Thin-wall superconducting magnet helium pipe welding tool and technology

Abstract

The invention discloses a thin-wall superconducting magnet helium pipe welding tool and process, the thin-wall superconducting magnet helium pipe welding tool is suitable for welding a superconducting magnet and a helium pipe, the superconducting magnet comprises a superconducting cable, and the helium pipe comprises a runway section, a reducing transition section and an extension pipe. The thin-wall superconducting magnet helium pipe welding tool comprises a first fixing device, a cooling device and a second fixing device, the first fixing device or the second fixing device is assembled on a superconducting cable, so that a helium pipe can be in two welding states, in the first state, a runway section is located at an armor helium hole of the superconducting cable, and in the second state, the runway section is located at an armor helium hole of the superconducting cable. The variable-diameter transition section and the runway section at the helium hole are located on the same axis and abut against each other. The thin-wall superconducting magnet helium pipe welding tool and the thin-wall superconducting magnet helium pipe welding process are matched with each other, so that temperature control welding of the helium pipe can be realized, the design quality requirement of a helium pipe welding seam is met, and the welding process problem of welding a helium inlet and outlet pipe on a thin-wall superconducting cable armor is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of low-temperature superconducting welding, and in particular to a welding tool and process for a thin-walled superconducting magnet helium tube. Background Art

[0002] Superconducting magnet refers to an electromagnet made of a coil made of a second-class superconductor with a high transition temperature and a high critical magnetic field at low temperature. Its main feature is that there is no electrical loss caused by wire resistance, and there is no magnetic loss caused by the existence of the iron core, and it has strong practical value. It is widely used in industry and scientific research, but it needs to work at liquid helium temperature and the working environment is relatively harsh.

[0003] In the construction of nuclear fusion, low-temperature superconducting magnet coils are important components in low-temperature nuclear fusion devices. Superconducting magnets are composed of superconducting cables, ring cladding and armor (some also have central spiral tubes). To achieve superconductivity, the superconducting cable needs to be immersed in the liquid helium environment of the armor, so in the design and manufacture of superconducting magnets, there will be a design structure for the liquid helium inlet and outlet. The helium tube inlet and outlet structure is formed by opening helium holes in the armor and then welding pipes to lead out, forming a liquid helium inlet and outlet channel. The coil forms a liquid helium loop, making the superconducting coil superconducting.

[0004] However, low-temperature superconducting magnet coils are generally designed with armor wall thickness of 1.8mm to 2.6mm. The welding of helium tubes on such thin-walled magnet armor also needs to meet the welding quality design requirements of the helium tubes. Therefore, there are great process difficulties for the welding process. How to solve this welding process difficulty is a welding process problem that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to solve the problem of welding helium tubes on thin-walled magnet armor while meeting the welding quality design requirements of the helium tubes, and to propose a thin-walled superconducting magnet helium tube welding tool and process.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A thin-walled superconducting magnet helium tube welding tool is suitable for welding a superconducting magnet and a helium tube, wherein the superconducting magnet comprises a superconducting cable, and the helium tube comprises a runway section, a diameter-changing transition section, and an extension tube, and comprises: a first fixing device, wherein the first fixing device is used to fix the position of the runway section;

[0008] A cooling device, the cooling device is used to cool the welding area between the runway section and the superconducting cable;

[0009] A second fixing device, the second fixing device is used to fix the position of the variable diameter transition section and the runway section during welding;

[0010] Installing the first fixing device or the second fixing device on the superconducting cable so that the helium tube can be in two welding states;

[0011] In a first state, the runway section is located at the armor helium hole of the superconducting cable;

[0012] In the second state, the diameter-changing transition section and the racetrack section at the helium hole are located on the same axis and abut against each other.

[0013] As a further solution of the present invention: the first fixing device includes two cover plates, which are fixed to the superconducting cable after being clamped together. The two clamped cover plates have through holes corresponding to the armor helium holes of the superconducting cable for positioning the runway section.

[0014] As a further solution of the present invention: the two cover plates are fixedly mounted with a rear clamping plate, and the rear clamping plate is connected with fastening bolts.

[0015] As a further solution of the present invention: the cooling device includes a cooling pipe extending into the helium hole, the runway section is sleeved on the cooling pipe, the cooling pipe is penetrated by a bracket, and the bracket is installed on the fastening bolt.

[0016] As a further solution of the present invention: the cooling pipeline is provided with dual parallel channels, and the end of each channel is connected to a water pipeline, and a plug is provided at the tail end of the cooling pipeline.

[0017] As a further solution of the present invention: the second fixing device includes two cover plates, which are fixed to the superconducting cable after being clamped together. The two cover plates after being clamped together have through holes corresponding to the armor helium holes of the superconducting cable for positioning the runway section. The two cover plates after being clamped together also have a positioning hole coaxially formed in the armor helium holes of the superconducting cable for positioning the variable-diameter transition section.

[0018] As a further solution of the present invention: the second fixing device is provided with a hole which passes through from top to bottom and serves as a welding operation area, and the welding part between the runway section and the variable diameter transition section is located in the welding operation area.

[0019] As a further solution of the present invention: the superconducting cable is connected to a temperature measurement system, the temperature measurement system includes a thermocouple, and the thermocouple is electrically connected to a temperature controller.

[0020] A thin-walled superconducting magnet helium tube welding process, using a thin-walled superconducting magnet helium tube welding tool, comprising:

[0021] Assemble the superconducting cable, the first fixing device and the cooling device, and thread the runway section into the cooling device and insert it into the helium hole of the superconducting cable armor;

[0022] Four-point spot welding is used to position the runway section, and then the TIG welding process is used to weld the upper and lower sections symmetrically. During welding, the temperature is reduced by a cooling device that has passed the inspection;

[0023] After the runway section and the superconducting cable are welded, the weld is inspected, and after passing the inspection, the superconducting cable welded with the runway section is assembled with the second fixture;

[0024] The variable diameter transition section and the runway section are positioned by a second fixing device, and after positioning, TIG welding process is used for welding.

[0025] As a further solution of the present invention: during the welding process between the runway section and the superconducting cable, it is necessary to monitor the temperature of the superconducting cable through a temperature measurement system.

[0026] Beneficial effects of the present invention:

[0027] (1) In the present invention, by using a thin-walled superconducting magnet helium tube welding tool and a thin-walled superconducting magnet helium tube welding process in cooperation with each other, the temperature-controlled welding of the helium tube can be achieved, the design quality requirements of the helium tube weld can be met, and the welding process problem of welding the helium inlet and outlet tubes on the thin-walled superconducting cable armor can be effectively solved.

[0028] (2) In the present invention, the cooling device removes the heat from the welding area between the runway section and the superconducting cable through cooling water, so that the temperature of the superconducting cable does not exceed 200°C. The deformation of the runway section during the welding process is suppressed while ensuring the quality standard of the weld, and its design size requirements are met. Combined with the positioning function of the first fixing device, the deformation caused by welding is further alleviated, and the dimensional deviation after welding is reduced.

[0029] (3) In the present invention, the variable diameter transition section is assembled, pressed and positioned by the second fixing device, so as to control the deformation problem during welding of the variable diameter transition section and the runway section, and ensure that the design dimensional quality requirements are met after welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] Figure 1 It is a schematic structural diagram of the present invention using a thin-walled superconducting magnet helium tube welding tool to perform auxiliary welding on a runway section of a helium tube;

[0032] Figure 2 yes Figure 1 A schematic diagram of the structure of the cooling device;

[0033] Figure 3 yes Figure 2 Schematic diagram of the structural explosion of the cooling device;

[0034] Figure 4 yes Figure 1A schematic structural diagram of the first fixing device;

[0035] Figure 5 It is a schematic diagram of the structure of the helium tube of the present invention;

[0036] Figure 6 yes Figure 5 Schematic diagram of the structural explosion of the helium tube;

[0037] Figure 7 is a schematic structural diagram of a second fixing device of the present invention;

[0038] Figure 8 yes Figure 7 Schematic diagram of the structural explosion of the second fixing device;

[0039] Fig. 9 It is a structural schematic diagram of the present invention using a thin-walled superconducting magnet helium tube welding tool to perform auxiliary welding on a variable diameter transition section and a runway section of a helium tube;

[0040] Fig.10 It is a schematic diagram of the process flow of the thin-wall superconducting magnet helium tube welding process of the present invention.

[0041] In the figure:

[0042] 1. Superconducting cable; 2. Cooling device; 21. Bracket; 22. Cooling pipe; 23. Plug; 24. Water pipeline; 3. First fixing device; 31. First upper cover plate; 32. First lower cover plate; 33. Rear clamp; 34. Fastening bolts; 4. Second fixing device; 41. Second upper cover plate; 42. Second lower cover plate; 5. Helium tube; 51. Runway section; 52. Variable diameter transition section; 53. Extension tube; 6. Temperature measurement system; 61. Thermocouple; 62. Temperature controller; 63. Adhesive tape. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] See also Figure 1 , Figure 5-Figure 6 As shown, the present invention is a thin-wall superconducting magnet helium tube welding tool, which is suitable for welding a superconducting magnet and a helium tube 5. The superconducting magnet includes a superconducting cable 1, and a helium hole is opened at the armor inside the superconducting cable 1. The helium tube 5 includes a runway section 51, a diameter-changing transition section 52, and an extension tube 53. The helium tube 5 needs to be welded at the helium hole of the armor.

[0045] See also Figure 1 , Figure 4 As shown, the thin-wall superconducting magnet helium tube welding tool comprises: a first fixing device 3 , and the first fixing device 3 is used to fix the position of the runway section 51 .

[0046] Specifically, the first fixing device 3 includes two cover plates, namely a first upper cover plate 31 and a first lower cover plate 32. The first upper cover plate 31 and the first lower cover plate 32 are fixed to the superconducting cable 1 after being engaged, so that the superconducting cable 1 can pass through the wrapping structure composed of the two cover plates. The two cover plates after being engaged have through holes at positions corresponding to the armor helium holes of the superconducting cable 1 for positioning the runway section 51. The first upper cover plate 31 and the first lower cover plate 32 are fixedly mounted with a rear clamping plate 33, and the rear clamping plate 33 is connected with a fastening bolt 34.

[0047] For further information, see Figure 1-Figure 3 As shown, the first fixing device 3 is connected to the cooling device 2 , and the cooling device 2 is used to cool the welding area between the runway section 51 and the superconducting cable 1 .

[0048] The cooling device 2 includes a cooling pipe 22 extending into the helium hole. The runway section 51 is sleeved on the cooling pipe 22 . The cooling pipe 22 is penetrated by a bracket 21 . The bracket 21 is installed on the fastening bolts 34 .

[0049] The cooling pipe 22 is provided with a parallel double channel, and the end of each channel is connected to a water delivery pipe 24, and a plug 23 is provided at the tail end of the cooling pipe 22. The water delivery pipe 24 is connected to the cooling circulating water tank, so that cooling water can be continuously passed into the cooling pipe 22.

[0050] It should be noted that the water pipeline 24 and the bracket 21 in the cooling device 2 are made of stainless steel, the cooling pipe 22 and the plug 23 are made of TU1 material, and the various structures are welded and fixed by brazing technology.

[0051] See also Figure 1 As shown, the superconducting cable 1 is connected to a temperature measuring system 6 for monitoring the temperature of the superconducting cable 1 during welding. The temperature measuring system 6 includes a thermocouple 61, and the thermocouple 61 is electrically connected to a temperature controller 62. The thermocouple 61 is arranged on the upper and lower armor surfaces of the helium hole of the armor of the superconducting cable 1, and is 3 mm away from the armor surface of the helium hole surface, and is fixed with a tin foil tape 63.

[0052] In this embodiment, when welding the track section 51 and the superconducting cable 1, the track section 51 is first installed on the cooling pipe 22, and then the track section 51 is inserted into the armor helium hole of the superconducting cable 1, the first upper cover plate 31 and the first lower cover plate 32 are assembled on the superconducting cable 1, and the bracket 21 is fixed by fastening bolts 34 and rear clamping plates 33. At this time, the cooling device 2 is assembled on the first fixing device 3. The cooling circulating water tank and the welding power supply are turned on. During the welding process of the track section 51 and the superconducting cable 1, the cooling water flows continuously from the cooling circulating water tank into the cooling pipe 22, and the heat generated by welding is transferred from the track section 51 to the cooling water in the cooling pipe 22, so as to achieve the cooling of the welding area of ​​the track section 51 and the superconducting cable 1.

[0053] See also Figure 7-Figure 9 As shown, the thin-wall superconducting magnet helium tube welding tool further includes: a second fixing device 4, which is used to fix the position of the diameter-changing transition section 52 and the runway section 51 during welding.

[0054] Specifically, the second fixing device 4 includes two cover plates, namely, a second upper cover plate 41 and a second lower cover plate 42. The second upper cover plate 41 and the second lower cover plate 42 are fixed to the superconducting cable 1 after being engaged. The two cover plates after being engaged have through holes corresponding to the armor helium holes of the superconducting cable 1, which are used to locate the runway section 51. The two cover plates after being engaged also have a positioning hole coaxially with the armor helium holes of the superconducting cable 1, which are used to locate the variable diameter transition section 52. The second fixing device 4 is provided with a hole that passes through from top to bottom and serves as a welding operation area. The welding portion between the runway section 51 and the variable diameter transition section 52 is located in the welding operation area.

[0055] It is understandable that when the variable diameter transition section 52 is longer, the variable diameter transition section 52 is located at the positioning hole, and when the variable diameter transition section 52 is shorter, the extension tube 53 welded to the variable diameter transition section 52 is located at the positioning hole.

[0056] In this embodiment, the first fixture 3 or the second fixture 4 is mounted on the superconducting cable 1, so that the helium tube 5 can present two welding states, as follows:

[0057] See also Figure 1 As shown, in the first state, the first fixing device 3 and the cooling device 2 are assembled on the superconducting cable 1. At this time, the helium tube 5 has only the runway section 51, and the runway section 51 is located at the armor helium hole of the superconducting cable 1, where the runway section 51 is welded to the superconducting cable 1.

[0058] In the welding process of the helium tube 5, the current welding quality design requirements generally include the following points: when the runway section 51 is welded, the temperature of the superconducting cable 1 on the rear wall of the thin-walled armor cannot exceed 200°C; all welds require 100% VT, PT, RT non-destructive testing, and the testing requirements are the highest level of the corresponding standards. Helium mass spectrometry pressure leak detection is also required; the contour deformation size after welding is not greater than 0.5mm.

[0059] Since a lot of heat is generated during welding, the temperature of the superconducting cable 1 is relatively high, and the runway section 51 is prone to significant deformation at high temperatures. However, lowering the welding temperature cannot meet the quality standards of the weld.

[0060] In the present invention, cooling water is continuously injected into the cooling pipe 22 through the cooling device 2. The cooling water takes away the heat of the welding area between the runway section 51 and the superconducting cable 1 during the flow, so that the temperature of the superconducting cable 1 does not exceed 200°C. The deformation of the runway section 51 during the welding process is suppressed while ensuring the quality standard of the weld, and its design size requirements are guaranteed. In combination with the positioning function of the first fixing device 3, the deformation caused by welding is further alleviated, and the dimensional deviation after welding is reduced. It is also possible to combine with the temperature measuring system 6 to realize temperature-controlled welding, and adjust the flow rate of the cooling water according to the temperature. When the temperature measured by the thermocouple 61 is high, the cooling water flow rate is increased to accelerate the heat exchange. When the temperature measured by the thermocouple 61 is low, the cooling water flow rate is reduced to slow down the heat exchange.

[0061] See also Fig. 9 As shown, in the second state, the runway section 51 of the helium tube 5 has been welded and fixed at the armor helium hole of the superconducting cable 1, the first fixing device 3 and the cooling device 2 are removed from the superconducting cable 1, and the second fixing device 4 is assembled. At this time, the extension tube 53 is fixed by the positioning hole (the diameter-reducing transition section 52 of the helium tube 5 and the extension tube 53 have been welded in advance and formed a connection structure, and the diameter-reducing transition section 52 and the extension tube 53 adopt the tube-to-tube automatic welding technology, which belongs to the common welding process and is not described here), the diameter-reducing transition section 52 of the helium tube 5 and the runway section 51 at the helium hole are located on the same axis and abut against each other, and the diameter-reducing transition section 52 and the runway section 51 are welded at the abutment.

[0062] In the present application, the variable diameter transition section 52 is assembled, pressed and positioned by the second fixing device 4, so as to control the deformation problem during welding of the variable diameter transition section 52 and the runway section 51 and ensure that the design dimensional quality requirements are met after welding.

[0063] In another embodiment, see Fig.10 As shown, a thin-wall superconducting magnet helium tube welding process uses a thin-wall superconducting magnet helium tube welding tool for auxiliary welding.

[0064] The thin-wall superconducting magnet helium tube welding process includes:

[0065] The superconducting cable 1 , the first fixing device 3 and the cooling device 2 are assembled, and the runway section 51 is passed through the cooling device 2 and inserted into the helium hole of the armor of the superconducting cable 1 .

[0066] The runway section 51 is positioned by four-point spot welding, and then the TIG welding process is used to perform symmetrical segment welding on the upper and lower sides. During welding, the temperature is reduced by a cooling device 2 that has passed the inspection.

[0067] During the welding process between the runway section 51 and the superconducting cable 1 , the temperature of the superconducting cable 1 needs to be monitored by the temperature measuring system 6 .

[0068] After the track section 51 and the superconducting cable 1 are welded, the weld is inspected, and if the weld passes the inspection, the superconducting cable 1 welded with the track section 51 and the second fixing device 4 are assembled.

[0069] The diameter-changing transition section 52 and the runway section 51 are positioned by the second fixing device 4 and are welded by TIG welding process after positioning.

[0070] The specific steps are as follows:

[0071] S1. First, the extension tube 53 and the variable diameter transition section 52 of the helium tube 5 are welded by the automatic tube-to-tube welding technology, and are put into use after being tested and qualified. Then, the runway section 51 of the helium tube 5 is put on the cooling pipe 22 of the cooling device 2, and the water delivery pipeline 24 and the cooling circulating water tank are connected with a hose. Turn on the power to check whether there is water leakage in the cooling device 2. If there is water leakage, the cooling device 2 needs to be replaced. If there is no water leakage, continue to the next step.

[0072] S2. Three temperature measuring thermocouples 61 are arranged on the upper and lower armor surfaces of the armor helium hole of the superconducting cable 1, 3 mm away from the armor surface of the helium hole, and fixed with tin foil tape 63. The runway section 51 is installed on the water pipeline 24 and inserted into the armor helium hole of the superconducting cable 1. The first fixing device 3 is installed on the superconducting cable 1, and the cooling device 2 is fixed on the fastening bolt 34. The assembly is completed, and the helium tube 5 is in the first state.

[0073] S3. Turn on the cooling water tank and welding power supply, adjust the welding process parameters to perform four-point spot welding positioning on the runway section 51, and ensure that the groove assembly gap after spot welding is 2mm±0.3mm. Adjust the welding process parameters to weld the runway section 51. The welding process parameters are shown in Table 1. The TIG welding process is used for symmetrical segment welding on the upper and lower sides, and the welding time of each segment is controlled within two seconds (through welding tests, it is found that the welding heat input corresponding to the welding time within two seconds can keep the temperature of the superconducting cable 1 within 200°C during welding).

[0074] Table 1 Welding process parameters between runway section and superconducting cable

[0075]

[0076] S4. After the welding of the runway section 51 is completed, the first fixing device 3 and the cooling device 2 are removed, and then the weld is subjected to non-destructive, vacuum leak detection and appearance dimension detection. After the detection is qualified, the next step of welding between the variable diameter transition section 52 and the runway section 51 is carried out.

[0077] The second fixture 4 is assembled on the superconducting cable 1, and the variable diameter transition section 52 and the runway section 51 are positioned by the second fixture 4. After positioning, TIG welding is used to ensure that the assembly groove gap is 1mm to 3mm. The assembly is completed, and the helium tube 5 is in the second state.

[0078] S5. Adjust the welding process parameters to weld the variable diameter transition section 52 and the runway section 51. The welding process parameters are shown in Table 2. The welding adopts the TIG welding process. This weld does not need temperature control, so there is no need to assemble the cooling device 2.

[0079] Table 2 Welding process parameters of runway section and variable diameter transition section

[0080]

[0081] S6. After the welding is completed, the second fixing device 4 is removed, and the weld is subjected to nondestructive, leak detection and dimension detection. After the detection is qualified, the welding of the helium tube 5 is completed.

[0082] The welds are subjected to 100% VT, PT, and RT nondestructive testing, and the testing requirements are all the highest level of the standards corresponding to each weld. Helium mass spectrometry pressure leak detection is also performed. The specific test data are shown in Table 3.

[0083] Table 3 Nondestructive testing and pressurized helium mass spectrometry leak detection

[0084]

[0085] In the present invention, by using a thin-walled superconducting magnet helium tube welding tool and a thin-walled superconducting magnet helium tube welding process in cooperation with each other, the temperature-controlled welding of the helium tube 5 can be achieved, and the design quality requirements of the weld of the helium tube 5 can be met, which effectively solves the welding process problem of welding helium inlet and outlet tubes on thin-walled superconducting cable armor.

[0086] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of application of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A thin-walled superconducting magnet helium tube welding tool, suitable for welding a superconducting magnet and a helium tube (5), wherein the superconducting magnet comprises a superconducting cable (1), and the helium tube (5) comprises a runway section (51), a diameter-changing transition section (52), and an extension tube (53), characterized in that: include: A first fixing device (3), the first fixing device (3) being used to fix the position of the runway section (51); A cooling device (2), the cooling device (2) being used to cool a welding area between the runway section (51) and the superconducting cable (1); A second fixing device (4), the second fixing device (4) being used to fix the position of the diameter-changing transition section (52) and the runway section (51) during welding; The first fixing device (3) or the second fixing device (4) is installed on the superconducting cable (1) so that the helium tube (5) can present two welding states; In a first state, the runway section (51) is located at the armor helium hole of the superconducting cable (1); In the second state, the diameter-changing transition section (52) and the racetrack section (51) at the helium hole are located on the same axis and abut against each other.

2. The thin-walled superconducting magnet helium tube welding tool according to claim 1, characterized in that: The first fixing device (3) comprises two cover plates, which are fixed to the superconducting cable (1) after being clamped together, and the two clamped cover plates have through holes at positions corresponding to the armor helium holes of the superconducting cable (1) for positioning the runway section (51).

3. A thin-walled superconducting magnet helium tube welding tool according to claim 2, characterized in that: The two cover plates are fixedly mounted with a rear clamping plate (33), and the rear clamping plate (33) is connected with a fastening bolt (34).

4. The thin-walled superconducting magnet helium tube welding tool according to claim 3, characterized in that: The cooling device (2) comprises a cooling pipe (22) extending into the helium hole, the runway section (51) is sleeved on the cooling pipe (22), the cooling pipe (22) is penetrated by a bracket (21), and the bracket (21) is mounted on the fastening bolt (34).

5. The thin-walled superconducting magnet helium tube welding tool according to claim 4, characterized in that: The cooling pipeline (22) is provided with two parallel channels, and the end of each channel is connected to a water delivery pipeline (24), and a plug (23) is provided at the tail end of the cooling pipeline (22).

6. The thin-walled superconducting magnet helium tube welding tool according to claim 1, characterized in that: The second fixing device (4) comprises two cover plates, which are fixed to the superconducting cable (1) after being clamped together. The two cover plates after being clamped together have through holes at positions corresponding to the armor helium holes of the superconducting cable (1) for positioning the runway section (51). The two cover plates after being clamped together also have a positioning hole in the coaxial direction of the armor helium holes of the superconducting cable (1) for positioning the variable-diameter transition section (52).

7. A thin-walled superconducting magnet helium tube welding tool according to claim 6, characterized in that: The second fixing device (4) is provided with a hole which passes through from top to bottom and serves as a welding operation area, and the welding portion between the runway section (51) and the diameter-changing transition section (52) is located within the welding operation area.

8. The thin-walled superconducting magnet helium tube welding tool according to claim 1, characterized in that: The superconducting cable (1) is connected to a temperature measurement system (6), the temperature measurement system (6) comprises a thermocouple (61), and the thermocouple (61) is electrically connected to a temperature controller (62).

9. A thin-wall superconducting magnet helium tube welding process, characterized in that: The thin-walled superconducting magnet helium tube welding tool according to any one of claims 1 to 8 comprises: Assembling the superconducting cable (1), the first fixing device (3) and the cooling device (2), passing the runway section (51) through the cooling device (2) and inserting it into the helium hole of the armor of the superconducting cable (1); The runway section (51) is positioned by four-point spot welding, and then the TIG welding process is used to perform symmetrical segment welding on the upper and lower sides. During welding, the temperature is reduced by a cooling device (2) that has passed the inspection; After the runway section (51) and the superconducting cable (1) are welded, the weld is inspected, and after passing the inspection, the superconducting cable (1) welded with the runway section (51) is assembled with the second fixing device (4); The diameter-changing transition section (52) and the runway section (51) are positioned by means of a second fixing device (4), and after positioning, they are welded using a TIG welding process.

10. A thin-walled superconducting magnet helium tube welding process according to claim 9, characterized in that: During the welding process between the runway section (51) and the superconducting cable (1), the temperature of the superconducting cable (1) needs to be monitored by a temperature measuring system (6).

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