Metal tee pipe bulging device and method based on laser shock wave

Abstract

The application discloses a metal tee pipe bulging processing device and method based on laser shock waves and belongs to the field of plastic processing forming of pipes. The device comprises a light guide system, a heating system, a control system and a workpiece die system. The device contains symmetrical front and rear half dies, and a vertical main pipe cavity is arranged in the middle after the closure. A metal pipe and a wedge-shaped concave seat are installed in the main pipe cavity, and the bottom of the metal pipe is inserted into the wedge-shaped concave seat. A branch pipe cavity is arranged laterally in the main pipe cavity. A pressing component is installed on the top of the split die. An inclined concave surface is arranged on the top of the wedge-shaped concave seat, the inclined direction of the inclined concave surface is arranged towards the branch pipe cavity, the focal point of the inclined concave surface is coincident with the bottom end of the center line of the branch pipe cavity, and the inclined concave surface is coated with an absorption layer. The device solves the problem that the high-pressure plasma generated by ionization of the absorption layer cannot be directionally converged in the prior art, and avoids the technical problem that the pipe lacks forming stability at the bulging guide.

Description

Technical Field

[0001] The device of this invention belongs to the field of plastic forming of pipe fittings, specifically relating to a device and method for forming metal tee pipes based on laser shock waves. Background Technology

[0002] A tee, also known as a pipe tee or tee fitting, is a pipe connector with three openings: one inlet and two outlets, or two inlets and one outlet. Tees are primarily used to change the direction of fluid flow, where a branch line needs to be opened from the main pipeline. For example, in automotive piping systems, the tee is a "flow distribution hub" used in cooling, braking, and air conditioning systems. Currently, 30°~45° angled tees are widely used, allowing for flow-direction connections and replacing the potentially energy-consuming and safety-hazardous 90° right-angle tees. Depending on the application requirements, tees are made of materials such as carbon steel, cast steel, alloy steel, stainless steel, copper, aluminum alloy, and plastic.

[0003] Existing metal tee forming methods mainly include welding forming, filler extrusion forming, hydraulic bulging forming, and hot pressing forming.

[0004] Welding requires simple equipment and uses a centralized heat source to locally heat the components. Traditional flame welding not only has disadvantages such as high operational difficulty, poor forming accuracy, and uneven inner wall surface of the formed tee pipe affecting fluid flow performance, but also easily causes problems such as burning through the pipe wall, deformation of components, insufficient wetting of solder, and incomplete welding. The cost of rework for pipeline leakage is extremely high in the later stage.

[0005] The filler extrusion molding method involves extruding straight metal pipe fittings filled with internal filler. A punch pushes the metal pipe fitting from both ends, forcing the metal fitting and filler through radial holes in the die to form the final shape. This process requires a filler medium, such as rubber, nylon, or polyurethane rubber, during the bulging process. When using elastic materials as the force transmission medium, the root of the branch pipe is prone to excessive thinning or even cracking, and the top of the branch pipe may collapse. The height of the formed branch pipe is limited, making it difficult to meet the production requirements of high-profile tees. The process also suffers from poor stability and low material forming limits.

[0006] Hydraulic bulging can form multiple pipe fittings with different cross-sectional shapes in one step, reducing the number of molds and eliminating the need for subsequent welding processes. This results in high-quality pipe fittings and high production efficiency. However, hydraulic forming is extremely sensitive to process parameters, equipment precision, and material properties. The forming process parameter window is narrow and difficult to control, requiring a dedicated hydraulic press and control system capable of providing ultra-high pressure. Sealing elements are consumable parts and require frequent replacement. Precise design of the mold parting surface and sealing structure is also necessary. These factors create a complex system, and improper control can easily lead to various forming defects.

[0007] Explosive bulging is a promising new method for tee tubes that can replace flexible medium bulging. It involves placing explosives inside the metal tube and using the shock wave generated by the explosion as the force source for bulging. Explosive bulging of metal tee tubes has advantages such as simple molds, high processing pressure, and high production efficiency. However, in actual processing, the amount of explosive is difficult to control precisely, and the process itself is inherently dangerous.

[0008] Laser shock wave bulging processing utilizes the laser emitted by a laser to act on the absorption layer. The absorption layer absorbs energy and vaporizes to form plasma. The plasma continues to absorb energy and explodes to generate a shock wave that acts on the inner surface of the metal tube that needs to be bulged. Because the surface is deformed by the force effect of the shock wave, it is suitable for various bulging requirements.

[0009] However, traditional laser shock wave bulging devices are prone to problems such as excessive local thinning, shape deviation, and cracking when dealing with complex shapes, large bulging ratios, or low-plasticity materials, thus limiting the forming limit. Furthermore, traditional laser shock wave bulging devices often use a sloping plane as the absorption layer attachment surface. After absorbing laser energy, the absorption layer vaporizes and ionizes, forming high-pressure plasma that diffuses in all directions, failing to converge and form a combined force. Therefore, it is necessary to greatly increase the energy of the laser shock wave to compensate for energy loss. Therefore, this invention proposes a metal tee tube bulging processing device and method based on laser shock waves. Summary of the Invention

[0010] To overcome the above deficiencies, this invention provides a metal tee tube bulging processing device and method based on laser shock waves, which solves the technical problem that the existing technology is unable to achieve directional convergence of high-pressure plasma generated by ionization of the absorption layer, resulting in a lack of forming stability at the bulging guide.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] A metal tee tube bulging processing device based on laser shock waves includes:

[0013] The workpiece mold system includes a split mold, which is assembled from a completely symmetrical front mold and a rear mold. After the front mold and the rear mold are closed, a vertical main cavity is set in the middle. A metal pipe and a wedge-shaped concave seat are installed in the main cavity. The bottom of the metal pipe is inserted into the wedge-shaped concave seat. A branch cavity is provided in the lateral connection of the main cavity. The branch cavity is used for the metal pipe to be heated and deformed into a tee pipe blank. A clamping component is installed on the top of the split mold for pressing down from the end of the metal pipe.

[0014] A constraint layer is filled inside the metal pipe fitting. The constraint layer is a transparent material with a high boiling point. An inclined concave surface is provided on the top of the wedge-shaped concave seat. The upper arc chord of the inclined concave surface along the vertical section forms an inclination angle of 30º with the axial section. The inclination direction of the inclined concave surface is directed towards the branch lumen, and the focal point of the inclined concave surface coincides with the bottom end of the center line of the branch lumen. An absorbent layer is coated on the inclined concave surface of the wedge-shaped concave seat.

[0015] The light guiding system includes a laser generator and a transmission device. The laser output from the laser generator is transmitted into the main tube cavity through the transmission device, and the direction of transmission is along the axial direction of the main tube cavity.

[0016] The heating system includes a ceramic ring with a resistance wire inside; a half-set of annular grooves is provided in the front half mold and the rear half mold outside the branch pipe cavity, and the ceramic ring is installed in the assembled annular groove; a heating hole is provided on the side of the annular groove facing the main pipe cavity, and the heating hole contacts the surface of the metal pipe.

[0017] The control system is used to control the opening and closing of the laser generator and its output parameters, as well as the operating parameters of the resistance wire.

[0018] In a further technical solution, baffles are installed on the same side of the front half mold and the rear half mold, and multiple sets of bolts are installed to connect the front half mold and the rear half mold; the baffles are used to laterally seal the annular groove.

[0019] The bottoms of the front half mold, the rear half mold, and the wedge-shaped concave seat are all constrained on the worktable;

[0020] In a further technical solution, the control system includes a computer and a controller, wherein control information is input by the computer and transmitted to the controller to control the laser parameters emitted by the laser generator and the working status of the resistance wire;

[0021] In a further technical solution, the transmission device includes a light guide tube connected to the output end of the laser generator. The laser generator emits a laser pulse beam that is directed toward a total reflection mirror mounted on the frame, forming a reflection and being injected into the main tube cavity through an impact head installed at the bottom.

[0022] One end of the light guide tube is connected to the laser generator, and the other end of the light guide tube is connected to the impact head; the total reflection mirror is installed in the light guide tube, and the output direction of the impact head is inclined to the upper concave surface of the wedge-shaped concave seat along the axis of the metal tube, so that the laser pulse beam is emitted from the laser generator and irradiates the inclined concave surface of the wedge-shaped concave seat in sequence through the light guide tube, the total reflection mirror, and the impact head;

[0023] In a further technical solution, the clamping component includes a pressure plate, and an annular block is provided on the side of the pressure plate facing the main tube cavity; the annular block and the pressure plate are coaxial and have a through hole in the middle for the laser pulse beam to pass through; the outer diameter of the annular block is adapted to the inner diameter of the main tube cavity; the bottom of the annular block abuts against the top of the metal pipe fitting.

[0024] Both the top of the front and rear molds are equipped with double-ended studs. One end of the double-ended stud is threaded to the corresponding front or rear mold, and the other end passes through the pressure plate to install the lower washer, spring and upper washer in sequence, and is locked with a nut.

[0025] The nut is threaded onto the double-ended stud and abuts against the upper washer downwards. The upper washer is subjected to force to compress the spring and the lower washer, and compresses the pressure plate to move up and down along the axis of the main tube cavity.

[0026] In a further technical solution, when the laser pulse beam passes through the confinement layer and irradiates the absorption layer, the absorption layer absorbs the energy of the laser and vaporizes and ionizes to form high-pressure plasma; the high-pressure plasma squeezes the metal pipe and causes the metal pipe to deform along the branch cavity.

[0027] In a further technical solution, the ceramic ring body also includes an inner ring ceramic seat, an outer ring ceramic seat, and an annular support block. The inner ring ceramic seat and the outer ring ceramic seat are both semi-circular rings. An arc-shaped groove is provided on the inner ring ceramic seat facing the outer ring ceramic seat, and a resistance wire is installed in the arc-shaped groove.

[0028] The inner and outer ring ceramic seats are stacked and fitted together, and the baffle is used to install the annular support block, the inner ring ceramic seat, and the outer ring ceramic seat into the annular groove by bolts.

[0029] The inner ring ceramic seat is provided with multiple sets of circumferentially arranged heat conduction holes facing the heating hole. The heating hole is provided in multiple sets and is arranged circumferentially. The angle between adjacent heating holes is 10° and the diameter is Φ1.5~Φ5 mm. The heat conduction holes are connected to the heating holes.

[0030] In a further technical solution, two sets of guide holes are provided inside the annular block, and a set of air blowing pipes and a set of air suction pipes are installed respectively, with both the air blowing pipes and the air suction pipes located at the top of the constraint layer.

[0031] A protective shell is fixedly installed at the bottom of the pressure plate. The inner diameter of the protective shell is adapted to the outer diameter of the air blowing pipe or the air suction pipe. An air blowing circuit is set on the outside of the air blowing pipe, and an air suction circuit is set on the outside of the air suction pipe.

[0032] In a further technical solution, the blowing pipe and the suction pipe are connected together on the working plate, which is installed above the constraint layer; a light-transmitting hole is opened in the middle of the working plate, and a beam shaping mirror is installed in the output direction of the impact head to change the spot size of the laser pulse beam and adjust its beam uniformity.

[0033] A bulging method for metal tee tubes based on laser shock wave technology, the specific steps of which are as follows:

[0034] Step 1: First, install the metal pipe to be processed into the cavity of the split mold. During installation, place the front half and rear half of the mold on the worktable. Vertically install a wedge-shaped concave seat in the main pipe cavity of the front half or rear half of the mold. The upper end of the wedge-shaped concave seat extends into the interior of the metal pipe, and the stepped surface of the wedge-shaped concave seat abuts against the lower end face of the metal pipe. An absorbent layer is coated on the inclined concave surface of the wedge-shaped concave seat. The lower end face of the annular block abuts against the upper end face of the metal pipe. The pressure plate is installed on the annular block, and the nut is tightened to compress the spring. Close the front half and rear half of the mold, and install a ceramic ring in the annular groove so that the heat conduction hole faces the heating hole. Then install the annular support block, and then close the annular groove. Use bolts to fix the baffles on the sides of the front half and rear half of the mold. Then inject a high-boiling-point transparent substance into the metal pipe as a constraint layer.

[0035] Step 2: The resistance wire heats the metal pipe fitting, forming a localized area around the branch pipe, raising the temperature of the area of ​​the metal pipe fitting to be formed to a set temperature; the laser generator emits a controlled laser pulse beam, which enters the interior of the metal pipe fitting along its axis and irradiates the absorption layer on the inclined concave surface of the wedge-shaped concave seat. After absorbing the laser energy, the absorption layer vaporizes and ionizes, forming high-pressure plasma; the high-pressure plasma rapidly expands outward, forming a high-amplitude shock wave that propagates outward. This high-amplitude shock wave converges towards the focal point of the concave surface, applying radial shock wave pressure to the inner wall of the area where the branch pipe of the metal pipe fitting is located, causing the pipe wall of the metal pipe fitting to bulge outward along the branch pipe cavity;

[0036] Step 3, synchronized with Step 2: while the high-pressure plasma applies radial pressure to the inner wall of the metal tube, the spring is compressed and applies a downward pressure to the pressure plate, and the metal tube is subjected to axial extrusion force from the annular block.

[0037] Step 4: Under the combined action of the shock wave generated by the high-pressure plasma and the extrusion force of the annular block, the axial length of the metal pipe is reduced, and the pipe wall of the metal pipe bulges outward along the branch cavity of the split mold. The laser generator continuously emits laser pulse beams to impact the metal pipe until the bulging branch reaches the specified length.

[0038] Step 5: Turn off the laser generator and disconnect the resistance wire circuit; remove the spring nut, and take off the pressure plate, spring, and ring block; drain the constraint layer liquid, then open the split mold and take out the tee pipe blank after the metal pipe fitting has been formed;

[0039] Step 6: Use wire cutting to cut off the closed end of the branch pipe of the tee pipe blank after the metal pipe fitting is formed, and obtain the required metal tee pipe.

[0040] In the above forming method, the laser pulse beam parameters are selected based on the material mechanical properties, diameter, wall thickness, and bulging amount of the metal tube to be formed. The laser pulse beam parameters are controlled by a control system, allowing for excellent control of the pressure value of the induced high-pressure plasma. Compared to explosive forming, safety is significantly improved. The controlled laser pulse beam enters the interior of the metal tube along its axis and irradiates the absorption layer on the inclined concave surface of the wedge-shaped concave seat. The metal tube is not located within the irradiated area of ​​the laser pulse beam. The absorption layer absorbing the laser pulse beam energy is not coated on the surface of the metal tube, but rather on the inclined concave surface of the wedge-shaped concave seat, which is separate from the metal tube. A controlled laser pulse beam irradiates the absorption layer, causing the material to vaporize and ionize, forming high-pressure plasma. The high-pressure plasma rapidly expands, generating a high-amplitude shock wave that converges towards the focal point of the concave surface. Under the influence of the inclined concave surface of the wedge-shaped concave seat and the mold cavity, the impact force of the shock wave pointing towards the branch pipe of the mold cavity is greater. The shock wave pushes the metal pipe to undergo plastic deformation according to the mold cavity, and the branch pipe is expanded at the branch pipe of the mold cavity until the extended branch pipe reaches the required length. Depending on the wall thickness of the metal pipe, the length of the extended branch pipe, the mechanical properties of the material, etc., one-time forming or multiple forming can be adopted.

[0041] The present invention has the following beneficial effects:

[0042] 1) This invention uses nanosecond laser-induced high-pressure shock waves for forming processing, which has strong adaptability to the inner diameter of the formed pipe, and the forming is completed in a very short time. The forming process also has the characteristics of high flexibility, no pollution, high production efficiency and good economic benefits.

[0043] 2) This invention uses laser shock wave to expand the tee tube. Compared with traditional welding processing, the surface quality of the tube wall formed by laser expansion is better, the quality is more reliable, and the precision is higher. The tee tube has less resistance to the fluid when used, and the material properties after forming are better and the corrosion resistance is enhanced.

[0044] 3) The requirements for the molds used in this invention are low. The laser shock wave bulging method has lower requirements for the sealing of the mold, while the hydraulic bulging method has higher requirements for the sealing of the mold system and requires frequent maintenance to ensure the sealing.

[0045] 4) Compared to quasi-static forming methods such as filler extrusion molding and hydraulic bulging, the strain rate of laser shock wave induced materials is as high as 10. 7 s -1 The ultra-high strain rate greatly improves the formability of materials such as titanium alloys, magnesium alloys, and stainless steel that are prone to fracture under quasi-static conditions, and significantly increases the forming limit of the materials.

[0046] 5) This invention uses a concave reflective cone with a 30º tilt angle, and the generated high-pressure plasma converges towards the concave focal point; the pulsed laser parameters are controlled by a controller, and the adjustment range can be from a few joules to several hundred joules, and the pulse energy is precisely controllable. Therefore, the peak pressure of the laser-induced shock wave is precisely controllable, and the maximum pressure of the shock wave can reach tens of GPa. Thus, it can not only form metal material pipes with low yield strength, but also form pipes with high yield strength, making up for the shortcomings of using internal high pressure to form high-strength material pipes.

[0047] 6) The present invention uses a heating wire to heat the branch pipe area of ​​the metal pipe to be formed, which further improves the deformation resistance of the material with poor plasticity at room temperature, reduces the deformation resistance, improves plasticity, avoids springback, torsion or delayed cracking after forming, improves the dimensional stability of the pipe, and reduces the residual stress after forming. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the working process of the bulging processing device proposed in this invention;

[0049] Figure 2 This is a schematic diagram of the interior of the split mold proposed in this invention. Figure 1 (not bulging);

[0050] Figure 3 This is a schematic diagram of the interior of the split mold proposed in this invention. Figure 2 (Already swollen);

[0051] Figure 4 This is a three-dimensional schematic diagram of the separation of the ceramic ring body proposed in this invention;

[0052] Figure 5 This is a schematic diagram of the rear half-mold structure proposed in this invention;

[0053] Figure 6 This is a front view of the wedge-shaped concave seat of the present invention;

[0054] Figure 7 This is a cross-sectional view of the wedge-shaped concave seat of the present invention;

[0055] Figure 8 This is a top view of the bulging processing apparatus proposed in this invention;

[0056] Figure 9 This is a vertical sectional view of the split mold proposed in this invention;

[0057] Figure 10 for Figure 9 BB sectional view (excluding parts such as the upper double-ended stud and pressure plate);

[0058] Figure 11 This is a cross-sectional schematic diagram of a split mold according to another embodiment of the present invention;

[0059] Figure 12 for Figure 11 Enlarged view of part M;

[0060] Figure 13 This is a cross-sectional view of a split mold and an internal schematic diagram of part of the light guiding system, representing another embodiment of the present invention.

[0061] Figure 14 for Figure 13 N enlarged images.

[0062] legend:

[0063] 1: Computer; 2: Controller; 3: Laser generator; 4: Light guide tube; 5: Laser pulse beam; 6: Total reflection mirror; 7: Impact head; 8: Front half mold; 9: Rear half mold; 10: Metal fittings; 11: Ring block; 12: Pressure plate; 13: Double-ended stud; 14: Spring; 1501: Upper washer; 1502: Lower washer; 16: Nut; 17: Wedge-shaped concave seat; 171: Inclined concave surface; 18: Absorption layer; 19: Approximately 20: High-pressure plasma; 21: Worktable; 22: Resistance wire; 23: Inner ring ceramic seat; 24: Outer ring ceramic seat; 25: Annular support block; 26: Baffle; 27: Bolt; 28: Heating hole; 29: Split mold; 30: Main tube cavity; 31: Branch tube cavity; 32: Annular groove; 33: Heat conduction hole; 34: Air blowing pipe; 35: Air suction pipe; 36: Protective shell; 37: Working plate; 38: Beam shaping mirror. Detailed Implementation

[0064] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0065] Example 1

[0066] like Figure 1-10The diagram illustrates one embodiment of the present invention, specifically a metal tee tube bulging processing device based on laser shockwave. This device includes a control system, a laser shockwave beam guiding system, a workpiece mold system, and a heating system. The control system comprises a computer 1 and a controller 2. Control information is input from the computer 1 and transmitted to the controller 2 to control the laser parameters emitted by the laser generator 3 and the working status of the resistance wire 22. The energy, spot diameter, pulse width, and wavelength of the laser pulse beam 5 are determined based on the diameter, thickness, and yield strength of the metal tube 10 to be processed. Based on the physical properties of the metal tube 10 material and the geometry of the split mold 29, the temperature rise rate, maximum temperature, and heating duration of the resistance wire 22 are set to ensure that the metal tube 10 material achieves good plasticity without reducing its mechanical properties, thereby ensuring the best bulging processing effect for the metal tube 10.

[0067] like Figure 1 As shown, the light guiding system includes a laser generator and a transmission device. The laser output from the laser generator is transmitted into the main tube cavity through the transmission device, with the transmission direction along the axial direction of the main tube cavity. The transmission device includes a light guide tube 4, a laser pulse beam 5, a total reflection mirror 6, and an impact head 7. One end of the light guide tube 4 is connected to the laser generator 3, and the other end is connected to the impact head 7. The total reflection mirror 6 is installed in the light guide tube 4, and a convex lens is installed in the impact head 7 to focus the laser pulse beam 5. The center line of the impact head 7 is coaxial with the axis of the metal tube 10. The impact head 7 is inclined towards the upper concave surface 171 of the wedge-shaped concave seat 17, so that the laser pulse beam 5 is emitted from the laser generator 3 and sequentially passes through the light guide tube 4, the total reflection mirror 6, and the impact head 7 to irradiate the inclined concave surface 171 of the wedge-shaped concave seat 17. Figure 2 As shown, the upper arc chord of the inclined concave surface 171 of the wedge-shaped concave seat 17 forms a 30º angle with the axial section. This inclined concave surface not only confines the generated high-pressure plasma 20 to a narrow space, greatly improving the impact effect of the shock wave, but also focuses the generated high-pressure plasma 20 at the focal point of the concave surface. The resulting resultant force points towards the cavity area of ​​the branch tube forming of the split mold 29. Silicone heat-resistant black paint is used as an absorption layer 18 coated on the inclined concave surface 171 of the wedge-shaped concave seat 17 to improve the absorption efficiency of the laser pulse beam 5. Compared with traditional black paint, silicone heat-resistant black paint does not dissolve in high-temperature organic solvents, which is beneficial for the propagation of the laser pulse beam in the colorless confinement layer, reducing the energy loss of the laser pulse beam. It has a high absorption rate for laser light, and after being irradiated by laser, it vaporizes and ionizes to produce high-pressure plasma with high pressure.

[0068] The workpiece mold system includes a split mold 29, which is assembled from a completely symmetrical front mold half 8 and a rear mold half 9, such as... Figure 9As shown, after the front half mold 8 and the rear half mold 9 are closed, a vertical main pipe cavity 30 is provided in the middle. A metal pipe fitting 10 and a wedge-shaped concave seat 17 are installed in the main pipe cavity 30. The bottom of the metal pipe fitting 10 is inserted into the wedge-shaped concave seat 17. A branch pipe cavity 31 is provided in the lateral connection of the main pipe cavity 30. The branch pipe cavity 31 is used for the metal pipe fitting 10 to be heated and deformed into a tee pipe blank. A clamping component is installed on the top of the split mold 29 for pressing down from the end of the metal pipe fitting 10.

[0069] A constraint layer 19 is filled inside the metal pipe fitting 10. The constraint layer 19 is a transparent material with a high boiling point. An inclined concave surface 171 is provided on the top of the wedge-shaped concave seat 17. The upper arc chord of the inclined concave surface 171 along the vertical section forms an inclination angle of 30º with the axial section. The inclination direction of the inclined concave surface 171 is set towards the branch cavity 31, and the focal point of the inclined concave surface 171 coincides with the bottom end of the center line of the branch cavity 31. An absorbent layer 18 is coated on the inclined concave surface 171 of the wedge-shaped concave seat 17.

[0070] Both the front mold 8 and the rear mold 9 contain a main pipe cavity and a branch pipe cavity that form the metal pipe fitting 10. The front and rear molds are closed, and a ceramic ring is installed within the annular groove. The ceramic ring includes an inner ring ceramic seat 23, an outer ring ceramic seat 24, and a heating hole 28. The clamping component includes a double-ended stud 13. The lower end of the double-ended stud 13 is threaded onto the split mold 29. The upper end of the double-ended stud 13 passes sequentially through a lower washer 1502, a spring 14, an upper washer 1501, and a pressure plate 12. The upper end of the double-ended stud 13 is threadedly connected to a nut 16. The nut 16 applies pressure to the pressure plate 12 through the compression of the spring 14. The magnitude of the applied pressure is set according to the geometric characteristics of the metal pipe fitting 10 and its material mechanical properties.

[0071] like Figure 8 As shown, the double-ended stud 13, lower washer 1502, spring 14, upper washer 1501, pressure plate 12, and nut 16 are symmetrically distributed on both sides of the central axis of the metal pipe fitting 10, so that the annular block 11 applies uniform pressure to the upper end of the metal pipe fitting 10.

[0072] like Figure 3 As shown, the two ends of the vertical cross-section of the wedge-shaped concave seat 17 are inclined at a 30º angle to the axial cross-section, so that the focal point of the upper inclined concave surface of the wedge-shaped concave seat 17 coincides with the bottom end of the branch center line of the branch pipe formed on the split mold 29. The inclined concave surface of the wedge-shaped concave seat 17 is coated with an absorption layer 18 and inserted into the metal pipe fitting 10. The metal pipe fitting 10 is fitted with a small clearance between the wedge-shaped concave seat 17 and the cavity of the split mold 29. The lowest point of the inclined concave surface of the wedge-shaped concave seat 17 is lower than the lowest point of the branch cavity 31, and the highest point of the inclined concave surface is higher than the highest point of the branch cavity 31. This causes the generated high-pressure plasma 20 to expand rapidly outward and form a high-amplitude shock wave that can act on the cavity area of ​​the branch pipe formed by the split mold 29.

[0073] The absorption layer 18 is used to increase the absorption of laser energy. The metal tube 10 is filled with a transparent high-boiling-point liquid substance as a confinement layer 19, such as high-phenyl silicone oil, to delay the time for the generated high-pressure plasma 20 to diffuse into the air, prolong the action time of the laser shock wave, and improve its effect.

[0074] like Figure 2 , 3 4. The heating system includes a resistance wire 22, an inner ring ceramic seat 23, an outer ring ceramic seat 24, an annular support block 25, a baffle 26, bolts 27, and heating holes 28. Both the inner and outer ring ceramic seats 23 and 24 are composed of two perfectly symmetrical semicircular rings. The baffle 26, via bolts 27, mounts the annular support block 25, the inner ring ceramic seat 23, and the outer ring ceramic seat 24 into the annular groove 32 around the branch pipe of the split mold 29. The resistance wire 22 is also composed of two independent units. The resistance wire 22 is mounted on the inner ring ceramic seat 23 and has a plug for connecting to an external power source. The inner and outer ring ceramic seats 23 and 24 are insulators, stacked together and enclosing the resistance wire 22 in the middle, ensuring that the split mold 29 is not energized. This guarantees the safety of the heating process and facilitates the removal of the processed metal pipe 10 from the split mold 29.

[0075] like Figure 3 As shown, heating holes 28 are distributed around the branch pipe positions of the split mold 29; as Figure 4 and 5 As shown, multiple sets of heat-conducting holes 33 and heating holes 28 are provided; these multiple sets of heating holes are arranged circumferentially and distributed around the branch pipe cavity, such as... Figure 10 As shown. The angle between adjacent heating holes is 10°, and the diameter of heating hole 28 ranges from Φ1.5 to Φ5 mm. For metal fittings 10 with a diameter less than Φ50 mm, the diameter of heating hole 28 is Φ1.5 mm; for metal fittings with a diameter greater than Φ200 mm, the diameter of heating hole 28 is Φ5 mm; for metal fittings 10 with a diameter between Φ50 mm and 200 mm, the diameter of heating hole 28 is determined proportionally. The heat-conducting hole 33 connects to heating hole 28 and extends to the outer wall of metal fitting 10. The function of heating hole 28 is to directly radiate the heat generated by resistance wire 22 onto the outer wall of metal fitting 10, thereby improving the heating efficiency of resistance wire 22. The resistance wire 22 heats metal fitting 10, and the increase in temperature of metal fitting 10 can not only reduce the yield strength of the material of metal fitting 10, but also improve the fracture toughness of the material.

[0076] The specific processing steps are as follows:

[0077] Step 1: First, assemble the split mold 29 forming system, and then install the metal pipe 10 to be processed into the cavity of the split mold 29. During installation, the upper end of the wedge-shaped concave seat 17 extends into the interior of the metal pipe 10, the stepped surface of the wedge-shaped concave seat 17 contacts the lower end surface of the metal pipe 10, the inclined concave surface of the wedge-shaped concave seat 17 is coated with an absorbent layer 18, the lower end surface of the annular block 11 abuts against the upper end surface of the metal pipe 10, the pressure plate 12 is installed on the annular block 11, tighten the nut 16 to compress the spring 14, and then inject a high-boiling-point transparent substance into the interior of the metal pipe 10 as a constraint layer 19.

[0078] Step 2: The resistance wire 22 is energized to form a high-temperature heat source. The heating holes 28 distributed around the branch pipe of the metal pipe 10 heat the local area of ​​the metal pipe 10, raising the temperature of the branch pipe area to be formed to the set temperature. The laser generator 3 emits a controlled laser pulse beam 5. The laser pulse beam 5 enters the interior of the metal pipe 10 along the axis and irradiates the absorption layer 18 on the inclined concave surface of the wedge-shaped concave seat 17. After absorbing the laser energy, the absorption layer 18 vaporizes and ionizes to form a high-pressure plasma 20. The high-pressure plasma 20 rapidly expands outward to form a high-amplitude shock wave that propagates outward. The high-amplitude shock wave converges towards the focal point of the concave surface and applies radial shock wave pressure to the inner wall of the area where the branch pipe of the metal pipe 10 is located, causing the pipe wall of the metal pipe 10 to bulge outward along the branch pipe cavity of the split mold 29.

[0079] Step 3: While the high-pressure plasma 20 applies radial pressure to the inner wall of the metal tube 10, the spring 14 is compressed and applies a downward pressure to the pressure plate 12, and the metal tube 10 is subjected to an axial compressive force from the annular block 11.

[0080] Step 4: Under the combined action of the shock wave generated by the high-pressure plasma 20 and the extrusion force of the annular block 11, the axial length of the metal pipe 10 decreases, and the pipe wall of the metal pipe 10 bulges outward along the branch cavity of the split mold 29. The laser generator 3 continuously emits laser pulse beams 5 to impact the metal pipe 10 until the bulging branch reaches the specified length.

[0081] Step 5: Turn off the laser generator 3, disconnect the circuit of the resistance wire 22, remove the nut 16 of the spring 14, remove the pressure plate 12, spring 14 and ring block 11, open the split mold 29, and take out the tee pipe blank formed by the metal pipe fitting 10.

[0082] Step 6: Use wire cutting to cut off the closed end of the branch pipe of the tee pipe blank after the metal pipe fitting 10 is formed, and obtain the required tee pipe.

[0083] Example 2

[0084] like Figure 11 and12 As shown, this is another embodiment of the present invention. On the basis of Example 1, since the constraint layer uses high-phenyl silicone oil, when the laser pulse beam passes through the constraint layer to the absorption layer, a short-lived high-temperature and high-pressure plasma will be generated in the absorption layer. The high-temperature and high-pressure plasma will cause the high-phenyl silicone oil to undergo pyrolysis, producing a very small amount of volatiles.

[0085] High-phenyl silicone oil has excellent stability and long-term heat resistance. Its material structure is stable at high temperatures and is not easily decomposed. As the constraint layer, it can effectively prevent the generated high-pressure plasma from immediately volatilizing into the air, prolonging the action time of the high-pressure plasma and increasing the effect of the shock wave. Moreover, the extremely high optical transparency, excellent thermal and radiation stability, and extremely low volatility of high-phenyl silicone oil make it a key material with wide applications and outstanding characteristics in laser systems, optoelectronic packaging, and precision optical instruments.

[0086] Two groups of guiding holes are provided in the annular block 11, and a group of air blowing pipes 34 and a group of air suction pipes 35 are respectively installed, and both the air blowing pipes 34 and the air suction pipes 35 are located at the top of the constraint layer 19.

[0087] A protective shell 36 is fixedly installed at the bottom of the pressing plate 12. The inner diameter of the protective shell 36 is adapted to the outer diameter of the air blowing pipe 34 or the air suction pipe 35. A blowing circuit is provided outside the air blowing pipe 34, and a suction circuit is provided outside the air suction pipe 35. The blowing circuit at least includes a gas generator, a one-way valve, and a pressure regulating valve to discharge air through the air blowing pipe output; the suction circuit at least includes a negative pressure pump and a tail gas treatment device. The tail gas treatment device treats the collected volatiles and also detects the volatiles to judge whether harmful gases will be generated during the laser shock process, ensuring processing safety.

[0088] As Figure 12 shown, the height of the bottom of the output end of the air blowing pipe 34 from the top of the constraint layer 19 is a, and the height of the bottom of the output end of the air suction pipe 35 from the top of the constraint layer 19 is b, and a < b; air is blown at the lower position and discharged at the higher position.

[0089] In this embodiment, a group of air suction pipes is used to recover gas, and another group of air blowing pipes is used to discharge gas as quickly as possible. Discharging part of the gas is beneficial to enterprise production and reduces the content of volatiles in the device. Moreover, after the gas is discharged, the surface interference with the continuously working laser pulse beam can be effectively reduced.

[0090] Example 3

[0091] As <00s00223>and 14As shown, another embodiment of the present invention is provided. Based on embodiment 1, the blowing pipe 34 and the suction pipe 35 are connected together on the working plate 37, which is installed above the constraint layer. A light-transmitting hole is provided in the middle of the working plate 37, and a beam shaping mirror 38 is installed in the output direction of the impact head 7 to adjust the spot size and beam uniformity of the laser pulse beam 5, ensure the uniformity of the laser irradiation energy in the spot, and ensure that the laser pulse beam is concentrated and injected into the absorption layer at the bottom of the constraint layer through the light-transmitting hole, so as to avoid the branch pipe from becoming deformed and causing defective products.

[0092] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A metal tee tube bulging processing device based on laser shock wave, characterized in that, include: The workpiece mold system includes a split mold (29), which includes a symmetrical front mold (8) and a rear mold (9). After the front mold (8) and the rear mold (9) are closed, a vertical main pipe cavity (30) is provided in the middle. A metal pipe fitting (10) and a wedge-shaped concave seat (17) are installed in the main pipe cavity (30). The bottom of the metal pipe fitting (10) is inserted into the wedge-shaped concave seat (17). A branch pipe cavity (31) is provided in the lateral connection of the main pipe cavity (30). The branch pipe cavity (31) is used for the metal pipe fitting (10) to be heated and deformed into a tee pipe blank. A clamping device is installed on the top of the split mold (29). The component is used to press down from the end of the metal pipe (10); the metal pipe (10) is filled with a constraint layer (19), which is a transparent material with a high boiling point; an inclined concave surface (171) is provided on the top of the wedge-shaped concave seat (17), and the upper arc chord of the inclined concave surface (171) along the vertical section forms an inclination angle of 30º with the axial section; the inclined direction of the inclined concave surface (171) is set towards the branch cavity (31), and the focal point of the inclined concave surface (171) coincides with the bottom end of the center line of the branch cavity (31); an absorbent layer (18) is coated on the inclined concave surface (171) of the wedge-shaped concave seat (17). The light guiding system includes a laser generator (3) and a transmission device. The laser output by the laser generator (3) is transmitted into the main tube cavity (30) through the transmission device, and the direction of transmission is along the axial direction of the main tube cavity (30). The heating system includes a ceramic ring body with a resistance wire (22) inside; a half-set of annular grooves (32) are provided in the front half mold (8) and the rear half mold (9) outside the branch pipe cavity (31), and the ceramic ring body is installed in the fitted annular groove (32); a heating hole (28) is provided on the side of the annular groove (32) facing the main pipe cavity (30), and the heating hole (28) contacts the surface of the metal pipe fitting (10); The control system is used to control the opening and closing of the laser generator (3) and the output parameters, as well as the working parameters of the resistance wire (22).

2. The metal tee tube bulging processing device based on laser shock wave according to claim 1, characterized in that, A baffle (26) is installed on the same side of the front half mold (8) and the rear half mold (9), and multiple sets of bolts (27) are installed to connect the front half mold (8) and the rear half mold (9); the baffle (26) is used to laterally seal the annular groove (32). The bottoms of the front half mold (8), the rear half mold (9), and the wedge-shaped concave seat (17) are all constrained on the worktable (21).

3. The metal tee tube bulging processing device based on laser shock wave according to claim 1, characterized in that, The control system includes a computer (1) and a controller (2). Control information is input by the computer (1) and transmitted to the controller (2) to control the laser parameters emitted by the laser generator (3) and the working status of the resistance wire (22).

4. The metal tee tube bulging processing device based on laser shock wave according to claim 1, characterized in that, The transmission device includes a light guide tube (4), which is connected to the output end of the laser generator (3). The laser generator (3) emits a laser pulse beam (5) which is directed toward the total reflection mirror (6) mounted on the frame, forming a reflection and being injected into the main tube cavity (30) through the impact head (7) installed at the bottom. One end of the light guide tube (4) is connected to the laser generator (3), and the other end of the light guide tube (4) is connected to the impact head (7). The total reflection mirror (6) is installed in the light guide tube (4), and the output direction of the impact head (7) is along the axis of the metal tube (10) towards the upper end of the wedge-shaped concave seat (17) inclined concave surface (171), so that the laser pulse beam (5) is emitted from the laser generator (3) and irradiates the absorption layer (18) of the inclined concave surface (171) of the wedge-shaped concave seat (17) in sequence through the light guide tube (4), the total reflection mirror (6), and the impact head (7).

5. The metal tee tube bulging processing device based on laser shock wave according to claim 1, characterized in that, The clamping component includes a pressure plate (12), and an annular block (11) is provided on the side of the pressure plate (12) facing the main tube cavity (30); the annular block (11) and the pressure plate (12) are on the same central axis and have a through hole in the middle for the laser pulse beam (5) to pass through; the outer diameter of the annular block (11) is adapted to the inner diameter of the main tube cavity (30); the bottom of the annular block (11) abuts against the top of the metal pipe fitting (10); The top of the front half mold (8) and the rear half mold (9) are both equipped with double-headed studs (13). One end of the double-headed stud (13) is threaded to the corresponding front half mold (8) or rear half mold (9), and the other end passes through the pressure plate (12) and is sequentially equipped with a lower washer (1502), a spring (14) and an upper washer (1501), and is locked by a nut (16). The nut (16) is threaded onto the double-ended stud (13) and abuts against the upper washer (1501) downwards. The upper washer (1501) is forced to compress the spring (14) and the lower washer (1502), and compresses the pressure plate (12) to rise and fall along the axis of the main tube cavity (30).

6. The metal tee tube bulging processing device based on laser shock wave according to claim 5, characterized in that, When the laser pulse beam (5) passes through the confinement layer (19) and irradiates the absorption layer (18), the absorption layer (18) absorbs the energy of the laser and vaporizes and ionizes to form a high-pressure plasma (20). High-pressure plasma (20) squeezes metal pipe (10) and causes metal pipe (10) to deform along branch lumen (31).

7. The metal tee tube bulging processing device based on laser shock wave according to claim 5, characterized in that, The ceramic ring body also includes an inner ring ceramic seat (23), an outer ring ceramic seat (24) and an annular support block (25). The inner ring ceramic seat (23) and the outer ring ceramic seat (24) are both semi-circular rings. An arc-shaped groove is provided on the inner ring ceramic seat (23) facing the outer ring ceramic seat (24), and a resistance wire (22) is installed in the arc-shaped groove. The inner ring ceramic seat (23) and the outer ring ceramic seat (24) are stacked and fitted together. The baffle (26) uses bolts (27) to install the annular support block (25), the inner ring ceramic seat (23), and the outer ring ceramic seat (24) in the annular groove (32). The inner ring ceramic seat (23) is provided with multiple sets of circumferentially arranged heat-conducting holes (33) facing the heating hole (28); multiple sets of heating holes (28) are provided and arranged circumferentially, the angle between adjacent heating holes (28) is 10°, and the diameter is Φ1.5~Φ5 mm, and the heat-conducting holes (33) are connected to the heating holes (28).

8. The metal tee tube bulging processing device based on laser shock wave according to claim 7, characterized in that, Two sets of guide holes are provided in the annular block (11), and a set of air blowing pipes (34) and a set of air suction pipes (35) are installed respectively, and the air blowing pipes (34) and air suction pipes (35) are both located at the top of the constraint layer (19); A protective shell (36) is fixedly installed at the bottom of the pressure plate (12). The inner diameter of the protective shell (36) is adapted to the outer diameter of the blowing pipe (34) or the suction pipe (35). A blowing circuit is provided on the outside of the blowing pipe (34), and a suction circuit is provided on the outside of the suction pipe (35).

9. The metal tee tube bulging processing device based on laser shock wave according to claim 8, characterized in that, The blowing pipe (34) and the suction pipe (35) are connected together on the working plate (37), which is installed above the constraint layer (19). A light-transmitting hole is provided in the middle of the working plate (37), and a beam shaping mirror (38) is installed in the output direction of the impact head (7) to adjust the uniformity of the laser pulse beam (5) and improve the quality and efficiency of laser processing.

10. A bulging method for metal tee tubes based on laser shock wave technology, characterized in that... The specific steps of this method are as follows: Step 1: First, install the metal pipe fitting (10) to be processed into the cavity of the split mold (29); during installation, place the front half mold (8) and the rear half mold (9) on the worktable (21), and vertically install the wedge-shaped concave seat (17) in the main pipe cavity (30) of the front half mold (8) or the rear half mold (9). The upper end of the wedge-shaped concave seat (17) extends into the interior of the metal pipe fitting (10), and the stepped surface of the wedge-shaped concave seat (17) abuts against the lower end surface of the metal pipe fitting (10); the inclined concave surface (171) of the wedge-shaped concave seat (17) is coated with an absorbent layer (18), and the lower end surface of the annular block (11) abuts against the metal pipe. On the upper surface of the component (10), the pressure plate (12) is installed on the annular block (11), and the nut (16) is tightened to compress the spring (14); the front half mold (8) and the rear half mold (9) are closed and a ceramic ring is installed in the annular groove (32) so that the heat conduction hole (33) faces the heating hole (28); then the annular support block (25) is installed, and then the annular groove (32) is closed. The baffle (26) is fixed on the side of the front half mold (8) and the rear half mold (9) with bolts (27); then a high-boiling-point transparent substance is injected into the metal tube (10) as a constraint layer (19). Step 2: The resistance wire (22) heats the metal pipe (10) to raise the temperature at the heating position of the metal pipe (10) to the set temperature; the laser generator (3) emits a controlled laser pulse beam (5), which enters the interior of the metal pipe (10) along the axis and irradiates the absorption layer (18) of the inclined concave surface (171) of the wedge-shaped concave seat (17). After absorbing the energy of the laser, the absorption layer (18) vaporizes and ionizes to form a high-pressure plasma (20); the high-pressure plasma (20) rapidly expands outward to form a high-amplitude shock wave that propagates outward. The high-amplitude shock wave converges towards the concave focal point and applies radial shock wave pressure to the inner wall of the area where the branch pipe of the metal pipe (10) is located, causing the pipe wall of the metal pipe (10) to bulge outward along the branch pipe cavity (31); Step 3, synchronized with Step 2, the high-pressure plasma (20) applies radial pressure to the inner wall of the metal tube (10), while the compressed spring (14) applies a downward pressure to the pressure plate (12), and the metal tube (10) is subjected to axial extrusion force from the annular block (11); Step 4: Under the combined action of the shock wave generated by the high-pressure plasma (20) and the extrusion force of the annular block (11), the axial length of the metal pipe (10) decreases, and the pipe wall of the metal pipe (10) bulges outward along the branch cavity of the split mold (29). The laser generator (3) continuously emits laser pulse beams (5) to impact the metal pipe (10) until the bulging branch reaches the specified length. Step 5: Turn off the laser generator (3) and disconnect the resistance wire (22) circuit; remove the nut (16) of the spring (14), and remove the pressure plate (12), spring (14) and ring block (11); drain the liquid from the constraint layer (19), then open the split mold (29) and take out the tee blank after the metal pipe fitting (10) is formed; Step 6: Use wire cutting to cut off the closed end of the branch pipe of the tee pipe blank after the metal pipe fitting (10) is formed, and obtain the required metal tee pipe.

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