KR20230116124A - Apparatus for Manufacturing Metal Powder Using Fluid Spray - Google Patents

Abstract

The present invention utilizes the accompanying air flow generated in the vicinity of the fluid jet when the fluid is jetted at high speed to primarily pulverize the metal molten metal stem and continuously refine it again by the fluid jet, thereby improving the efficiency of fluid spray powdering and the sphericity of the powder. It relates to a fluid spraying metal powder manufacturing apparatus capable of improving
An apparatus for producing a fluid spray metal powder according to the present invention includes an alloy melting unit for storing molten metal and having an orifice for discharging the molten metal at a lower portion thereof; The molten metal freely falls inside in the form of a molten metal stream through an orifice, and a plurality of gas circulation passages are installed on the bottom surface so that atmospheric gas circulates from the bottom of the inner circumference to the bottom of the center. a gas circulation chamber forming unit having; a first fluid ejection nozzle located at the center of the inner lower end of the gas circulation chamber forming part and generating fine metal droplets by spraying a high-velocity first fluid jet to the molten metal that freely falls through the center; and located at the lower end of the gas circulation chamber forming part, filled with the atmosphere gas, supplying the atmosphere gas to the gas circulation chamber through the gas circulation passage, and dispersing metal droplets generated by crushing the sprayed fluid and the molten metal stem. It is characterized in that it comprises a spraying chamber forming part having a spraying chamber for cooling and storing the metal powder therein.

Description

Fluid spraying metal powder manufacturing apparatus {Apparatus for Manufacturing Metal Powder Using Fluid Spray}

The present invention relates to an apparatus for manufacturing fluid-jet metal powder, and more particularly, to use an entrainment flow generated in the vicinity of a fluid jet when a fluid is jetted at a high speed to primarily pulverize a molten metal stem and continuously It relates to a fluid spray metal powder manufacturing apparatus capable of improving the fluid spray powderization efficiency and the sphericity of the powder by re-miniaturization by a fluid jet.

Recently, with the development of the metal 3D printing parts industry, which manufactures parts with complex shapes required for aviation, power generation, mold, automobile parts, and industrial machinery by 3D printing, the ferrous and non-ferrous powders used as raw materials Usage is soaring.

Metal 3D printing processes that are currently commercially available are divided into two types: laser-based processes and sintering-based processes. Currently, laser-based 3D printing technology precedes commercialization, but due to high manufacturing process costs, sinter-based 3D printing technology with low manufacturing cost is expected to become the mainstream for mass production commercialization in the future.

First, the metal laser-based 3D printing process uses the PBF (Powder Bed Fusion) method and the DED (Direct Energy Deposition) method. The metal PBF method requires a powder size of 45 μm or less, and the metal DED method requires a powder size of 60 μm to 150 μm. Among them, the PBF method accounts for more than 90% of the demand for metal powder, and the recovery rate is very low at 20% level to manufacture metal powder of 45 μm or less required for the PBF method by the existing gas injection manufacturing process, which is a problem. Due to such a low production yield, metal powders of 45μm or less for PBF 3D printing are expensive at least 150,000 won/kg, which is an obstacle to the widespread commercialization of the metal 3D printing process.

Second, the metal sintering-based 3D printing process uses a metal BJ (Binder Jetting) method and a metal FDM (Fused Deposition Modeling) method. Metal sintering-based 3D printing technology is a very inexpensive and high-productivity process technology that can complete parts directly by sintering complex shapes molded and joined with a binder. The metal BJ method requires a powder size of 45 μm or less, and the metal FDM method requires a powder size of 10 μm or less.

As such, metal powders of 45 μm or less have too low production yield by the gas spray process, and are poor in economic feasibility. There is a problem that has an irregular shape rather than a spherical shape. In order to secure the physical properties of 3D printed parts, the oxygen concentration contained in the metal powder must be low, and the shape of the metal powder must be close to a sphere to obtain the highest density of 3D printed parts.

Conventionally, ferrous and non-ferrous powders for 3D printing of parts having complex shapes are manufactured through a fluid spray metal powder manufacturing apparatus using a conical fluid jet. The molten metal of the crucible falls freely through the lower orifice, and a fluid spray nozzle that sprays a conical fluid jet is installed at the bottom, and a molten metal stream passes through the center. At this time, a circular slit or a plurality of fine jet holes are processed along the circular slit at the lower end of the fluid ejection nozzle to jet a conical high-speed fluid jet. These high-speed fluid jets are concentrated at one point at the apex of the lower cone, where they collide with the molten metal stream and pulverize the metal molten metal stream into fine droplets. Thereafter, the pulverized liquid droplets are solidified and cooled by the fluid injected inside the injection chamber, changed to solid metal powder, and finally accumulated in the powder collecting unit.

Liquid or gas may be used as the injection fluid. As the injection gas, an inert gas such as nitrogen (N ₂ ), argon (Ar) or helium (He) is mainly used, and sometimes air is also used. As the injection liquid, industrial water or oil is used. The injection gas pressure used in the gas injection nozzle is generally 5 Bar to 25 Bar, whereas the water pressure used in the water injection nozzle is generally 150 Bar to 1000 Bar, which is very high.

Fluid injection nozzle methods using these conventional conical fluid jets are largely classified into a Close-Coupled Type and a Free-Fall Type.

In the close-coupled fluid spray nozzle, the powdering efficiency is relatively excellent because the spray fluid and the molten metal stream are very close together. On the other hand, when liquid is applied as the spraying fluid, since the molten metal in the orifice is solidified and an operation accident occurs, only gas can be applied as the spraying fluid.

Since the injection gas is directly injected into the orifice, the orifice made of ceramic material is in an environment where it receives a large thermal shock. In other words, since molten metal of around 1600°C leaks out of the inner diameter of the orifice and cold injection gas at high speed passes through the outer periphery, it is difficult to endure for a long time, resulting in frequent operation accidents in which the orifice ruptures and becomes clogged. In addition, when the metal powder is manufactured by applying such a close-coupled gas injection nozzle, there is a problem in that the fluidity of the powder deteriorates because the ultrafine liquid droplets are welded to the surface of the powder as satellite powder and the surface of the powder becomes finely uneven. . Currently, the close-coupled gas injection metal powder manufacturing process is difficult to apply to mass commercial production, and is mainly applied to small-scale production or research and development.

On the other hand, the conventional free-falling fluid injection nozzle method can apply both gas or liquid as the injection fluid, and has the best operational stability, so it is currently mainly used for mass production of metal powder. However, since the ejected fluid jets collide with each other at one point of the free-falling molten metal stem, the colliding forces cancel each other out and the powdering efficiency decreases. The impact force of the fluid jets must be fully transferred to the molten metal stream, but most of the energy is consumed by the collision between the fluid jets, so a larger amount of fluid and a higher fluid pressure are required for powderization.

Moreover, since the ejected fluid jets gather at the narrow vertex of the cone shape, there is very little free space to contain the ejected fluid jets, resulting in severe upward vortexes in the area where they collide with each other. There is a high possibility that the falling molten metal stems are shaken and ruptured by these vortexes, resulting in non-uniform powder particle size and deterioration in the sphericity of the powder. In particular, these vortices do not escape downward and rise upward. When this backflow phenomenon reaches the orifice area, the molten metal near the orifice ruptures, solidifies, adheres to, and grows in the orifice. Eventually, the central penetrating part of the fluid injection nozzle is blocked by solidification of the molten metal, making it impossible to manufacture powder.

Free-fall fluid jet nozzles are advantageous for powder refinement because they can transmit a large impact force of the fluid jet if the collision angle between the molten metal stem and the fluid jet is increased. It is common to limit the collision angle between the fluid jet and the fluid jet to within 20°. Therefore, in order to manufacture fine metal powder, an excessive amount of fluid must be injected, and since the injected fluid is discarded for one-time use, the cost required for manufacturing the powder increases.

In addition, since the fluid jets are crushed into metal droplets at a certain part where they collide, and coalescence also occurs at the same time, the shape of the metal powder tends to become irregular. That is, the conventional free-fall type fluid spray nozzle has a problem in that the powder micronization efficiency is poor, which is unfavorable for manufacturing fine metal powder, and the sphericity of the manufactured metal powder is also poor.

In order to overcome the miniaturization efficiency limit of the powder manufacturing process using such a fluid injection nozzle, a technique of applying a dual fluid injection nozzle has been proposed. In an effort to increase the miniaturization efficiency by doubly overlapping fluid injection nozzles, a new function was attempted by combining a liquid jet and a gas jet in two methods, a close-coupled double injection nozzle and a free-falling double injection nozzle.

There was a prior art (Patent Document 0001-0004) for improving the existing gas injection and water injection powder manufacturing process by combining the same type of gas jet-gas jet or combining sujet-sujet, but was satisfied with powder refinement and spheroidization I didn't like it.

In addition, there was a prior art (Patent Documents 0005-0006) to overcome the disadvantages of the water injection and gas injection powder manufacturing process by combining heterogeneous liquid jet-gas jet, but this also accomplished the technology of preventing oxidation of metal powder and spheroidization was insufficient to do.

In fact, in the close-coupled dual-nozzle method, mass production of powder is practically impossible because fluid jets overlap in a very narrow area. In addition, the free-falling double-nozzle method has a problem in that the amount of fluid used is almost doubled, but the micronization is not remarkable, so the powder micronization efficiency is not good.

As described above, according to the prior art, the fluid injection powder refinement efficiency is reduced due to the excessive amount of fluid used for micronization, there is a problem with the sphericity of the metal powder, and unstable phenomena such as clogging of the orifice occur during the manufacturing process, resulting in poor operation reliability. There was a problem with being poor.

Korean Patent Publication No. 10-1995-0000268 Korean Registered Patent Publication No. 10-1426008 Korean Patent Publication No. 10-2018-0104910 Korean Patent Publication No. 10-2020-0070712 Korean Patent Publication No. 10-2016-0124068 Korean Patent Publication No. 10-2016-0024401

Therefore, the present invention has been proposed to solve the above problems of the prior art, and its purpose is to maximize the high-speed accompanying air flow generated adjacent to the fluid jet by opening the inner space surrounded by the jet of the jetted molten metal. It is an object of the present invention to provide an apparatus for manufacturing fluid spray metal powder capable of maximally improving the efficiency of powder refinement by performing primary pulverization and then continuously secondary pulverization with a high-speed fluid jet.

Another object of the present invention is to reduce fluid consumption for producing powder with the same particle size because the primary grinding occurs by the high-speed accompanying air flow generated adjacent to the fluid jet, and then the grinding is sequentially performed by the fluid jet, and the accompanying air flow is circulated. It is an object of the present invention to provide an economically advantageous fluid injection metal powder manufacturing apparatus by using the same.

Another object of the present invention is to prevent reverse flow and orifice clogging caused by collision back pressure because the internal space surrounded by the fluid jets is open and the high-speed accompanying air current generated adjacent to the fluid jets can flow through the center of the fluid jets at high speed. It is an object of the present invention to provide a fluid injection metal powder manufacturing apparatus capable of increasing operational reliability.

Another object of the present invention is to prevent the coalescence of the liquid droplets by causing secondary crushing by the fluid jet after the high-speed accompanying air flow generated adjacent to the fluid jet crushes the molten metal stream into droplets and sends them into the fluid jet, preventing the droplets from coalescing. It is an object of the present invention to provide a fluid injection metal powder manufacturing apparatus having excellent sphericity.

In order to achieve the above object, an apparatus for producing a fluid spray metal powder according to the present invention includes an alloy melting unit for storing molten metal and having an orifice for discharging the molten metal at a lower portion thereof; Located at the lower part of the alloy melting part, the molten metal freely falls into the inside in the form of a molten metal stem through an orifice, and a plurality of gas circulation passages are installed on the bottom surface so that atmospheric gas moves from the lower part of the inner circumferential surface to the upper part, and then passes through the inner upper surface. Accordingly, a gas circulation chamber forming unit having a gas circulation chamber having an inner curved surface formed therein so as to flow and circulate downward of the central portion; It is located at the center of the lower part inside the gas circulation chamber forming part, and the upper surface is installed to maintain a predetermined distance from the inner upper surface of the gas circulation chamber forming part, and the molten metal stem that freely falls through the center has a high-speed first a first fluid injection nozzle generating fine metal droplets by injecting a fluid jet; and located at the lower end of the gas circulation chamber forming part, filled with the atmosphere gas, supplying the atmosphere gas to the gas circulation chamber through the gas circulation passage, and dispersing metal droplets generated by crushing the sprayed fluid and the molten metal stem. It is characterized in that it comprises a spraying chamber forming part having a spraying chamber for cooling and storing the metal powder therein.

In the fluid injection metal powder manufacturing apparatus according to an embodiment of the present invention, a suction inducing nozzle capable of lowering the pressure inside the gas circulation chamber by flowing high-speed gas upward along the inner circumferential surface is further provided at the lower end of the inner circumferential surface of the gas circulation chamber. can be provided

The device for manufacturing fluid-jet metal powder according to an embodiment of the present invention may further include a suction guide pipe capable of lowering a pressure in an inner space surrounded by the fluid jet at a lower end of the first fluid-jet nozzle.

In this case, the diameter of the suction guiding pipe may be constant or may increase or decrease while going downward.

In addition, the fluid injection metal powder manufacturing apparatus according to an embodiment of the present invention is installed in the gap between the inner upper surface of the gas circulation chamber and the upper surface of the first fluid injection nozzle, and the flow of atmospheric gas is directed along the radial direction. A gas direction control blade for controlling radially or rotatingly may be further provided.

Furthermore, the apparatus for manufacturing fluid-eject metal powder according to an embodiment of the present invention further includes a second fluid-eject nozzle between the tundish and the gas circulation chamber, or the first fluid-eject nozzle inside the gas circulation chamber. A second fluid injection nozzle may be further provided on the top of the upper and lower portions at predetermined intervals.

According to the present invention, when the fluid jet is sprayed, the internal space surrounded by the fluid jet is sealed, making it difficult to generate an internal accompanying air flow by the fluid jet, and compared to the prior art in which only the fluid jet collides with the molten metal stream to make it finer, The internal space surrounded by the fluid jet is opened to maximize the high-speed accompanying airflow generated in the vicinity of the fluid jet. The molten metal is firstly pulverized and then continuously pulverized with the high-speed fluid jet to maximize the efficiency of powder refinement. can improve

In addition, in the case of the prior art, since the fluid jets have a certain angle and collide at the apex of the cone shape, the energy of the fluid jets is greatly dissipated due to self-collision. , In the case of the present invention, since the primary crushing occurs by the high-speed accompanying air flow generated adjacent to the fluid jet, and then the grinding is sequentially performed by the fluid jet, the fluid consumption for producing powder of the same particle size can be reduced, and the accompanying air flow is circulated. It is economically advantageous to use.

Furthermore, in the prior art, since the internal space surrounded by the fluid jet is closed, molten metal droplets flow back together with the fluid jet, or the molten metal stream flowing out of the orifice is solidified and clogged frequently, resulting in poor operational stability, but in the case of the present invention Since the inner space surrounded by the fluid jet is open and the high-speed accompanying air current generated adjacent to the fluid jet can flow through the center of the fluid jet at high speed, it is possible to prevent reverse flow and orifice clogging caused by collision back pressure, thus improving operational reliability. has the advantage of increasing

In addition, in the prior art, since the fluid jet and the molten metal stream collide and pulverize in almost one area, the sphericity of the powder is not very good because the fine droplets are coalesced with each other, resulting in a problem of poor fluidity of the powder. However, in the present invention, the fluid jet The high-speed accompanying airflow generated in the vicinity crushes the molten metal stem into droplets and sends them into the fluid jet, and then secondary pulverization by the fluid jet occurs to prevent droplet coalescence, so the sphericity of the powder is excellent. .

The apparatus for manufacturing fluid-spray metal powder according to the present invention can easily manufacture spherical ultra-fine metal powder by continuously crushing molten metal stems with the accompanying air flow generated by the fluid jet and the high-speed fluid jet, and metal powder having the same diameter. It is economical because it can reduce the amount of fluid consumed in the case of manufacturing, and can circulate and use the atmospheric gas necessary for the generation of accompanying air flow, and can remarkably prevent reverse flow and orifice clogging caused by back pressure generated in the conventional powder manufacturing process. It has the advantage of increasing the reliability of operation.

1a to 1c are a vertical cross-sectional perspective view showing the internal structure of the fluid spray metal powder manufacturing apparatus according to the present invention, an enlarged cross-sectional perspective view of a gas circulation chamber and a fluid spray nozzle, and a fluid spray metal powder manufacturing apparatus including a spray chamber It is a cross-sectional perspective view of the whole.
2a to 2c are a vertical cross-sectional perspective view showing a coupling structure between a gas circulation chamber and a fluid ejection nozzle according to a first embodiment of the present invention, a perspective view of a state in which the upper surface of the fluid ejection nozzle is not removed, and a fluid ejection nozzle It is a perspective view with the upper surface of the removed.
3a to 3c are a vertical cross-sectional perspective view showing a coupling structure between a gas circulation chamber and a fluid injection nozzle according to a second embodiment of the present invention, a perspective view of a state in which the upper surface of the fluid injection nozzle is not removed, and a fluid injection nozzle It is a perspective view with the upper surface of the removed.
FIG. 4a is a graph showing the spraying speed of sujet according to the water pressure at the water spray nozzle, and FIG. 4b is a graph explaining the correlation between the speed of the accompanying air current generated in the vicinity of the high-speed fluid jet and the gas pressure in the vicinity. am.
5A and 5B respectively show a flow path of a process of sucking atmospheric gas from an injection chamber by applying a suction inducing nozzle inside the gas circulation chamber according to the present invention to reduce the pressure on the adjacent portion of the inner circumferential surface of the gas circulation chamber. This is an explanatory diagram and a partial enlarged cross-sectional view showing a path for sucking the atmospheric gas of the injection chamber into the gas circulation chamber through the suction inducing nozzle.
6A to 6D are vertical cross-sectional perspective views of a gas circulation chamber to which a suction inducing nozzle for radially flowing toward the center is applied by supplying fluid in a radial direction according to a third embodiment of the present invention, respectively, and an upper portion of a fluid injection nozzle; It is a perspective view without removing the surface, a perspective view with the upper surface of the fluid ejection nozzle removed, and a perspective view with the entire fluid ejection nozzle removed.
7A to 7D are vertical cross-sectional perspective views of a gas circulation chamber to which a suction induction nozzle for rotating and supplying a fluid tangentially according to a fourth embodiment of the present invention is applied, and the upper surface of the fluid injection nozzle is not removed. A perspective view of the state, a perspective view of the state in which the upper surface of the fluid injection nozzle is removed, and a perspective view of the state in which the entire fluid injection nozzle is removed.
8A and 8B are cross-sectional and cross-sectional perspective views of a cylindrical suction induction pipe for easily inhaling atmospheric gas into the fluid jet by reducing the pressure in the inner space surrounded by the fluid jet according to a fifth embodiment of the present invention, respectively. am.
9A and 9B are cross-sectional views and cross-sections showing a flared suction induction pipe for easily inhaling atmospheric gas into the fluid jet by reducing the pressure in the inner space surrounded by the fluid jet according to a sixth embodiment of the present invention, respectively. It is a perspective view.
10A and 10B are cross-sectional views and cross-sectional views of a hyperboloidal suction induction pipe for easily inhaling atmospheric gas into the fluid jet by reducing the pressure in the inner space surrounded by the fluid jet according to a seventh embodiment of the present invention, respectively. It is a perspective view.
11A and 11B show a radial gas direction control blade for radially controlling the flow of atmospheric gas along a radial direction and a rotary gas direction control for controlling the flow of atmospheric gas in a rotating form according to the eighth and ninth embodiments of the present invention, respectively. It is a perspective view showing the blade.
12 is a cross-sectional view showing a dual fluid injection nozzle having a second fluid injection nozzle between a tundish and a gas circulation chamber according to a tenth embodiment of the present invention and improving metal powder refinement efficiency.
13 is a double fluid injection nozzle provided with a second fluid injection nozzle at a predetermined interval above and below the first fluid injection nozzle inside a gas circulation chamber according to an eleventh embodiment of the present invention and improving metal powder refinement efficiency. is a cross-sectional view showing
14a and 14b show a system in which a second fluid injection nozzle is placed between a tundish and a gas circulation chamber according to twelfth and thirteenth embodiments of the present invention, and fluid is supplied in a radial direction so that the fluid flows in a radial direction toward the center. It is a cross-sectional perspective view showing a dual fluid injection nozzle having first and second fluid injection nozzles.
15A and 15B show that the second fluid injection nozzle is placed vertically above the first fluid injection nozzle at a predetermined interval inside the gas circulation chamber according to the fourteenth and fifteenth embodiments of the present invention, and the fluid flows in a tangential direction. It is a cross-sectional perspective view showing a dual fluid injection nozzle having first and second fluid injection nozzles for supplying and rotating fluid.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the accompanying drawings.

In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, terms specifically defined in consideration of the configuration and operation of the present invention may vary according to the intentions or customs of users and operators. Definitions of these terms should be made based on the content throughout this specification.

The apparatus for manufacturing fluid-sprayed metal powder according to the present embodiment solves various problems of the prior art by opening the inner space surrounded by the fluid jets to be injected and activating the accompanying air flow generated in the vicinity of the high-speed fluid jet, thereby solving the accompanying air flow and the fluid jet. It is a device for producing metal powder or alloy powder with improved fluid spray powdering efficiency and powder sphericity through continuous grinding action of

In the fluid spray metal powder manufacturing apparatus according to the present invention, it is possible to manufacture fine powder by maximizing the fluid spray powderization efficiency, further increasing the sphericity of the powder to be produced, and reducing the amount of fluid required for powderization. Manufacturing cost can be lowered, and operation reliability is excellent by preventing unstable phenomena such as orifice clogging during the manufacturing process.

1A to 1C are a vertical cross-sectional perspective view showing an internal structure of a fluid spray metal powder manufacturing apparatus according to the present invention, an enlarged cross-sectional perspective view of a gas circulation chamber and a fluid spray nozzle, and a fluid spray metal powder including a spray chamber. It is a sectional perspective view of the entire manufacturing equipment.

Referring to FIGS. 1A to 1C , the fluid spray metal powder manufacturing apparatus 100 according to an embodiment of the present invention is configured to store a molten metal 60 and discharge the molten metal 60 to a lower portion thereof. an alloy melting unit 10 to which the orifice 34 is mounted; It is located at the lower part of the alloy melting part 10, and its upper end is penetrated by the orifice 34 so that the molten metal 60 is free in the form of a molten metal stem 62 through the orifice 34 therein. falls, and a plurality of gas circulation passages 42 are installed at the lower end thereof so that the atmospheric gas moves from the lower part of the inner circumferential surface to the upper part and then flows along the inner upper surface to circulate downward in the center of the gas circulation chamber ( 44) inside the gas circulation chamber forming unit 50; It is located in the inner lower center of the gas circulation chamber 44, and the upper surface is installed to maintain a predetermined flow distance (H) with the inner upper surface of the gas circulation chamber forming part 40, penetrating the center a first fluid spray nozzle 50 for spraying a high-speed fluid jet 74 to the freely falling molten metal stem 62; and is located at the lower end of the gas circulation chamber forming part 40 and is filled with atmospheric gas and supplies the atmospheric gas to the gas circulation chamber 44 through the gas circulation passage 42, and the injected fluid and the It may include a spray chamber forming unit 10 having a spray chamber 11 inside to store the metal powder 66 generated by crushing the molten metal stem 62.

The alloy melting unit 10 stores the molten metal 60 in the crucible 32 provided inside the induction melting furnace 36, and an orifice 34 for discharging the molten metal 60 is installed at the bottom thereof. has been

The gas circulation chamber forming part 50 is located at the lower part of the alloy melting part 10 and has a hollow part formed to form a gas circulation chamber 44 inside the gas circulation chamber body 41, and the gas circulation chamber The through hole 45 formed at the upper end of the body 41 is penetrated by the orifice 34, and the molten metal 60 freely falls in the form of a molten metal stem 62 through the orifice 34 therein. .

A plurality of gas circulation passages 42 are installed at the lower end of the gas circulation chamber forming part 50, and atmospheric gas from the injection chamber 11 located at the lower side moves from the lower part to the upper part of the inner circumferential surface of the gas circulation chamber 44. Then, the circulation gas guide 43 protrudes so as to flow along the inner upper surface and circulate downward from the center, and the circulation gas guide 43 is provided with an inner curved surface.

A first fluid injection nozzle 50 is located at the center of the inner lower end of the gas circulation chamber 44, and the upper surface of the first fluid injection nozzle 50 is the inner upper surface of the gas circulation chamber forming part 40 and It is installed to maintain a predetermined flow interval (H), and a through hole (54) is formed in the center thereof to jet a high-speed fluid jet to the freely falling molten metal stem (62) passing through it.

The top surface of the first fluid injection nozzle 50 is curved so as to widen the gap toward the through hole 54 in the center while maintaining a predetermined flow distance H with the inner top surface of the gas circulation chamber forming part 40. Since it has a shape, the flow rate of the circulating atmosphere gas 72 is quickly induced along the upper surface of the first fluid injection nozzle 50.

The first fluid injection nozzle 50 is provided inside the annular body 51 of the first fluid injection nozzle 50 by connecting radial or tangential fluid supply pipes 53a, 53b; 53c, 53d from the outside. Fluid is supplied to the hollow part 55, and the fluid supplied to the hollow part 55 generates a high-speed fluid jet 74 at a predetermined collision angle A through the fluid injection slot 52 provided inside the lower end. spray

In the injection chamber forming part 10, the cylindrical injection chamber body 12 is connected to the lower end of the gas circulation chamber forming part 40, and the lower side of the injection chamber body 12 serves to gather the metal powder 66 to the center. A hopper 14 is connected, and a metal powder collector 18 for collecting the metal powder 66 through the passage 16 is disposed at the lower end of the hopper 14.

The injection chamber 11 formed inside the injection chamber forming unit 10 is filled with atmospheric gas, and the atmospheric gas is supplied to the gas circulation chamber 44 through the gas circulation passage 42, and the injection chamber A hopper 14 and a metal powder collector 18 are disposed below the 11 to store the sprayed fluid and the metal powder 66 generated by crushing the molten metal stem 62.

An exhaust port 19 used to exhaust atmospheric gas filled in the spray chamber 11 is connected to the cylindrical spray chamber body 12 of the spray chamber forming unit 10 .

As shown in FIG. 1B, the fluid spray metal powder manufacturing apparatus 100 according to an embodiment of the present invention determines the collision angle of the fluid jet of the first fluid spray nozzle 50 (ie, the vertex of the fluid jet 74). Angle) (A) is an important factor determining whether atmospheric gas inside the spray chamber 11 can be sucked into the center of the fluid jet 74, and back pressure inside the fluid jet 74 occurs when the angle exceeds 50°. Therefore, it is difficult to inhale the atmospheric gas, so it should be avoided. On the contrary, when the collision angle A is less than 5°, the suction ability is good, but the crushing ability of the fluid jet 74 is too small and the length of the fluid jet 74 is too long, so it is not efficient. Therefore, the collision angle (A) is preferably set in the range of 5° to 50°, preferably 10° to 40°.

In addition, when atmospheric gas flows from the outside to the inside of the gas circulation chamber 44, the flow distance H between the top surface of the first fluid injection nozzle 50 and the inside top surface of the gas circulation chamber 44 is It has a close relationship with the atmospheric gas suction ability of the fluid jet 74. If the flow interval H is too small, such as less than 3 mm, it is difficult to smoothly supply the atmospheric gas sucked into the fluid jet 74 and it is difficult to generate sufficient accompanying air flow, so it should be avoided. On the other hand, when the flow distance (H) exceeds 30mm, the airflow speed inside the flow distance (H) becomes too slow, and eventually the fluid jet (74) ) is difficult to inhale the atmospheric gas. Therefore, the flow interval (H) is preferably set in the range of 3 mm to 30 mm, preferably 5 mm to 20 mm.

The gas circulation passage 42 is formed as a plurality of through holes around a predetermined radius on the lower surface of the gas circulation chamber forming part 40, and the shape may be a circle, an ellipse, or various other shapes. The installation number of the gas circulation passages 42 can be two or more, but it is preferable to have at least four in order to secure the flow uniformity of atmospheric gas. In order to secure the flow uniformity of the atmospheric gas, it is advantageous to install a large number of the gas circulation passages 42, but if more than 30 are installed, it becomes structurally complicated and mutual flow interference occurs, which is disadvantageous in securing the uniformity of the flow of the atmospheric gas. it can be done Therefore, the number of gas circulation passages 42 installed is good in the range of 4 to 30, preferably 8 to 20.

Conventionally, when the fluid jet is sprayed, the inner space surrounded by the fluid jet is sealed, making it difficult to generate an internal accompanying airflow by the fluid jet, and only the fluid jet collides with the molten metal stream to make it finer.

As described above, in the present invention, the internal space surrounded by the jetted fluid jets 74 is opened to maximize the high-speed accompanying airflow generated in the vicinity of the fluid jets 74, thereby first pulverizing the molten metal stem 62. Then, the powder refinement efficiency can be maximized by performing secondary grinding with the high-speed fluid jet 74 continuously.

In addition, as shown in FIGS. 5A and 5B , the fluid spray metal powder manufacturing apparatus 100 according to an embodiment of the present invention transfers the atmospheric gas filling the inside of the spray chamber 11 to the gas circulation passage 42 In order to increase the suction force sucked into the gas circulation chamber 44 through), high-speed gas flows upward along the inner circumferential surface to the lower end of the inner circumferential surface of the gas circulating chamber forming part 40. A suction induction nozzle 50a capable of lowering the pressure inside the gas circulation chamber 44 to form a flow may be further provided.

Furthermore, in the apparatus 100 for manufacturing fluid spray metal powder according to an embodiment of the present invention, the first fluid spray nozzle 50 allows the inner space surrounded by the fluid jet 74 to more easily inhale the atmospheric gas. At the lower end of the fluid jet 74, suction induction pipes 68a-68c capable of lowering the pressure in the inner space may be further provided. As shown in FIGS. 8A to 10B , the shapes of the suction induction pipes 68a to 68c can be variously applied in various shapes such as a cylindrical shape, a trumpet shape, a hyperboloid shape, or by increasing or decreasing the diameter.

As shown in FIGS. 11A and 11B , the apparatus for manufacturing fluid spray metal powder according to an embodiment of the present invention controls the flow direction of the atmospheric gas when sucking and flowing the atmospheric gas into the center of the fluid jet 74. To this end, gas direction control blades 57 and 58 may be installed in the gap between the inner top surface of the gas circulation chamber forming part 40 and the top surface of the first fluid injection nozzle 50 . The gas direction control blades 57 and 58 are applied to control the flow of atmospheric gas radially along the radial direction or in a rotating form.

As shown in FIGS. 12 and 13 , the fluid spray metal powder manufacturing apparatus 100 according to an embodiment of the present invention further includes second fluid spray nozzles 80 and 80a to further improve metal powder refinement efficiency. Equipped with a dual fluid injection nozzle can be applied.

As a first method, a second fluid injection nozzle 80 may be further provided between the alloy melting unit 10 and the gas circulation chamber forming unit 40 to improve the miniaturization efficiency of the metal powder 66. As a second method, the gas circulation chamber 44 may further include second fluid injection nozzles 80a above and below the first fluid injection nozzle 50 spaced apart from each other at predetermined intervals.

Hereinafter, with reference to FIGS. 1A to 3C , the operation of the fluid spray metal powder manufacturing apparatus according to an embodiment of the present invention will be described in more detail.

In the case of the prior art, since the inner space surrounded by the fluid jet is sealed, the flow of air in the inner space surrounded by the fluid jet descends along the surface of the fluid jet and rises along the molten metal stem to hover in place. Therefore, if the fluid jet collision angle is slightly increased or the flow rate is increased, upward back pressure is generated, which may cause frequent operation accidents.

In the present invention, as shown in FIG. 1A, the inner space surrounded by the fluid jet 74 is opened, and the atmospheric gas is induced to be transferred from the spray chamber 11 to the inside of the gas circulation chamber 44, and the inside of the fluid jet 74 After sucking into the center of the fluid jet, it is finally circulated into the original injection chamber 11 to solve many problems caused by the internal sealing of the fluid jet of the prior art.

In order to realize this, in the case of the present invention, a gas circulation chamber forming part 40 is provided between the lower end of the alloy melting part 10 and the upper end of the injection chamber forming part 10. The top center of the gas circulation chamber forming part 40 is penetrated by the orifice 34 mounted at the bottom of the alloy melting part 10, and the molten metal 60 is formed at the center of the gas circulation chamber 44 by the orifice ( 34), it can freely fall in the form of a molten metal stem (62). A plurality of gas circulation passages 42 are installed at the lower end of the gas circulation chamber forming part 40 so that the atmospheric gas filled in the injection chamber 11 can be sucked into the gas circulation chamber 44 .

Atmospheric gas sucked into the injection chamber 11 flows from the lower part of the inner circumferential surface of the gas circulation chamber forming part 40 to the upper part, changes direction, flows along the inner upper surface, and then circulates downward from the center of the first fluid jet A curved surface is set inside the upper surface of the nozzle 50 . At this time, the first fluid injection nozzle 50 is located at the bottom center of the inside of the gas circulation chamber forming part 40, and its upper end surface is at a predetermined flow distance from the inner upper surface of the gas circulation chamber forming part 40. (H), and a high-speed fluid jet 74 is sprayed to the molten metal stem 62 that freely falls through the center.

Atmospheric gas sucked into the gas circulation chamber 44 from the ejection chamber 11 is attracted by the ejected high-speed fluid jet 74 to create an entrainment flow 72, and this entrainment flow 72 As a result, the pressure decreases along the center of the first fluid injection nozzle 50. As a result, due to the lowered pressure in the center of the first fluid spray nozzle 50, a suction force that sucks the falling molten metal stem 62 is generated between the orifice 34 and the first fluid spray nozzle 50, causing the molten metal droplets to drop. There is almost no phenomenon in which the molten metal 64 flows backward along with the fluid jet 74 or the molten metal stream 62 flowing out of the orifice 34 is solidified and clogged, so the operation stability is remarkably improved.

The manufacturing process and operation principle of the metal powder in the fluid spray metal powder manufacturing apparatus according to the present invention will be described as follows.

First, a molten metal 60 is prepared in the crucible 32 of the alloy melting unit 10, and an atmosphere gas such as nitrogen (N ₂ ) or argon (Ar) gas is filled into the injection chamber 11. The molten metal 60 flows out in the form of a molten metal stream 62 through the orifice 34 and freely falls through the center of the gas circulation chamber forming part 40 and the first fluid spray nozzle 50 . At this time, the high-speed fluid jet 74 is jetted from the first fluid jet nozzle 50 toward the molten metal stem 62, and liquid or gas may be used as the jetting fluid.

Industrial water, clean water, electrolytic water, water + alcohol mixed water, water + rust inhibitor mixed water, or oil may be used as the liquid type fluid, and nitrogen (N ₂ ), argon (Ar) or helium ( An inert gas such as He), a mixed gas such as nitrogen + hydrogen, or air may be used.

When the fluid jet 74 is ejected at a high speed, the atmospheric gas is pulled together from the surface of the fluid jet 74 to generate an entrainment flow 72 . If the speed of the fluid jet 74 is high, the speed of the accompanying air flow 72 increases proportionally, and if the speed of the accompanying air flow 72 is high, the atmospheric gas pressure in the surrounding area is lowered. As such, when the pressure in the inner space surrounded by the fluid jets 74 is lower than the pressure inside the ejection chamber 11, a suction force to draw the atmospheric gas inside the ejection chamber 11 to the gas circulation chamber 44 is generated. As a result, the atmospheric gas flows from the injection chamber 11 through the gas circulation passage 42 into the gas circulation chamber 44 and then into the inner space surrounded by the fluid jet 74 to change into a high-speed accompanying air flow 72. do.

In the present invention, the atmospheric gas is moved from the injection chamber 11 through the gas circulation passage 42 to the inside of the gas circulation chamber 44 by the accompanying air flow 72, and then the internal space surrounded by the fluid jet 74 Atmospheric gas flow 70 flowing to and changing to high-speed entrained air flow 72 may be indicated by an arrow.

The high-speed accompanying air flow 72 formed by the atmospheric gas flow 70 primarily crushes the molten metal stem 62, and subsequently the fluid jet 74 blows through the molten metal stem 62 and one of the molten metal stems 62. It collides with the primary pulverized material to be secondary pulverized into fine metal droplets 64 . In particular, since the accompanying airflow 72 scatters the molten metal stem 62 in the form of fine droplets over a wide area, when the fluid jet 74 and the scattered molten metal droplets 64 collide thereafter, the coalescence of the fine droplets is remarkably reduced. The shape of the final metal powder 66 is close to a spherical shape, and the particle size of the metal powder 66 can also be reduced.

The accompanying airflow 72 is injected into the injection chamber 11 together with the fluid jet 74, and the accompanying airflow 72 returns to the atmosphere gas filling the injection chamber 11. Since the atmospheric gas flows back to the gas circulation chamber 44 and continuously circulates in order to continuously generate the accompanying airflow 72, there is an advantage in that the powder manufacturing cost is lowered. If the fluid jet 74 is a gas jet, it joins the atmospheric gas, and if the fluid jet 74 is a liquid jet, it falls to the lower part of the injection chamber forming part 10 and is stored.

The fluid supply form in the first fluid injection nozzle 50 can be divided into two types as follows.

First, as in the first embodiment shown in FIGS. 2A to 2C, a pair of fluid supply pipes 53a and 53b are radially connected to the annular body 51 of the first fluid spray nozzle 50 to discharge fluid into an annular shape. It is supplied to the hollow part 55 in the center direction. That is, when the fluid is radially supplied to the annular hollow part 55 through the pair of fluid supply pipes 53a and 53b to flow in the radial direction toward the center, the fluid jet 74 through the annular fluid ejection slot 52 is the case when is injected.

Second, as in the second embodiment shown in FIGS. 3A to 3C, a pair of fluid supply pipes 53c and 53d are tangentially connected to the annular body 51 of the first fluid spray nozzle 50 to discharge the fluid into an annular shape. This is the case of supplying the hollow part 55 in a tangential direction to cause rotational flow.

The first embodiment type is the most general method in which the molten metal stream 62 is collided with a predetermined collision angle and crushed into metal droplets 64 .

In the second embodiment type, since the fluid jets 74 rotate and flow toward the collision point, when the fluid is a liquid, the fluid jets 74 do not finally collide with each other due to the effect of centrifugal force and can spread in a trumpet shape. . In this case, since the droplets scattered by the accompanying airflow 72 are pulverized by the rotating fluid jet 74, the probability of coalescence of the metal droplets 64 is very small, and thus a more spherical metal powder 66 is manufactured. can do.

FIG. 4A is a graph showing the ejection speed of the suze jet when the fluid jet 74 ejected from the first fluid ejection nozzle 50 is a water jet, and FIG. It is a graph explaining the correlation between the velocity of the airflow 72 and the gas pressure in the vicinity.

As an example of spraying with reference to FIG. 4A, when the water pressure is 600 bar, the speed of the suzzet jetted from the first fluid spray nozzle 50 is about 340 m/s, and when the water pressure is 1000 bar, the first fluid spray nozzle The speed of the suzzet injected at (50) is very fast at 440 m/s. When the metal powder 66 has a diameter of 10 μm, since the pressure of 1000 bar of water is applied, the speed of the accompanying air flow 72 generated in the vicinity of the sprayed suzzet can also be expected to be very high. When the velocity of the accompanying airflow 72 increases, the gas pressure around it decreases.

Figure 4b shows the correlation between the nitrogen gas velocity and the nitrogen gas pressure injected from the first fluid injection nozzle 50. When the speed of the accompanying air flow 72 is 300 m/s, it can be seen that the gas pressure becomes 0.6 bar and a suction force of 40 kPa is generated.

In this way, when the suction power is increased by reducing the gas pressure inside the gas circulation chamber 44, it is possible to maximize the effect of miniaturization, sphericalization, and improvement of operational stability of the metal powder 66 by the circulating flow of the atmospheric gas.

5a and 5b respectively apply a suction induction nozzle 50a to the inside of the gas circulation chamber 44 according to the present invention to reduce the pressure on the adjacent portion of the inner circumferential surface of the gas circulation chamber 44, thereby reducing the injection chamber 11 Explanatory diagram showing and explaining the flow path in the process of inhaling the atmospheric gas in and partially enlarged showing the path of inhaling the atmospheric gas of the injection chamber 11 into the gas circulation chamber 44 through the suction inducing nozzle 50a. it is a cross section

5A and 5B, in the fluid injection metal powder manufacturing apparatus according to the present invention, the suction inducing nozzle 50a is used by using the Coanda Effect to lower the gas pressure inside the gas circulation chamber 44. A is installed on the lower part of the inner circumferential surface of the gas circulation chamber forming part 40.

As shown in FIG. 5B, the suction inducing nozzle 50a forms an annular hollow part 48 at the lower part of the inner circumferential surface of the gas circulation chamber forming part 40, and the suction inducing gas injected from the hollow part 48 ( A slot 49 facing the inner circumferential surface of the gas circulation chamber 44 is connected to the hollow portion 48 so that 76) flows along the inner circumferential surface of the gas circulation chamber 44 . The slot 49 is formed as the extension protrusions 47 extend from the bottom plate 46 of the gas circulation chamber forming part 40 at intervals along the inner circumferential surface of the gas circulation chamber 44 .

As shown in FIGS. 6A to 6D and 7A to 7D , the hollow part 48 induces suction same as the atmospheric gas from the outside of the gas circulation chamber forming part 40 through the gas supply pipes 56a and 56b. Gas 76 is supplied at high pressure.

The Coanda effect refers to a phenomenon in which the fluid flows along the curvature of the curved surface instead of flowing in a straight line when the fluid flows in contact with the curved surface. .

When the suction inducing gas 76, which is the same as the atmospheric gas, flows along the inner circumferential surface of the gas circulation chamber 44 at high speed from the suction inducing nozzle 50a, the suction inducing gas 76 follows the curvature of the inner circumferential surface by the Coanda effect. It flows upwards, then along the horizontal upper surface, and finally downwards in the center. At this time, due to the gas flow of the ejected high-speed suction induction gas 76, the pressure is lowered in the surrounding area and the atmospheric gas filling the inside of the injection chamber 11 has a relatively high pressure, so that the gas circulation chamber ( 44) is pulled up.

By designing to optimize the Coanda effect, the injection chamber 11 can suck in a flow rate of atmospheric gas up to 15 times higher than the gas amount of the suction inducing gas 76 ejected from the original suction inducing nozzle 50a. In this way, the atmospheric gas of a rich flow rate from the injection chamber 11 is combined with the suction induction gas 76 ejected from the suction induction nozzle 50a and sent to the inner space of the fluid jet 74, and the surface portion of the fluid jet 74 Since a large amount of high-speed accompanying airflow 72 is generated in the powder micronization efficiency can be further improved.

Even when the suction induction nozzle 50a is applied, the fluid supply form from the first fluid injection nozzle 50 is to supply the fluid in the radial direction as shown in FIGS. 6A to 6D, or FIGS. 7A to 7D. As shown in, a method of supplying fluid in a tangential direction can be applied.

The same members in the third and fourth embodiments shown in FIGS. 6A to 6D and 7A to 7D have the same parts as those in the first and second embodiments shown in FIGS. 2A to 2C and 3A to 3C Numbers are given and detailed descriptions thereof are omitted.

8A and 8B show a cylindrical suction induction pipe for easily inhaling atmospheric gas into the fluid jet 74 by reducing the pressure in the inner space surrounded by the fluid jet 74 according to the fifth embodiment of the present invention, respectively. 9a and 9b respectively show a flared suction induction pipe according to the sixth embodiment of the present invention, and FIGS. 10a and 10b respectively show a hyperbolic suction induction pipe according to the seventh embodiment of the present invention. .

Referring to FIGS. 8A to 10B , when the fluid jet 74 is ejected, when the suction guide pipes 68a-68c are installed at the lower end of the first fluid injection nozzle 50, the inside surrounded by the fluid jet 74 It can reduce the pressure in space. When the pressure in the inner space of the fluid jet 74 decreases, the suction force for sucking the molten metal stem 62 into the fluid jet 74 increases, thereby improving operational stability. At the same time, the speed of the accompanying air current 72 drawn by the fluid jet 74 is also accelerated, resulting in droplets being refined, and the back pressure caused by the collision of the fluid jet 74 can be pushed downward, thereby improving operation stability and droplet refinement. A mixed synergistic effect appears.

The cross-sectional shapes of the suction guiding pipes 68a to 68c include a cylindrical suction guiding pipe 68a, a trumpet-shaped suction guiding pipe 68b, and a hyperbolic suction guiding pipe 68c as in the fifth to seventh embodiments, respectively. It is representative, and in addition, various shapes can be applied by keeping the diameter of the suction induction pipe constant or increasing or decreasing while going downward.

As shown in FIGS. 8A and 8B, the cylindrical suction induction pipe 68a is the most common type, and the smaller the diameter and the longer the length, the more advantageous the pressure reduction inside the fluid jet 74 is, and the fluid jet ( 74), it is necessary to minimize the diameter and increase the length in consideration of the collision.

In order to avoid collision with the fluid jet 74, it is necessary to apply a flared suction guide pipe 68b, as shown in Figs. 9A and 9B. In particular, when the fluid is gas, since high-pressure gas is sprayed and expands, the inclination angle of the trumpet must be determined in consideration of such volume expansion.

As shown in FIGS. 10A and 10B, the shape that most perfectly guides the flow of the fluid jet 74 and can expect a low pressure is the hyperboloidal suction induction pipe 68c. It is narrowed along the fluid jet 74 and expands near the collision part of the fluid jet 74 to reduce the pressure inside the fluid jet 74 and to protect the shape of the fluid jet 74 from being distorted. There is a difficult problem in determining the minimum diameter on the side and the diameter by vertical position.

2a to 2c, 3a to 3c, 6a to 6d and 7a to 7d, in the present invention, the fluid is supplied to the first fluid injection nozzle 50 in the radial direction, or The fluid jet 74 sprayed by supplying the fluid in a tangential direction has a linear downward flow or a rotational downward flow so as to pulverize the molten metal stem 62. If atmospheric gas is supplied to the center of the first fluid jet nozzle 50 according to the flow form of the fluid jet 74, it is advantageous to increase the speed of the accompanying air flow 72.

In the present invention, as shown in FIGS. 11A and 11B , the flow of atmospheric gas is controlled in the interval between the upper inner surface of the gas circulation chamber forming part 40 and the upper surface of the first fluid injection nozzle 50. To do this, gas direction control blades 57 and 58 are installed.

In the first method, as in the eighth embodiment shown in FIG. 11A, a plurality of gas direction control blades ( 57) is formed radially. In this case, it is possible to control the radial gas direction control blade 57 to uniformly flow the atmospheric gas in a radial direction.

In the second method, as in the ninth embodiment shown in FIG. 11B, a plurality of gas direction control blades ( 58) in a rotational form. In this case, it is possible to control the atmospheric gas to flow uniformly in a rotating form by means of the rotary gas direction control blade 58 .

In the present invention, in order to further refine the metal powder, a dual fluid injection nozzle can be applied, and two methods are possible as follows.

As in the tenth embodiment shown in FIG. 12, the first is to further provide a second fluid injection nozzle 80 between the alloy melting unit 10 and the gas circulation chamber forming unit 40, and the second is to As in the 11th embodiment shown in 13, the gas circulation chamber 44 is further provided with second fluid injection nozzles 80a above and below the first fluid injection nozzle 50 at predetermined intervals. is to do

Referring to FIG. 12, the first method will be universally used because it is the easiest to apply in the field like the tenth embodiment. However, as in the eleventh embodiment of FIG. 13 , in order to prevent solidification of the molten metal flowing out of the orifice 34 , there may be an alloy system in which an induction heating device 86 is used on the outer diameter of the orifice 34 . In this case, it is difficult to apply the first method due to space limitations, and it is much easier to apply the second method.

In addition, referring to FIG. 13, the fluids used in the first fluid injection nozzle 50 and the second fluid injection nozzle 80 may be the same or different, and high-pressure water is applied to the first fluid injection nozzle 50. It is most effective to apply high-pressure nitrogen gas to the two-fluid injection nozzle 80.

In this case, by the injection of the first fluid jet 74 and the second fluid jet 78 to the central part of the gas circulation chamber 44, the outer part of the gas circulation chamber 44 is compared to the injection chamber 11. As a relatively low pressure state is formed, negative pressure is generated. Therefore, a pressure difference between the outer part and the central part of the gas circulation chamber 44 is generated by the injected first fluid jet 74 and the second fluid jet 78, and the injected first fluid jet 74 And since the accompanying air flow 72 flowing from the periphery to the center of the gas circulation chamber 44 is generated along the second fluid jet 78, the atmospheric gas suction power is doubled. As a result, primary pulverization by the second fluid jet 78, secondary pulverization by the subsequent entrained air flow 72, and finally tertiary pulverization by the first fluid jet 74 occur, resulting in very fine metal droplets ( 64) is produced and solidified into metal powder 66.

Even when the dual fluid injection nozzle is applied as described above, the form of supplying fluid from the first fluid injection nozzle 50 is shown in the twelfth and thirteenth embodiments shown in FIGS. 14a and 14b, and FIGS. 15a and 15b As shown in the 14th and 15th embodiments, a method of supplying fluid in a radial direction or supplying fluid in a tangential direction may be applied.

That is, even when the dual fluid injection nozzle is applied, the first and second fluids are supplied to the first and second fluid injection nozzles 50 and 80 in the radial direction as in the twelfth embodiment shown in FIG. 14A. The fluid supply pipes 53a and 53b are connected to the first fluid injection nozzle 50 and the fluid supply pipes 83a and 83b are connected to the second fluid injection nozzle 80, or the 13th embodiment shown in FIG. Similarly, the fluid supply pipes 53c and 53d may be connected to the first fluid injection nozzle 50 and the fluid supply pipes 83c and 83d may be connected to the second fluid injection nozzle 80 in the tangential direction.

In addition, as in the 14th embodiment shown in FIG. 15A, in the form of supplying the first and second fluids to the first and second fluid injection nozzles 50 and 80a, the fluid supply pipes 53a and 53b are radially It is connected to the first fluid injection nozzle 50 and the fluid supply pipes 83a and 83b are connected to the second fluid injection nozzle 80a, or in the tangential direction as in the 15th embodiment shown in FIG. 15B, the fluid supply pipe 53c, 53d) may be connected to the first fluid injection nozzle 50 and fluid supply pipes 83c and 83d may be connected to the second fluid injection nozzle 80a.

As described above, in the fluid spray metal powder manufacturing apparatus 100 according to the present invention, the accompanying air flow 72 generated by the fluid jet 74 and the high-speed fluid jet 74 continuously crush the molten metal stem 62. By doing so, it is possible to easily manufacture spherical ultra-fine metal powder 66, reduce fluid consumption required when manufacturing metal powder 66 of the same diameter, and atmosphere gas necessary for generating entrained air flow 72. It is economical because it can be circulated and used, and it is possible to significantly prevent reverse flow and clogging of the orifice 34 due to back pressure occurring in the conventional powder manufacturing process, thereby increasing the reliability of operation.

<Example>

In order to manufacture SKD11 (Fe-1.5C-12Cr-1Mo-0.5V) cold-worked tool steel powder, 50 kg of SKD11 bars were melted in an induction melting furnace. The molten metal was stored in the alloy melting part at 1600 ° C, discharged through an orifice in the lower part of the crucible, and the injection chamber was filled with nitrogen gas as an atmospheric gas.

Comparative Example 1 and Comparative Example 2 applied free-fall type spray nozzles to the fluid spray nozzles used in powder manufacturing, respectively, while the fluids supplied to the spray nozzles were Comparative Example 1: nitrogen gas and Comparative Example 2: industrial water. . Examples 1 to 3 apply the fluid injection nozzle according to the present invention, and the fluid supplied to the fluid injection nozzle is Example 1: nitrogen gas, Example 2: industrial water, Example 3: (industrial water + nitrogen gas) was applied.

At this time, the inner diameter of the orifice is in the range of 4 mm to 4.5 mm, and the collision angle of each fluid injection nozzle is the same as 15 °. As the injection fluid, the pressure of nitrogen gas was 10 bar and the pressure of ultra-high pressure water was 900 bar.

Under the above conditions, metal powder was prepared while spraying the fluid according to Comparative Example 1 and Comparative Example 2, Examples 1 to 3, and the average diameter, apparent density, ultrafine powder recovery rate and Fluid consumption was measured and summarized in Table 1 below when the applied fluid was nitrogen gas and in Table 2 when the fluid was industrial water.

division fluid type fluid pressure
(bar) average diameter
D ₅₀ (μm) Apparent density
(g/cm) powder recovery rate
(<45μm) fluid consumption
(㎥/min) Comparative Example 1 nitrogen gas 10 112 3.77 17.0% 17.5 Example 1 nitrogen gas 10 65 3.84 33.8% 12.4

division fluid type Second fluid type fluid pressure
(bar) average diameter
D ₅₀ (μm) Apparent density
(g/cm) powder recovery rate
(<45μm) fluid consumption
(㎥/min) Comparative Example 2 industrial water 900 23 2.59 43.5% 135 Example 2 industrial water 900 16 2.86 61.5% 135 Example 3 commercial water nitrogen gas 900 12 3.05 75.8% 135

As shown in Table 1, in the case of applying nitrogen gas as the fluid, in Example 1 according to the present invention, compared to the process of Comparative Example 1, the recovery rate of powder of 17% or less of the target particle diameter size (45 μm) of the 3D printing process It increased to 34%, and the amount of injection gas used was found to have the effect of saving 5.1m ³ per minute. As described above, in Example 1 according to the present invention, despite the small gas consumption, the recovery rate of the fine powder increased, so it was shown to have superior price competitiveness in powder manufacturing.

In addition, in the case of Example 1, the apparent density increased more than the apparent density of the powder prepared according to Comparative Example 1, even though the diameter of the powder prepared was reduced. In general, the apparent density of a powder increases as the powder becomes larger or more spherical in shape. Therefore, it can be determined that the powder prepared according to Example 1 is more spherical than the powder prepared according to Comparative Example 1. In conclusion, the powder of Example 1 was found to be very economical because the powder size was finer and the shape was more spherical compared to the powder prepared in Comparative Example 1, and the gas consumption to achieve this was small.

As shown in Table 2, when compared to Comparative Example 2 in the case of applying ultra-high pressure industrial water to the fluid, Example 2 according to the present invention increases the recovery rate of powder with an ultra-fine particle diameter of 20 μm or less from 43% to 61% It can be seen that in Example 3, in which the dual fluid injection nozzle is applied, the powder recovery rate increases to 75%. As such, Example 2 and Example 3 have the advantage of having superior price competitiveness in the production of ultra-fine powder because the recovery rate of the ultra-fine powder increases under the same fluid pressure and fluid usage conditions.

In addition, in the case of Example 2 and Example 3, despite the decrease in the average diameter of the powder prepared, the apparent density was found to increase more than the apparent density of the powder prepared in Comparative Example 2. In general, the apparent density of a powder increases as the powder becomes larger or more spherical in shape. Therefore, it can be determined that the powder prepared according to Example 3 is more spherical than the powder prepared according to Comparative Example 2. In conclusion, the powder of Example 3 is very economical because the powder size is finer than the powder prepared according to Comparative Example 2, the sphericity is increased, and the ultra-fine powder recovery rate is improved.

In the above, the present invention has been shown and described as specific preferred embodiments, but the present invention is not limited to the above embodiments and is common knowledge in the art to which the present invention belongs within the scope of not departing from the spirit of the present invention. Various changes and modifications will be possible by those who have

The present invention utilizes the accompanying air flow generated in the vicinity of the fluid jet when the fluid is jetted at high speed to primarily pulverize the metal molten metal stem and continuously refine it again by the fluid jet, thereby improving the efficiency of fluid spray powdering and the sphericity of the powder. It can be used to manufacture fluid spray metal powder that can improve

10: injection chamber forming unit 11: injection chamber
12: injection chamber body 18: metal powder collection unit
19: exhaust port 30: alloy melting part
32 crucible 34 orifice
36: induction melting furnace 40: gas circulation chamber forming unit
42: gas circulation passage 44: gas circulation chamber
45: through hole 50: first fluid injection nozzle
53a-53d: fluid supply pipe 57,58: gas direction control blade
50a: suction induction nozzle 60: molten metal
62: molten metal stem 64: metal droplet
66: metal powder 68a-68c: suction induction pipe
70: Atmosphere gas 72: Entrained air flow
74,78: fluid jet 76: suction inducing gas
80,80a: second fluid injection nozzle 83a-83d: fluid supply pipe

Claims (13)

an alloy dissolution part for storing molten metal and having an orifice for discharging the molten metal at a lower portion thereof;
Located at the lower part of the alloy melting part, the molten metal freely falls into the inside in the form of a molten metal stem through an orifice, and a plurality of gas circulation passages are installed on the bottom surface so that atmospheric gas moves from the lower part of the inner circumferential surface to the upper part, and then passes through the inner upper surface. Accordingly, a gas circulation chamber forming unit having a gas circulation chamber having an inner curved surface formed therein so as to flow and circulate downward of the central portion;
It is located at the center of the lower part inside the gas circulation chamber forming part, and the upper surface is installed to maintain a predetermined distance from the inner upper surface of the gas circulation chamber forming part, and the molten metal stem that freely falls through the center has a high-speed first a first fluid injection nozzle generating fine metal droplets by injecting a fluid jet; and
It is located at the lower end of the gas circulation chamber forming part and is filled with the atmosphere gas, supplies the atmosphere gas to the gas circulation chamber through the gas circulation passage, and cools the sprayed fluid and metal droplets generated by crushing the molten metal stem. Fluid spraying metal powder manufacturing apparatus including a spraying chamber forming unit having a spraying chamber for storing the metal powder therein. According to claim 1,
Fluid injection metal powder manufacturing apparatus further comprising a suction inducing nozzle for lowering the pressure inside the gas circulation chamber by sending a high-speed gas flow upward along the inner circumferential surface at the lower end of the inner circumferential surface of the gas circulation chamber. According to claim 1,
A fluid injection metal powder manufacturing apparatus further comprising a suction guide pipe capable of lowering a pressure in an inner space surrounded by the first fluid jet at a lower end of the first fluid injection nozzle. According to claim 3,
The suction induction pipe is a fluid injection metal powder manufacturing device whose diameter is constant or increases or decreases while going downward. According to claim 1,
A gas direction control blade installed in the gap between the upper inner surface of the gas circulation chamber and the upper surface of the first fluid injection nozzle and for controlling the flow of the atmospheric gas radially or in a rotating manner along the radial direction Fluid injection metal powder manufacturing apparatus further comprising. According to any one of claims 1 to 5,
and a second fluid injection nozzle disposed between the alloy melting unit and the gas circulation chamber forming unit to generate fine metal droplets by spraying a second fluid jet to the molten metal stem. According to claim 6,
The second fluid injected from the second fluid injection nozzle is the same high-pressure water or high-pressure gas as the first fluid injected from the first fluid injection nozzle. According to any one of claims 1 to 5,
A fluid further comprising a second fluid jet nozzle inside the gas circulation chamber, which sprays a second fluid jet to the molten metal stem at predetermined intervals above and below the first fluid jet nozzle to generate fine metal droplets. Spray metal powder manufacturing equipment. According to any one of claims 1 to 5,
When the first fluid is ejected from the first fluid jet nozzle at high speed, the molten metal stem is primarily pulverized by utilizing the entrainment flow generated in the vicinity of the first fluid jet, and continuously fed into the first fluid jet. Fluid spraying metal powder manufacturing apparatus that is re-miniaturized by According to any one of claims 1 to 5,
The fluid jet metal powder manufacturing apparatus wherein the fluid jet collision angle of the first fluid jet nozzle, which is defined as the apex angle of the fluid jet, is set in the range of 5 ° to 50 °. According to any one of claims 1 to 5,
The flow interval (H) between the upper surface of the first fluid injection nozzle and the inner upper surface of the gas circulation chamber is set in the range of 3 mm to 30 mm fluid injection metal powder manufacturing apparatus. According to any one of claims 1 to 5,
When the first fluid jet is injected at high speed, the atmospheric gas is drawn together from the surface of the first fluid jet to generate an entrainment flow, and the pressure in the inner space surrounded by the first fluid jet is increased inside the injection chamber. When the pressure is lower than the pressure, a suction force is generated to draw the atmospheric gas inside the injection chamber into the gas circulation chamber, and the atmospheric gas is sucked into the gas circulation chamber from the injection chamber through the gas circulation passage, and then the inside surrounded by the first fluid jet. It flows into space and turns into a high-speed accompanying air flow, which primarily crushes the molten metal stem, and subsequently, the first fluid jet collides with the molten metal stem and the first pulverized material of the molten metal stem to form a second fine metal droplet. Fluid spray metal powder manufacturing device for grinding. According to claim 8,
The molten metal stem undergoes primary crushing by the second fluid jet, secondary crushing by the subsequent accompanying air flow, and finally third crushing by the first fluid jet to generate fine metal droplets to form metal powder. Fluid injection metal powder manufacturing device.

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