Metal powder manufacturing apparatus and method for manufacturing metal powder

Abstract

The metal powder manufacturing apparatus (10) of the present application has a molten metal supply portion (20) that discharges molten metal (21), a cylinder (32) that forms a cooling liquid layer (50) that cools the molten metal (21) on an inner peripheral surface (33), and a cooling liquid guide portion (36) that supplies cooling liquid to the inside of an upper portion of the cylinder (32). The inner peripheral surface (33) of the inside of the upper portion of the cylinder (32) is substantially elliptical in shape.

Description

TECHNICAL FIELD

[0001] The present application relates to a metal powder manufacturing apparatus and a method of manufacturing metal powder. BACKGROUND

[0002] For example, as shown in Patent Literature 1, a metal powder manufacturing apparatus using so-called gas atomization method and a manufacturing method using the apparatus are known. The existing apparatus has a molten metal supply container which discharges molten metal, a cylinder body provided below the molten metal supply container, and a cooling liquid leading-out portion which forms a flow of cooling liquid which cools the molten metal discharged from the molten metal supply portion on the inner peripheral surface of the cylinder body.

[0003] The cooling liquid leading-out portion forms a cooling liquid layer by spraying the cooling liquid toward a tangent direction of the inner peripheral surface of the cooling cylinder body and making the cooling liquid flow down while rotating in a circular shape on the inner peripheral surface of the cooling container. It is expected that the rapid cooling of the droplet can be achieved by using the cooling liquid layer, and a metal powder with high functionality can be manufactured.

[0004] However, in the existing manufacturing of metal powder, the rapid cooling of the droplet is sometimes insufficient, and an apparatus and a method which can manufacture a metal powder with higher quality are sought.

[0005] PRIOR ART DOCUMENT

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 11-80812 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] The present application is made in view of such actual circumstances, and aims to provide a metal powder manufacturing apparatus and a method of manufacturing metal powder which can manufacture a metal powder with higher quality.

[0010] TECHNICAL SOLUTION FOR SOLVING THE PROBLEMS

[0011] In order to achieve the above object, the present application provides a metal powder manufacturing apparatus characterized by comprising:

[0012] a molten metal supply portion which discharges molten metal;

[0013] a cylinder body which forms a cooling liquid layer which cools the molten metal on the inner peripheral surface; and

[0014] a cooling liquid leading-out portion which supplies the cooling liquid to the cylinder body,

[0015] the inner peripheral surface of the upper portion inside of the cylinder body is substantially elliptical.

[0016] In the metal powder manufacturing apparatus of the present application, a cooling liquid layer flowing in an approximately elliptical spiral shape can be formed along the inner peripheral surface of the cylinder. By spraying the molten metal droplets to this cooling liquid layer, the molten metal droplets can be rapidly cooled. The flow of the cooling liquid in the elliptical spiral shape is faster on the short diameter side of the ellipse and slower on the long diameter side, and the molten metal droplets sprayed to the cooling liquid layer flow in the cooling liquid layer while changing the flow rate together with the cooling liquid.

[0017] By making the molten metal droplets flow in the cooling liquid layer while changing the flow rate together with the cooling liquid, it is considered that the film of the vapor around the molten metal droplets generated after the molten metal droplets contact the cooling liquid is easily peeled off from the molten metal droplets, and the rapid cooling effect of the molten metal droplets in the cooling liquid layer is improved. By rapidly cooling the molten metal droplets in this way, a metal powder having a fine particle diameter and excellent amorphous properties or magnetic properties can be obtained.

[0018] Preferably, the cooling liquid leading portion has a cooling liquid discharge port discharging the cooling liquid supplied from the outside of the cylinder in a manner of flowing in a spiral track along the inner peripheral surface from the upper portion of the cylinder. By being configured in this way, the cooling liquid layer can be formed in an elliptical spiral shape from the cooling liquid discharge port from the upper portion of the cylinder along the inner peripheral surface toward the lower portion, the rapid cooling effect of the molten metal droplets is improved, and a metal powder having a fine particle diameter and excellent amorphous properties or magnetic properties can be obtained.

[0019] Preferably, the cooling liquid discharge port is formed in a substantially elliptical shape over the circumference of the cylinder. The cooling liquid discharge port can be formed continuously over the circumference of the cylinder, or a reinforcing member or the like can be provided to the cooling liquid discharge port and the cooling liquid discharge port can be formed discontinuously over the circumference of the cylinder. By forming the cooling liquid discharge port over the circumference of the cylinder, the cooling liquid layer of the cooling liquid flowing in an elliptical spiral shape along the inner peripheral surface of the cylinder can be easily formed.

[0020] Preferably, the cooling liquid leading portion has a frame changing the flow of the cooling liquid from the outside to the inside to the flow along the inner peripheral surface of the cylinder, and the frame has an inner frame piece having a substantially elliptical shape with a smaller diameter than the inner peripheral surface of the cylinder. By being configured in this way, a cooling liquid discharge port having a substantially elliptical shape can be formed between the inner frame piece and the inner peripheral surface of the cylinder. As a result, the cooling liquid flowing in an elliptical spiral shape can be discharged from the cooling liquid discharge port along the inner peripheral surface of the cylinder.

[0021] Preferably, the frame is disposed inside the cylinder, an inside space into which the cooling liquid enters from the outside of the cylinder is formed, and the inside space is formed in a substantially elliptical shape along the inner peripheral surface. By being configured in this way, the cooling liquid can be formed to flow in an elliptical shape along the inner peripheral surface in the inside space. By flowing along the inner peripheral surface, the cooling liquid is discharged toward the lower portion along the axis core of the cylinder, and thus the cooling liquid layer in an elliptical spiral shape can be smoothly formed along the inner peripheral surface.

[0022] Preferably, the cooling liquid leading-out portion has an outer side forming member that forms an outer side space in which the cooling liquid is temporarily stored, the outer side forming member being arranged on the outer side of the cylinder, and the outer side space being formed in a substantially elliptical shape. With this configuration, the cooling liquid is led into the inner side of the cylinder while rotating in an elliptical shape in the outer side space, and a cooling liquid layer of the cooling liquid flowing in an elliptical spiral along the inner peripheral surface of the cylinder is easily formed smoothly.

[0023] Preferably, a cooling liquid discharge port is formed between the inner peripheral surface of the cylinder and the inner frame piece. The inner peripheral surface of the cylinder can also be the inner peripheral surface of the cylinder auxiliary piece. Preferably, the lower end of the passage portion that connects the outer side space and the inner side space of the cooling liquid leading-out portion is arranged above along the shaft core.

[0024] Preferably, the center of the elliptical shape formed by the inner peripheral surface is offset in a manner that tilts with respect to the vertical line toward the lower portion of the cylinder. With this configuration, the cooling liquid of the cooling liquid layer formed along the inner peripheral surface flows while drawing an elliptical spiral orbit and also tilting with respect to the vertical direction. Therefore, the distance of the elliptical spiral of the cooling liquid flow can be extended. In addition, by ejecting the molten metal toward the lower portion of the vertical direction, the spatter of the molten metal easily enters the cooling liquid layer without hindering the flow of the cooling liquid, and the spatter is easily cooled smoothly.

[0025] Preferably, in the elliptical shape formed by the inner peripheral surface, the ratio of the minor axis to the major axis is 1.04 or more and 3.00 or less. With this configuration, the flow rate of the cooling liquid is easily changed and a cooling liquid layer of uniform thickness is formed.

[0026] A ring can also be formed in a substantially elliptical shape along the inner peripheral surface of the lower portion of the cylinder. With this configuration, the ring controls the flow of the cooling liquid toward the direction along the shaft core of the cylinder, and the thickness of the cooling liquid layer of the cooling liquid flowing in an elliptical spiral along the inner peripheral surface of the cylinder is easily controlled to a constant thickness.

[0027] In addition, to achieve the above object, the present application provides a method of manufacturing a metal powder, comprising:

[0028] a step of forming a cooling liquid layer of which the flow rate is changed along the inner peripheral surface of the cylinder;

[0029] a step of discharging molten metal toward the cooling liquid layer from a molten metal supply portion; and

[0030] a step of causing the molten metal to flow together with the cooling liquid while changing the flow rate.

[0031] With this configuration, the rapid cooling effect of the spatter of the molten metal is improved, and a metal powder with good amorphousness or magnetic properties even for a small particle diameter can be obtained.

[0032] Preferably, the cooling liquid is caused to flow along the inner circumferential surface in a substantially elliptical spiral to form the cooling liquid layer. By so configuring, the molten metal droplets flow along the inner circumferential surface while changing the flow rate together with the cooling liquid, and it is possible to improve the rapid cooling effect of the molten metal droplets. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1A is a schematic cross-sectional view of a metal powder manufacturing apparatus according to an embodiment of the present application.

[0034] Figure 1B is a schematic cross-sectional view of a main portion of the metal powder manufacturing apparatus shown in Figure 1A

[0035] Figure 1C is an enlarged cross-sectional view of a main portion of the metal powder manufacturing apparatus shown in Figure 1A

[0036] Figure 2A is a schematic view of the flow of the cooling liquid in the metal powder manufacturing apparatus shown in Figure 1A

[0037] Figure 2B is a schematic view of the flow of the cooling liquid viewed from the vertical direction. Figure 2A

[0038] Figure 3A is a schematic view showing the structure of the cylinder of the metal powder manufacturing apparatus shown in Figure 1A

[0039] Figure 3B is a schematic view showing the structure of a modification example of the cylinder shown in Figure 1A

[0040] Figure 4 is a schematic cross-sectional view of a metal powder manufacturing apparatus according to another embodiment of the present application.

[0041] Figure 5A is a schematic view of the flow of the cooling water in the existing metal powder manufacturing apparatus viewed from the side.

[0042] Figure 5B is a schematic view of the flow of the cooling water shown in Figure 5A DETAILED DESCRIPTION

[0043] Hereinafter, the present application will be described based on the embodiments shown in the drawings.

[0044] First Embodiment

[0045] As​​​​​​​Figure 1A As shown in the drawing, the metal powder manufacturing apparatus 10 of an embodiment of the present application is an apparatus for obtaining a metal powder composed of a plurality of metal particles by atomizing a molten metal 21 by an atomization method (a gas atomization method). The apparatus 10 has a molten metal supply portion 20 and a cooling portion 30 disposed below the vertical direction of the metal supply portion 20. In the drawing, the vertical direction is the direction along the Z axis.

[0046] The molten metal supply portion 20 has a heat-resistant container 22 that accommodates 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 interior of the container 22 is heated by the heating coil 24 and maintained in a molten state. A molten metal discharge port 23 is formed in the bottom portion of the container 22, and from this, the molten metal 21 is discharged as a droplet molten metal 21a toward the inner peripheral surface 33 of a cylindrical body 32 that constitutes the cooling portion 30.

[0047] A gas nozzle 26 is disposed on the outer side portion of the outer bottom wall of the container 22 in a manner so as to surround the molten metal discharge port 23. The gas nozzle 26 is provided with a gas injection port 27. From the gas injection port 27, high-pressure gas is injected toward the droplet molten metal 21a discharged from the molten metal discharge port 23. The high-pressure gas is obliquely injected in a downward direction from all around the molten metal discharged from the molten metal discharge port 23, and the droplet molten metal 21a becomes a plurality of liquid droplets and is carried along the flow of the gas toward the inner peripheral surface 33 of the upper inner side of the cylindrical body 32.

[0048] The molten metal 21 can also contain any element, and for example, an element containing at least any one of Ti, Fe, Si, B, Cr, P, Cu, Nb, and Zr can also be used. These elements have high activity, and the molten metal 21 containing these elements is easily oxidized by contact with air for a short time, forms an oxide film, and is not easily refined. The metal powder manufacturing apparatus 10 uses an inert gas as the gas injected from the gas injection port 27 of the gas nozzle 26 as described above, and thus even if the molten metal 21 is a metal that is easily oxidized, powderization can be easily performed.

[0049] As the gas injected from the gas injection port 27, an inert gas such as nitrogen, argon, helium, or a reducing gas such as ammonia decomposition gas is preferable, but if the molten metal 21 is a metal that is not easily oxidized, air can also be used.

[0050] In the present embodiment, Figure 1A The inner peripheral surface 33 of at least the upper inner side of the cylindrical body 32 (the portion to which the droplet molten metal 21a is supplied) shown in the drawing has a substantially elliptical shape in a cross section that is inclined at an angle θ1 with respect to the axis core O of the cylindrical body 32 (for example, a cross section that is substantially perpendicular to the Z axis). If the axis core O of the cylindrical body 32 is inclined at an angle θ2 with respect to the Z axis, the angle θ1 can be expressed as θ1 = (90 degrees - θ2).

[0051] On a cross section inclined at an angle θ1 relative to the core O of the cylinder 32, the major axis of the ellipse of the inner circumferential surface 33 is preferably aligned with the direction of inclination of the core O of the cylinder 32 relative to the Z-axis (vertical line). That is, the cylinder 32 is preferably constructed such that the major axis of the ellipse is contained within the plane containing the core O of the cylinder 32 and the Z-axis intersecting the core O.

[0052] For example, Figure 3A As shown, the cylindrical body 32 constructed in this way can be manufactured from a cylindrical material 32α whose inner circumferential surface is circular in a cross-section perpendicular to the shaft core O. That is, by horizontally cutting off the upper and lower portions of the cylindrical material 32α, a cylindrical body 32α can be formed with the shaft core O of the cylindrical material 32α inclined at a predetermined angle θ2 relative to the vertical direction (Z-axis direction). Figure 1A The cylindrical body 32 is shown. In this embodiment, the inner circumferential surface 33 of the cylindrical body 32 is formed continuously along the axis O in a cross section that is inclined at an angle θ1 relative to the axis O.

[0053] like Figure 2B As shown, in this embodiment, in the ellipses appearing on each horizontal cross-section of the inner circumferential surface 33 of the cylinder 32, the ratio of the major axis L3 to the minor axis L2 (L3 / L2) is preferably 1.01 or more and 3.00 or less, more preferably 1.04 or more and 2.00 or less, and particularly preferably in the range of 1.04 or more and 1.30 or less. With this configuration, the flow rate of the coolant (e.g., cooling water) can be easily changed, and a coolant layer of uniform thickness can be formed. For example, although the flow rate, fluid pressure, and thickness of the coolant layer also vary, setting L3 / L2 to 1.04 to 3.00 can make the velocity ratio (maximum velocity / minimum velocity) of the coolant flow rate about 1.07 to 1.33.

[0054] like Figure 1A As shown, a discharge section 34 is provided below along the axis O of the cylinder 32. The discharge section 34 can discharge metal powder contained in the coolant layer 50 along with the coolant to the outside. The inner diameter of the inner circumferential surface of the discharge section 34 can be smaller than the inner diameter of the inner circumferential surface 33 of the cylinder 32. Preferably, the inner diameter continuously decreases from the inner circumferential surface 33 of the cylinder 32 toward the inner circumferential surface of the discharge section 34. Furthermore, the horizontal cross-section of the inner circumferential surface of the discharge section 34 is not necessarily elliptical and can also be circular. Preferably, the horizontal cross-section of the inner circumferential surface 33 of the cylinder 32 is an ellipse of the same size from the upper part of the cylinder 32 along the axis O toward the discharge section 34.

[0055] Along the shaft O of the cylinder 32, a coolant outlet 36 is provided at the upper part. For example... Figure 1BAs shown, the coolant outlet 36 has a frame 38 and an outer forming member (outer frame forming member) 45. The outer forming member 45 may be integrally formed with the cylinder 32, or it may be separately formed from the cylinder 32 and installed on the cylinder 32.

[0056] An outer forming member 45 forms an outer space 44 on the upper part of the cylinder 32 and on the outer side of the inner circumferential surface 33. Additionally, an auxiliary cylinder 40 is mounted on the upper inner circumferential surface of the cylinder 32. The auxiliary cylinder 40 may also be the upper opening edge of the cylinder 32 itself, but in the illustrated example, it is formed separately from the cylinder 32 and mounted on the upper inner circumferential surface of the cylinder 32. The inner circumferential surface of the auxiliary cylinder is preferably flush with the inner circumferential surface 33 of the cylinder 32, but it may differ.

[0057] The frame 38 can also be integrally formed with the cylinder 32, but it is preferred to form it separately from the cylinder 32, having an inner frame piece 39a disposed on the inner side of the inner circumferential surface of the cylinder 32 and a frame support piece 39b intersecting the inner frame piece 39a at a predetermined angle. For example... Figure 1C As shown, the frame support plate 39b is a plate in the shape of a generally elliptical ring, and the inner frame plate 39a has a generally elliptical cylindrical shape with a central axis Oa inclined at an angle θ1 (relative to the right axis of the ellipse) from the central opening edge of the generally elliptical shape of the frame support plate 39b.

[0058] Figure 1C The inner frame piece 39a shown has a shaft core Oa and Figure 1A The cylinder 32 shown has the same shaft core O, and the horizontal cross section of the outer peripheral surface of the inner frame piece 39a has a ratio of Figure 1A The horizontal cross-section of the inner circumferential surface 33 of the shown cylinder 32 (or the inner circumferential surface of the auxiliary cylinder 40) has a similar elliptical shape with a smaller inner diameter. That is, the outer circumferential surface of the inner frame piece 39a has a smaller diameter and is parallel to the inner circumferential surface 33 of the cylinder 32 (or the inner circumferential surface of the auxiliary cylinder 40).

[0059] like Figure 1A As shown, the outer diameter portion of the frame support piece 39b is mounted on the upper end of the outer forming member 45 or the upper end of the cylinder 32. Alternatively, the outer diameter portion of the frame support piece 39b may be integrally formed with the upper end of the outer forming member 45 or the upper end of the cylinder 32. The inner diameter portion of the frame support piece 39b and the inner frame piece 39a, together with the inner circumferential surface of the cylinder 32, the inner circumferential surface of the auxiliary cylinder 40, and / or the inner circumferential surface of the outer forming member 45, define an inner space 46 on the upper part of the cylinder 32 and inside the inner circumferential surface 33.

[0060] In addition, such as Figure 1BAs shown, the outer side forming member 45 divides the outer side space 44 on the outer side of the upper portion of the cylinder 32 and the inner peripheral surface 33 together with the cylinder auxiliary sheet 40. The inner side space 46 is located on the inner side of the radial direction of the outer side space, communicates with the outer side space 44 through the passage portion 42. The upper end of the auxiliary cylinder 40 or the cylinder 32 is located between the outer side space 44 and the inner side space, so that the passage portion 42 is formed at the uppermost portion of the outer side space 44 or a position close thereto along the axis core O of the cylinder 32.

[0061] In the present embodiment, the outer side space 44 is formed as a substantially elliptical ring shape continuously in the horizontal direction on the outer side of the inner peripheral surface 33 of the cylinder 32. The inner side space 46 is formed as a substantially elliptical ring shape continuously in the horizontal direction along the inner peripheral surface 33 on the inner side of the inner peripheral surface 33 of the cylinder 32. The passage portion 42 is also formed as a substantially elliptical ring shape continuously in the horizontal direction. The up and down width Wl of the passage portion 42 along the axis core O is narrower than the up and down width W2 of the axis core direction of the outer side space 44. Wl / W2 is preferably 1 / 2 or less.

[0062] A cooling liquid supply line 37 for introducing cooling liquid is attached on the radial direction outer side of the outer side forming member 45. The connection port of the supply line 37 to the outer side space 44 is preferably located lower than the passage portion 42 along the axis core O.

[0063] In the outer side space 44, it is preferable that the cooling liquid flowing from the supply line 37 forms a flow from the lower side of the outer side space toward the upper side and forms a flow from the passage portion 42 into the inner side space 46. In addition, the lower end of the inner frame sheet 39a for forming the inner side space 46 is preferably located on the lower side than the passage portion 42 along the axis core O, and a cooling liquid discharge port 52 is formed between the lower end of the inner frame sheet 39a and the inner peripheral surface 33 of the cylinder 32 (including the inner peripheral surface of the cylinder auxiliary sheet 40). As shown in Figure 1C The lower end of the inner frame sheet 39a divides a substantially elliptical opening in the horizontal plane.

[0064] The inner diameter of the cooling liquid discharge port 52 coincides with the outer diameter of the inner frame sheet 39a, and the outer diameter of the cooling liquid discharge port 52 coincides with the inner peripheral surface of the cylinder 32 (the inner diameter of the cylinder auxiliary sheet 40). The cooling liquid discharge port 52 is preferably formed as a substantially elliptical ring shape continuously in the circumferential direction in the horizontal cross section.

[0065] The cooling liquid discharge port 52 communicates with the inner side space 46, and the cooling liquid of the inner side space 46 is ejected toward the inner peripheral surface 33 of the cylinder 32 from the cooling liquid discharge port 52 in an elliptical spiral shape. In the present embodiment, the radial width of the cooling liquid discharge port 52 is not particularly limited, but is determined in relation to the thickness of the cooling liquid layer 50 of the cooling liquid flowing along the inner peripheral surface of the cylinder 32.

[0066] As shown in Figure 1AAs shown, the axial length LI of the inner frame piece 39a is determined to cover Figure 1B The length in the direction of the axis core O of the passage portion 42 to the extent of the width Wl is determined to form the cooling liquid discharge port 52 on the upstream side of the position where the molten metal discharged from the molten metal supply portion 20 contacts the cooling layer 50. In addition, as shown in FIG. 2, the axial length LI of the inner frame piece 39a is determined to expose the cooling liquid layer 50 to the inner side by the axial length L0 of the inner peripheral surface 33 of the cylinder body 32. Figure 1A

[0067] The length L0 of the cooling liquid layer 50 exposed to the inner side along the axis core O is preferably 5 to 500 times the axial length LI of the inner frame piece 39a. In addition, the inner diameter (minor axis of the ellipse) of the inner peripheral surface 33 of the cylinder body 32 is not particularly limited, but is preferably 50 to 500 mm.

[0068] In the present embodiment, the cooling liquid supply line 37 can also be connected in the tangential direction of the cooling liquid discharge portion 36. The cooling liquid can enter the inside of the outer side space 44 from the cooling liquid supply line 37 in a manner of rotating in an elliptical spiral around the axis core O. The cooling liquid that has entered the inside of the outer side space 44 in a scroll shape passes through the passage portion 42 to enter the inside of the inner side space 46 in a scroll shape.

[0069] In the present embodiment, in the cooling liquid discharge portion 36, the cooling liquid is temporarily stored in the outer side space 44 disposed on the outside of the cylinder body 32. In addition, the outer side space 44 is formed in a substantially elliptical shape. By thus configuring, the cooling liquid is guided to the inner side space 46 while rotating in an elliptical shape in the outer side space 44.

[0070] In addition, in the present embodiment, because the lower end of the passage portion 42 is formed above the lower end of the outer side space 44, the cooling liquid is temporarily lifted upward while rotating in an elliptical spiral in the outer side space 44, and then enters the inner side space 46 through the passage portion 42. By passing through the passage portion 42, the cooling liquid that has entered the inner side space 46 on the inside of the upper portion of the cylinder body 32 has its flow rate accelerated, collides with the inner frame piece 39a of the inner side space 46, and changes the direction of flow.

[0071] ​The cooling liquid that has passed through the passage portion 42 provided in the upper portion of the cylinder 32 and entered the inside of the inner space 46 in an elliptical scroll shape is changed to flow downward along the inner frame piece 39a (along the axis core O). In addition, the frame support piece 39b blocks the flow of the cooling liquid upward. The cooling liquid forms an elliptical ring-like flow along the inner circumferential surface 33 around the axis core O in the inner space 46. Also, with respect to the cooling liquid, the force of gravity acts downward along the inner circumferential surface 33 (along the axis core O), and by the synergistic effect of the force of gravity, the cooling liquid is discharged in a manner that it flows in a substantially elliptical spiral track along the inner circumferential surface 33 from the cooling liquid discharge outlet 52. The cooling liquid that is discharged from the cooling liquid discharge outlet 52 forms a cooling liquid layer 50 in which the cooling liquid flows in an elliptical spiral shape along the inner circumferential surface 33 at a substantially constant thickness.

[0072] As shown in Figure 1A , in the present embodiment, because the cooling liquid is supplied from the cooling liquid lead-out portion 36 to the inner side of the upper portion of the cylinder 32, which is the inner circumferential surface 33 formed in an elliptical shape, the cooling liquid can form a cooling liquid layer 50 that flows in a substantially elliptical spiral shape along the inner circumferential surface 33 of the cylinder 32. By causing the molten droplets of the molten metal 21, that is, the dropped molten metal 21a to be incident on the inner surface of this cooling liquid layer 50 by spattering, it is possible to more rapidly cool the dropped molten metal 21a. As shown in Figure 2A and Figure 2B , the flow of the cooling liquid in an elliptical spiral shape is faster on the short diameter side of the ellipse and slower on the long diameter side, and the dropped molten metal 21a that is spattered to the cooling liquid layer 50 flows in the cooling liquid layer 50 while changing the flow rate along with the cooling liquid.

[0073] By causing the dropped molten metal 21a to flow in the cooling liquid layer 50 while changing the flow rate along with the cooling liquid, it is believed that the film of vapor that is generated around the dropped molten metal 21a after it has contacted the cooling liquid easily peels off from the dropped molten metal 21a, and the dropped molten metal 21a easily cools rapidly in the cooling liquid layer 50. By thus rapidly cooling the dropped molten metal 21a, it is possible to produce a metal powder that is good in amorphousness or magnetic characteristics even if the particle diameter is small.

[0074] As shown in Figure 1A , in the present embodiment, the cooling liquid discharge outlets 52 are formed continuously in a substantially elliptical shape along the circumferential direction of the cylinder 32, but a reinforcing member or the like can be provided at the cooling liquid discharge outlets 52 and formed discontinuously along the circumferential direction of the cylinder 32. By forming the cooling liquid discharge outlets 52 along the circumferential direction of the cylinder 32, it is possible to form a cooling liquid layer 50 of the cooling liquid that flows in an elliptical spiral shape along the inner circumferential surface 33 of the cylinder 32.

[0075] As shown in Figure 1AAs shown, in the present embodiment, the cooling liquid leading-out portion 36 is capable of forming a cooling liquid discharge port 52 in a substantially elliptical shape between the inner frame piece 39a and the inner peripheral surface 33 of the cylinder body 32. As a result, the cooling liquid flowing in an elliptical spiral shape can be discharged from the cooling liquid discharge port 52 along the inner peripheral surface 33 of the cylinder body 32.

[0076] As shown, in the present embodiment, the inner peripheral surface 33 forms an ellipse whose center deviates in a manner that the inclination angle θ2 with respect to the vertical line (Z axis) becomes larger as it goes toward the lower portion of the cylinder body 32. As shown, the cooling liquid layer 50 formed along the inner peripheral surface 33 flows in an elliptical spiral orbit while being inclined with respect to the vertical direction (the direction of gravity). Figure 1A Figure 2A As shown, the cooling liquid of the cooling liquid layer 50 formed along the inner peripheral surface 33 flows while drawing an elliptical spiral orbit and while being inclined with respect to the vertical direction (the direction of gravity).

[0077] Therefore, under the condition that the length along the Z axis is the same, the distance of the elliptical spiral in which the cooling liquid flows can be lengthened. In addition, by ejecting the molten metal toward one end of the long axis of the inner peripheral surface 33 of the cylinder body 32 in the direction of gravity, the droplet of the molten metal 21a easily enters the inner peripheral surface 33 (the cooling liquid layer 50) of the cylinder body 32 from the upper end opening of the cylinder body 32, and the droplet of the molten metal can be cooled smoothly.

[0078] Further, in the above-described embodiment, the horizontal cross section of the inner peripheral surface 33 of the cylinder body 32 is an ellipse whose size is the same from the upper portion of the cylinder body 32 toward the discharge portion 34 along the axis core O, but the horizontal cross section of the inner peripheral surface 33 of the cylinder body 32 can be at least substantially elliptical in shape at the upper portion of the cylinder body 32, and can change in the middle toward the discharge portion 34 along the axis core O, for example, can gradually change from substantially elliptical to substantially circular (or other).

[0079] In addition, the horizontal cross section of the inner peripheral surface 33 of the cylinder body 32 is preferably such that the ratio (L3 / L2) of the major axis L3 and the minor axis L2 of the ellipse is constant from the upper portion of the cylinder body 32 toward the discharge portion 34 along the axis core O, but can change. For example, the ratio (L3 / L2) can be made smaller or larger from the upper portion of the cylinder body 32 toward the discharge portion 34 along the axis core O, or can change so that they alternate.

[0080] In addition, the horizontal cross section of the inner peripheral surface 33 of the cylinder body 32 can be such that the direction of the major axis of the ellipse gradually changes from the upper portion of the cylinder body 32 toward the discharge portion 34 along the axis core O. For example, it can change so that the direction of the major axis of the ellipse coincides with the inclination direction of the axis core O of the cylinder body 32 at the upper portion of the cylinder body 32, and the direction of the major axis of the ellipse is substantially perpendicular to the inclination direction of the axis core O of the cylinder body 32 at the lower portion of the cylinder body 32.

[0081] ​In the present embodiment, the angle θ2 of the shaft core O of the cylinder 32 to the vertical direction is not particularly limited, but is preferably 5 to 45 degrees. By setting to such an angle range, the dripped molten metal 21a from the molten metal discharge port 23 is easily ejected toward the cooling liquid layer 50 formed on the inner peripheral surface 33 of the cylinder 32.

[0082] In the present embodiment, the cooling liquid discharge portion 36 is formed in a manner that the frame support piece 39b becomes horizontal, but if the cooling liquid layer 50 is formed in an elliptical spiral shape, it is not limited thereto.

[0083] Second Embodiment

[0084] As Figure 4 shown, the metal powder manufacturing apparatus 110 and the metal powder manufacturing method of another embodiment of the present application are the same as the first embodiment except for the following, and common members are labeled with common member names and symbols, and the description of a part of the common portion is omitted.

[0085] The ring 35 is fixed to the inner peripheral surface 33 of the cylinder 32 constituting the cooling portion 30 on the downstream side. The ring 35 functions as a weir (or a baffle) on the downstream side of the cooling liquid layer 50 on the inner peripheral surface 33 of the cylinder 32. The cooling liquid layer 50 becomes a predetermined thickness by being blocked from flowing in the shaft core O direction by the ring 35, and flows to the lower portion of the cylinder 32 over the ring 35. By providing the ring 35 on the downstream side of the cooling liquid layer 50, the ring 35 controls the flow of the cooling liquid in the direction along the shaft core O of the cylinder 32, and easily controls the thickness of the cooling liquid layer 50 to a constant thickness.

[0086] In the present embodiment, the ring 35 is installed inclined at an angle θ1 with respect to the shaft core O of the cylinder 32, and is formed in an elliptical ring shape along the inner peripheral surface 33 of the cylinder 32. It is preferable that the radial thickness of the ring 35 corresponds to the radial thickness of the cooling layer 50, and is substantially the same as the radial width of the discharge port 52.

[0087] Furthermore, the present application is not limited to the above-described embodiments, and various changes can be made within the scope of the present application.

[0088] For example, unlike the above-described embodiments, instead of Figure 3A the cylindrical material 32α whose inner peripheral surface 33 perpendicular to the shaft core O is circular as shown, an elliptical cylindrical material whose cross section of the inner peripheral surface perpendicular to the shaft core O is substantially elliptical shape can be used as the cylinder 32 as shown. Figure 3B

[0089] In Figure 3A the embodiment shown, the cylindrical material 32α is cut, and the inner peripheral surface 33 inclined with respect to the shaft core O is formed in an elliptical shape, but as shown, Figure 3B ​As shown, a cylindrical member whose cross section of the inner peripheral surface 33 perpendicular to the axis core O is elliptical can also be used in advance. Further, as shown in Figure 2A As shown in the above-described first embodiment, the elliptical spiral flow whose center of the ellipse around the Z axis is changed along the axis core O of the cylindrical body is formed, but in the present embodiment, the elliptical spiral flow whose center of the ellipse along the inner peripheral surface 33 of the cylindrical body is moved along the axis core O is realized.

[0090] Example

[0091] Hereinafter, the present application will be described based on more detailed examples, but the present application is not limited to these examples.

[0092] Example

[0093] Using Figure 1A The metal powder manufacturing apparatus 10 whose angle θ2 is 25 degrees and the ratio (L3 / L2) of the major axis L3 to the minor axis L2 of the ellipse of the circumferential surface is 1.10 was used to manufacture metal powders composed of Fe-Si-B (Experiment No. 7), Fe-Si-Nb-B-Cu (Experiment No. 8), Fe-Si-B-P-Cu (Experiment No. 10), Fe-Nb-B (Experiment No. 12), Fe-Zr-B (Experiment No. 13), and Fe-Co-Si-B-P-Cu (Experiment No. 14).

[0094] In addition, the metal powder manufacturing apparatus 10 whose angle θ2 is 15 degrees and L3 / L2 is 1.04 was used to manufacture Fe-Co-Si-B-P-Cu (Experiment No. 9). Further, the metal powder manufacturing apparatus 10 whose angle θ2 is 40 degrees and L3 / L2 is 1.30 was used to manufacture Fe-Co-Si-B-P-Cu (Experiment No. 11).

[0095] In each experiment, the melting temperature was 1500°C, the injection gas pressure was 5 MPa, the kind of gas used was constant as argon, and the spiral flow condition was pump pressure of 7.5 kPa. In the example, it was possible to manufacture metal powders that were small and had less variation in average particle diameter of 24.9 to 26.2 μm for each composition. The average particle diameter was measured using a dry-type particle size distribution measuring device (HELLOS). In addition, the crystalline analysis of the metal powders produced in Experiment Nos. 7 to 14 was evaluated by powder X-ray diffraction method. In the example, it was possible to confirm that amorphous metal powders were manufactured. As for the magnetic properties of the metal powders, the coercive force (Oe) was measured by using an Hc meter. The results are shown in Table 1. In addition, it was observed that the variation in the axis core O direction was small at a thickness of 30 mm of the cooling liquid layer 50.

[0096] In addition, the speed ratio (maximum speed / minimum speed) of the flow rate of the cooling liquid was about 1.07 when L3 / L2 was 1.04, about 1.16 when L3 / L2 was 1.10, and about 1.20 when L3 / L2 was 1.30.

[0097] Reference Example

[0098] As shown in Figure 5A and Figure 5B , the metal powder was produced in the same manner as in the examples except that the metal powder production device in which the inner peripheral surface 33 of the cylinder 32 was circular (L3 / L2 = 1.00) in the cross section perpendicular to the axis core O, the lower end of the inner frame piece 39a of the cooling liquid leading-out portion divided the opening of the circle in the cross section perpendicular to the axis core O, and the cooling liquid discharge port 52 was circular, and the same evaluation was performed (Experiment Nos. 1 to 6). The results are shown in Table 1.

[0099] Comparing the examples and the reference example in Table 1, regarding the magnetic properties of the metal powder, in the same composition, the coercive force was smaller in the examples than in the reference example, and it was confirmed that the magnetic properties were excellent in the examples. It is considered that this result that the magnetic properties were excellent although the pump pressure was the same as that of the reference example and the flow rate of the cooling water was the same is due to the following phenomenon.

[0100] In the metal powder production device of the reference example, as shown in Figure 5A and Figure 5B , the cooling liquid flowing on the inner peripheral surface formed a circular spiral-shaped cooling liquid layer. Therefore, it is considered that the flow rate of the cooling liquid on the inner peripheral surface was substantially constant (the speed ratio of the flow rate of the cooling liquid was about 1.00). In contrast, in the examples, as shown in Figure 2A and Figure 2B , the cooling water formed a substantially elliptical spiral-shaped cooling liquid layer 50. In the elliptical spiral-shaped cooling liquid layer 50, the flow rate was slower on the long diameter side and faster on the short diameter side, and the flow rate was variable. Therefore, the molten metal droplets of the molten metal ejected to the cooling liquid layer 50 flowed while changing the flow rate together with the cooling liquid layer. It is considered that the reason for this is that the film of vapor around the molten droplet, which is considered to be generated after the molten droplet contacts the cooling liquid, easily peels off from the molten droplet due to the change in the flow rate, and the rapid cooling effect of the molten droplet in the cooling liquid layer is improved.

[0101] Table 1

[0102]

[0103] Explanation of Reference Numerals

[0104] 10, 110... Metal powder production device

[0105] 20... Molten metal supply portion

[0106] 21 …… molten metal

[0107] 22 …… vessel

[0108] 23 …… molten metal discharge port

[0109] 24 …… heating coil

[0110] 26 …… gas nozzle

[0111] 27 …… gas injection port

[0112] 30, 130 …… cooling portion

[0113] 32 …… cylindrical body

[0114] 32a …… cylindrical material

[0115] 33 …… inner peripheral surface

[0116] 34 …… discharge portion

[0117] 35 …… ring

[0118] 36 …… coolant lead-out portion

[0119] 37 …… supply line

[0120] 38 …… frame

[0121] 39a …… inner frame piece

[0122] 39b …… frame support piece

[0123] 40 …… cylinder auxiliary piece

[0124] 42 …… passage portion

[0125] 44 …… outer side space

[0126] 45 …… outer side forming member

[0127] 46 …… inner side space

[0128] 50 …… coolant layer

[0129] 52 …… coolant discharge port

Claims

1. A metal powder manufacturing apparatus characterized by comprising: a molten metal supply section that discharges a molten metal; a cylinder that has a cooling liquid layer that cools the molten metal formed on an inner circumferential surface; and a cooling liquid guide section that supplies the cooling liquid to an inner side of an upper portion of the cylinder.

2. The metal powder manufacturing apparatus according to claim 1, characterized in that the cooling liquid guide section has a cooling liquid discharge port that discharges the cooling liquid supplied from an outer side of the cylinder in a manner that the cooling liquid flows in a spiral track along the inner circumferential surface from the upper portion of the cylinder.

3. The metal powder manufacturing apparatus according to claim 2, characterized in that the cooling liquid discharge port is formed in a substantially elliptical shape over a circumferential direction of the cylinder.

4. The metal powder manufacturing apparatus according to any one of claims 1 to 3, characterized in that the frame section has a frame support section that is a substantially elliptical ring shape that intersects the inner frame section at a prescribed angle, and in that a lower end of the inner frame section divides an opening of the substantially elliptical shape in a horizontal plane.

5. The metal powder manufacturing apparatus according to claim 4, characterized in that the frame section is disposed on an inner side of the cylinder, and forms an inner side space in which the cooling liquid enters from an outer side of the cylinder, and in that the inner side space is formed in a substantially elliptical shape along the inner circumferential surface.

6. The metal powder manufacturing apparatus according to any one of claims 1 to 3, characterized in that the cooling liquid guide section has an outer side formation member that forms an outer side space that temporarily stores the cooling liquid, and in that the outer side formation member is disposed on an outer side of the cylinder, and in that the outer side space is formed in a substantially elliptical shape.

7. The metal powder manufacturing apparatus according to any one of claims 1 to 3, characterized in that a center of the elliptical shape formed by the inner circumferential surface deviates in a manner that tilts with respect to a vertical line as it goes toward a lower portion of the cylinder.

8. The metal powder manufacturing apparatus according to any one of claims 1 to 3, characterized in that a ratio of a minor axis to a major axis in the elliptical shape formed by the inner circumferential surface is 1.04 or more and 3.00 or less.

9. A metal powder manufacturing method characterized by comprising: a process of forming a cooling liquid layer that has a flow rate that changes along an inner circumferential surface of a cylinder, by causing cooling liquid that flows in from an outer side of the cylinder to collide with an inner frame section that is a substantially elliptical shape that is disposed on an inner side of the inner circumferential surface of the cylinder and that tilts in a manner that follows an axis of the cylinder, and that changes a direction of the cooling liquid to form a flow of the cooling liquid that is an elliptical ring shape along the inner circumferential surface, and discharging the cooling liquid from a cooling liquid guide section in a manner that the cooling liquid flows in a substantially elliptical spiral track along the inner circumferential surface. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ a step of discharging molten metal toward the cooling liquid layer from a molten metal supply portion; and a step of flowing the molten metal together with the cooling liquid while changing a flow rate.

10. The method of manufacturing a metal powder according to claim 9, wherein the cooling liquid is caused to flow along the inner circumferential surface in a substantially elliptical spiral shape to form the cooling liquid layer.

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