Machining methods for long-journey centrifugal impellers for aero engines

Abstract

This invention relates to a method for machining a long-journey centrifugal impeller for an aero-engine, belonging to the field of centrifugal impeller machining. Through detailed pre-welding preparation processes, hot-press assembly, electron beam welding, and subsequent finishing and special treatment steps, the high precision and reliability of the impeller assembly are ensured. This method not only minimizes the impeller's mass while maintaining sufficient strength, helping to reduce the inertia and fuel consumption of the entire engine system, but also improves the blade surface finish through a rigorous surface treatment process, thereby reducing frictional losses during operation. In particular, the use of a double-disc clamping welding fixture for electron beam welding effectively ensures the precision and stability of the long-journey centrifugal impeller during machining, improving the quality of the final product. Furthermore, X-ray inspection and vacuum stress relief treatment of the welded impeller assembly, followed by post-weld finishing, further enhance the impeller's durability and safety.

Description

Technical Field

[0001] This invention relates to the field of centrifugal impeller machining technology, and in particular to a machining method for a long-journey centrifugal impeller for aero-engines. Background Technology

[0002] Centrifugal impellers, as a core component of aero-engines, function to compress and accelerate gas through high-speed rotation, providing a stable and high-pressure airflow to the combustion chamber, thereby ensuring the engine's efficient and smooth operation. Since the early days of the aviation industry in the 20th century, centrifugal impeller technology has grown and developed alongside it. Early designs were relatively simple, and limited by the materials science and technology available at the time, these initial attempts, while laying the foundation, fell far short of meeting the demands of modern aviation. With the advancement of technology, especially the advent of the jet aircraft era after World War II, increasingly stringent performance requirements for aircraft have prompted engineers to continuously improve the design and manufacturing processes of centrifugal impellers. Today, thanks to the application of advanced computational fluid dynamics (CFD) analysis tools and the development of new materials such as high-strength, lightweight materials like titanium alloys, modern centrifugal impellers have not only made leaps and bounds in structural complexity but have also achieved significant successes in improving aerodynamic efficiency, reducing weight, and enhancing durability.

[0003] However, facing increasing global environmental awareness and stringent emission standards, how to further improve the efficiency of centrifugal impellers, reduce energy consumption, and minimize environmental impact has become a significant challenge in contemporary aerospace engineering. To address these challenges, researchers and engineers are dedicated to exploring more optimized design concepts and technologies. For example, minimizing impeller mass while ensuring sufficient strength reduces the inertia and fuel consumption of the entire engine system; developing new machining methods to improve blade surface finish and reduce friction losses; and employing advanced clamping methods to ensure the precision and stability of long-jersey centrifugal impellers during machining are all current research priorities. Furthermore, considering the special status of the aero-engine as the "heart" of an aircraft, any minor design flaw or manufacturing error can affect flight safety. Therefore, in-depth research into the manufacturing process of centrifugal impellers, especially the treatment of critical components such as long-jersey sections, is crucial for ensuring the safe and reliable operation of the engine and the entire aircraft. Summary of the Invention

[0004] The purpose of this invention is to provide a method for machining a long-journey centrifugal impeller for an aero-engine, so as to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for machining a long-journey centrifugal impeller for an aero-engine, wherein the long-journey centrifugal impeller is assembled by electron beam welding of a front journal and a centrifugal impeller, and the method includes:

[0007] S1. Perform a pre-welding preparation process on the front journal. The pre-welding preparation process for the front journal includes at least material preparation, rough machining, stress relief, fine machining, fitting, marking, intermediate inspection, fluorescence inspection, cleaning, final inspection, and packaging and warehousing to obtain the front journal part to be welded.

[0008] S2. Perform a pre-welding preparation process on the centrifugal impeller. The pre-welding preparation process for the centrifugal impeller includes at least material preparation, rough turning, milling of angular grooves, rough milling of blade profile and flow channel, stress relief, fine turning, expansion and repair of angular grooves, fine milling of blade profile and flow channel, clamping and repair, marking, intermediate inspection, fluorescent inspection, cleaning, final inspection, and packaging and warehousing to obtain the centrifugal impeller part to be welded.

[0009] S3. The front journal to be welded and the centrifugal impeller to be welded are hot-pressed together. The fit between the front journal to be welded and the centrifugal impeller to be welded is an interference fit, so as to obtain the assembled impeller assembly.

[0010] S4. The assembled impeller assembly is placed into a double-disc clamping welding fixture for electron beam welding to obtain the welded impeller assembly.

[0011] S5. Perform X-ray inspection and vacuum stress relief on the welded impeller assembly. Perform post-weld finishing on the stress-relieved welded impeller assembly. The post-weld finishing includes at least datum repair, precision turning, and grinding to obtain the finished impeller assembly.

[0012] S6. The finished impeller assembly is placed into a keyway machining fixture for involute spline milling, end face groove machining, and circumferential hole machining to obtain the long-journey centrifugal impeller.

[0013] In one possible implementation, steps S1 and S2 are as follows:

[0014] The welding bevels of the front journal component to be welded and the centrifugal impeller component to be welded are set as a locking bottom structure. The root of the locking bottom structure is provided with a venting groove 1-2mm wide, and a shrinkage allowance of 0.1-0.2mm is reserved at the welding bevel.

[0015] In one possible implementation, in step S3:

[0016] After heating the front journal part to be welded to 80-110℃ and holding it at that temperature for 30 minutes, it is then hot-pressed together with the centrifugal impeller part to be welded, ensuring that the gap at the assembly point is no greater than 0.03mm.

[0017] The interference fit between the journal component to be welded and the centrifugal impeller component to be welded is 0.02-0.04 mm.

[0018] In one possible implementation, prior to step S4, the following steps are also included:

[0019] By simulating the parts to be welded using welding test pieces, the test pieces are dissected and their metallographic structure, properties, surface and internal quality are examined to determine whether they fully meet the requirements, so as to determine the welding parameters.

[0020] In one possible implementation, in step S4:

[0021] The double-disc clamping welding fixture includes a welding positioning disc, an anti-rotation disc, an internal hexagon screw, a screw rod, a first pressure plate, a disc-shaped elastic washer, and a first nut. The welding positioning disc is connected to the welding equipment. The anti-rotation disc is installed on the side of the welding positioning disc connected to the welding equipment via the internal hexagon screw. The screw rod is inserted into the center hole of the welding positioning disc. The assembled impeller assembly is sleeved on the screw rod. The first pressure plate and the disc-shaped elastic washer are sequentially inserted into the side of the screw rod away from the welding positioning disc, and then tightened and fixed by the first nut.

[0022] In one possible implementation, in step S5:

[0023] The vacuum stress relief temperature for the welded impeller assembly is 500℃±10℃, and it is held at this temperature for 4h±10min before furnace cooling.

[0024] In one possible implementation, in step S6:

[0025] The keyway machining fixture includes a connecting seat, a mandrel, a second pressure plate, and a second nut. The connecting seat is connected to the machining equipment. The mandrel is inserted into the center hole of the connecting seat. The precision-machined impeller assembly is sleeved on the mandrel. The second pressure plate is inserted into the side of the mandrel away from the connecting seat and tightened by the second nut.

[0026] In one possible implementation, the blanks for both the front journal and the centrifugal impeller are made of titanium alloy TC11.

[0027] The beneficial effects of the technical solution provided by this invention include at least the following:

[0028] The machining method for long-journey centrifugal impellers in aero-engines provided by this technical solution ensures high precision and reliability of the impeller assembly through detailed pre-welding preparation processes, hot-press assembly, electron beam welding, and subsequent finishing and special treatment steps. This method not only minimizes the impeller's mass while ensuring sufficient strength, helping to reduce the inertia and fuel consumption of the entire engine system, but also improves the blade's surface finish through a rigorous surface treatment process, thereby reducing frictional losses during operation. In particular, the use of a double-disc clamping welding fixture for electron beam welding effectively ensures the precision and stability of the long-journey centrifugal impeller during machining, improving the quality of the final product. Furthermore, X-ray inspection and vacuum stress relief treatment of the welded impeller assembly, followed by post-weld finishing, further enhance the impeller's durability and safety. This high-quality machining process plays a crucial role in improving the operating efficiency and extending the service life of aero-engines, and also contributes to promoting technological progress and sustainable development in my country's and the global aviation industry. Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0030] Figure 1 A flowchart illustrating a method for machining a long-journey centrifugal impeller for an aero-engine, provided by an exemplary embodiment of the present invention, is shown.

[0031] Figure 2 A detailed process flow diagram of a method for machining a long-journey centrifugal impeller for an aero-engine, provided by an exemplary embodiment of the present invention, is shown.

[0032] Figure 3 The diagram shows the pre-welding state of the front journal of a processing method for a long journal centrifugal impeller of an aero-engine according to an exemplary embodiment of the present invention.

[0033] Figure 4 The diagram shows the pre-welding state of a centrifugal impeller, according to a processing method for a long-journey centrifugal impeller for an aero-engine provided by an exemplary embodiment of the present invention.

[0034] Figure 5 The diagram shows an electron beam welding state of a method for processing a long-journey centrifugal impeller for an aero-engine according to an exemplary embodiment of the present invention.

[0035] Figure 6 The diagram shows a double-disc clamping welding fixture for a method of machining a long-journey centrifugal impeller for an aero-engine, provided by an exemplary embodiment of the present invention.

[0036] Figure 7 This diagram illustrates a reference datum for the finishing of a welded impeller assembly during the final machining process, as part of a machining method for a long-journey centrifugal impeller for an aero-engine according to an exemplary embodiment of the present invention.

[0037] Figure 8 The diagram shows a finished impeller assembly based on a machining method for a long-journey centrifugal impeller for an aero-engine, provided by an exemplary embodiment of the present invention.

[0038] Figure 9 The diagram shows a keyway machining fixture for a machining method of a long-journey centrifugal impeller for an aero-engine, provided by an exemplary embodiment of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] Figure 1 This invention illustrates a flowchart of a method for machining a long-journey centrifugal impeller for an aero-engine, according to an exemplary embodiment of the present invention. Figure 2 This diagram illustrates a detailed process flow of a method for manufacturing a long-judge centrifugal impeller for an aero-engine, according to an exemplary embodiment of the present invention. The long-judge centrifugal impeller is manufactured by combining a front journal and a centrifugal impeller via electron beam welding. The method includes:

[0042] Step S1: Perform pre-welding preparation procedures on the front axle journal. The pre-welding preparation procedures for the front axle journal include at least material preparation, rough machining, stress relief, fine machining, fitting, marking, intermediate inspection, fluorescent inspection, cleaning, final inspection, and packaging and warehousing to obtain the front axle journal part to be welded.

[0043] In one example Figure 3 The diagram shows the pre-welding state of the front journal of a centrifugal impeller for a long journal of an aero-engine, provided by an exemplary embodiment of the present invention. Except for the end face and inner hole marked by the thick solid line in the diagram, which have been machined to the final state, a 1mm allowance is reserved on each side in the other positions.

[0044] Specifically, the pre-welding preparation process for the front axle journal aims to machine it to near its final dimensions, leaving only a 1mm allowance on one side for final finishing in certain critical areas. Rough turning removes most of the rough allowance, bringing the workpiece close to its final shape and dimensions. Stress-relief annealing eliminates internal stresses generated during cold working, preventing deformation or cracking during subsequent processing or use. Finish turning ensures the workpiece surface achieves high precision, providing a good foundation for subsequent assembly.

[0045] Step S2: Perform pre-welding preparation procedures for the centrifugal impeller. The pre-welding preparation procedures for the centrifugal impeller include at least material preparation, rough turning, milling of angular grooves, rough milling of blade profile and flow channel, stress relief, fine turning, expansion and repair of angular grooves, fine milling of blade profile and flow channel, clamping and repair, marking, intermediate inspection, fluorescent inspection, cleaning, final inspection, and packaging and warehousing to obtain the centrifugal impeller part to be welded.

[0046] In the pre-welding preparation processes of steps S1 and S2 above, in order to ensure axial and radial runout and coaxiality after welding, and to enable self-centering during assembly, the welding bevels of the journal component to be welded and the centrifugal impeller component to be welded are set as locking bottom structures. Figure 5 The diagram illustrates an electron beam welding process for a long-journey centrifugal impeller for an aero-engine, according to an exemplary embodiment of the present invention. The root of the locking structure has a 1-2 mm wide venting groove, and a 0.1-0.2 mm shrinkage allowance is reserved at the welding bevel. This design not only facilitates self-centering but also effectively vents gases generated during welding, preventing porosity defects and thus improving weld quality.

[0047] In one example, the blank bars for the front journal and centrifugal impeller of this application are both titanium alloy TC11 / GJB2218A. This material has excellent mechanical properties and corrosion resistance, and is suitable for manufacturing high-performance aero-engine components.

[0048] In one example Figure 4 The diagram shows the pre-welding state of a centrifugal impeller, which is a processing method for a long-journey centrifugal impeller of an aero-engine according to an exemplary embodiment of the present invention. Except for the end face, inner hole, and blade flow channel marked by the thick solid line in the diagram, which have been processed to the final state, a 1mm allowance is reserved on each side in the other positions.

[0049] Specifically, the pre-welding preparation process for the centrifugal impeller includes steps similar to those for the front journal, but also includes specific operations such as milling angular grooves, rough milling of the blade profile and flow channel, widening and refining the angular grooves, and finishing milling of the blade profile and flow channel. This is because the centrifugal impeller structure is more complex, requiring fine machining of the blade shape and its internal flow channel to ensure its aerodynamic performance. Similarly, after completing the above machining, except for the key areas marked in the diagram which have reached their final state, a 1mm allowance is reserved on each side for subsequent finishing adjustments.

[0050] Step S3: Hot press assembly of the front journal part to be welded and the centrifugal impeller part to be welded. The mating stop of the front journal part to be welded and the centrifugal impeller part to be welded is an interference fit, resulting in the assembled impeller assembly.

[0051] In this embodiment, the journal component to be welded is heated to 80-110°C and kept at that temperature for 30 minutes before being hot-pressed and assembled with the centrifugal impeller component to be welded, ensuring that the gap at the assembly point is no greater than 0.03 mm; the interference fit between the journal component to be welded and the centrifugal impeller component to be welded is 0.02-0.04 mm.

[0052] Specifically, the front journal component to be welded is heated to 80-110℃ and held at that temperature for 30 minutes before being assembled with the centrifugal impeller component. This process utilizes the thermal expansion and contraction characteristics of materials, causing the front journal component to expand under heating, thus enabling it to smoothly mate with the centrifugal impeller component to achieve an interference fit. As the temperature gradually returns to room temperature, the front journal component contracts, forming a tight mechanical connection, ensuring that the gap at the assembly is no greater than 0.03mm, while maintaining an interference fit of 0.02-0.04mm. This hot-press assembly method has several significant advantages: First, it can achieve a tight fit between parts without applying excessive external pressure, avoiding damage or deformation problems that may be caused by forced assembly; second, by strictly controlling the heating temperature and holding time, it can be ensured that the workpiece will not undergo metallographic changes due to excessively high temperatures, affecting its mechanical properties; in addition, the use of an interference fit not only improves assembly accuracy but also enhances the fatigue resistance and sealing of the interface, which is particularly important for aero engines subjected to high-speed and high-pressure environments.

[0053] To ensure the success rate and quality of hot-press assembly, parameters such as heating temperature, holding time, and cooling rate must be precisely monitored during the operation. For example, heating within the range of 80-110℃ specified in this embodiment, and maintaining sufficient time to allow the heat to be evenly distributed across the entire component, allows the front journal component to expand fully without damaging the material structure. After assembly, as the temperature drops, the front journal component naturally contracts and tightly integrates with the centrifugal impeller component, forming a robust whole—the assembled impeller assembly. This method not only effectively prevents loosening but also reduces vibration transmission, thereby improving the stability and efficiency of the entire engine system.

[0054] Step S4: The assembled impeller assembly is placed into a double-disc clamping welding fixture for electron beam welding to obtain the welded impeller assembly.

[0055] It is worth mentioning that, prior to step S4, the process includes: simulating the part to be welded using a welding test piece, dissecting the test piece, and checking whether its metallographic structure, properties, surface, and internal quality fully meet the requirements to determine the welding parameters. This step is crucial for ensuring welding quality and the reliability of subsequent products because it allows engineers to identify and resolve potential problems in advance, thereby avoiding unnecessary rework or scrap.

[0056] In the embodiments of this application, Figure 6 This diagram illustrates a double-disc clamping welding fixture for processing a long-journey centrifugal impeller for an aero-engine, according to an exemplary embodiment of the present invention. The double-disc clamping welding fixture includes a welding positioning disc 1, an anti-rotation disc 2, hexagon socket screws 7, a screw rod 4, a first pressure plate 3, a disc-shaped elastic washer 5, and a first nut 6. The welding positioning disc 1 is connected to the welding equipment. The anti-rotation disc 2 is installed on the side of the welding positioning disc 1 connected to the welding equipment via the hexagon socket screws 7. The screw rod 4 is inserted into the center hole of the welding positioning disc 1. After assembly, the impeller assembly is fitted onto the screw rod 4. The first pressure plate 3 and the disc-shaped elastic washer 5 are sequentially inserted into the side of the screw rod 4 away from the welding positioning disc 1, and then tightened and fixed by the first nut 6. This double-disc clamping welding fixture ensures that the welding process will not loosen due to weld shrinkage, the clamping force remains constant, and it is unaffected by thermal expansion and contraction. The assembled impeller assembly must be installed in a double-disc clamping welding fixture and welded within 8 hours. This time limit is to ensure that the material properties and process conditions are optimal during welding, avoiding changes in material properties or interference from environmental factors due to excessive waiting time, which could affect weld quality. Electron beam welding is a high-precision, low-heat-input welding method that can achieve deep penetration in a short time while minimizing the thermal impact on the surrounding area, making it ideal for welding difficult-to-weld materials such as titanium alloys.

[0057] Step S5: Perform X-ray inspection and vacuum stress relief on the welded impeller assembly. After stress relief, perform post-weld finishing on the welded impeller assembly. Post-weld finishing includes at least repairing the reference (see...). Figure 7 ), precision machining (see) Figure 8 The impeller assembly is obtained through grinding and finishing.

[0058] In this embodiment, the vacuum stress relief temperature for the welded impeller assembly is 500℃±10℃, and it is held at this temperature for 4h±10min before furnace cooling.

[0059] Specifically, X-ray inspection is used to assess the presence of internal defects in the welded area, such as cracks, porosity, or lack of fusion. This is an indispensable part of ensuring weld quality. X-ray non-destructive testing can visually display the internal structure of the weld, helping engineers to promptly identify and resolve potential quality issues, thereby preventing defective products from entering the next process. Next is vacuum stress relief treatment, a heat treatment process performed on the welded impeller assembly under specific conditions (e.g., temperature 500℃±10℃, holding for 4 hours±10 minutes, followed by furnace cooling) to eliminate residual stress generated during welding. Uneven heating and cooling rates during welding can generate internal stresses in the workpiece, which may lead to deformation or fatigue fracture during long-term use. Therefore, by controlling the heating and cooling rates, these adverse effects can be effectively reduced or eliminated without affecting the material's mechanical properties. Performing this process in a vacuum also prevents oxidation and other surface contamination, preserving the material's original physical properties. After vacuum stress relief, the welded impeller assembly undergoes post-weld finishing. Finishing includes at least three main steps: datum repair, precision turning, and grinding. The purpose of datum repair is to redefine or restore critical dimension reference points to ensure that subsequent machining operations can achieve the required accuracy; finish turning further improves the surface quality and dimensional accuracy of the parts, making the shape closer to the design value; and grinding, as the final step, not only obtains an extremely smooth surface finish, but also corrects small errors introduced by previous processes, ensuring that all geometric parameters meet strict standards.

[0060] Step S6: After finishing, the impeller assembly is placed into the keyway machining fixture for involute spline milling, end face groove machining, and circumferential hole machining to obtain a long-journey centrifugal impeller.

[0061] In the embodiments of this application, Figure 9This diagram illustrates a keyway machining fixture for a machining method of a long-journey centrifugal impeller for an aero-engine, provided by an exemplary embodiment of the present invention. The keyway machining fixture includes a connecting seat 8, a mandrel 9, a second pressure plate 10, and a second nut 11. The connecting seat 8 is connected to the machining equipment. The mandrel 9 is inserted into the center hole of the connecting seat 8, ensuring the stability and concentricity of the entire machining process. After precision machining, the impeller assembly is fitted onto the mandrel 9. The second pressure plate 10 is inserted into the side of the mandrel 9 away from the connecting seat 8 and tightened by the second nut 11. This design ensures that the workpiece will not shift or loosen during the entire machining process, thereby improving machining accuracy. Milling of the involute splines on both sides, end face grooves, and circumferential holes can be completed in a single clamping operation, significantly reducing clamping time. Using such a keyway machining fixture and technical solution not only meets the requirements of high precision but also effectively shortens the manufacturing cycle and reduces production costs. This is particularly important for the aero-engine manufacturing industry, which pursues high performance and high quality standards. By optimizing fixture design and machining processes, manufacturers can improve productivity and enhance market competitiveness while ensuring product quality.

[0062] In summary, the machining method for long-journey centrifugal impellers for aero-engines provided by this technical solution ensures high precision and reliability of the impeller assembly through detailed pre-welding preparation processes, hot-press assembly, electron beam welding, and subsequent finishing and special treatment steps. This method not only minimizes the impeller's mass while ensuring sufficient strength, helping to reduce the inertia and fuel consumption of the entire engine system, but also improves the blade's surface finish through a rigorous surface treatment process, thereby reducing frictional losses during operation. In particular, the use of a double-disc clamping welding fixture for electron beam welding effectively ensures the precision and stability of the long-journey centrifugal impeller during machining, improving the quality of the final product. Furthermore, X-ray inspection and vacuum stress relief treatment of the welded impeller assembly, followed by post-weld finishing, further enhance the impeller's durability and safety. This high-quality machining process plays a crucial role in improving the operating efficiency and extending the service life of aero-engines, and also contributes to promoting technological progress and sustainable development in my country's and the global aviation industry.

[0063] It is understood that the specific examples in this document are only intended to help those skilled in the art better understand this disclosure, and are not intended to limit the scope of the invention.

[0064] It is understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of this disclosure.

[0065] It is understood that the various implementation methods described in this specification can be implemented individually or in combination, and this disclosure does not limit them.

[0066] Unless otherwise stated, all technical and scientific terms used in this disclosure have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this specification. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0067] The above description is merely a specific embodiment of this specification, but the scope of protection of this invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this specification should be included within the scope of protection of this specification. Therefore, the scope of protection of this invention should be determined by the scope of the claims.

Claims

1. A method for machining a long-journey centrifugal impeller for an aero-engine, characterized in that, The long-journal centrifugal impeller is manufactured by combining a front journal and a centrifugal impeller through electron beam welding. The method includes: S1. Perform a pre-welding preparation process on the front journal. The pre-welding preparation process for the front journal includes at least material preparation, rough machining, stress relief, fine machining, fitting, marking, intermediate inspection, fluorescence inspection, cleaning, final inspection, and packaging and warehousing to obtain the front journal part to be welded. S2. Perform a pre-welding preparation process on the centrifugal impeller. The pre-welding preparation process for the centrifugal impeller includes at least material preparation, rough turning, milling of angular grooves, rough milling of blade profile and flow channel, stress relief, fine turning, expansion and repair of angular grooves, fine milling of blade profile and flow channel, clamping and repair, marking, intermediate inspection, fluorescent inspection, cleaning, final inspection, and packaging and warehousing to obtain the centrifugal impeller part to be welded. S3. The front journal to be welded and the centrifugal impeller to be welded are hot-pressed together. The fit between the front journal to be welded and the centrifugal impeller to be welded is an interference fit, so as to obtain the assembled impeller assembly. S4. The assembled impeller assembly is placed into a double-disc clamping welding fixture for electron beam welding to obtain the welded impeller assembly. S5. Perform X-ray inspection and vacuum stress relief on the welded impeller assembly. Perform post-weld finishing on the stress-relieved welded impeller assembly. The post-weld finishing includes at least datum repair, precision turning, and grinding to obtain the finished impeller assembly. S6. The finished impeller assembly is placed into a keyway machining fixture for involute spline milling, end face groove machining, and circumferential hole machining to obtain the long-journey centrifugal impeller. In step S3: The journal component to be welded is heated to 80-110℃ and held for 30 minutes before being hot-pressed with the centrifugal impeller component to be welded, ensuring that the gap at the assembly point is no greater than 0.03mm; the interference fit between the journal component to be welded and the centrifugal impeller component to be welded is 0.02-0.04mm.

2. The machining method for a long-journey centrifugal impeller for an aero-engine according to claim 1, characterized in that, In steps S1 and S2: The welding bevels of the front journal component to be welded and the centrifugal impeller component to be welded are set as a locking bottom structure. The root of the locking bottom structure is provided with a venting groove 1-2mm wide, and a shrinkage allowance of 0.1-0.2mm is reserved at the welding bevel.

3. The machining method for a long-journey centrifugal impeller for an aero-engine according to claim 1, characterized in that, Before step S4, the method further includes: By simulating the parts to be welded using welding test pieces, the test pieces are dissected and their metallographic structure, properties, surface and internal quality are examined to determine whether they fully meet the requirements, so as to determine the welding parameters.

4. The machining method for a long-journey centrifugal impeller for an aero-engine according to claim 1, characterized in that, In step S4: The double-disc clamping welding fixture includes a welding positioning disc, an anti-rotation disc, an internal hexagon screw, a screw rod, a first pressure plate, a disc-shaped elastic washer, and a first nut. The welding positioning disc is connected to the welding equipment. The anti-rotation disc is installed on the side of the welding positioning disc connected to the welding equipment via the internal hexagon screw. The screw rod is inserted into the center hole of the welding positioning disc. The assembled impeller assembly is sleeved on the screw rod. The first pressure plate and the disc-shaped elastic washer are sequentially inserted into the side of the screw rod away from the welding positioning disc, and then tightened and fixed by the first nut.

5. The machining method for a long-journey centrifugal impeller for an aero-engine according to claim 1, characterized in that, In step S5: The vacuum stress relief temperature for the welded impeller assembly is 500℃±10℃, and it is held at this temperature for 4h±10min before furnace cooling.

6. The machining method for a long-journey centrifugal impeller for an aero-engine according to claim 1, characterized in that, In step S6: The keyway machining fixture includes a connecting seat, a mandrel, a second pressure plate, and a second nut. The connecting seat is connected to the machining equipment. The mandrel is inserted into the center hole of the connecting seat. The precision-machined impeller assembly is sleeved on the mandrel. The second pressure plate is inserted into the side of the mandrel away from the connecting seat and tightened by the second nut.

7. The machining method for a long-journey centrifugal impeller for an aero-engine according to claim 1, characterized in that, The blanks for both the front journal and the centrifugal impeller are made of titanium alloy TC11.

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