Flow guide device for atomization powder making

Abstract

The utility model relates to the technical field of gas atomization powder making, in particular to a flow guiding device for atomization powder making, which comprises a heating part, a flow guiding part and a flow guiding part, the heat insulation pipe is of a hollow structure with two open ends and a mounting channel inside, a first step protruding towards the axis direction is arranged at the bottom end of the heat insulation pipe, the bottom surface of the first step is a conical surface sunken towards the inside of the heat insulation pipe, and the top surface of the heat insulation pipe is connected with the bottom surface of the heating part; a melt runner is arranged in the liquid guide pipe, the liquid guide pipe sequentially penetrates through the heating part and the heat insulation pipe from top to bottom, the lower end of the liquid guide pipe extends out of the bottom face of the heat insulation pipe by a preset distance, a second step is arranged on the outer side face of the liquid guide pipe, and the second step is matched with the first step to fix the position of the liquid guide pipe. The system stability during atomization work is ensured, the phenomenon that the liquid guide pipe is blocked is avoided, and the atomization efficiency and the quality of finished metal powder are effectively improved.

Description

Technical Field

[0001] The utility model relates to a flow guiding device for atomization powder making, belonging to the technical field of gas atomization powder making. Background Art

[0002] With the rapid development of the metal 3D printing industry, spherical metal powder, as the key raw material for metal 3D printing, its preparation and production technology is the core of the entire 3D printing industrial chain. At present, the vacuum melting inert gas atomization method is the main preparation method for preparing spherical powders of various alloys such as iron-based, nickel-based, copper-based, aluminum-based, and cobalt-based. Its basic principle is to melt the metal solid raw materials in a crucible by means of electromagnetic induction melting, make the liquid metal melt flow out through a flow guiding tube, and then be broken and atomized by the action of gas, and finally cooled and solidified to obtain spherical metal powder. The utility model patent with the publication number of CN201300208Y discloses a liquid guiding tube for high melting point alloy atomization. However, the technical solution disclosed in this patent still has problems such as poor stability during atomization work, low atomization efficiency, and poor quality of the finished metal powder, which need to be solved urgently. Content of the Utility Model

[0003] Aiming at the deficiencies of the existing technology, the utility model provides a flow guiding device for atomization powder making.

[0004] The technical solution for the utility model to solve the above technical problems is as follows: A flow guiding device for atomization powder making, comprising: a heating part, the heating part is a hollow structure with openings at both ends and an installation channel inside; a heat insulation tube, the heat insulation tube is a hollow structure with openings at both ends and an installation channel inside, and a first step protruding towards the axial center is provided at the bottom end thereof, and the bottom surface of the first step is set as a conical surface recessed towards the inside of the heat insulation tube, and the top surface of the heat insulation tube is connected to the bottom surface of the heating part; a liquid guiding tube, a melt flow channel is arranged inside the liquid guiding tube, the liquid guiding tube sequentially passes through the heating part and the heat insulation tube from top to bottom, and its lower end extends a predetermined distance out of the bottom surface of the heat insulation tube, and a second step is arranged on the outer side surface of the liquid guiding tube, and the second step cooperates with the first step to fix the position of the liquid guiding tube.

[0005] Further, a first conical surface is arranged on the lower end of the liquid guiding tube from inside to outside, the bottom end of the first conical surface is connected to the bottom end of a second conical surface arranged from outside to inside, and an included angle α is formed between the first conical surface and the second conical surface.

[0006] Further, the range of the included angle α is 55 - 125 degrees.

[0007] Further, the recessed conical surface arranged on the bottom surface of the first step and the plane where the connection point between the first step and the side wall of the heat insulation tube is located have an included angle β, and the range of the included angle β is 10 - 20 degrees.

[0008] Further, the bottommost end of the liquid guide tube is in the same plane as the bottommost end of the first step.

[0009] Further, there is a gap between the liquid guide tube and the heat insulation tube, and the range of the gap is 2 - 4 mm.

[0010] Further, the upper end of the liquid guide tube is a cylinder that fits the inner surface of the heating part, and its side wall is obliquely cut with a conical surface.

[0011] Further, the vertical height H1 between the topmost end and the bottommost end of the liquid guide tube is 9 - 13 times the inner diameter D1 of the liquid guide tube.

[0012] Further, the upper melt flow channel of the liquid guide tube is inverted conical.

[0013] Further, the heating part is made of graphite or graphite clay, the heat insulation tube is made of high-purity alumina or zirconia, and the liquid guide tube is made of alumina, zirconia, silicon carbide or boron nitride.

[0014] The beneficial effects of the present utility model are as follows:

[0015] (1) Through the cooperation of the first step and the second step between the liquid guide tube and the heat insulation tube, it not only avoids the twisting of the liquid guide tube under the action of the lateral force of the high-speed cold air flow during atomization powder making, ensures the system stability during atomization work, but also plays a sealing role, avoiding the rapid reduction of the metal melt temperature due to the cold air flow entering the gap between the liquid guide tube and the heat insulation tube, and preventing the phenomenon of affecting the quality of the finished metal powder and even causing blockage of the liquid guide tube.

[0016] (2) By providing a conical surface recessed towards the inside of the heat insulation tube on the bottom surface of the first step, the high-speed cold air flow will not directly impact the liquid guide tube, which can better maintain the temperature of the metal melt, avoid the occurrence of blockage of the liquid guide tube nozzle, and due to the protection of the heat insulation tube, the probability of breakage or damage of the liquid guide tube will also be significantly reduced. Secondly, because the recessed conical surface does not directly contact the high-speed cold air flow, it can better maintain the superheat degree of the metal melt blown onto the conical surface by the air flow field, enabling the accumulation of metal droplets to form a metal liquid film again, effectively improving the atomization efficiency and the quality of the finished metal powder, and the conical surface is also beneficial to the flow of the metal liquid film, which can further improve the atomization efficiency. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of an embodiment of the present utility model;

[0018] Figure 2 is a sectional view of an embodiment of the present utility model;

[0019] Figure 3 is a schematic structural diagram of the liquid guide tube provided by an embodiment of the present utility model;

[0020] Figure 4 Cross-sectional view of the liquid guide tube provided by the embodiment of the present utility model;

[0021] Figure 5 Enlarged view of part A of the cross-sectional view of the liquid guide tube provided by the embodiment of the present utility model;

[0022] Figure 6 Cross-sectional view of the heat insulation tube provided by the embodiment of the present utility model;

[0023] Figure 7 Enlarged view of part B of the cross-sectional view of the heat insulation tube provided by the embodiment of the present utility model.

[0024] Reference numerals: 1, heating part; 2, heat insulation tube; 21, first step; 3, liquid guide tube; 31, second step; 32, first conical surface; 33, second conical surface. Detailed implementation manners

[0025] The following makes a detailed description of the specific implementation manners of the present utility model. The present utility model can be implemented in many other ways different from those described herein. Those skilled in the art can make similar improvements without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs. The terms used are only for describing the specific implementation manners and do not limit the present utility model.

[0027] Such as Figure 1 And 2As shown in the figure, the present utility model provides a diversion device for atomization powder making, including a heating part 1. The heating part 1 is a hollow structure with openings at both ends and an installation channel inside. Its outer shape is a cylinder. The heating part 1 is used to generate heat to maintain the superheat of the molten metal, avoiding the risk of solidification and nozzle blockage caused by heat dissipation during the flow of the molten metal. Preferably, a end plate is integrally formed at the bottom end of the heating part 1. The end plate and the heating part 1 are coaxially provided with through holes. The inner diameter of the heating part 1 is larger than the inner diameter of the end plate, that is to say, the contact area between the heating part 1 and the heat insulation plate becomes larger, which is beneficial to improving the installation stability and better conducting the heat generated by the heating part 1 to the heat insulation tube 2 to further maintain the superheat of the molten metal; a heat insulation tube 2. The heat insulation tube 2 is a hollow structure with openings at both ends and an installation channel inside. A step protruding radially away from the axis is provided at the upper end of the heat insulation tube 2. The heating part 1 is placed above the heat insulation tube 2 and the bottom surface of the end plate is connected to the top surface of the heat insulation tube 2. It should be noted that in the embodiment of the present utility model, the lower end is the end close to the atomization chamber, and the upper end is the end close to the crucible. Preferably, the heat insulation tube 2 and the heating part 1 can be connected by abutting or by an adhesive, and a nano-thermal conductive material, such as graphite emulsion, etc., can be coated on the joint surface, which is beneficial to the better heat conduction of the heating part 1. A first step 21 protruding radially towards the axis is provided at the bottom end of the heat insulation tube 2. The bottom surface of the first step 21 is set as a conical surface recessed towards the inside of the heat insulation tube 2; a liquid guide tube 3. A through molten metal flow channel is provided inside the liquid guide tube 3. Its upper end is connected to the crucible. The liquid guide tube 3 sequentially passes through the heating part 1 and the heat insulation tube 2 from top to bottom, and its lower end extends a predetermined distance out of the bottom surface of the heat insulation tube 2. A second step 31 is provided on the outer side surface of the liquid guide tube 3. The cross section of the second step 31 is triangular. The second step 31 abuts against the first step 21 to fix the position of the liquid guide tube 3. When the liquid guide tube 3 is installed in place, the top surface of the first step 21 and the bottom surface of the second step 31 are in surface contact, and the side wall of the first step 21 and the side wall of the liquid guide tube 3 are in surface contact.

[0028] The liquid guiding tube 3 and the heat insulation tube 2 are fixed in position by the cooperation of the first step 21 and the second step 31. First, the position of the liquid guiding tube 3 is fixed to prevent the liquid guiding tube 3 from twisting under the action of the lateral force of the high-speed cold air flow during atomization powder making, ensuring the system stability during atomization work. Second, it also plays a sealing role to prevent the cold air flow from entering the gap between the liquid guiding tube 3 and the heat insulation tube 2, resulting in a rapid decrease in the temperature of the molten metal, avoiding affecting the quality of the finished metal powder and even causing the phenomenon of blockage of the liquid guiding tube 3. By providing a conical surface recessed towards the inside of the heat insulation tube 2 on the bottom surface of the first step 21, the part of the liquid guiding tube 3 extending out of the bottom surface of the heat insulation tube 2 is protected by the heat insulation tube 2. First, the high-speed cold air flow does not directly impact the liquid guiding tube 3, which can better maintain the temperature of the molten metal and avoid the occurrence of nozzle blockage of the liquid guiding tube 3. Second, due to the protection of the heat insulation tube 2, the probability of breakage or damage of the liquid guiding tube 3 is also greatly reduced. Finally, by setting it as a recessed conical surface, during the process that the molten metal flows out of the liquid guiding tube 3 to form a liquid film and then is impacted and crushed into liquid droplets by the high-speed cold air flow, because the recessed conical surface does not directly contact the high-speed cold air flow, the superheat degree of the molten metal blown onto the conical surface by the gas flow field can be better maintained, enabling the accumulation of metal liquid droplets to form a metal liquid film again, effectively improving the atomization efficiency and the quality of the finished metal powder. Moreover, the conical surface is also beneficial to the flow of the metal liquid film, which can further improve the atomization efficiency.

[0029] Specifically, a first conical surface 32 is arranged from the inside to the outside on the part of the lower end of the liquid guiding tube 3 extending out of the bottom surface of the heat insulation tube 2. The bottom end of the first conical surface 32 is connected to the bottom end of a second conical surface 33 arranged from the outside to the inside. An included angle α is formed between the first conical surface 32 and the second conical surface 33. When the liquid film forms to the connection part of the first conical surface 32 and the second conical surface 33, it can cooperate with the gas shear force to timely shear and break the metal liquid film into strips. Through the above settings, the shearing of the metal liquid film is strengthened, which can prevent the liquid film formed during the film formation process of the molten metal from being too thick, and further improve the atomization efficiency and the quality of the finished metal powder. Preferably, the range of the included angle α is 55 - 125 degrees. If the included angle α is less than 55 degrees, the first conical surface 32 is too long and not gentle enough. When the molten metal flows through, it is easy not to go through the film formation process or only part of the molten metal goes through the film formation process, resulting in a coarse particle size and poor sphericity of the finally produced finished metal powder. If the included angle α is greater than 125 degrees, although the first conical surface 32 is gentle enough to be beneficial to the formation of the liquid film at this time, its length is too short, and the formed liquid film does not have enough extension, easily leading to too thick a liquid film thickness, which will ultimately also affect the quality of the finished metal powder.

[0030] Specifically, the concave conical surface provided on the bottom surface of the first step 21 and the plane where the connection point between the first step 21 and the side wall of the heat insulation pipe 2 is located form an included angle β, and the range of the included angle β is 10 - 20 degrees. The setting within this range is very crucial. When the included angle β is less than 10 degrees, the protected range of the liquid guide pipe 3 by the heat insulation pipe 2 becomes smaller. Even if the extended length of the liquid guide pipe 3 remains unchanged, its end will still be directly impacted by the high-speed cold air flow at this time, resulting in the metal melt being easily cooled and solidified, causing phenomena such as nozzle blockage, stagnant flow, and even backspray of the liquid guide pipe 3. When the included angle β is greater than 20 degrees, although the liquid guide pipe 3 will be better protected by the heat insulation pipe 2 at the same extended length, that is, the distance between the plane where the bottom end of the liquid guide pipe 3 is located and the plane where the bottom end of the first step 21 is located becomes larger at this time, but the gas shear force of the high-speed air flow on the metal melt decreases, affecting the quality of the finished metal powder. Moreover, the distance from the metal melt to the converging focus of the high-speed cold air flow becomes larger. During the free fall process, more droplet surfaces solidify and cannot be secondarily broken and atomized by the high-speed cold air flow, resulting in a decrease in the fine powder rate of the finished metal powder, further affecting the quality of the finished metal powder. Only when the included angle β is within the range of 10 - 20 degrees can both ensure the quality of the finished metal powder and enable the liquid guide pipe 3 to be fully protected by the heat insulation pipe 2. Preferably, the bottom end of the liquid guide pipe 3 and the bottom end of the first step 21 are on the same plane. By setting them on the same plane, the quality of the finished metal powder can be further improved on the premise that the liquid guide pipe 3 is protected accordingly.

[0031] Specifically, there is a gap between the outer side wall of the liquid guide pipe 3 and the inner side wall of the heat insulation pipe 2, and the range of the gap is 2 - 4 mm. When the gap is less than 2 mm, there is not enough heat preservation space, and the superheat degree of the metal melt flowing through the liquid guide pipe 3 decreases rapidly, resulting in a decrease in the sphericity rate and fine powder rate of the finished metal powder, further affecting the quality of the finished metal powder. When the gap is greater than 4 mm, on the premise of maintaining the wall thickness of the heat insulation pipe 2, it will cause the radial dimension of the heat insulation pipe 2 to become larger. Because the heat insulation pipe 2 needs to be placed in the central hole between the atomizing air flow nozzles during use, the distance between the nozzles facing each other in the circumferential direction becomes larger accordingly, resulting in the downward shift of the converging focus of the high-pressure cold air flow, leading to a decrease in the fine powder rate of the finished metal powder and affecting the quality of the finished metal powder.

[0032] Specifically, the upper end of the liquid guide pipe 3 is a cylinder with an outer diameter larger than that of the lower end, and the outer surface of its upper end cylinder is matched with the inner surface of the heating part, which can be a clearance fit or an abutment. A conical surface slanting from the outside to the inside is cut on one side of the cylinder close to the atomizing chamber. By setting the slanted conical surface, it is convenient to position the heating part 1 and the liquid guide pipe 3 during installation.

[0033] Specifically, the vertical height H1 between the topmost and bottommost ends of the liquid guiding tube 3 is 9 - 13 times the inner diameter D1 of the liquid guiding tube 3. If the height-to-diameter ratio is greater than 13 times, the liquid guiding tube 3 is too slender, and when the molten metal flows in the relatively thin liquid guiding tube 3, it is very easy to solidify and cause blockage of the liquid guiding tube 3. If the height-to-diameter ratio is less than 9 times, the flow rate of the molten metal per unit time in the liquid guiding tube 3 increases, but the excessive flow rate of the molten metal will lead to uneven atomization powder making and a decrease in the fine powder rate of the finished metal powder.

[0034] Specifically, the upper flow path of the liquid guiding tube 3 close to the crucible is in an inverted conical shape. By setting it in an inverted conical shape, the flow rate of the molten metal can be increased, and the atomization efficiency can be further improved; the heating part 1 is made of graphite, or can also be made of materials such as graphite clay, the heat insulation tube 2 is made of high-purity alumina, or can also be made of materials such as zirconia, and the liquid guiding tube 3 is made of alumina, or can also be made of materials such as boron nitride, zirconia, and silicon carbide.

[0035] Table 1 is a comparison table of the mass and parameters of various sizes in the embodiments and comparative examples of the present invention;

[0036]

[0037]

[0038] Table 1

[0039] From the evaluation results of Example 1, Example 2, and Example 3, it can be seen that when the included angle α ranges from 55° to 125°, the included angle β ranges from 10° to 20°, the gap between the liquid guiding tube 3 and the heat insulation tube 2 ranges from 2 - 4 mm, and the vertical height H1 between the topmost and bottommost ends of the liquid guiding tube 3 is 9 - 13 times the inner diameter D1 of the liquid guiding tube 3, the fine powder rate, spherical rate, and particle size all perform excellently, and the finished metal powder has better quality. When the size parameters of Comparative Example 1 and Comparative Example 2 are used, the fine powder rate, spherical rate, and particle size of the finished metal powder are low, seriously affecting the quality control of the finished metal powder.

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

[0041] For those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. The protection scope of the present invention is subject to the appended claims.

Claims

1. A flow guiding device for atomization powder making, characterized in that, Comprising: A heating part, which is a hollow structure with openings at both ends and an installation channel inside; A heat insulation pipe, which is a hollow structure with openings at both ends and an installation channel inside. A first step protruding towards the axial direction is provided at the bottom end thereof, and the bottom surface of the first step is set as a conical surface recessed towards the inside of the heat insulation pipe. The top surface of the heat insulation pipe is connected to the bottom surface of the heating part; A liquid guide pipe, with a melt flow channel arranged inside. The liquid guide pipe sequentially passes through the heating part and the heat insulation pipe from top to bottom, and its lower end extends a predetermined distance out of the bottom surface of the heat insulation pipe. A second step is provided on the outer side surface of the liquid guide pipe, and the second step cooperates with the first step to fix the position of the liquid guide pipe.

2. The flow guiding device for atomization powder making according to claim 1, wherein, A first conical surface is arranged on the lower end of the liquid guide pipe from inside to outside, and the bottom end of the first conical surface is connected to the bottom end of a second conical surface arranged from outside to inside. An included angle α is formed between the first conical surface and the second conical surface.

3. The diversion device for atomization powder making according to claim 2, characterized in that The range of the included angle α is 55 - 125 degrees.

4. The flow guiding device for atomization powder making according to claim 1, characterized in that, The recessed conical surface provided on the bottom surface of the first step and the plane where the connection point between the first step and the side wall of the heat insulation pipe is located have an included angle β, and the range of the included angle β is 10 - 20 degrees.

5. A flow guiding device for atomization powder making according to claim 4, characterized in that, The lowermost end of the liquid guide pipe and the lowermost end of the first step are on the same plane.

6. The diversion device for atomization powder making according to claim 1, wherein There is a gap between the liquid guide pipe and the heat insulation pipe, and the range of the gap is 2 - 4 mm.

7. A flow guiding device for atomization powder making according to claim 1, characterized in that, The upper end of the liquid guide pipe is a cylinder that fits with the inner surface of the heating part, and its side wall is obliquely cut with a conical surface.

8. The diversion device for atomization powder making according to claim 1, characterized in that, The vertical height H1 between the uppermost end and the lowermost end of the liquid guide pipe is 9 - 13 times the inner diameter D1 of the liquid guide pipe.

9. The diversion device for atomization powder making according to claim 7, characterized in that, The melt flow channel in the upper part of the liquid guide pipe is an inverted cone.

10. The flow guiding device for atomization powder making according to claim 1, characterized in that The heating part is made of graphite or graphite clay, the heat insulation pipe is made of high-purity alumina or zirconia, and the liquid guide pipe is made of alumina, zirconia, silicon carbide or boron nitride.

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