CN-119657739-B - Device and method for electro-explosive forming or welding of pipe fittings based on metal foil array

CN119657739BCN 119657739 BCN119657739 BCN 119657739BCN-119657739-B

Abstract

The application belongs to the field of pipe fitting forming and manufacturing, and particularly discloses a device and a method for pipe fitting electric explosion forming or welding based on a metal foil array. According to the application, the metal foil array is composed of a plurality of metal foils, and the plurality of metal foils are uniformly distributed along the circumferential direction and are used for simultaneously generating phase change and shock waves after pulse current is introduced so as to drive the corresponding area of the pipe fitting to be processed to deform. The metal foil arrays are connected in parallel, and the metal foils are simultaneously conducted and subjected to phase change after pulse current is introduced, so that the defect that the traditional electric explosion technology cannot be applied to large-size curved surface workpieces is overcome, and 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 application adopts the metal foil array as the electric explosion material, the metal foil belongs to disposable consumable materials, the raw materials are low in price, and the metal foil is easy to process and convenient to replace, so that the influence of the high voltage of the multiple pulses on the service life of the discharge device can be ignored.

Inventors

LI XIAOXIANG
LI MENGXIAN
TUO ZHAN
TANG XINYU
GONG MENGYUAN
LI LIANG

Assignees

华中科技大学

Dates

Publication Date: 20260505
Application Date: 20241230

Claims (8)

1. An apparatus for electro-explosive forming or welding of tubular elements based on an array of metal foils, comprising: The metal foil array is composed of a plurality of metal foils, the plurality of metal foils are uniformly distributed along the circumferential direction and are used for generating phase change and multi-point shock waves at a plurality of preset explosion points at the same time after pulse current is introduced so as to drive the corresponding area of the first pipe fitting to be processed to deform; Electrodes positioned at two ends of the metal foil array are used for being connected with a pulse power supply so as to supply power to each metal foil in parallel; An end plate closely attached to the outer surface of the electrode for preventing axial shake when the first pipe fitting to be processed is deformed; The fixed screw rod axially penetrates through the end plate and is used for coaxially fixing the first pipe fitting to be processed and the electrode; The device comprises an electrode, an insulating positioning block, a limiting metal foil array, a first pipe fitting to be processed, a first metal foil array, a second metal foil array, a first metal foil array and a second metal foil array, wherein the insulating positioning block is closely attached to the inner surface of the electrode and is used for insulating and separating a first pipe fitting to be processed, the component A is a forming die or a second pipe fitting to be processed; the electrodes are annular electrodes and are matched with the insulating positioning blocks to radially press the edges of the two ends of the metal foil array.
2. The apparatus of claim 1, wherein the array of metal foils supports replacement, the number and/or position of the metal foils in the array is adjusted according to the forming requirements to accommodate different dies, the size, shape, thickness and/or material of each metal foil is the same, and the size of the impact load is adjusted according to the forming requirements.
3. The apparatus according to claim 2, wherein the predetermined explosion sites of the respective metal foils are identical or different in height, the predetermined explosion sites being narrowest positions on the cut metal foils, and the height values being adjusted according to the forming requirements to fit different molds.
4. The apparatus of claim 1, wherein the insulating positioning block has a T-shaped cross-section double cylinder structure with a top width matching the diameter of the metal foil and a bottom width matching the inner diameter of the first pipe to be processed when the assembly a is placed inside the first pipe to be processed.
5. The apparatus according to any one of claims 1 to 4, further comprising a vacuum tube extending from the electrode center hole for connecting the work deformation space with a vacuum pump, the vacuum pump for continuously vacuum-treating the whole work deformation space so as to maintain the air pressure in the work deformation direction environment at the time of explosion not to exceed 10kPa.
6. The apparatus of any one of claims 1 to 4, further comprising a support block surrounding an outer surface of the array of metal foils for preventing leakage of shock waves generated by explosion of the metal foils.
7. A method of electro-explosive forming or welding of tubular elements based on an array of metal foils, characterized in that it is applied to a device as claimed in any one of claims 1 to 6, comprising: Placing and fixing the assembly A and the first pipe fitting to be processed, so that the first pipe fitting to be processed is positioned between the assembly A and the metal foil array, the metal foil array is tightly attached to the surface of the first pipe fitting to be processed, the radial distance between each metal foil and the first pipe fitting to be processed is equal, and the assembly A and the first pipe fitting to be processed are fixed in the axial direction; Simultaneously loading pulse high voltage to a plurality of metal foils of the metal foil array through a pulse power supply so as to conduct the metal foils to generate instantaneous pulse high current; each metal foil is subjected to phase change at a preset explosion point position so as to generate electric explosion, and impact load is generated in the electric explosion process; Under the simultaneous action of the multipoint impact load, a plurality of areas of the first pipe fitting to be processed are deformed at high speed and collide with a component A, so that the curved surface component is formed or welded, and the component A is a forming die or a second pipe fitting to be processed.
8. The method of claim 7, wherein the amount of energy deposited prior to explosion of the metal foil is varied by varying the magnitude and/or pulse width of the pulsed current.

Description

Device and method for electro-explosive forming or welding of pipe fittings based on metal foil array Technical Field The application belongs to the field of pipe fitting forming and manufacturing, and more particularly relates to a device and a method for pipe fitting electric explosion forming or welding based on a metal foil array. Background High rate forming is a process technique that uses high density energy, such as blast shock waves, pulsed electromagnetic forces, as the impact load. As a newly proposed high-speed forming technology, the metal foil electric explosion forming technology has the advantages of low cost, high efficiency, high controllability, easiness in realizing automation and the like. The main principle is that the metal foil is loaded with pulse high voltage so as to carry out six phase change stages of solid state heating, liquefying, liquid state heating, gasifying, breakdown ionization and plasma evolution. In the phase change process, generated gasification shock waves and plasma shock waves act on the workpiece, the workpiece to be formed is driven to deform and collide with the die at high speed, the workpiece is attached to the die, and finally the workpiece is processed into a finished product with a required shape. The electric explosion device is relatively simple, has low cost, does not need heating or continuous friction in the forming process, can not form a heat affected zone, can furthest reduce the formation of intermetallic compounds, has higher practical application value, and can be popularized in a large area. Currently, the metal foil electro-explosion forming technology has been primarily applied to the processing and forming of plate-type two-dimensional planar members. However, the method is limited by the basic principle of electric explosion, and the method faces challenges in the treatment of curved surface components, firstly, the electric explosion can be smoothly carried out without separating the formation of a plasma channel and the accumulation of deposition energy, however, the existing electric explosion technology is difficult to effectively form the plasma channel with controllable length and radian on the surface of a curved surface workpiece. And uncontrollable formation of the plasma channel is embodied in uncertainty of explosion point and explosion time. The former causes the action area of explosive force load and the forming precision to be difficult to ensure, the latter causes the deposition energy to be unable to be effectively accumulated, the forming degree is difficult to reach the expectations, in addition, other problems are faced, such as the electric explosion impact force of a single metal foil is relatively concentrated, the deformation area of a processed workpiece is smaller, the processing is required to be processed for a plurality of times in the forming process of large-size pipe fittings, the operation is relatively complex, and in addition, when the processed area of the workpiece is relatively airtight, such as a longer pipe fitting is contracted and deformed inwards, the air between the workpiece and a die or other workpieces is difficult to be discharged at the moment of electric explosion deformation, the deformation compresses the air, the air resistance consumes explosion energy, and the forming effect is weakened. Patent CN113458234a discloses a device and a method for forming a workpiece by using a metal foil to be electrified and explode a shock wave, pulse current is supplied to the metal foil through the pulse power supply system, the metal foil explodes under the action of the pulse current to generate a severe shock wave, oxidation-reduction reaction is carried out between the metal foil and liquid in the liquid environment in the explosion process of the metal foil to release a large amount of energy, and under the action of the shock wave and the energy, the metal workpiece to be processed generates mechanical response to be processed and formed. The method has the following defects that 1) the whole device, particularly a metal foil, must be immersed in water environment by electrohydraulic explosion, the electrohydraulic explosion cannot be applied to workpieces which are not suitable for being immersed in water, and under the action of high current, a plurality of metal workpieces can chemically react with water to generate byproducts which damage the strength of the workpieces, 2) the electrohydraulic explosion adopts uniform metal foil which has no obvious weak points structurally, under the action of pulse current, the metal foil can explode at any position, so that the loading position of explosion impact force is random, the forming precision is greatly influenced, and 3) due to the property of electrohydraulic fluid, the impact wave generated by any electric explosion can be converted into spherical impact wave under the constraint of liquid, so that the technology can only perform spherical fo