JP2006241562A - Continuous atomization device for molten metal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous atomization device for molten metal where molten metal made to flow down from a melting furnace is not swung or does not flow backward, and powdering can be securely performed at the stable flow of the molten metal. <P>SOLUTION: The continuous atomization device 1 for molten metal comprises: a semilevitation melting furnace 1 where the inside is sealable, and also, has an electromagnetic tapping nozzle 10 on the furnace bottom; a plurality of atomization nozzles 30 arranged at intervals each other to molten metal M vertically flowing down from a tapping port 14 in the tapping nozzle 10, and further spraying inert gas (atomization medium) G to a powdering position F obliquely downward and also in the same position; a chamber 40 where the atomization nozzles 30 are arranged on the upper part at the inside; and a pressure tuning tube 44 of allowing the melting furnace 2 to communicate with the chamber 40. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molten metal continuous spraying method for stably producing a metal powder by spraying a molten metal flowing down with a small diameter, and a continuous spraying apparatus used therefor.

  In order to prevent metal powder from being blown up near the pulverization point when atomizing gas is blown into the molten metal flowing down from the bottom of the tundish, it is shaped like a ring (ring) of the atomizing nozzle and slits against the molten metal. There has been proposed a method for producing metal powder by gas atomization that lowers the atomizing gas spray pressure at the beginning of atomization in which the inert gas of the atomizing medium is ejected from an injection port exhibiting (see, for example, Patent Document 1). The metal powder obtained by this is accommodated in the chamber located under the nozzle.

Japanese Patent Laid-Open No. 3-140402 (pages 1 to 3, FIG. 1)

  However, in the metal powder manufacturing method, when atomizing gas of the spray medium is sprayed in a conical shape obliquely downward from the ring-shaped injection port toward the pulverization point, the powder is discharged from the injection port surrounded by the atomizing gas. The conical space up to the turning point is in a reduced pressure state. For this reason, even if the atomizing gas spraying pressure is lowered at the beginning of atomization, a part of the metal powder formed at the pulverization point may collide with new atomizing gas and blow up into the decompression space. is there. As a result, an inadvertent flow is generated in the decompression space, so that it interferes with the molten metal flowing vertically through the central portion of the decompression space, and the flow of the molten metal occurs.

Moreover, the inside of the tundish or the melting furnace that can discharge the bottom of the furnace is at normal pressure, and the conical space from the injection port surrounded by the atomizing gas to the pulverization point (spraying focal point) is in a depressurized state. There are three types of pressure differences in the chamber containing the metal powder, ie, a pressurized state. For this reason, when an abrupt pressure change occurs for some reason, there is a possibility of causing a backflow or a turbulent flow in the flowing metal melt.
For these reasons, in the method for producing the metal powder, it may be difficult to continuously perform stable atomization (spraying).

  The present invention solves the problems described in the background art, and the molten metal flowing down from the melting furnace does not shake or backflow, and can be reliably pulverized with a stable molten metal flow. It is an object to provide a continuous spray device.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-mentioned problem, the present invention includes a plurality of spray nozzles spaced from each other on the chamber side in order to spray the spray medium onto the molten metal flowing down from the bottom of the sealable melting furnace, The idea is to create the same pressure in the melting furnace and in the chamber.
That is, the molten metal continuous spraying apparatus according to the present invention (Claim 1) includes a melting furnace in which the inside of the furnace can be hermetically sealed and having a tapping nozzle at the bottom of the furnace, and a molten metal that flows vertically from a tapping outlet of the tapping nozzle. On the other hand, a plurality of spray nozzles that are spaced apart from each other and spray the spray medium obliquely downward and at substantially the same position, a chamber in which the plurality of spray nozzles are disposed in the upper part on the inside, and in the chamber A pressure tuning tube communicating with the inside of the melting furnace.

  According to this, since the plurality of spray nozzles are arranged at intervals, the inner space of the plurality of spray media sprayed therefrom and the inside of the chamber can be made to have the same pressure. For this reason, the above-described metal powder blowing and molten metal shake do not occur. Furthermore, since the pressure in the melting furnace and the chamber are equalized via the pressure tuning tube, the molten metal flows backward or turbulently due to pressure increase in the chamber and the inner space surrounded by the plurality of spraying media. Can be prevented. At the same time, since it is possible to prevent an increase in the hot water discharge speed that occurs when the spray medium is sprayed from the ring-shaped and slit-shaped injection port, it is possible to maintain a constant hot water discharge speed. Therefore, stable continuous spraying can be performed in which the molten metal flowing down the central portion of the inner space formed by the plurality of spray media is reliably made into a metal powder having a fine particle size.

  The spray medium includes water (atomized water) in addition to an inert gas (atomized gas) such as argon, nitrogen, and helium. In addition to the semi-levitation melting furnace described later, the melting furnace includes various melting furnaces that can be hermetically sealed and can be discharged from the bottom of the furnace. For example, a ladle or a tundish is also included if an electromagnetic hot water nozzle can be attached.

Further, according to the present invention, the hot water discharge nozzle of the melting furnace is an electromagnetic hot water nozzle comprising a main body made of metal and having a substantially conical shape that can be cooled with water, and a high frequency induction coil wound around the outer periphery of the main body. The continuous metal spraying device (Claim 2) is also included.
According to this, since the molten metal flows down continuously from the melting furnace through the electromagnetic hot water nozzle, the molten metal can be discharged continuously with a relatively small diameter and cleanliness. Moreover, as described above, since the pressure in the inner space surrounded by a plurality of spraying media from the spray port to the pulverization point is not reduced, it occurs when spraying from a conventional ring-shaped and slit-shaped spray port. It is possible to reliably prevent an increase in the temperature of the hot water, and it is possible to maintain a constant hot water speed. Therefore, since the molten metal can flow continuously and stably (free fall), continuous spraying can be performed more reliably and stably.

Further, in the present invention, the plurality of spray nozzles are arranged in a continuous metal melt spraying apparatus (three or more spaced apart from each other with respect to the trajectory of the molten metal flowing downward and symmetrically arranged). Claim 3) is also included. According to this, since the three or more spray nozzles are arranged at intervals from each other, the inner space and the outer space (in the chamber) of the plurality of spray media sprayed from these nozzles are surely the same. Can be compressed. As a result, it is possible to reliably eliminate the fluctuation, backflow, or turbulent flow of the molten metal.
The plurality of spray nozzles are equally spaced along a circular circumferential direction located on the same plane, for example, 3, 4, 6, 8, 12, or 16 diagonally downward and Arranged in a centripetal manner.

In addition, according to the present invention, the plurality of spray nozzles have their proximal ends communicating with an annular medium supply chamber built in an annular medium supply body disposed on the upper side in the chamber, and A continuous molten metal spraying device (Claim 4) penetrating the upper part of the chamber is also included.
According to this, the spray medium supplied to the annular medium supply chamber built in the medium supply body can be ejected from the bottom surface of the medium supply body into a plurality of nozzles in a conical shape as a whole. At the same time, an interval can be reliably formed between the plurality of spray media flowing down near the bottom surface of the nozzle body.

In other words, the present invention also includes a continuous molten metal spraying device in which the melting furnace is a semi-levitation melting furnace (cold crucible melting apparatus) having a water-cooled copper crucible inside the furnace. Can be.
In this case, for example, a raw material of Ti alloy is charged into a copper crucible, and the high frequency induction coil located on the outer periphery of the crucible is energized, so that the raw material does not contact the inner wall surface of the crucible and becomes hemispherical. It is possible to dissolve in a rising molten Ti alloy. In addition, since the molten metal flows through the electromagnetic hot water nozzle, the metal powder having a desired particle size and alloy composition, since it has a small diameter and flows down to the center of the space surrounded by the plurality of spray nozzles. Can be obtained reliably.

In the following, the best mode for carrying out the present invention will be described.
FIG. 1 is a vertical sectional view showing a molten metal continuous spraying apparatus (hereinafter simply referred to as a continuous spraying apparatus) 1 according to the present invention.
As shown in FIG. 1, the continuous spraying apparatus 1 includes a semi-levitation melting furnace 2 in which the inside of the furnace can be sealed, an electromagnetic hot water nozzle (hot water nozzle) 10 attached to the bottom of the furnace, and a position below the nozzle 10. Chamber 40, a plurality of spray nozzles 30 which are attached to the upper part of the chamber 40 and are obliquely downward and attached in a substantially conical shape, and a pressure tuning pipe 44 which is piped between the melting furnace 2 and the chamber 40. And.

  As shown in FIG. 1, the semi-levitation (semi-magnetic levitation) melting furnace 2 includes a furnace body (crucible) 3 made of copper and having a hollow cylindrical portion 4 and an outer peripheral surface of the furnace body 3. And a high-frequency induction coil 8 spirally wound along. The furnace body 3 is divided into a plurality of segments by a plurality of vertical insulating slits (not shown) arranged in the circumferential direction, and the water supply holes 6, the hollow portions 4, and the drain holes 7 at the upper end are formed. The cooling water w is circulated and supplied in the normal route. Further, the upper furnace body 5 including the top plate 5a is detachably attached to the upper side of the furnace body 3, and an upper end 47 of a pressure tuning tube 44 communicating with the chamber 40 is opened on the side wall thereof.

  As shown in FIG. 1, a horizontal portion 12 of an electromagnetic hot water nozzle (a hot water nozzle) 10 is attached to the furnace bottom of the furnace body 3 of the semi-levitation melting furnace 2. The electromagnetic hot water nozzle 10 has a main body 11 having an annular horizontal portion 12, a cone portion 13 connected to the lower side thereof, and a hot water outlet 14 connected to the lower side thereof, and a spiral shape along the outer peripheral surface of the main body 11. And a high-frequency induction coil 16 wound in a conical shape. The cooling water is circulated and supplied to the hollow portion 15 built in the main body 11 as described above.

In the electromagnetic hot water nozzle 10, an induction current flows through the metal main body 11 and is heated by a magnetic field formed by energizing the induction coil 16. At this time, the main body 11 dissolves the substantially inverted conical solidified shell solidified after the previous dissolution inside the cone portion 13 and the outlet 14 at the previous melting due to the heat generation, as shown in FIG. A small diameter molten metal M is caused to flow vertically from the hot water outlet 14. That is, by continuously energizing and stopping the induction coil 16, it is possible to easily control the continuous discharge of the molten metal M and the stop of the discharge.
As shown in FIG. 1, an atomizing gas (spraying medium) supply device 20 is disposed below the electromagnetic hot water nozzle 10 via a heat resistant pipe 18 made of a known refractory material. The atomizing gas supply device 20 includes an annular medium supply body 21 attached to the upper side of the top plate 41 of the chamber 40 positioned below, an annular medium supply chamber 22 built in the medium supply body 22, and the heat-resistant pipe. 18 is provided with a central vertical hole 24 communicating with 18 and a pair of symmetrical supply pipes 26 and 28.

As shown in the horizontal sectional views of FIGS. 1 and 3, the opening position of the pair of supply pipes 26 and 28 to the medium supply chamber 22 is about 20 degrees with respect to the radial line passing through the center of the medium supply body 21. The air supply pipes 26 and 28 are substantially tangential so that the axes of the supply pipes 26 and 28 are parallel to each other.
By piping the air supply pipes 26 and 28 as described above, an inert gas (atomizing gas as a spraying medium) G can be introduced into the medium supply chamber 22 from each with a uniform pressure. An inert gas G such as argon can be injected from the nozzle hole 34 of the nozzle 32 at a uniform flow rate and pressure.

  As shown in FIGS. 1, 2, and 3, the plurality of spray nozzles 30 include eight elongated nozzles (unit nozzles) 32. Each nozzle 32 has a nozzle hole 34 having a small diameter at an intermediate position along the axial center thereof. The eight nozzles 32 are spaced from each other through the seals of the base ends 36 on the bottom surface of the medium supply body 21 so that the nozzle holes 34 communicate with the inner peripheral end of the bottom surface of the medium supply chamber 22. It is mounted diagonally downward and symmetrically. The inclination angle of each nozzle 32 with respect to the vertical line is appropriately selected within a range of 2 to 20 degrees.

  Further, as shown in FIG. 1, the inside of the chamber 40 and the inside of the melting furnace 2 are communicated with each other by a pressure tuning tube 44 having a lower end 46 opened on a side wall 42 of the chamber 40. For this reason, since the pressure in the chamber 40 does not increase, it is difficult for backflow or turbulent flow of the molten metal M flowing down. In addition, the discharge speed of the molten metal M flowing down from the melting furnace 2 in combination with the conical inner space surrounded by the eight inert gases G indicated by the dashed-dotted arrows in FIG. Is also constant. An on-off valve 48 is attached in the middle of the pressure tuning tube 44.

The effect | action of the above continuous spraying apparatuses 1 is demonstrated below.
First, after charging, for example, a Ti alloy as a raw material into the furnace 3 of the melting furnace 2, the upper furnace body 5 is attached and the inside of the furnace is sealed. Next, when a required high-frequency current is passed through the high-frequency induction coil 8, a magnetic field formed around the coil 8 passes through the furnace body 3, penetrates the inner Ti alloy, and is induced on the surface of the skin. The Ti alloy is heated and melted by Joule heat generated by electric current. In the molten metal M made of the Ti alloy, an induced current flows induced by the coil 8 and, as shown in FIG. 1, due to a repulsive force (Lorentz repulsive force) generated between these currents, the molten metal M is Then, the inside of the furnace body 3 is separated from the side wall and is in a semi-levitation state rising in a hemispherical shape. In addition, since the molten metal M is cooled in contact with the lower part of the side wall of the furnace body 3 and the horizontal part 12 of the electromagnetic nozzle 10, the molten metal M is illustrated on the lower part of the inner side surface of the side wall and the horizontal part 12 of the tapping nozzle 10. A solidified shell is formed.

Next, the induction coil 16 of the electromagnetic hot water nozzle 10 is energized, and an induced current is passed through the metal main body 11 by the magnetic field formed, which heats the induction coil 16. At this time, the main body 11 melts the substantially inverted conical solidified shell solidified inside the cone portion 13 and the outlet 14 at the time of the previous melting due to the heat generation, and as shown in FIG. Together with the molten metal M to be melted, the molten metal M is made to flow vertically from the outlet 14 as a thin metal melt M.
As shown in FIG. 1, the molten metal M flows down toward the powdering point F in the chamber 40 after flowing down the central portion of the heat-resistant pipe 18 and the vertical hole 24 of the medium supply body 21.

As shown in FIGS. 1 and 4, eight inert gases (atomizing medium) sprayed from the nozzle port 38 of the nozzle hole 34 in each nozzle 32 through the medium supply chamber 22 with respect to the molten metal M. G is sprayed in a conical shape toward the powdering point F. As a result, the molten metal M collides with the inert gas G and is pulverized into the metal powder P. The metal powder P is appropriately taken out after being deposited on the bottom plate of the chamber 40.
At the time of the spraying, the eight inert gases G flow obliquely downward toward the same pulverization point F at intervals near each nozzle 32. For this reason, the conical inner space surrounded by the eight inert gases G has the same pressure as the inside of the chamber 40.

The molten metal M that flows down due to the same pressure does not cause fluctuations, and thus collides with eight inert gases G at the same pulverization point F accurately. As a result, the metal powder P having a desired particle size can be continuously produced.
At the same time, since the inside of the chamber 40 and the inside of the melting furnace 2 communicate with each other via the pressure tuning pipe 44, they are also made the same pressure. For this reason, the molten metal M flowing down from the melting furnace 2 has a constant hot-water speed and does not generate backflow or turbulent flow. As a result, since the molten metal M can be allowed to flow naturally (free fall) from the electromagnetic hot water nozzle 10 to a predetermined position, it becomes possible to perform continuous and stable spraying with the eight inert gases G.

Note that the pressure tuning pipe 44 externally transfers the metal powder P obtained from the electromagnetic hot water nozzle 10 in a state where the molten metal M does not flow, for example, when the raw material is charged into the furnace of the melting furnace 2 or from the chamber 40. When discharging, the on-off valve 48 is closed.
As described above, according to the present continuous spraying apparatus 1, the metal powder P is not blown up, and the molten metal M flowing down, the backflow, and the turbulent flow do not occur. It is possible to perform continuous and stable gas spraying with the metal melt M flowing down to a desired particle size and alloy composition.

The present invention is not limited to the embodiment described above.
5 and 6 includes a plurality of spray nozzles 30a and 30b in which six or twelve nozzles 32 are attached to the bottom surface of the same medium supply body 21 at equal intervals and symmetrically. Have That is, at least three spray nozzles 32 are arranged at equal intervals and symmetrically to form a plurality of spray nozzles in the present invention.
Moreover, instead of the inert gas, water (atomized water) may be applied to the spray medium.
Further, instead of the melting furnace 2, another type of melting furnace in which the inside of the furnace can be sealed and a hot water discharge nozzle at the bottom of the furnace can be used, or a tundish.
In addition, instead of the electromagnetic hot water nozzle 10, a hot water nozzle having a sliding gate in which a refractory valve slides in the horizontal direction may be used.

The vertical sectional view which shows the continuous spraying apparatus of this invention. The bottom view which shows the several spray nozzle vicinity in the said continuous spray apparatus. The horizontal sectional view of the medium supply body in the above-mentioned continuous spraying device. The perspective view which shows the outline of an effect | action of the said continuous spraying apparatus. The bottom view which shows the some spray nozzle vicinity of a different form. Furthermore, the bottom view which shows the some spray nozzle vicinity of a different form.

Explanation of symbols

1 ………………………… Continuous spraying device 2 ………………………… Semi levitation melting furnace (melting furnace)
10 ……………………… Electromagnetic hot water nozzle (hot water nozzle)
11 …………………… Main body 14 ………………………… Outlet 16 ………………………… High-frequency induction coil 21 ………………………… Medium supply body 22 ……………………… Medium supply chamber 30, 30a, 30b… Multiple spray nozzles 32 ……………………… Spray nozzle 40 ……………………… Chamber 44 ………… …………… Pressure tuning tube M ………………………… Molten metal G ………………………… Inert gas (spray medium)

Claims (4)

A melting furnace in which the inside of the furnace can be sealed and has a hot water nozzle at the bottom of the furnace;
A plurality of spray nozzles that are arranged at intervals from each other and are sprayed obliquely downward and substantially at the same position with respect to the molten metal that flows vertically from the hot water outlet of the hot water nozzle;
A chamber in which the plurality of spray nozzles are arranged in an upper part inside;
A pressure tuning tube communicating between the chamber and the furnace of the melting furnace,
A continuous spray device for molten metal characterized by the above. The melting nozzle of the melting furnace is an electromagnetic hot water nozzle comprising a metal-made main body that is substantially conical and water-cooled, and a high-frequency induction coil wound around the outer periphery of the main body.
The continuous spraying apparatus for molten metal according to claim 1. The plurality of spray nozzles are arranged obliquely downward and symmetrically with respect to a trajectory in which the molten metal flows down, with three or more spaced apart from each other.
The continuous spraying apparatus for molten metal according to claim 1 or 2, characterized in that: The plurality of spray nozzles communicate with an annular medium supply chamber incorporated in an annular medium supply body disposed on the upper side of the chamber, and pass through the upper part of the chamber.
The continuous spraying apparatus for molten metal according to any one of claims 1 to 3.

Images