Metal powder atomization equipment

Abstract

The invention discloses metal powder atomizing equipment, and belongs to the technical field of metal additive manufacturing, the metal powder atomizing equipment comprises a smelting chamber and an atomizing chamber, the smelting chamber is used for smelting alloy master batch into liquid metal melt; the atomizing chamber comprises a flow guide nozzle, an LAVAL pipe and a centrifugal rotating disc. An outlet in the tail end of the flow guide nozzle is located in the throat section of the LAVAL pipe, and the throat section is perpendicularly arranged relative to the horizontal plane. The LAVAL pipe is used for forming stable air pressure in the throat section by connecting an air source, pre-crushing the metal melt in the throat section, and downwards outputting the metal melt in the throat section after pre-crushing; the centrifugal rotating disc is located under the LAVAL pipe, and the centrifugal rotating disc is used for receiving the metal melt output from the LAVAL pipe and atomizing the metal melt. According to the metal powder atomization equipment, the problems that the centrifugal atomization effect is affected and a pump set is damaged due to fluctuation of the air pressure below the flow guide nozzle in the metal melt conveying process in existing equipment are solved, the air pressure of an outlet in the tail end of the flow guide nozzle is controllable, and it is ensured that the metal melt is stably and reliably supplied.

Description

Technical Field

[0001] The invention belongs to the technical field of metal additive manufacturing, and in particular relates to a metal powder atomization device. Background Art

[0002] In recent years, the application scale of metal additive manufacturing technology in aerospace, automobile manufacturing, biomedicine, industrial molds and other fields has continued to grow, and the consumption of metal powder raw materials for metal additive manufacturing has also increased accordingly. Due to the narrow particle size distribution, high sphericity, and less satellite powder and hollow powder of the prepared metal powder, the turntable centrifugal atomization process has great technical potential and application value in the field of metal powder production for metal additive manufacturing. The combined atomization process uses an atomizing spray disc to first transform the metal melt column flowing out of the end of the guide nozzle into a large number of tiny metal droplets, and then the gas-liquid mixture falls on the centrifugal turntable, thereby forming an extremely thin and uniform metal melt liquid film, and then the metal melt liquid film is atomized into tiny metal droplets by the centrifugal turntable to complete the centrifugal atomization operation.

[0003] However, when the atomizing spray disc breaks up the molten metal produced by the guide nozzle, a reflow zone will appear under the guide nozzle. The air pressure in the reflux zone fluctuates significantly with the progress of the atomization operation, which in turn causes the flow rate of the molten metal produced by the guide nozzle to fluctuate significantly, thus affecting the centrifugal atomization effect.

[0004] In addition, high-temperature molten metal is often difficult to supply by pumping. Even if it can be supplied by pumping, the pressure fluctuations in the reflux area below the guide nozzle will be transmitted back to the pump unit, causing the pump unit to be frequently subjected to vibration and impact, thereby significantly increasing the risk of pump unit failure.

[0005] Therefore, the existing technology needs to be improved and developed. Summary of the invention

[0006] The purpose of the present invention is to provide a metal powder atomization equipment to solve the problem that in the existing equipment, the centrifugal atomization effect is affected by the air pressure fluctuation at the outlet of the guide nozzle during the metal melt conveying process and the pump group is damaged, so that the air pressure at the end outlet of the guide nozzle can be controlled to ensure the stable and reliable supply of the metal melt.

[0007] In a first aspect, the present invention provides a metal powder atomization device, comprising: A smelting chamber, wherein the smelting chamber is used to smelt the alloy mother material into a liquid metal melt; An atomization chamber, the atomization chamber comprising a guide nozzle, a LAVAL tube and a centrifugal turntable, the guide nozzle connecting the smelting chamber and the LAVAL tube, the terminal outlet of the guide nozzle being located at the throat section of the LAVAL tube and the throat section being arranged vertically relative to a horizontal plane, the guide nozzle being used to guide the molten metal to the interior of the throat section; the LAVAL tube being used to form a stable air pressure in the throat section by connecting to an air source, and to pre-crush the molten metal flowing out of the guide nozzle, and to output the molten metal in the throat section downwardly after the pre-crushing; the centrifugal turntable being located directly below the LAVAL tube, and being used to receive the molten metal output from the LAVAL tube and to atomize the molten metal.

[0008] The metal powder atomization equipment provided by the present invention controls the air pressure at the outlet of the guide nozzle end by utilizing the characteristic that the air pressure in the throat section of the LAVAL tube has higher controllability, thereby avoiding fluctuations in the metal melt conveying process, thereby ensuring the centrifugal atomization effect and ensuring stable and reliable supply.

[0009] Furthermore, the LAVAL tube includes an outer shell that encloses a flow channel, and the outer shell as a multi-layer structure includes an inner layer, an insulation layer and a protective layer from the inside to the outside; the inner layer is made of a high temperature resistant and corrosion resistant material; the insulation layer is made of a insulation material; and the protective layer is made of a protective material.

[0010] The three-layer structure cooperates with each other to ensure the stable operation of the LAVAL tube in high temperature and corrosive environment, and improves the working efficiency and product quality of the metal powder atomization equipment.

[0011] Furthermore, the flow channel includes an air chamber, an inlet section, the throat section and an outlet section which are connected in sequence, the cross-sectional area of ​​the air chamber is constant and larger than the cross-sectional area of ​​the throat section, and the air chamber is used to connect to the air source; the cross-sectional area of ​​the inlet section gradually decreases toward the throat section; the cross-sectional area of ​​the throat section is constant; the cross-sectional area of ​​the outlet section gradually increases toward the throat section, and the outlet section is used to output the molten metal.

[0012] The risk of equipment damage caused by the use of mechanical pumping is avoided. At the same time, by precisely controlling the air pressure environment, the problem of unstable metal melt flow caused by air pressure fluctuations in the reflow zone below the guide nozzle is effectively solved.

[0013] Furthermore, the flow channel includes an air chamber, an inlet section, the throat section, an outlet section and a stable section which are connected in sequence, the cross-sectional area of ​​the air chamber is constant and larger than the cross-sectional area of ​​the throat section, and the air chamber is used to connect to the air source; the cross-sectional area of ​​the inlet section gradually decreases toward the throat section; the cross-sectional area of ​​the throat section is constant; the cross-sectional area of ​​the outlet section gradually increases toward the throat section; the cross-sectional area of ​​the stable section is constant, and the stable section is used to output the molten metal.

[0014] The design of the stabilization section can further stabilize the flow of the metal melt and reduce flow fluctuations, thereby ensuring that the metal melt is stably output to the centrifugal turntable. Through this design, the metal powder atomization equipment of the present application can effectively reduce fluctuations in the flow of the metal melt.

[0015] Furthermore, the relationship between the outlet inner diameter of the outlet section and the diameter of the centrifugal turntable satisfies: ; in, is the outlet inner diameter of the outlet section, is the height distance between the LAVAL tube and the centrifugal turntable, is the expansion angle of the outlet section, is the diameter of the centrifugal turntable, is a preset constant less than 1.

[0016] Furthermore, the relationship between the outlet inner diameter of the stabilizing section and the diameter of the centrifugal turntable satisfies: ; in, is the outlet inner diameter of the stabilizing section, is the diameter of the centrifugal turntable, is a preset constant less than 1.

[0017] Furthermore, the size of the throat section satisfies: ; in, is the outer diameter of the guide nozzle, is the inner diameter of the throat section.

[0018] Furthermore, the air pressure of the throat section satisfies: ; in, is the air pressure in the throat section, is the air pressure at the inlet section, is the gas adiabatic coefficient.

[0019] Furthermore, it also includes a cyclone separator, a dust collector, a return fan and a heater which are connected in sequence, the cyclone separator is connected to the atomization chamber and is used to separate particles in the gas output by the atomization chamber; the dust collector is used to separate particles in the gas output by the cyclone separator; the return fan is used to pressurize the gas output by the dust collector; the heater is used to heat the gas output by the return fan, and the heater is connected to the LAVAL pipe so that the pressurized and heated gas can be connected to the LAVAL pipe as a gas source.

[0020] Furthermore, the guide nozzle is integrated with the housing as a bypass of the flow channel.

[0021] From the above, it can be seen that the metal powder atomization equipment of the present invention utilizes a LAVAL tube to output the molten metal. On the one hand, the LAVAL tube can provide a stable and controllable air pressure for the end outlet of the guide nozzle, thereby avoiding fluctuations in the metal melt during the transportation process. On the other hand, the LAVAL tube realizes the output of the molten metal and reduces the risk of its failure while overcoming the influence of fluctuations, making the supply process more stable and reliable. In addition, the airflow in the LAVAL tube will pre-crush the molten metal, which is beneficial for the metal melt to form an extremely thin and uniform metal melt liquid film on the surface of the centrifugal turntable, and thus is beneficial for obtaining a higher quality atomized powder.

[0022] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or be understood by implementing the embodiments of the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic structural diagram of a metal powder atomization device provided in an embodiment of the present invention.

[0024] Figure 2 4 is a cross-sectional view of a LAVAL tube in an embodiment of the present invention.

[0025] Figure 3 Parameter design diagram of the LAVAL tube without a stabilization section in an embodiment of the present invention.

[0026] Figure 4 Parameter design diagram of the LAVAL tube with a stabilization section in an embodiment of the present invention.

[0027] Figure 5 Parameter design diagram of the guide nozzle and the LAVAL tube with a stabilizing section in an embodiment of the present invention.

[0028] Figure 6It is a cross-sectional view of a LAVAL pipe with a guide nozzle as a bypass in an embodiment of the present invention.

[0029] Description of labels: 100, smelting chamber; 200, atomizing chamber; 210, guide nozzle; 220, LAVAL tube; 221, throat section; 222, shell; 223, air chamber; 224, inlet section; 225, outlet section; 226, stabilizing section; 230, centrifugal turntable; 240, rotary drive; 250, support base; 300, cyclone separator; 400, dust collector; 500, return air fan; 600, heater. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, 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 limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0032] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0035] Reference Figure 1 The present invention provides a metal powder atomization device, comprising: A smelting chamber 100, wherein the smelting chamber 100 is used to smelt the alloy mother material into a liquid metal melt; Atomization chamber 200, the atomization chamber 200 includes a guide nozzle 210, a LAVAL tube 220 and a centrifugal turntable 230, the guide nozzle 210 connects the smelting chamber 100 and the LAVAL tube 220, the end outlet of the guide nozzle 210 is located at the throat section 221 of the LAVAL tube 220 and the throat section 221 is arranged vertically relative to the horizontal plane, the guide nozzle 210 is used to guide the metal melt to the inside of the throat section 221; the LAVAL tube 220 is used to connect to the air source to form a stable air pressure in the throat section 221, and pre-crush the metal melt flowing out of the guide nozzle 210, and output the metal melt in the throat section 221 downward after pre-crushing; the centrifugal turntable 230 is located directly below the LAVAL tube 220, and the centrifugal turntable 230 is used to receive the metal melt output from the LAVAL tube 220 and atomize the metal melt.

[0036] In this embodiment, the LAVAL tube is also called the Laval tube, which is different from the Venturi tube. The overall structural shape of the Venturi tube is a symmetrical pipe that contracts in the middle and gradually expands at both ends (such as smoothly recovering to an hourglass shape close to the original diameter after contraction). It specifically includes a throat section and a gradually expanding section, and there is no expansion section. The internal pressure changes as inlet high pressure-throat section low pressure-outlet pressure recovery, wherein the gradually expanding section is only used to restore the pressure. Therefore, the internal fluid velocity is subsonic throughout the entire process. The Venturi tube is generally used to control the fluid flow rate.

[0037] The overall structural shape of the Laval tube is an axisymmetric pipe that first contracts and then expands (such as a trumpet shape that expands significantly after contraction), specifically including a throat section and an expansion section. The internal pressure changes from high pressure at the inlet - low pressure at the throat section (the pressure drops to the critical pressure) - low pressure at the outlet (further reduced to below the critical pressure), where the expansion section is used to accelerate the sonic fluid to supersonic speed (the faster the flow rate, the lower the pressure), so the internal fluid velocity changes from subsonic - sonic - supersonic. Laval tubes are generally used to propel / accelerate fluids.

[0038] This application designs an atomization chamber structure including a LAVAL tube. The LAVAL tube connects the flow guide nozzle and the centrifugal turntable, and its throat section is arranged vertically and docked with the end outlet of the flow guide nozzle. This design has several key advantages: 1. By connecting to the air source, the LAVAL tube can form a stable air pressure environment in the throat section, effectively solving the problem of air pressure fluctuation in the recirculation area below the guide nozzle in the conventional combined atomization process.

[0039] 2. When the metal melt passes through the LAVAL throat section, it will be pre-broken by the high-speed airflow, which prepares for the subsequent centrifugal atomization.

[0040] 3. The special structure of the LAVAL pipe can discharge the pre-crushed molten metal downward without the need for additional pumping devices, thus avoiding the technical difficulties of high-temperature molten metal discharge.

[0041] 4. After the gas in the LAVAL tube pre-crushes the molten metal flowing out of the guide nozzle, the resulting gas-liquid mixture moves mainly by its own speed. The gas in the LAVAL tube will accelerate the crushing of the molten metal fragments, allowing them to gain speed, further improving the stability of the atomization process.

[0042] Through this design, the present application successfully integrates the LAVAL tube into the metal powder atomization equipment, achieving multiple functions of air pressure stabilization, melt pre-crushing and flow control. This innovative structural design not only solves the air pressure fluctuation problem in the original technology, but also optimizes the entire atomization process, which is expected to significantly improve the quality and production efficiency of metal powder.

[0043] The core innovation of this application is to introduce the LAVAL tube as a metal melt pre-crushing and pressure stabilizing device. By combining the LAVAL tube with the guide nozzle and the centrifugal turntable, a unique atomization system is formed. This design not only solves the problem of air pressure fluctuation in the recirculation zone below the guide nozzle in traditional atomization equipment, but also realizes the function of pre-crushing the metal melt and controlling the flow rate, thereby significantly improving the stability and efficiency of the atomization process.

[0044] The working principle of the metal powder atomization equipment of the present application is as follows: First, the smelting chamber melts the alloy masterbatch into liquid metal melt. The smelting chamber can be lined with refractory materials and equipped with a temperature control system to maintain an appropriate smelting temperature. After the smelting is completed, the liquid metal melt is introduced into the LAVAL tube through the guide nozzle. The guide nozzle is made of high-temperature resistant ceramic or graphite material, and its end outlet is precisely aligned with the throat section of the LAVAL tube to ensure that the metal melt can accurately enter the throat section.

[0045] The LAVAL tube is the core component of this equipment, including the inlet section, throat section and outlet section. The cross-sectional area of ​​the inlet section gradually decreases, the cross-sectional area of ​​the throat section is constant and the smallest, and the cross-sectional area of ​​the outlet section gradually increases. The LAVAL tube is connected through an external air source to form a stable air pressure environment in the throat section. When the molten metal enters the throat section, it is pre-crushed by high-speed airflow. This pre-crushing process not only homogenizes the molten metal, but also helps the subsequent atomization process.

[0046] The pre-crushed molten metal is discharged downwards under the special structure of the LAVAL tube. This discharge effect is produced by the geometric shape of the LAVAL tube and the airflow dynamics, without the need for additional mechanical pumping devices. This design cleverly solves the technical problem of high-temperature molten metal being difficult to discharge.

[0047] The centrifugal turntable is located directly below the LAVAL tube and is driven by a high-speed motor. When the pre-crushed molten metal is discharged from the LAVAL tube, it falls directly onto the high-speed rotating centrifugal turntable. Under the action of centrifugal force, the molten metal forms a uniform film on the surface of the turntable, and is further atomized into tiny metal droplets under the combined action of centrifugal force and surface tension.

[0048] Through this design, the present application successfully integrates the LAVAL tube into the metal powder atomization equipment, achieving multiple functions of air pressure stabilization, melt pre-crushing and flow control. The introduction of the LAVAL tube not only solves the problem of air pressure fluctuation in the reflow zone below the guide nozzle, but also optimizes the entire atomization process, which is expected to significantly improve the quality and production efficiency of metal powder.

[0049] In certain embodiments, referring to Figure 2The LAVAL tube 220 includes an outer shell 222 that encloses a flow channel. The outer shell 222 is a multi-layer structure that includes an inner layer, an insulation layer and a protective layer from the inside to the outside (the multi-layer structure is not shown); the inner layer is made of a high-temperature resistant and corrosion-resistant material; the insulation layer is made of an insulation material; and the protective layer is made of a protective material.

[0050] The LAVAL tube of the present application adopts a multi-layer structure design, which includes an inner layer, an insulation layer and a protective layer from the inside to the outside. The inner layer is made of a high temperature resistant and corrosion resistant material, which can directly contact the high temperature molten metal to prevent the LAVAL tube from being corroded and damaged. The insulation layer is made of an insulation material, which can reduce heat loss and maintain the temperature of the molten metal. The protective layer is made of a protective material, which can protect the internal structure from the influence of the external environment.

[0051] This multi-layer structure design can effectively solve the technical problems of LAVAL tubes in high temperature resistance, corrosion resistance and thermal insulation. The inner layer is resistant to high temperature and corrosion, and can work stably for a long time; the thermal insulation layer reduces heat loss and improves energy utilization efficiency; the protective layer increases the overall structural strength and extends the service life of the equipment. The three-layer structure cooperates with each other to ensure the stable operation of the LAVAL tube in high temperature and corrosive environments, and improves the working efficiency and product quality of metal powder atomization equipment.

[0052] Specifically, the LAVAL tube of the present application adopts a multi-layer structure design, which can achieve multiple protections and functional separation. The inner layer, as the part that directly contacts the high-temperature molten metal, can be made of high-temperature resistant and corrosion-resistant materials, such as ceramic materials (such as silicon nitride, silicon carbide, aluminum oxide, etc.), high-temperature alloys, or metal materials treated with special coatings. These materials have excellent high-temperature resistance and chemical stability, which can effectively prevent the metal melt from corroding and eroding the LAVAL tube, thereby extending the service life of the equipment.

[0053] The insulation layer is located between the inner layer and the protective layer. Materials with low thermal conductivity can be selected, such as ceramic fiber, aerogel or other high-efficiency insulation materials. The design of the insulation layer can significantly reduce the heat transfer from the inner layer to the outside, help maintain the temperature of the metal melt, and improve energy efficiency. In addition, the insulation layer can also act as a buffer, reduce the thermal stress between the inner and outer layers, and further improve the structural stability of the LAVAL pipe.

[0054] As the outermost layer, the protective layer can be made of materials with good mechanical properties and wear resistance, such as high-strength alloy steel (such as stainless steel) or composite materials. The protective layer can not only protect the internal structure from the influence of the external environment, but also increase the overall strength and rigidity of the LAVAL pipe, and improve the pressure resistance and impact resistance of the equipment.

[0055] The synergy between these three layers significantly improves the overall performance of the LAVAL pipe. The high temperature and corrosion resistance of the inner layer ensures the stable flow of the metal melt, the thermal insulation effect of the insulation layer maintains the melt temperature, and the protective layer enhances the stability of the overall structure. This multi-layer structure design not only solves the problem that a single material is difficult to meet the requirements of high temperature resistance, corrosion resistance and thermal insulation at the same time, but also achieves an overall improvement in the performance of the LAVAL pipe through the optimized combination of the functions of each layer.

[0056] The multi-layer LAVAL tube of the present application has significant advantages over the traditional single-layer LAVAL tube. Traditional single-layer LAVAL tubes usually use a single material, such as heat-resistant steel or high-temperature alloys, which is difficult to meet the requirements of high temperature resistance, corrosion resistance and thermal insulation at the same time. In high-temperature environments, single-layer structures are prone to problems such as material performance degradation, thermal stress concentration and heat loss, resulting in short equipment life and low energy efficiency. The multi-layer structure design of the present application effectively solves these problems through functional separation and material optimization, significantly improves the comprehensive performance and service life of the LAVAL tube, and provides reliable guarantees for the stable operation and product quality of metal powder atomization equipment.

[0057] In some embodiments, the inner layer may be provided with an induction or resistive heating device to maintain the temperature of the molten metal in the LAVAL tube.

[0058] In certain embodiments, referring to Figure 3 The flow channel includes an air chamber 223, an inlet section 224, a throat section 221 and an outlet section 225 which are connected in sequence. The cross-sectional area of ​​the air chamber 223 is constant and larger than the cross-sectional area of ​​the throat section 221. The air chamber 223 is used to connect to the air source; the cross-sectional area of ​​the inlet section 224 gradually decreases toward the throat section 221; the cross-sectional area of ​​the throat section 221 is constant; the cross-sectional area of ​​the outlet section 225 gradually increases toward the throat section 221, and the outlet section 225 is used to output the molten metal.

[0059] The flow channel design proposed in this application includes an air chamber, an inlet section, a throat section and an outlet section (also known as an expansion section) that are connected in sequence. This design can be implemented in a variety of ways to adapt to different application scenarios and requirements.

[0060] The design of the air chamber can be cylindrical, elliptical or polygonal, with a constant cross-sectional area greater than the cross-sectional area of ​​the throat. The air chamber can be connected to the gas source by flange, thread or welding to ensure a stable gas supply.

[0061] The inlet section can be designed in a linear or curved manner so that the cross-sectional area gradually decreases towards the throat section. This tapered design can be precisely implemented through advanced manufacturing technologies such as CNC machining or 3D printing to achieve optimal fluid dynamics performance.

[0062] The throat section is designed to keep the cross-sectional area constant and can adopt a circular cross-section. The length of the throat section can be adjusted according to the specific application requirements to ensure that the airflow reaches the speed of sound and forms a stable air pressure environment.

[0063] The outlet section is designed with a gradual expansion structure, and the cross-sectional area gradually increases in the direction away from the throat section. This design can adopt a linear expansion or a curved expansion method, and the output effect of the metal melt can be optimized by precisely controlling the expansion angle.

[0064] The relationship and interaction between these features form a complete flow system. The air chamber provides a stable air source, the inlet section accelerates the air flow, the throat section forms a stable air pressure environment, and the outlet section controls the output process of the molten metal. This design, combined with the overall structure of the LAVAL tube, forms an efficient molten metal delivery system.

[0065] In practical applications, the size ratio of each section can be adjusted according to the characteristics of the metal melt and the atomization requirements. For example, the diameter of the air chamber can be set to 1.5-2 times the diameter of the throat section, the contraction angle of the inlet section can be between 15°-30°, and the expansion angle of the outlet section can be between 5°-15°. These parameters can be determined by fluid dynamics simulation and experimental optimization to determine the optimal value.

[0066] The technical solution of the present application effectively solves the problem of molten metal flow fluctuations through a special flow channel design. The design of the air chamber cross-sectional area being larger than the throat section cross-sectional area ensures a stable gas supply. The tapered design of the inlet section accelerates the airflow and increases the kinetic energy of the airflow. The constant cross-sectional area design of the throat section forms a stable air pressure environment here to pre-crush the molten metal. The gradually expanding design of the outlet section controls the output process of the molten metal, increases the gas velocity to supersonic speed, and ensures that there is enough kinetic energy to output the molten metal.

[0067] The working principle of this design is based on the principle of gas dynamics. When the gas enters the inlet section from the gas chamber, the cross-sectional area decreases, the gas velocity increases, and the pressure energy is converted into kinetic energy. In the throat section, the gas reaches the speed of sound, forming a stable air pressure environment. The metal melt is pre-broken in this stable air pressure environment, while preventing the occurrence of backflow. In the outlet section, the gas reaches supersonic speed and outputs the metal melt.

[0068] Compared with traditional atomization equipment, the technical solution of this application has significant advantages. It avoids the risk of equipment damage that may be caused by using mechanical pumping methods, and at the same time, by accurately controlling the air pressure environment, it effectively solves the problem of unstable metal melt flow caused by air pressure fluctuations in the reflow zone. This design not only improves the atomization efficiency, but also improves the quality of metal powder, providing technical support for the production of high-quality metal powder.

[0069] Compared with the prior art, the technical solution of this application shows obvious advantages in the following aspects: First, traditional atomization equipment often relies on mechanical pumping or pressure flow to control the flow of molten metal. These methods are easily affected by external factors, resulting in unstable flow. This application uses a special flow channel design and gas dynamics principles to control the flow of molten metal, greatly improving the stability of the flow.

[0070] Secondly, the common backflow zone problem in the prior art has been effectively solved in the design of this application. By forming a stable air pressure environment in the throat section, the technical solution of this application effectively prevents the occurrence of backflow, thereby avoiding the flow fluctuation caused by it.

[0071] Thirdly, the design of the present application greatly reduces the risk of equipment damage compared to the traditional mechanical pumping method. The corrosion and wear of mechanical parts by high-temperature molten metal is a serious problem, and the pneumatic design of the present application avoids this problem and improves the reliability and life of the equipment.

[0072] Finally, the technical solution of the present application significantly improves the atomization efficiency and product quality by precisely controlling the pre-crushing and output process of the metal melt. This is not only reflected in the improvement of the powder particle size distribution, but also in the optimization of the powder morphology, such as the improvement of sphericity and the reduction of satellite powder.

[0073] In certain embodiments, referring to Figure 2 The flow channel includes an air chamber 223, an inlet section 224, a throat section 221, an outlet section 225 and a stabilizing section 226 which are connected in sequence. The cross-sectional area of ​​the air chamber 223 is constant and larger than the cross-sectional area of ​​the throat section 221, and the air chamber 223 is used to connect to the air source; the cross-sectional area of ​​the inlet section 224 gradually decreases toward the throat section 221; the cross-sectional area of ​​the throat section 221 is constant; the cross-sectional area of ​​the outlet section 225 gradually increases toward the throat section 221; the cross-sectional area of ​​the stabilizing section 226 is constant, and the stabilizing section 226 is used to output the molten metal.

[0074] Compared with the above-mentioned embodiment, the present embodiment adds a stabilizing section, which is an improvement on the traditional LAVAL tube structure. The cross-sectional area of ​​the stabilizing section is constant, and is used to output the molten metal. The design of the stabilizing section can further stabilize the flow of the molten metal and reduce flow fluctuations. This ensures that the molten metal is smoothly output to the centrifugal turntable. Through this design, the metal powder atomization equipment of the present application can effectively reduce the fluctuation of the molten metal flow rate. In practical applications, this design can effectively control the flow fluctuation of the molten metal, which is significantly lower than the fluctuation range of traditional equipment. This stable supply of molten metal can significantly improve the effect of centrifugal atomization, so that the particle size distribution of the produced metal powder is more uniform and the sphericity is higher.

[0075] In certain embodiments, referring to Figure 3 , the relationship between the outlet inner diameter of the outlet section and the diameter of the centrifugal turntable satisfies: ; in, is the outlet inner diameter of the outlet section, The height distance between the LAVAL tube and the centrifugal turntable (usually between 10-200mm). is the expansion angle of the outlet section (usually between 4°-12°), is the diameter of the centrifugal turntable, is a preset constant less than 1.

[0076] The present application establishes a mathematical relationship between the outlet inner diameter of the LAVAL tube outlet section, the height spacing between the LAVAL tube and the centrifugal turntable, the expansion angle of the outlet section, and the centrifugal turntable diameter, so as to achieve efficient reception of the molten metal output by the LAVAL tube by the centrifugal turntable. Specifically, by controlling the relationship between these parameters, the molten metal flowing out of the LAVAL tube outlet can accurately fall on the centrifugal turntable, avoiding scattering and instability of the molten metal during flight in the air. This design ensures that the molten metal can be evenly distributed on the centrifugal turntable, thereby improving the stability and efficiency of the atomization process, and ultimately helping to improve the quality and output of metal powder.

[0077] The design of this relationship takes into account the interaction of multiple factors: The outlet inner diameter of the outlet section directly affects the outflow speed and flow rate of the molten metal. A larger outlet inner diameter may cause the molten metal to disperse more widely.

[0078] The height gap between the LAVAL tube and the centrifugal turntable affects the time and distance of the metal melt falling from the LAVAL tube to the centrifugal turntable. A larger gap may cause the metal melt to fly in the air for a longer time, increase instability, and reduce the temperature of the metal melt.

[0079] The divergence angle of the outlet section affects the diffusion range of the molten metal after leaving the LAVAL tube. A larger divergence angle may cause the molten metal to disperse more widely.

[0080] The diameter of the centrifugal turntable determines the area for receiving the molten metal. A larger diameter can receive the molten metal more efficiently, but it may increase the difficulty of speed control of the high-speed motor.

[0081] By adjusting these parameters, the following effects can be achieved: Ensure that the molten metal can flow stably from the LAVAL tube to the centrifugal turntable, reducing instability during flight in the air.

[0082] Control the distribution range of the metal melt on the centrifugal turntable to prevent the metal melt from overflowing the edge of the turntable or concentrating in the center of the turntable.

[0083] Ensure that the metal melt has a suitable temperature and improve the atomization efficiency.

[0084] By setting the preset constants appropriately , the best parameter combination can be found under different atomization conditions to adapt to different types of metal melts and atomization requirements.

[0085] By establishing this mathematical relationship, the technical solution of the present application not only enables the centrifugal turntable to efficiently receive the metal melt output by the LAVAL tube, but also provides an adjustable and optimizable design method. This method can achieve the best atomization effect by adjusting relevant parameters according to different metal materials, atomization requirements and equipment conditions.

[0086] Compared with the prior art, the technical solution of this application has the following advantages: A quantifiable design is provided, making the design of metal powder atomization equipment more precise and controllable.

[0087] By optimizing the parameter relationship between the LAVAL tube outlet and the centrifugal turntable, the movement stability of the metal melt is significantly improved and the unstable factors in the atomization process are reduced.

[0088] This design method has strong adaptability and can adjust parameters according to different metal materials and atomization requirements, thus improving the versatility and flexibility of the equipment.

[0089] By improving the movement state of the metal melt, the technical solution of the present application helps to improve the quality of the metal powder, such as narrower particle size distribution, higher sphericity, and less satellite powder and hollow powder.

[0090] In general, this application establishes a mathematical relationship between the key parameters of the LAVAL tube outlet and the centrifugal turntable to achieve efficient reception of the metal melt output by the LAVAL tube by the centrifugal turntable. This method not only improves the stability and efficiency of the atomization process, but also provides new ideas for the design and optimization of metal powder atomization equipment, which helps to improve the quality and output of metal powder and meet the demand for high-quality metal powder in fields such as metal additive manufacturing.

[0091] In some embodiments, the centrifugal turntable 230, the rotary driver 240 and the support base 250 form a centrifugal atomizer. The rotary driver can be a motor or the like.

[0092] In certain embodiments, referring to Figure 4 , the relationship between the outlet inner diameter of the stable section and the diameter of the centrifugal turntable satisfies: ; in, is the outlet inner diameter of the stable section, is the diameter of the centrifugal turntable, is a preset constant less than 1.

[0093] In this embodiment, the high-speed gas-liquid mixed jet ejected from the LAVAL tube outlet directly impacts the centrifugal turntable, thereby forming an extremely thin and uniform metal melt film. The metal melt film can only be atomized after being accelerated by the centrifugal turntable. If the metal melt film is accelerated from the centrifugal turntable, then the metal melt film needs to be accelerated along the radial direction of the centrifugal turntable for a certain distance, that is, the high-speed gas-liquid mixed jet ejected from the LAVAL tube cannot completely cover the entire centrifugal turntable surface, but is on the centrifugal turntable with a diameter of is a circle with a radius of The diameter required for efficient atomization varies with the type of atomized alloy. will also be different, that is, the constant in the formula It will also vary with the type of atomized alloy. It can be judged through atomization experiment or experience.

[0094] This design plays an important role in solving the problem of the relationship between the inner diameter of the outlet of the LAVAL tube stabilization section and the diameter of the centrifugal turntable. By limiting the proportional relationship between the inner diameter of the outlet of the stabilization section and the diameter of the centrifugal turntable, it can be ensured that the molten metal output from the stabilization section can be evenly distributed on the centrifugal turntable. This design helps to control the diffusion range of the molten metal after it flows out of the stabilization section, so that it can better fall on the centrifugal turntable, thereby improving the atomization efficiency and powder quality.

[0095] Specifically, when the ratio of the outlet inner diameter of the stable section to the centrifugal turntable diameter is not greater than a preset constant, the following technical effects can be achieved: 1. Optimize the distribution of molten metal on the centrifugal turntable: By controlling the ratio of the inner diameter of the stable section outlet to the diameter of the centrifugal turntable, it can be ensured that the molten metal flow can be effectively received by the centrifugal turntable to avoid the melt overflowing or concentrating in the center of the turntable.

[0096] 2. Improve atomization efficiency: A reasonable ratio can make the metal melt form a uniform liquid film on the centrifugal turntable, which is beneficial to the subsequent centrifugal atomization process and improves the yield and quality of the powder.

[0097] 3. Improve the powder particle characteristics: By optimizing the distribution of the metal melt on the centrifugal turntable, a more uniform distribution of powder particle size can be obtained, the sphericity of the powder can be improved, and the generation of satellite powder and hollow powder can be reduced.

[0098] 4. Enhance process stability: Reasonable size ratio can reduce the turbulence and instability of the metal melt on the centrifugal turntable, which helps to maintain the stability of the atomization process.

[0099] Compared with the prior art, the present application provides clear parameter guidance for equipment design by establishing a mathematical relationship between the inner diameter of the stable section outlet and the diameter of the centrifugal turntable. This quantitative design method helps to optimize the equipment structure and improve the stability and controllability of the atomization process. Traditional design methods often rely on experience and repeated experiments, and it is difficult to quickly find the optimal structural parameters. The technical solution of the present application makes the equipment design more scientific and efficient through simple mathematical relationships, which can significantly reduce the design and debugging time and improve the performance and reliability of the equipment.

[0100] In certain embodiments, referring to Figure 5 , the size of the throat section satisfies: ; in, is the outer diameter of the guide nozzle, is the inner diameter of the throat section.

[0101] The present application realizes a reasonable ratio between the guide nozzle and the throat section size. This ratio relationship can ensure that the metal melt is fully pre-broken in the throat section. If the ratio is too small, the molten metal column output by the guide nozzle may not be able to fully contact the high-speed airflow, affecting the pre-crushing effect. When the ratio is too large, the airflow in the throat section may be obstructed too much, affecting the airflow speed and stability.

[0102] Suitable The ratio helps to form a stable air pressure environment in the throat section. This stable air pressure can reduce the pressure fluctuation in the reflow zone below the guide nozzle, thereby effectively controlling the flow fluctuation of the metal melt and improving the stability of the atomization process. By optimizing the size relationship between the guide nozzle and the throat section, the movement state of the metal melt in the throat section can be improved, the contact between the melt and the throat section wall can be reduced, and the risk of melt cooling and adhesion can be reduced.

[0103] Reasonable The ratio can reduce the resistance of the guide nozzle end to the airflow while ensuring the pre-crushing effect, thereby improving energy efficiency. This size ratio design not only takes into account the principles of fluid mechanics, but also takes into account the process requirements in actual production. Compared with the existing technology, this size ratio optimization can significantly improve the atomization effect without increasing the complexity of the equipment.

[0104] In addition, this ratio can be fine-tuned according to the specific atomization process and metal material properties. For example, for metal melts with lower viscosity, the ratio can be appropriately increased. ratio to ensure sufficient melt flow; for easily oxidized metal materials, the ratio can be slightly reduced ratio to increase the air flow velocity and shorten the time the melt is exposed to the air.

[0105] Through this size ratio design, the present application effectively solves the size ratio problem of the guide nozzle and the throat section in the metal powder atomization equipment, improves the stability and efficiency of the atomization process, and is conducive to the production of higher quality metal powder. Compared with the prior art, the design of the present application not only optimizes the atomization effect, but also improves the energy utilization efficiency of the equipment, reduces the cooling and adhesion problems of the metal melt in the throat section, thereby improving the product quality and production efficiency of the metal powder.

[0106] In certain embodiments, the air pressure in the throat section satisfies: ; in, is the air pressure in the throat, is the air pressure at the inlet section, is the gas adiabatic coefficient.

[0107] In this embodiment, once the air pressure at the inlet section Determined (i.e. the air supply pressure of the LAVAL pipe is determined), the pressure P1 of the throat section of the LAVAL pipe is also determined. Conversely, the pressure required by the throat section of the LAVAL pipe can also be determined. To determine the supply pressure of the LAVAL pipe Due to the pressure in the throat section of the LAVAL pipe That is, the air pressure at the outlet of the nozzle. Therefore, the throat section of the LAVAL tube effectively improves the stability of the air pressure at the outlet of the nozzle, and then improves the stability of the pressure difference between the gas pressure on the surface of the molten metal in the tundish and the gas pressure at the end of the nozzle, thereby improving the stability of the flow rate of the molten metal flowing out of the nozzle. At the same time, the sonic or supersonic airflow formed by the LAVAL tube only needs to pre-crush and disperse the molten metal at the outlet of the nozzle. The air supply pressure of the LAVAL tube is The gas supply pressure of the LAVAL tube does not need to be as high as that of the conventional atomization process. When the LAVAL pipe uses the exhaust gas of the dust collector as the air intake source, the lower The performance requirements for the return fan will also be reduced.

[0108] Compared with the prior art, traditional atomization equipment usually uses a simple pressure regulating valve to control the air pressure, which is difficult to achieve precise control and prone to air pressure fluctuations. However, this application achieves precise control of the throat section air pressure by establishing a clear mathematical relationship and combining the thermodynamic characteristics of the gas. This method not only improves the stability of the atomization process, but also provides a theoretical basis for the optimization of atomization parameters under different materials and process conditions, and effectively solves the problems of air pressure fluctuations in the reflow zone and unstable metal melt flow in the prior art.

[0109] In certain embodiments, referring to Figure 1 The metal powder atomization equipment also includes a cyclone separator 300, a dust collector 400, a return fan 500 and a heater 600 which are connected in sequence. The cyclone separator 300 is connected to the atomization chamber 200 and is used to separate particles in the gas output by the atomization chamber 200; the dust collector 400 is used to separate particles in the gas output by the cyclone separator 300; the return fan 500 is used to pressurize the gas output by the dust collector 400; the heater 600 is used to heat the gas output by the return fan 500, and the heater 600 is connected to the LAVAL pipe 220 so that the pressurized and heated gas is connected to the LAVAL pipe 220 as a gas source.

[0110] This application solves the problem of gas recycling and energy efficiency in metal powder atomization equipment by introducing a gas circulation system. The cyclone separator and dust collector ensure the cleanliness of the circulating gas, the return fan provides the power required for gas circulation, and the heater (which can be a serpentine elbow heat exchanger or a plate-fin heat exchanger) ensures the appropriate temperature of the circulating gas. This closed-loop design not only reduces gas consumption, but also improves energy efficiency by reusing the heated gas. At the same time, the heated gas is used as the gas source of the LAVAL tube to ensure the stability and efficiency of the atomization process.

[0111] Specifically, the cyclone separator is connected to the atomization chamber and is used to separate large particles in the gas generated during the atomization process and preliminarily purify the gas. The cyclone separator can be designed in multiple stages to further improve the separation efficiency. For example, a two-stage or three-stage cyclone separator can be set, and each stage of the cyclone separator can separate particles of different particle size ranges.

[0112] The dust collector further separates the fine particles in the gas output by the cyclone separator to ensure the cleanliness of the circulating gas. Dust collectors can be of various types, such as bag filters or electrostatic precipitators. The selection of the appropriate type of dust collector can be based on the characteristics of the metal powder and production requirements. For example, for finer metal powders, a high-efficiency electrostatic precipitator can be selected.

[0113] The return fan pressurizes the purified gas and provides power for the gas to re-enter the LAVAL tube. The selection of the return fan needs to consider the pressure loss of the system and the required gas flow. A frequency conversion controlled return fan can be used to adjust the gas flow and pressure according to actual production needs.

[0114] The heater heats the pressurized gas to the appropriate temperature to ensure that the gas re-entering the LAVAL tube has the appropriate temperature and pressure. The heater can be heated by electricity or gas, and the specific choice can be determined based on energy costs and production scale. The temperature control system of the heater can be linked with the temperature monitoring system of the LAVAL tube to achieve precise temperature control.

[0115] These components cooperate with each other to achieve gas recycling and reduce gas consumption. At the same time, by heating the circulating gas instead of the fresh gas, the energy utilization efficiency is improved. Therefore, the technical solution of the present application not only solves the problem of gas recycling, but also improves the overall energy efficiency through the closed-loop system.

[0116] Compared with the prior art, traditional metal powder atomization equipment usually adopts an open system, and the gas is directly discharged after use, causing resource waste and environmental pollution. However, the present application not only solves the problem of resource waste by introducing a closed-loop gas circulation system, but also improves energy efficiency by reusing the heated gas. In addition, the system of the present application ensures the stability and efficiency of the atomization process by precisely controlling the cleanliness, pressure and temperature of the circulating gas, which is difficult to achieve with a traditional open system.

[0117] It should be noted that if the gas filtered by the dust collector meets the oxygen content requirements, part of the gas will enter the LAVAL pipe through the return fan, and the other part of the gas will be discharged through the induced draft fan.

[0118] In certain embodiments, referring to Figure 6 The flow guide nozzle 210 is integrated with the housing 222 as a bypass of the flow channel.

[0119] The technical solution proposed in this application solves the structural problem of connecting the flow guide nozzle to the LAVAL tube by integrating the flow guide nozzle as a bypass of the flow channel with the shell. This design simplifies the overall structure of the device, improves the integration of the device, reduces the number of connecting parts, reduces the risk of leakage, and ensures the precise alignment between the flow guide nozzle and the LAVAL tube.

[0120] Specifically, the design of the guide nozzle as a bypass of the flow channel and the shell as one can be realized in a variety of ways. For example, the guide nozzle can be designed and manufactured directly as a part of the shell by an integrated molding method. Another way is to firmly connect the guide nozzle to the shell by welding or high-strength adhesive to form an integrated structure. This integrated design not only solves the sealing and alignment problems that may occur in traditional separate connections, but also improves the safety and reliability of the equipment.

[0121] Furthermore, the design of using the guide nozzle as a bypass of the flow channel can ensure that the metal melt will not excessively interfere with the main airflow when entering the LAVAL tube. This design is conducive to maintaining a stable air pressure and flow field in the LAVAL tube, thereby ensuring that the pre-crushing effect of the metal melt and the subsequent atomization process are more efficient and uniform. Therefore, the technical solution of the present application not only solves the structural problem, but also indirectly improves the atomization effect.

[0122] In addition, this integrated design simplifies the assembly and maintenance process of the equipment. Since the number of parts that need to be disassembled and reinstalled is reduced, the service life and maintenance efficiency of the equipment are improved. For example, when performing routine maintenance, technicians can more easily clean and inspect the entire flow channel without worrying about errors or damage that may be introduced during the disassembly and reinstallation process.

[0123] As a preferred embodiment, the guide nozzle can be made of the same material as the LAVAL tube shell to ensure the consistency of the thermal expansion coefficient and avoid stress concentration or deformation caused by temperature changes.

[0124] In practical applications, the integrated design of the guide nozzle and the housing can be optimized according to specific atomization requirements. For example, the angle and position of the guide nozzle can be adjusted to ensure that the molten metal enters the throat section of the LAVAL tube in the best state. By precisely controlling the outlet diameter and position of the guide nozzle, the pre-crushing effect of the molten metal can be further optimized, thereby improving the quality and uniformity of the final atomized product.

[0125] Compared with the prior art, the integrated design of the present application significantly simplifies the equipment structure and reduces potential leakage points and sources of failure. Traditional separate designs usually require the use of sealing rings or gaskets to ensure the sealing of the joints, which not only increases the difficulty of assembly, but may also cause sealing failure due to long-term use. In contrast, the integrated design of the present application fundamentally eliminates these problems and improves the overall reliability and service life of the equipment.

[0126] In addition, the design of the present application also optimizes the flow path of the molten metal. By using the guide nozzle as a bypass design of the flow channel, the molten metal is prevented from directly impacting the main airflow of the LAVAL tube. This design not only improves the atomization efficiency, but also helps to produce more uniform metal powder particles.

[0127] In general, this application effectively solves the structural problem of connecting the guide nozzle and the LAVAL tube through the integrated design of the guide nozzle and the shell, while improving the overall performance and reliability of the equipment. This innovative design provides new ideas and directions for the further optimization and development of metal powder atomization equipment.

[0128] In some embodiments, the heating device disposed on the housing 222 can also heat the guide nozzle 210 serving as a bypass, thereby maintaining the temperature of the molten metal in the guide nozzle 210 .

[0129] In certain embodiments, referring to Figure 6 The inlet section 224 is a curved pipe structure, and the length of the throat section 221 is at least twice the diameter of the inlet section 224. The terminal outlet of the guide nozzle 210 is located at the middle and lower part of the length of the throat section 221 along the flow direction.

[0130] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0131] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A metal powder atomization device, characterized in that: include: A smelting chamber (100), wherein the smelting chamber (100) is used to smelt the alloy mother material into a liquid metal melt; An atomization chamber (200), the atomization chamber (200) comprising a guide nozzle (210), a LAVAL tube (220) and a centrifugal turntable (230), the guide nozzle (210) being connected to the smelting chamber (100) and the LAVAL tube (220), the end outlet of the guide nozzle (210) being located at a throat section (221) of the LAVAL tube (220), and the throat section (221) being arranged vertically relative to a horizontal plane, the guide nozzle (210) being used to guide the molten metal to the throat section (221). 21); the LAVAL tube (220) is used to form a stable air pressure in the throat section (221) by connecting to an air source, and to pre-crush the molten metal flowing out of the guide nozzle (210), and to output the molten metal in the throat section (221) downward after the pre-crushing; the centrifugal turntable (230) is located directly below the LAVAL tube (220), and the centrifugal turntable (230) is used to receive the molten metal output from the LAVAL tube (220) and to atomize the molten metal.

2. The metal powder atomization equipment according to claim 1, characterized in that: The LAVAL tube (220) comprises an outer shell (222) that encloses a flow channel. The outer shell (222) is a multi-layer structure that includes an inner layer, a thermal insulation layer, and a protective layer from the inside to the outside. The inner layer is made of a high temperature resistant and corrosion resistant material. The thermal insulation layer is made of a thermal insulation material. The protective layer is made of a protective material.

3. The metal powder atomization equipment according to claim 2, characterized in that: The flow channel comprises an air chamber (223), an inlet section (224), the throat section (221) and an outlet section (225) which are connected in sequence; the cross-sectional area of ​​the air chamber (223) is constant and greater than the cross-sectional area of ​​the throat section (221); the air chamber (223) is used to connect to an air source; the cross-sectional area of ​​the inlet section (224) gradually decreases in a direction approaching the throat section (221); the cross-sectional area of ​​the throat section (221) is constant; the cross-sectional area of ​​the outlet section (225) gradually increases in a direction away from the throat section (221); the outlet section (225) is used to output the molten metal.

4. The metal powder atomization equipment according to claim 2, characterized in that: The flow channel comprises an air chamber (223), an inlet section (224), the throat section (221), an outlet section (225) and a stabilizing section (226) which are connected in sequence; the cross-sectional area of ​​the air chamber (223) is constant and greater than the cross-sectional area of ​​the throat section (221); the air chamber (223) is used to connect to an air source; the cross-sectional area of ​​the inlet section (224) gradually decreases in a direction approaching the throat section (221); the cross-sectional area of ​​the throat section (221) is constant; the cross-sectional area of ​​the outlet section (225) gradually increases in a direction away from the throat section (221); the cross-sectional area of ​​the stabilizing section (226) is constant; the stabilizing section (226) is used to output the molten metal.

5. The metal powder atomization equipment according to claim 3, characterized in that: The relationship between the outlet inner diameter of the outlet section and the diameter of the centrifugal turntable satisfies: ； in, is the outlet inner diameter of the outlet section, is the height distance between the LAVAL tube and the centrifugal turntable, is the expansion angle of the outlet section, is the diameter of the centrifugal turntable, is a preset constant less than 1.

6. The metal powder atomization equipment according to claim 4, characterized in that: The relationship between the outlet inner diameter of the stabilizing section and the diameter of the centrifugal turntable satisfies: ； in, is the outlet inner diameter of the stabilizing section, is the diameter of the centrifugal turntable, is a preset constant less than 1.

7. The metal powder atomization equipment according to claim 5 or 6, characterized in that: The dimensions of the throat section satisfy: ； in, is the outer diameter of the guide nozzle, is the inner diameter of the throat section.

8. The metal powder atomization equipment according to claim 7, characterized in that: The air pressure of the throat section satisfies: ； in, is the air pressure in the throat section, is the air pressure at the inlet section, is the gas adiabatic coefficient.

9. The metal powder atomization equipment according to claim 1, characterized in that: The invention also comprises a cyclone separator (300), a dust collector (400), a return air fan (500) and a heater (600) which are connected in sequence, wherein the cyclone separator (300) is communicated with the atomization chamber (200) and is used to separate particles in the gas output by the atomization chamber (200); the dust collector (400) is used to separate particles in the gas output by the cyclone separator (300); the return air fan (500) is used to pressurize the gas output by the dust collector (400); the heater (600) is used to heat the gas output by the return air fan (500), and the heater (600) is communicated with the LAVAL pipe (220) so that the pressurized and heated gas is connected to the LAVAL pipe (220) as a gas source.

10. The metal powder atomization equipment according to claim 3 or 4, characterized in that: The flow guide nozzle (210) serves as a bypass of the flow channel and is integrated with the housing (222).

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