Electromagnetic hydraulic forming device and method for metal corrugated pipe

Abstract

The invention relates to the technical field of metal corrugated pipe forming, in particular to a metal corrugated pipe electromagnetic hydraulic forming device and method. The outer guide assembly is rotationally connected above the lower sealing assembly; the fragmentation positioning assembly is arranged on the side wall of the outer guide assembly; the upper sealing assembly is arranged above the fragmentation positioning assembly; the magnetic field generator is arranged above the upper sealing assembly; an extrusion cavity is defined by the upper sealing assembly, the lower sealing assembly and the outer guide assembly, and a pipe blank is arranged in the extrusion cavity; an annular cavity is defined by the exterior of the pipe blank and the outer guide assembly. The forming die sheet is arranged in the annular cavity; the inner guide piston is arranged in the pipe blank, and a forming cavity is formed between the interior of the pipe blank and the exterior of the inner guide piston. The forming die piece can be instantly and completely pressed, the tangential component of the instantaneous stress of the metal material is infinitely close to zero in the ultra-high-speed forming state, springback-free forming of the metal material is achieved, and the forming precision of the metal corrugated pipe is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal bellows forming, and in particular to an electromagnetic hydraulic forming device and a forming method for a metal bellows. Background Art

[0002] For most metal materials, under ultra-high speed forming conditions, some grain boundaries will be activated, while inhibiting the generation and expansion of voids and cracks, so that the plasticity of the material can be improved to a certain extent. This theory has been widely recognized by the academic community. However, in actual production, the material strain rate needs to be increased to The strain rate of traditional high pressure forming method is generally 0.1s -1 The rate of ultra-high-speed forming is more than 2 orders of magnitude higher than that of the traditional internal high-pressure forming method, and it is extremely difficult to achieve this process with existing methods.

[0003] Electromagnetic forming is a new process for plastic forming of metal materials, which can realize ultra-high-speed forming of metals. However, the existing electromagnetic forming process has strict requirements on materials, and non-ferromagnetic materials cannot be applied to this process. The forming process parameters of ferromagnetic materials are obviously different according to the strength of their magnetism, and a large number of experimental verifications are required to determine the process parameters. In addition, electromagnetic forming can only form products with relatively simple shapes at present, and is not suitable for the forming process of metal materials with complex shapes and structures or complex metal flow processes.

[0004] The materials of metal bellows (especially precision metal bellows used in aerospace) are mainly austenitic stainless steel, nickel-based high-temperature alloys, titanium alloys, etc. These materials have obvious springback during the forming process, and the forming springback is relatively large depending on the material and the amount of deformation. For products such as metal bellows with relatively complex shapes and large forming springback, it is difficult for existing forming devices and methods to accurately determine the forming springback through design calculations and experimental verification, which seriously affects the forming accuracy and product quality of precision metal bellows.

[0005] To this end, the present application provides a metal bellows electromagnetic hydraulic forming device and forming method. Summary of the invention

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an electromagnetic hydraulic forming device and a forming method for a metal bellows, which solves the technical problem in the prior art that due to the relatively complex shape of the metal bellows and the large forming springback, it is difficult to accurately determine the forming springback through design calculation and experimental verification, which seriously affects the forming accuracy and product quality of the precision metal bellows.

[0007] In order to achieve the above-mentioned purpose, the first aspect of the present invention provides an electromagnetic hydraulic forming device for a metal bellows, which includes: a lower sealing component; an outer guide component, which is rotatably connected to the upper part of the lower sealing component; a slice positioning component, which is arranged on the side wall of the outer guide component; an upper sealing component, which is arranged above the slice positioning component and is connected to the outer guide component; a magnetic field generator, which is arranged above the upper sealing component and is connected to both the upper sealing component and the outer guide component; wherein the upper sealing component, the lower sealing component and the outer guide component enclose an extrusion cavity, the tube blank is placed inside the extrusion cavity, and the outside of the tube blank is connected to the outer guide component An annular cavity is enclosed between the parts; a forming die is arranged inside the annular cavity and abuts against the slice positioning component and the outer guide component; an inner guide piston is placed inside the tube blank and connected to the upper sealing component, and a forming cavity is formed between the inside of the tube blank and the outside of the inner guide piston; a piston hole is arranged on the lower sealing component and corresponds to the inner guide piston; a liquid injection hole is arranged on the side wall of the upper sealing component and communicated with the forming cavity; the outer guide component can drive the slice positioning component to rotate so that the slice positioning component deviates from the extrusion cavity, and the forming die is separated from the slice positioning component and abuts against the outer guide component and the tube blank.

[0008] Optionally, the lower sealing assembly includes: a lower sealing seat; and a lower sealing outer ring, which is arranged between the tube blank and the outer guide assembly and connected to the lower sealing seat.

[0009] Optionally, the external guide assembly includes: a guide post, rotatably connected to the lower sealing seat; an upper support plate, sleeved over the guide post and connected to the guide post and the magnetic field generator; a guide post knob, disposed above the upper support plate and connected to the guide post, thereby driving the guide post to rotate relative to the lower sealing seat.

[0010] Optionally, there are multiple guide pillars, and the multiple guide pillars are evenly spaced and arranged on the lower sealing seat along the horizontal direction.

[0011] Optionally, the slice positioning assembly includes: spacers, which are arranged at intervals on the side walls of the guide pillars along the vertical direction, and there are multiple spacers. A mold positioning groove is provided between two adjacent spacers, and the molding mold is arranged in the mold positioning groove; fixing bolts are connected between the guide pillars and the spacers.

[0012] Optionally, the volumes of the plurality of spacers gradually increase from top to bottom along the vertical direction.

[0013] Optionally, the upper sealing assembly includes: an upper sealing outer ring, which is arranged above the uppermost spacer and connected to the guide column and the tube blank; and an upper sealing member, which is arranged above the upper sealing outer ring.

[0014] The present invention further provides a method for electromagnetic hydraulic forming of a metal bellows, which is applied to the electromagnetic hydraulic forming device of the metal bellows according to the first aspect. The forming method comprises: S1: Selection and design, according to the determined parameters of the target bellows, the molding pressure P of the target bellows is obtained: ; in, is the tensile strength of the target bellows material, in MPa; is the wall thickness of the tube, in mm; d is the inner diameter of the tube, in mm; Then the drum wave pressure P' is: ; Wherein, a is the drum wave coefficient; P is the molding pressure of the target bellows, unit: MPa; According to the Ampere force calculation formula: F=nILB, where n is the number of coil turns, unit turns; I is the current intensity, unit A; L is the coil length, unit m; B is the magnetic induction intensity required for forming, unit T; In the actual forming process, the required Ampere force F' is: ; Among them, A' is the first-order dimensionless coefficient; Then, through integration, the magnetic induction intensity B' required for the drum wave is: ; The magnetic induction intensity B required for forming is: ; S2: The molding device is installed, the outer guide assembly, the slice positioning assembly and the molding die are positioned and installed, the tube blank is installed in the extrusion cavity, the inner guide piston is installed in the tube blank, and the volume of the molding cavity minus the volume of the inner guide piston is equal to the volume of the filled molding medium, and the volume of the filled molding medium is equal to the volume of the target bellows inner cavity, and then the upper sealing assembly and the lower sealing assembly are installed, and the molding medium is injected into the molding cavity through the injection hole, and then the magnetic field generator is passed with current; S3: Bellows preforming, start the magnetic field generator, the inner guide piston moves downward through the piston hole, adjust the magnetic induction intensity, slowly increase from zero to B', and maintain for 3min~10min. After the tube is preformed, turn off the magnetic field generator, rotate the outer guide assembly, and make the slice positioning assembly away from the extrusion cavity; S4: Bellows forming, start the magnetic field generator, make the magnetic induction intensity reach B instantly, the inner guide piston moves downward at high speed, so that the forming mold pieces are all pressed together to obtain the target bellows, and then turn off the magnetic field generator.

[0015] The beneficial effects of the present invention are: The present invention provides a metal bellows electromagnetic hydraulic forming device and a forming method. Before the tube blank is formed, by setting the outer guiding component to be rotatably connected with the lower sealing component, the outer guiding component drives the segmented positioning component to rotate to the inner side of the outer guiding component, installs the forming die piece on the segmented positioning component, and then installs the tube blank, the inner guiding piston, the upper sealing component and the lower sealing component. Among them, the upper sealing component, the lower sealing component and the outer guiding component enclose an extrusion cavity, the tube blank is placed inside the extrusion cavity, and an annular cavity is enclosed between the outside of the tube blank and the outer guiding component. Then, by rotating the outer guiding component, the segmented positioning component is driven to rotate away from the extrusion cavity, so that the inner wall of the forming die piece abuts against the tube blank, and the outer wall of the forming die piece abuts against the outer guiding component. With such a setting, when an electric current is passed into the magnetic field generator and a forming medium is injected into the forming cavity during the process of forming the tube blank, the forming die pieces are instantaneously all pressed together. Since an inner guiding piston with a suitable volume is installed in advance, the volume of the filled forming medium is equal to the volume of the inner cavity of the target bellows. Therefore, there is no need to discharge the forming medium during the entire forming process, which enables the electromagnetic field generated by the magnetic field generator to drive the inner guiding piston to highly compress the forming medium in the forming cavity, thereby realizing the ultra-high-speed internal high-pressure forming process of the metal bellows. In the ultra-high-speed forming state, the movement of some grain boundaries occurs, and at the same time, the generation of voids, cracks and crack propagation in the metal material is inhibited, so that the plasticity of the metal material is improved, and thus a metal bellows with a larger wave depth ratio can be manufactured. In addition, in the ultra-high-speed forming state, the tangential component of the instantaneous stress of the metal material is infinitely close to zero, thereby realizing the non-elastic recovery forming of the metal material, and significantly improving the forming accuracy and product quality of the precision metal bellows.

[0016] Further, since the forming device of the present invention makes the forming cavity completely sealed by setting the upper sealing component and the lower sealing component, and can replace the inner guiding pistons with different diameters, the volume of the filled forming medium is equal to the volume of the inner cavity of the target bellows before and after forming, that is, the volume in the forming cavity is constant, avoiding the filling and discharging of the forming medium during the forming process, and realizing the ultra-high-speed forming process.

[0017] Further, the present invention uses the electromagnetic field generated by the magnetic field generator to form a high Lorentz force, which further drives the liquid in the forming cavity to generate high pressure to realize the forming of the metal material, avoiding the limitation of the selection of electromagnetic forming materials, and making the forming device and the forming method applicable to non-ferromagnetic metal materials. Description of the Drawings

[0018] Figure 1 It is a cross-sectional schematic view of the metal bellows electromagnetic hydraulic forming device (installation stage of the forming device) of the present invention; Figure 2 It is a cross-sectional schematic view of the metal bellows electromagnetic hydraulic forming device (bellows forming stage) of the present invention.

[0019] Description of the Reference Numerals: 1. Lower sealing assembly; 2. Lower sealing seat; 3. Lower sealing outer ring; 4. Outer guide assembly; 5. Guide post; 6. Upper support plate; 7. Guide post knob; 8. Slice positioning assembly; 9. Spacer; 10. Fixing bolt; 11. Molding mold; 12. Upper sealing assembly; 13. Upper sealing outer ring; 14. Upper sealing member; 15. Magnetic field generator; 16. Inner guide piston; 17. Piston hole; 18. Injection hole. DETAILED DESCRIPTION

[0020] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0021] The embodiment of the present invention provides a metal bellows electromagnetic hydraulic forming device, such as Figure 1 and Figure 2 As shown, the molding device comprises: a lower sealing component 1; an outer guide component 4, which is rotatably connected to the upper part of the lower sealing component 1; a slice positioning component 8, which is arranged on the side wall of the outer guide component 4; an upper sealing component 12, which is arranged above the slice positioning component 8 and connected to the outer guide component 4; a magnetic field generator 15, which is arranged above the upper sealing component 12 and connected to both the upper sealing component 12 and the outer guide component 4; wherein the upper sealing component 12, the lower sealing component 1 and the outer guide component 4 enclose an extrusion cavity, the tube blank is placed inside the extrusion cavity, and an annular cavity is enclosed between the outer part of the tube blank and the outer guide component 4; a molding die 11, which is provided It is placed inside the annular cavity and abuts against the slice positioning component 8 and the outer guide component 4; the inner guide piston 16 is placed inside the tube blank and connected to the upper sealing component 12, and a molding cavity is formed between the inside of the tube blank and the outside of the inner guide piston 16; the piston hole 17 is arranged on the lower sealing component 1 and corresponds to the inner guide piston 16; the injection hole 18 is arranged on the side wall of the upper sealing component 12 and is connected to the molding cavity; the outer guide component 4 can drive the slice positioning component 8 to rotate, so that the slice positioning component 8 moves away from the extrusion cavity, and the molding die 11 is separated from the slice positioning component 8, and abuts against the outer guide component 4 and the tube blank.

[0022] Exemplarily, the molding device in this embodiment is cylindrical as a whole, the tube blank is entirely inside the molding device, and the magnetic field generator 15 is arranged directly above the molding cavity, so that the force generated during the electromagnetic hydraulic molding process acts evenly on the tube blank, thereby improving the molding quality of the metal bellows.

[0023] Exemplarily, a circular hole adapted for the installation of the outer guide assembly 4 is provided on the lower sealing assembly 1, so that the outer guide assembly 4 can rotate relative to the lower sealing assembly 1. Since the slice positioning assembly 8 is connected to the outer guide assembly 4, the outer guide assembly 4 can drive the slice positioning assembly 8 to rotate synchronously, and the slice positioning assembly 8 rotates between the position in the annular cavity and the position away from the extrusion cavity. The slice positioning assembly 8 can specifically achieve a rotation angle of 45° to 360°, such as 60°, 90°, 180°, 270° or 360°. When the slice positioning assembly 8 is away from the extrusion cavity, it can avoid the pressing of the molding die 11 during the molding process and avoid interference with the molding die 11 during the molding process.

[0024] Exemplarily, the molding device in this embodiment is provided with an upper sealing component 12 and a lower sealing component 1. The specific sealing method of the upper sealing component 12 and the lower sealing component 1 is to use a rubber sealing ring to ensure that the molding medium in the molding cavity will not leak.

[0025] Exemplarily, the end of the inner guide piston 16 facing the upper sealing assembly 12 is provided with a thread, and the end face of the upper sealing assembly 12 facing the inner guide piston 16 is provided with a screw hole, so as to facilitate the replacement of the inner guide piston 16 of different diameters, so that the molding device can prepare metal bellows of different sizes, thereby increasing the versatility of the molding device of this embodiment.

[0026] For example, the injection hole 18 in this embodiment is opened on the side wall of the upper sealing component 12, connecting the outside of the molding device with the molding cavity, so as to facilitate the injection of molding medium into the molding cavity. The molding medium in this embodiment is not limited to liquid media such as water or oil. Under the premise of considering the change in compression volume, gas can also be directly used as the molding medium.

[0027] In a possible embodiment, Figure 1 and Figure 2 As shown, the lower sealing assembly 1 includes: a lower sealing seat 2; a lower sealing outer ring 3, which is arranged between the tube blank and the outer guide assembly 4 and connected to the lower sealing seat 2.

[0028] For example, the lower sealing seat 2 in this embodiment is disc-shaped, the lower sealing outer ring 3 is annular, the lower sealing outer ring 3 and the lower sealing seat 2 are connected by bolts, and the lower sealing outer ring 3 and the guide pillar 5 are abutted, which is convenient for assembling the lower sealing outer ring 3. The lower sealing outer ring 3 and the tube blank are sealed, and a sealing rubber ring can be used for sealing to ensure that the molding medium in the molding cavity will not leak during the molding process.

[0029] In a possible embodiment, Figure 1 and Figure 2As shown, the outer guide assembly 4 includes: a guide post 5, which is rotatably connected to the lower sealing seat 2; an upper support plate 6, which is sleeved on the guide post 5 and connected to the guide post 5 and the magnetic field generator 15; a guide post knob 7, which is arranged above the upper support plate 6 and connected to the guide post 5, thereby driving the guide post 5 to rotate relative to the lower sealing seat 2.

[0030] Exemplarily, a circular hole is opened on the lower sealing seat 2 to facilitate the guide pillar 5 to be inserted into the lower sealing seat 2 so that the guide pillar 5 can rotate relative to the lower sealing seat 2 .

[0031] Exemplarily, the guide post knob 7 of this embodiment is fixedly connected to the guide post 5, specifically, it can be welded, connected with bolts and nuts, or integrally formed, and then rotating the guide post knob 7 can drive the guide post 5 to rotate synchronously.

[0032] Exemplarily, the upper support plate 6 is mainly used to connect the guide column 5 and the magnetic field generator 15, so the upper support plate 6 and the magnetic field generator 15 are fixedly connected; and because the guide column 5 needs to rotate, the upper support plate 6 and the guide column 5 are movably connected to facilitate the rotation of the guide column 5. The specific movable connection method is the existing technology and is not limited here.

[0033] In a possible embodiment, Figure 1 and Figure 2 As shown, there are multiple guide pillars 5 , and along the horizontal direction, the multiple guide pillars 5 are evenly spaced and arranged on the lower sealing seat 2 .

[0034] For example, the number of guide pillars 5 can be set to 2, and the two guide pillars 5 are symmetrically arranged on both sides of the inner guide piston 16. The side wall of each guide pillar 5 is provided with 5 spacers 9, and a mold positioning groove is provided between each two adjacent spacers 9, that is, 4 mold positioning grooves are provided. The spacers 9 on the side walls of the two guide pillars 5 are also symmetrically arranged, and the heights of the two opposite spacers 9 are the same. Figure 1 As shown, the top spacer 9 of the left guide post 5 and the top spacer 9 of the right guide post 5 are at the same height, so that the heights of the relatively arranged die positioning grooves are the same, and the forming die 11 is placed horizontally. Then, when the tube blank is placed vertically, the corrugations on the corrugated tube obtained after forming are just perpendicular to the axial direction of the corrugated tube, ensuring the forming quality of the metal corrugated tube after forming. According to actual needs, the heights of the four die positioning grooves can be the same or different, and can be determined according to the corrugation requirements of the target metal corrugated tube.

[0035] For example, the number of guide pillars 5 can be set to 3, and the 3 guide pillars 5 are evenly spaced and arranged in the circumference of the inner guide piston 16, and the side wall of each guide pillar 5 is provided with 5 spacers 9, and a mold positioning groove is provided between each two adjacent spacers 9, that is, 4 mold positioning grooves are provided, and the spacers 9 on the side walls of the 3 guide pillars 5 are also symmetrically arranged, and the heights of the 3 relative spacers 9 are the same. The technical effect brought about by such an arrangement is the same as that described above, and will not be repeated here.

[0036] In a possible embodiment, Figure 1 and Figure 2 As shown, the slice positioning assembly 8 includes: spacer blocks 9, which are arranged at intervals on the side walls of the guide column 5 along the vertical direction, and the number of spacer blocks 9 is multiple. A mold positioning groove is provided between two adjacent spacer blocks 9, and the molding mold 11 is arranged in the mold positioning groove; a fixing bolt 10 is connected between the guide column 5 and the spacer block 9.

[0037] For example, Figure 2 As shown, the spacer 9 is fixedly connected to the guide post 5 by a fixing bolt 10, and the spacer 9 also rotates as the guide post 5 rotates. In the installation stage of the molding device, the spacer 9 is located on the inner side of the guide post 5, that is, it is arranged toward the molding cavity, so that the die positioning groove between two adjacent spacers 9 is used to place the molding die 11. The molding die 11 is annular, and the inner ring of the molding die 11 abuts against the tube blank, and the outer ring of the molding die 11 abuts against the guide post 5. In this way, in the corrugated tube molding stage, the guide post 5 drives the spacer 9 to rotate, and the molding die 11 is suspended by the abutment force between the tube blank and the guide post 5. In this way, when the magnetic field generator 15 is turned on, the molding die 11 abuts against the guide post 5 and the tube blank, so the friction between the molding die 11 and the guide post 5 and the tube blank is very small, and the friction is almost zero compared with the downward pressure of the magnetic field generator 15, so the molding die 11 can be pressed together instantly, and then the target corrugated tube is obtained.

[0038] For example, Figure 1 and Figure 2 As shown, five spacers 9 are provided on each side guide column 5. Specifically, the number of the spacers 9 can be determined according to the actual needs of the metal bellows and is not specifically limited here.

[0039] For example, the position of the fixing bolt 10 on the guide column 5 can be moved up and down according to actual needs, so as to adjust the fixing position of the spacer block 9 on the guide column 5, so that the distance between two adjacent spacers 9 can be adjusted to meet the needs of fixing the molding molds 11 of different heights. Specifically, a plurality of bolt holes on the guide column 5 can be provided in the vertical direction to meet the needs of adjusting a plurality of fixing bolts 10 up and down.

[0040] In a possible embodiment, Figure 1 and Figure 2As shown, along the vertical direction, from top to bottom, the volumes of the plurality of spacers 9 gradually increase.

[0041] For example, because the molding die 11 is first set in the die positioning groove during the installation stage of the molding device, the weight of the molding die 11 is supported by the spacer 9. In the vertical direction, as the number of molding die 11 increases, the lower the spacer 9 is, the more weight it needs to support for the weight of the multiple molding die 11 above it. Therefore, by setting the volume of the lowest spacer 9 to the maximum, the load-bearing capacity of the spacer 9 at the bottom can be improved, avoiding the weight of the molding die 11 being supported only by the spacer 9 and the fixing bolt 10, resulting in damage to the connection between the fixing bolt 10 and the spacer 9.

[0042] In a possible embodiment, Figure 1 and Figure 2 As shown, the upper sealing assembly 12 includes: an upper sealing outer ring 13, which is arranged above the uppermost spacer block 9 and connected to the guide column 5 and the tube blank; and an upper sealing member 14, which is arranged above the upper sealing outer ring 13.

[0043] For example, the upper sealing outer ring 13 and the upper sealing member 14 are connected by bolts, and the upper sealing outer ring 13 and the guide pillar 5 are in abutment, so that the friction between the upper sealing outer ring 13 and the guide pillar 5 is minimized during the molding process. The upper sealing outer ring 13 and the tube blank are sealed, and a sealing rubber ring can be used for sealing to ensure that the molding medium in the molding cavity will not leak during the molding process.

[0044] This embodiment also provides a method for electromagnetic hydraulic forming of a metal bellows, which is applied to the electromagnetic hydraulic forming device of the metal bellows in the above embodiment. The forming method includes: S1: Selection and design, the target bellows material is 316L stainless steel, specifically 022Cr 17 Ni 12 Mo 2 According to the determined parameters of the target bellows, the inner diameter of the target bellows is 31mm, the outer diameter is 42.7mm, the wave height is 5mm, the wave distance is 4.5mm, the wave thickness is 3.3mm, the number of waves is 17, and the straight side length is 4mm, then the molding pressure P of the target bellows is obtained: ; in, The tensile strength of the target bellows material is 650Mpa; is the wall thickness of the tube, which is 0.5mm; d is the inner diameter of the tube, which is 31mm; P is calculated to be 20.97Mpa; Then the drum wave pressure P' is: ; Wherein, a is the drum wave coefficient, which is generally 0.7-0.8, and in this embodiment, a=0.75; P is the molding pressure of the target bellows, P=20.97Mpa; then P'=15.73Mpa is calculated; According to the Ampere force calculation formula: F=nILB, where n is the number of coil turns, which is 5 turns; I is the current intensity, which is 10A; L is the coil length, which is 0.5m; In the actual forming process, the required Ampere force F' is: ; Wherein, A' is a first-order dimensionless coefficient, generally 1.2 to 1.5, and in this embodiment, A'=1.5; Then, through integration, the magnetic induction intensity B' required for the drum wave is: ; The magnetic induction intensity required for the drum wave is calculated to be B'=15.73÷25=0.63T; The magnetic induction intensity B required for forming is: ; The magnetic induction intensity required for molding is calculated to be B=1.5×0.63=0.95T; S2: The molding device is installed, and the outer guide assembly 4, the slice positioning assembly 8 and the molding die 11 are positioned and installed. In this embodiment, the parameters of the molding die 11 are the die inner diameter of 32.6 mm, the die thickness of 4.0 mm, the interval between the upper and lower adjacent molding die 11 is 13.25 mm, the inner guide piston 16 is selected to have a diameter of 20.5 mm, the tube blank and the inner guide piston 16 are installed in the molding cavity, and in this embodiment, the diameter of the inner guide piston 16 is 20.5 mm. The height of the spacer 9 is adjusted so that the interval between the two upper and lower adjacent spacers 9 is 13.25-4=9.25 mm. The volume of the molding cavity minus the volume of the inner guide piston 16 is equal to the volume filled with the molding medium, and the volume filled with the molding medium V 0 Equal to the volume V of the target bellows cavity 1 , then install the upper sealing assembly 12 and the lower sealing assembly 1, inject the molding medium into the molding cavity through the injection hole 18. The molding medium in this embodiment is deionized water, and then the magnetic field generator 15 is passed with a current I=10A; S3: Bellows preforming, start the magnetic field generator 15, the inner guide piston 16 moves downward through the piston hole 17, adjust the magnetic induction intensity, slowly increase from zero to B'=0.63T, and keep it for 5 minutes. After the tube is preformed, turn off the magnetic field generator 15, rotate the outer guide assembly 4, and make the slice positioning assembly 8 away from the extrusion cavity; S4: Bellows forming, start the magnetic field generator 15, make the magnetic induction intensity instantly reach B=0.95T, the inner guide piston 16 moves downward at high speed, so that the forming mold pieces 11 are all pressed together to obtain the target bellows, and then turn off the magnetic field generator 15.

[0045] After step S4, the magnetic field generator 15 is adjusted to flip the magnetic field direction by 180°, and the magnetic field generator 15 is restarted to slowly move the inner guide piston 16 upward to the initial position. The upper sealing assembly 12 and the lower sealing assembly 1 are then disassembled in sequence, the formed target metal bellows product is taken out, and finally the forming die 11 is removed, and the cleaning and drying are performed in sequence to prepare the forming device for use.

[0046] Exemplarily, the above-mentioned forming method is applicable to a variety of commonly used materials such as austenitic stainless steel, martensitic stainless steel, titanium alloy or high-temperature alloy for preparing precision metal bellows products.

[0047] According to the forming method provided in this embodiment, since the forming method is a method step for a metal bellows electromagnetic hydraulic forming device provided in the first aspect of the present invention, the forming method has all the technical effects of a metal bellows electromagnetic hydraulic forming device, and will not be repeated here.

[0048] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0050] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A metal bellows electromagnetic hydraulic forming device, characterized in that: include: Lower sealing assembly; An outer guide assembly, rotatably connected above the lower sealing assembly; A slice positioning assembly, arranged on the side wall of the outer guide assembly; An upper sealing assembly is disposed above the slice positioning assembly and connected to the outer guide assembly; A magnetic field generator is disposed above the upper sealing assembly and connected to the upper sealing assembly and the outer guide assembly; The upper sealing component, the lower sealing component and the outer guide component enclose an extrusion cavity, the tube blank is placed inside the extrusion cavity, and an annular cavity is enclosed between the outside of the tube blank and the outer guide component; A molding die is disposed inside the annular cavity and abuts against the slice positioning assembly and the outer guide assembly; An inner guide piston is disposed inside the tube blank and connected to the upper sealing assembly, and a forming cavity is formed between the inside of the tube blank and the outside of the inner guide piston; a piston hole, provided on the lower sealing assembly and corresponding to the inner guide piston; A liquid injection hole, arranged on the side wall of the upper sealing component and connected to the molding cavity; The outer guide assembly can drive the slice positioning assembly to rotate, so that the slice positioning assembly moves away from the extrusion cavity, and then the molding die is separated from the slice positioning assembly and abuts against the outer guide assembly and the tube blank.

2. The electromagnetic hydraulic forming device for metal bellows according to claim 1, characterized in that: The lower sealing assembly comprises: Lower sealing seat; The lower sealing outer ring is arranged between the tube blank and the outer guide assembly and is connected to the lower sealing seat.

3. The electromagnetic hydraulic forming device for metal bellows according to claim 2, characterized in that: The outer guide assembly comprises: A guide column, rotatably connected to the lower sealing seat; An upper support plate, sleeved on the guide pillar, and connected to the guide pillar and the magnetic field generator; The guide post knob is arranged above the upper support plate and connected with the guide post, thereby driving the guide post to rotate relative to the lower sealing seat.

4. The electromagnetic hydraulic forming device for metal bellows according to claim 3, characterized in that: There are a plurality of guide pillars, and along the horizontal direction, the plurality of guide pillars are evenly spaced and arranged on the lower sealing seat.

5. The electromagnetic hydraulic forming device for metal bellows according to claim 3, characterized in that: The slice positioning component includes: Spacers are arranged at intervals on the side walls of the guide pillars along the vertical direction. There are multiple spacers, and a mold positioning groove is provided between two adjacent spacers. The molding mold is arranged in the mold positioning groove. A fixing bolt is connected between the guide column and the spacer block.

6. The electromagnetic hydraulic forming device for metal bellows according to claim 5, characterized in that: Along the vertical direction, from top to bottom, the volumes of the plurality of spacers gradually increase.

7. The electromagnetic hydraulic forming device for metal bellows according to claim 6, characterized in that: The upper sealing assembly comprises: An upper sealing outer ring is arranged above the uppermost spacer and is connected to the guide pillar and the tube blank; The upper sealing member is arranged above the upper sealing outer ring.

8. A method for electromagnetic hydraulic forming of a metal bellows, applied to the electromagnetic hydraulic forming device of a metal bellows as claimed in any one of claims 1 to 7, characterized in that: The molding method comprises: S1: Selection and design, according to the determined parameters of the target bellows, the molding pressure P of the target bellows is obtained: ； in, is the tensile strength of the target bellows material, in MPa; is the wall thickness of the tube, in mm; d is the inner diameter of the tube, in mm; Then the drum wave pressure P' is: ； Wherein, a is the drum wave coefficient; P is the molding pressure of the target bellows, unit: MPa; According to the Ampere force calculation formula: F=nILB, where n is the number of coil turns, unit turns; I is the current intensity, unit A; L is the coil length, unit m; B is the magnetic induction intensity required for forming, unit T; In the actual forming process, the required Ampere force F' is: ； Among them, A' is the first-order dimensionless coefficient; Then, through integration, the magnetic induction intensity B' required for the drum wave is: ； The magnetic induction intensity B required for forming is: ； S2: The molding device is installed, the outer guide assembly, the slice positioning assembly and the molding die are positioned and installed, a tube blank is installed in the extrusion cavity, the inner guide piston is installed in the tube blank, and the volume of the molding cavity minus the volume of the inner guide piston is equal to the volume of the filled molding medium, and the volume of the filled molding medium is equal to the volume of the target bellows inner cavity, and then the upper sealing assembly and the lower sealing assembly are installed, and the molding medium is injected into the molding cavity through the injection hole, and then the magnetic field generator is passed with current; S3: Bellows preforming, start the magnetic field generator, the inner guide piston moves downward through the piston hole, adjust the magnetic induction intensity, slowly increase from zero to B', and maintain for 3min~10min. After the tube blank is preformed, turn off the magnetic field generator, rotate the outer guide assembly, and make the slice positioning assembly away from the extrusion cavity; S4: Bellows forming, start the magnetic field generator, make the magnetic induction intensity reach B instantly, the inner guide piston moves downward at high speed, make the forming mold pieces all pressed together, get the target bellows, and then turn off the magnetic field generator.

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