JP4134310B2 - Electromagnetic stirring device and electromagnetic stirring method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic stirring device and an electromagnetic stirring method capable of stirring the melt strongly and uniformly without contact and suppressing the deformation of the surface of the melt, and in particular, (1) alloy production. (Especially when alloy components with greatly different densities are mixed uniformly), (2) Metal-base particle-dispersed composite material production, (3) Super clean metal material production by thorough separation of inclusions in metal, (4) High refining The present invention relates to an electromagnetic stirring device and an electromagnetic stirring method that can be used in a metal manufacturing field such as high-purity metal material manufacturing by function.
[0002]
[Prior art]
The conventional apparatus for performing non-contact stirring of a metal melt includes (1) a fixed magnetic field induction electric furnace, (2) an electromagnetic stirrer using a rotating (circumferential) direction moving magnetic field, and (3) an electromagnetic using an axial moving magnetic field. It can be classified into four types: agitator and (4) agitator by rotating a permanent magnet.
[0003]
The purpose of (1) is to heat and dissolve the metal and stir, but there is a problem that two swirl flows are formed above and below the metal melt, and stirring cannot be performed over the entire melt. (2) is used for electromagnetic stirring of the unsolidified part of the slab in continuous casting, but when applied to the stirring of the metal melt in the container, the liquid level is greatly deformed by rotation, so that large electric power cannot be input. There is a drawback. Moreover, since the melt behaves close to a rigid body rotation only by the rotational motion, the melt is not sufficiently mixed. Although these problems can be avoided by installing baffle plates, the baffle plate is a new problem.
[0004]
(3) uses the ASEA-SKF furnace stirring method, but there is a problem that the slag as a refining material is biased and the molten metal surface is exposed. Moreover, since the scale is large, there is a problem that it is inferior in versatility. (4) is a stirring method recently proposed by Prof. Vives of France. A rotating cylinder with a permanent magnet arranged in a spiral shape is rotated around the container to generate driving force simultaneously in the rotational direction and the axial direction of the melt. By doing so, it is aimed to obtain large agitation while suppressing deformation of the liquid surface. However, as a result of the experiment according to the present invention, it has been found that there is a large resistance to the axial movement as compared with the rotational movement of the melt, and a sufficient effect cannot be obtained.
[0005]
[Problems to be solved by the invention]
An object of this invention is to provide the novel electromagnetic stirring apparatus and electromagnetic stirring method which can stir a melt uniformly and strongly over the whole in non-contact.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides:
A predetermined container;
A rotating magnetic field generating coil provided along the outer peripheral surface of the container;
In the outer peripheral surface of the container, comprising an axial moving magnetic field generating coil provided along the axial direction of the container ,
The rotating magnetic field generating coil and the axial magnetic field generating coil constitute a magnetic circuit different from each other, and respectively generate rotational motion and axial motion with respect to the fluid in the container. About.
[0007]
The present invention also provides:
A step of containing a predetermined melt in a predetermined container;
Creating a rotational motion in the melt by a rotating magnetic field generating coil provided along the outer peripheral surface of the container;
Producing an axial motion in the melt by an axially moving magnetic field generating coil provided along the axial direction of the container on the outer peripheral surface of the container ,
The rotational stirring by the rotating magnetic field generating coil and the axial movement by the axial moving magnetic field generating coil are caused by different magnetic circuits, and the method relates to an electromagnetic stirring method.
[0008]
According to the magnetic stirrer of the present invention, the rotating magnetic field generating coil is provided along the outer peripheral surface of the container that should contain the melt, and the shaft provided along the axial direction of the container on the outer peripheral surface of the container. A direction moving magnetic field generating coil is provided. Therefore, the melt contained in the container is caused to generate a rotational motion by the rotating magnetic field generating coil based on the electromagnetic stirring method of the present invention, and an axial motion by the axial moving magnetic field generating coil. Is born. As a result, a strong flow velocity motion in which the rotational motion and the axial motion are superimposed is generated in the melt, and the melt is strongly and uniformly stirred.
[0009]
Further, in the state where the flow velocity motion in which the rotational motion and the axial motion are superimposed as described above, a downward flow is generated with respect to the melt in the outer peripheral portion of the container, and the melt is generated in the center portion of the container. On the other hand, an upward flow is generated. As a result, the liquid surface of the melt can be kept flat, and a large current is applied to the rotating magnetic field generating coil and the axial direction moving magnetic field generating coil, thereby causing a large flow velocity motion to the melt. Can give birth. In addition, the melt can be prevented from overflowing from the container .
[0010]
In a preferred embodiment of the present invention, the rotating magnetic field generating coil and the axial direction moving magnetic field generating coil are controlled independently. Thereby, rotational motion and axial motion can be independently controlled and applied to the melt, and the degree of stirring of the melt can be freely set. Therefore, the stirring mode can be freely changed from linear stirring to rotary stirring in the axial direction of the container. Furthermore, according to such unique control, it is possible to easily generate a downward flow and an upward flow in the outer peripheral portion and the central portion of the melt in the container, and to make the liquid level of the melt flat. Can be maintained.
[0011]
The rotating magnetic field generating coil and the axially moving magnetic field generating coil are preferably provided on the outer peripheral surface of the container so as to cover the melt contained in the container. Thereby, stronger flow velocity motion can be produced over the whole melt, and the whole melt can be stirred more uniformly and strongly.
[0012]
The present invention can be used mainly in the metal manufacturing field as described above. In particular, since a large velocity gradient can be formed in the melt, it is possible to promote the aggregation and enlargement of inclusion particles in the melt.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail according to embodiments of the invention. FIG. 1 is a schematic view showing an example of an electromagnetic stirring device of the present invention. An electromagnetic stirring device shown in FIG. 1 includes a cylindrical container 1, a rotating magnetic field generating coil (hereinafter sometimes abbreviated as “R coil”) 2 provided along the outer peripheral surface of the container 1, and a container 1. Is provided with an axial direction moving magnetic field generating coil (hereinafter sometimes abbreviated as “L coil”) 3 provided along the axial direction. The R coil 2 causes a rotational movement with respect to the melt contained in the container 1, and the L coil 3 causes an axial movement with respect to the melt.
[0014]
For the container 1, for example, a metal container made of plastic having an inner diameter of 55 mm and a height of 150 mm is used. For the R coil 2, for example, a bipolar rectangular coil piece is used. For the L coil 3, for example, a circular coil piece is used.
[0015]
These coils are installed in an annular container filled with a cooling oil (not shown) to prevent overheating due to energization. The R coil 2 is energized via a voltage regulator from a 50 Hz three-phase AC power source, and the L coil 3 is energized with a three-phase AC of an arbitrary frequency via a frequency variable inverter.
[0016]
The number of R coils 2 and L coils 3 is not particularly limited, and is arbitrarily set according to the type and amount of the melt to be stirred in the container 1 and the mode and strength of stirring. In FIG. 1, the number of R coils 2 and L coils 3 is set to six. The container 1 contains a melt 4, and the R coil 2 and the L coil 3 are provided on the outer peripheral surface of the container 1 so as to cover the melt 4.
[0017]
FIG. 2 shows, as a graph (a), the results obtained by filling the container 1 shown in FIG. 1 with molten Ga up to a height of 100 mm and measuring the height distribution in the radial direction of the molten Ga liquid surface by the deep needle method. FIG. 2 also shows that only the R coil is energized to cause only the rotational movement of the molten Ga, and only the L coil is energized to cause only the axial movement of the molten Ga. The height distribution in the radial direction in the case of the case is shown as graphs (b) and (c), respectively.
[0018]
2, the numerical value “0” indicates the radial center in the container 1. In addition, preliminary experiments confirmed that the frequency of the axially moving magnetic field is optimally 1300 Hz under this experimental condition.
[0019]
In the case where the rotational motion and the axial motion are generated with respect to the molten Ga, the liquid surface is almost flat as is apparent from the graph (a) of FIG. 2, but only the rotational motion is performed with respect to the molten Ga. When produced, the liquid level was found to be greatly recessed at the center of the container 1 as is apparent from the graph (C). In addition, when only the axial motion is generated with respect to the molten Ga, as is apparent from the graph (b), it can be seen that the liquid level rises in the central portion.
[0020]
3-5 is a figure which shows typically the phenomenon mentioned above. FIG. 3 shows a case where a rotational motion and an axial motion are generated with respect to the melt according to the present invention. In this case, as is apparent from FIG. 3, a downward flow is generated with respect to the melt at the outer peripheral portion of the container, and this downward flow is reversed at the bottom of the container to become an upward flow. Push up the liquid level. As a result, the liquid surface of the melt is substantially uniform over the radial direction of the container.
[0021]
FIG. 4 shows a case where only a rotational motion is generated with respect to the melt. In this case, since the vortex resulting from the rotational motion is generated, the liquid level of the melt is recessed at the center of the container as shown in FIG. FIG. 5 shows a case where only the axial motion is generated with respect to the melt. In this case, since an upward flow is generated in the melt at the center of the container, the liquid level rises at the center of the container.
[0022]
FIG. 6 is a graph showing a result of monitoring the state of the rotational motion when the electromagnetic stirring device shown in FIG. 1 is used to cause rotational motion and axial motion of the melt. In FIG. 6, similarly to the case where the graph shown in FIG. 2 is obtained, the molten Ga is filled up to a height of 100 mm, and a flat blade rotor blade is disposed in the molten Ga to generate the rotational motion. The rotational state of the molten Ga was monitored from the relationship between the applied current value and the rotational speed of the rotary blade based on the rotational motion of the molten Ga.
[0023]
As is apparent from the graph of the black plot in FIG. 6, when only the rotational motion is generated with respect to the molten Ga, the current value applied to the R coil 2 and the rotational speed of the rotary blade are almost directly proportional. . On the other hand, when a predetermined current is supplied to the L coil 3 to cause an axial movement with respect to the molten Ga, the axial movement relative to the R coil 2 in both the upward and downward axial movements. For the same applied current value, the rotational speed of the rotor blade, that is, the rotational motion of the molten Ga slightly decreased, but a result almost proportional to the current value was obtained.
[0024]
That is, according to the result shown in FIG. 6, even when an axial motion is applied to the rotational motion, the melt can be superposed evenly by superimposing both of them without impairing the rotational motion. I understand.
[0025]
As described above, the present invention has been described according to the embodiment of the invention. However, the content of the present invention is not limited to the above, and various modifications and changes can be made without departing from the scope of the present invention. is there.
[0026]
【The invention's effect】
As described above, according to the present invention, the rotating magnetic field generating coil is provided along the outer peripheral surface of the container that should contain the melt, and the outer peripheral surface of the container is provided along the axial direction of the container. An axial moving magnetic field generating coil is provided, and the melt is caused to rotate by the rotating magnetic field generating coil, and the axial moving magnetic field generating coil is caused to cause axial movement. As a result, a strong flow velocity motion in which the rotational motion and the axial motion are superimposed is generated in the melt, and the melt is strongly and uniformly stirred.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an example of an electromagnetic stirring device of the present invention.
FIG. 2 is a graph showing the result of measuring the height distribution in the radial direction of the molten Ga liquid surface by the deep needle method.
FIG. 3 is a diagram conceptually showing a change in a melt liquid level due to rotational movement and axial movement.
FIG. 4 is a diagram conceptually showing a change in a melt liquid level only by a rotational motion.
FIG. 5 is a diagram conceptually showing a change in a melt liquid level due to an axial movement.
FIG. 6 is a graph showing a result of monitoring the state of the rotational motion in the case where the rotational motion and the axial motion are caused to the melt.
[Explanation of symbols]
1 Container 2 Rotating Magnetic Field Generating Coil 3 Axial Moving Magnetic Field Generating Coil 4 Melt

Claims (10)

A predetermined container;
A rotating magnetic field generating coil provided along the outer peripheral surface of the container;
In the outer peripheral surface of the container, comprising an axial moving magnetic field generating coil provided along the axial direction of the container ,
The rotating magnetic field generating coil and the axial magnetic field generating coil constitute a magnetic circuit different from each other, and respectively generate rotational motion and axial motion with respect to the melt in the container. apparatus.   The electromagnetic stirrer according to claim 1, wherein the rotating magnetic field generating coil and the axially moving magnetic field generating coil are controlled independently of each other.   The electromagnetic stirrer according to claim 1 or 2, wherein the rotating magnetic field generating coil and the axially moving magnetic field generating coil are provided so as to cover the melt contained in the container.   The electromagnetic stirrer according to any one of claims 1 to 3, wherein the rotating magnetic field generating coil includes a plurality of coils provided along the outer peripheral surface of the container.   5. The coil according to claim 1, wherein the axially moving magnetic field generating coil is composed of a plurality of coils that circulate around an outer peripheral surface of the container and that are provided along the axial direction of the container. The electromagnetic stirring apparatus as described in one. A step of containing a predetermined melt in a predetermined container;
Producing a rotational motion in the melt by a rotating magnetic field generating coil provided along the outer peripheral surface of the container;
Producing an axial motion in the melt by an axially moving magnetic field generating coil provided along the axial direction of the container on the outer peripheral surface of the container ,
The electromagnetic stirring method, wherein the rotational movement by the rotating magnetic field generating coil and the axial movement by the axial moving magnetic field generating coil are generated through different magnetic circuits .   The electromagnetic stirring method according to claim 6, wherein the rotating magnetic field generating coil and the axially moving magnetic field generating coil are controlled independently.   The electromagnetic stirring method according to claim 6 or 7, wherein the rotating magnetic field generating coil includes a plurality of coils provided along the outer peripheral surface of the container.   The axial movement magnetic field generating coil is composed of a plurality of coils provided around the outer peripheral surface of the container and along the axial direction of the container. The electromagnetic stirring method as described in one.   Due to the superposition of the rotational motion by the rotating magnetic field generating coil and the axial motion by the axial moving magnetic field generating coil, a downward flow is generated with respect to the melt at the outer peripheral portion of the container, and the center of the container The electromagnetic stirring method according to any one of claims 6 to 9, wherein the liquid level of the melt is kept flat by generating an upward flow in the part.

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