A forming method for asymmetric single-hole frame die forgings

Abstract

The present invention relates to the technical field of metal non-cutting processing, specifically a method for forming an asymmetric single-hole frame die forging. The method comprises the following steps: S1: selecting the weight t1 of a bar according to the weight t of the asymmetric single-hole frame die forging; S2: heating the bar to a forging temperature, and after the core of the bar reaches the temperature, placing the bar on a fast forging machine to roughen it to a thickness H; S3: punching the bar after roughing in step 2, and after punching, expanding the hole using a horse bar to form an original blank after expansion; S4: fitting the original blank onto a forming tool to form a final blank; S5: placing the final blank on a die forging machine to form an asymmetric single-hole frame die forging. By using the forming method of the present invention, a ring-shaped final blank that follows the shape of the forging can be obtained. When designing the asymmetric single-hole frame die forging, no skin dressing is required, so that the material required for forming the asymmetric single-hole frame die forging is reduced by more than 30%, and the reduction in projected area also reduces the load required for forming by more than 20%.

Description

Technical Field

[0001] The invention relates to the technical field of metal non-cutting processing, in particular to a forming method of an asymmetric single-hole frame-type die forging. Background Art

[0002] In order to achieve design indicators such as lightweight, long life, and high reliability, the design of the main load-bearing structural parts of the new generation of aircraft is developing towards large-scale, integrated, and complex directions, and the manufacturing difficulty is increasing. Large frame and beam forgings are widely used in key parts of transport aircraft and various fighter fuselages and engines, such as Figure 1 The asymmetric single-hole frame-type die forging shown in the figure is also provided with a plurality of grooves on the upper surface of the asymmetric single-hole frame-type die forging, including a first semicircular portion and a second semicircular portion with openings opposite to each other, the diameter of the first semicircular portion is larger than the diameter of the second semicircular portion, the first end of the first semicircular portion is connected to the first end of the second semicircular portion by a first straight line segment, and the second end of the first semicircular portion is connected to the second end of the second semicircular portion by a first arc segment.

[0003] This type of special-shaped die forging is difficult to manufacture because of its asymmetric structure, which cannot be achieved by conventional ring rolling + die forging. The commonly used method is to pass the slab through the bar and die forge the entire part. However, with this method, the interior of the frame forging needs to be covered with a skin, which is then removed after the die forging process is completed, resulting in a large amount of material waste and extremely low material utilization. In addition, the streamlines of the forging are damaged, which will affect the fatigue life of the forging. At the same time, if the size of this type of forging is large, adding a skin will significantly increase the projected area of ​​the forging, the required forming load will increase linearly, and the required equipment tonnage will also be very large. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a forming method for asymmetric single-hole frame-type die forgings, so as to realize fast and low-cost manufacturing of forgings and reduce the requirement on equipment tonnage.

[0005] The technical solution adopted by the present invention to solve the technical problem is a method for forming an asymmetric single-hole frame die forging, comprising the following steps:

[0006] S1: Select the weight t1 of the bar according to the weight t of the asymmetric single-hole frame die forging, where t1 = α*t, α∈(1.1-1.2);

[0007] S2: Heat the bar to the forging temperature. After the core of the bar reaches the temperature, place the bar on the high-speed forging machine and roughen it to a thickness of H, where H = β*h, β∈(1.1-1.2), and h is the thickness of the asymmetric single-hole frame die forging;

[0008] S3: Punching the bar after the roughening in step 2, and then expanding the hole with a horse bar to form an original blank after the hole expansion. The circumference of the inner hole of the original blank is the same as the circumference of the inner hole of the asymmetric single-hole frame type die forging, and the width of the original blank is consistent with the width of the asymmetric single-hole frame type die forging;

[0009] S4, placing the original blank on a forming tool, the forming tool comprising a cylindrical table, a forming table and a plurality of punches, the forming table comprising a first arc surface matching the inner surface of the first semicircular portion, a second arc surface matching the inner surface of the second semicircular portion, a third arc surface matching the inner surface of the first arc segment, and a first plane matching the inner surface of the first straight segment, the first arc surface, the second arc surface, the third arc surface and the first plane all smoothly transitioning to the outer surface of the cylindrical table via a transition surface; the original blank is placed on the cylindrical table, the plurality of punches contacting the upper surface of the original blank, and the punches are driven downward by a press to push the original blank downward along the transition surface until the inner surface of the original blank is sequentially fitted with the first arc surface, the second arc surface, the third arc surface and the first plane to form a final blank;

[0010] S5: The final blank is placed on a die forging machine to form an asymmetric single-hole frame-type die forging.

[0011] Furthermore, the circumference of the outer surface of the cylindrical platform is consistent with the circumference of the outer surface of the forming platform.

[0012] Furthermore, in step S4, when the multiple punches push the original blank downward, the punches need to continuously adjust the contact points with the upper surface of the original blank.

[0013] Furthermore, the high-speed forging machine is a 45MN high-speed forging machine.

[0014] The beneficial effect of the present invention is that: through the forming method of the present invention, a ring-shaped final blank that follows the shape of an asymmetric single-hole frame type die forging can be obtained. There is no need to add skin dressing when designing the asymmetric single-hole frame type die forging, so that the material required for the forming of the asymmetric single-hole frame type die forging is reduced by more than 30%. The reduction in projected area also reduces the load required for forming by more than 20%, which makes it possible to manufacture large-sized forgings on small equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic structural diagram of an asymmetric single-hole frame die forging according to the present invention;

[0016] Figure 2 It is a schematic diagram of the formation from the initial rough block to the final rough block;

[0017] Figure 3 This is a bottom view of the molding tool.

[0018] Figure markings: 1-first semicircular portion; 2-second semicircular portion; 3-first straight portion; 4-first arc portion; 5-original blank; 6-cylindrical table; 7-forming table; 701-first arc surface; 702-second arc surface; 703-third arc surface; 704-first plane; 8-punch; 9-transition surface; 10-final blank. DETAILED DESCRIPTION

[0019] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0020] like Figure 2 and Figure 3 As shown, the present invention provides a method for forming an asymmetric single-hole frame die forging, comprising the following steps:

[0021] S1: Select the weight t1 of the bar according to the weight t of the asymmetric single-hole frame die forging, where t1 = α*t, α∈(1.1~1.2); since a small amount of flash will always appear during the die forging process, when selecting the bar weight t1, the bar weight must be greater than the weight t of the asymmetric single-hole frame die forging.

[0022] S2: Heat the bar to the forging temperature, and after the core of the bar reaches the temperature, place the bar on the fast forging machine and roughen it to a thickness of H, where H = β*h, β∈(1.1~1.2), and h is the thickness of the asymmetric single-hole frame type die forging; when performing die forging, the upper die is provided with a boss that matches the groove on the asymmetric single-hole frame type die forging, and the lower die is provided with a groove that matches the shape of the asymmetric single-hole frame type die forging. Therefore, when roughening the bar, the width of the subsequent original blank is consistent with the width of the asymmetric single-hole frame type die forging, so the thickness can only be made greater than the thickness of the asymmetric single-hole frame type die forging, so that the final formed blank can be placed in the groove of the lower die.

[0023] S3: Punch the bar after being roughened in step 2, and then use a horse bar to expand the hole after punching to form an original blank. The circumference of the inner hole of the original blank is the same as the circumference of the inner hole of the asymmetric single-hole frame type die forging, and the width of the original blank is consistent with the width of the asymmetric single-hole frame type die forging; the inner hole of the original blank is a standard circle, and when the original blank is subsequently formed into the final blank, only the outline shape of the blank will be changed. Therefore, it is necessary to ensure that the circumference of the inner hole of the original blank is the same as the circumference of the inner hole of the asymmetric single-hole frame type die forging, and the width of the original blank is consistent with the width of the asymmetric single-hole frame type die forging.

[0024] S4, see Figure 2 and Figure 3, the original blank is put on the forming tooling, the forming tooling includes a cylindrical table, a forming table and multiple punches, the forming table includes a first arc surface matching the inner surface of the first semicircular portion, a second arc surface matching the inner surface of the second semicircular portion, a third arc surface matching the inner surface of the first arc segment, and a first plane matching the inner surface of the first straight segment, the first arc surface, the second arc surface, the third arc surface and the first plane all smoothly transition to the outer surface of the cylindrical table through a transition surface; the original blank is put on the cylindrical table, multiple punches contact the upper surface of the original blank, and the punches are driven downward by the press to push the original blank downward along the transition surface until the inner surface of the original blank is aligned with the first arc surface in sequence The first arc surface, the second arc surface, the third arc surface and the first plane are fitted together to form a final blank; the circumference of the outer surface of the cylindrical table is consistent with the circumference of the outer surface of the forming table, and the cylindrical table plays a positioning role to ensure that the inner surface of the original blank is fitted with the outer side surface of the cylindrical table. In the process of using the punch to push the original blank downward, the inner surface of the original blank will gradually deform under the action of the transition surface until the inner surface of the original blank is fitted with the first arc surface, the second arc surface, the third arc surface and the first plane in sequence. In this way, the shape of the inner surface of the original blank can be changed. During the forming process, the thickness of the original blank remains unchanged, and the final blank formed is the same as the overall shape of the asymmetric single-hole frame-type die forging.

[0025] S5: The final blank is placed on a die forging machine for forming, and after removing the flash and burrs, an asymmetric single-hole frame-type die forging is formed.

[0026] Since the shape of the original blank will continue to change during the downward movement of the punch, there may be interference between the cylindrical table or transition surface and the punch. Furthermore, in step S4, when multiple punches push the original blank downward, the punch needs to continuously adjust the contact point with the upper surface of the original blank.

[0027] Furthermore, the high-speed forging machine is a 45MN high-speed forging machine.

[0028] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for forming an asymmetric single-hole frame die forging, characterized in that: The following steps are included: S1: Select the weight t1 of the bar according to the weight t of the asymmetric single-hole frame die forging, where t1 = α*t, α∈ (1.1～1.2)； S2: Heat the bar to the forging temperature. After the core of the bar reaches the temperature, place the bar on the high-speed forging machine and roughen it to a thickness of H, where H = β*h, β∈(1.1-1.2), and h is the thickness of the asymmetric single-hole frame die forging; S3: Punching the bar after the roughening in step 2, and then expanding the hole with a horse bar to form an original blank after the hole expansion. The circumference of the inner hole of the original blank is the same as the circumference of the inner hole of the asymmetric single-hole frame type die forging, and the width of the original blank is consistent with the width of the asymmetric single-hole frame type die forging; S4, placing the original blank on a forming tool, the forming tool comprising a cylindrical table, a forming table and a plurality of punches, the forming table comprising a first arc surface matching the inner surface of the first semicircular portion, a second arc surface matching the inner surface of the second semicircular portion, a third arc surface matching the inner surface of the first arc segment, and a first plane matching the inner surface of the first straight segment, the first arc surface, the second arc surface, the third arc surface and the first plane all smoothly transitioning to the outer surface of the cylindrical table via a transition surface; the original blank is placed on the cylindrical table, the plurality of punches contacting the upper surface of the original blank, and the punches are driven downward by a press to push the original blank downward along the transition surface until the inner surface of the original blank is sequentially fitted with the first arc surface, the second arc surface, the third arc surface and the first plane to form a final blank; S5: The final blank is placed on a die forging machine to form an asymmetric single-hole frame-type die forging.

2. The method for forming an asymmetric single-hole frame die forging according to claim 1, wherein: The circumference of the outer surface of the cylindrical platform is consistent with the circumference of the outer surface of the forming platform.

3. The method for forming an asymmetric single-hole frame die forging according to claim 1, wherein: In step S4, when the multiple punches push the original blank downward, the punches need to continuously adjust the contact points with the upper surface of the original blank.

4. The method for forming an asymmetric single-hole frame die forging according to claim 1, wherein: The high-speed forging machine is a 45MN high-speed forging machine.

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