JP3136261B2 - 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 to produce metal powder.

[0002]

2. Description of the Related Art A rapidly solidified metal powder has fine crystal grains and can contain alloying elements in a supersaturated state. For example, an extruded material formed by a rapidly solidified powder such as aluminum or an alloy thereof is provided in a molten material. It has excellent material properties that do not cause any problems, and is attracting attention as a material for machine parts and the like.

As a preferred method of producing the rapidly solidified metal powder, as disclosed in Japanese Patent Application Laid-Open No. Hei 6-322417, the cooling liquid is caused to flow down while swirling on the inner peripheral surface of the cooling cylinder. There is a swirling water flow method in which a layer is formed, a jet of molten metal is supplied to the cooling liquid layer from a molten metal supply container, divided, cooled and solidified with the cooling liquid, and separated from the cooling liquid to obtain metal powder.

[0004] The above-mentioned metal powder solidified by cooling is removed by separating a cooling liquid swirling down by a cylindrical drainage net having substantially the same diameter provided at the lower end of the cylindrical body, and removing the metal remaining in the drainage net. The powder is collected.

[0005]

According to the above-mentioned swirling water flow method, it is possible to efficiently produce rapidly solidified powder with simple equipment. However, the cooling liquid is supplied to the drainage net at the lower end of the cylindrical body. Cooling liquid spraying ability to flow down while rotating is required, and the load of the liquid removal process is large, and metal powder with a low cooling rate that falls without entering the cooling liquid layer is mixed with normal metal powder Therefore, its removal is difficult.

According to the present invention, the load of the liquid removing step can be reduced by centrifuging the metal powder in the cooling liquid layer upstream of the position where the cooling liquid is discharged, and the metal powder having a low cooling rate is separated and removed. It is another object of the present invention to provide a metal powder manufacturing method and an apparatus therefor that can be simplified.

[0007]

A concrete means for solving the problems in the method of the present invention is to form a cooling liquid layer 3 by causing a cooling liquid to flow down while rotating on the inner peripheral surface of a cooling cylinder 2,
In the metal powder production method of supplying a molten metal from the molten metal supply means 4 to the cooling liquid layer 3 to separate and cool and solidify the molten metal to obtain a metal powder, in the metal powder manufacturing method, on the upstream side of the position where the cooling liquid of the cylindrical body 2 is discharged, The metal powder in the cooling liquid layer 3 is centrifugally forced into the cylinder 2
It is to discharge in the radial direction.

As a result, the load of the dewatering step is reduced,
The metal powder having a slow cooling rate is discharged together with the cooling liquid. The concrete means for solving the problem in the device of the present invention includes: a cooling cylinder 2 provided with a coolant ejection pipe 6 for ejecting and supplying coolant from a tangential direction along an inner peripheral surface; In a metal powder manufacturing apparatus comprising: a molten metal supply means 4 for supplying molten metal to a cooling liquid layer 3 formed on the inner peripheral surface of the cylindrical body 2 by the cooling liquid jetted from the pipe 6. An outlet 8 for centrifugally separating metal powder from the cooling liquid layer 3 is formed on the peripheral wall of the cylindrical body 2 on the upstream side of the outlet 9 for discharging the cooling liquid formed at the bottom.

As a result, the metal powder is collected before reaching the discharge port 9, the load of the liquid removing step is reduced, the metal powder having a slow cooling rate is discharged and removed together with the cooling liquid, and the apparatus can be reduced in size and simplified. Will be possible.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. In the first embodiment shown in FIG. 1, the metal powder manufacturing apparatus 1A is roughly divided into a cooling cylinder 2, a molten metal supply unit 4, a cooling liquid supply unit 12, a decompression unit 10, and the like.

The cooling cylinder 2 is formed in a bottomed cylindrical shape having an opening at the top, and the upper opening is closed by a lid 17 having an opening 13 at the center. The axis of the cylindrical body 2 is inclined at a required angle, for example, about 20 ° with respect to the perpendicular, and a plurality of coolant jet pipes 6 are formed in the vicinity of the upper part of the peripheral wall 2a at equal intervals in the circumferential direction. Jet port 1 of jet pipe 6
The opening 4 is open so that the coolant can be jetted and supplied from the tangential direction along the inner peripheral surface of the cylindrical body 2.

The coolant jet pipe 6 is connected to a coolant tank 16 and the like via a pump 15 so as to constitute a coolant supply means 12. The cooling liquid supply means 12 draws the cooling liquid in the tank 16 by the pump 15 and jets and supplies the cooling liquid from the cooling liquid jetting pipe 6 to the inner peripheral surface side of the cylindrical body 2, so that the inner peripheral surface of the cylindrical body 2 The cooling liquid layer 3 that flows down while rotating along the peripheral surface is formed.

The coolant tank 16 is provided with a replenishing coolant supply pipe (not shown), and a cooler may be appropriately provided in the tank 16 or in the middle of the circulation channel. Water is generally used as the cooling liquid, but oil may be used in some cases. A discharge port 9 is formed in the bottom wall 2b at the bottom of the cylindrical body 2. The discharge port 9 has a size necessary and sufficient to discharge all the coolant supplied from the coolant supply means 12. In addition, a drain pipe 26 is connected to the outlet 9 and penetrates a collecting body 24 described later.

A plurality of outlets 8 are formed in the lower part of the peripheral wall 2a near the bottom wall 2b upstream of the outlet 9 at intervals in the circumferential direction. The size and shape of the small-diameter holes or slits (small cross-sectional areas) are such that the metal powder flowing down along with the spiral flow of the cooling liquid in the cooling liquid layer 3 is discharged using centrifugal force. But also emits heavy metal powder. At this point, the metal powder is firstly drained.

A recovering body 24 is provided on the cylindrical body 2 so as to cover the bottom portion. The recovering body 24 is recovered by the metal powder recovering body 24 discharged from the discharge port 8 and a liquid removing device such as a centrifugal separator (not shown). And the metal powder is taken out of the cooling liquid after being secondarily drained. Above the cylinder 2, a molten metal supply means 4
An injection crucible (molten metal supply container) 19 that accommodates molten metal as a material is disposed. The injection crucible 19 is formed of a refractory such as graphite or silicon nitride in a cylindrical shape with a bottom, and is opened at the upper end thereof. An induction coil 20 for heating is provided on the outer circumference, and a nozzle hole 2 penetrating inside and outside is provided at the center of the bottom.
1 is formed.

The nozzle hole 21 is located almost directly above the opening 13 of the cylindrical body 2, through which the molten metal passes through the opening 13.
It can be supplied in a substantially vertical direction. Sealing means 7 is provided between the periphery of the upper part of the cylinder 2 and the periphery of the bottom of the injection crucible 19. The sealing means 7 seals the space between the cylinder 2 in the inclined position and the injection crucible 19 in the vertical position, and isolates the space 5 from the nozzle hole 21 to the inside of the coolant layer 3 from the outside. Is an annular member having a triangular shape in a side view and having an internal cavity, and is formed of a refractory material having excellent heat insulating properties, such as ceramic and asbestos.

Further, a suction port 22 is formed through the sealing means 7, and a vacuum pump 23
Are connected to each other to constitute the decompression means 10. The suction port 22 communicates with the space 5 inside the cooling liquid layer 3, and the space 5 is made negative pressure by suction of the vacuum pump 23, and the molten metal is sucked from the nozzle hole 21 facing the negative pressure space 5. Therefore, by adjusting the suction force of the vacuum pump 23,
The amount of molten metal injected from the molten metal supply means 4 to the cooling liquid layer 3 can be controlled.

Although the space 5 appears to be opened by the discharge port 9, the cooling liquid flows through the drain pipe 26 so that the pipe can be closed and the space 5 can be made a closed space. However, by forming the drain trap portion in the middle of the drain pipe 26, the residual cooling liquid allows the drain pipe 2 to be formed.
The airflow in the space 6 may be surely blocked to ensure the airtightness of the space 5.

In order to produce metal powder using the metal powder production apparatus 1A, first, the pump 15
To cause the coolant to be ejected from the coolant ejection pipe 6 along the inner peripheral surface of the cylindrical body 2, thereby forming the spirally flowing cooling liquid layer 3 on the inner peripheral surface of the cylindrical body 2 and the cooling liquid layer 3. A space 5 is formed inside the space. Next, the pressure reducing means 10 is operated, and the air in the space 5 from the inside of the cooling liquid layer 3 to the nozzle hole 21 of the jet crucible 19 is sucked by the vacuum pump 23 to reduce the pressure.
The molten metal in the injection crucible 19 is sucked from 1 and the molten metal is injected and supplied to the cooling liquid layer 3.

The molten metal supplied to the cooling liquid layer 3 is efficiently divided and miniaturized by the cooling liquid in the cooling liquid layer 3 flowing down while turning, and rapidly solidified by cooling. Then, the rapidly solidified metal powder flows downstream with the cooling liquid, is discharged from the discharge port 8 with the cooling liquid, is firstly drained, is conveyed to the dewatering device via the recovery body 24, and is dewatered. Then, the metal powder is taken out by drying with a drying device.

The cooling liquid is discharged from the discharge port 9 through a drain pipe 26, returned to the tank 16, and circulated. Of the molten metal supplied to the cooling liquid layer 3, the metal powder that scatters after colliding with the cooling liquid layer 3 and is not rapidly cooled falls in the space 5, delays cooling, and is discharged together with the cooling liquid from the discharge port 9. It is discharged and separated from the normal metal powder discharged from the discharge port 8.

In the second embodiment shown in FIG. 2, the cylinder 2 of the metal powder producing apparatus 1B is arranged so that its axis is substantially vertical, and the nozzle hole 21 at the bottom center of the injection crucible 19 is formed. Is formed inclined with respect to the perpendicular,
The molten metal is injected obliquely toward the coolant layer 3. The cylindrical body 2 has a large-diameter discharge port 9 substantially at the center of the bottom wall 2b.
Is formed on the inner peripheral surface of the peripheral wall 2a on the upstream side thereof by a bolt so as to be detachable and replaceable with bolts. The cooling liquid layer 3 having a substantially constant thickness is easily formed on the inner peripheral surface. A discharge port 8 having a small cross-sectional area is formed above the ring 28.

The ring 28 not only secures the thickness of the cooling liquid layer 3 but also blocks the metal powder flowing down with the cooling liquid, facilitates centrifugation, and guides the metal powder to the discharge port 8. . The collecting body 24 is formed so as to surround a part of the peripheral wall 2a forming the discharge port 8, and the drainage pipe 26
And try not to interfere.

In the second embodiment, as in the first embodiment, the cooling liquid is also discharged from the discharge port 8, but the metal powder is mainly discharged. It is possible to remove the molten metal slowly and easily separate and remove the molten metal having a low cooling rate. Note that the present invention is not limited to the above embodiment, and can be variously modified. For example, although a cylindrical cylinder is shown as a cooling cylinder, the present invention is not limited to this. For example, a funnel shape or an inverted conical shape in which an inner peripheral surface is formed by a paraboloid of revolution that expands upward is used. , The inclination angle of the cylindrical body 2 with respect to the vertical line can be adjusted, or the bottom of the injection crucible 19 can be formed in a spherical or arc shape to form the sealing means 7.
May be tiltable with respect to.

The present invention is not limited to the production of lightweight metal powders such as Al alloys and Mg alloys, but can of course be applied to the production of metal powders such as iron and its alloys.

[0026]

According to the method of the present invention described in detail above, the metal powder in the cooling liquid layer 3 is moved radially outward of the cylinder 2 by centrifugal force at a position upstream of the position at which the coolant is discharged from the cylinder 2. Release
The metal powder recovery and dewatering process can be simple and easy, the load of the dewatering process can be reduced, the metal powder with slow cooling rate can be discharged together with the cooling liquid, and it can be easily separated and removed from the cooled normal metal powder. .

According to the device of the present invention, the cylinder 2 is located upstream of the discharge port 9 formed at the bottom of the cylinder 2 for discharging the coolant.
Since the discharge port 8 for centrifugally separating the metal powder from the cooling liquid layer 3 is formed on the peripheral wall of the metal powder, the metal powder can be recovered up to the discharge port 9, and the recovery and dewatering steps are simple and easy. It can reduce the load of the dewatering process, discharge metal powder with a slow cooling rate together with the cooling liquid, easily separate and remove it from cooled normal metal powder, and reduce the size of the device.
Can be simplified.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal powder manufacturing apparatus 2 Cylindrical body 3 Coolant layer 4 Molten metal supply means 5 Space 6 Coolant ejection pipe 7 Sealing means 8 Discharge port 9 Discharge port 10 Decompression means 12 Coolant supply means

Claims (2)

(57) [Claims] 1. A cooling liquid layer (3) is formed by swirling a cooling liquid on an inner peripheral surface of a cooling cylinder (2) while forming a cooling liquid layer, and the molten metal is supplied from a molten metal supply means (4). In the method for producing a metal powder, wherein the metal powder is obtained by being supplied to (3) to be cut and solidified by cooling, the method comprises:
A method for producing metal powder, comprising: discharging metal powder in a cooling liquid layer (3) radially outward of a cylindrical body (2) by centrifugal force. 2. A cooling cylinder (2) provided with a cooling liquid ejection pipe (6) for ejecting and supplying a cooling liquid from a tangential direction along an inner peripheral surface, and the cooling liquid ejection pipe (6). A molten metal supply means (4) for supplying molten metal to a cooling liquid layer (3) formed on the inner peripheral surface of the cylindrical body (2) by the cooling liquid ejected from the metal powder producing apparatus; A discharge port (9) formed at the bottom of the cylindrical body (2) for discharging the cooling liquid, and an outlet for centrifugally separating the metal powder from the cooling liquid layer (3) on the peripheral wall of the cylindrical body (2). 8) An apparatus for producing a metal powder, the method comprising: