Metal powder manufacturing apparatus having molten metal droplet heating coil

Abstract

The present invention relates to a metal powder manufacturing apparatus having a molten metal droplet heating coil. The metal powder manufacturing apparatus according to the present invention comprises: a chamber; a guide unit mounted on the portion of the top part of the chamber through which the base material to be processed passes, so as to guide the rod-shaped base material, which is transferred downward from the top part, to be pressed into the inner space of the chamber; a heating unit provided at the lower side of the inner space of the chamber to heat the lower portion of the base material, which is being processed, when the base material descends, and thereby melt same into a liquid; and a spray unit for spraying high-pressure gas or liquid in the falling path of molten metal droplets falling from the base material being processed, and thereby atomizing the molten metal droplets. The heating unit has a main heating coil which is provided in a tapered shape wound around the path of movement of the base material, such that the inner diameter thereof gradually decreases in the downward direction, and heats the lower portion of the base material using a high-frequency induction heating technique to melt same into a liquid.

Description

Metal powder manufacturing apparatus having a molten metal droplet heating coil

[0001] The present invention relates to a metal powder manufacturing apparatus, and more specifically, to a metal powder manufacturing apparatus that produces metal powder by melting a rod-shaped workpiece using a non-contact heating method to generate a molten metal droplet and then spraying a high-pressure gas onto the molten metal droplet, wherein the workpiece is heated more efficiently and the atomization efficiency of the droplet is improved through additional heating of the molten metal droplet.

[0002] Generally, methods for manufacturing metal powder include the gas condensation method, which is produced through homogeneous nucleation and condensation in the gas phase; the mechanical grinding method, which is produced by crushing bulk metal into powder; the method of producing through chemical precipitation; the ultrasonic spraying method, which is produced by using ultrasound in the molten metal nozzle (orifice) through which the molten metal is discharged; the centrifugal method, which is produced by dropping the discharged molten metal onto a high-speed rotating disc; and the atomizing method, which is produced by spraying molten metal through a gas or fluid to pulverize (condense).

[0003] Typically, in the method of manufacturing metal powder by spraying, a method is mainly used in which a high-speed fluid or gas is continuously blown into the tapped molten metal to atomize it using the resulting shear force. Since this method produces relatively high-quality metal powder and achieves a certain level of productivity, it has been widely used recently.

[0004] Meanwhile, among commercially available metals, titanium is lighter than conventional iron, copper, or aluminum and possesses excellent strength and corrosion resistance at high temperatures. It is used in a wide range of fields, including jet engine materials, structural components for aircraft or spacecraft in the aerospace sector, heat exchanger materials in thermal or nuclear power generation, catalyst materials in the polymer chemical industry, eyeglass frames and golf club heads in the consumer goods sector, and furthermore, health products, medical devices, and medical and dental materials. The scope of its applications is on the rise. In the future, it is expected to compete with materials such as stainless steel and duralumin in terms of applications and soon surpass them.

[0005] However, titanium is processed by powder metallurgy due to physical properties such as difficult machinability and difficult cutting. Consequently, there is an increasing demand for titanium powder, particularly titanium powder with high purity and good uniformity of powder shape and particle size. However, when titanium powder is manufactured using conventional general metal powder manufacturing methods, there are problems regarding the uniformity of powder shape and particle size or economic feasibility. Furthermore, when titanium metal is melted in a crucible, the titanium reacts with the crucible, causing a significant decrease in purity.

[0006] In order to solve the above-mentioned problems, a metal powder manufacturing device capable of producing higher purity metal powder by melting a rod-shaped processing base material using a non-contact heating method and then spraying high-pressure gas has been proposed, as disclosed in Korean Registered Patent Publication No. 10-1693729 (January 2, 2017).

[0007] However, when using a conventional metal powder manufacturing device as described above, there is a problem in that effective heating is not achieved because the penetration area of ​​the electromagnetic field into the workpiece is small when heating the workpiece using an induction heating coil. Additionally, the process of heating the workpiece to create a molten metal droplet is very short in terms of time, and there is a problem in that the temperature of the molten metal droplet falling from the surface cannot be raised, thereby reducing the atomization efficiency.

[0008] Accordingly, the objective of the present invention is to provide a metal powder manufacturing apparatus having a molten metal liquid heating coil capable of overcoming the aforementioned conventional problems.

[0009] Another objective of the present invention is to provide a metal powder manufacturing apparatus capable of producing metal powder by melting a rod-shaped workpiece using a non-contact heating method to generate molten metal and then injecting high-pressure gas into the molten metal droplet, while heating the workpiece more efficiently and improving the atomization efficiency of the molten metal droplet through additional heating of the molten metal droplet.

[0010] Another objective of the present invention is to provide a metal powder manufacturing apparatus for producing high-melting-point and high-quality metal powder by additionally heating the discharged molten metal droplet.

[0011] According to an embodiment of the present invention for achieving some of the above technical problems, a metal powder manufacturing apparatus according to the present invention comprises: a chamber; a guide unit mounted in the upper part of the chamber where the workpiece passes through, guiding a rod-shaped workpiece conveyed downward from the upper part to be pressed and penetrated into the internal space of the chamber; a heating unit mounted in the lower part of the internal space of the chamber, heating the lower part of the workpiece to melt it into a liquid state when the workpiece descends; and a spraying unit that sprays high-pressure gas or liquid onto the falling path of the molten metal droplet falling from the workpiece to atomize the molten metal droplet; wherein the heating unit is provided with a main heating coil that has a coiled shape to surround the movement path of the workpiece and has a tapered shape in which the inner diameter gradually decreases as it goes downward, and heats the lower part of the workpiece to melt it into a liquid state using the principle of high-frequency induction heating.

[0012] The main heating coil is arranged along the movement path of the workpiece and is provided with an upper workpiece heating section and a lower droplet heating section. The workpiece heating section is provided with a tapered shape in which the inner diameter gradually decreases as it moves downward, and is wound to surround the movement path of the workpiece, thereby heating the lower part of the workpiece to melt it into a liquid state. The droplet heating section is extended from the bottom of the workpiece heating section and is wound to surround the molten metal droplet that falls through the workpiece heating section, and is configured to further heat the falling molten metal droplet.

[0013] The above-mentioned base material heating section has a coil structure wound such that the inner diameter gradually decreases with the same slope from the top to the bottom, and the above-mentioned droplet heating section may have a coil structure wound such that the inner diameter is equal to or smaller than the inner diameter of the lowest part of the above-mentioned molten metal heating section.

[0014] The above-mentioned base material heating section has a concave coil structure wound in a curve from the top to the bottom so that the inner diameter gradually decreases, and the above-mentioned droplet heating section may have a coil structure wound so that the inner diameter is equal to or smaller than the inner diameter of the lowest part of the above-mentioned molten metal heating section.

[0015] The above-mentioned base material heating section has a coil structure wound such that the inner diameter gradually decreases with the same slope from the top to the bottom, and the above-mentioned droplet heating section may have a double coil structure consisting of an inner coil wound to have an inner diameter equal to or smaller than the inner diameter of the lowest part of the above-mentioned base material heating section and an outer coil surrounding the inner coil.

[0016] The above-mentioned base material heating section has a concave coil structure wound in a curve from the top to the bottom, with the inner diameter gradually decreasing, and the above-mentioned droplet heating section may have a double coil structure consisting of an inner coil wound to have an inner diameter equal to or smaller than the inner diameter of the lowest part of the above-mentioned molten metal heating section and an outer coil surrounding the inner coil.

[0017] The above base material heating section may have a double coil structure.

[0018] The heating unit may further comprise a pre-heating coil arranged along the movement path of the workpiece above the main heating coil, and the pre-heating coil may have a cylindrical shape wound to surround the movement path of the workpiece and be configured to preheat the workpiece.

[0019] The above main heating coil can heat the workpiece to a temperature 150 to 200°C higher than the melting point of the workpiece.

[0020] The above main heating coil may be coated with a ceramic material to block and insulate heat radiated during the melting process of the above workpiece.

[0021] According to the present invention, a metal powder is manufactured by melting a rod-shaped workpiece using a non-contact heating method to produce a molten metal, and then spraying a high-pressure gas onto the molten metal droplet. The main heating coil is configured in a tapered shape to increase the heat generation of the workpiece, thereby improving energy efficiency, and an additional droplet heating section is formed to further heat the molten metal droplet, thereby improving the atomization efficiency of the molten metal droplet. This has the advantage of enabling the production of high-melting-point and high-quality metal powder.

[0022] FIG. 1 is a vertical cross-sectional view of a metal powder manufacturing apparatus according to one embodiment of the present invention, and

[0023] FIG. 2 is a perspective view of the heating unit of FIG. 1, and

[0024] FIG. 3 is a cross-sectional view of FIG. 2, and

[0025] FIGS. 4 to 11 are cross-sectional views illustrating various embodiments of the main heating coil of FIG. 2, and

[0026] Figures 12 and 13 are drawings illustrating the electromagnetic field penetration area of ​​a workpiece corresponding to the structure of a main heating coil.

[0027] In the following, preferred embodiments of the present invention will be described in detail with reference to the attached drawings, with no other intent than to provide a thorough understanding of the present invention to those skilled in the art to which the present invention pertains.

[0028] First, it should be noted that when assigning reference numerals to the components of each drawing, the same components are assigned the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the present invention, if it is determined that a detailed description of related known components or functions could obscure the essence of the invention, such detailed description is omitted.

[0029] Furthermore, when it is stated that one component is 'connected,' 'supported,' 'connected,' 'supplied,' 'transmitted,' or 'contacted' with another component, it should be understood that while the connection, support, connection, supply, transmission, or contact may be direct to that other component, there may also be other components present in between.

[0030] The terms used in this specification are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0031] Furthermore, it should be noted in advance that expressions such as "upper side," "lower side," and "side" in this specification are described based on the drawings, and may be expressed differently if the orientation of the object changes. For the same reason, some components in the attached drawings may be exaggerated, omitted, or schematically depicted, and the size of each component does not entirely reflect its actual size.

[0032] Additionally, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but such components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0033] The meaning of "comprising" as used in the specification is to specify certain characteristics, regions, integers, steps, actions, elements, and / or components, and does not exclude the existence or addition of other specific characteristics, regions, integers, steps, actions, elements, components, and / or groups.

[0034] FIG. 1 is a vertical cross-sectional view of a metal powder manufacturing apparatus according to one embodiment of the present invention, FIG. 2 is a perspective view of the heating unit of FIG. 1, and FIG. 3 is a cross-sectional view of FIG. 2. FIG. 4 to FIG. 11 are cross-sectional views illustrating various embodiments of the main heating coil of FIG. 2, and FIG. 12 and FIG. 13 are drawings illustrating the electromagnetic field penetration area of ​​a workpiece corresponding to the structure of the main heating coil.

[0035] As illustrated in FIGS. 1 to 3, a metal powder manufacturing apparatus according to one embodiment of the present invention comprises: a chamber (100) having an internal space of a predetermined size; a transfer unit (not shown) for downwardly transferring a workpiece (10) in the shape of a rod so that the workpiece (10) penetrates the upper part of the chamber (100); a guide unit (200) mounted on the upper part of the chamber (100) where the workpiece (10) penetrates, guiding the rod-shaped workpiece being downwardly transferred from the upper part to be pressed and penetrated into the internal space of the chamber; a heating unit (300) mounted on the lower side of the internal space of the chamber (100), heating the lower part of the workpiece (10) to melt it into a liquid state when the workpiece (10) descends; and a high-pressure gas or liquid sprayed onto the falling path of a droplet of molten metal falling from the workpiece (10) to make the droplet of molten metal It is configured to include an atomizing spray unit (400).

[0036] The guide unit (200) may include a guide tube (310) having a hollow tube shape so that the workpiece (10) can pass through downward, and a screw cap (320) that is screw-coupled to cover the upper part of the guide tube (310) and has a through hole formed therein through which the workpiece (10) can pass.

[0037] The above-described spray unit (400) is equipped with a spray nozzle (410) that sprays high-pressure gas onto a falling molten metal droplet (12) and a gas supply pipe (420) that supplies high-pressure gas to the spray nozzle (410) as basic components. Components that are essential for manufacturing metal powder but are not described below are identical to the configuration of a general metal powder manufacturing device.

[0038] The metal powder manufacturing device according to the present invention lowers the workpiece (10) and then operates the heating unit (300) to melt the surface of the workpiece (10), so that the molten metal liquid falls freely without coming into contact with any object. This fundamentally prevents the phenomenon of impurities being generated during the process of the molten metal liquid coming into contact with other objects, and thereby enables the production of high-purity metal powder.

[0039] The heating unit (300) heats the workpiece (10) using a heating coil for high-frequency induction heating to which the principle of electromagnetic induction of high-frequency current is applied, and may be composed of a free heating coil (310) and a main heating coil (320) arranged along the movement path of the workpiece (10).

[0040] The above-mentioned pre-heating coil (310) is arranged along the movement path of the workpiece (10) above the main heating coil (320), and the pre-heating coil (310) has a cylindrical shape wound to surround the movement path of the workpiece (10) and can be configured to preheat the workpiece (10). Accordingly, as the workpiece (10) passes through the interior of the pre-heating coil (310), the side of the workpiece (10) can be evenly preheated in a high-frequency electromagnetic field.

[0041] If the above-mentioned workpiece (10) is configured to be heated rapidly all at once, not only is a large amount of energy required to melt the workpiece (10), but it may also be difficult to finely control the heating temperature of the workpiece (10). In addition, in the case of a workpiece (10) having a material such as tungsten or molybdenum alloy, the amount of heat generated by the main heating coil (320) alone may be insufficient, and in the case of a workpiece (10) made of a metal material with a high heat transfer coefficient, the ratio of cooling by the surrounding environment to the amount of heat generated may be large, making it difficult to heat or generate heat of the workpiece (10). Accordingly, the heating unit (300) can heat the workpiece (10) through the main heating coil (320) while the workpiece (10) is preheated through the pre-heating coil (310) to melt it into a liquid state and generate a molten metal liquid.

[0042] Here, if a large amount of energy is not required for heating the workpiece (10) or if preheating is not required, the pre-heating coil (310) may not be provided, and the main heating coil (320) alone may constitute the heating unit (300).

[0043] The main heating coil (320) is an induction heating coil to which the principle of electromagnetic induction of high-frequency current is applied, and may be made of high-purity copper pipe to allow high-frequency current to flow well. The main heating coil (320) is integrally formed with a connecting pipe (340) for connecting to an electrode terminal (330) provided on the side of the chamber (100). The connecting pipe (340) is made of the same copper pipe material as the main heating coil (320) and may have a configuration that starts from the main heating coil (320) and extends to an electrode connection part (335) connected to the electrode terminal (300). The connecting pipe (340) is configured to connect the main heating coil (320) and the electrode terminal (330) and is configured to be wrapped and protected by a separate support pipe (350).

[0044] The main heating coil (320) may be coated with a ceramic material to block and insulate heat radiated during the melting process of the workpiece (10). Through the ceramic coating, it is also possible to prevent corona discharge or plasma phenomena that may occur electrically in a high vacuum and inert atmosphere. The ceramic material may be at least one material selected from boron nitride (Bn), alumina, and zirconia.

[0045] Meanwhile, as shown in FIG. 12 (a), the main heating coil (32) of the prior art has a cylindrical shape wound to surround the movement path of the workpiece (10), just like the free heating coil (310). In this case, the penetration area (15) into which the electromagnetic field generated by the main heating coil (32) of the prior art penetrates is very small, so the amount of heat generated is small, and it takes a long time to melt the workpiece (10) into a liquid state and more energy is consumed. This is because the lower part of the workpiece (10) has a conical or tapered structure in which the outer diameter gradually decreases as it goes downward, so when the main heating coil (32) has a cylindrical wound structure, the electromagnetic field penetrates only to the part (15) of the workpiece (10) closest to the main heating coil (32), and the electromagnetic field does not penetrate to the tapered part (the part where the inner diameter gradually decreases) because the distance is far, so the amount of heat generated is small.

[0046] In order to solve these problems and increase the penetration area of ​​the electromagnetic field, the main heating coil (320) in the present invention may have a shape that is wound to surround the movement path of the workpiece (10), as shown in FIGS. 4 and 5, and may have a tapered shape (or funnel shape, cone shape, etc.) in which the inner diameter gradually decreases as it goes downward.

[0047] For example, assuming that the workpiece (10) has a diameter of 50 mm, and assuming that the main heating coil (320) has a structure wound in 5 turns, the inner diameter (L1) of the uppermost 1 turn can be set to 60 to 62 mm, and the inner diameter of the lowermost 5 turns (L2) can be set to 17 to 19 mm, and in the case of 2 to 4 turns, the inner diameter structure can be appropriately selected such that it becomes progressively smaller from the top to the bottom. If the inner diameter of the main heating coil (320) becomes too large, the diameter of the molten metal droplet generated increases, and a problem arises in which the particle size of the generated metal powder increases. Therefore, the inner diameter of the main heating coil (320) can be appropriately selected in a direction that increases the penetration area of ​​the electromagnetic field without contacting the workpiece (10) and without increasing the particle size of the metal powder.

[0048] As shown in FIG. 4, the main heating coil (320) may have a coil structure in which the inner diameter gradually decreases with the same slope from the top to the bottom, while having a shape that surrounds the movement path of the workpiece (10). In this case, as shown in FIG. 12 (b), the lower end of the workpiece (10) is brought close to the main heating coil (320), and the penetration area (15) of the electromagnetic field is expanded compared to the case shown in FIG. 12 (a), so the amount of heat generated increases, and the time and energy required for melting the workpiece (10) can be drastically reduced.

[0049] And, as shown in FIG. 5, the main heating coil (320) may have a concave coil structure wound in such a way that the inner diameter gradually decreases as it forms a curve from the top to the bottom. That is, the main heating coil (320) may have a coil structure that forms a tapered shape with a concave curve structure from top to bottom when viewed from the outer diameter side (outer side), and a tapered shape with a convex curve structure from top to bottom when viewed from the inner diameter side (inner side). That is, compared to the structure of FIG. 4, the middle part of the main heating coil (320) forms a structure that is closer to the workpiece (10).

[0050] In this case, as shown in Fig. 12 (c), the lower part of the workpiece (10) is closer to the main heating coil (320) than in the case of Fig. 4 and Fig. 12 (b). Therefore, the penetration area (15) of the electromagnetic field is further expanded compared to the case shown in Fig. 12 (a) and Fig. 12 (b), so the amount of heat generated is higher, and the time and energy required to melt the workpiece (10) can be drastically reduced.

[0051] The lower part of the workpiece (10) can be heated to a temperature about 150 to 200°C higher than the melting temperature of the workpiece (10) through the main heating coil (320).

[0052] Meanwhile, even when a molten metal liquid is produced by heating a workpiece (10) with a main heating coil (320) as shown in FIGS. 4 and 5, some problems may occur.

[0053] Even in the case of a metal powder manufacturing device equipped with a main heating coil (320) as shown in FIGS. 4 and 5, the process of heating the workpiece (10) to create a molten metal droplet is very short in terms of time, and the molten metal droplet that melts and falls from the surface of the workpiece (10) falls without being heated separately. At this time, there is a problem that the molten metal droplet cools during the falling process, but there is a problem that the temperature of the molten metal droplet cannot be raised, which lowers the atomization efficiency.

[0054] The atomization of molten metal droplets involves a primary atomization process in which the molten metal droplets form fine droplets, and a secondary atomization process in which the primary atomized droplets break down through repeated collisions and re-division by surrounding air currents when they exceed a certain critical size. However, there is a problem in that atomization becomes difficult if the temperature of the molten metal droplets is not sufficient.

[0055] Another embodiment of the main heating coil (320) for overcoming these problems is described through FIGS. 6 to 9.

[0056] As illustrated in FIGS. 6 to 9, the main heating coil (320) has an upper base material heating section (322) and a lower droplet heating section (324). Although the main heating coil (320) is described as having an upper base material heating section (322) and a lower droplet heating section (324) as a single coil structure, it may have a two-coil structure with a first coil for base material heating and a second coil for droplet heating separated from each other as needed.

[0057] The above-mentioned base material heating section (322) is similar to the structure described in FIGS. 4 and FIGS. 5, and the above-mentioned droplet heating section (324) may have a coil structure extending from the lower side of the base material heating section (322) such that it has an inner diameter equal to or smaller than the inner diameter of the lowest part of the base material heating section (322). That is, the above-mentioned base material heating section (322) is provided with a tapered shape (or funnel shape, cone shape, etc.) in which the inner diameter gradually decreases as it goes downward, having a shape that is wound to surround the movement path of the above-mentioned base material (10), and the lower part of the above-mentioned base material (10) is heated to melt it into a liquid state, and the above-mentioned droplet heating section (324) is extended from the bottom of the above-mentioned base material heating section (322) and has a shape that is wound to surround the molten metal droplet that is melted into a liquid state and falls through the above-mentioned base material heating section (322), and additionally heats the falling molten metal droplet. Accordingly, the cooling of the falling molten metal droplet is reduced and the temperature is raised through additional heating, thereby improving the atomization efficiency in the subsequent spraying process through the above-mentioned spraying unit (400).

[0058] In the drawing, the droplet heating section (324) is configured with one coil turn, but if necessary, it is possible to increase the number of coil turns to configure it with a coil having multiple turns.

[0059] For example, assuming that the above-mentioned workpiece (10) has a diameter of 50 mm, and assuming that the main heating coil (320) has a coil structure wound in a total of 6 turns, and that turns 1 to 5 constitute the workpiece heating section (322) and the last turn 6 constitutes the droplet heating section (324), the inner diameter (L1) of the uppermost turn 1 can be set to 60 to 62 mm, and the inner diameter of the lowermost turn 5 (L2) can be set to 17 to 19 mm. In the case of turns 2 to 4, the inner diameter structure can be gradually reduced from the top to the bottom so as to increase the penetration area of ​​the electromagnetic field without contacting the above-mentioned workpiece (10).

[0060] Here, the inner diameter (L3) of the last 6 turns constituting the droplet heating section (324) may be set to 16 to 18 mm, which is the same as or slightly smaller than the inner diameter (L2) of the lowest 5 turns of the base material heating section (322). Additionally, it is possible to extend the droplet heating section (324) by winding it up to 7 turns or 8 turns with an inner diameter that is the same as or similar to the inner diameter of the coil of the 6th turn, and the inner diameter (L3) of the coil constituting the droplet heating section (324) at this time may be appropriately selected so that the electromagnetic field can penetrate into the interior of the molten metal droplet that is melted into a liquid state and falls through the base material heating section (322).

[0061] Specifically, as illustrated in FIG. 6, the base material heating section (322) of the main heating coil (320) may have a coil structure in which the inner diameter gradually decreases with the same slope from the top to the bottom, while having a shape that surrounds the movement path of the workpiece (10). Additionally, the droplet heating section (324) extends from the bottom of the base material heating section (322) and has a shape that surrounds the molten metal droplet falling through the base material heating section (322), thereby further heating the falling molten metal droplet.

[0062] In this case, as illustrated in FIG. 13 (a), the lower part of the workpiece (10) is brought close to the main heating coil (320) through the workpiece heating section (322), and the penetration area (15) of the electromagnetic field is expanded compared to the case illustrated in FIG. 12 (a), so the amount of heat generated is increased, and the time and energy required for melting the workpiece (10) can be drastically reduced. In addition, through the droplet heating section (324), the molten metal droplet (20) that is melted into a liquid state and falls through the workpiece heating section (322) is further heated. Accordingly, the cooling of the falling molten metal droplet is reduced, and the temperature is raised through additional heating, thereby improving the atomization efficiency of the metal powder during the subsequent spraying process through the spraying unit (400).

[0063] And, as shown in FIG. 7, the base material heating section (322) of the main heating coil (320) may have a concave coil structure wound in such a way that the inner diameter gradually decreases as it forms a curve from the top to the bottom. That is, the base material heating section (322) may have a coil structure that forms a tapered shape with a concave curve structure from top to bottom when viewed from the outer diameter side (outer side), and a tapered shape with a convex curve structure from top to bottom when viewed from the inner diameter side (inner side). That is, compared to the structure of FIG. 6, the middle part of the main heating coil (320) forms a structure that is closer to the workpiece (10).

[0064] In this case, as illustrated in FIG. 13 (b), the lower portion of the workpiece (10) is closer to the workpiece heating section (322) than in FIG. 6 and FIG. 13 (a). Therefore, the penetration area (15) of the electromagnetic field is further expanded compared to the case illustrated in FIG. 13 (a), so the amount of heat generated is higher, and the time and energy required for melting the workpiece (10) can be drastically reduced. Additionally, through the droplet heating section (324), the molten metal droplet (20) that melts into a liquid state and falls through the workpiece heating section (322) is further heated. Accordingly, the cooling of the falling molten metal droplet is reduced, and the temperature is raised through additional heating, thereby improving the atomization efficiency of the metal powder during the subsequent spraying process through the spraying unit (400).

[0065] FIGS. 8 and 9 illustrate a case where the droplet heating section (324) of the main heating coil (320) of FIGS. 6 and 7 has a double coil structure. Specifically, the main heating coil (320) of FIGS. 8 and 9 has a base material heating section (322) that is the same as described in FIGS. 6 and 7, and the droplet heating section (324) may have a double coil structure consisting of an inner coil (C1) wound to have an inner diameter equal to or smaller than the inner diameter of the lowest part of the base material heating section (322), and an outer coil (C2) surrounding the inner coil (C1). When the droplet heating section (324) has a double coil, it is intended to increase the coil inductance value of the droplet heating section (324) to supply more energy to the molten metal droplet (20).

[0066] Generally, the inductance value of the coil is proportional to the square of the number of coil turns, and as the inductance value increases, the penetration depth of the electromagnetic field (especially the magnetic field) increases, allowing more energy to be supplied to the molten liquid droplet (20) that falls in a liquid state through the base material heating section (322).

[0067] By utilizing this principle, as illustrated in FIGS. 10 and 11, the base material heating section (322) can also have a double coil structure. That is, both the base material heating section (322) and the droplet heating section (324) constituting the main heating coil (320) of FIGS. 6 and 7 can have a double coil structure. This also increases the inductance value of the coil, thereby increasing the penetration area of ​​the electromagnetic field (especially the magnetic field) into the processed base material (10) in the base material heating section (322) or the penetration depth, and in the droplet heating section (324), more energy can be supplied to the falling molten metal droplet (20).

[0068] As described above, according to the present invention, a metal powder is manufactured by melting a rod-shaped workpiece using a non-contact heating method to produce a molten metal, and then spraying a high-pressure gas onto the molten metal droplet. By configuring the main heating coil in a tapered shape, the amount of heat generated by the workpiece is increased to improve energy efficiency, and by additionally forming a droplet heating section, the atomization efficiency of the molten metal droplet can be improved through additional heating of the molten metal droplet. This has the advantage of enabling the production of high-melting-point and high-quality metal powder.

[0069] The description of the above-described embodiments is merely an example with reference to the drawings for a more thorough understanding of the present invention and should not be interpreted as limiting the present invention. Furthermore, it will be obvious to those skilled in the art that various changes and modifications are possible within the scope of the basic principles of the present invention without departing from them.

Claims

1. Chamber; A guide unit mounted in the upper portion of the chamber where the workpiece penetrates, guiding a rod-shaped workpiece conveyed downward from the upper portion to be pressed and penetrated into the internal space of the chamber; A heating unit mounted on the lower side of the internal space of the chamber, which heats the lower part of the workpiece to melt it into a liquid state when the workpiece descends; and A spraying unit that sprays high-pressure gas or liquid onto the falling path of a molten metal droplet falling from the workpiece to atomize the molten metal droplet; The above heating unit is, A metal powder manufacturing apparatus characterized by having a main heating coil that is wound to surround the movement path of the workpiece and has a tapered shape in which the inner diameter gradually decreases as it goes downward, and heats the lower part of the workpiece using the principle of high-frequency induction heating to melt it into a liquid state.

2. In Claim 1, The above main heating coil is, Arranged along the movement path of the above-mentioned workpiece, it is provided with an upper workpiece heating section and a lower droplet heating section, and The above-mentioned base material heating section is provided with a tapered shape having a wound shape that surrounds the movement path of the above-mentioned workpiece and a tapered shape in which the inner diameter gradually decreases toward the downward direction, thereby heating the lower part of the above-mentioned workpiece to melt it into a liquid state, and A metal powder manufacturing apparatus characterized by the above droplet heating section extending from the lowest end of the above base material heating section, having a wound shape to surround the molten metal droplet falling through the above base material heating section, and additionally heating the falling molten metal droplet.

3. In Claim 2, The above-mentioned base material heating section has a coil structure wound such that the inner diameter gradually decreases with the same slope from the top to the bottom, and A metal powder manufacturing apparatus characterized in that the above droplet heating section has a coil structure wound to have an inner diameter equal to or smaller than the inner diameter of the lowest part of the above molten metal heating section.

4. In Claim 2, The above-mentioned base material heating section has a concave coil structure wound in a curve from the top to the bottom, with the inner diameter gradually decreasing. A metal powder manufacturing apparatus characterized in that the above droplet heating section has a coil structure wound to have an inner diameter equal to or smaller than the inner diameter of the lowest part of the above molten metal heating section.

5. In Claim 2, The above-mentioned base material heating section has a coil structure wound such that the inner diameter gradually decreases with the same slope from the top to the bottom, and A metal powder manufacturing apparatus characterized in that the above droplet heating section has a double coil structure comprising an inner coil wound to have an inner diameter equal to or smaller than the inner diameter of the lowest part of the above base material heating section and an outer coil surrounding the inner coil.

6. In Claim 2, The above-mentioned base material heating section has a concave coil structure wound in a curve from the top to the bottom, with the inner diameter gradually decreasing. A metal powder manufacturing apparatus characterized in that the above droplet heating section has a double coil structure comprising an inner coil wound to have an inner diameter equal to or smaller than the inner diameter of the lowest part of the above molten heating section and an outer coil surrounding the inner coil.

7. In any one of claims 3 to 6, A metal powder manufacturing apparatus characterized in that the above-mentioned base material heating section has a double coil structure.

8. In Claim 1, The above heating unit is, A free heating coil is further provided above the main heating coil and arranged along the movement path of the workpiece, and A metal powder manufacturing apparatus characterized in that the above-mentioned preheating coil has a cylindrical shape wound to surround the movement path of the workpiece and is configured to preheat the workpiece.

9. In Claim 1, A metal powder manufacturing apparatus characterized by the above main heating coil heating the workpiece to a temperature 150 to 200°C higher than the melting point of the workpiece.

10. In Claim 1, A metal powder manufacturing apparatus characterized in that the main heating coil is coated with a ceramic material to block and insulate heat radiated during the melting process of the workpiece.

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