A one-mold two-piece forming device and method for titanium alloy large-diameter and small-width seals

Abstract

The present invention discloses a one-mold two-piece forming device and method for titanium alloy large-diameter and small-width seals, wherein the upper push plate and the lower push plate are respectively connected to the upper platform and the lower platform of the hydraulic press and are fixed by a mechanical device; the upper electrode and the upper electrode auxiliary block are connected to the upper push plate, and the lower electrode and the lower electrode auxiliary block are connected to the lower push plate; the uniform and rapid heating of the titanium alloy large-diameter tube blank is achieved, the uniformity of the forming process is ensured, and the device is suitable for the forming of titanium alloy thin-walled annular components of different thicknesses; through the design of a split-flap rigid mold, the advantages of split-flap mold stamping forming and air expansion forming can be combined, the forming cycle can be effectively shortened, and the forming efficiency can be improved; the one-mold two-piece forming concept can effectively improve the forming efficiency, improve material utilization, and reduce production costs.

Description

Technical Field

[0001] The present invention relates to the field of structural design and application technology for precision forming of titanium alloy thin-walled components, and in particular provides a one-mold two-piece forming device and method for titanium alloy large-diameter and small-width seals. Background Art

[0002] Titanium alloy large-diameter annular sealing thin-walled components are important structural components of the cooling air circulation system of advanced aircraft engines. After forming, they need to be precisely welded and assembled with other components, which places strict demands on their forming accuracy. Considering that titanium alloys usually have a large amount of springback when formed at room temperature, and the large diameter puts forward dimensional requirements for hot forming heating furnaces, the current only way to achieve precise processing of such parts is to use a combination of petal hot forming and local welding. However, this method has a complex forming process, poor integrity of the formed parts, a long forming cycle, a short mold life, and high energy consumption, resulting in high production costs per piece.

[0003] In addition, a current-assisted hot forming technology that uses the Joule heating effect and electroplastic effect generated by pulsed current passing through metal to achieve rapid heating and high-quality forming of thin-walled components has been applied to the forming of titanium alloy pipe parts. However, unlike thin-walled pipe parts with small diameters and long lengths, titanium alloy ring-type sealing components have large diameters and short lengths. Therefore, they are affected by the lower temperature at the electrode clamping point, resulting in a smaller uniform area when the parts are heated. If a single part is formed, the material utilization rate will be reduced. On the other hand, the process method of using high-pressure gas to provide forming force is limited by operational safety and equipment reliability, and the gas pressure is usually low, resulting in a slower forming process and lower forming efficiency, which limits the mass production of such parts.

[0004] People are eager to obtain a one-mold two-piece forming device and method for titanium alloy large-diameter and small-width seals with excellent technical effects. Summary of the Invention

[0005] The purpose of the present invention is to provide a one-mold two-piece forming device and method for titanium alloy large-diameter and small-width seals with excellent technical effects. The large diameter is about 1m, and the small width is less than 0.3m. In view of the difficulties that titanium alloy large-diameter and small-width U-shaped, M-shaped and other seals can only adopt segmented forming-local welding process due to the size limitation of the heating furnace in the existing hot forming process, resulting in complex forming process, poor integrity of formed parts, high production cost, and the slow forming process of current-assisted pneumatic forming technology due to low pneumatic pressure, it is proposed to adopt a rigid-flexible one-mold two-piece efficient forming method based on current-assisted technology, so as to achieve high-quality and precise forming of titanium alloy large-diameter and small-width U-shaped, M-shaped and other thin-walled seals.

[0006] The one-mold two-piece forming device for titanium alloy large-diameter and small-width seals includes: a hydraulic press, an upper push plate, an upper push plate insulating layer, an upper electrode, an upper electrode auxiliary block, an upper sealing ring, a die, a die insulating layer, a split die positioning spring, a split die, a split die tightening spring, a split die insulating layer, a lower push plate, a lower push plate insulating layer, a lower electrode, a lower electrode auxiliary block, a lower sealing ring, a temperature measuring thermocouple, an upper spring, a lower spring, a high-pressure gas inlet, and a power supply; wherein, the upper push plate and the lower push plate are respectively connected to the upper platform and the lower platform of the hydraulic press connected and fixed by a mechanical device; the upper electrode and the upper electrode auxiliary block are connected to the upper push plate, and the lower electrode and the lower electrode auxiliary block are connected to the lower push plate; an upper push plate insulating layer is provided between the upper push plate and the upper electrode and the upper electrode auxiliary block, and a lower push plate insulating layer is provided between the lower push plate and the lower electrode and the lower electrode auxiliary block, and the upper push plate insulating layer and the lower push plate insulating layer are formed by surface treatment at the parts where the upper push plate and the lower push plate contact the upper electrode, the upper electrode auxiliary block, the lower electrode and the lower electrode auxiliary block, so as to play an insulating and heat-insulating role; The upper sealing ring and the lower sealing ring are respectively placed in the grooves in the upper push plate and the lower push plate to achieve sealing with the forming cylinder blank; the split mold is connected to the upper push plate through the split mold positioning spring and fixed in the corresponding spatial position, and the split mold has a built-in split mold tightening spring to achieve the split mold tightening action; the inner surface of the female mold and the outer surface of the split mold are respectively provided with a female mold insulation layer and a split mold insulation layer at the parts in contact with the forming cylinder blank, which play an insulating and heat-insulating role through surface treatment; the upper end and the lower end of the female mold are respectively The upper spring and the lower spring are connected to the upper push plate and the lower push plate, and the die can be opened in half along the center line. The die can move in the vertical direction as the upper spring and the lower spring are compressed and relaxed, and the die can be opened in half; the upper electrode and the lower electrode are multiple groups, and each group of electrodes is arranged correspondingly up and down. The upper electrode, the lower electrode and the power supply are electrically connected, the upper electrode is connected to the corresponding positive pole of the power supply, and the lower electrode is connected to the corresponding negative pole of the power supply. A high-pressure gas inlet is provided in the vertical direction of the upper push plate, and a temperature measuring thermocouple is located in the through hole of the die.

[0007] The method for forming a titanium alloy large-diameter and small-width seal with one mold and two pieces comprises the following specific steps:

[0008] Step 1: cutting the titanium alloy slab according to the size of the titanium alloy thin-walled sealing component, rolling the titanium alloy slab into a cylinder and welding it into a formed cylinder blank;

[0009] Step 2: Perform insulation coating between the upper push plate and the upper electrode and the upper electrode auxiliary block, perform insulation coating between the lower push plate and the lower electrode and the lower electrode auxiliary block, and perform insulation coating on the inner surface of the die and the outer surface of the split die in contact with the forming cylinder. The coating thickness is 10µm~500µm;

[0010] Step 3: Install the upper push plate and the lower push plate on the upper and lower platforms of the hydraulic press respectively, and then install the split die positioning spring, split die, split die tightening spring, upper sealing ring, lower sealing ring, upper electrode auxiliary block and lower electrode auxiliary block, forming cylinder, upper spring, concave die, lower spring, upper electrode and lower electrode;

[0011] Step 4: Connect each set of upper electrodes and lower electrodes to the corresponding power supply;

[0012] Step 5: Turn on the power supply and gradually increase the current density until the temperature of the forming tube reaches 700℃~950℃ and then keep it warm for 1min~3min;

[0013] Step 6: Start the hydraulic press, move the upper push plate downward, and open the split die to plastically deform the formed cylinder along the shape of the concave die and the split die;

[0014] Step 7: When the upper push plate reaches the forming position, positive pressure gas is filled in. The gas pressure is less than 10MPa and the temperature and pressure are kept constant for 10min~30min.

[0015] Step 8: Gradually reduce the current value until it reaches zero, turn off the power, unload the air pressure, lift the upper push plate, and retract the split mold;

[0016] Step 9: Open the die, take out the formed tube blank, and cut the formed tube blank into two independent formed parts.

[0017] The one-mold two-piece forming device and method for titanium alloy large-diameter and small-width seals addresses the shortcomings of existing forming technologies for titanium alloy large-diameter and small-width U-shaped, M-shaped and other seals, and proposes using pulse current to pass through metal to generate Joule heating effect to achieve efficient heating of the forming plate blank; then adopts a one-mold two-piece design concept, and combines the high efficiency advantages of split-die stamping forming and the precision forming characteristics of air expansion forming to achieve high-quality and precise forming of titanium alloy large-diameter and small-width U-shaped, M-shaped and other thin-walled seals.

[0018] The one-mold two-piece forming device and method for titanium alloy large-diameter and small-width seals realizes uniform and rapid heating of titanium alloy large-diameter cylindrical blanks, ensures the uniformity of the forming process, and is suitable for the forming of titanium alloy thin-walled annular components of different thicknesses; through the design of a split-flap rigid mold, the advantages of split-flap mold stamping and inflation forming can be combined to effectively shorten the forming cycle and improve the forming efficiency; the one-mold two-piece forming concept can effectively improve the forming efficiency, increase material utilization, and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0020] Figure 1Schematic diagram of a one-mold two-piece forming device for titanium alloy large-diameter and small-width seals;

[0021] Figure 2 It is a schematic diagram of the forming device before forming;

[0022] Figure 3 Schematic diagram of the forming device after mold closing.

[0023] In the figure: 1 upper push plate, 2 upper push plate insulating layer, 3 upper electrode auxiliary block, 4 upper electrode, 5 upper sealing ring, 6 cavity die, 7 cavity die insulating layer, 8 split die positioning spring, 9 split die, 10 split die tightening spring, 11 split die insulating layer, 12 lower push plate, 13 lower push plate insulating layer, 14 lower electrode auxiliary block, 15 lower electrode, 16 lower sealing ring, 17 temperature measuring thermocouple, 18 upper spring, 19 lower spring, 20 high-pressure gas inlet, 21 forming tube blank. DETAILED DESCRIPTION

[0024] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of the specific embodiments of the present invention. However, the specific embodiments of the present invention described herein are only for the purpose of explaining the present invention and are not to be construed as limiting the present invention in any way. Based on the teachings of the present invention, a skilled person can conceive of any possible variations based on the present invention, and such variations should be considered to fall within the scope of the present invention.

[0025] Example 1

[0026] The one-mold two-piece forming device for titanium alloy large-diameter and small-width seals includes: a hydraulic press, an upper push plate 1, an upper push plate insulating layer 2, an upper electrode 4, an upper electrode auxiliary block 3, an upper sealing ring 5, a die 6, a die insulating layer 7, a split die positioning spring 8, a split die 9, a split die tightening spring 10, a split die insulating layer 11, a lower push plate 12, a lower push plate insulating layer 13, a lower electrode 15, a lower electrode auxiliary block 14, a lower sealing ring 16, a temperature measuring thermocouple 17, an upper spring 18, a lower spring 19, a high-pressure gas inlet 20, and a power supply; wherein, the upper push plate 1 and the lower push plate 12 are respectively connected to the upper plane of the hydraulic press The platform is connected to the lower platform and fixed by a mechanical device; the upper electrode 4 is connected to the upper electrode auxiliary block 3 and the upper push plate 1, and the lower electrode 15 is connected to the lower electrode auxiliary block 14 and the lower push plate 12; an upper push plate insulating layer 2 is provided between the upper push plate 1 and the upper electrode 4 and the upper electrode auxiliary block 3, and a lower push plate insulating layer 13 is provided between the lower push plate 12 and the lower electrode 15 and the lower electrode auxiliary block 14, and the upper push plate insulating layer 2 and the lower push plate insulating layer 13 are the parts where the upper push plate 1 and the lower push plate 12 contact with the upper electrode 4, the upper electrode auxiliary block 3, the lower electrode 15 and the lower electrode auxiliary block 14 through surface treatment , which plays an insulating and heat-insulating role; the upper sealing ring 5 and the lower sealing ring 16 are respectively placed in the grooves in the upper push plate 1 and the lower push plate 12, which play a role in sealing with the forming cylinder blank; the split mold 9 is connected to the upper push plate 1 through the split mold positioning spring 8, and fixed in the corresponding spatial position, and the split mold 9 has a built-in split mold tightening spring 10 to realize the tightening action of the split mold 9; the inner surface of the female mold 6 and the outer surface of the split mold 9 are respectively provided with a female mold insulation layer 7 and a split mold insulation layer 11 at the parts in contact with the forming cylinder blank 21, which play an insulating and heat-insulating role through surface treatment; the upper and lower ends of the female mold 6 are respectively The upper push plate 1 and the lower push plate 12 are connected through the upper spring 18 and the lower spring 19, and the die 6 can be opened in half along the center line. The die 6 can move in the vertical direction as the upper spring 18 and the lower spring 19 are compressed and relaxed, and the die 6 can be opened in half; the upper electrode 4 and the lower electrode 15 are multiple groups, and each group of electrodes is arranged correspondingly up and down. The upper electrode 4 and the lower electrode 15 are electrically connected to the power supply, the upper electrode is connected to the corresponding positive pole of the power supply, and the lower electrode is connected to the corresponding negative pole of the power supply. The upper push plate 1 is vertically provided with a high-pressure gas inlet 20, and the temperature measuring thermocouple 17 is located in the through hole of the die 6.

[0027] The steps of the one-mold two-piece forming method of the titanium alloy large-diameter and small-width seal are as follows:

[0028] Step 1: According to the size of the titanium alloy thin-walled sealing component, the titanium alloy slab is cut by laser cutting, and then the cylinder blank is roll-bent and welded to form the titanium alloy forming cylinder blank 21 required for forming. Lubricant is sprayed on the non-clamping areas of the inner and outer surfaces of the forming cylinder blank 21;

[0029] Step 2: Perform insulation coating between the upper push plate 1 and the upper electrode 4 and the upper electrode auxiliary block 3, perform insulation coating between the lower push plate 12 and the lower electrode 15 and the lower electrode auxiliary block 14, and perform insulation coating on the inner surface of the die 6 and the outer surface of the split die 9 in contact with the forming cylinder 21. By controlling the processing parameters, the thickness of each part is uniform, and the coating thickness is between 50µm and 300µm.

[0030] Step 3: Install the upper push plate 1 and the lower push plate 12 on the upper and lower platforms of the hydraulic press respectively, and fix them through T-slots and fastening bolts, and ensure that the positions of the upper push plate 1 and the lower push plate 12 correspond to each other; install the upper sealing ring 5, the upper electrode auxiliary block 3, the split mold positioning spring 8, the split mold tightening spring 10, the split mold 9, the lower sealing ring 16, the lower electrode auxiliary block 14 in sequence, and then install the forming cylinder 21, the upper spring 18, the die 6, and the lower spring 19. The relative positions of each forming device are as follows: Figure 2 As shown;

[0031] Step 4: Install the upper electrode 4 and the lower electrode 15 respectively, and there is a certain pressing force between the electrodes, the forming cylinder 21 and the electrode auxiliary block to ensure that no sparking occurs during the power-on process. Then, connect each set of upper electrodes 4 and lower electrodes 15 to an independent power supply, with the upper electrode 4 connected to the positive pole of the power supply and the lower electrode 15 connected to the negative pole of the power supply. Ensure that the power supply is turned off during installation;

[0032] Step 5: Turn on the power supply and gradually increase the current value of each power supply by turning the knob to gradually increase the temperature of the forming tube blank until the temperature of the forming tube blank 21 in the forming area reaches 750°C to 900°C and then keep it at this temperature for 1.5 minutes to 2.5 minutes;

[0033] Step 6: Start the hydraulic press, push the upper plate 1 downward, and expand the split die 9 through the mechanical structure. The pressure applied to the surface of the forming tube 21 causes the forming tube to undergo plastic deformation along the shape of the die 6 and the split die 9. The relative positions of the forming devices are as follows: Figure 3 As shown;

[0034] Step 7: When the upper push plate reaches the forming position, positive pressure argon gas is quickly filled into the cavity of the forming tube 21. The gas pressure is 3MPa~5MPa, and the temperature and pressure are maintained for 15min~25min.

[0035] Step 8: Gradually reduce the output current value of each power supply by turning the knob until the current value of each power supply reaches zero, then turn off the power supply, unload the argon gas pressure in the die to atmospheric pressure, and lift the upper push plate 1. The split die 9 is retracted inward under the action of the tightening spring;

[0036] Step nine: open the die 6, take out the formed tube blank 21, and use laser cutting to cut a group of formed tube blanks 21 into two independent formed parts.

Claims

1. A one-mold two-piece forming device for titanium alloy large-diameter and small-width seals, characterized by: The one-die two-piece forming device for a titanium alloy large-diameter and small-width seal comprises: a hydraulic press, an upper push plate (1), an upper push plate insulating layer (2), an upper electrode (4), an upper electrode auxiliary block (3), an upper sealing ring (5), a die (6), a die insulating layer (7), a split die positioning spring (8), a split die (9), a split die tightening spring (10), a split die insulating layer (11), a lower push plate (12), a lower push plate insulating layer (13), a lower electrode (15), a lower electrode auxiliary block (14), a lower sealing ring (16), a temperature measuring thermoelectric Couple (17), upper spring (18), lower spring (19), high-pressure gas inlet (20), power supply; wherein, the upper push plate (1) and the lower push plate (12) are respectively connected to the upper platform and the lower platform of the hydraulic press, the upper electrode (4) and the upper electrode auxiliary block (3) are respectively connected to the upper push plate (1), the lower electrode (15) and the lower electrode auxiliary block (14) are respectively connected to the lower push plate (12); an upper push plate insulating layer (2) is respectively provided between the upper push plate (1) and the upper electrode (4) and the upper electrode auxiliary block (3), and the lower push plate insulating layer (2) is provided between the upper push plate (1) and the upper electrode (4) and the upper electrode auxiliary block (3). A lower push plate insulating layer (13) is provided between the push plate (12) and the lower electrode (15) and the lower electrode auxiliary block (14), respectively. The upper sealing ring (5) and the lower sealing ring (16) are respectively placed in the grooves in the upper push plate (1) and the lower push plate (12), the split mold (9) is connected to the upper push plate (1) through the split mold positioning spring (8), the split mold (9) has a built-in split mold tightening spring (10), and the inner surface of the die (6) and the outer surface of the die (9) are respectively provided with a die insulating layer at the position in contact with the forming tube blank (21). The upper and lower ends of the die (6) are connected to the upper push plate (1) and the lower push plate (12) respectively through the upper spring (18) and the lower spring (19). The die (6) can be opened in half along the center line. The upper electrode (4) and the lower electrode (15) are multiple groups, and each group of electrodes is arranged correspondingly up and down. The upper electrode (4) and the lower electrode (15) are electrically connected to the power supply. The upper push plate (1) is provided with a high-pressure gas inlet (20) in the vertical direction, and the temperature measuring thermocouple (17) is located in the through hole of the die (6).

2. A forming method using the one-mold two-piece forming device for titanium alloy large-diameter and small-width seals according to claim 1, characterized in that: The specific steps of the one-mold two-piece forming method for titanium alloy large-diameter and small-width seals are as follows: Step 1: cutting the titanium alloy slab according to the size of the titanium alloy thin-walled sealing component, rolling the titanium alloy slab into a cylinder and welding it into a formed cylinder blank (21); Step 2: performing an insulating coating treatment between the upper push plate (1) and the upper electrode (4) and the upper electrode auxiliary block (3), performing an insulating coating treatment between the lower push plate (12) and the lower electrode (15) and the lower electrode auxiliary block (14), and performing an insulating coating treatment on the inner surface of the die (6) and the outer surface of the split die (9) at the portion in contact with the forming barrel (21), with the coating thickness being between 10 μm and 500 μm; Step 3: Install the upper push plate (1) and the lower push plate (12) on the upper platform and the lower platform of the hydraulic press respectively, and then install the split mold positioning spring (8), the split mold (9), the split mold tightening spring (10), the upper sealing ring (5), the lower sealing ring (16), the upper electrode auxiliary block (3) and the lower electrode auxiliary block (14), the forming cylinder (21), the upper spring (18), the concave mold (6), the lower spring (19), the upper electrode (4) and the lower electrode (15); Step 4: Connect each set of upper electrodes (4) and lower electrodes (15) to a corresponding power source; Step 5: Turn on the power supply and gradually increase the current density until the temperature of the formed tube blank (21) reaches 700°C to 950°C and then keep it warm for 1min to 3min; Step 6: Start the hydraulic press, move the upper push plate (1) downward, and open the split die (9) to plastically deform the formed cylinder (21) along the shape of the concave die (6) and the split die (9); Step 7: When the upper push plate reaches the forming position, positive pressure gas is filled in, the gas pressure is less than 10MPa, and the temperature and pressure are kept for 10min to 30min; Step 8: Gradually reduce the current value until it reaches zero, turn off the power, unload the air pressure, lift the upper push plate (1), and retract the petal mold (9); Step nine: Open the die (6), take out the formed tube blank (21), and cut the formed tube blank (21) into two independent formed parts.

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