Ultrasonic preparation system and method for ultrafine metal powder

Abstract

The present invention belongs to the technical field of metal powder material preparation, and in particular relates to a system and method for ultrasonic preparation of ultrafine metal powder, including: an ultrasonic preparation method for ultrafine metal powder, including the following steps: step one, preparation of molten alloy liquid; step two, applying supersonic gas at the atomizing nozzle to atomize the molten alloy liquid into fine droplets; step three, simultaneously with step two, applying a high-frequency vibration field at the atomizing nozzle; step four, simultaneously with step three, applying ultrasonic waves to the powder making center area, and an ultrafine metal powder ultrasonic preparation system, including a vacuum chamber; a vacuum system; a smelting system; an ultrasonic atomizing powder making system; and a powder collecting system. The present invention adopts a combination of high-frequency vibration and high-pressure gas atomization to apply high-frequency vibration to the high-pressure gas atomization spray disc system, so that the metal powder has a suitable cooling and solidification environment during the gas atomization process, thereby improving the metal fine powder recovery rate, enhancing the powder sphericity, and reducing the generation of satellite powder.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal powder material preparation, and in particular relates to a system and method for ultrasonically preparing ultrafine metal powder. Background Art

[0002] Gas atomization powder production is a powder production process in which supersonic gas is applied to the atomizing nozzle to impact and crush the molten alloy liquid, atomizing it into fine droplets on the micron scale. The droplets are then spheroidized and solidified into powder. The VIGA method is mainly suitable for the production and preparation of powders such as iron-based alloys, nickel-based alloys, cobalt-based alloys, aluminum-based alloys, and copper-based alloys. The EIGA method can achieve safe and clean smelting of active metals and is mainly used in the preparation of powder materials such as active metals and their alloys, intermetallic compounds, and refractory metals, such as titanium and titanium alloys, and titanium-aluminum intermetallic compounds. However, the powder produced by gas atomization powder production has slightly poor sphericity, a high content of satellite powders, and a high hollow powder rate in the 15-53μm range. It is not suitable for direct use in powder metallurgy fields such as electron beam selective melting and direct hot isostatic pressing.

[0003] In order to solve the problems of poor powder sphericity, excessive satellite powder, and high hollow powder rate of 15-53μm powder, we proposed an ultrafine metal powder ultrasonic preparation system and method to solve them. Summary of the Invention

[0004] The purpose of the present invention is to provide a system and method for ultrasonically preparing ultrafine metal powder to solve the above problems.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A method for ultrasonically preparing ultrafine metal powder comprises the following steps:

[0007] Step 1: preparing the molten alloy liquid;

[0008] Step 2: Apply supersonic gas at the atomizing nozzle to atomize the molten alloy liquid into fine droplets;

[0009] Step 3: Simultaneously with step 2, a high-frequency vibration field is applied to the atomizing nozzle;

[0010] Step 4: Simultaneously with step 3, apply ultrasonic waves to the center area of the milling process.

[0011] An ultrafine metal powder ultrasonic preparation system, based on the above-mentioned ultrafine metal powder ultrasonic preparation method, comprises:

[0012] Vacuum chamber;

[0013] A vacuum system connected to one side of the vacuum chamber and used to maintain a vacuum environment in the vacuum chamber;

[0014] A smelting system, disposed in the vacuum chamber, for preparing a molten alloy liquid;

[0015] An ultrasonic atomization powder making system is arranged in the vacuum chamber, wherein a discharge end of the ultrasonic atomization powder making system is connected to a discharge end of the smelting system and is used to divide the molten alloy liquid into metal powder balls;

[0016] The powder collecting system is connected to the discharge end of the vacuum chamber and is used to collect the prepared metal powder balls.

[0017] Preferably, the vacuum chamber comprises a smelting chamber, an atomizing chamber and an atomizing cone section which are sequentially connected from top to bottom, the top of the smelting chamber is movably connected to a smelting chamber furnace cover, and there are at least one atomizing chamber and at least one atomizing cone section;

[0018] The vacuum system is connected to one side of the smelting chamber or the atomization chamber;

[0019] The smelting system is located in the smelting chamber;

[0020] The ultrasonic atomization powder making system is located in the smelting chamber, and the discharge end of the ultrasonic atomization powder making system is arranged in the atomization chamber;

[0021] The discharge end of the atomizing cone section is communicated with the feed end of the powder collecting system.

[0022] Preferably, the smelting system comprises a main smelter and a tundish arranged in the smelting chamber;

[0023] The main smelter is electrically connected to a main smelting power supply;

[0024] The tundish is electrically connected to a tundish power supply;

[0025] The main smelter is fixedly connected to the output shaft of a tilting hydraulic cylinder, and the fixed end of the tilting hydraulic cylinder is hinged on the side wall of the smelting chamber; the tilting hydraulic cylinder is used to tilt the main smelter;

[0026] The tundish is fixedly connected to the smelting chamber;

[0027] After the main smelter is turned over, the discharge end of the main smelter is located directly above the feed end of the tundish;

[0028] The discharge end of the tundish is communicated with the feed end of the ultrasonic atomization powder making system.

[0029] Preferably, the tundish includes a support plate, the support plate is fixed to the bottom of the smelting chamber via a plurality of support columns, a cap is fixed to the top of the support plate, a tundish crucible is fixed to the bottom of the support plate, and the tundish crucible is communicated with the cap;

[0030] The outside of the tundish crucible is wrapped with a graphite heating ring, the outside of the graphite heating ring is wrapped with a thermal insulation layer, the outside of the thermal insulation layer is wrapped with an induction coil, and a plurality of tundish temperature-controlling thermocouples for controlling the temperature in the tundish crucible are inserted into the graphite heating ring, and the tundish temperature-controlling thermocouples are electrically connected to the tundish power supply;

[0031] The bottom of the tundish crucible is communicated with the feed end of the ultrasonic atomization powder making system.

[0032] Preferably, the ultrasonic atomization powder making system comprises a guide nozzle, the feed end of the guide nozzle is connected to the bottom of the tundish crucible, and the discharge end of the guide nozzle is connected to the middle of the atomizing spray disc;

[0033] An ultrasonic airflow jet portion is provided in the atomizing spray disc, and the nozzle of the ultrasonic airflow jet portion is arranged toward the discharge end of the guide nozzle;

[0034] The bottom of the atomizing spray disc is provided with an ultrasonic vibration part;

[0035] A plurality of ultrasonic radiation rods are provided below the atomizing spray disc, and the plurality of ultrasonic radiation rods are fixedly connected to the inner wall of the atomizing chamber at the top at equal intervals in the circumferential direction, and the emitting ends of the ultrasonic radiation rods are arranged toward the discharge end of the guide nozzle.

[0036] Preferably, the atomizing spray disc includes an upper plate and a lower plate, and the ultrasonic airflow jet portion is located between the upper plate and the lower plate.

[0037] The ultrasonic air flow injection portion includes a spray disc high-pressure air cavity, which is located between the spray disc upper plate and the spray disc lower plate. A plurality of high-pressure jet ring holes are provided at the bottom of the spray disc high-pressure air cavity, and the plurality of high-pressure jet ring holes are arranged at equal intervals circumferentially. A high-pressure air inlet pipe is connected to one side of the top of the spray disc high-pressure air cavity, a spray disc guide hole is provided in the center of the spray disc upper plate, and the spray disc guide hole is arranged through the spray disc lower plate. The discharge end of the guide nozzle is inserted into the spray disc guide hole, and the plurality of high-pressure jet ring holes are arranged toward the discharge end of the guide nozzle.

[0038] Preferably, the ultrasonic vibration part includes an ultrasonic transducer and an ultrasonic concentrator, and the ultrasonic concentrator is fixed to the bottom of the lower plate of the spray disc;

[0039] The ultrasonic concentrator is fixedly connected to the ultrasonic transducer.

[0040] Preferably, the powder collection system includes a powder cooling pipe, the feed end of the powder cooling pipe is connected to the discharge end of the atomizing cone section located at the bottom, the discharge end of the powder cooling pipe is connected to a cyclone separator, a tail exhaust valve, a tail exhaust pipeline and an axial flow fan in sequence, and the discharge end of the cyclone separator is connected to a powder collection tank.

[0041] Compared with the prior art, the present invention has the following advantages and technical effects:

[0042] (1) At present, aerosol powder making equipment with a guide nozzle is prone to nozzle clogging during production, which affects the powder making efficiency. In the matrix ultrasonic atomization powder making system of the present invention, the ultrasonic concentrator amplifies the particle displacement and velocity, and transmits the ultrasonic energy to the guide hole in the center of the atomizing spray disk. The mechanical vibration in the guide tube during the powder making process can prevent the alloy liquid from clogging.

[0043] (2) In the current stage of production, aerosol powder making equipment with a guide nozzle will produce sheet-like and layered accumulation nodules around the high-pressure air injection ring hole of the aerosol spray disc after long-term production. In the ultrasonic atomization powder making system of the present invention, the spray disc is in a high-frequency oscillation state during production, and the spray disc atomization area is in a coupled ultrasonic energy field, which prevents the accumulation and condensation of liquid metal mist on the spray disc and the formation of accumulation nodules.

[0044] (3) The traditional aerosol powder making method has a low yield of 15-53um powder, poor sphericity, and many satellite powders, which is not suitable for direct use in powder metallurgy fields such as electron beam selective melting, laser 3D printing melting, and hot isostatic pressing. In addition, contact ultrasonic powder making is limited by the service life of the ultrasonic vibration head material in actual working conditions and the vibration frequency is generally not higher than 45KHz, which makes the production capacity and fine powder yield in the actual production process relatively low. The present invention adopts a matrix-coupled arrangement of non-contact high-frequency vibration combined with high-pressure atomization to give the high-pressure aerosol spray disc system matrix-coupled high-frequency vibration potential energy, fully crush the alloy melt, and solve the problem of low yield of 15-53um fine powder.

[0045] (4) The matrix-coupled high-frequency ultrasonic vibration system applies ultrasonic waves in the atomization zone to increase the surface tension of the molten droplets and promote the rapid spheroidization of the droplets. At the same time, it increases the supercooling degree to make it solidify quickly, solving the problems of poor sphericity and many satellite balls. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0047] Figure 1 It is a schematic diagram of the structure of the present invention;

[0048] Figure 2 It is a side view of the present invention;

[0049] Figure 3 This is a cross-sectional view of the tundish structure of the present invention;

[0050] Figure 4 This is a cross-sectional view of the ultrasonic atomization powder making system of the present invention;

[0051] Figure 5 This is a top view of the ultrasonic atomization powder making system of the present invention;

[0052] Figure 6 This is a distribution diagram of the ultrasonic radiation rods of the present invention;

[0053] Among them: 1. Vacuum system; 101. High vacuum pump group; 102. Vacuum pipeline; 103. Low vacuum pump group; 2. Melting system; 201. Main melter; 202. Tundish; 2021. Tundish crucible; 2022. Tundish temperature control thermocouple; 2023. Cap; 2024. Support plate; 2025. Support column; 2026. Induction coil; 2027. Graphite heating ring; 203. Tundish power supply; 204. Main melting power supply; 205. Turning hydraulic cylinder; 3. Ultrasonic atomization powder making system; 301. Ultrasonic radiation rod; 302. Ultrasonic wave; 303. Guide Nozzle; 304, atomizing spray disc; 3041, spray disc upper plate; 3042, spray disc high-pressure air cavity; 3043, spray disc lower plate; 3044, high-pressure jet ring hole; 3045, high-pressure air inlet pipe; 3046, spray disc guide hole; 305, ultrasonic transducer; 306, ultrasonic concentrator; 4, powder collection system; 401, powder cooling pipe; 402, powder collection tank; 405, cyclone separator; 407, tail exhaust valve; 408, tail exhaust pipeline; 409, axial flow fan; 5, vacuum chamber; 501, atomizing cone section; 502, atomizing chamber; 503, melting chamber; 504, melting chamber furnace cover. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0055] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] Reference Figures 1 to 6 The present invention discloses a method for ultrasonically preparing ultrafine metal powder, comprising the following steps:

[0057] Step 1: preparing the molten alloy liquid;

[0058] Step 2: Apply supersonic gas at the atomizing nozzle to atomize the molten alloy liquid into fine droplets;

[0059] Step 3: Simultaneously with step 2, a high-frequency vibration field is applied to the atomizing nozzle;

[0060] Step 4: Simultaneously with step 3, apply ultrasonic waves to the center area of the milling process.

[0061] During use, a high-frequency vibration field is applied to the atomizing nozzle. When the amplitude reaches a certain value, the molten steel at the nozzle generates droplets at the wave crest under the influence of tension waves. Under the influence of ultrasonic frequencies, the droplets detach from the peaks of the liquid flow amplitude, causing the alloy steel liquid to atomize from the liquid phase into nanometer-sized droplets. In ultrasonic gas atomization, the molten metal stream is impacted and fragmented by multiple high-speed gas pulses. Simultaneously, supersonic gas is applied to the nozzle to further refine the droplets and create conditions for powder condensation. Simultaneously, ultrasonic waves are applied to the center of the powder production area to overcome the formation of satellite powders.

[0062] An ultrafine metal powder ultrasonic preparation system, based on the above-mentioned ultrafine metal powder ultrasonic preparation method, comprises:

[0063] Vacuum chamber 5;

[0064] The vacuum system 1 is connected to one side of the vacuum chamber 5 and is used to maintain the vacuum environment in the vacuum chamber 5;

[0065] The smelting system 2 is arranged in the vacuum chamber 5 and is used for preparing the molten alloy liquid;

[0066] The ultrasonic atomization powder making system 3 is arranged in the vacuum chamber 5, and the discharge end of the ultrasonic atomization powder making system 3 is connected to the discharge end of the smelting system 2, and is used to divide the molten alloy liquid into metal powder balls;

[0067] The powder collecting system 4 is connected to the discharge end of the vacuum chamber 5 and is used to collect the prepared metal powder balls.

[0068] The equipment mainly consists of a vacuum chamber 5, a smelting system 2, an ultrasonic atomization powder making system 3, a vacuum system 1 and a powder collecting system 4.

[0069] Different operating platforms can be configured around the furnace body of the vacuum chamber 5 according to needs.

[0070] Different vacuum systems 1 can be configured according to the vacuum degree and evacuation rate required for smelting.

[0071] A front-opening door can be provided in front of the vacuum chamber 5 according to smelting requirements.

[0072] According to a further optimized solution, the vacuum chamber 5 includes a smelting chamber 503, an atomizing chamber 502, and an atomizing cone section 501, which are sequentially connected from top to bottom. The top of the smelting chamber 503 is movably connected to a smelting chamber furnace cover 504. There are at least one atomizing chamber 502 and at least one atomizing cone section 501.

[0073] The vacuum system 1 is connected to one side of the smelting chamber 503 or the atomizing chamber 502;

[0074] The smelting system 2 is located in the smelting chamber 503;

[0075] The ultrasonic atomization powder making system 3 is located in the smelting chamber 503, and the discharge end of the ultrasonic atomization powder making system 3 is set in the atomization chamber 502;

[0076] The discharge end of the atomizing cone section 501 is connected to the feed end of the powder collecting system 4 .

[0077] The vacuum chamber consists of a melting chamber cover, a melting chamber, an atomizing chamber, and an atomizing cone section.

[0078] The melting chamber lid 504 is hingedly connected to the melting chamber 503. The atomizing chamber 502 can be divided into multiple sections and fixed below the melting chamber 503, all connected by bolts or clamp bolts. The atomizing cone 501 can be divided into multiple sections and fixed below the atomizing chamber 502, all connected by bolts or clamp bolts. The melting chamber front door can be hinged to an opening in the melting chamber side wall. Rubber rings are used to seal the various interfaces and flanges of the vacuum chamber 5 to ensure the overall sealing performance of the equipment.

[0079] According to a further optimized solution, the smelting system 2 includes a main smelter 201 and a tundish 202 disposed in the smelting chamber 503;

[0080] The main smelter 201 is electrically connected to a main smelting power supply 204;

[0081] The tundish 202 is electrically connected to a tundish power supply 203;

[0082] The main smelter 201 is fixedly connected to the output shaft of the tilting hydraulic cylinder 205, and the fixed end of the tilting hydraulic cylinder 205 is hinged on the side wall of the smelting chamber 503; the tilting hydraulic cylinder 205 is used to tilt the main smelter 201;

[0083] The tundish 202 is fixedly connected to the smelting chamber 503;

[0084] After the main smelter 201 is turned over, the discharge end of the main smelter 201 is located directly above the feed end of the tundish 202;

[0085] The discharge end of the tundish 202 is connected to the feed end of the ultrasonic atomization powder making system 3 .

[0086] The electrode is rotatably arranged in the smelting chamber 503 through a bearing. One end of the electrode located in the smelting chamber 503 is connected to the middle of the main smelter 201 through a flange, and the other end of the electrode located outside the smelting chamber 503 is connected to the main smelting power supply 204. The main smelting power supply 204 and the main smelting vessel 201 are electrically connected through the electrode.

[0087] In a further optimized solution, the tundish 202 includes a support plate 2024, which is fixed to the bottom of the smelting chamber 503 via a plurality of support columns 2025. A cap 2023 is fixed to the top of the support plate 2024, and a tundish crucible 2021 is fixed to the bottom of the support plate 2024. The tundish crucible 2021 is in communication with the cap 2023.

[0088] The tundish crucible 2021 is wrapped with a graphite heating ring 2027, which is wrapped with an insulation layer, which is wrapped with an induction coil 2026. A plurality of tundish temperature-controlling thermocouples 2022 for controlling the temperature in the tundish crucible 2021 are inserted into the graphite heating ring 2027. The tundish temperature-controlling thermocouples 2022 are electrically connected to the tundish power supply 203.

[0089] The bottom of the tundish crucible 2021 is connected to the feed end of the ultrasonic atomization powder making system 3.

[0090] Further optimized, the ultrasonic atomization powder making system 3 includes a guide nozzle 303, the feed end of the guide nozzle 303 is connected to the bottom of the tundish crucible 2021, and the discharge end of the guide nozzle 303 is connected to the middle of the atomizing spray disc 304;

[0091] An ultrasonic airflow jetting portion is provided in the atomizing spray disc 304, and the nozzle of the ultrasonic airflow jetting portion is arranged toward the discharge end of the flow guide nozzle 303;

[0092] The bottom of the atomizing spray disc 304 is provided with an ultrasonic vibration part;

[0093] A plurality of ultrasonic radiation rods 301 are provided below the atomizing spray disc 304 . The ultrasonic radiation rods 301 are fixed to the inner wall of the atomizing chamber 502 at the top at equal intervals in the circumferential direction. The emission ends of the ultrasonic radiation rods 301 are arranged toward the discharge end of the guide nozzle 303 .

[0094] The smelting system includes a main smelter 201, a main smelting power supply 204, a tundish 202, a tundish power supply 203, and a tilting hydraulic cylinder 205. The main smelting power supply 204 is connected to the main smelter 201 via electrodes and provides the required electrical energy for smelting. The tundish power supply 203 is connected to the tundish 202 via electrodes and provides the required electrical energy for melt insulation and superheating.

[0095] The cap 2023 of the tundish 202 is bolted to the support plate 2024 at its support point. The cap 2023 sits on the support plate 2024, and the support column 2025 sits on the bottom of the smelting chamber 503. The flow nozzle 303 is concentric with the tundish crucible 2021. The flow nozzle 303 is inserted into the flow nozzle hole at the bottom of the tundish crucible 2021 and into the center hole of the atomizing nozzle plate 304. The tundish crucible 2021 is covered with a graphite heating ring 2027, which is covered with an insulation layer. An induction coil 2026 is placed outside the insulation layer. A tundish thermocouple 2022 is inserted into the graphite heating ring 2027 for temperature control. One end of the tilting hydraulic cylinder 205 is hinged to the platform, and the other end is connected to a coaxial electrode.

[0096] Further optimized, the atomizing spray disc 304 includes a spray disc upper plate 3041 and a spray disc lower plate 3043, and the ultrasonic air flow injection portion is located between the spray disc upper plate 3041 and the spray disc lower plate 3043;

[0097] The ultrasonic air flow injection portion includes a nozzle disc high-pressure air cavity 3042, which is located between the nozzle disc upper plate 3041 and the nozzle disc lower plate 3043. A plurality of high-pressure jet ring holes 3044 are provided at the bottom of the nozzle disc high-pressure air cavity 3042. The plurality of high-pressure jet ring holes 3044 are arranged at equal intervals circumferentially. A high-pressure air inlet pipe 3045 is connected to one side of the top of the nozzle disc high-pressure air cavity 3042. A nozzle disc guide hole 3046 is provided in the center of the nozzle disc upper plate 3041. The nozzle disc guide hole 3046 is arranged through the nozzle disc lower plate 3043. The discharge end of the guide nozzle 303 is inserted into the nozzle disc guide hole 3046. The plurality of high-pressure jet ring holes 3044 are arranged toward the discharge end of the guide nozzle 303.

[0098] According to a further optimized solution, the ultrasonic vibration part includes an ultrasonic transducer 305 and an ultrasonic concentrator 306, and the ultrasonic concentrator 306 is fixed to the bottom of the spray disc lower plate 3043;

[0099] The ultrasonic concentrator 306 is fixedly connected to the ultrasonic transducer 305 .

[0100] The ultrasonic atomization powder making system 3 includes a high-pressure gas circuit system, a high-frequency vibration atomization spray disc and an ultrasonic radiation system.

[0101] High frequency vibration aerosol spray disc:

[0102] A guide hole and a nozzle guide hole 3046 are respectively provided at the bottom of the tundish 202 and in the center of the atomizing nozzle disc 304. The guide nozzle 303 is inserted into the guide hole and nozzle guide hole 3046. The atomizing nozzle disc 304 consists of a concentrically arranged outer wall and inner wall, which are sealed to the inner and outer walls by the upper and lower nozzle disc plates 3041 and 3043, respectively. The inner cavity is the nozzle disc high-pressure air chamber 3042, with the nozzle disc guide hole 3046 at its center.

[0103] Below the high-pressure air cavity 3042, where the lower plate 3043 meets the nozzle guide hole 3046, a high-pressure air jet ring hole 3044 is provided to form a supersonic air blade. The nozzle high-pressure air cavity 3042 is connected to a high-pressure air inlet pipe 3045. The atomizing nozzle is mounted at the bottom of the smelting chamber 503, with the nozzle guide hole 3046 concentric with the center of the atomizing chamber 502.

[0104] The atomizing spray disc 304 is mounted on the ultrasonic concentrator 306 through mounting holes. The ultrasonic concentrator 306 is fixedly connected to the vibrating portion of the ultrasonic transducer 305. A ceramic-sealed electrode is mounted on the sidewall of the smelting chamber 503 and electrically connected to the ultrasonic transducer 305, serving as the input for high-frequency electrical energy oscillation. The ultrasonic transducer 305 converts the high-frequency electrical oscillation signal into mechanical vibration, converting electrical energy into high-frequency vibration. The ultrasonic concentrator 306 amplifies the particle displacement and velocity of the mechanical vibration, concentrating the ultrasonic energy on the spray disc's guide holes 3046.

[0105] High pressure gas system:

[0106] The high-pressure air inlet pipe 3045 is used to transmit high-pressure process gas. The high-pressure main air inlet end of the high-pressure air inlet pipe 3045 is connected to the air supply source. The high-pressure air cavity 3042 of the spray plate is connected to the high-pressure air inlet pipe 3045.

[0107] The smelting chamber's inflation and deflation pipes connect to smelting chamber 503. High-pressure electric ball valves and pressure transmitters are installed in series in these pipes. A PLC controller receives the pressure signal from the pressure transmitter and, based on the process's required pressure signal as a target value, controls the opening and closing angles of the electric ball valves, thereby adjusting the high-pressure gas pressure at the corresponding position.

[0108] High-pressure gas flows through the high-pressure air chamber 3042 of the spray plate and the high-pressure air ring 3044 to form a high-pressure air blade. By adjusting the gas pressure, the gas flow rate and flow velocity of the supersonic air blade can be controlled. The high-pressure gas system can also control the pressure between the atomizing chamber 502 and the melting chamber 503, further controlling the liquid flow rate by creating a pressure differential.

[0109] Ultrasonic radiation system:

[0110] The atomizing chamber 502 is connected to the smelting chamber 503 at a position (i.e., near the supersonic gas atomization area), and the side wall is provided with an even number of ultrasonic radiation rod interfaces, preferably 4 in this embodiment. The ultrasonic radiation rods 301 are installed at the ultrasonic generator interface of the atomizing chamber 502 side wall, opposite to each other. The excitation power supply is electrically connected to the transducer, and the transducer is fixed to the ultrasonic radiation rods 301. The electric oscillation signal sent from the excitation power supply will cause changes in the electric field and magnetic field in the electrical energy storage element in the transducer. The changes in the electric field and magnetic field of the electrical energy storage element produce a driving force on the mechanical vibration system of the transducer, causing the transducer to enter a vibrating state, thereby causing the ultrasonic radiation rods 301 in contact with the mechanical vibration system of the transducer to vibrate, and radiate ultrasonic waves 302 into the argon gas toward the center area of pulverizing.

[0111] To further optimize the solution, the powder collection system 4 includes a powder cooling pipe 401, the feed end of the powder cooling pipe 401 is connected to the discharge end of the atomizing cone section 501 located at the bottom, the discharge end of the powder cooling pipe 401 is connected in sequence to the cyclone separator 405, the tail exhaust valve 407, the tail exhaust pipeline 408 and the axial flow fan 409, and the discharge end of the cyclone separator 405 is connected to the powder collection tank 402.

[0112] The powder collection system 4 includes a powder cooling pipe 401, a cyclone separator 405, a powder collection tank 402, a tail exhaust valve 407, a tail exhaust pipe 408, and an axial flow fan 409. The powder cooling pipe 401 is connected to the bottom of the atomizing cone section 501, and the cyclone separator 405, tail exhaust valve 407, tail exhaust pipe 408, and axial flow fan 409 are connected in series at the rear. The cyclone separator 405 consists of an outer cylinder, a cyclone chamber, an exhaust pipe, and a powder collection cone. The exhaust port and powder collection cone are concentric with the outer cylinder, and a cyclone chamber is formed between the outer cylinder and the exhaust pipe. The powder cooling pipe is eccentrically connected to the outer cylinder of the cyclone separator. The powder collection cone has an opening below and is connected to the powder collection tank 402.

[0113] The vacuum system 1 consists of a vacuum pump assembly and vacuum piping 102. The vacuum pump assembly includes a high vacuum pump assembly 101 and a low vacuum pump assembly 103. Both the high vacuum pump assembly 101 and the low vacuum pump assembly 103 are connected to the melting chamber 503 or the atomization chamber 502 via vacuum piping 102. This provides a vacuum environment for melting and atomization. Smelting under vacuum effectively reduces the oxygen content in the molten steel and powder.

[0114] The present invention has the following advantages:

[0115] (1) At present, aerosol powder making equipment with a guide nozzle is prone to nozzle clogging during production, which affects the powder making efficiency. In the matrix ultrasonic atomization powder making system of the present invention, the ultrasonic concentrator amplifies the particle displacement and velocity, and transmits the ultrasonic energy to the guide hole in the center of the atomizing spray disk. The mechanical vibration in the guide tube during the powder making process can prevent the alloy liquid from clogging.

[0116] (2) In the current stage of production, aerosol powder making equipment with a guide nozzle will produce sheet-like and layered accumulation nodules around the high-pressure air injection ring hole of the aerosol spray disc after long-term production. In the ultrasonic atomization powder making system of the present invention, the spray disc is in a high-frequency oscillation state during production, and the spray disc atomization area is in a coupled ultrasonic energy field, which prevents the accumulation and condensation of liquid metal mist on the spray disc and the formation of accumulation nodules.

[0117] (3) The traditional aerosol powder making method has a low yield of 15-53um powder, poor sphericity, and many satellite powders, which is not suitable for direct use in powder metallurgy fields such as electron beam selective melting, laser 3D printing melting, and hot isostatic pressing. In addition, contact ultrasonic powder making is limited by the service life of the ultrasonic vibration head material in actual working conditions and the vibration frequency is generally not higher than 45KHz, which makes the production capacity and fine powder yield in the actual production process relatively low. The present invention adopts a matrix-coupled arrangement of non-contact high-frequency vibration combined with high-pressure atomization to give the high-pressure aerosol spray disc system matrix-coupled high-frequency vibration potential energy, fully crush the alloy melt, and solve the problem of low yield of 15-53um fine powder.

[0118] (4) The matrix-coupled high-frequency ultrasonic vibration system applies ultrasonic waves in the atomization zone to increase the surface tension of the molten droplets and promote the rapid spheroidization of the droplets. At the same time, it increases the supercooling degree to make it solidify quickly, solving the problems of poor sphericity and many satellite balls.

[0119] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0120] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for ultrasonically preparing ultrafine metal powder, characterized in that: The steps include: Step 1: preparing the molten alloy liquid; Step 2: Apply supersonic gas at the atomizing nozzle to atomize the molten alloy liquid into fine droplets; Step 3: Simultaneously with step 2, a high-frequency vibration field is applied to the atomizing nozzle; Step 4: Simultaneously with step 3, apply ultrasonic waves to the center of the milling process; An ultrafine metal powder ultrasonic preparation system, comprising: Vacuum chamber (5); A vacuum system (1) is connected to one side of the vacuum chamber (5) and is used to maintain a vacuum environment in the vacuum chamber (5); A smelting system (2), arranged in the vacuum chamber (5), is used for preparing a molten alloy liquid; An ultrasonic atomization powder making system (3) is arranged in the vacuum chamber (5), and a discharge end of the ultrasonic atomization powder making system (3) is connected to a discharge end of the smelting system (2) and is used to divide the molten alloy liquid into metal powder balls; A powder collecting system (4) is connected to the discharge end of the vacuum chamber (5) and is used to collect the prepared metal powder balls; The vacuum chamber (5) comprises a smelting chamber (503), an atomizing chamber (502) and an atomizing cone section (501) which are sequentially connected from top to bottom, and the top of the smelting chamber (503) is movably connected to a smelting chamber furnace cover (504); The vacuum system (1) is connected to one side of the smelting chamber (503) or the atomization chamber (502); The smelting system (2) is located in the smelting chamber (503); The ultrasonic atomization powder making system (3) is located in the smelting chamber (503), and the discharge end of the ultrasonic atomization powder making system (3) is arranged in the atomization chamber (502); the discharge end of the atomization cone section (501) is connected to the feed end of the powder collecting system (4); The smelting system (2) includes a main smelter (201) and a tundish (202) arranged in the smelting chamber (503); The main smelter (201) is electrically connected to a main smelting power supply (204); The tundish (202) is electrically connected to a tundish power supply (203); The main smelter (201) is fixedly connected to the output shaft of a tilting hydraulic cylinder (205), and the fixed end of the tilting hydraulic cylinder (205) is hinged on the side wall of the smelting chamber (503); the tilting hydraulic cylinder (205) is used for tilting the main smelter (201); The tundish (202) is fixedly connected in the smelting chamber (503); After the main smelter (201) is turned over, the discharge end of the main smelter (201) is located directly above the feed end of the tundish (202); The discharge end of the tundish (202) is in communication with the feed end of the ultrasonic atomization powder making system (3); The tundish (202) comprises a support plate (2024), the support plate (2024) being fixedly connected to the bottom of the smelting chamber (503) via a plurality of support columns (2025), a cap opening (2023) being fixedly connected to the top of the support plate (2024), a tundish crucible (2021) being fixedly connected to the bottom of the support plate (2024), and the tundish crucible (2021) being in communication with the cap opening (2023); The outer side of the tundish crucible (2021) is wrapped with a graphite heating ring (2027), the outer side of the graphite heating ring (2027) is wrapped with a thermal insulation layer, the outer side of the thermal insulation layer is wrapped with an induction coil (2026), and a plurality of tundish temperature-controlling thermocouples (2022) for controlling the temperature inside the tundish crucible (2021) are inserted into the graphite heating ring (2027), and the tundish temperature-controlling thermocouples (2022) are electrically connected to the tundish power supply (203); The bottom of the tundish crucible (2021) is in communication with the feed end of the ultrasonic atomization powder making system (3); The ultrasonic atomization powder making system (3) comprises a guide nozzle (303), the feed end of the guide nozzle (303) is in communication with the bottom of the tundish crucible (2021), and the discharge end of the guide nozzle (303) is in communication with the middle of the atomizing spray disc (304); An ultrasonic airflow jet portion is provided in the atomizing spray disc (304), and the nozzle of the ultrasonic airflow jet portion is arranged toward the discharge end of the guide nozzle (303); The bottom of the atomizing spray disc (304) is provided with an ultrasonic vibration part; A plurality of ultrasonic radiation rods (301) are provided below the atomizing spray disc (304), and the plurality of ultrasonic radiation rods (301) are fixedly connected to the inner wall of the atomizing chamber (502) at the top at equal intervals in the circumferential direction, and the emitting ends of the ultrasonic radiation rods (301) are arranged toward the discharge end of the guide nozzle (303); The atomizing spray disc (304) comprises a spray disc upper plate (3041) and a spray disc lower plate (3043), and the ultrasonic airflow jet portion is located between the spray disc upper plate (3041) and the spray disc lower plate (3043); The ultrasonic airflow injection portion comprises a nozzle disc high-pressure air cavity (3042), the nozzle disc high-pressure air cavity (3042) is located between the nozzle disc upper plate (3041) and the nozzle disc lower plate (3043), a plurality of high-pressure jet ring holes (3044) are provided at the bottom of the nozzle disc high-pressure air cavity (3042), the plurality of high-pressure jet ring holes (3044) are arranged at equal intervals in the circumferential direction, a high-pressure air inlet pipe (3045) is connected to one side of the top of the nozzle disc high-pressure air cavity (3042), a nozzle disc guide hole (3046) is provided in the center of the nozzle disc upper plate (3041), the nozzle disc guide hole (3046) is arranged through the nozzle disc lower plate (3043), the discharge end of the guide nozzle (303) is inserted into the nozzle disc guide hole (3046), and the plurality of high-pressure jet ring holes (3044) are arranged towards the discharge end of the guide nozzle (303); The ultrasonic vibration part includes an ultrasonic transducer (305) and an ultrasonic energy concentrator (306), and the ultrasonic energy concentrator (306) is fixed to the bottom of the spray disc lower plate (3043); The ultrasonic concentrator (306) is fixedly connected to the ultrasonic transducer (305).

2. The ultrafine metal powder ultrasonic preparation system according to claim 1, characterized in that: The powder collecting system (4) includes a powder cooling pipe (401), the feed end of the powder cooling pipe (401) is connected to the discharge end of the atomizing cone section (501) located at the bottom, the discharge end of the powder cooling pipe (401) is connected in sequence to a cyclone separator (405), a tail discharge valve (407), a tail discharge pipeline (408) and an axial flow fan (409), and the discharge end of the cyclone separator (405) is connected to a powder collecting tank (402).

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