A tight coupling nozzle structure and an aerosol device

Abstract

The present application relates to the technical field of gas atomization device, and discloses a tight coupling nozzle structure and a gas atomization device, the tight coupling nozzle structure comprises a gas atomization nozzle disc and a flow guide pipe, the gas atomization nozzle disc is composed of a coaxial nozzle disc upper cover and a nozzle disc base, the flow guide pipe is inserted into the center hole of the thickness of the nozzle disc upper cover and forms a tight coupling assembly structure with the gas atomization nozzle disc, the vertical spacing between the nozzle disc gas outlet and the outer wall of the flow guide pipe is equal to the bottom ring thickness of the nozzle disc upper cover, the bottom ring thickness of the nozzle disc upper cover is 1-2 mm, the inner core of the flow guide pipe is a cylindrical hole, the outside is an integrally formed cylindrical section and a contraction section, and the contraction angle of the flow guide pipe contraction section is 30-60 degrees, the present application optimizes the contraction angle of the flow guide pipe contraction section and the bottom ring thickness of the nozzle disc upper cover, reasonably controls the position of the atomization backflow area, obtains higher fine powder yield, and reduces the probability of nozzle blockage.

Description

Technical Field

[0001] This invention belongs to the technical field of gas atomization devices, and specifically relates to a tightly coupled nozzle structure and a gas atomization device. Background Technology

[0002] In recent years, with the rapid development of technologies such as powder metallurgy, 3D printing, and injection molding, higher requirements have been placed on the quality of the prepared metal powders. Existing technologies not only require metal powders to have ultra-cleanliness, small particle size, and narrow distribution, but also require the prepared metal powders to have high sphericity and flowability in order to further improve the relative density and physical properties of the molded parts.

[0003] Different gas atomization process parameters have varying effects on powder particle size, satellite powder content, and powder performance. Gas atomization powder production equipment typically features a tightly coupled nozzle (the nozzle structure includes a spray disc and a melt guide tube). The molten metal flows out through the guide tube and interacts with the high-pressure atomizing gas. The characteristic of the tightly coupled nozzle is the small horizontal distance between the spray disc outlet and the end of the guide tube, which significantly increases the interaction intensity between the atomizing gas and the molten metal. This enhances the effect of the atomizing gas on the molten metal flow and reduces atomizing gas consumption.

[0004] However, the distance between the air outlet of the spray disc and the guide tube affects the efficiency of the air atomization process. If the distance is too large, the prepared powder particle size is coarser; if the distance is too small, the guide tube is easily blocked or the spray disc is burned out, seriously affecting the smooth operation of industrial air atomization production. Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a tightly coupled nozzle structure and an air atomizing device, which aims to solve the problem that the existing air atomizing device is prone to blockage of the guide tube or burn-out of the spray disc during the powder making process.

[0006] The technical solution of the present invention is as follows:

[0007] A tightly coupled nozzle structure includes an atomizing spray disc and a guide tube tightly coupled to the atomizing spray disc. The atomizing spray disc consists of a coaxial spray disc cover and a spray disc base. After the spray disc cover and the spray disc base are sealed together, they form a gas resonance chamber and a spray disc outlet. A central hole penetrating the thickness of the spray disc cover is provided at the center of the spray disc cover. The guide tube is inserted into the central hole and forms a tightly coupled assembly structure with the atomizing spray disc. The vertical distance between the spray disc outlet and the outer wall of the guide tube is equal to the thickness of the bottom ring of the spray disc cover, and the thickness of the bottom ring of the spray disc cover is 1-2 mm. The inner core of the guide tube is a cylindrical hole, and the outer part consists of an integrally formed cylindrical section and a contraction section. The upper end of the cylindrical section is a molten metal inlet, and the end of the contraction section is a molten metal outlet. The contraction angle of the contraction section of the guide tube is 30-60°.

[0008] In the tightly coupled nozzle structure, the inner core diameter of the guide tube is 3-6 mm.

[0009] In the tightly coupled nozzle structure, the cylindrical section of the guide tube has a height of 8-15mm, and the converging section has a height of 2-6mm.

[0010] The tightly coupled nozzle structure, wherein the flow channel of the gas resonance chamber is designed as a Laval structure or a tapered structure.

[0011] In the tightly coupled nozzle structure, the guide tube is made of ZrO2 ceramic material or SiC ceramic material.

[0012] An atomizing device, comprising the tightly coupled nozzle structure described in this invention.

[0013] Beneficial effects: The key technology of the tightly coupled nozzle structure provided by this invention is the adjustment of the vertical distance between the air outlet of the spray disc and the outer wall of the guide tube. Experiments have shown that setting the vertical distance to 1-2 mm can greatly promote the interaction intensity between the atomizing gas and the molten metal flow, improve atomization efficiency, and increase the yield of fine powder. At the same time, the contraction angle of the contraction section of the guide tube is optimized, so that the airflow ejected from the air outlet of the spray disc and the molten metal flowing out of the guide tube maintain appropriate interaction, and the position of the atomization return zone is reasonably controlled, thereby improving the gas / liquid ratio. While obtaining a higher yield of fine powder, the probability of nozzle clogging is reduced, ensuring the continuity and stability of the atomization powder making process, thereby improving economic benefits. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of a tightly coupled nozzle structure according to the present invention.

[0015] Figure 2 The image shows a scanning electron microscope (SEM) image of the iron-based alloy powder in Example 1.

[0016] Figure 3 This is a scanning electron microscope image of the iron-based alloy powder from Example 2.

[0017] Figure 4 This is a scanning electron microscope image of the iron-based alloy powder in Example 3.

[0018] Figure 5 The image shows the burn-out of the spray disc during the gas atomization process in Comparative Example 1.

[0019] Figure 6 The image shows a scanning electron microscope (SEM) image of the iron-based alloy powder in Comparative Example 2. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0021] Please see Figure 1 , Figure 1 A schematic diagram of a tightly coupled nozzle structure provided by the present invention is shown in the figure. It includes an atomizing spray disc 10 and a guide pipe 20 tightly coupled to 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. After the spray disc upper cover 1 and the spray disc base 2 are sealed together, they form a gas resonance chamber 5 and a spray disc outlet 6. A central hole penetrating the thickness of the spray disc upper cover 1 is provided at the center of the spray disc upper cover 1. The guide pipe 20 is inserted into the central hole and flows through the gas... The atomizing spray disc 10 forms a tightly coupled assembly structure; the vertical distance between the air outlet 6 of the spray disc and the outer wall of the guide tube 20 is equal to the thickness of the bottom ring 8 of the spray disc cover 1, and the thickness of the bottom ring 8 of the spray disc cover is 1-2mm; the inner core 3 of the guide tube 20 is a cylindrical hole, 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°.

[0022] The key technology of the tightly coupled nozzle structure provided by this invention is the adjustment of the vertical distance between the air outlet 6 of the spray disc and the outer wall of the guide tube 20. Experiments have shown that setting the vertical distance to 1-2 mm can greatly promote the interaction intensity between the atomizing gas and the molten metal flow, improve atomization efficiency, and increase the yield of fine powder. At the same time, the contraction angle of the converging section 7 of the guide tube is optimized to 30-60°, so that the airflow ejected from the air outlet of the spray disc and the molten metal flowing out of the guide tube 20 maintain appropriate interaction. The position of the atomization backflow zone is reasonably controlled, which not only improves the gas / liquid ratio and obtains a higher yield of fine powder, but also avoids the upward backflow of the molten metal flow, thereby reducing the probability of nozzle blockage and spray disc burnout, ensuring the continuity and stability of the atomization powder production process, and thus improving economic benefits.

[0023] In some embodiments, the inner core diameter of the guide tube is 3-6 mm, the height of the cylindrical section of the guide tube is 8-15 mm, and the height of the constriction section is 2-6 mm. In this embodiment, the constriction section of the guide tube refers to the section where the end of the guide tube extends above the bottom ring of the spray disc cover. The constriction section is funnel-shaped, and the constriction angle of the constriction section refers to the angle between the line connecting the top edge of the constriction section to the end of the constriction section and the central axis of the inner core of the guide tube. In this embodiment, the parameter ranges of the inner core diameter, cylindrical section height, and constriction section height of the guide tube are all obtained through experimental design. Within this range, the flow rate of the molten metal is moderate and can maintain sufficient interaction with the airflow ejected from the air outlet of the spray disc, achieving a high fine powder yield while maintaining a high gas / liquid ratio.

[0024] In some embodiments, the flow channel of the gas resonant chamber is designed as a Laval structure or a tapered structure, but is not limited thereto.

[0025] In some embodiments, the guide tube is made of ZrO2 ceramic material or SiC ceramic material, but is not limited thereto.

[0026] In some embodiments, a gas atomizing device is also provided, which includes the tightly coupled nozzle structure described in this invention. When using a gas atomizing device with the tightly coupled nozzle structure of this invention to prepare fine metal powders, a high fine powder yield can be obtained while reducing the probability of nozzle clogging and spray disc burn-out, ensuring the continuity and stability of the atomization powder preparation process and improving economic efficiency.

[0027] The present invention will be further explained and illustrated below through specific embodiments:

[0028] Example 1

[0029] This embodiment optimizes the coupling distance between the air outlet of the spray disc and the guide tube, and improves the contraction angle at the end of the guide tube, thereby reducing the probability of spray disc burnout during the atomization process.

[0030] The atomizing device provided in this embodiment uses a slit-type nozzle, and the gas flow channel of the spray disc is designed with a Laval structure. The bottom ring thickness of the spray disc cover is 1.0 mm, the inner diameter of the guide tube is 4.5 mm, and the height of the cylindrical section of the guide tube is 6.0 mm. The height of the constricted section of the guide tube is 3.5 mm, and the constriction angle at the end of the guide tube is 35°. The upper end of the cylindrical section of the guide tube is tightly connected to the tundish, and the metal liquid outlet is located below the constricted section of the guide tube. Other structural components of the atomizing device in this embodiment are the same as those of existing atomizing devices.

[0031] An on-site industrial test was conducted, in which the iron-based alloy was heated and melted in a crucible in a melting chamber to obtain a molten alloy stream. The molten alloy stream was then introduced into an tundish and flowed out through a guide pipe, where it interacted with atomizing gas sprayed from an atomizing spray plate. This caused the molten alloy stream to break into small droplets, which, upon cooling, formed fine metal powder. The fine metal powder was collected using a powder collection tank. In this embodiment, the vacuum degree of the gas atomization equipment is ≤5×10⁻⁶. -3 Pa, the atomizing gas is argon or nitrogen, the atomization temperature of the steel casting is 1650℃, and the atomization pressure is 4.0MPa.

[0032] The results of Example 1 show that the gas atomization process is continuous, and no burn-off of the spray disc occurs. The prepared iron-based alloy powder is as follows: Figure 2 As shown, it has good sphericity and good fluidity.

[0033] Example 2

[0034] In this embodiment, by optimizing the coupling distance between the air outlet of the spray disc and the guide tube, and improving the contraction angle at the end of the guide tube, the probability of the spray disc burning during the atomization process is reduced.

[0035] The atomizing device provided in this embodiment adopts a slit-type nozzle, the gas flow channel of the spray disc is designed as a Laval structure, the bottom ring thickness of the spray disc cover is 1.5mm, the inner diameter of the guide tube is 3mm, the height of the cylindrical section of the guide tube is 7mm, the height of the constriction section of the guide tube is 2mm, the constriction angle at the end of the guide tube is 45°, the upper end of the cylindrical section of the guide tube is tightly connected to the tundish, and the metal liquid outlet is located below the constriction section of the guide tube.

[0036] An on-site industrial test was conducted, in which the iron-based alloy was heated and melted in a crucible in a melting chamber to obtain a molten alloy stream. The molten alloy stream was then introduced into an tundish and flowed out through a guide pipe, where it interacted with atomizing gas sprayed from an atomizing spray plate. This caused the molten alloy stream to break into small droplets, which, upon cooling, formed fine metal powder. The fine metal powder was collected using a powder collection tank. In this embodiment, the vacuum degree of the gas atomization equipment is ≤5×10⁻⁶. -3 Pa, the atomizing gas is argon or nitrogen, the atomization temperature of the steel casting is 1600℃, and the atomization pressure is 3.5MPa.

[0037] The results of Example 2 show that the gas atomization process is continuous, no spray disc burn-out occurs, and the prepared iron-based alloy powder is as follows: Figure 3 As shown, it has good sphericity and good fluidity.

[0038] Example 3

[0039] In this embodiment, by optimizing the coupling distance between the air outlet of the spray disc and the guide tube, and improving the contraction angle at the end of the guide tube, the probability of the spray disc burning during the atomization process is reduced.

[0040] The atomizing device provided in this embodiment adopts a slit-type nozzle, the gas flow channel of the spray disc is designed as a Laval structure, the bottom ring thickness of the spray disc cover is 2mm, the inner diameter of the guide tube is 5mm, the height of the cylindrical section of the guide tube is 6mm, the height of the constriction section of the guide tube is 3mm, the constriction angle at the end of the guide tube is 60°, the upper end of the cylindrical section of the guide tube is tightly connected to the tundish, and the metal liquid outlet is located below the constriction section of the guide tube.

[0041] An on-site industrial test was conducted, in which the iron-based alloy was heated and melted in a crucible in a melting chamber to obtain a molten alloy stream. The molten alloy stream was then introduced into an tundish and flowed out through a guide pipe, where it interacted with atomizing gas sprayed from an atomizing spray plate. This caused the molten alloy stream to break into small droplets, which, upon cooling, formed fine metal powder. The fine metal powder was collected using a powder collection tank. In this embodiment, the vacuum degree of the gas atomization equipment is ≤5×10⁻⁶. -3 Pa, the atomizing gas is argon or nitrogen, the atomization temperature of the steel casting is 1550℃, and the atomization pressure is 3.5MPa.

[0042] The results of Example 3 show that the gas atomization process is continuous, and no burn-off of the spray disc occurs. The prepared iron-based alloy powder is as follows: Figure 4 As shown, it has good sphericity and good fluidity.

[0043] Comparative Example 1

[0044] The atomizing device provided in Comparative Example 1 uses a slit-type nozzle, the gas flow channel of the spray disc is designed with a Laval structure, the bottom ring thickness of the spray disc cover is 0.5 mm, the inner diameter of the guide tube is 4.5 mm, the height of the cylindrical section of the guide tube is 6 mm, the height of the constriction section of the guide tube is 3 mm, the constriction angle at the end of the guide tube is 40°, the upper end of the cylindrical section of the guide tube is tightly connected to the tundish, and the metal liquid outlet is located below the constriction section of the guide tube.

[0045] An on-site industrial test was conducted, in which the iron-based alloy was heated and melted in a crucible in a melting chamber to obtain a molten alloy stream. The molten alloy stream was then introduced into an tundish and flowed out through a guide pipe, where it interacted with atomizing gas sprayed from an atomizing spray plate. This caused the molten alloy stream to break into small droplets, which, upon cooling, formed fine metal powder. The fine metal powder was collected using a powder collection tank. In this embodiment, the vacuum degree of the gas atomization equipment is ≤5×10⁻⁶. -3 Pa, the atomizing gas is argon or nitrogen, the atomization temperature of the steel casting is 1650℃, and the atomization pressure is 3.5MPa.

[0046] Comparative Example 1 shows that the spray disc burn-out phenomenon occurs during the atomization process, such as... Figure 5 As shown, when gas atomization terminates, the iron-based alloy melt solidifies and blocks at the end of the guide tube, and some of the iron-based alloy melt adheres to the surface of the spray disc, burning the spray disc.

[0047] Comparative Example 2

[0048] The atomizing device provided in Comparative Example 2 uses a slit-type nozzle, the gas flow channel of the spray disc is designed with a Laval structure, the bottom ring thickness of the spray disc cover is 2.5 mm, the inner diameter of the guide tube is 4.5 mm, the height of the cylindrical section of the guide tube is 6 mm, the height of the constriction section of the guide tube is 3 mm, the constriction angle at the end of the guide tube is 70°, the upper end of the cylindrical section of the guide tube is tightly connected to the tundish, and the metal liquid outlet is located below the constriction section of the guide tube.

[0049] An on-site industrial test was conducted, in which the iron-based alloy was heated and melted in a crucible in a melting chamber to obtain a molten alloy stream. The molten alloy stream was then introduced into an tundish and flowed out through a guide pipe, where it interacted with atomizing gas sprayed from an atomizing spray plate. This caused the molten alloy stream to break into small droplets, which, upon cooling, formed fine metal powder. The fine metal powder was collected using a powder collection tank. In this embodiment, the vacuum degree of the gas atomization equipment is ≤5×10⁻⁶. -3 Pa, the atomizing gas is argon or nitrogen, the atomization temperature of the steel casting is 1650℃, and the atomization pressure is 3.5MPa.

[0050] Comparative Example 2 shows that the gas atomization process was continuous and no spray disc burn-out occurred, but the prepared iron-based alloy powder... Figure 6 As shown, with increased satellite powder content, the sphericity is poor and the powder flowability is poor.

[0051] Comparative Example 2

[0052] The atomizing device provided in Comparative Example 3 uses a slit-type nozzle, the gas flow channel of the spray disc is designed with a Laval structure, the bottom ring thickness of the spray disc cover is 2mm, the inner diameter of the guide tube is 4.5mm, the height of the cylindrical section of the guide tube is 6mm, the height of the constriction section of the guide tube is 3mm, the constriction angle at the end of the guide tube is 10°, the upper end of the cylindrical section of the guide tube is tightly connected to the tundish, and the metal liquid outlet is located below the constriction section of the guide tube.

[0053] An on-site industrial test was conducted, in which the iron-based alloy was heated and melted in a crucible in a melting chamber to obtain a molten alloy stream. The molten alloy stream was then introduced into an tundish and flowed out through a guide pipe, where it interacted with atomizing gas sprayed from an atomizing spray plate. This caused the molten alloy stream to break into small droplets, which, upon cooling, formed fine metal powder. The fine metal powder was collected using a powder collection tank. In this embodiment, the vacuum degree of the gas atomization equipment is ≤5×10⁻⁶. -3 Pa, the atomizing gas is argon or nitrogen, the atomization temperature of the steel casting is 1650℃, and the atomization pressure is 3.5MPa.

[0054] Comparative Example 3 shows that during the gas atomization process, the spray disc burns out. Upon termination of gas atomization, the molten iron-based alloy solidifies and blocks at the end of the guide tube, with some of the molten iron-based alloy adhering to the surface of the spray disc, resulting in burn-out of the spray disc. This is because the contraction angle at the end of the guide tube decreases, causing the position of the atomization backflow zone to rise, thus leading to spray disc burn-out due to backflow of the molten iron-based alloy during gas atomization.

[0055] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A tightly coupled nozzle structure, characterized in that, The device includes an atomizing spray disc and a guide tube tightly coupled to the atomizing spray disc. The atomizing spray disc consists of a coaxial spray disc cover and a spray disc base. After the spray disc cover and the spray disc base are combined and sealed, they form a gas resonance chamber and a spray disc outlet. A central hole penetrating the thickness of the spray disc cover is provided at the center of the spray disc cover. The guide tube is inserted into the central hole and forms a tightly coupled assembly structure with the atomizing spray disc. The vertical distance between the spray disc outlet and the outer wall of the guide tube is equal to the bottom ring of the spray disc cover. The thickness of the bottom ring of the spray disc cover is 1-2 mm; the inner core of the guide tube is a cylindrical hole, and the outer part is an integrally formed cylindrical section and a contraction section. The upper end of the cylindrical section is the molten metal inlet, and the end of the contraction section is the molten metal outlet; the contraction angle of the contraction section of the guide tube is 30-60°; the inner core hole diameter of the guide tube is 3-6 mm; the height of the cylindrical section of the guide tube is 8-15 mm, and the height of the contraction section is 2-6 mm; the flow channel design of the gas resonance chamber is a Laval structure or a tapered structure.

2. The tightly coupled nozzle structure according to claim 1, characterized in that, The guide tube is made of ZrO2 ceramic material or SiC ceramic material.

3. A gas atomizing device, characterized in that, Includes the tightly coupled nozzle structure as described in any one of claims 1-2.

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