected to the first mounting end and the second mounting end of the support, the two ends of the stud 206 are respectively connected to the third mounting end of the support symmetrically distributed on both sides of the adapter plate through the nut 205, and the mounting end of the thick stud 212 passes through the mounting hole of the adapter plate and is connected to the second end of the sliding platform 213 through the thick nut 214; by separately adjusting the power of the first heating coil 101 or the power of the second heating coil 209, the differential heating when the material properties inside and outside the metal composite pipe are different can be improved.

[0052] In a preferred embodiment of the present invention, the number of the first coil group 100 is one, the number of the second coil group 200 is at least one, and the number of the second coil group 200 is determined according to the material properties of the pipe 0 to be processed. The magnetic conductor 208 and the second heating coil 209 are respectively located on both sides of the pipe wall, the magnetic conductor 208 is located on the outer surface of the pipe wall, and the second heating coil 209 is located on the inner surface of the pipe wall.

[0053] Furthermore, since the second heating coil 209 is located in a small space, it is difficult for a single pair of the second heating coil 209 to heat to the required high temperature at one time. Multiple groups of second heating coils 209 and corresponding second support frames are arranged in the axial direction to share the concentrated current on the single second heating coil 209, and make the heating more uniform. When the wall thickness of the heating pipe 0 is less than 10mm, one group of second coil groups 200 is required, when the wall thickness of the heating pipe 0 is 10-20mm, two groups of second coil groups 200 are required, and when the wall thickness of the heating pipe 0 is more than 30mm, in order to heat evenly, three or more second coil groups 200 need to be arranged.

[0054] The second aspect of the present invention provides an induction welding method for the induction welding device of the metal composite pipe of the present invention, which adjusts the distance between the coil groups and the power of each heating coil through temperature feedback to achieve dynamic balance in the production process, and maintains different suitable welding temperatures for each layer of metal in the composite pipe. This realizes the induction welding production of metal composite pipes and solves the problem of difficulty in welding due to different heating target temperatures. The specific steps include:

[0055] S1. According to the requirements of the pipe 0 to be produced, the number n of the second coil group 200 is determined, and the position of the second heating coil 209 in the second coil group 200 is adjusted by rotating the positions of the stud 206 and the thick stud 212 in the second coil group 200, so that the second heating coil 209 is close to the heating surface of the pipe 0, and the first coil group 100 is fixed above the welding position of the pipe 0.

[0056] S2, determining the material properties of the plate material required in the pipeline 0 to be produced, and setting the heating power P1 of the first heating coil 101 and the heating power P2 of the second heating coil 209 through the high-frequency power supply 5.

[0057] Specifically, the material properties of the required plate include the thickness H1 of the inner plate, the thermal conductivity λ1 of the inner plate, the thickness H2 of the outer plate, and the thermal conductivity λ2 of the outer plate.

[0058] The magnitudes of the heating power P1 of the first heating coil 101 and the heating power P2 of the second heating coil 209 are respectively related to the thickness H1 of the inner plate, the thermal conductivity λ1 of the inner plate, the thickness H2 of the outer plate and the thermal conductivity λ2 of the outer plate.

[0059] S3, according to the first thermal diffusion time t1 required for the inner plate after the plurality of second coil groups 200 are heated and the second thermal diffusion time t2 required for the outer plate after the first second coil group 200 are heated, the first spacing L1 between the first coil group 100 and the first second coil group 200 and the second spacing L2 between the plurality of second coil groups 200 are adjusted respectively, so as to obtain the initial spacing of the device, and the expression of the first thermal diffusion time t1 is:

[0060] t1=K / (nP2)

[0061] Among them, K is the proportionality coefficient, which is proportional to the thickness H of the plate and inversely proportional to the thermal conductivity λ;

[0062] The expression of the second thermal diffusion time t2 is:

[0063] t2=K / P2

[0064] Among them, K is the proportionality coefficient, which is proportional to the thickness H of the plate and inversely proportional to the thermal conductivity λ;

[0065] The expression of the first distance L1 is:

[0066] L1=V×t1

[0067] Wherein, V is the production speed of the plate;

[0068] The expression of the second spacing L2 is:

[0069] L2=V×t2

[0070] Wherein, V is the production speed of the plate.

[0071] S4. On the basis of step S3, the first spacing L1 between the first coil group 100 and the second coil group 200 and the second spacing L2 between adjacent second coil groups 200 are adjusted respectively, so that the temperature required for the pipe 0 to be produced during the heating and welding process is more uniform, thereby improving the heating efficiency.

[0072] S5. Set the temperature interval C2 of the inner plate and the temperature interval C1 of the outer plate respectively, and start production by the feeding mechanism 6, so that the pipe 0 to be produced is sent to the second coil group 200 and the first coil group 100 for heating through the feeding mechanism 6 at the plate strip forward speed V; if the plate strip forward speed V changes, proceed to step S3, if the plate strip forward speed V does not change, proceed to step S6.

[0073] S6. Compare the temperature values ​​of the inner plate and the outer plate collected by the infrared camera 103 with the temperature interval C2 of the inner plate and the temperature interval C1 of the outer plate respectively. If the temperature value of the outer plate is higher than the temperature interval C1 of the outer plate, reduce the heating power P1 of the first heating coil 101 and return to step S2. If the temperature value of the outer plate is lower than the temperature interval C1 of the outer plate, increase the heating power P1 of the first heating coil 101 and return to step S2. If the temperature value of the inner plate is higher than the temperature interval C2 of the inner plate, reduce the heating power P2 of the second heating coil 209 and return to step S2. If the temperature value of the inner plate is lower than the temperature interval C2 of the inner plate, increase the heating power P2 of the second heating coil 209 and return to step S2. If the temperature value of the outer plate and the temperature value of the inner plate are respectively in the temperature interval C1 of the outer plate and the temperature interval C2 of the inner plate, continue production.

[0074] The following is a further description of an induction welding device and method for a metal composite pipe according to the present invention in conjunction with an embodiment:

[0075] In a preferred embodiment of the present invention, in order to cope with the corrosive environment and meet the requirements of overall structural strength and outer hardness, a three-layer metal composite pipe with a diameter of 600 mm and a thickness of 30 mm is produced, wherein the inner plate is a nickel-based alloy, the outer plate is a low-carbon steel, and the center layer is a No. 20 steel. The large-diameter pipe 0 is produced. In this welding, the thickness of the outer plate to the inner plate is 5 mm, 23 mm, and 2 mm, respectively. The thermal conductivity of low-carbon steel is 50 W / mk at room temperature, the thermal conductivity of nickel-based alloy is 11 W / mk at room temperature, and the thermal conductivity of No. 20 steel is 54 W / mk at room temperature. The production speed V is set at 60 mm / s, that is, 60 mm of pipe 0 is produced per second.

[0076] The operation process of the induction welding method for metal composite pipe in this specific embodiment is implemented as follows:

[0077] S1. According to the requirements of the pipe 0 to be produced, the number n of the second coil group 200 is determined, and the stud 206 and the thick stud 212 in each second coil group 200 are rotated in sequence, so that the second heating coil 209 and the magnet 208 are at different suitable widths and heights, and the first coil group 100 is fixed above the welding part of the pipe 0. At this time, the initial position adjustment is completed. The pipe on the production line is formed by bending and rolling the strip. The strip needs to keep a distance of 3-5mm between the coil and the strip at different positions. If it is too close, friction will easily damage the coil, and if it is too far, the heating efficiency will decrease.

[0078] S2. According to the heating temperature of the pipe 0 to be produced and the thickness of the pipe 0, the high-frequency power supply 5 is used to set the heating power of the first heating coil 101 to 150 KW and the heating power of the second heating coil 209 to 130 KW.

[0079] S3. According to the thickness H1 of the inner plate, the thermal conductivity λ1 of the inner plate, the thickness H2 of the outer plate and the thermal conductivity λ2 of the outer plate, it is obtained that the coefficient K is 60kw / s, the first thermal diffusion time required for the inner plate after the plurality of second coil groups 200 are heated is 3s, and the second thermal diffusion time required for the outer plate after the first second coil group 200 is heated is 0.5s, and the first spacing between the first coil group 100 and the first second coil group 200 is adjusted to 180mm, and the second spacing between the plurality of second coil groups 200 is adjusted to 30mm, thereby obtaining the initial spacing of the device.

[0080] S4. On the basis of step S3, the first spacing L1 between the first coil group 100 and the second coil group 200 and the second spacing L2 between adjacent second coil groups 200 are adjusted respectively by the stepping motor 201 and the lead screw 202, so that the temperature required for the pipe 0 to be produced during the heating and welding process is more uniform, thereby improving the heating efficiency.

[0081] S5. Set the temperature interval C2 of the inner plate to 1100°C and the temperature zone C1 of the outer plate to 1400°C respectively, and start production by the feeding mechanism 6. Make the pipe 0 to be produced bend and form continuously at the plate strip forward speed V through the multiple guide extrusion rollers on the feeding mechanism 6, and send it to the second coil group 200 and the first coil group 100 for heating. At the second coil group 200, the heat is transferred from the surface to the inside, and the temperature of the plate strip rises. At this time, the temperature of the inner plate is greater than that of the outer plate. At the first coil group 100, the temperature of the outer plate rises, and the temperature of the inner plate and the temperature of the center layer also rise to a certain extent. Finally, extrusion welding is performed.

[0082] If the strip forward speed V changes, step S3 is performed to increase or decrease the first spacing L1 between the first coil group 100 and the second coil group 200 and the second spacing L2 between adjacent second coil groups 200 by the stepper motor 201; if the strip forward speed V does not change, step S6 is performed.

[0083] S6. Compare the temperature values ​​of the inner plate and the outer plate collected by the infrared camera 103 with the temperature interval C2 of the inner plate and the temperature interval C1 of the outer plate respectively. If the temperature value of the outer plate collected by the infrared camera 103 is 1340°C, it means that the external heating power of the pipeline 0 is too low at this time. Adjust the power P1 of the first coil group 100 and increase P1 to 165KW. Similarly, adjust the power of the second coil group 200 inside.

[0084] The temperature is continuously monitored. If a temperature abnormality occurs, return to step S2 to adjust the power. Otherwise, continue until the production is finished.

[0085] like Figure 6a The prior art induction welding of metal composite pipes and Figure 6b Temperature comparison of the induction welded metal composite pipe in the axial section of the present invention, Figure 6a For existing technology, Figure 6bThe temperature distribution after heating in the present invention, the white and black colors in the figure represent different materials, a1 represents the temperature distribution curve that appears in the prior art, and a2 represents the temperature curve that appears in the present invention in accordance with the pipeline. Due to the skin effect, when the coil is heated as a whole in the prior art, the inner and outer surface temperatures of the pipeline 0 are higher, and the center temperature is lower. In addition, the welding temperatures required for the inner and outer plates of the composite pipeline are different during extrusion welding, which further increases the difficulty of welding. In the production of composite pipelines, the prior art methods not only cannot control the temperature of different layers of materials, but also have a large temperature difference in the thickness direction. After adopting the present invention, the outer plate 02 and the inner plate 01 are heated successively by the second coil group 200 and the first coil group 100. When the optimal welding temperatures of the inner plate and the outer plate are different, the temperature of the inner and outer sides can be adjusted specifically. At the same time, the center layer 03 with the lowest temperature is heated twice to reduce the temperature difference in the thickness direction.

[0086] The thickness and thermal conductivity of each layer of plate are very important for the welding of composite pipes. When the thickness is thin and the thermal conductivity of the material is high, the corresponding welding speed can be increased. When the material thickness is large or the thermal conductivity is low, the corresponding welding speed must be slowed down to obtain sufficient heating time.

[0087] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An induction welding method for a metal composite pipe, the induction welding method is based on an induction welding device for a metal composite pipe, the induction welding device comprises a first coil group, a second coil group, an extrusion roller, a high-frequency power supply, a feeding mechanism and a circulating water pump, characterized in that: The induction welding device is placed on the substrate as a whole. Along the length direction of the substrate, the extrusion roller, the first coil group, the second coil group and the feeding mechanism are sequentially distributed. The high-frequency power supply is located on one side of the second coil group. The high-frequency power supply is connected to the circulating water pump. The first coil group includes a first heating coil, a first support frame, an infrared camera, a data line, a water-cooled copper tube and a controller, wherein the mounting ends of the first heating coil and the infrared camera are respectively connected to the first fixed end and the second fixed end of the first support frame, the output end of the infrared camera is connected to the controller via the data line, and the power supply end of the first heating coil is connected to the first output end of the high-frequency power supply via the water-cooled copper tube; The second coil group includes a stepper motor, a lead screw, a water pipe, a flexible wire, a stud, a nut, a guide rail, a magnetic conductor, a second heating coil, a connecting copper tube, a transfer tube, a thick stud, a sliding platform, a thick nut, a second support frame, an adapter plate and a support, wherein the fixed end of the stepper motor is connected to the first mounting end of the second support frame, the mounting end of the sliding platform is slidably connected to the second mounting end of the second support frame, the output end of the stepper motor is connected to the input end of the lead screw, the output end of the lead screw is connected to the first end of the sliding platform, the first end of the water pipe and the flexible wire are respectively connected to the second output end and the third output end of the high-frequency power supply, the second end of the water pipe and the flexible wire are respectively connected to the first end and the second end of the second heating coil through the sliding platform, the transfer tube and the mounting holes of the connecting copper tube, the transfer tube is located between the sliding platform and the adapter plate, and the connecting copper tube is located between the adapter plate and the support; The fixed ends of the magnetic conductor and the second heating coil are respectively connected to the first mounting end and the second mounting end of the support, the two ends of the stud are respectively connected to the third mounting end of the support symmetrically distributed on both sides of the adapter plate through nuts, and the mounting end of the thick stud passes through the mounting hole of the adapter plate and is connected to the second end of the sliding platform through a thick nut; by adjusting the power of the first heating coil or the power of the second heating coil separately, differential heating of the inner and outer material properties of the metal composite pipe can be achieved; The induction welding method specifically comprises the following steps: S1. According to the requirements of the pipeline to be produced, the number n of the second coil group is determined, and the positions of the thick studs and studs in the second coil group are adjusted so that the second heating coil in the second coil group reaches the corresponding position, and the first coil group is fixed above the pipeline welding position; S2, determining the material properties of the plate required in the pipeline to be produced, and setting the heating power P1 of the first heating coil and the heating power P2 of the second heating coil through a high-frequency power supply; S3, according to the first thermal diffusion time t1 required for the inner plate after the plurality of second coil groups are heated and the second thermal diffusion time t2 required for the outer plate after the first second coil group is heated, respectively adjust the first spacing L1 between the first coil group and the first second coil group and the second spacing L2 between the plurality of second coil groups, so as to obtain the initial spacing of the device, wherein the expression of the first thermal diffusion time t1 is: t1=K / (nP2) Where K is the proportionality coefficient; The expression of the second thermal diffusion time t2 is: t2=K / P2 Where K is the proportionality coefficient; S4, based on step S3, respectively adjusting the first distance L1 between the first coil group and the second coil group and the second distance L2 between adjacent second coil groups, so that the temperature required for the pipe to be produced during the heating and welding process is more uniform; S5, respectively set the temperature interval C2 of the inner plate and the temperature interval C1 of the outer plate, and start production by the feeding mechanism, so that the pipe to be produced is sent to the second coil group and the first coil group for heating through the feeding mechanism at the plate and strip forward speed V; if the plate and strip forward speed V changes, proceed to step S3, if the plate and strip forward speed V does not change, proceed to step S6; S6. Compare the temperature values ​​of the inner plate and the outer plate collected by the infrared camera with the temperature interval C2 of the inner plate and the temperature interval C1 of the outer plate respectively. If the temperature value of the outer plate is higher than the temperature interval C1 of the outer plate, reduce the heating power P1 of the first heating coil and return to step S2. If the temperature value of the outer plate is lower than the temperature interval C1 of the outer plate, increase the heating power P1 of the first heating coil and return to step S2. If the temperature value of the inner plate is higher than the temperature interval C2 of the inner plate, reduce the heating power P2 of the second heating coil and return to step S2. If the temperature value of the inner plate is lower than the temperature interval C2 of the inner plate, increase the heating power P2 of the second heating coil and return to step S2. If the temperature value of the outer plate is within the temperature interval C1 of the outer plate and the temperature value of the inner plate is within the temperature interval C2 of the inner plate, complete the temperature adjustment of the inner and outer plates before welding.

2. The induction welding method for metal composite pipe according to claim 1, characterized in that: The mounting ends of the first coil group, the second coil group, the extrusion roller, the high-frequency power supply, the feeding mechanism and the circulating water pump are respectively connected to the first mounting end, the second mounting end, the third mounting end, the fourth mounting end, the fifth mounting end and the sixth mounting end of the substrate.

3. The induction welding method for metal composite pipe according to claim 1, characterized in that: The first coil group is located outside the pipeline, and the second coil group is located inside the pipeline.

4. The induction welding method for metal composite pipe according to claim 1 or 3, characterized in that: The number of the first coil group is one, and the number of the second coil group is at least one.

5. The induction welding method for metal composite pipe according to claim 1, characterized in that: The magnetic conductor and the second heating coil are respectively located on both sides of the pipeline wall. The magnetic conductor is located on the outer surface of the pipeline wall, and the second heating coil is located on the inner surface of the pipeline wall.

6. The induction welding method according to claim 1, characterized in that: In step S2, the material properties of the required plate include the thickness H1 of the inner plate, the thermal conductivity λ1 of the inner plate, the thickness H2 of the outer plate, and the thermal conductivity λ2 of the outer plate.

7. The induction welding method according to claim 6, characterized in that: The magnitudes of the heating power P1 of the first heating coil and the heating power P2 of the second heating coil are respectively related to the thickness H1 of the inner plate, the thermal conductivity λ1 of the inner plate, the thickness H2 of the outer plate and the thermal conductivity λ2 of the outer plate.

8. The induction welding method according to claim 1, characterized in that: In step S3, the proportionality coefficient K is proportional to the thickness H of the plate and inversely proportional to the thermal conductivity λ.

9. The induction welding method according to claim 1, characterized in that: In step S3, the first distance L1 is expressed as: L1=V×t1 Wherein, V is the production speed of the plate; The expression of the second distance L2 is: L2=V×t2 Wherein, V is the production speed of the plate.

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