JPH01195207A - Method and apparatus for manufacturing metal particle - Google Patents

Abstract

PURPOSE:To obtain metal particles having high ratio of small size by dropping molten metal drip regulating wt. per one drip on a vibrating plate, dispersing and cooling. CONSTITUTION:By gas injection to the molten metal flow or melting of the metal wire, the metal drip 33 of 0.1-1.5g wt. of one drip is adjusted. This drip 33 is dropped on the bottom plate 22 vibrating the metal particle forming device 20 and dispersed as fine particle-state with vibrating energy and colliding energy at the time of dropping. Then, while forming to globular-shape with the surface tension, the drip is cooled and solidified. The above metal particle forming device 20 is opened at the upper part and the front part, and the bottom plate 22 composing of the material having high heat conductivity is set at lower part of the vibrating box 21, and a jacket 23 for water cooling is arranged at lower face of the bottom plate 22.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is suitable for molding metal particles having a spherical shape or a shape close to it, particularly relatively small-diameter metal particles having a diameter of 0.2 to 2.0 mm. The present invention relates to a manufacturing method and an apparatus for manufacturing the same.

[Conventional technology]

The atomization method is widely used as a method for manufacturing metal particles. In this method, molten metal flows down through pores in a heating furnace, and air or other gas is injected from a nozzle into the flowing molten metal to disperse it into atomized droplets. It is solidified by cooling in a gas atmosphere.

[Problem to be solved by the invention]

In the conventional atomization method, the temperature of the gas atmosphere is lowered to solidify the dispersed droplets, which not only increases the time required for cooling, but also requires large-scale cooling equipment to cool the atmosphere. The disadvantage is that the equipment costs are high because it requires

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing metal particles and an apparatus for producing the same, which eliminates such drawbacks and enables shortening of the cooling time of droplets and downsizing of the cooling device.

[Means to solve the problem]

The method for producing metal particles of the present invention involves dropping metal droplets with a weight of 0.1 to 1.5 g per droplet onto a diaphragm directly or in a dispersed state, thereby absorbing the vibration energy of the diaphragm and the droplets. Dispersed into fine particles by the collision energy of time,
The process involves shaping the dispersed particles into a spherical or nearly spherical shape due to their own surface tension, and solidifying them by removing heat with a diaphragm and cooling with the surrounding atmosphere.

Further, the metal particle manufacturing apparatus of the present invention includes a metal droplet preparation apparatus that produces metal droplets by jetting gas to a molten metal flow or melting a metal wire, and a metal particle forming apparatus disposed below the metal droplet preparation apparatus. The metal particle forming device includes a bottom plate made of a highly thermally conductive material installed at the bottom of a vibration box that is open at the top and the front and suspended so that it can vibrate in the vertical direction, It has a water cooling jacket on the underside of the bottom plate.

Next, the present invention will be explained based on the drawings.

The method of forming and dropping metal droplets is carried out using, for example, a metal droplet preparation apparatus 10 shown in FIG. 1 or 2.

In the method shown in FIG. 1, molten metal 30 charged into a tundish 11 is caused to flow down from the pores 12 as a molten metal stream 31.

Air or other gas is injected into this molten metal flow 31 from a pair of nozzles 13 that intersect with the horizontal plane at an injection angle of θ,
It is caused to fall as droplets 33 dispersed by the collision energy of the gas. The weight of each droplet 33 is 0.1~
The amount can be adjusted to 1.5 g.

In the method shown in FIG. 2, the metal wire 32 is fed out by a feeding device (not shown), and the tip of the metal wire '32 is TIG)-
It is continuously melted by the arc generated from the electrode of the hole 14 and directly falls as a droplet 33. This droplet 33 can be prepared so that the weight per droplet is 0.1 to 1.5 g. Reference numeral 15 in the figure is a ground.

The droplets 33 produced by the metal droplet preparation device 10 described above are shaped into desired metal particles by the metal particle forming device 20 disposed below the metal droplet preparation device 10.

As shown in FIG. 3, the metal particle forming device 20 has a bottom plate 22 made of a highly thermally conductive material (copper, for example) at the bottom of a vibration box 21 whose top and front are open. A water cooling jacket 23 is attached to the lower surface of the bottom plate 22. This vibration box 21 is suspended from a fixed bar 24 via a spring 25, and is vibrated in the vertical direction by a vibrator 26 attached to the top. On the bottom plate 22 of the vibration box 21,
It is desirable to apply a release agent to the upper surface of the layer, and in this way, it is possible to prevent fallen metal droplets from adhering.

Metal droplets 33 falling into the box from the upper opening of the vibration box 21
When the particles collide with the bottom plate 22, they receive the vibration energy of the vibration box 21 and the collision energy, and become fine dispersed particles 34, which are spread on the bottom plate 22. The dispersed particles 34 are formed into a spherical or nearly spherical shape by their own surface tension, and as this spherical formation progresses, the vibration box 21
Dispersed particles 34 rolling on the bottom plate 22 due to vibrations are cooled by the bottom plate 22, which is forcibly cooled by the circulating water of the water cooling jacket 23, and are cooled by the atmosphere inside the vibration box 21, so they solidify and reach their intended purpose. It is formed into metal particles.

The metal particles produced in this way are
2 to the front of the vibration box 21, is discharged to the outside from the front opening end of the vibration box 21, and is collected in a container (not shown).

In this metal particle forming device 20, by changing the falling distance of the metal droplet 33 and the amplitude of the vibration box 21,
Metal particles with different particle size distributions can be formed. The larger the falling distance of the metal droplet 33 and the amplitude of the vibration box 21, the smaller the metal particles can be obtained.

〔Example〕

(1) Example 1 Copper was used as a material for metal droplets, and droplets were prepared using the apparatus shown in FIG. 1 kg of copper is heated and melted in a burner furnace, then charged into a tundish using a spool, and allowed to flow down through the pores of the tundish.The flow rate of the compressed air injected into the flowing molten metal stream is varied in two ways. Dispersed.

The dispersed droplets were all dropped from the same height and cooled on a vibrating bottom plate (cooled by a water cooling jacket) under the same conditions. The preparation conditions and vibration conditions for the two types of droplets mentioned above are as shown in Table 1.

Table 1 The falling distance of a droplet is the vertical height from the intersection of the jet air to the surface of the vibrating box.

The cumulative particle size distribution of copper particles produced under the conditions shown in Table 1 is shown in FIG.

From the results in the same figure, it can be seen that if the falling distance of the droplet and the vibration conditions are the same, a larger amount of particles with smaller diameter can be produced by increasing the flow rate of the jet air to the falling molten metal flow. .

(2) Example 2 Stainless steel, 1llsU302B (18Cr-8Ni
-2Si-Fe) was used as the material for the metal droplets, and the droplets were prepared using the apparatus shown in FIG. stainless steel is 3k
g was melted by induction heating, charged into a tundish using a ladle, and allowed to flow down through the pores of the tundish, and the flow rate of compressed air injected into the falling molten metal stream was varied in two ways to disperse it.

The falling distance of the dispersed droplets and the vibration conditions were both the same as in Example 1.

The preparation conditions and vibration conditions for the above two types of droplets are as shown in Table 2.

Table 2 The falling distance of a droplet is the vertical height from the intersection of the jet air to the surface of the vibrating box.

The cumulative particle size distribution of stainless steel particles produced under the conditions shown in Table 2 is shown in FIG.

Looking at the particle size distribution curve in the figure, it can be seen that the same results as in Example 1 are obtained.

(3) Example 3 Stainless steel 5U3302B was used as the material for the metal droplets.
(18Cr-8Ni-2S 1-Fe) wire
Droplets were prepared by continuous arc melting using the TIG)-chi of the apparatus shown in the figure.

The prepared droplets were cooled by falling directly onto the bottom plate of a vibration box using four different combinations of drop heights and vibration conditions.

The above droplet preparation conditions and the four combination conditions were
Shown in the table.

Table 3: The cumulative particle size distribution of stainless steel particles produced using droplet holes 5 and 6 under conditions where the falling distance of the droplet is the same and the amplitude of the diaphragm is different is as shown in Figure 6. be.

Further, regarding the stainless steel particles produced by the droplet barrier 5 and the hole 6, the relationship between the yield of particles having a predetermined particle size or less and the amplitude of the vibrating box is shown in FIG. 7.

From the results in both figures, when the droplet falling distance is the same,
It can be seen that as the vibration box amplitude increases, the yield of small diameter particles increases.

Droplet N15 under conditions where the vibration box amplitude is the same and the droplet falling distance is different. l1m? The cumulative particle size distribution of the stainless steel particles produced by Magnetic 8 is as shown in FIG.

Moreover, this droplet N15. ! 1m? FIG. 9 shows the relationship between the yield of particles having a predetermined particle size or less and the droplet falling distance for stainless steel particles produced by Magnet 8 and Magnet 5.

From the results in both figures, it can be seen that when the vibration box amplitude is the same, the yield of small-diameter particles increases as the falling distance of the droplet increases.

〔Effect of the invention〕

As explained above, according to the manufacturing method of the present invention, the droplets that have fallen onto the bottom plate of the vibrating box are dispersed into fine particles by the vibration energy of the vibrating box and the collision energy when falling.
During the process of spheroidization, the dispersed particles solidify by removing heat from the vibrating box and cooling by the surrounding atmosphere, making it possible to solidify in a relatively short period of time and to produce metal particles with a large proportion of small diameter particles. Become.

Furthermore, since the metal particle forming apparatus of the present invention is composed of a vibrating box with a water cooling jacket on the bottom plate made of a highly thermally conductive material, it does not require large-scale cooling equipment required for conventional atomization methods. The device is smaller in size and has lower equipment costs than the previous method, making it suitable for mass production of metal particles.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of the metal droplet preparation device of the present invention with a part thereof in cross section, FIG. 2 is a front view showing another example of the metal droplet preparation device of the invention, and FIG. The figure is a perspective view showing an embodiment of the metal particle forming apparatus of the present invention, FIGS. 4 and 5 are cumulative particle size distribution diagrams according to manufacturing examples of the present invention, and FIG. 6 is another manufacturing example of the present invention. FIG. 7 is a graph showing the relationship between yield and amplitude on the particle size side according to the production example of FIG. 6, and FIG. 8 is a cumulative particle size distribution diagram according to still another production example of the present invention. Distribution map, Figure 9 is the 8th
It is a graph showing the relationship between the yield on the particle size side and the droplet falling distance according to the production example shown in the figure. In the figure, 10 is a metal droplet preparation device, 11 is a tundish,
13 is a nozzle, 14 is a TIG)-ch, 20 is a metal particle forming device, 2 is a vibration box, 22 is a bottom plate, 23 is a water cooling jacket, 26 is a vibrator, 30 is a molten metal, 31 is a molten metal flow, 32 3 is a metal wire, 33 is a metal droplet, and 34 is a dispersed particle. Patent Applicant Nippon Yakin Kogyo Co., Ltd. Representative Patent Attorney Tetsuya Mori Patent Attorney Masaru Shimizu Representative Patent Attorney Tadashi Shimizu chanting (mm)

Claims (2)

[Claims] (1) Metal droplets with a weight of 0.1 to 1.5 g per droplet are dropped directly or in a dispersed state onto a diaphragm, and the vibration energy of the diaphragm and the collision energy at the time of the drop are A method for producing metal particles, which comprises dispersing them into granules, shaping the dispersed particles into a spherical or nearly spherical shape by their own surface tension, and solidifying them by removing heat with a diaphragm and cooling with the surrounding atmosphere. (2) comprising a metal droplet preparation device that produces metal droplets by jetting gas to a molten metal flow or melting a metal wire; and a metal particle forming device disposed below the metal droplet preparation device; The device has a bottom plate made of a highly thermally conductive material installed at the bottom of a vibration box that is open at the top and front and suspended so that it can vibrate in the vertical direction, and a water cooling jacket is installed on the bottom of the bottom plate. 1. An apparatus for producing metal particles, characterized by comprising: