Sequential local loading die forging forming method and die based on open cavity design
By setting up a sequential local loading die forging and forming method of local open cavity structures on the mold, the problems of low forming accuracy and huge forming load in the prior art are solved, and the precise filling of the edge complex structure and stable deformation of the thin abdominal area are achieved, thereby reducing the forming load.
Patent Information
- Application Number
- CN202510279071.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-10
- Publication Date
- 2025-05-27
AI Technical Summary
When manufacturing components with local complex structures and thin-bow structures in the prior art, the forming accuracy is low, the forming load is huge, and the local loading forming method has problems such as many forming passages, long flows and weak deformation and strengthening effects caused by discontinuous alternate loading.
The sequential local loading die forging and molding method and mold are adopted based on the open cavity design. By setting up a partial open cavity structure on the mold, the preform blank is partially loaded and formed in the order from the edge to the center, thereby achieving accurate filling of the complex edge structure and stable deformation of the thin abdominal area.
It realizes precise filling of the edge complex structure and stable deformation of the thin abdominal area, reduces the forming load and avoids the occurrence of forming defects. It is suitable for various forgings with edge complex structures.
Smart Images
Figure CN120038260A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of material processing, and particularly to a sequential local loading die forging forming method and die based on an open cavity design. Background Art
[0002] Lightweighting is crucial in the aerospace field, having a significant impact on improving equipment mobility, load capacity, and reducing energy consumption. Components with complex local edge structures (such as ribs) and a thin web structure in the center, due to their combined in-plane direction, normal bearing capacity, and anti-bending, anti-torsion, and anti-shear characteristics, are extremely beneficial for greatly improving the static load stiffness and helping to achieve the ultimate lightweighting effect. Therefore, they are increasingly favored in the lightweight design and manufacturing of new aerospace equipment components such as space station hatch doors and cabin suspension brackets.
[0003] Currently, the mainstream manufacturing methods for such components at home and abroad include integral forging forming and local loading forming. However, the above manufacturing methods have the following problems: (1) Although integral forging forming has the advantages of high performance and high efficiency, when forming components with complex local edge structures, it faces problems such as low forming accuracy and extremely large forming loads. Specifically, since the complex edge structure is far from the loading center, the metal flows long-distance from the center to the edge. When forming the complex rib structure at the edge, the thin web area has completely conformed to the die. Therefore, additional overall deformation of the thin web area is required, and the forming load is largely consumed by the thin web area and is difficult to concentrate on the rib position, resulting in difficult filling of the complex rib structure. Moreover, due to the small thickness and large area of the thin web area, a triaxial compressive stress state is formed under the normal load, further increasing the forming force required for thinning deformation; (2) Although local loading forming can avoid the problems of the above integral forging forming, the existing local loading forming method is based on split dies (such as split punches and local pads) to alternately load different regions. This discontinuous alternate loading method results in multiple forming passes, a long process, and the billet needs to be reheated repeatedly or maintained at a continuous high temperature state, easily resulting in problems such as coarse grains and weak strain hardening effects.
[0004] Therefore, there is an urgent need to provide a new forming method applicable to components with complex local edge structures and a thin web structure in the center. Summary of the Invention
[0005] The purpose of this application is to provide a sequential local loading die forging forming method and die based on an open cavity design, which can achieve localized and controllable local loading during the overall die forging process, realize the integrated forming and property manufacturing of components with complex local edge structures, and solve the problems existing in the existing forming technologies.
[0006] The embodiments of this application can be realized through the following technical solutions:
[0007] A sequential local loading die forging forming method based on an open cavity design, including designing and processing a die and a preform according to a target forging, forging forming, and post-forming treatment steps. The shape of the target forging has a local complex structure at the edge and a thin web structure at the center. A local open cavity structure is provided in the area of the die corresponding to the thin web structure at the center of the target forging, so that when forging forming is carried out, the preform is locally loaded and formed in sequence from the edge to the center.
[0008] Further, the local open cavity structure refers to the cavity formed between the surface of the target forging and the working surface of the die close to it. The local loading forming specifically refers to the part of the blank being simultaneously attached to the upper and lower working surfaces of the die to form a forging deformation zone.
[0009] Further, the local open cavity structure is located on any one or more sides of the upper and lower die working surfaces of the die.
[0010] Further, the surface curvature of at least one of the upper and lower die working surfaces of the die is inconsistent with the surface curvature of the target forging surface worked by this working surface, and this working surface is located outside the surface of the target forging, so as to form a cavity between the two surfaces.
[0011] Further, a flow blocking structure is also provided on the die, which is located on the working surface corresponding to the transition zone between the local complex structure forging area and the central open cavity forging area.
[0012] Further, the diameter of the preform is set so that when forging forming is carried out, the edge of the preform is preferentially locally loaded and formed. The volume of the preform is set so that when forging forming is carried out, the preform can at least fill the local open cavity structure and meet the metal amount required for the overall deformation of the forging.
[0013] Further, the design and processing of the die and the preform specifically include initially designing the die configuration and the structural dimensions of the preform according to the shape of the target forging, optimizing the design of the die configuration and the structural dimensions of the preform through simulation analysis, and processing the die and the preform according to the optimized results. The forging forming specifically includes preheating the die to a specified temperature and spraying a lubricant, heating the blank to a specified temperature and holding it, and then putting it into the die for forging forming. The post-forming treatment specifically includes removing the flash and polishing to remove surface impurities after the forging is cooled.
[0014] Further, the die configuration includes the layout of the local open cavity structure of the die, the working surface dimensions, and the layout of the flow blocking structure. The layout of the local open cavity structure includes the open side orientation and the open area. The working surface dimensions include the surface curvature and the reserved machining allowance. The layout of the flow blocking structure includes the shape and position of the flow blocking structure.
[0015] A mold for the above die forging forming method, the mold includes an upper die and a lower die which are oppositely arranged. Among them, on the working surface of the upper die, there are edge complex structures distributed circumferentially along its edge. The profile curvature of at least one of the working surfaces of the upper die and the lower die is inconsistent with the profile curvature of the surface of the target forging it approaches, and this working surface is located outside the surface of the target forging, so as to form a locally open cavity between the two surfaces.
[0016] Furthermore, the mold further includes a receiving groove provided on the mold, which is located on the working surface of the mold corresponding to the central thin web area; a flash groove is also provided on the mold, which is located radially outside the edge complex structure and is distributed circumferentially on the working surface of the mold.
[0017] The sequential local loading die forging forming method and mold based on the open cavity design provided by the embodiments of the present application at least have the following
[0018] Beneficial effects:
[0019] Through the open cavity design, and by further optimizing the precise design of configuration elements such as the structural dimensions of the preform and the mold layout, etc., the present invention realizes sequential local loading from the edge of the blank to the center. The edge metal first fits with the upper and lower dies to form a forging deformation zone, and utilizes the short-range flow of metal to preferentially and precisely fill the complex rib structure; the thin web area is unidirectionally stretched by the upper die and fits with the mold sequentially from the edge to the center, and the stress state changes from triaxial compression to tension, effectively avoiding the triaxial compressive stress generated by the premature fitting of the central thin web area, preventing the sudden increase in the forming load instantaneously, and at the same time avoiding the long-range flow of metal and reducing the risk of the rise of work hardening and deformation resistance.
[0020] Furthermore, by optimizing the flow blocking structure of the mold, precisely controlling the metal flow resistance, and reasonably distributing the metal diversion ratio in the transition zone, the thin web area is stably deformed, and the occurrence of forming defects is avoided.
[0021] The present invention is applicable to various forgings with edge complex structures. By only slightly increasing the machining allowance of the blank, the forming load can be greatly reduced, and it has both economy and high efficiency. Description of the Drawings
[0022] Figure 1 It is a forging of sequential local loading based on an open cavity according to an embodiment of the present invention;
[0023] Figure 2 It is a technical principle diagram of the sequential local loading of the open cavity die forging forming of the present invention. In the figure, ① is the local complex structure forging area, and ② is the central open cavity forging area;
[0024] Figure 3 It is a comparison diagram of the sequential local loading of the open cavity of the present invention and the traditional integral forging method;
[0025] Figures 4 to 7 Schematic cross-sectional structure diagrams of molds according to different embodiments of the present invention;
[0026] Figure 8 Schematic diagram of defects in open cavity sequential local loading die forging forming;
[0027] Reference numerals in the figure: 1 - mold, 11 - upper die, 111 - complex edge structure, 112 - working surface of the upper die, 12 - lower die, 121 - working surface of the lower die, 13 - partially open cavity, 14 - receiving groove, 15 - flash groove, 16 - flow resistance structure, 2 - preform, 32 - upper surface of the target forging, 33 - lower surface of the target forging; Specific embodiments
[0028] Hereinafter, the present application will be further described based on preferred embodiments with reference to the accompanying drawings.
[0029] The present invention provides a forming method applicable to components with local complex structures (such as rib structures) at the edge and thin web structures at the center as shown in Figure 1 . The following will specifically elaborate on the die forging forming method of the present invention in combination with Figure 2 and Figure 3 . As described in the background art, when using traditional integral die forging forming, the thin web area at the center bears the load first during forging, that is, the blank in this area first adheres to the die to become the forging deformation area, and then the deformation area gradually expands towards the edge. Due to the small thickness and large area of the thin web area, it presents a triaxial compressive stress state under the action of the normal load, which makes the forming load required for further thinning deformation extremely large. At the same time, the local complex features are far from the loading center, and the metal needs to flow a long distance through the difficult-to-deform area to complete filling. Since the thin web area at the center has already completely adhered to the die when forming the local complex features at the edge, this requires the entire large-area difficult-to-deform area to deform, which greatly reduces the formability of the local complex structure at the edge. To solve the above problems, the present invention provides a sequential local loading die forging forming method based on an open cavity. By setting a partially open cavity structure in the area of the mold corresponding to the thin web structure at the center of the target forging, the preform is sequentially locally loaded and formed in the order from the edge to the center during forging, that is, the blank in the area of the local complex structure at the edge first adheres to the upper and lower working surfaces of the die to form a forging deformation area, and then the forging deformation area expands sequentially towards the center; this method can achieve precise filling of the local complex structure at the edge before the thin web area completely adheres to the die. The present invention changes the long-range flow of metal in the traditional local complex structure area into short-range flow filling of metal, and also makes the difficult-to-deform area in traditional integral die forging forming change from being under triaxial compressive stress to being under biaxial tensile stress of the die, greatly reducing the forming load.
[0030] The sequential local loading die forging forming method based on the open cavity design of the present invention specifically includes the following steps:
[0031] S1. Design and process the die and preform according to the target forging;
[0032] Specifically, this step includes initially designing the die configuration and the structural dimensions of the preform according to the shape of the target forging; and optimizing the design of the die configuration and the structural dimensions of the preform through simulation analysis, so that the edge position is the first to contact the die to form a forging deformation zone during forging, and then the forging deformation zone sequentially expands towards the center direction; processing the die and the preform according to the optimized results;
[0033] Furthermore, the die configuration specifically includes the structural layout of the local open cavity of the die and the working surface dimensions;
[0034] Specifically, the local open cavity refers to the cavity formed between the surface of the target forging and the die working surface close to it; the local open cavity is located in the area of the die corresponding to the center thin web structure of the target forging;
[0035] Furthermore, the structural layout of the local open cavity of the die includes the orientation of the open side and the open area; in some specific embodiments, as Figure 4 shown, the local open cavity 13 is located on the side of the lower die working surface 121 of the die, that is, the surface curvature of the upper die working surface 112 of the die is consistent with the surface curvature of the upper surface 32 of the target forging close to it, while the surface curvature of the lower die working surface 121 of the die is inconsistent with the surface curvature of the lower surface 33 of the target forging close to it, and the lower die working surface 121 is located outside the lower surface 33 of the target forging, and the cavity formed between the lower die working surface 121 and the lower surface 33 of the target forging constitutes the local open cavity 13; in some other specific embodiments, as Figure 5 and Figure 6 shown, the local open cavity 13 can also be located on the side of the upper die working surface 112 of the die, or local open cavities 13 are provided on both the side of the upper die working surface 112 and the side of the lower die working surface 121 of the die.
[0036] Furthermore, in some specific embodiments, the local open cavity 13 is a closed structure; in some other alternative embodiments, as Figure 7 shown, the local open cavity 13 can also be an open structure.
[0037] Furthermore, in some preferred embodiments, the die configuration also includes the choke structure layout. Since the diversion metal will be generated after the forging deformation zone is formed at the edge position, the center thin web area will be affected by the compressive stress of the diversion metal and will appear as Figure 8The shown forming defects are as follows: on the one hand, the thin web area is affected by the inflow of shunted metal, resulting in the relaxation of internal tensile stress and even the buckling deformation under axial compression, and there will be a phenomenon of excessive bulging in the middle of the blank, leading to folding; on the other hand, when the blank in the thin web area is discontinuous at the contact position with the mold on the open cavity side, local bending / shearing instability of the metal will occur near the transition area; therefore, in some preferred embodiments, by further arranging a flow blocking structure on the mold, and through the layout of the flow blocking structure and the optimization of other elements of the mold configuration, it can not only achieve the priority filling of the complex edge features and the sequential expansion of the forging deformation area towards the center direction, but also avoid the appearance of the above-mentioned forming defects in the central thin web area.
[0038] Specifically, the layout of the flow blocking structure includes the shape and position of the flow blocking structure; in some preferred embodiments, the flow blocking structure 16 is located on the working surface of the mold corresponding to the transition area between the local complex structure forging area ① and the central open cavity forging area ②; in some specific embodiments, the shape of the flow blocking structure 16 can be a flow blocking groove, a flow blocking rib or other commonly used structures in the art.
[0039] Furthermore, the size of the working surface includes the surface curvature and the reserved machining allowance;
[0040] Furthermore, the structural dimensions of the preform specifically include the shape, size, etc. of the preform; in some specific embodiments, the preform is disc-shaped, and the diameter of the preform is similar to the diameter of the target forging, that is, the diameter of the preform is set as long as it satisfies that when forging and forming, the edge of the preform is preferentially locally loaded and formed; furthermore, the volume of the preform is set to satisfy that when forging and forming, the preform can at least fill the local open cavity structure and can meet the metal amount required for the overall deformation of the forging.
[0041] Furthermore, the simulation analysis for optimizing the design of the mold configuration and the structural dimensions of the preform includes analyzing the influence of the mold configuration and the structural dimensions of the preform on the expansion path of the forging deformation area during the forming process, the influence of the flow blocking structure on the metal flow resistance, etc.;
[0042] S2. Forging and forming: preheat the mold to the specified temperature and spray lubricant, heat the preform to the specified temperature and keep it warm, and then put it into the mold for forging and forming;
[0043] S3. Post-forming treatment: cool the forging and then remove the flash and polish to remove impurities such as surface oxide scale.
[0044] It should be noted that the forming method of the present invention is applicable to metal forgings with complex structures at the edge and thin web structures at the center. The central thin web area can be a curved surface, a flat surface, or can also include such as Figure 1The simple geometric configuration shown only needs to satisfy the condition of having a thin web structure; the metal can be various non-ferrous metals such as titanium alloys, aluminum alloys, magnesium alloys, copper alloys, etc. and ferrous metals such as steel.
[0045] The present invention also provides a mold for the above-mentioned sequential local loading die forging forming of an open cavity. The mold 1 includes an upper mold 11 and a lower mold 12 which are oppositely arranged. Among them, on the working surface 112 of the upper mold, there is a complex edge structure 111 distributed circumferentially along its edge. The surface curvature of at least one of the working surface 112 of the upper mold and the working surface 121 of the lower mold is inconsistent with the surface curvature of the target forging it approaches, and this working surface is located outside the surface of the target forging, so as to form a local open cavity 13 between the two surfaces;
[0046] In some preferred embodiments, the mold 1 is also provided with a receiving groove 14, which is used to reserve sufficient flow space for the blank metal to avoid excessive forming load caused by complete filling; in some specific embodiments, the receiving groove 14 is arranged on the mold working surface corresponding to the central thin web area;
[0047] In some preferred embodiments, the mold 1 is also provided with a flash groove 15, which is located radially outside the complex edge structure 111 and is distributed circumferentially on the working surface of the mold.
[0048] Embodiment
[0049] This embodiment provides a forming method for a forging whose edge is a complex rib structure, has a curved thin web area in the center, and has a through hole structure in the center of the thin web area as shown in Figure 1 The specific steps are as follows:
[0050] (1) Initially design the mold configuration and the structural dimensions of the preform according to the shape of the target forging, and optimize the design of the mold configuration and the structural dimensions of the preform through simulation analysis;
[0051] After optimization design, the shape of the preform is a disk-shaped structure with uneven thickness. Its bottom surface is flat, the edge thickness is greater than the abdominal thickness, and a bevel transition is adopted between the two. Specifically, its diameter is 174 mm, the diameter of the central hole is 24 mm, the edge thickness is 14 mm, and the abdominal thickness is 7 mm;
[0052] The mold after optimization design is as shown in Figure 4As shown in the figure, it includes an upper die and a lower die which are oppositely arranged. Among them, a flash groove is provided along the circumference at the edge of the working surface of the upper die. A locally complex rib structure is provided on the radially inner side of the flash groove. The surface curvature of the working surface on the radially inner side of the locally complex rib structure is consistent with the surface curvature of the upper surface of the target forging. At the center of the upper die is a cylindrical groove that cooperates with the cylindrical protrusion at the center of the lower die. The depth of this groove cooperates with the cylindrical protrusion to ensure the smooth closing of the upper and lower dies; a flash groove is also provided at the edge of the working surface of the lower die. The working surface on the radially inner side of the flash groove is an inclined surface with a gradually changing curvature. A cavity is formed between this inclined surface with a gradually changing curvature and the lower surface of the target forging, and the normal distance between the two surfaces gradually increases from the edge to the center. The depth of this inclined surface (i.e., the vertical distance from the lowest point of this inclined surface to the highest point of the working surface of the lower die) is 22 mm. At the center of the lower die is a cylindrical protrusion with a diameter of 20 mm.
[0053] (2) Process the corresponding preform and die according to the above design;
[0054] (3) Use a heating rod to preheat the die for 4 - 5 hours. During the heating process, use an asbestos blanket for heat preservation to keep the die temperature at about 300 °C;
[0055] (4) Preheat the blank in a box furnace, hold it at 780 °C for 120 minutes and then perform forging. Spray Ti - 1 glass protective lubricant during forging;
[0056] (5) After forging, perform cooling. Cut off the flash and polish the surface of the cooled forging to remove surface impurities to obtain the target forging that meets the final requirements.
[0057] During the forming process of this embodiment, as the loading amount increases, the metal at the edge deforms first and fills the rib structure. The blank inside is stretched downward by the single - phase action of the upper die. However, due to the existence of the locally open cavity, the blank will not directly and completely fit the working surface of the lower die. Instead, it gradually fits the die from the edge to the center in sequence. Before the complete fitting of the die causes a sharp increase in the loading force, the forming of the complex rib structure at the edge has been completed. The forming load of this embodiment is reduced by nearly 50% compared with traditional integral forging.
[0058] The above has made a detailed introduction to the specific implementation manners of this application. For those skilled in the art of this technology, without departing from the principle of this application, several improvements and modifications can still be made to this application, and these improvements and modifications also belong to the protection scope of the claims of this application.
Claims
1. A sequential local loading die forging method based on an open cavity design, comprising the steps of designing and processing a die and a preform according to a target forging, forging and forming, and post-forming processing, characterized in that: The target forging has a shape with a locally complex structure at the edge and a thin belly structure at the center; The area on the die corresponding to the central thin belly structure of the target forging is provided with a partially open cavity structure, so that when forging is performed, the preform is locally loaded and formed in sequence from the edge to the center.
2. The die forging method according to claim 1, characterized in that: The partially open cavity structure refers to the cavity formed between the surface of the target forging and the working surface of the die close to it; The local loading forming specifically refers to that the portion of the blank is simultaneously fitted with the upper and lower working surfaces of the die to form a forging deformation zone.
3. The die forging method according to claim 2, characterized in that: The partially open cavity structure is located on any one side or multiple sides of the upper and lower mold working surfaces of the mold.
4. The die forging method according to claim 3, characterized in that: At least one of the upper and lower die working surfaces of the die has a different curvature from the target forging surface on which it works, and the working surface is located outside the target forging surface so that a cavity is formed between the two surfaces.
5. The die forging method according to claim 4, characterized in that: The mold is also provided with a flow-blocking structure, which is located on a working surface corresponding to a transition zone between a local complex structure forging zone and a central open cavity forging zone.
6. The die forging method according to claim 1, characterized in that: The diameter of the preform is set so that when forging is performed, the edge of the preform is preferentially locally loaded and formed; The volume of the preform is set so that when forging is performed, the preform can at least fill the partially open cavity structure and can meet the metal amount required for the overall deformation of the forging.
7. The die forging method according to claim 1, characterized in that: The design and processing of the mold and the preform specifically includes preliminarily designing the mold configuration and the structural dimensions of the preform according to the shape of the target forging, optimizing the mold configuration and the structural dimensions of the preform through simulation analysis, and processing the mold and the preform according to the optimized results; The forging process specifically includes preheating the die to a specified temperature and spraying a lubricant, heating the blank to a specified temperature and keeping the temperature, and then placing the blank into the die for forging; The post-forming treatment specifically includes cutting off the flash and polishing to remove surface impurities after the forging is cooled.
8. The die forging method according to claim 7, characterized in that: The mold configuration includes the mold's partial open cavity structure layout, working surface size and flow-blocking structure layout, the partial open cavity structure layout includes the open side orientation and the open area, the working surface size includes the mold surface curvature and the reserved processing allowance, and the flow-blocking structure layout includes the shape and position of the flow-blocking structure.
9. A die for the die forging method according to claim 1 to claim 8, characterized in that: The mold comprises an upper mold and a lower mold which are arranged opposite to each other, wherein a complex edge structure is provided on the working surface of the upper mold and distributed circumferentially along its edge, and a profile curvature of at least one of the upper mold working surface and the lower mold working surface is inconsistent with a profile curvature of a surface of a target forging it is close to, and the working surface is located outside the surface of the target forging so that a partially open cavity is formed between the two surfaces.
10. The mold according to claim 9, characterized in that: The mold is also provided with a receiving groove, which is located on the mold working surface corresponding to the central thin belly area; the mold is also provided with a flash groove, which is located radially outside the complex edge structure and distributed circumferentially on the mold working surface.