JP2019031709A - Metal powder manufacturing apparatus and metal powder manufacturing method - Google Patents

Abstract

A metal powder production apparatus capable of producing a high-quality metal powder and a metal powder production method using the metal powder production apparatus are provided. A molten metal supply unit that discharges molten metal, a cylindrical body that is installed below the molten metal supply unit, and a flow of cooling liquid that cools the molten metal discharged from the molten metal supply unit. Is a metal powder manufacturing apparatus 10 having a cooling liquid layer forming part 36 that forms the gas along the inner peripheral surface of the cylindrical body. The cooling liquid layer forming unit 36 includes a frame body 38 that changes the flow of the cooling liquid from the inner peripheral surface 33 toward the inner side in the radial direction to the direction of flowing along the inner peripheral surface 33 of the cylindrical body 32. [Selection] Figure 1

Description

  The present invention relates to a metal powder production apparatus and a metal powder production method.

  For example, as shown in Patent Document 1, a metal powder manufacturing apparatus that manufactures metal powder using a so-called gas atomization method and a manufacturing method using the apparatus are known. The conventional apparatus includes a molten metal supply container that discharges molten metal, a cylinder installed below the molten metal supply container, and a flow of a coolant that cools the molten metal discharged from the molten metal supply unit. And a cooling liquid layer forming part formed along the inner peripheral surface of the cylindrical body.

  The cooling liquid layer forming unit sprays the cooling liquid toward the tangential direction of the inner peripheral surface of the cooling cylinder, and causes the cooling liquid to flow down while swirling along the inner peripheral surface of the cooling container. Is forming. By using the cooling liquid layer, it is expected that the droplets can be rapidly cooled to produce a highly functional metal powder.

  However, in the conventional apparatus, even if the cooling liquid is sprayed toward the tangential direction of the inner peripheral surface of the cooling cylinder, the cooling liquid is reflected by the inner peripheral surface of the cylindrical body and is radially directed from the inner peripheral surface. An inward flow occurs. For this reason, in the conventional apparatus, it is difficult to form a cooling liquid layer having a uniform thickness by forming waves on the surface along the inner peripheral surface of the cylindrical body. There was a problem that it was difficult to produce a metal powder having a uniform thickness. In particular, when the flow rate of the cooling liquid is increased or the pressure of the pump that pushes out the cooling liquid is increased to increase the speed of the cooling liquid, the tendency becomes stronger.

Japanese Patent Laid-Open No. 11-80812

  This invention is made | formed in view of such an actual condition, The objective is to provide the metal powder manufacturing apparatus which can manufacture a high quality metal powder, and the manufacturing method of a metal powder using the same.

In order to achieve the above object, a metal powder production apparatus according to the present invention comprises:
A molten metal supply unit for discharging the molten metal;
A cylinder installed below the molten metal supply unit;
A cooling liquid layer forming unit for forming a flow of a cooling liquid for cooling the molten metal discharged from the molten metal supply unit along an inner peripheral surface of the cylindrical body,
The cooling liquid layer forming section includes a frame body that changes the flow of the cooling liquid from the inner peripheral surface inward in the radial direction to a direction of flowing along the inner peripheral surface of the cylindrical body. .

In order to achieve the above object, a method for producing a metal powder according to the present invention comprises:
Forming a flow of the coolant along the inner peripheral surface of the cylindrical body installed below the molten metal supply unit;
Discharging the molten metal from the molten metal supply unit toward the flow of the cooling liquid, and a method for producing a metal powder comprising:
The flow of the coolant from the inner peripheral surface toward the inner side in the radial direction is applied to the frame body provided on the upper portion of the cylindrical body, and is changed to the direction of flowing along the inner peripheral surface of the cylindrical body. It is characterized by.

  In the metal powder manufacturing apparatus and the metal powder manufacturing method according to the present invention, the frame body is provided on the upstream side of the position where the molten metal discharged from the molten metal supply unit contacts the coolant. For this reason, it is possible to suppress the surface wave generated by the flow of the coolant from the inner peripheral surface toward the inner side in the radial direction and to change the flow direction along the inner peripheral surface of the cylindrical body. Therefore, even when the flow rate of the coolant is increased or the speed of the coolant is increased, the waves on the flow surface of the coolant flowing radially inward from the inner periphery along the inner periphery of the cylinder are suppressed. And it becomes easy to form the cooling liquid layer of uniform thickness along the inner peripheral surface of a cylinder, and it becomes possible to produce a high quality metal powder.

Preferably, the inner diameter of the frame is smaller than the inner diameter of the inner peripheral surface of the cylindrical body,
A gap between the frame body and the inner peripheral surface constitutes a coolant discharge part for allowing the coolant to flow along the inner peripheral surface. With this configuration, it is easy to form a cooling liquid layer having a uniform thickness along the inner peripheral surface of the cylindrical body even when the flow rate of the cooling liquid is increased or the speed of the cooling liquid is increased. become.

  The inner diameter of the frame body may be substantially the same toward the lower end in the axial direction of the frame body, but may be configured to be tapered. By increasing the inner diameter of the frame in a tapered shape toward the lower end in the axial direction, a force in the direction of pressing the coolant toward the inner peripheral surface acts, and a uniform thickness along the inner peripheral surface of the cylinder It becomes easy to form the cooling liquid layer.

  Preferably, the frame is attached above the cylinder. By comprising in this way, it becomes easy to arrange | position a frame to the upstream of the position where the molten metal discharged from the molten metal supply part contacts a cooling fluid.

  Preferably, the cooling liquid layer forming unit includes a spiral flow forming unit that causes the cooling liquid to collide spirally toward the frame. The spiral flow forming portion is formed, for example, by attaching a nozzle for injecting a coolant toward the tangential direction of the inner peripheral surface of the cylinder. A cooling liquid layer having a uniform thickness along the inner peripheral surface of the cylindrical body by attaching a frame inside the position where the cooling liquid is discharged from the spiral flow forming portion toward the tangential direction of the inner peripheral surface of the cylindrical body It becomes easy to form.

FIG. 1 is a schematic cross-sectional view of a metal powder manufacturing apparatus according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a metal powder manufacturing apparatus according to another embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of a metal powder manufacturing apparatus according to still another embodiment of the present invention.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

First Embodiment As shown in FIG. 1, a metal powder manufacturing apparatus 10 according to an embodiment of the present invention is a metal made up of a large number of metal particles by pulverizing a molten metal 21 by an atomizing method (gas atomizing method). An apparatus for obtaining a powder. The apparatus 10 includes a molten metal supply unit 20 and a cooling unit 30 disposed below the metal supply unit 20 in the vertical direction. In the drawings, the vertical direction is a direction along the Z axis.

  The molten metal supply unit 20 includes a heat-resistant container 22 that stores the molten metal 21. A heating coil 24 is disposed on the outer periphery of the heat resistant container 22, and the molten metal 21 accommodated in the container 22 is heated and maintained in a molten state. A discharge port 23 is formed at the bottom of the container 22, from which the molten metal 21 is discharged as a dropped molten metal 21 a toward the inner peripheral surface 33 of the cylindrical body 32 constituting the cooling unit 30. It has become.

  A gas injection nozzle 26 is disposed on the outer peripheral portion of the outer bottom wall of the container 22 so as to surround the discharge port 23. The gas injection nozzle 26 is provided with a gas injection port 27. High-pressure gas is injected from the gas injection port 27 toward the dropped molten metal 21 a discharged from the discharge port 23. The high-pressure gas is injected obliquely downward from the entire circumference of the molten metal discharged from the discharge port 23, and the dropped molten metal 21a becomes a large number of liquid droplets, and the inside of the cylinder 32 along the gas flow. Carried to the surface.

  The molten metal 21 may contain any element. For example, a metal containing at least one of Ti, Fe, Si, B, Cr, P, Cu, Nb, and Zr can be used. These elements are highly active, and the molten metal 21 containing these elements is easily oxidized to form an oxide film by contact with air for a short period of time, and it is difficult to miniaturize. . As described above, the metal powder manufacturing apparatus 10 can easily pulverize even the molten metal 21 that is easily oxidized by using an inert gas as the gas injected from the gas injection port 27 of the gas injection nozzle 26. it can.

  The gas injected from the gas injection port 27 is preferably an inert gas such as nitrogen gas, argon gas or helium gas, or a reducing gas such as ammonia decomposition gas. However, if the molten metal 21 is a metal that is difficult to oxidize. Air may be used.

  In the present embodiment, the axis O of the cylindrical body 32 is inclined at a predetermined angle θ1 with respect to the vertical line Z. Although it does not specifically limit as predetermined angle (theta) 1, Preferably, it is 5-45 degree | times. By setting it as such an angle range, it becomes easy to discharge the dripping molten metal 21a from the discharge outlet 23 toward the cooling liquid layer 50 formed in the inner peripheral surface 33 of the cylindrical body 32.

  The dropped molten metal 51 discharged to the cooling liquid layer 50 collides with the cooling liquid layer 50, and is further divided, refined, cooled and solidified, and becomes a solid metal powder. A discharge part 34 is provided below the axis O of the cylindrical body 32 so that the metal powder contained in the coolant layer 50 can be discharged together with the coolant to the outside. The metal powder discharged together with the cooling liquid is separated from the cooling liquid and taken out in an external storage tank or the like. The cooling liquid is not particularly limited, but cooling water is used.

  In the present embodiment, a frame body 38 as a coolant layer forming part is provided on the upper portion of the cylindrical body 32 in the direction of the axis O. The frame 38 is attached to the upper part of the cylindrical body 32 by an attachment flange 39 formed integrally therewith. A method for attaching the frame body 38 is not particularly limited, and the frame body 38 may be formed integrally with the cylinder body 32. The frame body 38 has an inner diameter smaller than the inner diameter of the inner peripheral surface 33 of the cylindrical body 32, and is arranged concentrically with the inner peripheral surface of the cylindrical body 32. In the present embodiment, the inner peripheral surface of the frame body 38 and the inner peripheral surface of the cylindrical body 32 are arranged substantially in parallel.

  In the upper position of the cylinder 32 corresponding to the frame 38, a cooling liquid layer forming portion 36 is formed. On the inner peripheral side of 36, a nozzle hole 37a that opens toward the inside of the cylindrical body 32 is formed continuously (or intermittently) along the circumferential direction. The nozzle hole 37a is formed to face the frame body 38 with a predetermined gap. The width of the circumferential gap between the frame body 38 and the inner peripheral surface 33 (the radial width of the coolant discharge part 52) is not particularly limited, but is determined in relation to the thickness of the coolant layer 50. The width of the circumferential gap between the frame body 38 and the inner peripheral surface 33 may be smaller than the thickness of the coolant layer 50.

  The axial length L1 of the frame 38 may be a length that covers the nozzle hole 37a, and the liquid level of the coolant layer 50 having a sufficient axial length L0 on the inner peripheral surface 33 of the cylindrical body 32. Is exposed. The axial length L0 of the coolant layer 50 exposed on the inner side is preferably 5 to 500 times longer than the axial length L1 of the frame 38. Moreover, the internal diameter of the inner peripheral surface 33 of the cylindrical body 32 is not particularly limited, but is preferably 50 to 500 mm.

  In the present embodiment, the gap between the frame 38 and the inner peripheral surface 33 of the cylindrical body 32 constitutes a coolant discharge part 52 for flowing the coolant along the inner peripheral surface 33. In the present embodiment, a nozzle 37 serving as a spiral flow forming portion is connected to the upper portion of the cylindrical body 32 in the Z-axis direction. By connecting the nozzle 37 in the tangential direction of the cylindrical body 32, the nozzle 37 flows from the nozzle 37 into the cylindrical body 32 through the nozzle hole 37 a toward the inner side in the radial direction from the inner peripheral surface 33. It collides with the surface and passes through the coolant discharge part 52 so that it flows in the direction along the inner peripheral surface 33 of the cylinder 32.

  The cooling liquid flowing along the inner peripheral surface 33 of the cylindrical body 32 becomes a spiral flow due to the rotational flow and gravity of the cooling liquid continuously supplied from the nozzle 37, thereby forming the cooling liquid layer 50. The dropped molten metal 21a shown in FIG. 1 is incident on the inner peripheral liquid surface of the cooling liquid layer 50 formed in this way, and the dropped molten metal 21a is combined with the cooling liquid inside the spirally flowing cooling liquid layer 50. Flowed and cooled.

  In the metal powder manufacturing apparatus 10 and the metal powder manufacturing method using the metal powder manufacturing apparatus 10 according to the present embodiment, upstream of the position where the dropped molten metal 21 a discharged from the discharge port 23 of the metal supply unit 20 contacts the cooling liquid layer 50. A frame 38 is provided on the side. For this reason, the flow of the coolant from the inner peripheral surface 33 toward the inner side in the radial direction through the nozzle hole 37 a can be changed to the direction of flowing along the inner peripheral surface 33 of the cylindrical body 32. Therefore, even when the flow rate of the cooling liquid is increased or the speed of the cooling liquid is increased, it is easy to form the cooling liquid layer 50 having a uniform thickness along the inner peripheral surface of the cylindrical body 32. Quality metal powder can be produced.

  Further, the inner diameter of the frame body 38 is smaller than the inner diameter of the inner peripheral surface 33 of the cylindrical body 32, and the gap between the frame body 38 and the inner peripheral surface 33 allows the coolant to flow along the inner peripheral surface 33. The coolant discharge unit 52 is configured. With this configuration, even when the flow rate of the cooling liquid is increased or the speed of the cooling liquid is increased, the cooling liquid layer 50 having a uniform thickness is formed along the inner peripheral surface of the cylindrical body 32. Becomes easier.

  Further, in the present embodiment, the frame body 38 is attached above the axis O of the cylindrical body 32. With this configuration, the frame body 38 can be easily arranged on the upstream side of the position where the molten metal discharged from the metal supply unit 20 contacts the coolant.

  Furthermore, in this embodiment, the inner peripheral surface 33 of the cylindrical body 32 is attached by attaching the frame body 38 inside the position where the coolant is discharged from the nozzle 37 toward the tangential direction of the inner peripheral surface 33 of the cylindrical body 2. It is easy to form the cooling liquid layer 50 composed of a spiral flow having a uniform thickness.

Second Embodiment As shown in FIG. 2, the metal powder manufacturing apparatus 110 and the metal powder manufacturing method according to the second embodiment of the present invention are the same as and common to the first embodiment except for the following. The members are denoted by common member names and symbols, and the description of the common portions is partially omitted.

  In the present embodiment, the metal powder manufacturing apparatus 110 includes a flow path box 136 that is continuous in the circumferential direction as a coolant layer forming unit in the cooling unit 130. The flow path box 136 is attached to an upper portion of the cylindrical body 32 in the direction of the axis O. A flow path continuous in the circumferential direction is formed inside the flow path box 136. A plurality of nozzles 137 are connected to the upper part (or lower part) of the flow path box 136 in the direction of the axis O. These nozzles 137 are connected to the outer periphery of the flow path box 136 so as to be inclined with respect to the axis O so as to form a spiral coolant flow in the flow path box 136. May be.

  Alternatively, these nozzles 137 may be connected in parallel to the axis O on the outer peripheral side at the upper part (or lower part) of the flow path box 136. Alternatively, the nozzle 137 may be connected to the outer peripheral surface of the flow path box 136 so as to form a spiral coolant flow in the flow path box 136.

  A frame body 138 (corresponding to the frame body 38 shown in FIG. 1) is formed integrally with the flow path box 136 on the inner peripheral side of the flow path box 136. The frame body 138 has an inner diameter smaller than the inner peripheral surface 33 of the cylindrical body 32, and a circumferential clearance between the frame body 138 and the inner peripheral surface 33 becomes the coolant discharge part 52. In the present embodiment, the coolant discharge part 52 can be formed by forming a hole that is discontinuous in the circumferential direction (or a hole that is continuous in the circumferential direction) on the lower inner peripheral side of the flow path box 136. The outer diameter of the coolant discharge part 52 matches the inner diameter of the inner peripheral surface 33, and the inner diameter of the coolant discharge part 52 matches the inner diameter of the frame body 138.

  In the present embodiment, the flow of the cooling liquid flowing out from the cooling liquid discharge part 52 by the flow of the cooling water entering the inside of the flow path box 136 from the nozzle 137 becomes a spiral flow along the inner peripheral surface 33, A cooling liquid layer 50 is formed. Alternatively, the flow of the cooling liquid flowing out from the cooling liquid discharge unit 52 becomes a flow parallel to the axis O along the inner peripheral surface 33, thereby forming the cooling liquid layer 50.

  In the metal powder manufacturing apparatus 110 according to the present embodiment and the metal powder manufacturing method using the same, upstream of the position where the dripped molten metal 21a discharged from the discharge port 23 of the metal supply unit 20 contacts the coolant layer 50. A frame body 138 is provided on the side. For this reason, the flow of the cooling liquid toward the inside in the radial direction inside the flow path box 136 can be changed by the frame body 138 to the direction of flowing along the inner peripheral surface 33 of the cylindrical body 32. Therefore, even when the flow rate of the cooling liquid is increased or the speed of the cooling liquid is increased, it is easy to form the cooling liquid layer 50 having a uniform thickness along the inner peripheral surface of the cylindrical body 32. Quality metal powder can be produced.

Third Embodiment As shown in FIG. 3, a metal powder manufacturing apparatus 210 according to an embodiment of the present invention is the same as the first embodiment or the second embodiment except for the following, and is a common member. Are given common member names and symbols, and a part of the description of the common parts is omitted.

  In the embodiment shown in FIGS. 1 to 2, the inner diameter of the frame 38 or 138 is substantially the same toward the lower end of the frame 38 or 138 in the direction of the axis O, but in the present embodiment, in the cooling unit 230. The lower tip 238a of the frame 238 is configured to be tapered. In the present embodiment, there is a discontinuous gap (may be continuous) in the circumferential direction between the lower tip 238a of the frame 238 constituting the inner peripheral surface of the flow path box 236 and the inner peripheral surface 33 of the cylindrical body 32. Then, the coolant discharge unit 52 is obtained. A plurality of nozzles 237 are connected to the upper part (or the lower part) of the flow path box 236 in the axis O direction.

  The taper angle θ2 with respect to the axis O of the lower end portion 238a of the frame 238 is not particularly limited, but is preferably 5 to 45 degrees. By increasing the inner diameter of the lower front end portion 238a of the frame 238 in a tapered manner toward the lower end in the axial direction, the force in the direction of pressing the coolant flowing out from the coolant discharge portion 52 toward the inner peripheral surface 33 is increased. This makes it easy to form the cooling liquid layer 50 having a uniform thickness along the inner peripheral surface 33 of the cylindrical body 32.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

EXAMPLE Using the metal powder production apparatus 10 shown in FIG. 1, Fe-Si-B (Experiment No. 6), Fe-Si-Nb-B-Cu (Experiment No. 7), Fe-Si-B-P-Cu (Experiment No. 8), Fe-Nb-B (Experiment No. 9), and Fe-Zr-B (Experiment No. 10) were produced.

  In each experiment, the dissolution temperature was 1500 ° C., the injection gas pressure was 5 MPa, the gas type argon was constant, and the spiral water flow condition was a pump pressure of 7.5 kPa. In the examples, metal powder having an average particle diameter of about 25 μm could be produced. The average particle size was determined by measurement using a dry particle size distribution measuring device (HELLOS). Moreover, the crystal analysis of the metal powder produced by experiment number 6-10 was evaluated by the powder X-ray diffraction method. The magnetic properties of the metal powder were measured by measuring the coercive force (Oe) with an Hc meter. The results are shown in Table 1. Further, the thickness of the coolant layer 50 was 30 mm, and it was observed that the variation in the axis O direction was small.

A metal powder (experiment numbers 1 to 5) was produced in the same manner as in the example using the same metal powder production apparatus as in the example except that the comparative example frame 38 was not provided, and the same evaluation was performed. . The results are shown in Table 1. It was observed that the thickness of the cooling liquid layer 50 was 30 mm and the variation was large in the direction of the axis O.

  Comparing the examples of Table 1 and the comparative example, the magnetic properties were improved and the amorphousness was improved. This is considered to be due to the fact that a uniform cooling effect is obtained by suppressing the wave of the surface of the spiral water flow, and there are few powders that are insufficiently cooled. Further, when the crystal analysis of the metal powder was performed by powder X-ray diffraction, there was a comparative example having a peak due to the crystal. As for the magnetic properties of the metal powder, it can be seen that the comparative example has a coercive force larger than that of the example and it can be confirmed that the example is superior, so that a more uniform cooling effect is obtained.

  Comparing the above comparative example and the embodiment, by providing the frame body 38, even in a state where the pump pressure is high, the waves on the flow surface of the coolant flowing from the inner peripheral surface to the inside in the radial direction are suppressed and rectified. As a result, a uniform cooling effect was obtained, and amorphousness was confirmed even for a composition that could not be produced in the past, and the magnetic properties could be improved.

DESCRIPTION OF SYMBOLS 10,110,210 ... Metal powder manufacturing apparatus 20 ... Molten metal supply part 21 ... Molten metal 22 ... Container 23 ... Discharge port 24 ... Heating coil 26 ... Gas injection nozzle 27 ... Gas injection port 30, 130, 230 ... Cooling part 32 ... Tube 33 ... Inner peripheral surface 34 ... Discharge part 37 ... Nozzle 37a ... Nozzle hole 136, 236 ... Channel box 137, 237 ... Nozzle 38, 138, 238 ... Frame 238a ... Frame tip 39 ... Mounting flange 50 ... Coolant layer 52 ... Coolant discharge part

Claims (6)

A molten metal supply unit for discharging the molten metal;
A cylinder installed below the molten metal supply unit;
A cooling liquid layer forming unit for forming a flow of a cooling liquid for cooling the molten metal discharged from the molten metal supply unit along an inner peripheral surface of the cylindrical body,
The cooling liquid layer forming section includes a frame body that changes the flow of the cooling liquid from the inner peripheral surface inward in the radial direction to a direction of flowing along the inner peripheral surface of the cylindrical body. Metal powder production equipment. The inner diameter of the frame is smaller than the inner diameter of the inner peripheral surface of the cylinder,
The metal powder manufacturing apparatus according to claim 1, wherein a gap between the frame body and the inner peripheral surface constitutes a coolant discharge part for allowing the coolant to flow along the inner peripheral surface.   The metal powder manufacturing apparatus according to claim 1 or 2, wherein an inner diameter of the frame body is configured to be increased in a tapered shape toward an axial lower end of the frame body.   The metal powder manufacturing apparatus according to any one of claims 1 to 3, wherein the frame is attached above the cylindrical body.   The metal powder manufacturing apparatus according to any one of claims 1 to 4, wherein the cooling liquid layer forming unit includes a spiral flow forming unit that spirally collides the cooling liquid toward the frame. Forming a flow of the coolant along the inner peripheral surface of the cylindrical body installed below the molten metal supply unit;
Discharging the molten metal from the molten metal supply unit toward the flow of the cooling liquid, and a method for producing a metal powder comprising:
The flow of the coolant from the inner peripheral surface toward the inner side in the radial direction is applied to the frame body provided on the upper portion of the cylindrical body, and is changed to the direction of flowing along the inner peripheral surface of the cylindrical body. A method for producing a metal powder characterized by the above.

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