A split forming die, a taper ring forging and a forming method thereof

Abstract

The present application relates to the technical field of forging preparation, in particular to a forming die, a conical ring forging and a forming method thereof, the forming die comprises a punch, a plurality of annular working slopes are arranged on the outer surface of the punch; the working slopes are distributed along the axial direction on the outer surface of the punch, and a friction-reducing slope is formed between adjacent working slopes; the friction-reducing slope is recessed inward from the outer surface of the punch, and the recessed depth is consistent along the radial direction. By arranging the friction-reducing slope on the outer surface of the punch, the contact area between the punch and the annular blank is effectively reduced, and then the height of the annular blank increased to compensate for the height reduction is reduced, the feeding weight is reduced, and the material utilization rate is improved.

Description

Technical Field

[0001] This invention relates to the field of forging technology, and in particular to a bending forming mold, a conical ring forging, and a forming method thereof. Background Technology

[0002] Conical ring forgings are a type of rotating forging with inconsistent diameters at both ends, widely used in aerospace, automotive manufacturing, and construction machinery industries. For example... Figure 1 As shown, when producing this type of forging, a punch is usually required for bending or forming operations. In the traditional bending process, the design of forging dimensions must follow the principle that the volumes at the top and bottom ends of the forging are equal, that is, satisfying: D1² - d1² = D2² - d2².

[0003] In actual production, friction exists between the punch and the annular billet, causing the billet to flow simultaneously in both the diameter and height directions during bending, resulting in a lower forging height. As bending continues, the contact area between the annular billet and the punch increases, and the contact surface temperature drops sharply, leading to increased rigidity and difficulty in deformation of the billet. If pressure continues to be applied at this point, upsetting will occur at the lower part of the annular billet, causing the forging height to exceed tolerances.

[0004] To ensure that the produced forgings meet dimensional requirements, height compensation is necessary to obtain the final annular billet height H = H0 + ΔH. Typically, the height compensation ΔH is related to the angle θ between the forging's generatrix and the vertical direction, as well as the length of the generatrix: the longer the generatrix, the larger the contact area between the die and the annular billet, and the greater the height reduction; the larger θ, the greater the vertical force on the annular billet, resulting in a greater height reduction and a larger compensation amount.

[0005] When the product dimensions are constant, θ and the forging height H are both constant. To reduce the weight of the forging, decrease raw material consumption, and improve material utilization, a technical solution that can reduce the amount of shortening during the forging process is urgently needed. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned problems existing in the prior art and to provide a bending forming mold, a conical ring forging and its forming method.

[0007] In a first aspect, the present invention provides a forming die for forming a tapered ring forging, the forming die including a punch, wherein a plurality of annular working inclined surfaces are provided on the outer surface of the punch; the working inclined surfaces are distributed axially at intervals on the outer surface of the punch, and a friction-reducing inclined surface is formed between adjacent working inclined surfaces; the friction-reducing inclined surface is recessed inward from the outer surface of the punch, and the recess depth remains consistent along the radial direction.

[0008] Preferably, the conical ring forging is a rotating forging with an upper diameter larger than the lower diameter, and the small end of the punch is the lower end, the large end is the upper end, and the upper diameter is larger than the lower diameter.

[0009] Preferably, there are 3-13 friction-reducing inclined surfaces, and the number of friction-reducing inclined surfaces is determined according to the generatrix length of the conical ring forging.

[0010] Preferably, the difference between the upper and lower diameters of the different anti-friction inclined planes is the same, satisfying D. Mm -D Sm =D M(m+1) -D S(m+1) D Sm Let D be the diameter of the lower end of the m-th friction-reducing inclined plane. Mm Let D be the diameter of the upper end of the m-th friction-reducing inclined plane. S(m+1) Let D be the diameter of the lower end of the (m+1)th friction-reducing inclined plane. M(m+1) Let be the diameter of the upper end of the (m+1)th friction-reducing inclined plane. Through the above technical solution, the friction-reducing inclined planes have a consistent drop in the diameter direction. In this invention, the lower end of the friction-reducing inclined plane refers to the end face closest to the small end of the punch, and the upper end of the friction-reducing inclined plane refers to the end face closest to the large end of the punch.

[0011] More preferably, the difference between the diameter of the lowest point of the inwardly concave anti-friction slope and the diameter of the upper or lower end is the same, satisfying D. Lm -D Sm =D L(m+1) -D S(m+1) And D Mm -D Lm =D M(m+1) -D L(m+1) D Lm Let D be the diameter of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. L(m+1) It is the diameter of the lowest point of the inward concavity of the (m+1)th friction-reducing inclined plane.

[0012] Preferably, the difference between the height of the upper end and the height of the lower end of the different friction-reducing inclined surfaces is the same, satisfying H Mm -H Sm =H M(m+1) -H S(m+1) H Sm H is the height of the lower end of the m-th friction-reducing inclined plane. Mm H is the height of the upper end of the m-th friction-reducing inclined plane. S(m+1) H is the height of the lower end of the (m+1)th friction-reducing inclined plane. M(m+1)The height is the upper end of the (m+1)th friction-reducing inclined surface. In this invention, the height refers to the distance between the upper or lower end of the friction-reducing inclined surface and the small end of the punch. Through the above technical solution, the friction-reducing inclined surfaces are uniformly distributed along the height direction of the punch.

[0013] More preferably, the difference between the height of the lowest point of the inwardly concave anti-friction slope and the diameter of the upper end or the height of the lower end is the same, satisfying H Lm -H Sm =H L(m+1) -H S(m+1) And H Mm -H Lm =H M(m+1) -H L(m+1) H Lm H is the height of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. L(m+1) It is the height of the lowest point of the (m+1)th friction-reducing inclined plane that is concave inward.

[0014] Preferably, the angle between the generatrix of the friction-reducing inclined plane and the axial direction is greater than 0°, satisfying: D Lm >D Sm D Lm Let D be the diameter of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. Sm Let be the diameter of the lower end of the m-th friction-reducing inclined plane.

[0015] Preferably, the punch has a working inclined surface on both the small end and the large end of its outer surface.

[0016] Preferably, the friction-reducing inclined surface is not provided on the side of the punch closest to the small end and within a 50mm range of the generatrix length, thus satisfying the requirement that... ≥50, where d1 is the small end diameter of the punch, D S1 H is the diameter of the small end of the first friction-reducing inclined plane closest to the small end of the punch. S1 The height of the small end of the first friction-reducing inclined plane closest to the small end of the punch.

[0017] Preferably, the friction-reducing inclined surface is not provided within a 15mm drop range of the small end outer diameter of the punch, satisfying the following: ≥15, where d1 is the small end diameter of the punch, D S1 It is the diameter of the small end of the first friction-reducing inclined plane closest to the small end of the punch.

[0018] Preferably, the generatrix length of each of the working inclined planes is ≥60mm, satisfying: ≥60, where D Sm Let D be the diameter of the lower end of the m-th friction-reducing inclined plane. M(m-1) H is the diameter of the upper end of the (m-1)th friction-reducing inclined plane. SmH is the height of the lower end of the m-th friction-reducing inclined plane. M(m-1) It is the height of the upper end of the (m-1)th friction-reducing inclined plane.

[0019] Preferably, each generatrix segment between adjacent friction-reducing inclined surfaces is provided with a rounded transition, and the radius of the rounded corner is configured so as not to scratch the forging body.

[0020] Preferably, the molding die further includes a lower anvil and an upper anvil.

[0021] In a second aspect, the present invention provides a method for forming a tapered ring forging, wherein a forming die for bending and shortening the tapered ring forging is used in the forming process, comprising the following steps:

[0022] The annular billet is placed on the lower anvil, and the punch is inserted into the annular billet; The upper anvil moves downward, contacts the punch, and drives the punch downward to shape the annular blank.

[0023] Preferably, the forming method includes the following steps: Step S1: Heat the sawn bar to the forging temperature and hold it at that temperature. Then, upset and punch the bar after holding it at that temperature to obtain a ring billet. Step S2: After heating the ring billet, it is placed on the lever and then on the frame. Under the drive of the press, pressure is applied to the ring billet to reduce the wall thickness and expand the inner and outer diameters, thus obtaining the ring billet. Step S3: After heating the annular billet, place it on the lower anvil, then insert the punch into one end of the annular billet. Under the drive of the press, the upper anvil applies pressure to the punch, causing the punch to be pressed into the annular billet to obtain an irregular annular billet. Step S4: Heat the irregular ring billet, place the mandrel die into the irregular ring billet, and under the drive of the ring rolling mill, the mandrel die applies pressure to the irregular ring billet. The mandrel die and the main roll die roll the irregular ring billet to obtain a ring forging.

[0024] In a third aspect, the present invention provides a conical ring forging, which is manufactured using the forming method of the conical ring forging described above.

[0025] Compared with the prior art, the beneficial effects of the present invention include: 1. This invention provides a forming die for bending tapered ring forgings. By setting a friction-reducing inclined surface on the outer surface of the punch, the contact area between the punch and the ring blank is effectively reduced. The reduced contact area alters the unit pressure distribution on the actual contact surface, lowering the frictional resistance to radial metal flow and making it easier for the metal to flow in the diameter direction rather than the height direction. Therefore, the amount of height reduction ΔH of the ring blank during bending is significantly reduced, thereby reducing the increase in ring blank height to compensate for the height reduction, lowering the feed weight, and improving material utilization.

[0026] 2. This invention provides a forming die for bending tapered ring forgings. By using a friction-reducing inclined surface, the contact area between the punch and the ring blank is reduced, slowing down the temperature drop rate of the ring blank's contact surface. This allows the ring blank to maintain good plasticity during bending, reducing deformation resistance and promoting uniform metal flow, thus avoiding lower upsetting defects caused by localized low temperatures. By reducing the bending draw and its fluctuations, the forging height is made closer to the theoretical value, improving the dimensional accuracy and consistency of the forgings and reducing the scrap rate.

[0027] 3. The friction-reducing punch of the present invention only requires machining friction-reducing inclined surfaces on the outer surface of a traditional punch, without the need to modify existing equipment, resulting in low processing costs and easy promotion and application. The number, depth, spacing and other parameters of the friction-reducing inclined surfaces can be flexibly adjusted according to the length of the forging generatrix, thus exhibiting good adaptability. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of a tapered ring forging, where D2 and d2 are the outer and inner diameters of the upper end, respectively, and D1 and d1 are the outer and inner diameters of the lower end, respectively. Figure 2 This is a schematic diagram of the structure of the friction-reducing punch provided in an embodiment of the present invention; Figure 3 This is a partial schematic diagram of the friction-reducing punch provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the annular blank being placed on the lower anvil in the bending process of an embodiment of the present invention; Figure 5 This is a schematic diagram of the punch being placed into the annular blank during the bending process in an embodiment of the present invention; Figure 6 This is a schematic diagram of the upper anvil pressing down on the breaking shape in an embodiment of the present invention; Figure 7 This is a schematic diagram of the bent shape according to an embodiment of the present invention; Marked in the image: 1-Punch, 11-Friction-reducing inclined plane, 12-Working inclined plane, 2-Upper anvil, 3-Lower anvil, 4-Ring billet. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0030] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0031] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are set as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when set in a "horizontal," "vertical," "suspended," "parallel," or "coaxial" direction, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1 mm, preferably within 0.2-0.5 mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0032] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0033] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0034] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0035] This invention provides a forming die for shaping tapered ring forgings, the forming die including a punch, such as... Figure 2 The outer surface of the punch is provided with a plurality of annular working inclined surfaces; the working inclined surfaces are distributed axially at intervals on the outer surface of the punch, and a friction-reducing inclined surface is formed between adjacent working inclined surfaces; the friction-reducing inclined surface is recessed inward from the outer surface of the punch, and the recess depth is consistent along the radial direction.

[0036] like Figure 1 As shown, the conical ring forging is a rotating forging with an upper diameter larger than its lower diameter. The small end of the punch is the lower end, and the large end is the upper end. The outer diameter D2 of the upper end is larger than the outer diameter D1 of the lower end. When producing this type of forging, a punch is needed for bending or forming the blank. When designing the dimensions of the ring forging, the principle that the volumes of the upper and lower ends of the ring forging are equal should be followed, i.e., the following conditions must be met: D1 2 -d1 2 =D2 2 -d2 2 The theoretical height H of the annular billet before shaping is calculated using the following formula: H=4V 体 / [π(D0 2 - d0 2 )] Where V 体 Let D0 be the outer diameter of the annular billet and d0 be the inner diameter of the annular billet. In actual production, friction exists between the punch and the annular billet, causing the billet to flow simultaneously in both the diameter and height directions during bending, resulting in a lower forging height. To ensure the produced forging meets dimensional requirements, height compensation is necessary, yielding the final annular billet height: H = H0 + ΔH, where ΔH is the height compensation amount.

[0037] Compared with a conventional punch die, the friction-reducing punch of the present embodiment has a plurality of friction-reducing slopes distributed on the outer contour surface of the punch, the number of the friction-reducing slopes is 3-13, and the number of the friction-reducing slopes is determined according to the generatrix length of the conical ring forging. For a conical ring forging with a shorter generatrix length (e.g., L≤120mm), fewer friction-reducing slopes (e.g., 3-5) can be provided to ensure that the punch has sufficient structural strength; for a conical ring forging with a medium generatrix length (e.g., 120mm<L≤200mm), an appropriate number of friction-reducing slopes (e.g., 6-9) can be provided to achieve a balance between the friction reduction effect and the punch strength; for a conical ring forging with a longer generatrix length (e.g., L>200mm), more friction-reducing slopes (e.g., 10-13) can be provided to fully reduce the friction resistance during the shaping process and effectively control the height reduction amount. The number of slopes can be increased or decreased according to actual production conditions to meet the production requirements of conical ring forgings of different specifications.

[0038] Specifically in the present embodiment, working slopes, friction-reducing slopes, working slopes, friction-reducing slopes, working slopes, friction-reducing slopes, working slopes, friction-reducing slopes and working slopes are sequentially distributed from bottom to top on the outer contour surface of the punch.

[0039] In some embodiments, the difference between the upper end diameter and the lower end diameter of different said friction-reducing slopes is the same, satisfying D Mm -D Sm =D M(m+1) -D S(m+1) , wherein D Sm is the diameter of the lower end of the m-th friction-reducing slope, D Mm is the diameter of the upper end of the m-th friction-reducing slope, D S(m+1) is the diameter of the lower end of the (m+1)-th friction-reducing slope, D M(m+1) is the diameter of the upper end of the (m+1)-th friction-reducing slope. Through the above technical solution, the diameter direction drop of the friction-reducing slopes is consistent, so that the contact area between the punch and the annular blank is uniformly reduced at each slope, and local contact stress concentration is avoided. In the present invention, the lower end of the friction-reducing slope refers to the end face of the friction-reducing slope closest to the small end of the punch, and the upper end of the friction-reducing slope refers to the end face of the friction-reducing slope closest to the large end of the punch.

[0040] More preferably, the difference between the diameter at the lowest position of the inward concave of the friction-reducing slope and the upper end diameter or the lower end diameter is the same, satisfying D Lm -D Sm =D L(m+1) -D S(m+1) and D Mm -D Lm =D M(m+1) -D L(m+1) , wherein D LmLet D be the diameter of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. L(m+1) Let be the diameter of the lowest point of the (m+1)th friction-reducing inclined plane that is concave inwards. For example... Figure 3 As shown, D L1 -D S1 =D L2 -D S2 And D M1 -D L1 =D M2 -D L2 D L2 -D S2 =D L2 -D S2 And D M2 -D L2 =D M3 -D L3 D L3 -D S3 =D L4 -D S4 And D M3 -D L3 =D M4 -D L4 .

[0041] In some embodiments, the difference between the height of the upper end and the height of the lower end of different friction-reducing inclined planes is the same, satisfying H Mm -H Sm =H M(m+1) -H S(m+1) H Sm H is the height of the lower end of the m-th friction-reducing inclined plane. Mm H is the height of the upper end of the m-th friction-reducing inclined plane. S(m+1) H is the height of the lower end of the (m+1)th friction-reducing inclined plane. M(m+1) The height is the upper end of the (m+1)th friction-reducing inclined surface. Through the above technical solution, the friction-reducing inclined surfaces are evenly distributed along the height direction of the punch, ensuring a stable friction-reducing effect at each stage of the entire bending process. In this invention, height refers to the distance between the upper or lower end of the friction-reducing inclined surface and the small end of the punch.

[0042] More preferably, the difference between the height of the lowest point of the inwardly concave anti-friction slope and the diameter of the upper end or the height of the lower end is the same, satisfying H Lm -H Sm =H L(m+1) -H S(m+1) And H Mm -H Lm =H M(m+1) -H L(m+1) H Lm H is the height of the lowest point of the inward concavity of the m-th friction-reducing inclined plane.L(m+1) This is the height of the lowest point of the (m+1)th friction-reducing inclined plane that is concave inwards. For example... Figure 3 As shown, H L1 -H S1 =H L2 -H S2 And H M1 -H L1 =H M2 -H L2 H L2 -H S2 =H L2 -H S2 And H M2 -H L2 =H M3 -H L3 H L3 -H S3 =H L4 -H S4 And H M3 -H L3 =H M4 -H L4 .

[0043] In some embodiments, the angle between the generatrix of the friction-reducing inclined plane and the axial direction is greater than 0°, satisfying: D Lm >D Sm D Lm Let D be the diameter of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. Sm Let be the diameter of the lower end of the m-th friction-reducing inclined plane. This feature ensures that each inclined plane has a positive angle relative to the vertical direction, so that during the bending process, the inclined plane can guide the annular billet metal to flow in the diameter direction, rather than being stretched or upset in the vertical direction.

[0044] In some embodiments, working inclined surfaces are provided on the outer surfaces of the punch near the small end and the large end. The cross section of the working inclined surface along the axial direction is a straight segment. Each generatrix segment between adjacent friction-reducing inclined surfaces is provided with a rounded transition. The radius of the rounded corner is configured to avoid scratching the forging body, thereby avoiding sharp corner transitions from causing scratches or stress concentration on the surface of the forging during the bending process and ensuring the surface quality of the forging.

[0045] In some embodiments, the friction-reducing inclined surface is not provided on the outer surface of the punch near the small end, within a 50mm range of the generatrix length, to satisfy... ≥50, where d1 is the small end diameter of the punch, D S1 H is the diameter of the small end of the first friction-reducing inclined plane closest to the small end of the punch. S1This refers to the height of the small end of the first friction-reducing inclined surface near the small end of the punch. Maintaining a 50mm complete working inclined surface near the small end of the punch ensures sufficient contact area between the punch and the annular blank during the initial bending stage, allowing the annular blank to be stably clamped and positioned, preventing skewing or unstable deformation in the early stages of bending.

[0046] In some embodiments, the friction-reducing inclined surface is not provided within a 15mm drop range of the small end outer diameter of the punch, satisfying the following: ≥15, where d1 is the small end diameter of the punch, D S1 This refers to the diameter of the small end of the first anti-friction ramp closest to the small end of the punch. This feature, combined with the absence of the anti-friction ramp within a 50mm range, ensures that no anti-friction ramp is present in the diameter variation area near the small end of the punch. This prevents excessive wear on the small end of the punch, which could lead to punch durability issues and ensures the strength of the mold in this area. It also prevents the blank from entering the anti-friction ring groove and causing mold jamming during the initial stage of forming, thus preventing mold damage due to stress concentration during the forming process.

[0047] In some embodiments, the generatrix length of each working inclined plane is ≥60mm, i.e., it satisfies: ≥60, where D Sm Let D be the diameter of the lower end of the m-th friction-reducing inclined plane. M(m-1) H is the diameter of the upper end of the (m-1)th friction-reducing inclined plane. Sm H is the height of the lower end of the m-th friction-reducing inclined plane. M(m-1) This is the height of the upper end of the (m-1)th friction-reducing inclined plane. This feature ensures that each working inclined plane has sufficient length to allow the annular billet metal to deform sufficiently on the working inclined plane, while also ensuring that the punch has sufficient structural strength.

[0048] In some embodiments, the molding die further includes a lower anvil and an upper anvil.

[0049] In some embodiments, the outer diameter of the small end of the tapered ring forging is 150-2000 mm, the outer diameter of the large end is 300-3000 mm, the thickness is 30-200 mm, θ is 10-50°, and the height is 100-1500 mm.

[0050] When using the punch of this invention for bending, the friction is reduced due to the reduced contact area between the annular blank and the punch. According to Coulomb's law of friction, friction is proportional to the normal force, but not directly linearly related to the size of the contact area. However, in metal plastic forming, changes in the contact area affect the pressure distribution and the actual effect of friction on the contact surface. A reduced contact area makes the pressure distribution per unit area more concentrated, but the total frictional resistance decreases, and the radial flow resistance of the metal decreases accordingly, making radial deformation easier. At the same time, reducing the contact area also helps to delay the decrease in temperature of the annular blank's contact surface. During the bending process, heat transfer between the punch and the annular blank is the main reason for the decrease in the annular blank's temperature. A reduced contact area means fewer heat transfer channels, a slower rate of heat dissipation at the contact point of the annular blank, and the ability of the annular blank to deform at a higher temperature. Lower rigidity is beneficial for radial deformation, thereby reducing the bending draw.

[0051] During the bending process, the annular billet metal undergoes plastic flow under the action of the punch. With conventional punches, due to their large contact area and high frictional resistance, the resistance to metal flow in the diameter direction is greater than the resistance to flow in the height direction, causing the metal to preferentially flow in the height direction, resulting in a shortening of the forging's height. The friction-reducing punch of this invention reduces the contact area through a friction-reducing inclined surface, lowering the frictional resistance and thus reducing the resistance to metal flow in the diameter direction. Simultaneously, the angle between the inclined surface and the vertical direction is greater than 0°. During the punch's downward pressing process, the inclined surface generates a radial component force on the annular billet, guiding the metal to flow in the diameter direction. Under the combined effect of these two factors, the metal preferentially flows in the diameter direction rather than the height direction, thereby reducing the shortening in the height direction. By reducing the contact area, the friction-reducing punch of this invention slows down the temperature decrease rate of the annular billet's contact surface, allowing the annular billet to maintain good plasticity throughout the bending process. At the same time, due to reduced friction, the deformation heat effect is also weakened, resulting in a more uniform temperature distribution in the annular billet and avoiding uneven deformation caused by excessively low local temperatures. This optimization of thermo-mechanical coupling makes the bending process more stable and the dimensional accuracy of the forgings higher.

[0052] In a second aspect, the present invention provides a method for forming a tapered ring forging, wherein a forming die for bending and shortening the tapered ring forging is used in the forming process, comprising the following steps: The annular billet is placed on the lower anvil, and the punch is inserted into the annular billet; The upper anvil moves downward, contacts the punch, and drives the punch downward to shape the annular blank.

[0053] In some embodiments, the forming method includes the following steps: Step S1: Heat the sawn bar to the forging temperature and hold it at that temperature. The holding time is based on the effective thickness of the bar, with a holding time of 6 minutes for every 10 mm of effective thickness. After holding, the bar is upset and punched to obtain a ring billet. Step S2: After heating the ring billet, it is placed on the lever and then on the frame. Under the drive of the press, pressure is applied to the ring billet to reduce the wall thickness and expand the inner and outer diameters, thus obtaining the ring billet. Step S3: After heating the annular billet, place it on the lower anvil, then insert the punch into one end of the annular billet. Under the drive of the press, the upper anvil applies pressure to the punch, causing the punch to be pressed into the annular billet to obtain an irregular annular billet. Step S4: Heat the irregular ring billet, place the mandrel die into the irregular ring billet, and under the drive of the ring rolling mill, the mandrel die applies pressure to the irregular ring billet. The mandrel die and the main roll die roll the irregular ring billet to obtain a ring forging.

[0054] In a third aspect, the present invention provides a conical ring forging, which is manufactured using the forming method of the conical ring forging described above.

[0055] Example 1 Taking a conical ring forging made of TC4 material as an example, the rectangular blank dimensions of the forging are: Φ1740×Φ1400×1025. When using a traditional punch (punch small end outer diameter D1=1336mm, generatrix length 1078mm, generatrix angle with the vertical direction is 17°) for bending, the measured height reduction ΔH is approximately 215mm.

[0056] The friction-reducing punch of this embodiment of the invention is configured with four friction-reducing inclined surfaces for bending. The specific bending steps are as follows.

[0057] Step S1: Heat the annular billet to 950°C before shaping, and then place it stably on the lower anvil. The upper surface of the lower anvil should be kept horizontal to ensure that the annular billet is placed stably and to avoid tilting during the subsequent shaping process. Insert the friction-reducing punch into the inside of the annular billet with the small end of the punch facing down and the large end facing up. Align the central axis of the punch with the central axis of the annular billet to ensure that the force is symmetrical and uniform during the shaping process.

[0058] Step S2: The upper anvil moves downward, contacting the large end of the friction-reducing punch, causing the punch to move downward (e.g., Figure 6 As shown, during the downward pressing process of the punch, the outer surface of the punch generates a radial expansion force on the annular billet, causing the annular billet to deform in the diameter direction. At the same time, the annular billet undergoes a certain amount of compressive deformation in the height direction. Due to the friction-reducing inclined surface on the punch, the contact area between the punch and the annular billet is reduced, the frictional resistance is reduced, the metal preferentially flows in the diameter direction, and the amount of shrinkage in the height direction is significantly reduced.

[0059] After adopting the punch of this invention, the measured height reduction ΔH is approximately 102 mm. Compared with traditional technology, the technical solution of this invention reduces the height reduction by 53% and improves material utilization by 9.8%. For mass-produced tapered ring forgings, this improvement significantly reduces raw material consumption and production costs.

[0060] Example 2 Taking a conical ring forging made of 304 stainless steel as an example, the rectangular billet dimensions of the forging are: Φ1740×Φ1400×1025. When using a traditional punch (punch small end outer diameter D1=1336mm, generatrix length 1078mm, generatrix angle with the vertical direction is 17°) for bending, the measured height reduction ΔH is approximately 215mm.

[0061] The friction-reducing punch of this embodiment of the invention is configured with four friction-reducing inclined surfaces for bending. The specific bending steps are as follows.

[0062] Step S1: Heat the annular billet to 1150℃ before shaping, and then place it stably on the lower anvil. The upper surface of the lower anvil should be kept horizontal to ensure that the annular billet is placed stably and to avoid tilting during the subsequent shaping process. Place the friction-reducing punch inside the annular billet with the small end of the punch facing down and the large end facing up. Align the central axis of the punch with the central axis of the annular billet to ensure that the force is symmetrical and uniform during the shaping process.

[0063] Step S2: The upper anvil moves downwards, contacting the large end of the friction-reducing punch, causing the punch to move downwards. During the downward pressing process, the outer surface of the punch generates a radial expansion force on the annular billet, causing the annular billet to deform in the diameter direction. At the same time, the annular billet undergoes a certain amount of compression deformation in the height direction. Because the friction-reducing inclined surface is provided on the punch, the contact area between the punch and the annular billet is reduced, the frictional resistance is reduced, the metal preferentially flows in the diameter direction, and the amount of shrinkage in the height direction is significantly reduced.

[0064] Example 3 This embodiment uses the same method as Embodiment 1, except that the forming mold also includes a die, which is placed on the lower anvil and has an inner surface that matches the outer wall surface of the ring forging.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A forming die for forming a tapered ring forging, the forming die comprising a punch, characterized in that, The outer surface of the punch is provided with a plurality of annular working inclined surfaces; the working inclined surfaces are distributed axially at intervals on the outer surface of the punch, and a friction-reducing inclined surface is formed between adjacent working inclined surfaces; the friction-reducing inclined surface is recessed inward from the outer surface of the punch, and the recess depth is consistent along the radial direction.

2. A forming die for shaping a conical ring forging according to claim 1, characterized in that, The conical ring forging is a rotating forging with an upper diameter larger than a lower diameter. The small end of the punch is the lower end, and the large end is the upper end, with the upper diameter being larger than the lower diameter.

3. A forming die for shaping a conical ring forging according to claim 1, characterized in that, The difference between the upper and lower diameters of the different anti-friction inclined planes is the same, satisfying D. Mm -D Sm =D M(m+1) -D S(m+1) D Sm Let D be the diameter of the lower end of the m-th friction-reducing inclined plane. Mm Let D be the diameter of the upper end of the m-th friction-reducing inclined plane. S(m+1) Let D be the diameter of the lower end of the (m+1)th friction-reducing inclined plane. M(m+1) It is the diameter of the upper end of the (m+1)th friction-reducing inclined plane.

4. A forming die for shaping a conical ring forging according to claim 3, characterized in that, The difference between the diameter of the lowest point of the inwardly concave anti-friction inclined plane and the diameter of either the upper or lower end is the same, satisfying D. Lm -D Sm =D L(m+1) -D S(m+1) And D Mm -D Lm =D M(m+1) -D L(m+1) D Lm Let D be the diameter of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. L(m+1) It is the diameter of the lowest point of the inward concavity of the (m+1)th friction-reducing inclined plane.

5. A forming die for shaping a conical ring forging according to claim 1, characterized in that, The difference between the height of the upper end and the height of the lower end of the different anti-friction inclined planes is the same, satisfying H. Mm -H Sm =H M(m+1) -H S(m+1) H Sm H is the height of the lower end of the m-th friction-reducing inclined plane. Mm H is the height of the upper end of the m-th friction-reducing inclined plane. S(m+1) H is the height of the lower end of the (m+1)th friction-reducing inclined plane. M(m+1) It is the height of the upper end of the (m+1)th friction-reducing inclined plane.

6. A forming die for shaping a conical ring forging according to claim 5, characterized in that, The difference between the height of the lowest point of the inwardly concave anti-friction slope and the diameter of the upper end or the height of the lower end is the same, satisfying H. Lm -H Sm =H L(m+1) -H S(m+1) And H Mm -H Lm =H M(m+1) -H L(m+1) H Lm H is the height of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. L(m+1) It is the height of the lowest point of the (m+1)th friction-reducing inclined plane that is concave inward.

7. A forming die for shaping a conical ring forging according to claim 1, characterized in that, The angle between the generatrix of the friction-reducing inclined plane and the axial direction is greater than 0°, satisfying: D Lm >D Sm D Lm Let D be the diameter of the lowest point of the inward concavity of the m-th friction-reducing inclined plane. Sm Let be the diameter of the lower end of the m-th friction-reducing inclined plane; And / or the friction-reducing inclined surface is not provided on the side of the punch near the small end, within a 50mm range of the generatrix length, to satisfy the following conditions: ≥50, where d1 is the small end diameter of the punch, D S1 H is the diameter of the small end of the first friction-reducing inclined plane closest to the small end of the punch. S1 The height of the small end of the first friction-reducing inclined plane closest to the small end of the punch; And / or the friction-reducing inclined surface is not provided within a 15mm drop range of the small end outer diameter of the punch, satisfying: ≥15, where d1 is the small end diameter of the punch, D S1 The diameter of the small end of the first friction-reducing inclined plane closest to the small end of the punch; And / or the generatrix length of each of the said working inclined planes is ≥60mm, satisfying: ≥60, where D Sm Let D be the diameter of the lower end of the m-th friction-reducing inclined plane. M(m-1) H is the diameter of the upper end of the (m-1)th friction-reducing inclined plane. Sm H is the height of the lower end of the m-th friction-reducing inclined plane. M(m-1) It is the height of the upper end of the (m-1)th friction-reducing inclined plane.

8. A forming die for shaping a conical ring forging according to any one of claims 1-7, characterized in that, The molding die also includes a lower anvil and an upper anvil.

9. A method for forming a conical ring forging, characterized in that, The forming process employs a forming die for bending tapered ring forgings as described in any one of claims 1-8, comprising the following steps: The annular billet is placed on the lower anvil, and the punch is inserted into the annular billet; The upper anvil moves downward, contacts the punch, and drives the punch downward to shape the annular blank.

10. A conical ring forging, characterized in that, The conical ring forging is manufactured using the forming method for a conical ring forging as described in claim 9.

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