A welding method for electron gun cathode heat shield assembly

Abstract

The present invention provides a method for welding a cathode heat shield assembly of an electron gun, wherein the cathode heat shield assembly includes a heat shield tube, a cathode assembly, and a heater assembly. The cathode assembly includes a cathode tube, a cathode cake, and a cathode support tube sleeved around the outer circumference and lower end of the cathode tube, wherein a heater passage hole is formed at the bottom of the cathode support tube. The welding method for the cathode heat shield assembly includes the following steps: a pressing step: applying pre-pressure to the cathode tube and the cathode support tube to compress the contact surfaces of the cathode tube and the cathode support tube to form a conductive path; a resistance welding step: applying power to the cathode tube and the cathode support tube to form a molten core at the connection between the cathode tube and the cathode support tube; and a power-off forging step: stopping power to the cathode tube and the cathode support tube and maintaining pressure between the cathode tube and the cathode support tube to allow the molten core to cool and crystallize. Through the above welding method, sufficient bonding force between the cathode tube and the cathode support tube is ensured, and the electron emission effect of the cathode is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic equipment, and specifically provides a welding method for a cathode heat shield assembly of an electron gun. Background Art

[0002] An electron gun is a device that generates, accelerates, and focuses a high-energy electron beam. It emits electrons with a specific energy, current, velocity, and angle. In an electron gun, the heater is typically a tungsten filament. When heated by electricity, a large number of thermal electrons are generated on the surface. Under the influence of the high-voltage electric field between the anode and cathode, these thermal electrons are accelerated toward the anode, acquiring high kinetic energy. The focusing electrode then focuses the electron beam.

[0003] The cathode tubes used in existing electron gun heat shield assemblies are mostly made of molybdenum metal, which is difficult to weld. Therefore, existing electron guns typically use platinum foil as a transition solder and laser weld the cathode tube to the cathode support tube. Specifically, the platinum foil is first laser welded to the cathode tube, and then the cathode tube with the platinum foil welded to the cathode support tube is welded, allowing the platinum foil to act as the solder. However, when the electron gun is operating, the heater generates a large amount of heat, and the platinum foil used for welding is prone to evaporation at high temperatures, which can easily contaminate the cathode of the electron gun and affect the electron emission efficiency of the electron gun cathode. Furthermore, the evaporation of the platinum foil also reduces the bonding strength between the cathode tube and the cathode support tube, causing the cathode tube to detach from the cathode support tube. Summary of the Invention

[0004] In order to solve the above-mentioned problems in the prior art, namely, to solve the problem that the welding method of the existing electron gun heat shield assembly easily leads to a reduction in the electron emission effect of the cathode and poor bonding, the present invention provides a welding method for an electron gun cathode heat shield assembly, wherein the cathode heat shield assembly includes a heat shield tube having a mounting cavity, a cathode assembly disposed within the mounting cavity, and a thermal subassembly; in the axial direction of the heat shield tube, the thermal subassembly is disposed below the cathode assembly;

[0005] The cathode assembly includes a cathode cylinder having a receiving cavity, a cathode cake disposed at the upper end of the cathode cylinder and covering the receiving cavity, and a cathode support cylinder sleeved on the outer circumference and lower end of the cathode cylinder. A heater passage hole is provided at the bottom of the cathode support cylinder, and the heater passage hole is connected to the receiving cavity. The welding method of the cathode heat shield assembly includes the following steps:

[0006] Compressing step: applying pre-pressure to the cathode cylinder and the cathode support cylinder to compress the contact surface of the cathode cylinder and the cathode support cylinder to form a conductive path;

[0007] Resistance welding step: applying power to the cathode tube and the cathode support tube to form a nugget at the connection between the cathode tube and the cathode support tube;

[0008] Power-off forging steps: stop supplying power to the cathode cylinder and the cathode support cylinder, and maintain the pressure between the cathode cylinder and the cathode support cylinder to allow the molten core to cool and crystallize.

[0009] Preferably, the welding method of the cathode heat shield assembly further includes a preheating pulse step, and the preheating pulse step is provided between the pressing step and the resistance welding step;

[0010] Preheating pulse step: applying a low voltage to the cathode cylinder and the cathode support cylinder to increase the temperature of the contact surface between the cathode cylinder and the cathode support cylinder.

[0011] Preferably, the welding method of the cathode heat shield assembly further includes a pressurizing step, and the pressurizing step is provided between the resistance welding step and the power-off forging step;

[0012] Pressurizing step: further applying pressure between the cathode cylinder and the cathode support cylinder to compact the nugget produced in the resistance welding step.

[0013] Preferably, the heater assembly includes a nickel tube and a heater partially sleeved inside the nickel tube, and the heater extends along the axial direction of the heat shield tube until it passes through the heater through hole and enters the accommodating cavity of the cathode tube.

[0014] Preferably, the accommodating cavity contains aluminum oxide powder, and when the heater generates heat, the aluminum oxide powder is sintered into a solid state.

[0015] Preferably, the cathode heat shield assembly further comprises a cathode base, which is arranged at the lower portion of the heat shield tube and partially inserted into the installation cavity so that the upper end surface of the cathode base abuts against the lower end surface of the cathode support tube.

[0016] Preferably, a through hole is provided on the cathode base, and the thermal subassembly can pass through the through hole and enter into the interior of the heat shield tube.

[0017] Preferably, the cathode support cylinder is provided with a heat-insulating groove in a radial direction, and the height of the heat-insulating groove in the vertical direction is lower than the bottom end of the cathode cylinder.

[0018] Preferably, the cathode cylinder and the cathode support cylinder are both configured to be structures made of molybdenum-rhenium alloy.

[0019] Preferably, the lower end portion of the cathode cake is embedded in the upper end surface of the cathode cylinder, and the cathode cake is connected to the cathode cylinder by welding.

[0020] Those skilled in the art will appreciate that the aforementioned welding method of the electron gun cathode heat shield assembly of the present invention has at least the following beneficial effects:

[0021] 1. By configuring the cathode assembly to include a cathode tube, a cathode cake arranged at the upper end of the cathode tube, and a cathode support tube sleeved on the outer circumferential surface and the lower end of the cathode tube, the cathode tube can be directly in contact with the cathode support tube and welded. On the premise of ensuring the welding effect of the cathode tube and the cathode support tube, it is also possible to avoid the generation of harmful impurities in the electron gun heat shield assembly during the heating process, which may lead to a decrease in the ability of the cathode assembly to emit electrons.

[0022] By providing a pressing step in the welding method of the cathode heat shield assembly to apply pre-pressure to the cathode tube and the cathode support tube, the contact surface of the cathode tube and the cathode support tube can be pressed to form a conductive path, so as to facilitate the passage of current during the subsequent power-on process, and avoid the phenomenon that the connection between the cathode tube and the cathode support tube is not tight and there is a gap, which causes the current to be unable to flow and the heat to be unable to be generated.

[0023] By arranging a resistance welding step after the pressing step, and setting the resistance welding step to energize the cathode tube and the cathode support tube, so that a molten core is formed at the connection between the cathode tube and the cathode support tube, the materials of the cathode tube and the cathode support tube can be tightly combined through the molten core, thereby ensuring good welding firmness between the cathode tube and the cathode support tube.

[0024] By arranging a power-off forging step after the resistance welding step, and setting the power-off forging step to stop supplying power to the cathode tube and the cathode support tube, the pressure between the cathode tube and the cathode support tube is maintained so that the molten core can cool and crystallize under the action of pressure, forming a weld with dense structure, no shrinkage holes and no cracks, so as to further ensure the welding firmness between the cathode tube and the cathode support tube.

[0025] 2. By providing a preheating pulse step in the welding method of the electron gun cathode heat shield assembly, and arranging the preheating pulse step between the pressing step and the resistance welding step, the electrode can apply a low voltage to the cathode tube and the cathode support tube, so that the temperature at the contact surface of the cathode tube and the cathode support tube is increased, which is convenient for improving the metal plasticity of the cathode tube and the cathode support tube, making it easier for the cathode support tube and the cathode tube to fit tightly, and preventing spattering during the welding process.

[0026] 3. By designing a pressurizing step in the welding method of the cathode heat shield assembly, and arranging the pressurizing step between the resistance welding step and the power-off forging step, the molten core formed by the resistance welding step can be squeezed in the pressurizing step, so that the molten core can be compacted, preventing the molten core from generating cracks or shrinkage cavities during the cooling process, and improving the stability of the cathode heat shield assembly after welding.

[0027] 4. By configuring the heater assembly to include a nickel tube and a heater partially sheathed within the nickel tube, the nickel tube can protect the portion of the heater that is not inserted into the housing cavity, thereby preventing damage or deformation of the heater caused by vibration of the electron gun during operation. The heater can also extend axially along the heat shield tube until it passes through the heater passage hole of the cathode support tube and enters the housing cavity of the cathode tube, thereby allowing the heater to heat the cathode tube and the cathode cake, thereby generating electrons on the cathode cake or the cathode tube.

[0028] 5. By radially opening a heat-insulating groove on the cathode support tube and setting the groove vertically lower than the bottom of the cathode tube, the heat in the cathode tube is blocked by the groove, preventing the heat from flowing downward beyond the groove, which would lower the temperature of the cathode tube and cathode cake and reduce the ability to generate electrons. At the same time, the heat-insulating groove ensures that the space below the groove is maintained at a relatively low temperature, preventing excessive temperature increases from damaging the electron gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Some embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0030] Figure 1 2 is a schematic structural diagram of the cathode heat shield assembly of the electron gun in the first embodiment of the present invention;

[0031] Figure 2 This is a flow chart of the welding method of the electron gun cathode heat shield assembly in the first embodiment of the present invention;

[0032] Figure 3 This is a flow chart of the welding method of the electron gun cathode heat shield assembly in the second embodiment of the present invention;

[0033] Figure 4 This is a flow chart of the welding method of the electron gun cathode heat shield assembly in the third embodiment of the present invention.

[0034] List of reference numerals:

[0035] 1-heat shield tube; 2-cathode assembly; 21-cathode tube; 211-accommodation cavity; 22-cathode cake; 23-cathode support tube; 231-heater passage hole; 232-thermal insulation groove; 3-heater assembly; 31-nickel tube; 32-heater; 4-aluminum oxide powder; 5-cathode base. DETAILED DESCRIPTION

[0036] It should be understood by those skilled in the art that the embodiments described below are only some embodiments of the present invention, which are intended to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those skilled in the art without creative work should still fall within the scope of protection of the present invention.

[0037] It should be noted that in the description of the present invention, terms such as "center," "upper," "lower," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. These are merely for ease of description and do not indicate or imply that the device or element described must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] Furthermore, it should be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0039] The following further explains a welding method of an electron gun cathode heat shield assembly of the present invention with reference to the accompanying drawings and in combination with specific embodiments:

[0040] In a first embodiment of the present invention:

[0041] like Figure 1As shown, the cathode heat shield assembly includes a heat shield tube 1 having a mounting cavity, a cathode assembly 2 disposed within the mounting cavity, and a thermal subassembly 3. In the axial direction of the heat shield tube 1, the thermal subassembly 3 is disposed below the cathode assembly 2. The thermal subassembly 3 can be connected to an external power source, enabling the thermal subassembly 3 to generate heat, thereby enabling the cathode assembly 2 to generate a large number of thermal electrons. The thermal subassembly 3 and the cathode assembly 2 are disposed within the mounting cavity of the heat shield tube 1, so that the heat shield tube 1 can define the position of the thermal subassembly 3 and the cathode assembly 2, thereby preventing the thermal subassembly 3 or the cathode assembly 2 from vibrating or falling off during the operation of the electron gun. At the same time, the heat shield tube 1 can also prevent the heat generated by the thermal subassembly 3 from diffusing outward, thereby maintaining a constant temperature inside the heat shield tube 1 and preventing damage to other components of the electron gun due to heat diffusion within the heat shield tube 1.

[0042] Continue to refer to Figure 1 The cathode assembly 2 includes a cathode cylinder 21 having a receiving cavity 211, a cathode cake 22 disposed at the upper end of the cathode cylinder 21 and covering the receiving cavity 211, and a cathode support cylinder 23 sleeved on the outer circumference and lower end of the cathode cylinder 21. The bottom of the cathode support cylinder 23 is provided with a heater through hole 231, and the heater through hole 231 is connected to the receiving cavity 211.

[0043] Those skilled in the art will appreciate that by configuring the cathode assembly 2 to include a cathode tube 21, a cathode cake 22 disposed at the upper end of the cathode tube 21, and a cathode support tube 23 sleeved on the outer circumferential surface and the lower end of the cathode tube 21, the cathode tube 21 can be in direct contact with and welded to the cathode support tube 23. While ensuring the welding effect of the cathode tube 21 and the cathode support tube 23, it is also possible to avoid the generation of harmful impurities by the electron gun heat shield assembly during the heating process, thereby preventing the cathode assembly 2 from having a reduced ability to emit electrons.

[0044] like Figure 2 As shown, the present invention also provides a method for welding a cathode heat shield assembly, which specifically includes the following steps:

[0045] Compressing step: applying pre-pressure to the cathode cylinder 21 and the cathode support cylinder 23 to compress the contact surface of the cathode cylinder 21 and the cathode support cylinder 23 to form a conductive path;

[0046] Resistance welding step: applying power to the cathode cylinder 21 and the cathode support cylinder 23 to form a nugget at the connection between the cathode cylinder 21 and the cathode support cylinder 23;

[0047] Power-off forging step: stop supplying power to the cathode cylinder 21 and the cathode support cylinder 23 and maintain the pressure between the cathode cylinder 21 and the cathode support cylinder 23 to allow the molten core to cool and crystallize.

[0048] It will be understood by those skilled in the art that, by providing a pressing step in the welding method of the cathode heat shield assembly to apply pre-pressure to the cathode tube 21 and the cathode support tube 23, the contact surfaces of the cathode tube 21 and the cathode support tube 23 can be pressed to form a conductive path, so as to facilitate the passage of current during the subsequent power-on process, and avoid the phenomenon that the cathode tube 21 and the cathode support tube 23 are not tightly connected or there is a gap, which causes the current to be unable to flow and the heat to be unable to be generated.

[0049] By arranging a resistance welding step after the pressing step, and setting the resistance welding step to energize the cathode tube 21 and the cathode support tube 23, so that a molten core is formed at the connection between the cathode tube 21 and the cathode support tube 23, the materials of the cathode tube 21 and the cathode support tube 23 can be tightly combined through the molten core, thereby ensuring that the cathode tube 21 and the cathode support tube 23 have good welding firmness.

[0050] By arranging a power-off forging step after the resistance welding step, and setting the power-off forging step to stop supplying power to the cathode cylinder 21 and the cathode support cylinder 23, the pressure between the cathode cylinder 21 and the cathode support cylinder 23 is maintained, so that the molten core can cool and crystallize under the action of pressure, forming a weld with a dense structure, no shrinkage holes and no cracks, so as to further ensure the welding firmness between the cathode cylinder 21 and the cathode support cylinder 23.

[0051] As a preferred implementation of the present invention, Figure 1 As shown, the heater assembly 3 includes a nickel tube 31 and a heater 32 partially sleeved inside the nickel tube 31 . The heater 32 extends along the axial direction of the heat shield tube 1 until it passes through the heater through hole 231 and enters the accommodating cavity 211 of the cathode tube 21 .

[0052] Those skilled in the art will appreciate that by configuring the heater assembly 3 to include a nickel tube 31 and a heater 32 partially sheathed within the nickel tube 31, the nickel tube 31 can protect the portion of the heater 32 that does not extend into the accommodating cavity 211, thereby preventing the heater 32 from being damaged or deformed due to vibrations generated by the electron gun during operation. Furthermore, the heater 32 can extend axially along the heat shield tube 1 until it passes through the heater passage hole 231 of the cathode support tube 23 and enters the accommodating cavity 211 of the cathode tube 21, thereby allowing the heater 32 to heat the cathode tube 21 and the cathode cake 22, thereby generating electrons on the cathode cake 22 or the cathode tube 21.

[0053] As a preferred implementation of the present invention, Figure 1 As shown, the accommodating cavity 211 contains aluminum oxide powder 4. When the heater 32 generates heat, the aluminum oxide powder 4 is sintered into a solid state.

[0054] It will be understood by those skilled in the art that by arranging alumina powder 4 in the accommodating cavity 211, the alumina powder 4 can be sintered into a solid state when the heater 32 generates heat, so as to fix and limit the cathode tube 21 and the heater 32 inserted into the accommodating cavity 211, thereby avoiding the heater 32 from shaking during the operation of the electron gun, which may lead to unstable working performance of the electron gun.

[0055] As a preferred implementation of the present invention, Figure 1 As shown, the cathode heat shield assembly further includes a cathode base 5 , which is disposed at the lower portion of the heat shield tube 1 and partially inserted into the mounting cavity so that the upper end surface of the cathode base 5 abuts against the lower end surface of the cathode support tube 23 .

[0056] Those skilled in the art will appreciate that by providing the cathode base 5 at the lower portion of the heat shield tube 1 and arranging the cathode base 5 to abut against the cathode support tube 23, the cathode base 5 can form a seal with the lower portion of the heat shield tube 1, preventing heat from the heat shield tube 1 from dissipating outward. Furthermore, the cathode base 5 can abut against the cathode support tube 23 to define the position of the cathode support tube 23 and prevent the cathode support tube 23 and the cathode tube 21 from sliding downward.

[0057] As a preferred implementation of the present invention, Figure 1 As shown, a through hole is provided on the cathode base 5 , and the thermal subassembly 3 can enter into the interior of the heat shield tube 1 through the through hole.

[0058] Those skilled in the art will understand that the through hole not only allows the thermal sub-assembly 3 to enter the interior of the heat shield tube 1, but also provides radial position limitation for the thermal sub-assembly 3 by contacting the thermal sub-assembly 3, thereby preventing the thermal sub-assembly 3 from shaking left and right inside the heat shield tube 1.

[0059] As a preferred implementation of the present invention, Figure 1 As shown, the cathode support cylinder 23 is provided with a heat-insulating groove 232 in the radial direction, and the height of the heat-insulating groove 232 in the vertical direction is lower than the bottom end of the cathode cylinder 21 .

[0060] Those skilled in the art will appreciate that by radially defining the heat-insulating groove 232 on the cathode support tube 23 and vertically positioning the heat-insulating groove 232 lower than the bottom of the cathode tube 21, the heat within the cathode tube 21 is blocked by the heat-insulating groove 232, thereby preventing the heat within the heat-insulating groove 232 from transferring downward beyond the heat-insulating groove 232, thereby reducing the temperature of the cathode tube 21 and cathode cake 22 and the ability to generate electrons. Furthermore, the heat-insulating groove 232 ensures that the space below the heat-insulating groove 232 is maintained at a relatively low temperature, preventing damage to the electron gun from occurring due to excessive temperature increases.

[0061] As a preferred implementation of the present invention, Figure 1 As shown, the lower end portion of the cathode cake 22 is embedded in the upper end surface of the cathode cylinder 21 , and the cathode cake 22 and the cathode cylinder 21 are connected by welding.

[0062] Those skilled in the art will understand that by embedding the lower end of the cathode cake 22 on the upper end surface of the cathode tube 21 and setting the cathode cake 22 to be welded to the cathode tube 21, the connection between the cathode cake 22 and the cathode tube 21 is ensured to be stable, thereby avoiding the phenomenon of the cathode cake 22 falling off the cathode tube 21.

[0063] As a preferred implementation of the present invention, the cathode cylinder 21 and the cathode support cylinder 23 are both configured to be made of a molybdenum-rhenium alloy.

[0064] It will be understood by those skilled in the art that by configuring the cathode tube 21 and the cathode support tube 23 to be made of molybdenum-rhenium alloy, the cathode tube 21 and the cathode support tube 23 can have the same melting point, and thus when the cathode tube 21 and the cathode support tube 23 are subjected to the resistance welding step, the contact surface of the cathode tube 21 and the cathode support tube 23 can be melted synchronously, ensuring that the cathode tube 21 can be tightly combined with the material of the cathode support tube 23, so as to ensure good welding stability.

[0065] In a second embodiment of the present invention:

[0066] like Figure 3 As shown, compared with the first embodiment, the welding method of the cathode heat shield assembly in this embodiment includes a preheating pulse step, and the preheating pulse step is arranged between the pressing step and the resistance welding step.

[0067] Therefore, the welding method of the cathode heat shield assembly in this embodiment includes the following steps:

[0068] Compressing step: applying pre-pressure to the cathode cylinder 21 and the cathode support cylinder 23 to compress the contact surface of the cathode cylinder 21 and the cathode support cylinder 23 to form a conductive path;

[0069] Preheating pulse step: applying a low voltage to the cathode cylinder 21 and the cathode support cylinder 23 to increase the temperature of the contact surface between the cathode cylinder 21 and the cathode support cylinder 23;

[0070] Resistance welding step: applying power to the cathode cylinder 21 and the cathode support cylinder 23 to form a nugget at the connection between the cathode cylinder 21 and the cathode support cylinder 23;

[0071] Power-off forging step: stop supplying power to the cathode cylinder 21 and the cathode support cylinder 23 and maintain the pressure between the cathode cylinder 21 and the cathode support cylinder 23 to allow the molten core to cool and crystallize.

[0072] It will be understood by those skilled in the art that, by providing a preheating pulse step in the welding method of the electron gun cathode heat shield assembly, and arranging the preheating pulse step between the pressing step and the resistance welding step, the electrode can apply a low voltage to the cathode tube 21 and the cathode support tube 23, so that the temperature at the contact surface of the cathode tube 21 and the cathode support tube 23 is increased, thereby facilitating the improvement of the metal plasticity of the cathode tube 21 and the cathode support tube 23, making it easier for the cathode support tube 23 and the cathode tube 21 to fit tightly together, and preventing spattering during the welding process.

[0073] In a third embodiment of the present invention:

[0074] like Figure 4 As shown, compared with the first and second embodiments, the welding method of the cathode heat shield assembly in this embodiment further includes a pressurizing step, which is arranged between the resistance welding step and the power-off forging step.

[0075] Therefore, the welding method of the cathode heat shield assembly in this embodiment includes the following steps:

[0076] Compressing step: applying pre-pressure to the cathode cylinder 21 and the cathode support cylinder 23 to compress the contact surface of the cathode cylinder 21 and the cathode support cylinder 23 to form a conductive path;

[0077] Preheating pulse step: applying a low voltage to the cathode cylinder 21 and the cathode support cylinder 23 to increase the temperature of the contact surface between the cathode cylinder 21 and the cathode support cylinder 23;

[0078] Resistance welding step: applying power to the cathode cylinder 21 and the cathode support cylinder 23 to form a nugget at the connection between the cathode cylinder 21 and the cathode support cylinder 23;

[0079] Pressurizing step: applying further pressure between the cathode cylinder 21 and the cathode support cylinder 23 to compact the nugget produced in the resistance welding step;

[0080] Power-off forging step: stop supplying power to the cathode cylinder 21 and the cathode support cylinder 23 and maintain the pressure between the cathode cylinder 21 and the cathode support cylinder 23 to allow the molten core to cool and crystallize.

[0081] It will be understood by those skilled in the art that by designing a pressurizing step in the welding method of the cathode heat shield assembly and arranging the pressurizing step between the resistance welding step and the power-off forging step, the molten core formed by the resistance welding step can be squeezed in the pressurizing step so that the molten core can be compacted, thereby preventing the molten core from generating cracks or shrinkage cavities during the cooling process, and improving the stability of the cathode heat shield assembly after welding.

[0082] So far, the technical solutions of the present invention have been described in conjunction with the above multiple embodiments. However, it is easy for those skilled in the art to understand that the scope of protection of the present invention is not limited to these specific embodiments. Without departing from the technical principles of the present invention, those skilled in the art may split and combine the technical solutions in the above various embodiments, and may also make equivalent changes or replacements to the relevant technical features. Any changes, equivalent replacements, improvements, etc. made within the technical concept and / or technical principles of the present invention will fall within the scope of protection of the present invention.

Claims

1. A welding method for an electron gun cathode heat shield assembly, characterized in that: The cathode heat shield assembly includes a heat shield tube having an installation cavity, a cathode assembly and a thermal subassembly arranged inside the installation cavity; in the axial direction of the heat shield tube, the thermal subassembly is arranged at the lower part of the cathode assembly; The cathode assembly includes a cathode cylinder having a receiving cavity, a cathode cake disposed at the upper end of the cathode cylinder and covering the receiving cavity, and a cathode support cylinder sleeved on the outer circumference and lower end of the cathode cylinder. A heater passage hole is provided at the bottom of the cathode support cylinder, and the heater passage hole is connected to the receiving cavity. The welding method of the cathode heat shield assembly includes the following steps: Compressing step: applying pre-pressure to the cathode cylinder and the cathode support cylinder to compress the contact surface of the cathode cylinder and the cathode support cylinder to form a conductive path; Resistance welding step: applying power to the cathode tube and the cathode support tube to form a nugget at the connection between the cathode tube and the cathode support tube; Power-off forging steps: stop supplying power to the cathode cylinder and the cathode support cylinder, and maintain the pressure between the cathode cylinder and the cathode support cylinder to allow the molten core to cool and crystallize; The heater assembly includes a nickel tube and a heater partially sleeved inside the nickel tube, wherein the heater extends along the axial direction of the heat shield tube until passing through the heater hole and entering the accommodating cavity of the cathode tube; Aluminum oxide powder is contained in the accommodating cavity, and when the heater generates heat, the aluminum oxide powder is sintered into a solid state.

2. The welding method of the electron gun cathode heat shield assembly according to claim 1, characterized in that: The welding method of the cathode heat shield assembly further includes a preheating pulse step, wherein the preheating pulse step is provided between the pressing step and the resistance welding step; Preheating pulse step: applying a low voltage to the cathode cylinder and the cathode support cylinder to increase the temperature of the contact surface between the cathode cylinder and the cathode support cylinder.

3. The welding method of the electron gun cathode heat shield assembly according to claim 2, characterized in that: The welding method of the cathode heat shield assembly further includes a pressurizing step, wherein the pressurizing step is provided between the resistance welding step and the power-off forging step; Pressurizing step: further applying pressure between the cathode cylinder and the cathode support cylinder to compact the nugget produced in the resistance welding step.

4. The welding method of the electron gun cathode heat shield assembly according to claim 1, characterized in that: The cathode heat shield assembly further includes a cathode base, which is arranged at the lower portion of the heat shield tube and partially inserted into the installation cavity so that the upper end surface of the cathode base abuts against the lower end surface of the cathode support tube.

5. The welding method of the electron gun cathode heat shield assembly according to claim 4, characterized in that: The cathode base is provided with a through hole, and the thermal subassembly can pass through the through hole and enter the interior of the heat shield tube.

6. The welding method of the electron gun cathode heat shield assembly according to claim 1, characterized in that: The cathode support cylinder is provided with a heat-insulating groove along the radial direction, and the height of the heat-insulating groove in the vertical direction is lower than the bottom end of the cathode cylinder.

7. The welding method of the electron gun cathode heat shield assembly according to claim 1, characterized in that: The cathode cylinder and the cathode support cylinder are both configured to be structures made of molybdenum-rhenium alloy.

8. The welding method of the electron gun cathode heat shield assembly according to claim 1, characterized in that: The lower end portion of the cathode cake is embedded in the upper end surface of the cathode cylinder, and the cathode cake is welded to the cathode cylinder.

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