Large-height-diameter-ratio metal blank upsetting preparation die and preparation method
By designing pre-upsetting and upsetting components, and utilizing billet limiting and gradually expanding cavity wall profiles, the problem of instability and folding of metal billets with large aspect ratios during upsetting deformation was solved, achieving high-efficiency forming quality and precision.
Patent Information
- Application Number
- CN202510938511.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-08
- Publication Date
- 2025-10-03
AI Technical Summary
In traditional upsetting deformation processes, metal billets with large aspect ratios are prone to instability, leading to defects such as surface folding and incomplete filling, which affect the safety of product use.
By employing pre-upsetting components and upsetting forming components, and through the design of blank limiting holes, pre-upsetting mold cavities, and upsetting forming concave cavities, the lateral displacement of metal blanks with large height-to-diameter ratios is limited. Combined with parabolic and smoothly expanding cavity wall profiles, the metal blanks are promoted to gradually fill the cavity space, and the large end is placed downwards during the second upsetting to avoid instability and folding.
This effectively avoids instability and folding of metal billets with large aspect ratios during the upsetting process, ensuring forming quality and improving forming accuracy and efficiency.
Smart Images
Figure CN120734243A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of metal plastic processing and forming, and particularly relates to a die for preparing a metal blank by upsetting it with a large aspect ratio and a preparation method thereof. Background Art
[0002] In the field of metal plastic processing, upsetting deformation is the initial step in the forming process. However, in traditional techniques, the aspect ratio of upsetting deformation cannot exceed 2.5. Metal billets with large aspect ratios (i.e., aspect ratios exceeding 2.5) often exhibit instability during traditional upsetting deformation, easily causing distortion and subsequent defects such as folding and incomplete filling on the material surface. This means that subsequent deformation will cause defects, affecting product safety. How to further optimize the upsetting forming process and address the instability, folding, and filling defects of metal billets with large aspect ratios during upsetting deformation remains an urgent issue in the industry. Summary of the Invention
[0003] Therefore, the present invention provides a die and a method for preparing a metal billet with a large aspect ratio by upsetting, which can overcome the technical problems of unstable folding and filling defects of metal billets with a large aspect ratio during upsetting deformation in the related art.
[0004] In order to solve the above problems, the present invention provides a pre-upsetting preparation die for metal billets with a large aspect ratio, including a pre-upsetting component, the pre-upsetting component including a first punch and a prefabricated lower die, the prefabricated lower die consisting of an upper die body and a lower die body that are buckled together, the upper die body having a billet limiting hole passing through its upper and lower ends, the first punch being able to pass through the billet limiting hole from top to bottom, a pre-upsetting die cavity in the form of a rotating body being formed on the lower die body, the pre-upsetting die cavity including a billet bottom end limiting barrel section and a billet upsetting barrel section in sequence from bottom to top, the billet bottom end limiting barrel section and the billet upsetting barrel section being smoothly connected, and the caliber of the billet upsetting barrel section smoothly expands from bottom to top.
[0005] In some embodiments, in the longitudinal section of the blank upset barrel section, the barrel inner wall profile of the blank upset barrel section is a parabola.
[0006] In some embodiments, the pre-upsetting die cavity further includes a cylindrical section located at one end of the billet upsetting cylinder section away from the billet bottom end limiting cylinder section, the cylindrical section is smoothly connected to the billet upsetting cylinder section, and the inner diameter of the cylindrical section is smaller than the final upsetting target diameter of the large aspect ratio metal billet 100.
[0007] In some embodiments, the large aspect ratio metal blank upsetting preparation die also includes an upsetting forming assembly, the upsetting forming assembly includes a forming die and a second punch, the forming die has an upsetting forming cavity, the caliber of the upsetting forming cavity is equal to the outer diameter of the second punch, and both are not less than the inner diameter of the cylindrical section.
[0008] In some embodiments, a first ejector pin is provided on the bottom wall of the pre-upsetting die cavity, and a second ejector pin is provided on the bottom wall of the upsetting forming cavity.
[0009] In some embodiments, the overall height of the pre-upsetting die cavity is H, the overall height of the blank limiting hole is h, the initial length of the large aspect ratio metal blank is L, H+h≥L, and when the large aspect ratio metal blank is placed in the pre-upsetting assembly and is not upset, the volume of the portion of the large aspect ratio metal blank in the blank limiting hole is not greater than the volume of the cavity portion of the pre-upsetting die cavity.
[0010] In some embodiments, the diameter of the metal blank with a large aspect ratio is D, the aperture of the blank limiting hole is d1, the diameter of the limiting barrel section at the bottom end of the blank is d2, and d1=d2=D+1 mm.
[0011] In some embodiments, the engaging surfaces of the upper mold body and the lower mold body have concave and convex positioning structures.
[0012] According to an embodiment of the present invention, there is also provided a method for upsetting a metal billet with a large aspect ratio using the above-mentioned metal billet upsetting die, comprising the following steps:
[0013] The high aspect ratio metal blank, the pre-upsetting component and the upsetting forming component are heated to the target forming temperature and kept warm;
[0014] Assembling the pre-upsetting assembly on a press, placing the metal blank with a large aspect ratio into the pre-upsetting assembly through the blank limiting hole, and limiting the bottom end of the metal blank with a large aspect ratio in the blank bottom limiting cylinder section;
[0015] Controlling the operation of the press to drive the first punch downward to apply force to the top end of the metal blank with a large aspect ratio so that the metal blank with a large aspect ratio fills the pre-upsetting die cavity from bottom to top along the cavity wall profile of the pre-upsetting die cavity, thereby preparing an upsetting blank with a smaller lower end and a larger upper end;
[0016] After heating the upset blank to the target forming temperature again, the upset blank is placed into the upset forming assembly assembled on the press, with the large end and the small end of the upset blank positioned downward;
[0017] The press is controlled to drive the second punch downward to apply force to the small end of the upsetting blank until the upsetting blank fills the forming space formed between the second punch and the upsetting forming cavity from top to bottom, thereby preparing a formed part of the target size.
[0018] In some embodiments, before the upsetting blank is heated again, edge burrs on the upsetting blank are removed; and / or, before the high aspect ratio metal blank is placed in the pre-upsetting assembly, lubricant is applied to the hole wall of the blank limiting hole, the cavity wall of the pre-upsetting die cavity, and the working end of the first punch; and / or, before the upsetting blank is placed in the upsetting forming assembly, lubricant is applied to the cavity wall of the pre-upsetting die cavity and the working end of the second punch.
[0019] The present invention provides a large aspect ratio metal blank upsetting preparation die and preparation method has the following characteristics:
[0020] Beneficial effects:
[0021] The blank limiting hole and the blank bottom limiting barrel section respectively constrain the top shaft section and the bottom end of the metal blank with a large aspect ratio, inhibit the lateral deviation (i.e. radial deviation) of the metal blank with a large aspect ratio, and limit the upsetting deformation part of the metal blank with a large aspect ratio to the corresponding cavity of the blank upsetting barrel section with a smooth and gradually expanding diameter from bottom to top. The smooth and gradually expanding cavity wall profile conforms to the metal upsetting flow law, which can promote the metal blank with a large aspect ratio to gradually fill the cavity space from bottom to top along the cavity wall, effectively avoiding the instability and folding of the metal blank with a large aspect ratio during the initial upsetting process; at the same time, the formed upsetting blank has one end larger than the other end and the blank surface between the large end and the small end is a circular gradually expanding curved surface. When the upsetting blank is subjected to secondary upsetting, the large end can be placed downward, which can effectively avoid the instability and folding of the upsetting blank during the second upsetting process, further ensuring the forming quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. The drawings described below are merely exemplary. Those skilled in the art can, without inventive effort, derive other implementation drawings based on the provided drawings.
[0023] Figure 1 1 is a schematic structural diagram of a pre-upsetting assembly in a die for preparing a metal billet having a large aspect ratio according to an embodiment of the present invention, wherein the figure contains a metal billet having a large aspect ratio;
[0024] Figure 2 yes Figure 1 Schematic diagram of the state after the pre-upsetting component in the figure realizes the pre-upsetting of the metal billet with a large aspect ratio;
[0025] Figure 3 yes Figure 1 Schematic diagram of the longitudinal section of the lower mold body;
[0026] Figure 41 is a schematic structural diagram of an upsetting forming assembly in a die for upsetting a metal blank having a large aspect ratio in accordance with an embodiment of the present invention, wherein the upsetting blank is included;
[0027] Figure 5 yes Figure 4 A schematic diagram of the state of the upsetting forming component after the upsetting blank is upset twice;
[0028] Figure 6 1 is a schematic diagram of a process in which a metal blank with a large aspect ratio is prepared and finally upset into a formed part with a target size in an embodiment of the present invention.
[0029] The accompanying drawings are:
[0030] 1. First punch; 21. Upper die; 211. Blank limiting hole; 22. Lower die; 221. Pre-upsetting die cavity; 2211. Blank bottom limiting cylinder section; 2212. Blank upsetting cylinder section; 2213. Cylinder section; 23. First ejector pin; 3. Forming die; 31. Upsetting forming cavity; 32. Second ejector pin; 4. Second punch; 100. Metal blank with large aspect ratio; 200. Upsetting blank. DETAILED DESCRIPTION
[0031] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0032] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.
[0033] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90° or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.
[0034] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.
[0035] See also Figures 1 to 6 As shown, according to an embodiment of the present invention, a die for preparing a metal blank with a large aspect ratio by upsetting is provided, comprising a pre-upsetting assembly (not labeled in the figure), the pre-upsetting assembly comprising a first punch 1 and a prefabricated lower die (not labeled in the figure), the prefabricated lower die comprising an upper die body 21 and a lower die body 22 that are buckled together, the upper die body 21 having a blank limiting hole 211 passing through the upper and lower ends thereof, the first punch 1 being able to pass through the blank limiting hole 211 from top to bottom, the lower die body 22 being formed with a blank limiting hole 211 formed therein. The pre-upsetting die cavity 221 of the rotating body, and the lower end face of the aforementioned upper die body 21 can form a blockage for the opening of the pre-upsetting die cavity 221, and the pre-upsetting die cavity 221 includes, from bottom to top, a blank bottom end limiting barrel section 2211 (cylindrical) and a blank upsetting barrel section 2212, and the blank bottom end limiting barrel section 2211 and the blank upsetting barrel section 2212 are smoothly connected, and the caliber of the blank upsetting barrel section 2212 (that is, the cross-sectional diameter of the inner wall of the cavity) is smoothly expanded from bottom to top.
[0036] In this technical solution, the blank limiting hole 211 and the blank bottom limiting barrel section 2211 respectively constrain the top shaft section and the bottom end of the large aspect ratio metal blank 100, suppressing the lateral deviation (i.e. radial deviation) of the large aspect ratio metal blank 100, and limiting the upsetting deformation part of the large aspect ratio metal blank 100 to the corresponding cavity of the blank upsetting barrel section 2212 with a diameter that is smoothly expanded from bottom to top. The smooth and gradually expanded cavity wall profile conforms to the metal upsetting flow law, which can promote the large aspect ratio metal The blank 100 gradually fills the cavity space from bottom to top along the cavity wall, effectively avoiding the instability and folding of the metal blank 100 with a large aspect ratio during the initial upsetting process; at the same time, the formed upsetting blank 200 is formed with one end large and the other end small, and the blank surface between the large end and the small end is a circular gradually expanding curved surface. When the upsetting blank 200 is subjected to secondary upsetting, it can be placed with the large end facing downward, which can effectively avoid the instability and folding of the upsetting blank 200 during the second upsetting process, thereby further ensuring the forming quality.
[0037] In some embodiments, on the longitudinal section of the blank upset barrel section 2212, the inner wall profile of the blank upset barrel section 2212 is a parabola. In some specific embodiments, the inner wall profile, i.e., the generatrix, conforms to the parabola equation y=a·x 2 , where a is a constant greater than 0. This allows for a smooth, gradual expansion of the parabola while ensuring that the enclosed upsetting barrel section 2212 has a larger opening diameter variation at the same die height, providing greater blank accommodation capacity. This results in a greater deformation and higher deformation uniformity after a single upsetting deformation, which is beneficial for grain refinement, improved microstructure, and enhanced strength. In one specific embodiment, a = 0.014.
[0038] In some embodiments, the pre-upsetting die cavity 221 further includes a cylindrical section 2213 located at an end of the blank upsetting barrel section 2212 away from the blank bottom end limiting barrel section 2211. The cylindrical section 2213 is smoothly connected to the blank upsetting barrel section 2212, and the inner diameter of the cylindrical section 2213 is smaller than the final upsetting target diameter of the high aspect ratio metal blank 100. It is understood that the smooth connection mentioned above is specifically achieved by rounding with an appropriate radius. In a specific embodiment, the cylindrical section 2213 and the blank upsetting barrel section 2212 are connected via a rounded transition of R500mm, which can ensure the same smooth transition between the small end face and the large end face of the upsetting blank 200 in the second pass, further preventing the upsetting blank 200 from folding during the second upsetting deformation, thereby ensuring the forming quality.
[0039] In this technical solution, a cylindrical section 2213 is further provided at the top end of the blank upsetting cylindrical section 2212, and a vertical angle is formed between the cylindrical section 2213 (that is, the top end surface of the lower mold body 22) and the bottom end surface of the upper mold body 21, which can prevent the formation of a narrow cavity angle between the top end surface of the lower mold body 22 and the bottom end surface of the upper mold body 21, and prevent the formation of the aforementioned narrow cavity angle, which will cause the flow friction of the blank to be large, thereby causing the blank to be filled more fully in the pre-upsetting die cavity 221, thereby ensuring the forming dimensional accuracy after the subsequent second upsetting forming.
[0040] In some embodiments, the large aspect ratio metal blank upsetting preparation die also includes an upsetting forming assembly (not labeled in the figure), the upsetting forming assembly includes a forming die 3 and a second punch 4, the forming die 3 has an upsetting forming cavity 31, the caliber of the upsetting forming cavity 31 and the outer diameter of the second punch 4 are equal, and both are not less than the inner diameter of the cylindrical section 2213, so that the caliber of the aforementioned second punch 4 and the upsetting forming cavity 31 of the forming die 3 form a high-precision match.
[0041] In this technical solution, the upsetting forming assembly cooperates with the aforementioned pre-upsetting assembly to perform both pre-upsetting and secondary upsetting of the blank. This allows for simple and efficient upsetting of metal blanks with large aspect ratios, reducing the difficulty of upsetting. During preparation, the upset blank 200 is positioned with its large end facing downward and its small end facing upward, with the second punch 4 applying force to the small end. This increases the unit stress, thereby improving the efficiency of the secondary upsetting process. It also effectively prevents instability and folding of the upset blank 200 during the secondary upsetting process, further ensuring forming quality.
[0042] See Figure 1 and Figure 4 As shown, in some embodiments, a first push rod 23 is provided on the bottom wall of the pre-upsetting die cavity 221. By controlling the lifting of the first push rod 23, the formed upsetting blank 200 can be ejected from the pre-upsetting die cavity 221 after the upper die body 21 is removed from the top end surface of the lower die body 22. A second push rod 32 is provided on the bottom wall of the upsetting forming cavity 31. By controlling the second push rod 32, the final formed part can be ejected from the upsetting forming cavity 31 to facilitate discharge.
[0043] In some embodiments, the overall height of the pre-upsetting die cavity 221 is H, the overall height of the blank limiting hole 211 is h, the initial length of the large aspect ratio metal blank 100 is L, H+h≥L, and when the large aspect ratio metal blank 100 is placed in the pre-upsetting assembly and is not upset, the volume of the portion of the large aspect ratio metal blank 100 in the blank limiting hole 211 is not greater than the volume of the cavity portion of the pre-upsetting die cavity 221, and the volume of the aforementioned cavity portion is also as shown in FIG. Figure 1In the state shown, an annular cavity is formed between the radially outer side of the high aspect ratio metal blank 100 and the inner wall of the pre-upsetting die cavity 221 .
[0044] In this technical solution, the volume of the portion of the large aspect ratio metal blank 100 in the blank limiting hole 211 is designed to be no larger than the volume of the cavity portion of the pre-upsetting die cavity 221. This ensures that all metal materials enter the pre-upsetting die cavity 221 below after pre-upsetting the aforementioned large aspect ratio metal blank 100, preventing excess material from being on the large end surface of the upsetting blank 200 formed after pre-upsetting, thereby ensuring the flatness of the large end surface of the upsetting blank 200 and ensuring the position stability of the subsequent secondary upsetting and inverted upsetting blank 200.
[0045] In some embodiments, the diameter of the metal billet with a large aspect ratio is D, the aperture of the billet limiting hole 211 is d1, and the diameter of the billet bottom end limiting barrel section 2211 is d2, d1=d2=D+1mm, so as to ensure that the metal billet with a large aspect ratio can be smoothly placed in the pre-upsetting component while preventing the gap between the metal billet and the corresponding billet limiting hole 211 or the billet bottom end limiting barrel section 2211 from being too large, resulting in the billet posture becoming unstable during the upsetting process.
[0046] See further Figure 1 As shown, in some embodiments, the upper mold body 21 and the lower mold body 22 have concave and convex positioning structures on their engaging surfaces. Specifically, as shown in FIG. Figure 1 As shown, an annular boss (not labeled in the figure) is provided on the top end surface of the lower die body 22, and a circular groove (not labeled in the figure) is provided on the bottom end surface of the upper die body 21. The aforementioned annular boss and circular groove can ensure that the rotation axis of the aforementioned blank limiting hole 211 and the pre-upsetting die cavity 221 are coaxial. It can be understood that a corresponding connecting and fixing structure is also provided between the aforementioned upper die body 21 and the lower die body 22, such as a plurality of connecting bolts, or a clamp provided around the outer peripheral wall of the two die bodies, etc. The present invention does not make any special restrictions thereto. In principle, it is sufficient to ensure that the upper die body 21 and the lower die body 22 are reliably positioned and connected in the axial and radial directions.
[0047] According to an embodiment of the present invention, there is also provided a method for upsetting a metal billet with a large aspect ratio using the above-mentioned metal billet upsetting die, comprising the following steps:
[0048] The high aspect ratio metal blank 100, the pre-upsetting assembly, and the upsetting forming assembly are heated to a target forming temperature and kept warm. In a specific embodiment, the target forming temperature is 400° C.
[0049] Assemble the pre-upsetting assembly onto a press, place the high aspect ratio metal blank 100 into the pre-upsetting assembly through the blank limiting hole 211, and limit the bottom end of the high aspect ratio metal blank 100 within the blank bottom limiting barrel section 2211;
[0050] The press is controlled to drive the first punch 1 downward to apply force to the top of the large aspect ratio metal blank 100 so that the large aspect ratio metal blank 100 fills the pre-upsetting die cavity 221 from bottom to top along the cavity wall profile of the pre-upsetting die cavity 221, thereby preparing an upsetting blank 200 with a smaller lower end and a larger upper end. At this time, the upper die body 21 is removed from the top surface of the lower die body 22, and the first ejector pin 23 is controlled to eject the upsetting blank 200.
[0051] After the upset blank 200 is heated again to the target forming temperature, it is placed into the upset forming assembly assembled on the press, with the large end and the small end of the upset blank 200 positioned downward. The press may be the press assembled with the pre-upsetting assembly, or may be another independent press, which is not particularly limited in the present invention.
[0052] The press is controlled to drive the second punch 4 downward to apply force to the small end of the upsetting blank 200 until the upsetting blank 200 fills the forming space formed between the second punch 4 and the upsetting forming cavity 31 from top to bottom, thereby preparing a formed part of the target size.
[0053] In this technical solution, a pre-upsetting assembly is first used to perform the first upsetting of the large aspect ratio metal blank 100. During the upsetting process, the blank limiting hole 211 of the pre-upsetting assembly and the blank bottom limiting barrel section 2211 respectively constrain the top shaft section and the bottom end of the large aspect ratio metal blank 100, thereby suppressing the lateral offset (i.e. radial offset) of the large aspect ratio metal blank 100, and limiting the upsetting deformation part of the large aspect ratio metal blank 100 to the corresponding cavity of the blank upsetting barrel section 2212, the caliber of which is smoothly and gradually expanded from bottom to top. The smooth and gradually expanded cavity wall profile conforms to the metal It belongs to the upsetting flow law, which can make the metal blank 100 with a large aspect ratio gradually fill the cavity space from bottom to top along the cavity wall, and effectively avoid the instability and folding of the metal blank 100 with a large aspect ratio during the initial upsetting process; then the upsetting forming component is used to perform a second upsetting on the formed upsetting blank 200. Since the upsetting blank 200 is formed with one end larger than the other end and the blank surface between the large end and the small end is a circular gradually expanding curved surface, and the large end is placed downward, it can effectively avoid the instability and folding of the upsetting blank 200 during the second upsetting process, and further ensure the forming quality.
[0054] In some embodiments, before the upsetting blank 200 is heated again, edge burrs on the upsetting blank 200 are removed to improve the forming quality of the second upsetting pass.
[0055] In some embodiments, before placing the high aspect ratio metal blank 100 into the pre-upsetting assembly, lubricant is applied to the hole wall of the blank limiting hole 211, the cavity wall of the pre-upsetting die cavity 221, and the working end of the first punch 1; and / or, before placing the upsetting blank 200 into the upsetting forming assembly, lubricant is applied to the cavity wall of the pre-upsetting die cavity 221 and the working end of the second punch 4, thereby ensuring the smoothness of the deformation and flow of the blank material.
[0056] The following is combined with Figures 1 to 6 The method for preparing a metal blank with a large aspect ratio by upsetting is further described below:
[0057] Prepare a high aspect ratio metal billet 100, specifically AZ80 magnesium alloy, with a size of φ180×1200 mm; heat the high aspect ratio metal billet 100 and the first and second pass upsetting preparation dies (i.e., the aforementioned pre-upsetting assembly and upsetting forming assembly) to a target forming temperature of 400°C and maintain the temperature; and assemble the first pass upsetting preparation die onto a press; see Figures 1 to 3 As shown, a metal blank 100 with a large aspect ratio that has been heated to a target forming temperature and kept warm is placed in the upper die body 21 and the lower die body 22. The press is controlled to drive the first punch 1 downward to upset the metal blank 100 with a large aspect ratio. The metal blank 100 with a large aspect ratio flows from bottom to top along the parabolic cavity (i.e., the aforementioned upsetting barrel section 2212 of the blank), gradually filling the parabolic cavity and the straight-wall cavity (i.e., the aforementioned cylindrical section 2213), thereby forming an upset blank 200. Figure 6 As shown, the total height of the upsetting blank 200 is 525 mm, the diameter of the large end is φ355 mm, the height of the straight wall near the large end is 60 mm, the diameter of the small end is φ180 mm, the height of the straight wall near the small end is 50 mm, and the transition arc radius between the straight wall at the small end and the parabola is R500 mm; the ejection device (that is, the aforementioned first ejector 23) ejects the upsetting blank 200 from the mold, removes the edge burrs, and heats it to the target forming temperature of 400°C, and assembles the second upsetting preparation mold onto the press; combined with Figures 4 and 5 The upsetting blank 200 heated to the target forming temperature is placed with its large end facing downward into the upsetting forming cavity 31. The press is controlled to drive the second punch 4 downward to upset the upsetting blank 200 for two passes. The upsetting blank 200 will gradually fill the upsetting forming cavity 31 from top to bottom to form a target size of φ375×276.5mm.
[0058] It is easy for those skilled in the art to understand that, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.
[0059] The above description is merely 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 shall be included within the scope of protection of the present invention. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.
Claims
1. A die for preparing metal blanks with a large aspect ratio by upsetting, characterized in that: The invention comprises a pre-upsetting assembly, wherein the pre-upsetting assembly comprises a first punch (1) and a prefabricated lower die, wherein the prefabricated lower die is composed of an upper die body (21) and a lower die body (22) that are buckled together, wherein the upper die body (21) has a blank limiting hole (211) passing through the upper and lower ends thereof, wherein the first punch (1) can pass through the blank limiting hole (211) from top to bottom, and the lower die body (22) has a blank limiting hole (211) passing through the upper and lower ends thereof. A pre-upsetting die cavity (221) is formed in the form of a rotating body. The pre-upsetting die cavity (221) includes, from bottom to top, a blank bottom end limiting barrel section (2211) and a blank upsetting barrel section (2212). The blank bottom end limiting barrel section (2211) and the blank upsetting barrel section (2212) are smoothly connected. The diameter of the blank upsetting barrel section (2212) is smoothly expanded from bottom to top.
2. The die for preparing metal blanks with a large aspect ratio by upsetting according to claim 1, characterized in that: On the longitudinal section of the blank upsetting barrel section (2212), the inner wall profile of the blank upsetting barrel section (2212) is a parabola.
3. The die for preparing metal blanks with a large aspect ratio by upsetting according to claim 1, characterized in that: The pre-upsetting die cavity (221) further comprises a cylindrical section (2213) located at one end of the blank upsetting cylinder section (2212) away from the blank bottom end limiting cylinder section (2211); the cylindrical section (2213) is smoothly connected to the blank upsetting cylinder section (2212), and the inner diameter of the cylindrical section (2213) is smaller than the final upsetting target diameter of the large aspect ratio metal blank (100).
4. The die for preparing metal blanks with a large aspect ratio by upsetting according to claim 3, characterized in that: It also includes an upsetting forming component, which includes a forming die (3) and a second punch (4). The forming die (3) has an upsetting forming cavity (31). The diameter of the upsetting forming cavity (31) is equal to the outer diameter of the second punch (4), and both are not less than the inner diameter of the cylindrical section (2213).
5. The die for preparing metal blanks with a large aspect ratio by upsetting according to claim 4, characterized in that: A first push rod (23) is provided on the bottom wall of the pre-upsetting die cavity (221), and a second push rod (32) is provided on the bottom wall of the upsetting forming cavity (31).
6. The die for preparing metal blanks by upsetting with a large aspect ratio according to any one of claims 1 to 4, characterized in that: The overall height of the pre-upsetting die cavity (221) is H, the overall height of the blank limiting hole (211) is h, the initial length of the large aspect ratio metal blank (100) is L, H+h≥L, and when the large aspect ratio metal blank (100) is placed in the pre-upsetting assembly and is not upset, the volume of the portion of the large aspect ratio metal blank (100) in the blank limiting hole (211) is not greater than the volume of the cavity portion of the pre-upsetting die cavity (221).
7. The die for preparing a metal blank by upsetting it with a large aspect ratio according to any one of claims 1 to 4, characterized in that: The diameter of the large aspect ratio metal blank (100) is D, the diameter of the blank limiting hole (211) is d1, the diameter of the blank bottom limiting barrel section (2211) is d2, and d1=d2=D+1mm.
8. The die for preparing metal blanks by upsetting with a large aspect ratio according to any one of claims 1 to 4, characterized in that: The buckling surfaces of the upper mold body (21) and the lower mold body (22) are provided with concave and convex positioning structures.
9. A method for preparing a metal blank with a large aspect ratio by upsetting it using the metal blank upsetting die according to any one of claims 1 to 8, characterized in that: The steps include: The high aspect ratio metal blank (100), the pre-upsetting component and the upsetting forming component are heated to a target forming temperature and kept warm; Assembling the pre-upsetting assembly on a press, placing the large aspect ratio metal blank (100) into the pre-upsetting assembly through the blank limiting hole (211), and limiting the bottom end of the large aspect ratio metal blank (100) in the blank bottom limiting barrel section (2211); Controlling the operation of the press to drive the first punch (1) downward to apply force to the top of the large aspect ratio metal blank (100) so that the large aspect ratio metal blank (100) fills the pre-upsetting die cavity (221) from bottom to top along the cavity wall profile of the pre-upsetting die cavity (221), thereby preparing an upsetting blank (200) with a smaller lower end and a larger upper end; The upsetting blank (200) is heated again to the target forming temperature and then placed into the upsetting forming assembly assembled on the press, with the large end and the small end of the upsetting blank (200) positioned downward; The press is controlled to drive the second punch (4) downward to apply force to the small end of the upsetting blank (200) until the upsetting blank (200) fills the forming space formed between the second punch (4) and the upsetting forming cavity (31) from top to bottom, thereby preparing a formed part of a target size.
10. The method for preparing a metal blank by upsetting a large aspect ratio according to claim 9, characterized in that: Before the upsetting blank (200) is heated again, the edge burrs on the upsetting blank (200) are removed; and / or, before the high aspect ratio metal blank (100) is placed in the pre-upsetting assembly, lubricant is applied to the hole wall of the blank limiting hole (211), the cavity wall of the pre-upsetting die cavity (221), and the working end of the first punch (1); and / or, before the upsetting blank (200) is placed in the upsetting forming assembly, lubricant is applied to the cavity wall of the pre-upsetting die cavity (221) and the working end of the second punch (4).