Preparation method of thin-wall L-shaped flange ring piece

Abstract

The invention relates to the technical field of plastic forming, in particular to a preparation method of a thin-wall L-shaped flange ring piece. The preparation method of the thin-wall L-shaped flange ring piece comprises the following steps that (a) a bar subjected to heat preservation treatment is subjected to upsetting, drawing and cogging, and then punching and ring rolling are conducted to obtain a ring blank; (b) gradually flanging and forming one end of the ring blank subjected to heat preservation treatment to obtain a blank with a trumpet-shaped opening in one end; and performing end face rolling on the trumpet-shaped opening end of the blank until an included angle of 90 degrees is formed between the trumpet-shaped opening end and the axial direction. According to the preparation method of the thin-wall L-shaped flange ring piece, progressive flanging forming is matched with end face rolling, and the problem that the thin-wall L-shaped flange ring piece is difficult to integrally form is solved; and compared with an existing cutting forming mode, the material utilization rate is remarkably increased, the material streamline is reserved, and the mechanical property is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of plastic forming, and in particular to a method for preparing a thin-wall L-shaped flange ring. Background Art

[0002] Thin-walled L-shaped flange ring is one of the key parts of aircraft engines and automobile wheels. The main geometric features of this part 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] Since the part has a thin wall thickness and a large 90° flange, it is difficult to form as a whole. In the existing processing method of the part, a rectangular ring blank with the same radial size as the flange is first rolled out, and then an L-shaped ring that meets the wall thickness requirements is cut out. In the existing forming method, the material utilization rate is extremely low, and the cutting seriously damages the metal flow line, affecting the mechanical properties of the product.

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

[0005] The purpose of the present invention is to provide a method for preparing a thin-walled L-shaped flange ring, which solves the problem that the existing part is difficult to form as a whole, and can greatly improve production efficiency and material utilization, reduce production costs, and avoid damage to metal streamlines.

[0006] In order to achieve the above-mentioned object of the present invention, the present invention provides a method for preparing a thin-walled L-shaped flange ring, comprising the following steps:

[0007] (a) The heat-insulated bar material is upset and drawn into a blank, and then punched and ring-rolled to obtain a ring blank;

[0008] (b) performing progressive flanging on one end of the heat-insulated ring blank to obtain a blank having a trumpet-shaped opening at one end; and performing end surface rolling on the trumpet-shaped opening end of the blank until an angle of 90° is formed 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 4-10 mm.

[0010] In a specific embodiment of the present invention, in the blank with the trumpet-shaped opening, the angle between the trumpet-shaped side wall 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 performed by 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, and the core roll of the ring rolling mill includes a cylindrical roll core and an inverted frustum core roll sleeve coaxially sleeved on the roll core. Furthermore, the angle between the frustum generatrix of the core roll sleeve and the axial direction is 20° to 40°.

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

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

[0016] In a specific embodiment of the present invention, the lower end horizontal height of the core roller sleeve is higher than the upper end horizontal height of the inner mold; or, the lower end horizontal height of the core roller sleeve is flush with the upper end horizontal height 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 trumpet-shaped opening in a forming die, and applying axial pressure to the trumpet-shaped opening end of the blank using an upper tapered roller. Further, the forming die is provided with an annular groove corresponding to the non-deformed end of the blank, the height of the inner side 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 side wall and the outer side wall of the annular groove is the same as the thickness of the radially extending surface of the thin-walled L-shaped flange ring.

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

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

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The method for preparing a thin-walled L-shaped flange ring of the present invention solves the problem that a thin-walled L-shaped flange ring is difficult to integrally form by progressive flanging and end face rolling; and compared with the existing cutting forming method, the method significantly improves the material utilization rate, retains the material streamline, and ensures the 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 low equipment requirements; and progressive flanging and end face rolling can be completed in one fire on a ring rolling machine, which is simple to operate, improves work efficiency, and saves energy and manpower. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0026] Figure 2 A schematic diagram of a first pass progressive flanging provided by an embodiment of the present invention;

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

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

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

[0030] Figure 6 A schematic diagram of the structure and dimensions of a ring blank provided in Example 1 of the present invention;

[0031] Figure 7 A schematic diagram of the structural dimensions of the outer mold provided in Example 1 of the present invention;

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

[0033] Reference numerals:

[0034] 1-Ring blank; 2-Blank material; 3-Roller core;

[0035] 4-core roller sleeve; 5-inner mold; 6-outer mold;

[0036] 7-aluminum alloy ring; 8-forming die; 9-upper cone roller;

[0037] 81- Annular groove. DETAILED DESCRIPTION

[0038] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0039] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

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

[0042] Based on this, the present invention has developed a method for integrally forming a thin-walled L-shaped flange ring. Through progressive flanging and end face rolling, not only the material utilization rate is improved, but also the material flow line is retained to ensure the mechanical properties. In addition, both progressive flanging and end face rolling are local plastic forming, which reduces the requirements for equipment.

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

[0044] (a) The heat-insulated bar material is upset and drawn into a blank, and then punched and ring-rolled to obtain a ring blank;

[0045] (b) performing progressive flanging on one end of the heat-insulated ring blank to obtain a blank having a trumpet-shaped opening at one end; and performing end face rolling on the trumpet-shaped opening end of the blank until an angle of 90° is formed 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 4-10 mm.

[0047] For example, in different embodiments, the wall thickness of the thin-walled L-shaped flange ring may be 4 mm, 5 mm, 8 mm, 10 mm, or a range consisting of any two of these.

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

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

[0050] For example, in different embodiments, in the blank with a trumpet-shaped opening, the angle between the trumpet-shaped side wall and the axial direction can be 40°, 50°, 60°, 70°, 80°, or a range consisting of any two thereof. For example, after the progressive flanging, in the blank with a trumpet-shaped opening at one end, the angle between the side wall of the trumpet-shaped opening and the axial direction can be 40° to 60°, which is more conducive to taking into account the stability and forming efficiency of the progressive flanging and the end face rolling.

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

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

[0053] In a specific embodiment of the present invention, when single-pass progressive flanging is adopted, subsequent end face rolling can be performed directly without returning to the furnace for heat preservation; when multi-pass progressive flanging is adopted, subsequent end face rolling can be performed after conventional returning to the furnace for heat preservation.

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

[0055] In a specific embodiment of the present invention, the method of progressive flanging includes: fixing the non-deformed end of the ring blank 1 between a coaxially arranged inner mold 5 and an outer mold 6; during the core roller feeding process, 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 portion to be flanging of the ring blank 1, radial pressure is applied to the portion to be flanging, so that the portion to be flanging is flanging outward.

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

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

[0058] In a specific embodiment of the present invention, the lower end level of the core roller sleeve 4 is higher than the upper end level of the inner mold 5 ; or, the lower end level of the core roller sleeve 4 is flush with the upper end level 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. Further, 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 process of progressive flanging, the inner die 5 and the outer die 6 are installed on the rolling mill platform, the non-deformed end of the ring blank 1 is fixed between the inner die 5 and the outer die 6 which are coaxially arranged, and then the aluminum alloy ring 7 is arranged between the cylindrical roller core at the bottom of the core roller sleeve 4 of the core roller and the inner die 5. When the ring rolling mill is turned on, the core roller extrude the aluminum alloy ring 7 at a horizontal feed speed v and approaches the ring blank 1, and at the same time, the main roller drives the inner die 5, the outer die 6 and the ring blank 1 to rotate together at an angular velocity ω; when the conical surface of the core roller sleeve 4 contacts the ring blank 1, the part of the ring blank 1 to be flanging is partially rolled horizontally, and the progressive flanging forms an opening of a certain angle. In the process of the core roller extruding the aluminum alloy ring 7 at a horizontal feed speed v and approaching the ring blank 1, the wall thickness of the aluminum alloy ring 7 is rolled and thinned, which can ensure that the core roller continuously applies extrusion force to the inner die 5 and the outer die 6, and can ensure that the core roller approaches the ring blank 1 at a uniform speed, and ensure that a stable deformation force is applied to the ring blank 1.

[0061] In actual operation, the outer diameter of the aluminum alloy ring 7 is the same as the inner diameter of the inner die 5. The volume of the aluminum alloy ring 7 satisfies that: after the single-pass progressive flanging is completed, the height of the deformed aluminum alloy ring does not exceed the height of the inner die 5. The strength of the material of the aluminum alloy ring 7 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 is heated before use. For example, the heating temperature can be 420-450°C. The material of the aluminum alloy ring 7 in the following specific embodiment is described by taking 1 series aluminum alloy as an example, and is preheated to 450°C before use.

[0062] If multiple passes of progressive flanging forming process are required, the progressive flanging forming process of each pass is basically the same, and the passes of the progressive flanging forming are conventionally adjusted according to the opening angle after the progressive flanging forming.

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

[0064] Figure 4Schematic diagram of end face rolling provided for an embodiment of the present invention. In a specific embodiment of the present invention, end face rolling includes: placing a blank 2 having a trumpet-shaped opening in a forming die 8, and applying axial pressure to the trumpet-shaped opening end of the blank 2 using an upper tapered roller 9. Further, the forming die 8 is provided with an annular groove 81 corresponding to the non-deformed end of the blank 2, the height of the inner side wall 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 side wall and the outer side wall of the annular groove 81 is the same as the thickness of the radially extending surface of the thin-walled L-shaped flange ring.

[0065] In the end face rolling, the conical surface of the upper conical roller 9 rolls the upper end face of the blank 2, and the upper conical roller 9 feeds downward on the one hand and rotates around its conical axis on the other hand. If the end face rolling is processed on an end face rolling machine, during the end face rolling process, the upper conical roller 9 drives the blank 2 to rotate together with the forming die 8; if the end face rolling is added on a ring rolling machine, the main rolling 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 fits with the top of the inner side wall of the annular groove 81 of the forming die 8, the cavity enclosed 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 pressing speed of the upper tapered roller 9 can be 1-3 mm / s, for example, 1 mm / s, 1.5 mm / s, 2 mm / s, 2.5 mm / s, 3 mm / s or a range consisting of any two thereof, and the rotating speed can be 180-360 rad / min, for example, 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 a range consisting of any two thereof.

[0067] In a specific embodiment of the present invention, the upsetting and drawing process includes three upsetting and two drawing processes. Specifically, the three upsetting and two drawing processes can be performed according to conventional operations.

[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 component, 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 component.

[0069] In actual operation, the blanking weight and blanking specifications are determined according to the forging drawing of the target thin-walled L-shaped flange ring, and a rectangular cross-section ring blank 1 with a size that meets the above conditions is made using round bars.

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

[0071] (1) Cutting: According to the geometric shape of the target thin-walled L-shaped flange ring, the specifications and weight of the blank are calculated and determined, and the blank is cut from the round bar using a sawing machine;

[0072] (2) Heating: According to the thermoplastic forming requirements of the blank material, the blank is heated to the forgeable temperature of the material, and after being kept warm, it is taken out of the furnace for subsequent forging;

[0073] (3) Forging: The blank is upset along the axial direction, and then stretched along the axial direction, and this process is repeated three times and two times;

[0074] (4) Punching: After heating the blank, use a punch to punch, then round and trim the blank and return it to the furnace for heat preservation;

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

[0076] In a specific embodiment of the present invention, during the heat preservation treatment, the heat preservation temperature is T β -50℃~T β -20℃, where T β is the phase transition point temperature of the ring blank 1. The time of the heat preservation treatment satisfies: the shortest is H×0.5min / mm, the longest is H×1.2min / mm+240min, and H is the effective thickness of the blank, in mm.

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

[0078] In a specific embodiment of the present invention, the method further comprises: performing annealing heat treatment on the forged piece after end face rolling. Furthermore, in the annealing heat treatment, the forged piece is kept 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 structure size diagram is as follows: Figure 5 As shown, the forging size is appropriately increased on one side based on the final ring size. The ring is made of TC4, and the corresponding forging size is: maximum outer diameter is 1904mm, straight wall inner diameter is 1789mm, straight wall outer diameter is 1821mm, height is 60mm, and the thickness of the radial extension surface is 17mm.

[0081] The method for preparing the thin-walled L-shaped flange ring of this embodiment may use equipment including but not limited to a forging heating furnace, a die forging press, a ring rolling machine, a manipulator, etc. The specific method includes the following steps:

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

[0083] (2) Heat the bar to the phase transition point temperature T β The temperature is kept below 40-45℃ for 180min. Then the bar is subjected to three-stage and two-stage drawing, punching, and ring rolling on a ring rolling mill to obtain the following Figure 6 Ring blank shown.

[0084] (3) After the ring billet is returned to the furnace for 90 minutes, the ring billet is subjected to two-pass progressive flanging by a ring rolling mill. Figure 2 and Figure 3 Assembly method; specifically, the progressive flanging forming includes: installing an inner mold and an outer mold on the rolling mill platform, fixing the non-deformed end of the ring blank between the coaxially arranged inner mold and outer mold, and then setting an aluminum alloy ring between the cylindrical roller core at the bottom of the core roller sleeve of the core roller and the inner mold; turning on the ring rolling mill, the core roller extrude the aluminum alloy ring at a horizontal feed speed v and approaches the ring blank, while the main rolling roller drives the inner mold, the outer mold and the ring blank to rotate together at an angular velocity ω; when the conical surface of the core roller sleeve contacts the ring blank, the part of the blank to be flanging is partially rolled horizontally, and the progressive flanging forms an opening of a certain angle. Among them, the schematic diagrams of the structural dimensions of the outer mold and the inner mold used in this embodiment are respectively as shown in Figure 7 and Figure 8 As shown, the angle between the cone generatrix 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; this embodiment performs two passes of progressive flanging, the first pass of progressive flanging forms an opening with an angle of 30° to the axial direction, and the second pass of progressive flanging forms an opening with an angle of 60° to the axial direction.

[0085] (4) After the blank obtained in step (3) is returned to the furnace for heat preservation for 90 minutes, end face rolling is performed; the end face rolling comprises: placing the blank in a forming mold, using an upper conical roller to apply axial pressure to the trumpet-shaped open end of the blank until an angle of 90° is formed with the axial direction; wherein the pressing speed of the upper conical roller is 2 mm / s, and the rotation speed is 180 rad / min.

[0086] (5) The ring obtained in step (4) is kept at 780-790° C. for 80-90 min and then air-cooled.

[0087] Example 2

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

[0089] The method for preparing a thin-walled L-shaped flange ring of the present invention solves the problem that it is difficult to integrally form a thin-walled L-shaped flange ring by combining progressive flanging and end face rolling. Moreover, compared with the existing cutting forming method, the method of the present invention can save more than 60% of materials and significantly improve material utilization. The thin-walled L-shaped flange ring obtained by the method of the present invention retains the streamline of the material and has higher forming performance. Moreover, the progressive flanging and end face rolling of the present invention can be completed in one fire on a ring rolling machine, which is simple to operate, improves work efficiency, and saves energy and manpower. In addition, compared with flanging and then flattening on a hydraulic press, progressive flanging and end face rolling are local plastic forming methods, which require small forming force and have low equipment requirements.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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: The steps include: (a) The heat-insulated bar material is upset and drawn into a blank, and then punched and ring-rolled to obtain a ring blank; (b) performing progressive flanging on one end of the heat-insulated ring blank to obtain a blank having a trumpet-shaped opening at one end; and performing end surface rolling on the trumpet-shaped opening end of the blank until an angle of 90° is formed with the axial direction.

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

3. The method for preparing a thin-walled L-shaped flange ring according to claim 1, characterized in that: In the blank with the trumpet-shaped opening, the angle between the trumpet-shaped side wall and the axial direction is 40° to 80°, preferably 40° to 60°.

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

5. The method for preparing a thin-walled L-shaped flange ring according to claim 1, characterized in that: The progressive flanging is performed by a ring rolling machine, wherein the core roll of the ring rolling machine comprises a cylindrical roll core and an inverted frustum core roll sleeve coaxially sleeved on the roll core; Preferably, the angle between the frustum generatrix of the core roller sleeve and the axial direction is 20° to 40°.

6. The method for preparing a thin-walled L-shaped flange ring according to claim 5, characterized in that: The method for progressive flanging includes: fixing the non-deformed end of the ring blank between a coaxially arranged inner mold and an outer mold, and during the core roller feeding process, the conical surface of the core roller sleeve contacts the inner wall of the portion to be flanging of the ring blank and causes the portion to be flanging to be flanging outward.

7. The method for preparing a thin-walled L-shaped flange ring according to claim 6, characterized in that: In the progressive flanging forming, an aluminum alloy ring is arranged between the inner mold and the roller core of the core roller, and the aluminum alloy ring is arranged coaxially with the inner mold; Preferably, in the progressive flanging forming, the roller core located at the bottom of the core roller sleeve is abutted against the inner mold through the aluminum alloy ring.

8. The method for preparing a thin-walled L-shaped flange ring according to claim 6, characterized in that: The lower end of the core roller sleeve has a higher level than the upper end of the inner mold; or, the lower end of the core roller sleeve has a level with the upper end of the inner mold; Preferably, the height of the outer mold is higher than the height of the inner mold; Preferably, the height of the outer mold is the same as the axial height of the thin-walled L-shaped flange ring.

9. The method for preparing a thin-walled L-shaped flange ring according to claim 1, characterized in that: The end surface rolling comprises: placing a blank with a trumpet-shaped opening in a forming die, and applying axial pressure to the trumpet-shaped opening end of the blank using an upper tapered roller; Preferably, the forming mold is provided with 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 wall and the outer wall of the annular groove is the same as the thickness of the radial extension surface of the thin-walled L-shaped flange ring.

10. The method for preparing a thin-walled L-shaped flange ring according to claim 1, characterized in that: The material of the bar material includes TC4 alloy; Preferably, the preparation method further comprises: performing annealing heat treatment on the forging after end face rolling; Preferably, in the annealing heat treatment, the material is kept at 700-800° C. for 60-240 min and then air-cooled.

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