JPH0417605A - Method and apparatus for manufacturing rapidly solidifying metal powder - Google Patents

Abstract

PURPOSE:To continuously manufacture rapidly solidifying metal powder with good cooling efficiency by forming revolving cooling liquid layer along inner peripheral face of a cylindrical part in a cooling vessel and successively supplying molten metal from inner peripheral face side of the revolving cooling liquid layer. CONSTITUTION:By working a high pressure pump 13, cooling water 6 in a tank 7 is sucked and injection-supplied from upper end outer peripheral side of contracting diameter part 11 in the cooling vessel 1, and the revolving cooling liquid layer 12 is formed along the inner peripheral face of the cylindrical part 2. Successively, the molten metal 18 of the specific temp. in an injection crucible 14 is injected and splashed into the cooling vessel 1 and supplied into the cooling liquid layer 12 from the inner peripheral face side of revolving cooling liquid layer 12 and molten metal particles are quickly cooled and solidified to make the metal powder. The manufactured metal powder is shifted to lower side of inclined direction with a mesh member 8 and discharged and recovered from a guide hole 8, and the cooling water is returned back to the tank 7 and circularly used. By this method, the rapidly solidifying metal powder having high quality is obtd. with high cooling efficiency.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention produces metal powder by rapidly cooling and solidifying the molten metal by supplying molten metal such as aluminum alloy into a cooling liquid layer that moves at high speed. The present invention relates to a method and apparatus for producing rapidly solidified metal powder.

(Prior Art) As a manufacturing apparatus of this type, there is an apparatus having the structure shown in FIG. 4, in which 101 is a bottomed rotating drum having a bottom shape, and an opening 102 is provided on the upper surface. A rotary drive shaft 104 that is rotationally driven by a drive device such as a motor is connected to the center lower surface side of the bottom 103 of the rotary drum 101, and as the rotary drive shaft 104 rotates, the rotary drum 101 rotates around the axis in the vertical direction. Rotationally driven. In addition, the rotating drum 10
1 contains cooling water 105 as a cooling liquid.

106 is a cylindrical injection crucible with a bottom, an injection nozzle 107 is formed on the lower end side, and an injection port 1 is formed on the upper end.
08 is removably attached to a sealing lid 109. Further, a communication passage 110 communicating with the injection crucible lO6 is formed in the lid body 109, and is configured so that a pressurized medium such as argon gas can be supplied into the injection crucible 106.

Reference numeral 111 denotes a high-frequency heating coil as a heating device provided on the outer periphery of the injection crucible 106, and is installed over substantially the entire length of the injection crucible 106 in the vertical direction.

When the rotating drum 101 is rotated, the water 105 is stuck to the inner circumferential surface side in a layer due to centrifugal force of rotation.

On the other hand, inside the injection crucible 106, there is a high frequency heating coil 11.
The molten metal 112 that has been melted and heated to a predetermined temperature by the operation of step 1 is contained, and as the internal pressure is increased by the pressurized pressure medium, the molten metal 112 is ejected and scattered through the injection nozzle hole 107, and is inside the layer of water 105 moving at high speed. By colliding with the peripheral surface, the molten metal particles are visualized, rapidly cooled, and solidified.
A method for obtaining metal powder was used here.

(Problem to be Solved by the Invention) However, according to the above method, once the metal powder spouted into the water 105 of the rotary drum 101 and cooled and solidified reaches a predetermined amount, the rotation of the rotary drum 101 is stopped. Since it is a so-called batch method in which the produced metal powder must be taken out from inside the rotary drum 101, metal powder cannot be produced continuously and has the disadvantage of poor productivity. In addition, the water 105 is rotated as the rotating drum 101 rotates, and the water 105 is stuck and held in a layer on the inner circumferential surface of the rotating drum 101 by centrifugal force.
Therefore, as shown in FIG. 5, when the molten metal particles or semi-solidified particles reach the inner surface of the drum due to centrifugal force, the layer of water 105 that moves at high speed and is formed on the inner peripheral surface of the rotating drum 101 becomes thicker. This is equivalent to the state in which the molten metal 112 is supplied into the water 105, which is considered to be relatively stationary in the horizontal direction, and the steam generated around the molten metal particles 113 is difficult to separate, resulting in poor cooling efficiency. there were. Furthermore, since the molten metal particles are always supplied on the same surface, the water temperature in this area partially increases, causing variations in the cooling rate.

Therefore, in view of the above-mentioned problems, the present invention provides a cooling system with high cooling efficiency.
Moreover, it is an object of the present invention to provide a manufacturing method and a manufacturing apparatus that can continuously manufacture rapidly solidified metal powder.

(Means for Solving the Problems) The method of the present invention, which has been made to achieve the above object, involves supplying molten metal into a cooling liquid layer moving at high speed, and rapidly solidifying metal powder to obtain metal powder. In the manufacturing method, a cooling liquid is supplied from the outer peripheral side of the upper end of the cylindrical part of a cooling container having a cylindrical part whose inner peripheral surface is a downward cylindrical surface, and is caused to swirl along the inner peripheral surface of the cylindrical part. At the same time, the centrifugal force caused by the swirling forms a layered swirling cooling liquid layer with a cavity in the center, and the molten metal is supplied from the inner circumferential surface of this swirling cooling liquid layer to cause it to solidify. , to obtain metal powder.

Further, the apparatus of the present invention for carrying out the above method includes a cooling container having a cylindrical part whose inner peripheral surface is a downwardly cylindrical surface, and a swirling flow formed from the outer peripheral side of the upper end of the cylindrical part. A cooling liquid supply mechanism that jets out and supplies a cooling liquid and causes it to flow down while forming a layered swirling cooling liquid layer with a hollow center on the inner circumferential surface of a cylindrical part due to the centrifugal force effect caused by the swirling of the cooling liquid. and a molten metal supply mechanism that supplies molten metal into the cooling liquid layer from the inner peripheral surface side of the swirling cooling liquid layer. In this case, a ring for adjusting the layer thickness of the swirling cooling liquid layer may be attached to the lower inner circumferential surface of the cylindrical portion.

(Function) According to the manufacturing method of the present invention, by supplying the cooling liquid 6 in the circumferential direction from the outer peripheral side of the upper end of the cylindrical part 2 of the cooling container 10, the cooling liquid 6 flows down while swirling along the inner peripheral surface of the cylindrical part 2. By forming a swirling cooling liquid layer 12 and sequentially supplying molten metal 18 from the inner peripheral surface side of this swirling cooling liquid layer 12, rapidly solidified metal powder can be continuously produced.

Furthermore, the flow velocity in the thickness direction of the swirling cooling liquid layer 12 has a so-called inclined velocity distribution in which the velocity increases as it approaches the center of swirling, so the molten metal particles that have entered the swirling cooling liquid layer 12 are given rotational motion. At the same time, even if molten metal particles or semi-solidified particles reach the inner surface of the cooling container, they will move in the same way as water.
The steam generated around the molten metal particles is effectively released, improving the cooling rate. Furthermore, since the water always moves downward due to gravity, molten metal particles are always supplied to the water area under the same conditions, which reduces variations in the cooling rate.

On the other hand, according to the manufacturing apparatus of the present invention, the cooling container 1 is installed in a fixed manner, and the cooling liquid 6 is supplied circumferentially from the outer circumferential side of the upper end of the cylindrical part 2 by the operation of the cooling liquid supply mechanism. A moving swirling cooling liquid layer 12 can be easily formed,
The device can be made more compact. In addition, by providing a layer thickness adjustment ring 20 on the lower inner peripheral surface of the cylindrical portion 2,
Since the swirling cooling liquid layer 12 flows down beyond the inner peripheral surface of the ring 20, the layer thickness of the swirling cooling liquid layer 12 can be easily adjusted by changing the radial thickness of the ring 20. be able to.

(Example) Hereinafter, a manufacturing apparatus for carrying out the manufacturing method of the present invention will be described. In FIG. A cylindrical portion 2 having a downwardly cylindrical inner circumferential surface is connected to the lower end of the reduced diameter portion 11, and the lower end of the cylindrical portion 2 has a diameter gradually increasing downward. An enlarged diameter portion 3 is provided in an extending shape, and the upper end of the reduced diameter portion 11 is closed by a lid portion 5 having an appropriately sized introduction hole 4 in the center. The cooling container 1 is fixedly installed with the axis of the cylindrical portion 2 tilted at an appropriate angle. A layer thickness adjustment ring 20 is removably screwed to the lower inner circumferential surface of the cylindrical portion 2 and is formed into a streamlined curved surface along the inner circumferential surface from the upper end to the lower end. Further, the lower end of the cooling container 1 is connected to a tank 7 in which cooling water 6 as a cooling liquid is stored, as appropriate. Reference numeral 8 denotes a mesh member detachably or fixedly attached to the lower part of the enlarged diameter part 3, which allows the cooling water 6 to pass downwardly and partitions the lower part of the enlarged diameter part 3 in the vertical direction, and which is inclined sideways. A guide port 9 for rapidly solidified metal powder is appropriately formed in the circumferential wall of the enlarged diameter portion 3 on the lower end side in the inclined direction. The layer thickness adjustment ring 20 may be screwed on if necessary, or may remain removed.

The outer circumferential side of the upper end of the reduced diameter part 11 is inclined tangentially or slightly toward the center (for example, θ=0 to 2 with respect to the tangential force/direction).
0') is provided, and the discharge port of the high-pressure pump 13 and the coolant introduction path 10 are connected by piping. Further, a suction port of the high-pressure pump 13 is connected to a pipe to suck the cooling water 6 in the tank 7 .

Then, by operating the high-pressure pump 13, the cooling water 6 is sucked into the tank 7 and jetted out from the outer circumferential side of the upper end of the reduced diameter portion 11, thereby forming a swirling flow. - The swirling flow is accelerated as it flows down the diameter-reduced portion 11, and is supplied to the inner circumferential surface of the cylindrical portion 2 from the outer circumferential side of the upper end of the cylindrical portion 2 in the circumferential direction. The swirling flow flows down along the inner peripheral surface of the cylindrical portion 2 while forming a layered swirling cooling liquid layer 12 with a hollow center side due to the centrifugal force caused by the swirling, and a cooling liquid supply mechanism is formed here. do. The cooling water 6 that has flowed down passes through the mesh member 8 and is returned into the tank 7.

Note that a cooler may be appropriately interposed in the piping from the tank 7 to the high-pressure pump 13 to cool the cooling water.

14 is an injection crucible as a molten metal supply mechanism, which is made of a refractory material such as graphite or silicon nitride, and is formed into a cylindrical shape with a bottom.
The upper part is provided with a lid and a pressurized medium supply section, as in the conventional case. Furthermore, an injection nozzle hole 16 is formed in the bottom portion 15 of the injection crucible 14 . Reference numeral 17 denotes a high-frequency heating coil as a heating device provided around the outer periphery of the injection crucible 14.

Then, the injection crucible 1 is heated by the operation of the high-frequency heating coil 17.
The molten metal 18 is heated to a predetermined temperature by melting the metal lump such as aluminum alloy housed in the molten metal 18. It is ejected and scattered from the injection nozzle hole 16, and is supplied into the cooling liquid layer 12 through the introduction hole 4 from the inner peripheral surface side of the swirling cooling liquid layer 12 formed in a sticking manner on the inner peripheral surface side of the cylindrical part 2.

Next, a method for producing rapidly solidified metal powder using the above apparatus will be described.

First, the high-pressure pump 13 is activated, and the swirling cooling liquid layer 12 flows down while moving at high speed onto the inner peripheral surface of the cylindrical part 2 of the cooling container 1.
form.

Next, the molten metal 1 in the injection crucible 14 is heated to a predetermined temperature.
8 is spouted and scattered and supplied into the cooling liquid layer 12 from the inner peripheral surface side of the swirling cooling liquid layer 12.

By supplying the coolant into the cooling liquid layer 12, the molten metal particles are rapidly cooled and solidified to obtain metal powder.

Then, the metal powder flows down together with the cooling water 6, and is stopped by the mesh member 8 at the bottom of the cooling container 1.
It is moved downward in the direction of inclination, is discharged and guided through the guide port 9, and is collected as appropriate. On the other hand, the cooling water 6 is supplied to the mesh member 8
The water passes through the tank 7 and is returned to the tank 7 for circulation.

According to the above manufacturing method, if the molten metal 18 is continuously supplied, rapidly solidified metal powder can be continuously manufactured in sequence, and productivity is improved.

In addition, since this is a method of supplying cooling water 6 in the circumferential direction from the outer circumferential side of the upper end of the cylindrical part 2 of the cooling container 1 installed in a fixed manner to form a swirling cooling liquid layer 12 that moves at high speed, the flow velocity is It is inversely proportional to the distance from the center, as shown in Figure 2,
Velocities in the thickness direction of the swirling cooling liquid layer 12 V+, Vz, v3.
Vs, ----- has a so-called inclined velocity distribution in which the speed is higher on the swirling center side, and the molten metal particles 19 are supplied from the inner peripheral surface side into the swirling cooling liquid layer 12 of the flow with this inclined velocity distribution. Become. Therefore, since the flow velocity of the swirling cooling liquid layer 12 differs in the thickness direction, the molten metal particles 19 are given rotational motion, and even if the molten metal particles or semi-solid particles reach the inner surface of the cooling container, they move in the same way as water. The steam generated around the molten metal particles 19 is easily separated by the rotation of the molten metal particles 19, which improves the cooling rate of the molten metal particles 19, increases the heat transfer coefficient, improves the cooling efficiency, and improves the cooling capacity. High quality rapidly solidified metal powder can be obtained.

Further, according to this device, the cooling container 1 is installed in a fixed manner, and the cooling water 6 is jet-supplied to form the swirling cooling liquid layer 12. As in the conventional system, the cooling water is stored in the rotating drum 101. However, compared to a method in which the cooling liquid layer is formed by rotating the rotary drum 101 itself, this method has the advantage that the device itself can be configured more compactly. Furthermore, by adjusting the hole diameter of the coolant introduction path 10 and the flow rate of the coolant, it is also easy to change the layer thickness and flow rate of the swirling coolant layer 12.

Although the above embodiment shows a structure in which the molten metal 18 is ejected and scattered from the injection crucible 14, a gravity fall method may be used in which the molten metal 18 is dropped into the swirling cooling liquid layer 12 from the hole at the bottom end of the crucible. . Furthermore, although the cylindrical portion 2 is shown with its axis set in an inclined manner, it may be arranged such that the axis is set in the vertical direction and the molten metal 18 is ejected and scattered from the inclined direction. Furthermore, the discharge amount and discharge pressure of the high-pressure pump 13, the shape and size of the funnel portion 2, etc. may be determined as appropriate.

In the above embodiment, as the cooling container 1, the reduced diameter part 1 is smaller than the lid part 5.
A cylindrical part 2 is formed through the cylindrical part 1, and an enlarged diameter part 3 is connected to the lower end of the cylindrical part 2. However, the reduced diameter part 11 and the enlarged diameter part 3 are not necessarily necessary, and as shown in FIG. The cylindrical portion 2 may be directly formed below the cooling liquid introduction path 10 with the coolant introduction path 10 interposed therebetween. In this embodiment, the layer thickness adjustment ring 20 is removably fitted into an enlarged diameter stepped portion 21 formed on the inner peripheral surface of the lower part of the cylindrical portion 2, and is supported by a fixing ring 22 screwed onto the lower end of the group 21. has been done.

(Effects of the Invention) As explained above, according to the manufacturing method of the present invention, the cooling liquid is supplied from the outer peripheral side of the upper end of the cylindrical part of the cooling container having the cylindrical part whose inner peripheral surface is a downward cylindrical surface. The cooling liquid is supplied in the direction of the cylinder and is caused to flow down while swirling along the inner peripheral surface of the cylinder, and due to the centrifugal force effect of the swirling, a layered swirling cooling liquid layer with a cavity on the center side is formed, and the inside of this swirling cooling liquid layer is Metal powder is obtained by supplying molten metal from the peripheral side and rapidly solidifying it.It has good cooling efficiency and high quality rapidly solidified metal powder with high cooling ability, and it can be manufactured continuously. This has the advantage of being highly productive.

Further, according to the manufacturing apparatus of the present invention, there is no need to rotate the cooling container itself at high speed, and a swirling cooling liquid layer that moves at high speed can be easily obtained, and the apparatus can be made more compact. Further, by attaching a layer thickness adjustment ring to the lower inner peripheral surface of the cylindrical portion where the swirling cooling liquid layer is formed, the thickness of the swirling cooling liquid layer can be easily adjusted.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic explanatory diagram showing an example of a manufacturing apparatus for carrying out the present invention, FIG. 2 is a partial explanatory diagram of a swirling cooling liquid layer,
FIG. 3 is a cross-sectional view of a cooling container according to another embodiment, FIG. 4 is a cross-sectional explanatory view of a conventional device, and FIG. 5 is a partial explanatory view of a swirling cooling liquid layer of a conventional example. 1...-cooling container, 2-cylindrical part, 6-cooling water, 12 swirling cooling liquid layer, 14--injection crucible, 18-molten metal, 20
- Ring for layer thickness adjustment. Diagram

Claims (3)

[Claims] (1) Molten metal (1
8) in a method for producing a rapidly solidified metal powder in which metal powder is obtained by supplying and rapidly solidifying metal powder, the cylindrical part (2) of a cooling container (1) having a cylindrical part (2) whose inner peripheral surface is a cylindrical surface. The cooling liquid (6) is supplied from the outer circumferential side of the upper end in the circumferential direction and flows down while swirling along the inner circumferential surface of the cylindrical part (2), and the centrifugal force of the swirl creates a cavity on the center side. Rapid cooling characterized by forming a layered swirling cooling liquid layer (12), supplying molten metal (18) from the inner circumferential side of this swirling cooling liquid layer (12) and rapidly solidifying it to obtain metal powder. A method for producing solidified metal powder. (2) A cooling container (1) having a cylindrical part (2) whose inner peripheral surface is a downwardly cylindrical surface, and a cooling liquid flowing from the outer peripheral side of the upper end of the cylindrical part (2) to form a swirling flow. (6) is supplied from the circumferential direction, and due to centrifugal force due to the swirling of the cooling liquid (6), a layered swirling cooling liquid layer (12) with a hollow center side formed on the inner circumferential surface of the cylindrical portion (2) is created. and a molten metal supply mechanism that supplies molten metal (18) into the cooling liquid layer (12) from the inner peripheral surface side of the swirling cooling liquid layer (12). Rapid solidification metal powder manufacturing equipment characterized by: (3) Claim (2), wherein a ring (20) for adjusting the layer thickness of the swirling cooling liquid layer (12) is attached to the inner peripheral surface of the lower part of the cylindrical portion.
rapid solidification metal powder production equipment.