A device and method for upsetting-extrusion repeated cycle forming

Abstract

The present invention discloses an apparatus and method for repeated upsetting and extrusion forming, belonging to the field of metal forging technology. The method comprises the following steps: providing a backing plate; an upper die lifting cylinder driving an upper die guide rod downward to press the upper die slide against the lower die slide; placing a blank into the cavity of the upper and lower die slides; a main pressure cylinder driving a punch downward to press the punch into the upper mold cavity, thereby pressing the blank in the upper mold cavity into the lower mold cavity for upsetting; after a single upsetting is completed, the main pressure cylinder drives the punch upward to extract the punch from the upper mold cavity and reset it, and then the upper die lifting cylinder lifts and resets the upper die slide; a lower die lifting cylinder drives the lower die guide rod to press the lower die slide, and an ejection cylinder pushes the backing plate upward to eject the upset blank from the lower mold cavity. The apparatus and method of the present invention can solve technical problems existing in existing closed guide cylinder extrusion equipment, such as easy breaking of connecting bolts, low working efficiency, and complex operation.

Description

Technical Field

[0001] The present invention relates to the technical field of metal forging, in particular to a device and method for upsetting-extrusion repeated cycle forming. Background Art

[0002] In the field of metal forging, especially for the microstructure refinement and performance improvement of light alloys, the traditional method relies on upsetting operations on the forging hammer to break up the internal coarse grain structure and refine the grains. However, for light alloys, due to the limitations of the casting process, the diameter (d0) of the cast rod has a certain upper limit. In order to obtain large-sized forgings or forgings, while keeping the d0 value unchanged, the only way to increase its volume is to increase the length (L0) of the forging billet. However, when the L / d0 ratio of the forging billet exceeds 3, the cast rod will become unstable during the upsetting process. Figure 1 , resulting in the inability to form qualified forging billets.

[0003] In order to solve the upsetting problem under the condition of large height-to-diameter ratio (L0 / d0>10), the existing technology adopts a closed guide tube structure. In this structure, the cast rod is subjected to repeated upsetting and extrusion operations under the constraints of the guide tube on all sides to achieve the goal of refining the structure and improving the performance. However, the existing closed guide tube adopts the traditional mold installation method for installation. Figure 2 , that is, using bolts 3' to connect the upper guide cylinder 1' and the lower guide cylinder 2' together, this method has at least the following problems during operation:

[0004] (1) Insufficient structural reliability: When the material 4' flows upward in the cavity, the axial tension generated by the dynamic load can reach thousands of tons. The tensile strength of the existing M24-M36 grade connecting bolts cannot meet the working conditions, and thread slippage or bolt breakage are prone to occur, resulting in forced interruption of the forming process.

[0005] (2) Low process conversion efficiency: Multiple forming steps require repeated disassembly and assembly of the mold. The specific operation process includes: removing the connecting bolts → separating the mold components → demolding the blank → inverting the mold and reassembling → re-tightening the bolts. This process takes 25-40 minutes per time and there is a risk of loss of mold positioning accuracy;

[0006] (3) The temperature of the blank dissipates quickly after demolding, and it must be reheated between passes, which leads to grain growth and the segregation and coarsening of some precipitated phases at the grain boundaries, greatly affecting the key properties of the blank such as strength and plasticity. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for repeated cyclic forming of upsetting and extrusion, so as to solve the technical problems of the existing closed guide barrel extrusion equipment, such as easy breaking of connecting bolts, low working efficiency and complicated operation.

[0008] To achieve the above-mentioned object, the present invention provides a method for upsetting-extrusion repeated cycle forming, which relates to an apparatus for upsetting-extrusion repeated cycle forming, the apparatus comprising a frame, on which an upper die slide, a lower die slide, a punch, and an ejection mechanism are provided;

[0009] The side of the upper die slide is connected to the output end of the upper die lifting cylinder through the upper die guide rod and is driven by the upper die lifting cylinder to slide up and down;

[0010] The side of the lower die slide is connected to the output end of the lower die lifting cylinder through the lower die guide rod and is driven by the lower die lifting cylinder to slide up and down;

[0011] The upper die slider has an upper mold cavity, and the lower die slider has a lower mold cavity, and the diameter of the upper mold cavity is smaller than the diameter of the lower mold cavity. When the upper mold cavity and the lower mold cavity are connected, the two together form a forming cavity for upsetting the blank;

[0012] The punch is located above the upper die slide and is driven downward or upward by the main pressure cylinder to press into or out of the upper die cavity.

[0013] The ejection mechanism includes a backing plate and an ejection cylinder. The backing plate is located below the lower mold slider and is driven upward or downward by the ejection cylinder to enter and exit the lower mold cavity.

[0014] The method comprises the following steps:

[0015] S1. Place the pad at the bottom of the lower mold cavity of the lower mold slider;

[0016] S2, the telescopic rod of the upper die lifting cylinder extends, driving the upper die guide rod downward to press the upper die slide against the lower die slide, so that the upper mold cavity and the lower mold cavity are connected;

[0017] S3, placing the blank into the cavity of the upper die slider and the lower die slider;

[0018] S4, the telescopic rod of the main pressure cylinder extends to push the punch downward, pressing the punch into the upper mold cavity, and then pressing the blank in the upper mold cavity into the lower mold cavity for upsetting;

[0019] S5. After a single upsetting is completed, the telescopic rod of the main pressure cylinder retracts to drive the punch upward, pulls the punch out of the upper mold cavity and resets it. Then the telescopic rod of the upper mold lifting cylinder retracts to lift and reset the upper mold slide.

[0020] Finally, the lower die lifting cylinder drives the lower die guide rod to press the lower die slide, and the telescopic rod of the ejection cylinder extends to push the pad up to eject the upset blank from the lower mold cavity.

[0021] Furthermore, the method can also realize multiple cycles of upsetting the blank, and the specific steps are as follows:

[0022] S1. Place the pad at the bottom of the lower mold cavity of the lower mold slider;

[0023] S2, the telescopic rod of the upper die lifting cylinder extends, driving the upper die guide rod downward to press the upper die slide against the lower die slide, so that the upper mold cavity and the lower mold cavity are connected;

[0024] S3, placing the blank into the cavity of the upper die slider and the lower die slider;

[0025] S4, the telescopic rod of the main pressure cylinder extends to push the punch downward, pressing the punch into the upper mold cavity, and then pressing the blank in the upper mold cavity into the lower mold cavity for upsetting;

[0026] S5. The lower die lifting cylinder drives the lower die guide rod to press the lower die slide. The telescopic rod of the ejection cylinder extends to push the pad upward, ejecting the upset blank from the lower die cavity into the upper die cavity, turning the upset blank into a fine blank again. Then the ejection cylinder retracts to drive the pad down and reset.

[0027] S6. Repeat S4 and S5 several times until the structure and performance of the blank meet the requirements and then stop working.

[0028] Furthermore, vertically extending slide grooves are provided on both sides of the frame;

[0029] One end of the upper die guide rod is connected to the end of the telescopic rod of the upper die lifting cylinder, and the other end vertically passes through the slide groove and is connected to the upper die slide block;

[0030] One end of the lower die guide rod is connected to the end of the telescopic rod of the lower die lifting cylinder, and the other end vertically passes through the slide groove and is connected to the lower die slide block;

[0031] When the upper die lifting cylinder and the lower die lifting cylinder are working, the guide rod moves in the corresponding slide groove and drives the connected slider to move at the same time.

[0032] Furthermore, the frame is a rectangular frame structure consisting of an upper crossbeam, two vertical plates and a lower crossbeam.

[0033] Furthermore, the main pressure oil cylinder is arranged on the upper crossbeam, the telescopic rod of the main pressure oil cylinder is connected to an upper slide plate, and the upper end of the punch is connected to the lower end of the upper slide plate;

[0034] The ejection mechanism is arranged on the lower crossbeam, the ejection oil cylinder in the ejection mechanism is arranged on the lower crossbeam, the telescopic rod of the ejection oil cylinder faces the lower mold cavity, and the lower end of the pad is connected to the telescopic rod of the ejection oil cylinder.

[0035] Furthermore, the upper mold slider is composed of an upper model, a first stress ring and a first slider, wherein an upper model cavity is formed in the upper model, the first stress ring is sleeved on the outer periphery of the upper model, the first slider is sleeved on the outer periphery of the first stress ring, and a first screw hole for connecting with the upper mold guide rod is provided in the middle of both sides of the first slider.

[0036] Furthermore, the lower mold slider is composed of a lower model, a second stress ring and a second slider, wherein a lower model cavity is formed in the lower model, the second stress ring is sleeved on the outer periphery of the lower model, the second slider is sleeved on the outer periphery of the second stress ring, and a second screw hole for connecting with the lower mold guide rod is provided in the middle of both sides of the second slider.

[0037] Furthermore, the main pressure oil cylinder and the ejection oil cylinder both adopt oil cylinders with a rated pressure greater than 3000 tons.

[0038] Furthermore, each slider is driven by at least two sets of left and right driving mechanisms, and the left and right driving mechanisms are symmetrically arranged on the frame.

[0039] The present invention discloses an apparatus for repeated cycle forming of upsetting and extrusion, comprising a frame, on which an upper die slide, a lower die slide, a punch and an ejection mechanism are provided;

[0040] The side of the upper die slide is connected to the output end of the upper die lifting cylinder through the upper die guide rod and is driven by the upper die lifting cylinder to slide up and down;

[0041] The side of the lower die slide is connected to the output end of the lower die lifting cylinder through the lower die guide rod and is driven by the lower die lifting cylinder to slide up and down;

[0042] The upper die slider has an upper mold cavity, and the lower die slider has a lower mold cavity, and the diameter of the upper mold cavity is smaller than the diameter of the lower mold cavity. When the upper mold cavity and the lower mold cavity are connected, the two together form a forming cavity for upsetting the blank;

[0043] The punch is located above the upper die slide and is driven downward or upward by the main pressure cylinder to press into or out of the upper die cavity.

[0044] The ejection mechanism includes a pad and an ejection cylinder. The pad is located below the lower mold slider and is driven upward or downward by the ejection cylinder to enter and exit the lower mold cavity.

[0045] After adopting the above solution, the beneficial effects of the present invention are:

[0046] 1. High mold closing stability and safety: After the upper mold slider and the lower mold slider of the present invention are closed, under the action of hundreds of tons of pressure, the horizontal gap between the two mold sliders after mold closing will not overflow the material during the upsetting and extrusion process, and at the same time, it also overcomes the risk of bolts being easily broken in the traditional method.

[0047] 2. Simplify the demoulding process: The present invention adopts a multi-slide design. Under the control of the oil cylinder, the upper and lower mold slides can be easily separated. At the same time, with the assistance of the ejection mechanism, the upsetting blank can be easily ejected upward, which greatly simplifies the demoulding process, reduces the complexity of equipment operation, and significantly improves work efficiency.

[0048] 3. The multi-slide design can also solve the problem of mold sticking during demolding. For example, the pressure of the main pressure cylinder is used to make the punch press against the head of the billet. Combined with the up and down movement of the upper die slide, this effectively prevents the billet from sticking in the upper mold cavity, ensuring that the billet can move up and down freely, solving the demolding problem of thin cast bars after upsetting.

[0049] 4. The mold of the present invention is simple and can be used for repeated upsetting of billets with a large aspect ratio (L0 / d0>10). It has reliable strength and can withstand large-tonnage extrusion operations, and has a long mold life.

[0050] 5. This invention utilizes a "single-fire forming" process, meaning all upsetting and extrusion passes are completed after a single heating of the blank. Through the coordinated movement of multiple slides, the blank is continuously deformed within the die, eliminating the need for intermediate demolding and reheating. This prevents grain growth and hard phase segregation, while also eliminating the energy consumption and time waste associated with traditional multi-pass processing.

[0051] After each upsetting, the blank is quickly transferred to the upper mold cavity by the ejection mechanism to continue the next extrusion pass. This continuous deformation mechanism ensures that the blank is always kept at a high temperature, maintaining the metal's plastic deformation ability.

[0052] 6. The present invention is applicable to the extrusion of various cast rods. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is the instability phenomenon that occurs during the upsetting of blanks using traditional technology;

[0054] Figure 2 This is a schematic diagram of the traditional upsetting die structure (bolts fix the upper and lower guide cylinders);

[0055] Figure 3 It is a structural schematic diagram of an upsetting extrusion forming device according to an embodiment of the present invention;

[0056] Figure 4 yes Figure 3 Left view of;

[0057] Figure 5 This is a schematic structural diagram of an upper die slider according to an embodiment of the present invention;

[0058] Figure 6 yes Figure 5 Left view of;

[0059] Figure 7 This is a schematic structural diagram of an upper die slider according to an embodiment of the present invention;

[0060] Figure 8 yes Figure 7 Side view;

[0061] Figure 9 1 is a schematic structural diagram of an upsetting extrusion forming device according to an embodiment of the present invention (upsetting state);

[0062] Figure 10 This is a single upsetting state diagram of an embodiment of the present invention;

[0063] Figure 11 This is a state diagram of multiple cycle upsetting according to an embodiment of the present invention;

[0064] Figure 12 The microstructure diagrams of the grains during upsetting using the method of the present invention (a and b) and the traditional method (c and d);

[0065] Figure 13 This is a comparison diagram of stress and strain when a blank is stretched using the method of the present invention (A) and the traditional method (B).

[0066] Description of labels:

[0067] 1. Frame; 11. Upper beam; 12. Vertical plate; 121. Slide; 13. Lower beam;

[0068] 2. Upper mold slider; 21. Upper mold; 22. First stress ring; 23. First slider; 231. First screw hole; 24. Upper mold cavity;

[0069] 3. Lower mold slider; 31. Lower mold; 32. Second stress ring; 33. Second slider; 331. Second screw hole; 34. Lower mold cavity;

[0070] 4. Upper die guide rod; 5. Upper die lifting cylinder;

[0071] 6. Lower die guide rod; 7. Lower die lifting cylinder;

[0072] 8. Punch; 9. Upper slide; 10. Main pressure cylinder;

[0073] 14. Ejector mechanism; 141. Pad; 142. Ejector cylinder;

[0074] 15. Blank. DETAILED DESCRIPTION

[0075] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0076] The present invention provides a method for upsetting-extrusion repeated cycle forming, the method relates to an apparatus for upsetting-extrusion repeated cycle forming, such as Figures 3 to 11 As shown, the equipment includes a frame 1, a rectangular structure consisting of an upper crossbeam 11, two left and right uprights 12, and a lower crossbeam 13. This integrated frame 1 design not only enhances the equipment's strength but also ensures stability and reliability during high-intensity upsetting and extrusion operations. The frame 1 is equipped with an upper die slide 2, a lower die slide 3, a punch 8, and an ejection mechanism 14. These structures are crucial for upsetting and extruding the billet 15. The upper die slide 2 and lower die slide 3 serve as the movable die structure.

[0077] <Upper die slide 2>

[0078] like Figure 3 As shown, the upper die slide 2 is located within the frame 1. The sides of the upper die slide 2 are connected to the upper die lift cylinder 5 via upper die guide rods 4, and are driven by the upper die lift cylinders 5 to slide up and down. A single upper die lift cylinder 5, serving as a driving source, is located on each left and right side of the upper portion of the frame 1. Each upper die lift cylinder 5 is connected to an upper die guide rod 4. These two upper die guide rods 4 are tightly connected to the left and right sides of the upper die slide 2, respectively, forming a highly symmetrical and stable drive structure.

[0079] Specifically, the frame 1 has vertically extending slots 121 on both of its vertical plates 12. One end of the upper die guide rod 4 is connected to the lower end of the telescopic rod of the upper die lift cylinder 5. The other end of the upper die guide rod 4 extends vertically through the slots 121 and connects to the side of the upper die slide 2. When the upper die lift cylinder 5 is in operation, the upper die guide rod 4 moves within the corresponding slots 121, thereby driving the connected upper die slide 2 to move.

[0080] Further, refer to Figure 5 The upper die slider 2 is composed of an upper mold 21, a first stress ring 22 and a first slider 23, wherein an upper mold cavity 24 is formed in the upper mold 21, and the first stress ring 22 is sleeved on the outer periphery of the upper mold 21. During the process of upsetting-extrusion repeated cycles, the mold needs to withstand huge pressure and impact force, and the presence of the stress ring can effectively disperse these forces to prevent the mold from being deformed or damaged due to excessive force. The first slider 23 is sleeved on the outer periphery of the first stress ring 22, providing additional protection and stability for the entire upper die slider 2. At least one first screw hole 231 is provided in the middle of the left and right sides of the first slider 23, refer to Figure 6 The lower end of the L-shaped upper mold guide rod 4 is connected to the first screw hole 231.

[0081] <Lower die slide 3>

[0082] like Figure 3As shown, similar to the upper die slide 2, the lower die slide 3 is also located within the frame 1. The lower die slide 3 is connected to the lower die lift cylinder 7 via the lower die guide rod 6 and is driven by the lower die lift cylinder 7 to slide up and down. A lower die lift cylinder 7, serving as a driving source, is located on each left and right side of the lower portion of the frame 1. Each lower die lift cylinder 7 is connected to a lower die guide rod 6. These two lower die guide rods 6 are tightly connected to the left and right sides of the lower die slide 3, respectively, forming a highly symmetrical and stable drive structure.

[0083] Specifically, one end of the lower die guide rod 6 is vertically connected to the telescopic rod of the lower die lifting cylinder 7, and the other end of the lower die guide rod 6 vertically passes through the chute 121 and is connected to the side of the lower die slide 3. When the lower die lifting cylinder is working, the lower die guide rod 6 moves in the corresponding chute 121, thereby driving the connected lower die slide 3 to move.

[0084] Further, refer to Figure 7 The structure of the lower mold slider 3 is similar to that of the upper mold slider 2. The lower mold slider 3 is composed of a lower mold 31, a second stress ring 32 and a second slider 33. A lower mold cavity 34 is formed in the lower mold 31. The second stress ring 32 is sleeved on the outer periphery of the lower mold 31. The second slider 33 is sleeved on the outer periphery of the second stress ring 32. At least one second screw hole 331 is provided in the middle of the left and right sides of the second slider 33. Figure 6 The upper end of the L-shaped lower mold guide rod 6 is connected to the second screw hole 331.

[0085] like Figure 3 As shown, the upper die slider 2 and the lower die slider 3 serve as the die structure. The upper die slider 2 has an upper mold cavity 24, and the lower die slider 3 has a lower mold cavity 34. The diameter d0 of the upper mold cavity 24 is smaller than the diameter d1 of the lower mold cavity 34. With this condition met, the diameters of the upper mold cavity 24 and the lower mold cavity 34 can be determined based on the bar size and the actual upsetting requirements. After the upper die slider 2 and the lower die slider 3 are closed, the upper mold cavity 24 and the lower mold cavity 34 are connected, and together they form the forming cavity for upsetting the blank 15.

[0086] <Punch 8>

[0087] The punch 8 is located above the upper die slider 2 , and the punch 8 and the upper mold cavity 24 of the upper die slider 2 are of matching shapes, and the two cooperate to form a concave-convex die 8 structure for extruding the blank 15 .

[0088] like Figure 3 As shown, the upper crossbeam 11 of the frame 1 is provided with a main pressure cylinder 10 for driving the punch 8, with the telescopic rod of the main pressure cylinder 10 facing downward. The lower end of the telescopic rod of the main pressure cylinder 10 is fixedly connected to an upper slide 9, which is used to fix the punch 8. The upper end of the punch 8 is fixedly connected to the lower end of the upper slide 9.

[0089] When the main pressure cylinder 10 begins operating, its telescopic rod extends or retracts as needed. The extended rod pushes the upper slide 9 downward, which in turn drives the punch 8 precisely into the upper mold cavity 24, extruding and forming the blank 15. Conversely, when the rod retracts, it pulls the upper slide 9 upward, pulling the punch 8 out of the upper mold cavity 24, completing a complete operating cycle. This design not only ensures the stability and precision of the punch 8's movement but also significantly improves mold efficiency and forming quality.

[0090] <Ejector mechanism 14>

[0091] like Figure 3 and Figure 4 As shown, the ejection mechanism 14 is disposed below the lower mold slide 3 and comprises a backing plate 141 and an ejection cylinder 142. The ejection cylinder 142 is mounted on the lower crossbeam 13, with the lower end of the backing plate 141 connected to the telescopic rod of the ejection cylinder 142. When the ejection cylinder 142 is in operation, its telescopic rod drives the backing plate 141 downward or upward, pressing it into or out of the lower mold cavity 34. The ejection mechanism 14 not only ejects the blank 15 upward from the mold cavity but also cooperates with the punch 8 to extrude the blank 15, ensuring higher forming accuracy and better surface quality.

[0092] The main pressure cylinder 10 and ejector cylinder 142 used in this application are both rated at greater than 3,000 tons to ensure sufficient working pressure during mold operation and meet the requirements of high-strength and high-precision forming. The rated pressures of the upper mold lift cylinder 5 and the lower mold lift cylinder 7 are sufficient to drive the corresponding sliders.

[0093] The method for repeated cycle forming of upsetting and extrusion of the present invention comprises the following steps (refer to Figure 3 and Figure 10 ):

[0094] The specific steps of single-pass upsetting the blank 15 are:

[0095] S1. First, place the lower mold slider 3 and the pad 141 on the lower crossbeam 13 of the frame 1 so that the pad 141 is located at the bottom of the lower mold cavity 34;

[0096] S2: The telescopic rod of the upper die lift cylinder 5 extends, driving the upper die guide rod 4 downward to press the upper die slide 2 against the lower die slide 3, closing the mold. At this point, the upper mold cavity 24 and the lower mold cavity 34 are in a connected state. After the upper die slide 2 and the lower die slide 3 are closed, hundreds of tons of pressure ensure that the horizontal gap after the mold is closed does not overflow during the upsetting and extrusion process, while also eliminating the risk of bolt breakage in traditional methods.

[0097] S3, placing the blank 15 (a cast rod having a diameter smaller than that of the upper mold cavity 24) into the cavities of the upper mold slider 2 and the lower mold slider 3;

[0098] S4, the telescopic rod of the main pressure oil cylinder 10 extends to push the upper slide 9 downward, pressing the punch 8 into the upper mold cavity 24, and then pressing the blank 15 in the upper mold cavity 24 into the lower mold cavity 34 for upsetting. After upsetting, Figure 3 and Figure 10 As shown, the relationship between the length L0 of the forging blank, the length L1 of the upper mold cavity 24, the length L2 of the lower mold cavity 34, and the height h of the pad 141 is: L0=L1+L2-h.

[0099] S5. Demolding after upsetting: the telescopic rod of the main pressure cylinder 10 retracts to drive the upper slide plate 9 upward, pulling the punch 8 out of the upper mold cavity 24 and resetting it. Then the telescopic rod of the upper mold lifting cylinder 5 retracts to lift and reset the upper mold slide 2. Finally, the lower mold lifting cylinder 7 drives the lower mold guide rod 6 to press the lower mold slide 3. The telescopic rod of the ejection cylinder 142 extends to push the pad 141 upward to eject the upset blank 15 (cast blank) from the lower mold cavity 34.

[0100] The multi-slider design of the present invention easily separates the upper and lower die slides 3. Simultaneously, with the assistance of the ejection mechanism 14, the upset billet 15 can be easily ejected upward, greatly simplifying the demolding process, reducing the complexity of equipment operation, and significantly improving work efficiency. This multi-slider design also solves the problem of mold sticking during demolding. For example, by using the pressure of the main pressure cylinder 10 to force the punch 8 against the head of the billet 15, combined with the up and down movement of the upper die slide 2, the billet 15 is effectively prevented from sticking within the upper mold cavity 24, ensuring that the billet 15 can move freely up and down, thus solving the demolding problem of fine cast bars after upsetting.

[0101] In addition, the mold of the present invention is simple and can perform repeated upsetting with a large height-to-diameter ratio L0 / d0>10. It has reliable strength and can withstand large-tonnage extrusion operations, and has a long mold life.

[0102] The method of the present invention can also realize multiple cycles of upsetting the blank 15, and the specific steps are as follows (refer to Figure 11 ):

[0103] S1. First, place the lower mold slider 3 and the pad 141 on the lower crossbeam 13 of the frame 1 so that the pad 141 is located at the bottom of the lower mold cavity 34;

[0104] S2, the telescopic rod of the upper mold lifting cylinder 5 is extended, driving the upper mold guide rod 4 downward to press the upper mold slide 2 against the lower mold slide 3 to close the mold. At this time, the upper mold cavity 24 and the lower mold cavity 34 are in a connected state;

[0105] S3, placing the blank 15 (a cast rod having a diameter smaller than that of the upper mold cavity 24) into the cavities of the upper mold slider 2 and the lower mold slider 3;

[0106] S4, the telescopic rod of the main pressure cylinder 10 extends to push the upper slide 9 downward, pressing the punch 8 into the upper mold cavity 24, and then pressing the blank 15 in the upper mold cavity 24 into the lower mold cavity 34 for initial upsetting;

[0107] S5, the lower die lifting oil cylinder 7 drives the lower die guide rod 6 to press the lower die slide 3, and the telescopic rod of the ejection oil cylinder 142 extends to push the pad 141 upward, ejecting the upset blank 15 from the lower mold cavity 34 into the upper mold cavity 24, so that the upset blank 15 becomes a fine blank 15 again. Figure 11 Then the ejection cylinder 142 retracts to drive the pad 141 downward to reset;

[0108] S6. Circular upsetting: Repeat steps S4 and S5 multiple times to upset and refine the blank 15 again until the structure and performance of the blank 15 meet the requirements, and then stop working.

[0109] In existing conventional methods, to further extrusion-deform the upset blank 15 to refine its microstructure, the operator must first remove the upper and lower guide cylinders, then flip the workpiece and re-secure it. Furthermore, a backing ring must be added below the guide cylinder to elevate the blank 15, allowing the punch 8 to descend and compact against the backing plate 141, thereby completing the extrusion process from coarse to fine. This series of steps is not only complex and cumbersome, but also lengthy, resulting in low production efficiency. More critically, the temperature of the blank 15 drops rapidly due to the multiple loading and unloading and flipping steps, which is particularly detrimental for light alloy materials with high thermal sensitivity. Therefore, conventional multi-pass processing methods struggle to successfully complete the entire deformation process from upsetting to extrusion in a single heating cycle (one heat). In contrast, the method of the present invention not only significantly simplifies the process and improves production efficiency, but also effectively maintains the temperature of the blank 15, making it possible to complete repeated upsetting and extrusion of difficult-to-process materials such as light alloys with a single heating cycle.

[0110] like Figure 12 As shown, (a) and (b) are the grain microstructure diagrams when the blank is upset by the method of the present invention. It can be seen from the diagrams that the grains are refined and the precipitated phase is not coarse; while (c) and (d) are the grain microstructure diagrams when the blank is upset by the traditional method. It can be seen from the diagrams that the grains are coarse and the precipitated phase at the grain boundary is coarse;

[0111] Figure 13The following are stress-strain curves for magnesium alloy billets produced during tensile testing. Curve A represents the method of the present invention, while Curve B represents the conventional method. As can be seen from the figure, Curve A exhibits a tensile strength of 320 MPa and an elongation of 14%, while Curve B exhibits a tensile strength of 260 MPa and an elongation of 8%. The method of the present invention exhibits higher strength and ductility in billet production, resulting in superior mechanical properties compared to the conventional method represented by Curve B.

[0112] To further illustrate various embodiments, the present invention is provided with accompanying drawings. These drawings form part of the present disclosure and are primarily used to illustrate the embodiments and, in conjunction with the relevant description in the specification, to explain the operating principles of the embodiments. By referring to these drawings, one of ordinary skill in the art will understand other possible embodiments and the advantages of the present invention. The components in the figures are not drawn to scale, and similar reference numerals are generally used to represent similar components.

[0113] At the same time, the directions such as front, back, left, and right involved in this embodiment are only used as a reference for directions and do not represent directions in actual use. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0114] The above description is only a preferred embodiment of the present invention and is not intended to limit the design of this case. Any equivalent changes made based on the key design of this case shall fall within the scope of protection of this case.

Claims

1. A method for repeated upsetting-extrusion forming, characterized in that: The method relates to a device for repeated cyclic forming of upsetting and extrusion, which comprises a frame on which an upper die slide, a lower die slide, a punch and an ejection mechanism are provided; The side of the upper die slide is connected to the output end of the upper die lifting cylinder through the upper die guide rod and is driven by the upper die lifting cylinder to slide up and down; The side of the lower die slide is connected to the output end of the lower die lifting cylinder through the lower die guide rod and is driven by the lower die lifting cylinder to slide up and down; The upper die slider has an upper mold cavity, and the lower die slider has a lower mold cavity, and the diameter of the upper mold cavity is smaller than the diameter of the lower mold cavity. When the upper mold cavity and the lower mold cavity are connected, the two together form a forming cavity for upsetting the blank; The punch is located above the upper die slide and is driven downward or upward by the main pressure cylinder to press into or out of the upper die cavity. The ejection mechanism includes a backing plate and an ejection cylinder. The backing plate is located below the lower mold slider and is driven upward or downward by the ejection cylinder to enter and exit the lower mold cavity. The main pressure cylinder and the ejection cylinder are both cylinders with a rated pressure greater than 3000 tons. All upsetting and extrusion passes are completed after a single heating, including the following steps: S1. Place the pad at the bottom of the lower mold cavity of the lower mold slider; S2, the telescopic rod of the upper die lifting cylinder extends, driving the upper die guide rod downward to press the upper die slide against the lower die slide, so that the upper mold cavity and the lower mold cavity are connected; S3, placing the blank into the cavity of the upper die slider and the lower die slider; S4, the telescopic rod of the main pressure cylinder extends to push the punch downward, pressing the punch into the upper mold cavity, and then pressing the blank in the upper mold cavity into the lower mold cavity for upsetting; S5. The lower die lifting cylinder drives the lower die guide rod to press the lower die slide. The telescopic rod of the ejection cylinder extends to push the pad upward, ejecting the upset blank from the lower die cavity into the upper die cavity, turning the upset blank into a fine blank again. Then the ejection cylinder retracts to drive the pad down and reset. S6. Repeat steps S4 and S5 multiple times until the mechanical properties of the blank reach a tensile strength ≥ 320 MPa and an elongation ≥ 14%, and at the same time, the precipitated phase is not coarsened; S7 demolding uses the pressure of the main pressure cylinder to make the punch press against the head of the blank. The lower die lifting cylinder drives the lower die guide rod to press the lower die slide. The telescopic rod of the upper die lifting cylinder retracts to lift and reset the upper die slide. Finally, the telescopic rod of the ejection cylinder extends to push the pad up to eject the upset blank from the lower mold cavity.

2. The method for repeated upsetting-extrusion forming according to claim 1, characterized in that: Both sides of the frame are provided with vertically extending slide grooves; One end of the upper die guide rod is connected to the end of the telescopic rod of the upper die lifting cylinder, and the other end vertically passes through the slide groove and is connected to the upper die slide block; One end of the lower die guide rod is connected to the end of the telescopic rod of the lower die lifting cylinder, and the other end vertically passes through the slide groove and is connected to the lower die slide block; When the upper die lifting cylinder and the lower die lifting cylinder are working, the guide rod moves in the corresponding slide groove and drives the connected slider to move at the same time.

3. The method for repeated upsetting-extrusion forming according to claim 1, characterized in that: The frame is a rectangular frame structure consisting of an upper crossbeam, two vertical plates and a lower crossbeam.

4. The method for repeated upsetting-extrusion forming according to claim 3, characterized in that: The main pressure oil cylinder is arranged on the upper crossbeam, the telescopic rod of the main pressure oil cylinder is connected to an upper slide plate, and the upper end of the punch is connected to the lower end of the upper slide plate; The ejection mechanism is arranged on the lower crossbeam, the ejection oil cylinder in the ejection mechanism is arranged on the lower crossbeam, the telescopic rod of the ejection oil cylinder faces the lower mold cavity, and the lower end of the pad is connected to the telescopic rod of the ejection oil cylinder.

5. The method for repeated upsetting-extrusion forming according to claim 1, characterized in that: The upper mold slider consists of an upper model, a first stress ring and a first slider, wherein an upper mold cavity is formed in the upper model, the first stress ring is sleeved on the outer periphery of the upper model, the first slider is sleeved on the outer periphery of the first stress ring, and the middle part of the two side surfaces of the first slider is provided with a first screw hole for connecting with the upper mold guide rod.

6. The method for repeated upsetting-extrusion forming according to claim 1, characterized in that: The lower mold slider consists of a lower model, a second stress ring and a second slider, wherein a lower mold cavity is formed in the lower model, the second stress ring is sleeved on the outer periphery of the lower model, the second slider is sleeved on the outer periphery of the second stress ring, and a second screw hole for connecting to the lower mold guide rod is provided in the middle of both sides of the second slider.

7. The method for repeated upsetting-extrusion forming according to claim 1, characterized in that: Each slider is driven by at least two sets of left and right driving mechanisms, and the left and right driving mechanisms are symmetrically arranged on the frame.

8. An apparatus for repeated cyclic forming of upsetting and extrusion, used in the forming method according to any one of claims 1 to 7, characterized in that: The utility model comprises a frame, on which an upper die slide, a lower die slide, a punch and an ejection mechanism are provided; The side of the upper die slide is connected to the output end of the upper die lifting cylinder through the upper die guide rod and is driven by the upper die lifting cylinder to slide up and down; The side of the lower die slide is connected to the output end of the lower die lifting cylinder through the lower die guide rod and is driven by the lower die lifting cylinder to slide up and down; The upper die slider has an upper mold cavity, and the lower die slider has a lower mold cavity, and the diameter of the upper mold cavity is smaller than the diameter of the lower mold cavity. When the upper mold cavity and the lower mold cavity are connected, the two together form a forming cavity for upsetting the blank; The punch is located above the upper die slide and is driven downward or upward by the main pressure cylinder to press into or out of the upper die cavity. The ejection mechanism includes a pad and an ejection cylinder. The pad is located below the lower mold slider and is driven upward or downward by the ejection cylinder to enter and exit the lower mold cavity.

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