Device and method for electric explosion forming or welding of pipe fitting based on metal foil array

Abstract

The invention belongs to the field of pipe fitting forming and manufacturing, and particularly discloses a device and method for pipe fitting electric explosion forming or welding based on a metal foil array. According to the metal foil array, the metal foil array is composed of the multiple metal foils, and the multiple metal foils are evenly distributed in the circumferential direction and used for conducting phase change and generating shock waves at the same time after the pulse current is input so as to drive the corresponding area of the to-be-machined pipe fitting to deform. The metal foil arrays are connected in parallel, the multiple metal foils are conducted and subjected to phase change at the same time after pulse current is introduced, and the defect that a traditional electric explosion technology cannot be applied to large-size curved-surface workpieces is overcome. The radial distance between the pipe fitting and the forming die is controlled through the insulating positioning block, so that the forming effect is better restrained. The metal foil array is used as an electric explosion material, the metal foil belongs to a disposable consumable, and the raw material is low in price, easy to process and convenient to replace, so that the influence of multiple pulse high voltages on the service life of the discharge device can be ignored.

Description

Technical Field

[0001] The present application belongs to the field of pipe forming and manufacturing, and more specifically, to a device and method for electroexplosive forming or welding of pipes based on metal foil arrays. Background Art

[0002] High-rate forming is a processing technology that uses high-density energy, such as explosion shock waves and pulsed electromagnetic forces, as impact loads. As a newly proposed high-speed forming technology, metal foil electric explosion forming technology has the advantages of low cost, high efficiency, high controllability and easy automation. Its main principle is to load a pulsed high voltage on the metal foil to make it undergo six phase change stages: solid heating, liquefaction, liquid heating, gasification, breakdown ionization, and plasma evolution. During the phase change process, the generated gasification shock wave and plasma shock wave act on the workpiece, driving the workpiece to be formed to deform and collide with the mold at high speed, and fit with the mold, and finally process the workpiece into the desired shape. The electric explosion device is relatively simple and low-cost. No heating or continuous friction is required during the forming process, and no heat-affected zone is formed. The formation of intermetallic compounds can be minimized. It has high practical application value and can be promoted on a large scale.

[0003] At present, the metal foil electric explosion forming technology has been initially applied to the processing and forming of two-dimensional planar components of plates. However, limited by the basic principle of electric explosion, this method faces challenges in the processing of curved components: First, the smooth progress of electric explosion is inseparable from the formation of plasma channels and the accumulation of deposition energy. However, the existing electric explosion technology is difficult to effectively form a plasma channel with controllable length and curvature on the surface of curved workpieces. The uncontrollable formation of plasma channels is specifically reflected in the uncertainty of the explosion point and explosion time. The former makes it difficult to ensure the action area and forming accuracy of the explosive force load, and the latter makes it difficult to effectively accumulate deposition energy and the forming degree is difficult to achieve the expected degree; in addition, there are some other problems, such as the relatively concentrated impact force of the electric explosion of a single metal foil, resulting in a small deformation area of ​​the processed workpiece, and multiple processing is required in the process of forming large-size pipes, which is more complicated to operate; for example, for workpieces with a relatively closed processing area, such as long pipes that shrink inward, at the moment of electric explosion deformation, the air between the workpiece and the mold or other workpieces is difficult to discharge, the deformation will compress the air, and the air resistance will consume the explosion energy and weaken the forming effect. Patent CN113458234A discloses a device and method for forming a workpiece by using a metal foil electric explosion shock wave. The metal foil is passed through a pulse power supply system and a pulse current is passed through the metal foil. The metal foil explodes under the action of the pulse current to generate a violent shock wave. During the explosion of the metal foil, a redox reaction occurs with the liquid in the liquid environment to release a large amount of energy. Under the action of the shock wave and energy, the metal workpiece to be processed produces a mechanical response and is processed and formed. However, it has the following defects and shortcomings: 1) The electro-hydraulic explosion must immerse the entire device, especially the metal foil, in a water environment, and cannot be applied to workpieces that are not suitable for immersion in water. Moreover, under the action of a higher current, many metal workpieces will react chemically with water to generate byproducts that damage the strength of the workpiece; 2) The electro-hydraulic explosion uses a uniform metal foil with no obvious weak points in the structure. Under the action of the pulse current, the metal foil may explode at any position, resulting in a random position of the explosion impact force loading, which greatly affects the forming accuracy; 3) Due to the properties of the electro-hydraulic fluid, any shock wave generated by the electric explosion will be transformed into a spherical shock wave under the constraint of the liquid, so this technology can only perform spherical forming on the workpiece.

[0004] In summary, the electro-explosive forming technology for large axisymmetric curved workpieces, especially pipe fittings, needs to be developed. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of the present application is to provide an apparatus and method for electro-explosive forming or welding of pipes based on a metal foil array, aiming to solve the problem that traditional electro-explosive technology cannot be applied to large-sized curved workpieces.

[0006] The first aspect of the present application relates to a device for electroexplosive forming or welding of a tube based on a metal foil array, the device comprising: The metal foil array is composed of a plurality of metal foils, which are evenly distributed along the circumference and are used to simultaneously undergo phase change and generate shock waves after a pulse current is passed through, so as to drive the corresponding area of ​​the pipe to be processed to deform; The positive and negative 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 insulating positioning block, which is close to the inner surface of the positive and negative electrodes, is used to insulate and separate the pipe to be processed, component A and the electrode, wherein 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, so 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 deformation space of the workpiece between the insulating positioning block and the pipe to be processed is sealed.

[0007] In some embodiments, the metal foil array supports replacement, and the number and / or position of the metal foils in the array are adjusted according to the 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 the forming requirements to adjust the size of the impact load.

[0008] It should be noted that the size, shape, thickness and material of the metal foil in the metal foil array are all adjustable, which affects the amount of deposited energy, thereby realizing the loading and regulation of the impact force load to achieve the desired forming effect.

[0009] In some embodiments, the heights of the preset explosion sites of the metal foils are the same or different. The preset explosion sites are the narrowest positions on the metal foils after cutting. The height values ​​are adjusted according to forming requirements to adapt to different molds.

[0010] It should be noted that the number of metal foils in the metal foil array, the height of the cutting part, and the position of the metal foil are all adjustable, so as to adapt to more molds and process the workpiece into more shapes; the part of the metal foil that needs to be exploded is cut into uniform narrow strips without sharp corners, and the current density at the narrowest part is higher, so as to customize the weak point of the metal foil and better control the explosion position, thereby allowing the workpiece to deform at a specific point; compared with the high-speed effect of the current, the difference in explosion time caused by the height difference can be ignored, and it can still be regarded as a simultaneous explosion; In some embodiments, the heights of the preset explosion sites of the metal foils are the same or different, and the preset explosion sites are the narrowest positions on the metal foils after cutting.

[0011] 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 matches the diameter of the metal foil, and the bottom width matches 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, and its diameter matches the inner diameter of the pipe to be processed.

[0012] 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.

[0013] It should be noted that the present application preferably uses annular electrodes to load current on different numbers of metal foils so as to cooperate with more complex molds to achieve multi-point forming.

[0014] In some embodiments, it also includes: a vacuum tube extending from the center hole of the electrode, used to connect the workpiece deformation space with a vacuum pump; a vacuum pump, used to continuously vacuum the entire workpiece deformation space to maintain the air pressure in the workpiece deformation direction during the explosion at a level not exceeding 10 kPa.

[0015] It should be noted that the present application optimizes the rebound problem of internal air when performing diameter reduction forming on devices containing air such as metal pipes with closed ends, etc., by adding a vacuum tube channel to continuously evacuate the deformation space of the workpiece, thereby improving energy utilization and improving the forming or welding quality.

[0016] In some embodiments, the invention further comprises: a support block surrounding the outer surface of the metal foil array, for preventing the leakage of shock waves generated by the explosion of the metal foil.

[0017] In some embodiments, it also includes: an end plate that is in close contact with the outer surfaces of the positive and negative electrodes, which is used to prevent axial shaking when the pipe to be processed is deformed; a fixing screw that axially penetrates the end plate, which is used to coaxially fix the pipe to be processed and the positive and negative electrodes.

[0018] The second aspect of the present application relates to a method for electroexplosive forming or welding of a tube based on a metal foil array, the method being applied to a device as in any one embodiment of the present application, comprising: Insert 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 close to the surface of the pipe to be processed, the radial distance between each metal foil and the pipe to be processed is equal, and component A and the pipe to be processed are fixed in the axial direction; A pulse high voltage is simultaneously applied to multiple metal foils of the metal foil array by a pulse power supply to conduct the metal foils to generate an instantaneous pulse large current; Each metal foil undergoes phase change at the preset explosion point simultaneously, and then undergoes electrical explosion, and generates impact load during the electrical explosion process; Under the simultaneous action of multi-point impact loads, multiple areas of the pipe to be processed are deformed at high speed and collide with component A, thereby realizing the forming or welding of the curved surface component, wherein component A is a forming mold or another pipe to be processed.

[0019] In some embodiments, the energy deposited before the metal foil explodes is changed by changing the magnitude and / or pulse width of the pulse current.

[0020] It can be understood that the beneficial effects of the second aspect can be found in the relevant description of the first aspect above, and will not be repeated here.

[0021] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art: The present application proposes a device for electro-explosive forming or welding of pipe fittings based on a metal foil array, wherein the metal foil array is composed of a plurality of metal foils, which are evenly distributed along the circumference and are used to simultaneously undergo phase change and generate shock waves after a pulse current is passed through, so as to drive the deformation of the corresponding area of ​​the pipe fitting to be processed. By connecting the metal foil array in parallel, the plurality of metal foils are simultaneously turned on and undergo phase change after a pulse current is passed through, which solves the defect that the traditional electro-explosive technology cannot be applied to large-sized curved surface workpieces; the radial distance between the pipe fitting and the forming die is controlled by the insulating positioning block to better constrain the forming effect. In the face of the processing of large workpieces, including but not limited to thicker thickness, larger size, and made of higher yield strength materials, the required deposition energy is greater, therefore, it is necessary to load a pulse voltage with a higher amplitude through a power supply, however, the existing electromagnetic forming device using coil discharge will be affected by the life of the coil after multiple pulse high voltages are passed through, and an irreversible explosion failure will eventually occur. In this regard, the present application uses a metal foil array as an electro-explosive material, and the metal foil is a disposable consumable, and its raw material price is low, and it is easy to process and replace, so that the influence of multiple pulse high voltages on the life of the discharge device can be ignored. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the metal foil electric explosion shrinking forming device provided in Example 1 of the present application.

[0023] Figure 2 It is a schematic diagram of the metal foil electric explosion expansion forming device provided in Example 2 of the present application.

[0024] Figure 3 It is a schematic diagram of the metal foil explosion bidirectional drive welding device provided in Example 3 of the present application.

[0025] Figure 4 It is a schematic diagram of the metal foil structure provided in the embodiment of the present application.

[0026] Figure 5It is a schematic diagram of the distribution of the metal foil array provided in the embodiment of the present application.

[0027] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1 is a pulse power supply system, 1-1 is a pulse capacitor, 1-2 is a line impedance, and 1-3 is a high-power switch; 2 is an impact load system: 2-1 is an electrode, 2-2 is a metal foil array, 2-3 is a forming mold, 2-4 is a support block, 2-5 is an insulating positioning block, and 2-6 are upper and lower end plates; 2-7 is a fixing screw, 3 is a pipe to be processed, 3-1 is a first pipe to be processed, and 3-2 is a second pipe to be processed; 4 is a vacuum system, 4-1 is a vacuum air guide tube, and 4-2 is a vacuum pump. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0030] The present application proposes an apparatus and method for electro-explosive forming or welding of pipes based on a metal foil array, the purpose of which is to form pipes or large curved workpieces that are difficult to form using conventional electro-explosive methods, and to enhance energy utilization and improve forming quality by eliminating air resistance through vacuum.

[0031] In a first aspect, the present application provides a method for electro-explosive forming or welding of a tube based on a metal foil array, the method comprising the following steps: (1) The pulse power supply simultaneously applies a pulse high voltage to multiple metal foils of the metal foil array through a single set of annular electrodes, thereby generating a pulse high current; (2) Each metal foil in the metal foil array undergoes phase changes such as solid, liquid, gas, and plasma at multiple preset explosion points simultaneously, and generates explosion shock wave loads during the phase change process; (3) The multi-point impact load generated by the metal foil array can act on the area to be formed of the pipe at the same time, driving multiple areas of the pipe to deform and collide with the mold at high speed, thereby achieving the forming or welding effect of the curved surface component.

[0032] 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, thereby achieving precise forming.

[0033] Furthermore, by adjusting the line impedance to control the time constant of the discharge loop 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.

[0034] Furthermore, by replacing the pulse capacitor and line impedance in the external pulse power supply system and flexibly adjusting circuit parameters such as line impedance, the oscillation frequency, time constant, damping coefficient, peak value and other characteristics of the discharge current can be changed, thereby changing the amount of deposited energy in the metal foil. The longer the current action time before the metal foil explodes, the larger the peak value and the greater the deposited energy, thereby changing the forming effect of the pipe to be processed.

[0035] In a second aspect, the present application provides a system for electroexplosive forming or welding of pipes based on a metal foil array, comprising: a pulse power supply system, an impact load system, a pipe to be processed, and a vacuum system.

[0036] Pulse power supply system: The pulse power supply system is an external system that is connected to the device through a transmission line and is used to generate and adjust the pulse current discharged to the impact load system. It can modulate the discharge size and pulse width to achieve the control of the forming effect.

[0037] 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 electric energy and convert the city voltage of 220 volts into a pulse voltage, and the pulse voltage is used to drive the impact load system. The discharge energy and the 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 the pulse high voltage; the line resistor is an inherent property of the line, and is used to release electric energy, so that the charge in the circuit flows, thereby generating current.

[0038] The impact load system is used to load a large current from a pulse power supply system into the metal foil array and control the forming shape and position of the pipe to be processed.

[0039] The impact load system comprises: positive and negative electrodes, a metal foil array, a forming die, 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 an annular electrode and a cylindrical insulating positioning block, and a pulse current is passed through the metal foil to drive the metal foil to explode; the metal foil array is composed of a plurality of identical metal foils, and the plurality of metal foils are evenly distributed along the circumference, and are used to simultaneously undergo phase change and generate shock waves after the pulse current is passed, so as to drive the deformation of the corresponding area of ​​the pipe to be processed; the forming die is placed on the pipe to be processed The deformation direction of the processed pipe is used to adjust the curved surface forming shape of the pipe; the support block is located outside the pipe to be processed and the metal foil, and is used to prevent the shock wave generated by the explosion of the metal foil from leaking; the insulating positioning block is located between the electrode and the end of the pipe to be processed, and is used to constrain the relative position of the pipe to be processed and the forming mold, and to achieve electrical insulation between the electrode and the pipe to be processed; the end plate is used to prevent unnecessary up and down shaking of the pipe to be processed when it is deformed; the fixing screw is used to achieve coaxial installation of the pipe to be processed and the electrode, and to fix the end plate.

[0040] In forming applications where the pipe is required to shrink inward, the deformation of the pipe will compress the air inside it, so a vacuum system is needed to reduce the impact of air resistance. The vacuum system is used to continuously create a vacuum environment for the deformation space of the workpiece.

[0041] 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 and the vacuum pump; the vacuum pump is used to continuously create a vacuum environment for the deformation space of the workpiece.

[0042] 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 to control the number of explosion points.

[0043] Furthermore, the shape of the metal foil can be adjusted. According to the needs of the explosion point, the metal foil can be cut into specific sizes and placed in the device before the test to regulate the force field distribution. The part that needs to be exploded can be cut into narrow strips, and all cut places can be rounded to improve current distribution.

[0044] Furthermore, the shape of the electrode can be appropriately changed to supply power to different numbers of metal foils in parallel.

[0045] Furthermore, when the device is assembled, the relative inner and outer directions of the metal foil and the pipe to be processed can be adjusted according to the forming requirements of the pipe to achieve different functions.

[0046] Furthermore, the insulating positioning block is configured as a stacked double cylindrical structure or a cylindrical structure. When the device is assembled, the distance between the pipe to be processed and the mold can be adjusted by replacing insulating positioning blocks of different sizes to change the collision speed and collision angle between the pipe and the mold.

[0047] Example 1 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 pipe to be processed 3-1, a vacuum air guide tube 4-1 and a vacuum pump 4-2.

[0048] The forming mold 2-3 is placed inside the first pipe 3-1 to be processed, and the metal foil 2-2 is arrayed around the outer surface of the pipe. The position of the metal foil array is fixed by the support block 2-4. The electrode 2-1 is placed on the outer end of the pipe and connected to the metal foil. The pipe 3-1, the forming mold 2-3 and the electrode 2-1 are separated by the stepped insulating positioning block 2-5. The vacuum air guide tube 4-1 is extended into the deformation space of the workpiece 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, and then the entire device is positioned. Finally, the vacuum pump 4-2 is turned on to continuously vacuum the entire deformation space.

[0049] The entire device is pre-treated with insulating means such as insulating tape, insulating positioning blocks, and insulating glue to prevent mutual conduction between possible metal conductors such as pipe 3-1 and support blocks 2-4. During the explosion of the metal foil, the vacuum pump 4-2 continues to work to maintain the air pressure around the workpiece at several thousand Pa or lower during the explosion, so that the deformation space of the workpiece is in a vacuum environment.

[0050] The 220V mains electricity is stored through the 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 electrode into the metal foil array, causing the narrowest parts of all metal foils 2-2 to simultaneously change phase within 10 to 20 microseconds and then explode. The metal foil explosion can generate an instantaneous pressure of 1GPa and a high-speed shock wave, driving the pipe to shrink inward at a speed of more than 300m / s, deforming at high speed in the direction of the internal forming mold 2-3 and colliding with the mold, so that the ductile pipe becomes the shape of the mold, thereby completing the diameter reduction forming.

[0051] Furthermore, by flexibly adjusting circuit parameters such as line impedance 1-2, the oscillation frequency, time constant, damping coefficient, peak value and other characteristics of the discharge current can be changed, thereby changing the amount of energy deposited in the metal foil and further changing the forming effect of the pipe to be processed.

[0052] Furthermore, the shape of the metal foil 2-2 can be adjusted to control the force field distribution, and the portion to be exploded can be cut into narrow strips, and all cut portions can be rounded to improve current distribution.

[0053] Furthermore, the insulating positioning blocks 2-5 can adjust the distance between the pipe and the forming die, and then adjust the collision speed and collision angle when the workpiece collides with the die. Generally, when the pipe is far away from the die, the pipe acceleration time is long, the speed when colliding with the die is faster, and the welding effect is better. However, a long distance will cause the pipe to deform too much, and the collision angle with the die is too large. A collision close to vertical will make it difficult to form a welding interface, increasing the difficulty of welding. Therefore, by adjusting the appropriate distance, the expected necking forming effect can be achieved.

[0054] Example 2 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.

[0055] The pulse power system discharges to the metal foil 2-2 array, and the metal foil in the array undergoes a phase change under the action of the pulsed large current, and generates an explosion shock wave, thereby driving the first pipe 3-1 to be processed to deform at a high speed. Different from the first embodiment, in this embodiment, the metal foil array is located on the inner surface of the pipe to be processed, and the forming mold is located on the outer surface of the pipe to be processed. Therefore, under the action of the explosion shock wave, the pipe to be processed will deform outward and fit tightly with the mold to achieve a bulging forming effect.

[0056] As in Example 1, the entire device is pre-treated with insulating means such as insulating tape, insulating positioning blocks, and insulating glue to prevent possible metal conductors such as pipes and support blocks from conducting electricity. Unlike Example 1, since the air will not be compressed during the outward expansion of the pipe, the device does not need to be vacuum treated.

[0057] A pulse current is generated by a power control system including a capacitor group and passed through electrodes into the metal foil array, causing the narrowest parts of all the metal foils to be simultaneously plasmatized within 10 to 20 microseconds and then explode. The metal foil explosion can generate an instantaneous pressure of 1 GPa and a high-speed shock wave, driving the pipe to deform at a high speed in the direction of the forming mold at a speed of more than 300 m / s and collide with the mold. The collision will cause the ductile pipe to become the shape of the mold, thereby completing the expansion forming.

[0058] Furthermore, the insulating positioning block 2-5 is a cylinder whose diameter matches the inner diameter of the metal pipe, and is used to support the metal foil array on the inner side and clamp it together with the first pipe to be processed.

[0059] When the forming mold 2-3 in Example 1 and Example 2 is replaced by the second pipe 3-2 to be processed, the embodiment is changed from a forming device to a one-way drive welding device, and the details are not repeated here.

[0060] Example 3 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 pipe to be processed 3-1, a second pipe to be processed 3-2, a vacuum air guide tube 4-1 and a vacuum pump 4-2.

[0061] The second pipe to be processed 3-2 is placed outside the first pipe to be processed 3-1, and two sets of metal foil arrays are prepared, one of which surrounds the outer surface of the second pipe to be processed 3-2, and the other surrounds the inner surface of the first pipe to be processed 3-1. The position of the metal foil array is fixed by the support block 2-4, and the electrode 2-1 is placed on the outer end of the pipe and connected to the metal foil. The two pipes to be processed and the electrode 2-1 are separated by a stepped insulating positioning block 2-5, and the vacuum air guide tube 4-1 is extended into the deformation space of the workpiece. The upper and lower end plates 2-6 are constrained by the fixing screw 2-7, and the entire device is positioned. Finally, the vacuum pump 4-2 is turned on to continuously vacuum the entire deformation space.

[0062] The structure of electrode 2-1 is specially processed 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 close to the surface of the pipe to be processed.

[0063] Similar to the first and second embodiments, the entire device is pre-treated with insulating means such as insulating tape, insulating positioning blocks, and insulating glue to prevent possible metal conductors such as pipes and support blocks from conducting electricity. The vacuum tube extends into the pipe, and the air in the device is pumped out by the vacuum pump to create a vacuum environment inside the device. And during the metal foil explosion process, the vacuum pump continues to work to maintain a sufficiently low air pressure around the workpiece during the explosion, so that the inside of the device is in a vacuum environment.

[0064] A pulse current is generated by a power control system including a capacitor group and passed through electrodes into the metal foil array, causing the narrowest parts of the inner and outer metal foils to simultaneously plasmatize and explode within 10 to 20 microseconds. The metal foil explosion can generate an instantaneous pressure of 1GPa and a high-speed shock wave, driving the inner and outer pipes to collide with each other at a speed of more than 300m / s. The huge pressure and high-speed collision will cause the ductile pipes to interact with each other, forming a welding interface, thereby completing two-way drive welding.

[0065] Figure 4 This is a schematic diagram of the metal foil structure provided in the embodiment of the present application. It is usually composed of a rectangular metal foil strip with a thickness of less than 1 mm, with a relatively uniform narrow area cut out at its waist. The purpose is to form an explosion-prone area with a higher current density in the middle part of the metal foil, and to round the corners of the cut area to improve the current distribution. After a high pulse current is passed through, the metal foil will explode preferentially in this area and form a more regular shock wave shape. It should be noted that the shape of the metal foil in this application is not fixed, and the specific length, thickness, and size of the cut portion can be adjusted as needed.

[0066] Figure 5 is a schematic diagram of the distribution of the metal foil array provided in the embodiment of the present application, which consists of Figure 4 The metal foil structure shown is composed of a ring distribution, and the size of the ring array is determined around the required pipe. The metal foils can be placed close to each other or at intervals. The specific size of each metal foil and the number of metal foils required to form the array can be adjusted as needed, but the size, shape, thickness and / or material of each metal foil are the same to try to control their explosion at a close time.

[0067] Compared with the prior art, this application has the following beneficial effects: 1) The present application provides a device and method for electro-explosive forming of pipes based on a metal foil array, which realizes the forming of curved workpieces and larger pipes by means of multi-point explosion and multi-point deformation, and enhances the forming quality of the device.

[0068] 2) The present application provides a device and method for electro-explosive forming of pipe fittings based on a metal foil array, which realizes the forming of pipe fittings in the form of a 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 position of the impact load, and can be cooperated with a variety of molds to expand its scope of application.

[0069] 3) The present application provides a device and method for electric explosion welding of pipe fittings based on a metal foil array. On the basis of the forming device, the present 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 fittings can be 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 dissimilar materials.

[0070] 4) The present application provides a device and method for electro-explosive forming or welding of pipes based on a metal foil array in a vacuum. Sealing and vacuum treatment of the pipes to be processed can reduce air resistance during the deformation of the pipes, improve energy utilization, and enhance forming or welding quality.

[0071] The above-mentioned electric explosive forming method and device can not only realize the forming or welding of tubular workpieces, but also effectively improve energy utilization and improve forming or welding quality, which is of great significance for improving the electric explosive forming processing system and expanding its application.

[0072] It should be understood that expressions such as "including" and "may include" that may be used in the present 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 the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0073] The terms "first" and "second" in the specification and claims of this application are used to distinguish different objects rather than to describe a specific order of objects. For example, a first response message and a second response message are used to distinguish different response messages rather than to describe a specific order of response messages.

[0074] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0075] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0076] In addition, in the present 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.

[0077] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. 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. Among them, "fixed connection" means that the relative position relationship after connection remains unchanged. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after connection. The directional terms mentioned in the embodiments of the present application, such as "top", "bottom", "inside", "outside", "left", "right", etc., are only reference directions of the accompanying drawings. Therefore, the directional terms used are for better and clearer explanation and understanding of the embodiments of the present application, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0078] In addition, in the embodiments of the present application, the mathematical concepts mentioned are symmetry, equality, parallelism, verticality, etc. These limitations are all for the current state of the art, rather than being absolutely strict definitions in a mathematical sense, and allow a small amount of deviation, approximation to symmetry, approximation to equality, approximation to parallelism, approximation to verticality, etc. are all possible. For example, A and B are parallel, which 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, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 and 100 degrees.

[0079] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A device for electro-explosive forming or welding of tubes based on a metal foil array, characterized in that: include: The metal foil array is composed of multiple metal foils, which are evenly distributed along the circumference and are used to simultaneously undergo phase change and generate shock waves when a pulse current is passed through, thereby driving the deformation of the corresponding area of ​​the pipe to be processed; The positive and negative 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 insulating positioning blocks, which are in close contact with the inner surfaces of the positive and negative electrodes, are used to insulate and separate the pipe to be processed, component A and the electrodes. The 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 so 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 deformation space of the workpiece between the insulating positioning block and the pipe to be processed is sealed.

2. The device according to claim 1, wherein The metal foil array supports replacement, and the number and / or position of the metal foils in the array are 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 device according to claim 2, wherein The height of the preset explosion site of each metal foil is the same or different. The preset explosion site is the narrowest position on the metal foil after cutting. The height value is adjusted according to the forming requirements to adapt to different molds.

4. The device according to claim 1, wherein 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 matches the diameter of the metal foil, and the bottom width matches 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, and its diameter matches the inner diameter of the pipe to be processed.

5. The device according to claim 1, wherein The electrode is a ring electrode and cooperates with the insulating positioning block to radially press the edges of both ends of the metal foil array.

6. The device according to any one of claims 1 to 5, characterized in that Also includes: The vacuum tube extending from the center hole of the electrode is used to connect the workpiece deformation space with the vacuum pump; the vacuum pump is used to continuously vacuum the entire workpiece deformation space to maintain the air pressure in the environment in the direction of workpiece deformation during explosion at no more than 10kPa.

7. The device according to any one of claims 1 to 5, characterized in that Also includes: The support blocks surrounding the outer surface of the metal foil array are used to prevent the leakage of shock waves generated by the metal foil explosion.

8. The device according to any one of claims 1 to 5, characterized in that Also includes: The end plates that are in close contact with the outer surfaces of the positive and negative electrodes are used to prevent axial shaking when the pipe to be processed is deformed; the fixing screws that axially penetrate the end plates are used to coaxially fix the pipe to be processed and the positive and negative electrodes.

9. A method for electro-explosive forming or welding of tubes based on a metal foil array, characterized in that: The method is applied to the device according to any one of claims 1 to 8, comprising: Place and secure 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, the radial distance between each metal foil and the pipe to be processed is equal, and component A and the pipe to be processed are fixed in the axial direction; A pulse high voltage is simultaneously applied to multiple metal foils of the metal foil array through a pulse power supply to conduct the metal foils to generate an instantaneous pulse high current; Each metal foil undergoes phase change at the preset explosion point simultaneously, and then an electric explosion occurs, and an impact load is generated during the electric explosion process; Under the simultaneous action of multi-point impact loads, multiple areas of the pipe to be processed deform at high speed and collide with component A, thereby realizing the forming or welding of the curved surface component, wherein component A is a forming mold or another pipe to be processed.

10. The method according to claim 9, wherein By changing the magnitude and / or pulse width of the pulse current, the magnitude of the energy deposited before the metal foil explodes can be changed.

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