A method for precision forging a passenger aircraft aluminum alloy piston seat

Abstract

The present application mainly relates to a passenger plane aluminum alloy piston seat precision forging forming method, comprising the following steps: S1: first fire time rough pressing preforming processing is carried out on the initial blank to obtain a single surface rough pressing part; S2: second fire time rough pressing preforming processing is carried out on the single surface rough pressing part to obtain a double surface rough pressing part; S3: pre-pressing forming processing is carried out on the double surface rough pressing part to obtain a pre-pressing part with a shape closer to the forged part; and S4: final-pressing forming processing is carried out on the pre-pressing part to obtain a die forging part with an overall structure precision forming. The processing steps of the passenger plane aluminum alloy piston seat precision forging forming method are optimized for the forming of the high rib structure area which is non-machined at the same time of obtaining the qualified formed die forging part, the forging forming process is redesigned based on the metal flow characteristics of the position of the high rib structure, and the generation of folding defects is avoided by changing the filling sequence of the metal at the position of the high rib structure.

Description

Technical Field

[0001] This invention belongs to the field of aluminum alloy material processing technology, and particularly relates to a method for precision forging of aluminum alloy piston seats for passenger aircraft. Background Technology

[0002] The piston housing is a crucial component of the passenger aircraft braking system, playing a vital role in the takeoff and landing phases and impacting flight safety. This type of component is structurally complex, has limited machining allowances, and requires high surface quality and mechanical properties, making it extremely difficult to form.

[0003] The piston seat component of passenger aircraft combines many difficult-to-form features such as high ribs, thin walls, deep cavities, small fillets, and small draft angles. Except for the assembly surface, all surfaces are non-machined, making it prone to problems like incomplete filling, folding, and flow defects during die forging. Folding defects in die forgings are formed when the oxidized surface metal clumps together during metal deformation; a common cause is the confluence of two or more metal flows. The occurrence of folding defects is closely related to the raw materials, the shape of the billet, the design of the die, the arrangement of the forming process, lubrication, and the actual forging operation. Folding defects not only reduce the load-bearing area of ​​the part, but also often become a source of fatigue due to stress concentration at these points during operation. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a precision forging method for aluminum alloy piston seats for passenger aircraft, which can effectively solve technical problems such as incomplete filling and folding defects in high-rib structures that are prone to occur during the precision forging process of aluminum alloy piston seats for passenger aircraft.

[0005] A method for precision forging an aluminum alloy piston seat for passenger aircraft includes the following steps:

[0006] Step S1: Perform a first-stage pre-forming process on the initial blank to obtain a single-sided pre-formed part; the upper die used in the first-stage pre-forming process is a flat upper die, and the lower die used is a pre-forming lower die. The pre-forming lower die is provided with a rib cavity structure for forming high-rib structures; the upper surface of the single-sided pre-formed part is a planar structure, and a circular inner groove is formed in the middle of the lower surface. The circular inner groove contains a high-rib structure formed in the radial direction. There are 7 high-rib structures, which are arranged at equal intervals in the circular inner groove.

[0007] Step S2: Perform a second pressing pre-forming process on the single-sided pressed part to obtain a double-sided pressed part; the upper die used in the second pressing process is a pressing upper die, and the lower die used is the same as the pressing lower die used in step S1. The pressing upper die is provided with a forming cavity for forming the upper surface structure of the single-sided pressed part; the shape of the high rib structure on the lower surface of the single-sided pressed part does not change during the second pressing process.

[0008] Step S3: Perform pre-pressing forming on the double-sided blank to obtain a pre-pressed part with a shape closer to that of a forging; during the pre-pressing forming process, further form the upper surface structure of the double-sided blank, and at the same time, perform local shaping on the high rib structure on the lower surface of the double-sided blank.

[0009] Step S4: Perform final pressing forming on the pre-pressed part to obtain a die forging with a precision integral structure.

[0010] Preferably, the initial blank used in step S1 is a disc-shaped blank. After the first pressing is completed, the position, width, and draft angle of the high rib structure on the lower surface of the single-sided pressed part are the same as the high rib structure on the lower surface of the die forging obtained after step S4. The height of the high rib structure on the side near the center of the single-sided pressed part is lower than the height on the side near the edge of the single-sided pressed part, and a raised arc-shaped structure is formed in the middle of the top of each group of high rib structures. The height of the raised part of the arc-shaped structure is 5mm.

[0011] Preferably, after step S2 is completed, a frustum-shaped central protrusion structure is formed on the upper surface of the double-sided pressed part, and seven frustum-shaped outer protrusion structures are uniformly formed around the central protrusion structure. The diameter of the central protrusion structure is φ124mm and the height is 15mm, and the outer contour diameter of the outer protrusion structure is φ70mm and the height is 12.5mm.

[0012] Preferably, after step S3 is completed, the arc-shaped top of the high-rib structure is pressed down to fill the two ends of the high-rib structure, making the top of the high-rib structure tend to be flat; at the same time, the seven outer protrusions on the upper surface of the pre-pressed part continue to be filled and formed, and the center of the outer protrusion is formed inward, so that the outer protrusion forms a circular cup shape, and the height of the outer protrusion increases to 33.5mm; during the pre-pressing process in step S3, the arc-shaped top of the high-rib structure on the lower surface of the double-sided rough-pressed part is first pressed back by the mold, then fills the outer part of the high-rib structure, and finally fills the inner part of the high-rib structure.

[0013] Preferably, in the final pressing process of step S4, the high-rib structure is filled and formed sequentially from the side near the edge of the pre-pressed part to the side near the center of the pre-pressed part, and finally the second annular rib is filled and formed.

[0014] Preferably, the forging is made of 2040 aluminum alloy, the die material is 5CrNiMo, the billet forming temperature of each process is between 420℃ and 450℃, the die temperature is between 350℃ and 400℃, and the forming speed is between 2mm / s and 5mm / s.

[0015] Preferably, the molds used in steps S2 to S4 are all composed of an upper mold and a corresponding lower mold. The molds in each step are initially positioned using a pair of guide pillars and guide sleeves. The molds are also provided with a diamond-shaped locking structure to prevent misalignment between the molds. At the same time, the molds also include ejector pins. The ejector pins and the corresponding lower molds are supported by inclined contact surfaces to further ensure the forming accuracy of the ejector pin positions.

[0016] Preferably, in steps S1 to S4, the underpressure value of the mold is set to 0 mm.

[0017] Preferably, the molds used in steps S3 and S4 are provided with a cylindrical inner flash structure.

[0018] Preferably, after each process from step S1 to step S4 is completed, the forging is trimmed, and after each process from step S2 to step S4 is completed, the corresponding position of the cylindrical flash is also removed.

[0019] The precision forging method for passenger aircraft aluminum alloy piston seats described in this invention achieves the following beneficial effects: This invention provides a precision forming method for passenger aircraft piston seats, which solves folding defects by rationally planning the metal filling sequence at high-rib positions and improves forming accuracy by optimizing the mold structure. The piston seat forging is formed using a forging process of first-stage rough pressing, second-stage rough pressing, pre-pressing, and final pressing. The high-rib structure is initially formed using a flat plate, and then the final forming sequence of the high-rib structure is controlled to be from the middle to the ends and from the outside in, thus avoiding folding defects in the high-rib structure. Simultaneously, to address the high precision requirements of the forging, diamond-shaped locking mechanisms are used in the upper and lower dies of each process to prevent misalignment between the dies, while the ejector pin position uses an inclined bearing surface to prevent misalignment between the ejector pin and the die. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the metal flow state during the first heat pressing preforming in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the metal flow state during the second heat pressing preforming in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the metal flow state during pre-pressing in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the metal flow state during final pressing in an embodiment of the present invention;

[0025] Figure 6 A schematic diagram of the metal flow state during final pressing without using the forging process provided by this invention.

[0026] Figure 7 This is a schematic diagram of the metal flow state that occurs when a flat plate is not used as the upper die during the first pressing pre-forming process.

[0027] Figure 8 This is a schematic diagram of the final pressing die structure used in an embodiment of the present invention;

[0028] Figure 9 This is a schematic diagram of the upper and lower surface structures of the double-sided pressed part formed according to an embodiment of the present invention;

[0029] Figure 10 This is a schematic diagram of the upper and lower surface structures of the pre-compressed part formed according to an embodiment of the present invention;

[0030] Figure 11 This is a schematic diagram of the upper and lower surface structures of the forged part formed according to an embodiment of the present invention.

[0031] In the figure, 1 is the initial blank, 2 is the double-sided blank, 3 is the pre-pressed part, 4 is the die forging part, 5 is the flat anvil, 6 is the blank pressing upper die, 7 is the blank pressing lower die, 8 is the pre-pressing upper die, 9 is the pre-pressing lower die, 10 is the final pressing upper die, 11 is the final pressing lower die, 12 is the lock, 13 is the guide sleeve, 14 is the inclined contact surface, 15 is the central protrusion structure, 16 is the outer protrusion structure, 17 is the circular inner groove, 18 is the high rib structure, 19 is the first central circular groove, 20 is the second central circular groove, 21 is the outer circular groove, 22 is the inclined surface structure, 23 is the first annular rib, 24 is the second annular rib, and 25 is the hemispherical protrusion. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] Example

[0034] Depend on Figure 11As shown, the forged part 4 of the aluminum alloy piston seat for passenger aircraft includes an upper surface and a lower surface. The upper surface includes a first central circular groove 19, seven sets of inclined surface structures 22, and seven outer circular grooves 21. The lower surface includes seven evenly distributed hemispherical protrusions 25, a second central circular groove 20, a second annular rib 24 surrounding the second central circular groove 20, and seven sets of high rib structures 18. The positions of the first central circular groove 19 and the second central circular groove 20 correspond to each other on the upper and lower surfaces of the forging part 4. The positions of the outer circular grooves 21 and the hemispherical protrusions 25 correspond to each other on the upper and lower surfaces of the forging part 4. The positions of the inclined surface structures 22 and the high rib structures 18 correspond to each other on the upper and lower surfaces of the forging part 4. Each set of high rib structures 18 connects to a hemispherical protrusion 25 and a second central circular groove 20. Each set of inclined surface structures 22 connects to an outer circular groove 21 and a first annular rib 23 surrounding the first central circular groove 19. The forming difficulty mainly lies in the forming process of the multiple sets of high-rib structures 18 on the lower surface of the forging 4. The cross-section formed by the high-rib structure 18 is the largest cross-sectional area in the forging 4, requiring more metal filling and a more reasonable metal filling sequence. The main characteristics of the high-rib structure 18 are its high rib height, thin width, small draft angle, and non-machined area. Considering its position distribution and surrounding structure, the most difficult area for metal filling of each set of high-rib structures 18 is concentrated in the center of the high-rib structure 18, because this position is formed last. In conventional processing, the metal filling the center of the high-rib structure 18 is mainly filled by the excess metal after the filling of the hemispherical protrusion 25 on the lower surface of the forging 4 corresponding to the position of the high-rib structure 18, the inclined structure 22 on the upper surface of the forging 4 corresponding to the position of the high-rib structure 18, and the second annular rib 24. Therefore, typical confluence folding defects and incomplete metal filling are very likely to form at this position.

[0035] like Figure 6 and Figure 7 As shown, when forging part 4 using conventional processing technology, the high-rib structure 18 of the forging part 4 is prone to folding defects during the forging process. Because the upper and lower surfaces of the rough forging part are not formed separately, and especially because the preliminary shape of the high-rib structure 18 is not pre-formed, the center (middle) position at the top of the high-rib structure 18 becomes the last forming position. At this point, the metal forming sequence of the high-rib structure 18 flows from the inner, outer, and upper sides relative to each group of high-rib structures 18 towards the top position of the high-rib structure 18, which poses a significant risk of folding defects. During final pressing, the metal filling of the high-rib structure 18 is as follows... Figure 7 As shown. Due to the lack of a reasonable planning of the forming sequence of the high-rib structure 18, according to the principle of least resistance, the metal first fills the upper, inner and outer sides of the high-rib structure 18, and finally fills the middle position of the top of the high-rib structure 18, thus forming a folding defect at that position.

[0036] To address the problem of folding defects forming in the high-rib structure 18 of the aforementioned die forging 4 during the forging process, this invention provides a precision forging method for an aluminum alloy piston seat for passenger aircraft, which will now be described in detail through embodiments.

[0037] In this embodiment, the forging 4 of the aluminum alloy piston seat of the passenger aircraft is made of 2040 aluminum alloy, and its maximum external dimensions are 498mm×430mm×83mm. The height of the high rib structure 18 on the forging 4 is 50mm, the width is 7.5mm, and the draft angle is 3°.

[0038] In this embodiment, the die material used in the forging process is 5CrNiMo, including a rough pressing die, a pre-pressing die, and a final pressing die. All dies are composed of an upper die and a corresponding lower die. The rough pressing die includes a rough pressing upper die 6 and a rough pressing lower die 7. The pre-pressing die includes a pre-pressing upper die 8 and a pre-pressing lower die 9. The final pressing die includes a final pressing upper die 10 and a final pressing lower die 11.

[0039] like Figure 8 As shown, in steps S2 to S4, each mold uses paired guide pillars and guide sleeves 13 for initial positioning. A diamond-shaped locking structure 12 is also provided on the mold to prevent misalignment between molds. In this embodiment, the locking structure 12 has dimensions of 1000mm × 1000mm, with a height of 40mm in the roughing mold and 35mm in both the pre-pressing and final pressing molds. The mold also includes an ejector pin, which shares a bearing surface 14 with the corresponding lower mold, further ensuring the forming accuracy of the ejector pin position.

[0040] like Figure 1 As shown, the forging method includes the following steps:

[0041] Step S1: As Figure 2As shown, the initial blank 1 undergoes a first-stage pre-forming process to obtain a single-sided pre-formed part. In this embodiment, the initial blank 1 is a disc-shaped blank. The upper die used in the first-stage pre-forming process is a flat anvil 5 with a flat plate structure, and the lower die is a pre-forming lower die 7. The pre-forming lower die 7 is provided with a ribbed cavity structure for forming high-rib structures 18. The upper surface of the single-sided pre-formed part is a planar structure, and a circular inner groove 17 is formed in the middle of the lower surface. The circular inner groove 17 contains high-rib structures 18 formed radially. There are seven high-rib structures 18, evenly spaced within the circular inner groove 17. Because the high-rib structure 18 has a relatively high height, small width, and small draft angle and corner radius, in order to ensure the positioning of each process and avoid folding defects on the side of the rib structure, after the first pressing process, the high-rib structure 18 on the lower surface of the single-sided pressing part, except for the top shape and height value, has the same structural features such as position, width, and draft angle as the high-rib structure 18 on the lower surface of the forging part 4 obtained after the final pressing in step S4. After the first pressing pre-forming process, the height of the side of each group of high-rib structures 18 near the center of the single-sided pressing part is lower than the height of the side near the edge of the single-sided pressing part. The overall height of the high-rib structure 18 is 35mm, and a raised arc-shaped structure is formed in the middle of the top of each group of high-rib structures 18. The height of the raised part of the arc-shaped structure is 5mm.

[0042] Figure 2 The diagram shows the metal flow on the cross section of the high-rib structure 18 during the first pre-forming process. Since the upper mold of the forming die is a flat plate structure and the lower mold only forms the high-rib structure 18, the upper side of the high-rib structure 18 is subjected to a uniform downward pressure during forming. The metal mainly flows in a single direction from the inside to the outside of the high-rib structure 18, thus avoiding the generation of folding defects.

[0043] Step S2: As Figure 3 and Figure 9As shown, a second pressing pre-forming process is performed on a single-sided pressed part to obtain a double-sided pressed part 2. The upper die used in the second pressing process is a pressing upper die 6, and the lower die used is the same as the pressing lower die 7 used in step S1. The pressing upper die 6 is provided with a forming cavity for forming the upper surface structure of the single-sided pressed part. During the second pressing process, the shape of the high-rib structure 18 on the lower surface of the single-sided pressed part remains unchanged. After the second pressing process, a frustum-shaped central protrusion structure 15 is formed on the upper surface of the double-sided pressed part 2. The central protrusion structure 15 is designed as a flat-topped frustum shape because it is easier to form during the pressing pre-forming process. The diameter of the central protrusion structure 15 is φ124mm, and its height is 15mm. Seven frustum-shaped outer protrusion structures 16 are uniformly formed around the central protrusion structure 15. The outer contour diameter of the outer protrusion structure 16 is φ70mm, and its height is 12.5mm. The second pre-forming process mainly shapes the upper surface of the forged part. The lower die is the same as the lower die 7 used in step S1, and the flat anvil 5 is replaced with the upper die 6 to form the upper surface structure of the single-sided forged part. At this time, the central protrusion structure 15, which corresponds to the first annular rib 23 on the upper surface, is a frustum-shaped structure, and the surrounding area has outer protrusion structures 16 corresponding to the outer circular grooves 21 of the seven cup-shaped structures on the upper surface of the forging part 4.

[0044] Step S3: As Figure 10 As shown, the double-sided pressed part 2 is pre-pressed to obtain a pre-pressed part 3 with a shape closer to that of the die forging part 4. During the pre-pressing process, the upper surface structure of the double-sided pressed part 2 is further shaped, and the high rib structure 18 on the lower surface of the double-sided pressed part 2 is also locally shaped. After the pre-pressing process is completed, the arc-shaped top structure of the high rib structure 18 is pressed down to fill the two ends of the high rib structure 18, making the top of the high rib structure 18 tend to be flat. At the same time, the seven outer protrusions 16 on the upper surface of the pre-pressed part 3 continue to be filled and shaped, and the center of the outer protrusions 16 is concave, so that the outer protrusions 16 form a circular cup shape, and the height of the outer protrusions 16 increases to 33.5mm. During the pre-pressing process in step S3, the arc-shaped top structure of the high rib structure 18 on the lower surface of the double-sided pressed part 2 is first pressed back by the mold, then the outer part of the high rib structure 18 is filled, and finally the inner part of the high rib structure 18 is filled.

[0045] like Figure 4As shown, after the two pre-forming processes, there is a raised arc-shaped structure with a height of 5mm at the top center of the high-rib structure 18. This pre-stores a large amount of metal in the most difficult-to-fill part of the high-rib structure 18. During pre-forming, this part and the outer part of the high-rib structure 18 are filled simultaneously. Then, the annular rib between the high-rib structure 18 and the pre-formed part, located on the inner side of the arc-shaped structure, is filled. The metal flow at the location of the high-rib structure 18 is as follows: Figure 4 As shown. After the high rib structure 18 is formed on the lower surface of the pre-pressed part 3, the high rib structure 18 exhibits the characteristics of being short on the inside and high on the outside, which rationally plans the metal flow direction of the high rib structure 18 during the next final pressing.

[0046] Step S4: As Figure 11 As shown, the pre-pressed part 3 is subjected to final pressing forming to obtain the die forging part 4 with a precision integral structure. During the final pressing forming process, the high-rib structure 18 is filled and formed sequentially from the side near the edge of the pre-pressed part 3 to the side near the center of the pre-pressed part 3, until the second annular rib 24 is finally filled and formed.

[0047] like Figure 5 As shown, the final pressing process mainly involves the final shaping of the pre-pressed part 3. Besides the final shaping of the upper surface and the cup-shaped protrusions of the pre-pressed part 3, the high-rib structure 18 on the lower surface of the pre-pressed part 3 also needs final filling. The metal flow at the location of the high-rib structure 18 is as follows... Figure 5 As shown. Because the high rib structure 18 of the pre-pressed part 3 has the characteristics of being low inside and high outside, the metal filling sequence of the high rib structure 18 during the final pressing is from the outside to the inside. The last filling position of the die forging part 4 is mainly the second annular rib 24 at the center of the lower surface of the die forging part 4.

[0048] In steps S1 to S4 of this embodiment, the billet forming temperature is between 420°C and 450°C, the die temperature is between 350°C and 400°C, and the forming speed is between 2 mm / s and 5 mm / s. The underpressure value of the die is set to 0 mm. If the underpressure of the forging is consistently greater than 0 mm during final pressing due to elastic deformation of the die, the die is appropriately lowered according to the height of the forging. The dies used in steps S3 and S4 are equipped with a cylindrical inner flash structure to accommodate excess metal. After each step from S1 to S4, the forging is trimmed, and after each step from S2 to S4, the corresponding positions of the cylindrical flash are also removed.

[0049] The aforementioned precision forging method for aluminum alloy piston seats for passenger aircraft optimizes the forming process of non-machining high-rib structure areas while ensuring the qualified forming of the forging. This significantly reduces the risk of folding defects at the top center of the high-rib structure. These folding defects are primarily caused by the forging structure itself. To address this issue, the present invention redesigns the forging process based on the metal flow characteristics at the location of the high-rib structure. By altering the metal filling sequence at the high-rib structure location, the folding defect is avoided. The specific forming process flow is as follows: Figure 1 As shown, the pre-forming process is first divided into a first-stage pre-forming process and a second-stage pre-forming process. In particular, a flat anvil with a flat structure is used to independently form the rough shape of the high rib structure on the lower surface and the rough shape of the upper surface structure of the part in sequence. Then, in the pre-forming and final-forming processes, the top middle position of the high rib structure is filled first, then the two sides of the high rib structure are filled, and metal is filled from the outside to the inside of the high rib structure. This completely avoids the situation where the metal in the high rib structure position flows into one position from three directions.

[0050] The above embodiments are merely illustrative examples to clearly illustrate the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for precision forging of aluminum alloy piston seats for passenger aircraft, characterized in that... The method includes the following steps: Step S1: Perform a first-stage pre-forming process on the initial blank to obtain a single-sided pre-formed part; the upper die used in the first-stage pre-forming process is a flat upper die, and the lower die used is a pre-forming lower die. The pre-forming lower die is provided with a rib cavity structure for forming high-rib structures; the upper surface of the single-sided pre-formed part is a planar structure, and a circular inner groove is formed in the middle of the lower surface. The circular inner groove contains high-rib structures formed in the radial direction. There are 7 groups of high-rib structures, which are arranged at equal intervals in the circular inner groove. Step S2: Perform a second pressing pre-forming process on the single-sided pressed part to obtain a double-sided pressed part; the upper die used in the second pressing process is a pressing upper die, and the lower die used is the same as the pressing lower die used in step S1. The pressing upper die is provided with a forming cavity for forming the upper surface structure of the single-sided pressed part; the shape of the high rib structure on the lower surface of the single-sided pressed part does not change during the second pressing process. Step S3: Perform pre-pressing forming on the double-sided blank to obtain a pre-pressed part with a shape closer to that of a forging; During the pre-pressing process, the upper surface structure of the double-sided pressed part is further shaped, and the high rib structure on the lower surface of the double-sided pressed part is also locally shaped. Step S4: Perform final pressing forming on the pre-pressed part to obtain a die forging with a precision integral structure.

2. The precision forging method for aluminum alloy piston seats of passenger aircraft according to claim 1, characterized in that, The initial blank used in step S1 is a disc-shaped blank. After the first pressing is completed, the position, width, and draft angle of the high rib structure on the lower surface of the single-sided pressed part are the same as the high rib structure on the lower surface of the die forging obtained after step S4. The height of the high rib structure on the side near the center of the single-sided pressed part is lower than the height on the side near the edge of the single-sided pressed part, and a raised arc top structure is formed in the middle of the top of each group of high rib structures. The height of the raised part of the arc top structure is 5mm.

3. The precision forging method for aluminum alloy piston seats of passenger aircraft according to claim 2, characterized in that, After step S2 is completed, a frustum-shaped central protrusion structure is formed on the upper surface of the double-sided pressed part, and seven frustum-shaped outer protrusion structures are uniformly formed around the central protrusion structure. The diameter of the central protrusion structure is ϕ124mm and the height is 15mm, and the outer contour diameter of the outer protrusion structure is ϕ70mm and the height is 12.5mm.

4. The precision forging method for aluminum alloy piston seats of passenger aircraft according to claim 3, characterized in that, After step S3 is completed, the arched top structure of the high rib structure is pressed down to fill the two ends of the high rib structure, making the top of the high rib structure tend to be flat; at the same time, the seven outer protrusions on the upper surface of the pre-pressed part continue to be filled and formed, and the center of the outer protrusions is recessed, so that the outer protrusions form a circular cup shape, and the height of the outer protrusions increases to 33.5mm; during the pre-pressing process in step S3, the arched top structure of the high rib structure on the lower surface of the double-sided rough pressed part is first pressed back by the mold, then fills the outer part of the high rib structure, and finally fills the inner part of the high rib structure.

5. The precision forging method for aluminum alloy piston seats of passenger aircraft according to claim 4, characterized in that, During the final pressing process in step S4, the high-rib structure is filled and formed sequentially from the side near the edge of the pre-pressed part to the side near the center of the pre-pressed part, and finally the annular rib located at the center of the lower surface of the die forging is filled and formed.

6. The method for precision forging of aluminum alloy piston seats for passenger aircraft according to any one of claims 1 to 5, characterized in that, The forging is made of 2040 aluminum alloy, the die material is 5CrNiMo, the billet forming temperature of each process is between 420℃ and 450℃, the die temperature is between 350℃ and 400℃, and the forming speed is between 2mm / s and 5mm / s.

7. The method for precision forging of aluminum alloy piston seats for passenger aircraft according to claim 6, characterized in that, The molds used in steps S2 to S4 are all composed of an upper mold and a corresponding lower mold. The molds in each step are initially positioned using a pair of guide pillars and guide sleeves. The molds are also equipped with a diamond-shaped locking structure to prevent misalignment between the molds. At the same time, the molds also include ejector pins. The ejector pins and the corresponding lower molds are supported by inclined contact surfaces to further ensure the forming accuracy of the ejector pin positions.

8. The method for precision forging of aluminum alloy piston seats for passenger aircraft according to claim 7, characterized in that, In steps S1 to S4, the underpressure value of the mold is set to 0mm.

9. The precision forging method for aluminum alloy piston seats of passenger aircraft according to claim 8, characterized in that, The molds used in steps S3 and S4 are both equipped with a cylindrical inner flash structure.

10. The method for precision forging of aluminum alloy piston seats for passenger aircraft according to claim 9, characterized in that, After each process from step S1 to step S4 is completed, the forging must be trimmed. After each process from step S3 to step S4 is completed, the corresponding position of the cylindrical flash must also be removed.

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