A gas atomization device and method based on a crucible-type continuous self-circulation

Abstract

The application provides a kind of based on crucible type continuous self-circulation gas atomization device and method.The device includes smelting chamber, atomization chamber, first charging bin, first plug valve, first vacuum pump, first inert gas pipeline, first classifier, second classifier, cyclone separator, dust cloth bag, tail exhaust fan, first transfer tank, powder collecting tank, feeding fan, second transfer tank, rod making smelting furnace, second charging bin, second vacuum pump, second inert gas pipeline, conveyor belt, blank former and manipulator, etc.The method includes powder making through smelting chamber and atomization chamber, coarse powder is sent to rod making smelting furnace to obtain blank, blank is added into smelting chamber through first charging bin, coarse powder self-circulation and continuous smelting and atomization are realized.The device and method of the application realize continuous production and coarse powder self-circulation of VIGA, reduce the waste of manpower and material resources, and can promote the industrialization process of VIGA technology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vacuum gas atomization preparation of metal powder, in particular to the field of vacuum induction melting gas atomization powder preparation technology, and specifically relates to a gas atomization device and method based on a crucible type continuous self-circulation. BACKGROUND

[0002] In recent years, with the rapid development of science and technology, additive manufacturing technology is increasingly applied in the fields of aerospace, medical manufacturing, and civil mold, thereby forming a complementary situation with traditional machining (subtractive manufacturing) and casting (equivalent material manufacturing), and contributing their own strength to the manufacturing industry. Among them, metal additive manufacturing (commonly known as metal 3D printing) technology is praised as the king of additive technology because it mainly studies the preparation and performance optimization of metal powder raw materials, laser sintering pool of metal printing parts, and other cutting-edge technologies such as strength and stiffness performance. At present, research institutes such as Ningbo 52, the Iron and Steel Research Institute, and the Shanghai Institute of Materials have done a lot of research on metal raw material powder, forming a full life cycle system document of raw material preparation and process optimization, printing part post-processing and detection. However, in the metal 3D printing industry, especially in the research and development of materials and printing equipment, researchers still need to continue to explore.

[0003] As the raw material of metal 3D printing, metal powder plays a crucial role in the final performance of the printed part, and has high requirements for its powder parameters: high purity of chemical composition, certain particle size distribution, high powder sphericity, good flowability, and certain requirements for bulk density. Compared with mechanical ball milling and electrochemical methods, vacuum induction melting gas atomization technology (VIGA) has become the mainstream method for producing high-performance spherical metal powder due to its high production efficiency, high powder sphericity, and low oxygen content. Generally, VIGA technology uses a crucible melting method, that is, metal is added to the crucible, and the metal is melted into liquid steel by induction heating with medium frequency electricity. Then the liquid steel is poured into a tundish, and a certain diameter of liquid steel is discharged through the lower guide nozzle. The metal powder, commonly known as "through powder", can be obtained by atomizing and cooling the liquid steel with high-pressure inert gas. After screening and grading, 15-53 μm metal powder for 3D printing can be obtained, and 53-150 μm by-products are also produced.

[0004] Currently, the VIGA production mode is as follows: after gas atomization, "through powder" is obtained, and after screening and grading, metal powder of 15-53 mu for 3D printing is obtained. Due to the bottleneck of gas atomization technology research, the proportion of the obtained 15-53 mu finished powder to the raw material is 30%-35%, and 40%-55% of the powder is 53-150 mu of by-product coarse powder. The powder in this particle size range currently has no clear application field. The traditional method is to manually lift a certain weight of coarse powder to the equipment platform again, add it to the crucible, and form the raw material with the bar according to a certain proportion. After vacuumizing in a single furnace cycle, the bar itself generates eddy current heating under the action of medium frequency electricity to form a preliminary molten pool, and gradually melt the coarse powder into liquid steel, and finally perform atomization operation. After atomization is completed, after the crucible cools down, the raw material is added again, and then vacuumizing and inert gas backfilling are performed, and the atomization operation is repeated. The VIGA operation of this mode has the following problems: (1) the traditional single furnace cycle production mode needs to wait for the crucible to cool down after the atomization of a furnace, and then add the material, vacuumize, backfill argon and heat, which is a non-continuous production mode, which not only leads to low efficiency, but also greatly reduces the service life of the crucible due to repeated thermal shock and rapid cooling of the crucible. The service life of the traditional crucible is 20-25 furnace cycles; (2) when using coarse powder as the return material for production, impurities such as oxygen and nitrogen are easily brought in. Engineering practice shows that the return frequency of coarse powder should not exceed 3-4 times. If the return frequency is too high, impurities will accumulate, which will affect the final performance of the printed part, especially the high-temperature performance of the high-temperature alloy printed part used in the aerospace field, which will cause the high-temperature duration to decrease exponentially; (3) the traditional VIGA production must use a small amount of bar material, and cannot be all powder material, because the gap between the powder materials is too large, and the vortex cannot be formed under the action of medium frequency electricity, so the bar material needs to be used as "ignition material"; (4) the coarse powder after screening is generally placed in a collection bucket. When it needs to be returned, it is usually lifted to the melting chamber by a crane, and manually poured into the crucible. Not only is it time-consuming and labor-intensive, but also causes dust to stir and form a safety hazard.

[0005] Therefore, how to realize continuous production in industrialized VIGA production to improve efficiency, and use coarse powder for return, reduce the proportion of bar material, that is, realize the continuous and coarse powder self-circulation of VIGA, has become a key problem to be solved. SUMMARY

[0006] To solve the above technical problems, the purpose of the present application is to provide a gas atomization device and method based on crucible type continuous self-circulation. The gas atomization device and method based on crucible type continuous self-circulation provided by the present application can realize the continuous and coarse powder self-circulation of VIGA.

[0007] In order to achieve the above-mentioned purpose, the application provides a continuous self-circulation gas atomization device based on a crucible, which comprises a smelting chamber, an atomization chamber, a first feeding bin, a first plug valve, a first vacuum pump, a first inert gas pipeline, a first classifier, a second classifier, a cyclone separator, a dust cloth bag, a tail exhaust fan, a first transfer tank, a powder collecting tank, a feeding fan, a second transfer tank, a rod making smelting furnace, a second feeding bin, a second vacuum pump, a second inert gas pipeline, a conveyor belt, a blank former and a mechanical hand.

[0008] The smelting chamber is arranged above the atomization chamber, and the lower end of the smelting chamber is communicated with the atomization chamber.

[0009] The first feeding bin is arranged above the smelting chamber, and the lower end of the first feeding bin is provided with a first plug valve for realizing the communication and separation between the smelting chamber and the first feeding bin.

[0010] The side walls of the first feeding bin and the atomization chamber are connected to the first vacuum pump through pipelines.

[0011] The lower end of the atomization chamber is communicated with the first classifier, the first classifier is communicated with the second classifier, the second classifier is communicated with the cyclone separator, the cyclone separator is communicated with the dust cloth bag, the dust cloth bag is connected with the tail exhaust fan, the lower end of the first classifier is connected with the first transfer tank, and the lower ends of the second classifier, the cyclone separator and the dust cloth bag are respectively connected with the powder collecting tank.

[0012] The lower end of the first transfer tank is communicated with the upper end of the second transfer tank through the feeding fan.

[0013] The lower end of the second transfer tank is communicated with the rod making smelting furnace, the second feeding bin is arranged above the rod making smelting furnace, and the lower end of the second feeding bin is communicated with the rod making smelting furnace.

[0014] The side wall of the rod making smelting furnace is provided with a second inert gas pipeline, and the side wall of the rod making smelting furnace is connected to the second vacuum pump through a pipeline.

[0015] The lower end of the rod making smelting furnace is communicated with the blank former, the blank former is arranged above the conveyor belt, the conveyor belt is used for transporting the blank former to the first feeding bin, and the mechanical hand is used for loading blanks in the blank former into the first feeding bin.

[0016] In the above-mentioned gas atomization device, preferably, a first smelting crucible and a first tundish system are arranged in the smelting chamber, and the lower end of the smelting chamber is communicated with the atomization chamber through the first tundish system. More preferably, the lower end of the first tundish system is provided with a spray disc, and a flow guide nozzle is arranged on the spray disc, and the diameter of the flow guide nozzle is 3-6 mm. The first smelting crucible is used to smelt the metal raw material in the smelting chamber into liquid, and the spray disc arranged at the lower end of the first tundish system is used to spray the metal melt into the atomization chamber.

[0017] In the above-mentioned gas atomization device, preferably, the upper end of the first feeding bin is provided with a first motor and a first worm gear, and the inside of the first feeding bin is provided with a first roller, a barrel and a stop pin; the first motor is connected to the first roller through the first worm gear, a silk thread is wound on the first roller, the lower end of the silk thread is hung with the barrel, and the lower part of the inner wall of the first feeding bin is provided with a stop pin. More preferably, a roller is arranged on the stop pin.

[0018] In the above-mentioned gas atomization device, preferably, the barrel is of hollow structure, and the bottom of the barrel is uniformly provided with 4-8 support plates as bottom plates, the outer wall of the barrel is provided with lifting lugs, the lower edge of the barrel is fixedly connected with a bearing, the middle section of the support plate is connected with the bearing fixedly connected to the lower edge of the barrel, the outer side of the support plate and the lifting lugs of the outer wall of the barrel are connected through springs, and the support plate is used to realize the opening and closing of the lower end of the barrel. More preferably, the opening and closing angle of the support plate is 0-90°.

[0019] In the present application, the first feeding bin is arranged above the smelting chamber, and the lower end of the first feeding bin is provided with a first plug valve for realizing the communication and separation between the smelting chamber and the first feeding bin. The first feeding bin can be vacuumized through the first vacuum pump and then backfilled with inert gas through the first inert gas backfilling pipeline, so as to separate the operation of the first feeding bin from the smelting chamber. In addition, the upper end of the first feeding bin is provided with a first motor, power is transmitted to a first roller through a first worm gear, a silk thread is wound on the first roller, and the lower end of the silk thread is hung with a barrel. When the barrel is not loaded, the spring is in a state of sharp compression, and the inner side of the support plate remains in a closed state under the action of the lever force. Gradually increasing the material in the barrel, the support plate still remains in a closed state. The first motor drives the barrel to move downward, and when the barrel reaches a certain position, the outer side of the support plate at the bottom of the barrel contacts with the roller on the stop pin. Under the action of gravity, the barrel continues to move downward, and the 4-8 evenly distributed support plates are gradually opened. After the material falls into the smelting crucible of the smelting chamber, the first motor is started to drive the barrel to rise, and under the driving of the spring compression force, the support plate returns to the closed state, and the next feeding can be carried out. The design of the first feeding bin of the present application realizes the automatic feeding of the smelting crucible without contacting the high-temperature smelting crucible.

[0020] In the above-mentioned gas atomization device, preferably, a first pneumatic valve is arranged on the side wall of the atomization chamber and the pipeline connected with the first vacuum pump.

[0021] In the above-mentioned gas atomization device, preferably, a second pneumatic valve is arranged on the side wall of the first charging bin and the pipeline connected with the first vacuum pump.

[0022] In the above-mentioned gas atomization device, preferably, the frequency of the classification wheel of the first classifier is 10-30 Hz.

[0023] In the above-mentioned gas atomization device, preferably, the frequency of the feeding fan is 30-80 Hz, and the air volume is 20-120 Pa.

[0024] In the above-mentioned gas atomization device, preferably, the frequency of the classification wheel of the second classifier is 50-80 Hz.

[0025] In the above-mentioned gas atomization device, preferably, an exhaust valve is arranged on the pipeline connected with the cyclone separator and the dust removal bag.

[0026] In the present application, the rear section of the atomization chamber is provided with a double classification wheel structure, which can accurately control the particle size distribution of the obtained metal powder. The frequency of the classification wheel of the first classifier is 10-30 Hz, and the coarse powder with a particle size of 53-150 μm is obtained in the first transfer tank. The coarse powder is transported to the second transfer tank through the feeding fan, the frequency of the feeding fan is 30-80 Hz, and the air volume is 20-120 Pa. The frequency of the classification wheel of the second classifier is 50-80 Hz, and the metal powder product for 3D printing with a particle size of 15-53 μm can be obtained in the powder collecting tank connected with the lower end of the second classifier. The metal powder with a particle size of 0-15 μm obtained after classification in the second classifier is collected in the powder collecting tank connected with the lower end of the cyclone separator after gas-solid (i.e. gas and metal powder) separation by the cyclone separator. A small amount of ultrafine metal powder with a particle size of 0-5 μm enters the dust removal bag, and is collected in the powder collecting tank connected with the lower end of the dust removal bag after passing through the dust removal bag.

[0027] In the above-mentioned gas atomization device, preferably, the upper portion of the rod-making smelting furnace is further provided with a sampling system, and the lower end of the sampling system is in communication with the rod-making smelting furnace.

[0028] In the above-mentioned gas atomization device, preferably, the lower end of the sampling system is provided with a second plug valve, which is used to realize the communication and isolation between the rod-making smelting furnace and the sampling system.

[0029] Preferably, the upper end of the sampling system is provided with a second motor and a second worm gear, and the inside of the sampling system is provided with a second roller and a sampler; the second motor is connected to the second roller through the second worm gear, and a silk thread is wound on the second roller, and the lower end of the silk thread is hung with the sampler.

[0030] Preferably, the bar-making smelting furnace is provided with a slag removing device, a second smelting crucible and a second tundish system; the slag removing device is arranged above the inside of the bar-making smelting furnace, and the slag removing device is connected to the furnace cover of the bar-making smelting furnace through dynamic sealing. The second smelting crucible is used for smelting the metal raw material in the bar-making smelting furnace into a liquid, and the second tundish system is used for making the metal melt flow into the blank former. The slag removing device can be the slag removing device in the prior art, and the structure of the slag removing device is not specially limited in the present application.

[0031] Preferably, the mechanical arm is also used for peeling the blank in the blank former.

[0032] In the present application, the coarse powder in the first transfer tank enters the bar-making smelting furnace through the second transfer tank. Through the second motor and the second worm gear of the sampling system, the sampler can be driven to move into the inside of the metal melt in the bar-making smelting furnace, stay for 5-10s, and after the sampler is lifted, the metal melt solidifies, so that the composition of the metal sample in the sampler can be quickly detected. After obtaining the composition of the metal sample, the required elements can be added in the second feeding bin, so as to realize the control of the composition of the metal melt. In addition, after the initial blocky metal raw material is added in the second feeding bin, the metal melt in the bar-making smelting furnace is always kept in a liquid state, and then the coarse powder is directly added through the second transfer tank, that is, only the initial blocky metal raw material is added to form the metal melt in the second smelting crucible of the bar-making smelting furnace, and after the metal melt is continuously kept in a liquid state, the blocky material does not need to be added subsequently. At the same time, a certain weight proportion of carbon can be added in the second feeding bin, and the vacuum pump is used for vacuumizing to realize "vacuum carbon adding and oxygen removing", so as to reduce the content of oxygen impurities in the metal melt. In addition, the slag removing device is used for cleaning (removing) impurities such as oxides and nitrides, so as to realize the further purification of the metal melt.

[0033] In the present application, after the metal melt in the rod-making smelting furnace reaches a certain amount, it is poured into the second tundish system and flows into the lower billet former for cooling to form a billet, which can be in the shape of a sphere, a cylinder, a cone, etc. The billet former is transported to the first charging bin by a conveyor belt. Specifically, the first charging bin is provided with a conventional bin door, a connecting flange, etc. The billet former is transported to the bin door of the first charging bin by the conveyor belt. After the billet is peeled by the mechanical hand, the mechanical hand opens the bin door, loads the billet into the barrel of the first charging bin, and then closes the bin door. After the first charging bin is vacuumized by using the first vacuum pump, the inert gas is backfilled, and then the first plug valve is opened, so that the continuous smelting and atomization process can be carried out, which eliminates the operations of waiting for the crucible to cool down, vacuumizing the whole equipment and backfilling the inert gas, improves the efficiency and the service life of the crucible.

[0034] The second aspect of the present application provides a gas atomization method based on a crucible type continuous self-circulation, which adopts the above-mentioned gas atomization device based on a crucible type continuous self-circulation, and comprises the following steps:

[0035] (1) loading metal raw materials into the smelting chamber, vacuumizing and backfilling inert gas, and then using intermediate frequency electricity to heat and smelt the metal raw materials to obtain a metal melt;

[0036] (2) after the temperature of the metal melt in the smelting chamber reaches a set temperature, making the metal melt in the smelting chamber enter the atomization chamber, and using inert gas to atomize the metal melt to obtain a metal powder;

[0037] (3) the metal powder enters the first classifier for classification to obtain coarse powder with a particle size of 53-150 μm and collect the coarse powder in the first transfer tank; the metal powder with a particle size of less than 53 μm enters the second classifier for classification to obtain metal powder with a particle size of 15-53 μm and collect the metal powder in the powder collecting tank connected to the lower end of the second classifier; the metal powder with a particle size of 0-15 μm is collected in the powder collecting tank connected to the lower end of the cyclone separator after gas-solid separation by the cyclone separator; and the metal powder with a particle size of 0-5 μm enters the dust removal cloth bag and is collected in the powder collecting tank connected to the lower end of the dust removal cloth bag;

[0038] (4) after the first transfer tank and the powder collecting tank stably collect the powder, the coarse powder in the first transfer tank is sent to the second transfer tank by a feeding fan;

[0039] (5) adding blocky metal raw materials into the second charging bin, using the blocky metal raw materials in the second charging bin and the coarse powder in the second transfer tank as initial raw materials of a rod-making smelting furnace, vacuumizing and backfilling inert gas for the rod-making smelting furnace, and then using intermediate frequency electricity to heat and smelt the initial raw materials to obtain a metal melt;

[0040] (6) the metal melt in the bar-making smelting furnace is caused to flow into the billet former to be cooled to obtain a billet; the billet former is transported to the first charging bin by a conveying belt, the billet is stripped by a mechanical arm, and the stripped billet is loaded into the first charging bin by the mechanical arm; after the first charging bin is vacuumized and backfilled with inert gas to the atmospheric pressure, the first flashboard valve is opened to cause the billet in the first charging bin to be added into the smelting chamber; after the charging is completed, the first flashboard valve is closed.

[0041] In the above method, preferably, the inert gas comprises argon or nitrogen.

[0042] In the above method, preferably, in step (2), the set temperature is 1300-1800℃.

[0043] In the above method, preferably, in step (2), the atomizing pressure is 3-6 MPa, and the inert gas flow rate is 10-30 Nm 3 / min.

[0044] In the above method, preferably, step (2) specifically comprises: after the temperature of the metal melt in the smelting chamber reaches the set temperature, the tail exhaust fan is turned on, the exhaust valve on the pipeline connecting the cyclone separator and the dust cloth bag is opened after the tail exhaust fan stably operates for 5 s; the first classifier and the second classifier are sequentially opened; then the metal melt in the smelting chamber is caused to enter the atomizing chamber through the spray disc arranged at the lower end of the first tundish system, the metal melt is atomized by using inert gas to obtain metal powder.

[0045] In some specific embodiments of the present application, the set frequency of the tail exhaust fan is 30-120 Hz.

[0046] In some specific embodiments of the present application, the frequency of the classification wheel of the first classifier is 10-30 Hz.

[0047] In some specific embodiments of the present application, the frequency of the classification wheel of the second classifier is 50-80 Hz.

[0048] In the above method, preferably, in step (4), the frequency of the feeding fan is 30-80 Hz, and the air volume is 20-120 Pa.

[0049] In the method, preferably, step (5) further comprises: sampling the metal melt in the rod-making smelting furnace by using a sampling system, detecting and analyzing the metal element composition and oxygen-nitrogen content of the metal sample; after comparison and calculation with the target composition, adding the required metal elements and carbon into the rod-making smelting furnace through the second feeding bin, and simultaneously performing deoxidation treatment by using the second vacuum pump to make the vacuum degree in the rod-making smelting furnace be 0.01-10 Pa; and cleaning the oxides and nitrides and other impurities in the metal melt by using a slag removing device. Step (5) further comprises: repeating the steps of sampling, adding the required metal elements and carbon, deoxidation treatment, and slag removing until the metal element composition and oxygen-nitrogen content of the metal melt meet the requirements.

[0050] In some embodiments of the present application, in step (5), the sampling of the metal melt in the rod-making smelting furnace by using the sampling system specifically comprises: opening the second flashboard valve, starting the second motor, transmitting power to the second roller through the second worm gear, unwinding the second roller, and moving the sampler downward to the inside of the metal melt in the rod-making smelting furnace and staying for 5-10 s; reversing the second motor, winding the second roller, moving the sampler upward, solidifying the metal melt in the sampler, closing the second flashboard valve, and completing the sampling of the metal melt.

[0051] In some embodiments of the present application, in step (5), the rotating speed of the second motor is 100-1000 r / min, the transmission ratio of the second worm gear is 20:1-80:1, and the downward and upward moving speed of the sampler is 40-90 mm / min.

[0052] In some embodiments of the present application, in step (5), the metal element composition and oxygen-nitrogen content of the solidified metal sample in the sampler can be detected and analyzed by using conventional instruments and methods in the art. For example, the metal element composition can be detected and analyzed by using an ICP atomic emission spectrometer, and the oxygen-nitrogen content can be detected and analyzed by using an oxygen-nitrogen analyzer.

[0053] In the method, preferably, in step (6), the moving of the billet in the first feeding bin into the smelting chamber specifically comprises: starting the first motor, transmitting power to the first roller through the first worm gear, unwinding the first roller, and moving the barrel downward, when the barrel moves to the position of the blocking pin, the supporting plate is opened, and the billet in the barrel falls into the first smelting crucible of the smelting chamber.

[0054] In the method, preferably, after the feeding is completed, step (6) further comprises: reversing the first motor, winding the first roller, moving the barrel upward, and then closing the first flashboard valve.

[0055] In the above method, preferably, in step (6), the rotating speed of the first motor is 100-1000 r / min, the transmission ratio of the first worm gear is 20:1-80:1, and the moving speed of the barrel is 40-90 mm / min.

[0056] In the above method, preferably, in step (6), the shape of the blank comprises one or a combination of a sphere, a cylinder and a cone.

[0057] According to the specific embodiment of the present application, preferably, the above method further comprises repeating steps (4)-(6), so that continuous production of the VIGA and self-circulation of the coarse powder can be realized.

[0058] The present application provides a continuous self-circulation crucible-based gas atomization device and method. In the present application, a first plug valve is arranged between the smelting chamber and the first feeding bin, so that the smelting chamber and the first feeding bin can be connected and separated. The first motor and the first worm gear can realize automatic lifting of the barrel. The bottom of the barrel is provided with a spring and a support plate, and the inner wall of the first feeding bin is provided with a blocking pin. By reasonably using the balance force of the lever and the spring, automatic feeding of the barrel and the high-temperature crucible without contact can be realized. The rear section of the atomization chamber is provided with a double-stage wheel structure, so that the fine powder of 15-53 μm and the coarse powder of 53-150 μm can be collected at one time. The coarse powder passes through the first transfer tank and the feeding fan to reach the second transfer tank. The circulating coarse powder enters the rod-making smelting furnace. After the composition of the metal melt in the rod-making smelting furnace is obtained through the sampling system, the required elements can be added through the second feeding bin, so that the composition control of the metal melt can be realized. At the same time, the rod-making smelting furnace uses vacuum carbon addition to remove oxygen, and uses a slag removing device to clean impurities such as oxides and nitrides, so that the metal melt can be further purified. Finally, the metal melt in the rod-making smelting furnace is cast into a blank forming device to prepare a blank. The blank is moved to the first feeding bin above the smelting chamber using a conveyor belt. The blank is peeled off by a robot, and then the blank is loaded into the first feeding bin by the robot, so that continuous production and self-circulation of the coarse powder can be realized.

[0059] The technical scheme of the present application has at least the following beneficial effects:

[0060] (1) The first plug valve and the first feeding bin are used to separate smelting and feeding in the present application. After the coarse powder is transported by the feeding fan, the blank is prepared by the rod-making smelting furnace, and then the blank is loaded into the first feeding bin by the robot, so that the smelting chamber is fed, and the continuous production mode of the VIGA device is realized. Compared with the traditional single-furnace production mode, on the one hand, the production efficiency is improved without waiting for the crucible to cool and re-evacuate, and on the other hand, the service life of the smelting crucible is improved by reducing the cold and hot impact on the crucible.

[0061] (2) The present application can recycle the coarse powder for production, and further purify the metal melt in the rod-making smelting furnace by vacuum carbon addition to remove oxygen and use a slag cleaning device to clean impurities such as oxides and nitrides. And by adding the required elements through the second feeding bin, the metal melt in the rod-making smelting furnace is sampled through the sampling system, and then detected to ensure that the composition of the metal melt meets the requirements, and finally the performance of the printed part is guaranteed.

[0062] (3) The present application only needs a small amount of blocky metal raw material (such as rod) as "ignition fuel" in the initial stage of atomization, and once the metal melt in the rod-making smelting furnace is formed, the raw material in it can always be kept in a molten state, and only coarse powder needs to be continuously added to the rod-making smelting furnace, which can greatly reduce the proportion of rod use and realize self-circulation of coarse powder materials.

[0063] (4) The present application uses a feeding fan to transport coarse powder to the rod-making smelting furnace, and the first feeding bin is designed ingeniously using the force of spring and lever to realize automatic feeding of the first smelting crucible in the smelting chamber, reducing manpower and material resources, and the metal powder is always protected in the pipeline inert gas, ensuring the safety of on-site production.

[0064] In summary, the present application provides a continuous self-circulating gas atomization device and method based on a crucible, which realizes the continuous and coarse powder self-circulation of VIGA, reduces the waste of manpower and material resources, and can further promote the industrialization process of VIGA technology. BRIEF DESCRIPTION OF DRAWINGS

[0065] Figure 1 The structure schematic diagram of the continuous self-circulating gas atomization device based on a crucible for example 1 is provided.

[0066] Figure 2 The partial enlarged schematic diagram of the support plate at the bottom of the material cylinder in the continuous self-circulating gas atomization device based on a crucible for example 1 is provided.

[0067] Figure 3 The partial enlarged schematic diagram of the support plate at the bottom of the material cylinder in the continuous self-circulating gas atomization device based on a crucible for example 1 is provided.

[0068] BRIEF DESCRIPTION OF DRAWINGS

[0069] 1-melting chamber, 2-atomization chamber, 3-first feeding bin, 4-first gate valve, 5-first motor, 6-first worm gear, 7-first roller, 8-barrel, 9-block pin, 10-first vacuum pump, 11-first pneumatic valve, 12-second pneumatic valve, 13-first inert gas pipeline, 14-first classifier, 15-second classifier, 16-cyclone separator, 17-dust cloth bag, 18-tail exhaust fan, 19-first transfer tank, 20-powder collecting tank, 21-feeding fan, 22-second transfer tank, 23-rod making smelting furnace, 24-second feeding bin, 25-second gate valve, 26-second motor, 27-second worm gear, 28-second roller, 29-sampler, 30-slag removal device, 31-second vacuum pump, 32-second inert gas pipeline, 33-conveying belt, 34-billet former, 35-robot; 801-spring, 802-supporting plate, 803-lifting lug. DETAILED DESCRIPTION

[0070] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present application, the technical solutions of the present application are described in detail as follows, but cannot be understood as limiting the implementable scope of the present application.

[0071] Example 1

[0072] The present embodiment provides a gas atomization device based on a crucible type continuous self-circulation, and the structure thereof is shown in Figure 1 .

[0073] The device comprises:

[0074] a melting chamber 1, an atomization chamber 2, a first feeding bin 3, a first gate valve 4, a first vacuum pump 10, a first inert gas pipeline 13, a first classifier 14, a second classifier 15, a cyclone separator 16, a dust cloth bag 17, a tail exhaust fan 18, a first transfer tank 19, a powder collecting tank 20, a feeding fan 21, a second transfer tank 22, a rod making smelting furnace 23, a second feeding bin 24, a second vacuum pump 31, a second inert gas pipeline 32, a conveying belt 33, a billet former 34, and a robot 35.

[0075] The melting chamber 1 is arranged above the atomization chamber 2, and the lower end of the melting chamber 1 is communicated with the atomization chamber 2.

[0076] The first feeding bin 3 is arranged above the melting chamber 1, and the lower end of the first feeding bin 3 is provided with the first gate valve 4, which is used to realize the communication and separation between the melting chamber 1 and the first feeding bin 3; the sidewall of the first feeding bin 3 is provided with the first inert gas pipeline 13.

[0077] The upper end of the first feeding bin 3 is provided with a first motor 5 and a first worm gear 6, and the inside of the first feeding bin 3 is provided with a first roller 7, a material cylinder 8 and a blocking pin 9; the first motor 5 is connected to the first roller 7 through the first worm gear 6, the first roller 7 is wound with a silk thread, the lower end of the silk thread is hung with the material cylinder 8, the lower part of the inner wall of the first feeding bin 3 is provided with the blocking pin 9, and the blocking pin 9 is provided with a roller;

[0078] The side wall of the first feeding bin 3 and the side wall of the atomization chamber 2 are connected to the first vacuum pump 10 through a pipeline; the pipeline connecting the side wall of the atomization chamber 2 and the first vacuum pump 10 is provided with a first pneumatic valve 11; the pipeline connecting the side wall of the first feeding bin 3 and the first vacuum pump 10 is provided with a second pneumatic valve 12;

[0079] The lower end of the atomization chamber 2 is communicated with the first classifier 14, the first classifier 14 is communicated with the second classifier 15, the second classifier 15 is communicated with the cyclone separator 16, the cyclone separator 16 is communicated with the dust cloth bag 17, an exhaust valve is arranged on the pipeline connecting the cyclone separator 16 and the dust cloth bag 17, the upper end of the dust cloth bag 17 is connected with a tail exhaust fan 18, the lower end of the first classifier 14 is connected with a first transfer tank 19, the number of the powder collecting tanks 20 is three, and the lower ends of the second classifier 15, the cyclone separator 16 and the dust cloth bag 17 are respectively connected with the powder collecting tanks 20;

[0080] The lower end of the first transfer tank 19 is communicated with the upper end of a second transfer tank 22 through a third pneumatic valve and a feeding fan 21;

[0081] A rod-making smelting furnace 23 is arranged below the second transfer tank 22, and the lower end of the second transfer tank 22 is communicated with the rod-making smelting furnace 23; a second feeding bin 24 is arranged above the rod-making smelting furnace 23, and the lower end of the second feeding bin 24 is communicated with the rod-making smelting furnace 23, and the second feeding bin 24 is used for adding blocky metal raw materials into the rod-making smelting furnace 23;

[0082] A sampling system is further arranged above the rod-making smelting furnace 23, and the lower end of the sampling system is communicated with the rod-making smelting furnace 23; the lower end of the sampling system is provided with a second plug valve 25, and the second plug valve 25 is used for realizing the communication and separation between the rod-making smelting furnace 23 and the sampling system;

[0083] The upper end of the sampling system is provided with a second motor 26 and a second worm gear 27, and the inside of the sampling system is provided with a second roller 28 and a sampler 29; the second motor 26 is connected to the second roller 28 through the second worm gear 27, the second roller 28 is wound with a silk thread, and the lower end of the silk thread is hung with the sampler 29;

[0084] The side wall of the rod-making smelting furnace 23 is provided with a second inert gas pipeline 32, and the side wall of the rod-making smelting furnace 23 is connected to a second vacuum pump 31 through a pipeline;

[0085] A blank former 34 is arranged below the rod-making smelting furnace 23 and is arranged above the conveying belt 33 which is used to transport the blank former 34 to the first charging bin 3. A mechanical arm 35 is used to skin the blank in the blank former 34 and to load the skinned blank into the first charging bin 3.

[0086] In this embodiment, the smelting chamber 1 is provided with a first smelting crucible and a first tundish system, and the lower end of the smelting chamber 1 is communicated with the atomization chamber 2 through the first tundish system. The lower end of the first tundish system is provided with a spray disc, and the spray disc is provided with a flow guide nozzle and an inert gas valve. The diameter of the flow guide nozzle is 3-6 mm. The first smelting crucible is used to smelt the metal raw material in the smelting chamber 1 into a liquid, and the spray disc arranged at the lower end of the first tundish system is used to spray the metal melt into the atomization chamber 2.

[0087] In this embodiment, the barrel 8 is a hollow structure, and the bottom of the barrel 8 is uniformly provided with 4-8 support plates 802 as a bottom plate. The outer wall of the barrel 8 is provided with a lifting lug 803, and the lower edge of the barrel 8 is fixedly connected with a bearing. The middle section of the support plate 802 is connected with the bearing fixedly connected with the lower edge of the barrel 8, and the outer side of the support plate 802 is connected with the lifting lug 803 of the outer wall of the barrel 8 through a spring 801. The support plate 802 is used to realize the opening and closing of the lower end of the barrel 8, and the opening and closing angle of the support plate 802 is 0-90°. The closing and opening states of the support plate 802 at the bottom of the barrel 8 are shown in Figs. 8 and 9. Figure 2 and Figure 3

[0088] In this embodiment, the rod-making smelting furnace 23 is provided with a slag pushing device 30, a second smelting crucible and a second tundish system. The slag pushing device 30 is arranged above the inside of the rod-making smelting furnace 23 and is connected with the furnace cover of the rod-making smelting furnace 23 through dynamic sealing. The second smelting crucible is used to smelt the metal raw material in the rod-making smelting furnace 23 into a liquid, and the second tundish system is used to make the metal melt flow into the blank former 34.

[0089] Embodiment 2

[0090] This embodiment provides a gas atomization method based on a crucible type continuous self-circulation, which adopts the gas atomization device based on a crucible type continuous self-circulation provided in embodiment 1.

[0091] The method comprises the following steps:

[0092] (1) Metal raw material (generally block-shaped metal raw material) is loaded into the first smelting crucible of the smelting chamber 1. After vacuumizing and backfilling inert gas, the metal raw material is heated and smelted by using intermediate frequency electricity to obtain a metal melt;

[0093] ​(2) After the temperature of the metal melt in the smelting chamber 1 reaches 1300-1800℃, the tail exhaust fan 18 is turned on, the set frequency of the tail exhaust fan 18 is 30-120 Hz, after the tail exhaust fan 18 is stably running for 5s, the exhaust valve on the pipeline connecting the cyclone separator 16 and the dust cloth bag 17 is opened; the first classifier 14 and the second classifier 15 are opened in turn, the frequency of the classification wheel of the first classifier 14 is 10-30 Hz, the frequency of the classification wheel of the second classifier 15 is 50-80 Hz; then the first smelting crucible is poured, the metal melt enters the atomization chamber 2 through the spray disc arranged at the lower end of the first intermediate ladle system, the metal melt is atomized using inert gas, the atomization pressure is 3-6 MPa, the inert gas flow is 10-30 Nm 3 / min, and metal powder is obtained;

[0094] (3) The metal powder enters the first classifier 14 for classification, and coarse powder with a particle size of 53-150 μm is obtained and collected in the first transfer tank 19; metal powder with a particle size of less than 53 μm enters the second classifier 15 for classification, and metal powder with a particle size of 15-53 μm is obtained and collected in the powder collecting tank 20 connected to the lower end of the second classifier 15, which is the finished metal powder; metal powder with a particle size of 0-15 μm is collected in the powder collecting tank 20 connected to the lower end of the cyclone separator 16 after gas-solid separation by the cyclone separator 16; metal powder with a particle size of 0-5 μm enters the dust cloth bag 17 and is collected in the powder collecting tank 20 connected to the lower end of the dust cloth bag 17;

[0095] (4) After the first transfer tank 19 and the powder collecting tank 20 are stably filled with powder, the third pneumatic valve at the lower end of the first transfer tank 19 and the feeding fan 21 are turned on, and the coarse powder in the first transfer tank 19 is blown to the second transfer tank 22 by the feeding fan 21, the frequency of the feeding fan 21 is 30-80 Hz, and the air volume is 20-120 Pa;

[0096] (5) adding the bulk metal raw material into the second charging bin 24, taking the bulk metal raw material in the second charging bin 24 and the coarse powder in the second transfer tank 22 as the initial raw material of the rod-making smelting furnace 23, after vacuumizing and backfilling inert gas of the rod-making smelting furnace 23, using the intermediate frequency electricity to heat and smelt the initial raw material, obtaining the metal melt; using the sampling system to sample the metal melt in the rod-making smelting furnace 23, opening the second gate valve 25, starting the second motor 26, transmitting power to the second roller 28 through the second worm gear 27, the second roller 28 paying out wire, making the sampler 29 move downward to the inside of the metal melt in the second smelting crucible of the rod-making smelting furnace 23, staying for 5-10s; reversing the second motor 26, the second roller 28 taking up wire, the sampler 29 moving upward, the metal melt in the sampler 29 solidifying, closing the second gate valve 25, completing the sampling of the metal melt; wherein the rotating speed of the second motor 26 is 100-1000r / min, the transmission ratio of the second worm gear 27 is 20:1-80:1, the downward and upward moving speed of the sampler 29 is 40-90mm / min; using the conventional instrument and method in the art to detect and analyze the metal element composition and oxygen-nitrogen content of the solidified metal sample in the sampler 29; after comparison and calculation with the target composition, adding the required metal elements (such as silicon, manganese, chromium, etc. volatile elements) and carbon into the rod-making smelting furnace 23 through the second charging bin 24, at the same time, using the second vacuum pump 31 to make the vacuum degree in the rod-making smelting furnace 23 be 0.01-10Pa, carrying out deoxidation treatment; using the slag removing device 30 to clean the impurities such as oxides and nitrides in the metal melt; repeating the steps of sampling, adding the required metal elements and carbon, deoxidation treatment, and slag removing until the metal element composition and oxygen-nitrogen content of the metal melt meet the requirements;

[0097] (6) pouring the second smelting crucible in the pouring and rod-making smelting furnace 23 to make the metal melt flow into the billet former 34 through the second tundish system for cooling to obtain a billet, the shape of the billet including one or a combination of several of a sphere, a cylinder and a cone; transporting the billet former 34 to the first charging bin 3 through the conveying belt 33, peeling the billet through the mechanical arm 35, opening the bin door of the first charging bin 3 through the mechanical arm 35, and loading the peeled billet into the barrel 8 of the first charging bin 3; after vacuumizing and backfilling the first charging bin 3 with inert gas to the atmospheric pressure, opening the first flashboard valve 4, starting the first motor 5, transmitting power to the first roller 7 through the first worm gear 6, unwinding the first roller 7, moving the barrel 8 downward, opening the support plate 802 when the barrel 8 moves to the position of the blocking pin 9, and dropping the billet in the barrel 8 into the first smelting crucible in the smelting chamber 1; after the charging is completed, reversing the first motor 5, winding the first roller 7, moving the barrel 8 upward, and then closing the first flashboard valve 4; wherein the rotating speed of the first motor 5 is 100-1000 r / min, the transmission ratio of the first worm gear 6 is 20:1-80:1, and the downward and upward moving speed of the barrel 8 is 40-90 mm / min.

[0098] (7) repeating steps (4)-(6) to realize continuous production of the VIGA and self-circulation of the coarse powder.

[0099] In this embodiment, the inert gas includes argon or nitrogen.

[0100] Example 3

[0101] This embodiment provides a gas atomization method based on a crucible type continuous self-circulation, which uses the gas atomization device based on a crucible type continuous self-circulation provided in Example 1.

[0102] The method of this embodiment is used to prepare a 316L stainless steel metal powder for metal 3D printing.

[0103] The method includes the following steps:

[0104] (1) loading 80 kg of 316L rod and 200 kg of coarse powder into the first smelting crucible in the smelting chamber 1, vacuumizing and backfilling with inert gas, heating and smelting the metal raw material using a medium frequency electric source to obtain a metal melt;

[0105] (2) when the temperature of the metal melt in the smelting chamber 1 is about 1600±30℃, the tail exhaust fan 18 is opened, the set frequency of the tail exhaust fan 18 is 30-50Hz, after the tail exhaust fan 18 is stably operated for 5s, the exhaust valve on the pipeline connecting the cyclone separator 16 and the dust cloth bag 17 is opened; the first classifier 14 and the second classifier 15 are opened in sequence, the frequency of the classification wheel of the first classifier 14 is 16Hz, and the frequency of the classification wheel of the second classifier 15 is 62Hz; then the first smelting crucible is poured, the metal melt enters the atomization chamber 2 through the spray disc provided at the lower end of the first intermediate ladle system, the diameter of the flow guide nozzle on the spray disc is 4mm, and the inert gas valve on the spray disc is opened, the inert gas is used to atomize the metal melt, the atomization pressure is 4.5MPa, the inert gas flow is 18-25Nm 3 / min, and the metal powder is obtained;

[0106] (3) the metal powder enters the first classifier 14 for classification, the coarse powder with a particle size of 53-150μm is obtained and collected in the first transfer tank 19; the metal powder with a particle size of less than 53μm enters the second classifier 15 for classification, the metal powder with a particle size of 15-53μm is obtained and collected in the powder collecting tank 20 connected to the lower end of the second classifier 15, which is the finished metal powder; the metal powder with a particle size of 0-15μm is collected in the powder collecting tank 20 connected to the lower end of the cyclone separator 16 after gas-solid separation by the cyclone separator 16; the metal powder with a particle size of 0-5μm enters the dust cloth bag 17 and is collected in the powder collecting tank 20 connected to the lower end of the dust cloth bag 17;

[0107] (4) when the loading in the first transfer tank 19 reaches 50kg and the powder is stably collected in the powder collecting tank 20, the third pneumatic valve at the lower end of the first transfer tank 19 and the feeding fan 21 are opened, the coarse powder in the first transfer tank 19 is blown to the second transfer tank 22 by the feeding fan 21, the frequency of the feeding fan 21 is 42Hz, and the air volume is 20-80Pa;

[0108] (5) adding 100 kg of 316L block into the second charging bin 24, taking 100 kg of 316L block in the second charging bin 24 and 50 kg of coarse powder in the second transfer tank 22 as the initial raw material of the bar-making smelting furnace 23, vacuumizing the bar-making smelting furnace 23 to 0.05 Pa, after backfilling inert gas, using intermediate frequency electricity to heat and smelt the initial raw material, obtaining a metal melt; using a sampling system to sample the metal melt in the bar-making smelting furnace 23, opening the second gate valve 25, starting the second motor 26, transmitting power to the second roller 28 through the second worm gear 27, the second roller 28 paying out wire, making the sampler 29 move downward to the inside of the metal melt in the second smelting crucible of the bar-making smelting furnace 23, staying for 5-10 s; reversing the second motor 26, the second roller 28 taking up wire, the sampler 29 moving upward, the metal melt in the sampler 29 solidifying, closing the second gate valve 25, completing sampling of the metal melt; wherein the rotating speed of the second motor 26 is 100-300 r / min, the transmission ratio of the second worm gear 27 is 20:1-50:1, the downward and upward moving speed of the sampler 29 is 40-80 mm / min; using conventional instruments and methods in the art to detect and analyze the metal element composition and oxygen-nitrogen content of the solidified metal sample in the sampler 29; after comparison and calculation with the target composition, adding 0.8 g of carbon and 0.6 g of manganese into the bar-making smelting furnace 23 through the second charging bin 24, at the same time, using the second vacuum pump 31 to make the vacuum degree in the bar-making smelting furnace 23 be 0.05 Pa, carrying out deoxidation treatment; using the slag removing device 30 to clean the metal melt from impurities such as oxides and nitrides; repeating the steps of sampling, adding the required metal elements and carbon, deoxidation treatment, and slag removal until the metal element composition and oxygen-nitrogen content of the metal melt meet the requirements;

[0109] (6) pouring the second smelting crucible in the pouring bar smelting furnace 23, so that the metal melt flows into the billet former 34 through the second tundish system for cooling to obtain a billet, the shape of the billet including one or a combination of several of a sphere, a cylinder and a cone; the billet former 34 is transported to the first charging bin 3 through the conveying belt 33, the billet is stripped by the mechanical arm 35, then the door of the first charging bin 3 is opened by the mechanical arm 35, and the stripped billet is loaded into the barrel 8 of the first charging bin 3; the first charging bin 3 is vacuumized to 0.5 Pa, then the inert gas is backfilled to the atmospheric pressure (101 kPa), the first plug valve 4 is opened, the first motor 5 is started, power is transmitted to the first roller 7 through the first worm gear 6, the first roller 7 is unwound, the barrel 8 moves downward, when the barrel 8 moves to the position of the stop pin 9, the support plates 802 are opened, the number of the support plates 802 is 4, and the billet in the barrel 8 falls into the first smelting crucible of the smelting chamber 1; after the charging is completed, the first motor 5 is reversed, the first roller 7 is wound, the barrel 8 moves upward, and then the first plug valve 4 is closed; wherein the rotating speed of the first motor 5 is 100-300 r / min, the transmission ratio of the first worm gear 6 is 20:1-50:1, and the downward and upward moving speed of the barrel 8 is 40-80 mm / min;

[0110] (7) repeating steps (4)-(6) to realize the continuous production of the VIGA and the self-circulation of the coarse powder.

[0111] In the embodiment, the inert gas is argon.

[0112] In the embodiment, the 316L metal powder with a particle size of 15-53 μm is prepared, and the particle size is tested by using a laser particle size analyzer, and the D50 value is 27 μm≤D50≤35 μm.

[0113] Embodiment 4

[0114] The embodiment provides a gas atomization method based on a crucible type continuous self-circulation, and the method uses the gas atomization device based on the crucible type continuous self-circulation provided in the embodiment 1.

[0115] The method provided in the embodiment prepares a GH4169 stainless steel metal powder for metal 3D printing.

[0116] The method comprises the following steps:

[0117] (1) 60 kg of GH4169 bar and 230 kg of coarse powder are loaded into the first smelting crucible of the smelting chamber 1, after vacuumization and backfilling of the inert gas, the metal raw material is heated and smelted by using a medium frequency electric, to obtain a metal melt;

[0118] (2) when the temperature of the metal melt in the smelting chamber 1 is about 1620±30℃, the tail exhaust fan 18 is opened, the set frequency of the tail exhaust fan 18 is 30-50Hz, after the tail exhaust fan 18 is stably operated for 5s, the exhaust valve on the pipeline connecting the cyclone separator 16 and the dust cloth bag 17 is opened; the first classifier 14 and the second classifier 15 are opened in sequence, the frequency of the classification wheel of the first classifier 14 is 18Hz, and the frequency of the classification wheel of the second classifier 15 is 60Hz; then the first smelting crucible is poured, the metal melt enters the atomization chamber 2 through the spray disc provided at the lower end of the first intermediate ladle system, the diameter of the flow guide nozzle on the spray disc is 4.5mm, and the inert gas valve on the spray disc is opened, the inert gas is used to atomize the metal melt, the atomization pressure is 5.0MPa, the inert gas flow is 18-25Nm 3 / min, and the metal powder is obtained;

[0119] (3) the metal powder enters the first classifier 14 for classification, the coarse powder with a particle size of 53-150μm is obtained and collected in the first transfer tank 19; the metal powder with a particle size of less than 53μm enters the second classifier 15 for classification, the metal powder with a particle size of 15-53μm is obtained and collected in the powder collecting tank 20 connected to the lower end of the second classifier 15, which is the metal powder finished product; the metal powder with a particle size of 0-15μm is collected in the powder collecting tank 20 connected to the lower end of the cyclone separator 16 after gas-solid separation by the cyclone separator 16; the metal powder with a particle size of 0-5μm enters the dust cloth bag 17 and is collected in the powder collecting tank 20 connected to the lower end of the dust cloth bag 17;

[0120] (4) when the loading in the first transfer tank 19 reaches 50kg and the powder is stably collected in the powder collecting tank 20, the third pneumatic valve at the lower end of the first transfer tank 19 and the feeding fan 21 are opened, the coarse powder in the first transfer tank 19 is blown to the second transfer tank 22 by the feeding fan 21, the frequency of the feeding fan 21 is 42Hz, and the air volume is 20-80Pa;

[0121] (5) adding 120 kg of blocky GH4169 into the second charging bin 24, taking 100 kg of blocky 316L in the second charging bin 24 and 50 kg of coarse powder in the second transfer tank 22 as initial raw materials of the bar-making smelting furnace 23, vacuumizing the bar-making smelting furnace 23 to 0.05 Pa, after backfilling inert gas, using intermediate frequency electricity to heat and smelt the initial raw materials, obtaining a metal melt; using a sampling system to sample the metal melt in the bar-making smelting furnace 23, opening the second gate valve 25, starting the second motor 26, transmitting power to the second roller 28 through the second worm gear 27, the second roller 28 paying out wire, making the sampler 29 move downward to the inside of the metal melt in the second smelting crucible of the bar-making smelting furnace 23, staying for 5-10 s; reversing the second motor 26, the second roller 28 taking up wire, the sampler 29 moving upward, the metal melt in the sampler 29 solidifying, closing the second gate valve 25, completing sampling of the metal melt; wherein the rotating speed of the second motor 26 is 100-300 r / min, the transmission ratio of the second worm gear 27 is 20:1-50:1, the downward and upward moving speed of the sampler 29 is 40-80 mm / min; using conventional instruments and methods in the art to detect and analyze the metal element composition and oxygen-nitrogen content of the solidified metal sample in the sampler 29; after comparison and calculation with the target composition, adding 0.5 g of carbon, 0.2 g of manganese and 0.81 g of niobium into the bar-making smelting furnace 23 through the second charging bin 24, at the same time using the second vacuum pump 31 to make the vacuum degree in the bar-making smelting furnace 23 be 0.05 Pa, carrying out deoxidation treatment; using the slag removing device 30 to clean the metal melt from impurities such as oxides and nitrides; repeating the steps of sampling, adding the required metal elements and carbon, deoxidation treatment, and slag removal until the metal element composition and oxygen-nitrogen content of the metal melt meet the requirements;

[0122] (6) pouring the second smelting crucible in the pouring rod smelting furnace 23, so that the metal melt flows into the billet former 34 through the second tundish system for cooling to obtain a billet, the shape of the billet including one or a combination of several of a sphere, a cylinder and a cone; the billet former 34 is transported to the first charging bin 3 through the conveying belt 33, the billet is stripped by the mechanical arm 35, then the bin door of the first charging bin 3 is opened by the mechanical arm 35, and the stripped billet is loaded into the barrel 8 of the first charging bin 3; the first charging bin 3 is vacuumized to 0.5 Pa, then the inert gas is backfilled to the atmospheric pressure (101 kPa), the first plug valve 4 is opened, the first motor 5 is started, power is transmitted to the first roller 7 through the first worm gear 6, the first roller 7 is unwound, the barrel 8 moves downward, when the barrel 8 moves to the position of the stop pin 9, the support plates 802 are opened, the number of the support plates 802 is 8, and the billet in the barrel 8 falls into the first smelting crucible of the smelting chamber 1; after the charging is completed, the first motor 5 is reversed, the first roller 7 is wound, the barrel 8 moves upward, and then the first plug valve 4 is closed; wherein the rotating speed of the first motor 5 is 100-300 r / min, the transmission ratio of the first worm gear 6 is 20:1-50:1, and the downward and upward moving speed of the barrel 8 is 40-80 mm / min;

[0123] (7) repeating steps (4)-(6) to realize the continuous production of VIGA and the self-circulation of coarse powder.

[0124] In the embodiment, the inert gas is argon.

[0125] In the embodiment, the inert gas is argon.

[0126] Comparative Example 1

[0127] The present comparative example provides a device and a method of traditional VIGA technology. The device includes a conventional smelting chamber, an atomization chamber, a "through powder" screening and grading system, etc. The method includes: manually loading metal raw materials (including element materials and rods) into a smelting crucible in the smelting chamber, using intermediate frequency electricity to heat and smelt the metal raw materials to obtain a metal melt; pouring the smelting crucible, the metal melt enters the atomization chamber through the spray disc arranged at the lower end of the tundish system in the smelting chamber, using high-pressure inert gas to atomize the metal melt to obtain "through powder"; after screening and grading, 15-53 μm metal powder for 3D printing is obtained, and at the same time, 53-150 μm by-products (i.e. coarse powder) are also produced; after the smelting crucible is cooled, the metal raw materials (including 53-150 μm coarse powder and rods, etc.) are manually loaded into the smelting crucible again, then vacuumization and inert gas backfilling are performed, and the operations of smelting and atomization are repeated.

[0128] The results of the comparison between the above embodiments 3-4 and the conventional VIGA technology of Comparative Example 1 are shown in Table 1.

[0129] Table 1

[0130]

[0131] In summary, the continuous self-circulation gas atomization device and method based on a crucible provided by the present application realize the continuous self-circulation of VIGA and reduce the waste of manpower and material resources, which can further promote the industrialization process of VIGA technology.

Claims

1. A continuous self-circulating gas atomization device based on a crucible, comprising: The smelting chamber, the atomization chamber, the first feeding bin, the first plug valve, the first vacuum pump, the first inert gas pipeline, the first classifier, the second classifier, the cyclone separator, the dust cloth bag, the tail exhaust fan, the first transfer tank, the powder collecting tank, the feeding fan, the second transfer tank, the rod making smelting furnace, the second feeding bin, the second vacuum pump, the second inert gas pipeline, the conveyor belt, the blank former and the mechanical hand are arranged in the smelting chamber. The smelting chamber is arranged above the atomization chamber, and the lower end of the smelting chamber is communicated with the atomization chamber. The first feeding bin is arranged above the smelting chamber, and the lower end of the first feeding bin is provided with a first plug valve for realizing the communication and separation between the smelting chamber and the first feeding bin. The side walls of the first feeding bin and the atomization chamber are connected with the first vacuum pump through a pipeline, the upper end of the first feeding bin is provided with a first motor and a first worm gear, and the inside of the first feeding bin is provided with a first roller, a barrel and a blocking pin. The first motor is connected with the first roller through the first worm gear, a wire is wound on the first roller, the lower end of the wire is hung with the barrel, and the lower part of the inner wall of the first feeding bin is provided with the blocking pin. The lower end of the atomization chamber is communicated with the first classifier, the first classifier is communicated with the second classifier, the second classifier is communicated with the cyclone separator, the cyclone separator is communicated with the dust cloth bag, the dust cloth bag is connected with the tail exhaust fan, the lower end of the first classifier is connected with the first transfer tank, and the lower ends of the second classifier, the cyclone separator and the dust cloth bag are respectively connected with the powder collecting tank. The lower end of the first transfer tank is communicated with the upper end of the second transfer tank through the feeding fan. The lower end of the second transfer tank is communicated with the rod making smelting furnace, the second feeding bin is arranged above the rod making smelting furnace, and the lower end of the second feeding bin is communicated with the rod making smelting furnace. The side wall of the rod-making smelting furnace is provided with a second inert gas pipeline, and the side wall of the rod-making smelting furnace is connected to a second vacuum pump through the pipeline; the upper portion of the rod-making smelting furnace is further provided with a sampling system, and the lower end of the sampling system is communicated with the rod-making smelting furnace; the lower end of the sampling system is provided with a second plug valve, which is used to realize the communication and isolation between the rod-making smelting furnace and the sampling system; the upper end of the sampling system is provided with a second motor and a second worm gear, and the inside of the sampling system is provided with a second roller and a sampler; the second motor is connected to the second roller through the second worm gear, a silk thread is wound on the second roller, and the lower end of the silk thread is hung with the sampler; The lower portion of the rod-making smelting furnace is provided with a billet former, the billet former is located above the conveying belt, and the conveying belt is used to transport the billet former to the first feeding bin; and the mechanical arm is used to at least load the billet in the billet former into the first feeding bin.

2. The crucible-based continuous self-circulating gas atomization apparatus of claim 1, wherein, The smelting chamber is provided with a first smelting crucible and a first tundish system, and the lower end of the smelting chamber is communicated with the atomization chamber through the first tundish system.

3. The crucible-based continuous self-circulating gas atomization apparatus of claim 2, wherein, The lower end of the first tundish system is provided with a spray disc, and the spray disc is provided with a flow guide nozzle, and the diameter of the flow guide nozzle is 3-6 mm.

4. The crucible-based continuous self-circulating gas atomization apparatus of claim 1, wherein, The blocking pin is provided with a roller.

5. The crucible-based continuous self-circulating gas atomization apparatus of claim 1, wherein, An exhaust valve is arranged on the pipeline connected between the cyclone separator and the dust removal bag.

6. The crucible-based continuous self-circulating gas atomization apparatus of claim 1, wherein, The rod-making smelting furnace is provided with a slag pushing device, a second smelting crucible and a second tundish system; the slag pushing device is arranged above the inside of the rod-making smelting furnace, and the slag pushing device is connected to the furnace cover of the rod-making smelting furnace through dynamic sealing.

7. A continuous self-circulation based gas atomization method, the method uses the continuous self-circulation based gas atomization device of any one of claims 1-6, and the method comprises the following steps: (1) loading metal raw materials into the smelting chamber, after vacuumizing and backfilling inert gas, using intermediate frequency electricity to heat and smelt the metal raw materials to obtain metal melt; (2) after the temperature of the metal melt in the smelting chamber reaches the set temperature, making the metal melt in the smelting chamber enter the atomization chamber, using inert gas to atomize the metal melt to obtain metal powder; (3) the metal powder enters the first classifier to be classified to obtain coarse powder with a particle size of 53-150 μm and collect the coarse powder in the first transfer tank; the metal powder with a particle size of less than 53 μm enters the second classifier to be classified to obtain metal powder with a particle size of 15-53 μm and collect the metal powder in the powder collecting tank connected to the lower end of the second classifier, which is the metal powder product; the metal powder with a particle size of 0-15 μm is collected in the powder collecting tank connected to the lower end of the cyclone separator after gas-solid separation by the cyclone separator; the metal powder with a particle size of 0-5 μm enters the dust removal bag and is collected in the powder collecting tank connected to the lower end of the dust removal bag; (4) after the first transfer tank and the powder collecting tank stably collect the powder, the feeding fan is used to send the coarse powder in the first transfer tank to the second transfer tank. (5) adding the bulk metal raw material into the second charging bin, taking the bulk metal raw material in the second charging bin and the coarse powder in the second transfer tank as the initial raw material of the rod-making smelting furnace, after vacuumizing and backfilling inert gas to the rod-making smelting furnace, using the intermediate frequency electricity to heat and smelt the initial raw material, obtaining the metal melt; using the sampling system to sample the metal melt in the rod-making smelting furnace, opening the second flashboard valve, starting the second motor, transmitting power to the second roller through the second worm gear, the second roller paying out wire, making the sampler move downward to the inside of the metal melt in the rod-making smelting furnace, staying for 5-10s; reversing the second motor, the second roller winding up wire, the sampler moving upward, the metal melt in the sampler solidifying, closing the second flashboard valve, completing the sampling of the metal melt, detecting and analyzing the metal element composition and oxygen-nitrogen content of the metal sample; after comparison and calculation with the target composition, adding the required metal elements and carbon into the rod-making smelting furnace through the second charging bin, at the same time, using the second vacuum pump to make the vacuum degree of the rod-making smelting furnace be 0.01-10Pa, carrying out deoxidation treatment; (6) making the metal melt in the rod-making smelting furnace flow into the blank forming device to cool, obtaining the blank; transporting the blank forming device to the first charging bin through the conveying belt, peeling the blank through the mechanical arm, then loading the peeled blank into the first charging bin through the mechanical arm; after vacuumizing and backfilling inert gas to the first charging bin to the atmospheric pressure, opening the first flashboard valve, starting the first motor, transmitting power to the first roller through the first worm gear, the first roller paying out wire, the barrel moving downward, when the barrel moves to the position of the blocking pin, the supporting plate opens, the blank in the barrel falls into the first smelting crucible of the smelting chamber; after completing the feeding, reversing the first motor, the first roller winding up wire, the barrel moving upward, then closing the first flashboard valve.

8. The continuous self-circulating gas-atomizing method based on a crucible according to claim 7, wherein, The inert gas includes argon or nitrogen.

9. The continuous self-circulating gas-atomizing method based on a crucible according to claim 7, wherein, In step (2), the setting temperature is 1300-1800℃; the atomizing pressure is 3-6 MPa, and the inert gas flow rate is 10-30 Nm 3 / min.

10. The continuous self-circulating gas-atomizing method based on a crucible according to claim 7 or 9, wherein, Step (2) specifically comprises: after the temperature of the metal melt in the smelting chamber reaches the set temperature, opening the tail exhaust fan, after the tail exhaust fan stably operates for 5s, opening the exhaust valve on the pipeline connecting the cyclone separator and the dust cloth bag; sequentially opening the first classifier and the second classifier; then making the metal melt in the smelting chamber enter the atomizing chamber through the spray disc arranged at the lower end of the first intermediate ladle system, using the inert gas to atomize the metal melt, obtaining the metal powder.

11. The continuous self-circulating gas-atomizing method based on a crucible according to claim 10, wherein, The set frequency of the tail exhaust fan is 30-120Hz.

12. The crucible-based continuous self-circulating gas- atomization process of claim 7, wherein, In step (3), the frequency of the classification wheel of the first classifier is 10-30Hz.

13. The crucible-based continuous self-circulating gas- atomization process of claim 7, wherein, In step (3), the frequency of the classification wheel of the second classifier is 50-80Hz.

14. The crucible-based continuous self-circulating gas- atomization process of claim 7, wherein, In step (4), the frequency of the feeding fan is 30-80Hz, and the air volume is 20-120Pa.

15. The crucible-based continuous self-circulating gas- atomization process of claim 7, wherein, Step (5) further comprises: using the slag removing device to clean the oxide and nitride impurities in the metal melt.

16. The crucible-based continuous self-circulating gas- atomization process of claim 7, wherein, In step (5), the rotating speed of the second motor is 100-1000r / min, the transmission ratio of the second worm gear is 20:1-80:1, and the downward and upward moving speed of the sampler is 40-90mm / min.

17. The crucible-based continuous self-circulating gas- atomization process of claim 7, wherein, In step (6), the rotation speed of the first motor is 100-1000 r / min, the transmission ratio of the first worm gear is 20:1-80:1, and the moving speed of the barrel is 40-90 mm / min.

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