Apparatus and method for electroexplosive forming or welding of tubular components based on metal foil array

Abstract

This application belongs to the field of pipe forming and manufacturing, specifically disclosing an apparatus and method for electro-explosive forming or welding of pipes based on a metal foil array. In this application, the metal foil array consists of multiple metal foils uniformly distributed circumferentially. These foils undergo simultaneous phase transitions and generate shock waves upon the application of a pulsed current, driving deformation in the corresponding area of ​​the pipe to be processed. By connecting the metal foil arrays in parallel, multiple foils simultaneously conduct and undergo phase transitions upon the application of a pulsed current, overcoming the limitation of traditional electro-explosive technology in applying to large-sized curved workpieces. An insulating positioning block controls the radial distance between the pipe and the forming mold, better constraining the forming effect. This application uses a metal foil array as the electro-explosive material. Metal foil is a disposable consumable; its raw materials are inexpensive, easy to process, and readily replaceable, thus negligible impact of multiple high-voltage pulses on the lifespan of the discharge device.

Description

Technical Field

[0001] This application belongs to the field of pipe forming and manufacturing, and more specifically, relates to an apparatus and method for electro-explosive forming or welding of pipes based on metal foil arrays. Background Technology

[0002] High-speed forming is a processing technology that utilizes high-density energy, such as explosive shock waves or pulsed electromagnetic forces, as impact loads. Electro-explosive forming of metal foil, a newly proposed high-speed forming technology, boasts advantages such as low cost, high efficiency, high controllability, and ease of automation. Its main principle involves applying a pulsed high voltage to the metal foil, causing it to undergo six phase transition stages: solid-state heating, liquefaction, liquid-state heating, vaporization, breakdown ionization, and plasma evolution. During these phase transitions, the generated vaporization and plasma shock waves act on the workpiece, driving it to deform and collide with the mold at high speed, ultimately forming the desired shape. The electro-explosive device is relatively simple and low-cost. The forming process requires no heating or continuous friction, avoids the formation of a heat-affected zone, and minimizes the formation of intermetallic compounds, making it highly valuable for practical applications and suitable for widespread adoption.

[0003] Currently, metal foil electro-explosion forming technology has been initially applied to the processing and forming of two-dimensional planar components. However, limited by the basic principles of electro-explosion, this method faces challenges in processing curved components: First, the successful execution of electro-explosion depends on the formation of plasma channels and the accumulation of deposition energy. However, existing electro-explosion technologies struggle to effectively form plasma channels with controllable length and curvature on the surface of curved workpieces. The uncontrollability of plasma channel formation is specifically manifested in the uncertainty of the explosion point and explosion time. The former makes it difficult to guarantee the effective area of ​​the explosion force load and the forming accuracy, while the latter prevents the effective accumulation of deposition energy, making it difficult to achieve the expected forming degree. In addition, other problems exist, such as the relatively concentrated impact force of a single metal foil electro-explosion, resulting in a small deformation area of ​​the processed workpiece. In the forming of large-size tubes, multiple processing steps are required, making the operation more complex. Furthermore, for workpieces with relatively enclosed processing areas, such as long tubes deforming inwards, air between the workpiece and the mold or other workpieces is difficult to expel at the moment of electro-explosion deformation. Deformation compresses the air, and air resistance consumes the explosion energy, weakening the forming effect. Patent CN113458234A discloses an apparatus and method for forming a workpiece using an electro-hydraulic explosion shock wave. The method involves passing a pulsed current through a pulsed power supply system onto the metal foil. Under the action of the pulsed current, the metal foil explodes, generating a violent shock wave. During the explosion, the metal foil undergoes an oxidation-reduction reaction with the liquid environment, releasing a large amount of energy. Under the action of the shock wave and energy, the metal workpiece undergoes a mechanical response and is thus formed. However, this method has the following drawbacks: 1) Electro-hydraulic explosion requires the entire apparatus, especially the metal foil, to be immersed in a water environment, making it unsuitable for workpieces that are not suitable for immersion in water. Furthermore, under high current, many metal workpieces will chemically react with water, generating byproducts that damage the workpiece's strength; 2) Electro-hydraulic explosion uses a uniform metal foil with no obvious weak points in its structure. Under the action of the pulsed current, the metal foil may explode at any point, resulting in random loading of the explosion impact force, which greatly affects the forming accuracy; 3) Due to the properties of the electro-hydraulic fluid, any shock wave generated by the electro-explosion will be transformed into a spherical shock wave under liquid constraint. Therefore, this technology can only form spherical workpieces.

[0004] In summary, the electro-explosive forming technology for large axisymmetric curved surface workpieces, especially pipes, needs further development. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide an apparatus and method for electro-explosion forming or welding of tubular components based on metal foil arrays, which aims to solve the problem that traditional electro-explosion technology cannot be applied to large-size curved workpieces.

[0006] The first aspect of this application relates to an apparatus for electroexplosive forming or welding of tubular components based on a metal foil array, the apparatus comprising:

[0007] The metal foil array consists of multiple metal foils that are evenly distributed circumferentially. These foils are used to simultaneously undergo phase change and generate shock waves after a pulse current is applied, thereby driving deformation of the corresponding area of ​​the pipe to be processed.

[0008] The positive and negative electrodes located at both ends of the metal foil array are used to connect to the pulse power supply to supply power to each metal foil in parallel.

[0009] An insulating positioning block, closely attached to the inner surface of the positive and negative electrodes, is used to insulatingly separate the pipe to be processed, component A, and the electrodes. Component A is a forming mold or another pipe to be processed. The radial relative positions of the metal foil array, the pipe to be processed, and component A are constrained, such that component A is placed in the deformation direction of the pipe to be processed, and the metal foil array is located in the opposite direction of the deformation of the pipe to be processed. The two ends of the metal foil array are radially fixed, and the two ends of the pipe to be processed are axially closed, so that the workpiece deformation space between the insulating positioning block and the pipe to be processed is sealed.

[0010] In some implementations, the metal foil array is replaceable, and the number and / or position of the metal foils in the array are adjusted according to forming requirements to adapt to different molds; the size, shape, thickness and / or material of each metal foil is the same and is adjusted according to forming requirements to adjust the magnitude of the impact load.

[0011] It should be noted that the size, shape, thickness, and material of the metal foil in the metal foil array can all be adjusted, affecting the amount of deposition energy, thereby enabling the loading and control of impact loads to achieve the required forming effect.

[0012] In some implementations, the height of the preset explosion points of each metal foil may be the same or different. The preset explosion point is the narrowest position on the cut metal foil, and the height value is adjusted according to the forming requirements to adapt to different molds.

[0013] It should be noted that the number of metal foils, the height of the cut sections, and the position of the metal foils in the metal foil array are all adjustable, thus adapting to more molds and processing workpieces into more shapes. The part that needs to be exploded by the metal foil is cut into a uniform narrow strip without sharp corners, and the current density is higher at the narrowest point, thereby customizing the weak point of the metal foil, better controlling the explosion position, and thus deforming the workpiece at a specific point. Compared with the high speed of the current, the difference in explosion time caused by the height difference is negligible and can still be regarded as simultaneous explosion.

[0014] In some implementations, the height of the preset explosion points of each metal foil may be the same or different, and the preset explosion point is the narrowest position on the cut metal foil.

[0015] In some embodiments, when component A is placed inside the pipe to be processed, the insulating positioning block is a double cylindrical structure with a T-shaped cross-section, the top width of the T-shape matching the diameter of the metal foil, and the bottom width matching the inner diameter of the pipe to be processed; when component A is placed outside the pipe to be processed, the insulating positioning block is a cylindrical structure, the diameter of which matches the inner diameter of the pipe to be processed.

[0016] In some embodiments, the electrode is a ring electrode and cooperates with an insulating positioning block to radially press the edges of both ends of the metal foil array.

[0017] It should be noted that this application preferably uses a ring electrode to apply current to different numbers of metal foils in order to cooperate with more complex molds and achieve multi-point forming.

[0018] In some embodiments, it also includes: a vacuum tube extending from the center hole of the electrode for connecting the workpiece deformation space and the vacuum pump; and a vacuum pump for continuously vacuuming the entire workpiece deformation space to maintain the air pressure in the workpiece deformation direction environment at the time of explosion not exceeding 10 kPa.

[0019] It should be noted that this application optimizes the problem of internal air rebound when performing diameter reduction forming on devices containing air, such as metal pipes with closed ends, by continuously evacuating the workpiece deformation space through the addition of a vacuum tube channel, thereby improving energy utilization and forming or welding quality.

[0020] In some embodiments, it also includes a support block surrounding the outer surface of the metal foil array to prevent leakage of shock waves generated by the metal foil explosion.

[0021] In some embodiments, it also includes: an end plate that is in close contact with the outer surface of the positive and negative electrodes to prevent axial vibration when the pipe to be processed is deformed; and a fixing screw that axially penetrates the end plate to coaxially fix the pipe to be processed and the positive and negative electrodes.

[0022] A second aspect of this application relates to a method for electroexplosive forming or welding of tubular components based on a metal foil array, the method being applied to an apparatus as described in any embodiment of this application, comprising:

[0023] Place and fix component A and the pipe to be processed, so that the pipe to be processed is located between component A and the metal foil array, the metal foil array is in close contact with the surface of the pipe to be processed, each metal foil is equidistant from the pipe to be processed, and component A and the pipe to be processed are fixed in the axial direction;

[0024] A pulsed high voltage is simultaneously applied to multiple metal foils in a metal foil array by a pulsed power supply, so as to conduct the metal foils and generate a momentary pulsed large current.

[0025] Each metal foil undergoes a phase change at a preset explosion point, resulting in an electrical explosion, and an impact load is generated during the electrical explosion process.

[0026] Under the simultaneous action of multiple impact loads, multiple areas of the pipe to be processed undergo high-speed deformation and collide with component A, thereby achieving the forming or welding of the curved component. Component A is a forming mold or another pipe to be processed.

[0027] In some implementations, the amount of energy deposited before the metal foil explodes is altered by changing the magnitude and / or pulse width of the pulse current.

[0028] It is understandable that the beneficial effects of the second aspect can be found in the relevant descriptions in the first aspect above, and will not be repeated here.

[0029] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art:

[0030] This application proposes an apparatus for electro-explosive forming or welding of pipe fittings based on a metal foil array. The metal foil array consists of multiple metal foils uniformly distributed circumferentially. These foils undergo simultaneous phase transitions and generate shock waves upon the application of a pulsed current, driving deformation in the corresponding area of ​​the pipe fitting to be processed. By connecting the metal foil arrays in parallel, multiple foils simultaneously conduct and undergo phase transitions upon the application of a pulsed current, overcoming the limitation of traditional electro-explosive technology in applying to large-sized curved workpieces. An insulating positioning block controls the radial distance between the pipe fitting and the forming mold, better constraining the forming effect. For processing large workpieces, including but not limited to those with greater thickness, larger dimensions, and made of materials with higher yield strength, greater deposition energy is required. Therefore, a higher amplitude pulsed voltage needs to be applied through the power supply. However, existing electromagnetic forming devices using coil discharge suffer irreversible explosion failures due to the reduced coil lifespan after repeated applications of high-voltage pulses. This application uses a metal foil array as the electro-explosive material. Since metal foil is a disposable consumable, its raw materials are inexpensive, easy to process, and readily replaceable, thus negating the impact of multiple high-voltage pulses on the lifespan of the discharge device. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the metal foil electro-explosion diameter reduction forming apparatus provided in Embodiment 1 of this application.

[0032] Figure 2 This is a schematic diagram of the metal foil electro-explosion expansion forming device provided in Embodiment 2 of this application.

[0033] Figure 3 This is a schematic diagram of the metal foil explosion bidirectional drive welding device provided in Embodiment 3 of this application.

[0034] Figure 4 This is a schematic diagram of the metal foil structure provided in the embodiments of this application.

[0035] Figure 5 This is a schematic diagram of the metal foil array distribution provided in the embodiments of this application.

[0036] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0037] 1 is the pulse power supply system, 1-1 is the pulse capacitor, 1-2 is the line impedance, and 1-3 is the high-power switch; 2 is the impact load system: 2-1 is the electrode, 2-2 is the metal foil array, 2-3 is the forming mold, 2-4 is the support block, 2-5 is the insulating positioning block, and 2-6 is the upper and lower end plates; 2-7 is the fixing screw, 3 is the pipe to be processed, 3-1 is the first pipe to be processed, and 3-2 is the second pipe to be processed; 4 is the vacuum system, 4-1 is the vacuum gas duct, and 4-2 is the vacuum pump. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of 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 not intended to limit the scope of this application.

[0039] The embodiments of this application are described below with reference to the accompanying drawings.

[0040] This application proposes an apparatus and method for electro-explosive forming or welding of pipe fittings based on metal foil arrays. The purpose is to form pipe fittings or large curved workpieces that are difficult to solve by conventional electro-explosive methods, and to enhance energy utilization and improve forming quality by eliminating air resistance through vacuum.

[0041] In a first aspect, this application provides a method for electroexplosive forming or welding of tubular components based on a metal foil array, the method comprising the following steps:

[0042] (1) The pulse power supply simultaneously applies a high pulse voltage to multiple metal foils of the metal foil array through a single set of ring electrodes and generates a large pulse current;

[0043] (2) Each metal foil in the metal foil array undergoes phase changes such as solid, liquid, gas, and plasma transformation at multiple preset explosion points simultaneously, and generates an explosion shock wave load during the phase change process;

[0044] (3) The multi-point impact load generated by the metal foil array can act simultaneously on the pipe to be formed area, driving multiple areas of the pipe to undergo high-speed deformation and collision with the mold, thereby achieving the forming or welding effect of curved components.

[0045] Furthermore, by adjusting the magnitude of the pulse current, the energy deposited before the metal foil explodes can be controlled, thereby controlling the degree of plastic deformation of the pipe to be processed, thus achieving precise forming.

[0046] Furthermore, by adjusting the line impedance to control the time constant of the discharge circuit and thus adjusting the pulse width of the discharge current, the explosion time of the metal foil can be controlled, thereby regulating the deposition energy.

[0047] Furthermore, by flexibly adjusting circuit parameters such as line impedance by replacing the pulse capacitor and line impedance in the external pulse power supply system, the oscillation frequency, time constant, damping coefficient, peak value, and other characteristics of the discharge current can be changed, thereby altering the amount of energy deposited in the metal foil. The longer the current acts before the metal foil explodes, the larger the peak value and the greater the deposited energy, thus changing the forming effect of the pipe to be processed.

[0048] Secondly, this application provides a system for electro-explosive forming or welding of pipe fittings based on a metal foil array, comprising: a pulse power supply system, an impact load system, the pipe fitting to be processed, and a vacuum system.

[0049] The pulse power supply system, an external system, is connected to the device via power lines and is used to generate and regulate the pulse current discharging into the impact load system. It can modulate the discharge magnitude and pulse width to control the forming effect.

[0050] The pulse power supply system includes: a pulse capacitor, a high-power switch, and a line resistor; wherein, the pulse capacitor is connected in series in the line to store electrical energy and convert the 220V mains voltage into a pulse voltage, which is used to drive the impact load system. The discharge energy and discharge current pulse width can be adjusted by regulating the capacitance value of the capacitor; the high-power switch is connected in series in the line to control the discharge and ensure safe operation under the action of high pulse voltage; the line resistor is an inherent property of the line and is used to release electrical energy, causing charge to flow in the circuit, thereby generating current.

[0051] The impact load system is used to apply a large current from the pulse power supply system to the metal foil array and control the forming shape and position of the tube to be processed.

[0052] The impact load system includes: positive and negative electrodes, a metal foil array, a forming mold, a support block, an insulating positioning block, an end plate, and a fixing screw; the positive and negative electrodes are located at both ends of the metal foil array, and the two ends of the metal foil array are clamped by the annular electrode and the cylindrical insulating positioning block, and a pulse current is passed through the metal foil to drive the metal foil to explode electrically; the metal foil array is composed of multiple identical metal foils, which are evenly distributed circumferentially, so that they can undergo phase change simultaneously and generate shock waves after the pulse current is applied, thereby driving the deformation of the corresponding area of ​​the pipe to be processed; the forming mold is placed on the end plate. The deformation direction of the processed pipe fitting is used to control the curved shape of the pipe fitting; the support block is located outside the pipe fitting to be processed and the metal foil to prevent the leakage of shock waves generated by the explosion of the metal foil; the insulating positioning block is located between the electrode and the end of the pipe fitting to be processed to constrain the relative position of the pipe fitting to be processed and the forming mold, and to achieve electrical insulation between the electrode and the pipe fitting to be processed; the end plate is used to prevent unnecessary up-and-down shaking when the pipe fitting to be processed deforms; the fixing screw is used to achieve coaxial installation of the pipe fitting to be processed and the electrode, and to fix the end plate.

[0053] In forming applications where the tubing needs to contract inwards, the deformation of the tubing compresses the air inside, thus requiring a vacuum system to reduce the impact of air resistance. This vacuum system continuously creates a vacuum environment within the workpiece deformation space.

[0054] The vacuum system includes a vacuum tube and a vacuum pump; wherein the vacuum tube is used to connect the deformation space between the inside of the workpiece and the forming mold to the vacuum pump; and the vacuum pump is used to continuously create a vacuum environment for the workpiece deformation space.

[0055] Furthermore, the number of metal foils in the metal foil array can be adjusted according to the forming requirements of the pipe to be processed, so as to control the number of explosion points.

[0056] Furthermore, the shape of the metal foil can be adjusted. Depending on the needs of the explosion point, the metal foil can be cut to a specific size and placed inside the device before the test to regulate the force field distribution. The part that needs to be exploded can be cut into a narrow strip, and all cut parts can be rounded to improve the current distribution.

[0057] Furthermore, the shape of the electrode can be appropriately changed to supply power to different numbers of metal foils in parallel.

[0058] Furthermore, during device assembly, the relative inward and outward directions of the metal foil and the tube to be processed can be adjusted according to the tube forming requirements to achieve different functions.

[0059] Furthermore, the insulating positioning blocks are configured as stacked double cylindrical structures or cylindrical structures. During device assembly, by replacing insulating positioning blocks of different sizes, the distance between the pipe to be processed and the mold can be adjusted to change the collision speed and collision angle between the pipe and the mold.

[0060] Example 1

[0061] like Figure 1 As shown, the device includes a pulse capacitor 1-1, a line impedance 1-2, a high-power switch 1-3 (kilowatt level), an electrode 2-1, a metal foil 2-2, a forming mold 2-3, a support block 2-4, an insulating positioning block 2-5, upper and lower end plates 2-6, a fixing screw 2-7, a first tube to be processed 3-1, a vacuum gas guide tube 4-1, and a vacuum pump 4-2.

[0062] The forming mold 2-3 is placed inside the first tube to be processed 3-1. The metal foil 2-2 is arranged in an array around the outer surface of the tube. The position of the metal foil array is fixed by the support block 2-4. The electrode 2-1 is placed at the outer end of the tube and connected to the metal foil. The tube 3-1, the forming mold 2-3 and the electrode 2-1 are separated by the stepped insulating positioning block 2-5. The vacuum guide tube 4-1 is inserted into the workpiece deformation space at the center hole of the annular electrode and the insulating positioning block. The upper and lower end plates 2-6 are constrained by the fixing screw 2-7, thereby positioning the entire device. Finally, the vacuum pump 4-2 is turned on to continuously vacuum the entire deformation space.

[0063] The entire device is pre-treated with insulating tape, insulating positioning blocks, and insulating adhesive to prevent electrical conduction between possible metal conductors such as pipe 3-1 and support block 2-4. During the metal foil explosion, vacuum pump 4-2 continues to operate to maintain the air pressure around the workpiece at several thousand Pa or lower, keeping the workpiece deformation space in a vacuum environment.

[0064] The 220V AC mains power is stored in capacitor 1-1 in the power control system. When the voltage across the capacitor reaches the required voltage, the high-power switch 1-2 is closed to generate a pulse current that is passed through the electrodes into the metal foil array. This causes the narrowest part of all the metal foils 2-2 to undergo a phase change and explode simultaneously within 10 to 20 microseconds. The metal foil explosion can generate an instantaneous pressure of 1 GPa and a high-speed shock wave, which drives the tube to contract inward at a speed of more than 300 m / s. The tube deforms and collides with the internal forming mold 2-3 at high speed, causing the ductile tube to take the shape of the mold, thereby completing the diameter reduction forming.

[0065] Furthermore, by flexibly adjusting circuit parameters such as line impedance 1-2, the oscillation frequency, time constant, damping coefficient, and peak value of the discharge current can be changed, thereby altering the amount of energy deposited in the metal foil and thus changing the forming effect of the tube to be processed.

[0066] Furthermore, the shape of the metal foil 2-2 can be adjusted to regulate the force field distribution. The part that needs to be exploded is cut into a narrow strip, and all cut parts are rounded to improve the current distribution.

[0067] Furthermore, the insulating positioning blocks 2-5 can adjust the distance between the pipe and the forming mold, thereby adjusting the collision speed and angle when the workpiece collides with the mold. Generally, when the pipe is farther from the mold, the pipe accelerates for a longer time and collides with the mold at a faster speed, resulting in a better welding effect. However, a greater distance can lead to excessive deformation of the pipe and an excessively large collision angle with the mold. A near-perpendicular collision can make it difficult to form a welding interface, increasing the welding difficulty. Therefore, by adjusting the appropriate distance, the desired necking forming effect can be achieved.

[0068] Example 2

[0069] like Figure 2 As shown, the device includes a pulse capacitor 1-1, a line impedance 1-2, a high-power switch 1-3, an electrode 2-1, a metal foil 2-2, a forming mold 2-3, a support block 2-4, an insulating positioning block 2-5, upper and lower end plates 2-6, a fixing screw 2-7, and a first pipe to be processed 3-1.

[0070] The pulsed power supply system discharges to the metal foil 2-2 array. Under the action of the pulsed high current, the metal foil in the array undergoes a phase transition and generates an explosive shock wave, which in turn drives the first tube to be processed 3-1 to deform at high speed. Unlike Embodiment 1, in this embodiment, the metal foil array is located on the inner surface of the tube to be processed, and the forming mold is located on the outer surface of the tube to be processed. Therefore, under the action of the explosive shock wave, the tube to be processed will deform outward and fit tightly with the mold, achieving an expansion forming effect.

[0071] Similar to Example 1, the entire device is pre-treated with insulating means such as insulating tape, insulating positioning blocks, and insulating adhesive to prevent possible metal conductors such as pipes and support blocks from conducting electricity. Unlike Example 1, since the pipes do not compress air during outward expansion, vacuum treatment of the device is not required.

[0072] A pulsed current is generated by a power control system containing a capacitor bank and passed through electrodes into a metal foil array. This causes the narrowest part of all the metal foils to be plasmaized simultaneously within 10 to 20 microseconds, resulting in an explosion. The metal foil explosion can generate an instantaneous pressure of 1 GPa and a high-speed shock wave, driving the tube to deform at a speed of over 300 m / s towards the forming mold and collide with the mold. The collision causes the ductile tube to take the shape of the mold, thereby completing the expansion forming.

[0073] Furthermore, the insulating positioning block 2-5 is a cylinder with a diameter matching the inner diameter of the metal pipe, used to support the metal foil array on the inside and clamp it together with the first pipe to be processed.

[0074] When the forming mold 2-3 in Embodiment 1 and Embodiment 2 is replaced with the second pipe to be processed 3-2, this embodiment changes from a forming device to a unidirectional drive welding device, and the details will not be repeated here.

[0075] Example 3

[0076] like Figure 3 As shown, the device includes a pulse capacitor 1-1, a line impedance 1-2, a high-power switch 1-3, an electrode 2-1, a metal foil 2-2, a support block 2-4, an insulating positioning block 2-5, upper and lower end plates 2-6, a fixing screw 2-7, a first tube to be processed 3-1, a second tube to be processed 3-2, a vacuum gas guide tube 4-1, and a vacuum pump 4-2.

[0077] The second tube to be processed 3-2 is placed outside the first tube to be processed 3-1. Two sets of metal foil arrays are prepared, one set is wrapped around the outer surface of the second tube to be processed 3-2, and the other set is wrapped around the inner surface of the first tube to be processed 3-1. The position of the metal foil array is fixed by the support block 2-4. The electrode 2-1 is placed at the outer end of the tube and connected to the metal foil. The two tubes to be processed and the electrode 2-1 are separated by the stepped insulating positioning block 2-5. The vacuum guide tube 4-1 is extended into the workpiece deformation space. The upper and lower end plates 2-6 are constrained by the fixing screw 2-7, thereby positioning the entire device. Finally, the vacuum pump 4-2 is turned on to continuously vacuum the entire deformation space.

[0078] The structure of electrode 2-1 is specially treated so that it can supply power to two sets of metal foils at the same time and can cooperate with the insulating positioning block to simultaneously control the two sets of metal foil arrays to be tightly attached to the surface of the pipe to be processed.

[0079] Similar to Embodiments 1 and 2 above, the entire device is pre-treated with insulating methods such as insulating tape, insulating positioning blocks, and insulating adhesive to prevent conductive materials from possible metal conductors such as pipes and support blocks. A vacuum tube extends into the pipe, and a vacuum pump removes air from the device, creating a vacuum environment inside. Furthermore, during the metal foil explosion, the vacuum pump continues to operate to maintain a sufficiently low air pressure around the workpiece during the explosion, ensuring a vacuum environment inside the device.

[0080] A pulsed current is generated by a power control system containing a capacitor bank and passed through electrodes into a metal foil array. This causes the narrowest part of the inner and outer metal foils to be plasmaized simultaneously within 10 to 20 microseconds, resulting in an explosion. The metal foil explosion can generate an instantaneous pressure of 1 GPa and a high-speed shock wave, driving the inner and outer tubes to collide at a high speed of over 300 m / s. The enormous pressure and high-speed collision cause the ductile tubes to interact with each other, forming a welding interface, thus completing bidirectional drive welding.

[0081] Figure 4 This is a schematic diagram of the metal foil structure provided in an embodiment of this application. It typically consists of a rectangular metal foil strip with a thickness of less than 1 mm, with a relatively uniform, narrow section cut out at its waist. The purpose is to create a high-current-density, easily explosive region in the middle of the metal foil. The cut area is rounded to improve current distribution. After a pulsed high current is applied, the metal foil will preferentially explode in this region, forming a relatively regular shock wave shape. It should be noted that the shape of the metal foil in this application is not fixed; the specific length, thickness, and cut portion size can be adjusted as needed.

[0082] Figure 5 This is a schematic diagram of the metal foil array distribution provided in the embodiments of this application, which consists of... Figure 4 The metal foil structure shown is composed of a ring-shaped distribution. The size of the ring array is determined around the required pipe. The metal foils can be placed close together or spaced apart. The specific size of each metal foil and the number of metal foils required to form the array can be adjusted as needed. However, the size, shape, thickness and / or material of each metal foil are the same in order to control their explosion at close intervals as much as possible.

[0083] Compared with the prior art, this application has the following beneficial effects:

[0084] 1) This application provides a tube electro-explosion forming apparatus and method based on metal foil array, which realizes the forming of curved workpieces and larger tubes by multi-point explosion and multi-point deformation, and enhances the forming quality of the apparatus.

[0085] 2) This application provides a tube electro-explosive forming apparatus and method based on metal foil array, which forms the tube in the form of metal foil array. The shape of the metal foil and the number of metal foils in the array can be flexibly set according to the forming requirements to adjust the configuration of the impact load. It can be used with a variety of molds to expand its application range.

[0086] 3) This application provides a pipe fitting electro-explosive welding device and method based on metal foil array. Based on the forming device, this application can appropriately change the electrode shape and replace the mold with another pipe fitting. Under the action of the metal foil explosion shock wave, the pipe fitting is driven to deform at high speed and collide with each other to form a welding interface, thereby realizing high-speed impact welding between pipe fittings of different materials.

[0087] 4) This application provides an apparatus and method for electro-explosive forming or welding of pipe fittings based on a metal foil array in a vacuum. Sealing and vacuum treatment of the pipe fittings to be processed can reduce air resistance during the deformation process, improve energy utilization, and enhance forming or welding quality.

[0088] The aforementioned electro-explosive forming method and apparatus can not only achieve the forming or welding of tubular workpieces, but also effectively improve energy utilization and the forming or welding quality. It is of great significance for improving the electro-explosive forming processing system and expanding its application.

[0089] It should be understood that expressions such as “comprising” and “may include” used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0090] The terms "first" and "second," etc., used in the specification and claims of this application are used to distinguish different objects, not to describe a specific order of objects. For example, "first response message" and "second response message," etc., are used to distinguish different response messages, not to describe a specific order of response messages.

[0091] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0092] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple processing units means two or more processing units, multiple elements means two or more elements, etc.

[0093] Furthermore, in this application, the expression "and / or" includes any and all combinations of the associated listed words. For example, the expression "A and / or B" may include A, may include B, or may include both A and B.

[0094] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after connection. "Rotary connection" refers to a connection where the components can rotate relative to each other after connection. "Sliding connection" refers to a connection where the components can slide relative to each other after connection. The directional terms mentioned in the embodiments of this application, such as "top," "bottom," "inner," "outer," "left," and "right," are only for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of this application, and are not intended to indicate or imply that the device or component 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 the embodiments of this application.

[0095] Furthermore, the mathematical concepts mentioned in the embodiments of this application, such as symmetry, equality, parallelism, and perpendicularity, are limitations specific to the current technological level, rather than absolute and strict mathematical definitions. Slight deviations are permissible; approximations of symmetry, equality, parallelism, and perpendicularity are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 and 10 degrees. "A and B are perpendicular" means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0096] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An apparatus for electroexplosive forming or welding of tubular fittings based on a metal foil array, characterized in that, include: The metal foil array consists of multiple metal foils that are evenly distributed circumferentially. It is used to generate multi-point shock waves by simultaneously causing phase transitions at multiple preset explosion points after a pulse current is applied, thereby driving deformation of the corresponding area of ​​the first pipe to be processed. The electrodes located at both ends of the metal foil array are used to connect to a pulse power supply to supply power to each metal foil in parallel. The end plate, which is in close contact with the outer surface of the electrode, is used to prevent axial vibration when the first tube to be processed deforms. A fixing screw that penetrates the end plate axially is used to coaxially fix the first pipe to be processed and the electrode; An insulating positioning block, closely attached to the inner surface of the electrode, is used to insulatingly separate the first tube to be processed, component A, and the electrode. Component A is a forming mold or a second tube to be processed. The block constrains the radial relative position of the metal foil array, the first tube to be processed, and component A, such that component A is placed in the deformation direction of the first tube to be processed, and the metal foil array is located in the opposite direction of the deformation of the first tube to be processed. The two ends of the metal foil array are radially fixed, and the two ends of the first tube to be processed are axially closed, so that the workpiece deformation space between the insulating positioning block and the first tube to be processed is sealed. The electrode is a ring electrode, which cooperates with the insulating positioning block to radially press the edges of both ends of the metal foil array.

2. The apparatus as claimed in claim 1, characterized in that, The metal foil array is replaceable, and the number and / or position of the metal foils in the array can be adjusted according to the forming requirements to adapt to different molds; the size, shape, thickness and / or material of each metal foil are the same and can be adjusted according to the forming requirements to adjust the magnitude of the impact load.

3. The apparatus as described in claim 2, characterized in that, The height of the preset explosion points of each metal foil may be the same or different. The preset explosion point is the narrowest position on the cut metal foil, and the height value is adjusted according to the forming requirements to adapt to different molds.

4. The apparatus as claimed in claim 1, characterized in that, When component A is placed inside the first pipe to be processed, the insulating positioning block is a double cylindrical structure with a T-shaped cross-section. The top width of the double cylindrical structure with a T-shaped cross-section matches the diameter of the metal foil, and the bottom width matches the inner diameter of the first pipe to be processed.

5. The apparatus according to any one of claims 1 to 4, characterized in that, Also includes: The vacuum tube extending from the center hole of the electrode is used to connect the workpiece deformation space and the vacuum pump; the vacuum pump is used to continuously vacuum the entire workpiece deformation space to maintain the air pressure in the workpiece deformation direction environment not exceeding 10 kPa during the explosion.

6. The apparatus according to any one of claims 1 to 4, characterized in that, Also includes: Support blocks surrounding the outer surface of the metal foil array are used to prevent leakage of shock waves generated by the explosion of the metal foil.

7. A method for electroexplosive forming or welding of tubular fittings based on a metal foil array, characterized in that, The method is applied to the apparatus as described in any one of claims 1 to 6, comprising: Place and fix component A and the first tube to be processed, such that the first tube to be processed is located between component A and the metal foil array, the metal foil array is in close contact with the surface of the first tube to be processed, each metal foil is equidistant from the radial distance of the first tube to be processed, and component A and the first tube to be processed are fixed in the axial direction. A pulsed high voltage is simultaneously applied to multiple metal foils in a metal foil array by a pulsed power supply, so as to conduct the metal foils and generate a momentary pulsed large current. Each metal foil undergoes a phase change at a preset explosion point, resulting in an electrical explosion, and an impact load is generated during the electrical explosion process. Under the simultaneous action of multiple impact loads, multiple areas of the first pipe to be processed undergo high-speed deformation and collide with component A, thereby realizing the forming or welding of the curved component. Component A is a forming mold or the second pipe to be processed.

8. The method as described in claim 7, characterized in that, The amount of energy deposited before the metal foil explodes can be altered by changing the magnitude and / or pulse width of the pulse current.

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