A control device for quickly responding to and adjusting melt flow, a control method and its application

Abstract

The present invention provides a control device, a control method and an application thereof for quickly responding and adjusting the melt flow rate, comprising: a smelting module, an atomization system and an atomization bin, the atomization system and the atomization bin are arranged below the smelting module, the atomization system is used to atomize and powder the melt, and the atomization bin is used to provide a closed environment for atomization and powdering; a monitoring system, comprising a flow sensor or a height sensor and a pressure sensor 1; a pressure sensor and exhaust system, comprising a pressure sensor 2, an exhaust passage and an exhaust fan, the pressure sensor 2 is located on the inner wall of the atomization bin or in the exhaust passage; a control system, the control system is connected to the monitoring system, the pressure sensor and the exhaust system in communication, the control system receives the monitoring data of the monitoring system, measures the pressure in the atomization bin and controls the exhaust fan power to stabilize the melt flow rate. The method can effectively control small flow rate fluctuations, improve the fine powder recovery rate of metal powders, and reduce the standard deviation of particle size distribution.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy, and in particular relates to a control device for quickly responding and adjusting melt flow, a control method and an application thereof. Background Art

[0002] Atomization refers to an industrial powder making technology that uses inert gas or high-pressure water jet as the atomizing medium, utilizes high-speed gas / water jet to impact molten metal and rapidly cool and solidify it to obtain fine metal-based powder.

[0003] During the atomized powder preparation process, due to the limitations of the pouring / bottom pouring equipment, the molten metal level above the spray plate fluctuates or decreases, causing the static pressure of the molten steel to change accordingly, making it difficult to maintain stable pouring of the molten metal, and even causing backgassing and splashing of molten steel, which seriously affects the smooth atomization and safe production.

[0004] Basic research shows that a stable mass flow rate of molten metal is beneficial to the consistency of atomized powder, and the factors directly affecting the mass flow rate of molten metal mainly include the diameter of the liquid guide tube and the atomizing gas pressure (changing the pressure distribution in the atomizing chamber). However, the diameter of the liquid guide tube cannot be changed during the production process, and adjusting the atomizing gas pressure will significantly change the flow field distribution in the atomizing chamber and produce other effects. Therefore, it is very important to quickly respond and adjust the mass flow rate of the atomized molten metal through other means during the atomization production process.

[0005] There are technical solutions in the prior art for controlling the mass flow rate of molten metal based on pressure, but there are the following problems: 1. High temperature has a great influence on the pressure sensor. The increase in temperature affects the mechanical properties of the pressure sensor diaphragm, which in turn affects the service life and measurement accuracy of the pressure sensor; 2. At the lower end of the liquid guide tube, the melt is atomized into small droplets and has not yet completely solidified. It is in a molten or semi-solidified state. At this time, the small droplets are easy to gather and adhere to the sensor, affecting the measurement accuracy of the sensor, and there are often problems such as signal loss during the production process and inaccurate melt flow control due to errors in the measurement data; 3. The control accuracy is poor. When the pressure in the smelting chamber is constant, since the pressure at the lower end of the liquid guide tube is related to the melt flow rate, the pressure at the lower end of the liquid guide tube is controlled based on the constant flow rate, so that the pressure adjustable range to achieve the target flow rate is small, and it is difficult for the control system to accurately control the power of the exhaust fan to achieve the required pressure value at the lower end of the liquid guide tube.

[0006] In summary, a method for adjusting the negative pressure in the atomization chamber in real time during the atomization production process and ensuring the stability of the mass flow rate of the molten metal has important practical significance for improving the atomization production efficiency. Summary of the invention

[0007] To solve the above problems, the present invention provides a control device, a control method and an application thereof for quickly responding to and adjusting the melt flow rate. By setting a pressure sensor at a specific position and combining it with the control method provided by the present invention, it is possible to effectively control tiny flow rate fluctuations, improve the fine powder yield of metal powder, and reduce the standard deviation of particle size distribution.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] In one aspect, the present invention provides a control device for quickly responding to and adjusting melt flow, comprising:

[0010] A smelting module, the smelting module includes a smelting chamber, and a crucible arranged in the smelting chamber, a liquid guide tube is arranged below the crucible, for conveying the melt to an atomization system and an atomization bin; an atomization system and an atomization bin, the atomization system and the atomization bin are arranged below the smelting module, the atomization system is used to atomize and powder the melt, and the atomization bin is used to provide a closed environment for atomization and powder making; a monitoring system, including a flow sensor or a height sensor and a pressure sensor 1, the flow sensor is used to detect the quality of the melt, and the height sensor is arranged in the smelting chamber to detect the height of the melt in the crucible; the pressure sensor 1 is used to measure the pressure in the smelting chamber; a pressure measuring and exhaust system, including a pressure sensor 2, an exhaust channel and an exhaust fan, the pressure sensor 2 is located on the inner wall of the atomization bin or in the exhaust channel; a control system, the control system is communicatively connected with the monitoring system, the pressure measuring and exhaust system, the control system receives monitoring data of the monitoring system, measures the pressure in the atomization bin and controls the exhaust fan power to stabilize the melt flow.

[0011] Furthermore, the height sensor is a high-speed camera or a microwave rangefinder.

[0012] Furthermore, when the second pressure sensor is located on the inner wall of the atomization chamber, the distance between the second pressure sensor and the edge of the exhaust port does not exceed 2 / 3 of the diameter of the exhaust channel.

[0013] Furthermore, the flow sensor is arranged at the lower part of the liquid guiding tube.

[0014] On the other hand, the present invention provides a control method for a control device for quickly responding to and adjusting melt flow, comprising the following steps:

[0015] S1, preliminarily construct the relationship formula between fluid flow rate, liquid level height and pressure in the atomization chamber, as well as time, exhaust fan power and pressure in the atomization chamber, and conduct cold state experiments, use pure water instead of melt to correct the coefficients in the relationship formula through multiple tests, and obtain the corrected relationship formula;

[0016] S2, conducting a hot state experiment, and performing a secondary correction on the corrected coefficient based on the hot melt to obtain a final relationship formula;

[0017] S3, using the final relationship formula to guide the above control device to perform industrial production.

[0018] Furthermore, in said S1,

[0019] The relationship between the initial fluid flow rate, liquid level and pressure in the atomization chamber is as follows:

[0020]

[0021] P3=f(x p ,x T ,P2)

[0022] Where, P1 is the surface pressure of the fluid in the smelting chamber, P2 is the pressure below the liquid guide tube, P3 is the pressure in the atomization chamber, ρ is the fluid density, g is the gravitational acceleration, and h is the pressure of the atomization chamber. a is the height of the liquid level in the crucible, h b is the length of the liquid guide tube, u is the metal liquid flow rate at the end of the liquid guide tube, α a is the correction coefficient of the kinetic energy of the fluid in the crucible, α b is the correction coefficient of the kinetic energy of the fluid in the catheter, f a is the crucible damping coefficient, f b is the damping coefficient in the catheter, λ is the local damping coefficient, D a is the equivalent diameter of the crucible, D b is the equivalent diameter of the catheter, S a is the cross-sectional area of ​​the fluid in the crucible, S b is the cross-sectional area of ​​the fluid in the catheter, du / dt is the rate of change of the fluid velocity over time, x p is the atomization pressure, x T is the atomizing medium temperature.

[0023] Furthermore, through cold experiments, α a , α b , f a , f b And the relationship between the λ coefficient and the material parameters of the inner wall of the smelting chamber, the material parameters of the liquid guide tube, the diameter of the liquid guide tube, the atomization pressure and the temperature of the atomization medium.

[0024] Furthermore, in S1, the relationship between the time, the exhaust fan power and the pressure in the atomization chamber is as follows:

[0025] P3=f(W,t,x p ,x T )

[0026] Wherein, t is the time required for the exhaust fan, and w is the exhaust fan power.

[0027] Furthermore, in S2, the secondary correction is to determine the relationship between the corrected coefficient in the cold experiment and the viscosity and superheat of the molten metal through a hot experiment.

[0028] On the other hand, according to the application of the above control method, the method is applied to a gas atomization or gas-water combined atomization process.

[0029] The beneficial effects brought by the technical solution provided by the embodiment of the present invention include: the present invention arranges the second pressure sensor on the inner wall of the atomizing chamber or in the exhaust channel. Preferably, when the second pressure sensor is located on the inner wall of the atomizing chamber, the distance between the second pressure sensor and the edge of the exhaust port does not exceed 2 / 3 of the diameter of the exhaust channel. The above two positions can solve the three technical problems involved in the background technology. Since they are far away from the metal atomizing nozzle area, most of the droplets are in a solidified state and will not adhere to the pressure measuring surface of the pressure sensor. Moreover, the temperatures of the two positions are relatively low, and it is common knowledge that the atomizing chamber wall is provided with a water cooling channel. Therefore, the pressure sensor will not be affected by the temperature. In particular, the third problem is solved. Since the flow field in the inner wall of the atomizing chamber or the exhaust channel is stable and has a similar amplification effect, that is, the pressure at the lower end of the liquid guide tube has a certain functional relationship with the pressure in the atomizing chamber wall or the exhaust channel, after amplification, it is convenient for the control system to control the exhaust system, especially for the field of 3D printing powder making, so the tiny flow rate fluctuation of the melt flow can be controlled, which can greatly reduce the fine powder recovery rate and reduce the standard deviation of the particle size distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A schematic diagram of the structure of a control device for quickly responding and adjusting melt flow rate provided in Example 1 of the present invention;

[0032] Figure 2 A curve diagram of the pressure below the liquid guide tube and the pressure adjustment value in the atomization chamber corresponding to the flow rate change provided in Example 1 of the present invention;

[0033] Figure 3 A schematic diagram of the structure of a control device for quickly responding and adjusting melt flow rate provided in Example 2 of the present invention;

[0034] Figure 4A control flow chart of a control device for quickly responding to and adjusting melt flow provided in Example 3 of the present invention;

[0035] Figure 5 The particle size distribution of powder produced under existing technical conditions;

[0036] Figure 6 The embodiment of the present invention provides the particle size distribution of powder produced by the method for adjusting the flow rate of atomized melt by rapid response provided by the present invention.

[0037] Figure numerals: 1-control device for quickly responding to and adjusting the melt flow rate; 10-smelting module; 11-smelting chamber; 12-crucible; 13-liquid guide tube; 14-melt; 21-atomization bin; 22-atomization system; 31-pressure sensor 1; 32-flow sensor; 33-height sensor; 41-pressure sensor 2; 42-exhaust channel; 43-exhaust fan; 50-control system. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0039] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0040] Example 1

[0041] The present invention provides a control device 1 for adjusting melt flow rate with rapid response, such as Figure 1 As shown, including:

[0042] The smelting module 10 includes a smelting chamber 11 and a crucible 12 disposed in the smelting chamber 11 . A liquid guide tube 13 is disposed below the crucible to transport the melt 14 to an atomization system 22 and an atomization chamber 21 .

[0043] It can be understood that the atomization system includes an atomizing spray disc, and the atomization medium can be gas or a combination of gas and water, which is suitable for a variety of processes; the above-mentioned liquid guide tube 13 can be independently arranged with the crucible 12 to facilitate subsequent replacement of the crucible or the liquid guide tube, or the liquid guide tube and the crucible can be formed in one piece.

[0044] The atomization system 22 and the atomization bin 21 are arranged below the smelting module 10 . The atomization system is used to atomize and powder the melt 14 , and the atomization bin 21 is used to provide a closed environment for atomization and powder making.

[0045] The monitoring system includes a pressure sensor 31 and a height sensor 33. The height sensor 33 is arranged in the smelting chamber to detect the height of the melt in the crucible, and the pressure sensor 1 is used to detect the pressure in the smelting chamber 11. In this embodiment, the height sensor is preferably a high-speed camera, or a microwave rangefinder or other sensor that can measure the liquid level. The relevant monitoring data is transmitted to the control system 50 in real time through the pressure sensor 31 and the height sensor 33.

[0046] Preferably, the height sensor 33 and the pressure sensor are arranged on the shell of the smelting chamber or protrude outward from the shell of the smelting chamber under the condition of satisfying the measurement accuracy, so as to avoid the influence of temperature and high-temperature flue gas on the sensor and increase the service life and measurement accuracy of the sensor. Since the height sensor 33 measures the height of the fluid level in real time, it is possible to calculate whether the falling speed of the liquid level is uniform, that is, whether the melt flow rate of the liquid guide pipe is stable. This embodiment is suitable for intermittent production mode, that is, the liquid level continues to fall during the production process.

[0047] The pressure measuring and exhaust system includes a second pressure measuring sensor 41 , an exhaust passage 42 and an exhaust fan 43 . The second pressure measuring sensor 41 is located on the inner wall of the atomizing chamber 21 or in the exhaust passage 42 .

[0048] Preferably, the distance between the pressure sensor 2 in this embodiment and the edge of the exhaust port does not exceed 2 / 3 of the diameter of the exhaust passage, or the sensor 2 is directly arranged in the exhaust passage.

[0049] The control system 50 is in communication with the monitoring system, the pressure measuring system and the exhaust system. The control system receives monitoring data from the monitoring system, measures the pressure in the atomizing bin and controls the exhaust fan power to stabilize the melt flow.

[0050] In this embodiment, the control system determines whether the melt flow is stable based on the real-time data transmitted by the height sensor. When the melt flow deviation is a certain value, the control system 50 controls the power of the exhaust fan, controls the pressure in the atomization chamber and the pressure difference in the smelting chamber, and ensures the stability of the melt flow. Specifically, when the pressure in the smelting chamber is constant, the power of the exhaust fan is directly controlled by the computer control system. By changing the power of the exhaust fan, the pressure in the atomization chamber can be adjusted, and then the mass flow rate of the molten metal can be adjusted. Among them, when the computer control system determines that the mass flow rate of the molten steel is about to exceed the preset mass flow rate fluctuation threshold range, the computer control system adjusts the pressure in the atomization chamber through the built-in adjustment program. That is, when the mass flow rate of the molten steel needs to be reduced, the power of the exhaust fan is reduced, the pressure below the liquid guide tube is increased, and the mass flow rate of the molten steel is reduced; when the mass flow rate of the molten steel needs to be increased, the power of the exhaust fan is increased, the pressure below the liquid guide tube is reduced, and the mass flow rate of the molten steel is increased. The control system 50 is provided with an automatic metal liquid flow rate adjustment program. The program is based on the inherent relationship between the mass flow rate of the metal liquid, the liquid level and the pressure below the liquid guide tube. Through the pressure and liquid level data measured at each moment in the atomization process, the program predicts the change in the mass flow rate of the metal liquid at the next moment. When it is predicted that the mass flow rate of the metal liquid is about to exceed the pressure threshold, a corresponding judgment is made and the exhaust fan power is adjusted accordingly.

[0051] This embodiment does not limit the connection method of the atomizing medium inlet of the atomizing system and the atomizing medium outlet of the exhaust fan. Usually, the exhaust fan outlet purifies the gas and then transports the atomizing medium to the atomizing medium inlet of the physical and chemical system through a delivery pipeline.

[0052] It is understandable that due to the high pressure of the atomizing medium in the atomizing system, the pressure fluctuation will lead to the disorder of the gas flow field and the atomizing effect, especially the particle size and quality of the powder. The atomizing medium pressure needs to be set to a fixed value. However, even after it is set to a fixed value, the pressure field and flow field in the atomizing bin are unevenly distributed, that is, the pressure values ​​at different positions are different. Moreover, due to the change in the flow direction of the atomizing medium at the same position, the measurement of the pressure sensor is greatly affected. In order to obtain accurate measurement data, the prior art directly sets the pressure sensor 2 at the lower end of the liquid guide tube. However, there are the following problems: 1. High temperature has a great influence on the pressure sensor. The increase in temperature affects the mechanical properties of the pressure sensor diaphragm. 1. The pressure sensor has a certain influence on the service life and measurement accuracy of the pressure measuring sensor; 2. At the lower end of the liquid guide tube, the melt is atomized into small droplets and has not yet completely solidified, and is in a molten or semi-solidified state. At this time, the small droplets are easy to gather and adhere to the sensor, affecting the measurement accuracy of the sensor, and signal loss often occurs during the production process, and the melt flow control is not accurate enough due to errors in the measurement data; 3. The control accuracy is poor. When the pressure in the smelting chamber is constant, since the pressure at the lower end of the liquid guide tube is related to the melt flow, the pressure at the lower end of the liquid guide tube is controlled based on the constant flow, so that the adjustable range of pressure to achieve the target flow is small, and it is difficult for the control system to accurately control the power of the exhaust fan to achieve the required pressure value at the lower end of the liquid guide tube. The present invention arranges the second pressure sensor on the inner wall of the atomizing chamber or in the exhaust channel. Preferably, when the second pressure sensor is located on the inner wall of the atomizing chamber, the distance between the second pressure sensor and the edge of the exhaust port does not exceed 2 / 3 of the diameter of the exhaust channel. The above two positions can solve the above three problems. Since they are far away from the metal atomizing nozzle area, most of the droplets are in a solidified state and will not adhere to the pressure measuring surface of the pressure sensor. In addition, the temperatures of the two positions are relatively low, and it is common knowledge that the atomizing chamber wall is provided with a water cooling channel. Therefore, the pressure sensor will not be affected by the temperature. In particular, the third problem is solved. Since the flow field in the inner wall of the atomizing chamber or the exhaust channel is stable and has an amplification effect, that is, the pressure at the lower end of the liquid guide tube has a certain functional relationship with the pressure in the atomizing chamber wall or the exhaust channel, after amplification, it is convenient for the control system to control the exhaust system. Especially for the field of 3D printing powder making, the slight flow rate fluctuation of the melt flow can be controlled. Figure 2 As shown in the figure, when the temperature and pressure of the atomizing medium are constant, the pressure sensor 2 is set at the upper part of the exhaust port and 2 / 3 of the exhaust channel diameter from the edge of the exhaust port. Based on the curve of the pressure below the liquid guide tube corresponding to the flow change and the pressure adjustment value in the atomization chamber, it can be seen that the pressure at the lower end of the liquid guide tube is magnified by about three times, so the small flow rate fluctuation of the melt flow can be better controlled, which can greatly improve the fine powder recovery rate and reduce the standard deviation of the particle size distribution. The airflow stability in the smelting chamber is good, so the above problem does not exist when the pressure sensor 1 is set.

[0053] Example 2

[0054] The present invention provides a control device 1 for adjusting melt flow rate with rapid response, such as Figure 3 As shown, different from the embodiment, the monitoring system in this embodiment includes a pressure sensor 31 and a flow sensor 32, and the flow sensor is used to detect the melt flow rate.

[0055] Specifically, the flow sensor 32 is arranged at the lower part of the liquid guiding tube. This embodiment is suitable for the case where the height of the melt level in the crucible is constant, so there is no need to arrange a height sensor.

[0056] The control system 50 determines whether the melt flow is stable based on the real-time data transmitted by the flow sensor 32. When the flow deviation is a certain value, the control system 50 controls the power of the exhaust fan, controls the pressure in the atomization bin and the pressure difference in the smelting chamber, and ensures the stability of the melt flow.

[0057] Example 3

[0058] The present invention provides a control method for a control device for quickly responding to and adjusting melt flow rate, such as Figure 4 As shown, including,

[0059] S1. Preliminarily construct the relationship formula between fluid flow rate, liquid level height and pressure in the atomization chamber, as well as time, exhaust fan power and pressure in the atomization chamber, and conduct cold experiments. Pure water is used instead of melt to correct the coefficients in the relationship formula through multiple tests to obtain the corrected relationship formula.

[0060] The relationship between the initial fluid flow rate, liquid level and pressure in the atomization chamber is as follows:

[0061]

[0062] P3=f(x p ,x T P2) (2)

[0063] Where, P1 is the surface pressure of the fluid in the smelting chamber, P2 is the pressure below the liquid guide tube, P3 is the pressure in the atomization chamber, specifically the pressure at a specific position of the pressure sensor set on the wall of the atomization chamber or the exhaust channel, ρ is the fluid density, g is the gravitational acceleration, h a is the height of the liquid level in the crucible, h b is the length of the catheter, u is the flow rate of the fluid at the end of the catheter, α a is the correction coefficient of the kinetic energy of the fluid in the crucible, α b is the correction coefficient of the kinetic energy of the fluid in the catheter, f a is the crucible damping coefficient, which is related to the relative roughness of the crucible, f bis the damping coefficient in the catheter, which is related to the relative roughness of the catheter, λ is the local damping coefficient, which is related to the interface structure, and D a is the equivalent diameter of the crucible, D b is the equivalent diameter of the catheter, S a is the cross-sectional area of ​​the fluid in the crucible, S b is the cross-sectional area of ​​the fluid in the catheter, du / dt is the rate of change of the fluid velocity with time, x p is the atomization pressure, x T is the atomizing medium temperature.

[0064] The relationship between P1 and P3 can be obtained by eliminating P2 through the above formulas 1 and 2.

[0065] Through cold experiments, we can determine α a , α b , f a , f b And the relationship between the λ coefficient and the material parameters of the inner wall of the smelting chamber, the material parameters of the liquid guide tube, the diameter of the liquid guide tube, the atomization pressure and the temperature of the atomization medium.

[0066] α a =f(x1,x2,x3,x p ,x T ) (3)

[0067] α b =f(x1,x2,x3,x p ,x T ) (4)

[0068] f a =f(x1,x2,x3,x p ,x T ) (5)

[0069] f b =f(x1,x2,x3,x p ,x T ) (6)

[0070] λ=f(x1,x2,x3,x p ,x T ) (7)

[0071] Among them, x1 and x2 are the material parameters of the inner wall of the melting chamber and the material parameters of the liquid guide tube, respectively. The material parameters are crucibles and liquid guide tubes made of different refractory materials, such as magnesia, clay, graphite, quartz, corundum, and ceramics; x3 is the diameter of the liquid guide tube; x p is the atomization pressure; x T is the atomizing medium temperature, specifically the atomizing pressure and the atomizing medium temperature when the atomizing medium is input into the atomizing spray disc. The above parameters are all known constants.

[0072] The relationship between the time, exhaust fan power and pressure in the atomization chamber is as follows:

[0073] P3=f(W,t,x p ,x T ) (8)

[0074] Wherein, t is the time required for the exhaust fan, and w is the exhaust fan power.

[0075] S2, conducting a hot experiment, and performing a secondary correction on the corrected coefficient based on the hot melt to obtain a final relationship formula.

[0076] The secondary correction is to determine the relationship between the corrected coefficient in the cold experiment and the viscosity of the molten metal x6 and the superheat of the molten metal x7 through a hot experiment.

[0077] α a '=f(x1,x2,x3,x p ,x T ,x6,x7) (9)

[0078] α b '=f(x1,x2,x3,x p ,x T ,x6,x7) (10)

[0079] f a '=f(x1,x2,x3,x p ,x T ,x6,x7) (11)

[0080] f b '=f(x1,x2,x3,x p ,x T ,x6,x7) (12)

[0081] λ'=f(x1,x2,x3,x p ,x T ,x6,x7) (13)

[0082] S3, using the final relationship formula to guide the control device for quickly responding and adjusting the melt flow rate in Example 1 and Example 2 to carry out industrial production.

[0083] This method is based on the inherent relationship between fluid flow rate, liquid level and pressure below the liquid guide tube. Through the pressure and liquid level data measured at each moment in the atomization process, the change in the mass flow rate of the molten metal at the next moment is predicted. When the mass flow rate of the molten metal is predicted to exceed the corresponding pressure threshold, a corresponding judgment is made and the exhaust fan power is adjusted in a targeted manner; or through the fluid flow rate measured at each moment in the atomization process, when the fluid flow rate is greater than the flow rate threshold, a corresponding judgment is made and the exhaust fan power is adjusted in a targeted manner.

[0084] For a metal powder having a liquid guide tube diameter of 0.5-3.5 mm, the metal powder obtained by applying the method for adjusting the flow rate of atomized melt by rapid response proposed in the embodiment of the present application is compared with the metal powder produced by the method disclosed in the prior art based on pressure difference control, and the particle size distribution of the produced powder is respectively as follows: Figure 5 and 6 shown. Figure 5 The particle size distribution of the powder produced under the existing technical conditions is as follows: the median particle size of the powder is 40.45 microns, the standard deviation of the particle size distribution is as high as 2.03, and the fine powder yield is only 33% (<25 microns); Figure 6 By adopting the rapid response method for adjusting the flow rate of atomized melt provided by the present invention, by stably controlling the mass flow rate of the molten metal, the median particle size of the powder is reduced to 25.56 microns, the standard deviation of the particle size distribution is reduced to 1.61, and the fine powder yield is increased to more than 50%. It can be seen that the metal powder produced by the present invention can greatly improve the quality of the metal powder, thanks to the method that can effectively control the small flow rate fluctuations.

[0085] This embodiment ultimately achieves guidance for industrial production through a combination of cold experiments and hot experiments, which can greatly reduce the number of hot experiments, reduce project R&D costs and improve the safety of the test process; secondly, based on the experience summary and implementation results in the R&D process, we obtained the above-mentioned coefficients and the parameters affecting the above-mentioned coefficients, and combined with the control device for quickly responding to adjust the melt flow rate of Examples 1 and 2, the quality of metal powder can be greatly improved.

[0086] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control device for quickly responding to and adjusting melt flow, characterized in that: include: A smelting module, the smelting module comprising a smelting chamber and a crucible arranged in the smelting chamber, a liquid guide pipe is arranged below the crucible to transport the melt to an atomization system and an atomization bin; An atomization system and an atomization bin, wherein the atomization system and the atomization bin are arranged below the smelting module, the atomization system is used to atomize and powder the melt, and the atomization bin is used to provide a closed environment for atomization and powder making; A monitoring system, comprising a flow sensor and a pressure sensor 1, or a height sensor and a pressure sensor 1; the flow sensor is used to detect the melt flow rate, the height sensor is arranged in the smelting chamber to detect the height of the melt in the crucible; the pressure sensor 1 is used to measure the pressure in the smelting chamber; A pressure measuring and exhaust system, comprising a second pressure measuring sensor, an exhaust passage and an exhaust fan, wherein the second pressure measuring sensor is located on the inner wall of the atomizing chamber or in the exhaust passage, one end of the exhaust passage is connected to the atomizing chamber through an exhaust port arranged on the side wall of the atomizing chamber, and the other end of the exhaust passage is connected to the exhaust fan; A control system is communicatively connected with the monitoring system and the pressure measuring and exhaust system, and the control system receives monitoring data from the monitoring system, measures the pressure in the atomizing bin and controls the power of the exhaust fan to stabilize the melt flow.

2. The control device according to claim 1, characterized in that: The height sensor is a high-speed camera or a microwave rangefinder.

3. The control device according to claim 1, characterized in that: When the second pressure sensor is located on the inner wall of the atomization chamber, the distance between the second pressure sensor and the edge of the exhaust port does not exceed 2 / 3 of the diameter of the exhaust channel.

4. The control device according to claim 1, characterized in that: The flow sensor is arranged at the lower part of the liquid guiding tube.

5. The control method of the control device according to any one of claims 1 to 4, characterized in that: The steps include: S1, preliminarily construct the relationship formula between fluid flow rate, liquid level height and pressure in the atomization chamber, as well as time, exhaust fan power and pressure in the atomization chamber, and conduct cold state experiments, use pure water instead of melt to correct the coefficients in the relationship formula through multiple tests, and obtain the corrected relationship formula; The relationship between the fluid flow rate, liquid level and pressure in the atomization chamber is as follows: P3=f(x p ,x T P2) Where, P1 is the surface pressure of the fluid in the smelting chamber, P2 is the pressure below the liquid guide tube, P3 is the pressure in the atomization chamber, ρ is the fluid density, g is the gravitational acceleration, and h is the pressure of the atomization chamber. a is the height of the liquid level in the crucible, h b is the length of the liquid guide tube, u is the metal liquid flow rate at the end of the liquid guide tube, α a is the correction coefficient of the kinetic energy of the fluid in the crucible, α b is the correction coefficient of the kinetic energy of the fluid in the catheter, f a is the crucible damping coefficient, f b is the damping coefficient in the catheter, λ is the local damping coefficient, D a is the equivalent diameter of the crucible, D b is the equivalent diameter of the catheter, S a is the cross-sectional area of ​​the fluid in the crucible, S b is the cross-sectional area of ​​the fluid in the catheter, du / dt is the rate of change of the fluid velocity over time, x p is the atomization pressure, x T is the atomizing medium temperature; Through cold experiments, we can determine α a , α b , f a , f b and the relationship between the λ coefficient and the material parameters of the inner wall of the smelting chamber, the material parameters of the liquid guide tube, the diameter of the liquid guide tube, the atomization pressure and the temperature of the atomization medium; The relationship between the time, exhaust fan power and pressure in the atomization chamber is as follows: P3=f(W,t,x p ,x T ) Wherein, t is the time required for the exhaust fan, and w is the exhaust fan power; S2, conduct a hot experiment, based on the hot melt, perform a secondary correction on the corrected coefficient to obtain the final relationship formula; S3, using the final relationship formula to guide the control device to perform industrial production.

6. The control method according to claim 5, characterized in that: In S2, the secondary correction is to determine the relationship between the corrected coefficient in the cold experiment and the viscosity and superheat of the molten metal through a hot experiment.

7. Application of the control method according to any one of claims 5-6, characterized in that: The method is applied to gas atomization or gas-water combined atomization process.

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