High-frequency electric welding process for gas copper pipe joint

Abstract

The invention relates to the technical field of electromagnetic welding, in particular to a high-frequency electric welding process for a gas copper pipe joint. The high-frequency electric welding process for the gas copper pipe connector further comprises the following operation steps that S1, foreign matter cleaning is conducted, wherein it is ensured that the end faces of the two copper pipes and a connector workpiece are smooth and free of oil contamination oxidation; s2, welding rings are pre-placed, specifically, the prefabricated welding rings are arranged in ports of the two copper pipes in a sleeving mode correspondingly; s3, pipe fitting assembling, wherein the two copper pipes are in coaxial butt joint with the two ends of the connector workpiece correspondingly and pressed tightly; the size specification of the prefabricated welding ring is obtained according to the outer diameter of the copper pipe, the gap between the copper pipe and the connector workpiece, the insertion length of the copper pipe and the inner wall of the connector workpiece and the outer fillet process requirement. S4, induction welding is conducted, specifically, an electromagnetic induction welding machine is started, heating continues to be kept for 2-3 seconds after a welding ring is evenly melted through heat conduction, and it is guaranteed that gaps are filled; and S5, cooling and shaping are conducted, specifically, the electric welding process is completed, and subsequent to-be-welded parts are naturally cooled. S6, appearance and interior detection, wherein defects such as weld lack and weld beading of weld joints are visually inspected; and a welding part is detected by adopting a ray and air pressure test.

Description

A high-frequency electric welding process for gas copper pipe joints Technical Field

[0001] This invention belongs to the field of electromagnetic welding technology, specifically relating to a high-frequency electric welding process for gas copper pipe joints. Background Technology

[0002] In gas pipeline systems, the reliability of the connections between copper pipes directly affects the sealing safety and long-term stable operation of the entire pipeline system. Brazing is one of the core technologies, which involves melting a filler metal (such as silver-based filler metal) with a melting point lower than that of the base metal, and filling the joint gap under capillary action to achieve a metallurgical bond.

[0003] Traditional copper pipe brazing primarily uses flame heating. This technique relies on the operator's experience to manually adjust the flame size and position for localized heating of the copper pipe joint area. Although the equipment is simple and inexpensive, the large temperature gradient in the heating area can easily cause localized overheating or uneven heating of the base material; it is highly dependent on operator skill, making it difficult to guarantee consistent quality; and open flame operations pose safety hazards, making it unsuitable for certain specific situations.

[0004] In response, electromagnetic induction brazing technology has emerged in the market. This technology utilizes the alternating magnetic field generated by a high-frequency induction coil to induce eddy currents in the copper tube, thereby generating heat. This achieves heating efficiency, controllable heat-affected zone, easy automation integration, and non-contact, rapid, and relatively uniform heating.

[0005] However, both traditional flame brazing and improved electromagnetic induction brazing face a common and critical problem in ensuring weld quality: precise control of the filler metal (usually pre-loaded as a ring wire). In existing technologies, the selection of the filler wire diameter largely relies on experience or general standards (e.g., fixed specifications like 1.5mm or 1.6mm), lacking precise calculation and matching for specific joint geometry parameters (such as copper tube outer diameter, assembly gap, and insertion depth) and specific weld formation process requirements (such as the need for full inner and outer fillet radii). This crude selection leads to two main defects: insufficient filler metal filling (missing welds): when the filler wire diameter (i.e., volume) is too small, the total amount of molten filler metal provided is insufficient to completely fill the annular gap between the copper tube and the joint workpiece. This results in defects such as porosity and incomplete penetration within the weld, and incomplete or even interrupted fillet radii on the outer weld. The result is a severe weakening of the joint's fatigue strength, pressure resistance, and sealing reliability.

[0006] Excessive solder overflow (weld bead): When the diameter (i.e. volume) of the welding wire is too large, there is still excess molten solder after the capillary action fills the gap. This excess solder will flow into the non-welding area, which may block the inner diameter of the pipe and affect the flow of the medium; or form excessively large and irregular weld beads on the outside of the weld. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a high-frequency electric welding process for gas copper pipe joints.

[0008] The objective of this invention can be achieved through the following technical solution: a high-frequency electric welding process for gas copper pipe joints, comprising an electromagnetic induction welding machine for high-frequency welding of gas copper pipes, consisting of a high-frequency power supply, a control system, a high-frequency induction coil, and a cooling system, and further including the following operating steps: S1: Cleaning foreign objects: ensuring that the end faces of the two copper pipes and the joint workpiece are flat, clean, and free of oil and oxidation; S2: Pre-placement of welding rings: pre-made welding rings are respectively fitted onto the ends of the two copper pipes; the ends are reserved for the joint workpiece to be joined; S3: Pipe assembly: the two copper pipes are coaxially joined and pressed together with the two ends of the joint workpiece, ensuring that the pre-made welding rings are evenly embedded in the joining gap; the dimensions of the pre-made welding rings are specified. The parameters are determined by the outer diameter of the copper tube, the gap between the copper tube and the joint workpiece, the insertion length of the inner wall of the copper tube and the joint workpiece, and the outer radius process requirements; S4: Induction welding: Start the electromagnetic induction welding machine, and supply power to the high-frequency induction coil through the high-frequency power supply to generate an alternating magnetic field in the copper tube joint area. The copper tube generates eddy currents and heats up rapidly. Through heat conduction, the weld ring is uniformly melted and then heated for 2-3 seconds to allow the liquid brazing filler metal sufficient flow time to ensure that the gap is filled; S5: Cooling and shaping: After welding is completed, turn off the high-frequency power supply to stop heating, and pull out the high-frequency induction coil to complete the electric welding process. The subsequent parts to be welded can be allowed to cool naturally.

[0009] S6: Visual and internal inspection: After the welded parts have cooled, visually inspect for defects such as incomplete welds, weld beads, and porosity; and use radiographic and pneumatic tests to inspect the welded parts.

[0010] As a further technical solution of the present invention, the pre-fabricated solder ring is an annular brazing wire, and its diameter d is determined by the following formula: Where V_fillet is the fillet volume required for the outer fillet according to the process requirements, V_wire is the fillet volume of the ring welding wire, D_o is the outer diameter of the copper tube, c is the single-sided radial assembly clearance, and L is the length of the copper tube inserted into the joint workpiece.

[0011] As a further technical solution of the present invention, the high-frequency power supply is a solid-state IGBT high-frequency inverter power supply, used to convert industrial frequency AC power into high-frequency AC power with a frequency of 40-200kHz; the high-frequency power supply has automatic frequency tracking and power stabilization functions.

[0012] As a further technical solution of the present invention, the high-frequency induction coil is a spiral U-shaped copper tube structure, the inner diameter profile of which matches the outer diameter of the copper tube to be welded, and the outer surface is covered with a high-temperature resistant insulating coating.

[0013] As a further technical solution of the present invention, the cooling system includes: an air-cooling unit for forced air cooling of the high-frequency power module; and a water-cooling unit for circulating water cooling of the high-frequency induction coil.

[0014] As a further technical solution of the present invention, in step S4, the control system sets an automatic constant temperature control point to prevent the copper tube base material from overheating, and the constant temperature control point is set to 750°C.

[0015] As a further technical solution of the present invention, in step S4, the power supply time of the high-frequency induction coil is preset based on the outer diameter specification of the copper tube; for copper tubes with outer diameters of DN15 and DN22, the total welding time is 22 seconds and 40 seconds, respectively.

[0016] As a further technical solution of the present invention, in step S1, the cleaning of foreign objects includes: mechanically grinding the outer surface of the copper pipe end to be welded and the inner surface of the joint workpiece to remove the oxide layer, and then using acetone or metal cleaning agent for degreasing and cleaning.

[0017] As a further technical solution of the present invention, in step S6, the inspection includes: visually inspecting the appearance of the weld; inspecting the internal quality of the weld using X-ray non-destructive testing; and conducting a gas pressure sealing test on the welded joint.

[0018] As a further technical solution of the present invention, it also includes an electromagnetic induction welding machine for the above-mentioned high-frequency electric welding process of gas copper pipe joints, comprising: a high-frequency power supply module for providing high-frequency electrical energy; a high-frequency induction coil configured as a spiral U-shaped copper tube structure for generating a high-frequency alternating magnetic field concentrated at the welding interface after being energized; a control system connected to the high-frequency power supply module for presetting and monitoring welding parameters; and a cooling system for cooling the high-frequency power supply module and the high-frequency induction coil.

[0019] The beneficial effects of this invention are as follows: By using a calculation formula, based on the outer diameter of the copper tube, the assembly gap, the insertion length, and the requirements of the fillet process, the total volume of the required brazing fillet is accurately calculated, and the optimal diameter of the prefabricated welding ring (ring brazing wire) is determined accordingly (e.g., 1.89mm for a DN22 pipe diameter); this ensures a precise correspondence between the volume of the brazing fillet and the geometric space requirements of the joint, effectively solving the problems of "insufficient brazing fillet (missing weld, porosity)" and "excessive brazing fillet overflow (weld beads, blockage)" caused by the traditional reliance on experience to select welding wire, thereby achieving full and dense fillet fillets of the weld in a single welding process. Attached Figure Description

[0020] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 is a flowchart of the process steps of the present invention; Detailed Implementation

[0022] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the specific embodiments, structures, features, and effects of the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. Embodiment 1:

[0023] As shown in Figure 1, a high-frequency electric welding process for gas copper pipe joints includes an electromagnetic induction welding machine for high-frequency welding of gas copper pipes, consisting of a high-frequency power supply, a control system, a high-frequency induction coil, and a cooling system. The process also includes the following steps: S1: Cleaning foreign objects: Ensure the end faces of the two copper pipes and the joint workpiece are flat, clean, and free of oil and oxidation; S2: Pre-placement of welding rings: Pre-made welding rings are fitted onto the ends of the two copper pipes respectively; the ends of the welding rings leave space for the joint workpiece to be joined; S3: Pipe assembly: The two copper pipes are coaxially joined and pressed together with both ends of the joint workpiece, ensuring that the pre-made welding rings are evenly embedded in the joint gap; the size and specifications of the pre-made welding rings are specified by the copper pipes. The outer diameter, the gap between the copper tube and the joint workpiece, the insertion length of the inner wall of the copper tube and the joint workpiece, and the outer radius process requirements are determined; S4: Induction welding: Start the electromagnetic induction welding machine, and supply power to the high-frequency induction coil through the high-frequency power supply to generate an alternating magnetic field in the copper tube joint area. The copper tube generates eddy currents and heats up rapidly. Through heat conduction, the weld ring is uniformly melted and then heated for 2-3 seconds to allow the liquid brazing filler metal sufficient flow time to ensure that the gap is filled; S5: Cooling and shaping: After welding is completed, turn off the high-frequency power supply to stop heating, and pull out the high-frequency induction coil to complete the electric welding process. The subsequent parts to be welded can be allowed to cool naturally.

[0024] S6: Visual and internal inspection: After the welded parts have cooled, visually inspect for defects such as incomplete welds, weld beads, and porosity; and use radiographic and pneumatic tests to inspect the welded parts.

[0025] The high-frequency power module uses a solid-state IGBT high-frequency inverter to convert mains frequency (50 / 60Hz) AC power into high-frequency AC power with a frequency of 40-200kHz. This power supply features automatic frequency tracking and power stabilization to ensure constant output power. Its operating parameters can be set as follows: input power approximately 5.7kW, input voltage single-phase 220V, oscillation frequency operating in the range of 150-400kHz, and output current adjustable from 1-27A.

[0026] The control system integrates a human-machine interface (HMI) for presetting and monitoring welding parameters, including heating power, heating time, and automatic temperature control point. To prevent the copper tube base material from overheating and melting (copper's melting point is 1050°C), the system sets the automatic temperature control point to 750°C.

[0027] The high-frequency induction coil is a key component of this application. It has a spiral U-shaped copper tube structure, and its inner diameter profile matches the outer diameter of the copper tube to be welded. The outer surface of the coil is covered with a high-temperature resistant insulating coating (such as a ceramic coating). Through its unique U-shaped structure, the coil can tightly wrap around the copper tube joint area, so that the generated high-frequency alternating magnetic field is highly concentrated at the welding interface, achieving precise and efficient heating. The cooling system consists of two parts: an air-cooling unit and a water-cooling unit. The air-cooling unit consists of a heat sink and a high-speed fan, used to provide forced air cooling for the IGBT module and control motherboard in the high-frequency power module. The water-cooling unit cools the high-frequency induction coil by circulating cooling water. The cooling water pressure is required to be no less than 0.07 MPa, and the flow rate is required to be no less than 3.5 L / min, so as to effectively remove the radiant heat generated by the induction coil during operation.

[0028] In addition, in step S1, the outer surface of the copper pipe end to be welded and the inner surface of the joint workpiece are mechanically ground, and the oxide layer is thoroughly removed using sandpaper with a grit of not less than 400# or a stainless steel wire brush. Subsequently, acetone or a special metal cleaner is used for degreasing and cleaning to ensure that the welding area is clean, free of oil and water, and that the metal is exposed.

[0029] In step S2, pre-formed circular solder rings are inserted into the ends of two cleaned copper pipes. During insertion, it is crucial to ensure that the solder ring's position does not interfere with the subsequent mating of the joint components, leaving sufficient insertion space for the joint components.

[0030] In step S3, two copper tubes are inserted into the connector workpiece from both ends, ensuring that all three remain coaxial. An axial clamping force is applied to ensure tight contact between the copper tube end faces and the limiting steps inside the connector workpiece. During this process, the pre-placed brazing filler ring is evenly compressed within the annular gap formed between the outer wall of the copper tube and the inner wall of the connector workpiece. More specifically, the copper tube outer diameter specifications are DN15 and DN22. The dimensions of the pre-made brazing filler ring (such as cross-sectional diameter and inner diameter) need to be comprehensively calculated and determined based on the copper tube outer diameter, the assembly gap design value, the copper tube insertion depth, and the weld fillet forming process requirements to ensure an appropriate amount of brazing filler.

[0031] In S4, the high-frequency induction welding machine is started. The control system drives the high-frequency power module according to preset parameters, supplying power to the high-frequency induction coil. The high-frequency induction coil generates a high-frequency alternating magnetic field in the copper tube joint area, causing eddy currents to be uniformly generated on the surface of the copper tube without dead zones, resulting in rapid heating. The heat is conducted to uniformly melt the brazing filler metal ring in the gap. When the system detects that the temperature has reached the set value (e.g., 750ºC), it enters the heat preservation stage, continuing to heat for 2-3 seconds. This heat preservation time ensures that the molten liquid brazing filler metal has sufficient time to flow under capillary action and fill the entire annular gap, forming a dense weld.

[0032] S4 also includes S41, which sets the power supply time of the high-frequency power module to the high-frequency induction coil based on the outer diameter specification of the copper tube. The total welding time for DN15 and DN22 specifications is 22 seconds and 40 seconds, respectively. That is to say, excluding the 2-3 seconds required to hold the temperature after heating to the limit, the heating process time for DN15 and DN22 specifications is 19-20 seconds and 37-38 seconds, respectively.

[0033] In S5, after the heating step is completed, the control system automatically shuts off the output of the high-frequency power module. The operator or mechanical device then moves the high-frequency induction coil axially away from the welding area. Subsequently, the workpiece cools naturally in the air, and the brazing filler metal solidifies to form a strong metallurgical bond.

[0034] In S6, after the welded area has completely cooled, a visual inspection is first performed. The weld is visually inspected, or a magnifying glass is used, to check for continuity, fullness, and surface defects such as incomplete welds, excessively large weld beads, porosity, or cracks. Next, internal quality and sealing tests are conducted: X-ray non-destructive testing is used to check for incomplete fusion, porosity, or slag inclusions inside the weld. Finally, a pressure sealing test must be performed on the welded joint. A gas at a specified pressure (such as nitrogen or dry air) is introduced and held at that pressure. The pressure gauge reading is checked for stability, or a leak-detecting liquid is applied to the weld to check for air bubbles, confirming that its sealing performance meets the requirements.

[0035] The following is the process data for using the above-mentioned electromagnetic induction welding machine and high-frequency electric welding process to fill the assembly gaps; form full inner and outer rounded corners to ensure optimal strength and airtightness; and compensate for the extremely small oxidation losses during the heating process.

[0036] Due to losses and oxidation during the welding process between copper tubes and welding wires, the diameter of the annular silver-based welding wire directly determines the weld formation quality, joint strength, and sealing performance in the copper tube insertion brazing process. Existing technologies typically rely on experience or general standards to select the welding wire diameter (such as commonly 1.5mm or 1.6mm), lacking precise calculations for specific joint geometry parameters (outer diameter, gap, insertion length) and external fillet requirements. This leads to problems with insufficient or excessive solder: insufficient solder filling occurs when a smaller diameter welding wire cannot provide enough solder, resulting in incomplete filling of the annular gap, forming defects such as porosity and incomplete penetration; incomplete external fillet formation reduces joint fatigue strength and pressure resistance sealing performance; and secondary welding is required, increasing process complexity and cost.

[0037] Excessive solder overflow: Oversized welding wire provides too much solder, causing it to flow into non-welding areas, clogging pipes or affecting fluid performance; it forms excessively large weld beads, requiring subsequent cleaning and increasing manufacturing costs; excessive solder cooling and shrinkage stress is large, which can easily cause microcracks.

[0038] Specifically, to ensure a full weld formation, reliable strength, and excellent airtightness, the dimensions of the prefabricated welding ring (i.e., the ring-shaped brazing wire) need to be precisely calculated. This embodiment uses the welding of a copper pipe with an outer diameter of 22mm (DN22) to the corresponding joint workpiece as an example to explain in detail the calculation process of the welding wire diameter. The key assembly process parameters are as follows: Copper pipe outer diameter (D0): 22mm; Assembly single-sided radial clearance: 0.15mm (referring to the radial distance between the outer wall of the copper pipe and the inner wall of the joint workpiece); Copper pipe insertion length into the joint workpiece (L): 12mm; Process requirements: The weld seam must form a continuous, full rounded corner to ensure the fatigue strength and sealing reliability of the joint.

[0039] The total volume of welding wire required is the sum of the gap-filling volume and the volume required for fillet filling; therefore, it is necessary to calculate the volume of the fillet filling space and the effective fillet volume after the welding wire melts to meet the fillet filling process requirements. The specific calculation steps are as follows: Gap-filling volume formula: Where c is the single-sided radial clearance = 0.15mm, L is the insertion length = 12mm, D is the inner diameter of the outer tube = d + 2c = 22.3mm, and d is the outer diameter of the inner tube = 22mm.

[0040] The interstitial volume was calculated as follows: The formula for calculating the volume of the fillet process is: The fillet radius rf = 1.098 mm; the inner tube outer diameter is 22 m, and the radius R1 = 11 mm; the fillet volume Vfillet is calculated to be approximately 69.203 mm². 3 =69.2 mm 3 In other words, based on rounding: gap volume: Vgap = 125.3 mm 3 Fillet volume: Vfillet = 69.2 mm 3 Summation: Based on this, we know that (center diameter D0 = 22.0 mm, circumference L ≈ 69.115 mm, total required solder volume V_total = 194.5 mm). 3 ).

[0041] The formula for calculating the volume of welding wire is: in, d is the cross-sectional area of ​​the welding wire; d is the diameter of the welding wire; the circumference of the annular welding wire is L = π × D0 = π × 22.0 ≈ 69.115 mm.

[0042] The following table provides data for ring-shaped welding wires with diameters of 1.6-2.0 mm, based on the formula for calculating welding wire volume: As shown in the figure above, when the welding wire diameter is less than 1.8mm, the welding wire volume is insufficient; when the welding wire diameter is equal to 1.9mm, the welding wire volume is slightly surplus; and when the welding wire diameter is greater than 2.0mm, the welding wire volume exceeds the limit. Therefore, it can be determined that the optimal welding wire volume is between 1.8-1.9mm in diameter.

[0043] The following table, based on the welding wire volume calculation formula, provides a data table for welding wire volumes between 1.8-1.9 mm in diameter: Ring Welding Wire Volume Comparison Table (Center Diameter D0 = 22.0 mm, Circumference L ≈ 69.115 mm, Required Total Welding Volume V_total = 194.5 mm²) 3 ) As can be seen from the table, as the welding wire diameter increases, the welding wire volume gradually approaches and exceeds the required volume. When the diameter is 1.89 mm, the welding wire volume is 193.95 mm². 3 , with the required 194.5 mm 3 The difference is only 0.55 mm 3 The satisfaction rate is 99.72%, basically meeting the requirements. When the diameter is 1.90 mm, the welding wire volume is 195.99 mm². 3 Exceeding 1.49 mm 3 The filler content was 100.77%, slightly excessive; therefore, a 1.89 mm diameter welding wire is closest to the requirement. However, considering potential losses or uneven filling during actual welding, a 1.90 mm diameter welding wire could also be used to ensure sufficiency. However, if precise control of the solder amount is required to avoid overflow, 1.89 mm is preferable.

[0044] In conjunction with the standard welding material diameter of 1.6mm for the DN22 specification of this pipe fitting, 1.89mm exceeds the standard by nearly 2.0mm, which is 11.8% more. This ensures that the gap is completely filled, forming full inner and outer rounded corners, guaranteeing optimal strength and airtightness, and compensating for the extremely small oxidation loss during the heating process.

[0045] Therefore, based on the above welding specifications and processes, the required solder volume is calculated to be 194.5 mm. 3 Based on the comparison of several sets of welding wire diameter data calculated using the known formula, the optimal welding wire diameter is found to be 1.89 mm. This size satisfies the premise of accurate filling, takes into account both process tolerance and structural reliability, and can also match the volume of the solder with the volume required for joint welding, while simultaneously satisfying the gap and fillet radius, resulting in defect-free forming. At the same time, it avoids insufficient or excessive solder, improving material utilization. The first-pass yield rate is significantly improved, making it suitable for automated mass production.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A high-frequency electric welding process for gas copper pipe joints, implemented using an electromagnetic induction welding machine, wherein the electromagnetic induction welding machine comprises a high-frequency power supply, a control system, a high-frequency induction coil, and a cooling system; characterized in that, The process Includes the following steps: S1: Clean foreign objects: Ensure the end faces of the two copper pipes to be welded and the joint workpiece are flat, clean, and free of oil and oxidation; S2: Pre-place welding rings: Insert the pre-made welding rings into the ends of the two copper pipes respectively, leaving space for the butt joint of the joint workpiece; S3: Pipe assembly: Coaxially assemble the two copper pipes with both ends of the joint workpiece and press them together, so that the pre-made welding rings are evenly embedded in the butt joint gap formed by the copper pipes and the inner walls of the joint workpiece; wherein, the size and specifications of the pre-made welding rings are based on the outer diameter of the copper pipes, the assembly gap between the copper pipes and the joint workpieces, and the length of the copper pipes inserted into the joint workpieces. S4: Induction Welding: Start the electromagnetic induction welding machine, supply power to the high-frequency induction coil through the high-frequency power supply, generate a high-frequency alternating magnetic field in the copper pipe joint area, cause eddy currents in the copper pipe and rapidly heat up, the heat melts the weld ring through heat conduction, and continue to heat for 2-3 seconds after the weld ring melts; S5: Cooling and Shaping: After welding is completed, stop heating and remove the high-frequency induction coil to allow the welded part to cool naturally; S6: Inspection: Perform appearance and internal quality inspection on the cooled welded part.

2. The high-frequency electric welding process for gas copper pipe joints according to claim 1, characterized in that, The pre-fabricated solder ring is a ring-shaped brazing wire, and its diameter d is determined by the following formula: Where V_fillet is the fillet volume required for the outer fillet according to the process requirements, V_wire is the fillet volume of the ring welding wire, D_o is the outer diameter of the copper tube, c is the single-sided radial assembly clearance, and L is the length of the copper tube inserted into the joint workpiece.

3. The high-frequency electric welding process for gas copper pipe joints according to claim 1, characterized in that, The high-frequency power supply is a solid-state IGBT high-frequency inverter power supply, used to convert industrial frequency AC power into high-frequency AC power with a frequency of 40-200kHz; the high-frequency power supply has automatic frequency tracking and power stabilization functions.

4. The high-frequency electric welding process for gas copper pipe joints according to claim 1, characterized in that, The high-frequency induction coil has a spiral U-shaped copper tube structure, the inner diameter profile of which matches the outer diameter of the copper tube to be welded, and the outer surface is covered with a high-temperature resistant insulating coating.

5. The high-frequency electric welding process for gas copper pipe joints according to claim 1, characterized in that, The cooling system includes: an air-cooling unit for forced air cooling of the high-frequency power module; and a water-cooling unit for circulating water cooling of the high-frequency induction coil.

6. The high-frequency electric welding process for gas copper pipe joints according to claim 1, characterized in that, In step S4, the control system sets an automatic constant temperature control point to prevent the copper tube base material from overheating. The constant temperature control point is set to 750°C.

7. The high-frequency electric welding process for gas copper pipe joints according to claim 1 or 6, characterized in that, In step S4, the power supply time of the high-frequency induction coil is preset based on the outer diameter specification of the copper tube; for copper tubes with outer diameters of DN15 and DN22, the total welding time is 22 seconds and 40 seconds, respectively.

8. The high-frequency electric welding process for gas copper pipe joints according to claim 1, characterized in that, In step S1, the cleaning of foreign objects includes: mechanically grinding the outer surface of the copper pipe end to be welded and the inner surface of the joint workpiece to remove the oxide layer, followed by degreasing and cleaning with acetone or metal cleaning agent.

9. The high-frequency electric welding process for gas copper pipe joints according to claim 1, characterized in that, In step S6, the inspection includes: visually inspecting the appearance of the weld; inspecting the internal quality of the weld using X-ray non-destructive testing; and conducting a gas pressure sealing test on the welded joint.

10. An electromagnetic induction welding machine for implementing the high-frequency electric welding process for gas copper pipe joints as described in any one of claims 1-9, characterized in that, include: High-frequency power supply module, used to provide high-frequency electrical energy; A high-frequency induction coil, configured as a spiral U-shaped copper tube structure, is used to generate a high-frequency alternating magnetic field concentrated at the welding interface after being energized; a control system, connected to the high-frequency power supply module, is used to preset and monitor welding parameters; and a cooling system is used to cool the high-frequency power supply module and the high-frequency induction coil.

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