Method of welding superconducting cable armour tube

Abstract

The present application relates to the technical field of welding, and particularly discloses a welding method for superconducting cable armor pipes, which is based on a welding tool. The support tool in the welding tool supports the armor pipes to be welded. The gas outlet pipe of the back gas tool supplies protective gas to the back of the weld joint during the welding process. The welding method comprises the following steps: placing two armor pipes to be welded on the support tool, with the surfaces to be welded of the two armor pipes arranged opposite to each other along a first direction; arranging a plugging piece on the first end to block the first end; inserting at least part of the back gas tool into the armor pipe through the second end; supplying gas towards the surfaces to be welded by the back gas tool; equally dividing the backing layer and the cover layer of the surfaces to be welded into multiple sectors; and welding the sectors of the backing layer and the cover layer by using a pulse welding process and a non-pulse welding process respectively. The welding current is reduced by 1A-3A after the welding of each sector is completed. The welding quality of the armor pipe is improved.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a welding method for a superconducting cable armor tube. Background Technology

[0002] Low-temperature superconducting magnets are an important component in low-temperature nuclear fusion devices. They can continuously generate high-intensity steady-state or pulsed magnetic fields to achieve magnetic confinement, shape control, and positional stability of high-temperature plasma, prevent plasma from contacting the inner wall of the device, and maintain the stable progress of the fusion reaction.

[0003] Low-temperature superconducting magnets typically consist of structures such as superconducting cables, cladding, and armored tubes. Under fusion conditions, the superconducting cables carry large currents and are in a strong magnetic field, which generates huge Lorentz forces and circumferential / radial stresses. The armored tubes, as high-strength load-bearing structures, can absorb and disperse mechanical loads to prevent deformation and crush damage to the superconducting cables.

[0004] Currently, armored tubes are generally made of 316L stainless steel tubes through welding, tube shrinking, and straightening to produce the size and shape required for superconducting magnets. Superconducting cables generally have a certain length, but the length of a single stainless steel tube that can be purchased on the market is insufficient to meet the length required for a single superconducting cable. Therefore, welding is usually used to connect several stainless steel tubes together to meet the length required for a single superconducting cable.

[0005] However, existing technology is not suitable for specifications of φ17. +0.10 ×1 +0.1mm The armored tubes, made of 316L stainless steel, suffer from poor welding quality between the tubes, resulting in a low welding pass rate. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a welding method for superconducting cable armor tubes, which can improve the welding quality of the armor tubes, increase the welding qualification rate of the armor tubes, and solve the problem of poor welding quality between armor tubes in the prior art.

[0007] According to an embodiment of the present invention, a welding method for a superconducting cable armor tube is provided. The welding method is based on a welding fixture, which includes a support fixture and a back gas shielding fixture. The support fixture supports the armor tube to be welded, and the back gas shielding fixture includes an exhaust pipe for supplying shielding gas to the back side of the weld during the welding process. The welding method includes the following steps: placing two armor tubes to be welded on the support fixture, with the surfaces to be welded of the two armor tubes facing each other along a first direction; defining the end of one armor tube facing away from the surface to be welded as a first end, and the end of the other armor tube facing away from the surface to be welded as a second end; and providing a sealing element on the first end to seal it. The first end is blocked; at least a portion of the back gas-insulating tool is inserted into the armored tube through the second end, and the gas outlet pipe is positioned directly opposite the welding surfaces of the two armored tubes; gas is supplied to the welding surfaces through the back gas-insulating tool; the welding surfaces are divided into a base layer and a top layer, and the base layer and the top layer are equally divided into multiple sectors arranged sequentially along their circumference; the multiple sectors of the base layer are welded sequentially using a pulse welding process; the multiple sectors of the top layer are welded sequentially using a non-pulse welding process; wherein, during the sequential welding of the multiple sectors of the base layer and the top layer, the welding current is reduced by 1A to 3A after each sector is welded.

[0008] According to the welding method of the superconducting cable armor tube according to embodiments of the present invention, by setting the welding fixture to include a support fixture and a back gas shielding fixture, not only can the support fixture effectively support the armor tube and ensure the positional stability of the armor tube, thereby ensuring the stability of the armor tube during welding, but the back gas shielding fixture can also deliver protective gas to the back of the weld during the welding process to effectively protect the back of the weld, thereby facilitating the good formation of the back of the weld and improving the welding strength between the armor tubes. In other words, the welding method of the superconducting cable armor tube based on the above-mentioned welding fixture can improve the welding quality of the armor tube and increase the welding qualification rate of the armor tube.

[0009] In some embodiments, the welding start point of both the base layer and the top layer is set at the six o'clock position on the surface to be welded, and the two armored tubes are welded in a counterclockwise direction.

[0010] In some embodiments, the root pass is divided into six sectors arranged sequentially along its circumference. When the six sectors of the root pass are sequentially welded using a pulse welding process, the welding currents for the six sectors are 33.5A, 31.5A, 28.5A, 27.5A, 25.4A, and 23.6A, respectively. The welding time for each sector is 4.87s, the welding speed is 2.05mm / s, the high pulse time is 0.2s, the low pulse time is 0.2s, and the shielding gas used for welding is a first... Argon gas, the flow rate of the first argon gas is 15 L / min; the cover layer is divided into six sectors arranged sequentially along its circumference; when the six sectors of the cover layer are welded sequentially using a non-pulse welding process, the welding currents of the six sectors are 22A, 21A, 20A, 19A, 18A and 17A respectively; the welding time of each sector is 4.35s; the welding speed is 2.3mm / s; the shielding gas for welding is a second argon gas, the flow rate of the second argon gas is 15 L / min.

[0011] In some embodiments, the back gas-insulating fixture is used to deliver a third argon gas toward the surface to be welded, the flow rate of the third argon gas being 5 L / min.

[0012] In some embodiments, before dividing the surface to be welded into two layers, a base layer and a cover layer, and dividing the base layer and the cover layer into multiple sectors arranged sequentially along their circumference, the method further includes the following step: using an instant spot welding process to spot weld and fix the two armored tubes.

[0013] In some embodiments, the welding fixture further includes a weld inspection gauge, which is used to inspect the back reinforcement height of the weld after welding is completed. The welding method further includes the following steps: after the weld cools to room temperature, the back gas shielding fixture is closed and pulled out; the back reinforcement height of the weld is inspected using the weld inspection gauge and it is determined whether the weld meets the weld reinforcement quality requirements; if yes, the welding is completed; if no, the weld is cut off, and at least a portion of the back gas shielding fixture is inserted into the armored tube through the second end to re-weld the two armored tubes.

[0014] In some embodiments, the support fixture includes a support plate and a plurality of support components, the plurality of support components being spaced apart on the support plate along the first direction, and each armored tube being simultaneously disposed on at least two of the support components.

[0015] In some embodiments, the support assembly includes a support block, a pressure block, and a fastener. The pressure block is detachably connected to the top of the support block via the fastener. The support block has a first groove on one side facing the pressure block, and the pressure block has a second groove on one side facing the support block, which is opposite to the first groove. The first groove and the second groove cooperate to form an assembly hole. The armor tube passes through the assembly hole, and the diameter of the assembly hole is smaller than the outer diameter of the armor tube.

[0016] In some embodiments, the coaxiality of the mounting holes on two adjacent support components is less than or equal to 0.05 mm.

[0017] In some embodiments, placing the two armored tubes to be welded on the support fixture includes the following steps: placing the armored tubes on the support block, with a radial portion of the armored tubes positioned within the first groove; assembling the pressure block on the top of the support block, with another radial portion of the armored tubes positioned within the second groove; pre-fixing the pressure block using the fasteners; axially moving the armored tubes; and fixing the pressure block to the support block using the fasteners.

[0018] In some embodiments, the sealing element is an aluminum plate, which is disposed at the first end and bonded to the armored tube, and the aluminum plate is provided with a plurality of vent holes.

[0019] In some embodiments, the back gas-insulating fixture includes a gas supply pipe and a rubber component. The gas supply pipe is connected to the gas outlet pipe and is used to supply gas toward the gas outlet pipe. The rubber component is fixedly connected to both axial ends of the gas outlet pipe and is adapted to have an interference fit with the inner circumferential wall of the armored tube.

[0020] In some embodiments, the vent pipe is provided with a plurality of vents, and the plurality of vents are arranged sequentially at intervals along the circumference and axial direction of the vent pipe; wherein the diameter of the vent is 1mm to 2mm; and / or, in the axial direction of the vent pipe, the minimum distance between two adjacent vents is 4mm to 6mm.

[0021] Additional aspects and advantages of the invention will become apparent from the description which follows, or may be learned by practice of the invention. Attached Figure Description

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0023] Figure 1 This is a flowchart illustrating the steps of a welding method for a superconducting cable armor tube according to some embodiments of the present invention.

[0024] Figure 2 This is a schematic diagram of the support fixture and armored tube according to some embodiments of the present invention;

[0025] Figure 3 This is a schematic diagram of a back-mounted gas-insulating tooling according to some embodiments of the present invention;

[0026] Figure 4 This is a schematic diagram of a weld inspection gauge according to some embodiments of the present invention;

[0027] Figure 5 This is a side view of the armored tube according to some embodiments of the present invention;

[0028] Figure 6 The following is a flowchart showing the detailed steps of the welding method for the superconducting cable armor tube according to some embodiments of the present invention.

[0029] Figure 7 This is a schematic diagram showing the omitted parts of the supporting tooling structure in some embodiments of the present invention;

[0030] Figure 8 This is a schematic diagram of a pressing block according to some embodiments of the present invention;

[0031] Figure 9 This is a table of welding process parameters for multiple sectors of the bottom layer in some embodiments of the present invention;

[0032] Figure 10 This is a table of welding process parameters for multiple sectors of the cover layer in some embodiments of the present invention.

[0033] Figure label:

[0034] 1000, Armored tube; 100, First end; 200, Second end; 300, Sector;

[0035] 1100. Supporting fixtures;

[0036] 1110. Support plate;

[0037] 1120. Support components;

[0038] 1121, Support block; 1124, First groove; 1127, Second mounting hole;

[0039] 1122, Pressure block; 1125, Second groove; 1126, First mounting hole;

[0040] 1123. Fasteners;

[0041] 1130. Assembly hole;

[0042] 1200, back-mounted air-cushioning tooling;

[0043] 1210. Air outlet pipe; 1211. Air outlet;

[0044] 1220. Gas pipeline;

[0045] 1230. Rubber parts;

[0046] 1240. Fasteners;

[0047] 1300, Weld inspection gauge; 1310, Gauge; 1320, Support pipe. Detailed Implementation

[0048] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] The welding method of the superconducting cable armor tube 1000 according to an embodiment of the present invention is described below with reference to the accompanying drawings.

[0051] The welding method is based on a welding fixture and combines... Figure 1 , Figure 2 and Figure 3 As shown, the welding fixture includes a support fixture 1100 and a back gas shielding fixture 1200. The support fixture 1100 is used to support the armored tube 1000 to be welded, and the back gas shielding fixture 1200 includes an exhaust pipe 1210, which is used to deliver protective gas to the back side of the weld during the welding process.

[0052] Combination Figures 1-5 As shown, a welding method for a superconducting cable armor tube 1000 according to an embodiment of the present invention includes:

[0053] S1. Place the two armored tubes 1000 to be welded on the support fixture 1100, and set the welding surfaces of the two armored tubes 1000 opposite each other along the first direction.

[0054] Since the support fixture 1100 is used to support the armored tubes 1000 to be welded, the above steps achieve the initial positioning and installation of the two armored tubes 1000, which can ensure the positional stability of the armored tubes 1000, thereby ensuring the stability of the armored tubes 1000 during welding. Furthermore, by setting the surfaces of the two armored tubes 1000 to be welded opposite each other along the first direction, the surfaces of the two armored tubes 1000 to be welded are at the same height on the support fixture 1100, which facilitates the subsequent welding work on the surfaces of the two armored tubes 1000.

[0055] It should be noted that the specific extension direction of the first direction can be found in [reference needed]. Figure 2 .

[0056] S2. Define the end of one armored tube 100 that is away from the surface to be welded as the first end 100, and the end of the other armored tube 100 that is away from the surface to be welded as the second end 200. Set a sealing element (not shown in the figure) on the first end 100 to seal the first end 100.

[0057] In the above steps, sealing the first end 100 can prevent a large amount of gas from being lost from the first end 100 when the back gas-insulating tool 1200 delivers gas toward the surface to be welded. This is conducive to quickly establishing a protective gas layer, facilitating subsequent welding of the surface to be welded, while also saving gas and reducing the welding cost of the armored tube 1000 to a certain extent.

[0058] In some embodiments, the sealing element may be a sealing block, which may be formed as a plastic part or an elastic part, etc.

[0059] S3. Insert at least a portion of the back gas-insulating fixture 1200 into the armored tube 1000 through the second end 200, and set the vent pipe 1210 facing the two armored tubes 1000 to be welded.

[0060] In other words, when at least a portion of the back gas shielding fixture 1200 extends into the armored tube 1000 through the second end 200, the gas outlet pipe 1210 of the back gas shielding fixture 1200 is positioned directly opposite the welding surfaces of the two armored tubes 1000. Since the gas outlet pipe 1210 is used to supply protective gas to the back side of the weld during the welding process, the back side of the weld can be effectively protected during the welding process in the above steps, which is conducive to the good formation of the back side of the weld, thereby improving the welding strength and welding quality between the armored tubes 1000.

[0061] In some embodiments, the protective gas supplied by the vent pipe 1210 to the back side of the weld during the welding process is an inert gas such as argon or helium. Since the inert gas is chemically very stable and does not participate in the welding metallurgical reaction, by supplying the protective gas to the back side of the weld, it is possible to isolate oxygen, nitrogen and other gases from the back side of the weld, prevent the back side of the weld from being oxidized and nitrided at high temperatures, and ensure the welding reliability of the armored tube 1000.

[0062] S4. Gas is delivered toward the surface to be welded via the back gas-insulating fixture 1200.

[0063] In the above steps, the back side of the weld can be protected by gas, thereby preventing the back side of the weld from being oxidized and nitrided at high temperatures, thus ensuring the welding stability of the armored tube 1000.

[0064] In some embodiments, before at least a portion of the back gas-insulating tool 1200 is inserted into the armored tube 1000 through the second end 200, the outer wall surface of the armored tube 1000 at the surface to be welded and the inner wall surface of the armored tube 1000 30mm away from the surface to be welded are cleaned with anhydrous ethanol or acetone, etc., to remove organic and impurity contaminants such as oil, grease, cutting fluid, dust, fingerprints, sweat stains and oxide powder, so as to avoid the decomposition of oil and organic matter at the high welding temperature to produce hydrogen and carbon oxides, and further avoid the formation of porosity, cracks and slag inclusions in the weld, thereby ensuring the weld tightness and airtightness of the armored tube 1000 and improving the welding quality of the armored tube 1000.

[0065] In some embodiments, after at least a portion of the back gas-insulating fixture 1200 is inserted into the armor tube 1000 through the second end 200, the outer wall of the armor tube 1000 at the welding surface is cleaned again using anhydrous ethanol or acetone. As the back gas-insulating fixture 1200 delivers gas toward the welding surface, the airflow carries out the internal dust, oxide scale, and metal shavings of the armor tube 1000, some of which will adhere to the welding surface. The second cleaning can completely remove these residual solid impurities, thereby preventing slag inclusions and porosity from being drawn into the weld when welding the welding surface.

[0066] S5. Divide the surface to be welded into a base layer and a cover layer, and divide the base layer and the cover layer into multiple sectors 300 arranged sequentially along their circumference.

[0067] The above steps can avoid making each sector 300 too long, which makes it easier to weld the bottom layer and top layer separately, and helps to ensure the welding quality between the two armor tubes 1000.

[0068] S6. The pulse welding process is used to sequentially weld multiple sectors 300 of the bottom layer.

[0069] In the above steps, the pulse welding process is used to weld multiple sectors 300 of the bottom layer in sequence, so that the heat input (current) is precisely controllable. This results in small deformation and heat-affected zone between armor tubes 1000, and high weld quality between multiple sectors 300 of the bottom layer, thereby improving the welding quality of the bottom layer.

[0070] It should be noted that pulse welding process usually refers to intermittent heating, that is, the welding current is not constant, but alternates between high current (peak value) and low current (base value) for a period of time, and the current changes dozens to hundreds of times per second. It has the characteristics of thorough weld melting, but low overall heat input.

[0071] S7. The multiple sectors 300 of the cover layer are welded sequentially using a non-pulse welding process.

[0072] In the above steps, since the amount of welding in the cover layer is generally larger than that in the base layer, and the welding deformation control requirements for the cover layer are lower than those for the base layer, under the premise of ensuring the weld quality of the base layer, the non-pulse welding process is used to weld multiple sectors 300 of the cover layer in sequence. This method is highly convenient to operate. At the same time, the heat input of the cover layer is continuous and stable, which makes it easier to increase the welding speed of the cover layer.

[0073] It should be noted that non-pulse welding processes are typically constant DC or constant AC, meaning the current output is stable and there is no switching between pulse frequency and peak base value. They are characterized by simple operation, fast welding speed for long welds, and high welding efficiency.

[0074] In a specific example, the pulse welding process is used to weld multiple sectors 300 of the bottom layer sequentially, and the non-pulse welding process is used to weld multiple sectors 300 of the top layer sequentially. This can meet the quality requirement that the back reinforcement height of the weld between the armored tubes 1000 is less than 0.1mm.

[0075] During the sequential welding of multiple sectors 300 of the underlayer and cover layer, the welding current is reduced by 1A to 3A after each sector 300 is welded. This setting effectively reduces heat input, thereby lowering the temperature, volume, and fluidity of the molten pool, resulting in better control of the molten pool and ultimately ensuring the weld formation quality of the armored tube 1000, avoiding various defects.

[0076] Specifically, after each 300mm sector is welded, the welding current is reduced by 1A, 1.1A, 1.2A, 1.3A, 1.4A, 1.5A, 1.6A, 1.7A, 1.8A, 1.9A, 2A, 2.1A, 2.2A, 2.3A, 2.4A, 2.5A, 2.6A, 2.7A, 2.8A, 2.9A, or 3A.

[0077] As can be seen from the above structure, the welding method of the superconducting cable armor tube 1000 in this embodiment of the invention, by setting the welding fixture to include a support fixture 1100 and a back gas shielding fixture 1200, can not only effectively support the armor tube 1000 using the support fixture 1100 to ensure the positional stability of the armor tube 1000, thereby ensuring the stability of the armor tube 1000 during welding, but also allow the back gas shielding fixture 1200 to deliver protective gas to the back of the weld during the welding process of the armor tube 1000, so as to effectively protect the back of the weld, thereby facilitating the good formation of the back of the weld and improving the welding strength between the armor tubes 1000.

[0078] In other words, the welding method for the superconducting cable armor tube 1000 is based on the above-mentioned welding fixture, which can improve the welding quality of the armor tube 1000 and increase the welding qualification rate of the armor tube 1000.

[0079] Understandably, compared to existing technologies, this application can guarantee the welding quality of the armored tube 1000 and improve the welding qualification rate of the armored tube 1000.

[0080] In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0081] In some embodiments, such as Figure 5 As shown, the starting point for both the base layer and the top layer welding is set at the six o'clock position on the surface to be welded, and the two armored tubes 1000 are welded in a counterclockwise direction. This ensures that the flow direction of the welding needle and the molten iron generated by the welding heat is consistent during the initial welding stage (from the six o'clock position to the four o'clock position), thus facilitating the welding of the two armored tubes 1000 by utilizing heat conduction and ensuring welding quality.

[0082] In some embodiments, combined with Figure 5 and Figure 9 As shown, the root pass is divided into six sectors 300 arranged sequentially along its circumference. When the six sectors 300 of the root pass are welded sequentially using a pulse welding process, the welding currents for the six sectors 300 are 33.5A, 31.5A, 28.5A, 27.5A, 25.4A, and 23.6A, respectively. The welding time for each sector 300 is 4.87s, the welding speed is 2.05mm / s, the high pulse time is 0.2s, the low pulse time is 0.2s, and the shielding gas is argon gas with a flow rate of 15L / min. This method aims to improve the welding quality between the six sectors 300 of the root pass, thereby enhancing the overall welding quality of the root pass.

[0083] Dividing the base coat into six sectors 300 arranged sequentially along its circumference can be understood as the surface to be welded being a 360° circular surface, with each sector 300 representing 60°. Therefore, dividing the base coat into six sectors 300 arranged sequentially along its circumference means that 0~60° is the first sector 300. Figure 9 In section 1-1, from the 6 o'clock position to the 4 o'clock position, the welding current is 33.5A; 60°~120° is the second sector 300, corresponding to... Figure 9 In the section 1-2, i.e., from the four o'clock position to the two o'clock position, the welding current is 31.5A; 120°~180° is the third sector 300, corresponding to... Figure 9 In the section 1-3, i.e., from the 2 o'clock position to the 12 o'clock position, the welding current is 28.5A; 180°~240° is the fourth sector 300, corresponding to... Figure 9 In the section 1-4, i.e., from the 12 o'clock position to the 10 o'clock position, the welding current is 27.5A; 240°~300° is the fifth sector, 300°, corresponding to... Figure 9 In the section 1-5, i.e., from the 10 o'clock position to the 8 o'clock position, the welding current is 25.4A; 300°~360° is the sixth sector 300, corresponding to... Figure 9 For sections 1-6, i.e., from the 8 o'clock position to the 6 o'clock position, the welding current is 23.6A.

[0084] In summary, the current difference between segment 1-1 and segment 1-2 is 2A, the current difference between segment 1-2 and segment 1-3 is 3A, the current difference between segment 1-3 and segment 1-4 is 1A, the current difference between segment 1-4 and segment 1-5 is 2.1A, and the current difference between segment 1-5 and segment 1-6 is 1.8A.

[0085] It should also be noted that, such as Figure 9 As shown, the pulse ratio of segments 1-1, 1-2, 1-3, 1-4, 1-5, and 1-6 is 30%. The ratio of this application is relatively small, which means that the high current time of the six sectors 300 when welding the bottom layer is short, the heat is concentrated, the heat dissipation is fast, and the deformation is small. This can reduce the welding stress and the armor tube 1000 has good welding quality. Among them, the pulse ratio refers to the percentage of the high current pulse time in a pulse cycle to the total cycle time.

[0086] Meanwhile, the shielding gas for welding is argon gas, with a flow rate of 15L / min. This argon gas can isolate the welding arc, molten pool, and air, preventing oxygen and nitrogen from entering the root pass weld. This can prevent porosity and cracks in the root pass weld, thereby improving the welding quality of the root pass.

[0087] By setting the above, the heat input value during welding between the six sectors 300 of the bottom layer can be reduced, making it easier to control thermal deformation and thus improving the welding quality of the bottom layer.

[0088] In some embodiments, combined with Figure 5 and Figure 10 As shown, the cover layer is divided into six sectors 300 arranged sequentially along its circumference. When the six sectors 300 of the cover layer are welded sequentially using a non-pulse welding process, the welding currents for the six sectors 300 are 22A, 21A, 20A, 19A, 18A, and 17A, respectively. The welding time for each sector 300 is 4.35s, the welding speed is 2.3mm / s, and the shielding gas is a second argon gas with a flow rate of 15L / min. This method aims to improve the welding quality between the six sectors 300 of the cover layer, thereby enhancing the overall welding quality of the cover layer.

[0089] Dividing the cover layer into six sectors 300 arranged sequentially along its circumference can be understood as the surface to be welded being a 360° circular surface, with each 60° segment being a sector 300. Therefore, the cover layer is divided into six sectors 300 arranged sequentially along its circumference, with 0° to 60° being the seventh sector 300. Figure 10 In section 2-1, from the 6 o'clock position to the 4 o'clock position, the welding current is 22A; 60°~120° corresponds to the eighth sector, 300. Figure 10 In section 2-2, from the 4 o'clock position to the 2 o'clock position, the welding current is 21A; 120°~180° corresponds to the ninth sector, 300. Figure 10 In the section 2-3, from the 2 o'clock position to the 12 o'clock position, the welding current is 20A; 180°~240° corresponds to the tenth sector, 300°. Figure 10 In the section 2-4, i.e., from the 12 o'clock position to the 10 o'clock position, the welding current is 19A; 240°~300° is the eleventh sector, 300°, corresponding to... Figure 10 In the section 2-5, i.e., from the 10 o'clock position to the 8 o'clock position, the welding current is 18A; 300°~360° is the twelfth sector, 300°, corresponding to... Figure 10 For sections 2-6, i.e., from the 8 o'clock position to the 6 o'clock position, the welding current is 17A.

[0090] In summary, the current difference between segments 2-1 and 2-2, 2-2 and 2-3, 2-3 and 2-4, 2-4 and 2-5, and 2-5 and 2-6 is 1A.

[0091] Meanwhile, the shielding gas for welding is a second argon gas with a flow rate of 15L / min. This second argon gas can isolate the welding arc, molten pool and air, preventing oxygen and nitrogen from entering the weld of the capping layer. This can prevent porosity and cracks in the weld of the capping layer, thereby improving the welding quality of the capping layer.

[0092] The above settings can reduce the heat input value during welding between the six sectors 300 of the cover layer, making it easier to control thermal deformation and thus improve the welding quality of the cover layer.

[0093] In summary, by setting the welding process parameters for the multiple sectors 300 of the bottom layer and the multiple sectors 300 of the top layer, and by welding adjacent armor tubes 1000 according to the welding process parameters, the welding quality of the surface to be welded of the armor tubes 1000 can be improved, and the quality requirement that the back reinforcement of the weld between the armor tubes 1000 is less than 0.1mm can be achieved.

[0094] In some embodiments, the back gas protection fixture 1200 is used to deliver a third argon gas toward the surface to be welded, with a flow rate of 5 L / min. This is to protect the back side of the weld, isolate it from oxygen, nitrogen, and other gases, prevent oxidation and nitriding of the back side of the weld at high temperatures, and ensure the welding stability of the armored tube 1000.

[0095] In the description of this invention, features defined as "first," "second," and "third" may explicitly or implicitly include one or more of these features, used to distinguish and describe features, without any order or emphasis.

[0096] In some embodiments, combined with Figure 1 and Figure 6 As shown, before dividing the surface to be welded into two layers, a base coat and a cover coat, and before equally dividing the base coat and cover coat into multiple sectors 300 arranged sequentially along their circumference, the following steps are also included:

[0097] S05. The two armored tubes 1000 are fixed by spot welding using an instant spot welding process.

[0098] The above steps are used to achieve preliminary welding and fixing of the two armor tubes 1000, so as to avoid displacement, deviation and misalignment of the two armor tubes 1000 during the subsequent formal welding of the bottom layer and the top layer. To a certain extent, this can improve the welding effect of the armor tubes 1000 and reduce the difficulty of subsequent formal welding of the bottom layer and the top layer.

[0099] In some embodiments, the instantaneous spot welding process uses argon arc welding, with a welding current of 35 A and an arc voltage ranging from 7 V to 10 V. During the spot welding process, it is necessary to avoid piercing the back of the surface to be welded, so as to ensure the forming quality of the root weld of the surface to be welded, avoid repair welding perforation and root cleaning and grinding, and reduce the repair cost of the armor pipe 1000.

[0100] In a specific example, the specific welding process of the armor pipe 1000 is as follows: when at least part of the back gas protection tooling 1200 extends into the armor pipe 1000 through the second end 200 and the gas outlet pipe 1210 is set facing the surfaces to be welded of the two armor pipes 1000, open the back gas protection gas cylinder and the flowmeter and introduce the third argon gas into the interior of the armor pipe 1000 through the gas outlet pipe 1210. After 5 minutes, turn on the manual TIG welder (tungsten inert gas welder) and related equipment and perform pre-welding inspections. After confirming that there are no problems, adjust the welding process parameters to perform spot welding and fixation on the surfaces to be welded of the two armor pipes 1000. Adopt the instantaneous spot welding process method and prevent the back of the surface to be welded from being pierced during the spot welding process.

[0101] Subsequently, after the spot welding preliminarily fixes the surfaces to be welded of the two armor pipes 1000, check whether the two armor pipes 1000 are aligned. After the two armor pipes 1000 are aligned, perform pipe-to-pipe welding, that is, sequentially weld multiple sectors 300 of the backing layer and multiple sectors 300 of the cover layer. Turn on the pipe-to-pipe automatic welder and related equipment to call out the welding process parameters of the armor pipe 1000 ( Figure 9 and Figure 10 ) corresponding program, assemble the welding torch to the surface to be welded, adjust the tungsten electrode to be centered on the middle of the surface to be welded, and adjust the height between the tungsten electrode and the surface to be welded. Then clamp the welding torch and perform pre-welding inspections. After there are no problems, press the automatic welding switch to start welding. Pay attention to observation during the process. If welding abnormalities occur, immediately press the emergency stop button of the welder to pause welding, and continue welding only after eliminating the abnormalities; after the backing layer and the cover layer welding are completed, use a stainless steel wire brush to remove the oxide layer on the weld, and after visual self-inspection is qualified, the welding is completed.

[0102] It should be noted that through the above welding method, the present application can realize an automatic welding production manufacturing process, improve the production efficiency of the armor pipe 1000, save the manufacturing cost of the armor pipe 1000 to a certain extent, and can shorten the production cycle of the armor pipe 1000.

[0103] In some embodiments, as shown in combination with Figure 1 、 Figure 4 and Figure 6 , the welding tooling further includes a weld detection plug gauge 1300, and the weld detection plug gauge 1300 is used to detect the back height of the weld after welding. The welding method further includes the following steps:

[0104] S8. After the weld seam cools to room temperature, close and pull out the back gas-insulating fixture 1200.

[0105] The above steps ensure the formation effect of the weld and prevent the back gas shielding fixture 1200 from affecting the weld inspection gauge 1300's inspection of the back reinforcement of the weld.

[0106] S9. Use weld inspection gauge 1300 to inspect the back reinforcement of the weld and determine whether the weld meets the weld reinforcement quality requirements; if yes, the welding is completed; if no, cut off the weld and extend at least part of the back gas shielding fixture 1200 into the armored tube 1000 through the second end 200 to re-weld the two armored tubes 1000.

[0107] By following the above steps, the finished product qualification rate of Armored Tube 1000 can be guaranteed.

[0108] It should be noted that the above steps can be understood as follows: if the weld meets the weld quality requirements, the welding of the two 1000-gauge armored pipes is complete; if the weld does not meet the weld quality requirements, it needs to be repeated according to the steps above. Figure 1 and Figure 6 Weld according to the steps shown until the weld meets the high quality requirements.

[0109] It should also be noted that, through the above steps, the pass rate of the armored tube 1000 after welding is over 98%.

[0110] In some embodiments, such as Figure 4 As shown, the weld inspection gauge 1300 includes a gauge 1310 and a support tube 1320. The gauge 1310 is fixedly connected to the support tube 1320. The gauge 1310 is used to inspect the back reinforcement of the weld. The support tube 1320 extends towards the end opposite to the gauge 1310. Fixing the gauge 1310 to the support tube 1320 allows the support tube to support the gauge 1310, ensuring the stability of its movement. Simultaneously, extending the support tube 1320 towards the end opposite to the gauge 1310 provides a certain length, facilitating the insertion of the gauge 1310 into the weld. The support tube 1320 also reduces the difficulty for the gauge 1310 in inspecting the back reinforcement of the weld.

[0111] In some embodiments, the cylindrical diameter of the general gauge 1310 is typically 14.81 mm to 14.88 mm, and the support tube 1320 is a pipe with a specification of φ6 mm × 1 mm and a length greater than 10000 mm.

[0112] In a specific example, the gauge 1310 is inserted into the armored tube 1000 using the support tube 1320. If the gauge 1310 can pass through the back of the weld without obstruction, the weld of the armored tube 1000 meets the quality requirement of weld reinforcement height being less than 0.1 mm. If the gauge 1310 cannot pass through the back of the weld, the weld does not meet the quality requirement of weld reinforcement height, and the weld needs to be cut off. At least a portion of the back gas-insulating tool 1200 is then inserted into the armored tube 1000 through the second end 200 to re-weld the two armored tubes 1000.

[0113] In some embodiments, after the weld reinforcement inspection is qualified, the weld is subjected to visual inspection, penetrant testing, and radiographic testing. After the weld quality is qualified under visual inspection, penetrant testing, and radiographic testing, vacuum leak detection is performed.

[0114] It should be noted that the testing standards for vacuum leak detection are well-known in the industry and will not be elaborated here.

[0115] Once the vacuum leak test is passed, the weld between the 1000 armored tubes is truly completed, facilitating subsequent production processes.

[0116] In some embodiments, combined with Figure 2 and Figure 7 As shown, the support fixture 1100 includes a support plate 1110 and multiple support components 1120. The multiple support components 1120 are spaced apart on the support plate 1110 along a first direction, and each armored tube 1000 is simultaneously mounted on at least two support components 1120. This allows at least two support components 1120 to work together to support the armored tube 1000, ensuring the positional stability of the armored tube 1000 and reducing the difficulty of mounting the armored tube 1000 on the support components 1120.

[0117] The multiple support components 1120 are spaced apart on the support plate 1110 along the first direction, which can effectively support and fix the multiple support components 1120 and ensure the positional stability of the multiple support components 1120.

[0118] It should be noted that the phrase "each armor tube 1000 is simultaneously mounted on at least two support components 1120" means that it is not limited to mounting each armor tube 1000 on two support components 1120 at the same time. Each armor tube 1000 can also be mounted on three, four or more support components 1120.

[0119] In specific examples, combined Figure 2 and Figure 7As shown, the support fixture 1100 includes four support components 1120. Each armored tube 1000 is simultaneously mounted on two support components 1120 to achieve stable support of the armored tube 1000 using the support components 1120, thereby ensuring the positional reliability of the armored tube 1000.

[0120] It should also be noted that the multiple qualified support components 1120 are assembled on the support plate 1110, and the height of the multiple support components 1120 is adjusted so that the height of the armored tubes 1000 to be welded is consistent on the support fixture 1100. During the adjustment of the multiple support components 1120, a laser tracker is used to ensure high alignment accuracy of the multiple support components 1120, and to ensure that the surfaces to be welded between the two armored tubes 1000 are relatively flush, which facilitates the welding quality of the armored tubes 1000.

[0121] In some embodiments, combined with Figure 2 , Figure 7 and Figure 8 As shown, the support assembly 1120 includes a support block 1121, a pressure block 1122, and a fastener 1123. The pressure block 1122 is detachably connected to the top of the support block 1121 via the fastener 1123. The support block 1121 has a first groove 1124 on the side facing the pressure block 1122, and the pressure block 1122 has a second groove 1125 on the side facing the support block 1121, which is directly opposite the first groove 1124. The first groove 1124 and the second groove 1125 cooperate to form an assembly hole 1130. The armor tube 1000 passes through the assembly hole 1130, and the diameter of the assembly hole 1130 is smaller than the outer diameter of the armor tube 1000. The pressure block 1122 is detachably connected to the top of the support block 1121 by fastener 1123. Fastener 1123 can reduce the difficulty of installing and disassembling the pressure block 1122 and the support block 1121, so as to facilitate the subsequent assembly of the armor tube 1000 onto the support assembly 1120.

[0122] Meanwhile, by setting the first groove 1124 and the second groove 1125 facing each other, the first groove 1124 and the second groove 1125 cooperate to form the assembly hole 1130, and the diameter of the assembly hole 1130 is set to be smaller than the outer diameter of the armor tube 1000. In this way, during the welding process of the two armor tubes 1000 to be welded, the pressure block 1122 can be used to press the armor tube 1000 onto the support block 1121, so as to achieve precise positioning and centering of the two armor tubes 1000 to be welded, thereby avoiding the tube openings of the two armor tubes 1000 to be welded to close or open during the welding process, thus ensuring that the weld layer thickness between the two armor tubes 1000 to be welded is consistent and the forming is beautiful; the cooperation of the first groove 1124 and the second groove 1125 can reduce the forming difficulty of the assembly hole 1130.

[0123] In a specific example, fastener 1123 is formed as a bolt, screw, etc.

[0124] In some embodiments, combined with Figure 2 , Figure 7 and Figure 8 As shown, the pressure block 1122 has multiple first mounting holes 1126, and the support block 1121 has multiple second mounting holes 1127. At least a portion of the multiple first mounting holes 1126 is aligned with the multiple second mounting holes 1127. Fasteners 1123 pass through the first mounting holes 1126 and the second mounting holes 1127. This allows the pressure block 1122 to be detachably connected to the top of the support block 1121. Through the cooperation of the fasteners 1123, the first mounting holes 1126, and the second mounting holes 1127, the difficulty of disassembling the pressure block 1122 and the support block 1121 can be further reduced, and the connection reliability of the pressure block 1122 and the support block 1121 can be ensured, facilitating the fixing of the armor tube 1000 to the support assembly 1120.

[0125] In a specific example, in a support component 1120, the pressure block 1122 has four first mounting holes 1126, and the support block 1121 has four second mounting holes 1127. The four first mounting holes 1126 and the four second mounting holes 1127 correspond one-to-one. There are four fasteners 1123, which are sequentially inserted into the first mounting holes 1126 and the second mounting holes 1127. This achieves the purpose of pressing the pressure block 1122 tightly onto the support block 1121, thereby fixing the armored tube 1000 onto the support component 1120.

[0126] In some embodiments, the coaxiality of the mounting holes 1130 on two adjacent support components 1120 is less than or equal to 0.05 mm. This facilitates ensuring the positioning and alignment accuracy between the welding surfaces of the two armored tubes 1000, thereby ensuring that the pipe centers of the armored tubes 1000 coincide, avoiding misalignment or eccentricity between the two armored tubes 1000, and thus ensuring the welding effect between the two armored tubes 1000.

[0127] In some embodiments, combined with Figures 1-8 As shown, placing the two armored tubes 1000 to be welded on the support fixture 1100 includes the following steps:

[0128] S11. Place the armor tube 1000 on the support block 1121, and place a radial portion of the armor tube 1000 in the first groove 1124.

[0129] The above steps enable the armored tube 1000 to be initially positioned and installed on the support block 1121, facilitating subsequent installation steps.

[0130] S12. Assemble the pressure block 1122 on the top of the support block 1121, and place the other radial part of the armor tube 1000 in the second groove 1125.

[0131] The above steps enable the armored tube 1000 to be installed between the support block 1121 and the pressure block 1122, facilitating subsequent installation steps.

[0132] S13. Use fastener 1123 to pre-fix the pressure block 1122.

[0133] In the above steps, the armor tube 1000 is initially fixed between the support block 1121 and the pressure block 1122 to prevent the armor tube 1000 from sliding out of the assembly hole 1130.

[0134] In some embodiments, the pressure block 1122 may be pre-fixed by slightly tightening the fastener 1123.

[0135] S14, Axial moving armored tube 1000.

[0136] In the above steps, the two armored tubes 1000 are adjusted to ensure that they are aligned and to avoid misalignment. The distance between the surfaces to be welded between the two armored tubes 1000 must meet the welding technical requirements.

[0137] It should be noted that the smaller the distance between the welding surfaces of the two armored tubes (1000mm), the better.

[0138] S15. Use fasteners 1123 to fix the pressure block 1122 to the support block 1121.

[0139] In the above steps, after the welding surfaces between the two armored tubes 1000 are axially moved to a suitable welding distance, the fasteners 1123 are tightened to press the pressure block 1122 onto the support block 1121, thereby fixing the two armored tubes 1000.

[0140] In some embodiments, the sealing element is an aluminum plate, which is disposed at the first end 100 and bonded to the armored tube 1000. The aluminum plate is provided with multiple vent holes. This is to ensure that the internal and external pressures of the armored tube 1000 are basically balanced. That is, during welding, a slight positive pressure is maintained inside the armored tube 1000, and the multiple vent holes provide balanced pressure relief, thereby preventing excessive pressure inside the armored tube 1000.

[0141] Meanwhile, multiple vent holes serve as venting and pressure relief channels. When protective gas is introduced, the original air inside the armored tube 1000 can be slowly discharged through the vent holes, which facilitates the complete replacement of the air inside the armored tube 1000. This ensures that the back of the weld is in a gas-protected environment throughout the welding process, which is beneficial to improving the welding quality of the armored tube 1000.

[0142] In addition, the sealing component is made of aluminum plate. The melting point of aluminum is much lower than that of stainless steel. After welding and heating, it will not weld and stick to the armor tube 1000. Moreover, after the two armor tubes 1000 are welded, they can be easily removed, which can avoid damage to the first end 100.

[0143] In the specific example, the size of multiple vent holes is φ1mm.

[0144] In some embodiments, such as Figure 3 As shown, the back gas-insulating fixture 1200 includes a gas supply pipe 1220 and a rubber component 1230. The gas supply pipe 1220 is connected to the gas outlet pipe 1210 and is used to supply gas towards the gas outlet pipe 1210. The rubber component 1230 is fixedly connected to both axial ends of the gas outlet pipe 1210 and is adapted to have an interference fit with the inner circumferential wall of the armored pipe 1000. By connecting the gas supply pipe 1220 to the gas outlet pipe 1210, the gas supply pipe 1220 can effectively support the gas outlet pipe 1210, and the difficulty of supplying gas towards the gas outlet pipe 1210 from external gas source equipment can be reduced. Furthermore, the gas supply pipe 1220 has a certain length, which also reduces the difficulty of extending the gas supply pipe 1220 into the back of the weld.

[0145] Furthermore, by setting the rubber component 1230, not only can the two ends of the gas outlet pipe 1210 be fixed using the rubber component 1230, reducing the installation difficulty of the gas outlet pipe 1210, but also, by interfering with the inner circumferential wall of the armored tube 1000 of the rubber component 1230, it can be ensured that when the gas outlet pipe 1210 delivers protective gas during the welding process, the gas can be relatively sealed at the back of the weld. This achieves the protection of the back of the weld by gas, which is conducive to the formation of a good weld. In addition, the rubber component 1230 has a certain degree of elasticity, which can reduce the difficulty of pulling out the back gas protection fixture 1200 after the weld has cooled to room temperature.

[0146] In a specific example, the rubber component 1230 is formed as a rubber ring or rubber band.

[0147] In some embodiments, such as Figure 3 As shown, the back gas-insulating fixture 1200 also includes a fixing member 1240, which is used to fix the rubber part 1230. The fixing member 1240 can reduce the difficulty of fixing the rubber part 1230, thereby making it easier to ensure the reliability of the connection between the rubber part 1230 and the air outlet pipe 1210.

[0148] In a specific example, the fastener 1240 is formed as a nut and a washer, with the washer positioned between the rubber part 1230 and the nut to prevent the nut from directly squeezing and damaging the rubber part 1230, thereby ensuring the working effectiveness of the rubber part 1230.

[0149] In some embodiments, such as Figure 3 As shown, the vent pipe 1210 is provided with multiple vent ports 1211, which are arranged sequentially at intervals along the circumference and axial direction of the vent pipe 1210. The combination of multiple vent ports 1211 can increase the speed of gas discharge from the vent pipe 1210 and reduce the difficulty of gas discharge from the vent pipe 1210.

[0150] Meanwhile, by arranging multiple air outlets 1211 in a sequential and spaced manner along the circumference and axial direction of the air outlet pipe 1210, the air outlet pipe 1210 can be uniformly vented in the circumference and axial direction, avoiding residual dead corners, so that the back side of the weld is fully covered by gas.

[0151] In some embodiments, the diameter of the vent 1211 is 1mm to 2mm. When the diameter of the vent 1211 is too large, it is easy to cause strong airflow to impact the root of the weld, resulting in problems such as weld depression and poor weld formation; when the diameter of the vent 1211 is too small, the air output of the vent pipe 1210 is small, which is not conducive to protecting the back side of the weld.

[0152] In summary, this application sets the diameter of the vent 1211 to 1mm~2mm, which can not only avoid strong airflow impacting the root of the weld, thereby avoiding weld depression and poor weld formation, but also ensure the air output of the vent pipe 1210, achieving effective protection of the back side of the weld.

[0153] Specifically, the diameter of the air outlet 1211 is 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2mm, etc.

[0154] In some embodiments, the minimum distance between two adjacent air outlets 1211 in the axial direction of the air outlet pipe 1210 is 4mm to 6mm. When the minimum distance between two adjacent air outlets 1211 is too large, the uniformity of air outlet of the air outlet pipe 1210 is poor, and the protection effect on the back side of the weld is low; when the minimum distance between two adjacent air outlets 1211 is too small, the air outlets 1211 are difficult to process, and the structural strength of the air outlet pipe 1210 is also low.

[0155] In summary, in the axial direction of the vent pipe 1210, this application sets the minimum distance between two adjacent vent ports 1211 to 4mm~6mm, which not only ensures the uniformity of venting of the vent pipe 1210 and effectively protects the back side of the weld, but also reduces the processing difficulty of the vent ports 1211 and ensures the structural strength of the vent pipe 1210.

[0156] Specifically, in the axial direction of the air outlet pipe 1210, the minimum distance between two adjacent air outlets 1211 is 4mm, 4.1mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, 5.5mm, 5.6mm, 5.7mm, 5.8mm, 5.9mm, or 6mm, etc.

[0157] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0158] Other components of the welding method for the superconducting cable armor tube 1000 according to embodiments of the present invention, such as the specific structures of the sealing component and the fixing component 1240, are known to those skilled in the art and will not be described in detail here.

[0159] In the description of this specification, references to terms such as "embodiment," "example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0160] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A welding method for a superconducting cable armor tube, characterized in that, The welding method is based on a welding fixture, which includes a support fixture (1100) and a back gas shielding fixture (1200). The support fixture (1100) is used to support the armored tube to be welded, and the back gas shielding fixture (1200) includes a gas outlet pipe (1210) for supplying shielding gas to the back side of the weld during the welding process. The welding method includes the following steps: The two armored tubes to be welded are placed on the support fixture (1100), and the welding surfaces of the two armored tubes are arranged opposite each other along the first direction. One end of one of the armored tubes facing away from the surface to be welded is defined as the first end (100), and the other end of the armored tube facing away from the surface to be welded is defined as the second end (200). A sealing element is provided on the first end (100) to seal the first end (100). At least a portion of the back gas-insulating fixture (1200) is inserted into the armor tube through the second end (200), and the vent pipe (1210) is positioned facing the welding surfaces of the two armor tubes. Gas is delivered toward the surface to be welded through the back gas-insulating fixture (1200); The surface to be welded is divided into a base layer and a cover layer, and the base layer and the cover layer are equally divided into multiple sectors (300) arranged sequentially along their circumference. The multiple sectors (300) of the bottom layer are sequentially welded using a pulse welding process; The cover layer is sequentially welded using a non-pulse welding process; During the sequential welding of multiple sectors (300) of the base layer and the top layer, the welding current is reduced by 1A to 3A after each sector (300) is welded.

2. The welding method for the superconducting cable armor tube according to claim 1, characterized in that, The welding start points for both the base layer and the top layer are set at the six o'clock position on the surface to be welded, and the two armored tubes are welded in a counterclockwise direction.

3. The welding method for the superconducting cable armor tube according to claim 1, characterized in that, The root layer is divided into six sectors (300) arranged sequentially along its circumference. When the six sectors (300) of the root layer are welded sequentially using a pulse welding process, the welding currents of the six sectors (300) are 33.5A, 31.5A, 28.5A, 27.5A, 25.4A and 23.6A respectively. The welding time of each sector (300) is 4.87s, the welding speed is 2.05mm / s, the high pulse time is 0.2s, the low pulse time is 0.2s, and the shielding gas for welding is argon gas with a flow rate of 15L / min. The cover layer is divided into six sectors (300) arranged sequentially along its circumference. When the six sectors (300) of the cover layer are welded sequentially using a non-pulse welding process, the welding currents of the six sectors (300) are 22A, 21A, 20A, 19A, 18A and 17A respectively. The welding time of each sector (300) is 4.35s, the welding speed is 2.3mm / s, and the shielding gas for welding is a second argon gas with a flow rate of 15L / min.

4. The welding method for the superconducting cable armor tube according to claim 1, characterized in that, The back gas-insulating fixture (1200) is used to deliver a third argon gas toward the surface to be welded, and the flow rate of the third argon gas is 5L / min.

5. The welding method for the superconducting cable armor tube according to claim 1, characterized in that, Before dividing the surface to be welded into two layers, a base layer and a cover layer, and before equally dividing the base layer and the cover layer into multiple sectors (300) arranged sequentially along their circumference, the method further includes the following steps: The two armored tubes were spot-welded together using an instant spot welding process.

6. The welding method for the superconducting cable armor tube according to claim 1, characterized in that, The welding fixture also includes a weld inspection gauge (1300), which is used to inspect the back reinforcement of the weld after welding. The welding method also includes the following steps: After the weld has cooled to room temperature, close and remove the back gas-insulating fixture (1200). The weld reinforcement height on the back side is inspected using the weld inspection gauge (1300) to determine whether the weld meets the weld reinforcement quality requirements. If yes, the welding is complete; if no, the weld is cut off, and at least a portion of the back gas-insulating tool (1200) is inserted into the armored tube through the second end (200) to re-weld the two armored tubes.

7. The welding method for the superconducting cable armor tube according to claim 1, characterized in that, The support fixture (1100) includes a support plate (1110) and a plurality of support components (1120). The plurality of support components (1120) are spaced apart on the support plate (1110) along the first direction, and each armor tube is simultaneously disposed on at least two of the support components (1120).

8. The welding method for the superconducting cable armor tube according to claim 7, characterized in that, The support assembly (1120) includes a support block (1121), a pressure block (1122), and a fastener (1123). The pressure block (1122) is detachably connected to the top of the support block (1121) via the fastener (1123). The support block (1121) has a first groove (1124) on the side facing the pressure block (1122), and the pressure block (1122) has a second groove (1125) facing the first groove (1124) on the side facing the support block (1121). The first groove (1124) and the second groove (1125) cooperate to form an assembly hole (1130). The armor tube passes through the assembly hole (1130), and the diameter of the assembly hole (1130) is smaller than the outer diameter of the armor tube.

9. The welding method for the superconducting cable armor tube according to claim 8, characterized in that, The coaxiality of the mounting holes (1130) on two adjacent support components (1120) is less than or equal to 0.05 mm.

10. The welding method for the superconducting cable armor tube according to claim 8, characterized in that, The step of placing the two armored tubes to be welded on the support fixture (1100) includes the following steps: The armor tube is placed on the support block (1121), and a radial portion of the armor tube is placed in the first groove (1124); The pressure block (1122) is assembled on the top of the support block (1121), and the other radial portion of the armor tube is disposed in the second groove (1125); The pressure block (1122) is pre-fixed using the fastener (1123); The armor tube is moved axially; The pressure block (1122) is fixedly connected to the support block (1121) using the fastener (1123).

11. The welding method for the superconducting cable armor tube according to claim 1, characterized in that, The sealing component is an aluminum plate, which is located at the first end (100) and bonded to the armored tube. The aluminum plate has multiple vent holes.

12. The welding method for the superconducting cable armor tube according to any one of claims 1-11, characterized in that, The back gas-insulating fixture (1200) includes a gas supply pipe (1220) and a rubber component (1230). The gas supply pipe (1220) is connected to the gas outlet pipe (1210) and is used to supply gas toward the gas outlet pipe (1210). The rubber component (1230) is fixedly connected to both ends of the axial direction of the gas outlet pipe (1210) and is adapted to be interference-fitted with the inner circumferential wall of the armored tube.

13. The welding method for the superconducting cable armor tube according to claim 12, characterized in that, The air outlet pipe (1210) is provided with a plurality of air outlets (1211), and the plurality of air outlets (1211) are arranged sequentially at intervals along the circumference and axial direction of the air outlet pipe (1210); Wherein, the diameter of the air outlet (1211) is 1mm~2mm; and / or, in the axial direction of the air outlet pipe (1210), the minimum distance between two adjacent air outlets (1211) is 4mm~6mm.

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