Method for preventing gas atomization nozzle from being blocked by optimizing coupling relation between atomization pressure and flow guide pipe structure

Abstract

The invention discloses a method for preventing a gas atomization nozzle from being blocked by optimizing the coupling relation between atomization pressure and a flow guide pipe structure, efficient and continuous atomization is achieved by matching the pore diameter (3-6 mm) of a flow guide pipe, the shrinkage angle (30-60 degrees), the tail end platform width (smaller than or equal to 1 mm) and the atomization pressure (2.5-4.5 MPa) and combining a high-heat-resistant ceramic material (ZrO2 / SiC) and technological parameter optimization (GMR = 1.5-1.7, and the melt temperature is 1500-1650 DEG C). According to the method, the nozzle blocking risk is remarkably reduced, the powder D50 is 21-25 microns, the satellite powder proportion is smaller than or equal to 5%, the equipment maintenance cost is reduced by 20%, and the method is suitable for industrial production of high-precision metal powder.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas atomization powder making, and specifically relates to a method for preventing nozzle clogging by optimizing the coupling relationship between atomization pressure and a guide tube structure. The method is suitable for vacuum induction melting gas atomization (VIGA) and similar atomization processes, and can significantly improve the continuity and quality of metal powder preparation. Background Art

[0002] Gas atomization technology is the core process for preparing metal powders with high sphericity and narrow particle size distribution, and is widely used in additive manufacturing, powder metallurgy and other fields. As a key component of gas atomization equipment, the matching of the guide tube structure and the atomization pressure of the tightly coupled nozzle directly affects the atomization efficiency and nozzle life. In the prior art, the unreasonable design of the guide tube aperture and the contraction angle, coupled with the improper selection of the atomization pressure, leads to the following problems: the metal melt is retained or refluxed at the end of the guide tube, forming a solidification layer and blocking the nozzle; when the high-pressure gas interacts with the melt, the local high temperature causes the erosion of the spray disc material; the atomization pressure does not match the guide tube structure, resulting in an imbalance in the gas-liquid ratio (GMR), a wide powder size distribution, and a large number of satellite powders. Existing research mostly focuses on the optimization of a single parameter (such as the guide tube aperture or gas pressure), and lacks a systematic study of the coupling relationship between the two. For example, when the aperture of the guide tube is 4mm, if the atomization pressure is lower than 3.5MPa, it is easy to cause blockage due to backflow in the negative pressure area; and when the aperture is 5mm, if the pressure is too high, the air flow disturbance will be aggravated and the powder particle size will be coarsened. Therefore, a method for comprehensively optimizing the atomization pressure and the guide tube structure is urgently needed to achieve efficient and continuous atomization. Summary of the invention

[0003] In view of the above-mentioned deficiencies of the prior art, the present invention proposes a method for optimizing the atomization pressure and the structural parameters of the guide tube (aperture, contraction angle, material) by coupling to solve the nozzle clogging problem and improve the atomization continuity and powder quality. The method is verified by numerical simulation (such as VOF multiphase flow model, LES large eddy simulation) and industrial experiments.

[0004] The present invention is implemented as follows: a method for optimizing the coupling relationship between atomization pressure and guide tube structure to prevent aerosol nozzle clogging, wherein the guide tube has an aperture of 3-6 mm, a contraction angle of 30-60°, and a small platform width of ≤1 mm at the end;

[0005] The atomization pressure is matched according to the aperture of the guide tube: when the aperture is 4mm, the pressure is 3.5-4.5MPa, and when the aperture is 5mm, the pressure is 2.5-4.5MPa;

[0006] The guide tube is made of ZrO2 or SiC ceramics, with a temperature resistance of ≥2000℃.

[0007] The method according to claim 1 is characterized in that the gas-liquid ratio (GMR) is 1.5-1.7, the melt temperature is 1500-1650°C, and the vacuum degree is ≤5×10-3Pa.

[0008] Furthermore, the height of the contraction section of the guide tube is 2-6 mm, and the contraction angle is preferably 40-45°.

[0009] Furthermore, the inner wall of the flow guide tube is provided with a micro-groove structure to enhance the stability of liquid flow, reduce the agglomeration of metal droplets, and improve the atomization efficiency.

[0010] Furthermore, the arrangement of the air outlets of the spray plate adopts a circular symmetrical structure, so that the high-speed airflow forms a stable pulse airflow in the gas resonance chamber, thereby improving the uniformity of the metal liquid atomization.

[0011] Furthermore, a replaceable cooling protection layer is provided on the outside of the flow guide pipe to reduce the thermal shock of the high temperature environment on the flow guide pipe and increase the service life of the flow guide pipe.

[0012] Furthermore, a precision sealing structure is provided between the spray disc upper cover and the spray disc base to reduce gas leakage, improve atomization efficiency, and reduce energy consumption.

[0013] Furthermore, the air flow velocity at the outlet of the spray plate is not less than 500m / s, and the angle between the air flow velocity and the axis of the molten metal outlet of the guide tube is 10-20°, so as to optimize the gas-liquid interaction and improve the sphericity and particle size uniformity of the powder.

[0014] In the process of metal powder atomization in the prior art, the traditional nozzle structure often has problems such as unstable metal liquid flow, droplet agglomeration, uneven powder particle size distribution, and easy nozzle clogging, which seriously affect the yield and sphericity of the powder, and thus reduce the material performance in high-end manufacturing fields such as additive manufacturing and powder metallurgy. In particular, in the atomization preparation process of high-temperature alloys such as high entropy alloys and titanium alloys, due to the high viscosity of the metal liquid, it is difficult for the traditional nozzle structure to accurately control the liquid flow, resulting in a wide distribution of powder particle size and low yield. In addition, the guide tube structure of the traditional gas atomization nozzle has not been fully optimized, which easily leads to the non-uniformity of the gas-liquid flow field, reduces the atomization efficiency, and increases the industrial production cost. In response to these technical bottlenecks, the present invention significantly improves the stability and efficiency of the metal atomization process by optimizing the coupling relationship between the gas atomization spray disc and the guide tube.

[0015] The present invention optimizes the structural parameters of the flow guide tube, including the aperture range, contraction angle, width of the small platform at the end of the flow guide tube, and matching atomization pressure control, so that the flow of the molten metal is more stable before entering the atomization zone, thereby avoiding premature breakage or aggregation of droplets and improving the consistency of powder particle size. At the same time, the present invention selects high-temperature resistant ceramic materials (ZrO2 or SiC) as the material of the flow guide tube to significantly improve the heat shock resistance and reduce structural damage or blockage of the flow guide tube caused by high temperature environment, thereby extending the service life of the nozzle. In addition, the present invention optimizes the airflow path of the spray disc to form an efficient resonant cavity structure, so that the atomizing airflow maintains a stable pulse mode during high-speed injection, thereby improving the uniformity of the molten metal atomization and further improving the sphericity of the powder.

[0016] The technical solution of the present invention has achieved remarkable technological progress in industrial applications, especially in the field of preparation of high-end metal powders, solving the problems of irregular powder morphology, low atomization efficiency, and uneven powder particle size distribution existing in traditional nozzles. After adopting the tightly coupled nozzle structure of the present invention, the sphericity of the powder can be increased to more than 90%, and the particle size distribution is more uniform, which effectively reduces the generation of satellite particles and hollow powders, and greatly improves the fluidity and filling density of the powder. Compared with traditional technologies, the present invention can significantly improve the yield of atomized metal powders and reduce the loss of powders during the screening process, thereby improving the economic benefits and production efficiency of materials. In addition, the technical solution of the present invention is suitable for the atomization preparation of a variety of high-performance metal materials such as high entropy alloys, titanium alloys, and stainless steel, providing a better choice of raw materials for industries such as aerospace, additive manufacturing (3D printing), powder metallurgy, and precision casting.

[0017] In summary, the present invention improves the stability of the metal liquid flow and enhances the energy utilization rate of the atomizing airflow by optimizing the nozzle structure design, thereby improving the quality and production efficiency of the powder. Compared with the prior art, the atomization method of the present invention can achieve more precise gas-liquid ratio control, ensure uniform powder morphology, and enhance the application value of powder in the fields of additive manufacturing and powder metallurgy. In addition, by adopting high-temperature resistant ceramic materials and replaceable cooling protective layers, the present invention effectively reduces nozzle loss and improves the stability and sustainability of industrial production. Therefore, this technical solution not only has broad application prospects in the field of basic material preparation, but also provides strong support for material innovation in the high-end manufacturing industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 : Schematic diagram of the optimized guide tube structure;

[0019] Figure 2 : Comparison of gas flow field simulation under different atomization pressures (3.5MPa and 4.5MPa);

[0020] Figure 3 : Example 1 (D = 4mm, P = 3.5MPa) SEM photo of nickel-based powder;

[0021] Figure 4 : Comparative Example 1 (D = 4mm, P = 2.5MPa) nozzle blockage scene picture;

[0022] Figure 5 : Comparison of powder particle size distribution curves under different parameter combinations. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0024] The technical solution of the present invention includes the optimized design of the guide tube structure, the atomization pressure matching rule and the coordinated control of the process parameters. The specific implementation steps are as follows:

[0025] 1. Optimization design of flow guide pipe structure

[0026] (1) Geometric parameters (see Figure 1 ):

[0027] Aperture (D): 3–6mm, preferably 4mm or 5mm. D=4mm: suitable for high-precision powders (D50<25μm), requiring high pressure (P=3.5–4.5MPa); D=5mm: suitable for medium-sized powders (D50=25–30μm), pressure range P=2.5–4.5MPa. Contraction angle (θ): 30°–60°, preferably 40°–45°. When θ<40°, the melt coverage area is insufficient, and when θ>45°, the air flow disturbance is aggravated. Contraction section height (H): 2–6mm, H and θ satisfy the relationship: H=D·tan(θ / 2), ensuring uniform distribution of the melt. Width of the small platform at the end (W): ≤1mm, the W accuracy is controlled by laser processing to ±0.1mm to reduce the melt retention area.

[0028] (2) Material selection:

[0029] ZrO2 ceramics: temperature resistance 2200℃, thermal conductivity 25W / (m·K), suitable for nickel-based high-temperature alloys; SiC ceramics: temperature resistance 2000℃, thermal conductivity 20W / (m·K), suitable for iron-based alloys.

[0030] 2. Atomization pressure matching rules

[0031] (1) Pressure aperture matching table:

[0032]

[0033] (2) Pressure regulation mechanism:

[0034] Low pressure protection: When P<3.5MPa (D=4mm) or P<2.5MPa (D=5mm), the alarm is automatically triggered and the pressure is increased; High pressure flow limiting: When P>4.5MPa, the pressure is limited by the gas flow valve to prevent airflow disturbance.

[0035] 3. Collaborative control of process parameters

[0036] (1) Gas-liquid ratio (GMR): 1.5–1.7, GMR < 1.5: insufficient gas kinetic energy, insufficient melt crushing, satellite powder ratio > 10%; GMR > 1.7: gas consumption increases by 20%, and powder particle size distribution becomes wider.

[0037] (2) Melt temperature control: 1500–1650°C.

[0038] (3) Vacuum system: vacuum degree ≤5×10-3Pa, to reduce oxidation inclusions.

[0039] Beneficial effects: Anti-blocking: By optimizing the contraction angle (40-45°) and controlling the width of the terminal platform (≤1mm), melt retention is reduced and the formation of a solidified layer is avoided; Efficient atomization: The atomization pressure matches the aperture of the guide tube to enhance the strength of gas-liquid interaction, powder D50 = 21-25μm, satellite powder ratio ≤5%; Long life: The ceramic guide tube is resistant to high temperature corrosion, continuous atomization time ≥8 hours, and maintenance costs are reduced by 20%; Energy saving and consumption reduction: Optimizing the gas-liquid ratio, gas consumption is reduced by 15-20%. While obtaining a higher fine powder yield, the probability of nozzle blockage is reduced, ensuring the continuity and stability of the atomization powder making process, thereby improving economic benefits.

[0040] Nozzle clogging mechanism: When the diameter of the guide tube (D) does not match the atomization pressure (P), the melt is retained at the small platform (width W) at the end of the guide tube to form a solidification layer; under low pressure (P<3.5MPa), the negative pressure area of ​​the airflow triggers melt reflux, resulting in nozzle clogging; under high pressure (P>4.5MPa), the airflow disturbance intensifies, the melt cools prematurely, and the outlet of the guide tube is blocked; structural pressure coupling relationship: the contraction angle of the guide tube (θ) affects the interaction area between the airflow and the melt. When θ=40°–45°, the airflow covers the melt surface optimally to avoid local overheating; matching rules of aperture D and pressure P: D=4mm: P≥3.5MPa is required to eliminate the negative pressure area ( Figure 2 Simulation shows that the negative pressure zone disappears when P = 3.5MPa); D = 5mm: P ≥ 2.5MPa, but P ≤ 4.5MPa must be controlled to prevent high-pressure disturbance from causing powder coarsening (D50> 30μm); Material high temperature resistance: The guide tube is made of ZrO2 / SiC ceramic (temperature resistance ≥ 2000℃, thermal conductivity ≤ 30W / (m·K)), which reduces melt solidification by reducing heat conduction and extends the service life to ≥ 8 hours.

[0041] See also Figure 1 , Figure 1 A structural schematic diagram of a tightly coupled nozzle structure provided by the present invention, as shown in the figure, comprises an atomizing spray disc 10 and a guide tube 20 tightly coupled with the atomizing spray disc 10, the atomizing spray disc 10 is composed of a coaxial spray disc upper cover 1 and a spray disc base 2, the spray disc upper cover 1 and the spray disc base 2 are combined and sealed to form a gas resonance chamber 5 and a spray disc air outlet 6; a center hole penetrating the thickness of the spray disc upper cover is provided at the center position of the spray disc upper cover 1, the guide tube 20 is inserted into the center hole and forms a tightly coupled assembly structure with the atomizing spray disc 10; the width of the small platform at the end of the guide tube is 8, the inner core 3 of the guide tube 20 is the inner diameter of the guide tube, and the outside is an integrally formed cylindrical section 4 and a contraction section 7, the upper end of the cylindrical section 4 is the molten metal inlet, and the end of the contraction section 7 is the molten metal outlet; the contraction angle of the contraction section 7 of the guide tube is 30-60°.

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme of the present invention will be clearly and completely described in combination with the embodiments below. The following embodiments and comparative examples all use vacuum induction melting gas atomization (VIGA) equipment, the vacuum degree of the equipment is ≤5×10-3Pa, the atomizing gas is argon or nitrogen, and the gas flow rate is ≥500m / s.

[0043] The present invention provides a tightly coupled nozzle structure, which realizes a more efficient atomization process by optimizing the structural design of the atomizing spray disc and the guide tube. During operation, the molten metal first flows in from the molten metal inlet of the guide tube 20, and falls steadily along the inner wall of the guide tube. Since the inner core 3 of the guide tube 20 is designed to be a specific diameter, and the outer part adopts an integrally formed cylindrical section 4 and a contraction section 7, the molten metal flows evenly under the action of gravity and is accelerated in the contraction section 7, ensuring that the liquid flow remains in a good flow state before reaching the spray disc outlet 6. The contraction angle of the contraction section 7 is set at 30-60°, which can effectively control the speed and flow direction of the molten metal, and provide optimized initial conditions for subsequent atomization.

[0044] When the molten metal reaches the end of the constriction section 7 of the guide tube, that is, after the molten metal outlet, it enters the central area of ​​the gas atomization spray disc 10. At this time, high-speed gas (argon or nitrogen) is ejected from the spray disc outlet 6 and forms a high-frequency oscillating airflow in the gas resonance chamber 5. This structural design can enhance the impact strength of the gas, so that the airflow can act on the molten metal with higher kinetic energy, thereby improving the atomization efficiency. Due to the resonance cavity structure formed by the spray disc upper cover 1 and the spray disc base 2, the stability of the gas jet can be further enhanced, the interference of turbulence can be reduced, and the metal droplets can be more evenly broken into fine powder.

[0045] During the atomization process, the high-speed airflow interacts with the molten metal at a speed of ≥500m / s. Under the action of the kinetic energy of the gas, the molten metal is subjected to strong shearing and crushing forces, causing it to quickly split into fine droplets. These droplets are rapidly cooled and solidified into spherical or nearly spherical powders in a high vacuum environment (≤5×10-3Pa). The tight coupling design of the gas atomization spray disc 10 ensures efficient contact between the molten metal and the airflow during the atomization process, avoids the problem of irregular particle morphology caused by liquid reflux or airflow disturbance, and improves the recovery rate and sphericity of the powder.

[0046] Finally, the atomized metal powder settles under the action of gravity and is screened by a graded collection system. Due to the tightly coupled nozzle structure adopted in the present invention, the flow of molten metal is more stable, avoiding the problems of droplet agglomeration and uneven powder particle size distribution common in traditional nozzle design. Therefore, this technical solution can significantly improve the quality of atomized metal powder, enhance the fluidity and filling density of the powder, and is particularly suitable for the preparation of high-performance metal powder materials, such as aerospace, additive manufacturing (3D printing) and high-end powder metallurgy.

[0047] Example 1

[0048] This embodiment optimizes the coupling relationship between the atomization pressure and the guide tube structure, improves the inner diameter of the guide tube, and reduces the probability of the spray disc burning during the gas atomization process.

[0049] The gas atomization device provided in this embodiment adopts an annular gap nozzle, the gas flow channel of the spray plate is designed as a Laval structure, the inner diameter of the guide tube is 4mm, the contraction angle at the end of the guide tube is 40°, the contraction section height of the guide tube is 4mm, the width of the small platform of the guide tube is 0.8mm, and the guide tube is made of ZrO2 ceramic, with a temperature resistance of 2200°C and a thermal conductivity of 25W / (m·K). The gas atomization pressure is 3.5MPa, the melt temperature is 1600°C, and the gas-liquid ratio (GMR) is 1.6.

[0050] The alloy is heated to 1600℃ in a crucible to form a uniform melt. The melt is introduced into the draft tube through the tundish at a flow rate of 2m / s. The atomization system is started, and the argon pressure is adjusted to 3.5MPa and the gas flow rate is 800m 3 / h; the melt interacts with the supersonic airflow at the end of the guide tube and breaks into tiny droplets, which form spherical powder after cooling; the powder is collected in a powder collecting tank and screened and tested.

[0051] The results of Example 1 show that the atomization process is continuous and the atomization is continuous for 8 hours without nozzle blockage or spray plate burnout. The prepared alloy powder is as follows Figure 3 As shown, particle size distribution: D50 = 23μm, D90 = 45μm, sphericity: >95%; satellite powder ratio: <3%; fluidity: Hall flow rate is 15s / 50g. It has good fluidity.

[0052] Example 2

[0053] The gas atomization device provided in this embodiment adopts an annular gap nozzle, the gas flow channel of the spray plate is designed as a Laval structure, the inner diameter of the guide tube is 5mm, the contraction angle at the end of the guide tube is 45°, the contraction section height of the guide tube is 5mm, the width of the small platform of the guide tube is 0.5mm, and the guide tube is made of SiC ceramic, with a temperature resistance of 2200°C and a thermal conductivity of 20W / (m·K). The gas atomization pressure is 4.5MPa, the melt temperature is 1550°C, and the gas-liquid ratio (GMR) is 1.7.

[0054] The alloy is heated to 1550℃ in a crucible to form a uniform melt; the melt is introduced into the draft tube through the tundish at a flow rate of 1.8m / s; the atomization system is started, and the argon pressure is adjusted to 4.5MPa and the gas flow rate is 1000m 3 / h; the melt interacts with the supersonic airflow at the end of the guide tube and breaks into tiny droplets, which form spherical powder after cooling; the powder is collected in a powder collecting tank and screened and tested.

[0055] The results of Example 2 show that the gas atomization process is continuous, and the continuous atomization lasts for 10 hours without nozzle blockage or spray plate burning. The prepared alloy powder particle size distribution is: D50 = 25μm, D90 = 50μm, sphericity: > 96%; satellite powder ratio: < 4%; fluidity: Hall flow rate is 14s / 50g. It has good fluidity.

[0056] Comparative Example 1

[0057] The gas atomization device provided in this embodiment adopts an annular gap nozzle, the gas flow channel of the spray plate is designed as a Laval structure, the inner diameter of the guide tube is 4mm, the contraction angle at the end of the guide tube is 30°, the contraction section height of the guide tube is 4mm, the width of the small platform of the guide tube is 1.5mm, and the guide tube is made of ZrO2 ceramic. The gas atomization pressure is 2.5MPa, the melt temperature is 1600℃, and the gas-liquid ratio (GMR) is 1.6.

[0058] The alloy is heated to 1600℃ in a crucible to form a uniform melt; the melt is introduced into the draft tube through the tundish at a flow rate of 2m / s; the atomization system is started, and the argon pressure is adjusted to 2.5MPa and the gas flow rate is 600m 3 / h; observe the atomization process and record the blockage time.

[0059] The results of comparative example 1 show that after 5 minutes of atomization, a solidified layer is formed on the small platform at the end of the guide tube, and the nozzle is completely blocked. Figure 4 shown.

[0060] By comparing the examples with the comparative examples, it can be seen that the present invention significantly reduces the risk of nozzle clogging and improves the powder quality and atomization efficiency by optimizing the coupling relationship between the guide tube structural parameters (aperture, contraction angle, small platform width) and the atomization pressure. In Examples 1 and 2, the powder D50 is <25μm, the satellite powder ratio is <5%, and the atomization time is ≥8 hours; while in Comparative Example 1, the nozzle is blocked or the powder quality decreases, which verifies the effectiveness and necessity of the optimized design of the present invention.

[0061] Example 3: Closely coupled nozzle atomization process for the preparation of high purity titanium alloy powder

[0062] This example uses the close-coupled nozzle structure of the present invention to prepare high-purity Ti6Al4V alloy powder in a vacuum induction melting gas atomization (VIGA) device. The experimental parameters are as follows:

[0063] Equipment vacuum degree: ≤5×10-3Pa

[0064] Melting temperature: 1750℃

[0065] Atomizing gas: high purity argon (99.999%)

[0066] Gas flow rate: 600m / s

[0067] Guide tube contraction angle: 45°

[0068] Spray plate outlet diameter: 2.5mm

[0069] Experimental process:

[0070] Ti6Al4V alloy is melted to 1750℃ in a vacuum environment and flows evenly into the center area of ​​the spray disc through the guide tube 20. Under the acceleration of the contraction section 7, the molten metal enters the atomization area at a stable speed. High-speed argon gas is ejected from the spray disc outlet 6, and a stable high-frequency pulse gas flow is formed under the action of the gas resonance chamber 5 to atomize the molten metal. The optimized nozzle design allows the metal droplets to be evenly split and quickly cooled to form spherical powder.

[0071] Example 4: Closely coupled nozzle atomization process for high entropy alloy powder preparation

[0072] This example uses the tightly coupled nozzle structure of the present invention to prepare CoCrFeNiMn high entropy alloy powder for application in the field of powder metallurgy and laser cladding. The experimental parameters are as follows:

[0073] Equipment vacuum degree: ≤5×10-3Pa

[0074] Melting temperature: 1650℃

[0075] Atomizing gas: high purity nitrogen (99.999%)

[0076] Gas flow rate: 550m / s

[0077] Draft tube contraction angle: 50°

[0078] Spray plate outlet diameter: 3mm

[0079] Experimental process:

[0080] After the CoCrFeNiMn alloy is melted to 1650°C, it stably enters the atomization area through the guide tube 20. Due to the special angle design of the guide tube contraction section 7, the molten metal flows more evenly after entering the gas atomization spray disc 10, avoiding the phenomenon of droplet agglomeration. High-speed nitrogen is sprayed from the spray disc outlet 6, interacting with the molten metal, so that it is fully broken under the action of the pulse airflow of the gas resonance chamber 5 to form a uniform powder.

[0081] The tightly coupled nozzle structure of the present invention successfully solves the problems of uneven droplet distribution, irregular particle morphology, high powder oxygen content, etc. existing in traditional atomizing nozzles. It is suitable for the preparation of high-performance metal powders, especially in the fields of aerospace, powder metallurgy and additive manufacturing.

[0082] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for preventing aerosol nozzle blockage by optimizing the coupling relationship between atomization pressure and guide tube structure, characterized in that: The diameter of the guide tube is 3-6mm, the contraction angle is 30-60°, and the width of the small platform at the end is ≤1mm; The atomization pressure is matched according to the aperture of the guide tube: when the aperture is 4mm, the pressure is 3.5-4.5MPa, and when the aperture is 5mm, the pressure is 2.5-4.5MPa; The guide tube is made of ZrO2 or SiC ceramics, with a temperature resistance of ≥2000℃.

2. The method according to claim 1, characterized in that: The gas-liquid ratio (GMR) is 1.5-1.7, the melt temperature is 1500-1650°C, and the vacuum degree is ≤5×10-3Pa.

3. The method according to claim 1, characterized in that: The height of the contraction section of the guide tube is 2-6 mm, and the contraction angle is preferably 40-45°.

4. The method according to claim 1, characterized in that: The inner wall of the flow guide tube is provided with a micro-groove structure to enhance the stability of liquid flow, reduce the agglomeration of metal droplets, and improve the atomization efficiency.

5. The method according to claim 1, characterized in that: The arrangement of the nozzle outlet adopts a circular symmetrical structure, so that the high-speed airflow forms a stable pulse airflow in the gas resonance chamber, improving the uniformity of the metal liquid atomization.

6. The method according to claim 1, characterized in that: A replaceable cooling protection layer is provided on the outside of the guide tube to reduce the thermal shock of the high temperature environment on the guide tube and increase the service life of the guide tube.

7. The method according to claim 1, characterized in that: A precision sealing structure is provided between the spray plate upper cover and the spray plate base to reduce gas leakage, improve atomization efficiency, and reduce energy consumption.

8. The method according to claim 1, characterized in that: The air flow velocity at the nozzle plate outlet is not less than 500m / s, and the included angle with the axis of the molten metal outlet of the guide tube is 10-20°, so as to optimize the gas-liquid interaction and improve the sphericity and particle size uniformity of the powder.

Images