Hydraulic-pneumatic mixed forming device and forming method

Abstract

The invention belongs to the field of hydraulic forming devices, and discloses a hydraulic-pneumatic mixed forming device which comprises a female die, a pressure bin, a piston and an electromagnetic driving assembly. The piston is inserted into the pressure bin in an axially movable mode. A to-be-machined part is clamped and fixed between the female die and the pressure bin in the forming process, a forming cavity is defined by the female die and the to-be-machined part, the pressure bin, the piston and the to-be-machined part are matched to form a pressure cavity, and the pressure cavity is filled with a forming medium. The electromagnetic driving assembly generates pulse driving force to drive the piston to move at a high speed in the pressure bin, transient high pressure is applied to the forming liquid in the pressure cavity, the forming liquid rises to make contact with a to-be-machined part to be vaporized and expanded to achieve secondary pressurization, and the plastic deformation capacity of a material is improved through the high-strain-rate effect and the high-temperature softening effect of metal. According to the device, a high-speed dynamic loading mode is achieved through the electromagnetic driving assembly and the phase change of the forming liquid, the strain localization phenomenon in the material forming process is effectively restrained, and the forming limit of low-plasticity materials is broken through.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydraulic forming devices, and more particularly relates to a hydraulic-gas pressure mixed forming device and a forming method. BACKGROUND

[0002] In the field of metal sheet forming, the hydraulic forming technology is widely used due to its low mold cost and good surface quality of formed parts. However, when processing low elongation metal materials such as aluminum alloy and magnesium alloy, the liquid pressure distribution is uneven and the plastic deformation capacity of the material is limited, which easily causes strain localization in the deformation concentration area, and further causes material cracking defects. In addition, if the forming precision of the part is further improved, expensive pressure increasing equipment is needed to provide higher hydraulic forming force. This phenomenon is particularly prominent in the forming of complex curved surface components, which seriously restricts the product quality and production efficiency. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide a hydraulic-gas pressure mixed forming device and a forming method to solve the technical problems of poor forming effect when processing low elongation metal materials and high cost of increasing hydraulic forming force in the prior art.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is: Provided is a hydraulic-gas pressure mixed forming device, comprising: a female die having a forming surface for forming; the female die has a heating member which is arranged outside the female die.

[0005] a pressure chamber and a piston, the piston being movably inserted into the pressure chamber; a workpiece to be processed is clamped between the female die and the pressure chamber, the female die and the workpiece to be processed form a forming cavity, the pressure chamber, the piston and the workpiece to be processed form a pressure chamber, the pressure chamber is filled with forming liquid; an electromagnetic drive assembly is drivingly connected with the piston for driving the piston to move in the pressure chamber to increase the pressure of the forming liquid.

[0006] The workpiece to be processed is clamped between the female die and the pressure chamber; the heating member on the female die heats and keeps warm the workpiece to be processed; Pulse current is passed into the electromagnetic coil of the electromagnetic drive assembly, the magnetic field generated by the electromagnetic coil and the repulsive force generated by the magnetic member, thereby driving the piston to move in the pressure chamber to pressurize the workpiece to be processed; the current in the electromagnetic coil gradually increases to gradually increase the magnetic field strength of the electromagnetic coil to control the piston to rise into the pressure chamber at a certain rate; The piston pushes the forming liquid to rise to contact the workpiece to be processed, and the workpiece to be processed is formed by being pressed against the forming surface of the female die under the action of the hydraulic pressure of the forming liquid and the vaporization pressure increasing force of the forming liquid.

[0007] As a further improvement of the above technical solution: Optionally, the electromagnetic drive assembly comprises an electromagnetic coil and a magnetic piece, the magnetic piece is connected to the piston, and the electromagnetic coil is located below the magnetic piece; after the electromagnetic coil is electrified, a magnetic field with the same magnetic pole as the magnetic piece is generated to generate repulsive force to drive the piston to move in the pressure chamber.

[0008] Optionally, the electromagnetic drive assembly further comprises an insulating shell, and the electromagnetic coil is fixed in the insulating shell.

[0009] Optionally, a die holder is provided, the pressure chamber is supported on the upper end of the die holder, and the electromagnetic drive assembly is mounted on the die holder and located below the piston.

[0010] Optionally, the workpiece to be processed is a workpiece after solid solution heat treatment.

[0011] Optionally, a heat insulation plate is further provided between the workpiece to be processed and the pressure chamber, and the heat insulation plate has a through hole in communication with the pressure chamber.

[0012] Optionally, the vaporization temperature of the forming liquid is lower than the solid solution temperature of the workpiece to be processed.

[0013] Compared with the prior art, the present application has the following advantages: The hydraulic forming device provided by the present application comprises a female die, a pressure chamber, a piston and an electromagnetic drive assembly. The female die is provided with a forming surface for defining the final shape contour of the workpiece. The female die is further provided with a heating piece arranged outside the female die for providing the heat required for the phase change of the forming liquid. The pressure chamber and the piston are movably connected, and the piston is movably inserted into the pressure chamber. The workpiece to be processed is clamped and fixed between the female die and the pressure chamber during the forming process, and the female die and the workpiece to be processed jointly form a forming cavity, while the pressure chamber, the piston and the workpiece to be processed cooperatively form a pressure chamber filled with a forming medium for transmitting pressure. The electromagnetic drive assembly is mechanically connected to the piston and generates a controllable pulse driving force through electromagnetic induction, which can accurately drive the piston to move at high speed in the pressure chamber. This movement can apply transient high pressure to the forming liquid in the pressure chamber, and the forming liquid rises to contact the workpiece to be processed to cause vaporization and expansion to realize secondary pressurization, thereby significantly improving the plastic deformation ability of the material by using the high strain rate effect and high temperature softening effect. Compared with the traditional hydraulic forming equipment, the high-speed dynamic loading mode realized by the electromagnetic drive assembly and the phase change of the forming liquid can effectively suppress the strain localization phenomenon during the forming process of the material, thereby breaking through the forming limit of low plasticity materials such as aluminum alloy. Since the workpiece to be processed undergoes a solid solution and quenching process during the deformation process, the mechanical properties of the formed part are also improved. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Fig. 1 This is a schematic diagram of the first working state of the hydraulic forming apparatus of this application; Fig. 2 This is a schematic diagram of the second working state of the hydraulic forming apparatus of this application; Fig. 3 This is a schematic diagram of the third working state of the hydraulic forming apparatus of this application; Fig. 4 This is a schematic diagram of the structure of the workpiece after being formed by the hydraulic forming device of this application.

[0016] The following are the labeling elements in the figure: 1. Die; 11. Heating element; 2. Pressure chamber; 3. Piston; 4. Forming cavity; 5. Pressure chamber; 6. Electromagnetic drive assembly; 61. Electromagnetic coil; 62. Magnetic component; 63. Insulating shell; 7. Mold frame; 8. Heat insulation plate; 9. Workpiece to be processed. Detailed Implementation

[0017] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0018] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0019] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0021] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0022] like Figs. 1 to 4 As shown, this application provides a hydroforming apparatus, which includes a die 1, a pressure chamber 2, a piston 3, and an electromagnetic drive assembly 6. The die 1 has a forming surface to define the final shape contour of the workpiece. The pressure chamber 2 and the piston 3 are fitted together in a relatively movable manner, with the piston 3 inserted into the pressure chamber 2 in an axially movable manner. During the forming process, the workpiece 9 is clamped and fixed between the die 1 and the pressure chamber 2. The die 1 and the workpiece 9 together form a forming cavity 4. Simultaneously, the pressure chamber 2, the piston 3, and the workpiece 9 cooperate to form a pressure chamber 5, which is filled with a forming medium for transmitting pressure. The electromagnetic drive assembly 6 is mechanically connected to the piston 3, generating a controllable pulse driving force through electromagnetic induction, enabling precise high-speed movement of the piston 3 within the pressure chamber 2. This movement applies transient high pressure to the forming fluid within the pressure chamber 5, and the high strain rate effect generated by the electromagnetic drive significantly enhances the plastic deformation capacity of the material. Compared with traditional hydraulic forming equipment, this device, through the dynamic loading method achieved by the electromagnetic drive component 6, can effectively suppress the strain localization phenomenon during the material forming process, thereby breaking through the forming limit of low plasticity materials such as aluminum alloys, and improving the mechanical properties of the formed parts.

[0023] In one specific embodiment of this application, the electromagnetic drive assembly 6 includes an electromagnetic coil 61 and a magnetic component 62. The magnetic component 62 is fixedly mounted on the bottom of the piston 3, forming a rigid connection with the piston 3. The electromagnetic coil 61 is arranged directly below the magnetic component 62. When the electromagnetic coil 61 is energized, the direction of the magnetic field it generates is the same as the direction of the magnetic poles of the magnetic component 62. According to the principle of repulsion between like poles, a transient repulsive force will be generated between the electromagnetic coil 61 and the magnetic component 62. This repulsive force is transmitted to the piston 3 through the magnetic component 62, driving the piston 3 to move rapidly along the axial direction of the pressure chamber 2. By adjusting the current parameters of the electromagnetic coil 61, the magnitude and duration of the repulsive force can be precisely controlled, thereby achieving precise control of the piston 3's movement speed and displacement. This electromagnetic drive method has technical advantages such as fast response speed, high control precision, and good repeatability, and can provide a stable and reliable high-frequency impact load for the hydroforming process.

[0024] In one specific embodiment of this application, the electromagnetic drive assembly 6 further includes an insulating housing 63. The insulating housing 63 is made of high-strength insulating material, and the electromagnetic coil 61 is securely mounted within the insulating housing 63 by mechanical fixing, ensuring that the coil maintains a stable position during operation. The insulating housing 63 not only provides reliable mechanical support and protection for the electromagnetic coil 61, but also effectively isolates the coil from electrical contact with the external environment, preventing potential safety hazards caused by high-voltage current.

[0025] In one specific embodiment of this application, the hydroforming apparatus includes a mold frame 7. The mold frame 7 adopts a rigid frame design, providing stable mechanical support for the entire apparatus. The pressure chamber 2 is precisely mounted on the upper end of the mold frame 7 via a positioning structure. The electromagnetic drive assembly 6 is integrated into the internal space of the mold frame 7, and its mounting position is located directly below the piston 3 to ensure effective transmission of driving force.

[0026] In one specific embodiment of this application, the workpiece 9 is a metal sheet that has undergone solution heat treatment. During solution heat treatment, the sheet undergoes heating and holding to fully dissolve the alloying elements, followed by rapid quenching. This heat treatment process significantly improves the microstructure of the workpiece 9, achieving a supersaturated solution state of the alloying elements within the matrix. This microstructure allows the material to exhibit superior plastic deformation capacity during subsequent hydroforming, while ensuring the mechanical properties of the formed workpiece. The workpiece 9 after solution heat treatment exhibits a higher strength-toughness ratio, better adapting to the high strain rate forming conditions of electromagnetically driven hydroforming, and effectively reducing the risk of cracking defects during the forming process.

[0027] In one specific embodiment of this application, the die 1 further integrates a heating element 11. The heating element 11 is arranged around the outer periphery of the forming cavity 4, forming an integrated structure with the die 1. The heating element 11 operates by resistance heating or induction heating, and can control the temperature of the workpiece 9 to be processed. During the forming process, the heating element 11 can heat the workpiece 9 to the temperature range required for solution heat treatment, and achieve precise temperature control inside the mold. This not only integrates the forming and heat treatment processes, but also ensures a uniform temperature field distribution. Through in-mold solution heat treatment, the workpiece 9 can complete the solution transformation of the material structure under optimal temperature conditions, creating favorable conditions for subsequent forming processes.

[0028] In one specific embodiment of this application, the hydroforming apparatus also includes a heat insulation plate 8 as a protective component. The heat insulation plate 8 is made of a high-temperature resistant composite material, and its thickness effectively blocks heat conduction. This heat insulation plate 8 is mounted at the contact interface between the workpiece 9 and the pressure chamber 2, and its surface is machined with through holes that communicate with the pressure chamber 5, ensuring that the forming fluid pressure can be uniformly transmitted to the workpiece 9. The main function of the heat insulation plate 8 is to isolate the high-temperature workpiece 9 from the pressure chamber 2, preventing thermal damage or performance degradation of the pressure chamber 2 during the high-temperature forming process. The through holes ensure heat insulation without affecting the pressure transmission efficiency during the hydroforming process. The introduction of the heat insulation plate 8 improves the reliability and service life of the apparatus under high-temperature conditions.

[0029] In one specific embodiment of this application, the forming fluid filling the pressure chamber 5 is a vaporizable forming fluid with specific vaporization characteristics. When this forming fluid comes into contact with the high-temperature workpiece 9 through the extrusion of the piston 3, a rapid phase change occurs at the interface, transforming it from a liquid to a gaseous state. During vaporization, the liquid expands rapidly, creating a high-pressure steam environment within the sealed forming chamber 4. Furthermore, the phase change process absorbs a large amount of heat, which helps control the local temperature distribution of the workpiece 9. The dynamic change in steam pressure provides additional forming force for sheet metal forming. This additional pressure generated by the phase change is characterized by uniform distribution and rapid response, effectively compensating for the uneven pressure distribution defects in traditional hydraulic forming.

[0030] In one specific embodiment of this application, the selected vaporizable forming fluid possesses specific thermophysical properties, and its vaporization temperature must be lower than the temperature range required for solution heat treatment of the workpiece 9. Specifically, when the forming fluid comes into contact with the workpiece 9 at its solution temperature, a controllable vaporization reaction occurs immediately, without insufficient vaporization due to insufficient temperature or excessive vaporization due to excessive temperature. This optimized configuration of temperature parameters enables the forming fluid to achieve a stable phase change process under optimal operating conditions, thereby providing continuous and uniform vapor pressure for sheet metal forming.

[0031] Because different liquid media have different boiling point characteristics, under the condition that the single discharge energy of the electromagnetic drive component 6 is fixed, the vaporization behavior of the liquids varies significantly. Specifically, liquids with lower boiling points are more likely to completely vaporize when they come into contact with the high-temperature workpiece 9, and the volume expansion force generated by their phase change dominates the total forming force; conversely, liquids with higher boiling points need to absorb more heat energy for vaporization, which often leads to incomplete vaporization. In this case, the forming force mainly comes from the kinetic energy transfer of the liquid medium.

[0032] Taking water and trichlorofluoroethane as typical media as examples: When water is used as the forming fluid, its boiling point reaches 100℃, making complete vaporization difficult under limited thermal energy conditions; most of the energy is converted into the kinetic energy of the liquid flow. This characteristic makes it suitable for processes requiring rapid shaping of simple contoured workpieces. However, when trichlorofluoroethane is used as the forming fluid, its boiling point is approximately 47℃, allowing for rapid and complete vaporization under the same thermal conditions, converting most of the energy into vapor pressure energy. This uniformly distributed vapor pressure field can simultaneously apply sufficient pressure to various areas of complex curved surfaces, making it particularly suitable for forming high-precision complex workpieces with deep cavities, sharp angles, etc., significantly improving the fit between the workpiece and the forming surface of the die 1. By selecting a medium with an appropriate boiling point for different forming requirements, precise control of the forming process can be achieved.

[0033] The hydraulic forming apparatus of this application also integrates a dual-sensor collaborative control system, an integrated detection and control unit designed to achieve precise matching between vaporization pressure parameters and mold temperature, and to meet the solid solution forming process requirements of the workpiece 9. This system achieves precise monitoring of the forming process by arranging a sensor network at key locations on the die 1 and pressure chamber 2 of the hydraulic forming apparatus. A dedicated mounting hole is machined on the side wall of the pressure chamber 2, and a high-temperature, high-pressure resistant pressure sensor is installed inside the hole. The probe end of the sensor is precisely embedded in the inner wall of the chamber, ensuring its sensing surface is flush with the inner wall of the pressure chamber 5. This installation method can accurately capture key parameters such as the peak intensity and duration of the pressure wave during the forming process. A threaded mounting hole is machined on the side of the die 1, and a temperature sensor is screwed into the hole. The sensor probe maintains close contact with the inner wall of the die 1, and its placement is at a reasonable distance of 10 to 20 mm from the heating element 11. This temperature sensor has dual functions of temperature acquisition and temperature control feedback, and can monitor mold temperature changes in real time.

[0034] The temperature control mechanism is achieved through closed-loop control. The temperature sensor continuously collects the temperature data of the die 1. When the detected temperature is lower than the lower limit required for solution treatment of the workpiece 9, the system sends a command to the heating element 11 to increase the heating power. When the temperature exceeds the set upper limit, the heating power is automatically cut off to prevent overheating. This precise temperature control ensures that the workpiece 9 is always within the optimal solution treatment temperature range.

[0035] The pressure detection system continuously monitors the dynamic pressure within the forming cavity 4 using pressure sensors, and the obtained data provides an important basis for optimizing process parameters. The operating data from the pressure and temperature sensors are collaboratively analyzed by the central processing unit, forming a key detection and control loop to ensure forming quality.

[0036] The hydraulic forming apparatus of this application also integrates a circulating filtration unit to address issues such as dissolved gas release, temperature fluctuations, and solid impurity contamination of the forming fluid during use, forming a closed-loop fluid control system that works in conjunction with the pressure chamber 2. This unit utilizes flow holes located near the bottom and top of the pressure chamber 2, each fitted with a high-pressure resistant sealing joint. These holes are connected to the main body of the circulating filtration unit via pressure-resistant hoses, creating a closed-loop circulation path where fluid flows out of the pressure chamber 2, is processed, and then returns to the pressure chamber 2. Inside the circulating filtration unit, a pump, heat exchanger, and filter assembly are connected in series according to the fluid flow direction. Through the synergistic effect of power drive, temperature regulation, and impurity filtration, the physical properties and chemical stability of the forming fluid meet the requirements of the continuous forming process.

[0037] Regarding temperature control, after the forming process is completed, the forming fluid, whose temperature has risen due to absorbing heat from the workpiece, flows through a heat exchanger driven by a pump. Through heat exchange with the cooling medium, the temperature is restored to a stable room temperature. This process eliminates the liquid temperature rise caused by a single forming operation, providing repeatable initial temperature conditions for subsequent forming experiments and ensuring the consistency and comparability of process parameters. Regarding impurity filtration, trace metal fragments or wear particles from moving parts that may be generated during the forming process will flow into the circulation loop with the liquid. The filter effectively traps and removes these solid impurities, preventing them from re-entering the pressure chamber 5 with the liquid, thus preventing impurities from adversely affecting the uniformity of pressure transmission, sealing reliability, and workpiece surface quality. This unit maintains the cleanliness and thermophysical properties of the forming fluid through continuous temperature control and impurity filtration, achieving liquid recyclability.

[0038] This application also provides a forming method using a hydroforming apparatus, the method specifically including the following process steps: First, the workpiece 9, after solution heat treatment, is positioned between the die 1 and the pressure chamber 2, forming a closed forming cavity 4 and a pressure chamber 5. The heating element 11 integrated on the die 1 heats the workpiece 9 and maintains it within the temperature range required for solution treatment, ensuring the material is in its optimal plastic state. The specific temperature range depends on the solution temperature corresponding to the material type of the workpiece; for example, the solution temperature for 6061 aluminum alloy needs to be controlled between 510℃ and 530℃, and the solution temperature for 6063 aluminum alloy needs to be controlled between 530℃ and 550℃.

[0039] This application applies to solution treatment of aluminum alloys, specifically referring to a heat treatment process for heat-treatable aluminum alloys (including but not limited to Al-Mg-Si series 6xxx, Al-Cu series 2xxx, and Al-Zn-Mg-Cu series 7xxx series aluminum alloys). The aluminum alloy workpiece to be treated is placed in a heating device and heated to a specific temperature range higher than the critical temperature corresponding to the solubility curve of solute atoms (such as Mg, Si, Cu, Zn, etc.) in the aluminum matrix, but lower than the overheating temperature of the aluminum alloy. The temperature is held for a preset duration (adjusted according to the workpiece thickness and alloy composition) to fully dissolve the solute atoms, which originally existed as a second phase within the aluminum alloy, into the aluminum matrix, forming a uniformly composed supersaturated solid solution. Subsequently, a rapid cooling method (coolant in a pressure chamber impacting the surface of the sheet) is used to suppress the precipitation of solute atoms from the aluminum matrix during cooling, preventing the formation of coarse second phases and forcing the formation of a uniformly composed supersaturated solid solution, thus preserving the potential of solute atoms for subsequent forming and aging strengthening.

[0040] During the forming stage, a pulsed current is input to the electromagnetic coil 61 of the electromagnetic drive assembly 6. The dynamic magnetic field generated by this current interacts with the magnetic component 62 fixed on the piston 3, producing a controllable electromagnetic repulsive force. By gradually increasing the input current of the electromagnetic coil 61, the magnetic field strength is increased, thereby driving the piston 3 to rise rapidly within the pressure chamber 2. The movement of the piston 3 gradually compresses the forming liquid in the pressure chamber 5. When the liquid level rises to contact the high-temperature workpiece 9, a vaporization phase change occurs, generating an additional vapor pressure field. Under the combined action of liquid pressure and vapor pressure, the workpiece 9 undergoes plastic deformation and tightly adheres to the forming surface of the die 1, ultimately forming a standard shaped workpiece.

[0041] The aluminum alloy workpiece, after solution treatment, rapid forming, and rapid cooling, is then placed in a temperature-controlled heating device. It is held at a specific temperature range for a preset duration (dynamically adjusted according to the alloy type). By precisely controlling the heating temperature and holding time, the solute atoms in the supersaturated solid solution precipitate as strengthening phases in a uniformly dispersed manner. To avoid interference from natural aging, the interval between the completion of solution cooling and the start of aging must not exceed 4 hours, and the heating rate must be controlled at 5~10℃ / min to ensure temperature uniformity. The core purpose of artificial aging is to significantly improve the strength, hardness, and other mechanical properties of the aluminum alloy by controlling the size, distribution, and density of the strengthening phases, while simultaneously eliminating residual stress generated during rapid forming and stabilizing the dimensional accuracy of the workpiece.

[0042] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A hydraulic-pneumatic hybrid forming apparatus, characterized in that, include: The die (1) has a forming surface for forming; A pressure chamber (2) and a piston (3) are provided, wherein the piston (3) is movably inserted into the pressure chamber (2); the workpiece (9) to be processed is clamped between the die (1) and the pressure chamber (2), wherein the die (1) and the workpiece to be processed enclose to form a forming cavity (4), wherein the pressure chamber (2), the piston (3) and the workpiece to be processed enclose to form a pressure cavity (5), wherein the pressure cavity (5) is filled with forming fluid; An electromagnetic drive assembly (6) is driven to the piston (3) to drive the piston (3) to move in the pressure chamber (2) to increase the pressure of the forming fluid.

2. The hydroforming apparatus as described in claim 1, characterized in that, The electromagnetic drive assembly (6) includes an electromagnetic coil (61) and a magnetic component (62). The magnetic component (62) is connected to the piston (3), and the electromagnetic coil (61) is located below the magnetic component (62). When the electromagnetic coil (61) is energized, it generates a magnetic field with the same magnetic pole as the magnetic component (62) to generate a repulsive force to drive the piston (3) to move in the pressure chamber (2).

3. The hydroforming apparatus as described in claim 2, characterized in that, The electromagnetic drive assembly (6) also includes an insulating housing (63), and the electromagnetic coil (61) is fixed inside the insulating housing (63).

4. The hydraulic forming apparatus as described in claim 2, characterized in that, Includes a mold frame (7), the pressure chamber (2) is supported on the upper end of the mold frame (7), and the electromagnetic drive assembly (6) is installed on the mold frame (7) and located below the piston (3).

5. The hydroforming apparatus according to any one of claims 1 to 4, characterized in that, The workpiece to be processed (9) is a workpiece that has undergone solution heat treatment.

6. The hydroforming apparatus according to any one of claims 1 to 4, characterized in that, The die (1) also has a heating element (11) which surrounds the outside of the forming cavity (4).

7. The hydroforming apparatus according to any one of claims 1 to 4, characterized in that, It also includes a heat insulation plate (8) placed between the workpiece (9) and the pressure chamber (2), the heat insulation plate (8) having a through hole communicating with the pressure chamber (5).

8. The hydroforming apparatus according to any one of claims 1 to 4, characterized in that, The forming liquid is a vaporizable forming liquid, and the forming liquid forms pressurized steam after contacting the workpiece (9).

9. The hydroforming apparatus as described in claim 8, characterized in that, The vaporization temperature of the forming liquid is lower than the solid solution temperature of the workpiece (9).

10. A forming method based on the hydroforming apparatus according to any one of claims 1 to 9, characterized in that, Includes the following steps: After solution heat treatment, the workpiece (9) is sandwiched between the die (1) and the pressure chamber (2); the heating element (11) on the die (1) heats and keeps the workpiece (9) warm; A pulse current is passed into the electromagnetic coil (61) of the electromagnetic drive assembly (6). The magnetic field generated by the electromagnetic coil (61) and the magnetic component (62) generate a repulsive force, thereby driving the piston (3) to move in the pressure chamber (2) to pressurize the workpiece (9). The current in the electromagnetic coil (61) is gradually increased to gradually increase the magnetic field strength of the electromagnetic coil (61) so as to control the piston (3) to rise into the pressure chamber (5) at a certain rate. The piston (3) pushes the forming liquid up to contact the workpiece (9) to be processed. The workpiece (9) is formed by the liquid pressure of the forming liquid and the vaporization pressure of the forming liquid against the forming surface of the die (1).

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