Metal powder manufacturing apparatus, gas injector and can device thereof

文档序号：1342743 发布日期：2020-07-17 浏览：14次中文

阅读说明：本技术 金属粉末制造装置及其气体喷射器以及罐器 (Metal powder manufacturing apparatus, gas injector and can device thereof ) 是由芝山隆史江口滋信王玉艇今野晋也于 2018-12-07 设计创作，主要内容包括：金属粉末制造装置具备喷雾槽(4)、向喷雾槽(4)内对熔融金属进行液体喷雾的多个喷雾喷嘴(20A、20B)。多个喷雾喷嘴(20A、20B)分别具有使熔融金属向喷雾槽(4)内流下的熔融金属喷嘴(11A、11B)、在熔融金属喷嘴的周围配置多个且具有用于使气体流体与从熔融金属喷嘴流下的熔融金属碰撞的气体喷射孔的气体喷射喷嘴(2A、2B)。(The metal powder production device is provided with a spray tank (4), and a plurality of spray nozzles (20A, 20B) for spraying a liquid onto a molten metal in the spray tank (4). The plurality of spray nozzles (20A, 20B) each have a molten metal nozzle (11A, 11B) for flowing molten metal into the spray trough (4), and a plurality of gas injection nozzles (2A, 2B) arranged around the molten metal nozzle and having gas injection holes for causing the gas flow to collide with the molten metal flowing down from the molten metal nozzle.)

1. A metal powder manufacturing apparatus is characterized in that,

the disclosed device is provided with:

a spray tank;

a plurality of spray nozzles for spraying molten metal into the spray tank,

the plurality of spray nozzles each include a molten metal nozzle for directing the molten metal to flow down into the spray groove, and a gas injection nozzle having a plurality of injection holes arranged around the molten metal nozzle for causing a gas flow to collide with the molten metal flowing down from the molten metal nozzle.

2. The metal powder manufacturing apparatus according to claim 1,

comprises a tank part for storing molten metal and a gas injector arranged below the tank part,

the molten metal nozzle is provided downward from the bottom of the tank portion,

the gas injector has a plurality of molten metal nozzle insertion holes and a gas flow path for forming a gas flow around each of the plurality of molten metal nozzle insertion holes,

the injection hole is formed in a bottom surface of the gas injector and around an opening end of each of the plurality of molten metal nozzle insertion holes.

3. The metal powder manufacturing apparatus according to claim 1,

the gas jet apparatus further includes a sealed gas jet nozzle which is provided between two adjacent spray nozzles among the plurality of spray nozzles, and which injects a gas fluid to form a jet for suppressing collision between molten metals discharged from the two spray nozzles.

4. The metal powder manufacturing apparatus according to claim 3,

the sealing gas jet nozzle has a plurality of holes for jetting the gas fluid,

the plurality of holes are linearly arranged between the two spray nozzles.

5. The metal powder manufacturing apparatus according to claim 3,

the sealing gas jet nozzles are slits for jetting gas fluid respectively,

the gap is disposed between the two spray nozzles.

6. The metal powder manufacturing apparatus according to any one of claims 1 to 5,

in at least one of the plurality of spray nozzles, a focal point of the gas fluid injected from the plurality of gas injection nozzles is located in a flow-down region of the molten metal flowing down from the molten metal nozzle, and a central axis of the molten metal nozzle is located closer to an inner side surface of the spray groove than a center of a circle formed by injection holes of the plurality of gas injection nozzles in a range where the molten metal nozzle does not overlap with the plurality of gas injection nozzles.

7. The metal powder manufacturing apparatus according to claim 1,

the plurality of spray nozzles are different in spray conditions.

8. The metal powder manufacturing apparatus according to claim 7,

the spraying conditions in the plurality of spraying nozzles are different depending on at least one of the spraying pressure of the gas fluid sprayed from the plurality of gas spraying nozzles, the angle of the spray holes in the plurality of gas spraying nozzles, the diameter of the spray holes in the plurality of gas spraying nozzles, the number of spray holes in the plurality of gas spraying nozzles, the minimum hole diameter of the molten metal nozzle, and the shape of the tip of the molten metal nozzle.

9. A gas injector, which is a gas injector of a metal powder manufacturing apparatus, characterized in that,

has a plurality of molten metal nozzle insertion holes into which molten metal nozzles to be flown down are inserted,

the disclosed device is provided with:

a gas flow path for forming a gas flow around each of the plurality of molten metal nozzle insertion holes; and

a gas injection nozzle provided in each of the plurality of molten metal nozzle insertion holes and injecting a gas in the gas flow path from an opening end of the molten metal nozzle insertion hole to an outside of the gas injector,

the gas injection nozzle is formed with a plurality of injection holes formed in a bottom surface of the gas injector and around an opening end of the molten metal nozzle insertion hole.

10. A can body, which is a can body of a metal powder manufacturing apparatus, characterized in that,

the disclosed device is provided with:

a tank portion for storing molten metal; and

a plurality of molten metal nozzles provided downward from the bottom of the tank portion and forming a molten metal flow path through which the molten metal flows downward from the bottom of the tank portion,

the molten metal nozzle is inserted into the molten metal nozzle insertion hole of the gas injector according to claim 9.

11. The gas injector of claim 9,

the gas injection nozzle provided in each of the plurality of molten metal nozzle insertion holes includes a gas injection nozzle in which at least one of injection pressure of the gas fluid, angle of the injection hole, diameter of the injection hole, and number of the injection holes is different from the other gas injection nozzles.

12. The gas injector of claim 9,

the gas injector includes, on a bottom surface thereof, a seal gas spouting nozzle provided between two adjacent molten metal nozzle insertion holes among the plurality of molten metal nozzle insertion holes, and spouting a gas fluid to form a spouting gas for suppressing collision between molten metals flowing down from the plurality of molten metal nozzles.

Technical Field

The present invention relates to a metal powder production apparatus for producing fine particulate metal (metal powder) by causing a high-pressure gas fluid to collide with molten metal flowing down from a molten metal nozzle, and a gas injector and a tank therefor.

Background

As a method for producing a fine-particle metal (metal powder) from a molten metal, there is an atomization method including a gas atomization method and a water atomization method. The gas atomization method is a method in which a molten metal flows down from a molten metal nozzle located at the lower part of a melting tank for storing the molten metal, and an inert gas is blown out to the molten metal from a plurality of gas injection nozzles arranged around the molten metal nozzle. The flow of molten metal from the molten metal nozzle is divided by the inert gas flow from the gas injection nozzle into a plurality of fine metal droplets, and the droplets fall into the spray tank, are spheroidized by surface tension, and are solidified. Thereby, the spherical metal powder is collected by the collecting hopper at the bottom of the spray tank.

As disclosed in japanese patent application laid-open No. 2016 and 211027, there is an apparatus for producing metal powder comprising a tank which is provided above a spray chamber (spray tank) and holds a metal solution, an atomizing nozzle which is connected to the bottom of the tank and blows out the inert gas to drop the metal solution into the spray chamber, a gas inlet and a gas outlet for gas replacement in the spray chamber, and a second gas inlet for supplying a gas for making the interior of the spray chamber an oxidizing atmosphere and/or a nitriding atmosphere.

Disclosure of Invention

Problems to be solved by the invention

In recent years, there has been an increasing demand for materials having a smaller particle size than that of metal powder required by the conventional atomization method, such as materials for metal 3D printers in which a large number of metal particles are stacked to form a metal having a desired shape. The particle size of the metal powder used in powder metallurgy, welding, and the like is, for example, about 70 to 100 μm, and the particle size of the metal powder used in 3D printers is, for example, about 20 to 50 μm, and is very fine.

As described above, as one of the methods for mass-producing fine metal particles in a shorter time, there is a method for enlarging the diameter of a molten metal nozzle, and there is a fear that the recovery rate of metal powder having a desired particle diameter is reduced. In order to improve the recovery rate, it is considered to increase the gas pressure discharged from the spray nozzle and to miniaturize and uniformize the particle size of the metal particles, but the metal particles accelerated by the increase of the gas pressure are likely to collide with the wall surface of the spray tank before solidification and to be deformed, and it is not possible to estimate the increase of the recovery rate. In order to avoid collision between the metal particles and the spray groove, the diameter of the spray groove may be increased, and thus, there may be a problem that cost increase and installation space accompanying replacement of the spray groove cannot be secured.

The invention aims to provide a metal powder manufacturing device, a gas injector and a tank device thereof, which can manufacture fine metal powder efficiently without changing the size of a spray tank.

Means for solving the problems

The present application includes a plurality of solutions to the above-described problems, and includes, for example, a spray tank, and a plurality of spray nozzles for spraying a molten metal into the spray tank, each of the plurality of spray nozzles including a molten metal nozzle for flowing the molten metal into the spray tank, and a plurality of gas injection nozzles disposed around the molten metal nozzle and including gas injection holes for causing a gas fluid to collide with the molten metal flowing from the molten metal nozzle.

Effects of the invention

According to the present invention, fine metal powder can be efficiently produced without changing the size of the spray tank.

Drawings

Fig. 1 is an overall configuration diagram of a gas atomizing apparatus as a metal powder production apparatus.

Fig. 2 is a sectional view of the periphery of the metal sprayer 200 of the gas atomizing apparatus of the first embodiment.

Fig. 3 is a perspective view of the metal sprayer 200 of the first embodiment.

Fig. 4 is a diagram showing the relationship between the gas injection direction of the plurality of injection holes 9 constituting the first gas injection nozzle 2A and the molten metal downflow region 27 of the first molten metal nozzle 11A.

Fig. 5 is a perspective view of a metal sprayer 200 according to a second embodiment.

Fig. 6 is a perspective view of a metal sprayer 200 according to a third embodiment.

Fig. 7 is a perspective view of a metal sprayer 200 according to a fourth embodiment.

Fig. 8 is a schematic cross-sectional view of the metal sprayer 200, which is formed by a vertical plane including the central axis Cg0 of the metal sprayer 200 and two points Tc1 and Tc2 described later.

Fig. 9 is a diagram showing the relationship between the gas injection direction of the plurality of injection holes 9 constituting the first gas injection nozzle 2A of fig. 7 and the molten metal downflow region 27 of the first molten metal nozzle 11A.

Fig. 10 is a particle size distribution diagram of metal powder produced by a gas atomizing apparatus having the same spraying conditions of the respective spray nozzles.

Fig. 11 is a sectional view of the vicinity of an example of a metal atomizer of a gas atomizer according to a fifth embodiment.

Fig. 12 is a sectional view of the vicinity of an example of a metal atomizer of a gas atomizer according to a fifth embodiment.

Fig. 13 is a sectional view of the vicinity of an example of a metal atomizer of a gas atomizer according to a fifth embodiment.

Fig. 14 is a sectional view of the vicinity of an example of a metal atomizer of a gas atomizer according to a fifth embodiment.

Fig. 15A is a sectional view of the vicinity of an example of a metal atomizer of a gas atomizer according to a fifth embodiment.

Fig. 15B is an enlarged view of a molten metal nozzle in an example of a metal spraying apparatus of a gas atomizing apparatus according to a fifth embodiment.

Fig. 16 is a table summarizing the tendency of the particle size of the metal powder obtained in 6 examples in which any of 6 spraying conditions (1) to (6) was changed from the particle size of the metal powder obtained from the standard spray nozzle.

Fig. 17 is a particle size distribution diagram of metal powder produced by an example of a gas atomizing apparatus in which the atomizing conditions of the respective atomizing nozzles are different.

Fig. 18 is a particle size distribution diagram of metal powder produced by an example of a gas atomizing apparatus in which the atomizing conditions of the respective atomizing nozzles are different.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is an overall configuration diagram of a gas atomizing apparatus as a metal powder production apparatus of the present invention. The gas atomizing apparatus shown in fig. 1 includes a dissolving tank (also referred to as a tundish part) 1 as a container for storing molten metal (molten metal) as liquid metal, a metal atomizing apparatus 200 for spraying liquid on the molten metal by blowing high-pressure gas (gas fluid) to the molten metal flowing down from the dissolving tank 1 through a molten metal nozzle (described later) 11 as fine particles to pulverize the fine particles into a plurality of fine particles, a jet gas supply pipe (jet fluid supply pipe) 3 for supplying the high-pressure gas to the metal atomizing apparatus 200, a spray tank 4 as a container held in an inert gas environment for rapidly condensing the fine particle liquid metal sprayed from the metal atomizing apparatus 200 while dropping, and a collection hopper 5 provided at the bottom of the spray tank 4 for collecting the solid metal in powder form solidified while dropping in the spray tank 4.

The inside of the dissolution tank 1 is preferably kept in an inert gas atmosphere. The spray tank 4 is a cylindrical container having the same diameter in the upper portion and the middle portion, and is a conical shape having a diameter that decreases toward the collecting hopper 5 in the lower portion from the viewpoint of easiness of recovery of the metal powder by the collecting hopper 5. The inert gas is discharged from the collection hopper 5 as a suitable exhaust gas 6.

< first embodiment >

Fig. 2 is a sectional view of the vicinity of the metal sprayer 200 of the gas atomizing apparatus according to the first embodiment, and fig. 3 is a perspective view of the metal sprayer 200 according to the first embodiment. In fig. 3, the first and second molten steel nozzles 11A and 11B, which will be described later, are not shown.

Spray nozzles 20A, 20B

The metal spraying apparatus 200 includes a plurality of molten metal nozzles 11A and 11B for flowing molten metal into the spray tank 4, and a gas injector 70 for injecting gas from a plurality of gas injection nozzles 2A and 2B provided below the dissolution tank (tank portion) 1. The metal spraying apparatus 200 is configured such that a plurality of spray nozzles 20A and 20B for spraying a liquid of a molten metal into the spray tub 4 are formed on the bottom surface of the gas injector 70 facing the inside of the spray tub 4. The gas atomizing device of the present embodiment includes two spray nozzles of the first spray nozzle 20A and the second spray nozzle 20B. The first and second spray nozzles 20A and 20B respectively include molten metal nozzles 11A and 11B for flowing molten metal into the spray bath 4, and a plurality of gas injection nozzles 2A and 2B arranged around the molten metal nozzles 11A and 11B. That is, each spray nozzle 20 has a pair of molten metal nozzles 11 and a pair of gas injection nozzles 2.

Molten metal nozzles 11A, 11B-

As shown in fig. 2, a first molten metal nozzle 11A and a second molten metal nozzle 11B for allowing the molten metal in the dissolution tank 1 to flow into the spray tank 4 are provided on the bottom of the dissolution tank (tank part) 1 so as to protrude vertically downward from the bottom surface of the dissolution tank 1. The first molten metal nozzle 11A and the second molten metal nozzle 11B have the same shape, and have a long hole extending in the vertical direction in the molten metal flow inside each nozzle. The vertically long hole is a molten metal flow path through which molten metal flows vertically downward from the bottom of the melting tank (tank portion) 1.

As shown in fig. 3, the gas injector 70 having a substantially cylindrical outer shape is provided with a first molten metal nozzle insertion hole 12A and a second molten metal nozzle insertion hole 12B as two cylindrical through holes having axes (Cm1, Cm2) parallel to the axis (Cg0) of the cylinder. The first molten metal nozzle 11A and the second molten metal nozzle 11B are inserted into the first molten metal nozzle insertion hole 12A and the second molten metal nozzle insertion hole 12B, respectively. The dissolution tank 1 is supported by the gas injector 70. In addition, it is preferable to insert a heat insulating material between the dissolution tank 1 and the gas injector 70 in view of preventing heat conduction from the dissolution tank 1, which is not shown in the drawings.

As shown in fig. 3, the centers of the first molten metal nozzle insertion hole 12A and the second molten metal nozzle insertion hole 12B can be arranged on the same straight line as the center of the cylindrical gas injector 70, and the distances from the central axis Cg0 of the gas injector 70 to the central axes Cm1, Cm2 of the first molten metal nozzle insertion hole 12A and the second molten metal nozzle insertion hole 12B can be arranged in the same manner. Further, the central axes Cm1, Cm2 of the first molten metal nozzle insertion hole 12A and the second molten metal nozzle insertion hole 12B can be aligned with the central axes of the holes of the first molten metal nozzle 11A and the second molten metal nozzle 11B.

The open ends 21A, 21B located at the lower ends of the first molten metal nozzle 11A and the second molten metal nozzle 11B are arranged to protrude from the bottom surface of the gas injector 70 and face the cavity in the spray groove 4. The molten metal in the dissolution tank 1 flows down through the holes in the first and second molten metal nozzles 11A and 11B as a molten metal flow 8 and flows out (flows down) into the spray tank 4 through the opening ends 21A and 21B. The minimum inner diameter of the first molten steel nozzle 11A and the second molten steel nozzle 11B, which is a size contributing to the diameter of the molten steel introduced into the spray groove 4 (the size of the diameter of the downflow zone 27 described later), can be selected to be 1 to 2mm smaller than the conventional one.

Gas injection nozzles 2A, 2B-

The gas injector 70 has a hollow cylindrical outer shape filled with a high-pressure inert gas, and the inside thereof is a gas flow path 50 for forming a gas flow around each of the plurality of molten metal nozzle insertion holes 12A and 12B. The gas flow path 50 receives a supply of high-pressure gas from the injection gas supply pipe 3 connected to a gas suction hole (not shown) provided in a side surface of the cylinder of the gas injector 70. The gas injector 70 injects the high-pressure gas supplied to the gas flow path 50 as a directional gas torch (gas jet) 10 through a plurality of injection holes 9 provided in the bottom surface of the gas injector 70. The plurality of injection holes 9 are arranged so as to draw circles around the opening end on the spray groove side of the first molten metal nozzle insertion hole 12A and around the opening end on the spray groove side of the second molten metal nozzle insertion hole 12B, respectively, the plurality of injection holes 9 surrounding the opening end on the spray groove side of the first molten metal nozzle insertion hole 12A constitute the first gas injection nozzle (first gas injection part) 2A, respectively, and the plurality of injection holes 9 including the opening end on the spray groove side of the second molten metal nozzle insertion hole 12B constitute the second gas injection nozzle (second gas injection part) 2B, respectively. The gas injection nozzles 2A and 2B are provided in each of the plurality of molten metal nozzle insertion holes 12A and 12B, and inject the gas in the gas flow path 50 from the open ends of the molten metal nozzle insertion holes 12A and 12B to the outside of the gas injector 70.

Fig. 4 is a diagram showing the relationship between the gas injection direction of the plurality of injection holes 9 constituting each first gas injection nozzle (first gas injection portion) 2A and the molten metal downflow region 27 of the first molten metal nozzle 11A.

In fig. 4, the gas injection direction of the plurality of injection holes 9 constituting the plurality of first gas injection nozzles (first gas injection portions) 2A is indicated by a straight line 25, and each injection hole 9 is formed by piercing a through hole having a central axis coincident with the corresponding straight line 25 in the bottom surface of the gas injector 70. The plurality of spouting holes 9 are arranged on the bottom surface of the gas spouting hole 70 at regular intervals on a circle concentric with the central axis Cm1 of the first molten metal nozzle insertion hole 12A. This circle formed by the plurality of injection holes 9 is referred to as a circle 90 in fig. 4. The gas injection direction (straight line 25) of all the injection holes 9 constituting the plurality of first gas injection nozzles 2A passes through a common focal point (first focal point) 26. That is, the gas ejection directions of all the ejection holes 9 are concentrated at one point (focal point 26). The focal point 26 is located in a substantially columnar flowing-down region 27 defined by the outer shape of the molten metal flowing down from the first molten metal nozzle 11A (not shown in fig. 4). The diameter of the downflow region 27 is smaller than the diameter of the first molten steel nozzle insertion hole 12A, and can be appropriately adjusted according to the minimum inner diameter of the hole constituting the first molten steel nozzle 11A. The diameter of the downflow region 27 may be, for example, a value equal to or smaller than the diameter of the open end 21A of the first molten steel spout 11A.

Note that, although not described, the plurality of ejection holes 9 constituting the plurality of second gas injection nozzles 2B are also formed in the same manner as the plurality of ejection holes 9 constituting the plurality of first gas injection nozzles 2A. The focal point 26 of the plurality of ejection holes 9 constituting the plurality of second gas ejection nozzles 2B is sometimes referred to as a second focal point.

Action effect

In the metal powder manufacturing apparatus configured as described above, when the high-pressure gas is supplied from the injection gas supply pipe 3, the high-pressure gas of the same pressure is injected into the spray groove 4 from all the injection holes 9 constituting the plurality of first gas injection nozzles 2A and second gas injection nozzles 2B in the metal spraying apparatus 200 in the injection direction (straight line 25) predetermined for each injection hole 9. At this time, the first gas injection nozzle 2A and the second gas injection nozzle 2B collectively inject gas toward the respective focuses (first focus and second focus) 26, and form a fluid film in an inverted conical shape (first inverted conical shape and second inverted conical shape) having the focus 26 shown in fig. 4 as a vertex and the circle 90 on which the plurality of injection holes 9 are arranged as a bottom surface.

On the other hand, when molten metal is poured into the melting tank 1, the two molten metal flows 8 flow down into the downflow zone 27 through the first molten metal nozzle 11A and the second molten metal nozzle 11B provided on the bottom surface of the melting tank 1 with respect to the inside of the spray tank 4. The molten metal flow 8 collides with the fluid film of the high-pressure gas in the shape of an inverted cone (first inverted cone shape or second inverted cone shape) in the vicinity of the two focal points 26 of the first gas injection nozzle 2A and the second gas injection nozzle 2B, and is pulverized into a plurality of fine particles 15. The metal of the fine particles (fine particles 15) which are made into a liquid by the injection gas from the first and second gas injection nozzles 2A and 2B is rapidly cooled and solidified during the fall in the spray tank 4, and is collected as a plurality of metal powders by the collection hopper 5.

In the present embodiment, a value (e.g., 1 to 2mm) smaller than the previous value (e.g., about 5 mm) is selected as the minimum inner diameter of the holes constituting the first molten metal nozzle 11A and the second molten metal nozzle 11B, and thus, even if the gas is ejected from the gas ejection nozzles 2A and 2B at the same pressure as before, metal ions having a diameter smaller than the previous value can be easily obtained. In addition, even when the gas is injected at the same pressure as before, the flight distance of the metal particles in the spray groove 4 can be suppressed, and therefore, it is not necessary to replace the spray groove 4 having a large diameter and enlarge the installation space of the spray groove 4 in order to prevent the metal particles from being deformed. On the other hand, since the minimum inner diameter is smaller than before, if it is observed that the flow rate of the molten steel stream 8 per unit time is lower than before and the recovery rate is lower in each of the molten steel nozzles 11A and 11B, the recovery rate per unit time can be doubled because the present embodiment includes two molten steel nozzles 11A and 11B (i.e., two spray nozzles 20A and 20B) for one spray tank 4.

In the present embodiment, two focal points 26 are set at the center of the molten metal flowing-down region 27, and the injection holes 9 are uniformly arranged on a circle concentric with the central axes Cm1, Cm2 of the first and second molten metal nozzle insertion holes 12A, 12B, so that the high-pressure gas from the injection holes 9 is uniformly injected to the molten metal flow 8 in 360 degrees. This can make the particle size of fine particles 15 uniform.

That is, according to the present embodiment, fine metal powder can be efficiently produced without changing the size of the spray tank 4.

The two spray nozzles 20A and 20B of the present embodiment each include a pair of molten metal nozzles 11 and a pair of gas injection nozzles 2. In this way, when the spray nozzle 20 is constituted by a single set of the molten metal nozzle 11 and the spray nozzle 2, the particle diameter of the liquid metal sprayed from each spray nozzle 20 can be controlled more finely, for example, compared to a spray nozzle in which a plurality of spray holes 9 are arranged so as to surround all the molten metal nozzles 11 by providing a plurality of molten metal nozzles 11. For example, as in the fifth embodiment described later, the particle size distribution of the metal powder can be set to a desired distribution between fine particles and coarse particles by changing the spraying conditions of the nozzles.

The gas injector 70 of the present embodiment includes a plurality of molten metal nozzle insertion holes 12A and 12B, and a gas flow path 50 for forming a gas flow around each of the plurality of molten metal nozzle insertion holes 12A and 12B. The gas flow in the gas flow path 50 has a function of cooling the molten metal nozzles 11A and 11B in the molten metal flow-down by heat exchange before being ejected from the ejection holes 9. In the gas injector 70 of the present embodiment, the gas flow passage 50 is formed around each of the plurality of molten metal nozzles 11A and 11B, and the molten metal nozzles 11A and 11B are cooled from the periphery thereof by heat exchange with the gas flow in the flow passage 50. This can prevent local temperature increases, i.e., uneven temperature distributions from occurring in the molten metal nozzles 11A and 11B, and can reduce the possibility of damage to the molten metal nozzles 11A and 11B due to uneven temperature distributions. In particular, in the gas injector 70 of the present embodiment, since the molten metal nozzle insertion holes 12A and 12B, the injection hole 9, and the gas flow path 50 are symmetrically provided with respect to the central axis Cg0, there is an advantage in that the temperature distribution of the gas injector 70 and the molten metal nozzles 11A and 11B in the plane perpendicular to the central axis Cg0 can be made uniform.

The tank part (melting tank) 1 for storing the molten metal described in the above embodiment and the molten metal nozzles 11A and 11B provided downward from the bottom of the tank part 1 and forming a molten metal flow path through which the molten metal flows downward from the bottom of the tank part 1 may be collectively referred to as a "tank".

< second embodiment >

In the first embodiment described above, since the two spray nozzles 20A and 20B are provided in the spray tank 4 having the same diameter as before, there is a possibility that the fine particles 15 sprayed from the spray nozzles 20A and 20B collide and deform before they are solidified in the spray tank 4. This embodiment is one of embodiments for attempting to solve the problem.

Fig. 5 is a perspective view of a metal sprayer 200 according to a second embodiment. In addition, the first and second molten metal nozzles 11A and 11B are not shown in the same manner as in fig. 3. The other portions are the same as those of the first embodiment, and the description thereof is omitted.

The seal gas jet nozzle 30A is provided on the bottom surface of the gas injector 70 in fig. 5 via a plurality of injection holes 31 that are linearly arranged in front of the adjacent 2 spray nozzles 20A, 20B (in other words, the 2 molten metal nozzle insertion holes 12A, 12B) with a predetermined interval therebetween. The straight line in which the plurality of injection holes 31 are arranged intersects the central axis Cg0 of the gas injector 70 and passes through the center of the bottom surface of the gas injector 70. Each of the injection holes 31 is formed by a through hole penetrating a central axis extending in a substantially vertical direction in a bottom surface of the gas injector 70. Similarly to the injection holes 9, the high-pressure gas can be supplied from the injection gas supply pipe 3 to each injection hole 31, and the high-pressure gas can be injected in the vertical downward direction which is the axial direction of each injection hole 31. Thereby, a film-like jet (air curtain, seal gas jet) 35 is formed which divides at least an upper region (space) of the spray tank 4 into two.

The thus formed film-like jet stream 35 functions as an air curtain, and can prevent fine particles 15 sprayed from the first spray nozzle 20A (molten metal flowing down from the molten metal 11A) from colliding with fine particles 15 sprayed from the second spray nozzle 20B (molten metal flowing down from the molten metal nozzle 11B). As a result, generation of deformed metal particles is prevented, and the production efficiency of the metal powder can be improved as compared with the first embodiment. Further, even when, for example, the spray groove 4 having the same diameter as before is used, collision of the fine particles 15 can be prevented, and therefore, the replacement cost and installation space of the spray groove 4 can be prevented from increasing.

Further, the plurality of injection holes 31 are preferably arranged so as to cross the bottom surface of the gas injector 70 as shown in fig. 5 from the viewpoint of preventing collision of particles with each other, but may be arranged so as to be concentrated only on a portion (for example, the vicinity of the central axis Cg0) where collision of particles with each other is predicted to occur frequently, and the arrangement of the other portions may be omitted. In the above example, the plurality of injection holes 31 are arranged linearly, but may be arranged in a curved line. The gas injector 70 may be divided to supply a gas of a different pressure and type from those of the jet holes 9 to the jet holes 31.

< third embodiment >

The present embodiment is a modification of the second embodiment, and as described below, even if the metal sprayer 200 (gas injector 70) is configured, collision of fine particles 15 with each other can be prevented by the film-like jet stream 35.

Fig. 6 is a perspective view of a metal sprayer 200 according to a third embodiment. The first and second molten metal nozzles 11A and 11B are not shown in the same manner as in fig. 3 and the like. The other portions have the same configurations as those of the first embodiment, and the description thereof is omitted.

As the seal gas jet nozzle 30B, a slit 32, which is an elongated gap linearly extending between the two adjacent spray nozzles 20A and 20B, is provided on the bottom surface of the gas injector 70 in fig. 6. The slit 32 intersects the central axis Cg0 of the gas injector 70 and passes through the center of the bottom surface of the gas injector 70. The slit 32 is formed by penetrating a through hole in the bottom surface of the gas injector 70. The slit 32 is configured to be capable of supplying high-pressure gas from the injection gas supply pipe 3, similarly to the injection hole 9, and the high-pressure gas is injected vertically downward from the slit 32. Thereby, a film-like jet (air curtain) 35 is formed that divides at least an upper region of the spray tank 4 into two.

Since the film-like jet stream 35 thus formed prevents the fine particles 15 sprayed from the first spray nozzle 20A from colliding with the fine particles 15 sprayed from the second spray nozzle 20B, the generation of deformed metal particles can be prevented, and the efficiency of producing metal powder can be improved compared to the first embodiment.

From the viewpoint of preventing the particles from colliding with each other, as shown in fig. 6, the slits 32 are preferably arranged to cross the bottom surface of the gas injector 70, but may be arranged so as to be concentrated only on a portion where collision of the particles is predicted to occur frequently (for example, near the central axis Cg0), and the arrangement of the other portions may be omitted. Further, the inside of the gas injector 70 may be divided, and the gas of a pressure and a type different from those of the ejection holes 9 may be supplied to the slit 32.

< fourth embodiment >

The present embodiment is one of embodiments in which attempts are made to solve the same problem (collision or deformation of the fine particles 15 before solidification sprayed from the two adjacent spray nozzles 20A and 20B) as the second and third embodiments, and corresponds to a mode in which the plurality of gas injection nozzles 2A and 2B of the first embodiment are inclined at the predetermined angle θ.

Fig. 7 is a perspective view of a metal sprayer 200 according to a fourth embodiment, and fig. 8 is a schematic cross-sectional view of the gas injector 70, which is formed by a vertical plane including a central axis Cg0 of the gas injector 70 and two points Tc1 and Tc2 described later. In fig. 7, the first and second molten steel nozzles 11A and 11B are not shown, and fig. 8 shows only the outer shape of the gas injector 70 in cross section. Descriptions of the same parts as those of the previous embodiments are omitted as appropriate.

First, a first circular surface 45A having the same center as the circle 90 on which all the ejection holes 9 constituting the plurality of first gas injection nozzles (first gas injection portions) 2A of the first embodiment are arranged and having a diameter including all the ejection holes 9 constituting the plurality of first gas injection nozzles 2A is set (see fig. 3). At this time, as shown in fig. 8, the first circular surface 46A of the plurality of first gas injection nozzles 2A of the fourth embodiment shown in fig. 7 corresponds to the surface of the first circular surface 45A being inclined upward at a predetermined angle θ about a point (inclination center) Tc1 provided at a point closest to the central axis Cg0 on the circumference of the first circular surface 45A. Similarly, if the second circular surface 45B (not shown) is set in the plurality of second gas injection nozzles (second gas injection portions) 2B, the second circular surface 46B of the plurality of second gas injection nozzles 2B in fig. 7 is inclined upward at the predetermined angle θ about a point (inclination center) Tc2 set at a point closest to the central axis Cg0 on the circumference of the second circular surface 45B.

In fig. 7, the plurality of injection holes 9 constituting the plurality of first gas injection nozzles (first gas injection portions) 2A and the plurality of second gas injection nozzles (second gas injection portions) 2B are arranged at equal intervals on the circumference of a circle 90 of the same diameter centering on two points Pg1 and Pg2 that are points on the first circular surface 46A and the second circular surface 46B and are equidistant from the central axis Cg0, respectively. The two points Pg1 and Pg2 are center points of the first and second inverted conical bottom surfaces of the fluid films forming the injected gas from the plurality of first and second gas injection nozzles 2A and 2B.

Unlike the first embodiment, the center point Pg1 of the bottom surface of the inverted cone is located inside the circle 90 formed by the plurality of injection holes 9, apart from the center axis Cm1 of the first molten steel nozzle insertion hole 12A. Similarly, the center point Pg2 is also located inside the circle 90 formed by the plurality of injection holes 9 apart from the center axis Cm2 of the second molten steel nozzle insertion hole 12B. More specifically, in a range where the open end of the first molten metal nozzle insertion hole 12A does not overlap with the open end of the injection hole 9 (i.e., in a range where the first molten metal 11A does not overlap with the plurality of gas injection nozzles 2A corresponding thereto), the center axis Cm1 is located radially outward of the bottom surface of the gas injector 70 (i.e., on the inner side surface side of the spray groove 4) with respect to the center point Pg1, and similarly, in a range where the open end of the second molten metal nozzle insertion hole 12B does not overlap with the open end of the injection hole 9 (i.e., in a range where the second molten metal nozzle 11B does not overlap with the plurality of gas injection nozzles 2B corresponding thereto), the center axis Cm2 is located radially outward of the bottom surface of the gas injector 70 (i.e., on the inner side surface side of the spray groove 4) with respect to the center point Pg 2.

A straight line 41A connecting the center point Pg1 of the first inverted conical bottom surface (i.e., the circle 90) of the fluid film formed by the ejection gas of the plurality of first gas ejection nozzles 2A and the apex (the first focal point 26) thereof, and a straight line 41B connecting the center point Pg2 of the second inverted conical bottom surface (i.e., the circle 90 (not shown)) of the fluid film formed by the plurality of second gas ejection nozzles 2B and the apex (the second focal point 26) thereof are defined in the same manner. In the two straight lines 41A and 41B, the directions from the center points Pg1 and Pg2 to the first and second focal points 26 are defined as focal directions, and the directions are indicated by arrows in fig. 7.

In the present embodiment, as shown in fig. 7, the gas ejection directions of the plurality of holes 9 in the plurality of first gas ejection nozzles 2A and the plurality of second gas ejection nozzles 2B (i.e., the axial directions of the ejection holes (through holes) 9) are adjusted as shown in fig. 9 such that the straight lines 41A and the straight lines 41B draw inverted V-shapes. However, it is preferable to adjust the gas ejection directions 25 of the plurality of holes 9 constituting the plurality of first gas ejection nozzles 2A and the plurality of second gas ejection nozzles 2B so that the straight lines 41A and the straight lines 41B are arranged on the same plane passing through the central axis Cg 0.

Fig. 9 is a diagram showing the relationship between the gas injection direction of the plurality of injection holes 9 constituting the plurality of first gas injection nozzles 2A of fig. 7 and the molten metal flowing-down region 27 of the first molten metal nozzle 11A. In fig. 9, illustration of the first molten metal nozzle 11A is omitted.

The plurality of injection holes 9 constituting the plurality of first gas injection nozzles (first gas injection portions) 2A of the figure are formed by respectively passing through holes having central axes coinciding with the straight lines 25 shown in the figure in the bottom surface of the gas injector 70. That is, in the present embodiment, the central axes of all the ejection holes 9 of the plurality of first gas ejection nozzles 2A are also inclined at θ from the state of fig. 4 (the state of the first embodiment), and the direction of the focal point 26 is inclined at θ toward the inner surface of the spray groove 4.

In fig. 9, the first focal point 26 is located in a substantially columnar flowing-down region 27 defined by the outer shape of the molten metal flowing down from the first molten metal nozzle 11A (not shown in fig. 9). The first focal point 26 is located radially outward of the bottom surface of the gas injector 70 from the center point Pg1 of the bottom surface of the inverted cone. Note that, although not described, the center point Pg1 of the bottom surface of the inverted cone of the plurality of second gas injection nozzles 2B and the second focal point 26 as the vertex thereof are also arranged in the same positional relationship as the center point Pg1 and the first focal point 26 of the first gas injection nozzle 2A.

Action effect

In the metal powder production apparatus configured as described above, when the high-pressure gas is supplied from the injection gas supply pipe 3, the high-pressure gas of the same pressure is injected from all the injection holes 9 constituting the plurality of first gas injection nozzles 2A and second gas injection nozzles 2B in a predetermined injection direction (straight line 25). At this time, the first gas injection nozzle 2A and the second gas injection nozzle 2B collectively inject gas to the respective focal points (first focal point and second focal point) 26, and form a fluid film in an inverted cone shape (first inverted cone shape and second inverted cone shape) having a circle where the plurality of injection holes 9 are arranged as a bottom surface with the focal point 26 as a vertex as shown in fig. 9. The inverted cone in this case is inclined at a predetermined angle θ, and becomes a right circular cone in which straight lines 41A and 41B connecting the centers Pg1 and Pg2 of the conical bottom surface and the vertex are perpendicular to the conical bottom surface, as in the first embodiment.

On the other hand, the molten metal flow 8 flowing down through the first molten metal nozzle 11A and the second molten metal nozzle 11B collides with an inclined inverted conical (forward conical) fluid film in which high-pressure gas is formed near the two focal points 26 of the plurality of first gas injection nozzles 2A and the plurality of second gas injection nozzles 2B, and is pulverized into the plurality of fine particles 15. At that time, the fine particles 15 are applied to the radial outer side of the atomizing groove 4 (the inner side surface side of the atomizing groove 4) at a speed by the plurality of first gas injection nozzles 2A and the plurality of second gas injection nozzles 2B which are inclined, and are scattered to the inner side surface of the atomizing groove 4 as shown in fig. 7. That is, since the fine particles 15 ejected from the first spray nozzle 20A and the fine particles 15 ejected from the second spray nozzle 20B are scattered in different directions, they can be prevented from colliding and deforming during falling in the spray tank 4. Therefore, according to the present embodiment, the manufacturing efficiency of the metal powder can be improved as compared with the first embodiment.

Further, although the recovery rate of the metal powder having a desired particle diameter may be lower than that described in the fourth embodiment, even if the gas injection direction (central axis direction) of the plurality of injection holes 9 is appropriately changed in the configuration of the first embodiment, the plurality of gas injection nozzles 2A and 2B can apply a velocity toward the inner surface side of the spray groove 4 to the fine particles 15 by replacing the fluid film formed by the gas from a normal cone to an oblique cone, and thus the fine particles 15 can be prevented from colliding with each other.

Further, from the viewpoint of avoiding collision of fine particles 15 with each other, it is preferable that the scattering direction in the horizontal direction of fine particles 15 ejected from first spray nozzles 20A and fine particles 15 ejected from second spray nozzles 20B is made to be opposite, and therefore, it is preferable that a plurality of first gas injection nozzles 2A and a plurality of second gas injection nozzles 2B are provided so that the central axis Cg0 is flush with the two center points Pg1 and Pg 2.

In the above description, the inclination angles of the gas injection nozzles 20A and 20B of the two spray nozzles 20A and 20B are made to be the same for the sake of simplicity of explanation, but the inclination angles may be different.

< fifth embodiment >

In the present embodiment, the spraying conditions of the plurality of spraying nozzles 20A and 20B are different from each other, so that the particle size distribution (also referred to as "particle size distribution") of the metal powder produced in the single-group gas spraying apparatus (metal powder production apparatus) can be controlled.

As described above in the first to fourth embodiments, when the spraying conditions are made the same in the plurality of spraying nozzles 20A, 20B, the particle size distribution of the produced metal powder is normally a normal distribution in which the average particle size (average diameter) defined by the spraying conditions is a peak, as shown in fig. 10. That is, if the spraying conditions are the same, the particle diameter of the metal powder to be produced tends to be concentrated on one peak. However, the particle size desired by many users is not always equal to the peak value, and there are users who desire a powder having a particle size deviating from the peak value (for example, a powder deviating from a range of μ (average) ± σ (standard deviation) (1 σ range)), or a powder having a particle size in a relatively wide range (for example, a range larger than 1 σ range). Therefore, if such a requirement is required, the metal powder recovery rate may be reduced in a gas spray apparatus in which the particle size distribution of the metal powder has a normal distribution having one peak (that is, a gas spray apparatus in which the spray conditions of the spray nozzles are the same).

Therefore, in the present embodiment, the plurality of spray nozzles 20A and 20B are different in spray conditions. Specifically, the changeable spray conditions include, for example, (1) the spray pressure of the gas fluid sprayed from the plurality of gas spray nozzles 2, (2) the angle of the spray holes 9 in the plurality of gas spray nozzles 2, (3) the diameter of the spray holes 9 in the plurality of gas spray nozzles 2, (4) the number of the spray holes 9 in the plurality of gas spray nozzles 2, (5) the minimum diameter (flow diameter) of the molten metal nozzle 11, and (6) the tip shape of the molten metal nozzle 11. Next, a configuration for realizing these spraying conditions will be described with reference to fig. 11 to 15.

Spraying conditions (1): the ejection pressure of the gas fluid ejected from the plurality of gas ejection nozzles 2

Fig. 11 is a sectional view of the periphery of the metal spraying device 210 in which the injection pressures of the gas fluid (high-pressure gas) injected from the gas injection nozzle 2A of the spraying nozzle 20A and the gas fluid injected from the gas injection nozzle 2B of the spraying nozzle 20B can be made different from each other. Unlike the first embodiment in which the gas flow passage 50 common to the two gas injection nozzles 2A and 2B is used, the metal sprayer 210 in the figure includes independent internal flow passages 50A and 50B connected to gas supply sources (not shown) having different pressures. The gas fluids are supplied to the internal flow paths 50A and 50B from gas supply sources having different pressures through different injection gas supply pipes 3A and 3B, and the gas fluids having different injection pressures are injected from the gas injection nozzles 2A and 2B.

For example, when a relatively high-pressure gas is introduced into the internal flow path 50B and a gas fluid having a higher pressure than that of the gas injection nozzle 2A is injected from the gas injection nozzle 2B, the molten metal flowing down from the second molten metal injection nozzle 11B is pulverized so as to be finer than the molten metal flowing down from the first molten metal injection nozzle 11A by the high-pressure gas injected from the gas injection nozzle 2B, and therefore the particle size of the metal sprayed from the spray nozzle 20B is made finer than the particle size sprayed from the spray nozzle 20A. That is, the metal powder tends to be more finely pulverized as the ejection pressure of the gas fluid ejected from the gas ejection nozzle 2 is increased. As a result, the particle size distributions of the metal ejected from the two spray nozzles 20A and 20B having different gas ejection pressures are different, and as shown in fig. 17, two peaks (average particle diameters μ 1 and μ 2) appear in the particle size distribution of the metal powder. In fig. 17, when the average particle diameter of the metal powder ejected from the spray nozzle 20A is μ 1, the average particle diameter of the metal powder ejected from the spray nozzle 20B is μ 2 smaller than μ 1. Thus, the particle size distribution of the metal powder in this case is a distribution obtained by combining two normal distributions of different average particle sizes μ 1 and μ 2 defined by the spraying conditions of the two spray nozzles 20A and 20B. Therefore, metal powder having a wide range of particle sizes can be produced at one time as compared with the case where the spraying conditions of the spray nozzles 20A and 20B are the same (see fig. 10).

Fig. 16 is a table summarizing the tendency of the particle size of the metal powder obtained in the six examples in which any of the above-described spraying conditions (1) to (6) was changed with respect to the standard spray nozzle (marked as "comparative example" in the figure, for example, any of the spray nozzles 20A and 20B of the first embodiment).

Example 1 in fig. 16 corresponds to the spray nozzle 20B in fig. 11 in which the above-described spray condition (1) is changed from the comparative example (here, the spray nozzle 20A in the first embodiment), and the jet pressure of the gas jet nozzle 2 is set to a value 1.5 times that of the comparative example by the independence of the gas flow paths (the internal flow paths 50A and 50B). In this case, the particle size of the metal powder produced by the spray nozzle of example 1 was fine compared to the comparative example.

Spraying conditions (2): angle of injection hole 9 in multiple gas injection nozzles 2

Fig. 12 is a cross-sectional view of the periphery of the metal sprayer 220 in which the angles (inclination angles) of the ejection hole 9a of the gas ejection nozzle 2A of the spray nozzle 20A and the ejection hole 9 of the gas ejection nozzle 2B of the spray nozzle 20B are different from each other. The angle of the injection hole 9 (injection hole 9a) is defined as shown in the drawing by an angle θ 9(θ 9a) that can be assumed between the center hole 25 of the injection hole 9 (injection hole 9a) and the center axis Cm2 of the second molten metal nozzle insertion hole 12B (center axis Cm1 of the first molten metal nozzle insertion hole 12A) (however, θ 9 and θ 9a are less than 90 degrees). In the metal sprayer 220 of the figure, unlike the first embodiment in which the angle of the common ejection hole 9 is used in both the gas ejection nozzles 2A and 2B, the angle θ 9a of the plurality of ejection holes 9a belonging to the gas ejection nozzle 2A and the angle θ 9 of the plurality of ejection holes 9 belonging to the gas ejection nozzle 2B are different from each other. Specifically, the angle θ 9a of the plurality of ejection holes 9a belonging to the gas injection nozzle 2A is set smaller than the angle θ 9 of the plurality of ejection holes 9 belonging to the gas injection nozzle 2B.

As shown in fig. 12, when the angle θ 9a of the plurality of injection holes 9a belonging to the gas injection nozzle 2A (the spray nozzle 20A) is reduced as compared with the angle θ 9 of the plurality of injection holes 9 belonging to the gas injection nozzle 2B (the spray nozzle 2B), the grain size of the metal ejected from the spray nozzle 20A is coarsened as compared with the grain size ejected from the spray nozzle 20B. That is, the metal powder tends to be coarser as the angle of the injection holes 9 and 9a is decreased (in other words, the metal powder tends to be finer as the angle of the injection holes 9 and 9a is increased (closer to horizontal)). As a result, the particle size distributions of the metal ejected from the two spray nozzles 20A and 20B having different angles of the ejection holes 9 and 9a are different, and as shown in fig. 17, two peaks (average particle diameters μ 1 and μ 2) appear in the particle size distribution of the metal powder. In fig. 17, when the average particle diameter of the metal powder discharged from the spray nozzle 20A is μ 1, the average particle diameter of the metal powder discharged from the spray nozzle 20B is μ 2 smaller than μ 1. That is, as in the case described above in which the spraying conditions (1) are changed, metal powder having a wide range of particle sizes can be produced at one time as compared with the case in which the spraying conditions of the spray nozzles 20A and 20B are the same (see fig. 10).

Example 2 in fig. 16 corresponds to the spray nozzle 20A in fig. 12 in which the spray conditions (2) are changed from the comparative example (here, the spray nozzle 20B in the first embodiment), and the angle θ 9a of the spray hole 9a is reduced by 10 degrees from the angle θ 9 in the comparative example. In this case, the particle size of the metal powder produced by the spray nozzle 20A of example 2 was coarse compared to the comparative example.

Spraying conditions (3): diameter of injection hole 9 in multiple gas injection nozzles 2

Fig. 13 is a cross-sectional view of the periphery of the metal sprayer 230 in which the diameters of the ejection hole 9 of the gas ejection nozzle 2A of the spray nozzle 20A and the ejection hole 9 of the gas ejection nozzle 2B of the spray nozzle 20B are different from each other. In the metal sprayer 230 of the figure, unlike the first embodiment in which the diameter of the common ejection hole 9 of the two gas injection nozzles 2A and 2B is used, the diameters of the plurality of ejection holes 9 belonging to the gas injection nozzle 2A and the diameters of the plurality of ejection holes 9r belonging to the gas injection nozzle 2B are made different from each other. Specifically, the diameter of the plurality of ejection holes 9r belonging to the gas injection nozzle 2B is set larger than the diameter of the plurality of ejection holes 9 belonging to the gas injection nozzle 2A.

As shown in fig. 13, when the diameter of the plurality of ejection holes 9r belonging to the gas injection nozzle 2B (the spray nozzle 20B) is increased as compared with the diameter of the plurality of ejection holes 9 belonging to the gas injection nozzle 2A (the spray nozzle 20A), the gas amount of the gas injection nozzle 2B increases, and the grain size of the metal ejected from the spray nozzle 20B is made finer than the grain size ejected from the spray nozzle 20A. That is, the metal powder tends to be more finely pulverized as the diameter of the injection holes 9 and 9r increases (in other words, the metal powder tends to be more coarsely pulverized as the diameter of the injection holes 9 and 9r decreases). As a result, the particle size distributions of the metal ejected from the two spray nozzles 20A and 20B having different diameters of the ejection holes 9 and 9r are different, and two peaks (average particle diameters μ 1 and μ 2) appear in the particle size distribution of the metal powder as shown in fig. 17. In fig. 17, when the average particle diameter of the metal powder discharged from the spray nozzle 20A is μ 1, the average particle diameter of the metal powder discharged from the spray nozzle 20B is μ 2 smaller than μ 1. That is, as in the case described above in which the spraying conditions (1) are changed, metal powder having a wide range of particle sizes can be produced at one time as compared with the case in which the spraying conditions of the spray nozzles 20A and 20B are the same (see fig. 10).

Example 3 in fig. 16 corresponds to the spray nozzle 20B in fig. 13 in which the above-described spray conditions (3) are changed from the comparative example (here, the spray nozzle 20A in the first embodiment), and the diameter of the spray hole 9r is increased to a value 2 times the diameter of the spray hole 9 in the comparative example. In this case, the particle size of the metal powder produced by the spray nozzle 20B of example 3 was fine compared to the comparative example.

Spraying conditions (4): the number of the injection holes 9 in the plurality of gas injection nozzles 2

The metal spraying apparatus (not shown) under the spraying condition (4) differs from the first embodiment in which the number of the common ejection holes 9 in the two gas injection nozzles 2A and 2B is used, in that the number of the plurality of ejection holes 9 belonging to the gas injection nozzle 2A and the number of the plurality of ejection holes 9r belonging to the gas injection nozzle 2B are different. For example, there is a metal sprayer in which the number of the plurality of ejection holes 9 belonging to the gas injection nozzle 2B is set larger than the number of the plurality of ejection holes 9 belonging to the gas injection nozzle 2A. As described above, if the number of the plurality of ejection holes 9 belonging to the gas ejection nozzle 2B (the ejection nozzle 20B) is set to be larger than the number of the plurality of ejection holes 9 belonging to the gas ejection nozzle 2A (the ejection nozzle 20A), the gas amount of the gas ejection nozzle 2B increases, and the grain size of the metal ejected from the ejection nozzle 20B is made finer than the grain size ejected from the ejection nozzle 20A. That is, the metal powder tends to be more finely granulated as the number of the injection holes 9 increases (in other words, the metal powder tends to be more coarsely granulated as the number of the injection holes 9 decreases). As a result, the particle size distributions of the metal ejected from the two ejection nozzles 20A and 20B having different numbers of ejection holes 9 are different, and two peaks (average particle diameters μ 1 and μ 2) appear in the particle size distribution of the metal powder as shown in fig. 17. In fig. 17, when the average particle diameter of the metal powder discharged from the spray nozzle 20A is μ 1, the average particle diameter of the metal powder discharged from the spray nozzle 20B is μ 2 smaller than μ 1. That is, as in the case described above in which the spraying conditions (1) are changed, metal powder having a wide range of particle sizes can be produced at one time as compared with the case (see fig. 10) in which the spraying conditions of the spray nozzles 20A and 20B are the same.

Example 4 of fig. 16 is a plan corresponding to the spray nozzle 20B in the above example in which the spray conditions (4) are changed from the comparative example (here, the spray nozzle 20A of the first embodiment), and the number of the spray holes 9 is increased to a value 2 times the number of the spray holes 9 of the comparative example. In this case, the particle size of the metal powder produced by the spray nozzle 20B of example 4 was fine compared to the comparative example.

Spraying conditions (5): minimum bore diameter (flow bore diameter) of the molten metal nozzle 11

Fig. 14 is a sectional view of the periphery of the metal spraying apparatus 240 in which the minimum aperture 60A of the first molten metal nozzle 11A of the spray nozzle 20A and the minimum aperture 60B of the second molten metal nozzle 11B of the spray nozzle 20B are different from each other. The metal spray device 240 in this figure is different from the first embodiment using the smallest hole diameter common to both the first molten metal nozzles 11A and 11B in that the smallest hole diameter 60a of the first molten metal nozzle 11A and the smallest hole diameter 60B of the second molten metal nozzle 11B are different. Specifically, the minimum aperture 60a of the first molten metal nozzle 11A is set larger than the minimum aperture 60B of the second molten metal nozzle 11B. Further, although the diameters of the two molten steel nozzles 11A and 11B in fig. 14 are constant in the axial direction, the minimum diameters of the molten steel nozzles 11A and 11B can be set by providing a flow hole having a smaller diameter than the other portion in the flow hole, and the minimum diameter in this case coincides with the flow hole diameter.

As shown in fig. 14, when the minimum diameter 60A of the first molten metal nozzle 11A (spray nozzle 20A) is increased compared to the minimum diameter 60B of the second molten metal nozzle 11B (spray nozzle 20B) to increase the outflow per unit time, the particle size of the metal discharged from the spray nozzle 20A is coarsened compared to the particle size discharged from the spray nozzle 20B. That is, the metal powder tends to be coarser as the minimum pore sizes 60a and 60b are increased (in other words, the metal powder tends to be finer as the minimum pore sizes 60a and 60b are decreased). As a result, the particle size distributions of the metal ejected from the two different spray nozzles 20A and 20B having the smallest pore diameters 60A and 60B are different, and two peaks (average particle diameters μ 1 and μ 2) appear in the particle size distribution of the metal powder as shown in fig. 17. In fig. 17, when the average particle diameter of the metal powder discharged from the spray nozzle 20A is μ 1, the average particle diameter of the metal powder discharged from the spray nozzle 20B is μ 2 smaller than μ 1. That is, as in the case described above in which the spraying conditions (1) are changed, metal powder having a wide range of particle sizes can be produced at one time as compared with the case in which the spraying conditions of the spray nozzles 20A and 20B are the same (see fig. 10).

Example 5 in fig. 16 corresponds to the spray nozzle 20A in fig. 14 in which the above-described spray conditions (5) are changed from the comparative example (here, the spray nozzle 20B in the first embodiment), and the minimum pore diameter 60A (flow pore diameter) is increased to a value 1.5 times the value of the comparative example. In this case, the particle size of the metal powder produced by the spray nozzle 20A of example 5 was coarse compared to the comparative example.

Spraying conditions (6): shape of tip of molten metal nozzle 11

Fig. 15A is a cross-sectional view of the periphery of the metal spraying apparatus 250 in which the tip end shape 65A of the first molten metal nozzle 11A of the spray nozzle 20A and the tip end shape 65B of the second molten metal nozzle 11B of the spray nozzle 20B are different from each other, and fig. 15B is an enlarged view of the tip end portions of the first and second molten metal nozzles 11A, 11B. The metal spray device 250 in these figures is different from the first embodiment using the shape of the tip common to both the first molten metal nozzles 11A and 11B in that the tip shape 65a of the first molten metal nozzle 11A and the tip shape 65B of the second molten metal nozzle 11B are different. In the example of fig. 15A and 15B, the tip angles θ 65A and θ 65B of the molten metal nozzles 11A and 11B are different as the tip shapes. As shown in fig. 15B, the outer shape of the tip end portions of the molten steel nozzles 11A and 11B in the axial cross section of the tip end portions of the molten steel nozzles 11A and 11B at the tip end angles θ 65a and θ 65B of the molten steel nozzles 11A and 11B is defined by angles θ 65a and θ 65B with the central axes of the molten steel nozzles 11A and 11B (the central axes Cm1 and Cm2 of the molten steel nozzle insertion holes 12A and 12B). In the example of fig. 15A and 15B, the tip angle θ 65A of the first molten metal nozzle 11A is substantially 90 degrees and is set larger than the tip angle θ 65B of the second molten metal nozzle 11B.

As shown in fig. 15A, when the tip angle θ 65A of the first molten metal nozzle 11A (spray nozzle 20A) is increased compared to the tip angle θ 65B of the second molten metal nozzle 11B (spray nozzle 20B), the particle size of the metal sprayed from the spray nozzle 20A is coarsened compared to the particle size sprayed from the spray nozzle 20B. That is, the metal powder tends to be more coarsely grained as the tip angles θ 65a and θ 65b increase (in other words, the metal powder tends to be more finely grained as the tip angles θ 65a and θ 65b decrease). The particle size distributions of the metal ejected from the two spray nozzles 20A and 20B having different tip angles θ 65a and θ 65B are different, and as shown in fig. 17, two peaks (average particle diameters μ 1 and μ 2) appear in the particle size distribution of the metal powder. In fig. 17, when the average particle diameter of the metal powder discharged from the spray nozzle 20A is μ 1, the average particle diameter of the metal powder discharged from the spray nozzle 20B is μ 2 smaller than μ 1. That is, as in the case described above in which the spraying conditions (1) are changed, metal powder having a wide range of particle sizes can be produced at one time as compared with the case in which the spraying conditions of the spray nozzles 20A and 20B are the same (see fig. 10).

Example 6 in fig. 16 corresponds to the spray nozzle 20A in fig. 15A and 15B in which the above-described spray condition (6) is changed from the comparative example (here, the spray nozzle 20B of the first embodiment), and the tip angle θ 65A is increased by a value of 20 degrees from the value of the comparative example. In this case, the particle size of the metal powder produced by the spray nozzle 20A of example 6 was coarse compared to the comparative example.

As described above, in the present embodiment, the particle size distribution of the metal powder produced by the single-base gas atomizing device can be appropriately adjusted as needed by varying the spraying conditions of the plurality of spray nozzles 20A and 20B. That is, according to the present embodiment configured as described above, a plurality of peaks can be generated in the particle size distribution, and the metal powder having a wide particle size distribution can be manufactured at one time, so that it is possible to flexibly cope with a wide range of customer demands.

In the above example, the gas atomizing apparatus having two spray nozzles 20A and 20B is exemplified, and it is needless to say that the particle size distribution can be adjusted by appropriately changing the spray conditions even in the gas atomizing apparatus having three or more spray nozzles. For example, in a gas atomizing apparatus having three or more spray nozzles, if the spray conditions are set so that metal powder having different average particle diameters can be produced in each spray nozzle, as shown in fig. 18, the distribution can be adjusted to a gentle distribution in which the deviation of the particle size distribution can be suppressed by overlapping a plurality of peaks continuously.

Further, the case where the 6 spraying conditions (1) to (6) of the above example are changed, respectively, is described, but two or more of the 6 spraying conditions (1) to (6) may be appropriately combined as the spraying conditions of one spraying nozzle 20. That is, the spray conditions in the plurality of spray nozzles 20 can be different by at least one of the spray conditions of (1) to (6) above. That is, the plurality of molten metal nozzles 11 include a molten metal nozzle 11 having at least one of the smallest diameter and the tip shape different from the other molten metal nozzles 11, and the plurality of gas injection nozzles 2 may include a gas injection nozzle 2 having at least one of the injection pressure of the gas fluid, the angle of the injection hole, the diameter of the injection hole, and the number of injection holes different from the other gas injection nozzles 2.

< Others >

The present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the invention. For example, the present invention is not limited to the configuration having all the configurations described in the above embodiments, and a part of the configuration may be deleted. A part of the structure of one embodiment may be added to or replaced with the structure of another embodiment.

In the above embodiment, the case where two spray nozzles 20A and 20B are provided in one spray tank is described, but the number of spray nozzles 20A and 20B may be increased to three or more.

Further, the case where gas (gas fluid) is ejected from the gas ejection nozzles 2A and 2B will be described, but liquid such as water may be ejected. That is, the present invention may be applied to any nozzle that ejects a fluid. A

Description of the symbols

Cg 0-the center axis of the metal spraying apparatus 200, Cm1, Cm 2-the center axis of the molten metal nozzle insertion hole, Pg1, Pg 2-the center point of the bottom surface of the inverted cone, Tc1, Tc 2-the inclined center, 1-the dissolution tank, 2A, 2B-the gas injection nozzle, 3-the injection gas supply pipe, 4-the spray tank, 5-the collection hopper, 6-the exhaust gas, 7-the molten metal (molten metal), 8-the molten metal flow, 9-the injection hole, 10-the gas lance, 11A, 11B-the molten metal nozzle, 12-the molten metal nozzle insertion hole, 15-the fine particle, 20A, 20B-the spray nozzle, 21-the open end of the molten metal nozzle, 25-the gas injection direction (injection hole center axis), 26-the focus, 27-the molten metal flow-down region, 30A, 30B-the sealed gas jet nozzle, 31-the injection hole, 32-the slit, 35-the film-like jet stream (air curtain), 41-straight line (focal direction), 45-circular surface, 46-circular surface, 50-gas flow path, 70-gas injector, 90-circle formed by injection hole 9, 200-metal spraying device.

The claims (modification according to treaty clause 19)

(modified) a metal powder manufacturing apparatus, characterized in that,

the disclosed device is provided with:

a spray tank;

a plurality of spray nozzles for spraying molten metal into the spray tank,

the plurality of spray nozzles each include a molten metal nozzle for directing the molten metal into the spray tank and flowing down vertically, and a gas injection nozzle having a plurality of injection holes arranged around the molten metal nozzle for causing a gas flow to collide with the molten metal flowing down from the molten metal nozzle.

(modified) the metal powder manufacturing apparatus according to claim 1,

comprises a tank part for storing molten metal and a gas injector arranged below the tank part,

a plurality of the molten metal nozzles are provided downward from the bottom of the single tank portion,