JPS63210206A - Apparatus for producing metal powder - Google Patents

Abstract

PURPOSE:To provide the titled apparatus which permits easy production of high-purity powder by providing a plasma gun which melts the end of a hung and held melting material to form liquid drops and a rotary disk for splashing and cooling the falling liquid drops, etc., into a chamber in which a cooling gas is filled. CONSTITUTION:The end of the hung and held melting material 11 is melted by an arc jet 16 of the plasma gun 12 and the liquid drops 13 of the molten metal formed in such a manner are dropped onto the disk 4. The disk 14 is kept rotating at a high speed, for example, 30,000rpm by a rotating device 15 during this time. The falling liquid drops 13 are, therefore, splashed and are quickly cooled by the cooling gas 17 filled in the chamber 19, by which powder 18 is formed. Since the plasma gun is used for melting of the melting material with the apparatus for producing the metal powder of this invention, the high-pressure atmosphere of the cooling gas can be formed in the chamber. An increase in the size of the melting material is thereby permitted and the productivity is improved. In addition, the high-purity powder is produced by installing the chamber to a required size.

Description

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

[Prior Art] Powder metallurgy is a technology for producing metal products or metal ingots by charging metal or alloy powder into a mold, press-molding 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, it is possible to make non-equilibrium phases appear, etc. ,
There are various advantages that cannot be obtained with melt-sawn lumber, 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 methods, the rapid solidification method is one of the methods that can produce powder with a fine and uniform structure on an industrial production scale.

FIG. 2 is a schematic diagram showing the rapid solidification method. In this rapid solidification method, a molten metal 3 is produced by melting a metal lump in a container 2 by applying a high frequency current to a high frequency coil 1.
is dropped through a nozzle 4 onto a disk 5- which rotates at high speed, and the rotation of this disk 5 scatters the molten metal 3.

Then, this scattered molten metal 3 is rapidly solidified using a cooling medium with high thermal conductivity such as hydrogen gas or helium gas. However, container 2. There is a risk that impurities may enter from the nozzle 4. As a method for preventing such contamination with impurities, there is a centrifugal granulation method as shown in FIG. Here, an arc 8 is generated between the rotating crucible (water-cooled electrode) 6 and the consumable electrode (vertical) 7 in an Ar atmosphere in a chamber (not shown), and the end of the consumable electrode 7 is melted into the rotating crucible 6. The dropped liquid droplets are scattered by high-speed rotation of the rotating crucible 6 to form powder 9.

[Problems to be Solved by the Invention] However, the above-mentioned centrifugal granulation method has the risk of contamination from the rotating crucible, and also requires the rotating crucible to be rotated at high speed (to obtain powder with a small free-standing diameter). Therefore, high-speed rotation of the rotating crucible is essential.

Therefore, there are problems in mounting the rotating crucible with accuracy, the rotation mechanism, water cooling device, etc. are complicated, making it difficult to increase the size of the equipment, and low productivity.

The object of the present invention was made in view of the following circumstances, and it is an object of the present invention to provide a metal powder manufacturing apparatus that can easily manufacture high-purity powder of Ti, Ti alloy, high alloy, superalloy, etc. on an industrial production scale. This is what we are trying to provide.

[Means for Solving the Problems] The present invention provides a suspension-held melting material, a plasma gun for melting the V section of the melting shrine to form droplets of molten metal, and a droplet formed by the plasma gun. A metal disk is installed in a chamber filled with cooling gas, and includes a disk placed at a position where the droplets fall, and a rotating means that rotates the disk to scatter and cool the falling droplets into powder. It is characterized by a powder manufacturing device.

[Effect 1] According to this structure, the end of the molten metal is heated by a plasma gun in the chamber, forming droplets of molten metal, which fall onto the rotating disk. The droplets are cooled by the cooling gas that fills the chamber and form powder.

[Example] The present invention will be specifically described below with reference to the accompanying drawings. FIGS. 1(a) and 1(b) show a powder manufacturing apparatus according to the present invention. In FIG. 1(a), the molten material 11 held suspended is connected to the arc jet 16 of the plasma gun 12.
melting its ends to form a droplet 13 of molten metal;
It falls onto the disk 14. In this case, the disk 14 is rotated at high speed by a rotating device 15, for example, 3'0. 00 or
pm', the falling droplets 13 scatter and are rapidly cooled by the cooling gas 17 filling the chamber 19 to form a powder 18. The chamber 19 is provided with a cooling gas supply port 20 and a gas discharge port 21 .

A rotating device 22 is provided so that the melting material 11 can rotate around an axis extending in the vertical direction. The rotation is gentle (
For example, at 2 rpm), the end portion of the melt H is melted uniformly. Further, the melting material is provided with a feeding device 23 for feeding the melting material 11 downward in response to the melting of the end portion thereof.

This makes it possible to keep the end of the melting material 11 constant at all times. FIG. 1(b) is an enlarged detailed view of the plasma gun 12. Commercially available plasma guns can be used.

Here, a working gas 26 is flowed between the cathode 24 and the anode 25 to form an arc jet 16.

In the present invention, a plasma gun is used to melt the ends of the melting material. The reason for this is that unlike an electron gun, a plasma gun does not require a high degree of vacuum in the chamber (e.g., 10-' Torr or less) and can operate at 1 atm.
This is because the inside of the chamber can be maintained in an atmosphere of high-pressure cooling gas (for example, helium gas). Therefore, the formed droplets fall onto the disk and are scattered, contacting the cooling gas and rapidly forming powder. In this case, the droplet can be completely solidified before colliding with the inner wall of the chamber, so that it will not adhere to the inner wall of the chamber. Therefore, compared to the case where a cooling gas cannot be used, such as when an electron gun is used, the distance from the disk to the inner wall of the chamber can be shortened, and the diameter of the chamber itself can be reduced to about 1/10.

Next, an experimental example using a powder manufacturing apparatus as shown in FIG. 1 will be shown.

Experimental Example A Ti-6AJ2-4V alloy was used as the melting material. This was melted by VAR melting to create a melted material with a diameter of 120 mm. While rotating this melting material at 2 rpm,
The ends of this melted material were melted using a 50KW plasma gun. The diameter of the lower disk was 90 mmφ, the rotational speed of the disk was 30,000 ppm, and the molten droplets were dropped onto the second disk and scattered to obtain a powder of about 120 μm. This was a highly pure Ti-6A, ff-4V alloy powder.

In this case, the working gas of the plasma gun is helium gas, and the chamber contains helium gas 1a as a cooling gas.
tril was used. The operating gas and the cooling gas do not have to be used at the same time.

[Effect of the invention] The metal powder manufacturing apparatus according to the present invention uses a melting material,
Since a plasma gun is used for melting, a high pressure cooling gas atmosphere can be created within the chamber. Therefore, in addition to improving productivity by increasing the size of the melting material, it is also possible to manufacture high-purity powder by installing a chamber of a required size, making it an invention with high industrial utility.

[Brief explanation of the drawing]

Detailed drawings of the Zuma gun, FIGS. 2 and 3 are schematic diagrams showing a conventional powder manufacturing apparatus. 11... Melting material, 12... Plasma gun, 13...
Droplet, 14... Disk, 15... Rotating device, 16
... Arc jet, 17... Cooling gas, 18.
...Powder, 19...Chamber, 20...Gas supply port, 21...Gas discharge port, 22...Rotating device, 23
... Feeding device, 24... Cathode, 25... Anode, 2
6... Working gas. Applicant's representative Patent attorney Takehiko Suzue ■

Claims (1)

[Claims] (1) A plasma gun that melts a suspended melting material and the end of this melting material to form droplets of molten metal, and a disk placed at a position where the droplets formed by this plasma gun fall. A metal powder manufacturing apparatus characterized in that a chamber filled with cooling gas is provided with: and a rotating means for rotating the disk to scatter and cool the falling droplets to form a powder.