JP2719074B2 - Method and apparatus for producing metal powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing metal powder by supplying molten metal into a swirling cooling liquid layer.

[0002]

2. Description of the Related Art Since a rapidly solidified metal powder has fine crystal grains and can contain alloy elements in a supersaturated state, an extruded material or a sintered material formed by using the same is not provided in a melted material. It has excellent material properties and is attracting attention as a material for machine parts and the like. As a method for producing the above-mentioned 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 molten metal is jetted into the cooling liquid layer.
This is a method of obtaining a rapidly solidified metal powder by dividing this by a rotating cooling liquid layer.

On the other hand, US Pat. Nos. 4,787,935 and 4,869,469
No. 2, a method for producing metal powder for cooling and solidifying by supplying a atomized spherical droplet to a swirling flow of a cooling gas flowing down while rotating in a cooling cylinder after gas atomizing a molten metal flow and An apparatus is disclosed.

[0004]

According to the rotary drum method, a so-called batch operation is performed, and there is a problem that productivity is poor. Further, 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 U.S. Patent, a fine powder having a particle size of 0.1 μm
It can be manufactured continuously to a coarse powder of the order of magnitude. However, in this manufacturing method, there is a problem that the droplets at the center of the spiral flow of the cooling gas are hardly swirled and the cooling rate is reduced, so that the quality of the manufactured powder tends to vary. Further, in order to form a spiral flow of the cooling gas suitable for cooling the droplets in the cooling cylinder, the cooling cylinder must be considerably large. There is a problem that it is difficult to implement.

The present invention has been made in view of such a problem, and a method for producing a metal powder and a method for producing a metal powder capable of rapidly solidifying at a high cooling rate with less variation in cooling rate and easily obtaining fine powder. It is an object of the present invention to provide a suitable manufacturing apparatus for performing the above.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for producing a metal powder, comprising: supplying a molten metal to a cooling liquid layer formed in a cooling cylinder, cooling and solidifying the molten metal to produce a metal powder; The coolant is spouted and supplied to the inner peripheral surface of the cooling cylinder so as to form a coolant layer that moves in the axial direction to the coolant discharge end side of the cylinder while rotating along the inner peripheral surface of the cylinder. A cooling liquid ejection flow path, and a layer thickness adjusting means for forming the cooling liquid layer to a required thickness, a molten metal is supplied to an inner space of the cooling liquid layer, and a cooling liquid layer is supplied to the molten metal. The molten metal that has been separated is supplied to the cooling liquid layer to be cooled and solidified by spraying a gas jet directed toward the cooling liquid layer, and the cooling liquid containing the metal powder solidified in the cooling liquid layer is discharged from the cooling liquid discharge end of the cylindrical body. It is characterized by discharging to the outside.

When the coolant containing the metal powder is discharged to the outside, a closing lid to which a discharge pipe is connected is provided at the coolant discharge end of the cylindrical body, and the metal powder solidified in the coolant layer is removed. It is preferable that the coolant containing the liquid is discharged from the discharge pipe to the outside while filling the pipe. Further, in the manufacturing apparatus of the present invention, in the metal powder manufacturing apparatus provided with a cooling cylinder in which a cooling liquid layer is formed along the inner peripheral surface, the cooling liquid body is swung along the inner peripheral surface of the cylinder. A cooling fluid ejection flow path for ejecting coolant to the inner peripheral surface to form a cooling fluid layer moving in the axial direction on the cooling fluid discharge end side of the cylindrical body, and forming the cooling fluid layer to a required thickness And a molten metal supply means for supplying molten metal to the inner space of the cooling liquid layer, and the molten metal separated into the cooling liquid layer while dividing the molten metal. Gas jet ejection means for ejecting a gas jet to be supplied.

Preferably, the cooling cylinder is provided with a closing lid at a cooling liquid discharge end, and a discharge pipe for discharging the cooling liquid in a state where the lid is filled with the cooling liquid.

[0009]

The cooling liquid ejected and supplied from the cooling liquid ejection passage along the inner peripheral surface of the cooling cylinder turns toward the cooling liquid discharge end opening of the cylinder while rotating along the inner peripheral surface of the cylinder. To move in the axial direction. At this time, due to the centrifugal force at the time of turning and the action of the layer thickness adjusting means, a coolant layer having a required thickness and a substantially constant inner diameter is formed on the inner peripheral surface of the cylinder. Since this cooling liquid layer is always formed by a newly supplied cooling liquid, a constant temperature is easily maintained. Further, since the cooling medium is a liquid, the cooling medium is superior in the cooling ability as compared with the gas. Such a cooling liquid 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.

[0010] The molten metal supplied from the molten metal supply means to the space inside the coolant layer is blown by a gas jet ejected from the gas jet ejection means toward the coolant layer, and is divided. . The divided molten metal (droplets) scatters toward the coolant layer and is injected and supplied into the coolant layer. The droplets injected into the cooling liquid layer generate vapor of the cooling liquid around the droplets, and the vapors quickly escape from around the droplets. That is, the droplets injected into the swirling cooling liquid layer and moving in the circumferential direction further move radially outward in the cooling liquid layer having a required thickness by the action of the centrifugal force. This results in a difference in the direction of movement between the droplet and the coolant,
The vapor film generated on the surface of the droplet is promptly peeled off. As a result, the outer peripheral surface of the droplet is always in contact with the cooling liquid, and the droplet is rapidly solidified at a high cooling rate.

Further, by controlling the flow rate and flow rate of the gas jet, the size of the divided droplets can be easily adjusted, so that the desired rapidly solidified 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 condition of the droplets is constant, and the quality of the powder is also stable. Since the cooling liquid layer is formed continuously, the continuous production of powders becomes possible by continuously supplying the molten metal, continuously blowing the gas jet to cut and supplying the molten metal to the cooling liquid layer. Then, 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, and a uniform metal powder is continuously produced.

When discharging the cooling liquid containing the metal powder,
It is preferable that a cover for closing the cooling liquid is provided at an opening of a cooling liquid discharge end of the cylindrical body, and the cooling liquid is discharged to the outside from a discharge pipe provided in the cover for closing while filling the inside of the pipe. According to this method, the gas forming the gas jet can be easily filled in the space inside the cooling liquid layer. 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.

[0013]

FIG. 1 shows an apparatus for producing metal powder according to an embodiment of the present invention. A crucible 15 which is a molten metal supply means for supplying the molten metal 25 downflow,
A pump 7 serving as a means for supplying a cooling liquid to the cylindrical body 1, a gas jetting a gas jet 26 for dividing the flowing down stream of molten metal 25 into droplets and supplying the molten metal 25 to the cooling liquid layer 9. A jet nozzle 24 serving as a jet ejection means.

The cylindrical body 1 has a cylindrical shape, the axial center of the cylindrical body is installed in a vertical direction, and an annular lid 2 is provided at the upper end opening.
An opening 3 for supplying molten metal to the inside of the cooling cylinder 1 is formed in the center of the lid 2. Further, a cooling liquid ejection flow path 5 is provided above the cooling cylinder 1.
A plurality of cooling liquid ejection pipes 4 are formed at equal intervals in the circumferential direction, and an outlet (discharge port) of the flow path 5 can eject and supply the cooling liquid from the tangential direction along the inner peripheral surface of the cooling cylinder 1. It is open to. The center line of the opening of the flow path 5 is set obliquely downward by about 0 to 20 ° with respect to a plane orthogonal to the cylinder axis. The cooling liquid jet pipe 4 is connected to a pump 7
The cooling liquid in the tank 8 is sucked up by the pump 7 and jetted and supplied from the cooling liquid jetting flow path 5 of the jetting pipe 4 to the inner peripheral surface side of the cooling cylinder 1. As a result, a cooling liquid layer 9 is formed on the inner peripheral surface of the cylindrical body 1 and flows down while rotating along the inner peripheral surface. In tank 8,
A replenishing coolant supply pipe (not shown) is provided, and a cooler may be appropriately provided in the tank 8 or in the middle of the coolant circulation channel. Water is generally used as the cooling liquid. This is because it has excellent cooling performance and low cost. In addition to water, a liquid used for quenching a heated metal 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 easily available.

A layer thickness adjusting ring (layer thickness adjusting means) 10 for adjusting the layer thickness of the cooling liquid layer 9 is detachably and detachably attached to the lower portion of the inner peripheral surface of the cooling cylinder 1 by bolts. The flow rate of the cooling liquid is suppressed by the ring 10, so that the cooling liquid layer 9 having a substantially constant inner diameter can be easily formed with a small flow rate. A cylindrical liquid drain net 11 is connected to a lower end opening of the cylindrical body 1 which is a cooling liquid discharge end, and a funnel-shaped powder collecting container 12 is attached below the net 11. The net 11
A coolant collecting cover 13 is provided around the mesh 11 so as to cover the net 11, and a drain port 14 is formed at the bottom of the collecting cover 13. The drain port 14 is connected to the tank 8 via a pipe. It is connected.

The crucible 15 disposed above the cooling cylinder 1 is made of a refractory material such as graphite or silicon nitride, and closes the bottomed cylindrical crucible body 16 and the upper end opening of the crucible body 16. And a lid 17. An induction coil 18 for heating is provided on the outer periphery of the crucible body 16, and a bottom portion 19 of the crucible body 16 is provided.
, A nozzle hole 20 is formed in the vertical direction, and the nozzle hole 20 faces the opening 3 of the annular lid 2. Further, the lid 17 of the crucible 15, Ar and the injection hole 21 for injecting a pressure medium and pumping molten metal inert gas such as N ₂ is formed, inert gases and the like from the injection hole 21 Is pressurized, the molten metal 22 in the crucible 15 is ejected from the nozzle hole 20 to the space 23 inside the cooling liquid layer 9 through the opening 3.

A jet nozzle 24 for jetting compressed gas such as air or inert gas used in a normal gas atomizing method is disposed in a space 23 inside the cooling liquid layer 9. The nozzle 24 is attached to the distal end 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 provided with a cooling liquid layer 9 and a crucible.
It is directed to the molten metal 25 in the form of a rivulet ejected from the 15 nozzle holes 20.

Although the outlet of the cooling liquid ejection flow path 5 is open in the upper side of the cooling cylinder 1 in the figure, if the distance between the outlet and the layer thickness adjusting ring 10 is long, the cooling liquid flows down. Since the layer thickness of the cooling liquid layer 9 tends to be concave at the center due to the increase in the speed, 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. An opening is preferably provided between the position and the upper surface of the ring 10. 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 having a constant thickness almost the same as that below is formed.

In the above configuration, in order to produce the metal powder, first, the pump 7 is operated to form the cooling liquid layer 9 on the inner peripheral surface of the cylinder 1, and then the molten metal 22 in the crucible 15 is discharged. It is ejected downward from the nozzle hole 20. At this time, the jet nozzle
Gas jet 26 is spouted at high speed from 24. Crucible
Jet nozzle on the molten metal 25 in the form of a trickle ejected from 15
The gas jet 26 jetted from 24 is blown, the molten metal 25 is divided, and the divided droplets are scattered toward the cooling liquid layer 9. The scattered droplets are injected into the cooling liquid layer 9 flowing down while turning, and are 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 cooling liquid 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 cooling liquid layer 9 is shortened, the droplet separated by the gas jet 26 is injected into the cooling liquid layer 9 before forming a solidified shell on its surface, and is again separated by the cooling liquid layer 9. Therefore, a fine amorphous powder can be obtained. On the other hand, if the distance is sufficient, a solidified shell is formed on the surface of the droplet,
Even if it is 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 over the layer thickness adjusting ring 10 while rotating together with the cooling liquid, and enters the draining net 11 from the lower end opening of the cooling cylinder 1. . Here, the cooling liquid is scattered 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 primary-dewatered metal powder enters the powder recovery container 12, is discharged therefrom, is de-liquidized by a de-watering device such as a centrifuge, and is dried by a drying device.
Further, the coolant scattered from the net 11 is returned to the tank 8 via the recovery cover 13 to be circulated.

FIG. 2 shows another embodiment of the apparatus for producing metal powder, and the same members as those of the apparatus of the above embodiment are designated by the same reference numerals. In this embodiment, the cooling cylinder 1 is arranged with the cylinder axis inclined. The coolant jet channel 5 is opened directly in the thick cooling cylinder 1, and the inlet of the coolant jet channel 5 opened on the outer peripheral surface of the cooling cylinder 1 is connected to the pump 7 by piping. . In addition, a funnel-shaped closing lid 31 for closing the opening is attached to the lower end opening of the cooling cylinder 1, and a cooling liquid discharge pipe 33 is provided at the bottom thereof, and the inside thereof is provided. A cooling liquid discharge passage 32 is provided. A layer thickness adjusting ring 10 having an upper surface formed as a tapered surface is attached to a lower inner peripheral surface of the cooling cylinder 1 by a bolt. The discharge pipe 33 has an end opening (exit).
Is arranged at a position above the tank 8, and a flow regulating valve 34 is provided in the middle of the pipe. The tank 8
A net basket 35 is detachably attached to the upper opening of.

In this embodiment, by appropriately adjusting the opening and closing of the flow control valve 34, the coolant can be discharged in a state of being filled in the discharge passage 32. In this case, the gas can be prevented from flowing out from the coolant 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, it is possible to effectively prevent the divided droplets from being oxidized.

FIG. 3 shows a third embodiment of the apparatus for producing metal powder. In this embodiment, the outlet of the cooling liquid ejection flow path 5 is provided in a plurality of stages (2 Step) is open. The number and intervals of the cooling liquid ejection flow paths 5 in the cylinder axis direction vary depending on the inner diameter of the cylinder, the discharge amount of the cooling liquid, the ejection pressure, the set distance of the lower layer thickness adjusting ring 10, and the like. An appropriate number of stages may be provided at substantially equal intervals so that the cooling liquid layer 9 is obtained. In this embodiment, since a plurality of cooling liquid jet channels 5 are provided above the layer thickness adjusting ring 10, the layer thickness of the cooling liquid layer 9 due to an increase in the flow rate of the cooling liquid above the ring 10 is increased. The cooling liquid layer 9 having a substantially constant inner diameter and a constant swirling flow rate can be easily formed in a long range on the inner peripheral surface of the cylindrical body 1, and the cooling region can be provided in a long range. it can. As shown in the drawing, 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 layer thickness and the flow velocity of the cooling liquid layer 9 can be further stabilized. However, even if the cooling liquid ejection flow path 5 is formed as one stage and only a plurality of layer thickness adjusting rings are provided, there is an effect of preventing a decrease in the layer thickness of the cooling liquid layer 9.

In the third embodiment shown in FIG. 3, a downflow buffering flange 28 is detachably attached to the inner peripheral surface of the net body 11 by bolts or the like. By the flange 28, the flow speed of the cooling liquid is slowed down, the liquid can be removed for a longer time, and the centrifugal liquid removal can be effectively performed by effectively utilizing the flowing energy as the rotational energy in the circumferential direction. it can.

FIG. 4 shows a fourth embodiment of the metal powder production apparatus. In this embodiment, the cooling cylinder 1 is arranged with the cylinder axis inclined, and the cooling cylinder 1 has an inner peripheral surface. Two jet nozzles 24, 24 are provided via compressed gas supply pipes 27, 27 so that the gas jets 26 intersect in a V-shape in the space 23 inside the formed cooling liquid layer 9. The nozzle openings of the jet nozzles 24, 24 are slit-shaped, and the gas jet 26 is also in the form of a film having a constant width, and the cross section in the crossing state is V-shaped as shown in the figure. Then, the molten metal 25 is placed in the crucible at the intersection of the V-shaped gas jet.
It flows down from the 15 nozzle holes 20 and is separated. Such V
According to the shaped gas jet, the divided droplet is excellent in the dividing effect, and even if the flowing position of the molten metal 25 is slightly shifted, the divided droplet is scattered from the intersection area and injected into a specific range of the inner peripheral surface of the cooling liquid layer 9. be able to. It should be noted that an inverse conical planar gas jet may be formed using a jet nozzle whose nozzle opening is formed by an inverted conical slit, and molten metal may be supplied to the intersection. Alternatively, a plurality of jet nozzles for ejecting a linear gas jet may be arranged in an inverted conical shape, an aggregate of the inverted conical linear gas jets may be formed, and molten metal may be supplied to the intersection. .

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

In each of the embodiments described above, the cooling cylinder 1 has a cylindrical shape, and an example in which a layer thickness adjusting ring 10 is provided on the inner peripheral surface thereof as a layer thickness adjusting means has been described. However, the present invention is not limited to this, and the inner peripheral surface may be formed as a rotationally symmetric surface whose diameter gradually decreases along the moving direction of the coolant, for example, a funnel shape. can do. That is, in the case of a trumpet shape formed by a paraboloid of revolution, an increase in the flowing speed of the cooling liquid layer flowing down while turning is suppressed by the above-described shape, and therefore, even if the layer for thickness adjustment is not attached, the required thickness can be reduced. A cooling liquid layer having a constant inner diameter can be formed. Further, 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. As long as the cooling liquid layer 9 is formed on the peripheral surface of the body by the action of the centrifugal force, the direction of the cylinder axis does not matter.

In the illustrated example, the layer thickness adjusting ring 10 has an upper surface formed of a horizontal surface or a tapered surface. However, the present invention is not limited to this. It may be formed by a linear curved surface. Further, the molten metal 22 in the crucible 15 was ejected from the nozzle hole 20 by applying a pressure medium and applying pressure, but without applying a pressure medium, due to gravity (self-weight) acting on the molten metal 22 itself, It may be ejected (outflow) from the nozzle hole 20.

The material of the powder to be produced in the present invention is not limited to a low melting point metal such as aluminum or its alloy, but also includes a high melting point metal such as titanium, nickel, iron or their alloys. Not done. Further, the metal powder produced according to the present invention may be used as a raw material powder for powder metallurgy, hot isostatic pressing, hot forging, hot extrusion, etc., a composite powder for synthetic resin, rubber, metal, etc., an electromagnetic clutch. -Used for magnetic powder for brakes, etc.

The entirety of an example of a continuous metal powder production facility equipped with the metal powder production apparatus of the first embodiment described with reference to FIG. Configuration diagrams are shown in FIG. 5 and FIG. 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 converted into product metal powder. It is needless to say that another embodiment of the metal powder manufacturing apparatus can be used.

The continuous pouring apparatus 41 has a main body container 46 formed of a fire-resistant heat insulating material. The container 46 is provided with a molten metal supply port 48 which can be sealed by a lid 47 and is inactive. Pressure medium supply pipe 49 for gas etc., discharge pipe 50 for molten metal 53 in vessel
And a concave portion 52 having an induction heating coil 51 is provided at the bottom. By the coil 51, the container
The temperature of the molten metal 53 in the 46 is controlled, and the molten metal 53 is discharged by an inert gas such as argon gas injected from a pressure medium supply pipe 49.
It is fed to the crucible 15 of the metal powder production device 42 via 50. The discharge pipe 50 is kept warm by a suitable heat keeping means such as formation of a heat insulating layer and an induction heater.

The metal powder produced by the metal powder producing apparatus 42 is supplied to the continuous dewatering machine 43 via the powder recovery container 12 together with the residual cooling liquid after the primary dewatering by the drainage net 11. , Liquid is removed by the action of centrifugal force. The continuous dewatering machine 43 includes a rotating drum 55 having a diameter that is increased upward.
The peripheral wall of the intermediate portion of 55 is formed of a screen plate having a large number of pores, and a large number of convex ribs 56 for sending out the dewatered powder upward are formed on the inner peripheral surface. Rotating drum
A coolant collecting cover 57 is provided on the outer peripheral surface side of 55, and the drained coolant 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 chute 59 is provided.

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

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 and dried promptly, and the discharge pipe 66 is usually overflowed. Taken out to the outside. still,
In carrying out the present invention, the continuous pouring device, the continuous dewatering device, and the continuous drying device are not limited to those described above, and appropriate devices supplied to the market can be used.

Next, specific examples of the production of metal powder will be described. <Production Example 1> An aluminum alloy powder was produced using the production apparatus shown in FIG. 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 ejection flow path 5 was 11.5 mm, from which cooling water was ejected at a flow rate of 0.3 m ³ / min. As a result, the inner diameter d = 55 mm, the length h = 50 mm, and the water film surface velocity above the layer thickness adjusting ring 10.
A cooling liquid layer 9 of 43 m / sec was formed.

In a crucible 15, a molten aluminum alloy (Al-12Si-1Mg-1Cu in composition: wt%) at 1000 ° C. was melted. And
1.0 kgf / cm ² of argon gas is supplied to the crucible 15 to pressurize the molten metal 22 in the crucible 15, and a small stream of molten metal 25 having a diameter of 2 mm is supplied from the nozzle hole 20 of the crucible 15 to the space inside the cooling liquid layer 9. It erupted into part 23. Eggplant ejection angle theta ₁ between trickle-shaped molten metal 25 and the horizontal plane was 30 °.

An air jet 26 is directed from a jet nozzle 24 having a nozzle hole diameter of 6 mm toward the molten metal 25 in the space 23.
It was jetted at 5 kgf / cm ² and sprayed. Eggplant ejection angle theta ₂ between the jet 26 and the horizontal plane was 45 °. Further, as shown in FIG. 8, the angle between the jet 26 and the trickle-like molten metal 25 was set to θ ₃ = 45 ° when measured in a plane A from the molten metal 25 in the swirling direction A of the cooling liquid layer.

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 this powder was 291.8 μm, and the bulk density was 0.90 g / cm ³ . Further, when the particle shape of the powder was observed, it was found to be a flat and irregular shape. Therefore, it is estimated that the droplet separated by the air jet is re-divided by the cooling liquid layer.

For comparison, an aluminum alloy powder was produced under the same conditions except that an air jet was blown toward the molten metal. The results are also shown in FIG. 9B. In this case, the average particle size was 420 μm, and the bulk density was 0.70 g / cm ³ . Therefore, it was confirmed that pulverization can be easily achieved by blowing the air jet in the examples.

<Production Example 2> An 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 axis of the cylinder was inclined by 25 ° with respect to the vertical direction. The discharge port diameter of the coolant ejection flow path 5 is 11.5 mm,
From this, cooling water was jetted at a flow rate of 0.3 m ³ / min. As a result, an inner diameter of 25 mm is provided between the annular lid 2 and the layer thickness adjusting ring 10.
A cooling liquid layer 9 having a thickness of 0 mm, a length of 300 mm and an average flow velocity of 20 m / sec was formed. Further, the flow rate adjusting valve 34 was adjusted so that the discharge liquid 32 was filled with the cooling liquid.

A molten aluminum alloy at 1000 ° C. was melted in the crucible 15, and 1.0 kgf / cm ² of argon gas was supplied to the crucible 15 to pressurize the molten metal 22 in the crucible 15, and from the nozzle hole 20 of the crucible 15. A trickle-shaped molten metal 25 having a diameter of 2 mm was jetted vertically downward and supplied to the space 23 inside the cooling liquid layer 9. An argon gas jet 26 was injected from the jet nozzle 24 having a nozzle hole diameter of 6 mm toward the molten metal 25 in the space 23 at a pressure of 10 kgf / cm ^2.
And the molten metal 25 was powdered. The angle between the molten metal 25 and the argon gas jet 26 was 30 °.

The average particle size of the obtained powder was 200 μm, the bulk density was 1.3 g / cm ³ , and the relationship between the particle size and the cooling rate was shown in FIG.
Shown in The cooling rate was determined based on the metal structure of the powder particles. From the figure, it can be seen that the metal powder manufactured according to the present invention has a cooling rate of 10 ⁴ to 10 ⁵ ° C / sec and a fine structure can be obtained even if the metal powder has a relatively large particle size of 100 to 1000 μm. From the figure, it is estimated that the cooling rate when the particle size is 0.1 μm is 10 ⁸ ° C / sec or more.

Next, when the amount of gas contained in the powder was measured, it was H ₂ : 12 ppm and O ₂ : 500 ppm. For comparison,
The aluminum alloy powder was manufactured under the same conditions except that the flow control valve 34 was fully opened so that the cooling liquid discharge pipe 33 was not closed by the cooling water, and the other conditions were the same. The gas content of the resulting powder is
H ₂ : 20 ppm and O ₂ : 820 ppm. Thus, it can be seen that the gas content of the example is significantly reduced as compared with the comparative example.

<Production Example 3> An iron alloy powder was produced under the same production conditions as in Production Example 2. However, the composition of the iron alloy is Fe-1.3C-4Cr-3.5Mo-
10W-3.5V-10Co, and the melting temperature was 1600 ° C. The average particle size of the obtained powder was 250 μm, and the amount of gas contained in the powder was measured.H ₂ : 9 ppm, O ₂ : 580 ppm, N ₂ : 7
It was 20 ppm. In addition, when the average flow velocity of the cooling liquid layer is 5 m / sec, the other is that manufactured the iron alloy powder of the composition under the same conditions, the gas _{content, H 2: 15ppm, O 2} : 1200ppm, N 2: at 740ppm there were. Thus, as the flow rate of the cooling liquid layer increases,
It can be seen that the cooling liquid vapor generated around the droplet quickly separates from the droplet, and a good contamination preventing action can be obtained.

[0045]

As described above, according to the present invention, a cooling liquid layer which moves while rotating along the inner peripheral surface of the cooling cylinder is formed with a required thickness. Since the temperature can be easily maintained constant and the cooling capacity is excellent, the cooling cylinder and thus the manufacturing equipment can be made more compact and the equipment cost can be reduced. By supplying the molten metal, that is, droplets, which have been previously divided by the gas jet to the cooling liquid layer, the cooling liquid can be cooled and solidified at a high cooling rate, and rapidly solidified powder with little variation can be easily obtained.

Further, by discharging the cooling liquid containing the powdered metal powder so as to close the cooling discharge pipe at the bottom of the cooling cylinder, the gas jet is discharged into the space inside the cooling liquid layer. Since the gas can be filled, the oxidation of the droplet can be effectively prevented by using the inert gas, and a high-quality metal powder can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a metal powder manufacturing apparatus according to an embodiment.

FIG. 2 is a sectional view of a main part of the apparatus according to another embodiment.

FIG. 3 is a sectional view of a main part of the device according to a third embodiment.

FIG. 4 is a sectional view of a main part of the same apparatus according to a fourth embodiment.

FIG. 5 is an explanatory sectional view of a continuous pouring apparatus.

FIG. 6 is an overall layout view of a 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 positional relationship diagram between a trickle-shaped molten metal and a gas jet in a production example.

FIG. 9 is a graph showing the particle size distribution of metal powders produced by Production Examples and Production Comparative Examples.

FIG. 10 is a graph showing the relationship between the particle size of metal powder produced according to the production example of the present invention and the cooling rate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling cylinder 4 Coolant ejection pipe 5 Coolant ejection flow path 7 Pump 9 Coolant layer 10 Layer thickness adjustment ring (layer thickness adjustment means) 15 Crucible (molten metal supply means) 23 Space 24 Jet nozzle (gas (Jet jetting means) 25 Molten metal 26 Gas jet 31 Closure lid 33 Coolant discharge pipe

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Shoichi Yoshino, Inventor 7-21, Minamienkajima, Taisho-ku, Osaka City, Osaka Prefecture Inside Kubota Enkajima Plant (72) Inventor Genuine Yoshino, Taisho-ku, Osaka-shi, Osaka No. 7-22, Enkajima Kubota Corporation Onkajima Plant (72) Inventor Toshiyuki Aoki 7-1-222 Minamienkajima, Taisho-ku, Osaka City, Osaka Prefecture Inside Kubota Enkajima Plant (56) References Special JP-A-61-41707 (JP, A) JP-A-49-98758 (JP, A) JP-B-61-39368 (JP, B2)

Claims (4)

(57) [Claims] 1. A soluble in the cooling liquid layer formed on the cooling cylinder body
Metals that supply molten metal and cool and solidify to produce metal powder
In powder production method, the cooling tubes, while swirling along the tube body circumference
Coolant jet that supplies coolant to the inner peripheral surface to form a coolant layer that moves axially toward the coolant discharge end of the cylinder
Path and layer thickness adjusting means for forming the cooling liquid layer to a required thickness
The door is provided to supply molten metal to the inner space of the cooling liquid layer, and supplying the divided molten metal with dividing by blowing gas jets directed against the cooling liquid layer on the molten metal to the cooling liquid layer and by cooling and solidifying, the metal powder production method characterized by discharging the cooling liquid containing a metal powder solidified in the cooling liquid layer from the coolant discharge end of the tubular body to the outside. 2. A discharge pipe is connected to a cooling liquid discharge end of the cylindrical body.
It is a closed lid provided with metal powder production process according to claim 1, wherein the cooling liquid, characterized in that discharged to the outside while satisfying the tube from the discharge tube containing a metal powder solidified in the cooling liquid layer. 3. A cooling liquid layer in which a cooling liquid layer is formed along an inner peripheral surface.
In the metal powder production apparatus comprising a却用cylindrical body, in the cooling tubes, form the cooling liquid layer moves in the axial direction to the cooling liquid discharge end of the tubular body while swirling along the tube body circumference
Coolant ejection flow path for ejecting and supplying coolant to the inner peripheral surface to form
And a layer thickness adjusting means for forming the cooling liquid layer to a required thickness.
While are provided, the gas jets to supply the molten metal feed means for supplying molten metal to the inner space of the cooling liquid layer, the divided molten metal while cutting the molten metal to the cooling liquid layer metal powder production apparatus characterized by comprising a gas jetting means for jetting. 4. A closed lid is provided in the cooling liquid discharge end of the cooling tubes, that discharge pipe for the said closed lid for discharging it in a state filled with cooling liquid is provided Features and
The metal powder manufacturing apparatus according to claim 3, wherein