Similar experiment-based supersonic gas atomization experiment platform

Abstract

The utility model relates to the field of metal smelting and additive manufacturing, and particularly discloses a supersonic gas atomization experimental platform based on a similar experiment, which comprises experimental platform construction, system composition and a simulation method. Belongs to the field of additive manufacturing high-temperature alloy powder preparation. The supersonic gas atomization experiment platform is characterized in that the structure of each system of the supersonic gas atomization experiment platform based on similar experiment-numerical simulation is designed, and the supersonic gas atomization experiment platform comprises a smelting system, an atomization system, an external atomization gas tank, an optical observation system, a filtering and gas extracting device and corresponding electric and gas pipelines; in-situ observation of the liquid drop crushing and atomizing process of low-melting-point substances such as water and tin can be achieved, and a basis is provided for gas atomization mechanism research of additive manufacturing high-temperature alloy powder and optimization of technological parameters in the powder manufacturing process. The method is suitable for gas atomization mechanism research and process parameter optimization in the gas atomization process of most additive manufacturing high-temperature alloy powder, and has very high economic value.

Description

Technical Field

[0001] The utility model relates to the fields of metal smelting and additive manufacturing, and particularly relates to a supersonic gas atomization experimental platform based on "similar experiments". Background Art

[0002] Due to their excellent hot corrosion resistance, oxidation resistance, high-temperature stability and structural stability, superalloys are widely used in the fields of aerospace, ship engineering and special environments. With the continuous improvement of the complexity and precision of superalloy parts structures, the disadvantages of high cost, long construction period and poor quality stability of traditional casting and forging processes have been continuously magnified, seriously restricting the high-quality and high-efficiency preparation of superalloy parts. In recent years, the rapid development of additive manufacturing technology has provided a new option for the high-precision preparation and forming of complex parts. As the basic raw material for additive manufacturing, the current main preparation method of spherical powder is inert gas atomization (VIGA).

[0003] For the inert gas atomization powder preparation process, during the gas atomization process, high-speed atomization gas impacts and breaks the high-temperature molten metal stream into small-sized metal droplets, and then the droplets quickly cool and solidify into spherical particles in the atomization chamber. Previous studies have divided the entire atomization process into primary atomization and secondary atomization. Since the gas atomization process is usually complex, fast and intense; the physical and chemical processes during production change very complexly, involving the complex conversion of melt thermal energy and gas kinetic energy into the surface energy of powder particles, all containing the processes of metal melting, melt fragmentation, cooling and solidification, and the temperature field and velocity field change extremely fast. The molten alloy droplets in the atomization process are small in size and have a large number of irregular deformations, and the atomization process occurs in a closed space. In addition, primary atomization and secondary atomization almost occur simultaneously in a high-speed and high-pressure environment. Therefore, it is very difficult for conventional experimental means to accurately characterize or online monitor the actual change process. And the domestic gas atomization powder preparation technology and equipment started relatively late. Currently, production mainly relies on workers' experience, and there are problems such as relatively low fine powder recovery rate and unstable powder batches

[0004] The similarity theory means that in the same physical process, the basic parameters of the model composition are similar to the corresponding parameters of the prototype, including geometric parameters and physical parameters, and its specific manifestation is that the fields composed of a series of physical quantities correspond and are similar. Through the similarity theory, it is possible to characterize and optimize the experiments that are easy to observe or conduct, and then guide the process optimization of experiments or production processes that are difficult to directly observe. This also provides a theoretical basis for in-situ observation of the gas atomization process of low-melting-point substances such as water and tin, and then clarifying the particle fragmentation and solidification behavior and optimizing the production process conditions during the gas atomization process of metal melts

[0005] In summary, for the complex environment of multi-physical field coupling in atomization powder making, based on the simulation of the atomization process, by building a similar experimental system, the high-temperature liquid flow breakup and spheroidization behaviors in the atomization process are clarified, a new method for researching the gas atomization process based on similar experiments is formed, and the problem of the black box of atomization powder making is solved. This helps to promote the development of the gas atomization powder making process in China and has important social and economic significance for the development of the gas atomization powder making technology. Summary of the Invention

[0006] Aiming at the defects in the prior art, the utility model discloses a supersonic gas atomization experimental platform based on "similar experiments".

[0007] The technical solution of the utility model is as follows:

[0008] A supersonic gas atomization experimental platform based on "similar experiments" includes a melting system, an atomization system, an external atomizing gas tank, an optical observation system, a filtering and air extraction device, and corresponding electrical and gas pipelines that are connected from top to bottom. Its specific structure is as follows:

[0009] The melting system uses an electrically heated melting crucible with a melting insulation tank installed outside, and is also equipped with a temperature measuring device. The upper part inside the tank is connected to an internal crossbeam, and a ceramic rod and a thermocouple are connected to the crossbeam. The melting system is integrally installed on the top of the furnace body; a diversion tube channel is reserved in the center of the lower part of the melting system, and a small hole is left at the center position of the lower part of the electrically heated melting crucible for placing the diversion tube;

[0010] The atomization system includes a diversion tube, an atomizer, an atomization furnace body, a standing wave ultrasonic device, and a collection device; the atomizer is placed under the electrically heated melting crucible; the diversion tube passes through the atomization furnace body and the atomizer and then enters the upper part of the atomization furnace body. The lower area of the diversion tube is the atomization area, and standing wave ultrasonic devices are installed on both sides of the atomization furnace body at the height of the atomization area;

[0011] The external atomizing gas tank is connected to the atomizer through a pipeline, and a valve is provided on the pipeline;

[0012] The optical observation system includes a high-speed camera, a viewing window, a background light source, and a signal acquisition device. The observation window is set at the upper part of the atomization furnace body at the same height as the standing wave ultrasonic device. A background light source is provided on the other side of the furnace body opposite to the viewing window; the background light source is a light source plate that emits parallel light, and a high-speed camera is equipped outside the viewing window. The high-speed camera is connected to the signal acquisition device;

[0013] The bottom of the furnace is connected to a collection device for collecting low-melting point metal powders or liquids, etc. after atomization;

[0014] A filtering and air extraction device is provided outside the bottom of the furnace for exhausting gas from the furnace body to the outside.

[0015] Furthermore, in the above-mentioned supersonic aerosolization experimental platform based on the "similar experiment", the filtering and exhaust device includes a filter and a high-pressure vortex blower.

[0016] Furthermore, the above-mentioned supersonic atomization experimental platform based on the "similar experiment" uses a ceramic rod to support the small hole at the bottom of the electrically heated melting crucible before use.

[0017] The above-mentioned simulation method of the supersonic aerosolization experimental platform based on the "similar experiment" includes the following steps:

[0018] (1) Select the material that needs to be prepared for in-situ observation of powder, such as tin and other low-melting-point metals, water, etc., and place the guide tube from the top into the small hole at the bottom of the electrically heated melting crucible;

[0019] (2) Use a ceramic rod to support the small hole at the bottom of the electrically heated melting crucible, then load the charge into the crucible, close the furnace cover and heat it until all the charge is melted and the melt is adjusted to an appropriate temperature.

[0020] (3) As needed, turn on the switch of the external atomizing gas tank, the switch of the filter and the switch of the high-pressure vortex fan, and turn on the switch of the standing wave ultrasonic device and the switch of the background light source. Then pull out the ceramic rod at the bottom of the electrically heated melting crucible, so that the melt in the crucible passes through the guide tube and the atomizing nozzle of the atomizer, and is quickly atomized under the action of the inert gas and the standing wave ultrasound. The powder is collected in the collection device under the action of the filter and the high-pressure vortex fan.

[0021] (4) According to specific needs, a high-speed camera can record the droplet falling, breaking and spheroidizing process in real time through the visual window with the assistance of background light source at any time.

[0022] (5) When all the melt in the electrically heated melting crucible has flowed out, turn off the switch of the external atomizing gas tank. After standing for 1 to 10 minutes, turn off the high-pressure vortex blower, separate the collection device from the atomizing furnace body, take out the powder or liquid in the collection device, clean the inner wall of the atomizing furnace body, and determine whether to screen the atomized powder and perform subsequent related tests according to the test needs.

[0023] The advantages and beneficial effects of the utility model are:

[0024] The utility model can realize in-situ observation of the atomization and crushing process of liquid or low-melting-point metal, and realize real-time recording of the droplet falling, crushing and spheroidization process through a high-speed camera and background light source, which is helpful for in-depth research on the mechanism of atomization process;

[0025] The utility model can realize in-depth research and analysis on the gas atomization mechanism of high melting point metal powder by studying the atomization process of liquid or low melting point metal with similar principles, which has great scientific significance.

[0026] The utility model can realize the research on the atomization behavior of liquids or low-melting-point metals in an ultrasonic standing wave field, which is helpful for realizing the in-depth research on the atomization behavior of metal powders by the ultrasonic standing wave field and has great scientific significance. Brief Description of the Drawings

[0027] Figure 1 It is a schematic diagram of a supersonic gas atomization experimental platform based on "similar experiments";

[0028] Figure 2 It is a schematic diagram of the matching of the draft tube, atomizer, crucible, etc. of the supersonic gas atomization experimental platform based on "similar experiments"; In order to show the matching of relevant components in this schematic diagram, some components are enlarged, and the component ratio does not represent the actual situation. The shape of the atomizer channel in this schematic diagram is a schematic diagram;

[0029] In the figure: 1 - electric heating melting crucible, 2 - atomizer, 21 - metal part of the atomizer, 22 - internal gas channel of the atomizer, 3 - external atomizing gas tank, 4 - standing wave ultrasonic device, 5 - high-speed camera, 6 - viewing window, 7 - background light source, 8 - atomization furnace body, 9 - collection device, 10 - filtering and air extraction device, 11 - signal acquisition device, 12 - ceramic rod, 13 - thermocouple, 14 - melting and heat preservation tank body, 15 - draft tube, 16 - internal cross beam. Detailed Embodiment Embodiment 1

[0030] In this embodiment, a supersonic gas atomization experimental platform based on "similar experiments" includes a melting system, an atomization system, an external atomizing gas tank 3, an optical observation system, a filtering and air extraction device 10, and corresponding electrical and gas pipelines that are connected from top to bottom. Its specific structure is as follows:

[0031] The melting system uses an electric heating melting crucible 1 with a melting and heat preservation tank body 14 installed outside, and is also equipped with a temperature measuring device. The upper part inside the tank body is connected to an internal cross beam 16, and a ceramic rod 12 and a thermocouple 13 are connected to the cross beam. The melting system is integrally installed on the top of the furnace body; A draft tube channel is reserved in the center of the lower part of the melting system, and a small hole is left at the center position of the lower part of the electric heating melting crucible 1 for placing the draft tube 15;

[0032] The atomization system includes a draft tube 15, an atomizer 2, an atomization furnace body 8, a standing wave ultrasonic device 4, and a collection device 9; The atomizer 2 is placed below the electric heating melting crucible 1; The draft tube 15 passes through the atomization furnace body 8 and the atomizer 2 and then leads to the upper part of the atomization furnace body 8. The lower area of the draft tube 15 is the atomization area, and standing wave ultrasonic devices 4 are installed on both sides of the atomization furnace body 8 at the height of the atomization area;

[0033] The external atomizing gas tank 3 is connected to the atomizer 2 through a pipeline, and a valve is provided on the pipeline. Inside the atomizer, there is an atomizer metal part 21 and an internal gas passage 22 of the atomizer.

[0034] The optical observation system includes a high-speed camera 5, a viewing window 6, a background light source 7, and a signal acquisition device 11. The viewing window 6 is arranged at the upper part of the atomizing furnace body 8 and at the same height as the standing wave ultrasonic device 4. On the other side of the furnace body opposite to the viewing window 6, there is a background light source 7. The background light source 7 is a light source plate that emits parallel light. A high-speed camera 5 is equipped outside the viewing window 6, and the high-speed camera 5 is connected to the signal acquisition device 11.

[0035] The bottom of the furnace is connected to a collection device 9 for collecting low-melting-point metal powders or liquids, etc. after atomization.

[0036] A filtering and air extraction device 10 is provided outside the bottom of the furnace. The filtering and air extraction device 10 includes a filter and a high-pressure vortex blower for exhausting air from inside the furnace to the outside.

[0037] Select the low-melting-point metal tin as the atomizing material, and use the supersonic gas atomization experimental platform based on "similar experiments" for in-situ observation of atomization. The usage method includes the following steps:

[0038] (1) Select 3 kg of low-melting-point metal tin for in-situ observation of powder preparation. Place the diversion tube 15 into the small hole at the bottom of the electric heating melting crucible 1 from the upper part. The inner diameter of the diversion tube 15 is 10 mm, and the length is 45 mm.

[0039] (2) Use the ceramic rod 12 to hold against the small hole at the bottom of the electric heating melting crucible 1, then load the furnace charge into the crucible, close the furnace lid and heat it until all the furnace charge melts and adjust the melt to 350 °C.

[0040] (3) Turn on the switch of the external atomizing gas tank 3, the switch of the filter and the high-pressure vortex blower. Select the atomizing gas pressure to be 2.5 MPa. Turn on the switch of the standing wave ultrasonic device 4 and the switch of the background light source 7. The ultrasonic frequency of the standing wave ultrasonic device 4 is 20 kHz. Then pull out the ceramic rod 12 at the bottom of the electric heating melting crucible 1, so that the melt in the electric heating melting crucible 1 passes through the diversion tube 15 and the atomizing nozzle of the atomizer 2, and is quickly atomized under the action of the inert gas and the standing wave ultrasonic wave. And the powder is collected in the collection device 9 under the action of the filter and the high-pressure vortex blower.

[0041] (4) Use the high-speed camera 5 to record the process of droplet falling, breaking and spheroidizing in real time through the viewing window 6 with the assistance of the background light source 7.

[0042] (5) After all the melt in the electric heating melting crucible 1 has flowed out, turn off the switch of the external atomizing gas tank 3. After standing for a period of time, 5 minutes, turn off the high-pressure vortex blower, separate the collection device 9 from the atomizing furnace body 8, and take out the powder or liquid in the collection device 9. Clean the inner wall of the atomizing furnace body, and determine whether to screen the atomized powder and conduct subsequent relevant tests according to the test requirements.

Claims

1. A supersonic atomization experimental platform based on "similar experiment", characterized in that: It includes a smelting system, an atomization system, an external atomization gas tank, an optical observation system, a filter and exhaust device, and corresponding electrical and gas pipelines connected from top to bottom. Its specific structure is as follows: The smelting system adopts an electrically heated smelting crucible with a smelting insulation tank installed on the outside, and is equipped with a temperature measuring device. The upper part of the tank is connected to an internal crossbeam, and a ceramic rod and a thermocouple are connected to the crossbeam. The smelting system is installed on the top of the furnace body as a whole; a guide pipe channel is reserved at the center of the lower part of the smelting system, and a small hole is reserved at the center of the lower part of the electrically heated smelting crucible for placing the guide pipe; The atomization system comprises a guide tube, an atomizer, an atomization furnace body, a standing wave ultrasonic device and a collecting device; the atomizer is placed at the lower part of the electrically heated smelting crucible; the guide tube passes through the atomization furnace body and the atomizer and then enters the upper part of the atomization furnace body, the lower area of ​​the guide tube is the atomization zone, and the standing wave ultrasonic devices are installed on both sides of the atomization furnace body at the height of the atomization zone; The external atomizing gas tank is connected to the atomizer through a pipeline, and a valve is provided on the pipeline; The optical observation system includes a high-speed camera, a visual window, a background light source and a signal acquisition device. The observation window is arranged at the upper part of the atomizing furnace body and is arranged at the same height as the standing wave ultrasonic device. A background light source is arranged on the other side of the furnace body opposite to the visual window. The background light source is a light source board emitting parallel light. A high-speed camera is arranged outside the visual window, and the high-speed camera is connected to the signal acquisition device. The furnace bottom is connected to a collecting device, and a filtering and exhausting device is arranged on the outer side of the furnace bottom.

2. A supersonic atomization experimental platform based on "similar experiment" according to claim 1, characterized in that: The filtering and exhausting device comprises a filter and a high-pressure vortex blower.

3. A supersonic atomization experimental platform based on "similar experiment" according to claim 1, characterized in that: Before use, use a ceramic rod to support the small hole at the bottom of the electric heating melting crucible.

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