Airflow guide tube for gas atomization powder production

Abstract

The utility model relates to the technical field of gas atomization powder making, concretely relates to a gas atomization powder making flow guide pipe, which comprises: a liquid receiving part, a first flow channel is formed in the center of the liquid receiving part along the axial direction, and the first flow channel is a tapered structure that gradually narrows; a liquid guiding part, the liquid guiding part and the liquid receiving part are coaxially arranged as an integrated structure, a second flow channel that is in communication with the first flow channel is formed in the center of the liquid guiding part, the second flow channel is coaxially arranged with the first flow channel, a plurality of spiral grooves are formed around the side wall of the second flow channel, and the spiral grooves penetrate through both ends of the liquid guiding part. Through the above arrangement, the metal melt flow is ensured to be continuous and stable, and under the condition of the same atomization gas pressure, metal powder with finer granularity can be prepared, the preparation cost is reduced, the powder making quality is further improved, the residence time of the metal melt in the liquid guiding part is reduced, the probability of fouling and impurity deposition is effectively reduced, and the flow guide pipe is prevented from being blocked.

Description

Technical Field

[0001] This utility model relates to a guide tube for gas atomization powder making, belonging to the field of gas atomization powder making technology. Background Technology

[0002] Gas atomization powder production technology involves heating an alloy to a certain temperature in a crucible under vacuum or gas-protected heating conditions. A hydraulic or electric drive tilts the melting crucible, pouring the molten metal into a tundish crucible. The molten metal then enters the atomization zone through a guide pipe at the bottom of the insulated tundish crucible. Within the atomization zone, high-pressure gas (such as inert gas) forms a high-speed jet through atomizing nozzles, breaking up and atomizing the molten metal into fine droplets. These droplets travel within the atomization chamber below and rapidly cool and solidify, ultimately becoming micron-sized powder particles.

[0003] As a key tool for conveying molten metal to the atomization zone, the guide tube's material and structural design largely determine the stability of the atomization process and the quality and performance of the prepared metal powder. Traditional guide tubes have smooth inner holes. When guiding the flow of molten metal and interacting with the atomizing gas, the molten metal column formed by the smooth-hole structure requires significant atomizing gas energy to cause surface ripples and subsequent atomization and cooling into metal powder. Existing guide tube structures suffer from problems in practical applications, including insufficient molten metal kinetic energy, unstable molten metal flow, easy flow interruption, easy scaling and impurity deposition inside the guide tube, excessive atomizing gas consumption, and high powder preparation costs. Therefore, researching a novel guide tube for gas atomization powder production is of great practical significance. Summary of the Invention

[0004] This utility model addresses the shortcomings of existing technologies by providing a guide tube for gas atomization powder production.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: a guide tube for gas atomization powder making, comprising: a liquid receiving part, wherein a first flow channel is opened along the axial direction at the center of the part, and the first flow channel is a tapered structure that gradually narrows;

[0006] The liquid guiding part and the liquid receiving part are an integral structure coaxially arranged. A second flow channel communicating with the first flow channel is opened in the center of the liquid guiding part. The second flow channel is coaxially arranged with the first flow channel and a plurality of spiral grooves are opened around the side wall of the second flow channel. The spiral grooves penetrate through both ends of the liquid guiding part.

[0007] Furthermore, each of the spiral grooves has the same structure and the spacing between adjacent spiral grooves is equal, and the deflection angle of the spiral groove relative to the axis of the guide tube is 30-40 degrees.

[0008] Furthermore, the cross-sectional shape of the spiral groove is semi-circular, triangular, or rectangular.

[0009] Furthermore, the relationship between the axial height L1 of the guide tube body, the axial height L2 of the liquid receiving part, and the axial height L3 of the liquid guiding part satisfies: L1:L2:L3=1:(0.6-0.75):(0.25-0.4).

[0010] Furthermore, the second flow channel includes a tapered section that gradually tapers from top to bottom and a cylindrical section of equal diameter. The tapered section is located in the upper part of the second flow channel and communicates with the first flow channel, while the cylindrical section is located in the lower part of the second flow channel and communicates with the tapered section.

[0011] Furthermore, the axial height H1 of the conical section is 0.17-0.2 times the axial height L3 of the liquid guiding part.

[0012] Furthermore, the relationship between the inner diameter D of the cylindrical segment, the sidewall thickness K1 of the cylindrical segment, and the groove depth K2 of the spiral groove satisfies D:K1:K2=1:(0.4-0.6):(0.05-0.1).

[0013] Furthermore, the maximum width W of the spiral groove is 1.5-2.0 times the depth K2 of the spiral groove.

[0014] Furthermore, a support platform is integrally formed around the outer circumference of the liquid receiving portion, and a flange is integrally formed around the outer circumference of the liquid guiding portion, with the lower surface of the flange flush with the lower surface of the liquid guiding portion.

[0015] Furthermore, the guide tube is made of one or more composite materials selected from aluminum oxide, magnesium oxide, zirconium oxide, silicon carbide, and boron nitride.

[0016] The beneficial effects of this utility model are:

[0017] (1) By setting a gradually shrinking conical first flow channel, the velocity of the molten metal can be effectively increased when the molten metal flows through the first flow channel, thereby enhancing the kinetic energy of the molten metal and improving the energy exchange efficiency between the subsequent atomizing gas and the molten metal. It can also play a role in stabilizing the flow, ensuring the continuous and stable flow of the molten metal, providing a stable foundation for subsequent atomization, and avoiding the problem that the molten metal cannot fill the first flow channel when flowing, which would cause turbulence and generate bubbles that would affect the powder production quality.

[0018] (2) By setting several spiral grooves on the side wall of the second flow channel, when the molten metal flows through the second flow channel, the liquid flow is guided to generate circumferential rotation, which effectively enhances the surface fluctuation of the molten metal flow and increases the tangential velocity of the molten metal flow, so that the molten metal breaks at the outlet of the guide tube. Under the same atomizing gas pressure conditions, finer metal powder can be prepared, reducing the preparation cost and further improving the powder quality. In addition, the swirling effect of the spiral grooves can destroy the laminar boundary layer of the molten metal flow, reduce the residence time of the molten metal in the guide section, effectively reduce the probability of scaling and impurity deposition, and avoid blockage of the guide tube.

[0019] (3) The first and second flow channels work together. The molten metal flow accelerated by the first flow channel completes the conversion of kinetic energy to swirling kinetic energy in the second flow channel, forming a composite flow mode of "axial high speed + tangential rotation". Through the coordinated work of the first and second flow channels, compared with a single structure, under the same atomizing gas pressure conditions, the atomization efficiency is increased by 20%, the fine powder yield is increased by more than 10%, and the sphericity reaches more than 90%. Attached Figure Description

[0020] Figure 1 This is a front view of the guide tube provided in an embodiment of the present utility model;

[0021] Figure 2 for Figure 1 Sectional view along line AA;

[0022] Figure 3 This is a bottom view of the guide tube provided in an embodiment of the present utility model;

[0023] Figure 4 for Figure 3 Enlarged view of the structure at point C.

[0024] Reference numerals: 1. Liquid receiving part; 2. First flow channel; 3. Liquid guiding part; 4. Second flow channel; 5. Spiral groove; 6. Conical section; 7. Cylindrical section; 8. Support platform; 9. Flange. Detailed Implementation

[0025] The specific embodiments of this utility model are described in detail below. This utility model can be implemented in many ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used is for describing particular embodiments only and is not intended to limit the scope of this invention.

[0027] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0029] Example:

[0030] like Figure 1-3 As shown, this utility model provides a guide tube for gas atomization powder making, including: a liquid receiving part 1, with a first flow channel 2 opened axially at its center, the first flow channel 2 being a gradually narrowing conical structure, preferably, the taper of the first flow channel 2 being 4-5 degrees; a liquid guiding part 3, the liquid guiding part 3 and the liquid receiving part 1 being an integral structure coaxially arranged, with a second flow channel 4 opened at its center communicating with the first flow channel 2, the second flow channel 4 being coaxially arranged with the first flow channel 2 and having a plurality of spiral grooves 5 opened around the side wall of the second flow channel 4, the spiral grooves 5 penetrating both ends of the liquid guiding part 3, in this embodiment of the application, 6 spiral grooves 5 are opened on the side wall of the second flow channel 4, the number of spiral grooves 5 can be set according to actual performance requirements, and is not limited to the embodiment shown in the accompanying drawings of this application. It is understandable that the molten metal to be atomized, heated and melted in the crucible of the smelting furnace, is poured into the tundish and enters the atomization zone through the first flow channel 2 and the second flow channel 4 set in the guide pipe at the bottom of the tundish. "The spiral groove 5 penetrates both ends of the liquid guiding part 3" means that the plane at one end of the spiral groove 5 is the same plane as the plane at one end of the liquid guiding part 3, and the plane at the other end of the spiral groove 5 is also the same plane as the plane at the other end of the liquid guiding part 3. It should be noted that the dashed line X1 in the attached figure is the axis of the guide pipe described in this application, and the dashed line X2 is only used to distinguish the location of the liquid guiding part 3 and the liquid receiving part 1.

[0031] First, by setting a gradually narrowing conical first flow channel 2, the velocity of the molten metal is effectively increased as it flows through the first flow channel 2, enhancing its kinetic energy and improving the energy exchange efficiency between the subsequent atomizing gas and the molten metal. It also acts as a flow stabilizer, ensuring a continuous and stable flow of the molten metal, providing a stable foundation for subsequent atomization and preventing the molten metal from failing to fill the first flow channel 2, leading to turbulence and bubbles that affect powder production quality. Second, by setting several spiral grooves 5 on the sidewall of the second flow channel 4, the molten metal is guided to rotate circumferentially as it flows through the second flow channel 4, effectively enhancing the surface ripples of the molten metal flow and increasing its tangential velocity. This causes the molten metal to break up at the outlet of the guide pipe, under the same atomizing gas pressure. Under the given conditions, finer metal powder can be produced, reducing production costs and further improving powder quality. Furthermore, the swirling effect of the spiral groove 5 can disrupt the laminar boundary layer of the molten metal flow, reducing the residence time of the molten metal in the guide section 3, effectively reducing the probability of scaling and impurity deposition, and preventing blockage of the guide pipe. Finally, the first flow channel 2 and the second flow channel 4 work together, and the molten metal flow accelerated by the first flow channel 2 completes the conversion of kinetic energy to swirling kinetic energy in the second flow channel 4, forming a composite flow mode of "axial high speed + tangential rotation". Through the synergistic cooperation of the first flow channel 2 and the second flow channel 4, compared with a single structure, under the same atomizing gas pressure conditions, the atomization efficiency is increased by 20%, the fine powder yield is increased by more than 10%, and the sphericity reaches more than 90%.

[0032] Specifically, each of the spiral grooves 5 has the same structure and the spacing between adjacent spiral grooves 5 is equal. The deflection angle of each spiral groove 5 relative to the axis X1 of the guide tube is 30-40 degrees. It should be noted that the deflection angle refers to the angle formed by the projections of the two ends of the spiral groove 5 onto a plane perpendicular to the axis of the guide tube, relative to the axis of the guide tube. By setting the spiral grooves 5 to have the same structure and equal spacing, the stability of the liquid guiding part 3 can be ensured, avoiding local stress concentration that affects service life. Furthermore, the design of the deflection angle of the spiral groove 5 is crucial. If the deflection angle of the spiral groove 5 relative to the axis of the guide tube is less than 30 degrees, the tangential velocity of the molten metal flow will be insufficient, requiring an additional increase in the atomizing gas pressure to achieve the same fine powder yield, thus increasing production costs. If the deflection angle of the spiral groove 5 relative to the axis of the guide tube is greater than 40 degrees, the flow path of the molten metal in the spiral groove 5 will be too long. This can easily lead to localized flow dead zones in the spiral groove 5, causing high-melting-point oxides or refractory material residues in the molten metal to deposit within it. This results in molten metal residue and subsequent nodules within the groove. These nodules not only affect the flow of the molten metal, leading to insufficient tangential velocity and reduced atomization efficiency and powder quality, but also cause localized thermal stress concentration in the guide tube, increasing the likelihood of cracks or even breakage. Only when the deflection angle of the spiral groove 5 relative to the axis of the guide tube is 30-40 degrees can the atomization powder quality and efficiency be improved while ensuring the structural strength and service life of the guide tube.

[0033] Specifically, the cross-sectional shape of the spiral groove 5 is semi-circular, triangular or rectangular. In order to avoid stress concentration in the spiral groove 5 and reduce the deposition of debris in the spiral groove 5, the cross-sectional shape of the spiral groove 5 is preferably semi-circular in this embodiment.

[0034] Specifically, the relationship between the axial height L1 of the guide tube body, the axial height L2 of the liquid receiving part 1, and the axial height L3 of the liquid guiding part 3 satisfies: L1:L2:L3=1:(0.6-0.75):(0.25-0.4). This utility model, through the limitation of the above relationship, aims to further coordinate the balance between the atomized powder quality and the service life of the guide tube. If the axial height L2 of the liquid receiving part 1 is less than 0.6 times the axial height L1 of the guide tube body, the molten metal flows through for too short a time, failing to stabilize the flow and resulting in coarse-sized metal powder particles. If L2 is greater than 0.75 times L1, the liquid receiving part 1 holds too much molten metal, leading to thermal stress concentration at the liquid receiving part 1, increasing the probability of thermal shock during atomization and thus threatening the lifespan of the guide tube. Service life of the flow tube; Only when the relationship between the axial height L1 of the flow tube body, the axial height L2 of the liquid receiving part 1 and the axial height L3 of the liquid guiding part 3 satisfies the above formula can the relationship between the liquid guiding part 3 and the liquid receiving part 1 be balanced. At this time, the liquid receiving part 1 can accommodate an appropriate amount of molten metal, and the cooling of the flow tube can be delayed through the heat conduction of the tube wall, avoiding local overheating that leads to cracks in the flow tube or local overcooling that leads to cooling nodules in the liquid guiding part 3. At the same time, it can ensure that the tangential velocity of the molten metal flow can be effectively increased when it flows through the liquid guiding part 3, thereby ensuring the quality of atomization powder production.

[0035] Specifically, the second flow channel 4 includes a tapered section 6 that gradually tapers from top to bottom and a cylindrical section 7 of equal diameter. The tapered section 6 is located at the upper part of the second flow channel 4 and communicates with the first flow channel 2, while the cylindrical section 7 is located at the lower part of the second flow channel 4 and communicates with the tapered section 6. It should be noted that in the attached figure, the dashed line X3 is only used to distinguish the locations of the liquid guiding part 3 and the liquid receiving part 1. Through this arrangement, the tapered first flow channel 2 of the liquid receiving part 1 and the tapered section 6 form a continuous contraction, realizing a gradual increase in the flow velocity of the molten metal. This avoids abrupt changes in the flow channel cross-section that could obstruct the flow of the molten metal, thereby suppressing the generation of eddies and ensuring that the molten metal flow stably adheres to the wall of the second flow channel 4. This allows the molten metal to fully contact the spiral groove 5, and the cylindrical section 7 receives the kinetic energy output from the tapered section 6 to maintain a uniform flow velocity of the molten metal, further ensuring the quality of atomized powder production. To further address the issues of uneven flow velocity gradient and low energy utilization, preferably, the axial height H1 of the conical section 6 is 0.17-0.2 times the axial height L3 of the liquid guiding section 3. This setting allows the molten metal to flow stably through the second flow channel 4, ensuring sufficient contact between the spiral groove 5 and the molten metal, while further preventing excessive compression of the molten metal due to excessive contraction of the conical section 6, which could cause turbulence.

[0036] Specifically, the relationship between the inner diameter D of the cylindrical segment 7, the sidewall thickness K1 of the cylindrical segment 7, and the groove depth K2 of the spiral groove 5 satisfies D:K1:K2=1:(0.4-0.6):(0.05-0.1). The thickness of the sidewall of the cylindrical segment 7 needs to balance structural strength with reduced manufacturing costs. If the sidewall thickness K1 is less than 0.4 times the inner diameter D of the cylindrical segment 7, the sidewall is too thin, resulting in insufficient rigidity of the guide tube at the location of the cylindrical segment 7. Under the combined influence of the impact of atomizing gas and thermal stress, it is prone to deformation. Furthermore, the temperature drop at this location is too rapid due to the atomizing gas, which can easily lead to the solidification of molten metal and blockage of the guide tube. If the sidewall thickness K1 is greater than 0.6 times the inner diameter D of the cylindrical segment 7, although the structural strength of the guide tube is improved, the excessive thickness leads to a large amount of manufacturing materials, increasing manufacturing costs. In addition, the excessively thick sidewall increases the distance between the gas atomizing nozzle and the molten metal flowing out of the guide tube. Under the same gas atomizing pressure, this results in larger particle size of the atomized metal powder and poorer atomization quality. The depth of the spiral groove 5 directly affects the kinetic energy transfer efficiency of the atomizing gas. If the depth of the spiral groove 5 is too small, when the inner diameter of the cylindrical section 7 is D, the tangential velocity of the molten metal flow drawn by the spiral groove 5 is insufficient, and a stable spiral flow field cannot be formed. This results in incomplete droplet breakage during atomization, and under the same atomizing gas pressure, the atomized metal powder has a larger particle size and poorer atomization quality. If the depth of the spiral groove 5 is too large, it will increase the risk of residue deposition in the groove, and the stress concentration at the bottom of the groove will weaken the overall structural strength of the guide tube sidewall, making it prone to fatigue cracks or fractures. Only when the above relationships are met can this application ensure atomization quality while having sufficient resistance to deformation and reducing the use of manufacturing materials, so as to further balance the relationship between the structural strength of the guide tube, manufacturing cost, and atomization quality.

[0037] Specifically, the maximum width W of the spiral groove 5 is 1.5-2.0 times the depth K2 of the spiral groove 5. This setting ensures that the surface area to volume ratio of the spiral groove 5 is appropriate, thereby ensuring the flow stability of the molten metal. It can both prevent excessive impurities from accumulating in the groove and prevent the molten metal from breaking up into smaller droplets due to dispersion.

[0038] Specifically, a support platform 8 is integrally formed around the outer circumference of the liquid receiving part 1. The support platform 8 provides rigid support to strengthen the local structural strength of the guide tube, reduce the vibration amplitude during atomization, and further extend the service life of the guide tube. A flange 9 is integrally formed around the outer circumference of the liquid guiding part 3, and the lower surface of the flange 9 is flush with the lower surface of the liquid guiding part 3. This is because during atomization, the molten metal flow at the outlet of the guide tube easily forms a continuous liquid film due to surface tension, resulting in dispersion of the atomized gas shear force and insufficient fine powder yield. The design that the lower surface of the flange 9 is flush with the lower surface of the liquid guiding part 3 forces the liquid flow to spread through geometric constraints, reduces the liquid film thickness, significantly improves the crushing efficiency, and the flange 9 can also increase the wall thickness at the outlet of the guide tube to reduce the risk of molten metal solidification and blockage at the outlet.

[0039] The guide tube is made of one or more composite materials selected from aluminum oxide, magnesium oxide, zirconium oxide, silicon carbide, and boron nitride.

[0040] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] For those skilled in the art, various modifications and improvements can be made without departing from the concept of this utility model, and these modifications and improvements are all within the protection scope of this utility model. The protection scope of this utility model is defined by the appended claims.

Claims

1. A flow guide for use in the gas atomization of a powder, characterized in that include: The liquid receiving part has a first flow channel opened along the axial direction at its center, and the first flow channel is a tapered structure that gradually narrows. The liquid guiding part and the liquid receiving part are an integral structure coaxially arranged. A second flow channel communicating with the first flow channel is opened in the center of the liquid guiding part. The second flow channel is coaxially arranged with the first flow channel and a plurality of spiral grooves are opened around the side wall of the second flow channel. The spiral grooves penetrate through both ends of the liquid guiding part.

2. The flow guide tube for aerosolizing a powder according to claim 1, wherein Each of the spiral grooves has the same structure and the spacing between adjacent spiral grooves is equal. The deflection angle of the spiral groove relative to the axis of the guide tube is 30-40 degrees.

3. The gas atomizing atomizing tube according to claim 2, wherein The cross-sectional shape of the spiral groove is semi-circular, triangular, or rectangular.

4. The gas atomizing atomizer of claim 1, wherein The relationship between the axial height L1 of the guide tube body, the axial height L2 of the liquid receiving part, and the axial height L3 of the liquid guiding part satisfies: L1:L2:L3=1:(0.6-0.75):(0.25-0.4).

5. The gas atomizing atomizing tube according to claim 4, wherein The second flow channel includes a tapered section that gradually tapers from top to bottom and a cylindrical section of equal diameter. The tapered section is located in the upper part of the second flow channel and communicates with the first flow channel, while the cylindrical section is located in the lower part of the second flow channel and communicates with the tapered section.

6. The gas atomizing atomizing tube according to claim 5, wherein The axial height H1 of the conical section is 0.17-0.2 times the axial height L3 of the liquid guiding part.

7. A guide tube for gas atomization powder production according to claim 5, characterized in that, The relationship between the inner diameter D of the cylindrical segment, the sidewall thickness K1 of the cylindrical segment, and the groove depth K2 of the spiral groove satisfies D:K1:K2=1:(0.4-0.6):(0.05-0.1).

8. The gas atomizing atomizing tube according to claim 7, wherein The maximum width W of the spiral groove is 1.5-2.0 times the depth K2 of the spiral groove.

9. The gas atomizing atomizing tube according to claim 1, wherein A support platform is integrally formed around the outer circumference of the liquid receiving part, and a flange is integrally formed around the outer circumference of the liquid guiding part, with the lower surface of the flange flush with the lower surface of the liquid guiding part.

10. The gas atomizing atomizing tube according to claim 1, wherein The guide tube is made of one or more composite materials selected from aluminum oxide, magnesium oxide, zirconium oxide, silicon carbide, and boron nitride.

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