A forming apparatus and processing method for an L-shaped cross-section ring-shaped titanium alloy part

Abstract

This invention belongs to the field of aerospace sheet metal parts processing technology, and discloses a forming device and processing method for an "L"-shaped cross-section ring-shaped titanium alloy parts. The forming device for the "L"-shaped cross-section ring-shaped titanium alloy parts includes a bending die, a knocking die, and a heat treatment fixture. The processing method for the "L"-shaped cross-section ring-shaped titanium alloy parts replaces the traditional process flow of "milling blanking – manual forming – heat treatment – ​​finishing" with "milling blanking – bending forming – manual forming – stabilization heat treatment – ​​milling the outline". This invention solves the problems of large manual workload, difficulty in heat treatment deformation repair, large surface errors, and poor surface quality in the forming process of large titanium alloy ring-shaped profile parts. In the newly designed process flow, the part processing is mainly carried out using a bending machine, resulting in a high degree of mechanization in part manufacturing, high processing efficiency, and good quality.

Description

Technical Field

[0001] This invention relates to the field of sheet metal parts processing technology for aircraft, and in particular to a forming device and processing method for an "L"-shaped cross-section annular titanium alloy parts. Background Technology

[0002] There is an "L"-shaped cross-section annular component in aircraft structures. These components are made of titanium alloy, are large in size (up to 1300mm in diameter, only 1.6mm thick), and have a maximum "L" width of 27mm. They are typically installed in the rear fuselage, with the annular section connecting to the outer skin to support it. Therefore, the component's shape is closely related to the aircraft's aerodynamic shape, requiring high manufacturing precision. The traditional manufacturing method involves machining "L"-shaped titanium alloy profiles. First, a blank in its straightened state is milled, and then the part's shape is formed manually. The forming process primarily uses tools such as hammers and aluminum hammers to strike the surface of the blank, repeatedly "releasing" and "retracting" the material to force it to flow and bend into shape. This process is prone to cracks and wrinkles, making it difficult to guarantee surface accuracy. Furthermore, titanium alloy is a high-strength alloy, making it difficult to machine and exhibiting significant springback during forming. Repeated finishing and stabilization heat treatment are necessary, but the part may deform again during stabilization heat treatment, requiring further finishing. Therefore, the production of this type of part is characterized by high processing difficulty, high labor intensity, difficulty in repairing deformed parts, and poor surface quality due to repeated repairs, which affects fatigue strength. Summary of the Invention

[0003] The purpose of this invention is to provide a forming device and processing method for L-shaped cross-section annular titanium alloy parts. The processing method employs a newly designed bending die for auxiliary forming and a heat treatment fixture to prevent part deformation during heat treatment. It replaces the previous process of "milling – manual forming – heat treatment – ​​finishing" with a new process flow of "milling blanking – bending forming – manual forming – stabilization heat treatment – ​​milling the outline". The tooling used in this invention can solve problems such as high manual workload, difficulty in repairing deformation during heat treatment, and poor surface quality in the forming of large titanium alloy annular parts, thereby improving the accuracy of part shape, improving surface quality, and reducing labor intensity. This technical solution is scalable and can be applied to the manufacturing of complex, high-curvature titanium alloy sheet metal parts.

[0004] To achieve the above objectives, the technical solution of the present invention is: a forming device for an "L"-shaped cross-section annular titanium alloy parts, comprising a bending die, a knocking die, and a heat treatment fixture;

[0005] The bending die includes a body 1 and a pressure plate 4, both of which are annular and have the same shape as the inner surface of the part. The height of the body 1 is greater than the bending height of the part, and the outer dimensions of the pressure plate 4 are greater than the outer dimensions of the body 1. Tool holes a2 and fixture holes 3 are respectively provided at corresponding positions on the body 1 and the pressure plate 4, which are used to align and connect the body 1 and the pressure plate 4 and to connect the heat treatment fixture, respectively.

[0006] The inspection mold includes a mold body I7 and a mold body II8; the working surface of mold body I7 is the same as the outer surface of the web of the part, and the working surface of mold body II8 is the same as the outer surface of the bent edge of the part; mold body I7 can support mold body II8; both mold body I7 and mold body II8 are provided with tool holes b9 for alignment and connection; both mold body I7 and mold body II8 are marked with part edge lines 11, which are used as the standard for cutting the edge lines of the part and for inspecting the external dimensions of the part.

[0007] The heat treatment fixture includes a base assembly 12, a side plate assembly 13, a pressure plate assembly 14, and a clamping assembly 15. The base assembly 12 serves as a support, and its outer side is connected to the pressure plate assembly 14 and the side plate assembly 13 in sequence by cylindrical pins 17. The three are clamped together by the clamping assembly 15. The side surface of the pressure plate assembly 14 is the same as the inner surface of the bent edge of the part, and the bottom surface is the same as the inner surface of the web of the part. The side surface of the side plate assembly 13 is the same as the outer surface of the bent edge of the part.

[0008] The height of the body 1 is 20mm greater than the bending height of the part, and the outer dimensions of the pressure plate 4 are 5mm greater than the outer dimensions of the body 1.

[0009] Considering the large springback during the bending process, which may result in the surface not fitting the tooling after bending, a springback angle can be created in the tooling by simulating the part forming process or by conducting experiments. The springback angle can be obtained from the simulation experiment, and the surface of the jig body 1 can be adjusted according to the springback angle.

[0010] A processing method for an "L"-shaped cross-section ring-shaped titanium alloy part replaces the traditional process flow of "milling blanking - manual forming - heat treatment - finishing" with "milling blanking - stretch bending forming - manual forming - stabilization heat treatment - milling the outer shape".

[0011] The processing method for the aforementioned "L"-shaped cross-section annular titanium alloy part specifically includes the following steps:

[0012] Step 1: Milling and blanking;

[0013] Milling uses the unfolded digit model of the part as the basis for processing, and mills out the blank in the unfolded state for subsequent forming; during milling, clamping allowance is added to both ends of the part; the unfolded digit model is unfolded according to the three-dimensional data of the part, the cross-sectional shape of the part remains unchanged, and the arc is straightened into a straight line segment according to the sheet metal unfolding theory.

[0014] Step 2: Bending and shaping;

[0015] Fix the bending die; select the jaws according to the cross-sectional shape of the part, clamp both ends of the blank in the jaws, with a clamping distance of not less than 100mm at both ends, and the center of the blank should be against the bending center of the bending die; adjust the tension value, the blank moves with the jaws, the jaws and the bending die produce relative displacement, and the blank bends until it is completely pressed against the bending die; after completing the above steps, unload the tension and take out the semi-finished part along the direction perpendicular to the bending die surface; Step 3: Manual forming;

[0016] Place the semi-finished part into the inspection mold, and use tools to adjust the parts that do not fit the inspection mold until the gap between the semi-finished part and the inspection mold meets the requirements.

[0017] Step 4: Stabilization heat treatment;

[0018] Remove the clamping assembly 15 from the heat treatment fixture, separate the pressure plate assembly 14, and fix the side plate assembly 13 to the base assembly 12; after placing the part formed in step three, install the pressure plate assembly 14, and completely fix the side plate assembly 13, pressure plate assembly 14, and base assembly 12 through the clamping assembly 15; place the heat treatment fixture containing the part into a vacuum furnace for stabilization heat treatment for a set time to eliminate residual stress; after the part is annealed, it is cooled with argon gas at a cooling rate of 2℃ / min~4℃ / min, and the part is cooled with the vacuum furnace to below 280℃ and then air-cooled; after the temperature returns to room temperature, loosen the clamping assembly 15, separate the pressure plate assembly 14, and unload the part;

[0019] Step 5: Mill the outline;

[0020] Based on the edge line 11 of the part on the inspection mold, scribing is performed on the part, and the excess part is removed by milling.

[0021] The milling is performed using laser cutting with a laser power of 2500W, a cutting speed of 8m / min, and a gas pressure of 10bar.

[0022] The stabilization heat treatment is carried out by vacuum annealing in a vacuum furnace with a vacuum pressure not exceeding 0.0666 Pa. The heating is performed by cold wall radiant electric heating at a temperature of 750°C and a temperature rise rate of 2°C / min to 4°C / min.

[0023] The beneficial effects of this invention are as follows: By replacing the traditional process of "milling blanking – manual forming – heat treatment – ​​finishing" with a process flow of "milling blanking – stretch bending – manual forming – stabilization heat treatment – ​​milling outline," and using a newly designed stretch bending die to assist in forming the part's shape, and a heat treatment fixture to prevent deformation during heat treatment, this invention solves the problems of large manual workload, difficulty in repairing deformation during heat treatment, large surface errors, and poor surface quality in the forming of large titanium alloy ring-shaped profiles. In the newly designed process flow, the part processing is mainly carried out using a stretch bending machine, resulting in a high degree of mechanization in part manufacturing, high processing efficiency, and better quality. Attached Figure Description

[0024] Figure 1 This is a typical part outline drawing;

[0025] Figure 2(a) is a structural diagram of the tension bending die;

[0026] Figure 2(b) is the AA cross-sectional view of Figure 2(a);

[0027] Figure 3(a) shows the structure of the knock-in test mold;

[0028] Figure 3(b) is a BB cross-sectional view of Figure 3(a);

[0029] Figure 4 This is a three-dimensional structural diagram of the heat treatment fixture;

[0030] Figure 5(a) is a two-dimensional structural diagram of the heat treatment fixture;

[0031] Figure 5(b) is a CC cross-sectional view of Figure 5(a).

[0032] In the diagram: 1. Body; 2. Tool hole a; 3. Fixture hole; 4. Pressure plate; 5. Mold closing screw; 6. Lifting eye; 7. Body I; 8. Body II; 9. Tool hole b; 10. Mold closing pin; 11. Part edge line; 12. Base assembly; 13. Side plate assembly; 14. Pressure plate assembly; 15. Clamping assembly; 16. Screw; 17. Cylindrical pin; 18. Lifting eye screw. Detailed Implementation

[0033] This invention is widely applicable, employing a stretch bending machine to form large-curvature profile parts and using a heat treatment fixture to control deformation during the heat treatment process. It can be extended to various materials (such as titanium alloys and aluminum alloys) and large-curvature extruded profile parts (T-shaped, L-shaped, Z-shaped sections, etc.). For L-shaped, Z-shaped, and other cross-sectional sheet bending parts, the sheet metal can first be processed into L-shaped, Z-shaped, or other cross-sections using a bending method, and then stretched and bent to the final part shape. Compared with traditional sheet bending parts using rubber bladder hydraulic forming, this method results in less springback, higher shape accuracy, and no surface wrinkles or other defects.

[0034] The specific scheme for the forming device and processing method of the "L"-shaped cross-section annular titanium alloy part is described below:

[0035] This forming device and processing method mainly consists of milling blanking, stretch bending forming, manual forming, stabilization heat treatment, and milling of the outer shape. It can realize the manufacturing of "L" shaped cross-section ring titanium alloy parts, reduce labor intensity, improve production efficiency and surface quality. The specific steps are briefly introduced below with examples.

[0036] As shown in Figures 2 and 3 Figure 4 Figure 5 shows the machining method for an "L"-shaped cross-section annular titanium alloy part. This machining method is based on a bending die, a hammering die, and a heat treatment fixture. The bending die includes a die body 1, tool hole a2, fixture hole 3, pressure plate 4, die-closing screw 5, and lifting eye 6. The hammering die includes a die body I 7, a die body II 8, tool hole b9, die-closing pin 10, and part edge line 11. The heat treatment fixture includes a base assembly 12, side plate assembly 13, pressure plate assembly 14, clamping assembly 15, screws 16, cylindrical pins 17, and lifting eye screws 18.

[0037] The aforementioned bending die has a body 1 whose surface is designed according to the inner surface of the part, and its height is 20mm greater than the bending edge height of the part. Three tool holes a2 are machined at appropriate positions on the body for alignment and connection between the pressure plate 4 and the body 1. To facilitate the installation and fixation of the die on the bending machine, 4-φ135mm through holes are milled at corresponding positions on the body and pressure plate for fixing the die to the bending die platform using clamps. The pressure plate 4 has a similar overall shape to the body 1, but its outer dimensions are slightly larger, generally by 5mm, and it is used to press the blank against the body during bending to prevent vertical movement of the blank. Mold-closing screws 5 align and tighten the body 1 and pressure plate 4. Lifting rings 6 are installed on the body and pressure plate respectively for lifting and transporting the die. For complex sheet metal parts, considering the large springback during the bending process, which may result in the surface not fitting the tooling after bending, the springback angle can be created in the tooling by simulating the part forming process or by conducting experiments (i.e., making local adjustments to the surface of the jig structure 1), thereby compensating for the tooling surface and reducing the impact of springback on the bending of the part.

[0038] The aforementioned inspection mold has a structural body I7, designed according to the outer shape of the web surface of the part, used to ensure the outer shape of the web surface of the part during forming and to support body II8. Structural body II8 has a working surface designed according to the outer shape of the bent edge of the part, used to ensure the outer dimensions of the bent edge of the part during forming. Body I7 and body II8 are aligned through tool holes b9 and fixed with mold-closing pins 10. Body I7 and body II8 maintain their relative positions during forming, jointly ensuring the outer dimensions of the part. The edge lines 11 of the part are respectively marked on body I7 and body II8, used for cutting the edge lines of the part after forming and for inspecting the outer dimensions of the part.

[0039] The heat treatment fixture has a base assembly 12 that serves as the main frame, supporting the entire fixture. Welded ribs elevate the base to a certain height, facilitating the installation and disassembly of the clamping assembly 15. The side plate assembly 13 and pressure plate assembly 14 both employ a segmented assembly structure. Their sides are designed according to the outer and inner surfaces of the bent edges of the parts, respectively, while the bottom surface of the pressure plate assembly 14 is designed according to the inner surface of the web of the part. The side plate assembly and pressure plate assembly can be aligned with the base assembly using cylindrical pins 17 and secured with screws 16. The clamping assembly 15 ensures that the parts do not deform during heat treatment within the structure formed by the side plate assembly, pressure plate assembly, and base assembly, thus achieving stable heat treatment of the parts. Eye bolts 18 are installed at appropriate positions on the base assembly and clamping plate assembly for mold lifting and handling. Considering that the fixture needs to undergo heat treatment along with the parts, TA15 is selected as the main manufacturing material for the fixture, and 1Cr18Ni9Ti is selected for the screws and eye bolts.

[0040] A method for machining an L-shaped cross-section annular titanium alloy part includes the following steps:

[0041] The first step is milling and cutting the material.

[0042] Milling is performed using laser cutting to produce an "L"-shaped blank in a straightened state for subsequent forming. The milling process utilizes a unfolded digital model of the part as the medium. Considering the added bending process in subsequent forming, a 300mm allowance is added to each end of the part for clamping during milling. The unfolded digital model unfolds based on the part's three-dimensional data, maintaining the "L" shape of the cross-section while straightening the arc into a straight segment according to sheet metal unfolding theory. Laser cutting is used with a laser power of 2500W, a cutting speed of 8m / min, and a gas pressure of 10bar. First, the surface of the blank to be cut is coated with No. 45 anti-wear hydraulic oil for protection. It is then fixed to the laser cutting machine platform using a laser cutting fixture. The cutting program is called, and the origin is set on the blank according to the part's shape and the program's cutting start point. A trial cut is then performed, running the cutting program without laser application to verify the smoothness and accuracy of the cutting path. If the trial run is successful, the part is cut according to the cutting program. During the cutting process, the cutting gas pressure is checked to prevent incomplete cutting. After cutting, the fixture is unloaded, and the blank is removed.

[0043] The second step is bending and shaping.

[0044] The tooling used for stretch bending is called a "stretch bending die," which consists of the following structure: die body 1, tool holes a2, clamping holes 3, pressure plate 4, clamping screws 5, and lifting rings 6. The stretch bending die is used to bend milled "L"-shaped straightened blanks into a "ring" shape. The die body 1 is designed according to the inner surface of the part, with a height 20mm greater than the bending edge height. Three tool holes a2 are machined at appropriate positions on the die body for alignment and connection between the pressure plate and the die body. To facilitate the installation and fixation of the die on the stretch bending machine, four φ135mm through holes are milled at corresponding positions on the die body and pressure plate for fixing the die to the stretch bending die platform using clamps. The pressure plate 4 has a similar overall shape to the die body, but its outer dimensions are slightly larger (generally 5mm is sufficient). It is used to press the blank against the die body during the stretch bending process, preventing vertical movement of the blank. The clamping screws 5 align and tighten the die body 1 and pressure plate 4. Lifting rings 6 are installed on the jig and pressure plate respectively for mold lifting and handling. For complex sheet metal parts, considering the large springback during the bending process, the surface may not fit the tooling after bending. The springback angle can be created in the tooling by simulating the part forming process or by experimentation (i.e., local adjustment of the jig structure 1), thereby compensating for the tooling surface and reducing the impact of springback on the bending forming of the part.

[0045] First, the bending die is fixed to the bending machine platform using fixing pins. Then, an "L"-shaped jaw is selected based on the profile's cross-sectional shape, clamping both ends of the blank within the jaws with a clamping distance of at least 100mm. The center of the blank is pressed against the bending center of the bending die. The tension is adjusted, and the blank moves with the jaws, creating a relative displacement between the jaws and the bending die, bending the blank until it is completely flush with the bending die. After completing these steps, the tension is released, and the part (semi-finished product) is removed perpendicular to the bending die's profile. Compared to purely manual forming, this method uses mechanical operation, resulting in parts without hammer marks or other defects, lower operator workload, and higher finished product quality. For complex sheet metal parts, considering the significant springback during bending, which can lead to misalignment between the profile and the tooling after bending, a springback angle can be created in the tooling by simulating the part forming process or through testing. This compensates for the springback on the tooling profile, reducing the impact of springback on the bending process.

[0046] The third step is hand-shaping.

[0047] The tooling used for manual forming is a "knock-in test die," which consists of the following structure: die body I7, die body II8, tool hole b9, mold closing pin 10, and part edge line 11. The knock-in test die is used to shape the drawn part (semi-finished product) to the final shape required by the design drawings and can also be used for part inspection. Die body I7 is designed according to the outer surface of the part's web, ensuring the shape of the web surface during forming and supporting die body II8. Die body II8 has its working surface designed according to the outer surface of the part's bend, ensuring the outer dimensions of the bend during forming. Die bodies I7 and II8 are aligned through tool hole b9 and fixed with mold closing pin 10. Die bodies I7 and II8 maintain their relative position during forming, jointly ensuring the part's surface dimensions. The part edge line 11 is marked on die bodies I7 and II8 respectively, used for cutting the part's edge line after forming and for inspecting the part's outer dimensions.

[0048] The part (semi-finished product) is placed into the "test mold". Using tools such as a hammer, the parts that do not fit the "test mold" are manually adjusted until the gap between the part and the "test mold" meets the design requirements. After the part is formed by stretching and bending, the surface of the part basically meets the requirements, so the workload of this process is relatively small.

[0049] The fourth step is stabilization heat treatment.

[0050] The stabilization heat treatment is carried out by vacuum annealing, with the aim of eliminating internal stress after forming, improving the plasticity and structural stability of the material, and thus obtaining better overall performance. The tooling used in this process is a "heat treatment fixture", which consists of the following structure: base assembly 12, side plate assembly 13, pressure plate assembly 14, clamping assembly 15, screws 16, cylindrical pins 17, and eye bolts 18.

[0051] The aforementioned "heat treatment fixture" is placed in the heat treatment equipment along with the part to ensure that the titanium alloy part maintains its shape during heat treatment. The base assembly 12 serves as the main frame of the fixture, supporting the entire fixture and using welded ribs to elevate the base to a certain height, facilitating the installation and disassembly of the clamping assembly 15. Both the side plate assembly 13 and the pressure plate assembly 14 adopt a segmented assembly structure, with their sides designed according to the outer and inner surfaces of the part's curved edges, respectively. The bottom surface of the pressure plate assembly 14 is designed according to the inner surface of the part's web. The side plate assembly and pressure plate assembly can be aligned with the base assembly using cylindrical pins 17 and secured with screws 16. The clamping assembly 15 ensures that the part does not deform within the structure formed by the side plate assembly, pressure plate assembly, and base assembly during heat treatment, thereby achieving the purpose of stabilizing the part during heat treatment. Eye bolts 18 are installed at appropriate positions on the base assembly and clamping plate assembly for mold lifting and handling. Considering that the fixture needs to be heat-treated along with the parts, TA15 is selected as the main material for manufacturing the fixture, and 1Cr18Ni9Ti is selected for the screws and eye bolts.

[0052] The stabilization heat treatment is carried out using vacuum annealing in a vacuum furnace. The vacuum pressure is generally no greater than 0.0666 Pa, and heating is achieved using cold-wall radiant electric heating at approximately 750°C with a temperature rise rate of 2°C / min to 4°C / min. Once the vacuum furnace is operational, the clamping assembly 15 of the heat treatment fixture is removed, and the pressure plate assembly 14 is separated. The side plate assembly 13 is fixed to the base assembly 12 using screws 16. The part formed in step three is then placed in the furnace, and the pressure plate assembly 14 is installed. The clamping assembly 15 completely secures the side plate assembly, pressure plate assembly, and base assembly, thus completely fixing the part in the heat treatment fixture. The heat treatment fixture containing the part is then placed in the vacuum furnace for stabilization heat treatment to eliminate residual stress, with a holding time of 2 hours. The presence of the fixture significantly reduces warping under weight load and heat treatment stress, preventing deformation of the part. After annealing, the parts are cooled with argon gas at a rate of 2°C / min to 4°C / min. The parts are cooled in the furnace to below 280°C and then removed for air cooling. Once the temperature returns to room temperature, the clamping assembly 15 is released, the pressure plate assembly 14 is separated, and the parts are unloaded.

[0053] The fifth step is milling the outer shape.

[0054] The milling process is done manually. Its purpose is to remove the bending and clamping allowance left by the milling and to improve the surface roughness of the machined area by using tools such as files and sandpaper, so that the dimensions of the part meet the design drawing requirements.

[0055] Based on the edge lines of the part on the "inspection mold", scribing is performed on the part, and excess parts are milled away. Since this process is simple, it can be done manually. After cutting, the edges are sanded using files, sandpaper, and other tools to ensure the surface roughness meets the design requirements.

[0056] After completing the above steps, the final physical part is obtained.

Claims

1. A forming apparatus for an "L"-shaped cross-section annular titanium alloy parts, characterized in that, This includes bending dies, inspection dies, and heat treatment fixtures; The bending die includes a body (1) and a pressure plate (4), both of which are annular and have the same shape as the inner surface of the part; the height of the body (1) is greater than the bending height of the part, and the outer dimensions of the pressure plate (4) are greater than the outer dimensions of the body (1); tool holes a (2) and fixture holes (3) are respectively provided at corresponding positions on the body (1) and the pressure plate (4), which are used to align and connect the body (1) and the pressure plate (4) and to connect the heat treatment fixture, respectively; The inspection mold includes body I (7) and body II (8); the working surface of body I (7) is the same as the outer surface of the web of the part, and the working surface of body II (8) is the same as the outer surface of the bent edge of the part; both body I (7) and body II (8) are provided with tool holes b (9) for alignment and connection; both body I (7) and body II (8) are marked with part edge lines (11) for use as the standard for cutting the edge lines of the part and for inspecting the external dimensions of the part; The heat treatment fixture includes a base assembly (12), a side plate assembly (13), a pressure plate assembly (14), and a clamping assembly (15). The base assembly (12) serves as a support, and the pressure plate assembly (14) and the side plate assembly (13) are connected in sequence on its outer side by cylindrical pins (17). The three are clamped together by the clamping assembly (15). The side surface of the pressure plate assembly (14) is the same as the inner surface of the bent edge of the part, and the bottom surface is the same as the inner surface of the web of the part. The side surface of the side plate assembly (13) is the same as the outer surface of the bent edge of the part.

2. The forming apparatus for an "L"-shaped cross-section annular titanium alloy parts according to claim 1, characterized in that, The height of the body (1) is 20mm greater than the bending height of the part, and the outer dimensions of the pressure plate (4) are 5mm greater than the outer dimensions of the body (1).

3. The forming apparatus for an "L"-shaped cross-section annular titanium alloy parts according to claim 1 or 2, characterized in that, The springback angle is obtained from the simulation test, and the tire body (1) profile is adjusted according to the springback angle.

4. A method for machining an "L"-shaped cross-section annular titanium alloy part, characterized in that, The traditional process flow of "milling blanking - manual forming - heat treatment - trimming" is replaced with "milling blanking - stretch bending forming - manual forming - stabilization heat treatment - milling the outer shape"; the specific steps are as follows: Step 1: Milling and blanking; Milling uses the unfolded digit model of the part as the basis for processing, and mills out the blank in the unfolded state for subsequent forming; during milling, a clamping allowance is added to both ends of the part; The unfolded digital model is unfolded based on the three-dimensional data of the part, while the cross-sectional shape of the part remains unchanged. The arc is straightened into a straight line segment according to the sheet metal unfolding theory. Step 2: Bending and shaping; Fix the bending die; select the jaws according to the cross-sectional shape of the part, clamp both ends of the blank in the jaws, with a clamping distance of not less than 100mm at both ends, and the center of the blank should be against the bending center of the bending die; adjust the tension value, the blank moves with the jaws, the jaws and the bending die produce relative displacement, the blank bends until it is completely pressed against the bending die; after completing the above steps, unload the tension and take out the semi-finished part along the direction perpendicular to the bending die surface; Step 3: Manual forming; Place the semi-finished part into the inspection mold, and use tools to adjust the parts that do not fit the inspection mold until the gap between the semi-finished part and the inspection mold meets the requirements. Step 4: Stabilization heat treatment; Remove the clamping assembly (15) of the heat treatment fixture, separate the pressure plate assembly (14), and fix the side plate assembly (13) to the base assembly (12); after placing the part formed in step three, install the pressure plate assembly (14), and completely fix the side plate assembly (13), pressure plate assembly (14), and base assembly (12) through the clamping assembly (15); place the heat treatment fixture containing the part into a vacuum furnace for stabilization heat treatment for a set time to eliminate residual stress; after the part is annealed, it is cooled with argon gas at a cooling rate of 2℃ / min to 4℃ / min, and the part is cooled with the vacuum furnace to below 280℃ and then air-cooled; after the temperature returns to room temperature, loosen the clamping assembly (15), separate the pressure plate assembly (14), and unload the part; Step 5: Mill the outline; Based on the edge line (11) of the part on the inspection mold, scribing is performed on the part, and the excess part is removed by milling.

5. The processing method for the "L"-shaped cross-section annular titanium alloy part according to claim 4, characterized in that, The milling is performed using laser cutting with a laser power of 2500W, a cutting speed of 8m / min, and a gas pressure of 10bar.

6. The method for processing an "L"-shaped cross-section annular titanium alloy part according to claim 4 or 5, characterized in that, The stabilization heat treatment is carried out by vacuum annealing in a vacuum furnace with a vacuum pressure not exceeding 0.0666 Pa. The heating is performed by cold wall radiant electric heating at a temperature of 750°C and a temperature rise rate of 2°C / min to 4°C / min.

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