JPS62253706A - Apparatus for producing metal power by impact atomization - Google Patents

Abstract

PURPOSE:To efficiently grind a molten metal and to reduce the size of a powder capturing vessel by installing two pieces of strinking impellers which rotate at a high speed in a horizontal direction in such a manner that strinking vanes having a specific helix angle face each other and generating downward air flow between the strinking impellers. CONSTITUTION:For example, the strinking vanes 5 or the peripheral edges 7 thereof are inclined at an angle beta with a revolving shaft 14 in such a manner that the rotating loci of the extension lines 8 thereof form a circular conical shape. The front faces 6 of the vanes 5 are twisted by the helix angle alpha(5-85 deg.) with the shaft 14 in order to rotate the bases 13 of the vanes 5 with a delay in phase relative to the top surfaces 11. The helical gear-shaped 1st strinking impeller 4 and the similar 2nd strinking impeller 20 are thus disposed in such a manner that the strinking vanes 5, 21 thereof face each other. Such impellers are rotated and the molten metal flow 2 is poured to the peripheral edges 7. The molten metal flow 2 is entrained into the downward air flow and is dropped by the vanes 5, 21 having vent holes 18, by which the molten metal is pulverized and quickly cooled. The pulverized metal is captured by passing a vent part 25 between stationary bases 24 and 24.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a metal powder manufacturing apparatus for impact-pulverizing and atomizing molten metal in a downward airflow.

[Conventional technology]

Conventionally, equipment for directly producing powder from molten metal is
A liquid atomization device that uses a high-speed liquid such as water or oil as a spray medium, and N2. Gas atomization equipment that uses high-speed gas such as Ar, spray atomization equipment that atomizes molten metal with gas, vacuum atomization equipment that releases occluded gas in molten metal into a vacuum and sprays it, and high-speed rotating bodies such as disks and bowl-shaped drums. There are various devices such as a centrifugal atomization device that drops molten metal onto the inner surface of the metal and scatters it using centrifugal force.

On the other hand, in recent years, for powder metallurgy, metal catalysts, paint pigments,
There is a need for a low-cost apparatus for producing rapidly solidified, highly clean metal powder with a fine structure in which amorphous or alloying elements are dissolved in a highly supersaturated solid solution as a raw material powder for magnetic materials and the like.

However, the metal powder manufacturing apparatus described above cannot satisfy these requirements.

That is, liquid contamination occurs in liquid atomizing devices. In gas atomization equipment, the average particle size is 100-30
The cooling rate is approximately 0.01 Lm, and the cooling rate is also required to be 102~b. Spray atomization devices are difficult to apply to high-melting point metals due to the material of the spray nozzle. In the vacuum atomization device, the cooling rate is 102℃/s
The types of storage gas and molten metal are limited by about ec. In a centrifugal atomization device, slipping occurs between the rotating disk such as a disk or a bowl-shaped drum and the molten metal, and only powder with an average particle size of about 11,001 L is obtained. can only be provided in the vertical direction or in a direction slightly tilted from the vertical direction, making it difficult to increase the size and making it difficult to obtain very fine powder.

A device that crushes and sprays the flow of molten metal by applying the barrier force of a gear-shaped or impeller-shaped impeller with protrusions and recesses, or a rod- or hammer-shaped striking arm or impeller, etc. In other words, according to the rotary impact spraying device, the impact energy given to the molten metal is large, and since the device can have a rotating shaft in the horizontal direction as well as the vertical direction, it is possible to increase the size and exceed 50 m/see. It can be pulverized and sprayed at circumferential speed. For this reason, it is possible to further atomize the particles, so 105
A cooling rate of about 10"C/sec can be achieved.

As this rotary impact spray device, there are two types of rotary impact spray devices, which are B, I, and I
,O,S,Report No.,706°No.,122
There are P, G' (rotating disk) devices described in No. 3, and in recent years Powder Metal, I rlt,
.

Vol, 11.1979. PI3, Japanese Patent Publication No. 55-128
507, JP 58-153707, JP 58-197206, JP 60-24304
No. 60-121206. Further, as an example of an impeller configured with two or more impellers provided with striking blades, there is Japanese Patent Application Laid-Open No. 60-228603.

[Problem that the invention seeks to solve]

The main parameters when producing metal powder using a rotary impact atomizer are the diameter of the impeller, the shape of the impeller, the weight of the impeller, and the rotational speed and circumferential speed of the impeller.

There are issues such as the material of the striking blades, but there are also the following problems.

(1) Rotation of the impeller causes centrifugal force to act in the radial direction, creating airflow. JP-A-58-197206, JP-A-60-121206 and JP-A-60-2286
With the exception of No. 03, the known rotary impact spraying devices include:
Since this air flow is discharged toward the injection flow of molten metal, the molten metal is
There is a problem that 41%S of books are lost.

In particular, this is a serious problem when the impeller diameter or rotational speed is increased, or when pre-spraying using other airflows is used in advance of impact spraying. Therefore, in these known rotary impact spray devices, the generation of airflow is suppressed by minimizing the length and depth of the striking vanes and between the striking vanes, or the length of the supporting arm of the striking vanes, or by using a vertical rotating shaft. The impeller is rotated horizontally to emit airflow in the radial direction, which is the horizontal direction, while molten metal is injected from the vertical direction to avoid scattering due to the airflow. In such a device, it is not possible to impact crush the molten metal flow at the maximum diameter position of one impeller.

(2) As a device in which a striking impeller is installed in a vacuum to prevent the molten metal injection flow from scattering due to the discharged airflow accompanying rotation, Japanese Patent Application Laid-Open Nos. 58-197206 and 60-60
There is a publication No.-228603. However, these devices do not allow for gas cooling of the crushed particles.

(3) In the above-mentioned known rotary impact spraying device, the crushed droplets are scattered over a wide range, and most of them are scattered in the vertical direction where the molten metal is injected. Not only do they adhere to the bottom of the chamber and disturb the injection flow and reduce the powder recovery yield, but the detached deposits also damage the striking blades. Further, the scattered droplets in this direction of rotation are coarse particles.

(4) Except for Japanese Unexamined Patent Publication No. 60-228603, the above-mentioned known rotary impact spraying devices are composed of one percussion impeller having percussion vanes. Therefore, once the molten metal droplets are impact-pulverized by the striking blades of the rotating striking impeller,
The droplets are scattered outside the percussion impeller in a molten state, and even though they are still in a molten state, they are not subjected to impact pulverization by the percussion blades of the percussion impeller again, and the droplets remain in a molten state. Because they fly, large powder collection vessels are required to collect them.

(5) FIG. 4 shows a conceptual diagram of a situation in which the downward airflow generated by the rotation of the percussion impeller is reflected by the fixed base of the percussion impeller and scatters the falling flow of molten metal.

To rotate the striking blade horizontally at high speed.

It is necessary to install the rotation axis in the vertical direction. For this purpose, as shown in FIG.
A structure in which the rotary shaft 14 is vertically disposed, the impact impeller 4 is disposed above the rotary bearing 23, and the rotary power source 27 is disposed below the fixed base 24 is convenient for the configuration of the device, and the length of the rotary shaft 14 is The shorter the length, the more advantageous it is from a mechanical and dynamic point of view, but the fixed base 24 reflects the downward airflow 16 between the striking impellers 4 and blows out the airflow 16 in a horizontal direction, scattering the molten metal injection flow 2. This causes a problem.

Note that in the case of a suspension type structure in which the rotating power source 27 is placed at the top and the rotating bearing 23, rotating shaft 14, and striking impeller 4 are sequentially placed at the bottom, the downward airflow 16 is reflected and the molten metal is injected. Although it is sufficient to provide a sufficient space so as not to disturb the flow 2, the configuration of the molten metal supply section 1 becomes difficult because the rotary power source 27 is provided above the striking blades 5.

The purpose of the present invention is to provide a metal powder manufacturing apparatus that solves these problems, and includes two striking impellers provided with striking vanes, the rotating shafts of which are arranged vertically so that the striking vanes face each other. A device in which the blowing impellers are rotated horizontally to generate a downward airflow between the blowing impellers, molten metal is effectively crushed between the impellers, and the powder collection tank is miniaturized. The purpose is to provide

[Means for solving problems]

The present invention solves the above-mentioned problems and is applied to an apparatus for producing metal powder by impact atomization, and basically includes: A) generating a downward airflow and treating the falling flow of molten metal therein; do.

B) The falling flow of molten metal is obliquely cut by an impeller that is inclined to the falling flow.

C) Providing a second striking blade for re-grinding to further increase the crushing effect.

I decided to do so.

The problem of the airflow caused by the rotating percussion vanes scattering the molten metal injection stream can be solved by directing the airflow produced by the percussion vanes downwards by twisting the percussion vanes.

In addition, even if the blowing impeller is used to create a downward airflow, the fixing base of the rotating bearing below the blowing impeller disturbs the downward airflow and blows out the airflow in the horizontal direction. By providing this section, the airflow in the molten metal falling space and the impact crushing space can be directed downward.

As a rotary impact spraying means, it is most efficient to impact and crush the molten metal flow horizontally from the side in front of a rotating impact blade.

However, the higher the rotation speed of such a striking blade, the more opportunities there are to crush and spray the molten metal on the upper surface and front upper side of the striking blade facing the molten metal injection flow.
A problem arises in that the molten metal is scattered in the direction in which the molten metal is injected, and the scattered droplets are coarse particles. Therefore, in the present invention, the falling flow of molten metal is obliquely cut. That is, the outer periphery of the striking root is inclined in the axial direction, and the striking vane is shaped like a helical bevel with a twist angle relative to the axis of rotation, and a falling flow of molten metal is supplied to the side surface of the outer edge of the striking blade. did. As a result, scattering in the injection direction is eliminated, and the scattering direction of the crushed and sprayed droplets can be directed downward. Furthermore, the crushing efficiency was increased by re-pulverizing the powder using a second rotating blowing blade installed in parallel with the blowing blade.

In addition, in order to quickly release the suction air, a vent hole was provided in the striking blade for the suction air to pass through.

[Effect]

According to the present invention, the injection flow of molten metal is pulverized by impact without being discharged by the rotation of the striking blade or being scattered by the air current. Moreover, it is possible to prevent the impact-pulverized droplets from scattering in the vertical direction or in the injection direction of the molten metal. Furthermore, since it is re-pulverized using two impellers, atomization and gas cooling can be achieved.

In addition, by providing ventilation holes in the striking blades, the suction airflow passes through quickly, which not only improves the impact crushing efficiency, but also promotes airflow cooling of the striking blades and reduces wind pressure (Jjl loss) on the striking blades. It is possible to reduce the output of the rotational power source.

〔Example〕

FIG. 3 shows an example of a striking impeller 4 used in carrying out the present invention, in which (a) is a plan view and (b) is a perspective view. The striking vane 5 projects from the striking impeller 4, and includes a front surface 6 of the striking vane,
It is composed of a peripheral edge 7 of the striking blade, a back surface 10 of the striking blade, an upper surface 11 of the striking blade, and a bottom surface 13 of the striking blade.

Further, the striking blade 5 is provided with a ventilation hole 18. The periphery of the percussion blade is arranged such that when the percussion blade 5 is rotated, the rotation locus of the perforation 7 of the percussion blade 5 or the extension line 8 of the perforation of the percussion blade substantially forms a conical shape. The portion 7 is tilted at an arbitrary angle with respect to the rotating shaft 14. Hereinafter, this angle will be referred to as an inclination angle β. The inclination angle β approximately corresponds to a complementary angle of 1/2 of the apex angle of the virtual cone.

Further, the impeller is constructed by twisting the bottom surface 13 of the striking vane 5 so that its rotational phase is delayed. A specific example of the striking blade 5 is that when the striking blade 5 is rotated, the peripheral edge 7 of the striking blade or the extension line 8 of the peripheral edge of the striking blade is substantially conical; It has one longitudinal direction when projected onto a plane perpendicular to a perpendicular line 15 drawn from the center 9 toward the rotation axis 14, and this longitudinal direction is twisted in a helical shape with respect to the rotation axis 14. The bottom surface 13 of the striking blade is the top surface 1 of the striking blade.
It is configured so that it rotates with a phase delay relative to 1.

The angle at which the striking blade 5 is twisted in a helical shape with respect to the rotation axis is called a twist angle α.

As described above, the peripheral edge 7 of the striking blade is inclined so that the peripheral edge 7 of the striking blade or the rotation locus of the extension line of the peripheral edge 7 of the striking blade forms a conical shape, and the bottom surface 13 of the striking blade is tilted. The front surface 6 of the striking vane is twisted so that the striking vane 5 rotates with a phase delay relative to the upper surface 11 of the striking vane.
By providing this, the striking impeller 4 sucks in airflow from the rotating impeller 7 with a leading phase, and releases the airflow substantially downward in the direction of the rotating shaft 14 from the bottom surface 13 of the striking impeller rotating with a delayed phase. Therefore, by injecting the molten metal into the peripheral edge part 7 of the striking blade, the molten metal injection flow 2 coming on the suction airflow can be effectively obliquely cut and pulverized and sprayed by the peripheral edge part 7 of the rotating striking blade. At this time, the angle at which the molten metal injection shaft 3 is incident on the peripheral edge 7 of the striking blade is θ
If this is the case, the droplets crushed and sprayed by the peripheral edge 7 of the striking blade are scattered in a concentric conical shape around 62M in the rotational direction of the peripheral edge 7 of the striking blade with a reflection angle θa symmetrical to the incident angle 0.

This not only reduces the scattering of droplets in the vertical direction or in the direction of the injection axis of the molten metal, but also completely prevents it.

The angle of incidence 0 is not limited.Therefore, there is no need to limit the angle of inclination β of the striking blade 5, which is substantially complementary to the angle of incidence θ.Also, the peripheral edge 7 of the striking blade 5 is not limited to the front side as shown in FIG. If it is chamfered so that the radius of rotation becomes shorter toward the back, or if it is formed into a thinner shape in the shape of a thin line, it can be crushed and sprayed on the outer circumferential surface. This can be avoided and pulverization can be performed only by the diagonal cutting action.

Note that the shape of the peripheral edge 7 of the striking blade does not necessarily have to be linear, and may be somewhat uneven, or may be arched or arcuate.2 In short, the peripheral edge 7 of the striking blade or its It suffices if the rotational locus of the approximate extension line is approximately conical. 'Furthermore, when the torsion angle α of the striking blade 5 is less than 5 degrees, airflow is released in the radial direction of the striking blade due to the action of centrifugal force. , the molten metal injection flow 2 is scattered in the space above the virtual rotating cone forming surface. On the other hand, if the twist angle α exceeds 85 degrees, the metal particles will be crushed exclusively at the peripheral edge 7 of the striking blade or the back surface 10 of the striking blade, and the crushed metal particles will become coarse.

Therefore, the front surface 6 of the striking blade or the peripheral edge 7 of the striking blade
In order to make a more efficient horizontal impact, the twist angle α should be set between 5 and 8.
The range is 5 degrees.

FIG. 1 is a perspective view of the main part of an embodiment of the present invention in which a first striking impeller 4 and a second striking impeller 20 are arranged so that their striking vanes 5.21 face each other. .

Two percussion impellers 4.20 are used, the percussion blades 5 as described above having an angle of inclination β and a torsion angle α, the peripheral edge 7 of the percussion blade 5 or the extension of the peripheral edge 7 of the percussion blade 5. The rotation locus of the outer periphery of the first striking impeller 4 is substantially conical, and the rotation locus of the outer periphery of the second striking impeller 21 is cylindrical, and the rotation locus of the outer periphery of the line is substantially conical. 2nd with twist angle
A striking impeller 20 is used, and the circumferential edge of the striking impeller of the first striking impeller 4 and the circumferential edge of the striking impeller of the second striking impeller 20 are arranged so as to face each other, and are arranged in the same direction or in opposite directions. Rotate to

A ventilation portion 25 is provided on the fixed base 24 of the rotary bearing 23 of these two impact impellers. This ventilation part 25 is provided on the fixed base 24 in the downward extension area of the molten metal injection shaft 3, and is made large enough to obtain the downward airflow 16 to the lower part of the fixed base 24.

Figure 2 shows the spray tank 26, the impact impellers 4 and 20, and the rotating bearing 2.
3. The main parts of the device of the present invention are shown, which are provided with a ventilation section 25 and are constructed of a fixed base 24 of a rotary bearing 23. CFL) in FIG. 1 is a plan view, and FIG. 1B is a side cross-sectional layout diagram.

〔Effect of the invention〕

Since the metal powder manufacturing apparatus of the present invention is configured as described above, rapid cooling through atomization creates a special structure such as an amorphous metal powder or a fine structure containing supersaturated solid solutions of alloying elements. High quality metal powder can be produced.

In addition, by providing a ventilation section in the fixed base of the one-rotation bearing through which downward airflow passes, the periphery of the striking blade is inclined so that it forms an almost conical shape, and the blade falls along with the downward airflow. The molten metal injected flow is subjected to diagonal cut impact pulverization to control the scattering direction of the pulverized droplets, and the droplets can be efficiently collided with the striking blades of the second striking impeller provided oppositely. Therefore, further atomization can be achieved. Furthermore, by providing a through-hole in the striking blade, airflow cooling can be promoted in addition to water cooling, and wind damage can be reduced, making it possible to increase the size of equipment, reduce power, and mass-produce powder. Effects such as

[Brief explanation of drawings]

FIG. 1 is a perspective view of the main parts of an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, FIG. This is a striking impeller used in the example, in which (a) is a plan view, (b) is a perspective view, and FIG. 4 is a conceptual diagram of the state of scattering of falling molten metal. 1... Molten metal supply section 2... Molten metal injection flow 3... Molten metal injection shaft 4... Strike impeller 5... Strike vane 6... Front surface 7 of striking vane... - Peripheral edge part 8 of the striking blade... Extension line 9 of the peripheral edge part of the striking blade... Center 10 of the peripheral edge part of the striking blade... Back surface 11 of the striking blade... E-face 12 of the striking blade... Front upper side of the striking blade 13... Bottom surface of the striking blade 14... Rotating shaft 15... Perpendicular line drawn from the center of the outer surface of the striking blade to the rotating shaft 16... Air flow 18... Ventilation hole 20.・・・
Second batting impeller 21...Second batting impeller 23...Rotating bearing 24...Fixing base 25...
Ventilation part 26... Spray tank 27... Rotating power source α... Twisting angle β... Inclination angle θ... Incident angle of molten metal

Claims (1)

[Scope of Claims] 1. An apparatus for producing metal powder by impact atomization, comprising: a first impact impeller that rotates at high speed around a rotating shaft; a helical bevel-shaped first striking impeller having a twist angle of 5 to 85 degrees; a second striking impeller that is arranged in parallel with the first striking impeller and rotates at high speed around a rotation axis; a helical bevel-shaped second striking vane protruding from the outer periphery of the second striking impeller and having a helical angle of 5 to 85 degrees with respect to the rotation axis; and the first and second striking vanes. A fixed stand for rotary bearings that rotatably supports each rotating shaft of the car, a spray tank on which the fixed stand is mounted, and a molten metal supply unit that supplies a falling stream of molten metal to the peripheral edge of the first striking blade. The first and second striking blades are provided with ventilation holes;
An apparatus for producing metal powder by impact atomization, characterized in that a ventilation section is provided between each of the fixing tables.