A magnetic pulse bulging connection device and method for titanium alloy-stainless steel pipes

Abstract

The present invention relates to a magnetic pulse bulging connection device and method for titanium alloy-stainless steel pipes, including a coaxial positioning block with a metal pipe to be formed arranged inside. The metal pipe to be formed is composed of a titanium alloy pipe and a stainless steel pipe. The stainless steel pipe is sleeved on the outer side of one end of the titanium alloy pipe, and there is a gap between the titanium alloy pipe and the stainless steel pipe. A forming coil is arranged inside the working area of the titanium alloy pipe, and a magnetic collector is arranged between the forming coil and the inner surface of the titanium alloy pipe. The forming coil is connected to a capacitor power supply system. The present invention has a reasonable design. By using the magnetic pulse bulging method to carry out high-speed impact welding on the titanium alloy pipe and the stainless steel pipe, it has high bonding strength, good controllability, high efficiency, and does not require complex processes and harsh working conditions, solving the problems in the welding effect and production flexibility of welding titanium alloy and stainless steel pipes using the prior art.

Description

Technical Field:

[0002] The present invention belongs to the technical field of magnetic pulse connection, and particularly relates to a magnetic pulse bulging connection device and method for titanium alloy-stainless steel pipes. Background Art:

[0004] Titanium alloy has good properties such as low density, high specific strength, and strong corrosion resistance. Its density is 40% smaller than that of steel, and its strength is equivalent to that of steel pipes. However, the material price of titanium and its alloys is expensive. Stainless steel is a commonly used structural material with excellent properties and relatively low cost. Combining titanium alloy with stainless steel pipes can give full play to the advantages of both, which helps to broaden the application of titanium alloy / stainless steel connecting pipes in the fields of aerospace, rail transit, and medical devices.

[0005] However, there are significant differences in the linear expansion coefficient, thermal conductivity, and elastic modulus between titanium alloy and stainless steel. Direct fusion welding is prone to serious segregation, stress gradient and other defects at the joint, and titanium and iron elements are easy to combine to form brittle intermetallic compounds, resulting in brittle fracture of the joint. In addition, in order to meet the actual service performance, pipe connection usually requires very high shape and size accuracy and stable and consistent microstructure. Therefore, it is very difficult to obtain good pipe welding joints.

[0006] At present, the welding methods for titanium alloy and stainless steel pipes mainly include electron beam welding, laser welding, explosion welding, brazing, diffusion welding, and friction welding, etc. Electron beam welding needs to be carried out in a vacuum environment, and it is difficult to avoid the generation of brittle intermetallic compounds at the joint; laser welding has expensive equipment, high requirements for the welding site, and is not flexible enough for production use; explosion welding, brazing, diffusion welding, and friction welding have very high requirements for the control of welding process, and are not suitable for complex welding structures and large-scale production.

[0007] Therefore, it is necessary to develop a new welding method for titanium alloy and stainless steel pipes. Summary of the Invention:

[0009] Aiming at the problems existing in the above-mentioned prior art, the present invention provides a magnetic pulse bulging connection device and method for titanium alloy-stainless steel pipes, which is reasonably designed, effectively improves the bonding strength of titanium alloy-stainless steel pipes, and has stable and reliable quality.

[0010] To achieve the above object, the technical solution adopted by the present invention is: a magnetic pulse bulging connection device for titanium alloy-stainless steel pipes, including a coaxial positioning block with a to-be-formed metal pipe arranged inside. The to-be-formed metal pipe is composed of a titanium alloy pipe and a stainless steel pipe. The stainless steel pipe is sleeved outside one end of the titanium alloy pipe, and there is a gap between the titanium alloy pipe and the stainless steel pipe. A forming coil is arranged inside the working area of the titanium alloy pipe. A magnetic collector is arranged between the forming coil and the inner surface of the titanium alloy pipe. The forming coil is connected to a capacitor power supply system.

[0011] Further, a pipe positioning hole with an axis extending horizontally is arranged inside the coaxial positioning block. The pipe positioning hole is a stepped hole. The titanium alloy pipe is accommodated in the small-diameter section of the pipe positioning hole, and the stainless steel pipe is accommodated in the large-diameter section of the pipe positioning hole.

[0012] Further, the forming coil includes a coil skeleton. A spiral tube coil with a rectangular cross-section is wound on the coil skeleton. The outside of the spiral tube coil is coated with fiberglass cloth and fixed with epoxy resin glue.

[0013] Further, a limit block and a lateral fixing block are respectively arranged at both axial ends of the coil skeleton. The limit block is located at the lower end inside the titanium alloy pipe and on one side of the coil outlet of the forming coil. Both side surfaces of the limit block are in contact with the coaxial positioning block and the coil skeleton respectively. The lateral fixing block is located inside the stainless steel pipe, and the lateral fixing block is in contact with the surface of the magnetic collector.

[0014] Further, both the limit block and the lateral fixing block are made of insulating materials. The limit block is semi-cylindrical, and the lateral fixing block is stepped shaft-shaped. One end of the lateral fixing block away from the magnetic collector penetrates through the coaxial positioning block and extends outwards.

[0015] Further, the coaxial positioning block includes an upper positioning block and a lower positioning block that are butt-jointed up and down. Arc-shaped grooves for matching with the outer diameter of the to-be-formed pipe are arranged inside both the upper positioning block and the lower positioning block. The arc-shaped groove of the upper positioning block and the arc-shaped groove of the lower positioning block are spliced up and down to form the pipe positioning hole.

[0016] Further, threaded countersunk holes extending vertically are distributed on the die closing surface of the lower positioning block. Connecting studs passing through the upper positioning block are screwed in the threaded countersunk holes. A locking nut is screwed on the upper end of the connecting stud. A side plate pressing on the stepped surface of the lateral fixing block is arranged at the side end of the lower positioning block. The side plate is connected to the lower positioning block by bolts. Arc-shaped handles are respectively fixed at both ends of the upper positioning block.

[0017] Further, the capacitor power supply system includes a pulsed capacitor, a high-voltage generator, a high-voltage switch, a rectifier, and a current-limiting resistor. The forming coil is connected to the pulsed capacitor through a wire. The pulsed capacitor is connected to the high-voltage generator through a wire. A high-voltage switch is connected in series on the wire connecting the pulsed capacitor and the forming coil. A rectifier and a current-limiting resistor are connected in series on the wire connecting the high-voltage generator and the pulsed capacitor.

[0018] Further, a driving ring is bonded to the inner surface of the working area of the titanium alloy tube. The driving ring is made of a metal material with low resistivity and low yield strength.

[0019] Another technical solution adopted by the present invention is: a magnetic pulse bulging connection method for titanium alloy-stainless steel pipes, comprising the following steps:

[0020] Step S1: Grind the surfaces of the titanium alloy tube and the stainless steel tube to be connected to remove the oxide layer and impurities.

[0021] Step S2: Coaxially place the forming coil, the magnetic collector, the titanium alloy tube, and the stainless steel tube in the lower positioning block from inside to outside in sequence. There is a gap between the titanium alloy tube and the stainless steel tube.

[0022] Step S3: Docking and locking the upper positioning block and the lower positioning block up and down, and fixing the side plate at the side end of the lower positioning block to fix the coil, the magnetic collector, the titanium alloy tube, and the stainless steel tube.

[0023] Step S4: Use the capacitor power supply system to charge and discharge the forming coil, so that the titanium alloy tube expands outward, undergoes bulging plastic deformation, and collides with the stainless steel tube at high speed to achieve high-strength metallurgical bonding.

[0024] Further, in step S2, the materials of the forming coil and the magnetic collector are copper and copper alloy respectively.

[0025] Further, in step S2, the gap between the titanium alloy tube and the stainless steel tube is set to 1.5 - 3 mm.

[0026] Further, in step S3, the materials of the coaxial positioning block include bakelite, epoxy resin, and 45 steel.

[0027] Further, in step S4, the discharge voltage is 1 - 20 kV.

[0028] Further, in step S4, the inner surface of the titanium alloy tube is spaced 1 mm from the surface of the magnetic collector. The inner surface of the titanium alloy tube is wrapped with insulating tape to prevent gap discharge.

[0029] Compared with the prior art, the present invention has the following effects: The present invention is reasonably designed. By subjecting the titanium alloy tube to magnetic pulse bulging and performing high-speed impact welding with the stainless steel tube, it has the advantages of high bonding strength, good controllability, high efficiency, and does not require complex processes and stringent working conditions, solving the problems in welding effect and production flexibility when welding titanium alloy and stainless steel tubes using the prior art. BRIEF DESCRIPTION OF THE DRAWINGS:

[0031] Figure 1 is a schematic main sectional structure diagram of an embodiment of the present invention;

[0032] Figure 2 is a schematic three-dimensional structure diagram of an embodiment of the present invention;

[0033] Figure 3 is a schematic position structure diagram of the titanium alloy tube and the stainless steel tube in an embodiment of the present invention.

[0034] In the figure:

[0035] 1 - stainless steel tube; 2 - titanium alloy tube; 3 - helical tube coil; 4 - coil skeleton; 5 - magnetic collector; 6 - limit block; 7 - lateral fixing block; 8 - lower positioning block; 9 - side plate; 10 - bolt; 11 - upper positioning block; 12 - locking nut; 13 - connecting stud; 14 - forming coil; 15 - pulse capacitor; 16 - high-voltage generator; 17 - high-voltage switch; 18 - rectifier; 19 - current-limiting resistor; 20 - pipe positioning hole; 21 - capacitor power supply system; 22 - arc handle; 23 - driving ring. DETAILED DESCRIPTION OF THE EMBODIMENTS:

[0037] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0038] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, 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 should not be construed as a limitation of the present invention.

[0039] The welding of titanium alloys and stainless steel falls under the category of dissimilar material welding. The chemical and physical properties of Ti and Fe differ significantly, and the two elements easily combine to form brittle intermetallic compounds, weakening the joint performance. Existing technologies place high demands on welding site conditions or welding process control. To address the problems of existing connection technologies that easily generate intermetallic compounds at the weld interface of titanium alloys and stainless steel pipes and provide low production flexibility, this application proposes the use of magnetic pulse welding technology to achieve a high-strength metallurgical bond between titanium alloys and stainless steel pipes.

[0040] Example 1: Figures 1 - 2 As shown, the present invention discloses a magnetic pulse bulging connection device for titanium alloy and stainless steel pipes, comprising a coaxial positioning block with a metal pipe to be formed disposed therein. The metal pipe to be formed comprises a titanium alloy pipe 2 and a stainless steel pipe 1. The stainless steel pipe 2 is sleeved outside one end of the titanium alloy pipe 1, with a gap between the two pipes. The portion of the titanium alloy pipe 2 extending into the interior of the stainless steel pipe 1 forms a working area. A forming coil 14 is disposed within the working area of the titanium alloy pipe 2, with a magnetic flux collector 5 disposed between the forming coil 14 and the inner surface of the titanium alloy pipe 2. The forming coil 14 is connected to a capacitor power supply system 21. During operation, the forming coil is charged and discharged using the capacitor power supply system, and the titanium alloy pipe and the stainless steel pipe are subjected to high-speed impact welding through magnetic pulse bulging. This achieves a high-strength metallurgical bond between the titanium alloy pipe and the stainless steel pipe, resulting in high bond strength, good controllability, and high efficiency. This eliminates the need for complex processes and harsh working conditions, thereby resolving the welding problems and production flexibility associated with conventional welding techniques for titanium alloy and stainless steel pipes.

[0041] In this embodiment, the outer diameter of the titanium alloy tube 2 is smaller than the inner diameter of the stainless steel tube 1. When performing magnetic pulse connection, the connection end of the titanium alloy tube is located in the middle of the connection end of the stainless steel tube.

[0042] In this embodiment, the interior of the coaxial positioning block is provided with a tube positioning hole 20 whose axis extends transversely, and the tube positioning hole 20 is a stepped hole; the titanium alloy tube 2 is accommodated in the small diameter section of the tube positioning hole 20, and the stainless steel tube 1 is accommodated in the large diameter section of the tube positioning hole 20.

[0043] In this embodiment, the formed coil 14 includes a coil frame 4, on which a helical coil 3 with a rectangular cross section is wound. The outer side of the helical coil 3 is covered with glass cloth and fixed with epoxy resin glue. Preferably, the helical coil is made of copper.

[0044] In this embodiment, the magnetic flux collector 5 is a rotating body with side seams, and its cross section is trapezoidal, with an inner surface length greater than an outer surface length, and an inner diameter slightly greater than an outer diameter of the formed coil.

[0045] In this embodiment, a limiting block 6 and a lateral fixing block 7 are respectively arranged at two axial ends of the coil bobbin 4. The limiting block 6 is located at the lower end inside the titanium alloy tube 2 and is arranged on one side of the coil outlet of the formed coil 14. Two side surfaces of the limiting block 6 are respectively in contact with the coaxial positioning block and the coil bobbin 4. The lateral fixing block 7 is located inside the stainless steel tube 1, and the lateral fixing block 7 is in contact with the surface of the magnetic collector 5, so as to fix the position of the magnetic collector 5.

[0046] In this embodiment, the magnetic collector 5, the formed coil 14 and the tube to be formed are coaxial at the center.

[0047] In this embodiment, both the limiting block 6 and the lateral fixing block 7 are made of insulating materials, such as insulating materials like bakelite or resin materials.

[0048] In this embodiment, the limiting block 6 is in the shape of a semi-cylinder, and the lateral fixing block 7 is in the shape of a stepped shaft. One end of the lateral fixing block 7 away from the magnetic collector 5 penetrates through the coaxial positioning block and extends outwards.

[0049] In this embodiment, the coaxial positioning block includes an upper positioning block 11 and a lower positioning block 8 which are butted up and down. Arc-shaped grooves for matching with the outer diameter of the tube to be formed are arranged inside both the upper positioning block 11 and the lower positioning block 8. The arc-shaped groove of the upper positioning block 11 and the arc-shaped groove of the lower positioning block 8 are spliced up and down to form a tube positioning hole.

[0050] In this embodiment, threaded countersunk holes extending vertically are distributed on the mold clamping surface of the lower positioning block 8. A connecting stud 13 penetrating through the upper positioning block 11 is screwed in the threaded countersunk holes. A locking nut 12 is screwed at the upper end of the connecting stud 13. The upper and lower positioning blocks are connected and fixed by the locking nut and the connecting stud. A side plate 9 pressing on the stepped surface of the lateral fixing block 7 is arranged at the side end of the lower positioning block 8. The side plate 9 is connected with the lower positioning block 8 through a bolt 10 to fix the lateral fixing block.

[0051] In this embodiment, in order to facilitate the movement of the upper positioning block, arc-shaped handholds 22 are respectively fixed at two ends of the upper positioning block 11.

[0052] In this embodiment, the capacitor power supply system 21 includes a pulse capacitor 15, a high-voltage generator 16, a high-voltage switch 17, a rectifier 18, and a current-limiting resistor 19. The forming coil 14 is connected to the pulse capacitor 15 through a wire. The pulse capacitor 15 is connected to the high-voltage generator 16 through a wire. A high-voltage switch 17 is connected in series on the wire connecting the pulse capacitor 15 and the forming coil 14. A rectifier 18 and a current-limiting resistor 19 are connected in series on the wire connecting the high-voltage generator 16 and the pulse capacitor 15. During operation, the pulse capacitor bank is charged by the charging system, and electrical energy is stored in the pulse capacitor bank. When the high-voltage switch is closed, the stored electrical energy is instantaneously released to the forming coil to generate a pulse current, generating a strong pulse magnetic field around the forming coil. Due to the electromagnetic induction law, an induced eddy current is excited in the titanium alloy tube. The current direction in the forming coil is opposite to the direction of the induced eddy current in the tube material, so the magnetic fields generated by the two interact to generate a strong electromagnetic force. Through the adjustment of the magnetic collector, the magnetic field in the area to be connected of the tube material is strengthened, and the distribution of the electromagnetic force is changed. When the generated electromagnetic repulsive force reaches the yield strength of the metal tube to be formed, the titanium alloy tube is driven to rapidly undergo plastic deformation outward and achieve high-speed impact welding with the stainless steel tube.

[0053] Such as Figure 1 、 Figure 2As shown in the figure, a magnetic pulse bulging connection method for titanium alloy-stainless steel pipes includes the following steps: (1) Place the forming coil 14 with a magnetic collector 5 in the lower positioning block 8 and connect it to the capacitor power supply system 21. (2) Clean the working surface of the pipe to be formed: Grind the joint surfaces of both the stainless steel pipe 1 and the titanium alloy pipe 2, wipe them with alcohol, then place the stainless steel pipe 1 and the titanium alloy pipe 2 into the inner cavity of the coaxial positioning block. Through the cooperation of the coil skeleton 1 and the titanium alloy pipe 2, make the magnetic collector 5, the forming coil 14 and the center of the pipe to be formed coaxial. Subsequently, connect the side plate 9 and the lower positioning block 8 with bolts 10. (3) Place the limit block 6 on one side of the outlet of the forming coil 14, make the magnetic collector 5 correspond to the working area of the titanium alloy pipe 2, place the lateral fixing block 7 inside the stainless steel pipe 1 and make it contact the surface of the magnetic collector 5. Screw the connecting stud 13 into the lower positioning block 8 and then place it into the upper positioning block 11, and tighten the locking nut 12. (4) Charge the pulse capacitor group 15 through the charging system, store the electric energy in the pulse capacitor group 15, close the high-voltage switch 17, and the stored electric energy is instantly released to the forming coil 14 to generate a pulse current, generating a strong pulse magnetic field around the forming coil 14. Due to the electromagnetic induction law, an induced eddy current is excited in the titanium alloy pipe 2. The current direction in the forming coil 14 is opposite to the direction of the induced eddy current in the pipe, so the magnetic fields generated by the two interact to generate a strong electromagnetic force. Through the adjustment of the magnetic collector, the magnetic field in the area to be connected of the pipe is strengthened, and the distribution of the electromagnetic force is changed. When the generated electromagnetic repulsion force reaches the yield strength of the metal pipe to be formed, it drives the titanium alloy pipe 2 to expand rapidly outward, undergoes bulging plastic deformation, and realizes high-speed impact welding with the stainless steel pipe 1, achieving high-strength metallurgical bonding. (5) After the discharge is completed, first unscrew the locking nut 12 of the upper positioning block 11 and disassemble the upper positioning block 11, then unscrew the bolt 10 on the side plate 9 to separate the side plate 9 and the lower positioning block 8, take out the lateral fixing block 7, and finally take out the connected pipe axially. Subsequently, repeat steps 1-5 for the next group of titanium alloy and stainless steel pipes for the bulging process.

[0054] In this embodiment, an insulating layer is provided on the inner surface of the titanium alloy pipe 2, and the magnetic collector and the titanium alloy pipe are as close as possible while ensuring insulation.

[0055] In this embodiment, in order to enhance the connection strength of the connected pipes, the titanium alloy pipe 2 can be annealed before connection, and the annealing temperature of the titanium alloy is set to 500-750 °C.

[0056] In this embodiment, the gap between the titanium alloy pipe and the stainless steel pipe is set to 1.5-3 mm.

[0057] In this embodiment, the forming coil 14 and the magnetic collector 5 are made of copper and copper alloy respectively.

[0058] In this embodiment, the materials of the coaxial positioning block and the side plate include bakelite, epoxy resin, and 45 steel.

[0059] Embodiment 2: As Figure 3 shown, the difference between this embodiment and Embodiment 1 is that: according to the material characteristics of titanium alloy and stainless steel, combined with the principle of magnetic pulse bulging, considering that the resistivity of titanium is relatively large, a driving ring 23 is bonded to the inner surface of the working area of the titanium alloy tube 2. The driving ring 23 is made of a metal material with low resistivity and low yield strength. This driving ring has high electrical conductivity and can obtain a higher induced current on the surface of the metal tube according to the principle of electromagnetic induction, resulting in a greater electromagnetic force. Therefore, the bonding strength of the interface can be greatly improved under the same energy.

[0060] In this embodiment, the driving ring and the titanium alloy tube are connected by a metal adhesive, and the metal adhesive is acrylate glue or epoxy glue.

[0061] In this embodiment, the driving ring is a metal material with low resistivity and low yield strength, such as 1 series aluminum alloy or annealed copper with resistivity of 2.65 Ω•cm and 1.67 Ω•cm respectively. The thickness of the driving ring is 1 - 3 mm, which is determined by the skin depth and the discharge frequency.

[0062] The advantages of the present invention are as follows:

[0063] (1) The present invention uses magnetic pulse bulging to perform high-speed impact welding on titanium alloy tubes and stainless steel tubes, achieving high-strength bonding between titanium alloy tubes and stainless steel tubes;

[0064] (2) The present invention is carried out at room temperature without changing the temperature of the pipe material. The original structure on the surface of the pipe fitting can be maintained in the microstructure, ensuring the comprehensive mechanical properties of the pipe surface; the stable and uniform radial volume force avoids local defects and ensures the uniformity of pipe connection; the heat affected zone of the weld in magnetic pulse connection is very small, reducing the generation of intermetallic compounds; there are no strict on-site requirements during the connection process, and the surface of the connected pipe can be ensured to be smooth through bulging connection;

[0065] (3) The present invention can control the welding process and accurately control the welding effect by reasonably adjusting the discharge voltage and the gap between the titanium alloy tube and the stainless steel tube, and controlling the impact speed of the titanium alloy tube. In addition, by regulating the magnetic field through a magnetic concentrator, the connection area can be controlled, and thus flexible production can be carried out according to actual needs;

[0066] (4) The present invention has a simple structure, is easy to operate, has good controllability, good production flexibility, high efficiency, is easy to realize production mechanization, and there is no radiation, no waste gas, and no condensate water during the whole connection process.

[0067] If the present invention discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (such as connection using bolts or screws), or it can also be understood as: a non-detachable fixed connection (such as riveting, welding). Of course, the mutual fixed connection can also be replaced by an integral structure (such as manufactured integrally by casting process) (except where it is clearly impossible to use the integral forming process).

[0068] In addition, in any of the technical solutions disclosed in the present invention above, the terms used to represent the positional relationship or shape, unless otherwise stated, include states or shapes that are approximate, similar or close to them.

[0069] Any component provided by the present invention can either be assembled from a plurality of individual components or be a single component manufactured by an integral forming process.

[0070] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that: it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A magnetic pulse bulging connection device for titanium alloy - stainless steel pipes, characterized in that: It includes a coaxial positioning block with a metal pipe to be formed internally arranged therein. The metal pipe to be formed is composed of a titanium alloy pipe and a stainless steel pipe. The stainless steel pipe is sleeved on the outer side of one end of the titanium alloy pipe, and there is a gap between the titanium alloy pipe and the stainless steel pipe. A forming coil is arranged inside the working area of the titanium alloy pipe, and a magnetic collector is arranged between the forming coil and the inner surface of the titanium alloy pipe. The forming coil is connected to a capacitor power supply system; The inside of the coaxial positioning block is provided with a pipe positioning hole whose axis extends horizontally. The pipe positioning hole is a stepped hole; the titanium alloy pipe is accommodated in the small-diameter section of the pipe positioning hole, and the stainless steel pipe is accommodated in the large-diameter section of the pipe positioning hole; The forming coil includes a coil skeleton, and a rectangular-section spiral tube coil is wound on the coil skeleton. The outer side of the spiral tube coil is coated with a glass cloth and fixed with an epoxy resin adhesive; Axial ends of the coil skeleton are respectively provided with a limiting block and a lateral fixing block. The limiting block is located at the lower end inside the titanium alloy pipe and is arranged on one side of the coil outlet of the forming coil. Two side surfaces of the limiting block are respectively in contact with the coaxial positioning block and the coil skeleton; the lateral fixing block is located inside the stainless steel pipe, and the lateral fixing block is in contact with the surface of the magnetic collector; The coaxial positioning block includes an upper positioning block and a lower positioning block which are butted up and down. The inside of both the upper positioning block and the lower positioning block is provided with an arc-shaped groove for matching with the outer diameter of the pipe to be formed. The arc-shaped groove of the upper positioning block and the arc-shaped groove of the lower positioning block are spliced up and down to form the pipe positioning hole; The capacitor power supply system includes a pulsed capacitor, a high-voltage generator, a high-voltage switch, a rectifier and a current-limiting resistor. The forming coil is connected to the pulsed capacitor through a wire. The pulsed capacitor is connected to the high-voltage generator through a wire. A high-voltage switch is connected in series on the wire connecting the pulsed capacitor and the forming coil. A rectifier and a current-limiting resistor are connected in series on the wire connecting the high-voltage generator and the pulsed capacitor.

2. The magnetic pulse expansion forming connection device for a titanium alloy-stainless steel pipe according to claim 1, wherein: Both the limiting block and the lateral fixing block are made of insulating materials. The limiting block is in the shape of a semi-cylinder, and the lateral fixing block is in the shape of a stepped shaft. One end of the lateral fixing block away from the magnetic collector penetrates through the coaxial positioning block and extends outwards.

3. A magnetic pulse bulging connection device for a titanium alloy-stainless steel pipe according to claim 1, characterized in that: Threaded countersunk holes extending vertically are distributed on the die clamping surface of the lower positioning block. Connecting studs penetrating through the upper positioning block are screwed in the threaded countersunk holes. A locking nut is screwed on the upper end of the connecting stud; a side plate pressing on the stepped surface of the lateral fixing block is arranged at the side end of the lower positioning block. The side plate is connected to the lower positioning block through bolts; arc-shaped handles are respectively fixed at both ends of the upper positioning block.

4. A magnetic pulse bulging connection device for a titanium alloy - stainless steel pipe according to claim 1, characterized in that: A driving ring is bonded on the inner surface of the working area of the titanium alloy pipe. The driving ring is made of a metal material with low resistivity and low yield strength.

5. A magnetic pulse bulging connection method for titanium alloy-stainless steel tubes, characterized in that: It includes a magnetic pulse expansion connection device for a titanium alloy-stainless steel pipe using the titanium alloy-stainless steel pipe as described in any one of claims 1 to 4, and the following steps are included: Step S1: Grind the surfaces of the titanium alloy pipe and the stainless steel pipe to be connected to remove the oxide layer and impurities; Step S2: Coaxially place the formed coil, magnetic concentrator, titanium alloy tube, and stainless steel tube inside the lower positioning block in sequence from the inside to the outside, with a gap existing between the titanium alloy tube and the stainless steel tube; Step S3: Vertically butt and lock the upper positioning block and the lower positioning block, and fix the side plate to the side end of the lower positioning block to fix the coil, magnetic concentrator, titanium alloy tube, and stainless steel tube; Step S4: Use the capacitor power supply system to charge and discharge the formed coil, causing the titanium alloy tube to expand outward, undergo bulging plastic deformation, and collide with the stainless steel tube at high speed to achieve high-strength metallurgical bonding.

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