JP2002129209A - Atomizing nozzle device for metal powder manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device with which metal powder having narrow particle diameter distribution (particle size distribution) of molten metal formed into powder can efficiently be manufactured. SOLUTION: In the atomizing nozzle device for metal powder manufacture, slit shaped nozzles each forming a bar shaped spray form having a focus with a distance shorter than the distance from the base of a conical spray form to the virtual apex are provided at even intervals at the outside of a ring nozzle forming the conical spray form and surrounding a molten metal stream flowing down, so as to divide the molten metal stream into 2-4 mmϕ.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray nozzle device for producing metal powder in a gas atomization method.

[0002]

2. Description of the Related Art In a gas atomization method known as one of the methods for producing metal powder, a gas injected from a nozzle is monotonously spread. This is because the energy of the gas rapidly drops due to adiabatic expansion at the moment when the gas, which is a compressible fluid, comes out of the nozzle. Therefore, it is difficult to efficiently obtain fine metal powder by the gas atomization method, and the obtained metal powder has a wide range of particle size distribution (hereinafter, referred to as particle size distribution). Further, since the injected gas easily involves the atmospheric gas, the gas atomization method has a problem of blowing up the molten metal. Various improvements have conventionally been made to solve these problems.

[0003] For example, a metal melt is pulverized by a jet discharged from an atomizing fluid jet, and a lower jet is provided below the jet. (Japanese Patent Laid-Open No. 1-162704) or by changing the horizontal distance of a plurality of jets at the same distance from the central axis of the molten metal stream and the same horizontal plane so as to form the same angle. A method of disposing the powder and pulverizing the molten metal
-219110).

[0004] However, the above prior art also has the following disadvantages. The energy of the injected gas acts on the outer periphery of the molten metal stream, but the gas energy does not act sufficiently near the center of the molten metal stream, so the particle size distribution of the powdered molten metal A phenomenon occurs in which the width of the pattern widens.
The phenomenon is that the width of the particle size distribution is widened in the fine powder region when the pressure of the injected gas becomes high. Further, when the pressure of the injected gas is reduced, the width of the particle size distribution in the coarse powder region is widened.

That is, in the prior art, since the particle size distribution of the powdered molten metal is wide, unless a large amount of metal is dissolved and atomized, a metal powder having a required particle size cannot be obtained. As a method of solving the above-mentioned drawbacks of the prior art, the metal melt flow is made fine. That is, it has been known that a uniform powder can be obtained by flowing the molten metal little by little. However, this method has a disadvantage that mass production cannot be performed.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the disadvantages of the prior art and to provide an apparatus capable of efficiently producing a metal powder having a narrow particle size distribution.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention divides a molten metal stream into 2 to 4 mmφ outside a ring nozzle forming a conical spray foam surrounding the flowing molten metal stream. A spray nozzle device for producing metal powder, wherein hole nozzles for forming a rod-shaped spray foam having a focal point shorter than a distance from a bottom surface of a conical spray foam to a virtual apex are provided at equal intervals for this purpose. It is.

In the spray nozzle apparatus for producing metal powder of the present invention, the energy of the injected gas acts on the outer peripheral portion of the molten metal stream, which is a drawback of the prior art. In order to solve the problem that the gas energy does not act sufficiently,
The metal melt flow is made thin by providing a hole-shaped nozzle that forms a rod-shaped spray foam having a focal point that is shorter than the distance from the bottom surface of the conical spray foam to the virtual vertex so that it can be divided into mmφ. For this reason, the more uniform gas injection energy acts sufficiently to the center of each of the divided molten metal flows, and coarsening can be prevented.

That is, the gas sprayed from the hole nozzles forming the rod-shaped spray foam and the gas sprayed by the conical spray foam are provided at equal intervals so that the molten metal stream can be divided into 2 to 4 mmφ. With a larger area, the center of the molten metal flow between the hole-shaped nozzles forming the rod-shaped spray foam provided as necessary and the center of the molten metal flow from the bottom of the conical spray foam to the virtual vertex. A rod-shaped spray foam formed by a plurality of rod-shaped spray foams having a focal length longer than a distance can make the energy of the injection gas more uniformly act on the metal melt, and the powdered metal melt Of the particle size distribution can be narrowed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a spray nozzle apparatus for producing metal powder according to the present invention will be described in detail with reference to the drawings. FIG.
2 and FIG. 2 are a conceptual view of a cross section of a spray nozzle device for producing metal powder of the present invention and a spray foam formed and a bottom view of a spray nozzle portion. However, the virtual focus of the spray form does not actually exist.

The hole nozzle for forming the rod-shaped spray foam is provided so that the molten metal flow can be divided into 2 to 4 mmφ. When the divided molten metal flow is 4 mmφ or more, the energy of the injection gas is reduced. Can not be sufficiently actuated up to the center portion, and the amount of generated coarse powder increases. Also, when trying to divide the molten metal stream to 2 mmφ or less, most of the molten metal is powdered by the injected gas. As a result, the energy of the gas injected to the center of the molten metal does not act uniformly, and the gas atomizing nozzle having a single gas injection angle with respect to the molten metal, as described in the related art, has a particle size distribution that is not much different from that of the gas atomizing nozzle. Only a metal powder having a width of

The hole-shaped nozzle for forming the rod-shaped spray foam is provided outside the ring nozzle for forming the cone-shaped spray foam, as shown in FIG. 1 by the rod-shaped spray foam (6) injected from (2). The metal melt is divided and pulverized. Then, the metal melt not broken by (6) is pulverized with a conical spray foam (5) sprayed from (1), thereby preventing coarsening of the metal powder. Further, the spray foam of (5) also serves to prevent the metal melt from partially blowing up.

However, as shown in FIG. 5, when the hole nozzle (2) is provided inside the ring nozzle (1), the molten metal is divided by the rod-shaped jet foam (6) injected from (2). However, a part of the molten metal, which is a disadvantage of the gas atomization method, may blow up, which is not preferable. When this blow-up occurs, only a small amount of the molten metal can be powdered with the conical spray foam of (5),
The amount of generated coarse powder as in the prior art is increased.

Similarly, when a hole-shaped nozzle for forming a rod-shaped spray foam is provided inside a ring nozzle for forming a conical spray foam, the diameter of the ring nozzle becomes large, and the gas injection angle from the ring nozzle is not changed. In addition, the focal length of the conical spray foam formed by the gas to be injected becomes longer, the metal melt cannot be sufficiently pulverized, and the amount of coarse powder generated increases. If the injection angle is changed to shorten the focal length of the conical spray foam, the angle difference from the rod-shaped spray foam injected from the hole-shaped nozzle is reduced, and the molten metal cannot be divided.

Further, the focal point of the hole-shaped nozzle forming the hole-shaped nozzle forming the rod-shaped spray foam may be arranged at a shorter distance than the distance from the bottom of the conical spray foam to the virtual vertex. If it is arranged at the focal point, the molten metal stream cannot be divided, but is captured by a conical spray foam as a thick molten stream and pulverized, so that the amount of coarse powder generated as in the prior art increases.

As shown in FIGS. 1 and 2, if necessary, a hole-shaped nozzle for forming a rod-shaped spray foam provided so that the molten metal stream can be divided into 2 to 4 mmφ.
(2) Between the center of the molten metal flow, a plurality of rod-shaped spray foam having a focal point longer than the distance from the bottom of the conical spray foam to the imaginary vertex of the conical spray foam (7) is provided because a hole-shaped nozzle (2) for forming a rod-shaped spray foam and a ring nozzle (1) for forming a conical-shaped spray foam provided so that the molten metal flow can be divided into 2 to 4 mmφ first. This is because the gas (5), (6) injected from the nozzle may cause a part of the molten metal to be coarsened without being powdered, which is advantageous in preventing this.

The gas (8) injected from the plurality of hole-shaped nozzles (7) causes the gas (5),
Since the gap between (6) and (8) is reduced, the gas can be more uniformly applied to the molten metal stream. This makes it possible to divide the molten metal stream more uniformly, so that the molten metal can be uniformly powdered.

FIG. 3 is a conceptual diagram showing the state of the molten metal when atomized by the spray nozzle device for producing metal powder of the present invention. The molten metal of (A) is extruded by a jet jet foam (9) in which a conical spray foam and a rod-shaped spray foam are synthesized, as shown in (B) and (C), to a portion where (9) does not hit. As a result, the molten metal is completely divided as shown in (D) and powdered as shown in (E). If further pulverization is desired, by providing a plurality of hole-shaped nozzles, the gas injected from these hole-shaped nozzles can be completely pulverized as shown by (F).

FIG. 6 and FIG. 7 are conceptual views of a cross section showing the state of powdering of the prior art molten metal stream and the magnitude of the vertical component of the gas injected from the prior art metal powder apparatus with respect to the molten metal stream. FIG. As can be seen from the figure, the energy of the injected gas acts only on the outer peripheral portion of the molten metal flow, and the energy does not sufficiently act near the central portion of the molten metal flow. For this reason, a phenomenon occurs in which the width of the distribution of the particle size of the powdered molten metal is widened.

However, when the spray nozzle device for producing metal powder of the present invention is used, a conical spray foam (5) sprayed from (1) shown in FIG. 1 and a rod-shaped spray foam (6) sprayed from (2) are used. As shown in FIG. 4, the component in the vertical direction with respect to the molten metal flow of the spray foam synthesized with
The vertical reporting component (9) to the molten metal flow of the injection jet foam synthesized with (6) is divided by the molten metal, so that the gas injection energy acts on the center of the molten metal. It became possible to powder the central part. Further, in the vertical component (10) of the gas injected from the (7) provided in the case with respect to the molten metal flow, the gap between the gas and the molten metal flow is reduced, so that the molten metal can be further powdered. Thereby, the object of the present invention of narrowing the width of the particle size distribution of the molten metal can be achieved.

[0021]

EXAMPLES / COMPARATIVE EXAMPLE Example 1 (a hole-shaped nozzle (2) for forming a rod-shaped spray foam so that a molten metal stream can be divided into 4 mmφ with a spray nozzle apparatus for producing metal powder of the present invention shown in FIG. 1) 8 are provided at equal intervals) and Comparative Example 1 (FIG. 8).
And the gap between the nozzles is the same as in Example 1; the comparative example 2 (the gap between the nozzles is the same as in Example 1 for the conical nozzle shown in FIG. 5); A device in which a foam-forming nozzle is provided inside a conical spray foam)
A gas atomization of copper at 00 ° C. was performed. Conditions are: melt diameter: 7 mm spray gas: air (injection pressure; 4 kgf / cm ² , injection gas flow rate: 20 m ³ / min) (gas temperature; 20 ° C. before exiting the nozzle)

Example 2 (a hole-shaped nozzle for forming a rod-shaped spray foam so that a molten metal stream can be divided into 2 mmφ with a spray nozzle apparatus for producing metal powder of the present invention shown in FIG. 2)
(2), provided at equal intervals, and further provided between two nozzles (2) provided with two nozzles (7) having a focal point of a longer distance than the conical spray form (1)) and Comparative Example 3 (FIG.
The gas atomization of copper at 1200 ° C. was carried out according to the conical nozzle shown in FIG. Conditions are: melt diameter: 5 mm spray gas: air (injection pressure; 5 kgf / cm ² , injection gas flow rate: 20 m ³ / min) (gas temperature; 20 ° C. before exiting the nozzle)

COMPARATIVE EXAMPLE 4 (Pore-shaped nozzle for forming a bar-shaped spray foam so as to divide a molten metal stream into 1 mmφ with the spray nozzle apparatus for producing metal powder of the present invention shown in FIG. 1)
(2), a device provided at equal intervals) and Comparative Example 5 (conical nozzle shown in FIG. 5, the nozzle gap is the same as Example 3),
Gas atomization of copper at 1200 ° C. was performed. Conditions are: melt diameter: 6 mm spray gas: air (injection pressure; 5 kg / cm ² , injection gas flow rate: 20 m ³ / min) (gas temperature; 20 ° C before exiting the nozzle)

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

As shown in Table 1, Example 1 of the spray nozzle apparatus for producing metal powder of the present invention has a thickness of 75 μm to 150 μm.
The ratio of the powder particle size of m was increased as compared with Comparative Examples 1 and 2, indicating that the width of the particle size distribution was narrowed. As shown in Table 2, Example 2 of the spray nozzle apparatus for producing metal powder of the present invention has a powder particle size larger than 75 μm without increasing powder having a particle size smaller than 45 μm as compared with Comparative Example 3. It indicates that the width of the particle size distribution has been narrowed. As shown in Table 3, the molten metal flow was 1 mm
Comparative Example 4 shows that only powder having a particle size distribution equivalent to that of Comparative Example 5 can be obtained if the particle size is reduced to φ or less.

As can be seen from FIG. 6, in Comparative Examples 1, 3, 4, and 5, the energy of the injected gas acts on the outer peripheral portion of the molten metal stream, but the central portion does not. Since the energy of the injection gas is not sufficiently applied to the gas, the amount of generated coarse powder is large. As in Comparative Example 2, the molten metal flow was 4 m inside the conical spray foam.
Even if a hole-shaped nozzle for forming a rod-shaped spray foam that can be divided into mφ is provided, the width of the particle size distribution is widened due to the phenomenon of blowing up the molten metal which is a problem of the gas atomization method as shown in FIG.

[0029]

As described above in detail, in the production of metal powder by the gas atomization method, since the width of the particle size distribution of the powdered molten metal, which is a disadvantage of the prior art, is wide, a large amount of metal is produced. The problem that the metal powder having the required particle size could not be obtained unless melted and atomized was used to divide the molten metal stream into 2 to 4 mmφ by using the metal powder production spray nozzle device of the present invention. As a result, the width of the particle size distribution of the powdered metal melt can be narrowed, and the metal powder having the desired particle diameter can be stably and efficiently produced.

[0030]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a cross section of a spray nozzle device for producing metal powder of the present invention and a bottom view of a spray nozzle portion. (The same figure
(a) is a conceptual diagram of a section on a GG line of the same figure (b). )

FIG. 2 is a conceptual diagram of a cross section of a spray nozzle device for producing metal powder of the present invention and a bottom view of a spray nozzle portion. (The same figure
(c) is a conceptual diagram of a cross section taken along line HH in (d) of FIG. )

FIG. 3 is a conceptual diagram showing a state of a molten metal when atomized by the spray nozzle device for producing metal powder of the present invention.

FIG. 4 is a conceptual diagram showing the magnitude of a vertical component of a gas injected from a spray nozzle device for producing metal powder of the present invention with respect to a molten metal flow.

FIG. 5 is a hole-shaped nozzle for forming a rod-shaped spray foam.
(2) The ring nozzle that forms the conical spray foam
FIG. 2 is a cross-sectional view of a spray nozzle device for producing metal powder when provided inside (1).

FIG. 6 is a cross-sectional view illustrating a state of pulverization of a molten metal stream according to a conventional technique.

FIG. 7 is a conceptual diagram showing a magnitude of a vertical component of a gas injected from a conventional metal powder manufacturing apparatus with respect to a molten metal flow.

FIG. 8 is a conceptual diagram of a cross section of a conventional apparatus (conical nozzle) for producing metal powder.

[0030]

[Explanation of symbols]

1: Ring nozzle for forming a conical spray foam 2: Hole nozzle for forming a rod-shaped spray foam for dividing a molten metal stream into 2 to 4 mmφ. 3: Molten metal flow 4: Hole through which the metal melt flows 5: Conical spray foam injected from 1: 1 6: Bar-shaped spray foam injected from 2: 7: Form a rod-shaped spray foam provided between 2 if necessary Perforated nozzle 8: Bar-shaped spray foam injected from 8: 7 9: 5 and 6 vertical component to molten metal flow of injected jet foam synthesized from 10: 7 Vertical direction to molten metal flow of injected jet foam injected from 10: 7 Component 11: Divided molten metal stream 12: Pulverized molten metal 13: Powdered molten metal (pulverized) 14: Blowed molten metal stream 15: Gas injected from nozzle 16: Powdered Unmelted metal 17: Vertical component of gas injected from prior art metal powder production equipment with respect to molten metal flow

Claims (2)

[Claims] 1. A distance from the bottom of a conical spray foam to a virtual vertex to divide the molten metal stream into 2 to 4 mmφ outside a ring nozzle forming a conical spray foam surrounding the flowing metal melt flow. A spray nozzle apparatus for producing metal powder, wherein hole-shaped nozzles for forming a rod-shaped spray foam having a focus at a shorter distance are provided at equal intervals. 2. A plurality of nozzles having a focal length longer than a distance from a bottom surface of a conical spray foam to an imaginary vertex with respect to a center of a molten metal flow between hole nozzles forming a rod-shaped spray foam. The spray nozzle device for producing metal powder according to claim 1, further comprising a hole-shaped nozzle for forming the rod-shaped spray foam.