An apparatus and method for sequential casting and ultrasonic treatment assisted blade preparation

Abstract

The application relates to a device and a method for sequentially casting and ultrasonic treatment assisted blade preparation, and relates to the field of turbine blade preparation. The application is used for solving the problems of low melt purity, low energy utilization rate, high shrinkage cavity and shrinkage porosity defect rate and coarse grain structure in the existing turbine blade production. The device comprises: an upper melting crucible used for melting metal raw materials; a middle flow control mechanism arranged at the bottom of the upper melting crucible and used for stably guiding high-temperature melt from the upper melting crucible into a lower cooling crucible; the lower cooling crucible is used for solidifying turbine blades; an induction heating coil is arranged around the upper melting crucible and the lower cooling crucible respectively; and an ultrasonic vibration device is arranged at the top and the bottom of the lower cooling crucible. The melting method comprises the following steps: in an inert gas atmosphere, metal raw materials are melted in the upper melting crucible, high-temperature metal melt is transferred into the lower cooling crucible through the middle flow control mechanism, and ultrasonic treatment is coupled, and the upper and lower crucibles are cooperatively designed in sequence. The application is used for turbine blade preparation.

Description

Technical Field

[0001] This invention relates to a turbine blade casting apparatus and method, specifically to a sequential casting and ultrasonic treatment-assisted blade preparation apparatus and method, belonging to the technical field of ultrasonic-assisted induction melting for turbine blade production. Background Technology

[0002] Gas turbines are important thermal power plants in the world today, laying the foundation for the continuous development of aviation power and are hailed as the "crown jewel" of industry. Turbine blades are the most critical hot-end components of gas turbines, operating for extended periods in harsh environments such as high temperatures (>1000℃), high pressure, complex stress fields, and high-temperature oxidation. Therefore, the performance level of turbine blades is an important indicator of the engine's advancement, and their manufacturing process is one of the most challenging technologies in the field of gas turbines.

[0003] Traditional turbine blade manufacturing typically employs a process that separates smelting and casting. During the transfer of high-temperature molten metal, it is prone to contact with air, which can easily lead to defects such as oxidation inclusions, resulting in low purity of the molten metal. At the same time, temperature loss occurs during the transfer of the molten metal, resulting in large temperature fluctuations and low energy utilization. The casting process relies on traditional gravity casting, which can easily cause defects such as air entrapment and cold shuts. Furthermore, it is also prone to forming defects such as shrinkage cavities and porosity in the later stages of solidification, resulting in a high scrap rate. In addition, the cooling rate caused by the single heat source direction is limited (1~5 mm / min), which promotes the growth of nucleated grains along the temperature gradient direction. The final solidified grain structure is uneven, and some grains are relatively coarse, which greatly reduces the high-temperature strength of the turbine blade.

[0004] Currently, ultrasonic treatment can promote both macroscopic and microscopic flow in melts. It allows for non-contact control of high-temperature melts, promoting uniform temperature distribution and timely replenishing porosity formed during solidification due to shrinkage. This effectively enhances the compensating ability of high-temperature molten metals, significantly improving defects such as shrinkage cavitation and porosity. Furthermore, the acoustic flow and cavitation effects induced by ultrasonic treatment can break primary dendrite arms, promoting the formation of fine equiaxed crystals. Therefore, ultrasonic treatment can overcome the material defects and microstructure control bottlenecks in traditional turbine blade manufacturing processes, providing an innovative path for further promoting high-performance, low-cost turbine blade manufacturing.

[0005] In summary, existing turbine blade manufacturing processes suffer from problems such as low melt purity, low energy utilization, high shrinkage and porosity defect rates, and coarse grain structure. Summary of the Invention

[0006] The purpose of this invention is to solve the problems of low melt purity, low energy utilization, high shrinkage porosity and defect rate, and coarse grain structure in existing turbine blade production. Therefore, it provides an apparatus and method for sequential casting and ultrasonic treatment-assisted blade preparation.

[0007] The technical solution of this invention is as follows: A device for sequential melting and ultrasonic treatment-assisted blade preparation includes an upper melting crucible, a middle flow control mechanism, a lower cold crucible, an induction coil, and a cooling water circuit. The upper melting crucible is a cylindrical crucible with an open top, and its interior is used to hold the metal raw material to be melted. The middle flow control mechanism is located at the bottom of the upper melting crucible and includes a high-temperature resistant valve body, a filter screen, and a flow guide groove. The high-temperature resistant valve body is an inverted conical valve body, and the flow guide groove is installed at the small end opening at the bottom of the high-temperature resistant valve body. The filter screen is installed at the large end opening on the upper part of the high-temperature resistant valve body and is integrated with the high-temperature resistant valve body. The lower cold crucible is a horizontal split structure and is installed directly below the middle flow control mechanism. The lower cold crucible is divided into a left crucible and a right crucible along the center line of the inner cavity curve of the turbine blade. A cold crucible cover is set on the lower cold crucible. The cooling water circuit includes a first water cooling channel and a second water cooling channel, which are located in the left crucible and the right crucible, respectively. The induction coil is wound on the upper melting crucible and the lower cold crucible, respectively.

[0008] Furthermore, the induction coil includes a first induction coil and a second induction coil. The first induction coil is spirally wound around the upper melting crucible, and the second induction coil is spirally wound around the lower cold crucible. The coil radii of the first and second induction coils are both 6-8 mm larger than the radii of the upper melting crucible and the lower cold crucible.

[0009] Preferably, the first induction coil has a total of 6 to 8 turns and a coil turn spacing of 10 to 15 mm; the second induction coil has a total of 4 to 6 turns and a coil turn spacing of 10 to 15 mm.

[0010] Furthermore, it also includes an ultrasonic vibration device, which comprises an upper ultrasonic vibration unit and a lower ultrasonic vibration unit. The upper and lower ultrasonic vibration units are arranged in a mirror image of each other, and a distance is left between the upper and lower ultrasonic vibration units.

[0011] Preferably, the upper ultrasonic vibration unit includes an upper ultrasonic probe, an upper ultrasonic generator rod, and an upper ultrasonic controller, which are installed sequentially from bottom to top; the lower ultrasonic vibration unit includes a lower ultrasonic probe, a lower ultrasonic generator rod, and a lower ultrasonic controller, which are installed sequentially from top to bottom.

[0012] Preferably, the upper melting crucible is made of graphite-based material and lined with tantalum coating; the high-temperature resistant valve body and filter screen of the middle flow control mechanism are made of silicon nitride.

[0013] Preferably, the lower cold crucible is a water-cooled copper crucible substrate, and a tantalum-coated liner is provided on the inner wall of the water-cooled copper crucible substrate.

[0014] Furthermore, it also includes a rotating mechanism, a closed cavity, a support frame, a power supply, an air extraction device, and an air supply source. The support frame is installed in the middle of the closed cavity, the rotating mechanism is installed on the support frame, the power supply is connected to the inside of the closed cavity, and the air extraction device and the air supply source are both connected to the inside of the closed cavity.

[0015] The rotating mechanism includes a rod, a turntable, and a drive assembly. The drive assembly is built into a support frame. The turntable is rotatably mounted on the support frame, and the drive assembly drives the turntable to rotate circumferentially. The lower cold crucible is mounted on the turntable. The rod is vertically mounted at the center of the turntable and does not rotate with the turntable. The upper melting crucible and the upper ultrasonic vibration unit are fixedly mounted on the upper part of the rod, and the lower ultrasonic vibration unit is mounted on the support frame.

[0016] The present invention also provides a method for casting turbine blades, which includes the following steps:

[0017] Step 1: Preparation of turbine blade materials:

[0018] Step 11: Based on the design composition of the alloy turbine blade and the alloy burn-off rate, calculate the required types and proportions of raw materials, control the purity of the alloy raw materials to be >99.9%, and strictly weigh the required raw materials according to the turbine blade volume;

[0019] Steps 1 and 2: Place the raw materials in the upper melting crucible, close the sealed cavity, evacuate and introduce inert gas, and repeat the above operation 1 to 2 times;

[0020] Step Two: Melting the Alloy;

[0021] The first induction coil at the upper melting crucible is activated at a frequency of 100~150kHz and a power of 50~100kW to heat the raw material in the upper melting crucible to above the alloy melting point and maintain it for 5~10 minutes. Then the first induction coil at the upper melting crucible is turned off to proceed with the subsequent casting process.

[0022] Step 3: Casting the alloy;

[0023] Step 31: Turn on the second induction coil 1-3 minutes in advance, open the first and second water cooling channels in the lower cold crucible, and adjust the frequency of the second induction coil to 20kHz and the power to 20-30kW.

[0024] Step 32: Under the action of the rotating mechanism, rotate the lower cold crucible to below the upper melting crucible, rotate to open the lower cold crucible cover, check whether the guide groove of the middle flow control mechanism is aligned with the lower cold crucible, turn on the middle flow control mechanism switch, and the molten metal is injected into the lower cold crucible after being filtered by the filter screen.

[0025] Step 4: Ultrasonic vibration and cooling of the alloy;

[0026] Step 41: After pouring, rotate and close the lower cold crucible cover. Under the action of the rotating mechanism, rotate the lower cold crucible to the position below the upper ultrasonic probe. Adjust the frequency of the second induction coil to 30~50kHz and the power to 30~50kW. After holding for 5 minutes, turn off the second induction coil.

[0027] Step 42: Turn on the upper and lower ultrasonic vibration units of the lower cold crucible to perform ultrasonic treatment on the melt in the lower cold crucible. At the same time, pass cooling water at 15~30℃ through the first and second water cooling channels. After 4~8 minutes, turn off the upper and lower ultrasonic vibration units of the lower cold crucible. After 10~15 minutes, turn off the first and second water cooling channels of the lower cold crucible, open the sealed cavity, take out the turbine blade and check whether the surface quality of the blade is intact. At this point, the preparation of the turbine blade is completed.

[0028] Furthermore, the evacuation and inert gas introduction in step one specifically involve: opening the evacuation device to create a vacuum of 1×10⁻⁶. - 3 Pa, turn off the pumping device, turn on the gas supply source to introduce high-purity argon gas to -0.5MPa, then turn off the gas supply source. Repeat the above operation 1 to 2 times.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] This invention achieves integrated melting-casting-solidification processes through a sequential upper and lower crucible collaborative design. This reduces temperature loss and secondary oxidation during the original molten metal transfer process, improves the purity of the molten metal and production efficiency, and shortens the production cycle. The reduced temperature loss during molten metal transfer solves the problems of low melt purity and low energy utilization in turbine blade production. Furthermore, the mechanical stirring effect of ultrasonic treatment intensifies the macroscopic flow of the molten metal, effectively improving macroscopic defects such as shrinkage cavities and porosity. Simultaneously, the cavitation and acoustic flow effects of ultrasonic treatment break primary dendrite arms, promoting the formation of fine equiaxed crystals. Ultimately, this results in turbine blades with fine microstructure and good performance, solving the problems of high shrinkage cavities and porosity and coarse grain structure in turbine blade production, and improving the yield of turbine blades. Attached Figure Description

[0031] Figure 1This is a schematic diagram of the device for preparing blades by sequential melting and ultrasonic treatment according to the present invention.

[0032] Figure 2 This is a partial enlarged cross-sectional view of the flow control mechanism in the device of the present invention.

[0033] Figure 3 This is a schematic diagram of the lower cold crucible and internal cooling water circuit of the device of the present invention.

[0034] Figure 4 This is a three-dimensional schematic diagram of the turbine blade prepared by the device of the present invention.

[0035] In the diagram: 1. Upper melting crucible; 2. Middle flow control mechanism; 21. High-temperature resistant valve body; 22. Filter screen; 23. Flow guide groove; 3. Lower cold crucible; 4. Induction coil; 41. First induction coil; 42. Second induction coil; 5. Cooling water channel; 51. First water-cooling channel; 52. Second water-cooling channel; 6. Ultrasonic vibration device; 61. Upper ultrasonic probe; 62. Lower ultrasonic probe; 63. Upper ultrasonic generator rod; 64. Lower ultrasonic generator rod; 65. Upper ultrasonic controller; 66. Lower ultrasonic controller; 7. Rotation mechanism; 71. Rod body; 72. Turntable; 8. Support frame; 9. Enclosed cavity; 10. Power supply; 11. Air extraction device; 12. Air supply source. Detailed Implementation

[0036] Specific implementation method one: Combining Figures 1 to 4 This embodiment describes a sequential melting and ultrasonic treatment-assisted blade preparation device, comprising an upper melting crucible 1, a middle flow control mechanism 2, a lower cooling crucible 3, an induction coil 4, and a cooling water circuit 5. The upper melting crucible 1 is a cylindrical crucible with an open top, and its interior is used to hold the metal raw material to be melted. The middle flow control mechanism 2 is located at the bottom of the upper melting crucible 1 and includes a high-temperature resistant valve body 21, a filter screen 22, and a flow guide groove 23. The high-temperature resistant valve body 21 is an inverted conical valve body, and the flow guide groove 23 is installed at the small end opening at the lower part of the high-temperature resistant valve body 21 and is connected to the high-temperature resistant valve body 21. The high-temperature valve body 21 is made as one piece, and the filter screen 22 is installed at the large end opening on the upper part of the high-temperature valve body 21; the lower cold crucible 3 is a horizontal split structure, and the lower cold crucible 3 is installed directly below the middle flow control mechanism 2. The lower cold crucible 3 is divided into a left crucible 31 and a right crucible 32 along the center line of the inner cavity curve of the turbine blade. A cold crucible cover 33 is set on the lower cold crucible 3. The cooling water channel 5 includes a first water cooling channel 51 and a second water cooling channel 52, which are located in the left crucible 31 and the right crucible 32, respectively; the induction coil 4 is wound on the upper melting crucible 1 and the lower cold crucible 3, respectively.

[0037] In this embodiment, the middle layer flow control mechanism 2 is equipped with a high-temperature resistant valve body 21, a filter screen 22, and a flow guide groove 23 to ensure that the alloy in the upper melting crucible 1 can be smoothly poured into the lower cold crucible 3, thereby reducing air entrapment.

[0038] In this embodiment, the volume design of the cylindrical crucible (error ≤ ±3%) is matched with the volume of a single blade to reduce molten metal residue and improve energy utilization.

[0039] In this embodiment, the lower cold crucible 3 has cooling water channels 5 inside the left crucible 31 and right crucible 32, respectively, to provide a suitable temperature gradient for the high-temperature melt. The first water cooling channel 51 consists of left channel 5101, left channel 5102, left channel 5103 and left channel 5104, and the second water cooling channel 52 consists of right channel 5201, right channel 5202, right channel 5203 and right channel 5204.

[0040] Specific Implementation Method Two: Combining Figure 1 In this embodiment, the induction coil 4 includes a first induction coil 41 and a second induction coil 42. The first induction coil 41 is spirally wound around the upper melting crucible 1, and the second induction coil 42 is spirally wound around the lower cold crucible 3. The coil radii of the first induction coil 41 and the second induction coil 42 are both 6-8 mm larger than the radii of the upper melting crucible 1 and the lower cold crucible 3.

[0041] This configuration avoids direct contact and ensures sufficient electromagnetic field coverage. Other components and connections are the same as in Specific Implementation Method 1.

[0042] Specific implementation method three: Combining Figure 1 In this embodiment, the first induction coil 41 has 6-8 turns in total, with a coil turn spacing of 10-15 mm; the second induction coil 42 has 4-6 turns in total, with a coil turn spacing of 10-15 mm. This arrangement avoids the problems of overheating due to magnetic field superposition caused by too small a coil turn spacing and low energy utilization caused by too large a coil turn spacing. Other components and connections are the same as in specific embodiments one or two.

[0043] Specific implementation method four: Combination Figure 1This embodiment further includes an ultrasonic vibration device 6, which comprises an upper ultrasonic vibration unit and a lower ultrasonic vibration unit. The upper and lower ultrasonic vibration units are arranged in a mirror image, with a distance between them. This distance is greater than the height of the lower cold crucible 3, ensuring that the lower cold crucible 3, driven by the rotating mechanism 7, is positioned between the upper and lower ultrasonic vibration units. Non-contact ultrasonic vibration devices 6 are installed at the top and bottom of the lower cold crucible to avoid contaminating the high-temperature melt, while simultaneously allowing for sufficient ultrasonic treatment of the turbine blades to obtain an equiaxed fine microstructure. Other components and connections are the same as in specific embodiments one, two, or three.

[0044] Specific Implementation Method Five: Combining Figure 1 This embodiment describes an upper ultrasonic vibration unit comprising an upper ultrasonic probe 61, an upper ultrasonic generator rod 63, and an upper ultrasonic controller 65, which are installed sequentially from bottom to top. The lower ultrasonic vibration unit comprises a lower ultrasonic probe 62, a lower ultrasonic generator rod 64, and a lower ultrasonic controller 66, which are installed sequentially from top to bottom. This configuration is simple and facilitates operation on both the upper and lower parts of the lower cold crucible 3. Other components and connections are the same as in specific embodiments one, two, three, or four.

[0045] Specific Implementation Method Six: Combination Figure 1 In this embodiment, the upper melting crucible 1 is made of graphite-based material and lined with tantalum coating; the high-temperature resistant valve body 21 and filter screen 22 of the middle flow control mechanism 2 are made of silicon nitride.

[0046] With this configuration, the material of the upper melting crucible 1 can ensure sufficient structural strength and high temperature resistance, while the graphite-based material has good thermal conductivity and high efficiency; the inner lining is coated with tantalum (Ta) to isolate the high-temperature molten metal from reacting with the graphite-based material.

[0047] A filter screen is placed in the middle layer flow control mechanism to filter impurities and slag during the smelting process. The filter screen is made of silicon nitride (Si3N4) material to withstand the higher temperatures of the molten metal. Other components and connections are the same as in specific embodiments one, two, three, four, or five.

[0048] The high-temperature resistant valve body of this embodiment uses silicon nitride (Si3N4) composite material, which has strong heat resistance and does not react with high-temperature melt. The flow control valve port is a conical valve port with an adjustable valve port diameter (1~10mm) to control the casting flow rate.

[0049] Specific implementation method seven: Combination Figure 1 In this embodiment, the lower cold crucible 3 is a water-cooled copper crucible substrate, and a tantalum-coated liner is provided on the inner wall of the water-cooled copper crucible substrate.

[0050] In this configuration, the lower cold crucible uses a water-cooled copper crucible base with a tantalum (Ta) coated liner to rapidly transfer heat and prevent reaction with the high-temperature melt. Other components and connections are the same as in specific embodiments one, two, three, four, five, or six.

[0051] Specific implementation method eight: Combination Figure 1 This embodiment also includes a rotating mechanism 7, a closed cavity 9, a support frame 8, a power supply 10, an air extraction device 11, and an air supply source 12. The support frame 8 is installed in the middle of the closed cavity 9, the rotating mechanism 7 is installed on the support frame 8, the power supply 10 is connected to the inside of the closed cavity 9, and the air extraction device 11 and the air supply source 12 are both connected to the inside of the closed cavity 9.

[0052] The rotating mechanism 7 includes a rod 71, a turntable 72, and a drive assembly. The drive assembly is built into the support frame 8. The turntable 72 is rotatably mounted on the support frame 8, and the drive assembly drives the turntable 72 to rotate circumferentially. The lower cold crucible 3 is mounted on the turntable 72. The rod 71 is vertically mounted at the center of the turntable 72 and does not rotate with the turntable 72. The upper melting crucible 1 and the upper ultrasonic vibration unit are fixedly mounted on the upper part of the rod 71, and the lower ultrasonic vibration unit is mounted on the support frame 8.

[0053] This design of the enclosed cavity 9 in this embodiment is intended to prevent secondary oxidation of the high-temperature melt during smelting and casting. Other components and connections are the same as in any of the specific embodiments one through seven.

[0054] Specific Implementation Method Nine: Combining Figures 1 to 4 This embodiment describes a blade preparation method that includes the following steps:

[0055] Step 1: Preparation of turbine blade materials:

[0056] Step 11: Based on the design composition of the alloy turbine blade and the alloy burn-off rate, calculate the required types and proportions of raw materials, control the purity of the alloy raw materials to be >99.9%, and weigh the required raw materials strictly according to the turbine blade volume; in order to avoid the generation of waste gas and other impurities during the smelting process affecting the subsequent casting process, the purity of the raw materials used is greater than 99.9%.

[0057] Steps 1 and 2: Place the raw material in the upper melting crucible 1, close the sealed cavity 9, evacuate the air and introduce inert gas, and repeat the above operation 1 to 2 times;

[0058] Step Two: Melting the Alloy;

[0059] The first induction coil 41 at the upper melting crucible 1 is activated at a frequency of 100~150kHz and a power of 50~100kW to heat the raw material in the upper melting crucible 1 to above the alloy melting point and maintain it for 5~10 minutes. Then the first induction coil 41 at the upper melting crucible 1 is turned off to proceed with the subsequent casting process.

[0060] Step 3: Casting the alloy;

[0061] Step 31: Turn on the second induction coil 42 1-3 minutes in advance, open the first water cooling channel 51 and the second water cooling channel 52 in the lower cold crucible 3, and adjust the frequency of the second induction coil 42 to 20kHz and the power to 20-30kW.

[0062] Step 32: Under the action of the rotating mechanism 7, rotate the lower cold crucible 3 to below the upper melting crucible 1, rotate and open the lower cold crucible cover 33, check whether the guide groove 23 of the middle flow control mechanism 2 is aligned with the lower cold crucible 3, turn on the switch of the middle flow control mechanism 2, and the molten metal is injected into the lower cold crucible 3 after being filtered by the filter screen 22.

[0063] Step 4: Ultrasonic vibration and cooling of the alloy;

[0064] Step 41: After pouring, rotate and close the lower cold crucible cover 33. Under the action of the rotating mechanism 7, rotate the lower cold crucible 3 down to the upper ultrasonic probe 61. Adjust the frequency of the second induction coil 42 to 30~50kHz and the power to 30~50kW. After keeping it warm for 5 minutes, close the second induction coil 42.

[0065] Step 42: Activate the upper and lower ultrasonic vibration units of the lower cold crucible 3 to perform ultrasonic treatment on the melt in the lower cold crucible 3. Simultaneously, circulate cooling water at 15-30°C through the first and second water-cooling channels 51 and 52. After 4-8 minutes, close the upper and lower ultrasonic vibration units of the lower cold crucible 3. After 10-15 minutes, close the first and second water-cooling channels 51 and 52 of the lower cold crucible 3. Open the sealed cavity 9, remove the turbine blade, and check whether the blade surface quality is intact. This completes the preparation of the turbine blade. Other components and connections are the same as in any one of the specific embodiments one to eight.

[0066] Specific Implementation Method Ten: Combining Figures 1 to 4 This embodiment describes the following steps in which the air is evacuated and inert gas is introduced: The air evacuation device 11 is turned on to evacuate to a vacuum level of 1×10⁻⁶. -3 Pa, close the pumping device 11, open the gas supply source 12 to introduce high-purity argon gas to -0.5MPa, then close the gas supply source 12. Repeat the above operation 1~2 times.

[0067] Combination Figures 1 to 4 Explanation of the working principle of this invention:

[0068] See the appendix of this invention. Figures 1 to 4 According to an embodiment of the present invention, an apparatus for sequential casting and ultrasonic treatment-assisted blade preparation includes:

[0069] The upper melting crucible 1 has a cylindrical inner cavity design with an open top. The inner diameter R1 and the height H1 of the upper melting crucible are designed according to the volume of a single blade (error ≤ ±3%).

[0070] The middle layer flow control mechanism 2 is located at the bottom of the upper melting crucible 1 and includes a high-temperature resistant valve body 21, a filter screen 22 and a flow guide groove 23.

[0071] The lower cold crucible 3 is a horizontally split structure, divided into a left crucible 31 and a right crucible 32 along the center line of the inner cavity curve of the turbine blade. A cold crucible cover 33 is provided on the lower cold crucible 3 to prevent the high-temperature melt from spilling during rotation. The left and right crucibles are respectively provided with a first water cooling channel 51 and a second water cooling channel 52 inside the left and right crucibles.

[0072] The induction coil 4 includes a first induction coil 41 and a second induction coil 42. The first induction coil 41 is spirally wound around the upper melting crucible 1. The radius of the first induction coil R41 is 5-10 mm larger than the outer diameter R1' of the upper melting crucible 1. Similarly, the second induction coil is spirally wound around the lower cold crucible 3. The radius of the second induction coil R42 is 6 mm larger than the radius R3 of the lower melting crucible.

[0073] The ultrasonic vibration device 6 is divided into an upper ultrasonic probe 61, a lower ultrasonic probe 62, an upper ultrasonic generator rod 63, a lower ultrasonic generator rod 64, an upper ultrasonic controller 65, and a lower ultrasonic controller 66.

[0074] The rotating mechanism 7 is located below the lower cold crucible 3 and can move the lower cold crucible 3 between the upper ultrasonic probe 61 and the upper melting crucible 1.

[0075] This invention also discloses a blade manufacturing method, which uses the aforementioned sequential casting and ultrasonic treatment-assisted blade manufacturing apparatus, taking the manufacture of niobium-silicon based alloy turbine blades (composition Nb-16Si-20Ti-2Zr-1C-2B) as an example:

[0076] Step 1: First, based on the design composition of the niobium-silicon based alloy turbine blade (Nb-16Si-20Ti-2Zr-1C-2B) and the alloy burn-off rate, calculate the required raw material types and proportions. The raw materials are 60 at% Nb, 16 at% Si, 20 at% Ti, 2 at% Zr, 1 at% C, and 1 at% B. The purity of the alloy raw materials is >99.9%, and the turbine blade volume is strictly controlled according to the design. 3 The inner diameter R1 of the upper melting crucible is determined to be 18cm, and the height H1 of the upper melting crucible is determined to be 30cm. The required raw materials are weighed and placed in the upper melting crucible 1. The sealed cavity 9 is closed, and the vacuum device 11 is turned on to evacuate to a vacuum level of 1×10⁻⁶. -3 Pa, close the pumping device 11, open the gas supply source 12 to introduce high-purity argon gas to -0.5MPa, then close the gas supply source 12. Repeat the above operation 1~2 times.

[0077] Step 2: Activate the first induction coil 41 at the upper melting crucible 1 with a frequency of 150kHz and a power of 100kW to heat the raw material in the upper melting crucible 1 to above 1800℃ and maintain it for 8 minutes. Then, turn off the first induction coil 41 at the upper melting crucible 1 and proceed with the subsequent casting process.

[0078] Step 3: Turn on the second induction coil 42 2 minutes in advance, turn on the cooling water channels 51 and 52 of the lower cold crucible 3, and adjust the frequency to 20kHz and the power to 30kW. Under the action of the rotating mechanism 7, rotate the lower cold crucible 3 to below the upper melting crucible 1, rotate and open the lower cold crucible cover 33, check whether the guide groove 25 of the middle flow control mechanism 2 is aligned with the lower cold crucible 3, turn on the switch of the middle flow control mechanism 2, and the molten metal is injected into the lower cold crucible 3 after being filtered by the filter screen 22.

[0079] Step 4: After pouring, rotate and close the lower cold crucible cover 33. Under the action of the rotating mechanism 7, rotate the lower cold crucible 3 to the position below the upper ultrasonic probe 61. Adjust the frequency of the second induction coil 42 to 30kHz and the power to 30kW. After holding for 5 minutes, close the second induction coil 42 and turn on the upper and lower ultrasonic vibration units of the lower cold crucible 3 to perform ultrasonic treatment on the melt in the lower cold crucible. At the same time, 15~30℃ cooling water is circulated in the first water cooling channel 51 and the second water cooling channel 52. After 5 minutes, close the upper ultrasonic controller 65 at the top and the lower ultrasonic controller 66 at the bottom of the lower cold crucible 3. After 10 minutes, close the first water cooling channel 51 and the second water cooling channel 52 of the lower cold crucible 3, open the closed cavity 9, take out the turbine blades and check whether the surface quality of the blades is intact.

[0080] This invention achieves integrated melting-casting-solidification process through sequential upper and lower crucible collaborative design, and with the assistance of ultrasonic treatment, it can shorten the production cycle, reduce costs, and improve the purity and production efficiency of the molten metal; at the same time, it promotes the formation of fine equiaxed crystals, which can produce turbine blades with fine structure and good performance, thereby improving the yield of turbine blades.

[0081] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make other changes within the spirit of the invention and apply it to fields not mentioned in the invention. Of course, all such changes made in accordance with the spirit of the invention should be included within the scope of protection claimed by the invention.

Claims

1. A device for sequential melting and casting and ultrasonic treatment-assisted blade preparation, characterized in that: It includes an upper melting crucible (1), a middle flow control mechanism (2), a lower cold crucible (3), an induction coil (4), a cooling water channel (5), an ultrasonic vibration device (6), a rotating mechanism (7), a closed cavity (9), a support frame (8), a power supply (10), an air extraction device (11), and an air supply source (12). The upper melting crucible (1) is a cylindrical crucible with an open top. The interior of the upper melting crucible (1) is used to hold the metal raw materials to be melted. The middle flow control mechanism (2) is set at the bottom of the upper melting crucible (1). The middle flow control mechanism (2) includes a high-temperature resistant valve body (21), a filter screen (22), and a flow guide groove (23). The high-temperature resistant valve body (21) is an inverted conical valve body. The flow guide groove (23) is installed at the small end opening at the bottom of the high-temperature resistant valve body (21) and is integrated with the high-temperature resistant valve body (21). The filter screen (22) is installed at the large end opening at the top of the high-temperature resistant valve body (21). The lower cold crucible (3) It is a horizontal split structure. The lower cold crucible (3) is installed directly below the middle flow control mechanism (2). The lower cold crucible (3) is divided into a left crucible (31) and a right crucible (32) along the center line of the inner cavity curve of the turbine blade. A cold crucible cover (33) is set on the lower cold crucible (3). The cooling water channel (5) includes a first water cooling channel (51) and a second water cooling channel (52). The first water cooling channel (51) and the second water cooling channel (52) are located in the left crucible (31) and the right crucible (32) respectively. The induction coil (4) is wound on the upper melting crucible (1) and the lower cold crucible (3) respectively. The ultrasonic vibration device (6) includes an upper ultrasonic vibration unit and a lower ultrasonic vibration unit, which are arranged in a mirror image. A support frame (8) is installed in the middle of the closed cavity (9), and a rotating mechanism (7) is installed on the support frame (8). A power supply (10) is connected to the inside of the closed cavity (9), and both the air extraction device (11) and the air supply source (12) are connected to the inside of the closed cavity (9). The rotating mechanism (7) includes a rod (71), a turntable (72), and a drive assembly. The drive assembly is built into the support frame (8), and the turntable (72) is rotatably installed on the support frame (8). The drive assembly carries... The rotating turntable (72) rotates in a circle. The lower cold crucible (3) is installed on the turntable (72). The rod (71) is installed vertically at the center of the turntable (72) and does not rotate with the turntable (72). The upper melting crucible (1) and the upper ultrasonic vibration unit are fixedly installed on the upper part of the rod (71). The lower ultrasonic vibration unit is installed on the support frame (8). There is a distance between the upper ultrasonic vibration unit and the lower ultrasonic vibration unit. The distance is greater than the height of the lower cold crucible (3) to ensure that the lower cold crucible (3) is located between the upper ultrasonic vibration unit and the lower ultrasonic vibration unit under the drive of the rotating mechanism (7).

2. The apparatus for sequential casting and ultrasonic treatment-assisted blade preparation according to claim 1, characterized in that: The induction coil (4) includes a first induction coil (41) and a second induction coil (42). The first induction coil (41) is spirally wrapped around the upper melting crucible (1), and the second induction coil (42) is spirally wrapped around the lower cold crucible (3). The coil radii of the first induction coil (41) and the second induction coil (42) are both 6-8 mm larger than the radii of the upper melting crucible (1) and the lower cold crucible (3).

3. The apparatus for sequential casting and ultrasonic treatment-assisted blade preparation according to claim 2, characterized in that: The first induction coil (41) has a total of 6 to 8 turns and a coil turn spacing of 10 to 15 mm; the second induction coil (42) has a total of 4 to 6 turns and a coil turn spacing of 10 to 15 mm.

4. The apparatus for sequential casting and ultrasonic treatment-assisted blade preparation according to claim 3, characterized in that: The upper ultrasonic vibration unit includes an upper ultrasonic probe (61), an upper ultrasonic generator rod (63), and an upper ultrasonic controller (65), which are installed sequentially from bottom to top. The lower ultrasonic vibration unit includes a lower ultrasonic probe (62), a lower ultrasonic generator rod (64), and a lower ultrasonic controller (66), which are installed sequentially from top to bottom.

5. The apparatus for sequential casting and ultrasonic treatment-assisted blade preparation according to claim 1 or 4, characterized in that: The upper melting crucible (1) is made of graphite and lined with tantalum coating; the high-temperature valve body (21) and filter screen (22) of the middle flow control mechanism (2) are made of silicon nitride.

6. The apparatus for sequential casting and ultrasonic treatment-assisted blade preparation according to claim 5, characterized in that: The lower cold crucible (3) is a water-cooled copper crucible base, and a tantalum-coated liner is provided on the inner wall of the water-cooled copper crucible base.

7. A method for preparing blades using the apparatus for sequential casting and ultrasonic treatment assisted blade preparation as described in claim 6, characterized in that: It includes the following steps: Step 1: Preparation of turbine blade materials: Step 11: Based on the design composition of the alloy turbine blade and the alloy burn-off rate, calculate the required types and proportions of raw materials, control the purity of the alloy raw materials to be >99.9%, and strictly weigh the required raw materials according to the turbine blade volume; Step 1 and 2: Place the raw material in the upper melting crucible (1), close the sealed cavity (9), evacuate the air and introduce inert gas, and repeat the above operation 1 to 2 times; Step Two: Melting the Alloy; Start the first induction coil (41) at the upper melting crucible (1) with a frequency of 100~150kHz and a power of 50~100kW to heat the raw material in the upper melting crucible (1) to above the alloy melting point and maintain it for 5~10 minutes. Then turn off the first induction coil (41) at the upper melting crucible (1) and proceed with the subsequent casting process. Step 3: Casting the alloy; Step 31: Turn on the second induction coil (42) 1~3 minutes in advance, open the first water cooling channel (51) and the second water cooling channel (52) in the lower cold crucible (3), and adjust the frequency of the second induction coil (42) to 20kHz and the power to 20~30kW; Step 32: Under the action of the rotating mechanism (7), rotate the lower cold crucible (3) to below the upper melting crucible (1), rotate to open the lower cold crucible cover (33), check whether the guide groove (23) of the middle flow control mechanism (2) is aligned with the lower cold crucible (3), turn on the middle flow control mechanism (2), and the molten metal is injected into the lower cold crucible (3) after being filtered by the filter screen (22); Step 4: Ultrasonic vibration and cooling of the alloy; Step 41: After the pouring is completed, rotate and close the lower cold crucible cover (33). Under the action of the rotating mechanism (7), rotate the lower cold crucible (3) to the upper ultrasonic probe (61). Adjust the frequency of the second induction coil (42) to 30~50kHz and the power to 30~50kW. After keeping it warm for 5 minutes, close the second induction coil (42). Step 42: Turn on the upper and lower ultrasonic vibration units of the lower cold crucible (3) to perform ultrasonic treatment on the melt in the lower cold crucible (3). At the same time, pass cooling water at 15~30℃ through the first water cooling channel (51) and the second water cooling channel (52). After 4~8 minutes, turn off the upper and lower ultrasonic vibration units of the lower cold crucible (3). After 10~15 minutes, turn off the first water cooling channel (51) and the second water cooling channel (52) of the lower cold crucible (3). Open the closed cavity (9), take out the turbine blade and check whether the surface quality of the blade is intact. Thus, the preparation of the turbine blade is completed.

8. The blade preparation method according to claim 7, characterized in that: The specific steps for evacuation and inert gas introduction in step one are as follows: Open the evacuation device (11) and evacuate to a vacuum of 1×10⁻⁶. -3 Pa, close the pumping device (11), open the gas supply source (12) to introduce high-purity argon gas to -0.5MPa, then close the gas supply source (12). Repeat the above operation 1~2 times.

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