Continuous reciprocating extrusion equipment and extrusion deformation method

Abstract

The invention provides continuous reciprocating extrusion equipment and an extrusion deformation method, and belongs to the field of metal material plastic deformation. The device comprises an upper ejector rod, an upper hydraulic cylinder, a lower ejector rod, a lower hydraulic cylinder, an hourglass-shaped cavity extrusion container, a hydraulic control system and the like. According to the device, equal reverse pressure is applied through an upper hydraulic cylinder and a lower hydraulic cylinder, a cylindrical metal blank 8 is fixed in an hourglass-shaped cavity of an extrusion barrel, and then the blank is driven to complete one-way extrusion in the extrusion cavity by utilizing the same-direction and same-speed displacement of the two hydraulic cylinders. And after the set displacement limit is reached, the two hydraulic cylinders simultaneously move in opposite directions and continue to keep the same direction and the same speed. And the synchronous reciprocating motion of the double hydraulic cylinders forces the blank (8) to realize reciprocating extrusion with the same frequency in the extrusion cavity. The reciprocating extrusion speed of the device is continuously adjustable, and the process requirements of different metal materials can be met. And through multiple times of reciprocating extrusion, the metal blank can accumulate large deformation, and grain refinement is achieved. Therefore, the device is also one of feasible technologies for obtaining metal fine grains.

Description

TECHNICAL FIELD

[0001] The present application relates to a continuous reciprocating extrusion device and an extrusion deformation method, and belongs to the field of plastic deformation of metal materials. BACKGROUND

[0002] Large strain is the common development direction of plastic deformation technology. Traditional rolling evolves into accumulative rolling (ARB), forging evolves into multi-directional forging (MF), extrusion evolves into high ratio extrusion (HRE) and equal channel angular extrusion (ECAE / ECAP), reciprocating extrusion (RE / CEC), and torsional deformation evolves into high pressure torsion (HPT). The above technologies are collectively referred to as severe plastic deformation (SPD), which can refine the grain to sub-micron or even nanometer level, and is recognized as the most feasible route to prepare bulk nanomaterials.

[0003] In 2000, Lu Wenlin et al. first proposed "sandglass extrusion" (SE) for the first time, which uses a sandglass-shaped cavity to reciprocally extrude Zn-Al alloy, realizes severe plastic deformation and induces dynamic recrystallization, and obtains equiaxed ultra-fine grain structure (Hot Working Technology, 2001, No. 2; Journal of Plastic Engineering, 2000, Vol. 7, No. 4). This process combines extrusion and upsetting in a necked cavity, which can significantly refine the grains and improve the mechanical properties. SUMMARY

[0004] Based on the theoretical basis of the above-mentioned sandglass-shaped cavity, a special hydraulic device is designed for realizing reciprocating extrusion based on the sandglass-shaped cavity. The main feature of the device is that it can implement extrusion pre-tightening force, and the pre-tightening force does not relax during the reciprocating extrusion process, so that the extrusion billet is always in a high-strength three-dimensional compressive stress state, thereby effectively inhibiting the generation and expansion of cracks. This feature is extremely beneficial to the billet-making process of brittle and difficult-to-deform metal materials (such as titanium-aluminum intermetallic compound materials, high-entropy alloys, etc.). At present, high-temperature canned extrusion is the conventional billet-making scheme for these difficult-to-deform metal materials. The canned extrusion has the following disadvantages: first, it increases the process cycle and cost; second, the one-way elongation deformation process greatly limits the total deformation amount of plastic processing; and third, conventional extrusion is not in a three-dimensional compressive stress state, and mainly relies on the pinching force of the outer sleeve to inhibit the generation of cracks, which is significantly lower than the high-strength compressive stress provided by the hydraulic system. Inhibition of cracking and single-fire large deformation is the deformation technology direction of the present application for emerging brittle materials.

[0005] Most high-end titanium alloy forgings (including ordinary hot die forging, isothermal forging, extrusion forming, etc.), the billet needs to be repeated upsetting for multiple heating. It is a kind of high energy consumption, difficult to automate and low efficiency process. The main problems include: repeated heating waste energy, surface crack needs to be ground, manual turnover and frequent transportation, etc. The reciprocating extrusion deformation described in the application has an equivalent true strain of ε≈4 in a single heating, which has the potential to replace repeated upsetting. Once replaced successfully, the reciprocating extrusion billet technology will become a high-efficiency, low-energy and easy-to-automate industrialized plastic processing development direction. If 1-2 heating reciprocating extrusion can replace repeated upsetting for more than ten times, the cycle will be shortened and the cost will be reduced, which will be a gain of orders of magnitude. Of course, this replacement process needs to be fully explored and verified by using a small tonnage prototype machine, and data for engineering difficulties such as large equipment tonnage, mold life extension, temperature rise control, etc. are accumulated, and the solution direction is provided.

[0006] The purpose of the application is achieved by the following technical scheme: a continuous reciprocating extrusion equipment, which comprises an upper hydraulic cylinder 5, an upper ejector rod 6, a lower hydraulic cylinder 10, a lower ejector rod 9, a sandglass-shaped cavity extrusion cylinder 7 and a force bearing member 3; the force bearing member 3 is used to ensure that the extrusion cylinder 7 can be reliably fixed on the equipment frame; during the reciprocating extrusion process, no expected displacement occurs between the extrusion cylinder 7 and the equipment frame; the upper ejector rod 6 is driven by the upper hydraulic cylinder 5 and can move up and down, and the lower ejector rod 9 is driven by the lower hydraulic cylinder 10 and can move up and down; the metal billet 8 is loaded into the sandglass-shaped cavity extrusion cylinder 7, and the upper and lower hydraulic cylinders simultaneously apply equal pressure to tightly extrude the metal billet 8 in the cavity of the sandglass-shaped cavity extrusion cylinder 7; after ensuring pre-tightening, the upper ejector rod 6 and the lower ejector rod 9 move synchronously, and the synchronous reciprocating movement of the upper ejector rod 6 and the lower ejector rod 9 forces the metal billet 8 in the sandglass-shaped cavity extrusion cylinder 7 to also realize reciprocating movement at the same frequency and repeatedly pass through the necking part in the middle of the sandglass-shaped cavity extrusion cylinder 7, thereby realizing reciprocating extrusion.

[0007] The equipment frame comprises an upper cross beam 1, a lower cross beam 4 and a column 2; all are force bearing structural members, and their structures and layouts adopt the design scheme of the general hydraulic equipment in the industry.

[0008] The upper ejector rod 6 and the lower ejector rod 9 have the same diameter and the same material.

[0009] The upper hydraulic cylinder 5 and the lower hydraulic cylinder 10 adopt coaxial layout and equal cross section design.

[0010] The synchronous movement required by the upper ejector rod 6 and the lower ejector rod 9 depends on the synchronous driving of the upper hydraulic cylinder 5 and the lower hydraulic cylinder 10; and the upper and lower hydraulic cylinders realize synchronous movement through a set of hydraulic control system.

[0011] The hydraulic control system comprises a plunger type liquid booster 20 and a set of pneumatic plunger pressure stabilizing system 24; the hydraulic control system further comprises a plurality of hydraulic valves (11, 12, 13, 14, 15, 18, 19, 21, 22, 23).

[0012] The extrusion deformation method of the continuous reciprocating extrusion device is as follows: when the two hydraulic valves 12 and 19 are in the closed state, the hydraulic main pump 17 is opened, and the remaining valves 11, 13, 14, 15, 18, 21, 22, and 23 are in the opened state. Under the action of the hydraulic main pump, the two hydraulic cylinders 5 and 10, as well as the hydraulic pipeline, the plunger type liquid booster, and the pneumatic plunger pressure stabilizing system all enter the pressure charging / liquid charging state; when the extrusion pre-tightening force generated by the two hydraulic cylinders reaches the process set value, the pre-tightening process ends.

[0013] When the valve 23 is closed and the valve 22 is opened, the pneumatic plunger pressure stabilizing system 24 implements individual pressure stabilization on the lower hydraulic cylinder; the valves 11 and 21 are in the opened state, and the valves 18 and 13 are in the closed state; the plunger type liquid booster 20 starts to operate, and the hydraulic medium flows from the lower hydraulic cylinder into the upper hydraulic cylinder under the action of the booster.

[0014] When the valve 23 is opened and the valve 22 is closed, the pneumatic plunger pressure stabilizing system 24 implements individual pressure stabilization on the upper hydraulic cylinder; the valves 11 and 21 are in the closed state, and the valves 18 and 13 are in the opened state; after the valve state is switched, the flow path of the hydraulic medium is reversed, and the hydraulic medium flows from the upper hydraulic cylinder into the plunger type liquid booster 20 and then into the lower hydraulic cylinder. 8. The reciprocating extrusion device further comprises an extrusion filler, which is loaded into the hourglass-shaped cavity of the extrusion cylinder 7 together with the metal blank 8; the loading sequence is as follows: the first portion of the filler, the heated metal blank, and the second portion of the filler are loaded into the cavity from the upper port in sequence; the first and second portions of the extrusion filler have equal amounts, and each portion is exactly capable of filling the necking region of the extrusion cavity to the brim.

[0015] The filler takes spherical or near-spherical granular material of ceramic or heat-resistant metal as the skeleton component, the particle diameter is 1.5-5.0 mm, and the volume fraction is controlled to be 35%-75%; in addition to the skeleton component, other auxiliary components are also needed, including one or more of void fillers, high-temperature binders, and surface tension agents.

[0016] The extrusion filler is composed of the following components with the following volume fractions:

[0017] a 2.0-2.5 mm zirconia spherical particles 40-60% as the skeleton;

[0018] b glass powder with a softening point of 500-600°C 10-20%;

[0019] c 600℃ liquid phase feldspar powder 5-15%;

[0020] d water glass 3-8% for cold pre-solidification;

[0021] The filling material shows Bingham fluid behavior under the co-extrusion condition of 500-700℃ and three-way compressive stress absolute value ≥120MPa, the yield stress is 80-110MPa, the apparent viscosity is 3×103-2×104Pa·s, the shear rate is 10s-1, and the co-extrusion interface with the metal blank does not penetrate each other. The technical scheme of the present application has the advantages of:

[0022] 1. During the whole reciprocating extrusion process, the extrusion blank 8 is subjected to stable three-way compressive stress, which can effectively inhibit the generation and expansion of cracks in the plastic deformation process. At the same time, in the whole compressive stress plastic flow process, the inherent defects in the metal blank, including micro-cracks, micro-shrinkage holes, porosity, etc. can be significantly eliminated. This feature provides more deformation scheme options for emerging materials such as brittle materials and high-entropy alloys, and is expected to replace the current canning extrusion process.

[0023] 2. For conventional extrusion or forging, the temperature selection needs to consider both yield stress and plasticity index. Only when both indexes reach the usable state can the deformation be easy and cracking be avoided. The fully three-way compressive stress extrusion realized by the present application can significantly reduce the demand for plasticity index of the blank. Because the crack suppression of the extrusion process completely depends on the three-way compressive stress, even if the plasticity material is 0, it will not crack during the extrusion flow process. Based on this characteristic, as long as the yield strength of the blank can meet the extrusion process, there is no need to consider its plasticity index too much. Obviously, the present application widens the processing temperature window of the material. For example, using the device, it is possible to realize large deformation extrusion of Ti-48Al-2Cr-2Nb (4822 alloy) below 1000℃.

[0024] 3. Reciprocating extrusion can realize large plastic deformation (SPD) of metal materials in single heating process, which can effectively refine the grain, and even obtain nanocrystalline structure. In addition, this single heating large deformation technology can replace the current general repeated upsetting and drawing process, so that the titanium alloy forging blanking process tends to be low energy consumption, short process and highly automated.

[0025] 4. The reciprocating extrusion device has simple, compact and efficient design, and has the potential of engineering and large-scale. Especially based on the double-cylinder synchronous driving technology of the liquid booster 20, almost all the energy consumption is used for material deformation work, which is significantly better than the energy efficiency of the current fast forging machine equipment. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Schematic diagram of the principle configuration of the double-hydraulic-cylinder reciprocating extrusion device;

[0027] Figure 2 Schematic diagram of synchronization control of double hydraulic cylinders

[0028] Figure 3 State curve diagram of hydraulic system (one cycle period)

[0029] Figure 4 Equipment configuration diagram suitable for 45*150 extrusion blank (WFJY-45-150)

[0030] Figure 5 Equipment configuration diagram suitable for large-size extrusion blank.

[0031] Wherein: 1 - upper cross beam, 2 - column, 3 - force member, 4 - lower cross beam, 5 - upper hydraulic cylinder, 6 - upper ejector rod, 7 - extrusion cylinder, 8 - metal blank, 9 - lower ejector rod, lower hydraulic cylinder 10, 16 - mailbox, 17 - hydraulic main pump, 20 - liquid booster, 11-15 and 18-23 - valve, 24 - pneumatic plunger pressure stabilizing system, 101 - upper hydraulic cylinder clamping beam, 201 - main pull rod, 202 - column sleeve, 203 - main pull rod nut, 301 - extrusion cylinder upper clamping beam, 302 extrusion cylinder lower clamping beam, 303 - lower pull rod, 304 - lower sleeve, 305 - upper pull rod, 306 - upper sleeve, 308 - extrusion cylinder upper support, 309 - moving track, 401 - lower hydraulic cylinder clamping beam, 501 - piston a, 502 - oil cylinder sleeve a, 701 - upper flange, 702 - lower flange, 1001 - piston b, 1002 - oil cylinder sleeve b DETAILED DESCRIPTION

[0032] The technical scheme of the present application will be further described in detail below in combination with the drawings and examples:

[0033] A continuous reciprocating extrusion equipment,

[0034] The continuous reciprocating extrusion device based on the hourglass-shaped cavity can adopt a traditional hydraulic equipment configuration, which can refer to a four-column hydraulic press, a vertical extrusion machine, a horizontal extrusion machine, etc. The device has the following characteristics: an equal loading scheme with a coaxial layout of double hydraulic cylinders is adopted, the device includes an upper ejector rod and an upper hydraulic cylinder, a lower ejector rod and a lower hydraulic cylinder, an hourglass-shaped cavity extrusion cylinder, a hydraulic control system, etc. The device applies equal and opposite pressure through the upper and lower hydraulic cylinders to fix the cylindrical metal blank 8 inside the hourglass-shaped cavity of the extrusion cylinder, and then drives the blank to complete reciprocating extrusion in the extrusion cavity by the same direction and speed displacement of the two hydraulic cylinders. The present application proposes a double hydraulic cylinder synchronization driving scheme, which has three characteristics: low energy consumption, high stability, and simple hardware principle.

[0035] The device comprises an upper hydraulic cylinder 5, an upper ejector rod 6, a lower hydraulic cylinder 10, a lower ejector rod 9, a sandglass-shaped cavity extrusion cylinder 7, and a force-bearing component 3; the force-bearing component 3 is used to ensure that the extrusion cylinder 7 can be reliably fixed on the equipment frame; during the reciprocating extrusion process, no displacement is expected to occur between the extrusion cylinder 7 and the equipment frame; the upper ejector rod 6 is driven by the upper hydraulic cylinder 5 and can perform up-and-down movement, and the lower ejector rod 9 is driven by the lower hydraulic cylinder 10 and can perform up-and-down movement; the metal blank 8 is loaded into the sandglass-shaped cavity extrusion cylinder 7, and the upper and lower hydraulic cylinders simultaneously apply equal pressure to tightly extrude the metal blank 8 in the cavity of the sandglass-shaped cavity extrusion cylinder 7; after ensuring pre-tightening, the upper ejector rod 6 and the lower ejector rod 9 perform synchronous movement, and the synchronous reciprocating movement of the upper ejector rod 6 and the lower ejector rod 9 forces the metal blank 8 in the sandglass-shaped cavity extrusion cylinder 7 to also realize reciprocating movement at the same frequency and repeatedly pass through the necking part in the middle of the sandglass-shaped cavity extrusion cylinder 7, thereby realizing reciprocating extrusion.

[0036] The equipment frame comprises an upper cross beam 1, a lower cross beam 4, and a stand column 2; all are force-bearing structural components, and their structures and layouts adopt the design scheme of the general hydraulic equipment in the industry.

[0037] The upper ejector rod 6 and the lower ejector rod 9 have the same diameter and the same material.

[0038] The upper hydraulic cylinder 5 and the lower hydraulic cylinder 10 adopt coaxial layout and equal-section design.

[0039] The synchronous movement required by the upper ejector rod 6 and the lower ejector rod 9 depends on the synchronous driving of the upper hydraulic cylinder 5 and the lower hydraulic cylinder 10; and the upper and lower hydraulic cylinders realize synchronous movement through a set of hydraulic control systems.

[0040] The hydraulic control system comprises a plunger type liquid booster 20 and a pneumatic plunger pressure stabilizing system 24; the hydraulic control system further comprises multiple valves 11, 12, 13, 14, 15, 18, 19, 21, 22, and 23, which are used to switch the flow path of the hydraulic medium, and the valves only have on-off function and do not need flow control function.

[0041] The extrusion deformation method of the continuous reciprocating extrusion device is as follows: when two liquid return valves 12 and 19 are in a closed state, a hydraulic main pump 17 is opened, and the remaining valves 11, 13, 14, 15, 18, 21, 22, and 23 are in an open state. Under the action of the hydraulic main pump, the two hydraulic cylinders 5 and 10, as well as the hydraulic pipeline, the plunger type liquid booster, and the pneumatic plunger pressure stabilizing system all enter the pressure charging / liquid charging state; when the extrusion pre-tightening force generated by the two hydraulic cylinders reaches the process set value, the pre-tightening process ends.

[0042] The system can realize synchronous driving of the two hydraulic cylinders in pre-tightening state, and no pressure relaxation occurs during driving. The realization steps of synchronous downward movement are as follows: when the valve 23 is closed and the valve 22 is opened, the pneumatic plunger pressure stabilizing system 24 implements independent pressure stabilization on the lower hydraulic cylinder; the valves 11 and 21 are opened, and the valves 18 and 13 are closed; the plunger type liquid booster 20 starts to operate, and the hydraulic medium flows into the upper hydraulic cylinder under the action of the booster; during the medium transfer, the pneumatic plunger pressure stabilizing system 24 can effectively ensure that the lower hydraulic cylinder does not relax. The plunger type liquid booster 20 ensures that the medium volume lost by the lower hydraulic cylinder and the medium volume increased by the upper hydraulic cylinder are completely equal, and based on the equal cross section design of the two hydraulic cylinders, the displacement sizes of the two hydraulic cylinders are also necessarily equal.

[0043] During the synchronous downward movement of the two hydraulic cylinders, the flow of the plunger type liquid booster 20 is the only controllable quantity; the flow control is used to match the extrusion speed required by the process, and does not significantly interfere with the autonomous stability of the system.

[0044] During the synchronous downward movement of the two hydraulic cylinders, there is a dynamic pressure difference between the liquid media in the upper and lower hydraulic cylinders, and the pressure difference is derived from the driving force of the plunger type liquid booster 20. However, the actual size of the pressure difference does not depend on the outlet pressure of the booster, but depends on the extrusion resistance in the extrusion barrel, which includes the rheological resistance and sliding friction.

[0045] Only by switching the valve state, the synchronous downward driving of claim 1 can be converted into synchronous upward driving. The switching mode is as follows: when the valve 23 is opened and the valve 22 is closed, the pneumatic plunger pressure stabilizing system 24 implements independent pressure stabilization on the upper hydraulic cylinder; the valves 11 and 21 are closed, and the valves 18 and 13 are opened; after the valve state is switched, the flow direction path of the hydraulic medium is reversed, and the hydraulic medium flows into the plunger type liquid booster 20 from the upper hydraulic cylinder, and then flows into the lower hydraulic cylinder. 8, the reciprocating extrusion device further comprises an extrusion filler, the extrusion filler is loaded into the hourglass-shaped cavity of the extrusion barrel 7 together with the metal blank 8; the loading sequence is to load the first portion of the filler, the heated metal blank and the second portion of the filler into the cavity from the upper end port in sequence; the first portion and the second portion of the extrusion filler are equal in amount, and when converted into compacted volume, each portion can exactly fill the necking region of the extrusion cavity.

[0046] The filler must meet the following physical properties: firstly, it has good rheological ability and can conform to the shape of the rigid constraint of the extrusion cavity. Secondly, it can ensure the stability of the co-extrusion interface between the filler and the metal blank during the extrusion process under three-way pressure stress, and cannot penetrate between the filler and the blank. Thirdly, it cannot penetrate into the extrusion lubricant. The above three properties are the high-temperature working properties of the filler, and the applicable temperature range is 400-800°C. Fourthly, at room temperature, the filler can be self-dispersed, or it is brittle and has very low strength, and can be quickly broken by manual simple beating.

[0047] The filler is a spherical or near-spherical particle of ceramic or heat-resistant metal as a skeleton component, with a particle diameter of 1.5-5.0 mm and a volume fraction controlled at 35%-75%. In addition to the skeleton component, other auxiliary components are also needed, including three types of void fillers, high-temperature binders, and surface tension agents.

[0048] The extrusion filler is composed of the following components by volume fraction:

[0049] a 2.0-2.5 mm zirconia spherical particles 40-60% as a skeleton;

[0050] b glass powder with a softening point of 500-600°C 10-20%;

[0051] c feldspar powder forming a liquid phase at 600°C 5-15%;

[0052] d water glass 3-8% for cold pre-solidification;

[0053] The filler exhibits Bingham fluid behavior under co-extrusion conditions of 500-700°C and three-way pressure stress absolute value ≥120 MPa, with a yield stress of 80-110 MPa, an apparent viscosity of 3×103-2×104 Pa·s, a shear rate of 10 s-1, and no mutual penetration of the co-extrusion interface with the metal blank. The above-described upper ram 6, lower ram 9, upper hydraulic cylinder 5, and lower hydraulic cylinder 10 are described for the sake of simplicity of the text. The device can be designed as a horizontal structure, and the corresponding orientation description is left ram, right ram, left hydraulic cylinder, and right hydraulic cylinder. Whether it is a vertical or horizontal structure, the principle and function of the device will not be affected.

[0054] Reciprocal extrusion is the exclusive use of the device, which can maintain a stable three-way pressure stress state throughout the extrusion process. The implementation process is as follows:

[0055] First, ensure that the device is coaxially aligned, with the upper and lower hydraulic cylinders, the upper and lower rams, and the cavity of the extrusion cylinder all on the same central axis. The alignment accuracy mainly depends on the machining accuracy of the parts and the assembly accuracy of the device.

[0056] In the state of equipment readiness, a charging process is involved.

[0057] The upper ram 9 is lifted to the inside of the extrusion cylinder 7 and is raised to approach its upper limit position.

[0058] Further, the first extrusion filler, the extrusion billet and the second extrusion filler are sequentially placed from above the extrusion cylinder; the components and weights of the two fillers should be exactly the same.

[0059] In the above charging process, since the lower ram has been inserted into the extrusion cavity, it has a lifting effect on the materials placed above, ensuring that the materials will not fall out of the cavity. The extrusion billet needs to be heated to the required temperature in advance by using a box-type resistance furnace.

[0060] After the charging process is completed, an extrusion pre-tightening process is involved.

[0061] The upper ram 6 is lowered to the inside of the extrusion cylinder 7, ensuring that the lower end surface of the ram is close to the upper surface of the extrusion filler.

[0062] Further, the upper oil cylinder is slowly loaded, forcing the upper ram to exert a pre-tightening force on the materials in the cavity. When the upper oil cylinder is loaded, the return valve of the lower oil cylinder must be closed, forcing the medium pressure of the lower oil cylinder to be passively raised. When the pre-tightening force reaches about 50% of the preset value, the loading of the upper oil cylinder is stopped, and the lower oil cylinder is used instead, until the pre-tightening pressure reaches 100% of the set value; generally speaking, the stress value generated in the billet by the pre-tightening force should be 1.2-2.0 times the yield strength of the material. During the pre-tightening process, although the billet is subjected to a load exceeding the yield strength, it will not undergo plastic flow because the billet is constrained inside a closed rigid cylinder. The pre-tightening loading is first applied to the upper ram and then to the lower ram, which has the advantage that the upper ram is far from its physical lower limit position, and the change in position from the relaxed state to the stressed state will not cause an over-limit situation. The lower ram is almost close to its physical upper limit position, and if it is loaded in the relaxed state, it is likely to cause over-limit damage.

[0063] Further, when the loading forces of the upper and lower oil cylinders reach the set value, the pre-tightening process is completed. Through pre-tightening loading, the extrusion billet is in a complete three-dimensional compressive stress state and maintains its shape unchanged. The extrusion cylinder also forms an elastic hoop shrinkage stress, which is approximately equal to the axial pre-tightening stress minus the yield strength of the billet. After the extrusion pre-tightening is completed, a downward extrusion process is involved.

[0064] First, the valve 23 is closed and the valve 22 is opened, ensuring that the pneumatic plunger pressure stabilizing system 24 applies a separate pressure stabilization to the lower hydraulic cylinder.

[0065] Further, the valves 11, 21 are open, and the valves 18, 13 are closed. The plunger liquid booster 20 is in operation, and the hydraulic medium flows from the lower hydraulic cylinder to the upper hydraulic cylinder under the action of the booster. During the medium transfer, the pneumatic plunger pressure stabilizing system 24 can effectively ensure that the lower hydraulic cylinder does not relax.

[0066] Further, the plunger liquid booster 20 can ensure that the medium volume lost by the lower hydraulic cylinder and the medium volume added by the upper hydraulic cylinder are completely equal, and the two hydraulic cylinders are of equal cross-section design, and under the action of the equal volume of medium, the displacements generated by the two hydraulic cylinders are also completely equal. Figure 3 The downward extrusion shown shows the time variation of important state parameters such as the thrust of the upper and lower hydraulic cylinders and the speed of the upper and lower jacks during the process.

[0067] The plunger liquid booster 20 is used to realize the equal volume medium transfer between the two hydraulic cylinders, which is one of the important features of the device. This design ensures the synchronous displacement of the double hydraulic cylinders from the physical nature. The lower cylinder body loses medium, which inevitably generates downward displacement, and the upper cylinder body adds equal volume medium, which also inevitably generates equal distance downward displacement. The process does not require other additional control means, and it is a physically self-consistent synchronous displacement process. Although the process realizes displacement synchronization, it inevitably causes pre-tightening force fluctuation, and even complete relaxation. The pneumatic plunger pressure stabilizing system 24 can well overcome the medium pressure disturbance and realize the whole process stability of the pre-tightening force.

[0068] The process details are as follows: in one pumping cycle of the liquid booster 20, first, △V of liquid medium is extracted from the lower oil cylinder. After extraction, the lower oil cylinder loses medium, which inevitably causes pressure relaxation, but since the lower oil cylinder is connected to the pressure stabilizing system 24 at this time, the pneumatic pressure stabilizing mechanism will respond instantaneously to stabilize the medium pressure to the preset state. The liquid booster 20 then injects △V of equal amount of liquid medium into the upper oil cylinder, and the upper oil cylinder generates downward displacement, which inevitably forces the lower oil cylinder to synchronously and equally downward, and this process also causes pressure disturbance of the lower oil cylinder. Again, the instantaneous response of the pressure stabilizing system 24 ensures that the medium pressure of the lower oil cylinder is stabilized at the preset state. The above physical details occur in the millisecond time range, and from the macro time scale, it is embodied as the synchronous downward of the upper and lower oil cylinders, and the pre-tightening pressure is always stable.

[0069] During the synchronous downward of the double hydraulic cylinders, the only control variable is the flow of the plunger liquid booster 20, which can be continuously controlled by the speed of the variable frequency motor. Controlling the flow does not significantly interfere with the self-stability of the system. The macro effect of controlling the flow is embodied as the fast or slow of the downward speed.

[0070] In the process of synchronous downward extrusion, there is a dynamic pressure difference between the upper and lower hydraulic cylinders, which is caused by the driving force of the plunger liquid booster 20. However, the actual size of the pressure difference does not depend on the outlet pressure of the booster, but on the extrusion resistance, which includes two parts: the resistance of the billet to the necking area of the extrusion cavity, and the sliding friction between the billet and the inner wall of the extrusion cavity. These two forces are collectively referred to as the extrusion resistance.

[0071] In this device, the extrusion resistance has certain controllability. The principle is that when the pre-tightening force is increased, the lateral pressure of the extrusion billet on the inner wall of the cavity will also increase, which will lead to an increase in friction. At the same time, for a metal plastic body, its yield stress will also increase under three-dimensional compressive stress, which will also increase the flow resistance of the billet through the necking area. The control range of the extrusion resistance and the resulting process effect need to be further explored through experiments.

[0072] The end of the downward extrusion process is determined by the stroke of the top rod. At this time, the position of the material and parts in the extrusion cavity is described as follows:

[0073] The lowermost end of the upper top rod is close to the necking area of the extrusion cavity, but it is not allowed to enter the necking position.

[0074] The second extrusion filler is tightly attached to the upper top rod and almost completely fills the necking area.

[0075] The metal extrusion billet 8 has passed through the necking area and entered the straight cylinder area below as a whole.

[0076] The first extrusion filler is tightly attached to the upper end surface of the lower top rod.

[0077] The uppermost end of the lower top rod is close to the lower end outlet position of the extrusion cavity.

[0078] After the downward extrusion is completed, an upward extrusion process is involved.

[0079] First, valve 23 is opened and valve 22 is closed to ensure that the pneumatic plunger pressure stabilizing system 24 applies pressure to the upper hydraulic cylinder alone.

[0080] Further, valves 11 and 21 are closed, and valves 18 and 13 are opened. The plunger liquid booster 20 starts to operate, and the hydraulic medium flows into the lower hydraulic cylinder under the action of the booster. During the medium transfer process, the pneumatic plunger pressure stabilizing system 24 can effectively ensure that the upper hydraulic cylinder does not relax.

[0081] Further, the plunger liquid booster 20 ensures that the volume of the medium lost by the upper hydraulic cylinder and the volume of the medium added to the lower hydraulic cylinder are completely equal, and the displacement generated by the two is also completely equal.

[0082] The more detailed control principle has been described in the downward extrusion process.

[0083] The end of the upward extrusion process is marked by the stroke of the top rod; at this time, the position of the material and the part in the extrusion cavity is described as follows:

[0084] The lower end of the top rod approaches the upper end of the extrusion cavity.

[0085] The second extrusion filler is close to the lower end surface of the top rod.

[0086] The metal extrusion billet has passed through the necking area and returned to the straight cylinder area above.

[0087] The first extrusion filler is close to the upper end surface of the lower top rod, almost all filled in the necking area.

[0088] The upper end surface of the lower top rod is basically close to the necking area of the extrusion cavity, but is not allowed to enter the necking position.

[0089] In fact, the position of the material and the part at this time has completely returned to the position after the extrusion pre-tightening. The downward extrusion and the upward extrusion constitute a complete reciprocating extrusion cycle.

[0090] In a complete extrusion cycle, the cylindrical metal billet passes through the necking area in the middle of the extrusion cylinder twice; the cross-sectional area of the necking area is about 50% of the original cross-sectional area of the rod, and the metal billet will undergo severe shear deformation in the necking area. This deformation is uniform in the radial direction and there is no significant deformation dead zone. After multiple reciprocations, the cumulative strain of the metal billet will reach a very high degree. This strong plastic distortion can probably create a new organizational state, such as nanometer ultra-fine grains, long whisker structure, etc.

[0091] According to the setting of the extrusion speed, each cycle is about 5-20 seconds; the number of cycles depends on the material properties and process requirements;

[0092] Example 1

[0093] Appendix Figure 4 is based on the Figure 1 A specific implementation is shown in the figure, named hourglass cavity reciprocating extrusion prototype machine, model WFJY-45-150.

[0094] The core function of WFJY-45-150 is to realize the reciprocating extrusion of φ45mmx150mm cylindrical metal billet, which weighs about 1kg according to the density of titanium alloy. As a research and exploration, it can cover most of the targets. Based on this core data, gradually expand the design outward, the key parameters of the equipment can be determined. The specific order is as follows:

[0095] 1. Important dimensions of extrusion container 7, upper and lower flanges 701, 702 of extrusion container

[0096] (a) Extrusion cavity diameter: 47 mm for straight section, 32 mm for necked section

[0097] (b) Extrusion cavity height: 196 mm for upper straight section, 196 mm for lower straight section, 60 mm for necked section; total height 452 mm; 60 mm height of necked section includes intermediate minimum diameter section and upper and lower transition sections

[0098] (c) Extrusion container body diameter: 310 mm; double sleeve structure is used, inner sleeve K403 cast high-temperature alloy, wall thickness 55 mm; outer sleeve 1Cr11MoV, wall thickness 75 mm

[0099] (d) Extrusion container flange size: φ 435 mm x 50 mm; after installation of upper and lower flanges, total height of extrusion container assembly is 552 mm

[0100] 2. Important dimensions of upper hydraulic cylinder 5

[0101] (a) Nominal cylinder bore diameter: 245 mm; maximum load tonnage 144 tons (medium pressure 30 MPa)

[0102] (b) Large diameter of piston a501: 245 mm; small diameter 225 mm, design return force 23 tons

[0103] (c) Maximum ejection stroke: 425 mm

[0104] (d) Cylinder load ring: height 180 mm, thickness 25 mm; welded or integrally machined with cylinder

[0105] 3. Important dimensions of lower hydraulic cylinder 10

[0106] (a) Nominal cylinder bore diameter: 245 mm; maximum load tonnage 144 tons (medium pressure 30 MPa)

[0107] (b) Large diameter of piston b1001: 245 mm; small diameter 225 mm, design return force 23 tons

[0108] (c) Maximum ejection stroke: 310 mm

[0109] (d) Cylinder load ring: height 180 mm, thickness 25 mm; welded or integrally machined with cylinder

[0110] 4. Cross beam components

[0111] (a) Upper cross beam 1, referred to as A beam, thickness 150 mm

[0112] (b) Lower cross beam 4, referred to as B beam, thickness 150mm

[0113] (c) Upper hydraulic cylinder clamping beam 101, referred to as C beam, thickness 50mm

[0114] (d) Lower hydraulic cylinder clamping beam 401, referred to as D beam, thickness 50mm

[0115] (e) Upper extrusion cylinder clamping beam 301, referred to as E beam, thickness 50mm

[0116] (f) Lower extrusion cylinder clamping beam 302, referred to as F beam, thickness 50mm

[0117] The above six beams (A, B, C, D, E, F) are all square plate-shaped components in the axial projection direction, with a side length of 600mm.

[0118] 5. Frame tie rods and support sleeves

[0119] (a) Main tie rods 201, a total of 4, 42CrMo quenching and tempering treatment, diameter 36mm, length about 2450mm

[0120] (b) Support sleeves 202, a total of 20, inner diameter 37mm, outer diameter 70; ZG340-640 cast steel; Among them, A-C beam support sleeves, height 180mm, a total of 4; C-E beam support sleeves, height 380mm, a total of 4; E-F beam support sleeves, height 780mm, a total of 4; F-D beam support sleeves, height 280mm, a total of 4; D-B beam support sleeves, height 180mm, a total of 4;

[0121] (c) Main tie rod nuts 203, a total of 8, 40CrMo quenching and tempering treatment, M36x3.5;

[0122] 6. Extrusion cylinder fixing tie rods and sleeves

[0123] (a) Upper tie rods 305: diameter 24mm, length 360mm; a total of 4;

[0124] (b) Upper sleeves 306: inner diameter 25mm, outer diameter 50mm, height 175mm; a total of 4;

[0125] (c) Lower tie rods 303: diameter 24mm, length 230mm; a total of 4;

[0126] (d) Lower sleeves 304: inner diameter 25mm, outer diameter 50mm, height 60mm; a total of 4;

[0127] The above tie rods are all 42CrMo quenching and tempering treatment; the above sleeves are all 45# carbon steel quenching and tempering treatment.

[0128] 7. Hydraulic control system

[0129] (a) Plunger type liquid booster 20: reference model GYB-90 / 2.0-VFD, Hefei General Machinery Research Institute;

[0130] • Drive mode: three-phase permanent magnet synchronous motor + vector frequency converter;

[0131] - Rated power 22 kW

[0132] - Rotational speed 0-2900 r / min continuously adjustable, corresponding flow rate 0-90 L / min

[0133] • Boosting performance

[0134] - Inlet pressure 5-25 MPa

[0135] - Fixed mechanical boosting ratio 1.8 (optional 2.0 head)

[0136] - Outlet pressure 9-45 MPa (linear relationship with inlet)

[0137] (b) Pneumatic plunger pressure stabilizing system 24: reference model MPV-D series pneumatic plunger pressure stabilizing system, Shandong Saiste MPV-D-40-2.5-PLC.

[0138] • Core components

[0139] - MPV-D-40 type double-acting pneumatic plunger cylinder (compression ratio 40:1)

[0140] Drive piston Plunger Only 0.75 MPa air source - 2.5 L piston accumulator (40 MPa certified)

[0141] - Electromagnetic directional valve + electromagnetic proportional pressure reducing valve (24 V DC)

[0142] • Working logic

[0143] Continuous double-acting reciprocation → plunger directly pressurizes oil into high-pressure accumulator;

[0144] PLC controls electromagnetic valve opening / closing according to pressure feedback, achieving ±3% pressure stabilization.

[0145] (c) Oil tank 16, hydraulic main pump 17, valves, hydraulic pipelines, etc., belong to the category of conventional hydraulic equipment, which can be selected according to industry standards.

[0146] The geometric dimensions of the above components are nominal dimensions to meet load strength, and do not include engineering deviations during component manufacturing. The reciprocating extrusion process performance of the device is as follows:

[0147] Maximum charge size: φ45mm x 150mm / 1kg (titanium alloy)

[0148] Maximum pre-tightening force: 144 tons (axial compressive stress of blank ≈ 850 MPa)

[0149] Process practical pre-tightening force: 15-100 tons (axial compressive stress of blank ≈ 88-590 MPa)

[0150] Reciprocating extrusion force: 1.8 times or 2.0 times the pre-tightening force

[0151] Reciprocating extrusion speed: 0.1mm / s-32mm / s, continuously adjustable.

[0152] The above extrusion speed is mainly determined by the flow parameter of the plunger type liquid booster (20), and 32mm / s corresponds to a flow of 90L / min.

[0153] The reciprocating extrusion device is an elongated hydraulic device with a length-diameter ratio ≥ 4.0. Therefore, the center of gravity of the device is relatively high, and for the safety of operation, a suitable steel structure support is needed to place it securely. It can also be considered to be placed horizontally, from vertical to horizontal. For the horizontal state, the principle of reciprocating extrusion does not change, but the operation difficulty of the charging process increases. In the process of horizontal reciprocating extrusion, the high-temperature lubricant will also be affected by gravity and eccentric flow, thereby affecting the sliding friction.

[0154] The operation process of the device described in the present application is as follows:

[0155] Step one, use the matched box-type resistance furnace to heat the extrusion blank, and ensure that the yield strength of the blank at the heating temperature is in the range of 50-300MPa, and the best range is 150-200MPa;

[0156] Step two, use the matched box-type resistance furnace to heat the extrusion cavity preheating material, extrusion filler and other process auxiliary materials. The heating temperature is usually not more than 600℃. The extrusion cavity preheating material can be fine industrial quartz sand. The extrusion filler is described in claims 7 and 8.

[0157] Step three, preheat the extrusion cavity. It is carried out 10-15 minutes before reciprocating extrusion, lift the lower top rod 9 to the lower end of the extrusion cylinder 7 and extend into 50mm; pour the heated quartz sand material from the upper end of the extrusion cylinder 7, and then lower the upper top rod 6 to the upper end of the extrusion cylinder and extend into about 50mm; The cavity preheating process does not need to load pressure, but only uses the upper and lower top rods to block the preheated sand material in the extrusion cavity.

[0158] Step four, clean up the preheated material. After preheating for 10-15 minutes, take out the quartz sand from the lower port of the extrusion cylinder 7. Note that the quartz sand can flow naturally, so before the lower ejector rod is separated from the lower port, a suitable metal tray must be prepared to quickly catch the flowing quartz sand material. Pay attention to the dangers of burns and sand splashing during the operation. Quickly clean up the scattered quartz sand to ensure that the lower cross beam 302 and the F beam are clean enough to prevent damage to the sliding parts such as the lower ejector rod.

[0159] Step five, loading. Raise the lower ejector rod until its net height into the extrusion chamber is approximately 243 mm. Load the first portion of the extrusion filler, the extrusion billet 8, and the second portion of the extrusion filler into the upper port of the extrusion cylinder in sequence.

[0160] Step six, extrusion pre-tightening. Lower the upper ejector rod until its net height into the extrusion chamber is approximately 50 mm. The upper ejector rod is loaded at a low speed, with a lowering speed ≤0.5 mm / s. When the medium pressure meets 45%-55% of the set pre-tightening force, the upper ejector rod stops. Then the lower ejector rod starts to load until the medium pressure meets the set pre-tightening force. The size of the pre-tightening force depends entirely on the characteristics of the billet and the process requirements. Generally, the extrusion pre-tightening force should reach more than 1.2 times the yield point of the billet to ensure that the billet enters a fully three-dimensional compression stress state and that sufficient elastic hoop stress is formed inside the extrusion cylinder.

[0161] Step seven, downward extrusion. The hydraulic control system is switched to the downward extrusion state, valve 23 is closed, valve 22 is opened, and the pneumatic plunger pressure stabilizing system 24 implements independent pressure stabilization for the lower hydraulic cylinder. Valves 11 and 21 are open, and valves 18 and 13 are closed. The plunger-type liquid booster 20 starts to operate, and the hydraulic medium flows from the lower hydraulic cylinder into the upper hydraulic cylinder under the action of the booster. During the medium transfer process, the pneumatic plunger pressure stabilizing system 24 can effectively ensure that the lower hydraulic cylinder does not relax. The synchronous displacement speed of the upper and lower ejector rods during the entire stroke of the downward extrusion should be controlled by PLC programming, which basically includes three stages of acceleration, constant speed, and deceleration. This process only needs to control the flow parameters of the liquid booster 20.

[0162] Step eight, upward extrusion. The hydraulic control system is automatically switched to the upward extrusion state, the hydraulic control system is switched to the downward extrusion state, valve 23 is opened, valve 22 is closed, and the pneumatic plunger pressure stabilizing system 24 implements independent pressure stabilization for the upper hydraulic cylinder. Valves 11 and 21 are closed, and valves 18 and 13 are opened, and the flow path of the hydraulic medium is reversed, flowing from the upper hydraulic cylinder into the lower hydraulic cylinder under the action of the booster 20. During the medium transfer process, the pneumatic plunger pressure stabilizing system 24 can effectively ensure that the upper hydraulic cylinder does not relax. The synchronous displacement speed of the upper and lower ejector rods during the entire stroke of the upward extrusion should also be controlled by PLC programming, which also includes three stages of acceleration, constant speed, and deceleration.

[0163] Step nine, reciprocating extrusion. The downward extrusion step seven and upward extrusion step eight are collectively called reciprocating extrusion, which allows unlimited execution in terms of physical principles. In engineering, it is limited by the temperature rise of the extrusion billet, the temperature rise of the extrusion cavity, the wear resistance of the extrusion cavity and other problems. Therefore, the actual number of reciprocating extrusions is generally 5-20 times. Figure 3 The interrelationship of downward extrusion, upward extrusion and reciprocating cycle is shown, and the variation law of important state parameters such as the speed of the top rod, the thrust of the hydraulic cylinder and the position of the billet in a cycle period is described in a broken line manner. Based on the broken line graph, the hydraulic drive principle of the device can be better understood.

[0164] Step ten, taking material. After the specified number of reciprocating extrusion cycles is executed, the state of the equipment and the material should be completely restored to the extrusion pre-tightening state; first, unload the extrusion pre-tightening force to ensure that the axial main load is completely relaxed to zero. Then lift the upper top rod 6 to the upper limit position to leave the space for taking out the material. The lower top rod 9 is lowered to the lower limit position to leave the space for inserting the top material. From the lower end of the extrusion cylinder, insert the ordinary graphite block, which is called the top material block, with a size of φ47.1mmx55mm, and a 45° chamfer is machined at both ends. With the assistance of the lower top rod, 2-3 top material blocks are inserted into the extrusion cavity from the lower end, and finally the lower top rod is lifted until the extrusion billet is exposed from the upper end. The billet is taken out manually with a fire tongs.

[0165] At this point, the whole process of reciprocating extrusion is completed.

[0166] Example 2

[0167] This example is used to realize the reciprocating extrusion of a φ30mmx100mm cylindrical metal billet, which weighs about 0.32kg according to the density of titanium alloy. The design configuration is completely consistent with the configuration of the device shown in the attached drawings. Figure 4

[0168] The total height of the assembled device is about 2040mm;

[0169] The nominal inside diameter of the upper and lower hydraulic cylinders is 170mm / 70 tons of nominal tonnage;

[0170] The sizes of other components are designed according to the strength and billet size, which will not be described in detail.

[0171] Compared with example 1, the assembly height of example 2 is reduced by about 0.5 meters, and the tonnage of the device is also reduced by about 50%. Therefore, the manufacturing cost of example 2 is lower, but the billet size that can be extruded by this example is smaller, and the coverage of the research range is reduced.

[0172] ​The hydraulic control system of the embodiment is completely same as that of embodiment 1, only the component selection can be adjusted appropriately, the hydraulic main pump 17, the pneumatic plunger pressure stabilizing system 24 and the liquid booster 20 can all be selected in smaller specifications, so that the construction cost can be further reduced.

[0173] Embodiment 3

[0174] The embodiment mainly makes a reasonable prediction on the equipment specifications of the device developed to pilot engineering and large-scale industrialization, including the theoretical calculation results of the main body size and tonnage of the equipment, as shown in Table 1.

[0175] The equipment specifications shown in Table 1 all adopt the design configuration of the attached Figure 5 Compared with the attached Figure 4 , the changes of the new configuration mainly include: first, the reciprocating extrusion equipment adopts an above-ground and underground installation structure, and the F beam 302 is flush with the ground of the plant. Second, the extrusion cylinder 7 adopts a track moving design. When the billet is loaded or unloaded, the extrusion cylinder 7 is moved out from the middle area of the E beam 301 and the F beam 302 of the equipment by means of a moving push rod, until the cavity opening is not covered by the equipment when the discharge opening is loaded. Then the plant overhead crane is used for loading or unloading. In addition, an auxiliary discharge push rod is also needed below the extrusion cylinder in the moved-out state. The moving push rod of the extrusion cylinder and the auxiliary discharge push rod can be driven by hydraulic drive or electric screw drive.

[0176] The attached Figure 5 brings the main advantage of reducing the total height of the equipment. As can be seen from Table 1, when the tonnage of the equipment reaches 25,000 tons, the ground height is 11.5 m, which is basically within the acceptable range of a conventional large industrial plant. In addition, since the weight of the extruded billet has exceeded the normal operating capacity of the worker's arm, a mechanical plant overhead crane must be used to complete the loading and unloading, and after the extrusion cylinder 7 is moved out of the coverage range of the equipment, the loading and unloading operation is more convenient and safer.

[0177] Figure 5 The moving track 309 in the attached and the upper support 308 of the extrusion cylinder all belong to the conventional heavy load bearing components of the equipment, and the embodiment does not make any scheme limitation.

[0178] Figure 2 The hydraulic control system of the embodiment also adopts the principles of the attached Figure 3 and the attached , only the selection of all hydraulic components needs to be adjusted adaptively to match the tonnage and extrusion speed requirements of the equipment.

[0179] Table 1

[0180]

[0181] The above is only several typical device configurations and corresponding typical operation schemes proposed by the present application, and does not limit the present application in any way. Any simple modification, change and equivalent change made to the above embodiments according to the essence of the present application still belongs to the protection scope of the technical solutions of the present application.

Claims

1. A continuous reciprocating extrusion apparatus, characterised in that: The device comprises an upper hydraulic cylinder (5), an upper ejector rod (6), a lower hydraulic cylinder (10), a lower ejector rod (9), a sandglass-shaped cavity extrusion cylinder (7), and a force-bearing component (3); the force-bearing component (3) is used to ensure that the extrusion cylinder (7) can be reliably fixed on the equipment frame; during the reciprocating extrusion process, no displacement is expected to occur between the extrusion cylinder (7) and the equipment frame; the upper ejector rod (6) is driven by the upper hydraulic cylinder (5) and can perform up-and-down movement, and the lower ejector rod (9) is driven by the lower hydraulic cylinder (10) and can perform up-and-down movement; the metal blank (8) is loaded into the sandglass-shaped cavity extrusion cylinder (7), and the upper and lower hydraulic cylinders simultaneously apply equal pressure to tightly extrude the metal blank (8) in the cavity of the sandglass-shaped cavity extrusion cylinder (7); after ensuring pre-tightening, the upper ejector rod (6) and the lower ejector rod (9) perform synchronous movement, and the synchronous reciprocating movement of the upper ejector rod (6) and the lower ejector rod (9) forces the metal blank (8) in the sandglass-shaped cavity extrusion cylinder (7) to also realize reciprocating movement at the same frequency and repeatedly pass through the necking part in the middle of the sandglass-shaped cavity extrusion cylinder (7), so as to realize reciprocating extrusion.

2. The continuous reciprocating extrusion apparatus according to claim 1, characterized by: The equipment frame comprises an upper cross beam (1), a lower cross beam (4), and a column (2); all are force-bearing structural components, and the structure and layout are implemented by using the design scheme of the general hydraulic equipment in the industry.

3. The continuous reciprocating extrusion apparatus according to claim 1, characterized by: The upper ejector rod (6) and the lower ejector rod (9) have the same diameter and the same material.

4. The continuous reciprocating extrusion apparatus according to claim 1, characterized by: The upper hydraulic cylinder (5) and the lower hydraulic cylinder (10) adopt coaxial layout and equal-section design.

5. The continuous reciprocating extrusion apparatus according to claim 1, characterized by: The synchronous movement required by the upper ejector rod (6) and the lower ejector rod (9) depends on the synchronous driving of the upper hydraulic cylinder (5) and the lower hydraulic cylinder (10); and the upper and lower hydraulic cylinders realize synchronous movement through a set of hydraulic control systems.

6. The continuous reciprocating extrusion apparatus according to claim 1, characterized by: The hydraulic control system comprises a plunger type liquid booster (20) and a pneumatic plunger pressure stabilizing system (24); the hydraulic control system further comprises a plurality of hydraulic valves (11, 12, 13, 14, 15, 18, 19, 21, 22, 23).

7. The method of extrusion deformation of a continuous reciprocating extrusion apparatus according to any one of claims 1 to 6, characterized in that: When two liquid return valves (12, 19) are in a closed state, a hydraulic main pump (17) is opened, and the remaining valves (11, 13, 14, 15, 18, 21, 22, 23) are in an open state. Under the action of the hydraulic main pump, two hydraulic cylinders (5, 10), as well as hydraulic pipelines, the plunger type liquid booster, and the pneumatic plunger pressure stabilizing system all enter the pressure charging / liquid charging state; when the extrusion pre-tightening force generated by the two hydraulic cylinders reaches the process set value, the pre-tightening process ends; When valve 23 is closed and valve 22 is opened, the pneumatic plunger pressure stabilizing system (24) implements independent pressure stabilization on the lower hydraulic cylinder; valve (1121) is opened, and valves (18, 13) are closed; the plunger type liquid booster (20) starts to operate, and the hydraulic medium flows from the lower hydraulic cylinder into the upper hydraulic cylinder under the action of the booster; When the valve (23) is opened, the valve (22) is closed, the pneumatic plunger pressure stabilizing system (24) implements single pressure stabilization on the upper hydraulic cylinder; the valves (11, 21) are closed, and the valves (18, 13) are opened; after the valve state is switched, the flow path of the hydraulic medium is reversed, flowing from the upper hydraulic cylinder into the plunger type liquid booster (20) and then into the lower hydraulic cylinder.

8. The extrusion deformation method of a continuous reciprocating extrusion apparatus according to claim 7, characterized by: The reciprocating extrusion device further comprises an extrusion filler, which is loaded into the sandglass-shaped cavity of the extrusion cylinder (7) simultaneously with the metal blank (8); the loading sequence is as follows: a first portion of the filler, the heated metal blank, and a second portion of the filler are loaded into the cavity from the upper end of the cavity in sequence; the first and second portions of the extrusion filler are equal in amount, and each portion is exactly capable of filling the necked region of the extrusion cavity to the brim when converted to a compacted volume.

9. The extrusion deformation method of a continuous reciprocating extrusion apparatus according to claim 7, characterized by: The filler takes spherical or near-spherical granular material of ceramic or heat-resistant metal as a skeleton component, the diameter of the granular material is 1.5-5.0 mm, and the volume fraction is controlled to be 35-75%; in addition to the skeleton component, other auxiliary components are also required, including three types of void fillers, high-temperature binders, and surface tension agents.

10. The extrusion deformation method of a continuous reciprocating extrusion apparatus according to claim 7, characterized by: The extrusion filler is composed of the following components in volume fractions: a) 40-60% of 2.0-2.5 mm zirconia spherical granules as a skeleton; b) 10-20% of glass powder with a softening point of 500-600 ℃; c) 5-15% of feldspar powder forming a liquid phase at 600 ℃; d) 3-8% of water glass for cold-state pre-solidification; The filling material shows Bingham fluid behavior under the co-extrusion condition of 500-700℃, three-way compressive stress absolute value ≥120MPa, yield stress 80-110MPa, apparent viscosity 3×103-2×104Pa·s, shear rate 10s -1 , and the co-extrusion interface with the metal blank does not penetrate each other.

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