JPS63238204A - Apparatus for production powder - Google Patents

Abstract

PURPOSE:To prevent deposition of the liquid drops of a molten metal splashed from a high-speed rotating body to the inside wall of a chamber of an apparatus for cooling said liquid drops by a gas having a high heat conductivity by forcibly cooling and rotating a cylindrical cooling wall against which the above-mentioned liquid drops collide. CONSTITUTION:The chamber 50 houses the apparatus for producing the powder, is provided with an introducing port for an atmospheric gas such as Ar or the is held in the atmosphere of said gas. The molten metal 23 in a vessel 21 falls from a nozzle 22 onto a disk 24 rotating at a high speed and splashes in the form of the liquid drops 51 which collide against the inside wall of the cooling wall 52. The position of the cooling wall 52 against which the liquid drops 51 collide is cooled with water; in addition, the cooling wall 52 is rotated around a shaft 55 by a gear 58 engaged with the circumference of said wall. The liquid drops 51 are, therefore, cooled and solidified instantaneously by collision against the inside surface of the cooling wall 52 and are crushed and splashed again by the impact at the time of collision as the cooling wall 52 rotates. The splashed liquid drops fall in the form of fine powder 52. The deposition of the liquid drops 51 on the inside surface of the cooling wall 52 is, therefore, obviated and the working efficiency of the apparatus is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a powder manufacturing apparatus for manufacturing metal powder used in powder metallurgy and the like.

[Conventional technology]

Powder metallurgy is a technology for manufacturing metal products or metal ingots by charging metal or alloy powder into a mold, pressurizing it, and then sintering the molded body. In powder metallurgy, segregation of component elements does not occur, it is possible to commercialize materials that are difficult to process, it is possible to obtain parts with extremely fine crystal structures, and it is possible to make non-equilibrium phases appear. There are various advantages that cannot be obtained with melted lumber, such as this, and there is also the advantage that secondary cutting can be omitted. For this reason, various powder manufacturing techniques applied to powder metallurgy have been developed.

Among these, as substitute devices for producing powders of Ti, Ti alloys, high alloys, etc., there are devices using a rapid solidification method using centrifugal force, a rotating electrode method, a centrifugal granulation method, and the like.

FIG. 7 is a schematic diagram showing an apparatus for rapid solidification.

In this device, by applying a high frequency current to a high frequency coil 22, a metal lump is melted in a container 21, and the generated molten metal 23 is dropped onto a disk 24 rotating at high speed, and the rotation of this disk 24 causes the molten metal 23 to be scatter. Then, this scattered melt #h23 is rapidly solidified using a cooling medium with high thermal conductivity such as hydrogen gas or helium gas.

FIG. 8 is a schematic diagram showing an apparatus for the rotating electrode method.

In this device, an arc 33 is generated between a consumable electrode 31 and a non-consumable electrode 32, and at this time, the consumable electrode 3 is rotated at high speed by a rotating means (not shown) such as a motor.
The powder 35 is obtained by scattering the droplets 34f generated by the melting of the consumable electrode 3.

FIG. 9 is a schematic diagram showing an apparatus for centrifugal granulation.

This device consists of four crucibles that are rotatably installed in an argon gas atmosphere, and four t-poles that are installed vertically.
Droplets 44 are formed by generating an arc 43 between the electrodes 42 and rotating the crucible 41 while cooling it with water to melt the electrodes 42.
By dropping the liquid into the crucible 41, the droplets 44 are scattered and powder is generated.

[Problem that the invention seeks to solve]

In the above-mentioned prior art, droplets of molten metal scattered from a high-speed rotating body such as a disk or a consumable electrode crucible solidify into powder during the scattering. However, the cooling rate of droplets is slow when cooled only by atmospheric gas such as argon gas or helium gas, and the particle size of droplets is not uniform, so droplets with large particle sizes remain as droplets. It may adhere to the inner wall of the chamber 50. g. When the droplets adhere to the inner wall, they solidify and adhere to the bath. Then, some of it peels off during operation, becomes fragments, and mixes into the powder, making it necessary to sort and remove it. Furthermore, if the weld remains on the inner wall, the device must be stopped periodically to remove it, which lowers the operating rate of the device and requires a great deal of labor.

One possible way to prevent droplets from adhering to the inner wall of the chamber is to make the chamber larger and increase the cooling time of the droplets, but this would make the entire device too large and would not be a disaster. do not have.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a powder manufacturing apparatus that prevents droplets of molten metal from welding to the inner wall of a chamber.

[Means for solving problems]

The present invention includes a rotating body that scatters molten metal into droplets, a rotating means for the rotating body, and a rotating cylindrical body that surrounds the rotating body and is placed at a position where the flying droplets collide. This is a powder manufacturing apparatus comprising a cooling wall, cooling means for the cooling wall, and rotation means within a chamber.

[Effect]

The molten metal is dispersed into droplets by the centrifugal force of the rotating body,
The droplets are caused to collide with the inner surface of a cooling wall that surrounds the rotating body. Since this cooling wall is forcibly cooled and rotates once, the droplets are rapidly cooled and solidified and become powder without being welded to the cooling wall.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a sectional view schematically showing an apparatus according to an embodiment in which the present invention is applied to a rapid solidification method. Also, Figure 2 is
This is a plan view of the cooling wall 52 and its connecting portion in the figure.

In FIG. 1, a chamber 50 houses an apparatus for manufacturing powder, and is provided with an inlet for atmospheric gases such as argon gas and helium gas, and is maintained under an atmosphere of these gases. A container 21 stores molten gold 7423 having the same composition as the powder to be manufactured, and a nozzle 22 is provided at the bottom of the container to drop an appropriate amount of molten metal 23 feet. A disk 24, which is a rotating body, is installed below the nozzle 22 and is rotated at high speed by a rotating device (not shown) to scatter the fallen molten metal 23 into droplets 51. A cooling wall 52 that surrounds the disk 24 and is water-cooled and rotates is arranged at a position where the scattered droplets 51 collide with each other. The cooling wall 52 is connected to a shaft 55 by a plurality of connecting frames 54 as shown in FIG.
It is driven from the outside and rotates around a shaft 55. Also, the cooling wall 5
2. The connecting frame 54 and the shaft 55 are each hollow and divided into two parts to form a cooling water flow path.

A cooling water pipe 56 is connected to the shaft 55, and the cooling water passes through the aforementioned cooling water flow path and is discharged from a cooling water outlet 57.

In such an apparatus, the molten metal 23F in the container 21
It falls from the i-nozzle 22 onto a disk 24 rotating at high speed. The fallen molten metal 23 becomes droplets 51 and scatters. This droplet 5J collides with the cooling wall in the summer, cools and solidifies,
It falls as fine powder 53. On this occasion, cooling wall 5
Since the cooling wall 52 is kept at a low temperature, the droplet 51 that collides with the liquid droplet 51 is instantly cooled down, and since the cooling wall 52 is rotating, the droplet 51 is crushed by the impact at the time of collision and is scattered again. Therefore, welding of the droplets 51 to the inner surface of the cooling wall 52 does not occur, and the rotational speed of the cooling wall 52 is preferably a circumferential speed of 10 m/sec or more.

FIG. 3 is a cross-sectional view schematically showing an apparatus according to another embodiment in which the present invention is applied to a rapid solidification method, in which atmospheric gas is introduced into the chamber 50 as a medium for cooling the cooling wall 52. This is the device used.

In this device, a disk 24 is a rotating body that rotates molten metal 23 from a container 21 through a nozzle 22 at high speed.
It is dropped onto the top to form droplets 51 and scatter. The droplet 51 then collides with the inner wall of a cooling wall 52 that is arranged around the disk 24 and rotates once while being cooled by atmospheric gas, and rapidly cools and solidifies, becoming a fine powder 53 and falling. . In addition.

Since the cooling wall 52 is rotating, atmospheric gas is blown over the entire circumference, and the entire wall surface is uniformly cooled.

FIG. 4 is a schematic diagram showing an embodiment of an atmospheric gas blowing device. This device is close to the outer periphery of the cooling wall 52,
A fixed cover 60 is installed to cover the outer surface. If this cover 60 is installed, all the atmospheric gas introduced from the cooling gas introduction '1f59 will be transferred to the cooling wall 5.
Since it is used for cooling No. 2, the cooling efficiency is improved. In addition,
It is preferable to attach a flexible sealing material 61 to the inner periphery of the cover 60 for simple sealing. Moreover, if the atmospheric gas is cooled and introduced, the cooling effect can be further enhanced. Although the device that cools the cooling wall 52 with atmospheric gas as in this embodiment has lower cooling efficiency than the device that cools it with water,
It has the advantage of having a simple structure.

FIG. 5 shows an example in which the shape of the cooling wall 52 is changed, and the cylindrical cooling wall 52 has a lower portion larger than an upper portion and a trapezoidal cross section.

This shape was designed to allow the powder 53 generated on the inner surface of the cooling wall 52 to fall easily. As mentioned above, droplet 5
1 is not welded to the cooling wall 52, but
When the cooling wall 52 has an upright cylindrical shape as in the embodiment shown in the figure, since the cooling wall 52 is rotating, depending on its rotational speed, the powder 53 may fall down slightly due to the action of centrifugal force. amount may be resistant to adhesion. If the powder 53 adheres to the cooling wall 52, the cooling efficiency will decrease, which is not preferable. Figure 5 takes this situation into consideration, and Figures 1, 3,
The present invention can also be applied to any of the embodiments shown in FIG.

FIG. 6 is a sectional view schematically showing an apparatus according to an embodiment in which the present invention is applied to a rotating electrode method.

In FIG. 6, chamber 50 is filled with argon gas.

It is kept under an atmospheric gas such as helium gas, and a device for producing powder is housed inside. 31 is a consumable electrode which is a rotating body rotated at high speed by a rotating means (not shown).

A non-consumable electrode 32 is arranged at a position facing the consumable electrode 31, and a power supply 62 generates an arc 33 between the consumable electrode 31 and the tip of the consumable electrode 3 to melt the droplet 51. It is designed to generate. Consumable electrode 3
A cooling wall 52 that is cooled and rotates is disposed surrounding the radial circumference of the liquid @ 51 at a position where the liquid @ 51 collides with the liquid @ 51 . The cooling wall 52 is cooled by blowing atmospheric gas such as argon gas or helium gas introduced from a cooling gas introduction pipe 59 onto its outer surface. Further, the cooling wall 52 is connected by a connecting culm 54 to an annular member 64 that slides on a shaft 63 identified in the chamber 5o, and is rotatable. The cooling wall 52 is configured to rotate around a shaft 63 by a rotating device (not shown) connected to a gear 58 meshing with the outer periphery of the cooling wall 52 .

In an apparatus having such a structure, first, the power supply 62 supplies power to the consumable electrode 31 and the non-consumable electrode 32 to generate an arc 33 between the two electrodes, thereby melting the tip of the consumable electrode 31. Since the consumable electrode 31 is rotating at high speed, the molten metal generated by melting the consumable electrode 31 becomes a liquid @5x and scatters.

This droplet 51 collides with the inner surface of a cooling wall 52 arranged around the consumable electrode 31 . Since the outer surface of the cooling wall 52 is cooled by the atmospheric gas introduced from the atmospheric gas introduction pipe 59, the colliding droplets are cooled and solidified at the same time as the collision, and fall as fine powder 53.

Next, a specific example of actually producing powder according to the present invention will be described. The material used is the N1 group high alloy shown in Table 1.

The apparatus has the configuration of the embodiment shown in FIG.

The chamber has a diameter of 2.2 m, and a high-frequency melting furnace (
The disk 24 has a diameter of 90 m,
The rotation speed is 15,000 rpm, and the cooling wall 52 is made of stainless steel and has a diameter of 2 m, a height of 200 mm, and a rotation speed of 200 r.
It was set as pm. Using this device, molten metal was dropped onto the disk 24 at a pouring rate of 7 kll 1 minute, and the disk 240 rotated to form 5 droplets, which were made to collide with the cooling wall 52 to produce powder. After this operation was continued for t-2 minutes, the interior was inspected and it was found that it was summer so that hardly any welds were observed on the cooling wall 52F3 surface. Moreover, the obtained powder has an average particle size of 1
It was a rapidly solidified powder with a non-equilibrium phase and a fine crystal structure.

For comparison, when powder was produced under the same conditions as described above using an apparatus without the cooling wall 52, the amount of powder deposited on the inner wall of the chamber 50 was approximately 1 kg, which was the average particle size of nine powders. The diameter was 220μ.

〔Effect of the invention〕

As described above, according to the present invention, molten metal is not welded not only to the inner wall of the chamber but also to the cooling wall, so there is no need to remove welded material or sort out separated welded material. Therefore, the operating rate of the device is improved and the work is simplified.

Further, since the size of the chamber can be designed solely for the original purpose of holding the chamber under atmospheric gas, the chamber can be made smaller. Furthermore, since the cooling wall is forcedly cooled, a non-equilibrium phase quenched powder having a fine crystal structure can be obtained, and since the cooling wall is rotating, the obtained powder can be made fine.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an apparatus according to an embodiment in which the present invention is applied to a rapid solidification method. FIG. 2 is a plan view showing the cooling wall and its connecting portion in FIG. 1. FIG. 3 is a schematic diagram showing another embodiment in which the present invention is applied to a rapid solidification method. FIG. 4 is a schematic diagram showing an embodiment of a spraying device with a gas atmosphere. FIG. 5 is a schematic diagram showing an example of another shape of the cooling wall. FIG. 6 is a schematic diagram showing an embodiment in which the present invention is applied to a rotating electrode method. Figures 7 to 9 are schematic diagrams showing conventional powder manufacturing equipment, with Figure 7 showing the rapid solidification method and Figure 8 showing the rotating! Figure 9 shows the centrifugal granulation method. 23... Molten metal, 24... Disc, 3...
Consumable electrode, 33... Arc, 60... Chamber, 5
1...Liquid space, 52...Cooling wall, 53...Powder. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Figure 9 Procedural Amendments Showa -20, 30B 1, Case Indication Patent Application 1986- 71644 No. 2, Name of the invention Powder manufacturing device 3, Relationship with the amended case Patent applicant (412) Nippon Kokan Co., Ltd. 4, Agent UBE Building 7, 3-7-2 Kasumigaseki, Chiyoda-ku, Tokyo;
Contents of the amendment (1) In the middle box of the specification, page 12, line 8 (line 12 from the bottom), ``Diameter 2 mJ'' is corrected to ``diameter 1.2 mJ.'' (2) Page 12, line 15 (line 12 from the bottom) line 5) with “170μ
" is corrected to "80μ".

Claims (3)

[Claims] (1) A rotating body that scatters molten metal into droplets, a cylindrical cooling wall that surrounds the rotating body at a position where the droplets collide, a cooling means that forcibly cools this cooling wall, and a cooling means that forcibly cools the cooling wall. A powder manufacturing apparatus comprising a chamber and a rotation means for rotationally driving a wall. (2) The powder manufacturing apparatus according to claim 1, wherein the rotating body is a disk that scatters the molten metal falling onto its upper surface into droplets. (3) The powder manufacturing apparatus according to claim 1, wherein the rotating body is a consumable electrode whose tip is melted by an arc.