Thin-wall vacuum chamber machining method and arc-shaped forked thin-wall vacuum chamber

Abstract

The invention relates to the technical field of vacuum cavity machining, in particular to a thin-wall vacuum chamber machining method and an arc-shaped forked thin-wall vacuum chamber. The thin-wall vacuum chamber machining method comprises the steps that a thin-wall pipe is machined; the thin-walled pipe is fixed to the mold; the thin-walled tube is subjected to empty burning treatment and then put into a vacuum brazing furnace to be subjected to vacuum brazing; and the thin-walled pipe and the ultrahigh vacuum flange are installed and welded. The arc-shaped forked thin-wall vacuum chamber comprises a vacuum chamber main body, the vacuum chamber main body comprises a first vacuum chamber forming a part of the vacuum chamber main body in the length direction, and the head end of the first vacuum chamber serves as one end of the vacuum chamber main body and is provided with one ultrahigh vacuum flange; the second vacuum chamber and the third vacuum chamber are respectively connected to the tail end of the first vacuum chamber, the second vacuum chamber and the third vacuum chamber jointly form the rest part of the vacuum chamber main body in the length direction, and the tail end of the second vacuum chamber and the tail end of the third vacuum chamber are jointly provided with another ultrahigh vacuum flange.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum chamber processing, and particularly to a processing method for a thin-walled vacuum chamber and an arc-shaped bifurcated thin-walled vacuum chamber. Background Art

[0002] In a synchrotron device, a vacuum chamber provides a necessary vacuum environment for the stable operation of a beam. In order to reduce the influence of eddy current on the beam stability, stainless steel thin-walled tubes with a thickness in the range of 0.1 mm to 0.5 mm are usually used, and stiffeners are welded outside them to fabricate a thin-walled vacuum chamber with an arc-shaped bifurcated structure.

[0003] For a thin-walled vacuum chamber with a relatively large cross-sectional size, after processing, it should not only have sufficient structural strength and stiffness to withstand the atmospheric pressure difference, but also must meet strict geometric tolerance requirements, such as parameters like angle, radius, length, and flatness. In addition, no structural defects such as buckling and wrinkling should occur during the manufacturing process of the thin-walled vacuum chamber to ensure its final performance and reliability.

[0004] However, in current actual production, there are many problems when processing such thin-walled vacuum chambers using traditional processes. For example, when directly performing vacuum welding on a stainless steel thin-walled tube and a stiffener after positioning them with a fixed mold, situations such as serious deformation of the thin-walled tube, leakage of the weld seam, and insufficient overall structural strength often occur. These problems lead to a low product qualification rate, high manufacturing cost, and seriously affect the mass production and engineering application of thin-walled vacuum chambers. Summary of the Invention

[0005] The present invention provides a processing method for a thin-walled vacuum chamber and an arc-shaped bifurcated thin-walled vacuum chamber to solve the problems of low qualification rate, high manufacturing cost, and long processing cycle caused by large deformation and leakage when manufacturing a thin-walled stiffened vacuum chamber using traditional technologies, and to achieve improvement in manufacturing accuracy, structural reliability, and production efficiency, and reduction in manufacturing cost.

[0006] The present invention provides a processing method for a thin-walled vacuum chamber, including: processing a thin-walled tube; fixing the thin-walled tube to a mold; first performing an air burning treatment on the thin-walled tube, and then putting it into a vacuum brazing furnace for vacuum brazing; and welding the thin-walled tube with an ultra-high vacuum flange.

[0007] According to an embodiment of the present invention, before the step of processing the thin-walled tube, a titanium alloy plate pretreatment step is further included, which specifically includes: performing annealing heat treatment on the titanium alloy plate; leveling and cutting the titanium alloy plate to required dimensions, wherein the dimensional tolerance of cutting the titanium alloy plate is controlled within ±0.05 mm, and a margin of 1 - 2 mm is left in the length direction of the titanium alloy plate.

[0008] According to an embodiment of the present invention, the steps of processing the thin-walled tube include: ultrasonically cleaning the cut titanium alloy plate; first fixing the thin-walled tube by resistance welding; installing the internal and external toolings of the thin-walled tube in place after resistance welding; completing the welding of the thin-walled tube by laser welding; and performing vacuum leak detection after welding is completed.

[0009] According to an embodiment of the present invention, the steps of fixing the thin-walled tube to the mold include: sequentially placing the reinforced ribs that have been cut and polished in place according to the positions of the reinforced rib installation grooves in the brazing mold assembly; placing the thin-walled tube that has completed vacuum leak detection into the brazing mold assembly and making the reinforced ribs in close contact with the thin-walled tube; and closing and fixing the brazing mold assembly.

[0010] According to an embodiment of the present invention, the brazing mold assembly includes: a first brazing mold having a first mold space, in which a reinforced rib installation groove is provided, and a boss is provided around it, and a wedge-shaped positioning block is provided on the boss; a second brazing mold having a second mold space opposite to the first mold space, and a groove corresponding to the boss is provided around it, and a wedge-shaped positioning groove corresponding to the wedge-shaped positioning block is provided in the groove, and the first mold space and the second mold space are used to accommodate the thin-walled vacuum chamber formed by the thin-walled tube and the reinforced ribs; fastening screws for installing and fixing the first brazing mold and the second brazing mold; and the materials of the first brazing mold and the second brazing mold are Al2O3.

[0011] According to an embodiment of the present invention, the steps of performing air burning treatment on the thin-walled tube include: after fixing the thin-walled tube to the mold, placing the whole into a vacuum brazing furnace and leveling it with a height gauge; heating the vacuum brazing furnace to 900 - 1000 °C; performing heating and cooling in three stages within three hours; starting to cool with the furnace to room temperature after reaching the required temperature; checking whether the positions of the thin-walled tube and the reinforced ribs have changed, and performing vacuum leak detection.

[0012] According to an embodiment of the present invention, the steps of putting the thin-walled tube into the vacuum brazing furnace for vacuum brazing include: applying solder at the contact positions of the thin-walled tube and the reinforced ribs; after the thin-walled tube and the reinforced ribs are placed into the vacuum brazing furnace with the mold, leveling the brazing mold with the height gauge; heating the vacuum brazing furnace to 1050 - 1085 °C; performing heating and cooling in three stages, and taking it out after the temperature drops to room temperature to complete the processing.

[0013] The present invention also provides an arc-shaped bifurcated thin-wall vacuum chamber, which is processed and formed by using the thin-wall vacuum chamber processing method of the above-mentioned embodiment; the arc-shaped bifurcated thin-wall vacuum chamber includes a vacuum chamber main body, which is arc-shaped as a whole, and ultra-high vacuum flanges are respectively arranged at both ends of the vacuum chamber main body; the vacuum chamber main body includes: a first vacuum chamber, which constitutes a part of the length direction of the vacuum chamber main body, and the head end of the first vacuum chamber is used as one end of the vacuum chamber main body, and one of the ultra-high vacuum flanges is arranged thereon; a second vacuum chamber and a third vacuum chamber, which are respectively connected to the tail end of the first vacuum chamber, the second vacuum chamber and the third vacuum chamber together constitute the remaining part of the length direction of the vacuum chamber main body, and the tail ends of the second vacuum chamber and the third vacuum chamber are jointly provided with another ultra-high vacuum flange.

[0014] According to an embodiment of the present invention, the cross-sections of the first vacuum chamber, the second vacuum chamber and the third vacuum chamber are all rectangular; the cross-sections of the first vacuum chamber and the third vacuum chamber along the length direction are both consistent; the cross-section of the second vacuum chamber is trumpet-shaped along the length direction, and gradually becomes larger from the side close to the first vacuum chamber to the side far from the first vacuum chamber; the heights of the first vacuum chamber and the second vacuum chamber are the same, and the height of the third vacuum chamber is less than the height of the first vacuum chamber.

[0015] According to an embodiment of the present invention, the first vacuum chamber, the second vacuum chamber and the third vacuum chamber are respectively provided with a reinforcing rib structure, wherein: the second vacuum chamber includes a second thin-wall tube, one side of the second thin-wall tube facing the third vacuum chamber is a second tube side plate without a reinforcing rib structure, and at least one second longitudinal reinforcing rib extending along the length direction of the second vacuum chamber and a plurality of second transverse reinforcing ribs perpendicular to the second longitudinal reinforcing rib are arranged on the remaining three surfaces of the second thin-wall tube; the third vacuum chamber includes a third thin-wall tube, one side of the third thin-wall tube facing the second vacuum chamber is a third tube side plate without a reinforcing rib structure, and at least one third longitudinal reinforcing rib extending along the length direction of the third vacuum chamber and a plurality of third transverse reinforcing ribs perpendicular to the third longitudinal reinforcing rib are arranged on the remaining three surfaces of the third thin-wall tube; an equidistant structural gap is formed between the second tube side plate and the third tube side plate.

[0016] The thin-walled vacuum chamber processing method and the arc-shaped bifurcated thin-walled vacuum chamber provided by the present invention effectively reduce the longitudinal deformation and leakage risk of the thin-walled tube caused by thermal stress during the welding process through process improvements such as pre-burning the thin-walled tube and then performing vacuum brazing, improving the qualified rate and structural stability of the product. Using this thin-walled vacuum chamber processing method to manufacture an arc-shaped bifurcated thin-walled vacuum chamber not only ensures its sealing performance and mechanical strength under complex working conditions, but also significantly improves production efficiency and product utilization rate, reducing the processing cycle and manufacturing cost. At the same time, this method combines die fixing and ultra-high vacuum flange assembly welding processes to further enhance the overall performance of the thin-walled vacuum chamber.

[0017] In addition, the arc-shaped bifurcated thin-walled vacuum chamber structure proposed by the present invention integrates the functions originally realized by the cutting magnet vacuum chamber and the dipole magnet vacuum chamber into one, forming a bifurcated design including the first vacuum chamber, the second vacuum chamber and the third vacuum chamber, which not only meets the spatial layout requirements of the beam extraction system, but also is conducive to the miniaturization development of the synchrotron device. This structure simplifies the assembly process, reduces the number of vacuum cavities, thereby effectively reducing the equipment manufacturing and maintenance costs, and due to the adoption of the above-mentioned thin-walled vacuum chamber processing method, further ensures the reliability of the structure and the feasibility of engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a schematic flow chart of the thin-walled vacuum chamber processing method provided by the present invention.

[0020] Figure 2 It is a schematic structural diagram of the brazing die assembly used in the thin-walled vacuum chamber processing method of the present invention.

[0021] Figure 3 It is a schematic structural diagram of the first brazing die of the brazing die assembly of the present invention.

[0022] Figure 4 It is a schematic structural diagram of the second brazing die of the brazing die assembly of the present invention.

[0023] Figure 5 It is a schematic structural diagram of the arc-shaped bifurcated thin-walled vacuum chamber provided by the present invention.

[0024] Figure 6It is a partial enlarged structural schematic diagram of the second vacuum chamber and the third vacuum chamber of the arc-shaped bifurcated thin-walled vacuum chamber of the present invention.

[0025] Reference numerals: 100, thin-walled vacuum chamber; 200, first brazing die; 300, second brazing die; 202, boss; 204, wedge-shaped positioning block; 206, reinforcing rib installation groove; 208, fastening screw; 302, groove; 304, wedge-shaped positioning groove; 400, first vacuum chamber; 500, second vacuum chamber; 600, third vacuum chamber; 700, ultra-high vacuum flange; 502, second thin-walled tube; 504, second transverse reinforcing rib; 506, second longitudinal reinforcing rib; 508, second tube side plate; 602, third thin-walled tube; 604, third transverse reinforcing rib; 606, third longitudinal reinforcing rib; 608, third tube side plate. Specific embodiments

[0026] To make the objectives, technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the present invention with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation on the embodiments of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0028] The following will be combined with Figures 1-6 Describe the processing method of the thin-walled vacuum chamber of the present invention and the specific embodiments of the arc-shaped bifurcated thin-walled vacuum chamber.

[0029] The present invention provides a processing method for a thin-walled vacuum chamber, and the method includes the following: Step 110: Process the thin-walled tube. The thin-walled tube is subjected to precision forming processing. It is initially formed into the required arc-shaped and bifurcated structures through methods such as die pressing or roll bending, and surface cleaning and degreasing treatments are carried out on it. Among them, the material of the above thin-walled tube is preferably TC4, and the thickness is 0.1 - 0.2 mm. The thin-walled tube uses the titanium alloy TC4 material with higher strength limit and lighter weight, which improves the structural strength of the large-section arc-shaped bifurcated thin-walled vacuum chamber and meets the requirements of high stability and high reliability of the miniaturized medical synchrotron.

[0030] Step 120: Fix the thin-walled tube to the mold. The processed thin-walled tube is firmly connected to the mold to ensure no displacement or deformation during subsequent heat treatment and welding processes. The design of the mold matches the shape of the thin-walled tube, which can effectively control the distribution of thermal stress, prevent local collapse or wrinkling, and thus improve the dimensional accuracy and consistency of the overall structure.

[0031] Step 130: First, perform an air burning treatment on the thin-walled tube, and then place it in a vacuum brazing furnace for vacuum brazing. The thin-walled tube fixed to the mold is placed in a heating device for preheating and heat preservation treatment (i.e., air burning) in the state without solder to remove residual gases, moisture, and organic substances, and at the same time release the internal residual stress of the material. Subsequently, the assembly is transferred to a vacuum brazing furnace, and high-strength and high-sealing connections between various components are achieved using solder in a high-temperature vacuum environment. This process significantly reduces the problems of deformation and weld leakage caused by thermal stress concentration, and improves the qualified rate and structural reliability of the product.

[0032] Step 140: Weld the thin-walled tube to the ultra-high vacuum flange. After completing the vacuum brazing and cooling, the thin-walled vacuum chamber body is assembled and welded to the ultra-high vacuum flange of the standard specification. Before welding, it is preferable to perform precision machining on the flange and the end of the thin-walled tube to ensure that the mating surfaces fit tightly; in the welding process, high-energy beam welding technologies such as electron beam welding or laser welding can be used to achieve high-quality welding with deep penetration and low heat-affected zone, so as to ensure the airtightness and mechanical strength of the overall structure and meet the technical requirements of the ultra-high vacuum environment in the synchrotron system.

[0033] Furthermore, according to a method for processing a thin-walled vacuum chamber of the present invention, before the step of processing the thin-walled tube, it further includes a pretreatment step for the titanium alloy plate, which specifically includes: Step 101: Perform annealing heat treatment on the titanium alloy plate. Before processing, the titanium alloy plate is subjected to homogenization annealing treatment to eliminate the residual stress generated during the rolling process of the material, improve its plasticity and workability, and at the same time improve the dimensional stability during the subsequent forming process.

[0034] Step 102: Level the titanium alloy plate and cut it to the required size. When leveling with a leveler, ensure that the titanium alloy thin plate is flat. Control the dimensional tolerance of the cut titanium alloy plate within ±0.05 mm, and leave a margin of 1 - 2 mm in the length direction of the titanium alloy plate. Use high-precision leveling equipment to level the annealed titanium alloy plate to remove slight bending or wavy deformation generated during transportation or storage of the plate; then use laser cutting or precision shearing equipment to accurately cut the blank of the required shape and size according to the design drawing. Preferably, strictly control the cutting tolerance within ±0.05 mm to ensure the consistency and accuracy of subsequent forming processing. A margin of 1 - 2 mm can be reserved in the length direction to facilitate compensation for possible shrinkage or misalignment during subsequent processing, thereby ensuring the geometric accuracy and assembly requirements of the final product.

[0035] Further, according to a method for processing a thin-walled vacuum chamber of the present invention, the steps for processing the thin-walled tube include: Step 111: Ultrasonically clean the cut titanium alloy plate. Before processing the titanium alloy plate into a thin-walled tube, use a multi-pass ultrasonic cleaning process to remove oil stains, metal chips, and other micron-level contaminants on the surface of the plate to ensure that the surface cleanliness of the material meets the usage requirements in a high-vacuum environment, thereby improving the subsequent welding quality and structural reliability.

[0036] Step 112: First, fix the thin-walled tube by resistance welding. Roll the cleaned titanium alloy plate into a thin-walled tubular structure of the required shape, and perform preliminary positioning welding at the joint by resistance welding to achieve stable connection and prevent misalignment or collapse during the subsequent laser welding process, ensuring the continuity and consistency of the welding path.

[0037] Step 113: After resistance welding, install the internal and external toolings of the thin-walled tube in place. After completing the resistance welding fixation, a detachable support tooling can be installed inside the thin-walled tube, and a limiting and pressing device is set outside in cooperation with the mold to ensure that the thin-walled tube maintains a stable geometric shape during the subsequent laser welding process, avoiding local collapse, wrinkles, or dimensional deviation caused by thermal deformation.

[0038] Step 114: Complete the welding of the thin-walled tube by laser welding. Use laser welding technology with high energy density and deep penetration ability to perform high-quality seal welding on the joint of the thin-walled tube along the preset trajectory. The welding process is precisely controlled by automated equipment to ensure that the weld seam is uniform and defect-free, while minimizing the heat-affected zone to the greatest extent, reducing the risk of welding deformation, and improving the mechanical strength and airtight performance of the welded joint.

[0039] Step 115: Perform vacuum leak detection after welding. Preferably, the leak rate ≤ 1×10 -8 Pa·l / s·cm 2After completing the welding of the thin-walled tube, it is placed in a dedicated vacuum detection system for overall airtightness testing. High-precision detection equipment such as a helium mass spectrometer leak detector is used to scan each point of the weld and connection parts to ensure that it has an extremely low leakage rate in an ultra-high vacuum environment, meeting the stringent requirements of the synchrotron system for the airtightness of the vacuum chamber.

[0040] Further, according to a method for processing a thin-walled vacuum chamber of the present invention, the step of fixing the thin-walled tube to the mold includes: Step 121: Place the ribs that have been cut and polished in sequence according to the positions of the rib installation grooves in the brazing mold assembly. Position and assemble the ribs that have been precisely cut according to the design dimensions and surface polished, and accurately embed them into the rib installation grooves in the brazing mold assembly at a predetermined spacing and orientation, ensuring a tight fit and accurate position between the ribs and the mold, providing a basis for the subsequent stable connection with the thin-walled tube.

[0041] Step 122: Place the thin-walled tube that has completed vacuum leak detection into the brazing mold assembly and make the ribs in close contact with the thin-walled tube. Place the thin-walled tube that has completed laser welding and passed the vacuum leak detection stably in the brazing mold assembly provided with ribs, and guide the thin-walled tube to be evenly attached to the pre-installed ribs through the mold structure, ensuring no gap contact between the two, thereby improving the reliability of the structural connection and the consistency of heat conduction during the subsequent vacuum brazing process.

[0042] Step 123: Close and fix the brazing mold assembly. The upper and lower molds can be closed and locked by hydraulic or mechanical means, so that the entire thin-walled tube and rib assembly maintains a stable three-dimensional spatial position in the mold, preventing displacement, deformation or detachment due to external force or thermal stress during the subsequent dry firing and vacuum brazing processes, and ensuring that the geometric accuracy and overall strength of the final formed structure meet the design requirements.

[0043] Such as Figure 2 、 Figure 3 and Figure 4As shown in the figure, the above-mentioned brazing die assembly preferably includes: a first brazing die 200, which has a first die space, inside which there is a reinforcing rib mounting groove 206, and around which there are bosses 202, and on the bosses 202 there are wedge-shaped positioning blocks 204; a second brazing die 300, which has a second die space opposite to the first die space, and around which there are grooves 302 corresponding to the bosses 202, and inside the grooves 302 there are wedge-shaped positioning grooves 304 corresponding to the wedge-shaped positioning blocks 204. The first die space and the second die space are used to accommodate a thin-walled vacuum chamber 100 composed of a thin-walled tube and a reinforcing rib; fastening screws 208, which are used to install and fix the first brazing die 200 and the second brazing die 300; and the materials of the first brazing die 200 and the second brazing die 300 are Al2O3. Among them, in order to show the state of the thin-walled vacuum chamber 100 in the first die space and the second die space, the Figure 2 graphic of the second brazing die 300 in [reference number] has been cropped. Compared with the traditional method, this brazing die assembly combines the technological process of pre-oxidation firing and then brazing, significantly reducing the longitudinal deformation of the thin-walled tube caused by thermal stress concentration and the risk of weld leakage, improving the product qualification rate and structural reliability, and is especially suitable for manufacturing arc-shaped bifurcated thin-walled vacuum chambers 100 with large cross-sections and high-precision requirements.

[0044] According to this brazing die assembly, specifically, the first brazing die 200 and the second brazing die 300 are respectively provided with a mutually corresponding first die space and a second die space, which are used to accommodate a vacuum chamber structure assembled by a thin-walled tube and a reinforcing rib. The first brazing die 200 is provided with a reinforcing rib mounting groove 206, which is used to accurately position and fix the position of the reinforcing rib; around it there are bosses 202, and on the bosses 202 there are wedge-shaped positioning blocks 204 installed; the second brazing die 300 is provided with matching grooves 302 and wedge-shaped positioning grooves 304 located inside the grooves 302. The first die and the second die achieve high-precision alignment through the cooperation of the wedge-shaped positioning blocks 204 and the wedge-shaped positioning grooves 304, ensuring the equidistant distribution of the reinforcing ribs on the thin-walled tube. At the same time, the cooperation of the bosses 202 and the grooves 302 also guarantees the close contact between the upper and lower surfaces of the thin-walled tube and the reinforcing rib, improving the overall structural consistency.

[0045] Furthermore, the first brazing die 200 and the second brazing die 300 are preferably made of Al2O3 ceramic material, which has the characteristics of low thermal expansion coefficient, high temperature resistance, and good chemical stability, and can effectively reduce the thermal deformation generated longitudinally by the die during the heating process, thereby improving the dimensional accuracy and form and position tolerance control (which can be stably maintained within ±0.05 mm) of the thin-walled vacuum chamber 100 after forming. The dies are preferably locked and fixed by fastening screws 208 to ensure that the entire assembled structure remains stable and unchanged during the subsequent pre-oxidation firing and vacuum brazing processes.

[0046] Further, according to a method for processing a thin-walled vacuum chamber of the present invention, the steps of subjecting the thin-walled tube to air burning treatment include: Step 131: After fixing the thin-walled tube and the mold, the whole is placed in a vacuum brazing furnace and leveled with a height gauge. Specifically, before the brazing mold assembly equipped with the thin-walled tube and the reinforcing rib is integrally placed in the vacuum brazing furnace, the mold assembly is horizontally calibrated with a high-precision height gauge to ensure that it is in a completely horizontal state in the furnace, so as to avoid local collapse or deformation of the thin-walled tube caused by uneven gravity or thermal stress during the heating process, thereby ensuring the uniformity and stability of the subsequent air burning and brazing processes.

[0047] Step 132: Heat the vacuum brazing furnace to 900 - 1000 °C. Start the vacuum brazing furnace and gradually heat it to the set temperature range of 900 - 1000 °C. This temperature range can effectively remove the residual gases, moisture, and organic pollutants on the surface of the thin-walled tube and the mold assembly, and at the same time helps to release the internal residual stress of the material, providing good metallurgical bonding conditions for the subsequent brazing process.

[0048] Step 133: Carry out heating and cooling in three stages within three hours. Specifically, the whole air burning process adopts a segmented temperature control strategy. First, it is heated from room temperature to 600 °C at a slower rate (such as 100 °C / h) for the first-stage heat preservation; then it continues to be heated to the target temperature of 900 - 1000 °C at the same or slightly higher rate to complete the second-stage heating; finally, after reaching the set temperature, it starts to gradually cool down and enters the third stage of slow cooling to about 600 °C to control the change of thermal stress and prevent the thin-walled structure from deforming or cracking due to rapid heating and cooling.

[0049] Step 134: After reaching the required temperature, start to cool with the furnace to room temperature. After completing the high-temperature air burning and cooling to 600 °C, turn off the heating system and let the mold assembly cool naturally with the furnace body to room temperature. The whole cooling process lasts for several hours to minimize the impact of thermal shock on the titanium alloy thin-walled structure and ensure the integrity and dimensional stability of the connection interface between the thin-walled tube and the reinforcing rib.

[0050] Step 135: Check whether the positions of the thin-walled tube and the reinforcing rib have changed, and conduct a vacuum leak detection. After the mold assembly is completely cooled, take it out, use a high-precision measuring tool to recheck the relative positions of the thin-walled tube and the reinforcing rib, and confirm that there is no obvious displacement or deformation; then conduct a vacuum leak detection test on the overall structure again to detect whether there is a micro-leakage and ensure that its airtightness meets the requirements of the ultra-high vacuum environment, laying a good foundation for the subsequent vacuum brazing process.

[0051] Further, according to a method for processing a thin-walled vacuum chamber of the present invention, the steps of putting it into a vacuum brazing furnace for vacuum brazing include: Step 136: Apply solder at the contact position between the thin-walled tube and the reinforcing rib. Specifically, this solder application process preferably uses a feeding machine to complete the application of HJNi-T7 solder. The solder at the contact position between the reinforcing rib and the thin-walled tube must be uniform, and the solder diameter is preferably about 3 mm. The distribution position and amount of the solder are precisely controlled by automated equipment to ensure that the solder can fully fill the joint gap during the welding process, improving the welding strength and sealing performance.

[0052] Step 137: After the thin-walled tube and the reinforcing rib are placed in the vacuum brazing furnace with the mold, level the brazing mold with a height gauge. Specifically, after the overall assembly equipped with the thin-walled tube, the reinforcing rib, and the mold is placed in the vacuum brazing furnace, a high-precision height gauge is used to level the mold to ensure that it is in an ideal horizontal state in the furnace, avoiding uneven solder flow or structural deformation caused by tilting or uneven local heating, thus ensuring uniform heating of each component and stable and reliable welding quality during the brazing process.

[0053] Step 138: Heat the vacuum brazing furnace to 1050 - 1085 °C. Start the vacuum brazing furnace and gradually increase the furnace temperature to the range of 1050 - 1085 °C according to the set program. This temperature range can make the HJNi-T7 solder fully melt and wet the surface of the base material, achieving a firm metallurgical bond between the thin-walled tube and the reinforcing rib. At the same time, maintain the vacuum degree in the furnace to prevent oxidation and impurity contamination, ensuring a dense weld structure and excellent airtightness.

[0054] Step 139: Heat up and cool down in three stages, and take it out after the temperature drops to room temperature to complete the processing. Specifically, the entire brazing process adopts a three-stage temperature control strategy: the first stage is slow heating (such as rising from room temperature to 600 °C) to remove residual gases; the second stage quickly rises to the brazing temperature (1050 - 1085 °C) and holds for a certain time to promote the full flow of the solder and complete the welding; the third stage is gradient cooling, first slowly cooling to below 600 °C and then cooling with the furnace to room temperature to reduce the influence of thermal stress and prevent deformation or cracking of the thin-walled structure. After cooling is completed, take out the mold assembly to complete the vacuum brazing process, obtaining a semi-finished arc-shaped bifurcated thin-walled vacuum chamber with a complete structure and stable dimensions, preparing for subsequent welding with the ultra-high vacuum flange.

[0055] As Figure 1The figure shows a schematic flow chart of the processing method for the thin-walled vacuum chamber in the preferred embodiment of the present application. The specific processing steps are as follows: First, perform annealing heat treatment on the ultra-thin titanium alloy plate to eliminate the internal residual stress of the material and improve its plasticity and workability. Subsequently, level the titanium alloy plate through high-precision leveling equipment, and use laser cutting technology to precisely cut out the blank with the required size and shape, ensuring that the dimensional tolerance is within ±0.05 mm. Then, carry out the processing of the thin-walled tube. Ultrasonically clean the cut titanium alloy plate to remove surface contaminants, and then roll it into a thin-walled tubular structure and preliminarily fix the seam by resistance welding. After that, cut and polish the reinforcing ribs, and embed them into the brazing die assembly according to the predetermined positions. After the thin-walled tube is in close contact with the reinforcing ribs, use hydraulic or mechanical means to close and fix the brazing die assembly to ensure the stability of each component in the subsequent process and achieve the fixation of the inner and outer molds of the thin-walled tube and the overall brazing die. Next, perform an air burning treatment on the assembled component for the ultra-thin-walled vacuum chamber to remove residual gases and organic substances and release the internal stress of the material. After the air burning is completed, evenly apply HJNi-T7 solder at the contact position between the thin-walled tube and the reinforcing ribs, and then place the component into a vacuum brazing furnace for high-temperature vacuum brazing to ensure the high strength and high tightness of the weld seam. Finally, perform a welding assembly of the brazed thin-walled vacuum chamber with a standard-specification ultra-high vacuum flange, and use high-energy beam welding technologies such as electron beam welding or laser welding to achieve high-quality welding with deep penetration and low heat-affected zone, thereby ensuring the airtightness and mechanical strength of the overall structure and meeting the technical requirements of the ultra-high vacuum environment in the synchrotron system.

[0056] Currently, in the beam extraction system of the synchrotron, if a higher-energy beam is to be extracted, usually three bending arc-type cutting magnets and one extraction dipole magnet need to cooperate to complete the beam extraction. The magnets produced require a larger wire gauge and a thicker shielding layer, and the corresponding bending arc-type vacuum chamber has a longer length during production, resulting in poor structural stability and high installation difficulty. At the same time, since the cutting magnets need to occupy a large longitudinal space, it restricts the shortening of the synchrotron circumference and is not conducive to the popularization and application of miniaturized accelerators. Therefore, in order to make the vacuum cavity in the beam extraction system meet the requirements of the new generation of miniaturized accelerators, it is particularly important to propose a bending arc-type vacuum cavity based on the beam extraction system by combining the characteristics of the cutting magnet vacuum chamber and the dipole magnet vacuum chamber.

[0057] In view of this, the present invention also provides an arc-shaped bifurcated thin-walled vacuum chamber, which is processed and formed by using the processing method of the thin-walled vacuum chamber in the above-mentioned embodiment. The arc-shaped bifurcated thin-walled vacuum chamber provided by the present invention will be described below. The arc-shaped bifurcated thin-walled vacuum chamber described below can be mutually corresponding and referred to with the thin-walled vacuum chamber processing method described above.

[0058] As Figure 5 and Figure 6As shown, the arc-shaped bifurcated thin-walled vacuum chamber 100 includes a vacuum chamber body, which is arc-shaped as a whole. Ultra-high vacuum flanges 700 are respectively arranged at both ends of the vacuum chamber body. The vacuum chamber body includes: a first vacuum chamber 400, which constitutes a part of the vacuum chamber body in the length direction. The head end of the first vacuum chamber 400 is one end of the vacuum chamber body, and one of the ultra-high vacuum flanges 700 is arranged there; a second vacuum chamber 500 and a third vacuum chamber 600 are respectively connected to the tail end of the first vacuum chamber 400. The second vacuum chamber 500 and the third vacuum chamber 600 together constitute the remaining part of the vacuum chamber body in the length direction. Another ultra-high vacuum flange 700 is jointly arranged at the tail ends of the second vacuum chamber 500 and the third vacuum chamber 600. Specifically, this arc-shaped bifurcated structure integrates the functions that need to be realized by the cutting magnet vacuum chamber and the dipole magnet vacuum chamber in the traditional beam extraction system into one, forming an integrated compact vacuum cavity, effectively reducing the longitudinal space occupation, and being beneficial to the miniaturized design and engineering application promotion of the synchrotron.

[0059] Preferably, the thickness of the thin-walled tube in the arc-shaped bifurcated thin-walled vacuum chamber 100 is preferably 0.1 - 0.2 mm. This structure significantly reduces the eddy current heating effect generated during the rapid change of the magnetic field, and improves the stability and energy efficiency of the system. At the same time, the thin-walled tube is made of titanium alloy TC4 with a higher strength limit and lighter weight, which not only meets the strength requirements of the large-section arc-shaped structure, but also adapts to the usage requirements of the miniaturized synchrotron for high stability and high reliability. In addition, the ultra-high vacuum flanges 700 used at both ends of the vacuum chamber are preferably titanium alloy flanges (the material is TC4), which have good material compatibility with the thin-walled tube body, ensuring the sealing performance and mechanical strength of the entire vacuum chamber in the ultra-high vacuum environment, and further improving the comprehensive performance and engineering practicability of the product.

[0060] Furthermore, for an arc-shaped bifurcated thin-walled vacuum chamber 100 according to the present invention, the cross-sections of the first vacuum chamber 400, the second vacuum chamber 500, and the third vacuum chamber 600 are all rectangular, which is not only convenient for manufacturing and processing, but also can ensure good structural strength and stability when each part bears the atmospheric pressure difference.

[0061] The cross-sections of the first vacuum chamber 400 and the third vacuum chamber 600 along the length direction are consistent, and the internal space dimensions of these two parts are constant, which is beneficial to simplifying the design and ensuring the stability and consistency when the beam passes through. This consistency helps to control the magnetic field uniformity on the beam path and reduce unnecessary fluctuations or interferences.

[0062] The cross-section of the second vacuum chamber 500 is trumpet-shaped along the length direction, and increases from small to large as it approaches the first vacuum chamber 400 and moves away from the first vacuum chamber 400. This gradual design can effectively guide the beam to smoothly transition from the main channel to the branch channel, avoiding beam scattering or energy loss caused by sudden changes, and is also beneficial to optimizing the magnetic field distribution and improving the extraction efficiency.

[0063] The first vacuum chamber 400 and the second vacuum chamber 500 are at the same height, which ensures that when the beam enters the curved section from the straight section, there will be no unnecessary deviation or distortion due to the height difference. The height of the third vacuum chamber 600 is less than that of the first vacuum chamber 400. Such a design can further reduce the overall size and weight of the equipment while meeting the beam transmission requirements, which is conducive to achieving the miniaturization and lightweight goals of the synchrotron. In addition, designs of different heights can better adapt to the energy requirements and physical characteristics of the beam in different areas, and enhance the flexibility and adaptability of the entire system.

[0064] Further, according to an arc-shaped bifurcated thin-walled vacuum chamber 100 of the present invention, the first vacuum chamber 400, the second vacuum chamber 500 and the third vacuum chamber 600 are respectively provided with reinforcing rib structures. The second vacuum chamber 500 includes a second thin-walled tube 502, the side of the second thin-walled tube 502 facing the third vacuum chamber 600 is a second tube side plate 508 without reinforcing rib structure, and the other three surfaces of the second thin-walled tube 502 are provided with at least one second longitudinal reinforcing rib 506 extending along the length direction of the second vacuum chamber 500, and a plurality of second transverse reinforcing ribs 504 perpendicular to the second longitudinal reinforcing rib 506. The third vacuum chamber 600 includes a third thin-walled tube 602, the side of the third thin-walled tube 602 facing the second vacuum chamber 500 is a third tube side plate 608 without reinforcing rib structure, and the other three surfaces of the third thin-walled tube 602 are provided with at least one third longitudinal reinforcing rib 606 extending along the length direction of the third vacuum chamber 600, and a plurality of third transverse reinforcing ribs 604 perpendicular to the third longitudinal reinforcing rib 606. An equidistant structural gap is formed between the second tube side plate 508 and the third tube side plate 608. This rib arrangement method takes into account the functional design of the local area while ensuring the overall structural strength of the vacuum chamber. By arranging longitudinally and transversely staggered rib structures on the other three surfaces of the second vacuum chamber 500 and the third vacuum chamber 600 except the butt joint surface, the bending and torsion resistance of each vacuum chamber when subjected to external atmospheric pressure is effectively improved, and buckling or deformation caused by local stress concentration is prevented.

[0065] Preferably, no stiffening rib structures are provided on the second tube side plate 508 and the third tube side plate 608 to ensure a flat and smooth interface between the two, facilitating subsequent assembly and avoiding problems such as weld interference and stress concentration. In addition, due to the space limitation between the second tube side plate 508 and the third tube side plate 608, no stiffening rib structure is provided. The thicknesses of the side plates of the second tube side plate 508 and the third tube side plate 608 are preferably greater than those of the remaining thin-walled tube parts, and can be specifically controlled within the range of 0.5 - 1 mm, which not only meets the beam envelope requirements but also does not affect the lightweight design of the overall structure due to excessive thickness. The structural gap formed between the second tube side plate 508 and the third tube side plate 608 is preferably designed to maintain an equal spacing of 6 - 7 mm. This structural optimization enables the arc-shaped bifurcated thin-walled vacuum chamber 100 to have higher mechanical stability and electromagnetic compatibility while achieving functional integration, and is particularly suitable for beam extraction systems in high-precision and miniaturized synchrotrons.

[0066] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "way", "specific way", or "some ways", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or way are included in at least one embodiment or way of the embodiments of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or way. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable way in any one or more embodiments or ways. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or ways described in this specification and the features of different embodiments or ways.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A processing method for a thin-walled vacuum chamber, characterized in that, Comprising: Processing the thin-walled tube; Fixing the thin-walled tube to the mold; First, subject the thin-walled tube to air burning treatment, and then place it in a vacuum brazing furnace for vacuum brazing; Weld the thin-walled tube to the ultra-high vacuum flange.

2. The processing method of the thin-walled vacuum chamber according to claim 1, characterized in that Before the step of processing the thin-walled tube, there is also a titanium alloy plate pretreatment step, specifically including: Performing annealing heat treatment on the titanium alloy plate; Leveling the titanium alloy plate and cutting it to the required size. Among them, control the dimensional tolerance of cutting the titanium alloy plate within ±0.05 mm, and leave a margin of 1-2 mm in the length direction of the titanium alloy plate.

3. The processing method of the thin-walled vacuum chamber according to claim 2, characterized in that, The step of processing the thin-walled tube includes: Ultrasonically cleaning the cut titanium alloy plate; First, perform resistance welding to fix the thin-walled tube; After resistance welding, install the internal and external toolings of the thin-walled tube in place; Complete the welding of the thin-walled tube by laser welding; Perform vacuum leak detection after welding is completed.

4. The processing method of the thin-walled vacuum chamber according to any one of claims 1 to 3, characterized in that, The step of fixing the thin-walled tube to the mold includes: Sequentially place the reinforcing ribs that have been cut and polished in place according to the positions of the reinforcing rib installation grooves in the brazing mold assembly; Place the thin-walled tube that has completed vacuum leak detection into the brazing mold assembly, and make the reinforcing ribs in close contact with the thin-walled tube; Close and fix the brazing mold assembly.

5. The processing method of the thin-walled vacuum chamber according to claim 4, characterized in that The brazing mold assembly includes: The first brazing mold, which has a first mold space, is provided with a reinforcing rib installation groove inside, and is provided with a boss around it, and a wedge-shaped positioning block is provided on the boss; The second brazing mold, which has a second mold space opposite to the first mold space, is provided with a groove corresponding to the boss around it, and a wedge-shaped positioning groove corresponding to the wedge-shaped positioning block is provided in the groove. The first mold space and the second mold space are used to accommodate the thin-walled vacuum chamber composed of the thin-walled tube and the reinforcing ribs; Fastening screws for installing and fixing the first brazing mold and the second brazing mold; The materials of the first brazing mold and the second brazing mold are Al2O3.

6. The method for machining a thin-walled vacuum chamber according to claim 4, characterized in that, The step of subjecting the thin-walled tube to air burning treatment includes: After fixing the thin-walled tube to the mold, place the whole in a vacuum brazing furnace and level it with a height gauge; Raise the temperature of the vacuum brazing furnace to 900-1000 °C; Carry out heating and cooling in three stages within three hours; After reaching the required temperature, start to cool down with the furnace to room temperature; Check whether the positions of the thin-walled tube and the reinforcing ribs have changed, and perform vacuum leak detection.

7. The processing method of the thin-walled vacuum chamber according to claim 6, wherein The step of placing in the vacuum brazing furnace for vacuum brazing includes: Apply solder at the contact position between the thin-walled tube and the reinforcing rib; After the thin-walled tube and the reinforcing rib are placed in the vacuum brazing furnace with the mold, level the brazing mold with the height gauge; Raise the temperature of the vacuum brazing furnace to 1050-1085 °C; Carry out heating and cooling in three stages, and take it out after the temperature drops to room temperature to complete the processing.

8. An arc-shaped bifurcated thin-walled vacuum chamber, characterized in that, Processed and formed by using the thin-walled vacuum chamber processing method described in any one of claims 1 to 7; The arc-shaped bifurcated thin-walled vacuum chamber includes a vacuum chamber main body, which is overall arc-shaped, and ultra-high vacuum flanges are respectively arranged at both ends of the vacuum chamber main body; The vacuum chamber main body includes: The first vacuum chamber forms a part of the main body of the vacuum chamber in the length direction. The head end of the first vacuum chamber serves as one end of the main body of the vacuum chamber, and one of the ultra-high vacuum flanges is provided there. The second vacuum chamber and the third vacuum chamber are respectively connected to the end of the first vacuum chamber. The second vacuum chamber and the third vacuum chamber together form the remaining part of the main body of the vacuum chamber in the length direction. Another ultra-high vacuum flange is jointly provided at the ends of the second vacuum chamber and the third vacuum chamber.

9. The arc-shaped bifurcated thin-walled vacuum chamber according to claim 8, characterized in that, The cross-sections of the first vacuum chamber, the second vacuum chamber and the third vacuum chamber are all rectangular. The cross-sections of the first vacuum chamber and the third vacuum chamber along the length direction remain consistent. The cross-section of the second vacuum chamber is trumpet-shaped along the length direction, gradually increasing from near the first vacuum chamber to far from the first vacuum chamber. The first vacuum chamber and the second vacuum chamber have the same height, and the height of the third vacuum chamber is less than that of the first vacuum chamber.

10. The arc-shaped bifurcated thin-walled vacuum chamber according to claim 9, characterized in that, Reinforcing rib structures are respectively provided in the first vacuum chamber, the second vacuum chamber and the third vacuum chamber, where: The second vacuum chamber includes a second thin-walled tube. One side of the second thin-walled tube facing the third vacuum chamber is a second tube side plate without a reinforcing rib structure, and at least one second longitudinal reinforcing rib extending along the length direction of the second vacuum chamber and a plurality of second transverse reinforcing ribs perpendicular to the second longitudinal reinforcing rib are provided on the remaining three surfaces of the second thin-walled tube. The third vacuum chamber includes a third thin-walled tube. One side of the third thin-walled tube facing the second vacuum chamber is a third tube side plate without a reinforcing rib structure, and at least one third longitudinal reinforcing rib extending along the length direction of the third vacuum chamber and a plurality of third transverse reinforcing ribs perpendicular to the third longitudinal reinforcing rib are provided on the remaining three surfaces of the third thin-walled tube. An equidistant structural gap is formed between the second tube side plate and the third tube side plate.

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