JPH03247709A - Apparatus for manufacturing metal powder - Google Patents

Abstract

PURPOSE:To stably manufacture metal fine powder by controlling ratio of interval between lower end of a molten metal flowing-down nozzle and an atomizing nozzle to the max. diameter of atomizing medium jet to the specific value at the time of finely pulverizing after rapidly cooling and solidifying molten metal while blowing atomizing medium to the molten metal stream from the nozzle. CONSTITUTION:The molten metal from a melting apparatus 1 composed of a melting furnace 1a and a tundish 1b is caused to flow down as the bar-like molten metal stream 7 from molten metal nozzle 6 arranged at bottom part in the tundish 1b and rapidly cooled and solidified by blowing the atomizing medium jet 9 of water, etc., from an injecting hole 2b in the atomizing nozzle 2 arranged at the circumference thereof against the molten metal stream 7 to make the atomizing medium slurry of fine metal powder and water, etc., and after charging this into a slurry storing vessel 5 through gas-liquid separating vessel 4, the metal fine particles are recovered. In this case, by arranging a cooling means 8 in inner part of the atomizing nozzle 2, the injecting hole 2b of the atomizing medium jet 9 approaches the molten metal nozzle 6 without deforming the atomizing nozzle 2 at high temp., and by forming the interval (l) between the lower end of molten metal nozzle 6 and the injecting hole 2b for atomizing medium jet to <= two times the max. diameter (d) of the atomizing medium jet 9, the metal fine powder is stably manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a metal powder manufacturing apparatus using a spraying method, which is used for manufacturing metal powder for powder metallurgy.

<Prior Art> A metal powder manufacturing apparatus using a liquid spraying method, which is one of the general metal powder manufacturing methods, includes a molten metal supply device 1 such as a melting furnace or a tundish, as shown in FIG. It is generally comprised of a pressure booster 13 that boosts the pressure of the spray medium, a spray nozzle 2 that jets out the spray medium, a device 5 that collects the slurry after spraying, and others.

Spray nozzles are the most important component of metal powder manufacturing equipment and have been studied for a long time. An example of a conventional general spray nozzle is shown in FIG. 5 disclosed in Japanese Patent Application Laid-Open No. 43-6389.

9 is a spray medium jet.

Incidentally, with the recent development of powder metallurgy technology, the need for fine metal powder has increased.

This has a particle size of 10 μm, which has excellent sinterability for injection molding, etc.
This is because a fairly fine powder is required.

Various methods for producing fine powder have been proposed and implemented;
The atomization method, which has traditionally been applied to the production of metal powders for powder metallurgy, is said to be suitable for producing alloy powders on the order of micrometers in size, in which metal powder is obtained by atomizing and cooling a molten metal stream with a high-pressure atomizing medium. .

In the general conventional spraying method, the average particle size used for compression molding is 6.
Although only powder of about 0 LLm was obtained, the pressure of the spray medium was reduced to 50
The particle size is 10LL using technology that makes it more than 0 kg/cm2.
It has become possible to produce a fine powder of about 1.0 m in size, and it is manufactured industrially. As an example of a spray nozzle for this high-pressure spray,
The spray nozzle described in No. 2152605 is shown in FIG.

6 is a molten metal nozzle, and 7 is a molten metal flow.

<Problems to be Solved by the Invention> The nozzle 2 for producing fine metal powder shown in FIGS. Although a powder as fine as OLLm can be obtained, the stability of the spray is insufficient for production on an industrial scale in the following points.

That is, (1) the distance of the spray medium jet 9 from the molten metal nozzle 6 provided in the molten metal supply device is increased, and the molten metal flow 7 from the spray nozzle 2 is increased;
Blockage accidents are likely to occur due to contact with

(2) In order to avoid the problem (2), if the molten metal nozzle 6 is placed close to the spray nozzle 2, the spray nozzle 2 will be affected by heat and the spray pressure will drop.

■ Conventional equipment cannot perform vacuum pouring, which is effective for pouring molten metal into a small diameter, so there is a limit to how small the diameter of the molten metal nozzle 6 can be made.

■ Spraying becomes unstable due to pressure fluctuations in the spray tank 11.

There are four types of problems: The details of these problems will be explained below.

That is, as shown in FIG. 5, in the conventional spray nozzle for manufacturing powder for compression molding, the distance t between the spray nozzle upper surface 2a and the spray medium jet outlet 2b is small, and the distance t from the molten metal nozzle provided in the molten metal supply device is small. The flowing molten metal stream was stably sprayed by the spray medium jet 9 directly below. However, the spray nozzle 2 for producing fine powder, such as the spray nozzle 2 shown in the above-mentioned Japanese Patent Application Laid-Open No. 62-152605 and the spray nozzle 2 shown in FIG. 7 invented by the present inventors, is generally capable of high-pressure spraying compared to the spray nozzle 2 shown in FIG. 5. Therefore, the distance t between the spray nozzle top surface 2a and the spray medium jet 1-spout port 2b is large (in other words, the spray nozzle 2 is thick), and the molten metal pouring port 6a is generally small (the molten metal nozzle is thick). Due to the misalignment of the position of the molten metal 6, an increase in the airflow velocity at the pouring port 68, turbulence of the airflow, etc., the molten metal flow 7 comes into contact with the side wall portion of the atomizing medium jet outlet 2b, lowering the atomizing medium pressure, and disturbing the atomizing medium jet 9. In the worst case, the molten metal solidified at the spray medium jet outlet 2b, blocking the spray outlet 2b and making spraying impossible.

As a solution to this problem, a method can be considered in which a molten metal nozzle is combined with a spray nozzle and the molten metal nozzle is brought close to the spray medium jet.

For example, as described in the embodiment of Japanese Patent Publication No. 52-49784 shown in FIG. 8, the above problem can be solved if both devices can be placed close to each other. 3 is a spray chamber, and 10 is a non-oxidizing gas supply pipe.

However, when this method was applied to the production of fine powder, the following problems occurred. In other words, a spray medium pressure of 500 kgf/cm" or more is required to produce powder with a particle size of about 0.4 cm", and in order to maintain this pressure and obtain a stable spray medium jet, the rigidity of the spray nozzle 2 is required. Although it is necessary to prevent nozzle deformation as much as possible by ensuring that the molten metal nozzle 6 is sufficiently The temperature of the spray nozzle 2 increases due to heat radiation during supply, causing thermal deformation of the spray nozzle 2, resulting in a problem that proper spray pressure cannot be maintained.

Furthermore, it is effective to reduce the diameter of the molten metal nozzle 60 to improve the yield of fine powder, and the present inventors have proposed a method for stable pouring of molten metal using a small diameter molten metal nozzle in Japanese Patent Application No. 1-50539. However, in conventional equipment, the lower end of the molten metal nozzle 6 required for pouring and spraying with this method was set at a distance of 8000 m from atmospheric pressure.
It was difficult to pour and spray molten metal with a diameter of 3.5 mm or less from the molten metal nozzle 6 because it was not possible to adjust the pressure range up to about mH20.
In order to carry out this reduced pressure pouring method, not only the pressure adjustment range but also the accuracy and responsiveness of the pressure adjustment are important, and such a pouring device has not been seen before.

In addition, when providing this pressure adjustment, if the distance between the molten metal nozzle and the spray medium jet is increased, the spray stability will be impaired. The pressure adjustment of the spray nozzle chamber 12 was not suitable as an apparatus for producing fine powder.

Furthermore, when we attempted to produce powder using the apparatus disclosed in Japanese Patent Publication No. 52-49784 at a spray medium pressure of 1000 kgf/cm2, the spray medium slurry accumulated in the spray tank 11 shown in Fig. The jet oscillated, which disturbed the air flow in the spray tank 11, causing a phenomenon in which the spray medium jet became unstable and inhibited stable spraying.

In the atomization method, the pressure and airflow velocity below the molten metal nozzle (the spray medium jet outlet and its upper part) have a large effect on the stability of the molten metal flow. It is important for ensuring sex. Conventionally, the atmosphere is often supplied to the atomizing medium jet outlet and the upper part thereof by a combination of a circulation piping 15 from the atomizing tank 11 and a gas supply 16, as shown in FIG.
Various other methods, such as the example shown in FIG. 9, have been proposed and implemented.

However, if these devices are directly applied to metal powder manufacturing equipment for fine powder production, the distance between the molten metal supply device such as a tundish and the spray nozzle will become further apart, the spray nozzle for fine powder production will be thick, and the injection port will be narrow ( , and the high airflow velocity makes stable injection increasingly difficult.

That is, metal powder manufacturing equipment using the conventional atomization method cannot stably produce powder with a particle size of about 10 jLm.

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal powder manufacturing apparatus that solves the above problems and enables stable production of fine powder.

Means for Solving the Problems> In order to achieve the above object, the present invention includes a molten metal supply device, a spray nozzle, a spray chamber, and a Slano storage tank, and the molten metal is poured from the molten metal nozzle of the molten metal supply device. A device for producing metal powder by atomizing, pulverizing, and cooling a molten metal flow in the spray chamber with a liquid spray medium jet sprayed from the spray nozzle, the apparatus comprising: a lower end of the molten metal nozzle and the spray The nozzle is arranged such that the distance β from the spray medium jet outlet is not more than twice the maximum diameter d of the spray medium jet, and at least a part of the surface portion of the spray nozzle facing the molten metal supply device. A metal powder manufacturing apparatus is provided, characterized in that it is equipped with a cooling means.

Further, according to the present invention, in the metal powder manufacturing apparatus, a pressure regulating gas supply means is provided in a space substantially cut off from the outside air and constituted by the molten metal supply device, the spray nozzle, and the spray medium jet. A metal powder manufacturing apparatus is provided.

Further, according to the present invention, there is provided a metal powder manufacturing apparatus characterized in that the metal powder manufacturing apparatus includes a gas-liquid separation tank between the spray chamber and the slurry storage tank.

The present invention will be explained in more detail below.

An example of the overall configuration of the present invention is shown in FIG. 1, and details of the spray nozzle section are shown in FIG. 2. In the figure, 1 is a molten metal supply device consisting of a melting furnace 1a or a tundish 1b, which melts metal according to the chemical composition of the required metal powder and flows the molten metal downward. Tundish 1b for large equipment
is generally used, but in small-scale spray equipment, direct melting furnace 1 is used.
The molten metal may be supplied from a.

The molten metal flows downward from a molten metal nozzle 6 at the bottom of the molten metal supply device 1 in the form of a rod-shaped molten metal stream 7. Reference numeral 2 designates a spray nozzle, and the spray medium whose pressure has been increased by the spray medium pressurization device 13 passes through a high-pressure pipe 14 and is ejected from this nozzle 2 as a spray medium jet 9. Although various shapes of the spray medium jet 9 have been proposed and implemented, most shapes cover the molten metal flow 7 from the periphery, and an inverted cone shape, V shape, etc. are common. The present invention may be applied to these spray nozzle types, and the maximum diameter d of the spray medium jets 1 to 9 (for V type, the spacing between the spray slits),
The structure is such that the relationship between the distance between the molten metal nozzle 6 and the spray medium jet outlet 2b can be appropriately selected. FIG. 2 shows an example of an inverted conical shape.

1 A spray chamber 3 extends from the bottom of the spray nozzle 2, a gas-liquid separation tank 4 is connected to the bottom end of the spray chamber, and a slurry storage tank 5 is provided at the bottom of the gas-liquid separation tank 4. .

The molten metal stream 7 injected with the high-speed flow of the atomizing medium jet 9 is atomized and pulverized in the atomizing chamber 3 .

The metal powder generated in the spray chamber 3 becomes a slurry of the spray medium and the body, and reaches the gas-liquid separation tank 4 at high speed while being accompanied by the atmosphere. The slurry is rotated in the gas-liquid separation tank 4 to separate gas, and then stored in the slurry storage tank 5.

In order to avoid instability of the spray, such as solidification and blockage of the spray medium jet outlet 2b due to disturbance of the molten metal flow 7, which was a problem in producing fine powder by the conventional spraying method, in the present invention, the molten metal nozzle 6
was combined with the spray nozzle 2, and the distance C between the lower end of the molten metal nozzle 6 and the spray medium jet outlet 2b was made close to twice (2d) or less the maximum diameter d of the spray medium jet 9.

2 By combining and bringing both nozzles 6.2 close to each other in this way, the positional deviation between the molten metal nozzle 6 and the spray nozzle can be minimized, and blockage accidents caused by the positional deviation of the molten metal nozzle 6 can be prevented.

In addition, in the conventional device, the molten metal flow 7 was disturbed by the airflow generated by the spray medium jet 9, making the spraying unstable. Since the molten metal flow 7 does not come into contact with the spray nozzle 2 even if turbulence occurs, stable spraying is possible.

FIG. 11 shows the maximum diameter d of the spray medium jet 9 and the molten metal nozzle 6.
The occurrence rate of the clogging phenomenon at the atomizing medium jet outlet 2b is shown when the distance C between the lower end and the atomizing medium jet outlet 2b is changed. In addition, ○ in the figure indicates that the spray medium jet diameter d is 16 m.
m is the result under the condition that the convergence angle of the spray medium is 30 degrees, and △ is the result when the spray medium jet diameter d is 10 mm and the convergence angle of the spray medium is 40 degrees.
This is the result of degree. However, the convergence angle is
The apex angle of Further, the apparatus shown in FIG. 2 was used, pure iron and nickel were used as the metals, water was used as the spray medium, and the test was carried out under the following conditions.

Melt? 8 Temperature 1650"C1 molten metal nozzle diameter 3mmφ, spray medium pressure 1000kgf/cm", water amount 130
It was carried out at ℃/min.

As is clear from FIG. 11, if the ratio ρ/d between the distance β between the lower end of the molten metal nozzle 6 and the spray medium jet outlet 2b and the maximum diameter d of the spray medium jet 9 is larger than 2, the molten metal flow 7 Even if a small turbulence occurs, 1 volume of hot water will flow through the spray medium jet outlet 2b.
The molten metal is likely to solidify and clog in this part due to contact with the spray medium, resulting in a high blockage rate.When this fl/d was set to 2 or less, no blockage occurred at any spray medium jet diameter d.Therefore, the present invention The claimed range is the distance 4 between the lower end of the molten metal nozzle and the spray medium jet outlet, or the maximum diameter d of the spray medium jet.
(2d) or less.

In the conventional technology, the proximity of the molten metal supply device 1 and the spray nozzle 2 causes the temperature of the spray nozzle 2 to rise due to heat radiation from the molten metal supply device 1, causing thermal deformation of the spray nozzle 2. In addition, in the case of fine powder production using a high pressure of the spray medium, the amount of deformation of the spray nozzle 2 due to the temperature rise is large (as a result, problems such as a drop in the spray pressure, which inhibits stable spraying and worsens the fine powder yield, occur). Therefore, the molten metal nozzle 6 and the spray nozzle 2 could not be brought close to each other.

Therefore, the inventors of the present invention conducted studies to avoid this problem, and found that the heat insulation effect, which was conventionally obtained by the space between the molten metal supply device 1 and the spray nozzle 2, was replaced by a cooling means inside the spray nozzle 2. 8 thermally separates the spray nozzle 2 from the molten metal supply device 1 without increasing the distance between the spray nozzle 2 and the spray medium jet 9.
It was found that it is possible to prevent the temperature from rising and that it is possible to spray stably at a predetermined pressure.

This cooling means 8, for example, as shown in FIG.
-1, a water-cooled plate 8b provided on at least a part of the surface of the spray nozzle 2 facing the molten metal supply device 1;
By cooling the spray nozzle 2 (shown in the figure, which is provided above the spray nozzle 2), it is possible to avoid an increase in the temperature of the spray nozzle 2 due to heat dissipation from the molten metal supply device 1 such as the tundish 11].

In this cooling means 8, when the water cooling plate 8b was made of a copper alloy, the cooling effect was particularly large, but the invention is not limited to this.
The refrigerant is not limited to water either. Any known cooling means can be used as appropriate.

FIG. 12 shows the effects of the presence or absence of the cooling means 8 and the material of the water cooling plate 8b on the stability of the spray medium pressure. Tandish 1
After installing b, the spray medium pressure can be adjusted to 990 to 1000 kgf/cm2 by adjusting the opening amount of the spray nozzle 2.
Adjust the inner surface temperature of tundish 1b to 1200.
Molten steel that has been preheated to 6 degrees Celsius or higher and heated to 1,700 degrees Celsius is allowed to flow down to a temperature of about 2 degrees Celsius.
Water spraying was performed for 0 minutes. The equipment, the type of metal, etc. were all the same as in the case of FIG. 11, and the water cooling plate 8b was provided above the spray nozzle 2. FIG. 12 shows the average value of the spray medium pressure during spraying at this time. By providing the cooling means 8 in the spray nozzle 2, the pressure during spraying can be increased to + the initial adjustment value.
It can be stabilized within the range of 5 to -30 kgf/cm2, and it is possible to prevent the phenomenon in which the spray medium pressure decreases by 10% or more, which was observed in conventional devices.

The particle size of the powder obtained as a result of these sprays was 10
When the atomizing medium pressure is adjusted to 00±5 Jf/cm2, the particle size is 8.7 μm when using the device of the present invention equipped with cooling means 8, while it is 10.2 μm when there is no conventional cooling means.
m, and by providing a cooling means, it is possible to prevent a drop in spray medium pressure and to stably produce fine powder.

It is effective to make the diameter of the molten metal nozzle 6 smaller (thinner) for fine powder production, and the inventors invented a reduced pressure pouring method as a stable pouring spray method using a small diameter molten metal nozzle in Japanese Patent Application No. 1-50539. However, this reduced pressure pouring method was not possible with conventional equipment.

As a result of intensive studies by the present inventors in order to realize a device capable of carrying out such a reduced pressure pouring method, a gas supply pipe 10 was installed inside the spray nozzle 2 as shown in FIG. The molten metal supply device 1, the spray nozzle 2, and the spray medium jet 9 are substantially isolated from the outside air. Without increasing the distance ρ between the lower end of the IA nozzle 6 and the spray medium jet outlet 2b, the lower end of the molten metal nozzle 6 is approximately 8000 mm H2O from atmospheric pressure.
We have found that pressure adjustment over a wide pressure range can be achieved with good responsiveness.

With this pressure adjustment means, the present inventors' earlier application, Japanese Patent Application No.
As shown in No. 50539, it becomes possible to stably perform the pouring method from a small diameter nozzle of 3.5 mm or less.

In addition, as shown in FIG. 3, the spray chamber 3 and the slurry storage tank 5 that stores the spray medium slurry after spraying are separated, and a gas-liquid separation tank 4 is provided between them, thereby eliminating the spraying seen in conventional devices. It has been found that it is possible to prevent pressure fluctuations in the spray nozzle caused by pressure fluctuations in the spray tank caused by the collision of the spray medium slurry jet with the spray medium. This can prevent the spray medium jet 9 from becoming unstable due to airflow fluctuations.

The gas-liquid separation tank 4 includes a bent pipe section 4a continuous to the spray chamber 3, an inverted conical tank 4b, and its upper and bottom piping 4c.
, 4d. After the spray medium slurry flowing down from the spray chamber 3 at high speed is deflected by the bent pipe section 4a, it enters the inverted conical tank 4b obliquely downward from the side thereof. The slurry that has entered the tank 4b is rotated to separate the accompanying gas and then to the slurry discharge pipe 4d at the bottom.
is discharged from. Also, the gas is supplied to the pipe 4c at the top of the tank.
more excreted.

Due to this action, it is possible to keep the airflow in the tank 4b stable at all times, and the pressure in the spray chamber 3 is also stabilized.

In this manner, the apparatus of the present invention is capable of more stable spraying by providing the gas-liquid separation tank 4.

<Example> The present invention will be specifically explained below based on Examples.

(Example 1) Fine powder was manufactured using the metal powder manufacturing apparatus of the present invention shown in FIGS. 1 and 2.

The water cooling plate 8b was made of a prepared alloy and was cooled by flowing water at a rate of 5° C./min so that the temperature of each part of the spray nozzle 2 was 80° C. or less.

Using a high frequency melting furnace, stainless steel scrap was used as a base material and an alloy material was added to adjust the composition to obtain a composition of 5US316L, which was then melted.

After heating the obtained molten metal to 1650°C, the surface temperature was 12
Tundish preheated to 00℃ or higher], melting furnace 1 in b
A was tilted and injected. The inner side of the rindishcoat 1b was made of cement mainly composed of magnesia, and the outer surface was made of a heat insulating material to prevent heat radiation. In addition, each molten metal nozzle 6 made of alumina or zirconia and having a diameter of 16 to 4 mm is installed at the bottom of the tundish 1b.
was installed.

When the diameter of the molten metal nozzle 6 was 3.5 mmφ or less, a reduced pressure pouring method was used to avoid solidification and clogging at the molten metal nozzle. For example, when the diameter of the molten metal nozzle 6 is 3 mmφ, the pressure at the bottom of the molten metal nozzle 6 is -11000 mm relative to the atmospheric pressure at the start of pouring.
820 or less, same during pouring <-300mm H2O
was held at This pressure was lower (closer to vacuum) as the diameter of the molten metal nozzle 6 was smaller, and after the start of pouring, it was gradually brought closer to atmospheric pressure to adjust the amount of poured metal per hour.

200 kg of molten metal is sprayed in about 25 minutes, and the flowing slurry passes through the gas-liquid separation tank 4, or is temporarily stored in the slurry storage tank 5 without the gas-liquid separation tank 4, and then is heated while preventing particles in the slurry from settling. After dehydration using a centrifugal sedimentation type dehydrator, the mixture was dried using a steam external heat type vacuum mixing dryer.

The particle size of the dried powder was measured using a particle size distribution measuring device "Microtrac" manufactured by Nikkiso Co., Ltd., and each was compared.

The pressure in the molten metal nozzle 6 is measured by a pressure measuring device using a strain gauge through a pressure measuring tube provided on the side wall of the spray medium jet 1 to the spout 2b, and the amount of nitrogen or air supplied from the gas supply tube 10 is measured. The pressure was adjusted or the gas supply pipe 10 was not used.

The same process as in Example 1 was carried out except that the distance ρ between the lower end of the molten metal nozzle and the spray medium jet outlet of the spray nozzle exceeded twice the maximum diameter d of the spray medium jet, and the process was carried out except that the spray nozzle cooling means was not provided. A sample treated in the same manner as in Example 1 and a sample treated in the same manner as in Example 1 except that the temperature was less than twice d and no spray nozzle cooling means were also carried out.

Table 1 shows the results of manufacturing fine stainless steel powder using the metal powder manufacturing apparatus of the present invention and the results of comparative examples.

As shown in the table, in the comparative example, in the case of low pressure spraying (comparative example 6
) and Comparative Example 2, in which the nozzle was brought closer, in all examples, 20 to 60% blockage occurred at the spray medium jet outlet.

However, in the example of the present invention in which the distance ρ between the lower end of the molten metal nozzle and the spray medium jet outlet was set to be less than twice the maximum diameter d of the spray medium jet, this blockage was completely eliminated.

Here, in Comparative Example 2 where the nozzle was placed close, the blockage could be prevented, but since there was no cooling structure, the water pressure decreased, and water cooling was performed.
Compared to Inventive Example 4 under the same conditions, the water pressure was lowered, the particles became coarser, and the yield of classified powder with an average particle size of 10 LLm was inferior. This tendency is the same when comparing Example 2 of the present invention and Comparative Example 1. Example 1 of the present invention solves the conventional problems by proximity of the molten metal nozzle and the spray nozzle and by providing a cooling structure to the spray nozzle. This avoids the phenomenon of solidification and clogging of the molten metal at the spray medium jet outlet and the drop in spray pressure when the nozzle comes into close contact, and enables stable spraying at a predetermined pressure, resulting in powder with the desired particle size.

Further, comparison will be made between Example 6 of the present invention, in which the molten metal nozzle was depressurized to -1000 mmH20 relative to the initial atmospheric pressure of pouring, and Example 7 of the present invention, in which a normal pouring method was used. In Inventive Example 6 using the reduced pressure pouring method, stable injection was possible in all cases, but in Inventive Example 7 in which melt was poured using the normal method, 60% of the molten metal nozzle was blocked. Further, although not shown in the table, it was difficult to pour molten metal using the normal pouring method when the molten metal nozzle diameter was 3.5 mm or less.
In Examples 1 to 5 of the present invention, in which the molten metal nozzle diameter was small, fine powder of 1071 m or less was obtained, and the yield of classified powder was also superior to that of Examples 6 to 8 of the present invention.

Therefore, the present invention makes it possible to adjust the pressure at the lower end of the molten metal nozzle using the exhaust action of the spray medium jet and the gas supply device, and by reducing the pressure in this part of the atmosphere at the initial stage of molten metal pouring, it becomes possible to pour molten metal into a small diameter, resulting in high Fine powder yield is possible.

4 Inventive Example 5 is an example in which a conventional spray tank was used without using a gas-liquid separation tank, but compared to the spraying results under the same conditions using a gas-liquid separation tank, the amount of particles with a diameter of 40 μm or more was 17% There were many.

In addition, when using a conventional spray tank, pressure fluctuations occur in the spray tank, and even when the spray nozzles 6 are placed close together, spraying occurs when the molten metal nozzle diameter is 3 mm or more, the convergence angle is 40 degrees or more, and the spray medium jet diameter is 12 mmφ or less. Fluctuations in the airflow from the focal point of the medium jet sometimes caused a blow-up phenomenon, making the spray unstable. However, by installing a gas-liquid separation tank, the air flow at the bottom of the molten metal nozzle was stabilized, and blow-up could be prevented under the same conditions.

<Effects of the Invention> Since the present invention is configured as described above, in a metal powder manufacturing apparatus using a liquid spray method, the molten metal nozzle is structured to be close to the spray medium jet outlet, and the spray nozzle is provided with a cooling structure. This makes it possible to improve powder yield and stabilize properties through stable atomization.

In addition, the fine powder yield is excellent due to the exhaust effect of the spray medium jet, the sealing effect of the molten metal supply device, the spray nozzle, and the spray medium jet, and the small diameter molten metal nozzle pouring device that adjusts the pressure at the bottom end of the molten metal nozzle by gas supply. A metal powder manufacturing device was obtained.

By separating the spray chamber and spray medium slurry tank,
A metal powder manufacturing apparatus that can more stably obtain fine powder was obtained.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an overall example of the metal powder manufacturing apparatus of the present invention. FIG. 2 is a diagram showing one example of a molten metal supply device and a spray nozzle of the metal powder manufacturing apparatus of the present invention. FIG. 3 is an enlarged view of the spray chamber and gas-liquid separation tank in FIG. 2. FIG. 4 is a diagram showing a configuration example of a metal powder manufacturing apparatus using a general spraying method. Figures 5, 6, 7, 8, 9 and 10
The figure is a diagram for explaining the prior art. FIG. 11 is a graph showing the relationship between occlusion rate and f2/d. FIG. 12 is a diagram showing the effect of the cooling structure on the spray medium pressure. Explanation of symbols ■... Molten metal supply device, 1a... Melting furnace, 1b...
... Tundish, 2 river spray nozzle, 2a... Top surface of spray nozzle, 2b... Spray medium jet outlet, 8 3... Spray chamber, 4a... Bent pipe section, 4c... Upper piping, 5... Slurry storage tank, 6a... Easy pouring spout, 8... Cooling means, 8b... Water cooling plate, 8c... Supply and discharge means, 10... Gas supply pipe, 12... - Spray nozzle chamber, 13... Spray medium pressure booster, 15... Piping, 4... Gas-liquid separation tank, 4b... Tank, 4d... Lower piping, 6... Molten metal nozzle, 7 ... Molten metal flow, 8a... Waterway, 9... Spray medium jet, 11... Spray tank, 14... High pressure piping, 16... Gas supply pipe

Claims (3)

[Claims] (1) It has a molten metal supply device, a spray nozzle, a spray chamber, and a slurry storage tank, and the molten metal stream poured from the molten metal nozzle of the molten metal supply device is sprayed from the spray nozzle in the spray chamber. An apparatus for manufacturing metal powder by atomizing, pulverizing, and cooling with a liquid spray medium jet, wherein the distance l between the lower end of the molten metal nozzle and the spray medium jet outlet of the spray nozzle is equal to the maximum diameter d of the spray medium jet. , and further comprising a cooling means on at least a part of a surface of the spray nozzle facing the molten metal supply device. (2) A metal powder manufacturing apparatus characterized in that a pressure regulating gas supply means is provided in a space substantially cut off from outside air, which is constituted by the molten metal supply device, the spray nozzle, and the spray medium jet. (3) The metal powder manufacturing apparatus according to claim 1 or 2, further comprising a gas-liquid separation tank between the spray chamber and the slurry storage tank.