A device for preventing quenching deformation of thin-walled deep cylindrical parts.

Abstract

This utility model relates to a device for preventing quenching deformation of thin-walled deep cylindrical parts, comprising an upper die mechanism and a lower die mechanism. The lower die mechanism includes a fixed base and a stretching die. A through hole is formed in the middle of the fixed base, and the stretching die is fixedly disposed in the through hole. The upper die mechanism includes a driving end and a supporting end. The driving end is connected to a power output mechanism for realizing the up-and-down reciprocating motion of the upper die mechanism. A forming cavity is provided in the middle of the stretching die, and the supporting end is used to extend into the forming cavity, so that the workpiece is located between the stretching die and the supporting end, allowing the sidewall of the workpiece to be stretched and shaped after heat treatment. The lower die mechanism also includes a scraping assembly disposed in the through hole of the fixed base for disassembling the stretched and shaped workpiece. This device, by stretching and shaping the thin-walled deep cylindrical part after quenching and tempering, eliminates quenching deformation of the workpiece, improves manufacturing accuracy, and greatly saves clamping and disassembly time.

Description

Technical Field

[0001] This utility model relates to the field of heat treatment deformation control technology, specifically to a device for preventing quenching deformation of thin-walled deep cylindrical parts. Background Technology

[0002] Currently, in response to such Figure 1 When quenching the thin-walled deep cylindrical parts shown, the commonly used process in the industry is to use a special tooling fixture during the quenching process of the finished part. The specific operation is as follows: before the workpiece enters the quenching stage, the thin-walled deep cylindrical part is pre-installed in the tooling fixture. The aim is to use the constraint effect of the tooling fixture to rigidly fix and limit the workpiece during the quenching process, thereby suppressing its deformation (as shown in Figure 2). However, practice has shown that this tooling constraint scheme has the following significant technical defects in controlling the quenching deformation of thin-walled deep cylindrical parts: (1) The tooling clamping and disassembly process is inefficient and difficult to operate. When using the fixture shown in Figure 1 to suppress the deformation of thin-walled deep cylindrical parts, the assembly clearance between the fixture and the workpiece must be strictly controlled within a very small tolerance range to ensure the effectiveness of clamping and positioning and the deformation suppression effect. This high-precision clearance requirement directly leads to repeated adjustments and calibrations during the fixture clamping process, consuming a lot of time. Furthermore, during the disassembly stage, due to the significant non-uniformity of the internal stress distribution of the workpiece after quenching, the deformation of different parts of the workpiece varies randomly, further exacerbating the jamming phenomenon between the fixture and the workpiece. This significantly increases the labor intensity of the disassembly operation and severely restricts the improvement of production efficiency.

[0003] (2) There is a risk of secondary deformation of the workpiece after the tooling is removed, resulting in poor accuracy and stability. After the quenching process is completed and the tooling fixtures are removed, the residual stress inside the workpiece will undergo a redistribution and rebalancing process. During this process, thin-walled deep cylindrical parts are prone to secondary micro-deformation due to the loss of tooling constraints. This subsequent deformation directly negates the deformation control effect achieved by the initial tooling constraints, making it difficult for the final form and position accuracy of the workpiece to meet design requirements. This is especially true for high-precision thin-walled deep cylindrical parts, where the stability of dimensional accuracy and shape tolerances cannot be effectively guaranteed, seriously affecting the assembly performance and service life of the product. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a device for preventing quenching deformation of thin-walled deep cylindrical parts. By using this device to stretch and shape the thin-walled deep cylindrical parts after quenching and tempering, quenching deformation can be eliminated, manufacturing accuracy can be improved, and clamping and disassembly time can be greatly reduced.

[0005] The objective of this utility model is achieved through the following solution: A device for preventing deformation of thin-walled deep cylindrical parts during quenching includes an upper die mechanism and a lower die mechanism; The lower die mechanism includes a fixed base and a stretching die. A through hole is opened in the middle of the fixed base, and the stretching die is fixedly installed in the through hole. The upper die mechanism includes a driving end and a supporting end. The driving end is connected to a power output mechanism to realize the up-and-down reciprocating motion of the upper die mechanism. A shaping cavity is provided in the middle of the stretching die. The supporting end of the upper die mechanism is used to extend into the shaping cavity, so that the workpiece is located between the stretching die and the supporting end, allowing the side wall of the workpiece to be stretched after the workpiece is heat treated, thus completing the shaping of the workpiece. The lower mold mechanism also includes a scraping component disposed in the through hole of the fixed seat, which is used to smoothly separate the workpiece from the upper mold mechanism after the workpiece has been shaped.

[0006] The lower die mechanism also includes a scraping assembly disposed in the through hole of the fixed seat, used to disassemble the workpiece after stretching and shaping.

[0007] Preferably, one end of the through hole of the fixing seat is provided with a first stepped surface, and the stretching die is engaged in the through hole so that the bottom surface of the stretching die abuts against the first stepped surface. A pressure plate is also fixedly connected to the top of the fixing seat, and the pressure plate abuts against the top of the stretching die, thereby limiting and fixing the stretching die.

[0008] Preferably, the stretching die includes a guide die, a concave die for stretching the workpiece, and a shaping die, wherein the guide die, the concave die, and the shaping die are stacked from top to bottom.

[0009] Preferably, the width of the working zone of the lower die is ≤5mm.

[0010] Preferably, the width of the mold working zone of the shaping mold is in the range of 10 to 20 mm.

[0011] Preferably, the upper die mechanism includes a mounting base and a punch. The punch includes a positioning shoulder and a forming stamping part. One end of the mounting base is fixedly connected to the power output mechanism, and the positioning shoulder is snapped and fixed to the other end of the mounting base, so that the forming stamping part and the forming cavity of the stretching die are coaxially arranged.

[0012] Preferably, the forming and stamping part is provided with a first blind hole along the axial direction, and the forming and stamping part is provided with a second blind hole along the radial direction, and the first blind hole and the second blind hole are connected.

[0013] Preferably, the scraping assembly is disposed below the stretching die. The scraping assembly includes a base and a scraping ring formed by multiple scraping petals. The base is snapped and fixed between the second step surface of the through hole and the bottom surface of the stretching die, and the outer periphery of the base is in close contact with the inner wall of the through hole. The outer periphery of the scraping ring is elastically connected to the inner wall of the base through multiple circumferentially distributed elastic elements.

[0014] Preferably, the inner circumferential dimension of the lower die is smaller than the inner circumferential dimension of the forming die.

[0015] The beneficial effects of this utility model are as follows: A device for preventing deformation of thin-walled deep cylindrical parts during quenching includes an upper die mechanism and a lower die mechanism; The lower die mechanism includes a fixed base and a stretching die. A through hole is opened in the middle of the fixed base, and the stretching die is fixedly installed in the through hole. The upper die mechanism includes a driving end and a supporting end. The driving end is connected to a power output mechanism to realize the up-and-down reciprocating motion of the upper die mechanism. A shaping cavity is provided in the middle of the stretching die. The supporting end of the upper die mechanism is used to extend into the shaping cavity, so that the workpiece is located between the stretching die and the supporting end, allowing the side wall of the workpiece to be stretched after the workpiece is heat treated, thus completing the shaping of the workpiece. The lower mold mechanism also includes a scraping component disposed in the through hole of the fixed seat, which is used to smoothly separate the workpiece from the upper mold mechanism after the workpiece has been shaped.

[0016] This invention relates to a device for stretching and shaping thin-walled deep cylindrical parts after quenching and cooling. The device clamps and compresses the workpiece between a stretching die and a support end, thus achieving stretching and shaping. This process induces plastic deformation in the workpiece, effectively eliminating the problem of severe deformation of the thin-walled cylinder itself caused by direct heat treatment of the finished workpiece. Furthermore, the device is easy to operate, effectively avoiding the cumbersome clamping and disassembly processes of traditional methods, and is more suitable for mass production of deep cylindrical parts.

[0017] Preferably, one end of the through hole of the fixing seat is provided with a first stepped surface, and the stretching die is engaged in the through hole so that the bottom surface of the stretching die abuts against the first stepped surface. A pressure plate is also fixedly connected to the top of the fixing seat, and the pressure plate abuts against the top of the stretching die, thereby limiting and fixing the stretching die.

[0018] Preferably, the stretching die includes a guide die, a concave die for stretching the workpiece, and a shaping die, wherein the guide die, the concave die, and the shaping die are stacked from top to bottom.

[0019] The stretching die of this invention is snapped into the through hole of the fixed base and abuts against the stretching die by the first stepped surface and the pressure plate, forming radial and axial positioning constraints on the stretching die. This effectively prevents it from shifting during operation and avoids affecting the workpiece forming accuracy due to loosening of the stacked layers. Furthermore, by adopting a combined structure of stacked layers, this invention allows for flexible adjustment of the parameters of each module according to different process requirements and facilitates the individual replacement of vulnerable parts, reducing maintenance costs.

[0020] Preferably, the width of the working zone of the lower die is ≤5mm.

[0021] The concave die of this invention can stretch the thin wall of a workpiece (thin-walled deep cylindrical part) to produce plastic deformation. At the same time, the working zone of the concave die is designed to be narrow, which can effectively reduce frictional resistance and thus avoid excessive wear of the workpiece material and overheating of the die.

[0022] Preferably, the width of the mold working zone of the shaping mold is in the range of 10 to 20 mm.

[0023] This forming die can shape a stretched workpiece, causing it to undergo slight plastic deformation. By setting the working band width of the forming die to be slightly larger, the workpiece can be fully shaped, thus ensuring the accuracy of the finished product.

[0024] Preferably, the upper die mechanism includes a mounting base and a punch. The punch includes a positioning shoulder and a forming stamping part. One end of the mounting base is fixedly connected to the power output mechanism, and the positioning shoulder is snapped and fixed to the other end of the mounting base, so that the forming stamping part and the forming cavity of the stretching die are coaxially arranged.

[0025] This invention ensures that the force exerted by the punch on the workpiece is accurately transmitted along the axial direction by keeping the forming stamping part and the forming cavity of the stretching die coaxially, thus avoiding workpiece deformation or machining accuracy deviation caused by extra torque due to eccentricity and effectively improving the consistency of the forming effect.

[0026] Preferably, the forming and stamping part is provided with a first blind hole along the axial direction, and the forming and stamping part is provided with a second blind hole along the radial direction, and the first blind hole and the second blind hole are connected.

[0027] This invention creates an internal airflow channel by setting a first blind hole and a second blind hole in the forming stamping part. During the workpiece stretching and forming process, the trapped air between the forming stamping part and the workpiece is effectively discharged, avoiding the impact of air pressure blockage on the fit accuracy of the workpiece, and thus affecting the finished product accuracy of the workpiece.

[0028] Preferably, the scraping assembly is disposed below the stretching die. The scraping assembly includes a base and a scraping ring formed by multiple scraping petals. The base is snapped and fixed between the second step surface of the through hole and the bottom surface of the stretching die, and the outer periphery of the base is in close contact with the inner wall of the through hole. The outer periphery of the scraping ring is elastically connected to the inner wall of the base through multiple circumferentially distributed elastic elements.

[0029] This invention places the scraper assembly below the stretching die, and its scraper ring is elastically connected to the base through multiple circumferentially distributed elastic elements. When the workpiece is shaped and stretched, and the upper die mechanism rises, the restoring force of the elastic elements can drive the scraper ring to apply force evenly along the outer periphery of the workpiece, so as to smoothly peel the workpiece from the stretching die, which significantly improves the unloading efficiency.

[0030] Preferably, the inner circumferential dimension of the lower die is smaller than the inner circumferential dimension of the forming die.

[0031] In this invention, when the workpiece passes through a die with a smaller inner circumference, a larger radial pressure can be applied to the side wall of the workpiece, causing it to undergo preliminary plastic tensile deformation, thereby achieving preliminary correction of the deformation amount after quenching. When it passes through a forming die with a larger inner circumference, a secondary plastic micro-deformation adjustment can be performed on the workpiece. By gradually releasing internal stress and correcting dimensional deviations, the workpiece can ultimately achieve the dimensional and positional accuracy required by the design.

[0032] Definitions: Mold working zone: The mold working zone is the key contact surface in the mold that directly contacts the blank (i.e., thin-walled deep cylindrical parts) and guides its deformation and shaping. Attached Figure Description

[0033] Figure 1 Figure (a) shows the thin-walled deep cylindrical part before stretching and shaping, and Figure (b) shows the thin-walled deep cylindrical part after stretching and shaping. Figure 2 This is a schematic diagram of the assembly of traditional thin-walled deep cylindrical parts and fixtures. Figure 3 This is a schematic diagram of the device structure of this utility model. Detailed Implementation

[0034] like Figures 1 to 3 As shown, a device for preventing deformation of thin-walled deep cylindrical parts during quenching includes an upper die mechanism and a lower die mechanism. The lower die mechanism includes a fixed base 1 and a stretching die 2. The stretching die 2 includes a guide die 201 for guiding the workpiece 3 (i.e., the blank of a thin-walled deep cylindrical part) when it is placed into the die, a lower die 202 for stretching the workpiece 3 to cause plastic deformation, and a shaping die 203 for shaping the stretched thin-walled deep cylindrical part to cause micro-plastic deformation. The guide die 201, lower die 202, and shaping die 203 are stacked sequentially in the through hole in the middle of the fixed base 1. In actual use, the inner circumference of the guide die 201 is the largest, while the inner circumference of the lower die 202 is smaller than that of the shaping die 203, so as to facilitate better plastic deformation of the workpiece. In this embodiment, the working band width of the lower die 202 is ≤5mm to avoid excessive material wear or die overheating; the working band width of the shaping die 203 is between 10 and 20mm to ensure sufficient shaping.

[0035] Specifically, a first stepped surface 4 is provided inside the through hole. The stretching die 2 is snapped into the through hole, so that the bottom surface of the shaping die 203 abuts against the first stepped surface 4, and the outer periphery of the stretching die 2 abuts against the inner wall of the through hole. A pressure plate 5 is provided on the top of the fixing base 1. The pressure plate 5 is fixedly connected to the top of the fixing base 1 by screws, so that the top of the guide die 201 abuts against one end of the pressure plate 5, and the stretching die 2 is completely fixed in the through hole, so as to ensure that the die will not loosen during the operation of the device, thereby affecting the accuracy of the finished product.

[0036] The upper die mechanism includes a drive end and a support end. The drive end is a mounting base 6, and the support end is a punch 7. The punch 7 includes a positioning shoulder 701 and a forming stamping part 702. The positioning shoulder 701 is snapped and fixed to one end of the mounting base 6. Specifically, the mounting base 6 includes a base plate 601, an upper die base 603, and a fixing member 602 that is detachably and fixedly connected to the upper die base 603. One end of the base plate 601 and the upper die base 603 are fixedly connected together by bolts. A snap-fit ​​through hole is provided in the middle of the upper die base 603. The inner circumference of the snap-fit ​​through hole is adapted to the outer circumference of the positioning shoulder 701, and the depth of the snap-fit ​​through hole is adapted to the axial length of the positioning shoulder 701. Specifically, a first through hole is provided in the middle of the fixing member 602. The inner circumference of the first through hole is smaller than the outer circumference of the positioning shoulder 701, so that the punch 7 can be firmly snapped and fixed on the mounting base 6.

[0037] The other end of the mounting base 6 (i.e., the other end face of the base 601) is fixedly connected to the power output mechanism to realize the up-and-down reciprocating motion of the upper mold mechanism. In this embodiment, the power output mechanism is a hydraulic press. The middle part of the stretching die 2 is provided with a forming cavity 8 that is adapted to the thin-walled shape of the thin-walled deep cylindrical part. The above-mentioned forming stamping part 702 and the forming cavity 8 of the stretching die 2 are coaxially arranged.

[0038] A first blind hole 7021 is provided along the axial direction at the end of the forming and stamping part 702, and a second blind hole 7022 is provided along the radial direction. The first blind hole 7021 and the second blind hole 7022 are connected. In this embodiment, the distance between the second blind hole 7022 and the end of the forming and stamping part 702 is greater than the thin-wall height of the thin-walled deep cylindrical part to be processed, so as to facilitate better gas discharge.

[0039] The lower die mechanism also includes a scraping assembly (i.e., a workpiece disassembly assembly) disposed within the through hole of the fixed base 1, used to disassemble the stretched and shaped workpiece 3. This scraping assembly is located below the stretching die 2 and consists of a base 9 and a scraping ring 10 formed by multiple scraping blades. In this embodiment, the scraping ring 10 is formed by three scraping blades, and the outer periphery of the scraping ring 10 is elastically connected to the inner wall of the base 9 through multiple circumferentially distributed elastic elements (such as springs).

[0040] More specifically, the lower die mechanism also includes a lower die mounting base 11, which is fixedly connected to the fixed base 1 by bolts. The fixed base 1 has a first shaping block 12 and a second shaping block 13 inside its through hole. The upper surface of the first shaping block 12 is a second stepped surface. The base 9 is snapped and fixed between the second stepped surface of the through hole and the bottom surface of the stretching die 2, and the outer periphery of the base 9 fits tightly against the inner wall of the through hole to ensure the stability of the scraping assembly during operation. Vent holes are provided on the first shaping block 12 and the fixed base 1 to expel gas generated during the shaping process, preventing gas retention from affecting the shaping accuracy and surface quality of the workpiece.

[0041] In this embodiment, the base 601, the first shaping block 12, the second shaping block 13, and the lower mold mounting base 11 all function as electrode plates, generating a magnetic field when energized during the shaping process. The electromagnetic force generated by this magnetic field can apply an external force of specific direction and magnitude to the workpiece, thereby assisting in the shaping process. Especially for precision parts requiring high control over deformation amount and direction, this invention enables fine-tuning of the workpiece shape without direct contact with the workpiece surface, effectively avoiding surface damage that may result from traditional mechanical shaping and further ensuring the processing quality of the workpiece.

[0042] The following is a specific embodiment using the above-mentioned device: 1) Preparation of blanks for thin-walled deep cylindrical parts. In this embodiment, 30CrMnSiA bar stock is prepared into blanks as shown in the figure through multiple stamping processes. Figure 1 (a) The blank of a thin-walled deep cylindrical part with specified dimensions for the process has the following dimensional requirements: h≈320mm; φd≈62.73mm; t=1.2mm.

[0043] The blanks for thin-walled deep cylindrical parts undergo heat treatment (quenching and tempering). The blanks are placed in a vacuum heat treatment furnace and held at 860℃ for 1.5 hours. They are then transferred to a quenching oil bath and cooled for a period to complete the martensitic transformation. Finally, they are placed in a tempering furnace and held at 440℃ for 3 hours to complete the tempered troostite formation. This yields deep cylindrical blanks with a tensile strength ≥1200 MPa and a hardness of 40–45 HRC.

[0044] The blanks of heat-treated thin-walled deep cylindrical parts undergo phosphating and saponification treatment. The specific operation process is as follows: After heat treatment, the deep cylindrical parts are placed in a solution containing a high-efficiency metal cleaning agent (total alkalinity 150-400 points, temperature ≥60℃) for 10 minutes to remove oil. Then, they are placed in a flowing hot water bath at 50℃ for 0.5-1 minutes to clean. Next, they are placed in an acid bath (total acidity 400-700 points, temperature ≥55℃) to pickle and remove oxide scale.

[0045] After removing the oxide scale, the blank is rinsed with running water at room temperature and then neutralized in a bath containing sodium bicarbonate (50–100 g / L, room temperature) for 0.5–1 min. The neutralized deep cylindrical blank is then treated in a bath containing phosphating solution (total acidity 100–140 points, room temperature) for 10–15 min to complete the phosphating treatment. It is then rinsed in a running cold water bath and then treated in a bath containing saponification solution (80–120 g / L industrial soap, temperature 30–65℃) for 10–15 min to complete the saponification treatment. The formation of a saponification film on the workpiece surface improves its lubrication properties.

[0046] This forms a phosphate film on the surface of the workpiece, thereby improving its lubrication performance. 2) The blank of the thin-walled deep cylindrical part is placed into the forming cavity 8 of the stretching die 2, and the guide die 201 keeps the thin-walled deep cylindrical part coaxial with the forming stamping part 702. At this time, the hydraulic press drives the forming stamping part 702 of the punch 7 to move downward, clamping and pressing the thin-walled deep cylindrical part between the forming stamping part 702 and the side wall of the forming cavity 8 of the stretching die 2. By causing the thin-walled deep cylindrical part to undergo plastic deformation, the stretching and forming of the thin-walled deep cylindrical part is achieved.

[0047] As the forming stamping part 702 continues to press downwards on the thin-walled deep cylindrical part, the scraper ring 10 resets under the action of the elastic element. When the forming stamping part 702 moves upwards, the bottom of the scraper ring 10 abuts against the thin-walled deep cylindrical part. As the forming stamping part 702 continues to move upwards, the scraper ring 10 can quickly disengage the thin-walled deep cylindrical part from the punch 7, completing the disassembly. At this time, the dimensions of the thin-walled deep cylindrical part after stretching and forming are: H≈350mm; φD≈62.55mm; T=1mm; C≤φ0.15mm.

[0048] 3) Place the thin-walled deep cylindrical parts processed by the device of this utility model in a heat treatment tempering furnace, keep them at 420°C for 1 hour, and then remove them from the furnace. Cool them to room temperature to eliminate stress, and you can get the finished thin-walled deep cylindrical parts with qualified mechanical properties.

[0049] Therefore, this utility model is essentially a device for shaping and stretching a workpiece into a thin-walled deep cylindrical part after heat treatment. Using this device, deformation (or in other words, deformation) of the thin-walled deep cylindrical part after heat treatment due to the removal of the pre-installed fixture can be completely prevented. Long-term experiments have proven that, compared with traditional methods for preventing quenching deformation of thin-walled deep cylindrical parts, the device used in this utility model significantly improves workpiece quality. Specifically, when using this device to prevent quenching deformation, the circular runout error of the thin-walled part is ≤0.15mm, which is significantly improved compared to workpieces produced by traditional methods (thin-walled circular runout error is 0.5-0.6mm).

[0050] Furthermore, traditional equipment can only assemble one workpiece per batch production, and to prevent deformation during quenching, it is difficult to adapt to batch production. In contrast, this equipment can continuously process multiple workpieces, which can effectively realize batch production. Moreover, the workpiece assembly and disassembly process is faster and simpler, which not only significantly improves production efficiency, but also effectively reduces the labor intensity of workers.

[0051] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications made to the present utility model by those skilled in the art without departing from the spirit of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A device for preventing quenching deformation of thin-walled deep cylindrical parts, characterized in that, Includes the upper mold mechanism and the lower mold mechanism; The lower mold mechanism includes a fixed base (1) and a stretching mold (2). A through hole is opened in the middle of the fixed base (1), and the stretching mold (2) is fixedly installed in the through hole. The upper mold mechanism includes a driving end and a supporting end. The driving end is connected to a power output mechanism to realize the up-and-down reciprocating motion of the upper mold mechanism. A shaping cavity (8) is provided in the middle of the stretching mold (2). The supporting end of the upper mold mechanism is used to extend into the shaping cavity (8) so that the workpiece (3) is located between the stretching mold (2) and the supporting end, so that the side wall of the workpiece (3) can be stretched after the workpiece (3) is heat-treated, thus completing the shaping of the workpiece (3). The lower mold mechanism also includes a scraping component disposed in the through hole of the fixed seat (1), which is used to smoothly separate the workpiece (3) from the upper mold mechanism after the workpiece (3) has been shaped.

2. The apparatus according to claim 1, characterized in that, The fixed base (1) has a first stepped surface (4) at one end of the through hole. The stretching mold (2) is engaged in the through hole so that the bottom surface of the stretching mold (2) abuts against the first stepped surface (4). A pressure plate (5) is also fixedly connected to the top of the fixed base (1). The pressure plate (5) abuts against the top of the stretching mold (2) to limit and fix the stretching mold (2).

3. The apparatus according to claim 2, characterized in that, The stretching die (2) includes a guide die (201), a lower die (202) for stretching the workpiece (3), and a shaping die (203), wherein the guide die (201), the lower die (202) and the shaping die (203) are stacked from top to bottom.

4. The apparatus according to claim 3, characterized in that, The width of the working zone of the lower die (202) is ≤5mm.

5. The apparatus according to claim 3, characterized in that, The width of the mold working zone of the shaping mold (203) ranges from 10 to 20 mm.

6. The apparatus according to claim 1, characterized in that, The upper mold mechanism includes a mounting base (6) and a punch (7). The punch (7) includes a positioning shoulder (701) and a forming stamping part (702). One end of the mounting base (6) is fixedly connected to the power output mechanism. The positioning shoulder (701) is snapped and fixed to the other end of the mounting base (6), so that the forming stamping part (702) and the forming cavity (8) of the stretching die (2) are coaxially arranged.

7. The apparatus according to claim 6, characterized in that, The forming stamping part (702) is provided with a first blind hole (7021) along the axial direction, and the forming stamping part (702) is provided with a second blind hole (7022) along the radial direction. The first blind hole (7021) and the second blind hole (7022) are connected.

8. The apparatus according to claim 1, characterized in that, The scraping assembly is located below the stretching die (2). The scraping assembly includes a base (9) and a scraping ring (10) formed by multiple scraping petals. The base (9) is snapped and fixed between the second step surface of the through hole and the bottom surface of the stretching die (2). The outer periphery of the base (9) is in close contact with the inner wall of the through hole. The outer periphery of the scraping ring (10) is elastically connected to the inner wall of the base (9) through multiple circumferentially distributed elastic elements.

9. The apparatus according to claim 3, characterized in that, The inner circumferential dimension of the lower die (202) is smaller than the inner circumferential dimension of the forming die (203).

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