Equipment and method for upsetting-extruding repeated circulation forming

Abstract

The invention discloses a device and method for upsetting-extruding repeated circulation forming, and belongs to the technical field of metal forging. The method comprises the following steps that a base plate is arranged; the upper die lifting oil cylinder drives the upper die guide rod to move downwards to press the upper die sliding block on the lower die sliding block; a blank is placed in a cavity of the upper die sliding block and a cavity of the lower die sliding block; the main pressure oil cylinder pushes the male die to move downwards, the male die is pressed into the upper die cavity, and then the blank in the upper die cavity is pressed into the lower die cavity for upsetting; after single upsetting is completed, the main pressure oil cylinder drives the male die to move upwards, the male die is pulled out of the upper die cavity and reset, and then the upper die lifting oil cylinder lifts and resets the upper die sliding block; the lower die jacking oil cylinder drives the lower die guide rod to press the lower die sliding block, and the ejection oil cylinder pushes the base plate to ascend so as to eject the upset blank out of the lower die cavity. According to the equipment and the method, the technical problems that a connecting bolt is easy to snap, the working efficiency is low, the operation is complicated and the like in the existing closed guide cylinder extrusion equipment can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal forging, and particularly relates to an apparatus and method for upsetting-extrusion repeated cyclic forming. Background Art

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

[0003] To solve the upsetting problem under the condition of a large height-to-diameter ratio (L0 / d0>10), the prior art adopts a closed guide cylinder structure. In this structure, the cast rod undergoes repeated upsetting-extrusion operations under the circumferential constraint conditions of the guide cylinder to achieve the goal of refining the microstructure and improving the properties. However, the existing closed guide cylinders adopt the traditional die installation method, refer to Figure 2 , that is, using bolts 3' to connect the upper guide cylinder 1' and the lower guide cylinder 2', and this method has at least the following problems during the working process: (1) Insufficient structural reliability: When the material 4' undergoes upward metal flow in the cavity, the axial tensile force generated by the dynamic load can reach thousands of tons, and the tensile strength of the existing M24-M36 grade connecting bolts is difficult to meet the working conditions, resulting in easy thread slipping or bolt fracture, and the forming process is forced to be interrupted; (2) Low process conversion efficiency: Multiple-pass forming requires repeated disassembly and assembly of the die. The specific operation process includes: removing the connecting bolts → separating the die components → blank demoulding → inverting the die for recombination → re-tightening the bolts. This process takes 25-40 minutes each time, and there is a risk of loss of die positioning accuracy; (3) The temperature of the blank dissipates quickly after demoulding, and it must be reheated between passes, resulting in grain growth and coarsening of partial precipitation phases at grain boundaries, which greatly affects the key properties such as the strength and plasticity of the blank. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for upsetting-extrusion repeated cyclic forming to solve the technical problems such as easy breakage of connecting bolts, low working efficiency, and complex operation existing in the existing closed guide cylinder extrusion equipment.

[0005] To achieve the above-mentioned purpose, the solution of the present invention is: a method for upsetting-extrusion repeated cycle forming, the method relates to a device for upsetting-extrusion repeated cycle forming, the device comprises a frame, an upper die slider, a lower die slider, a punch and an ejection mechanism are provided on the frame; The side of the upper die slide block 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 block 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, 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 the punch is driven downward or upward by the main pressure cylinder to press into or pull out of the upper mold cavity; The ejection mechanism includes a backing plate and an ejection cylinder. The backing plate is located below the lower mold slide block. The backing plate is driven upward or downward by the ejection cylinder to enter and exit the lower mold cavity. The method comprises the following steps: S1, placing a pad at the bottom of the lower mold cavity of the lower mold slide; S2, the telescopic rod of the upper die lifting cylinder extends, driving the upper die guide rod downward to press the upper die slide onto 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 oil 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. 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, and then the telescopic rod of the upper mold lifting cylinder retracts to lift and reset the upper mold slide; Finally, the lower die lifting cylinder drives the lower die guide rod to press the lower die slide block, and the telescopic rod of the ejection cylinder extends to push the pad up to eject the upset blank from the lower mold cavity.

[0006] Furthermore, the method can also realize multiple cycles of upsetting the blank, and the specific steps are as follows: S1, placing a pad at the bottom of the lower mold cavity of the lower mold slide; S2, the telescopic rod of the upper die lifting cylinder extends, driving the upper die guide rod downward to press the upper die slide onto 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 oil 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 mold lifting oil cylinder drives the lower mold guide rod to press against the lower mold slider, and the telescopic rod of the ejector oil cylinder extends to push the backing plate upward, ejecting the upset blank from the lower mold cavity into the upper mold cavity, making the upset blank become a thin blank again. Then the ejector oil cylinder retracts to drive the backing plate to descend and reset. S6. Repeat S4 and S5 multiple times until the structure and properties of the blank meet the requirements and then stop working.

[0007] Furthermore, vertical extending chutes are provided on both sides of the frame. One end of the upper mold guide rod is connected to the end of the telescopic rod of the upper mold lifting oil cylinder, and the other end vertically passes through the chute and is connected to the upper mold slider. One end of the lower mold guide rod is connected to the end of the telescopic rod of the lower mold lifting oil cylinder, and the other end vertically passes through the chute and is connected to the lower mold slider. When the upper mold lifting oil cylinder and the lower mold lifting oil cylinder work, the guide rod moves in the corresponding chute, and at the same time drives the connected slider to move.

[0008] Furthermore, the frame is a rectangular frame structure composed of an upper crossbeam, two vertical plates and a lower crossbeam.

[0009] 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 sliding plate, and the upper end of the punch is connected to the lower end of the upper sliding plate. The ejecting mechanism is arranged on the lower crossbeam. The ejector oil cylinder in the ejecting mechanism is arranged on the lower crossbeam, the telescopic rod of the ejector oil cylinder faces the lower mold cavity, and the lower end of the backing plate is connected to the telescopic rod of the ejector oil cylinder.

[0010] Furthermore, the upper mold slider is composed of an upper mold body, a first stress ring and a first slider. Among them, an upper mold cavity is formed in the upper mold body, the first stress ring is sleeved on the outer periphery of the upper mold body, the first slider is sleeved on the outer periphery of the first stress ring, and first screw holes for connecting with the upper mold guide rod are provided in the middle of both side surfaces of the first slider.

[0011] Furthermore, the lower mold slider is composed of a lower mold body, a second stress ring and a second slider. Among them, a lower mold cavity is formed in the lower mold body, the second stress ring is sleeved on the outer periphery of the lower mold body, the second slider is sleeved on the outer periphery of the second stress ring, and second screw holes for connecting with the lower mold guide rod are provided in the middle of both side surfaces of the second slider.

[0012] Furthermore, both the main pressure oil cylinder and the ejector oil cylinder adopt oil cylinders with a rated pressure greater than 3000 tons.

[0013] 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.

[0014] The present invention discloses a device for repeated cycle forming of upsetting and extrusion, comprising a frame, on which an upper die slider, a lower die slider, a punch and an ejection mechanism are arranged; The side of the upper die slide block 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 block 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, 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 the punch is driven downward or upward by the main pressure cylinder to press into or pull out of the upper mold 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.

[0015] After adopting the above scheme, the beneficial effects of the present invention are: 1. High mold closing stability and safety: After the upper mold slider and the lower mold slider of the present invention are molded together, under the action of hundreds of tons of pressure, it is ensured that 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.

[0016] 2. Simplify the demoulding process: The present invention adopts a multi-slider 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 roughened blank can be easily ejected upward, which greatly simplifies the demoulding process, reduces the complexity of equipment operation, and significantly improves work efficiency.

[0017] 3. The multi-slide design can also solve the problem of mold sticking during demoulding. For example, the pressure of the main pressure cylinder is used to make the punch press against the head of the billet, and combined with the up and down movement of the upper die slide, the billet is effectively prevented from sticking in the upper mold cavity, ensuring that the billet can move in and out freely, solving the demoulding problem of thin casting bars after upsetting.

[0018] 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.

[0019] 5. The present invention adopts the "one - fire forming" process, that is, the blank completes all passes of upsetting - extrusion forming after single - time heating. Through the coordinated movement of multiple sliders, the blank continuously deforms in the die, without intermediate demoulding and reheating, avoiding grain growth and hard - phase segregation, and also avoiding the energy consumption and time waste brought by traditional multi - pass processing.

[0020] After each upsetting, the blank is quickly transferred to the upper die cavity through the ejector mechanism and continues the next - pass extrusion. This continuous deformation mechanism ensures that the blank is always in a high - temperature state, maintaining the plastic deformation ability of the metal.

[0021] 6. The present invention is applicable to the extrusion of various casting rods. Brief Description of the Drawings

[0022] Figure 1 is the instability phenomenon occurring during the upsetting of the blank in the traditional technology; Figure 2 is the schematic structural diagram of the traditional upsetting die (the upper and lower guide cylinders are fixed by bolts); Figure 3 is the schematic structural diagram of the upsetting - extrusion forming equipment according to an embodiment of the present invention; Figure 4 is Figure 3 the left view of Figure 5 is the schematic structural diagram of the upper - die slider according to an embodiment of the present invention; Figure 6 is Figure 5 the left view of Figure 7 is the schematic structural diagram of the upper - die slider according to an embodiment of the present invention; Figure 8 is Figure 7 the side view; Figure 9 is the schematic structural diagram of the upsetting - extrusion forming equipment according to an embodiment of the present invention (in the upsetting state); Figure 10 is the diagram of the single - time upsetting state according to an embodiment of the present invention; Figure 11 is the diagram of the multi - cycle upsetting state according to an embodiment of the present invention; Figure 12 is the microscopic grain structure diagram when upsetting by the method of the present invention (a and b) and the traditional method (c and d); Figure 13 is the stress - strain comparison diagram when stretching the blank by the method of the present invention (A) and the traditional method (B).

[0023] Reference Numeral Explanation: 1. Frame; 11. Upper crossbeam; 12. Vertical plate; 121. Slide groove; 13. Lower crossbeam; 2. Upper die slider; 21. Upper die model; 22. First stress ring; 23. First slider; 231. First screw hole; 24. Upper die cavity; 3. Lower die slider; 31. Lower die model; 32. Second stress ring; 33. Second slider; 331. Second screw hole; 34. Lower die cavity; 4. Upper die guiding rod; 5. Upper die lifting oil cylinder; 6. Lower die guiding rod; 7. Lower die jacking oil cylinder; 8. Punch; 9. Upper slide plate; 10. Main pressure oil cylinder; 14. Ejector mechanism; 141. Backing plate; 142. Ejecting oil cylinder; 15. Blank. Specific implementation manner

[0024] The following is a detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments.

[0025] The present invention provides a method for upsetting-extrusion repeated cyclic forming, and this method relates to an apparatus for upsetting-extrusion repeated cyclic forming, such as Figures 3 to 11 shown. The apparatus includes a frame 1, and the frame 1 is a rectangular frame 1 structure composed of an upper crossbeam 11, two left and right vertical plates 12, and a lower crossbeam 13. This overall frame 1 design not only enhances the body strength of the apparatus but also ensures the stability and reliability during high-intensity upsetting-extrusion operations. The frame 1 is provided with an upper die slider 2, a lower die slider 3, a punch 8, and an ejector mechanism 14, and these structures are crucial for upsetting-extruding the blank 15. Among them, the upper die slider 2 and the lower die slider 3 serve as movable concave die structures.

[0026] <Upper die slider 2> As Figure 3 shown, the upper die slider 2 is located within the frame 1. The side of the upper die slider 2 is connected to the upper die lifting oil cylinder 5 through the upper die guiding rod 4 and is driven by the upper die lifting oil cylinder 5 to slide up and down. One upper die lifting oil cylinder 5 as a driving source is provided on each of the left and right sides of the upper part of the frame 1. Each upper die lifting oil cylinder 5 is connected to an upper die guiding rod 4, and these two upper die guiding rods 4 are respectively closely connected to the left and right sides of the upper die slider 2, forming a highly symmetric and stable driving structure.

[0027] Specifically, the frame 1 is provided with vertically extending chutes 121 on both of its vertical plates 12. One end of the upper die guiding rod 4 is connected to the lower end of the telescopic rod of the upper die lifting oil cylinder 5, and the other end of the upper die guiding rod 4 perpendicularly passes through the chute 121 and is connected to the side of the upper die slider 2. When the upper die lifting oil cylinder 5 works, the upper die guiding rod 4 moves within the corresponding chute 121, thereby driving the connected upper die slider 2 to move.

[0028] Furthermore, referring toFigure 5 , the upper die slider 2 is composed of an upper die model 21, a first stress ring 22 and a first slider 23. Among them, an upper die cavity 24 is formed inside the upper die model 21, and the first stress ring 22 is sleeved on the outer periphery of the upper die model 21. During the process of upsetting-extrusion repeated cyclic forming, the die needs to bear huge pressure and impact force, and the existence of the stress ring can effectively disperse these forces and prevent the die from deforming or being 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 each of the left and right side surfaces of the first slider 23. Refer to Figure 6 , the lower end of the L-shaped upper die guiding rod 4 is connected to the first screw hole 231.

[0029] <Lower die slider 3> As Figure 3 shown, similar to the upper die slider 2, the lower die slider 3 is also located inside the frame 1. The lower die slider 3 is connected to the lower die lifting oil cylinder 7 through the lower die guiding rod 6 and is driven by the lower die lifting oil cylinder 7 to slide up and down. One lower die lifting oil cylinder 7 as a driving source is provided on each of the left and right sides of the lower part of the frame 1. Each lower die lifting oil cylinder 7 is connected to a lower die guiding rod 6, and these two lower die guiding rods 6 are respectively tightly connected to the left and right sides of the lower die slider 3, forming a highly symmetrical and stable driving structure.

[0030] Specifically, one end of the lower die guiding rod 6 is vertically connected to the telescopic rod of the lower die lifting oil cylinder 7, and the other end of the lower die guiding rod 6 vertically passes through the chute 121 and is connected to the side of the lower die slider 3. When the lower die lifting oil cylinder works, the lower die guiding rod 6 moves in the corresponding chute 121, thereby driving the connected lower die slider 3 to move.

[0031] Furthermore, refer to Figure 7 , the structure of the lower die slider 3 is similar to that of the upper die slider 2. The lower die slider 3 is composed of a lower die model 31, a second stress ring 32 and a second slider 33. Among them, a lower die cavity 34 is formed inside the lower die model 31, the second stress ring 32 is sleeved on the outer periphery of the lower die model 31, the second slider 33 is sleeved on the outer periphery of the second stress ring 32, and at least one second screw hole 331 is provided in the middle of each of the left and right side surfaces of the second slider 33. Refer to Figure 6 , the upper end of the L-shaped lower die guiding rod 6 is connected to the second screw hole 331.

[0032] As Figure 3As shown, the upper die slider 2 and the lower die slider 3 are used as a concave die structure, the upper die slider 2 has an upper mold cavity 24, the lower die slider 3 has a lower mold cavity 34, and the diameter d0 of the upper mold cavity 24 is smaller than the diameter d1 of the lower mold cavity 34. After satisfying this condition, the diameter of the upper mold cavity 24 and the diameter of the lower mold cavity 34 can be determined according to the size of the bar 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 the two together constitute a forming cavity for upsetting the blank 15.

[0033] <Punch 8> 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 in matching shapes, and the two cooperate to form a concave-convex die 8 structure for extruding the blank 15 .

[0034] like Figure 3 As shown, a main pressure cylinder 10 for driving the punch 8 is provided on the upper crossbeam 11 of the frame 1, and the telescopic rod of the main pressure cylinder 10 is directed downward. An upper slide 9 is fixedly connected to the lower end of the telescopic rod of the main pressure cylinder 10, and the upper slide is used to fix the punch 8, and the upper end of the punch 8 is fixedly connected to the lower end of the upper slide 9.

[0035] When the main pressure cylinder 10 starts working, its telescopic rod will extend or retract as needed. The extended telescopic rod will push the upper slide plate 9 downward, thereby driving the punch 8 to be accurately pressed into the upper mold cavity 24 to extrude the blank 15. On the contrary, when the telescopic rod retracts, it will pull the upper slide plate 9 upward, thereby driving the punch 8 to be pulled out of the upper mold cavity 24, completing a complete working cycle. This design not only ensures the stability and accuracy of the movement of the punch 8, but also greatly improves the working efficiency and forming quality of the mold.

[0036] <Ejector mechanism 14> like Figure 3 and Figure 4 As shown, the ejection mechanism 14 is arranged below the lower die slide 3, and includes a pad 141 and an ejection cylinder 142, wherein the ejection cylinder 142 is arranged on the lower cross beam 13, and the lower end of the pad 141 is connected to the telescopic rod of the ejection cylinder 142. When the ejection cylinder 142 is working, its telescopic rod drives the pad 141 downward or upward to press in or pull out the lower mold cavity 34. The ejection mechanism 14 can not only be used to eject the blank 15 in the cavity upward, but also can be used to cooperate with the punch 8 to extrude the blank 15 together to ensure that the blank 15 can obtain higher forming accuracy and better surface quality.

[0037] The main pressure oil cylinder 10 and the ejector oil cylinder 142 used in this application are both oil cylinders with a rated pressure greater than 3000 tons, ensuring that sufficient working pressure can be provided during the die operation to meet the high-strength and high-precision forming requirements. The rated pressures of the upper die lifting oil cylinder 5 and the lower die jacking oil cylinder 7 only need to meet the requirements for driving the corresponding sliders respectively.

[0038] The method of this invention for upsetting-extrusion repeated cyclic forming includes the following steps (refer to Figure 3 and Figure 10 ): The specific steps for upsetting the billet 15 in a single pass are as follows: S1. First, set the lower die slider 3 and the backing plate 141 on the lower crossbeam 13 of the frame 1, so that the backing plate 141 is located at the bottom of the lower die cavity 34; S2. The telescopic rod of the upper die lifting oil cylinder 5 extends, driving the upper die guide rod 4 to move downward to press the upper die slider 2 against the lower die slider 3 for die closing. At this time, the upper die cavity 24 and the lower die cavity 34 are in a communicating state. After the upper die slider 2 and the lower die slider 3 are closed, with a pressure of hundreds of tons, it ensures that the horizontal gap after die closing does not overflow materials during the upsetting extrusion process, and at the same time overcomes the risk of easy breakage of bolts in the traditional method.

[0039] S3. Place the billet 15 (a casting rod with a diameter smaller than the upper die cavity 24) into the cavities of the upper die slider 2 and the lower die slider 3; S4. The telescopic rod of the main pressure oil cylinder 10 extends to push the upper slide plate 9 downward, pressing the punch 8 into the upper die cavity 24, and then pressing the billet 15 in the upper die cavity 24 into the lower die cavity 34 for upsetting. After upsetting, as Figure 3 and Figure 10 shown, the relationship between the length L0 of the forged billet, the length L1 of the upper die cavity 24, the length L2 of the lower die cavity 34, and the height h of the backing plate 141 is L0 = L1 + L2 - h.

[0040] S5. Ejection after upsetting: The telescopic rod of the main pressure oil cylinder 10 retracts to drive the upper slide plate 9 upward, pulling out the punch 8 from the upper die cavity 24 and resetting it. Then, the telescopic rod of the upper die lifting oil cylinder 5 retracts to lift and reset the upper die slider 2; finally, the lower die jacking oil cylinder 7 drives the lower die guide rod 6 to press against the lower die slider 3, and the telescopic rod of the ejector oil cylinder 142 extends to push the backing plate 141 upward to eject the upset billet 15 (casting billet) from the lower die cavity 34.

[0041] The multi-slider design of the present invention can easily separate the upper and lower die sliders 3. Meanwhile, with the assistance of the ejection mechanism 14, the upset blank 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 can also solve the unfavorable phenomenon of sticking mold during demolding. For example, by using the pressure of the main pressure oil cylinder 10 to make the punch 8 hold the head of the blank 15 and combining with the up and down movement of the upper die slider 2, the adhesion of the blank 15 in the upper die cavity 24 is effectively avoided, ensuring that the blank 15 can move up and down freely, and solving the demolding problem of the thin cast rod after upset extrusion.

[0042] In addition, the mold of the present invention is simple, can perform repeated upset extrusion with a large length-diameter ratio L0 / d0>10, and has reliable strength, can withstand large-tonnage extrusion operations, and has a long mold life.

[0043] The method of the present invention can also realize multi-cycle upsetting of the blank 15, and the specific steps are as follows (refer to Figure 11 ) S1. First, set the lower die slider 3 and the backing plate 141 on the lower cross beam 13 of the frame 1, so that the backing plate 141 is located at the bottom of the lower die cavity 34; S2. The telescopic rod of the upper die lifting oil cylinder 5 extends, driving the upper die guide rod 4 to descend and pressing the upper die slider 2 against the lower die slider 3 for mold closing. At this time, the upper die cavity 24 and the lower die cavity 34 are in a connected state; S3. Place the blank 15 (a cast rod with a diameter smaller than the upper die cavity 24) into the cavities of the upper die slider 2 and the lower die slider 3; S4. The telescopic rod of the main pressure oil cylinder 10 extends to push the upper slide plate 9 downward, pressing the punch 8 into the upper die cavity 24, and then pressing the blank 15 in the upper die cavity 24 into the lower die cavity 34 for primary upsetting; S5. The lower die lifting oil cylinder 7 drives the lower die guide rod 6 to press the lower die slider 3, and the telescopic rod of the ejection oil cylinder 142 extends to push the backing plate 141 upward, ejecting the upset blank 15 from the lower die cavity 34 into the upper die cavity 24, making the upset blank 15 become a thin blank 15 again, refer to Figure 11 , and then the ejection oil cylinder 142 retracts to drive the backing plate 141 to descend and reset; S6. Cycle 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.

[0044] In the existing traditional methods, if further extrusion deformation is to be performed on the upset blank 15 to refine its microstructure, the operator must first disassemble the upper guide cylinder and the lower guide cylinder, then flip the workpiece and re-fix it. In addition, a spacer ring needs to be added below the guide cylinder to raise the position of the blank 15 so that the punch 8 can move downward and compact on the backing plate 141, thereby completing the extrusion process of the blank 15 from thick to thin. This series of operation steps is not only complex and cumbersome, but also the entire processing flow is relatively long, resulting in low production efficiency. More critically, due to multiple loading, unloading and flipping, the temperature of the blank 15 will drop rapidly, which is particularly unfavorable for light alloy materials with high thermal sensitivity. Therefore, it is very difficult for the traditional multi-pass processing method to smoothly complete the entire deformation process from upsetting to extrusion in one heating (one heat). In contrast, the method of the present invention not only greatly simplifies the operation process, improves production efficiency, but also effectively maintains the temperature of the blank 15, providing the possibility for realizing repeated upsetting and extrusion preparation of difficult-to-process materials such as light alloys in one heating.

[0045] As Figure 12 shown, where (a) and (b) are the grain microstructure diagrams when upsetting the blank by the method of the present invention. It can be seen from the figure that the refined grains and precipitated phases are not large; while (c) and (d) are the grain microstructure diagrams when upsetting the blank by the traditional method. It can be seen from the figure that the grains are large and the precipitated phases at the grain boundaries are thick; Figure 13 is the stress-strain curve of the magnesium alloy blank in the tensile test. Among them, curve A represents the method of the present invention, and curve B represents the traditional method. It can be seen from the figure that for curve A, the tensile strength is 320 MPa and the elongation is 14%; for curve B, the tensile strength is 260 MPa and the elongation is 8%. The method of the present invention shows higher strength and plasticity in blank preparation and has better mechanical properties compared to the traditional method represented by curve B.

[0046] To further illustrate the embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used to explain the operating principle of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0047] At the same time, the front, rear, left, right and other orientations involved in this embodiment are only for reference of an orientation and do not represent the orientation in actual use. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0048] The above are only the preferred embodiments of the present invention, and do not limit the design of this case. All equivalent changes made according to the key design of this case fall within the protection scope of this case.

Claims

1. A method for upsetting-extrusion repeated cyclic forming, characterized in that: The method relates to a device for upsetting-extrusion repeated cycle forming. The device includes a frame, on which an upper die slider, a lower die slider, a punch and an ejection mechanism are provided; The side of the upper die slider is connected to the output end of the upper die lifting oil cylinder through an upper die guide rod and is driven by the upper die lifting oil cylinder to slide up and down; The side of the lower die slider is connected to the output end of the lower die jacking oil cylinder through a lower die guide rod and is driven by the lower die jacking oil cylinder to slide up and down; The upper die slider has an upper die cavity, and the lower die slider has a lower die cavity, and the diameter of the upper die cavity is smaller than that of the lower die cavity. When the upper die cavity and the lower die cavity are communicated, the two together form a forming cavity for upsetting the blank; The punch is located above the upper die slider, and the punch is driven by the main pressure oil cylinder to move down or up to press into or pull out of the upper die cavity; The ejection mechanism includes a backing plate and an ejection oil cylinder. The backing plate is located below the lower die slider, and the backing plate is driven by the ejection oil cylinder to move up or down to enter or exit the lower die cavity; The method includes the following steps: S1. Place the backing plate at the bottom of the lower die cavity of the lower die slider; S2. The telescopic rod of the upper die lifting oil cylinder extends, driving the upper die guide rod to move down to press the upper die slider against the lower die slider, so that the upper die cavity and the lower die cavity are communicated; S3. Place the blank into the cavities of the upper die slider and the lower die slider; S4. The telescopic rod of the main pressure oil cylinder extends to push the punch down, press the punch into the upper die cavity, and then press the blank in the upper die cavity into the lower die cavity for upsetting; S5. After a single upsetting is completed, the telescopic rod of the main pressure oil cylinder retracts to drive the punch to move up, pull the punch out of the upper die cavity and reset it, and then the telescopic rod of the upper die lifting oil cylinder retracts to lift and reset the upper die slider; Finally, the lower die jacking oil cylinder drives the lower die guide rod to press the lower die slider, and the telescopic rod of the ejection oil cylinder extends to push the backing plate up to eject the upset blank from the lower die cavity.

2. The method for upsetting-extrusion repeated cycle forming according to claim 1, characterized in that: The method can also realize multiple cycle upsetting of the blank, and the specific steps are as follows: S1. Place the backing plate at the bottom of the lower die cavity of the lower die slider; S2. The telescopic rod of the upper die lifting oil cylinder extends, driving the upper die guide rod to move down to press the upper die slider against the lower die slider, so that the upper die cavity and the lower die cavity are communicated; S3. Place the blank into the cavities of the upper die slider and the lower die slider; S4. The telescopic rod of the main pressure oil cylinder extends to push the punch down, press the punch into the upper die cavity, and then press the blank in the upper die cavity into the lower die cavity for upsetting; S5. The lower die jacking oil cylinder drives the lower die guide rod to press the lower die slider, and the telescopic rod of the ejection oil cylinder extends to push the backing plate up to eject the upset blank from the lower die cavity into the upper die cavity, so that the upset blank becomes a thin blank again, and then the ejection oil cylinder retracts to drive the backing plate to descend and reset; S6. Repeat S4 and S5 multiple times until the structure and properties of the blank meet the requirements and then stop working.

3. The method for upsetting-extrusion repeated cyclic forming according to claim 1, characterized in that: Vertical extending chutes are provided on both sides of the frame; One end of the upper die guide rod is connected to the end of the telescopic rod of the upper die lifting oil cylinder, and the other end vertically passes through the chute and is connected to the upper die slider; One end of the lower die guide rod is connected to the end of the telescopic rod of the lower die lifting oil cylinder, and the other end vertically passes through the sliding groove and is connected to the lower die slider; When the upper die lifting oil cylinder and the lower die lifting oil cylinder work, the guide rod moves in the corresponding sliding groove, and at the same time drives the connected slider to move.

4. The method for upsetting-extrusion repeated cyclic forming according to claim 1, characterized in that: The frame is a rectangular frame structure composed of an upper cross beam, two vertical plates and a lower cross beam.

5. The method for upsetting-extrusion repeated cyclic forming according to claim 4, characterized in that: The main pressure oil cylinder is arranged on the upper cross beam. The telescopic rod of the main pressure oil cylinder is connected to an upper sliding plate, and the upper end of the punch is connected to the lower end of the upper sliding plate; The ejection mechanism is arranged on the lower cross beam. The ejection oil cylinder in the ejection mechanism is arranged on the lower cross beam. The telescopic rod of the ejection oil cylinder faces the lower die cavity, and the lower end of the backing plate is connected to the telescopic rod of the ejection oil cylinder.

6. The method for upsetting-extrusion repeated cyclic forming according to claim 1, characterized in that: The upper die slider is composed of an upper die model, a first stress ring and a first slider. Among them, an upper die cavity is formed in the upper die model. The first stress ring is sleeved on the outer periphery of the upper die model. The first slider is sleeved on the outer periphery of the first stress ring. First screw holes for connecting with the upper die guide rod are arranged in the middle of both side faces of the first slider.

7. The method for upsetting-extrusion repeated cyclic forming according to claim 1, characterized in that: The lower die slider is composed of a lower die model, a second stress ring and a second slider. Among them, a lower die cavity is formed in the lower die model. The second stress ring is sleeved on the outer periphery of the lower die model. The second slider is sleeved on the outer periphery of the second stress ring. Second screw holes for connecting with the lower die guide rod are arranged in the middle of both side faces of the second slider.

8. The method for upsetting-extrusion repeated cyclic forming according to claim 1, characterized in that: Both the main pressure oil cylinder and the ejection oil cylinder adopt oil cylinders with a rated pressure greater than 3000 tons.

9. The method for upsetting-extrusion repeated cyclic 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 two sets of left and right driving mechanisms are symmetrically arranged on the frame.

10. An apparatus for the upsetting-extrusion repeated cyclic forming, which is used for the forming method according to any one of claims 1 to 9, characterized in that: It includes a frame, on which an upper die slider, a lower die slider, a punch and an ejection mechanism are arranged; The side of the upper die slider is connected to the output end of the upper die lifting oil cylinder through an upper die guide rod and is driven by the upper die lifting oil cylinder to slide up and down; The side of the lower die slider is connected to the output end of the lower die lifting oil cylinder through a lower die guide rod and is driven by the lower die lifting oil cylinder to slide up and down; The upper die slider has an upper die cavity, and the lower die slider has a lower die cavity. The diameter of the upper die cavity is smaller than that of the lower die cavity. When the upper die cavity and the lower die cavity are conducted, the two together form a forming cavity for upsetting the blank; The punch is located above the upper die slider. The punch is driven by the main pressure oil cylinder to move down or up to press into or pull out of the upper die cavity; The ejection mechanism includes a backing plate and an ejection oil cylinder. The backing plate is located below the lower die slider. The backing plate is driven by the ejection oil cylinder to move up or down to enter and exit the lower die cavity.

Images