Copper-iron composite material coiled welded pipe, welding process and welding device

Abstract

The present application discloses a copper-iron composite material coiled welded pipe, a welding process and a welding device, wherein the welding process steps include: S1: the copper-iron composite material embryonic tube rolled into a tube enters a resistance heating furnace for heating, and the heating temperature is 0°C-1000°C; S2: the copper-iron composite material embryonic tube after S1 enters an induction heating device for N-stage step-by-step induction heating and heating, and the heating temperature of the induction heating is higher than the heating temperature of the resistance heating furnace in step S1; the composite coil reaches the melting point of copper after the N-stage induction heating, so as to weld the copper-iron composite material embryonic tube, wherein N is an integer greater than 1; S3: the copper-iron composite material pipe after the N-stage induction heating welding is completed is cooled; the composite heating welding method is used to improve the problems of uneven heating during welding and poor consistency of the thickened copper layer after welding of the copper-iron composite material coiled welded pipe.

Description

Technical Field

[0001] The present application relates to the field of welding technology for coiled welded pipes, and in particular to a copper-iron composite material coiled welded pipe, a welding technology, and a welding device. Background Art

[0002] Generally, coiled welded pipes are formed from cold-rolled steel strips coated with brazing filler metal (copper or other metal solder) through a forming unit into double-layer coiled pipe blanks. The filler metal between the layers is then heated at high temperatures to melt and bake the pipes together. Since single-layer welded steel pipes generally have a longitudinal weld seam, while double-layer coiled welded pipes have full-circumference welds, the strength and sealing properties of the welds in double-layer coiled welded pipes are the same as those of seamless pipes.

[0003] In the prior art, double-layer coiled welded pipes are heated in a resistance heating furnace to heat the pipe to or above the melting point of the brazing material, causing it to melt and penetrate into various parts of the pipe wall. After cooling, the two layers of iron-based materials are combined into a solid whole.

[0004] However, during the processing of copper-clad steel strip pipes, due to the increase in copper thickness (copper layer thickness ≥ 5 microns), the thermal efficiency of the resistance heating furnace in heating the pipe is low, which will also lead to uneven heating of the pipe. When the pipe is heated to the copper melting point, the copper layer on the surface of the pipe has a large error, thereby reducing the welding quality of the pipe. Summary of the Invention

[0005] In order to improve the problems of uneven heating during welding and poor consistency of the thickened copper layer after welding of copper-iron composite material welded pipes, the present application provides a copper-iron composite material welded pipe, a welding process and a welding device.

[0006] The first invention of this application is to provide a welding process for a copper-iron composite material coil welded pipe, which adopts the following technical solution:

[0007] A welding process for a copper-iron composite material coil welded pipe is used for welding a copper-iron composite material embryonic pipe. The welding process steps include:

[0008] S1: The copper-iron composite material embryo tube rolled into a tubular shape enters a resistance heating furnace for heating at a temperature of 0°C-1000°C;

[0009] S2: After S1, the copper-iron composite material embryo tube enters an induction heating device for N-stage step-by-step induction heating. The induction heating temperature is higher than the heating temperature of the resistance heating furnace in step S1. After the N-stage induction heating, the copper-iron composite material embryo tube reaches the melting point of copper, so that the copper-iron composite material embryo tube is welded to obtain the copper-iron composite material coil welded tube, wherein N is an integer greater than 1.

[0010] S3: Cooling the copper-iron composite material welded pipe obtained after completing the N-stage induction heating welding.

[0011] By adopting the above technical solution, the copper-iron composite coiled welded pipe is obtained by the copper cladding process; other processes can be copper plating processes; this application is different from the traditional single heating method. The disadvantage of single heating is that it is difficult to ensure the stability of welding, the relative consistency of the surface copper layer, and it is difficult to improve the structural strength while avoiding the thermal deformation and uneven melting of the material. The present application uses a resistance heating furnace for initial heating, the heating temperature is controlled within 1000 degrees Celsius, and then it is heated by induction heating one or more times to reach the melting point of copper, aiming to reduce the heat affected zone, improve the stability of welding, the relative consistency of the surface copper layer, the welding strength and uniformity, while ensuring production efficiency; finally, it is cooled, the coiled welded pipe is solidified and formed, and the pipe is passivated and anti-oxidation treated after cooling. This application achieves uniform heating and high-quality welding of composite material coiled welded pipes. Induction heating can quickly and evenly increase the pipe temperature, avoiding the problem of uneven heating for thickened copper layer pipes in traditional resistance heating methods. At the same time, by gradually increasing the heating temperature and one or more induction heatings, the firmness of the weld and the overall sealing of the pipe are ensured.

[0012] Optionally, the copper-iron composite material embryonic tube is a copper-iron-based material-copper composite material embryonic tube.

[0013] By adopting the above technical solution, the iron-based material in the copper-iron-copper composite embryonic tube is selected from an ultra-low carbon iron-based material, specifically an ultra-low carbon steel plate with a carbon content of less than 0.03%. Due to its extremely low carbon content, this material has excellent plasticity and toughness. The ultra-low carbon iron-based material becomes softer and thermoplastic through copper cladding, approaching the softness of copper, making the entire copper-iron composite coiled welded tube similar in softness to copper tubes. The mechanical properties of the copper strip and the selected ultra-low carbon steel plate are consistent, and under high-temperature heating conditions, the residual stress of the ultra-low carbon iron-based material is released. Due to the increased thermal motion of atoms during the heat treatment, the material's electrical and thermal conductivity also changes.

[0014] Optionally, the thickness of the copper layer on one side of the copper-iron composite material embryo tube before forming and welding is ≥5 microns.

[0015] By adopting the above technical solution, a copper layer thickness greater than 5 microns is considered thicker. The existing technology can only weld copper strips with a thickness of less than 5 microns, while the welding process in this application can be used to produce coiled welded pipes with a copper strip thickness of more than 5 microns.

[0016] Optionally, the oscillation frequency of the induction heating device is 5-100 KHz.

[0017] By adopting the above technical solution, the current generated by the oscillation frequency of 5-100kHz can more effectively penetrate the metal surface, uniformly heating the interface in a short time, thereby improving the welding quality. The current generates rapid and uniform heat in the coil-welded pipe. This helps to quickly reach the required process temperature and improve production efficiency.

[0018] The second invention of this application is to provide a copper-iron composite material coil welded pipe, which adopts the following technical solution:

[0019] A copper-iron composite material welded pipe is produced by the above-mentioned welding process.

[0020] Optionally, the outer diameter of the copper-iron composite material welded pipe after welding is 4 mm to 32 mm.

[0021] The third invention of this application is to provide a copper-iron composite material coil welded pipe welding and heating device, which adopts the following technical solutions:

[0022] A copper-iron composite material coil welded pipe welding device includes a resistance heating furnace and an induction heating device. The resistance heating furnace can heat the entire circumference of the pipe. The induction heating device includes a support plate and an electromagnetic induction coil. The electromagnetic induction coil is connected to the surface of the support plate. The electromagnetic induction coil is passed through the pipe of the resistance heating furnace. The electromagnetic induction coil can heat the entire circumference of the pipe.

[0023] By adopting the above technical solution, the pipe passes through the resistance heating furnace and the electromagnetic induction coil in sequence. The resistance heating furnace heats the entire circumference of the pipe to achieve preliminary heating of the pipe. The pipe that has completed the preliminary heating is passed through the electromagnetic induction coil, and the electromagnetic induction coil further heats the entire circumference of the pipe to achieve segmented and step-by-step heating transition of the pipe, so that the entire circumference of the pipe is heated evenly, which promotes the melting and welding of the pipe into one piece, thereby improving the welding quality of the pipe.

[0024] Optionally, the induction heating device further includes an insulation component, the insulation component includes an insulation tube, the end of the insulation tube is connected to the discharge end of the resistance heating furnace, the inner cavity of the insulation tube is for the pipe to pass through, and the electromagnetic induction coil surrounds the outer circumference of the insulation tube.

[0025] By adopting the above technical solution, when the pipe enters the inner cavity of the insulation tube from the discharge end of the resistance heating furnace, the electromagnetic induction coil surrounds the outer circumference of the insulation tube, and the electromagnetic induction coil heats the pipe inside the insulation tube, so that heat energy is accumulated in the inner cavity of the insulation tube, ensuring that the pipe is heated evenly around the entire circumference, making the pipe less susceptible to external factors, thereby improving the welding quality of the composite material welded pipe.

[0026] In summary, this application includes at least one of the following beneficial technical effects:

[0027] 1. The resistance heating plus induction heating combined welding process realizes the segmented and step-by-step heating transition of the pipe, so that the pipe is heated evenly all around, promoting the melting and welding of the pipe into one piece, thereby improving the welding quality of the pipe and realizing the gradual heating transition of the pipe, thereby achieving the stability of the melting and welding of the pipe into one piece;

[0028] 2. The composite material welded pipe made by the welding process of the present application is used in automobile fuel lines, brake lines, and air-conditioning lines to improve the performance and safety of the automobile; it can also be used in the home appliance industry to manufacture condenser tubes and evaporator tubes of refrigeration equipment such as refrigerators and air conditioners to improve refrigeration efficiency and energy-saving performance; it has also been widely used in the engineering machinery industry and can be used to manufacture oil pipes and air pipes in hydraulic systems to improve the working efficiency and reliability of the machinery. In addition, the composite material welded pipe in the present application has good machinability and corrosion resistance, and can be bent, cut, welded and other processing operations as needed to meet the needs of different application scenarios. It has been widely used in various fluid piping systems, especially replacing users who currently use pure copper pipe products, which will greatly save costs while ensuring product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure in Example 1 of the present application.

[0030] Figure 2 It is a schematic diagram of the local structure in Example 1 of the present application, mainly showing the electromagnetic induction coil.

[0031] Figure 3 It is a partial cross-sectional view in Example 1 of the present application, mainly showing the thermal insulation component.

[0032] Explanation of the accompanying drawings: 1. Base; 2. Resistance heating furnace; 3. Induction heating device; 31. Support plate; 32. Electromagnetic induction coil; 33. Thermal insulation assembly; 331. Thermal insulation tube; 332. Thermal insulation cover; 333. Positioning roller one; 3331. Positioning space; 3332. Positioning ring groove one; 334. Positioning roller two; 3341. Positioning ring groove two; 335. Power motor; 34. Circuit connecting device; 4. Pipe; 5. Visual mirror; 6. Temperature detector; 7. Cooling tube. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1-3 This application is described in further detail.

[0034] Example 1: A copper-iron composite material coiled pipe welding and heating device. Figure 1, including a base 1, a resistance heating furnace 2 and an induction heating device 3. The bottom of the base 1 abuts the ground to form a support. The resistance heating furnace 2 is installed on the top surface of the base 1 by bolts. The heating temperature range of the resistance heating furnace 2 is 0℃ to 1000℃. The resistance heating furnace 2 can preheat the pipe 4.

[0035] Reference Figure 1 The induction heating device 3 is installed on the top surface of the base 1. The induction heating device 3 can heat the preheated pipe 4 step by step. The heating temperature range of the induction heating device 3 is 200°C to 1200°C. In the embodiment of the present application, the heating temperature of the induction heating device 3 is 1100°C, which can reach the melting point of copper, so that the pipe 4 can be welded into one piece, thereby obtaining a composite material welded pipe with an outer diameter of 4mm-32mm.

[0036] Reference Figure 1 and Figure 2 The induction heating device 3 includes a bracket plate 31, an electromagnetic induction coil 32, a thermal insulation component 33 and a circuit connection device 34. In the embodiment of the present application, the number of electromagnetic induction coils 32 and bracket plates 31 is multiple, and multiple bracket plates 31 are fixed at intervals on the top surface of the base 1. The arrangement direction of the bracket plates 31 is parallel to the axis of the pipe 4. The electromagnetic induction coils 32 correspond to the bracket plates 31 one by one. The electromagnetic induction coils 32 are installed on the plate surface of the bracket plate 31, and the axis of the electromagnetic induction coils 32 coincides with the axis of the pipe 4. The pipe 4 preheated by the resistance heating furnace 2 can be sequentially passed through one or more electromagnetic induction coils 32. The electromagnetic induction coils 32 can heat the entire circumference of the pipe 4 to achieve the melting and welding of the pipe 4 into one.

[0037] Reference Figure 1 and Figure 2 In the embodiment of the present application, there are multiple insulation components 33, and multiple insulation components 33 are connected at intervals on the top surface of the base 1. The arrangement direction of the insulation components 33 is parallel to the axis of the pipe 4, and the insulation components 33 can guide the pipe 4 for insulation. When the number of bracket plates 31 between adjacent insulation components 33 is more, that is, the number of electromagnetic induction coils 32 is more, the total length of the electromagnetic induction coil 32 is longer, and the temperature reached by the electromagnetic induction coil 32 is higher. When the number of bracket plates 31 between adjacent insulation components 33 is fewer, that is, the number of electromagnetic induction coils 32 is fewer, the total length of the electromagnetic induction coil 32 is shorter, and the temperature reached by the electromagnetic induction coil 32 is lower, so that the pipe 4 can pass through the low-temperature heating zone, the high-temperature heating zone and then the low-temperature heating zone in sequence, to achieve a step-by-step heating transition of the pipe 4, so that the pipe 4 can be subsequently melted and welded into one.

[0038] Reference Figure 1 and Figure 2In the embodiment of the present application, there are multiple circuit connecting devices 34, and the circuit connecting devices 34 correspond to the insulation components 33 one by one. The circuit connecting devices 34 are electrically connected to the multiple electromagnetic induction coils 32 between adjacent insulation components 33. In the embodiment of the present application, the circuit connecting device 34 is a relay, and the circuit connecting device 34 can control the on and off of the multiple electromagnetic induction coils 32; the staff can adjust the total length of the electromagnetic induction coils 32 between adjacent insulation components 33 according to the required temperature of the pipe 4, so that the pipe 4 can be stably melted and welded into one, thereby improving the versatility of the composite material rolled pipe welding and heating device for welding pipes 4 of different diameters.

[0039] Reference Figure 2 and Figure 3 The insulation assembly 33 includes an insulation tube 331, an insulation cover 332, a positioning roller 1 333, a positioning roller 2 334 and a power motor 335. The insulation cover 332 is fixed to the top surface of the base 1 by bolts. The material of the insulation tube 331 can be polycarbonate or polyamide. In the embodiment of the present application, the material of the insulation tube 331 is polycarbonate, which is transparent, heat-insulating and high-temperature resistant.

[0040] Reference Figure 1 and Figure 3 The two ends of the insulation tube 331 in the axial direction are fixed one by one on the surfaces of adjacent insulation covers 332 facing each other. The other end of the insulation tube 331 on the insulation cover 332 facing the resistance heating furnace 2 is fixed to the discharge end of the resistance heating furnace 2. The axis of the insulation tube 331 coincides with the axis of the pipe 4. The pipe 4 discharged from the discharge end of the resistance heating furnace 2 can pass through the insulation tube 331 and the insulation cover 332 in sequence. The electromagnetic induction coil 32 surrounds the outer circumference of the insulation tube 331, and the axis of the electromagnetic induction coil 32 coincides with the axis of the insulation tube 331. The electromagnetic induction coil 32 can heat the pipe 4 in the inner cavity of the insulation tube 331.

[0041] Reference Figure 3 The positioning roller 1 333 and the positioning roller 2 334 are connected to the inner wall of the heat insulation cover 332 in an alternating manner. The axis of the positioning roller 1 333 and the axis of the positioning roller 2 334 are parallel to each other, and the axis of the positioning roller 1 333 and the axis of the pipe 4 are perpendicular to each other. A positioning space 3331 for the pipe 4 to pass through is reserved between the positioning roller 1 333 and the positioning roller 2 334, so that the pipe 4 is not prone to shaking during the heating process, thereby improving the stability of heating the pipe 4; at the same time, the roller surface of the positioning roller 1 333 and the roller surface of the positioning roller 2 334 are in rolling contact with the outer periphery of the pipe 4, and rolling friction replaces sliding friction, reducing the wear between the positioning roller 1 333, the positioning roller 2 334 and the pipe 4, thereby improving the production quality of the pipe 4.

[0042] Reference Figure 3The first positioning roller 333 is coaxially provided with a first positioning ring groove 3332 for the pipe 4 to pass through, and the second positioning roller 334 is coaxially provided with a second positioning ring groove 3341 for the pipe 4 to pass through. The positioning space 3331 is located between the first positioning ring groove 3332 and the second positioning ring groove 3341. When the pipe 4 passes through the positioning space 3331, the inner wall of the first positioning ring groove 3332 and the inner wall of the second positioning ring groove 3341 abut against the outer periphery of the pipe 4 to form a limit, so that the pipe 4 is not easy to escape from the positioning space 3331, thereby improving the stability of the pipe 4 passing through the positioning space 3331.

[0043] Reference Figure 3 The power motor 335 is fixed to the side wall of the heat insulation cover 332 by bolts, and the motor axis of the power motor 335 coincides with the axis of the positioning roller 1 333. The end of the motor shaft of the power motor 335 passes through the side wall of the heat insulation cover 332 and is coaxially fixed on the rotating shaft of the positioning roller 1 333. When the power motor 335 is running, it drives the positioning roller 1 333 to rotate around its own axis, and the roller surface of the positioning roller 1 333 rolls in contact with the outer periphery of the pipe 4. The outer periphery of the pipe 4 rolls in contact with the roller surface of the positioning roller 2 334, driving the positioning roller 2 334 to rotate around its own axis, driving the pipe 4 to pass through the positioning space 3331.

[0044] Reference Figure 3 A visual mirror 5 is installed on the surface of the heat insulation cover 332. In the embodiment of the present application, the material of the visual mirror 5 is glass, which has good light transmittance. The visual mirror 5 can observe the inner cavity of the heat insulation cover 332. The staff can observe the embedding status of the pipe 4 and the positioning space 3331 through the visual mirror 5, so that the staff can adjust the position of the pipe 4 in the positioning space 3331 in time, thereby improving the welding efficiency of the copper-iron composite material rolled welded pipe.

[0045] Reference Figure 3 A temperature detector 6 is installed on the top of the heat insulation cover 332. The temperature detector 6 can detect the temperature of the inner cavity of the heat insulation cover 332, so that the staff can monitor the temperature of the pipe 4 in real time, thereby improving the welding accuracy of the copper-iron composite material welded pipe.

[0046] Reference Figure 1 A cooling pipe 7 is fixed on the surface of the heat insulation cover 332 away from the heat insulation tube 331. The axis of the cooling pipe 7 coincides with the axis of the pipe 4. The pipe 4 in the heat insulation cover 332 can be embedded in the inner cavity of the cooling pipe 7. The cooling pipe 7 can cool the pipe 4, reduce the stress inside the pipe 4, and reduce the deformation or cracking of the pipe 4, thereby improving the production quality of the copper-iron composite material welded pipe.

[0047] The implementation principle of the welding and heating device for a copper-iron composite material rolled welded pipe according to the embodiment of the present application is as follows: the pipe 4 is first preheated by the resistance heating furnace 2, and the preheated pipe 4 passes through multiple insulation pipes 331 and insulation covers 332 in turn. The staff adjusts the total length of the electromagnetic induction coils 32 between adjacent insulation components 33 through the control circuit connection device 34 according to the required temperature of the pipe 4, so as to change the heating temperature of the electromagnetic induction coils 32 between adjacent insulation components 33, so that the pipe 4 can pass through the low-temperature heating zone, the high-temperature heating zone and the low-temperature heating zone in turn, thereby realizing a segmented and step-by-step heating transition of the pipe 4, so that the pipe 4 is heated evenly around the entire circumference, promoting the melting and welding of the pipe 4 into one, thereby improving the welding quality of the pipe 4; at the same time, the pipe 4 passes through the positioning space 3331, the inner wall of the positioning ring groove 1 3332 and the inner wall of the positioning ring groove 2 3341 abut against the outer periphery of the pipe 4 to form a limit, so that the pipe 4 is not prone to shaking during the heating process, thereby ensuring the stability of the heating of the pipe 4.

[0048] Example 2: A welding process for a copper-iron composite material coil-welded pipe, using the above-mentioned Example 1 to complete the welding process of the copper-iron-based material-copper composite coil-welded pipe. The process steps of this embodiment include:

[0049] S1: The coiled copper-iron-based material-copper composite coil enters a resistance heating furnace for heating and welding. The heating temperature is 0°C-1000°C. The specific heating temperature can be selected according to the different types and specifications of products. The composite pipe is a composite pipe formed by metallurgical composite copper strips. From the outside to the inside, it is copper strip, ultra-low carbon steel plate, and copper strip. The thickness of a single copper strip is ≥5 microns. The welding process of this application can be used to produce composite coil welded pipes with a single-sided copper strip thickness of 5 microns or more.

[0050] S2: The pipe after S1 enters the induction heating device for induction heating welding, and the heating temperature is higher than the heating temperature in step S1, specifically within 1200°C; the copper-iron-based material-copper composite coil reaches the melting point of copper after one or more stages of induction heating in step S2, and the melting point of copper is 1083°C; when the induction heating stage is one stage, the induction heating temperature is set within 1200°C, and the coil is directly melted and formed in this stage;

[0051] The induction heating section is one or more than two sections, and the induction heating temperature is finally set to within 1200°C. The copper-iron-based material-copper composite coil can be heated and melted step by step through the first section and the second section, and then welded into shape.

[0052] S3: The composite pipe is cooled after welding. In this application, air cooling or water cooling is used to cool the pipe to ambient temperature.

[0053] S4: After cooling, a composite material welded pipe is obtained, and the outer diameter of the composite material welded pipe ranges from 4 mm to 32 mm.

[0054] In this embodiment, the oscillation frequency of the induction heating device is 5-100KHz. 5-100KHz is selected in this application. The appropriate temperature can be selected according to the different types and specifications of products to make the heating temperature faster and the welding efficiency higher.

[0055] In this embodiment, the iron-based material in the copper-iron-copper composite material is ultra-low carbon steel plate. Due to its extremely low carbon content, this material exhibits excellent plasticity and toughness. After welding at temperatures of approximately 1000°C or above, the residual stress in the ultra-low carbon iron-based material is released. Due to the increased thermal motion of atoms during the heat treatment, the material's electrical and thermal conductivity also changes. The ultra-low carbon iron-based material becomes more flexible and thermoplastic, approaching the softness of copper pipes.

[0056] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A welding device for a copper-iron composite material coil welded pipe, characterized in that: The welding device includes a resistance heating furnace and an induction heating device. The resistance heating furnace can heat the entire circumference of the pipe. The induction heating device includes a bracket plate and an electromagnetic induction coil. The electromagnetic induction coil is connected to the surface of the bracket plate. The electromagnetic induction coil is passed through the pipe of the resistance heating furnace. The electromagnetic induction coil can heat the entire circumference of the pipe. The number of the electromagnetic induction coils and bracket plates is multiple. The induction heating device also includes multiple thermal insulation components and multiple circuit connecting devices. The thermal insulation component can insulate and guide the pipe. The circuit connecting device corresponds to the thermal insulation component one by one. The circuit connecting device is electrically connected to the multiple electromagnetic induction coils between adjacent thermal insulation components. The circuit connecting device can control the on and off of the multiple electromagnetic induction coils. The thermal insulation component includes a thermal insulation cover. The pipe passing through the electromagnetic induction coil can pass through the thermal insulation cover. The thermal insulation component also includes a thermal insulation pipe The end of the heat insulation pipe is connected to the discharge end of the resistance heating furnace, the inner cavity of the heat insulation pipe is for the pipe to pass through, and the electromagnetic induction coil surrounds the outer circumference of the heat insulation pipe; the heat insulation assembly also includes a positioning roller one and a positioning roller two, the positioning roller one and the positioning roller two are connected to the inner wall of the heat insulation cover in an interval and rotational manner, the axis of the positioning roller one and the axis of the positioning roller two are parallel to each other, and the axis of the positioning roller one and the axis of the pipe are perpendicular to each other, and a positioning space for the pipe to pass through is reserved between the positioning roller one and the positioning roller two, the positioning roller is coaxially provided with a positioning ring groove one for the pipe to pass through, and the positioning roller two is coaxially provided with a positioning ring groove two for the pipe to pass through, the positioning space is located between the positioning ring groove one and the positioning ring groove two, a temperature detector is installed on the top of the heat insulation cover, a cooling pipe is fixed on the surface of the heat insulation cover away from the heat insulation pipe, the axis of the cooling pipe coincides with the axis of the pipe, and the pipe in the heat insulation cover can be embedded in the inner cavity of the cooling pipe.

2. A welding process for a copper-iron composite material coiled welded pipe, using the copper-iron composite material coiled welded pipe welding device according to claim 1, the welding process comprising: S1: The copper-iron composite material embryo tube rolled into a tubular shape enters a resistance heating furnace for heating at a temperature of 0°C-1000°C; S2: After S1, the copper-iron composite material embryo tube enters an induction heating device for N-stage step-by-step induction heating. The induction heating temperature is higher than the heating temperature of the resistance heating furnace in step S1. After the N-stage induction heating, the copper-iron composite material embryo tube reaches the melting point of copper, so that the copper-iron composite material embryo tube is welded to obtain the copper-iron composite material coil welded tube, wherein N is an integer greater than 1. S3: Cooling the copper-iron composite material welded pipe obtained after completing the N-stage induction heating welding.

3. The welding process for a copper-iron composite material coil welded pipe according to claim 2, characterized in that: The copper-iron composite material embryo tube is a copper-iron-based material-copper composite material embryo tube.

4. The welding process for a copper-iron composite material coil welded pipe according to claim 2, characterized in that: The thickness of the single-side copper layer of the copper-iron composite material embryo tube before forming and welding is ≥5 microns.

5. The welding process for a copper-iron composite material coil welded pipe according to claim 2, characterized in that: The oscillation frequency of the induction heating device is 5-100 KHz.

6. A copper-iron composite material coiled welded pipe, characterized in that: The copper-iron composite material welded pipe is produced by the welding process described in any one of claims 2 to 5.

7. The copper-iron composite material welded pipe according to claim 6, characterized in that: The outer diameter of the copper-iron composite material welded pipe after welding is 4mm-32mm.

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