JP6928869B2 - Metal powder manufacturing equipment - Google Patents

Description

The present invention relates to a metal powder manufacturing apparatus used in a method for producing a metal powder called a water atomizing method.

As a method for producing metal powder, it is known that molten metal (called molten metal) is pulverized by an atomizing method. The metal powder manufacturing equipment that adopts the atomization method uses a high-pressure fluid, mainly water, as a spray medium, and uses a water jet that jets diagonally downward from the periphery of the molten metal that flows down, thereby producing the energy of the fluid. Is configured to concentrate and collide with the molten metal. The molten metal splits due to the collision energy of the water jet and becomes a fine metal powder. Such a metal powder manufacturing apparatus is described in, for example, Patent Documents 1 to 3.

FIG. 2 is a diagram showing an example of the configuration of a metal powder manufacturing apparatus. The metal powder manufacturing apparatus 101 has a storage container (also called a tundish) 102 for storing the molten metal 110 poured from the melting furnace 121, and a fluid nozzle 103 arranged below the storage container 102 via a predetermined space 120. Have. The fluid nozzle 103 is formed with an annular slit (small gap), and the water jet 119 ejected from the slit (small gap) pulverizes the molten metal flowing down from the storage container 102 through the molten metal nozzle 104.

Air flows into the space 120 from the surroundings by the water jet 119 ejected from the gap, and an air flow F (air flow) is formed in the path through which the molten metal 110 flows down, and the molten metal 110 is caused by the water jet 119. Guided to the center of. However, when the molten metal 110 comes into contact with this air, the temperature of the molten metal 110 may drop. Especially in high-melting-point metal such as melting point of pure iron and Fe-based alloy above 1500 ° C. or Ni-base heat-resistant alloy, since the temperature at which the molten metal is solidified is high, the ordinary metal powder production apparatus, in the middle of the stream of molten metal 110 In some cases, the airflow F generated by the water jet promotes cooling of the molten metal before pulverization to increase the viscosity, resulting in insufficient splitting thereafter, making it impossible to produce a metal powder having a desired particle size.

In Patent Document 4 and Patent Document 5, as shown in FIG. 3, the molten metal nozzle 104 connected to the lower surface of the storage container 102 extends close to the water jet 119. If the section in which the molten metal 110 is directly exposed to the air flow F is shortened, it is possible to reduce the cooling of the molten metal by the air flow F.

Further, in Patent Document 6, as shown in FIG. 4, the molten metal nozzle 104 connected to the lower surface of the storage container 102 is covered with a protective pipe 105 arranged at a predetermined interval, and the air flow F by the water jet 119 is directly directed to the molten metal nozzle 104. I'm less exposed to.

A metal material such as iron, titanium, or copper having high thermal conductivity is used for the protective tube 105, and by providing the protective tube 105 in contact with the lower surface of the storage container 102, heat on the storage container 102 side can be generated. It is used to heat the protective tube 105. Further, a heating means is added to heat the protective tube 105, so that even if the protective tube 105 is cooled by the air flow F, it is compensated for.

Further, the gap between the molten metal nozzle 104 and the protective tube 105 is configured such that the upper end on the storage container 102 side is closed and the lower end on the fluid nozzle 103 side is open. It reduces the direct exposure of the airflow F by the water jet 119 to the molten metal nozzle 104, and further reduces the pressure in the gap by the airflow F to maintain the reduced pressure state, thereby improving the heat insulating property and melting through the molten metal nozzle 104. It suppresses the temperature drop of the metal and suppresses the increase in its viscosity.

Special Publication No. 43-6389 Japanese Unexamined Patent Publication No. 60-152605 International Publication No. 1999/011407 Japanese Unexamined Patent Publication No. 2-198620 Japanese Unexamined Patent Publication No. 2007-247054 Japanese Unexamined Patent Publication No. 2012-201941

The metal powder manufacturing apparatus of Patent Documents 4 to 6 has a structure in which the molten metal nozzle 104 extends from the storage container 102 to a position close to the gap of the water jet. Although the molten metal nozzle 104 is heated by the heat of the storage container 102 and the molten metal 110, the longer the molten metal nozzle 104, the lower the temperature at the lower end on the fluid nozzle 103 side. The viscosity may increase and the amount of the molten metal 110 passing through the molten metal nozzle 104 may fluctuate, or the molten metal 110 may solidify in the molten metal nozzle 104 and cause clogging. Further, the molten metal nozzle 104 needs to be replaced every time the molten metal 110 is discharged, but the molten metal nozzle 104 made of a ceramic material such as alumina or zirconia, which has a relatively low thermal conductivity as compared with a metal-based material, has a molten metal nozzle 104. The longer the length, the more difficult and expensive it is to manufacture, and it also becomes a factor that increases the manufacturing cost.

Further, in the metal powder manufacturing apparatus of Patent Document 6, a protective tube 105 covering the molten metal nozzle 104 is provided in contact with the lower surface of the storage container 102, but the heat insulating structure between the storage container 102 side and the fluid nozzle 103 side is complicated. In addition, the molten metal nozzle 104 is cooled by the air flow F to take heat from the storage container 102 side, which may cause a problem such as a local decrease in the molten metal temperature.

Therefore, an object of the present invention is to provide a metal powder manufacturing apparatus capable of stably producing metal powder with excellent productivity by reducing the influence of the air flow in the path through which the molten metal flows and suppressing clogging of the molten metal nozzle. be.

The present invention has a storage container for storing molten metal, a molten metal flow path for flowing the molten metal in the vertical direction from the storage container, and a fluid having a gap for ejecting a fluid for pulverizing the molten metal toward the molten metal flow path. A metal powder manufacturing apparatus having a nozzle, which is provided at the lower part of the storage container and constitutes the molten metal flow path, and is provided on the lower side of the molten metal nozzle and has a molten fluid flow rather than the molten metal nozzle. A tubular molten metal guide constituting a molten metal flow path having a large cross-sectional area of the path and a windshield portion covering the outside of the molten metal guide are provided, and the fluid nozzle has a through hole directly below the molten metal guide and the penetration. The hole is provided with a reduced diameter portion in the direction from above toward the narrow gap, constitutes a flow path of an air flow generated by the ejection of the fluid between the reduced diameter portion and the windshield portion, and the lower end portion of the molten metal guide is formed. , A metal powder manufacturing apparatus that protrudes from the windshield portion toward the through hole side and is located between the upper end of the fluid nozzle and the gap of the fluid nozzle.

In the present invention, it is preferable to have a heating means on the outside of the molten metal guide and cover the heating means with the windshield portion.

Further, in the present invention, it is preferable to insert and arrange the lower end of the molten metal nozzle on the upper end side of the molten metal guide.

According to the present invention, it is possible to provide a metal powder manufacturing apparatus capable of stably producing metal powder with excellent productivity by reducing the influence of the air flow in the path through which the molten metal flows and suppressing clogging of the molten metal nozzle. ..

It is sectional drawing of the metal powder manufacturing apparatus which concerns on one Example of this invention. It is sectional drawing of the conventional metal powder manufacturing apparatus. It is sectional drawing of another conventional metal powder manufacturing apparatus. It is sectional drawing of another conventional metal powder manufacturing apparatus.

Hereinafter, the metal powder manufacturing apparatus according to the embodiment of the present invention will be specifically described. However, the present invention is not limited to this. In addition, in a part or all of the figure, a part unnecessary for explanation is omitted, and there is a part shown by enlargement or reduction for facilitation of explanation. Further, the dimensions and shapes shown in the description, the relative positional relationship of the constituent members, and the like are not limited thereto unless otherwise specified. Further, in the description, members of the same or the same quality are shown with the same name and reference numeral, and detailed description may be omitted even if they are shown in the figure.

FIG. 1 is a vertical cross-sectional view showing an embodiment of the metal powder manufacturing apparatus of the present invention. The metal powder manufacturing apparatus 1 shown in FIG. 1 is divided into a storage container side, a fluid nozzle side, and an intake portion between them. This device is used to crush the molten metal 10 with a spray medium made of water or the like, cool the crushed molten metal with a cooling medium such as water to pulverize it, and inject the molten raw material that melts and flows down from a nozzle. It is crushed with high-pressure water to make a powder, and also cooled to obtain a powder. The obtained powder is composed of large and small particles widely distributed, for example, from submicrons to several hundreds of microns.

The metal powder manufacturing apparatus 1 has a storage container 2 for temporarily storing the molten metal 10 poured from a melting furnace (not shown), a molten metal nozzle 4 provided on the bottom surface thereof, and the molten metal nozzle on the storage container 2 side. It has a molten metal guide 5 provided below the molten metal guide 5 and a fluid nozzle 3 for crushing the molten metal 10 flowing out from the molten metal guide 5, and further, a heating means 12 such as a heater is provided on the outside of the molten metal guide 5. A windshield portion 11 is provided so as to cover the outside of them.

The fluid nozzle 3 is provided in the main body portion, a through hole 22 provided in the main body portion and serving as a molten metal flow path through which the molten metal 10 flowing down from the storage container 2 passes, and a thin hole 22 for injecting a water jet 19 toward the through hole 22. It has a gap 23. The through hole 22 is also a flow path 20 of the air flow F formed by the water jet. The through hole 22 has a reduced diameter portion that penetrates the main body portion of the fluid nozzle 3 in the vertical direction and whose diameter is continuously reduced toward the gap 23. Specifically, the intake portion is continuous from the space 20 between the storage container 2 and the fluid nozzle 3, has the largest opening at the upper part of the fluid nozzle 3 on the storage container 2 side, and decreases toward the lower gap 23. ing. Below the narrow gap 23, the diameter increases downward. The through hole 22 has a circular shape when viewed in the vertical direction, and the fluid nozzle 3 is arranged so that the center thereof coincides with the center of the molten metal flow path, which is the path of the molten metal 10 flowing down from the storage container 2.

The main body portion of the fluid nozzle 3 is formed by overlapping the upper cylinder 25 and the lower cylinder 26. A high-pressure fluid of 50 to 200 MPa supplied from a fluid supply source (not shown) of an external pump device or the like through a connection path such as a hose is connected to the fluid passage 24 and a circle that opens to the through hole 22 side. It is injected into the molten metal 10 flowing down from the gap 23 through the annular introduction path 27 to form a conical water jet 19. The fluid nozzle 3 is not particularly limited as long as it is a material having heat resistance and pressure resistance that can withstand the pressure of the fluid, but it is preferably made of a metal material.

As shown in FIG. 1, the bottomed storage container 2 is in a state where the periphery is filled with zircon sand (not shown), and the periphery thereof is a mica board having excellent electrical insulation and heat resistance (FIG. 1). It is surrounded by (not shown), and an induction coil (not shown) is further arranged. The temperature of the molten metal 10 poured from the melting furnace by heating with an induction coil is adjusted to be within a predetermined range. The storage container 2 may be a material that is not deformed by the molten metal 10, and for example, various ceramic materials such as alumina and zirconia, graphite, and the like are used. Further, a through hole is provided at the bottom of the storage container 2, and the molten metal nozzle 4 is fitted into the through hole by screw coupling or the like. Zircon sand is used for fixing the storage container and for heat retention / heat insulation, and alumina sand or the like may also be used. The molten metal nozzle 4 is opened and closed by a ceramic rod 35.

As shown in FIG. 1, the molten metal nozzle 4 is a long tubular member having a hole through which the molten metal nozzle 4 linearly penetrates, and the molten metal 10 stored in the storage container 2 is allowed to flow downward through the hole. The shape of the molten metal nozzle 4 is not particularly limited as long as it has a tubular shape, and can be appropriately set in consideration of attachability to the storage container 2, heat resistance and impact resistance, and the like. The opening shape of the hole is preferably circular, and the cross section in the length direction is preferably a taper that is wider on the storage container 2 side and narrows toward the bottom, and is preferably straight from the narrowest portion. The particle size of the obtained metal powder (defined by the median diameter d50, which is the particle size at which the cumulative% from the small diameter side is 50% by volume from the volume-based particle size distribution measured by the laser diffraction method) is generally determined by the molten metal nozzle 4. Affected by inner diameter. Therefore, when the median diameter of the target metal powder is about 1 to 20 μm, the inner diameter of the narrowest portion of the hole is preferably about 1 to 5 mm. Various ceramic materials such as alumina, zirconia, mullite, and boron nitride are used for the molten metal nozzle 4.

Around the molten metal nozzle 4, for example, a ceramic member 16 for heat insulation such as alumina that can be arranged in a cylindrical shape around the molten metal nozzle 4 is arranged. In the illustrated example, an alumina sleeve is used, and a highly heat-resistant sealing member such as graphite is attached to the attachment portion of the molten metal nozzle 4 to the storage container 2 so as to be sandwiched between the upper end side of the ceramic member 16 and the bottom side of the storage container 2. (Not shown) is provided. Further, in order to insulate the fluid nozzle 3 side, a heat insulating member 28 such as a fiber board is spread on the bottom of the storage container 2, and a water-cooled copper plate 17 for cooling is provided under the heat insulating member 28 to improve the heat insulating property. The lower end of the molten metal nozzle 4 is set so as not to protrude from the water-cooled copper plate 17. The thickness of the heat insulating member 28 such as the fiber board is preferably 1 to 5 cm in consideration of the heat insulating property and the small size and space saving of the metal powder manufacturing apparatus. In addition to the fiber board, the heat insulating member 28 may be formed by laying an alumina block and filling the space between them with zirconia sand.

Below the molten metal nozzle 4, a long and tubular molten metal guide 5 for passing the molten metal 10 that has passed through the molten metal nozzle 4 is arranged. It is preferable that the center of the hole of the molten metal guide 5 is provided so as to coincide with the center of the hole of the molten metal nozzle 4. The cross-sectional area of the hole of the tubular molten metal guide 5 is larger than that of the molten metal nozzle 4, and the lower end side of the molten metal nozzle 4 is the hole of the molten metal guide 5 so that the upper end of the molten metal guide 5 surrounds the lower end of the molten metal nozzle 4. It is inserted on the upper end side. The lower end is set to a position that extends close to the fluid nozzle. As the material constituting the molten metal guide 5, iron-based materials such as heat-resistant steel, various ceramic materials such as alumina, zirconia, mullite, and boron nitride having excellent heat-resistant impact resistance are used. The shape of the molten metal guide 5 is not particularly limited as long as it is tubular, but a cylindrical shape is preferable from the viewpoint of ease of formation, and a flange portion may be provided on the upper end side to facilitate assembly. When the molten metal guide 5 has the above configuration, as shown in FIG. 1, the molten metal guide 5 is arranged so as to be inserted into the recess on the lower side of the water-cooled copper plate 17 for cooling, and the flange portion thereof. Can be screw-fixed to the water-cooled copper plate 17 with the holding plate 18. The molten metal guide 5 can be easily attached only by fixing the upper end, and the work of removing the molten metal guide 5 becomes easy.

It is preferable that the lower end of the molten metal guide 5 is arranged in the through hole 22 and is located between the upper end of the fluid nozzle 3 and the gap 23. With this arrangement, the molten metal 10 can be supplied close to the water jet 19 while avoiding the influence of the air flow F by using the hole of the molten metal guide 5 as the molten metal flow path. The water jet 19 has a conical shape whose basic apex is downward, but in the vicinity of the gap 23, the water jet 19 may be blown upward together with a partially split molten metal. The blown molten metal may adhere to the lower end of the molten metal guide 5, but a position where the molten metal guide 5 to the water jet 19 can be secured without blocking the molten metal guide 5 is a guideline for the lower end of the molten metal guide 5.

By configuring the molten metal 10 to pass through the hollow portion of the molten metal guide 5, it is not necessary to extend the molten metal nozzle 4 to the vicinity of the gap 23, and even if it is shortened, the molten metal 10 in the storage container 2 can be stably fluidized. It can supply up to the vicinity of the gap of the nozzle 3. Further, by shortening the molten metal nozzle 4, the possibility that the molten metal 10 is clogged can be reduced.

The inner space into which the molten metal 10 of the molten metal guide 5 flows down also functions as a heat insulating layer, and an increase in the viscosity of the molten metal 10 can be suppressed. Further, when the water jet 19 is formed by the high-pressure fluid, an air flow from the upper side to the lower side of the gas flow path 20 is generated accordingly. Due to this air flow F, the inner space of the molten metal guide 5 tends to be in a decompressed state. In Patent Document 6, the pressure in the gap between the molten metal nozzle 104 and the protective tube 105 is reduced by the air flow F sucked by the water jet to maintain the decompressed state, thereby improving the heat insulating property of the gap. Similar effects are likely to be obtained in the invention.

Further, a windshield portion 11 is provided on the outside of the molten metal guide 5. The windshield portion 11 is open so as to pass through the lower end side of the molten metal guide 5, and is on the top plate 30 side which is a part of the intake portion forming the flow path 20 of the air flow F so as to cover substantially the entire molten metal guide 5. Attached to.

Further, the shape of the windshield portion 11 is streamlined to follow the shape of the through hole 22 of the fluid nozzle 3 to prevent the airflow F from being obstructed. The molten metal 10 flowing down from the molten metal guide 5 is sent to the water jet 19 together with the stable air flow F, and can be pulverized under good conditions. It is preferable to use an iron-based material such as heat-resistant steel or a metal material such as stainless steel for the windshield portion 11 because of its ease of processing into its shape.

The molten metal guide 5 may be provided with a heating means 12 such as a heater. The heating means 12 is preferably provided below the lower end of the molten metal nozzle 4 and near the middle of the molten metal nozzle 4 in the longitudinal direction. By heating the molten metal guide 5 by this heating means, it is possible to more reliably suppress the temperature drop of the molten metal 10. Further, when the molten metal 10 is scattered on the molten metal guide 5, the possibility of cracking due to thermal shock is reduced. Further, it is preferable to cover the entire heating means 19 with the windshield portion 11 so as to increase the heating efficiency. The heating means 12 may be attached to the top plate 30. Further, the top plate 30 may be provided with a connection cable to the heating means 12, a groove for arranging a thermocouple for temperature measurement, or the like.

In the metal powder manufacturing apparatus having such a configuration, the molten metal 10 is allowed to flow down from the short molten metal nozzle 4, and the molten metal 10 flowing down from the molten metal nozzle 4 is configured to pass through the hollow portion of the molten metal guide 5. The molten metal 10 in 2 is supplied from the molten metal nozzle 4 to the fluid nozzle 3 through the molten metal guide 5. Therefore, the temperature drop of the molten metal 10 can be suppressed and the molten metal 10 can be stably supplied to the vicinity of the gap of the fluid nozzle 3. Further, it is not necessary to extend the molten metal nozzle 4 to the vicinity of the gap 23 of the fluid nozzle 3, and shortening the molten metal nozzle 4 reduces the possibility of clogging of the molten metal 10 and does not impair productivity. In the molten metal split by the water jet 19, fine metal powder is recovered as a slurry, and the metal powder can be stably produced.

1 Metal powder manufacturing equipment 2 Storage container 3 Fluid nozzle 4 Molten nozzle 5 Molten guide 10 Molten 11 Windshield 12 Heating means 15 Induction coil 19 Water jet 20 Flow path 22 Molten flow path 23 Nipple 24 Fluid passage 25 Fluid nozzle Upper cylinder 26 Lower cylinder of fluid nozzle 27 Circular introduction path

Claims (3)

A storage container for storing molten metal and
A molten metal flow path that allows the molten metal to flow vertically from the storage container,
A metal powder manufacturing apparatus comprising a fluid nozzle having a gap for ejecting a fluid for pulverizing the molten metal toward the molten metal flow path.
A molten metal nozzle provided at the bottom of the storage container and forming the molten metal flow path, and a molten metal nozzle.
A tubular molten metal guide provided on the lower side of the molten metal nozzle and forming a molten metal flow path having a larger cross-sectional area of the molten metal flow path than the molten metal nozzle.
And a windshield portion covering the outside of the molten metal guide,
The lower end side of the molten metal nozzle is inserted into the upper end side of the hole of the molten metal guide.
The fluid nozzle has a through hole directly below the molten metal guide, and the through hole has a reduced diameter portion in a direction from above toward the gap, and the reduced diameter portion and the windshield portion of the fluid. It constitutes the flow path of the airflow generated by the ejection,
A metal powder manufacturing apparatus in which the lower end of the molten metal guide projects from the windshield toward the through hole and is located between the upper end of the fluid nozzle and the gap of the fluid nozzle. The metal powder manufacturing apparatus according to claim 1.
A metal powder manufacturing apparatus having a heating means on the outside of the molten metal guide and covering the heating means with the windshield portion. The metal powder manufacturing apparatus according to claim 2.
A metal powder manufacturing apparatus in which the lower end of the molten metal nozzle is inserted into the upper end side of the molten metal guide.

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