JPWO2019160154A1 - Metal powder manufacturing equipment and metal powder manufacturing method - Google Patents

Abstract

In the metal powder manufacturing apparatus, a supersonic combustion flame is intensively injected from a combustion flame injection port onto a supply means for hanging the molten metal and a molten metal hanging from the supply means, and the concentrated combustion flame is made into an ejected focused flow directly underneath. It has a combustion flame injection means for ejecting the combustion flame, and a stabilizing member for stabilizing the atmosphere around the upstream portion of the ejection focusing flow.

Description

The present disclosure relates to a metal powder production apparatus for producing a metal powder, and a method for producing a metal powder.

As a method for producing a metal powder, an atomizing method is known in which molten metal is dripped, pulverized into droplets, and the droplets are cooled to form a metal powder. Further, as the atomizing method, a gas atomizing method of pulverizing with high-pressure gas and a water atomizing method of pulverizing with high-pressure water are known.

Further, as a kind of gas atomizing method, a combustion flame gas atomizing method in which a molten metal is pulverized by a supersonic combustion flame is known (for example, Japanese Patent Application Laid-Open No. 2014-136807, International Publication No. 2012-157733). It is known that the combustion flame gas atomizing method can pulverize molten metal into fine droplets and can form a finer metal powder than the usual gas atomizing method.

In the combustion flame gas atomizing method described in Patent Documents 1 and 2, the concentratedly injected combustion flame becomes an ejected focused flow of a supersonic gas flow and is ejected directly below from the concentrated point. At that time, an air flow that follows the gas flow is formed around the upstream part of the eruption-focused flow, but because the eruption-focused flow has supersonic speed, a negative pressure portion, that is, around the upstream part of the eruption-focused flow. , The part where the atmospheric pressure is lower than the surroundings is likely to occur.

In particular, in a "confined type" metal powder manufacturing apparatus that hangs molten metal on the lower end of a hollow pipe and injects a combustion flame along the outer circumference of the lower end, the combustion flame injection means is placed above the ejection focusing flow. Since it is blocked, a negative pressure portion is likely to be generated around the upstream portion of the ejected focusing flow.

Such a negative pressure portion attracts the ejected focused flow and repeats generation and disappearance, which may cause the ejected focused flow to fluctuate. That is, the generation of the negative pressure portion may cause the ejected focused flow to fluctuate, resulting in turbulent flow. As a result, the pulverization of the molten metal becomes unstable, the particle size distribution of the formed metal powder becomes poor, and the desired particle size distribution may not be obtained.

Therefore, an object of the present disclosure is to provide a metal powder manufacturing apparatus and a metal powder manufacturing method capable of suppressing the fluctuation of the spouting and focusing flow to obtain a stable spouting and focusing flow.

In the metal powder manufacturing apparatus according to the first aspect, the supersonic combustion flame is intensively injected from the combustion flame injection port into the supply means for hanging the molten metal and the molten metal hanging from the supply means, and the concentrated combustion is performed. It has a combustion flame injection means that makes a flame into an ejected focused flow and ejects it directly below, and a stabilizing member that stabilizes the atmosphere around the upstream portion of the ejected focused flow.

According to the metal powder manufacturing apparatus according to the first aspect, the generation of negative pressure can be suppressed around the upstream portion of the ejection focusing flow, the fluctuation of the ejection focusing flow is suppressed, and a stable ejection focusing flow is obtained. Can be done. This makes it possible to obtain a metal powder production apparatus capable of stably pulverizing the molten metal, that is, forming a metal powder having a fine size and a good particle size distribution.

The "upstream part of the eruption-focused flow" referred to here is a part where supersonic combustion flames are concentrated to form an eruption-focused flow, and is a part including a supersonic combustion flame portion immediately before concentration. Means. Further, the stabilization of the atmosphere specifically means that the generation of the negative pressure portion is suppressed, the fluctuation of the pressure in the atmosphere is suppressed, and the like.

The metal powder manufacturing apparatus according to the second aspect is the metal powder manufacturing apparatus according to the first aspect, wherein the stabilizing member has a tubular portion that allows the ejected focusing flow to pass from the upper end opening to the lower end opening, and is described above. A gap is provided between the upper end opening of the tubular portion and the combustion flame injection means, and the upper end opening is arranged around the upstream portion of the ejection focusing flow.

According to the metal powder manufacturing apparatus according to the second aspect, since the gap is provided between the upper end opening of the cylinder portion and the combustion flame injection means, the atmospheric gas around the cylinder portion is drawn into the ejection focusing flow. It is possible to form an air flow that flows around the eruption-focused flow from around the upstream portion of the eruption-focused flow to the upper end opening of the cylinder portion. As a result, the generation of a negative pressure portion can be suppressed around the upstream portion of the ejected focused flow, and a stable ejected focused flow can be obtained.

The metal powder manufacturing apparatus according to the third aspect is the metal powder manufacturing apparatus according to the first aspect, wherein the stabilizing member has a gas injection unit that injects gas around the upstream portion of the ejection focusing flow.

According to the metal powder manufacturing apparatus according to the third aspect, by injecting gas from the gas injection unit around the upstream portion of the ejection focusing flow, the airflow can flow into the vicinity of the upstream portion of the ejection focusing flow. As a result, the generation of a negative pressure portion can be suppressed around the upstream portion of the ejected focused flow, and a stable ejected focused flow can be obtained.

The metal powder manufacturing apparatus according to the fourth aspect is the metal powder manufacturing apparatus according to the first aspect, wherein the stabilizing member ejects the stabilizer from an upper end opening arranged with a gap between the stabilizer and the combustion flame injection means. It has a tubular portion through which the focused flow flows, and also has a fluid ejection port on the inner surface of the tubular portion that ejects a fluid and flows downward along the inner surface.

According to the metal powder manufacturing apparatus according to the fourth aspect, since a gap is provided between the upper end opening of the cylinder portion and the combustion flame injection means, the atmospheric gas around the cylinder portion is opened at the upper end by the flow of fluid. It is possible to draw the airflow into the cylinder portion and allow the air flow to flow around the ejection focusing flow from around the upstream portion of the ejection focusing flow to the upper end opening of the cylinder portion. As a result, the generation of a negative pressure portion can be suppressed around the upstream portion of the ejected focused flow, and a stable ejected focused flow can be obtained.

In the metal powder manufacturing apparatus according to the fourth aspect, the atmospheric gas around the cylinder portion can be drawn into the cylinder portion more strongly by the flow of the fluid, so that the position of the cylinder portion is located from the upstream portion to the downstream portion of the ejection focusing flow. It can also be placed in a position shifted to the side, that is, around the ejection focusing flow below the concentration point of the combustion flame.

The metal powder manufacturing apparatus according to the fifth aspect opens a plurality of the fluid ejection ports in the circumferential direction of the inner peripheral surface in the metal powder manufacturing apparatus according to the fourth aspect.

By using such a fluid outlet, the atmospheric gas around the cylinder is made into a spiral airflow and drawn into the cylinder, and the airflow that flows in as a spiral from around the upstream part of the ejection focusing flow to the upper end opening of the cylinder is made. Can be formed. As a result, the generation of the negative pressure portion can be further suppressed around the upstream portion of the ejected focused flow, the position of the ejected focused flow can be made constant by the spiral air flow, and the ejected focused flow can be made more stable.

The metal powder manufacturing apparatus according to the sixth aspect enables the liquid as the fluid to be ejected in the metal powder producing apparatus according to the fourth or fifth aspect.

According to the metal powder manufacturing apparatus according to the sixth aspect, the temperature of the atmospheric gas drawn into the cylinder portion can be easily lowered. This makes it possible to rapidly cool the crushed droplets with a stable ejection and focusing flow, improve the particle size distribution, and easily form an amorphous metal powder. It can be a powder manufacturing device.

Here, in the metal powder manufacturing apparatus according to the sixth aspect, the tubular portion may be tilted with respect to the ejected focusing flow, the ejected focused flow rushes into the liquid in the tubular portion, and the droplets are formed by the liquid. It may be possible to cool directly. In this case, the flow of the liquid is preferably, for example, a swirling flow in order to increase the cooling efficiency of the droplets. By doing so, it is possible to further quench the crushed droplets, improve the particle size distribution, and easily form a more amorphous metal powder. Can be a device.
If the cylinder is tilted too much, the ejection and focusing flow may become unstable. Therefore, the tilt angle is preferably kept small, and the angle is preferably within 30 degrees with respect to the ejected focusing flow.

The metal powder manufacturing apparatus according to the seventh aspect is the metal powder manufacturing apparatus according to the second or fourth aspect, wherein the stabilizer has a length from the upper end opening to the lower end opening of the tubular portion of 10 mm. It is characterized by the above.

In the metal powder manufacturing apparatus according to the seventh aspect, the length from the upper end opening to the lower end opening of the tubular portion is set to 10 mm or more, so that the particle size distribution should be made uniform as compared with the case where the length is less than 10 mm. Can be done.

The metal powder manufacturing apparatus according to the eighth aspect is the metal powder producing apparatus according to the second or fourth aspect, wherein the gap is 5 mm or more.

In the metal powder manufacturing apparatus according to the eighth aspect, since the gap provided between the upper end opening of the tubular portion and the combustion flame injection means is 5 mm or more, a predetermined particle size is compared with the case where it is less than 5 mm. It is possible to stably and efficiently produce a fine metal powder having the above.

Further, in the method for producing a metal powder according to a ninth aspect, a supersonic combustion flame is intensively injected into a drooping molten metal, the combustion flame is made into an ejection focusing flow and ejected directly below, and the ejection focusing flow is ejected. Inflow the atmosphere around the upstream part.

According to the method for producing a metal powder according to a ninth aspect, the atmosphere around the upstream portion of the ejection focusing flow is stabilized, the generation of a negative pressure portion is suppressed around the upstream portion of the ejection focusing flow, and the ejection focusing flow is suppressed. It is possible to suppress the fluctuation of the metal and to obtain a stable ejection and focusing flow. This makes it possible to obtain a method for producing a metal powder capable of stably pulverizing the molten metal, that is, forming a metal powder having a good particle size distribution.

According to the metal powder manufacturing apparatus and the metal powder manufacturing method according to the present disclosure, it is possible to form a metal powder having a stable ejection focusing flow and a fine particle size distribution. Has.

It is a conceptual diagram which shows the metal powder manufacturing apparatus which is 1st Embodiment of this invention. It is a conceptual diagram which shows the metal powder manufacturing apparatus which is 2nd Embodiment of this invention. It is a conceptual diagram which shows the metal powder manufacturing apparatus which is 3rd Embodiment of this invention. It is sectional drawing which shows the cylinder part and the nozzle of the metal powder manufacturing apparatus which is 4th Embodiment of this invention.

[First Embodiment]
The metal powder manufacturing apparatus 10 according to the first embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the metal powder manufacturing apparatus 10 of the present embodiment includes a supply means 12 for supplying the molten metal M and a combustion flame injection means 14 for crushing the molten metal M to generate droplets Mmp. There is. Then, in the metal powder manufacturing apparatus 10, the supply means 12 and the combustion flame injection means 14 are arranged in an open space (for example, in the atmosphere).

The supply means 12 includes a container 16 for storing the molten metal M, and a high-frequency coil 18 for heating and melting the metal material to form the molten metal M is arranged on the outer peripheral side of the container 16. The supply means 12 has a pouring nozzle 20 communicating with the inside of the container 16 in the center below the bottom surface of the container 16 so that the molten metal M stored inside the container 16 can hang down from the pouring nozzle 20. ing.

At the center of the combustion flame injection means 14, a conical hollow tube portion 22 located below the supply means 12 and allowing the molten metal M to hang down extends downward. Further, the combustion flame injection means 14 includes an annular combustion chamber 24 and a combustion flame injection port 28 for injecting the combustion flame 26, and the combustion flame injection port 28 is made annular to form a hollow tube portion 22. It is designed to surround the outer peripheral side.

In the combustion flame injection means 14 of the present embodiment, for example, air and kerosene, which is a hydrocarbon, are mixed and burned in the combustion chamber 24, and the combustion flame is injected downward and inward from the combustion flame injection port 28. The combustion flame 26 can be injected without a gap along the circumference of the mouth 28. The combustion flame 26 is injected at a temperature higher than the melting point of the molten metal M and as a supersonic gas flow.

Further, the combustion flame injection means 14 has a confined type configuration, and can inject the combustion flame 26 diagonally downward from the combustion flame injection port 28 below the supply means 12, and the combustion flame 26 can be injected. Surrounds the downstream Ma of the molten metal M supplied from the pouring nozzle 20, and is concentrated and injected at one location of the downstream Ma (hereinafter, referred to as a concentrated position SP where the combustion flame 26 is concentrated on the downstream Ma). I am trying to do it.

Further, the combustion flame injection means 14 can concentrate the combustion flame 26 at a uniform injection pressure without a gap along the outer periphery of the vertical stream Ma of the molten metal M supplied from the pouring nozzle 20. The injected combustion flame 26 can be concentrated and collide with the concentrated position SP of the downstream Ma.

Further, the combustion flame injection means 14 can intensively inject the combustion flame 26 at a supersonic speed, and the concentrated combustion flame 26 becomes a substantially linear ejection focusing flow 34 whose spread is suppressed and is concentrated. It is possible to eject from the position SP vertically downward.

Here, when the combustion flame 26 collides with the concentrated position SP of the downstream Ma, the molten metal M is pulverized, and a molten metal powder, that is, a droplet Mmp, which is atomized and finely divided, is generated. (Hereinafter, this pulverization is referred to as primary pulverization.) Then, the ejection focusing flow 34 containing the droplet Mmp maintains a supersonic speed or a high speed close to the supersonic speed, and is on an extension of the axis CLc of the combustion flame injection means 14. Flow down.

Since the droplet Mmp produced by the primary pulverization is a liquid having a mass, an inertial force acts and the flow velocity is slower than that of the gas ejection focusing flow 34. Therefore, the flowing droplet Mmp receives a force of being pulled and torn by the ejection focusing flow 34 having a high relative velocity in the process of flowing down, and is re-crushed and refined. (Hereinafter, this crushing is referred to as secondary crushing.)

The flow velocity and shape of the ejection focusing flow 34 are determined by, for example, the pressure in the combustion chamber 24 and the shapes of the hollow pipe portion 22 and the combustion flame injection port 28. Further, the crushing capacity is determined by the ratio of the flow of the ejected convergent flow 34 to the discharge amount of the molten metal M discharged from the hollow pipe portion 22 per unit time. That is, as the amount of molten metal M discharged with respect to the ejected convergent flow 34 increases, the crushing energy per unit volume of the molten metal M becomes smaller, and pulverization becomes insufficient.
On the other hand, the discharge amount of the molten metal M from the hollow tube portion 22 is the weight of the molten metal M due to the liquid level height and the atmospheric pressure acting on the molten metal M of the container 16 (for example, the environment in which the container 16 is placed). The air pressure in the pressure container (when the container 16 is arranged in the pressure container (not shown in FIG. 1), the air pressure in the pressure container) and the lower portion of the combustion flame injection port 28. In addition to the pressure, it is determined by the pressure (negative pressure) generated by the pull-in flow generated by the ejection of the combustion flame 26.
The pressure due to the ejection of the combustion flame 26 is the normal state in which the container 16 is emptied, a pressure sensor is arranged at the inlet of the hole 16a of the container 16 communicating with the pouring nozzle 20, and the molten metal M is discharged at the inlet. It is obtained by measuring the pressure in a non-conventional situation. This pressure is called the top pressure. However, since the top pressure generated by the ejection of the combustion flame 26 largely depends on the combustion conditions, the discharge amount of the molten metal M and the crushing energy cannot be controlled completely independently, and the ejection focusing flow 34 is controlled. Was difficult. In particular, in the manufacturing method of the present disclosure in which the combustion flame 26 is intensively injected, pulverization continues in a high temperature range for a long time, so that it is important to control the ejection focusing flow 34 that affects the secondary pulverization. The top pressure in the present embodiment can be controlled to be 1.2 times or more the top pressure when the tubular portion 36 is not provided.
Therefore, the discharge amount of the molten metal M discharged from the hollow tube portion 22 can be increased as compared with the case where the tubular portion 36 is not provided.

(Stabilizing member)
Below the combustion flame injection means 14, a tubular portion 36 having a constant diameter is arranged coaxially with the axis CLc of the combustion flame injection means 14 as a stabilizing member for stabilizing the atmosphere around the upstream portion of the ejection focusing flow 34. .. The cylinder portion 36 is arranged at a certain distance from the lower surface of the combustion flame injection means 14, and an annular gap S1 is provided between the upper end of the cylinder portion 36 and the lower surface of the combustion flame injection means 14. .. Further, the inner diameter of the tubular portion 36 is determined so as to provide an annular gap S2 between the combustion flame 26 and the ejection focusing flow 34.
The tubular portion 36 is preferably arranged between the combustion flame injection means 14 and a portion to which a gas or liquid for cooling the droplet Mmp is supplied.

As shown in FIG. 1, the length L of the tubular portion 36 is the length from the upper end opening to the lower end opening of the tubular portion 36. The length L of the tubular portion 36 is preferably 10 mm or more. If the length L is less than 10 mm, the effect of making the particle size distribution uniform by the tubular portion 36 may not be obtained. The lower limit of the length L is preferably 15 mm, more preferably 20 mm. On the other hand, the upper limit of the length L is not particularly limited, but by limiting the length to a certain length, it is possible to prevent the droplet Mmp from adhering to the lower end opening of the tubular portion 36 and solidifying.
The ejection focusing flow 34 is a substantially linear flow in which the spread is suppressed, but tends to spread slightly as the distance from the lower surface of the combustion flame injection means 14 increases. Therefore, if the tubular portion 36 is too long, the droplet Mmp contained in the spread ejection focusing flow 34 may adhere to the inner surface on the lower side of the tubular portion 36 and solidify. In this case, when the metal powder manufacturing apparatus 10 is continuously operated for a long time, the flow path area of the lower end opening gradually becomes narrower, and the effect of making the particle size distribution uniform may not be obtained. The upper limit of the length L of the tubular portion 36 is preferably 300 mm, more preferably 100 mm, further preferably 80 mm, and even more preferably 60 mm.

The inner diameter at the upper end of the tubular portion 36 (R2 in FIG. 1) communicates with the combustion chamber 24 and is the minimum diameter of the opening of the combustion flame injection port 28 formed under the combustion flame injection means 14 (FIG. 1). It is preferably 1.5 times or more that of R1). If it is less than 1.5 times, the scattered droplet Mmp adheres to the inside of the tubular portion 36 and easily solidifies. Twice or more is more preferable. Considering the general width of the ejection focusing flow 34 formed by the combustion flame injection means 14, the inner diameter R2 at the upper end of the tubular portion 36 is preferably 30 mm or more.
The upper limit of the inner diameter of the tubular portion 36 is not limited to a certain value, but if it exceeds 10 times the minimum diameter R1 of the opening, the effect of the present disclosure by arranging the tubular portion 36 may be diminished. Therefore, it is preferably 10 times or less. For example, the inner diameter R2 of the tubular portion 36 is preferably 500 mm or less.

(Action, effect)
Next, the operation and the action / effect of the metal powder manufacturing apparatus 10 of the present embodiment will be described.

In the procedure for producing the metal powder Msp by the metal powder production apparatus 10, first, the metal material is put into the container 16 and heated and melted by the high frequency coil 18 to produce the molten metal M. At that time, the hollow tube portion 22 leading from the inside of the container 16 to the combustion flame injection port 28 is closed by a valve (not shown) so that the molten metal M does not hang down from the hollow tube portion 22.

Next, the supersonic combustion flame 26 is injected from the combustion flame injection port 28 of the combustion flame injection means 14, the valve (not shown) of the container 16 is opened, and the molten metal M in the container 16 is injected from the pouring nozzle 20. It flows vertically downward as a downstream Ma.
As a result, the supersonic combustion flame 26 is intensively injected into the concentrated position SP of the downstream Ma, the supersonic combustion flame 26 collides with the concentrated position SP of the downstream Ma, and the supersonic Ma burns at supersonic speed. The collision energy of the flame 26 causes primary pulverization to generate fine atomized droplets Mmp.

In the present embodiment, the combustion flame injection means 14 can pulverize (primary pulverization) the downstream Ma while heating it with the supersonic combustion flame 26 at a high temperature, that is, while reducing the viscosity of the downstream Ma. .. Then, by intensively injecting the supersonic combustion flame 26, the downstream Ma can be crushed with the high impact energy of the supersonic combustion flame 26. As a result, the downstream Ma can be easily pulverized, and a droplet Mmp having a fine particle size can be obtained.

Then, the combustion flame 26 concentratedly injected into the concentrated position SP of the downstream Ma is made into an ejected focused flow 34 whose spread is suppressed from the concentrated position SP due to the characteristics of the supersonic gas flow, and flows down in a straight line. At that time, the droplet Mmp generated in the form of mist by the primary pulverization of the combustion flame 26 flows down vertically together with the ejection focusing flow 34 at a supersonic speed or a high speed close to it.

In the metal powder manufacturing apparatus 10 of the present embodiment, the combustion flame injection means 14 allows the droplet Mmp to flow down together with the high-temperature and high-speed ejection focusing flow 34. That is, by heating the ejection focusing flow 34, the droplet Mmp can be allowed to flow down while being reduced in viscosity, and at the same time, it can be caused to flow down by causing a relative velocity difference with the supersonic ejection focusing flow 34. As a result, the droplet Mmp can be easily secondary pulverized, and finer droplet Mmp can be produced.
The droplet Mmp pulverized by the secondary pulverization is then cooled to become a fine metal powder Msp.

By the way, when the tubular portion 36 is not provided, a negative pressure portion may be generated around the upstream portion of the ejected focusing flow 34 to create an unstable atmosphere due to the air flow stagnating, and the upstream portion of the ejected focused flow 34 may be generated. It may be attracted to the unstable negative pressure portion, and the ejected focusing flow 34 may be shaken while repeatedly generating and disappearing the negative pressure. In the combustion flame gas atomizing method, the droplet Mmp is secondarily pulverized by the supersonic ejection focusing flow 34 to make it finer. Therefore, when the ejection focusing flow 34 is unstable, the secondary pulverization causes variation and the particle size. Poorly distributed metal powder Msp may be produced.

On the other hand, in the metal powder manufacturing apparatus 10 of the present embodiment, the ejection focusing is performed from the annular gap S1 formed between the upper end of the tubular portion 36 and the lower surface of the combustion flame injection means 14 around the upper portion of the ejection focusing flow 34. By inflowing airflow C (air around the metal powder manufacturing apparatus 10) so as to draw in the flow 34, the generation of a negative pressure portion is suppressed around the upstream portion of the ejection focusing flow 34, and the ejection focusing is suppressed. The airflow around the upstream portion of the flow 34, that is, the atmosphere can be stabilized.
Further, it is preferable to form a gap (width w shown in FIG. 1) between the upper end opening of the tubular portion 36 and the lower surface of the combustion flame injection means 14. The width w of the gap is preferably 5 mm or more. As will be described later, the particle size of the metal powder Msp can be controlled. That is, fine metal powder Msp having a predetermined particle size can be mass-produced stably, efficiently and at low cost. The lower limit of the gap width w is preferably 7 mm, more preferably 10 mm.
Further, the width w of the gap is preferably 0.1 times or more the inner diameter (R2 shown in FIG. 1) at the upper end of the tubular portion 36 in the above range. If it is less than 0.1 times, the ejection focusing flow 34 may fluctuate due to the generation of the negative pressure portion, and turbulent flow may be generated, as in the case of the confined type metal powder manufacturing apparatus described above. is there. As a result, the pulverization of the molten metal M becomes unstable, the particle size distribution of the formed metal powder Msp becomes poor, and there is a possibility that a desired particle size distribution cannot be obtained.
On the other hand, if the upper limit of the width w of the gap exceeds 10 times the inner diameter R2 of the tubular portion 36, a negative pressure portion that also creates an unstable atmosphere may be generated. For example, the upper limit of the gap width w is preferably 600 mm, and the inner diameter R2 of the tubular portion 36 is preferably 600 mm or less. The upper limit is more preferably 500 mm or less, further preferably 300 mm or less, further preferably 200 mm or less, still more preferably 100 mm or less.

As a result, fluctuations can be suppressed to form a stable ejected focused flow 34, stable secondary pulverization of droplet Mmp becomes possible, and a fine metal powder Msp having a good particle size distribution can be obtained. It becomes possible.

According to the metal powder manufacturing apparatus 10 of the present embodiment, since the hollow tube portion 22 for hanging the molten metal M extends toward the combustion flame injection port 28, the molten metal M is hung from the hollow tube portion 22. The distance to the primary pulverization by the combustion flame 26 is shortened, and stable primary pulverization is achieved. Therefore, stable primary pulverization and stable secondary pulverization make it possible to obtain a metal powder Msp having a better particle size distribution.

In the metal powder manufacturing apparatus 10 of the present embodiment, water is sprayed toward the ejection focusing flow 34 below the tubular portion 36 to quench the droplet Mmp finely divided by the secondary pulverization, or to perform the secondary pulverization. The droplet Mmp finely divided by pulverization may be plunged into a water stream to quench it. This makes it possible to obtain an amorphous Msp.

Further, in the present embodiment, it is desirable that the cross section of the tubular portion 36 is circular, but the cross section is not limited to this. In the case of a non-circular shape, the inner diameter of the tubular portion 36 is a circle coaxial with the central portion of the ejected focusing flow 34 and is the minimum in contact with the inner diameter of the tubular portion 36 when viewed in the direction in which the ejected focusing flow 34 is ejected. The diameter of the circle is the inner diameter. Further, although the tubular portion 36 has a constant diameter in the axial direction, the tubular portion 36 may have a shape in which the diameter is gradually increased in one direction of the shaft.

[Second Embodiment]
The metal powder manufacturing apparatus 10 according to the second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 2, in the metal powder manufacturing apparatus 10 of the present embodiment, the gas injection unit 38 is arranged under the combustion flame injection means 14 as a stabilizing member for stabilizing the atmosphere around the upstream portion of the ejection focusing flow 34. Has been done.
The gas injection unit 38 includes a nozzle 42 that injects gas from the gas injection port 40 at the tip. The nozzle 42 of the present embodiment is formed in an annular shape so as to surround the upstream portion of the ejection focusing flow 34, and extends in the radial direction with respect to the axis of the ejection focusing flow 34. The gas injection port 40 is continuously formed in the circumferential direction. From the gas injection port 40, the gas G is ejected toward the center of the ejection focusing flow 34 in a direction orthogonal to the axis of the ejection focusing flow 34. The gas G ejected from the gas injection port 40 may be air, or may be an inert gas such as argon gas, nitrogen gas, or hydrogen gas containing no oxygen, a reducing gas, or the like.

In the present embodiment, by ejecting the gas G from the gas injection port 40 around the upstream portion of the ejection focusing flow 34, the airflow around the upstream portion of the ejection focusing flow 34 can be stabilized, and a negative pressure portion is generated. Can be suppressed more reliably.

As a result, the metal powder manufacturing apparatus 10 of the present embodiment can also suppress the fluctuation of the ejection focusing flow 34 to form a stable ejection focusing flow 34, as in the first embodiment, and can form a stable ejection focusing flow 34. Stable secondary pulverization becomes possible, and it becomes possible to obtain a metal powder Msp that is fine and has a good particle size distribution.

[Third Embodiment]
The metal powder manufacturing apparatus 10 according to the third embodiment of the present invention will be described with reference to FIG. The same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 3, in the metal powder manufacturing apparatus 10 of the present embodiment, a cylinder portion 36 and a gas injection portion 38 are provided as stabilizing members for stabilizing the atmosphere around the upstream portion of the ejection focusing flow 34.

The nozzle 42 is provided on the upper side of the tubular portion 36, and the tip portion thereof protrudes into the tubular portion 36. The tip portion of the nozzle 42 is directed downward, and the gas G can be injected from the gas injection port 40 along the hanging ejection focusing flow 34.

In the present embodiment, since the outer peripheral side of the airflow flowing along the hanging eruption focusing flow 34 is covered with the tubular portion 36, a more stable eruption focusing flow 34 can be formed.

[Fourth Embodiment]
The metal powder manufacturing apparatus 10 according to the fourth embodiment of the present invention will be described with reference to FIG. The same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 4, in the metal powder manufacturing apparatus 10 of the present embodiment, a plurality of nozzles 44 (four in the present embodiment) extending along the tangential direction of the tubular portion 36 are equal to or equal to the circumferential direction of the tubular portion 36. Arranged at intervals.

Gas G can be injected from the nozzle 44 along the inner peripheral surface of the tubular portion 36. As a result, by forming a swirling flow of the gas G so as to surround the jet focusing flow 34 inside the tubular portion 36, the drooping jet focusing flow 34 can be stably arranged at the center of the swirling flow.

[Experimental result 1]
The relationship between the length L of the tubular portion 36 and the particle size distribution of the obtained metal powder Msp is shown below.
In this embodiment, the metal powder manufacturing apparatus 10 of FIG. 1 was used.
As the molten metal M of the supply means 12, a metal having an alloy composition of FeSiCrC was used.
The minimum diameter R1 of the opening of the combustion flame injection port 28 was set to 25 mm.
The tubular portion 36 shown in FIG. 1 was used as the stabilizing member. The tubular portion 36 is made of SUS304 material and has a cylindrical shape having an inner diameter of 46 mm and an outer diameter of 50 mm. The length L from the upper end opening to the lower end opening was 20 mm, 40 mm, and 60 mm (Sample Nos. 1, 2, and 3).
The width w of the gap between the upper end opening of the tubular portion 36 and the lower surface of the combustion flame injection means 14 is No. In 1 and 2, 10 mm, No. In 3, it was set to 20 mm.
The volume distribution (median diameters: D10, D50, D90) of the particle size of the obtained metal powder Msp was measured using a laser diffraction / scattering type particle size distribution measuring device (model name MT3300) manufactured by Microtrac.
The measurement results are shown in Table 1. In addition, the numerical values of (D90-D10) / D50, which represent the variation in particle size, are also shown. This value indicates that the smaller the value, the smaller the variation.
As the length of the tubular portion 36 becomes longer, the particle size of the obtained metal powder Msp becomes larger. The numerical values of (D90-D10) / D50 are No. The numerical value of 1 (2.3) is small.
In the metal powder manufacturing apparatus 10 of the present embodiment, since the supersonic combustion flame 26 is intensively injected into the molten metal M from the combustion flame injection port 28, the apparatus tends to be large-scale, and the injection speed and the combustion temperature can be adjusted. It can be difficult. However, even in such a metal powder manufacturing apparatus 10, the particle size of the metal powder Msp can be controlled by changing the shape of the tubular portion 36. That is, fine metal powder Msp having a predetermined particle size can be mass-produced stably, efficiently and at low cost.

[Experimental result 2]
The relationship between the particle size distribution of the metal powder Msp when the width w of the gap between the upper end opening of the tubular portion 36 and the lower surface of the combustion flame injection means 14 is changed is shown below.
In this embodiment, the metal powder manufacturing apparatus 10 of FIG. 1 was used.
As the molten metal M of the supply means Msp, one having an alloy composition of FeSiCrC system was used.
The minimum diameter R1 of the opening of the combustion flame injection port 28 was set to 25 mm.
The tubular portion 36 shown in FIG. 1 was used as the stabilizing member. The tubular portion 36 is made of SUS304 material, has a circular cross section in the horizontal direction of the drawing, has an inner diameter of 60 mm at the upper end opening, and has an inner diameter of 80 mm at the lower end opening. The length L from the upper end opening to the lower end opening was set to 230 mm.
In the present embodiment, the lower end side of the tubular portion 36 is inserted into a cylindrical cooling housing (not shown) extending in the same direction as the tubular portion 36, and water is sprayed onto the ejection focusing flow 34. The structure is such that the droplet Mmp can be cooled.
The volume distribution (median diameters: D10, D50, D90) of the particle size of the obtained metal powder Msp was measured using a laser diffraction / scattering type particle size distribution measuring device (model name MT3300) manufactured by Microtrac.
The measurement results are shown in Table 2. In addition, the numerical values of (D90-D10) / D50, which represent the variation in particle size, are also shown.
In the range of the gap width w of 20 mm to 60 mm, the value of (D90-D10) / D50 tends to decrease as the gap becomes longer. That is, by changing the width w of the gap, the particle size of the metal powder Msp can be controlled, and fine metal powder Msp having a predetermined particle size can be mass-produced stably, efficiently and at low cost.

[Other Embodiments]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and it goes without saying that the present invention can be variously modified and implemented within a range not deviating from the gist thereof. Is.

In the third embodiment, the gas is injected from the nozzle 42, but a liquid such as water may be injected from the nozzle 42. As a result, the temperature of the atmospheric gas drawn into the cylinder portion 36 can be easily lowered, a stable ejection focusing flow 34 can be obtained, and the crushed droplet Mmp can be rapidly cooled, and the particle size distribution can be increased. It is possible to easily form a good and amorphous metal powder Msp.

Further, the tubular portion 36 may be arranged at an angle with respect to the ejection focusing flow 34, and the ejection focusing flow 34 may be plunged into the liquid in the tubular portion 36 so that the droplet Mmp can be directly cooled by the liquid. In this case, the liquid flow is preferably swirled, for example, like the nozzle 42 shown in the fourth embodiment, in order to increase the cooling efficiency of the droplet Mmp. By doing so, it becomes possible to further quench the crushed droplet Mmp, improve the particle size distribution, and easily form a more amorphous metal powder Msp. If the cylinder portion 36 is tilted too much, the ejection focusing flow 34 may become unstable. Therefore, the tilt angle is preferably kept small, and the angle is preferably within 30 degrees with respect to the ejection focusing flow 34.

A chamber, a suction device, or the like that sucks and collects the metal powder Msp may be arranged below the metal powder manufacturing device 10.

The disclosure of Japanese Patent Application No. 2018-026916 filed on February 19, 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims (10)

A supply means for hanging molten metal and
A combustion flame injection means that intensively injects a supersonic combustion flame from a combustion flame injection port onto the molten metal hanging from the supply means, and makes the concentrated combustion flame into an ejection focused flow and ejects it directly below.
A stabilizing member that stabilizes the atmosphere around the upstream part of the ejected focusing flow,
Has a metal powder manufacturing equipment. The stabilizing member has a tubular portion that allows the ejected focusing flow to pass through the lower end opening, and a gap is provided between the upper end opening of the tubular portion and the combustion flame injection means, and the edge of the upper end opening is defined as described above. The metal powder manufacturing apparatus according to claim 1, which is arranged around the upstream portion of the ejection focusing flow. The metal powder manufacturing apparatus according to claim 1, wherein the stabilizing member has a gas injection unit that injects gas around the upstream portion of the ejection focusing flow. The stabilizing member is arranged with a gap between it and the combustion flame injection means, and has a tubular portion that allows the ejected focusing flow to pass through the lower end opening, and ejects a fluid onto the inner surface of the tubular portion. The metal powder manufacturing apparatus according to claim 1, further comprising a fluid outlet that flows downward along the inner surface. The metal powder manufacturing apparatus according to claim 4, wherein a plurality of the fluid spouts are opened in the circumferential direction of the inner surface. The metal powder manufacturing apparatus according to claim 4 or 5, wherein a liquid can be ejected as the fluid. The metal powder manufacturing apparatus according to claim 2 or 4, wherein the stabilizing member has a length from the upper end opening to the lower end opening of the tubular portion of 10 mm or more. The metal powder manufacturing apparatus according to claim 2 or 4, wherein the gap is 5 mm or more. A supersonic combustion flame is intensively injected into the hanging molten metal, and the combustion flame is made into an eruption focusing flow and ejected directly below, and a stabilizing member for stabilizing the surrounding atmosphere is arranged upstream of the eruption focusing flow. A method for producing a metal powder that ejects the combustion flame in a state. The method for producing a metal powder according to claim 9, wherein the stabilizing member causes an air flow to flow around the upstream portion of the ejected focusing flow.

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