Welding tool and welding method for inner conductor and outer conductor of radio frequency superconducting cavity

Abstract

A welding tool for an inner conductor and an outer conductor of a radio frequency superconducting cavity comprises an outer welding seam auxiliary tool and an inner welding seam auxiliary tool. The outer welding seam auxiliary tool comprises a limiting pull rod, a first limiting plate and a second limiting plate, the two end parts of the limiting pull rod penetrate through the first limiting plate and the second limiting plate respectively, so that the outer conductor is clamped and fixed; the inner welding seam auxiliary tool comprises a first pressing head and a second pressing head which are arranged oppositely. The first pressure head and the second pressure head are both provided with exhaust holes, an arc-shaped structure matched with the outer conductor is formed on one side, facing the first pressure head, of the second pressure head, and a fixing rod for assembling the inner conductor and the outer conductor into a whole is installed between the first pressure head and the second pressure head. The invention further provides a welding method for the inner conductor and the outer conductor of the radio frequency superconducting cavity. The welding problem of the special structure of the outer conductor is solved, and the welding quality is guaranteed; the thermal deformation of the elliptical curved surface structure with a specific size when the elliptical curved surface structure is welded with the inner conductor is reduced, and the welding precision is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of radio frequency superconducting cavities, and in particular to a welding tool and a welding method for an inner conductor and an outer conductor of a radio frequency superconducting cavity. Background Art

[0002] Spoke-type superconducting cavities are usually composed of end caps, inner conductors, outer conductors, coupling tubes and flanges. The RF superconducting cavity with a specific resonant frequency that meets the design requirements is manufactured by vacuum electron beam welding. Compared with the original single-Spoke RF superconducting cavity, the 648MHzβ=0.4 single-Spoke RF superconducting cavity has basically the same structure, but there is a special physical design structure at the outer conductor. Mainly at the interface where the outer conductor and the inner conductor are welded, there is an elliptical surface structure with a specific size on the outer conductor. According to the design requirements, the weld between the inner conductor and the outer conductor should not form welding defects such as undercuts and holes after welding. Because the electric field at the welding point is relatively strong during the operation of the RF superconducting cavity, the welding defects will cause tip discharge and generate free electrons. The free electrons enter the acceleration gap and affect the beam quality. At the same time, according to the design requirements, the internal weld should not have an R angle after welding.

[0003] The outer conductor of the 648MHz single-Spoke040 type RF superconducting cavity adopts the overall processing method of the outer conductor of the general single-Spoke type RF superconducting cavity. The elliptical surface structure of a specific size in the outer conductor cannot be realized during processing; according to the design requirements of the 648MHz single-Spoke040 type RF superconducting cavity, the weld formed after the inner conductor and the outer conductor are assembled, and after welding, the internal weld cannot have R angle (chamfer or fillet), and the weld between the inner conductor and the outer conductor cannot form welding defects such as undercut and holes after welding. Because the electric field at the welding point is relatively strong during the operation of the RF superconducting cavity, the welding defects will cause tip discharge, generate free electrons, and the free electrons enter the acceleration gap, affecting the beam quality. Therefore, the welding method of welding on one side and forming on two sides cannot be adopted. One weld can only be welded by welding on the inside and outside. In addition, due to the cylindrical structure of the outer conductor, the shielding of the components makes it impossible for the electron beam welder to complete the welding of the inside and outside. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned technologies, it is necessary to provide a welding tool for the conductor inside and outside the radio frequency superconducting cavity.

[0005] A welding tool for a radio frequency superconducting cavity inner conductor and an outer conductor, comprising an outer welding seam auxiliary tool and an inner welding seam auxiliary tool; The external weld auxiliary tooling includes a first limit plate, a second limit plate, and a limit pull rod; the first limit plate and the second limit plate are arranged opposite to each other, and the two ends of the limit pull rod respectively penetrate the first limit plate and the second limit plate and then fix the first limit plate and the second limit plate, so that the first limit plate and the second limit plate can clamp the external conductor to limit the axial displacement and radial displacement of the external conductor; The inner weld auxiliary tooling includes a first pressing head and a second pressing head for pressing the outer conductor at the two ends of the inner conductor; the first pressing head and the second pressing head are arranged opposite to each other, and exhaust holes are provided on the first pressing head and the second pressing head; the second pressing head forms an arc structure adapted to the outer conductor on the side facing the first pressing head; a fixing rod is installed between the first pressing head and the second pressing head, so that the first pressing head and the second pressing head assemble the inner conductor and the outer conductor into one.

[0006] Preferably, a limiting column matching the inner diameter of the outer conductor is provided on the surface of the first limiting plate facing the second limiting plate and on the surface of the second limiting plate facing the first limiting plate.

[0007] Preferably, a limiting groove concentric with the limiting column is formed on the surface of the first limiting plate facing the second limiting plate and on the surface of the second limiting plate facing the first limiting plate, and the inner diameter of the limiting groove is the same as the diameter of the limiting column.

[0008] Preferably, the first limit plate and the second limit plate are respectively provided with fixing through holes, and a fastening rod which can be inserted into the fixing through holes is installed between the first limit plate and the second limit plate to realize the assembly of the first limit plate and the second limit plate.

[0009] Preferably, a connection sleeve for connecting to an electron beam welder is provided on the surface of the first limit plate away from the second limit plate; and a connection head for connecting to an electron beam welder is installed on the side of the first pressure head away from the second pressure head.

[0010] A method for welding a radio frequency superconducting cavity conductor and an outer conductor, using the above-mentioned radio frequency superconducting cavity conductor and outer conductor welding tool for welding, comprising the following steps: Step S1: Use an external weld auxiliary tooling to assemble the inner conductor and the outer conductor into one piece, so that the two outer conductors are assembled at the two ends of the inner conductor, and load them into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the outer weld of the outer conductor and the inner conductor; after the welding is completed, remove the external weld auxiliary tooling; Step S2: using the inner weld auxiliary tooling to reassemble the outer conductor and the inner conductor after the outer weld is welded, and then loading them into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, the inner weld of the outer conductor and the inner conductor is welded using the corresponding welding process; after the welding is completed, the inner weld auxiliary tooling is disassembled; Step S3: Use the outer weld auxiliary tooling to reassemble the remaining outer conductor and the workpiece welded in step S2 into one piece, so that the remaining outer conductor and the welded outer conductor form a ring structure, and load it into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the welds between adjacent outer conductors; after the welding is completed, remove the outer weld auxiliary tooling, and the inner conductor and the outer conductor can be welded as a whole.

[0011] Preferably, in step S1, the welding of the outer conductor and the outer weld of the inner conductor is carried out in the following manner: S11: first assemble the first limit plate and the connecting sleeve and fasten them with screws to form a composite tooling; S12: After the superconducting cavity conductor and the two outer conductors are assembled and installed together, the whole is assembled in coordination with the composite tooling in step S11, so that the two outer conductors are inserted into the limiting grooves of the first limiting plate, and the inner surface is closely attached to the limiting column surface of the first limiting plate; S13: Install the limit pull rod in the center hole of the inner conductor and the center hole of the first limit plate, and assemble them in place; S14: Install the second limiting plate, so that the limiting pull rod passes through its center hole, and the two outer conductors are clamped in the limiting groove of the second limiting plate, with the inner surface tightly fitting on the surface of the limiting column of the second limiting plate, and at the same time, the fixing through holes on the second limiting plate and the first limiting plate are opposite to each other; S15: After confirming that the two outer conductors are clamped in the limiting grooves of the first limiting plate and the second limiting plate, and the inner surfaces are tightly attached to the limiting column surfaces of the first limiting plate and the second limiting plate, a fastening rod is installed in the fixed through holes on the first limiting plate and the second limiting plate, and both ends are fastened with nuts, and nuts are installed at both ends of the limiting pull rod for fastening; S16: Place the weldment and the fastener of the tooling horizontally into the welding chamber of the electron beam welder, and fasten the connecting sleeve into the chuck of the welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the external welds of the outer conductor and the inner conductor; after the welding is completed, remove the auxiliary tooling of the external weld.

[0012] Preferably, in step S16, the following method is used when welding the outer weld of the outer conductor and the inner conductor: After the vacuum is exhausted to meet the process requirements, the first external weld formed by the outer conductor and the inner conductor is spot welded by spot welding; After the spot welding is completed, the welding workpiece and the tooling are rotated 180° by the welding machine chuck, and the second outer conductor and the outer weld of the inner conductor are spot welded first, and then the corresponding welding process is used to formally weld this weld; After welding is completed, the weldment and the tooling are rotated 180° by the welding machine chuck, and the first outer conductor and the outer weld of the inner conductor are formally welded using the corresponding welding process.

[0013] Preferably, in step S2, the welding of the outer conductor and the inner weld of the inner conductor is carried out in the following manner: S21: Assemble the first pressing head and the connecting sleeve together and fasten them into one piece with a fixing rod to form a composite tool; S22: Fitting the outer surface of the first outer conductor of the welded body with the first pressing head in the composite tooling together; inserting the second pressing head into the end of the inner conductor located at the second outer conductor, and aligning the screw hole on the second pressing head with the screw hole on the first pressing head; then inserting a fixing rod into the screw hole and tightening it with a nut to make the weldment and the welding tooling integrated; S23: Insert the connecting sleeve into the chuck in the welding chamber of the electron beam welder. The elevation angle of the welding machine chuck is 42°. After the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the internal welds of the outer conductor and the inner conductor. After the welding is completed, remove the internal weld auxiliary tooling.

[0014] Preferably, in step S23, the following method is used when welding the inner weld of the outer conductor and the inner conductor: After the vacuum is exhausted to meet the process requirements, the inner weld of the inner conductor and the first outer conductor is welded according to the welding process. After welding, the inner weld of the inner conductor and the first outer conductor is taken out of the furnace after reaching the furnace conditions. The inner weld of the inner conductor and the first outer conductor is welded. After the weldment is rotated 180°, the end of the second outer conductor is matched with the first pressing head, and the above steps are repeated to complete the welding of the inner seam between the inner conductor and the second outer conductor.

[0015] Compared with the prior art, the welding tooling and welding method for the RF superconducting cavity conductor and the outer conductor provided by the present invention divide the outer conductor into a plurality of independent parts, wherein the parts to be welded in combination with the inner conductor have an elliptical surface structure of a specific size. The designed outer weld auxiliary tooling and inner weld auxiliary tooling are used to fix and clamp the parts. The inner conductor is first welded to two of the outer conductor parts with an elliptical surface structure of a specific size to form a welded body. Then, the welding tooling is used to assemble the welded body with other parts to form a complete outer conductor. The present invention solves the welding problem of the special structure of the outer conductor, realizes the purpose of coinciding the central axis of the inner conductor with the arc axis of the two pieces of the outer conductor, and ensures the welding quality; reduces the thermal deformation of the elliptical surface structure with a specific size when welding with the inner conductor; forms a method for electron beam welding of 648MHz single-Spoke type RF superconducting cavity conductor and outer conductor assembly, and ensures welding accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of the external weld auxiliary tooling of the present invention.

[0018] Figure 2 For the present invention Figure 1 Schematic diagram of the structure from another angle.

[0019] Figure 3 It is a schematic diagram of the structure of the external welding seam auxiliary tooling of the present invention when clamping the outer conductor and the inner conductor.

[0020] Figure 4 It is a structural schematic diagram of the internal weld auxiliary tooling of the present invention.

[0021] Figure 5 For the present invention Figure 4 Schematic diagram of the structure from another angle.

[0022] Figure 6 It is a schematic diagram of the structure of the inner welding seam auxiliary tooling of the present invention when clamping the outer conductor and the inner conductor.

[0023] Figure 7 It is a schematic diagram of welding an external weld according to the present invention.

[0024] Figure 8 It is a schematic diagram of welding an internal weld according to the present invention.

[0025] Fig. 9 It is a schematic structural diagram of the first limiting plate of the present invention.

[0026] In the figure: a first limiting plate 01, a limiting column 11, a limiting groove 12, a fixing through hole 13, a second limiting plate 02, a limiting pull rod 03, a first pressing head 04, a second pressing head 05, an exhaust hole 06, a fixing rod 07, a fastening rod 08, a connecting sleeve 09, a connector 10, a first outer conductor 20, a second outer conductor 30, an inner conductor 40, and a screw hole 50. DETAILED DESCRIPTION

[0027] 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.

[0028] In the description of the present invention, it should be understood that the terms "upper", "middle", "outer", "inner", "lower" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0029] Please see Figures 1 to 6 , the present invention provides a welding tool for a radio frequency superconducting cavity conductor and an outer conductor, including an outer welding seam auxiliary tool and an inner welding seam auxiliary tool; Among them, the external welding seam auxiliary tooling includes a first limit plate 01, a second limit plate 02, and a limit rod 03; the first limit plate 01 and the second limit plate 02 are arranged opposite to each other, and the two ends of the limit rod 03 respectively penetrate the first limit plate 01 and the second limit plate 02 and then fix the first limit plate 01 and the second limit plate 02, so that the first limit plate 01 and the second limit plate 02 can clamp the outer conductor to limit the axial displacement and radial displacement of the outer conductor. The two ends of the limit rod 03 are correspondingly provided with top holes to facilitate the insertion of the welding machine top. Among them, the fastening rod 08 can adopt a screw with threads at both ends to facilitate the adaptation and fastening of the nut.

[0030] Among them, the inner weld auxiliary tooling includes a first pressing head 04 and a second pressing head 05 for pressing the outer conductor at the two ends of the inner conductor 40; the first pressing head 04 and the second pressing head 05 are arranged opposite to each other, and exhaust holes 06 are provided on the first pressing head 04 and the second pressing head 05, through which the smoke and air generated during welding can be discharged, and part of the welding heat can also be taken away. The second pressing head 05 forms an arc structure adapted to the outer conductor on the side facing the first pressing head 04, so that when the weldment and the tooling are assembled, the deformation of the elliptical surface structure of a specific size is avoided, and the thermal deformation caused when welding the inner weld can be prevented. A fixing rod 07 is installed between the first pressing head 04 and the second pressing head 05, so that the first pressing head 04 and the second pressing head 05 assemble the inner conductor 40 and the outer conductor into one. Screw holes 50 for the fixing rod 07 to pass through are provided on the first pressing head 04 and the second pressing head 05, and threads are formed at both ends of the fixing rod 07 to facilitate the fitting and tightening of the nut.

[0031] Please see Fig. 9 In one embodiment, a limiting column 11 matching the inner diameter of the outer conductor is provided on the surface of the first limiting plate 01 facing the second limiting plate 02, and on the surface of the second limiting plate 02 facing the first limiting plate 01. The limiting column 11 limits the inner diameter of the welded part and ensures the roundness of the welded part.

[0032] Of course, a central positioning hole is also provided in the middle of the first limiting plate 01 toward the second limiting plate 02, and the central positioning hole is used to insert the limiting pull rod 03. The center of the central positioning hole is concentric with the circle of the limiting column 11, and finally the coaxial accuracy of the center hole of the inner conductor 40 and the intermediate ring is ensured.

[0033] Specifically, a limiting groove 12 concentric with the limiting column 11 is provided on the surface of the first limiting plate 01 facing the second limiting plate 02, and on the surface of the second limiting plate 02 facing the first limiting plate 01, and the inner diameter of the limiting groove 12 is the same as the diameter of the limiting column 11. The limiting groove 12 is composed of the diameter difference of the inner and outer concentric circles and a certain depth, and is used to clamp and position the outer conductor so that the diameter of the weldment meets the design requirements of the outer conductor.

[0034] Specifically, the first limit plate 01 and the second limit plate 02 are provided with corresponding fixing through holes 13, and a fastening rod 08 that can be inserted into the fixing through holes 13 is installed between the first limit plate 01 and the second limit plate 02 to realize the assembly of the first limit plate 01 and the second limit plate 02. By fastening the fastening rod 08 with the nut, the weldment assembled between the first limit plate 01 and the second limit plate 02 can be firmly fixed to increase the welding accuracy.

[0035] In one embodiment, a connection sleeve 09 for connecting to an electron beam welder is provided on a surface of the first limit plate 01 away from the second limit plate 02. A connection head 10 for connecting to an electron beam welder is installed on a side of the first pressure head 04 away from the second pressure head 05.

[0036] In one embodiment, the present invention provides a method for welding a radio frequency superconducting cavity conductor and an outer conductor, which is welded using a radio frequency superconducting cavity conductor and an outer conductor welding tool, comprising the following steps: Step S1: Use the outer weld auxiliary tooling to assemble the inner conductor 40 and the outer conductor into one body, so that the two outer conductors are assembled at the two ends of the inner conductor 40, and are loaded into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the outer weld of the outer conductor and the inner conductor 40; after the welding is completed, remove the outer weld auxiliary tooling.

[0037] Step S2: Use the inner weld auxiliary tooling to reassemble the outer conductor and the inner conductor 40 after the outer weld is welded, and load them into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the inner weld of the outer conductor and the inner conductor 40; after the welding is completed, remove the inner weld auxiliary tooling.

[0038] Step S3: Use the outer weld auxiliary tooling to reassemble the remaining outer conductor and the workpiece welded in step S2 into one piece, so that the remaining outer conductor and the welded outer conductor form a ring structure, and load it into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the welds between adjacent outer conductors; after the welding is completed, remove the outer weld auxiliary tooling, and the inner conductor 40 and the outer conductor can be welded as a whole.

[0039] Please see Figure 7 Of course, to be more specific, in step S1, the welding of the outer weld of the outer conductor and the inner conductor 40 is carried out in the following manner: S11: First, assemble the first limiting plate 01 and the connecting sleeve 09 and fasten them with screws to form a composite tooling.

[0040] S12: After the superconducting cavity conductor 40 is assembled with the two outer conductors, the whole is installed in coordination with the composite tooling in step S11, so that the two outer conductors are inserted into the limiting groove 12 of the first limiting plate 01, and the inner surface is tightly fitted on the surface of the limiting column 11 of the first limiting plate 01; the purpose is to make the arc curvature of the first outer conductor 20 and the second outer conductor 30 after welding consistent with the design curvature of the outer conductor.

[0041] S13: Install the limiting pull rod 03 in the center hole of the inner conductor 40 and the center hole of the first limiting plate 01, and assemble them in place; to play a positioning and fixing role, the purpose is to make the center axis of the outer conductor coincide with the center axis of the inner conductor 40 to meet the process requirements.

[0042] S14: Install the second limiting plate 02 so that the limiting rod 03 passes through its center hole, and the two outer conductors are clamped in the limiting groove 12 of the second limiting plate 02, with the inner surface tightly fitting on the surface of the limiting column 11 of the second limiting plate 02, and at the same time, the fixing through holes 13 on the second limiting plate 02 and the first limiting plate 01 are opposite to each other.

[0043] S15: After confirming that the two outer conductors are clamped in the limiting grooves 12 of the first limiting plate 01 and the second limiting plate 02, and the inner surfaces are tightly fitted in the limiting columns 11 of the first limiting plate 01 and the second limiting plate 02, install the fastening rod 08 into the fixed through holes 13 on the first limiting plate 01 and the second limiting plate 02, and fasten the two ends with nuts. At the same time, nuts are installed at both ends of the limiting pull rod 03 for fastening. The purpose is to make the weldment and the welding tooling form a rigid whole to prevent the heat generated during electron beam welding from causing deformation of the weldment.

[0044] S16: The weldment and the fastener of the tooling are horizontally loaded into the welding chamber of the electron beam welder, and the connecting sleeve 09 is clamped into the welding machine chuck for fastening; after the vacuum is evacuated to meet the process requirements, the outer weld of the outer conductor and the inner conductor 40 is welded using the corresponding welding process; after the welding is completed, the outer weld auxiliary tooling is removed.

[0045] Please see Figure 8 Of course, to be more specific, in step S16, the following method is used when welding the outer conductor and the outer weld of the inner conductor 40: After the vacuum is exhausted to meet the process requirements, the first outer conductor 20 and the inner conductor 40 are spot welded to form an outer weld. After the spot welding is completed, the weldment and the tooling are rotated 180° by the welding machine chuck, and the second outer conductor 30 and the inner conductor 40 outer weld are first spot welded, and then the corresponding welding process is used to formally weld this weld; After the welding is completed, the welding workpiece and the tooling are rotated 180 degrees by the welding machine chuck, and the first outer conductor 20 and the inner conductor 40 are formally welded using the corresponding welding process.

[0046] Of course, to explain more specifically, in step S2, the welding of the outer conductor and the inner weld of the inner conductor 40 is carried out in the following manner: S21: Assemble the first pressing head 04 and the connecting sleeve together, and fasten them into one piece with the fixing rod 07 to form a composite tool.

[0047] S22: The outer surface of the first outer conductor 20 of the welded body with the outer weld completed is fitted together with the first ram 04 in the composite tooling; the second ram 05 is inserted into the end of the inner conductor 40 located at the second outer conductor 30, and the screw hole 50 on the second ram 05 is aligned with the screw hole 50 on the first ram 04; then the fixing rod 07 is installed in the screw hole 50 and fastened with a nut to make the weldment and the welding tooling become one; and the arc-shaped structural surface of the first ram 04 is exactly the same as the structure of the outer conductor, so as to protect the elliptical surface structure of a specific size from thermal deformation and ensure accuracy when the internal weld is formed when welding the inner conductor 40 with the first outer conductor 20 and the second outer conductor 30.

[0048] S23: Insert the connecting sleeve into the chuck in the welding chamber of the electron beam welder. The chuck of the welder has an elevation angle of 42°. The purpose of this elevation angle is to ensure that the welding electron beam generated by the electron beam welder can be unobstructed and continuously hit the internal weld bead when the chuck drives the weldment and the tooling to rotate 360 ​​degrees during welding, so as to ensure that the weld bead weld is continuous and closed after welding. After the vacuum is exhausted to meet the process requirements, the internal weld of the outer conductor and the inner conductor 40 is welded using the corresponding welding process; after welding, the internal weld auxiliary tooling is removed.

[0049] Of course, to explain more specifically, in step S23, the following method is used when welding the outer conductor and the inner weld of the inner conductor 40: After the vacuum is exhausted to meet the process requirements, the inner weld of the inner conductor 40 and the first outer conductor 20 are welded according to the welding process. After the welding is completed, the inner weld of the inner conductor 40 and the first outer conductor 20 is taken out of the furnace after the furnace conditions are met. The inner weld of the inner conductor 40 and the first outer conductor 20 is welded. After the weldment is rotated 180°, the end of the second outer conductor 30 is matched with the first pressing head 04, and the above steps are repeated to complete the welding of the inner conductor 40 and the internal weld of the second outer conductor 30.

[0050] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A welding tool for a radio frequency superconducting cavity conductor and an outer conductor, characterized in that: Including external welding auxiliary tooling and internal welding auxiliary tooling; The external weld auxiliary tooling includes a first limit plate, a second limit plate, and a limit pull rod; the first limit plate and the second limit plate are arranged opposite to each other, and the two ends of the limit pull rod respectively penetrate the first limit plate and the second limit plate and then fix the first limit plate and the second limit plate, so that the first limit plate and the second limit plate can clamp the external conductor to limit the axial displacement and radial displacement of the external conductor; The inner weld auxiliary tooling includes a first pressing head and a second pressing head for pressing the outer conductor at the two ends of the inner conductor; the first pressing head and the second pressing head are arranged opposite to each other, and exhaust holes are provided on the first pressing head and the second pressing head; the second pressing head forms an arc structure adapted to the outer conductor on the side facing the first pressing head; a fixing rod is installed between the first pressing head and the second pressing head, so that the first pressing head and the second pressing head assemble the inner conductor and the outer conductor into one.

2. The welding tool for the radio frequency superconducting cavity conductor and the outer conductor according to claim 1 is characterized in that: The surface of the first limiting plate facing the second limiting plate and the surface of the second limiting plate facing the first limiting plate are both provided with limiting columns that match the inner diameter of the outer conductor.

3. The welding tool for the radio frequency superconducting cavity conductor and the outer conductor according to claim 2 is characterized in that: A limiting groove concentric with the limiting column is provided on the surface of the first limiting plate facing the second limiting plate and on the surface of the second limiting plate facing the first limiting plate. The inner diameter of the limiting groove is the same as the diameter of the limiting column.

4. The welding tool for the radio frequency superconducting cavity conductor and the outer conductor according to claim 1, characterized in that: The first limiting plate and the second limiting plate are both provided with fixing through holes correspondingly, and a fastening rod which can be inserted into the fixing through holes is installed between the first limiting plate and the second limiting plate to realize the assembly of the first limiting plate and the second limiting plate.

5. The welding tool for the radio frequency superconducting cavity conductor and the outer conductor according to claim 1, characterized in that: A connection sleeve for connecting to an electron beam welder is arranged on the surface of the first limit plate on one side away from the second limit plate; a connection head for connecting to an electron beam welder is installed on the side of the first pressure head away from the second pressure head.

6. A method for welding a radio frequency superconducting cavity conductor and an outer conductor, using the radio frequency superconducting cavity conductor and outer conductor welding tool as claimed in any one of claims 1 to 5 for welding, characterized in that: The following steps are included: Step S1: Use an external welding seam auxiliary tool to assemble the inner conductor and the outer conductor into one body, assemble the two outer conductors at the two ends of the inner conductor, and load them into the welding chamber of the electron beam welding machine; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the outer weld of the outer conductor and the inner conductor; After welding is completed, remove the external weld auxiliary tooling; Step S2: using the inner weld auxiliary tooling to reassemble the outer conductor and the inner conductor after the outer weld is welded, and then loading them into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, the inner weld of the outer conductor and the inner conductor is welded using the corresponding welding process; after the welding is completed, the inner weld auxiliary tooling is disassembled; Step S3: Use the outer weld auxiliary tooling to reassemble the remaining outer conductor and the workpiece welded in step S2 into one piece, so that the remaining outer conductor and the welded outer conductor form a ring structure, and load it into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the welds between adjacent outer conductors; after the welding is completed, remove the outer weld auxiliary tooling, and the inner conductor and the outer conductor can be welded as a whole.

7. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 6, characterized in that: In step S1, the outer conductor and the outer weld of the inner conductor are welded in the following manner: S11: first assemble the first limit plate and the connecting sleeve and fasten them with screws to form a composite tooling; S12: After the superconducting cavity conductor and the two outer conductors are assembled and installed together, the whole is assembled in coordination with the composite tooling in step S11, so that the two outer conductors are inserted into the limiting grooves of the first limiting plate, and the inner surface is closely attached to the limiting column surface of the first limiting plate; S13: Install the limit pull rod in the center hole of the inner conductor and the center hole of the first limit plate, and assemble them in place; S14: Install the second limiting plate, so that the limiting pull rod passes through its center hole, and the two outer conductors are clamped in the limiting groove of the second limiting plate, with the inner surface tightly fitting on the surface of the limiting column of the second limiting plate, and at the same time, the fixing through holes on the second limiting plate and the first limiting plate are opposite to each other; S15: After confirming that the two outer conductors are clamped in the limiting grooves of the first limiting plate and the second limiting plate, and the inner surfaces are tightly attached to the limiting column surfaces of the first limiting plate and the second limiting plate, a fastening rod is installed in the fixed through holes on the first limiting plate and the second limiting plate, and both ends are fastened with nuts, and nuts are installed at both ends of the limiting pull rod for fastening; S16: Place the weldment and the fastener of the tooling horizontally into the welding chamber of the electron beam welder, and fasten the connecting sleeve into the chuck of the welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the external welds of the outer conductor and the inner conductor; after the welding is completed, remove the auxiliary tooling of the external weld.

8. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 7, characterized in that: In step S16, the following method is used when welding the outer weld of the outer conductor and the inner conductor: After the vacuum is exhausted to meet the process requirements, the first external weld formed by the outer conductor and the inner conductor is spot welded by spot welding; After the spot welding is completed, the welding workpiece and the tooling are rotated 180° by the welding machine chuck, and the second outer conductor and the outer weld of the inner conductor are spot welded first, and then the corresponding welding process is used to formally weld this weld; After welding is completed, the weldment and the tooling are rotated 180° by the welding machine chuck, and the first outer conductor and the outer weld of the inner conductor are formally welded using the corresponding welding process.

9. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 6, characterized in that: In step S2, the welding of the outer conductor and the inner weld of the inner conductor is carried out in the following manner: S21: Assemble the first pressing head and the connecting sleeve together and fasten them into one piece with a fixing rod to form a composite tool; S22: Fitting the outer surface of the first outer conductor of the welded body with the first pressing head in the composite tooling together; inserting the second pressing head into the end of the inner conductor located at the second outer conductor, and aligning the screw hole on the second pressing head with the screw hole on the first pressing head; then inserting a fixing rod into the screw hole and tightening it with a nut to make the weldment and the welding tooling integrated; S23: Insert the connecting sleeve into the chuck in the welding chamber of the electron beam welder. The elevation angle of the welding machine chuck is 42°. After the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the internal welds of the outer conductor and the inner conductor. After the welding is completed, remove the internal weld auxiliary tooling.

10. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 9, characterized in that: In step S23, the following method is used when welding the inner weld of the outer conductor and the inner conductor: After the vacuum is exhausted to meet the process requirements, the inner weld of the inner conductor and the first outer conductor is welded according to the welding process. After welding, the inner weld of the inner conductor and the first outer conductor is taken out of the furnace after reaching the furnace conditions. The inner weld of the inner conductor and the first outer conductor is welded. After the weldment is rotated 180°, the end of the second outer conductor is matched with the first pressing head, and the above steps are repeated to complete the welding of the inner seam between the inner conductor and the second outer conductor.

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