Method for manufacturing thin-walled l-shaped flange ring piece

Abstract

This invention relates to the field of plastic forming technology, and in particular to a method for preparing a thin-walled L-shaped flange ring. The method for preparing the thin-walled L-shaped flange ring includes the following steps: (a) upsetting and drawing a heat-insulated bar stock, followed by punching and ring rolling to obtain a ring blank; (b) progressively flanging one end of the heat-insulated ring blank to obtain a blank with a flared opening at one end; and end-face rolling of the flared opening end of the blank until it forms a 90° angle with the axial direction. The method for preparing the thin-walled L-shaped flange ring of this invention solves the problem of the difficulty in integrally forming thin-walled L-shaped flange rings through progressive flanging combined with end-face rolling; and compared with existing cutting forming methods, it significantly improves material utilization while preserving material flow lines and ensuring mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of plastic forming technology, and in particular to a method for preparing a thin-walled L-shaped flange ring. Background Technology

[0002] Thin-walled L-shaped flange rings are one of the key components of aircraft engines and automobile wheel hubs. The main geometric characteristics of this component include: (1) wall thickness between 4 and 10 mm; (2) straight wall inner diameter greater than 600 mm; (3) 90° flange with large radial area.

[0003] Because this part has both a relatively thin wall thickness and a large proportion of 90° flanges, it is difficult to form it as a single piece. The existing processing method for this part involves first rolling a rectangular ring blank with the same radial dimension as the flange, and then cutting an L-shaped ring that meets the wall thickness requirements. This existing forming method has extremely low material utilization and severely damages the metal flow lines during cutting, affecting the mechanical properties of the product.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a method for manufacturing a thin-walled L-shaped flange ring, which solves the problem of the difficulty in integral forming of the existing part, and can greatly improve production efficiency and material utilization, reduce production costs, and avoid damage to the metal flow lines.

[0006] To achieve the above-mentioned objectives of this invention, this invention provides a method for preparing a thin-walled L-shaped flange ring, comprising the following steps:

[0007] (a) The heat-insulated bar stock is upturned and drawn into a blank, and then punched and rolled into a ring blank;

[0008] (b) The end of the heat-insulated ring blank is progressively flanged to obtain a blank with a flared opening at one end; the flared opening end of the blank is rolled until it forms a 90° angle with the axial direction.

[0009] In a specific embodiment of the present invention, the wall thickness of the thin-walled L-shaped flange ring is 4 to 10 mm.

[0010] In a specific embodiment of the present invention, in the blank with the flared opening, the angle between the flared sidewall and the axial direction is 40° to 80°, preferably 40° to 60°.

[0011] In a specific embodiment of the present invention, the progressive flanging forming is carried out using single-pass or multi-pass progressive flanging forming.

[0012] In a specific embodiment of the present invention, a ring rolling mill is used for the progressive flanging forming. The mandrel of the ring rolling mill includes a cylindrical mandrel and an inverted frustum-shaped mandrel sleeve coaxially sleeved on the mandrel. Further, the angle between the generatrix of the frustum-shaped mandrel sleeve and the axial direction is 20° to 40°.

[0013] In a specific embodiment of the present invention, the progressive flanging forming method includes: fixing the non-deformable end of the ring blank between an inner mold and an outer mold arranged coaxially; during the core roller feeding process, the conical surface of the core roller sleeve contacts the inner wall of the portion of the ring blank to be flanged and causes the portion to be flanged to be flanged outward.

[0014] In a specific embodiment of the present invention, in the progressive flanging forming, an aluminum alloy ring is provided between the inner mold and the core of the core roller, and the aluminum alloy ring is coaxially arranged with the inner mold.

[0015] In a specific embodiment of the present invention, in the progressive flanging forming, the roller core located at the bottom of the core roller sleeve abuts against the inner mold through the aluminum alloy ring.

[0016] In a specific embodiment of the present invention, the lower end of the core roller sleeve is at a higher horizontal height than the upper end of the inner mold; or, the lower end of the core roller sleeve is at the same horizontal height as the upper end of the inner mold.

[0017] In a specific embodiment of the present invention, the height of the outer mold is higher than the height of the inner mold. Further, the height of the outer mold is the same as the axial height of the thin-walled L-shaped flange ring.

[0018] In a specific embodiment of the present invention, the end face rolling includes: placing a blank with a flared opening in a forming mold, and applying axial pressure to the flared opening end of the blank using an upper conical roller. Further, the forming mold has an annular groove corresponding to the non-deformed end of the blank, the height of the inner wall of the annular groove is the same as the axial height of the thin-walled L-shaped flange ring, and the height difference between the inner and outer walls of the annular groove is the same as the thickness of the radial extension surface of the thin-walled L-shaped flange ring.

[0019] In a specific embodiment of the present invention, the material of the bar stock includes TC4 alloy.

[0020] In a specific embodiment of the present invention, the method further includes: annealing the forging after end face rolling. Further, in the annealing heat treatment, the forging is held at 700–800°C for 60–240 minutes and then air-cooled.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] (1) The method for preparing the thin-walled L-shaped flange ring of the present invention solves the problem of the difficulty in integral forming of the thin-walled L-shaped flange ring by progressive flanging forming and end face rolling; and compared with the existing cutting forming method, it significantly improves the material utilization rate, retains the material flow line, and ensures mechanical properties.

[0023] (2) In the preparation method of the present invention, progressive flanging and end face rolling are local plastic forming methods, which require small forming force and have low equipment requirements; and progressive flanging and end face rolling can be completed in one operation on a ring rolling mill, which is simple to operate, improves work efficiency, and saves energy and manpower. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the core roller sleeve provided in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the first progressive flanging step provided in an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of the second progressive flanging provided in an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of end face rolling provided in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structural dimensions of the thin-walled L-shaped flange ring provided in Embodiment 1 of the present invention;

[0030] Figure 6 This is a schematic diagram of the structural dimensions of the ring blank provided in Embodiment 1 of the present invention;

[0031] Figure 7 This is a schematic diagram of the structural dimensions of the outer mold provided in Embodiment 1 of the present invention;

[0032] Figure 8 This is a schematic diagram of the structural dimensions of the inner mold provided in Embodiment 1 of the present invention.

[0033] Figure label:

[0034] 1-Ring billet; 2-Bill; 3-Roll core;

[0035] 4-Core roller sleeve; 5-Inner mold; 6-Outer mold;

[0036] 7-Aluminum alloy ring; 8-Forming die; 9-Upper conical roller;

[0037] 81- Annular groove. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. 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. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0039] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0041] In the existing processing of thin-walled L-shaped flange rings, a rectangular ring blank with the same radial dimension as the flange is first rolled, and then an L-shaped ring that meets the wall thickness requirements is cut. This processing method results in extremely low material utilization and severely damages the metal flow lines, affecting the mechanical properties of the product.

[0042] Based on this, the present invention develops a method for integrally forming thin-walled L-shaped flange rings. By using progressive flanging forming combined with end face rolling, not only is material utilization improved, but material flow lines are also preserved, ensuring mechanical properties. Furthermore, both progressive flanging and end face rolling are local plastic forming processes, reducing the requirements for equipment.

[0043] This invention provides a method for preparing a thin-walled L-shaped flange ring, comprising the following steps:

[0044] (a) The heat-insulated bar stock is upturned and drawn into a blank, and then punched and rolled into a ring blank;

[0045] (b) The end of the heat-insulated ring blank is progressively flanged to obtain a blank with a flared opening at one end; the flared opening end of the blank is rolled until it forms a 90° angle with the axial direction.

[0046] In a specific embodiment of the present invention, the wall thickness of the thin-walled L-shaped flange ring is 4 to 10 mm.

[0047] In different implementations, the wall thickness of the thin-walled L-shaped flange ring can be 4 mm, 5 mm, 8 mm, 10 mm, or any combination thereof.

[0048] In a specific embodiment of the present invention, the inner diameter of the straight wall and the maximum outer diameter of the thin-walled L-shaped flange ring can be adjusted according to the maximum and minimum production dimensions of the rolling mill used. The inner diameter of the straight wall of the thin-walled L-shaped flange ring can be >600mm, for example, it can be 650mm, 800mm, 1000mm, 1200mm, 1500mm, 1800mm, 2000mm or any combination thereof.

[0049] In a specific embodiment of the present invention, in a blank with a flared opening, the angle α between the flared sidewall and the axial direction is 40° to 80°.

[0050] In different embodiments, the angle between the flared sidewall and the axial direction in the blank with the flared opening can be 40°, 50°, 60°, 70°, 80°, or any combination thereof. For example, after progressive flanging, in the blank with a flared opening at one end, the angle between the sidewall of the flared opening and the axial direction can be 40° to 60°, which is more conducive to balancing the stability and forming efficiency of progressive flanging and end face rolling.

[0051] In a specific embodiment of the present invention, progressive flanging is performed using single-pass or multi-pass progressive flanging.

[0052] In different implementations, progressive flanging can be performed in one, two, three, or four passes, adjusted according to the forming properties of the material to prevent cracking caused by excessive stretching of the material during a single forming process. Typically, in single-pass progressive flanging, the flanging angle does not exceed 40°. The flanging angle refers to the difference between the angle between the sidewall of the blank on the flanging side and the axial direction before and after flanging. For example, in single-pass progressive flanging, the flanging angle can be 20°, 25°, 30°, 40°, or any combination thereof, preferably 30°, which is more conducive to improving processing efficiency while ensuring stability during deformation.

[0053] In a specific embodiment of the present invention, when a single-pass progressive flanging forming is used, subsequent end face rolling can be performed directly without the need for reheating in the furnace; when a multi-pass progressive flanging forming is used, subsequent end face rolling can be performed after conventional reheating in the furnace.

[0054] Figure 1 This is a schematic diagram of the core roller sleeve provided in an embodiment of the present invention. Figure 2 A schematic diagram of the first progressive flanging step provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the second-pass progressive flanging provided in an embodiment of the present invention. In a specific embodiment of the present invention, a ring mill is used for progressive flanging. The mandrel of the ring mill includes a cylindrical mandrel 3 and an inverted frustum mandrel sleeve 4 coaxially sleeved on the mandrel 3. The angle between the generatrix of the frustum mandrel sleeve 4 and the axial direction is 20° to 40°, such as 20°, 25°, 30°, 35°, 40°, or any combination thereof.

[0055] In a specific embodiment of the present invention, the progressive flanging forming method includes: fixing the non-deformable end of the ring blank 1 between the inner mold 5 and the outer mold 6 arranged coaxially; during the feeding process of the core roller, the core roller continuously approaches the ring blank 1; after the conical surface of the core roller sleeve 4 contacts the inner wall of the part to be flanged of the ring blank 1, radial pressure is applied to the part to be flanged, so that the part to be flanged is flanged outward.

[0056] In a specific embodiment of the present invention, in the progressive flanging forming, an aluminum alloy ring 7 is provided between the inner mold 5 and the core roller 3, and the aluminum alloy ring 7 is coaxially arranged with the inner mold 5.

[0057] In a specific embodiment of the present invention, in the progressive flanging forming, the roller core 3 located at the bottom of the core roller sleeve 4 abuts against the inner mold 5 through the aluminum alloy ring 7.

[0058] In a specific embodiment of the present invention, the lower end of the core roller sleeve 4 is at a higher horizontal height than the upper end of the inner mold 5; or, the lower end of the core roller sleeve 4 is at the same horizontal height as the upper end of the inner mold 5.

[0059] In a specific embodiment of the present invention, the height of the outer mold 6 is higher than the height of the inner mold 5. Furthermore, the height of the outer mold 6 is the same as the axial height of the thin-walled L-shaped flange ring.

[0060] In the progressive flanging process, an inner die 5 and an outer die 6 are installed on the rolling mill platform. The non-deformable end of the ring billet 1 is fixed between the coaxially arranged inner die 5 and outer die 6. Then, an aluminum alloy ring 7 is placed between the cylindrical roller core at the bottom of the mandrel sleeve 4 and the inner die 5. When the ring mill is started, the mandrel extrudes the aluminum alloy ring 7 at a horizontal feed speed v and moves it closer to the ring billet 1. At the same time, the main roll drives the inner die 5, outer die 6, and ring billet 1 to rotate together at an angular velocity ω. When the conical surface of the mandrel sleeve 4 contacts the ring billet 1, the part of the ring billet 1 to be flanged is locally rolled horizontally, and progressive flanging forms an opening at a certain angle. During the process of the mandrel extruding the aluminum alloy ring 7 at a horizontal feed speed v and moving it closer to the ring billet 1, the wall thickness of the aluminum alloy ring 7 is rolled and thinned. This ensures that the mandrel continuously applies extrusion pressure to the inner die 5 and outer die 6, and also ensures that the mandrel moves closer to the ring billet 1 at a uniform speed, ensuring that a stable deformation force is applied to the ring billet 1.

[0061] In actual operation, the outer diameter of the aluminum alloy ring 7 is the same as the inner diameter of the inner mold 5. The volume of the aluminum alloy ring 7 satisfies the following condition: after a single pass of progressive flanging, the height of the deformed aluminum alloy ring does not exceed the height of the inner mold 5. The strength of the aluminum alloy ring 7 material is less than the strength of the ring blank. For example, the aluminum alloy ring 7 can be made of 1-series aluminum alloy, and it is heat-treated before use, for example, at a temperature of 420–450°C. In the following specific embodiments, the material of the aluminum alloy ring 7 is described using 1-series aluminum alloy as an example, and it is preheated to 450°C before use.

[0062] If a multi-pass progressive flanging process is required, the progressive flanging process for each pass is basically the same. The number of passes for progressive flanging is adjusted according to the angle of the opening after progressive flanging.

[0063] In actual operation, the horizontal feed speed v of the core roll and the angular velocity ω of the main roll can be adjusted according to the actual processing stability. For example, v can be 0.1 to 5 mm / s and ω can be 40 to 80 rad / min.

[0064] Figure 4This is a schematic diagram of end-face rolling provided in an embodiment of the present invention. In a specific embodiment of the present invention, end-face rolling includes: placing a blank 2 with a flared opening in a forming mold 8, and applying axial pressure to the flared opening end of the blank 2 using an upper conical roller 9. Further, the forming mold 8 has an annular groove 81 corresponding to the non-deformed end of the blank 2. The height of the inner sidewall of the annular groove 81 is the same as the axial height of the thin-walled L-shaped flange ring, and the height difference between the inner and outer sidewalls of the annular groove 81 is the same as the thickness of the radial extension surface of the thin-walled L-shaped flange ring.

[0065] In the end-face rolling process, the cone face of the upper conical roller 9 rolls the upper end face of the blank 2. The upper conical roller 9 feeds downwards while rotating around its conical axis. If the end-face rolling is performed on an end-face rolling mill, the upper conical roller 9 drives the blank 2 and the forming die 8 to rotate together during the end-face rolling process. If the end-face rolling is performed on a ring rolling mill, the main roller drives the forming die 8 to rotate. The blank 2 undergoes continuous plastic deformation between the upper conical roller 9 and the forming die 8. The structural dimensions of the forming die 8 of the present invention are determined by the dimensions of the target thin-walled L-shaped flange ring, so that when the upper conical roller 9 is in contact with the top of the inner sidewall of the annular groove 81 of the forming die 8, the cavity formed by the upper conical roller 9 and the forming die 8 corresponds to the dimensions of the thin-walled L-shaped flange ring.

[0066] In actual operation, the downward pressing speed of the upper conical roller 9 can be 1 to 3 mm / s, for example, it can be 1 mm / s, 1.5 mm / s, 2 mm / s, 2.5 mm / s, 3 mm / s or any combination thereof, and the rotational speed can be 180 to 360 rad / min, for example, it can be 180 rad / min, 200 rad / min, 220 rad / min, 250 rad / min, 280 rad / min, 300 rad / min, 320 rad / min, 340 rad / min, 360 rad / min or any combination thereof.

[0067] In a specific embodiment of the present invention, upsetting and drawing of the billet includes three upsetting and two drawing operations. The specific three upsetting and two drawing operations can be carried out in accordance with conventional procedures.

[0068] In a specific embodiment of the present invention, the inner diameter of the ring blank 1 is the same as the inner diameter of the target thin-walled L-shaped flange ring, and the wall thickness of the ring blank 1 is the same as the wall thickness of the target thin-walled L-shaped flange ring.

[0069] In practice, based on the forging drawing of the target thin-walled L-shaped flange ring, the blanking weight and blanking specifications are determined, and a rectangular cross-section ring blank 1 with dimensions meeting the above conditions is made from round bar stock.

[0070] In a specific embodiment of the present invention, the preparation of the ring blank 1 may include the following steps:

[0071] (1) Blanking: Based on the geometry of the target thin-walled L-shaped flange ring, calculate and determine the specifications and weight of the blank, and use a saw to cut the blank on the round bar.

[0072] (2) Heating: According to the thermoplastic forming requirements of the billet material, the billet is heated to the forgeable temperature of the material, held at the temperature, and then taken out of the furnace for subsequent forging;

[0073] (3) Forging: Upsetting the billet along the axial direction, then drawing it along the axial direction, repeating this process three times upsetting and two times drawing;

[0074] (4) Punching: After heating the billet, punch holes with a punch, then roll the billet into a round shape and return it to the furnace for heat preservation.

[0075] (5) Ring rolling: The perforated billet after heat preservation is rolled into a rectangular cross-section ring billet of the corresponding size on a ring rolling mill and then returned to the furnace for heat preservation.

[0076] In a specific embodiment of the present invention, the heat preservation temperature is T during the heat preservation process. β -50℃~T β -20℃, where T β Let H be the phase transformation point temperature of the ring billet 1. The holding time must meet the following requirements: minimum H×0.5min / mm, maximum H×1.2min / mm+240min, where H is the effective thickness of the billet in mm.

[0077] In a specific embodiment of the present invention, the material of the bar stock includes TC4 alloy. The TC4 alloy comprises the following components by mass percentage: Al 5.5%–6.8%, V 3.5%–4.5%, Fe ≤0.3%, C ≤0.1%, N ≤0.05%, H ≤0.015%, O ≤0.2%, other elements individually ≤0.1% and their total ≤0.4%, with the balance being Ti.

[0078] In a specific embodiment of the present invention, the method further includes: annealing the forging after end face rolling. Further, in the annealing heat treatment, the forging is held at 700–800°C for 60–240 minutes and then air-cooled.

[0079] Example 1

[0080] This embodiment provides a thin-walled L-shaped flange ring, and the corresponding forging structural dimensions are shown in the schematic diagram below. Figure 5 As shown, the forging dimensions are based on the final ring dimensions with appropriate unilateral allowances. The ring is made of TC4 material, and the corresponding forging dimensions are: maximum outer diameter of 1904mm, straight wall inner diameter of 1789mm, straight wall outer diameter of 1821mm, height of 60mm, and thickness of the radial extension surface of 17mm.

[0081] The method for preparing the thin-walled L-shaped flange ring in this embodiment may use equipment including, but not limited to, a forging furnace, a die forging press, a ring rolling mill, and a robotic arm. The specific method includes the following steps:

[0082] (1) According to Figure 5 The structure of the thin-walled L-shaped flange ring shown is determined to use TC4 alloy bar material with a diameter of 60-70 mm and a weight 15% greater than that of the forged part after forming.

[0083] (2) Heat the bar stock to the phase transformation temperature T β The bar stock was then held at 40–45°C for 180 minutes; subsequently, it underwent three-stage upsetting and two-stage drawing, punching, and ring rolling on a ring mill to obtain the desired result. Figure 6 The ring blank shown.

[0084] (3) After the ring billet is returned to the furnace and held at that temperature for 90 minutes, it is subjected to two-pass progressive flanging forming using a ring rolling mill, as per reference. Figure 2 and Figure 3 The assembly method is as follows: Specifically, the progressive flanging forming includes: installing an inner mold and an outer mold on the rolling mill platform; fixing the non-deformable end of the ring billet between the coaxially arranged inner mold and outer mold; then placing an aluminum alloy ring between the columnar roller core at the bottom of the mandrel sleeve and the inner mold; starting the ring rolling mill, the mandrel extrudes the aluminum alloy ring at a horizontal feed speed v and moves it closer to the ring billet; simultaneously, the main roll drives the inner mold, outer mold, and ring billet to rotate together at an angular velocity ω; when the conical surface of the mandrel sleeve contacts the ring billet, the part of the billet to be flanged is locally horizontally rolled, and progressive flanging forms an opening at a certain angle. The structural dimensions of the outer mold and inner mold used in this embodiment are shown in the schematic diagrams below. Figure 7 and Figure 8 As shown, the angle between the generatrix of the frustum of the core roller sleeve 4 and the axial direction is 30°, the horizontal feed speed v is 2 mm / s, and the angular velocity ω is 60 rad / min. In this embodiment, two progressive flanging passes are performed. The first progressive flanging pass forms an opening at a 30° angle to the axial direction, and the second progressive flanging pass forms an opening at a 60° angle to the axial direction.

[0085] (4) After the billet obtained in step (3) is kept warm in the furnace for 90 minutes, end face rolling is performed. End face rolling includes: placing the billet in the forming mold and applying axial pressure to the horn-shaped opening end of the billet with the upper conical roller until it forms a 90° angle with the axial direction. The pressing speed of the upper conical roller is 2 mm / s and the rotation speed is 180 rad / min.

[0086] (5) Keep the ring obtained in step (4) at 780-790℃ for 80-90 minutes, and then air cool.

[0087] Example 2

[0088] This embodiment refers to the preparation method of embodiment 1, the only difference being that: the angle between the generatrix of the cone of the core roller sleeve 4 and the axial direction is 40°, the first pass progressive flanging forms an opening at a 40° angle with the axial direction, and the second pass progressive flanging forms an opening at an 80° angle with the axial direction.

[0089] The method for preparing thin-walled L-shaped flange rings of the present invention solves the problem of the difficulty in integral forming of thin-walled L-shaped flange rings through progressive flanging and end-face rolling. Furthermore, compared with existing cutting forming methods, the method of the present invention can save more than 60% of material, significantly improving material utilization. The thin-walled L-shaped flange rings obtained by the method of the present invention retain the material's streamline and have higher forming performance. Moreover, the progressive flanging and end-face rolling of the present invention can be completed in one pass on a ring rolling mill, simplifying operation, improving work efficiency, and saving energy and manpower. In addition, compared with flanging and flattening on a hydraulic press, progressive flanging and end-face rolling are localized plastic forming methods, requiring less forming force and having lower equipment requirements.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a thin-walled L-shaped flange ring, characterized in that, Includes the following steps: (a) The heat-insulated bar stock is upset and drawn into a blank, and then punched and rolled into a ring blank; (b) The end of the heat-insulated ring blank is progressively flanged to obtain a blank with a flared opening at one end; the flared opening end of the blank is rolled until it forms a 90° angle with the axial direction. The progressive flanging forming is performed using a ring rolling mill, wherein the core roll of the ring rolling mill includes a columnar core roll and an inverted frustum core roll sleeve coaxially sleeved on the core roll; The progressive flanging forming method includes: fixing the non-deformable end of the ring blank between an inner mold and an outer mold arranged coaxially; during the core roller feeding process, the conical surface of the core roller sleeve contacts the inner wall of the part of the ring blank to be flanged and causes the part to be flanged to be flanged outward. In the progressive flanging forming process, an aluminum alloy ring is provided between the inner mold and the core of the core roller, and the aluminum alloy ring is coaxially arranged with the inner mold. In the progressive flanging forming process, the roller core located at the bottom of the core roller sleeve abuts against the inner mold through the aluminum alloy ring.

2. The method for preparing the thin-walled L-shaped flange ring according to claim 1, characterized in that, The wall thickness of the thin-walled L-shaped flange ring is 4–10 mm.

3. The method for preparing the thin-walled L-shaped flange ring according to claim 1, characterized in that, In the blank with the flared opening, the angle between the flared sidewall and the axial direction is 40° to 80°.

4. The method for preparing the thin-walled L-shaped flange ring according to claim 3, characterized in that, The angle between the trumpet-shaped sidewall and the axial direction is 40° to 60°.

5. The method for preparing the thin-walled L-shaped flange ring according to claim 1, characterized in that, In the progressive flanging forming process, a single-pass or multi-pass progressive flanging forming method is adopted.

6. The method for preparing the thin-walled L-shaped flange ring according to claim 1, characterized in that, The angle between the generatrix of the frustum of the core roller sleeve and the axial direction is 20° to 40°.

7. The method for preparing the thin-walled L-shaped flange ring according to claim 1, characterized in that, The lower end of the core roller sleeve is at a higher horizontal height than the upper end of the inner mold; or, the lower end of the core roller sleeve is at the same horizontal height as the upper end of the inner mold.

8. The method for preparing the thin-walled L-shaped flange ring according to claim 7, characterized in that, The height of the outer mold is higher than the height of the inner mold.

9. The method for preparing the thin-walled L-shaped flange ring according to claim 7, characterized in that, The height of the outer mold is the same as the axial height of the thin-walled L-shaped flange ring.

10. The method for preparing the thin-walled L-shaped flange ring according to claim 1, characterized in that, The end face rolling includes: placing a blank with a flared opening in a forming mold, and applying axial pressure to the flared opening end of the blank using an upper conical roller.

11. The method for preparing the thin-walled L-shaped flange ring according to claim 10, characterized in that, The forming mold has an annular groove corresponding to the non-deformable end of the blank. The height of the inner wall of the annular groove is the same as the axial height of the thin-walled L-shaped flange ring. The height difference between the inner and outer walls of the annular groove is the same as the thickness of the radial extension surface of the thin-walled L-shaped flange ring.

12. The method for preparing the thin-walled L-shaped flange ring according to claim 1, characterized in that, The material of the bar stock includes TC4 alloy.

13. The method for preparing the thin-walled L-shaped flange ring according to claim 12, characterized in that, The preparation method further includes: annealing heat treatment of the forging after end face rolling; In the annealing heat treatment, the temperature is held at 700-800℃ for 60-240 minutes and then air-cooled.

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