Anode assembly and method of processing thereof

Abstract

The application belongs to the technical field of X-ray tubes, and discloses an anode assembly and a processing method thereof. The anode assembly comprises a molybdenum reflector, a molybdenum rotor assembly and an intermediate layer. The intermediate layer is made of metal material and is arranged between the molybdenum reflector and the molybdenum rotor assembly by using the processing method. In the heating process, the intermediate layer can effectively absorb and buffer thermal stress and shrinkage stress generated from the molybdenum components on both sides due to heating and cooling through plastic deformation of the intermediate layer, thereby greatly reducing the risk of micro-cracks caused by stress concentration. Moreover, since the chemical affinity of the intermediate layer to impurity atoms is higher than that of molybdenum material, in a protective atmosphere or a vacuum environment, the intermediate layer can be ensured to preferentially react with the harmful impurities in the interface area during the welding process to form stable compounds, thereby preventing the impurities from segregating at the grain boundaries of molybdenum, significantly improving the microstructure and toughness of the molybdenum heat-affected zone, and enhancing the anti-grain boundary cracking ability.

Description

Technical Field

[0001] This invention relates to the field of X-ray tube technology, and in particular to an anode assembly and its processing method. Background Technology

[0002] In the manufacturing process of CT tubes, in order to reduce the heat generated by the target disk in the X-ray tube from being conducted to the bearing and to reduce the wear caused by the bearing under high temperature and high speed rotation, heat reflectors are often installed on the outside of the rotor assembly to reflect the heat radiated to the bearing back, thereby reducing the heat conduction to the bearing.

[0003] Molybdenum metal is a preferred material for manufacturing X-ray tube anode components and reflectors due to its high melting point (approximately 2620℃), excellent high-temperature strength, and good X-ray penetrability. Specifically, the rotor assembly is preferably made of TZM molybdenum alloy, and the reflector is preferably made of pure molybdenum. In actual production, the reflector and rotor assembly are typically assembled and fixed using direct molybdenum-molybdenum connections (including Mo-Mo or Mo-TZM connections), such as laser welding or electron beam welding.

[0004] However, molybdenum materials exhibit poor plasticity and low toughness at room temperature. During welding, the joint area experiences intense localized heating and rapid cooling, generating significant welding thermal stress. Since molybdenum cannot effectively release this stress through plastic deformation, stress becomes highly concentrated in the weld and heat-affected zone. Simultaneously, molybdenum is extremely sensitive to impurity atoms such as oxygen, nitrogen, and carbon, and tends to segregate at grain boundaries at high temperatures, severely weakening grain boundary bonding and exacerbating material brittleness.

[0005] The combined effects of stress concentration and grain boundary weakening make it extremely easy for microcracks to initiate in the recrystallization zone or weld. These cracks will further propagate under the cyclic thermal shocks and mechanical vibrations experienced by the connection structure during subsequent operation, eventually leading to the failure of the connection structure and seriously affecting the service life and reliability of the anode assembly and even the entire X-ray tube.

[0006] To address the aforementioned issues, existing technologies primarily employ two approaches: First, optimizing process parameters such as power, speed, vacuum level, and protective gas flow rate to control heat input and reduce temperature gradients in the fastening structure area, thereby lowering thermal stress. Second, after molybdenum-molybdenum processing and assembly, the anode assembly undergoes low-temperature annealing. Typically, the assembly is heated to 500℃-700℃, held for 2-4 hours, and then cooled in the furnace. This heat treatment causes metal atoms in the processed area to diffuse, mitigating lattice distortion, releasing some residual stress, and reducing the risk of crack formation.

[0007] However, the first solution for reducing heat input to reduce thermal stress often leads to insufficient penetration, and the carrying capacity of the anode assembly is reduced, which is difficult to meet the demand of high power load; the second solution increases the production process and cycle, and if not properly controlled during heat treatment, it is easy to cause deformation of the assembly, affecting the dimensional accuracy.

[0008] Therefore, the above problems need to be solved. SUMMARY

[0009] The purpose of the present application is to provide an anode assembly and a processing method thereof, to avoid the occurrence of micro-cracks in the recrystallization zone or weld between the reflector and the rotor assembly during connection or subsequent use, and to improve the service life and reliability of the anode assembly.

[0010] To achieve this purpose, the present application adopts the following technical solutions:

[0011] The anode assembly processing method comprises the following steps:

[0012] S1: providing a molybdenum reflector and a molybdenum rotor assembly;

[0013] S2: providing an intermediate layer made of a third metal material with metallurgical compatibility with the molybdenum reflector and the molybdenum rotor assembly;

[0014] S3: arranging the intermediate layer between the molybdenum reflector and the molybdenum rotor assembly;

[0015] S4: heating the connection area of the molybdenum reflector, the intermediate layer and the molybdenum rotor assembly in a protective atmosphere or vacuum environment, so that the three are combined by metallurgical method;

[0016] Wherein, the plasticity of the intermediate layer at room temperature and the affinity for impurity atoms in the interface region between the three are higher than that of molybdenum material, so that the thermal stress and shrinkage stress from the two sides of molybdenum material are absorbed and released by the plastic deformation of the intermediate layer during heating and cooling, and the intermediate layer reacts with the impurity atoms before the molybdenum material, thereby inhibiting the initiation and propagation of cracks in the recrystallization zone or weld of the molybdenum material.

[0017] As a preferred, the metal material is titanium, zirconium or liquid solder.

[0018] As a preferred, the metallurgical method is laser welding, argon arc welding or brazing.

[0019] As a preferred, the absolute value of the difference between the thermal expansion coefficient of the metal material and the thermal expansion coefficient of the molybdenum material is not greater than 5.0 μm / m·K.

[0020] Preferably, in S4, before heating the molybdenum reflector, the molybdenum rotor assembly and the metal intermediate layer, the molybdenum reflector, the molybdenum rotor assembly and the metal intermediate layer need to be ultrasonically cleaned and high-temperature degassed in a vacuum furnace.

[0021] An anode assembly comprising a molybdenum reflector, a molybdenum rotor assembly and an intermediate layer, the intermediate layer being arranged between the molybdenum reflector and the molybdenum rotor assembly and being made of a third metal material having metallurgical compatibility with the molybdenum reflector and the molybdenum rotor assembly, and the intermediate layer having higher plasticity at room temperature and higher affinity for impurity atoms in the interface region between the three than molybdenum, so as to absorb and release thermal stress and shrinkage stress from the two sides of molybdenum through its own plastic deformation during heating and cooling, and react with the impurity atoms before the molybdenum, thereby inhibiting the initiation and propagation of cracks in the recrystallization zone or the weld of the molybdenum.

[0022] Preferably, the intermediate layer is a cylindrical structure, the intermediate layer is screwed to the molybdenum rotor assembly, and the molybdenum reflector is screwed to the intermediate layer.

[0023] The intermediate layer is connected to the molybdenum rotor assembly and the molybdenum reflector by laser welding.

[0024] Preferably, the molybdenum reflector is screwed to the molybdenum rotor assembly, and the molybdenum reflector and the molybdenum rotor assembly form a receiving groove for accommodating the intermediate layer.

[0025] Preferably, the intermediate layer is a cylindrical structure formed by titanium or zirconium material, which is adapted to the profile of the receiving groove and is connected to the molybdenum rotor assembly and the molybdenum reflector by laser welding; or

[0026] The material of the intermediate layer is a liquid filler, which is filled in the receiving groove and is connected to the molybdenum rotor assembly and the molybdenum reflector by brazing.

[0027] Preferably, the molybdenum reflector is screwed to the molybdenum rotor assembly, the intermediate layer is a columnar structure, the columnar structure penetrates through the molybdenum reflector and is embedded in the molybdenum rotor assembly, and the columnar structure is connected to the molybdenum rotor assembly and the molybdenum reflector by argon arc welding.

[0028] The beneficial effects of the present application are as follows:

[0029] The present invention proposes an anode assembly and its processing method, in which an intermediate layer is provided between a molybdenum reflector and a molybdenum rotor assembly. During heating, the intermediate layer can effectively absorb and buffer the thermal and shrinkage stresses generated by heating and cooling of the molybdenum components on both sides through its own plastic deformation, greatly reducing the risk of microcracks initiating due to stress concentration. Furthermore, because the intermediate layer has a higher chemical affinity for impurity atoms than molybdenum material, it can avoid preferentially reacting with oxygen and nitrogen elements in the air to form an oxide film under a protective atmosphere or vacuum environment. This ensures that during welding, the intermediate layer preferentially reacts with these harmful impurities in the interface region to form stable compounds, thereby preventing impurities from segregating at the grain boundaries of molybdenum, significantly improving the microstructure and toughness of the heat-affected zone of molybdenum, and enhancing the resistance to grain boundary cracking. Attached Figure Description

[0030] Figure 1 This is a flowchart illustrating the anode component processing method in this invention;

[0031] Figure 2 This is one of the structural schematic diagrams of the anode assembly in this invention;

[0032] Figure 3 yes Figure 2 Enlarged view of a portion of point A in the middle;

[0033] Figure 4 This is the second schematic diagram of the anode assembly in this invention;

[0034] Figure 5 yes Figure 4 Enlarged view of a section at point B in the middle;

[0035] Figure 6 This is the third schematic diagram of the anode assembly in this invention;

[0036] Figure 7 yes Figure 6 Enlarged view of a section at point C.

[0037] In the picture:

[0038] 1. Molybdenum reflector; 2. Molybdenum rotor assembly; 3. Intermediate layer. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0040] In the description of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "above" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0042] In the description of the present embodiment, the terms "up", "down", "left", "right" and the like orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0043] Please refer to Figures 1 to 7 The present embodiment proposes a method for processing an anode assembly, which comprises the following steps:

[0044] S1: providing a molybdenum reflector 1 and a molybdenum rotor assembly 2;

[0045] S2: providing an intermediate layer 3 made of a third metal material having metallurgical compatibility with the molybdenum reflector 1 and the molybdenum rotor assembly 2, wherein the third metal refers to other metal materials different from the molybdenum reflector 1 and the molybdenum rotor assembly 2;

[0046] S3: arranging the intermediate layer 3 between the molybdenum reflector 1 and the molybdenum rotor assembly 2;

[0047] S4: heating the connection area of the molybdenum reflector 1, the intermediate layer 3 and the molybdenum rotor assembly 2 in a protective atmosphere or vacuum environment, so that the three are combined by metallurgical method;

[0048] The plasticity of the intermediate layer 3 at room temperature and the affinity to impurity atoms in the interface region between the three are higher than those of molybdenum material, so that the thermal stress and shrinkage stress from the two sides of molybdenum material can be absorbed and released by the plastic deformation of the intermediate layer 3 during heating and cooling, and the intermediate layer 3 reacts with impurity atoms before the molybdenum material, thereby inhibiting the initiation and propagation of cracks in the recrystallization zone or weld of the molybdenum material.

[0049] It should be noted that, whether pure molybdenum or TZM alloy, trace amounts of impurity atoms such as oxygen and nitrogen will inevitably be dissolved during the powder metallurgy or smelting preparation process. These impurity atoms exist in the form of interstitial solid solution inside the metal lattice, and when the three are combined in a metallurgical manner, oxygen, nitrogen and other impurity atoms can enter the grain boundary. When oxygen and nitrogen atoms accumulate to a certain extent in the grain boundary, they will form a stable oxide, nitride thin layer or segregation group, which can temporarily hinder grain growth, but severely weakens the metal bond between grain boundary atoms.

[0050] In the embodiment, the intermediate layer 3 is provided between the molybdenum reflector 1 and the molybdenum rotor assembly 2. During heating, the intermediate layer 3 can effectively absorb and buffer the thermal stress and shrinkage stress generated from the two sides of the molybdenum component due to heating and cooling through its own plastic deformation, greatly reducing the risk of microcracks caused by stress concentration. Moreover, the chemical affinity of the intermediate layer 3 to impurity atoms is higher than that of molybdenum material, so that in a protective atmosphere or vacuum environment, the intermediate layer 3 can avoid preferentially reacting with oxygen and nitrogen in the air, thereby ensuring that the intermediate layer 3 preferentially reacts with harmful impurities in the interface region during welding to form stable compounds, thereby preventing impurities from segregating at the molybdenum grain boundary, significantly improving the microstructure and toughness of the molybdenum grain boundary, and enhancing the grain boundary crack resistance.

[0051] Further, in S4, before heating the molybdenum reflector 1, the intermediate layer 3 and the molybdenum rotor assembly 2, the molybdenum reflector 1, the molybdenum rotor assembly 2 and the metal intermediate layer 3 need to be ultrasonically cleaned and degassed at high temperature using a vacuum furnace. It can be understood that after ultrasonic cleaning, physical contaminants such as grease, dust and processing residues on the surfaces of the three can be removed. The cleaning liquid used in the cleaning process is preferably alcohol or pure water to ensure the cleaning quality. Vacuum degassing not only removes water vapor, oxygen, nitrogen and other molecules adsorbed on the surface of the metal in the air, but also diffuses the trace amount of adsorbed gas or low-melting-point impurities inside the metal to the surface and removes them. The temperature in the vacuum furnace is preferably 400-700°C. In this way, the connection quality of the three in the metallurgical process can be further improved, and the service life of the anode assembly can be improved.

[0052] Based on the above, the embodiment also proposes an anode assembly, which comprises a molybdenum reflector 1, a molybdenum rotor assembly 2, and an intermediate layer 3 arranged between the molybdenum reflector 1 and the molybdenum rotor assembly 2, and the intermediate layer 3 is made of a third metal material having metallurgical compatibility with the molybdenum reflector 1 and the molybdenum rotor assembly 2, and the plasticity of the intermediate layer 3 at room temperature and the affinity for impurity atoms in the interface region between the three are higher than those of molybdenum material, so as to absorb and release the thermal stress and shrinkage stress from the two sides of molybdenum material through the plastic deformation of the intermediate layer 3 during the heating and cooling process, and react with the impurity atoms before the molybdenum material, thereby inhibiting the crack initiation and propagation at the recrystallization zone or the weld of the molybdenum material. The specific connection mode between the three can be referred to the specific embodiments 1 to 4. Specific embodiment 1

[0054] Please refer to Figure 2 and Figure 3 , the intermediate layer 3 is in a cylindrical structure, the intermediate layer 3 is screwed to the molybdenum rotor assembly 2, and the molybdenum reflector 1 is screwed to the intermediate layer 3; the intermediate layer 3 is connected with the molybdenum rotor assembly 2 and the molybdenum reflector 1 by laser welding. It can be understood that, when assembling the anode assembly, the molybdenum rotor assembly 2, the intermediate layer 3 and the molybdenum reflector 1 are pre-assembled by screw connection, and then finally connected by laser welding. The intermediate layer 3 in a cylindrical structure can form a circumferentially continuous and large-area matching surface between the molybdenum reflector 1 and the molybdenum rotor assembly 2, which can provide stable circumferential support for the molybdenum reflector 1, effectively inhibit the micro-vibration or deformation under high-speed rotation in work, and improve the structural dynamic stability.

[0055] Among them, the material of the intermediate layer 3 is preferably titanium material, the thermal expansion coefficient of titanium is about 8.6 μm / m·K, and the thermal expansion coefficient of molybdenum material is about 4.8 μm / m·K, the absolute value of the difference between the two is not greater than 5.0 μm / m·K, so as to help reduce the additional thermal stress generated due to uneven expansion and contraction during the heating and cooling process. And molybdenum and titanium are limitedly soluble in liquid state, at the welding interface, molybdenum and titanium will diffuse with each other to form a solid solution, and the strength and toughness thereof are between those of molybdenum and titanium, so as to provide a good performance gradient, avoid the sudden change of performance, and improve the bonding performance between molybdenum and titanium.

[0056] Compared with molybdenum material, the affinity of titanium material for oxygen: the absolute value of Gibbs free energy of generating TiO2 is more than 2 times of that of generating MoO3; the affinity of titanium material for nitrogen: the absolute value of Gibbs free energy of generating TiN is more than 10 times of that of generating Mo2N, and the higher the absolute value of Gibbs free energy, the stronger the "chemical glue" between the metal and the oxygen atom, and once combined, a stable structure with extremely low energy and extremely difficult to decompose can be formed.

[0057] Of course, in some other possible embodiments, the material of the intermediate layer 3 can also be zirconium.

[0058] For materials with an absolute difference between the two greater than 5.0 μm / m·K, such as nickel, the thermal expansion coefficient is about 13.4 μm / m·K, and at high temperatures, molybdenum and nickel will interact violently, forming a series of hard and brittle intermetallic compounds. These compounds, like ceramics, lack plasticity, are extremely susceptible to micro-cracks under the action of welding stress, and quickly expand to cause brittle fracture throughout the joint area. And because of the large difference in thermal expansion coefficient between the two, the shrinkage of nickel is much greater than that of molybdenum during subsequent cooling, which is easy to produce a huge shear stress at the interface, which is extremely easy to directly crack the already embrittled weld or compound layer, reducing the service life of the anode rotor.

[0059] In addition, the affinity of nickel for impurity atoms in the interface region between the three is less than that of molybdenum, so it cannot reduce the segregation of impurity atoms such as oxygen and nitrogen at the grain boundary, thereby failing to improve the embrittlement of the recrystallized region of molybdenum and the problem of weakening of the high-temperature grain boundary. On the contrary, the formation of brittle compounds and severe stress concentration will amplify the cracking tendency of the heat-affected zone of the molybdenum base material.

[0060] The specific processing steps are as follows:

[0061] After the molybdenum rotor assembly 2, the intermediate layer 3, and the molybdenum reflector 1 are cleaned by alcohol or pure water ultrasonic cleaning, high-temperature degassing is performed using a vacuum furnace, and the degassing temperature is 400 to 700°C. After degassing, the operator fixes the intermediate layer 3 on the molybdenum rotor assembly 2 by threading, and then fixes the molybdenum reflector 1 on the intermediate layer 3 by threading, forming a "molybdenum-titanium-molybdenum" sandwich structure. The welding components are placed on the laser welding table for laser processing and fixation, the position of the protective gas nozzle is adjusted to blow gas protection to the components, so that the three are in a protective atmosphere environment for metallurgical bonding. The protective gas used is argon with a purity of >99.9%, the laser welding time is 0.8 to 1.2 min, the welding power is 100 to 200 W, the defocusing amount is 0 to 0.2 mm, and the weld form is butt welding. Specific embodiment 2

[0063] The difference from the specific embodiment 1 is the way of pre-assembly.

[0064] Specifically, please refer to Figure 4 and Figure 5, the molybdenum reflector 1 is screwed on the molybdenum rotor assembly 2, and the molybdenum reflector 1 and the molybdenum rotor assembly 2 form a containing groove for containing the intermediate layer 3. It can be understood that, in the pre-assembly process, the molybdenum reflector 1 is directly screwed on the molybdenum rotor assembly 2, then the intermediate layer 3 is directly inserted into the containing groove between the molybdenum rotor assembly 2 and the molybdenum reflector 1, and then the molybdenum reflector 1 and the molybdenum rotor assembly 2 are connected by laser welding. The intermediate layer 3 is a cylindrical structure made of titanium or zirconium material, which is adapted to the shape of the containing groove.

[0065] It should be noted that, in addition to the pre-assembly, the specific processing steps in the embodiment are consistent with those in the specific embodiment 1, and will not be described in detail here. Specific embodiment 3

[0067] The difference between the specific embodiment 2 and the specific embodiment 3 is that the material of the intermediate layer 3 is different, and the welding method is also different.

[0068] Specifically, please refer to Figure 4 and Figure 5 The material of the intermediate layer 3 is liquid solder. After the molybdenum reflector 1 is screwed on the molybdenum rotor assembly 2, the liquid solder is filled in the containing groove, and the molybdenum reflector 1 and the molybdenum rotor assembly 2 are connected by brazing. It can be understood that the regular containing groove provides a continuous and complete flow channel for the liquid solder, so that the liquid solder is uniformly filled in the connecting interface between the molybdenum rotor assembly 2 and the molybdenum reflector 1, and defects such as incomplete filling or pores are avoided, so as to realize the metallurgical bonding of the full contact area of the three. The liquid solder is preferably a palladium-based solder, such as Pd-Ni, Pd-Co, Pd-Cu, etc., which has good wettability, can effectively dissolve the oxides on the surface of molybdenum, and has high joint strength, good ductility, and few brittle phases.

[0069] However, for nickel-based solder such as BNi-5, BNi-7, pure nickel foil, etc., it is easy to form brittle intermetallic compounds (such as NiMo, Ni4Mo) with molybdenum, which leads to the joint cracking at room temperature or thermal cycling.

[0070] It should be noted that molybdenum is easy to form a stable oxide film at high temperature, i.e. molybdenum trioxide, so that the liquid solder will gather into a spherical shape (contact angle > 90°) on the surface of the oxide film like water droplets on a lotus leaf, thereby preventing the liquid solder from being uniformly spread in the containing groove, i.e. an effective solder joint connection cannot be formed. Moreover, normal brazing involves a small amount of mutual dissolution and diffusion between the solder and the base material, forming a firm metallurgical bond (metallic bond). However, the formation of the oxide film is equivalent to the formation of a physical and chemical "barrier" between the two, which reduces the connection strength between the molybdenum reflector 1 and the molybdenum rotor assembly 2, and the two are easy to peel off from the interface under stress or thermal cycling.

[0071] Therefore, when brazing, the three are in a vacuum environment, such as 10 -3 Pa, preferably 5x10 -4 Pa, in a high vacuum environment, the formed molybdenum trioxide can be sublimed and removed to prevent the formation of new oxide films.

[0072] In some other possible embodiments, the three can also be in an ultra-high purity dry reducing atmosphere, such as pure hydrogen with a dew point of -40°C. Hydrogen can reduce molybdenum trioxide to molybdenum and water, thereby preventing the formation of molybdenum trioxide.

[0073] The specific processing steps are as follows:

[0074] The anode assembly, which has been pre-assembled by threads and placed with the palladium-based filler metal, is placed in a vacuum brazing furnace, the vacuum system is started, and the furnace cavity is pumped to a basic high vacuum, such as 5x10 -4 Pa, the anode assembly is heated to 800°C at a heating rate of 10°C / min to 15°C / min, and a preset time is maintained. This temperature is lower than the melting temperature of the palladium-based filler metal, but is sufficient to fully volatilize and decompose the moisture, grease and other contaminants adsorbed on the surface and inside of the anode assembly, and to be removed by the vacuum system. The preset time is determined according to the size and load of the anode assembly to ensure thorough degassing.

[0075] Subsequently, the temperature is raised from 800°C to 1260°C±10°C. At this temperature, the palladium-based filler metal can be melted into a liquid state and maintained for 10min to 20min to ensure that the liquid filler metal can fill every corner of the entire containing groove. And at high temperature, the trace amount of gas dissolved in the filler metal and the interface can further escape, reducing the porosity of the weld.

[0076] After heating is completed, the temperature is reduced to below 900°C at a rate of 5°C / min to 10°C / min to avoid the generation of huge internal stress or even cracks due to uneven shrinkage of molybdenum (brittle material) and the brazing seam caused by rapid cooling. After cooling to below 900°C, the main phase change and stress risk has passed, and the furnace cooling (power off natural cooling) can be switched to near room temperature. DETAILED DESCRIPTION 4

[0078] The same as in specific embodiments 1 and 2 is that the material selection of the intermediate layer 3 is the same, and the difference is that the shape of the intermediate layer 3 is different, and the connection method and the welding method are also different.

[0079] Specifically, please refer to Figure 6 and Figure 7, the molybdenum reflector 1 is screwed on the molybdenum rotor assembly 2, the intermediate layer 3 is a columnar structure, the columnar structure penetrates the molybdenum reflector 1 and is embedded in the molybdenum rotor assembly 2, and is connected with the molybdenum rotor assembly 2 and the molybdenum reflector 1 through argon arc welding. It can be understood that the columnar intermediate layer 3 can form a mechanical interlocking structure similar to a rivet between the molybdenum reflector 1 and the molybdenum rotor assembly 2, which can effectively resist the centrifugal force and tangential force of the molybdenum reflector 1 during high-speed rotation, prevent relative slipping of the interface, and improve the service life of the anode assembly.

[0080] The specific processing steps are as follows:

[0081] The molybdenum rotor assembly 2 is screwed with the molybdenum reflector 1, and the molybdenum rotor assembly 2 and the reserved hole on the molybdenum reflector 1 are arranged opposite to each other to form a containing groove. The intermediate layer 3, such as a titanium nail that is profiled to match the containing groove, is pressed into the containing groove to complete the pre-assembly of the anode assembly. Then, the anode assembly is placed in a welding tool, and it is ensured that the welding position is located at the joint between the molybdenum reflector 1 and the molybdenum rotor assembly 2 and the titanium nail, and the tungsten needle position of the welding gun is close to the titanium nail.

[0082] The welding parameters are set, the welding current is 120 to 130 A, the welding voltage is 12 to 16 V, the welding time is 0.1 to 0.3 s, and the argon protection gas is delivered 1 s in advance before welding. The high-purity argon gas is delivered at a flow rate of 10 L / min to 15 L / min, wherein the purity of the argon gas is ≥ 99.9%. The air around the weld area and the titanium nail is swept and replaced to establish a pure argon protection zone to prevent oxidation during the instant of arc striking. The argon protection gas is stopped 2 s after welding.

[0083] Obviously, the above embodiments of the present application are only examples for clarity, and are not intended to limit the embodiments of the present application. Those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. It is not necessary or possible to exhaust all embodiments here. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method of processing an anode assembly, characterized by, The method comprises the following steps: S1: providing a molybdenum reflector (1) and a molybdenum rotor assembly (2); S2: providing an intermediate layer (3) made of a third metal material having metallurgical compatibility with the molybdenum reflector (1) and the molybdenum rotor assembly (2); S3: arranging the intermediate layer (3) between the molybdenum reflector (1) and the molybdenum rotor assembly (2); S4: heating the connection area of the molybdenum reflector (1), the intermediate layer (3) and the molybdenum rotor assembly (2) in a protective atmosphere or a vacuum environment, so that the three are combined by metallurgy; The plasticity of the intermediate layer (3) at room temperature and the affinity to impurity atoms in the interface area between the three are higher than those of molybdenum, so that the thermal stress and shrinkage stress from the two sides of molybdenum are absorbed and released by the plastic deformation of the intermediate layer (3) during heating and cooling, and the intermediate layer (3) reacts with the impurity atoms before the molybdenum reacts with the impurity atoms, thereby inhibiting the initiation and expansion of cracks in the recrystallization zone or the weld of molybdenum.

2. The anode assembly processing method of claim 1, wherein The metal material is titanium, zirconium or liquid solder.

3. The anode assembly processing method of claim 1, wherein The metallurgical method is laser welding, argon arc welding or brazing.

4. The anode assembly processing method of claim 1, wherein The absolute value of the difference between the thermal expansion coefficient of the metal material and the thermal expansion coefficient of molybdenum is not greater than 5.0 μm / m·K.

5. The anode assembly processing method of claim 1, wherein In S4, before heating the molybdenum reflector (1), the intermediate layer (3) and the molybdenum rotor assembly (2), the molybdenum reflector (1), the molybdenum rotor assembly (2) and the metal intermediate layer (3) need to be ultrasonically cleaned and degassed at high temperature in a vacuum furnace.

6. An anode assembly characterised in that, The method comprises the following steps:

7. The anode assembly of claim 6, wherein, The intermediate layer (3) is a cylindrical structure, the intermediate layer (3) is screwed to the molybdenum rotor assembly (2), and the molybdenum reflector (1) is screwed to the intermediate layer (3); The intermediate layer (3) is connected to the molybdenum rotor assembly (2) and the molybdenum reflector (1) by laser welding.

8. The anode assembly of claim 6, wherein, The molybdenum reflector (1) is screwed to the molybdenum rotor assembly (2), and an accommodation groove for accommodating the intermediate layer (3) is formed between the molybdenum reflector (1) and the molybdenum rotor assembly (2).

9. The anode assembly of claim 8, wherein, The intermediate layer (3) is made of titanium or zirconium, which forms a cylindrical structure that is adapted to the profile of the accommodation groove and is connected to the molybdenum rotor assembly (2) and the molybdenum reflector (1) by laser welding; or The material of the intermediate layer (3) is liquid solder, which is filled in the accommodating groove and connected with the molybdenum rotor assembly (2) and the molybdenum reflector (1) through brazing.

10. The anode assembly of claim 6, wherein, The molybdenum reflector (1) is screwed on the molybdenum rotor assembly (2), the intermediate layer (3) is a columnar structure, the columnar structure penetrates the molybdenum reflector (1) and is embedded in the molybdenum rotor assembly (2), and is connected with the molybdenum rotor assembly (2) and the molybdenum reflector (1) through argon arc welding.

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