Pipe hydroforming two-stage pressurizing shaping device and method

Abstract

The invention relates to the field of metal pipe forming, in particular to a pipe hydroforming two-stage pressurization shaping device and method. The problems of large pressure value output capacity and large pressure fluctuation in a small pressure stage of existing supercharging equipment and method are solved. The device provided by the invention can meet the requirements of large pressure output capacity and small pressure value accurate control, and meets the requirement of pipe hydroforming. Only by manufacturing the two-stage pressurizing structure on the punch, the low-cost pressurizer with the small pressure output capacity can meet the requirement for large pressure in the shaping stage of the last stage of pipe hydroforming, and high-cost pressurizing equipment with the large output capacity is not needed. The device and the method are simple in structure and easy to implement.

Description

Technical Field

[0001] This invention relates to the field of metal pipe forming, and specifically to a two-stage pressurized forming device and method for pipe liquid filling forming. Background Technology

[0002] Aircraft contain complex, irregularly shaped tubular components with varying cross-sections. Due to their complexity, these components are often manufactured by forming segments and then welding them together. This manufacturing method not only involves numerous processes and high costs but also results in low reliability of the parts during service. Furthermore, the reliability of these components directly impacts the operational status of multiple systems.

[0003] To manufacture these parts with high quality and low cost, tubular liquid forming technology is increasingly being adopted. This technology involves injecting a liquid medium into the inside of a tube while applying a load to both ends or other parts of the tube. The combined pressure of the liquid medium and the external load forces the tube blank against the mold cavity, thus integrally forming a complex, irregularly shaped tube with a variable cross-section. For small features on irregularly shaped tubes (such as small fillets), the pressure of the liquid medium inside the tube needs to be significantly increased in the final forming stage for shaping. In the initial stage of forming, only a small pressure (excessive pressure will cause the tube blank to rupture and prevent further forming) combined with an external load is often sufficient to plastically deform the tube blank. Furthermore, the pressure cannot fluctuate significantly during this stage, as large pressure fluctuations can lead to wrinkling or rupture of the tube blank. In other words, the initial forming stage requires low pressure and precise control (approximately 10–20 MPa, with a pressure control accuracy of ±0.1 MPa), while the final shaping stage requires higher pressure, reaching 100–200 MPa, without the need for precise pressure control. The shaping stage, which only aims to form some small features, requires a high pressure level, necessitating the use of booster equipment with high pressure output capacity, resulting in high economic costs. Furthermore, booster equipment with high pressure output capacity exhibits significant pressure fluctuations at low pressures, easily leading to wrinkling or cracking of the tube blank. In other words, existing booster equipment and methods present a contradiction between high pressure output capacity and large pressure fluctuations at low pressure stages.

[0004] To address the contradiction between the existing pressurization equipment and methods, which have high pressure output capacity and large pressure fluctuations in the low pressure stage, as well as the high cost of using pressurization equipment with high output capacity for shaping, and to meet the requirements of low and precise pressure in the initial stage of pipe filling and high pressure in the shaping stage, it is necessary to develop a method and device that balances high pressure output capacity and precise control of low pressure values ​​at a low cost. Summary of the Invention

[0005] To address the contradiction between the high pressure output capacity and large pressure fluctuations in the low pressure stage of existing pressurization equipment and methods, as well as the high cost of using high-output pressurization equipment for shaping, this invention provides a two-stage pressurization and shaping device and method for pipe filling and shaping, which is key to the development of a dedicated device.

[0006] According to one aspect of this application, a two-stage pressurization shaping device for pipe filling and forming is provided, which consists of a mold (1), a left punch (2), a right punch (3), and a pressure unit (4);

[0007] The mold (1) includes an upper mold (1-1) and a lower mold (1-2), which together form the cavity of the tube blank (5) to be formed into the part;

[0008] The left punch (2) and right punch (3) are tools for achieving sealing at both ends of the tube blank (5) and applying axial pushing force;

[0009] The pressure unit (4) includes a booster body (4-1), a low-pressure sensor (4-2), a high-pressure sensor (4-3), a one-way valve (4-4), a solenoid on / off valve (4-5), and a pressure relief valve (4-6).

[0010] The left punch (2) includes a left punch rear section (2-1), a secondary pressure boosting pipeline connector (2-2), a left punch front section (2-3), a retaining ring (2-4), a secondary pressure boosting piston (2-5), and a sealing ring (2-6).

[0011] The rear section (2-1) of the left punch is generally presented as two cylindrical sections with different diameters. The smaller diameter section on the left is machined with external threads and can be connected to the side top cylinder of the liquid filling forming equipment. The other section on the right has a cylindrical cavity inside.

[0012] The front section (2-3) of the left punch is generally composed of three cylindrical sections with different diameters. The outer diameter of the left section is the same as that of the right side of the rear section (2-1) of the left punch, and the interior is also machined with a cylindrical cavity of the same diameter. The outer diameter of the middle part of the front section (2-3) of the left punch is the same as that of the tube blank to be formed. The diameter of the right side of the front section (2-3) of the left punch is 0.2 to 0.4 mm larger than the inner diameter of the tube blank (5).

[0013] The left punch front section (2-3) has a small diameter through hole machined in the center, and a sealing ring (2-6) is provided at the outlet of the through hole near the right side end;

[0014] The left punch front section (2-3) contains a secondary booster piston (2-5). The larger diameter end of the secondary booster piston (2-5) is located in the cylindrical cavity on the left side of the left punch front section (2-3) and has the same diameter. The smaller diameter end of the secondary booster piston (2-5) is located in the through hole at the center of the left punch front section (2-3) and both have the same diameter.

[0015] The retaining ring (2-4) is fixedly installed in the cylindrical cavity on the left side of the front section (2-3) of the left punch to limit the movement of the secondary booster piston (2-5);

[0016] The right side of the cylindrical cavity of the rear section (2-1) of the left punch has a through hole and is connected to a secondary pressure boosting pipe connector (2-2). The secondary pressure boosting pipe connector (2-2) is used to connect the pressure unit (4) and the left punch (2).

[0017] The right punch (3) includes a pressure medium pipeline connector (3-1), a right punch body (3-2), and a pressure medium channel (3-3). The right punch body (3-2) is generally in the form of three cylindrical sections. The right side section is machined with external threads and can be connected to the side top cylinder of the liquid filling forming equipment. The outer diameter of the middle section is the same as the outer diameter of the tube blank to be formed. The diameter of the left side section is 0.2 to 0.4 mm larger than the inner diameter of the tube blank (5).

[0018] The right punch body (3-2) has a pressure medium channel (3-3) machined in the center and is connected to the pressure unit (4) through a pressure medium pipeline connector (3-1).

[0019] The assembly method of the left punch (2) is as follows: place the sealing ring (2-6) at the outlet of the through hole on the front section (2-3) of the left punch, insert the smaller diameter end of the secondary booster piston (2-5) into the through hole on the front section (2-3) of the left punch, and then fix the retaining ring (2-4) in the cylindrical cavity on the left side of the front section (2-3) of the left punch to block the secondary booster piston (2-5). Then fix the right side of the rear section (2-1) of the left punch and the left side of the front section (2-3) of the left punch into a whole. The retaining ring (2-4) can be fixedly installed by threaded connection, welding, etc., and the connection method between the rear section (2-1) of the left punch and the front section (2-3) of the left punch can be threaded connection, welding, etc.

[0020] The booster body (4-1) is a device for boosting the pressure medium to a maximum pressure of 20-50 MPa;

[0021] The low-pressure sensor (4-2) is located at the pressure output port of the booster body (4-1). The low-pressure sensor (4-2) is a pressure sensor with a range that matches the maximum output pressure of the booster body (4-1) and has high accuracy. It is used to measure the pressure in the initial stage of pipe filling and forming.

[0022] The high-pressure sensor (4-3) is a pressure sensor with general accuracy that is matched with the maximum pressure at the end of the pipe filling and forming stage. It is used to measure the pressure at the end of the pipe filling and forming stage.

[0023] The one-way valve (4-4) is connected to the pipeline between the booster body (4-1) and the right punch (3) to ensure that the pressure medium flows unidirectionally from the booster body (4-1) to the right punch (3);

[0024] A pressure relief valve (4-6) is installed on the pipeline between the one-way valve (4-4) and the right punch (3);

[0025] The electromagnetic on / off valve (4-5) is connected to the pipeline between the booster body (4-1) and the left punch (2);

[0026] The high-pressure sensor (4-3) is installed on the pipeline between the one-way valve (4-4) and the right punch (3).

[0027] The cross-sectional shape of the left punch (2) and the right punch (3) is designed as an irregular cross-section, which can be used for liquid filling and forming of irregular cross-section pipes with secondary pressurization.

[0028] A return spring (2-7) is provided between the larger diameter end of the secondary booster piston (2-5) and the right side wall of the cylindrical cavity on the front section (2-3) of the left punch;

[0029] The return spring (2-7) is in a compressed state. After the secondary booster piston (2-5) finishes its forward operation, the return spring (2-7) returns to the retaining ring (2-4) under the action of the spring force.

[0030] According to another aspect of this application, a two-stage pressure-boosting shaping method for pipe filling and forming is provided, which employs the above-mentioned two-stage pressure-boosting shaping device for pipe filling and forming.

[0031] Includes the following steps:

[0032] Step 1: Shaping preparation;

[0033] Manufacture and configure the required equipment according to the above-mentioned equipment, and cut a certain length of pipe section to make a pipe blank according to the process requirements of the target part (5);

[0034] Step 2: Initial Formation;

[0035] Open the upper mold (1-1) and place the tube blank (5) in the cavity of the lower mold (1-2). The upper mold (1-1) and the lower mold (1-2) close the mold. The left punch (2) and the right punch (3) are inserted into the two ends of the tube blank (5) respectively to achieve end sealing and provide axial pushing force for the tube blank (5). The pressure medium output by the booster body (4-1) flows to the right punch (3) and into the tube blank (5) through the pressure medium channel (3-3). The electromagnetic on / off valve (4-5) is in the closed state. The low pressure sensor (4-2) detects the real-time pressure value of the tube blank (5) during forming and feeds it back to the control system of the equipment used to regulate the pressure. According to the set process parameters, the tube blank (5) is initially formed under the action of the left punch (2), the right punch (3) and the pressure medium.

[0036] Step 3: Shaping and shaping stage;

[0037] Open the solenoid on / off valve (4-5) to allow the pressure medium to flow into the left punch (2). The pressure medium pushes the secondary booster piston (2-5) forward so that its smaller diameter end enters the tube blank (5). The pressure medium is compressed, which increases the pressure. Since the pressure in the tube blank (5) is higher than the output pressure of the booster body (4-1), the check valve (4-4) closes. As the secondary booster piston (2-5) continues to move forward, the pressure in the tube blank (5) continues to rise, thus achieving the pressure required for tube blank shaping.

[0038] Step 4: Remove the load after forming is complete;

[0039] After the forming is completed, the booster body (4-1) stops outputting pressure medium, opens the pressure relief valve (4-6) to release the pressure in the tube blank (5) and remove the pressure medium, and the secondary booster piston (2-5) returns to the retaining ring (2-4) manually or under the action of the return spring.

[0040] Step 5: Open the mold and remove the parts;

[0041] After opening the upper mold (1-1), remove the formed part and restore the punch, solenoid valve, etc. to their initial state to wait for the next forming.

[0042] In step two, the parameters and parameter matching relationships of the left punch (2), right punch (3) and internal pressure can be obtained through simulation analysis or multiple experiments.

[0043] The tube blank (5) can be made of materials such as 5B02 aluminum alloy, TA18 titanium alloy, 2169 stainless steel, and 6061 aluminum alloy tube.

[0044] The formed part can be a multi-port pipe part, and punches can be added according to the number of branches of the multi-port pipe.

[0045] The beneficial effects of this invention are:

[0046] (1) The device proposed in this invention can take into account both the need for high pressure output capacity and the need for precise control of low pressure value, thus meeting the needs of pipe filling and forming.

[0047] (2) The present invention only requires the creation of a two-stage pressure boosting structure on the punch to meet the high pressure requirements of the final shaping stage of pipe filling and forming with a low-cost booster with a relatively small output pressure capacity, without the need for high-cost, high-output-capacity booster equipment.

[0048] (3) The device and method described in this invention have a simple structure and are easy to implement. Attached Figure Description

[0049] Figure 1 Isometric drawing of the secondary booster shaping device;

[0050] Figure 2 This is a front view of the main body of the secondary booster shaping device;

[0051] Figure 3 Left view of the main body of the secondary booster shaping device;

[0052] Figure 4 for Figure 3 A sectional view along line AA.

[0053] Figure 5 This is a cross-sectional view of the left punch.

[0054] Figure 6 This is a cross-sectional view of the left punch with a return spring.

[0055] Among them, 1 is the mold, 1-1 is the upper mold, and 1-2 is the lower mold; 2 is the left punch, 2-1 is the rear section of the left punch, 2-2 is the secondary pressure boosting pipeline connector, 2-3 is the front section of the left punch, 2-4 is the retaining ring, 2-5 is the secondary pressure boosting piston, 2-6 is the sealing ring, 2-7 is the return spring, 3 is the right punch, 3-1 is the pressure medium pipeline connector, 3-2 is the right punch body, 3-3 is the pressure medium channel, 4 is the pressure unit, 4-1 is the booster body, 4-2 is the low-pressure sensor, 4-3 is the high-pressure sensor, 4-4 is the one-way valve, 4-5 is the electromagnetic on / off valve, 4-6 is the pressure relief valve, and 5 is the tube blank. Detailed Implementation

[0056] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0057] Example 1

[0058] The target part is a large cross-section differential reducer pipe, made of 1Cr18Ni10Ti, with a thickness of 1.5mm, an initial pipe diameter of 36mm, an outer diameter of 50mm for the reducer section, a total sample length of 200mm, and a reducer section length of 80mm.

[0059] Step 1: Forming Preparation. Design and manufacture the upper and lower molds according to the target part. Configure the left punch, right punch, and pressure unit according to the device described in this invention. Cut a 260mm long pipe section to form the pipe blank 5 according to the process requirements of the target part.

[0060] Step 2: Initial Forming Stage. Open the upper mold 1-1 and place the tube blank 5 into the cavity of the lower mold 1-2. The upper mold 1-1 and the lower mold 1-2 are closed and a clamping force of 120 tons is applied. The left punch 2 and the right punch 3 are inserted into both ends of the tube blank 5 to achieve end sealing and provide axial pushing force for the tube blank 5. The pressure medium (water-based emulsion) output by the pressure booster body 4-1 flows to the right punch 3 and into the tube blank 5 through the pressure medium channel 3-3. The electromagnetic on / off valve 4-5 is in the closed state. The low-pressure sensor 4-2 detects the real-time pressure value of the tube blank 5 during forming and feeds it back to the control system of the equipment used to regulate the pressure. The feed amount of the left punch 2 and the right punch 3 is 20mm, and the maximum pressure medium reaches 45MPa, realizing the initial forming of the tube blank 5.

[0061] Step 3: Shaping Stage. Left punch 2 and right punch 3 cease feeding. The solenoid on / off valve 4-5 opens, allowing the pressure medium to flow into left punch 2. The pressure medium pushes the secondary booster piston 2-5 forward, causing its smaller diameter end to enter the tube blank 5. The compressed pressure medium increases the pressure. Since the pressure in tube blank 5 is higher than the output pressure of the booster body 4-1, the one-way valve 4-4 closes. As the secondary booster piston 2-5 continues to advance, the pressure in tube blank 5 continuously rises to 126 MPa, completing the shaping process.

[0062] Step 4: Releasing the load after forming. After forming is complete, the intensifier body 4-1 stops outputting pressure medium, opens the pressure relief valve 4-6 to release the pressure in the tube blank 5 and remove the pressure medium, and the secondary intensifier piston 2-5 returns to the retaining ring 2-4 manually or under the action of the return spring.

[0063] Step 5: Mold Opening and Part Removal. After opening the upper mold 1-1, remove the formed part and restore the punch, solenoid valve, etc. to their initial state to await the next forming.

[0064] In step two, the parameters and parameter matching relationships of the left punch 2, the right punch 3, and the internal pressure can be obtained through simulation analysis or multiple experiments.

[0065] The specific methods for obtaining it are as follows:

[0066] (1) Calculate the minimum internal pressure required for the pipe of this specification to undergo plastic deformation, i.e., the initial yield internal pressure P. s :

[0067] P s =2σ s *t / D

[0068] In the formula, σs The yield strength of the pipe is 350 MPa, which can be measured by uniaxial tensile test in this embodiment. t is the pipe wall thickness and D is the original pipe outer diameter.

[0069] The initial yield internal pressure P was calculated. s It is 29.1667 MPa.

[0070] (2) Set an initial internal pressure and design the increase of the internal pressure as the punch feeds axially:

[0071] The initial internal pressure is set to 1.0, 1.2, 1.4, and 1.6 times the initial yield internal pressure P. s The increment of the axial feed displacement S of the punch is set to 0, 0.1S, 0.3S, and 0.5S.

[0072] Simulations or experiments are conducted based on the set parameters. By analyzing the simulation and experimental results, indicators such as premature pipe breakage or wrinkling are observed to determine the optimal matching relationship between the punch displacement and internal pressure parameters. In this embodiment, the optimal parameter is 1.2P. s The increase was 0.5S.

[0073] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions made by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A two-stage pressurization and shaping device for pipe filling and forming, characterized in that, It consists of a mold (1), a left punch (2), a right punch (3), and a pressure unit (4); The mold (1) includes an upper mold (1-1) and a lower mold (1-2), which together form the cavity of the tube blank (5) to be formed into the part; The left punch (2) and right punch (3) are tools for achieving sealing at both ends of the tube blank (5) and applying axial pushing force; The pressure unit (4) includes a booster body (4-1), a low-pressure sensor (4-2), a high-pressure sensor (4-3), a one-way valve (4-4), a solenoid on / off valve (4-5), and a pressure relief valve (4-6).

2. The pipe filling and forming two-stage pressurization and shaping device according to claim 1, characterized in that, The left punch (2) includes a left punch rear section (2-1), a secondary pressure boosting pipeline connector (2-2), a left punch front section (2-3), a retaining ring (2-4), a secondary pressure boosting piston (2-5), and a sealing ring (2-6).

3. The two-stage pressurization and shaping device for pipe filling and forming according to claim 2, characterized in that, The rear section (2-1) of the left punch is generally presented as two cylindrical sections with different diameters. The smaller diameter section on the left is machined with external threads and can be connected to the side top cylinder of the liquid filling forming equipment. The other section on the right has a cylindrical cavity inside. The front section (2-3) of the left punch is generally composed of three cylindrical sections with different diameters. The outer diameter of the left section is the same as that of the right side of the rear section (2-1) of the left punch, and the interior is also machined with a cylindrical cavity of the same diameter. The outer diameter of the middle part of the front section (2-3) of the left punch is the same as that of the tube blank to be formed. The diameter of the right side of the front section (2-3) of the left punch is 0.2 to 0.4 mm larger than the inner diameter of the tube blank (5). The left punch front section (2-3) has a small diameter through hole machined in the center, and a sealing ring (2-6) is provided at the outlet of the through hole near the right side. The left punch front section (2-3) contains a secondary booster piston (2-5). The larger diameter end of the secondary booster piston (2-5) is located in the cylindrical cavity on the left side of the left punch front section (2-3) and has the same diameter. The smaller diameter end of the secondary booster piston (2-5) is located in the through hole at the center of the left punch front section (2-3) and both have the same diameter. The retaining ring (2-4) is fixedly installed in the cylindrical cavity on the left side of the front section (2-3) of the left punch to limit the movement of the secondary booster piston (2-5); The right side of the cylindrical cavity of the rear section (2-1) of the left punch has a through hole and is connected to a secondary pressure boosting pipe connector (2-2). The secondary pressure boosting pipe connector (2-2) is used to connect the pressure unit (4) and the left punch (2). The right punch (3) includes a pressure medium pipeline connector (3-1), a right punch body (3-2), and a pressure medium channel (3-3). The right punch body (3-2) is generally in the form of three cylindrical sections. The right side section is machined with external threads and can be connected to the side top cylinder of the liquid filling forming equipment. The outer diameter of the middle section is the same as the outer diameter of the tube blank to be formed. The diameter of the left side section is 0.2 to 0.4 mm larger than the inner diameter of the tube blank (5). The right punch body (3-2) has a pressure medium channel (3-3) machined in the center and is connected to the pressure unit (4) through a pressure medium pipeline connector (3-1).

4. The two-stage pressurization and shaping device for pipe filling and forming according to claim 3, characterized in that, The assembly method of the left punch (2) is as follows: place the sealing ring (2-6) at the outlet of the through hole on the front section (2-3) of the left punch, insert the smaller diameter end of the secondary booster piston (2-5) into the through hole on the front section (2-3) of the left punch, and then fix the retaining ring (2-4) in the cylindrical cavity on the left side of the front section (2-3) of the left punch to block the secondary booster piston (2-5). Then fix the right side of the rear section (2-1) of the left punch and the left side of the front section (2-3) of the left punch into a whole. The retaining ring (2-4) can be fixedly installed by threaded connection, welding, etc., and the connection method between the rear section (2-1) of the left punch and the front section (2-3) of the left punch can be threaded connection, welding, etc.

5. The two-stage pressurization and shaping device for pipe filling and forming according to claim 4, characterized in that, The booster body (4-1) is a device for boosting the pressure medium to a maximum pressure of 20-50 MPa; The low-pressure sensor (4-2) is located at the pressure output port of the booster body (4-1). The low-pressure sensor (4-2) is a pressure sensor with a range that matches the maximum output pressure of the booster body (4-1) and has high accuracy. It is used to measure the pressure in the initial stage of pipe filling and forming. The high-pressure sensor (4-3) is a pressure sensor with general accuracy that is matched with the maximum pressure at the end of the pipe filling and forming stage. It is used to measure the pressure at the end of the pipe filling and forming stage. The one-way valve (4-4) is connected to the pipeline between the booster body (4-1) and the right punch (3) to ensure that the pressure medium flows unidirectionally from the booster body (4-1) to the right punch (3); A pressure relief valve (4-6) is installed on the pipeline between the one-way valve (4-4) and the right punch (3); The electromagnetic on / off valve (4-5) is connected to the pipeline between the booster body (4-1) and the left punch (2); The high-pressure sensor (4-3) is installed on the pipeline between the one-way valve (4-4) and the right punch (3).

6. The two-stage pressurization and shaping device for pipe filling and forming according to claim 5, characterized in that, The cross-sectional shape of the left punch (2) and the right punch (3) is designed as an irregular cross-section, which can be used for liquid filling and forming of irregular cross-section pipes with secondary pressurization.

7. The two-stage pressurization and shaping device for pipe filling and forming according to claim 6, characterized in that, A return spring (2-7) is provided between the larger diameter end of the secondary booster piston (2-5) and the right side wall of the cylindrical cavity on the front section (2-3) of the left punch; The return spring (2-7) is in a compressed state. After the secondary booster piston (2-5) finishes its forward operation, the return spring (2-7) returns to the retaining ring (2-4) under the action of the spring force.

8. A two-stage pressurization and shaping method for pipe forming, characterized in that, The pipe filling and forming two-stage pressurization shaping device according to any one of claims 1 to 7 is adopted; Includes the following steps: Step 1: Shaping preparation; Manufacture and configure the required equipment according to the above-mentioned equipment, and cut a certain length of pipe section to make a pipe blank according to the process requirements of the target part (5); Step 2: Initial Formation; Open the upper mold (1-1) and place the tube blank (5) in the cavity of the lower mold (1-2). The upper mold (1-1) and the lower mold (1-2) close the mold. The left punch (2) and the right punch (3) are inserted into the two ends of the tube blank (5) respectively to achieve end sealing and provide axial pushing force for the tube blank (5). The pressure medium output by the booster body (4-1) flows to the right punch (3) and into the tube blank (5) through the pressure medium channel (3-3). The electromagnetic on / off valve (4-5) is in the closed state. The low pressure sensor (4-2) detects the real-time pressure value of the tube blank (5) during forming and feeds it back to the control system of the equipment used to regulate the pressure. According to the set process parameters, the tube blank (5) is initially formed under the action of the left punch (2), the right punch (3) and the pressure medium. Step 3: Shaping and shaping stage; Open the solenoid on / off valve (4-5) to allow the pressure medium to flow into the left punch (2). The pressure medium pushes the secondary booster piston (2-5) forward so that its smaller diameter end enters the tube blank (5). The pressure medium is compressed, which increases the pressure. Since the pressure in the tube blank (5) is higher than the output pressure of the booster body (4-1), the check valve (4-4) closes. As the secondary booster piston (2-5) continues to move forward, the pressure in the tube blank (5) continues to rise, thus achieving the pressure required for tube blank shaping. Step 4: Remove the load after forming is complete; After the forming is completed, the booster body (4-1) stops outputting pressure medium, opens the pressure relief valve (4-6) to release the pressure in the tube blank (5) and remove the pressure medium, and the secondary booster piston (2-5) returns to the retaining ring (2-4) manually or under the action of the return spring. Step 5: Open the mold and remove the parts; After opening the upper mold (1-1), remove the formed part and restore the punch, solenoid valve, etc. to their initial state to await the next forming.

9. The two-stage pressurization and shaping method for pipe filling and forming according to claim 8, characterized in that, In step two, the parameters and parameter matching relationships of the left punch (2), right punch (3) and internal pressure can be obtained through simulation analysis or multiple experiments.

10. The two-stage pressurization and shaping method for pipe filling and forming according to claim 9, characterized in that, The tube blank (5) can be made of materials such as 5B02 aluminum alloy, TA18 titanium alloy, 2169 stainless steel, and 6061 aluminum alloy tube. The formed part can be a multi-port pipe part, and punches can be added according to the number of branches of the multi-port pipe.

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