JP2012201939A - Apparatus and method for producing metal powder - Google Patents

Abstract

A metal powder production apparatus and a metal powder production method capable of stably producing a high-quality metal powder regardless of the composition of the metal powder to be produced.
A metal powder production apparatus (1) includes a supply unit (6), a storage unit (2) provided below the storage unit (2) for storing molten metal, a nozzle (3) provided below the storage unit (2), and a storage unit (2). The heating means 8 is provided at least on the liquid surface portion of the molten metal 90 and heats the molten metal 90. The reservoir 2 includes a reservoir container 21 and a reservoir cylindrical member 22 provided on the lower surface thereof, and an induction heating coil 81 is built in the wall of the reservoir container 21. The heating unit 8 includes the induction heating coil 81 and a control unit 82 including a power source that applies a voltage to the induction heating coil 81.
[Selection] Figure 1

Description

  The present invention relates to a metal powder production apparatus and a metal powder production method.

Conventionally, in order to produce a metal powder, a metal powder production apparatus (atomizer) for pulverizing molten metal by an atomizing method has been used. As this metal powder manufacturing apparatus, Patent Document 1 includes a container for holding molten metal, an orifice for passing molten metal flowing down from the container, and a slit for injecting a fluid jet to the molten metal passing through the orifice. And an apparatus having a nozzle. In this device, by the action of gas that passes through the orifice at high speed along with the fluid jet, the molten metal flowed down from the container is split and further made fine by colliding with the fluid jet, thereby making fine metal A powder can be produced.
However, depending on the composition of the metal powder to be produced, the metal powder has a large particle size or the metal powder has a wide particle size distribution, making it difficult to produce a fine and uniform metal powder. was there.

Japanese Patent No. 3858275

  An object of the present invention is to provide a metal powder production apparatus and a metal powder production method capable of stably producing a high-quality metal powder regardless of the composition of the metal powder to be produced.

The above object is achieved by the present invention described below.
The metal powder production apparatus of the present invention includes a storage unit for storing molten metal,
A flow path provided below the storage section, through which the molten metal flowing down from the storage section can pass, and a slit that opens to the lower end of the flow path and injects a fluid into the flow path. A nozzle comprising,
A supply unit provided above the storage unit and configured to supply molten metal to the storage unit;
It has at least a liquid surface portion of the stored molten metal, and has heating means for heating the molten metal.
Thereby, the metal powder manufacturing apparatus which can manufacture a high quality metal powder stably irrespective of a composition of the metal powder to manufacture is obtained.

In the metal powder manufacturing apparatus of the present invention, the supply unit is provided so as to extend downward from a lower surface of the supply unit container and a supply unit container for storing the molten metal, and the molten product stored in the supply unit container A supply tubular member through which the metal can pass,
It is preferable that the lower end of the supply portion cylindrical member is configured to be positioned below the liquid level of the molten metal stored in the storage portion.
Thereby, the molten metal supplied from a supply part will be transferred to a storage part, hardly touching external air. As a result, the temperature drop of the molten metal accompanying the transfer can be minimized, and the temperature control of the molten metal can be made easier.

In the metal powder manufacturing apparatus of the present invention, the storage section has a bottomed cylindrical shape, is provided so as to extend downward from a storage section container that stores molten metal, and a lower surface of the storage section container, and the storage section A reservoir cylindrical member that allows the molten metal stored in the container to pass through, and
It is preferable that the heating unit includes an induction heating coil disposed in a wall portion of the storage container and a power source that applies a voltage to the induction heating coil.
Thereby, since the temperature of a molten metal can be finely controlled, the temperature of the molten metal which fluctuates greatly in a short time can be reliably maintained constant.

In the metal powder manufacturing apparatus of the present invention, it is preferable that the heating means is configured to gradually increase the heating temperature in accordance with an elapsed time from when the molten metal starts to be stored in the storage unit.
Thereby, the control which maintains the temperature of a molten metal constant immediately after starting the storage of a molten metal can be performed easily.

In the metal powder manufacturing apparatus of the present invention, a temperature measurement unit that measures the temperature of the molten metal stored in the storage unit, and
It is preferable to have a control unit that controls the heating temperature by the heating unit based on the measured temperature of the molten metal.
Thereby, a metal powder production apparatus capable of producing a high-quality metal powder stably and easily regardless of the composition of the metal powder to be produced is obtained.

In the metal powder manufacturing apparatus of the present invention, a liquid level measuring unit that measures the height of the liquid level of the molten metal,
It is preferable to have a control unit that controls the amount of molten metal supplied by the supply unit based on the measured height of the liquid level.
Thereby, a metal powder production apparatus capable of producing a high-quality metal powder stably and easily regardless of the composition of the metal powder to be produced is obtained.

In the metal powder production apparatus of the present invention, the heating temperature by the heating means is preferably Tm + 50 [° C.] or higher, where the melting point of the composition of the molten metal is Tm [° C.].
As a result, the fluidity of the molten metal becomes uniform, and the molten metal becomes optimal in primary and secondary divisions. As a result, a fine metal powder having a uniform particle size can be reliably produced.

The metal powder manufacturing method of the present invention includes a storage part for storing molten metal,
A flow path that is provided below the storage section and through which the molten metal flowing down from the storage section can pass, and a slit that opens at a lower end of the flow path and injects fluid into the flow path; A nozzle comprising:
Using a metal powder manufacturing apparatus having a supply unit provided above the storage unit and configured to supply molten metal to the storage unit,
The molten metal is made to flow down from the storage part so as to pass through the flow path, and collides with the fluid, whereby the molten metal is refined and solidified to produce a metal powder,
The liquid level part of the molten metal stored in the storage part is heated.
Thereby, regardless of the composition of the metal powder to be manufactured, a high-quality metal powder can be stably manufactured.

It is a longitudinal cross-sectional view which shows typically 1st Embodiment of the metal powder manufacturing apparatus of this invention. FIG. 2 is a partial detail view of FIG. 1. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the metal powder manufacturing apparatus of this invention typically.

Hereinafter, a metal powder production apparatus and a metal powder production method of the present invention will be described in detail with reference to the accompanying drawings.
<Metal powder production equipment>
<< First Embodiment >>
First, a first embodiment of the metal powder production apparatus of the present invention will be described.
FIG. 1 is a longitudinal sectional view schematically showing a first embodiment of the metal powder production apparatus of the present invention, and FIG. 2 is a partial detailed view of FIG.

  A metal powder manufacturing apparatus 1 shown in FIG. 1 is an apparatus used for obtaining a metal powder by pulverizing a molten metal 90 by an atomizing method and solidifying it. The metal powder manufacturing apparatus 1 includes a supply unit 6, a storage unit (tundish) 2 provided below the supply unit 6, and a nozzle 3 provided below the storage unit 2. The reservoir 2 is provided with a heating means 8 for heating the molten metal 90.

Hereinafter, the configuration of each unit will be described.
(Supply section)
The supply unit 6 illustrated in FIG. 1 includes a supply unit container 61 having a bottomed cylindrical shape, and a supply unit cylindrical member 62 connected to the lower surface of the supply unit container 61. Among these, in the supply part container 61, the molten metal 90 which melt | dissolved the raw material of the metal powder to manufacture is temporarily stored. In addition, an opening 611 penetrating the bottom is provided in the center of the bottom of the supply container 61. The supply part cylindrical member 62 described above is connected to the lower surface of the supply part container 61 so that the hollow part and the opening 611 overlap each other. Accordingly, the molten metal 90 stored in the supply unit container 61 flows downward through the opening 611 and the supply unit cylindrical member 62, and subsequently stored in the storage unit 2.

Further, the supply container 61 may have a lid (not shown). By covering the lid, it becomes difficult for the stored molten metal 90 to come into contact with the atmosphere, so that oxidation of the molten metal 90, temperature reduction, and the like can be suppressed.
Furthermore, the inside of supply part container 61 can also be pressurized by putting a cover. In this case, since the molten metal 90 is discharged at a speed higher than the flow-down speed due to its own weight, the supply amount of the molten metal 90 per unit time can be controlled by appropriately adjusting the applied pressure.

  The constituent material of the supply section container 61 and the supply section cylindrical member 62 may be any material as long as it does not deform, melt, etc. by contact with the molten metal 90, for example, an iron-based material such as heat-resistant steel. Examples include various metal materials such as materials, tungsten-based materials, molybdenum-based materials, various ceramic materials such as alumina and zirconia, various carbon materials such as graphite, and alumina / graphite materials that are composite materials thereof. Used.

(Reservoir)
The storage part (tundish) 2 shown in FIG. 1 has a storage part container 21 having a bottomed cylindrical shape, and a storage part cylindrical member 22 connected to the lower surface of the storage part container 21. Among these, the storage part container 21 receives the molten metal 90 supplied from the supply part 6, and stores this temporarily. In addition, an opening 211 penetrating the bottom is provided in the center of the bottom of the storage container 21. The reservoir cylindrical member 22 described above is connected to the lower surface of the reservoir container 21 so that the hollow portion and the opening 211 overlap.
Therefore, the molten metal 90 stored in the storage container 21 flows downward through the opening 211 and the storage tubular member 22.
The constituent materials of the reservoir container 21 and the reservoir cylindrical member 22 are the same as the constituent materials of the supply container 61 and the supply cylindrical member 62.

(nozzle)
The nozzle 3 shown in FIG. 1 is provided with a nozzle body 30, a flow path 31 through which the molten metal 90 flowing down from the reservoir 2 passes, and a slit that ejects fluid into the flow path 31. 32 and a cover 7 provided on the lower surface of the nozzle body 30. For example, water is used as the fluid.

The nozzle body 30 shown in FIG. 1 has, for example, a cylindrical shape, and is arranged so that the axis thereof and the flow path of the molten metal 90 flowing down from the storage portion 2 coincide.
The nozzle body 30 is provided with a flow path 31 formed so as to penetrate along the axis and a slit 32 formed so as to open near the lower end of the flow path 31.
The flow path 31 is a through-hole penetrating the nozzle body 30 in the vertical direction, and the inner diameter of the through-hole changes continuously. Specifically, the flow path 31 is configured such that its inner diameter is the largest at the upper end of the flow path 31 and continuously decreases downward therefrom. As a result, the inner wall surface of the flow path 31 in this region is a smooth curved surface. In the vicinity of the middle of the flow path 31, the internal diameter of the flow path 31 is the smallest, and continuously increases again downward from there.

An introduction path 321 disposed in the nozzle body 30 is connected to the slit 32 formed in the nozzle body 30. The introduction path 321 connects a fluid supply source (not shown) provided outside the nozzle 3 and the slit 32, and the fluid supplied from the supply source passes through the introduction path 321 and the slit 32. And jetted toward the flow path 31.
In addition, the introduction path 321 has a wedge-shaped partial longitudinal cross-sectional shape. With such a shape, the fluid introduced into the introduction path 321 can gradually increase the flow velocity in the wedge-shaped portion. For this reason, by disposing the wedge-shaped portion immediately before the slit 32, a high-speed fluid can be stably ejected from the slit 32. Further, since the fluid is supplied to the introduction path 321 in a pressurized state, the nozzle body 30 is required to have sufficient pressure resistance.

The slit 32 is open over the entire circumference of the inner wall surface of the flow path 31. For this reason, the fluid ejected from the slit 32 having such a shape forms a conical fluid jet 33 as shown in FIG.
Such a constituent material of the nozzle body 30 may be the same as the constituent material of the supply section container 61 and the supply section cylindrical member 62, but a metal material is preferable. Thereby, the nozzle body 30 that achieves both heat resistance and pressure resistance applied to the fluid is obtained.

The cover 7 has a cylindrical shape, and is provided so that the axis thereof coincides with the axis of the flow path 31. By providing the cover 7 below the nozzle body 30, the falling metal powder can be prevented from being scattered, and the metal powder can be efficiently collected.
The cover 7 is preferably connected to the lower surface of the nozzle body 30 in an airtight manner. Thereby, it is possible to prevent outside air from flowing into the cover 7. As a result, when the molten metal 90 is pulverized and solidified to produce a metal powder, the molten metal 90 can be prevented from coming into contact with the outside air and the metal powder being oxidized and altered.

(Metal powder manufacturing method)
Next, the method (metal powder manufacturing method of this invention) which manufactures metal powder using the metal powder manufacturing apparatus 1 is demonstrated.
First, the molten metal 90 is stored in the supply unit container 61. The stored molten metal 90 flows down into the storage container 21 below through the supply cylindrical member 62.

The molten metal 90 that has flowed into the storage container 21 is stored in the storage container 21 and flows down toward the nozzle 3 below through the storage tubular member 22.
At this time, high-speed fluid is ejected from the slit 32 of the nozzle 3 to form a fluid jet 33. When the fluid jet 33 is formed, an air flow G from the upper side to the lower side of the flow path 31 is generated accordingly. This air flow G reduces the pressure in the flow path 31.
When the molten metal 90 that has flowed down from the storage tubular member 22 reaches the flow channel 31 in this state, the molten metal 90 is split (primary split) due to the pressure drop in the flow channel 31. This is caused by the fact that the surrounding decompression force exceeds the force with which the molten metal 90 tries to close. Due to this primary division, the molten metal 90 becomes a large number of droplets 91.

  At this time, it is preferable that the reservoir cylindrical member 22 is disposed so that the lower end of the reservoir cylindrical member 22 is located at a position where the inner diameter of the flow path 31 is minimized. When arranged in this manner, the pressure in the vicinity of the lower end of the reservoir cylindrical member 22 becomes the lowest, so that the molten metal 90 can be particularly finely divided in the primary division. As a result, in particular, a particularly fine metal powder can be produced.

  The droplet 91 generated by the primary division subsequently collides with the fluid jet 33. Due to the impact accompanying the collision with the fluid jet 33, the droplet 91 is further finely divided (secondary division). At the same time, the secondary split droplet 91 is rapidly cooled by the large heat capacity of the fluid jet 33. As a result, the temperature of the droplet 91 is below the melting point and solidifies. A metal powder is obtained as described above.

(Heating means)
Moreover, in this embodiment, since the storage part 2 is provided between the supply part 6 and the nozzle 3, the supply amount of the molten metal 90 to the nozzle 3 can be stabilized. That is, compared with the case where the molten metal 90 is directly supplied from the supply unit 6 to the nozzle 3, the molten metal 90 is temporarily supplied to the storage unit 2 and then flows down from the storage unit 2. It is easy to control the supply amount per unit time. For this reason, the manufacturing conditions of the metal powder are also constant, and a high-quality metal powder with a uniform particle size can be manufactured.

  Moreover, in this embodiment, since it was set as the structure which has the supply part 6 and the storage part 2 provided in the downward direction, even if the volume of the supply part container 61 is enlarged, it is hard to influence the quality of metal powder. There is an advantage. For this reason, the temperature drop of the molten metal 90 in the supply part container 61 can be suppressed by making the volume of the supply part container 61 sufficiently larger than the volume of the storage part container 21 (for example, 10 times or more). As a result, the quality of the finally obtained metal powder can be further improved.

By the way, in the metal powder manufacturing apparatus 1, as described above, the molten metal 90 is temporarily stored in the storage unit 2, and here a buffer function for making the supply amount per unit time constant is exhibited. For this reason, in order to ensure this buffer function, it is necessary to store a certain amount of molten metal 90 in the storage part 2.
However, in the conventional metal powder manufacturing apparatus, once the molten metal is stored, the supply amount of the molten metal supplied to the nozzle per unit time is constant, but the particle size of the finally obtained metal powder is inadequate. There was a problem of being uniform. For this reason, the particle size distribution of the metal powder becomes wide, and the characteristics of various metal products manufactured using the metal powder cannot be sufficiently improved. In particular, when an easily oxidizable element such as aluminum or titanium is included, the tendency is remarkable.

The present inventor has made extensive studies on this problem and found that the storage condition of the molten metal 90 in the storage unit 2 has a great influence on the particle size distribution of the finally obtained metal powder. And it discovered that the said subject was solved reliably by providing the heating means 8 for heating the molten metal 90 in the storage part 2, and came to complete this invention.
Examples of the heating means 8 include those using various heating principles such as induction heating, resistance heating, microwave heating and the like, and are not particularly limited. Here, a case where induction heating is used will be described. . Since the heating by induction heating can directly generate heat from the molten metal 90, the heating efficiency is high, and the temperature of the molten metal 90 can be finely controlled. It is effective in maintaining a constant value.

The metal powder manufacturing apparatus 1 includes a heating unit 8 including an induction heating coil 81 built in a wall portion of the storage container 21 and a control unit 82 electrically connected to the induction heating coil 81. Yes. By applying a voltage to the induction heating coil 81 from the control unit 82, the reservoir container 21 and the molten metal 90 are heated, and the condition of the molten metal 90 stored in the reservoir 2 is maintained at a condition suitable for the atomization method. can do. As a result, when the molten metal 90 undergoes primary splitting and secondary splitting, variation in conditions over time can be suppressed, so that it can be split under uniform conditions and a metal powder having a uniform particle size can be produced. it can.
Moreover, according to such a metal powder manufacturing apparatus 1, it is possible to manufacture a high-quality metal powder having a narrow particle size distribution even for the molten metal 90 containing an element that is easily oxidized and easily generates a metal oxide.

  About the reason by which the said subject is solved by providing the heating means 8, since a several factor is concerned, it cannot specify unconditionally, but one is by suppressing the temperature fall of the molten metal 90. It is conceivable that a decrease in fluidity (increase in viscosity) of the molten metal 90 is suppressed and variation in easiness of division in primary and secondary divisions is suppressed. From this point of view, it is considered that the temperature of the molten metal 90 is preferably maintained constant when the molten metal 90 is heated.

Here, the configuration of each part of the heating means 8 will be described in detail.
The induction heating coil 81 shown in FIGS. 1 and 2 is built in the wall portion of the reservoir container 21. By being provided in the wall portion, it is possible to prevent the induction heating coil 81 and the molten metal 90 from contacting each other, prevent contamination of the molten metal 90, and prevent the induction heating coil 81 from deteriorating.

The constituent material of the induction heating coil 81 is not particularly limited as long as it is a conductive material, and examples thereof include copper, aluminum, and brass. The induction heating coil 81 is generally formed by forming a tubular body made of the above-described material into a coil shape, and cooling water is passed through the tubular body.
A control unit 82 is electrically connected to the induction heating coil 81. The control unit 82 includes a power source that applies a voltage to the induction heating coil 81 and a control circuit that controls the operation of the power source. As the power source, a high frequency power source is generally used, and an AC voltage having a frequency of about 1 kHz to 500 kHz is applied to the induction heating coil 81.

  The control circuit controls the operation of the power source based on a preset program or input information. Thereby, the temperature of the molten metal 90 is controlled within a predetermined range. As a specific example of the program, there is a program that gradually increases the heating temperature by the induction heating coil 81 according to the elapsed time from when the molten metal 90 starts to be stored in the storage container 21. By setting such a program, it is possible to easily perform control for maintaining the temperature of the molten metal 90 constant immediately after the storage of the molten metal 90 is started.

The heating temperature by the heating means 8 (temperature of the molten metal 90 at the heating center) is appropriately set according to the amount, composition, etc. of the molten metal 90. Specifically, when the melting point of the composition of the molten metal 90 is Tm [° C.], the heating temperature is preferably Tm + 50 [° C.] or higher, more preferably Tm + 100 [° C.] or higher and Tm + 300 [° C.] or lower. Preferably, it is Tm + 150 [° C.] or higher and Tm + 250 [° C.] or lower. By setting the heating temperature of the molten metal 90 within the above range, the fluidity of the molten metal 90 becomes uniform, and the molten metal 90 becomes optimal in primary splitting and secondary splitting. For this reason, by setting the heating temperature of the molten metal 90 within the above range, a fine metal powder having a uniform particle diameter can be reliably produced.
Further, when maintaining the temperature of the molten metal 90 constant, it is preferable to control the temperature range during the maintenance to be 30 ° C. or less, and it is more preferable to control to be 20 ° C. or less. .

  Although it is possible to measure the temperature of the molten metal 90 stored, it is possible to measure the temperature via the partition wall because of the harsh environment of measuring the temperature of the hot molten metal 90 or an infrared sensor. It is necessary to measure using For this reason, the temperature cannot be measured continuously in real time, or the temperature below the liquid level cannot be measured. From this point as well, the heating operation by the heating means 8 is based on a preset program. It is useful to do. In particular, in the storage unit 2 of the metal powder manufacturing apparatus 1 shown in FIG. 1, the molten metal 90 is caused to flow downward, while new molten metal 90 is supplied from above, so that the temperature of the molten metal 90 increases in a short time. Will fluctuate. For this reason, the program setting as described above is effective.

  Further, the installation position of the induction heating coil 81 may be the entire wall portion of the reservoir container 21, or may be only the liquid surface portion of the molten metal 90 in the wall portion. In the former case, the entire molten metal 90 being stored can be heated uniformly, and in the latter case, only the liquid surface part that is likely to be lowered in temperature is heated, thereby efficiently preventing the temperature of the molten metal 90 from being lowered. Useful. Moreover, since the molten metal 90 is supplied to the reservoir container 21 shown in FIG. 1 from the supply unit 6 located above the reservoir container 21, the molten metal 90 is stored in the lower part in the central portion of the reservoir container 21. The flow toward A part of the flow of the molten metal 90 hits the bottom of the storage container 21 and goes toward the wall. In the latter case, since only the liquid surface portion of the molten metal 90 is heated, the molten metal 90 moving downward is also slightly higher in temperature than the surroundings. For this reason, after heading for the wall part side, the flow which goes upwards again along a wall part is produced. As a result, in the latter case, convection is generated in the molten metal 90 being stored, and the effect that the temperature of the entire molten metal 90 tends to be uniform is also obtained.

  The liquid surface portion of the molten metal 90 is defined as follows. Although slightly different depending on the shape of the reservoir container 21, when the depth from the liquid surface of the molten metal 90 to the bottom surface of the reservoir container 21 is D1, a region having a depth of 0.4D1 or less from the liquid surface of the molten metal 90 Is the liquid surface. Therefore, the effect of the present invention described above can be enjoyed by providing the heating means 8 in this depth region.

Further, when the distance from the liquid level of the molten metal 90 to the lower end of the heating means 8 is D2, D2 is preferably 0.3D1 or less, and more preferably 0.2D1 or less. By setting the arrangement of the heating means 8 so as to satisfy the above-described conditions, the effects as described above are more remarkably exhibited. As a result, a high-quality metal powder having a uniform particle size can be produced more reliably.
The position of the upper end of the heating means 8 is not particularly limited, but is preferably above the liquid level of the molten metal 90. Thereby, the liquid level part of the molten metal 90 can be heated more reliably.

Further, the lower end of the supply portion cylindrical member 62 may be located above the liquid level of the molten metal 90 stored in the storage portion container 21, but is preferably located below the liquid level. preferable. By setting the position of the supply portion cylindrical member 62 in this way, the molten metal 90 supplied from the supply portion 6 is transferred to the storage portion container 21 with little contact with the outside air. As a result, the temperature drop of the molten metal 90 accompanying the transfer can be minimized, and the temperature control of the molten metal 90 can be made easier.
In this case, when the distance from the liquid level of the molten metal 90 to the lower end of the supply portion cylindrical member 62 is D3, D3 is preferably 0.01D2 or more and 0.8D2 or less, and 0.05D2 or more and 0.0. More preferably, it is 6D2 or less. By setting D3 within the above range, the temperature of the molten metal 90 can be kept more uniform and constant.

  In addition, when manufacturing metal powder, the liquid level of the molten metal 90 stored in the storage container 21 is appropriately adjusted by appropriately adjusting the supply amount of the molten metal 90 supplied from the supply unit 6 to the storage unit 2. It is preferable to control so that the height is constant. Thereby, the temperature of the molten metal 90 can be controlled more strictly. In order to adjust the supply amount of the molten metal 90, for example, an opening / closing valve or the like may be provided in the middle of the supply portion cylindrical member 62, and this may be opened / closed. At this time, the vertical width of the height of the liquid surface is preferably 50 mm or less, and more preferably 30 mm or less.

The heating unit 8 has been described above, but the configuration of the heating unit 8 is not limited to the above. For example, the induction heating coil 81 may not be incorporated in the wall portion of the reservoir container 21 and may be provided outside the wall portion.
Further, the supply unit 6 may be replaced with another one (for example, a melting furnace or the like) as long as it can supply the molten metal 90 to the storage unit 2.
In addition, the output adjustment of the induction heating coil in the heating means 8 may be configured to be artificially adjusted, not only when it is made based on a program input in advance.

<< Second Embodiment >>
Next, a second embodiment of the metal powder production apparatus of the present invention will be described.
FIG. 3 is a longitudinal sectional view schematically showing a second embodiment of the metal powder production apparatus of the present invention.
Hereinafter, although the second embodiment will be described, the description will focus on the differences from the first embodiment, and the description of the same matters will be omitted.
The second embodiment is the same as the first embodiment except that the configuration of the heating means is different.

  In the present embodiment, the heating unit 8 includes a first temperature sensor (temperature measurement unit) 83 that measures the temperature of the molten metal 90 stored in the storage unit container 21 in addition to the induction heating coil 81 and the control unit 82. A liquid level monitor 84 that detects the height of the liquid level of the molten metal 90 stored in the storage container 21, and a second temperature sensor that measures the temperature of the molten metal 90 stored in the supply container 61. (Temperature measuring unit) 85 and an opening / closing valve 86 for adjusting the amount of molten metal 90 passing through the supply unit cylindrical member 62 per unit time. The first temperature sensor 83, the liquid level monitor (liquid level measuring unit) 84, and the second temperature sensor 85 are electrically connected to the control unit 82, and send the measurement result and the detection result to the control unit 82. It is configured as follows. In addition, the on-off valve 86 is also electrically connected to the control unit 82, and is configured such that its opening / closing operation is controlled by the control unit 82. The control unit 82 adjusts the output applied to the induction heating coil 81 and the opening / closing amount of the on-off valve 86 based on the measurement result and the detection result, thereby adjusting the temperature of the molten metal 90, the height of the liquid level, and the like. Control to keep the conditions constant can be performed more easily and reliably. In some cases, more strict control is possible by previously inputting conditions such as the composition of the molten metal 90, the temperature, and the capacities of the storage container 21 and the supply container 61 to the controller 82. As described above, according to the present embodiment, the state of the molten metal 90 is centrally managed by the control unit 82, and the heating amount and the like are automatically controlled based on the state. Therefore, regardless of the composition of the molten metal 90, High quality metal powder can be reliably produced. That is, the control unit 82 according to the present embodiment is configured to perform feedback control.

In this case, since the measured values by the first temperature sensor 83 and the second temperature sensor 85 have a time lag with respect to the actual temperature change, the time lag is corrected based on the experience values inputted in advance. It is preferable to do this.
Moreover, in this embodiment, the induction heating coil 81 is divided into a plurality of parts, and is configured so that a voltage can be applied independently to each part. Thereby, a different voltage can be applied for every part, and, thereby, the amount of heating of the molten metal 90 can be made different for each depth from the liquid surface. As a result, the temperature of the molten metal 90 can be maintained more uniformly.

  As mentioned above, although the metal powder manufacturing apparatus and metal powder manufacturing method of this invention were demonstrated based on embodiment of illustration, this invention is not limited to these, For example, each part which comprises a metal powder manufacturing apparatus is It can be replaced with any structure capable of performing the same function. Moreover, arbitrary components may be added.

1. Production of metal powder (Example 1)
First, stainless steel SUS316L (melting point Tm: 1450 ° C.) was melted in a high frequency induction furnace to obtain a molten metal.
Next, the obtained molten metal was transferred into a supply container of the metal powder production apparatus shown in FIG. And while making molten metal flow down to a storage part and a nozzle, the molten metal was pulverized by injecting a water jet from the slit of a nozzle. Thereby, metal powder was obtained.

In addition, the structure of each part of a metal powder manufacturing apparatus is as follows.
・ Material of supply container: Alumina / graphite composite material ・ Material of storage container: alumina / graphite composite material ・ Inner diameter of supply tubular member: 5 mm
・ Inner diameter of reservoir cylindrical member: 5 mm
-Depth D1 from the liquid surface to the bottom surface of the molten metal in the reservoir container: 300 mm
-Distance D2 from the liquid level of the molten metal in the reservoir container to the lower end of the heating means: 50 mm
-Distance D3 from the liquid level of the molten metal to the lower end of the supply tubular member: 40 mm
Moreover, the temperature of the molten metal in a metal powder manufacturing apparatus is as follows.
-Initial temperature of molten metal stored in the supply section container: 1720 ° C
-Heating temperature of molten metal stored in storage container: 1650 ° C

Further, during the production of the metal powder, the supply amount of the molten metal supplied from the supply unit is appropriately adjusted so that the liquid level of the molten metal in the storage container is constant. It was confirmed that the vertical height of the liquid level at the time of this adjustment was within 30 mm.
In addition, in the heating means, since it was measured in advance that the temperature of the molten metal stored in the storage container was decreased by 1.5 ° C. per minute, based on this decrease rate, the temperature decrease should be canceled out. A program was input in advance so as to gradually increase the heating temperature according to the elapsed time after the start of storage of the molten metal. As a result, the temperature of the molten metal could be kept substantially constant at the above temperature from the start to the end of the production of the metal powder (temperature range: about 10 ° C.).

(Example 2)
A metal powder was obtained in the same manner as in Example 1 except that the heating temperature of the molten metal stored in the storage container was changed to 1575 ° C.
(Example 3)
A metal powder was obtained in the same manner as in Example 1 except that the heating temperature of the molten metal stored in the storage container was changed to 1720 ° C.

(Example 4)
A metal powder was obtained in the same manner as in Example 1 except that D2 was changed to 90 mm and the heating temperature of the molten metal was changed to the temperature shown in Table 1.
(Example 5)
A metal powder was obtained in the same manner as in Example 1 except that D2 was changed to 120 mm.

(Example 6)
Example 1 with the exception of using the apparatus in which the induction heating coil was changed to lay the entire reservoir container in the metal powder production apparatus shown in FIG. 1 and changing the heating temperature of the molten metal to the temperature shown in Table 1. A metal powder was obtained in the same manner.
(Example 7)
A metal powder was obtained in the same manner as in Example 1 except that D3 was changed to 30 mm and the heating temperature of the molten metal was changed to the temperature shown in Table 1.

(Example 8)
A metal powder was obtained in the same manner as in Example 1 except that D3 was changed to 0 mm and the heating temperature of the molten metal was changed to the temperature shown in Table 1.
Example 9
A metal powder was obtained in the same manner as in Example 1, except that the metal powder production apparatus shown in FIG. 3 was used and the heating temperature of the molten metal was changed to the temperature shown in Table 1.

Here, the heating means was controlled as follows. The first temperature sensor and the second temperature sensor were each attached near the bottom of the container.
First, the liquid level of the molten metal stored in the storage container is detected by the liquid level monitor, and the opening / closing amount of the on-off valve attached to the supply tubular member so that this height is constant Controlled. Thereby, the height of the liquid level could be maintained constant.

  Moreover, the output applied to the induction heating coil was controlled based on the measured value by the first temperature sensor, the measured value by the second temperature sensor, and the heating temperature. Specifically, the difference between the measured value by the first temperature sensor and the heating temperature was determined, and the output applied to the induction heating coil was controlled so that this was close to zero. In the calculation for obtaining the output, the measurement value by the second temperature sensor is used, and when this measurement value exceeds the heating temperature, the amount of heat is converted into the output, the output is reduced, When the temperature was lower than the heating temperature, the amount of heat was converted into an output, and control was performed to correct the calculation result so as to increase the output.

(Example 10)
A metal powder was obtained in the same manner as in Example 1 except that aluminum (melting point Tm: 660 ° C.) was used instead of stainless steel.
In addition, the temperature of the molten metal in a metal powder manufacturing apparatus is as follows.
-Initial temperature of molten metal stored in the supply container: 950 ° C
-Heating temperature of molten metal stored in storage container: 900 ° C

  In addition, in the heating means, it was measured in advance that the temperature of the molten metal stored in the storage container decreased by 2 ° C. per minute. Therefore, based on this decrease rate, the melting was performed so as to counteract this temperature decrease. A program was input in advance so as to gradually increase the heating temperature in accordance with the elapsed time after the start of metal storage. As a result, the temperature of the molten metal could be kept substantially constant at the above temperature from the start to the end of the production of the metal powder (temperature range: about 10 ° C.).

(Example 11)
A metal powder was obtained in the same manner as in Example 10 except that the heating temperature of the molten metal stored in the storage container was changed to 800 ° C.
(Example 12)
A metal powder was obtained in the same manner as in Example 10 except that the heating temperature of the molten metal stored in the storage container was changed to 950 ° C.

(Comparative Example 1)
A metal powder was obtained in the same manner as in Example 1 except that the installation of the heating means was omitted.
(Comparative Example 2)
A metal powder was obtained in the same manner as in Comparative Example 1 except that aluminum (melting point Tm: 660 ° C.) was used instead of stainless steel.
In addition, the temperature of the molten metal in a metal powder manufacturing apparatus is as follows.
-Initial temperature of molten metal stored in the supply container: 950 ° C

2. Evaluation of metal powder About the metal powder obtained by each Example and each comparative example, the average particle diameter and the standard deviation were measured with the laser diffraction type particle size distribution measuring apparatus. The average particle diameter is the particle diameter (μm) when the cumulative amount is 50% on a volume basis. The standard deviation is defined by the following equation and serves as a guide for the width of the particle size distribution.
(Standard deviation) = (d84% −d16%) / 2

However, d84% is the particle size (μm) when the cumulative amount is 84% on the volume basis, and d16% is the particle size (μm) when the cumulative amount is 16% on the volume basis.
These results are shown in Table 1. In addition, about the standard deviation of the metal powder obtained in Examples 1-9, it shows by a relative value when the standard deviation of the metal powder obtained in Comparative Example 1 is set to 1, and is obtained in Examples 10-12. The standard deviation of the metal powder is shown as a relative value when the standard deviation of the metal powder obtained in Comparative Example 2 is 1.

As shown in Table 1, it was clarified that the metal powder obtained in each example was a powder having a small particle size and a uniform particle size as compared with the metal powder obtained in each comparative example. .
In particular, in the metal powders obtained in Examples 1, 7, 9, and 10, such a tendency was remarkable.

  DESCRIPTION OF SYMBOLS 1 ... Metal powder manufacturing apparatus 2 ... Storage part 21 ... Storage part container 211 ... Opening 22 ... Storage part cylindrical member 3 ... Nozzle 30 ... Nozzle main body 31 ... Flow path 32 ... Slit 321 ... ... Introduction path 33 ... Fluid jet 6 ... Supply part 61 ... Supply part container 611 ... Opening 62 ... Supply part cylindrical member 7 ... Cover 8 ... Heating means 81 ... Induction heating coil 82 ... Control Part 83 …… First temperature sensor 84 …… Liquid level monitor 85 …… Second temperature sensor 86 …… Open / close valve 90 …… Mold metal 91 …… Droplet G …… Air flow

Claims (8)

A reservoir for storing molten metal;
A flow path provided below the storage section, through which the molten metal flowing down from the storage section can pass, and a slit that opens to the lower end of the flow path and injects a fluid into the flow path. A nozzle comprising,
A supply unit provided above the storage unit and configured to supply molten metal to the storage unit;
The metal powder manufacturing apparatus characterized by having a heating means which is provided at least in the liquid surface part of the stored molten metal among the storage parts and heats the molten metal. The supply unit is provided so as to extend downward from a lower surface of the supply unit container and a supply unit container that stores the molten metal, and the supply of the molten metal stored in the supply unit container is allowed to pass therethrough A cylindrical member,
The metal powder manufacturing apparatus of Claim 1 comprised so that the lower end of the said supply part cylindrical member may be located below the liquid level of the molten metal stored in the said storage part. The storage part has a bottomed cylindrical shape, and is provided so as to extend downward from a storage part container for storing molten metal and a lower surface of the storage part container, and the molten metal stored in the storage part container A storage tubular member capable of passing,
The metal powder manufacturing apparatus according to claim 1, wherein the heating unit includes an induction heating coil disposed in a wall portion of the reservoir container, and a power source that applies a voltage to the induction heating coil. .   The metal powder according to any one of claims 1 to 3, wherein the heating means is configured to gradually increase the heating temperature in accordance with an elapsed time from when the molten metal starts to be stored in the storage portion. Manufacturing equipment. Furthermore, a temperature measurement unit that measures the temperature of the molten metal stored in the storage unit,
The metal powder manufacturing apparatus according to claim 1, further comprising: a control unit that controls a heating temperature by the heating unit based on the measured temperature of the molten metal. Furthermore, a liquid level measuring unit for measuring the height of the liquid level of the molten metal,
The metal powder manufacturing apparatus according to claim 1, further comprising: a control unit that controls a supply amount of the molten metal by the supply unit based on the measured height of the liquid level.   The apparatus for producing metal powder according to any one of claims 1 to 6, wherein the heating temperature by the heating means is Tm + 50 [° C] or higher, where Tm [° C] is the melting point of the composition of the molten metal. A reservoir for storing molten metal;
A flow path that is provided below the storage section and through which the molten metal flowing down from the storage section can pass, and a slit that opens at a lower end of the flow path and injects fluid into the flow path; A nozzle comprising:
Using a metal powder manufacturing apparatus having a supply unit provided above the storage unit and configured to supply molten metal to the storage unit,
The molten metal is made to flow down from the storage part so as to pass through the flow path, and collides with the fluid, whereby the molten metal is refined and solidified to produce a metal powder,
A method for producing a metal powder, comprising heating a liquid surface portion of the molten metal stored in the storage portion.

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