WO1992021462A1

WO1992021462A1 - Method and device for making metallic powder

Info

Publication number: WO1992021462A1
Application number: PCT/JP1992/000710
Authority: WO
Inventors: Naotsugu Isshiki; Hiroshi Izaki; Yosimitsu Tokunaga; Syoichi Yoshino; Masanori Yoshino; Toshiyuki Aoki
Original assignee: Kubota Corporation
Priority date: 1991-06-05
Filing date: 1992-06-01
Publication date: 1992-12-10
Also published as: AU1776892A; EP0543017A4; AU645908B2; DE69224505T2; DE69224505D1; CA2088054C; KR0174749B1; EP0543017A1; EP0543017B1; CA2088054A1

Abstract

A method and a device for making metallic powder, by which irregularity in cooling speed is hardly caused, high speed cooling and solidification are made possible, and fine grain powder can easily be obtained. Cooling liquid is spouted along the inner peripheral surface of a cooling cylinder (1) so that a cooling liquid layer (9) is formed which moves while turning along the inner peripheral surface of said cylinder (1), toward the side of a cooling liquid discharging end of said cylinder (1); molten metal (25) is supplied into the inner space (23) inside said cooling layer (9); jetting gas (26) directed toward the cooling liquid layer (9) is blown to said molten metal (25) for fragmentation and molten metal thus fragmented is supplied to the cooling liquid layer (9); and cooling liquid containing metallic powder solidified in the cooling liquid layer (9) is discharged from the discharging end of the cooling cylinder (1) to the outside.

Description

Specification

Method and apparatus for producing metal powder

【Technical field】

The present invention relates to a method and an apparatus for producing a metal powder by supplying a molten metal into a swirling cooling liquid layer.

[Background Art]

Since the rapidly solidified metal powder has fine crystal grains and can contain alloying elements in supersaturation, the extruded material formed by the rapidly solidified powder and the sintered material are excellent materials that are not provided by the ingot material. It has properties and is attracting attention as a material for mechanical parts.

As a method for producing the rapidly solidified metal powder, there is a rotating drum method as disclosed in Japanese Patent Publication No. 1-49769. In this method, a bottomed cooling drum containing a cooling liquid is rotated, a cooling liquid layer is formed on the inner peripheral surface of the cooling drum by the action of centrifugal force, and a molten metal is jetted into the cooling liquid layer. This is a method of obtaining rapidly solidified metal powder by dividing by a rotating cooling liquid layer.

On the other hand, U.S. Pat.Nos. 4,787,935 and 4,869,469 disclose a method of gas atomizing a molten metal stream and then turning the atomized spherical droplets while rotating in a cooling cylinder. A method and an apparatus for producing a metal powder to be supplied to a spiral flow and cooled and solidified are disclosed.

According to the rotary drum method, a so-called batch operation is performed, and there is a problem that productivity is poor. In addition, since the number of rotations of the cooling drum is limited, it is difficult to increase the flow rate of the cooling liquid layer, and it is difficult to obtain fine powder.

On the other hand, according to the production method of the above-mentioned US patent, it is possible to continuously produce from a fine powder having a particle size of 0.1 粒径 α to a coarse powder having a particle size of about 1000 IB. However, in this manufacturing method, the cooling rate is about 10 ² to 10 ^{7 e} C / sec. No quenching effect is obtained. In addition, the droplet at the center of the spiral flow of the cooling gas is not easily swirled, and the cooling rate is reduced, so that the quality of the produced powder tends to vary. In addition, in order to form a spiral flow of cooling gas suitable for cooling droplets in the cooling cylinder, the cooling cylinder must be made considerably large, and this can be easily performed in terms of installation location and equipment costs. There is a problem that it is difficult to implement.

The present invention has been made in view of such a problem, and provides a method of manufacturing a metal powder and a method of producing a metal powder that can be rapidly solidified at a high cooling rate without causing a variation in a cooling rate and a fine powder can be easily obtained. An object of the present invention is to provide a suitable manufacturing apparatus for carrying out the method.

DISCLOSURE OF THE INVENTION

In the method for producing metal powder according to the present invention, a cooling liquid is jetted and supplied along an inner peripheral surface of a cooling cylinder, and is swirled along a peripheral surface of the cylinder toward a cooling liquid discharge end of the cylinder. Forming a moving cooling liquid layer; supplying a molten metal to a space inside the cooling liquid layer; blowing a gas jet toward the cooling liquid layer on the molten metal to separate the molten metal and splitting the molten metal; The metal is supplied to the coolant layer; the coolant containing the metal powder solidified in the coolant layer is discharged to the outside from the coolant discharge end of the cylinder. When discharging the cooling liquid containing metal powder to the outside, the cooling liquid is discharged to the outside while filling the inside of the pipe from the discharging pipe provided in the closing lid provided at the cooling liquid discharging end of the cylindrical body. Is good.

In addition, the manufacturing apparatus of the present invention includes: a cooling cylinder provided with a coolant ejection flow path for ejecting and supplying a coolant along an inner peripheral surface; and a cooling cylinder ejected from the coolant ejection flow path. The molten metal floods the space inside the coolant layer formed so that the coolant moves toward the coolant discharge end of the cylinder while rotating along the inner peripheral surface of the cylinder. Means for supplying molten metal; and supplying the molten metal to the cooling liquid layer while dividing the molten metal. And a cooling liquid supply means for supplying a cooling liquid to the cooling liquid discharging flow path. It is preferable that the cooling cylinder is provided with a closing lid at a cooling liquid discharge end, and the lid is provided with a discharge pipe for discharging the cooling liquid in a state where the cooling liquid is filled in the pipe.

According to the present invention, the cooling liquid ejected and supplied from the cooling liquid ejection flow path along the inner peripheral surface of the cooling cylinder rotates while flowing along the inner peripheral surface of the cylinder, and the cooling liquid discharge end of the cylinder is discharged. Move towards the opening. At this time, a cooling liquid layer having a substantially constant inner diameter is formed on the inner peripheral surface of the cylinder by the action of the centrifugal force during the turning. Since this cooling liquid layer is always formed by the newly supplied cooling liquid, a constant temperature is easily maintained. Further, since the cooling medium is a liquid, the cooling medium is excellent in the cooling ability as compared with the gas. As the cooling liquid layer, a turning layer having a small turning radius and a small layer thickness is sufficient, and the cooling cylinder that forms the cooling liquid layer is also compact.

The molten metal supplied from the molten metal supply means to the space inside the coolant layer is blown by the gas jet ejected from the gas jet ejection means toward the coolant layer and is divided. The separated molten metal (droplets) scatters toward the coolant layer, and all droplets are reliably injected and supplied into the coolant layer. The droplet injected into the cooling liquid layer generates vapor of the cooling liquid around it, and this vapor is quickly released from around the droplet. The reason is that since the distribution of the flow velocity in the cooling liquid layer has a gradient velocity distribution that increases toward the center of rotation, the droplets injected into the cooling liquid layer rotate. Therefore, since the outer peripheral surface of the droplet always comes into contact with the cooling liquid, the droplet is cooled at a high cooling rate and the contamination of the powder particle surface by the vapor is prevented. In addition, by controlling the flow rate and flow rate of the gas jet, the size of the separated droplets can be easily adjusted. A coagulated fine powder can be easily obtained. In addition, since the temperature and surface condition of the cooling liquid layer are constant and stable, the cooling conditions for the droplets are constant and the quality of the powder is stable.

Since the cooling liquid layer is formed continuously, continuous production of powder becomes possible by continuously supplying molten metal, continuously blowing and separating gas jet to supply the cooling liquid layer. . The metal powder solidified in the cooling liquid layer is continuously discharged together with the cooling liquid from the cooling liquid discharge end opening of the cooling cylinder.

When discharging the cooling liquid containing the metal powder, a closing lid is provided at the opening of the cooling liquid discharge end of the cooling cylinder, and the cooling liquid is discharged from the discharge pipe provided in the closing lid into the pipe. It is good to discharge to the outside while satisfying. According to this method, the empty portion inside the cooling liquid layer can be easily filled with the gas forming the gas jet. By using a suitable non-oxidizing gas such as an inert gas or a reducing gas as this gas, oxidation of the droplet can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a metal powder production apparatus according to an embodiment. FIG. 2 is a sectional view of a main part of the same device according to another embodiment. FIG. 3 is a cross-sectional view of a main part of the same device according to the third embodiment. FIG. 4 is a sectional view of a main part of the same device according to the fourth embodiment. FIG. 5 is an explanatory sectional view of the continuous pouring apparatus. Figure 6 is an overall layout diagram of the continuous metal powder production facility. FIG. 7 is a sectional view of a main part of a metal powder manufacturing apparatus used in a manufacturing example of the present invention. FIG. 8 is a plan view showing the positional relationship between the trickled molten metal and the gas jet in the production example. FIG. 9 is a graph showing the particle size distribution of metal powders produced according to the production example and the production comparative example. FIG. 10 is a graph showing the relationship between the particle size of the metal powder produced according to the production example of the present invention and the cooling rate. BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 shows a metal powder production apparatus according to an embodiment, in which a cooling cylinder 1 for forming a cooling liquid layer 9 on the inner peripheral surface and a space 23 inside the cooling liquid layer 9 are melted. A crucible 15 as a molten metal supply means for supplying the metal 25 downflow, a pump 7 as a means for supplying a cooling liquid to the cylindrical body 1, and a trickle-shaped molten metal 25 flowing down into droplets A jet nozzle 24 is provided as gas jet ejection means for ejecting a gas jet 26 for dividing and supplying the gas jet 26 to the cooling liquid layer 9.

The cylindrical body 1 has a cylindrical shape, and a cylindrical axis is installed in a vertical direction. An annular lid 2 is attached to an upper end opening of the cylindrical body 1. An opening 3 for supplying the inside of 1 is formed. Further, a plurality of cooling liquid ejection pipes 4 having a cooling liquid ejection flow path 5 are formed at equal intervals in a circumferential direction on the upper part of the cooling cylinder 1, and an outlet (discharge port) of the flow path 5 is provided at the cylinder 1. An opening is provided along the inner peripheral surface so that coolant can be ejected and supplied from the tangential direction. Centerline that put the opening of the channel 5 is set to 0 to 20 ^beta approximately obliquely lower side with respect to a plane perpendicular to the cylindrical body axis. The coolant jet pipe 4 is connected to a tank 8 via a pump 7, and the coolant in the tank 8 is drawn up by the pump 7 to be cooled from a coolant jet channel 5 of the jet pipe 4. By jetting and supplying to the inner peripheral surface side of the cylindrical body 1, a cooling liquid layer 9 that flows down while rotating along the inner peripheral surface is formed on the inner peripheral surface of the cooling cylindrical body 1. The tank 8 is provided with a replenishing coolant supply pipe (not shown), and a cooler may be appropriately provided in the tank 8 or in the middle of the coolant circulation path. Water is generally used as the cooling liquid. This is because it has excellent cooling performance and low cost. In addition to water, liquids used in the quenching of heated metals such as oil may be used. When water is used, it is desirable to use water from which dissolved oxygen has been removed. Oxygen removal treatment Equipment is commercially available and readily available.

A layer thickness adjusting ring 10 for adjusting the layer thickness of the cooling liquid layer 9 is attached to the lower part of the inner peripheral surface of the cooling body 1 by a port so as to be detachable and replaceable. The flow rate is suppressed, and the coolant layer 9 having a substantially constant inner diameter is easily formed with a small flow rate. At the lower end opening, which is the cooling liquid discharge end of the cylindrical body 1, an R cylindrical liquid drain net 11 is continuously provided, and a funnel-shaped powder collecting container 12 is attached below the net 11. . A coolant recovery cover 13 is provided around the net 11 so as to cover the net 11, and a drain port 14 is formed at the bottom of the recovery cover 13, and the drain port 14 is provided via a pipe. Connected to tank 8.

A crucible 15 serving as a molten metal supply means disposed above the cooling cylinder 1 is formed of a refractory material such as graphite / silicon nitride, and has a bottomed cylindrical crucible body 16 and an upper end of the crucible body 16. And a lid 17 for closing the opening. An induction coil 18 for maturation is provided on the outer periphery of the crucible body 16, and a bottom-end 19 of the crucible body 16 is formed with a vertically extending nozzle hole 20 in a vertical direction. It faces the opening 3 of 2. Further, the lid 17 Ruth pot 15, the injection hole 21 for injecting a pressure medium Ya pumped molten metal inert gas ₂ such as A r and Ν is formed from injection hole 21 not By injecting the active gas or the like under pressure, the molten metal 22 in the crucible 15 is jetted from the nozzle hole 20 to the space 23 inside the cooling liquid layer 9 via the opening 3.

A jet nozzle 24 for ejecting a compressed gas such as air or an inert gas used in a normal gas atomizing method is disposed in an empty space 23 inside the cooling liquid layer 9. The nozzle 24 is attached to the tip of a compressed gas supply pipe 27 inserted through the opening 3 of the annular lid 2, and the nozzle of the nozzle 24 is connected to the coolant layer 9 and the nozzle hole 20 of the crucible 15. It is intended for the spouted molten metal 25. The outlet of the cooling liquid ejection flow path 5 is opened in the upper side of the cooling cylinder 1 in the figure, but when the distance between the outlet and the layer thickness adjusting ring 10 is long, the cooling liquid flow speed is reduced. Due to the increase, the thickness of the cooling liquid layer 9 tends to be concave at the center, so the outlet of the cooling liquid ejection flow path 5 is located at the center between the upper end of the cooling cylinder 1 and the upper surface of the layer thickness adjusting ring 10. It is preferable that the opening be provided between the upper surface of the ring 10 and the upper surface. Even if it is opened at such a position, the coolant is pushed up by the action of the centrifugal force above the outlet, and a coolant layer with a constant thickness almost similar to that below is formed.

In the above configuration, in order to produce metal powder, first, the pump 7 is operated to form the cooling liquid layer 9 on the inner peripheral surface of the cylindrical body 1, and then the molten metal 22 in the crucible 15 is discharged through the nozzle hole 20. Spouts downward from. At this time, the gas jet 26 is jetted from the jet nozzle 24 at a high speed. The gas jet 26 jetted from the jet nozzle 24 is sprayed on the trickled molten metal 25 jetted from the crucible 15, and the molten metal 25 is split, and the split droplets scatter toward the cooling liquid layer 9. Is done. The scattered droplets are injected into the cooling liquid layer 9 flowing down while turning, and rapidly solidified to produce metal powder. In this case, by appropriately setting the distance from the collision portion between the gas jet 26 and the molten metal 25 to the coolant layer 9, the shape of the powder particles can be changed from a spherical shape to a flat amorphous shape. That is, when the distance to the coolant layer 9 is reduced, the droplets separated by the gas jet 26 are injected into the coolant layer 9 before forming a solidified shell on the surface thereof, and are re-established by the coolant layer 9. Due to the fragmentation, fine amorphous powder is obtained. On the other hand, if the distance is sufficient, a solidified shell is formed on the surface of the droplet, so that even when injected into the cooling liquid layer 9, it can maintain a substantially spherical shape.

Then, the metal powder in the cooling liquid layer 9 flows down through the layer thickness adjusting ring 10 while rotating with the cooling liquid, and flows through the lower end opening of the cooling cylinder 1. Enter the drainage net 11. Here, the coolant scatters radially outward from the mesh body 11 by the action of the centrifugal force, and a metal powder with a small amount of liquid that has been temporarily removed is obtained. The metal powder subjected to the primary elimination enters the powder recovery container 12, is discharged therefrom, is eliminated by an elimination device such as a centrifuge, and is dried by a drying device. In addition, the coolant scattered from the net 11 is returned to the tank 8 through the recovery cover 13 and used for circulation. FIG. 2 shows another embodiment of the metal powder production apparatus, and the same members as those of the production apparatus of the above embodiment are denoted by the same reference numerals.

In this embodiment, the cooling cylinder 1 is arranged with the cylinder axis inclined. The cooling liquid ejection flow path 5 is opened directly in the thick cooling cylinder 1, and the inlet ′ of the cooling liquid ejection flow path 5 opened on the outer peripheral surface of the cooling cylinder 1 is connected to the pump 7 by piping. You. Further, a funnel-shaped closing lid 31 for closing the opening is attached to the lower end opening of the cooling cylinder 1, and a discharge pipe 33 is provided at the bottom thereof, and the inside thereof is provided with a cooling liquid. Discharge channel 32. A layer thickness adjusting ring 10 having an upper surface formed by a tapered surface is attached to a lower inner peripheral surface of the cooling cylinder 1 by a port. The discharge pipe 33 is piped such that the other end opening (outlet) is located above the tank 8, and a flow regulating valve 34 is provided in the middle of the pipe. A net basket 35 is detachably attached to the upper opening of the tank 8.

In the case of this embodiment, by appropriately adjusting the opening and closing of the flow control valve 34, the cooling liquid can be discharged in a state filled in the discharge flow path 32. In this case, gas can be prevented from flowing out from the discharge pipe 33, and the space 23 inside the coolant layer 9 of the cylinder 1 is filled with the gas of the gas jet 26 ejected from the jet nozzle 24. Can be. Therefore, by using a non-oxidizing gas such as an inert gas, the oxidation of the separated droplets can be effectively prevented. FIG. 3 shows a third embodiment of the metal powder manufacturing apparatus. In this embodiment, the cooling liquid jet passage 5 has a plurality of outlets (two stages) in the vertical direction on the inner peripheral surface of the cooling cylinder 1. It is open. The number of cooling fluid ejection passages 5 in the direction of the cylinder axis and the distance between them differ depending on the inner diameter of the cylinder, the amount of coolant discharged, the ejection pressure, the set distance of the lower layer thickness adjustment ring 10, etc., but are almost constant. An appropriate number of stages may be provided at substantially equal intervals so as to obtain a cooling liquid layer 9 having an inner diameter. In this embodiment, since a plurality of cooling liquid jet channels 5 are provided above the layer thickness adjusting ring 10, the cooling liquid layer 9 is formed above the ring 10 by increasing the flow rate of the cooling liquid. A reduction in thickness can be prevented, and a coolant layer 9 having a substantially constant inner diameter and a constant swirling flow velocity can be easily formed in a long range on the inner peripheral surface of the cylindrical body 1, and the cooling region is provided in a long range be able to. As shown in the figure, a layer thickness adjusting ring 10A may be provided between adjacent stages of the coolant ejection flow path 5 in the cylinder axis direction. Thereby, the thickness and the flow velocity of the cooling liquid layer 9 can be further stabilized. In addition, even if the cooling liquid ejection flow path 5 is provided in one stage and the ring thickness adjusting ring is provided in a plurality of stages, there is an effect of preventing a decrease in the thickness of the cooling liquid layer 9.

In the third embodiment shown in FIG. 3, a flow-down buffering flange 28 is detachably attached to the inner peripheral surface of the net body 11 by bolts or the like. The flange 28 slows down the flow rate of the cooling liquid, enables longer-time dewatering, and can effectively perform centrifugal dewatering.

FIG. 4 shows a fourth embodiment of the metal powder production apparatus. In this embodiment, the cooling cylinder 1 is arranged with its cylinder axis inclined and formed on the inner peripheral surface thereof. Two jet nozzles 24, 24 are provided via compressed gas supply pipes 27, 27 so that the gas jet 26 intersects the V shape in the space 23 inside the coolant layer 9. The nozzle openings of the jet nozzles 24 and 24 have a slit shape, and the gas jet 26 also has a film shape having a constant width. It has a V shape. Then, the molten metal 25 flows down from the nozzle hole 20 of the crucible 15 into the intersection of the V-shaped gas jet and is separated. According to such a V-shaped gas jet, the dividing effect is excellent, and even if the flowing position of the molten metal 25 slightly shifts, the divided droplets are scattered from the intersection area to a specific area on the inner peripheral surface of the coolant layer 9. Can be injected. Note that a planar gas jet having an inverted R-cone shape may be formed by using a jet nozzle whose nozzle opening is formed by an inverted conical slit, and a molten metal may be supplied to the intersection. Also, a plurality of jet nozzles for ejecting linear gas jets are arranged in an inverted cone shape to form an aggregate of inverted cone-shaped linear gas jets, and molten metal is supplied to the intersection. Is also good.

In the third and fourth embodiments, a liquid drain net 11 is continuously provided at the lower end opening of the cooling cylinder 1, from which the gas forming the gas jet 26 flows out. As shown in FIG. 2, a closing lid 31 provided with a discharge pipe 33 may be attached to the opening. According to such a configuration, by adjusting the flow control valve 34 provided in the middle of the discharge pipe 33, the space 23 inside the coolant layer 9 can be easily filled with the gas having the gas jet 26 formed therein. Can be.

In each of the above embodiments, the cooling cylinder 1 is shown as a cylindrical one. However, the present invention is not limited to this.The inner peripheral surface is formed of a rotationally symmetric surface whose diameter gradually decreases along the moving direction of the coolant. The shape may be a funnel shape, for example, a funnel shape. In the case of a trumpet shape formed by a paraboloid of revolution, a cooling liquid layer having a constant inner diameter can be formed without attaching a layer thickness adjusting flange. In the illustrated example, the cooling cylinder is arranged such that the axis of the cylinder is vertical or oblique. However, the present invention is not limited to this, and the cooling water jetting speed is sufficient. As long as the coolant layer 9 is formed on the peripheral surface of the cylinder by the action of centrifugal force, the direction of the cylinder axis does not matter. In addition, in the illustrated example, the ring thickness adjusting ring 10 has an upper surface formed of a horizontal surface or a tapered surface, but the present invention is not limited to this. It may be formed by. Further, the molten metal 22 in the crucible 15 was ejected from the nozzle hole 20 by applying a pressure medium to pressurize, but the gravity (self-weight) acting on the molten metal 22 itself without applying the pressure medium Thus, the gas may be ejected (outflow) from the nozzle hole 20.

The material of the powder to be manufactured in the present invention is not limited to a low melting point metal such as aluminum or an alloy thereof, and includes a high melting point metal such as titanium, nickel, iron or an alloy thereof, and is not particularly limited.

An overall configuration diagram of an example of a continuous metal powder production facility equipped with the metal powder production apparatus of the first embodiment described in FIG. 1 and configured to consistently carry out production, dewatering, and drying of metal powder from supply of molten metal. Are shown in FIGS. 5 and 6. According to this example, the molten metal pumped from the continuous pouring device 41 passes through the above-described metal powder producing device 42, the continuous dewatering device 43, and the continuous drying device 44, and is turned into product metal powder. It is needless to say that the apparatus of another embodiment can be used as a metal powder production apparatus.

The continuous pouring apparatus 41 includes a main body container 46 formed of a refractory heat insulating material. The container 46 is provided with a molten metal supply port 48 that can be hermetically sealed by a lid 47 and is provided with an inert gas or the like. A pressure medium supply pipe 49 and a discharge pipe 50 for the molten metal 53 in the vessel are provided, and a recess 52 having an induction heating coil 51 is provided at the bottom. The temperature of the molten metal 53 in the vessel 46 is controlled by the coil 51, and the crucible of the metal powder production apparatus 42 is discharged through an exhaust pipe 50 by an inert gas such as argon gas injected from a pressurized medium pipe 49. It is pumped to 15. The discharge pipe 50 is kept warm by an appropriate heat keeping means such as formation of a heat insulating layer and an induction heater.

The metal powder manufactured by the metal powder manufacturing apparatus 42 is drained. It is supplied to the continuous dewatering machine 43 via the powder container 12 together with the residual cooling liquid after the primary dewatering by the netting device 11, and is dewatered by the action of centrifugal force. The continuous dewatering machine 43 includes a rotating drum 55 whose diameter is increased upward, a peripheral wall of an intermediate portion of the drum 55 is formed by a screen plate having a large number of pores, and an inner peripheral surface of the drum 55 holds powder after dehydration. A large number of convex ribs 56 are formed for feeding the sheet to the outside. A cooling liquid collecting cover 57 is provided on the outer peripheral surface side of the rotating drum 55, and the drained cooling liquid is collected in the tank 8 from the bottom thereof. A metal powder collecting cover 58 is provided above the rotating drum 55, and a discharge shot 59 is provided.

The wet metal powder discharged from the discharge shot 59 of the continuous liquid remover 43 is pulled and supplied to the continuous drying device 44. The continuous drying device 44 includes a drying container 62 having a fluidized bed 61 having a large number of pores, a supply device 63 having a rotary feeder for supplying a wet raw material from an upper portion of the container 62, A hot air generator 64 for supplying hot air from a lower part of the container 62; and a cyclone 65 for collecting fine powder from exhaust air discharged from an upper part of the container 62, and an upper part and a lower part of the container 62. A discharge pipe 66 is attached to the side wall.

In the drying vessel 62, a fluidized bed 67 is formed, and the wet metal powder is mixed vigorously with hot air in the fluidized bed 67, heat exchanged, dried quickly, and usually overflowed through the discharge pipe 66. It is taken out.

In practicing the present invention, the continuous pouring device, the continuous dewatering device, and the continuous drying device are not limited to those described above, and any suitable devices available on the market can be used.

Next, specific production examples of metal powder will be described.

Aluminum alloy powder was manufactured using the manufacturing equipment shown in Fig. 7. . The inner diameter D of the cooling cylinder 1 was 100 mm, and the discharge port of the cooling liquid ejection flow path 5 was provided at an intermediate position between the upper end of the cooling cylinder 1 and the upper end of the layer thickness adjusting ring 10. The discharge port diameter of the cooling liquid discharge channel 5 was 11.5 mra, from which cooling water was discharged at a flow rate of 0.3 niVrain. As a result, a coolant layer 9 with an inner diameter d = 55 mm, a length h = 50 mm, and a water film surface velocity of 43 m / sec was formed above the ring thickness adjusting ring 10.

Crucible 15 and 1000. A molten aluminum alloy of C (composition: wt%, A1-12Si-1 Mg-lCu) was produced. Then, 1.0 kgi / cm ² of argon gas is supplied to the crucible 15 to pressurize the molten metal 22 in the crucible 15, and the liquid molten metal 25 having a diameter of 2 mm from the nozzle hole 20 of the crucible 15 is supplied to the cooling liquid layer 9. It erupted into the space 23 inside. The jet angle 01 between the trickle-like molten metal 25 and the horizontal plane was set to 30 °.

A jet 26 was jetted from a jet nozzle 24 having a nozzle hole diameter of 6 mm at a pressure of 5 kgf / ciB ² toward the molten metal 25 in the space 23. Eggplant jetting angle 0 ₂ of the Jiwe' bets 26 and the horizontal plane was set to 45. Also, as shown in FIG. 8, the angle between the jet 26 and the trickle-shaped molten metal 25 was set to be 0 ₈ = 45 ° when measured in a plane A from the molten metal 25 in the turning direction A of the cooling liquid layer in a plan view. .

As a result, an aluminum alloy powder having the particle size distribution shown in FIG. 9A (the relationship between the particle size of a certain powder and the content% by weight of the powder with respect to the total amount of the powder) was obtained. The average particle size of the powder is 291. 8 z ra, bulk density was 0. 90g / cra ^3. Observation of the particle shape of the powder revealed a flat and irregular shape. Therefore, it is estimated that the droplet separated by the jet was re-divided by the cooling liquid layer.

For comparison, aluminum alloy powder was manufactured under the same conditions except that a jet X was sprayed on the molten metal. The result is shown in Fig. 9. B is shown together. The average particle size in this case was 420 urn. The bulk density was 0.70 g / cm ³ . Therefore, it was confirmed that pulverization can be easily achieved by spraying the jet in the examples.

Aluminum alloy powder having the same composition as in Production Example 1 was produced using the production apparatus shown in FIG. The inner diameter of the cooling cylinder 1 was 200 mm, and the cylinder axis was inclined by 25 ° with respect to the vertical direction. The outlet diameter of the coolant discharge channel 5 was 11.5 mm, from which the coolant was jetted at a flow rate of 0.3 m ³ / min. As a result, a cooling liquid layer 9 having an inner diameter of 250 mm, a length of 300 mm, and an average flow velocity of 20 m / sec was formed between the annular lid 2 and the layer thickness adjusting ring 10. Also, adjust the flow control valve 34 so that the coolant is filled in the discharge passage 32.

Crucible 15 and 1000. The molten aluminum alloy of C is melted, and l. Okgf / cra ² argon gas is supplied to the crucible 15 to pressurize the molten metal 22 in the crucible, and a 2 mm-diameter stream is melted from the nozzle hole 2D of the crucible 15. Metal 25 was jetted vertically downward and supplied to the space 23 inside the coolant layer 9.

Argon gas jet 26 was ejected from jet nozzle 24 having a nozzle diameter of 6 mni at a pressure of 10 kgf / cm ² and sprayed toward molten metal 25 in space 23 to pulverize molten metal 25. The angle between the molten metal 25 and the argon gas jet 26 was 30 °.

The average particle size of the obtained powder is 200 m, the bulk density is 1.3 g / cm ⁸ , and the relationship between the particle size and the cooling rate is shown in FIG. The cooling rate was judged from the metal structure of the powder particles. From the figure, metallic powder produced by the present invention is not intended is relatively large 100 to 1000 / zm particle size, cooling speed is ¹⁰⁴ to: a L0 ⁵ in / sec, obtained fine structure You can see that From the figure, it is estimated that the cooling rate in the case of a particle size of 0.1 im is 10 ^{8 or more} / sec. Then, by measurement of amount of gas contained in the _{powder, H 2: 12pp in, 0} 2: was 500 ppm. For comparison, the flow control valve 34 was fully opened to prevent the discharge pipe 33 from being blocked by the cooling water, and the aluminum alloy powder was manufactured under the same conditions except for the above. Gas content of the obtained _{_{powder, H 2: 20ppm, 0 2}} : was 820 ppm. As a result, it can be seen that the gas content of the example is significantly reduced as compared with the comparative example.

An iron alloy powder was produced under the same production conditions as in Production Example 2. However, the composition of the iron alloy was Fe-1.3C-4Cr-3.5Mo-10W-13.5V-10Co in wt%, and the melting temperature was 1600 ° C.

The average particle diameter of the obtained powder was 250 tz ni, was measured the amount of gas contained in the _{powder, H 2: 9 ppra, 0} 2: 580ppra, N 2: was 72 Oppra. In addition, when the average flow velocity of the cooling liquid layer was 5 in / sec, others produced iron alloy powder of the composition in said Article matter, gas _{_{content, H 2: 15ppm, 0 2}} : 1200 ppm, N 2 : 740 ppm. From this, it can be seen that as the flow velocity of the cooling liquid layer is increased, the cooling liquid vapor generated around the droplet is quickly separated from the droplet, and a better pollution prevention effect is obtained.

[Industrial applicability]

The present invention relates to powder metallurgy, raw material powder for hot isostatic pressing, hot forging, hot extrusion, etc., composite powder for synthetic resin, rubber, metal, etc., electromagnetic clutch

• Used for the production of metal powder used for magnetic powder for brakes, etc.

Claims

The scope of the claims

(1) A cooling liquid layer is formed by jetting and supplying the cooling liquid along the inner peripheral surface of the cooling cylinder, and moving while rotating along the inner peripheral surface of the cylinder toward the cooling liquid discharge end of the cylindrical body. ;

Supplying molten metal to a space inside the coolant layer;

The molten metal is blown with a gas jet directed to the cooling liquid layer to divide the molten metal, and the separated molten metal is supplied to the cooling liquid layer;

A method for producing metal powder, comprising discharging a cooling liquid containing metal powder solidified in a cooling liquid layer from a cooling liquid discharge end of a cylindrical body to the outside.

(2) The cooling liquid containing the metal powder solidified in the cooling liquid layer is discharged from the discharge pipe provided on the closing lid attached to the cooling liquid discharge end of the cylinder to the outside while passing through the pipe. The method for producing a metal powder according to claim 1.

(3) The method for producing a metal powder according to claim 1 or 2, wherein water is used as a cooling liquid and a gas jet is formed with an inert gas.

(4) The method for producing metal powder according to claim 1 or 2, wherein the cooling body has a cylindrical shape.

(5) The method for producing a metal powder according to claim 1 or 2, wherein the molten metal is supplied by gravity.

(6) The method for producing a metal powder according to claim 1, wherein the metal powder discharged together with the cooling liquid is continuously drained, and then continuously dried.

(7) a cooling cylinder provided with a coolant ejection channel for ejecting and supplying coolant along the inner peripheral surface;

The cooling liquid ejected from the cooling liquid ejection flow path is formed on the inner peripheral surface of the cylindrical body. Molten metal supply means for supplying molten metal to a space inside the coolant layer formed to move to the coolant discharge end side of the cylinder while turning along;

A gas jet ejection means for jetting a gas jet for cutting the molten metal and supplying the split molten metal to a cooling liquid layer;

A cooling liquid supply means for supplying a cooling liquid to the cooling liquid ejection flow path.

(8) The cooling liquid discharge end of the cooling cylinder is provided with a closing lid, and the closing lid is provided with a discharge pipe for discharging the cooling liquid in a state where the pipe is filled with the cooling liquid. The metal powder production equipment described in Paragraph 7.

(9) The metal powder production apparatus according to claim 7 or 8, wherein the cooling cylinder has a cylindrical shape.

(10) The metal powder production apparatus according to claim 9, wherein a ring for adjusting the thickness of the cooling liquid layer is mounted on an inner peripheral surface of the cooling cylinder.

(11) The metal powder production apparatus according to claim 10, wherein a plurality of layer thickness adjusting rings are mounted.