JP2813151B2 - Apparatus and method for electromagnetically confining molten metal with the aid of conduction current - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to an apparatus and method for electromagnetically confining molten metal, and more particularly, to the use of two horizontally spaced members on which molten metal is located. An apparatus and method for preventing molten metal from leaking from the open end of a vertically extending gap.

[0002]

BACKGROUND OF THE INVENTION An example of an environment in which the present invention works is a system for continuously casting molten metal directly into a plate, for example a plate made of steel. Such systems typically have a pair of horizontally spaced, counter-rotating rolls that define a vertically extending gap between them for receiving molten metal. doing. The gap defined by the rolls tapers downwardly between the rolls. These rolls are cooled and then cool the molten metal as it moves down the gap, with the solid metal plate emerging between the rolls.

The gap has an open end at each of the adjacent ends of the roll.

[0004] The molten metal is not confined by rolls at each open end of the gap. Dams must be provided to prevent metal from flowing out through the open ends of the gap. Mechanical dams or seals are used for this purpose, but these are disclosed in Pareg US Pat.
There are disadvantages described in US Pat. No. 6,374 and Lari et al., US Pat. No. 4,974,661, the disclosure of which is incorporated herein by reference.

[0005] To overcome the inherent disadvantages of using mechanical dams or seals, it has a magnetic core surrounded by electrically conductive coils and is spaced apart adjacent the open end of the gap. Efforts have been made to confine the molten metal at the open end of the gap by employing an electromagnet having a pair of magnets. The magnet is energized by flow through a time-varying (e.g., alternating or fluctuating direct current) coil, the magnet extending temporally across the open end of the gap between the poles of the magnet. Produces a changing magnetic field. The magnetic field can be either horizontal or vertical depending on the arrangement of the poles of the magnet. Examples of magnets that produce a horizontal magnetic field are described in the aforementioned Pareg U.S. Pat. No. 4,936,374 and in Preag U.S. Pat. No. 5,251,68.
It is described in No. 5. Examples of magnets that produce a perpendicular magnetic field are described in the aforementioned Lari et al., U.S. Pat. No. 4,974,661. The disclosures of all of these patents are incorporated herein by reference.

[0006] The time-varying magnetic field induces eddy currents in the molten metal adjacent the open end of the gap. The induced eddy currents create their own time-varying magnetic field, which supplies the open end of the gap with a magnetic flux density that is in addition to the magnetic flux density provided by the magnetic field generated from the electromagnet. The resulting repulsion is directed at the molten metal at the open end of the gap. The repulsion is expressed as follows.

[0007]

(Equation 1)

Where f is the repulsive force at the open end of the gap,
J is the peak induced current density in the molten metal, and B is (1)
The peak magnetic flux density due to the magnetic field from the electromagnet and (2) the magnetic field from the induced eddy current.

Another approach to magnetically confine the molten metal to the open end of the gap between the pair of rolls is to place a coil near the open end of the gap to allow time-varying current to flow. . This creates a magnetic field in the coil that induces eddy currents in the molten metal near the open end of the gap, creating repulsions similar to those described above for systems using magnetic poles near the gap. Examples of magnetically confined dam type coils are U.S. Pat.No. 5,197,534 to Gerber et al.
No. 5,279,350 to Rber, the disclosures of which are incorporated herein by reference.

Further, with respect to repulsion, the integral gives the average repulsive magnetic pressure P, which, for a coil of the type of example of a magnetic confinement dam, is expressed as:

[0011]

(Equation 2)

Here, k is a coupling factor between the coil and the molten metal, μ is the magnetic permeability of air (and the molten metal), and B is the peak magnetic flux density (described above).

[0013] The binding agent is typically less than one. If the molten metal is steel, and if the frequency of the time-varying current is 3000 Hertz, the coupling factor (k) will be somewhere between about 0.18 and 0.90, and the gap opening Depends on the geometry of the pool of molten metal at the edges.
The binding factor decreases with increasing skin depth (ie, penetration) of the induced eddy currents in the molten metal. Since the skin depth increases with decreasing frequency, a decrease in frequency results in a decrease in the coupling factor (k), which leads to a decrease in the repulsive pressure (p).

In order to include the molten steel, the repulsion pressure must be at least equal to the pressure pushing the molten metal outward through the open end of the gap between the rolls. The repulsion pressure (p) can be increased by increasing the peak magnetic flux density (B) created by the dam, but increasing the magnetic flux density also increases the power loss (wasted as heat) at the dam. The average power loss per unit area at a dam is given by:

[0015]

(Equation 3)

Where (δ) is the depth of the skin of copper, the depth of the skin, and this substance is the material of the confinement coil;
(Μ) is the magnetic transmittance of copper.

From the above equation, it can be seen that the power loss at the dam can be reduced by increasing the skin depth (δ), which increases by reducing the frequency of the time-varying current. However, as described above, a decrease in frequency reduces the coupling factor (k), which results in a decrease in the repulsive pressure (P).

[0018]

[Problems to be solved by the invention]

It is desirable to (1) provide a sufficiently high repulsion pressure to provide confinement of the molten metal, while (2) reduce the power loss at the dam. In other words, a relatively high ratio of containment pressure to power loss at the dam must be provided. This ratio (P / PL) is expressed as follows.

[0019]

(Equation 4)

Where (δ) is the skin depth in copper (coil material) and (μ) is air (and copper and molten steel)
, (K) is a coupling factor between the coil and the molten metal. For this discussion, it can be assumed that the magnetic permeability (μ) of air, copper and molten steel are the same.

[0021]

According to the present invention, power loss at a dam is reduced without substantially reducing the repulsion pressure. This is achieved by using conduction current in the molten metal. Such an arrangement has several advantages (discussed below) over an arrangement employing solely the induced eddy currents in the molten metal to generate the confined magnetic field.

The confinement coils employed in all of the embodiments of the present invention are positioned vertically facing the pool of molten metal at the open end of the gap between the rolls of the continuous plate casting machine. A first confinement coil portion. First
Is electrically connected to the bottom of a second vertically arranged confinement coil.

An upper electrode extends to the top of the pool of molten metal near the open end of the gap. On the other hand, the lower electrode or brush is (a) in contact with the solidified steel plate located immediately below the portion between the rolls, or (b) in contact with the two rolls at that position, or (c) As shown in (b) and (b), it is in contact with both the plate and the roll.

In all embodiments, a time-varying current is introduced into the first confinement coil section. In one embodiment, all of the current from the power supply (ie, the secondary coil of the transformer) first flows down through the first coil section and is then split into the following two currents: (a) one current is directed upward through a second confinement coil section;
(b) The other current is directed to the lower electrode or brush just below the sandwich of the roll and then upwardly through the pool of molten metal as conduction current to reach the upper electrode.

In another embodiment, the current from the power supply is initially provided as a separate, separate current. That is,
(a) one current is directed to the first and second confinement coil sections as described above, (b) the other current is first directed to the lower electrode or brush, and then the conduction current as described above. Flows upward through the molten metal.

In all embodiments, pools of molten metal have induced eddy currents as well as conduction currents. These eddy currents are induced in the pool of molten metal by the magnetic field generated by the confinement coil. The magnetic flux density (B), which provides the repulsive pressure to confine the molten metal in the pool, combines the three components. That is, (1) the magnetic flux density due to the magnetic field generated by the current flowing through the confinement coil; (2) the magnetic flux density due to the magnetic field generated by the eddy current induced in the pool of molten metal; and (3) the conduction through the pool of molten metal. This is the magnetic flux density due to the magnetic field generated by the current. The second component, (2), is a factor that is substantially smaller for the overall magnetic flux density than an arrangement where the current in the molten metal pool is solely the induced current.

As mentioned above, as the frequency of the time-varying current decreases, the power loss in the coil of the confinement dam decreases, but the skin depth (δ) of the induced eddy current in the molten metal pool. Also increase. Increasing the skin depth (depth of eddy current penetration) reduces the coupling factor (k) between the confinement coil and the molten metal, which in turn reduces the repulsive pressure.

However, as for the conduction current in the molten metal pool, the penetration depth (current distribution) of the current does not depend much on the frequency, but rather on the arrangement of the electrodes.

(If the time-varying conduction current is a fluctuating DC, the frequency reduction does not substantially affect the current distribution; if the time-varying conduction current is an AC, the frequency reduction will be The effect on the current distribution is substantially less than in the configuration without the conduction current.) Therefore, a decrease in the frequency of the time-varying conduction current does not cause a significant change in the current distribution. Thus, there is no significant decrease in binding factor (k), which decreases with increasing skin depth.

As a result, the reduction in frequency that reduces the power loss in the confinement coil does not result in a reduction in the coupling factor associated with the conduction current, and also results in a large decrease in magnetic flux density due to the magnetic field generated by the conduction current. Absent. The negative impact on the repulsive pressure resulting from such a frequency reduction will be substantially less than the negative consequences resulting from the situation where the current in the pool of molten metal is the induced eddy current alone.

The decrease in the frequency of the time-varying current is
Not only does it reduce the power loss of the confinement coil,
It also reduces power loss in the molten metal.

The time-varying current produces a time-varying magnetic field having a corresponding frequency with a cycle of increasing and decreasing magnetic flux density. The ability of the magnetic field to confine the molten metal can be adversely affected if the frequency of the time-varying current is reduced too much.

This frequency cannot be reduced below the lower limit, which means that the period of time between the peak magnetic flux densities for successive cycles of the time-varying magnetic field is reduced through the open end of the gap between the rolls. This frequency is too long to suppress the outflow of the molten metal.

For a given input current to the confinement system, the magnetic flux density generated by the arrangement according to the present invention employing the conduction current of the pool of molten metal is such that the current in the pool of molten metal is derived from the induced eddy current only. Larger than the magnetic flux density generated by such an arrangement.

Other features and advantages are inherent in the apparatus and method claimed, disclosed, or will be apparent to those skilled in the art from the following detailed description, taken in conjunction with the accompanying drawings.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1-3, generally indicated at 30 is an electromagnetic confinement device which comprises two horizontally spaced members 3.
A device for preventing molten metal from leaking from an open end 36 of a vertically extending gap 35 between the two members 31 and 32, and a pool 38 of molten metal is provided between the two members 31 and 32.
Is located. The horizontally spaced members are:
It has a pair of casting rolls that rotate in opposite directions to continuously cast a plate. The casting rolls 31, 32 have a nip 39 at the bottom of a vertically extending gap 35 therebetween. A pair of rolls rotating in opposite directions are formed from a molten pool 38 by a continuous plate 3 extending downward from a nip 39.
7 has means for solidifying the metal. Roll 31,
32 is cooled by conventional means not shown here. Pool 38 is typically of molten steel.

Without the confinement device, molten metal in gap 35 would leak through the open end 36 of gap 35.
Although only one open end 36 and one electromagnetic confinement device are shown in the accompanying drawings, it should be understood that there is a device 30 at each of the two open ends 36 of the gap 35.

Referring to FIGS. 5 to 7 and 10, the electromagnetic confinement device 30 has an electrically conductive confinement coil 40 near the open end 36 of the gap 35. Coil 40
Generates a first horizontal magnetic field extending toward the molten metal pool 38 through the open end 36 of the gap 35.

The coil 40 is vertically connected to a first confinement coil portion 41 which is vertically arranged facing the open end 36 of the gap 35 and is electrically connected to the first coil portion 41 at 43. And a second confinement coil section 42. Second
Are arranged at an interval facing the back of the first coil section 41.

Referring to FIGS. 3 to 6 and 10, the electromagnetic confinement device 30 includes (a) a plate 37 and (b) a casting roll near the opening end 36 of the gap 35 and below the nip 39. It has brushes 46 and 47 that are electrically connected to at least one of 31 and 32. The apparatus 30 has an electrode 48 at a position on the nip 39 near the open end 36 of the gap 35 for electrically connecting to the molten metal pool 38.

Referring to FIGS. 5, 6 and 10, the device 30
In connection therewith, there is provided a transformer 50 having a main coil 51 for receiving an input current and at least one auxiliary coil 52 shown in FIG. In the embodiment of FIG. 5, the auxiliary coil has a separate pair of coil portions 52a and 52b. In the embodiment of FIG. 10, the auxiliary coil is in the form of a center tap coil shown at 73.

Referring again to the embodiment of FIG. 5, the first confinement coil section 41 has an upper end 44 and a lower end 45. The vertically arranged confinement coil section 42 has an upper end 54 and a lower end 55. As aforementioned,
The transformer 50 has a pair of separate and separate coil portions 52a and 52b. Each auxiliary coil section has a pair of coil ends facing each other. Line 56 connects one end 70 of auxiliary coil section 52b to first confinement coil section 4
1 is electrically connected to the upper end 44. Return line 5
Reference numeral 7 electrically connects the other end 71 of the auxiliary coil portion 52b to the upper end portion 54 of the second confinement coil portion 42. The line 58 is connected to one end 6 of the auxiliary coil portion 52a.
0 to the brush 4 via the branch lines 58a and 58b, respectively.
6, 47 (FIG. 3). The return line 59 is connected to the other end 61 of the auxiliary coil portion 52a of the transformer.
Is electrically connected to the electrode 48.

The lines 56 and 57 are connected to the first coil unit 4
1 is directed in a first vertical direction (below in FIG. 5) from the transformer 50 via the first coil section 42 and then in the first vertical direction via the second coil section 42. It has a first conducting means which is directed in the second vertical direction, that is, upwards via the second coil part 42. More specifically, the current from the auxiliary coil portion 52b of the transformer flows through line 56, then flows down through the first confinement coil portion 41, and then through the coil portions 41 and 42. Bottom 45,
55 electrical connection 43 and then the second confinement coil 4
2 and then return to the auxiliary coil section 52b via the line 57. The time-varying current flowing through the confinement coil portions 41 and 42 generates a first horizontal magnetic field near the opening end 36 of the gap 35.

Electrically conductive line 58, branch line 58
a, 58b, brushes 46, 47, electrode 48 and electrically conductive return line 59 have a second conductive means;
This causes the time-varying current from the auxiliary coil portion 52a of the transformer to be directed vertically through the molten metal pool 38 as a conduction current near the open end 36 of the vertically extending gap 35. The flow of conduction current through the pool 38 is in a direction opposite to the flow of current through the first confinement coil portion 41 (ie, upward through the molten metal pool 38). This flow of the conduction current generates a second horizontal magnetic field near the opening end 36 of the gap 35.

First and second confinement coil portions 41, 4
The directions of the current flow through 2 are indicated by 62 and 63, respectively, and the direction of the conduction current through the molten metal pool 38 is indicated by 64 (FIGS. 5 and 7). The first and second horizontal magnetic fields are shown at 65 and 66 in FIG.
These two magnetic fields flow in the same direction and are increasing with each other.

The confinement coil 40 and the first and second conductive means (as described above), in the presence of the molten metal pool 38,
A device cooperates to provide a magnetic repulsion pressure that pushes the molten metal back inward from the open end 36 of the gap 35.

Referring to the embodiment of FIG. 6, the auxiliary coil of the transformer has a single coil 52. In this embodiment, the line 56 electrically connects one end 90 of the auxiliary coil 52 to the upper end 44 of the first confinement coil section 41. The return line 57 electrically connects the upper end 54 of the second confinement coil section 42 to the other end 91 of the auxiliary transformer coil 52. The lower end portion 45 of the first confinement coil portion 41 is connected to the brushes 46 and 47 via the electric connection portion 43 and a pair of connection lines 68 (only one of which is shown in FIG. 6). Return line 5
9 connects the electrode 48 to the terminal end 91 of the auxiliary transformer coil 52. As described above, the end 91 is connected to the return line 57.
, And then to the upper end 42 of the second confinement coil section 42.

In the embodiment of FIG. 6, the time-varying current is
The current flows from the auxiliary coil 52 of the transformer through the line 56 and then through the first confinement coil section 42 to the electrical connection 43 where the current is split. Some of the current flows upward through the second confinement coil section 42 and then back through line 57 to the auxiliary coil of the transformer. The other part of the current flows through the connecting lines 68 to the brushes 46, 47, then through the molten metal pool 38 to the electrode 48, and from there back to the transformer auxiliary coil 52 via the return line 59. .

In the embodiment shown in FIG.
The direction of current flow through the molten metal pool 38 and the direction of current flow through the
2, 63 and 64, respectively, and these directions are:
This is the same as the direction of current flow in the embodiment of FIG.

The time-varying current flowing through the coil 40 is
A first horizontal magnetic field having a direction indicated by 65 in FIG. 7 is generated, and the time-varying conduction current flowing through the molten metal pool 38 generates a second horizontal magnetic field having a direction indicated by 66 in FIG. These are in the same direction as the magnetic field generated by the embodiment of FIG. Similarly, the second horizontal magnetic field having the direction indicated by 66 in FIG. 7 increases the first horizontal magnetic field having the direction indicated by 65 in FIG. 7 and applies a magnetic repulsive pressure to the open end 36 of the gap 35. Increase.

In all embodiments of the present invention, the conduction current flowing vertically through the molten metal pool 38 has a direction 64 that is opposite to the direction 62 of the current flowing vertically through the first confinement coil 41. Always flows to As a result of this relationship, the direction 66 of the horizontal magnetic field generated by the conduction current flowing through the molten metal pool 38 is always the same as the direction 65 of the horizontal magnetic field generated by the coil 40. First and second
When the horizontal magnetic fields flow in the same horizontal direction (65, 66 in FIG. 7), they reinforce each other.

In addition to the conduction current flowing through the molten metal pool 38, there is also an eddy current in the molten metal pool 38 induced by the first horizontal magnetic field and flowing in the same direction 64 as the conduction current. The horizontal magnetic field generated by the eddy current flows in the same direction 66 as the horizontal magnetic field generated by the conduction current flowing through the molten metal pool, and the conduction current and the confinement coil 4
A horizontal magnetic field generated by a time-varying current flowing through zero.

FIGS. 5 and 6 show an embodiment in which the time-varying current is an alternating current. The time-varying current may be a fluctuating direct current. An embodiment employing a fluctuating direct current is shown in FIG. The embodiment of FIG.
And there are some differences. The same part is not repeated. The differences are described below.

The transformer 50 shown in FIG.
9 has an auxiliary coil 72 having a center tap 73 connected thereto. Each end of the auxiliary coil 72 is connected to a rectifier 74, 75, respectively, and then electrically connected to a line 56 towards the upper end 44 of the first confinement coil section 41, respectively. The fluctuating DC from the rectifiers 74 and 75 flows downward through the first confinement coil unit 41. When the current leaves the first confinement coil section 41,
At its lower end 45 the current is split into two parts, the first part of the split current being directed via the electrical connection 43 to the second confinement coil part 42 and flowing upwardly there and split. A second portion of the electrical current is directed through the electrical connection 68 and the brushes 46, 47 to the molten metal pool 38, where the second portion flows upward. The return line 57 connects a current flowing from the upper end 45 of the second confinement coil section 42 to the center tap 73 of the auxiliary transformer coil 72,
Return line 59 connects the current flowing from electrode 48 to center tap 73.

In the embodiment of FIGS. 6 and 10, a portion of the current flowing down the first confinement coil section 41 also flows through the molten metal pool 38. On the other hand, in the embodiment of FIG. 5, the portion of the current flowing through the molten metal pool 38 is not the portion of the current flowing through the portion of the confinement coil 40.

The horizontal magnetic field generated by the time-varying current flowing through the confinement coil 40 and the current flowing through the molten metal pool 38 cooperate to push the molten metal pool 38 inward from the opening end 36 of the gap 35 inward. Generate pressure.

Referring again to FIG. 7, the first confinement coil section 41 has a front surface 76, a rear surface 77, and opposed side surfaces 78 and 7.
9. Side surface 78 and back surface 77 of the first coil unit
Surrounding the side surface 79 is a magnetic member 82 which is electrically insulated from the first confinement coil portion 41, typically by an insulating thin film (not shown). Magnetic member 80
Typically comprises a conventional magnetic material and defines a low reluctance return path to a magnetic field generated by a time-varying current flowing through the confinement coil 40.

The magnetic member 80 has a pair of arms 81 and 82, each of which faces the opposing side surfaces 78 and 7 of the first coil 41.
9, each having an open end 36 of a gap 35.
And the first and second confinement coil portions 4
1,42.

The structural arrangement employed for the coil sections 41, 42 is described in detail in the aforementioned Gerber et al. US Pat. No. 5,197,534, the disclosure of which is incorporated herein by reference. However, Gerber et al., U.S. Pat.
Unlike the device disclosed in 197,534, the device of the present invention does not have a magnetic shield outside the magnetic arms 81,82. Such a shield is employed to confine the magnetic field generated by the confinement coil near the open end 36 of the gap 35. This is important in devices that rely on the induced eddy currents in the pool 38 as the primary current source of the horizontal magnetic field generated by the current flowing through the pool 38. However, in the present invention, the conduction current is the main current source of the horizontal magnetic field generated by the current flowing through the molten metal pool 38. Thus, the magnetic shield of Gerber et al., US Pat. No. 5,197,534 is not required.

As described above, the electrode 48 is
It is arranged above the nip 39 between the first and the second 32 (FIG. 2). The electrodes 48 are made of an electrically conductive material that withstands the high temperatures of the molten metal pool 38 that is at least partially immersed.
The electrode 48 is made of, for example, graphite.

The casting rolls 31, 32 are made of copper, copper alloy, ceramic, or austenitic (non-magnetic) stainless steel.

[0062] Casting rolls made of ceramic are not very conductive. In such a case, the molten metal pool 38
Suitable electrical connections to the brushes 46, 47 and plate 37
Is through. Preferably, a spring is used to bring the brush into contact with the plate 37, such a spring being represented at 85 in FIG.

If the casting roll is made of an electrically powered material such as copper or a copper alloy, a suitable electrical connection to the molten metal pool 38 includes a casting roll. In other words, the proper electrical connection is between the brushes 46, 47 and the roll 31,
32, and there may additionally be a connection between the brush and the plate 37. If the appropriate electrical connection is a brush and a casting roll, it is preferred to employ a spring 86 to press the brush against the casting roll, such a spring being represented at 86 in FIG.

The brushes 46 and 47 are made of a conductive material such as graphite or phosphorous copper.

If the brush is made of a material (such as phosphor bronze), it is cooled internally. When the brush is made of graphite, it is effective to employ a brush holder that is internally cooled. Cooling arrangements of the type described in the preceding part of this paragraph are prior art.

The above detailed description has been given for clarity of understanding only, and no unnecessary limitations should be understood from this, as modifications will be apparent to those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a view showing an end of a continuous plate casting apparatus employing one embodiment of an electromagnetic confinement device of the present invention.

FIG. 2 is a partial plan view of the structure of FIG.

FIG. 3 is a partially cutaway enlarged view of an end portion of the structure of FIG. 1;

FIG. 4 is a partially cutaway enlarged view of an end portion similar to FIG. 3;

FIG. 5 is a schematic diagram of an embodiment of a confinement device using an alternating current.

FIG. 6 is a schematic view of another embodiment of the confinement device using alternating current.

FIG. 7 is a partial cutaway plan view showing the directions of current and magnetic field associated with the device of the present invention.

FIG. 8 is a partially cutaway enlarged view showing an end of the device of the present invention.

FIG. 9 is a partially cutaway enlarged view showing an end of the device of the present invention.

FIG. 10 is a schematic diagram showing an embodiment of a confinement device using direct current.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 30 ... Electromagnetic confinement apparatus 31, 32 ... Casting roll 33 ... Gap 35 ... Gap 36 ... Open end 37 ... Plate 38 ... Melt pool 39 ... Nip 40 ... Coil 41 ... First confinement coil part 42 ... Second confinement coil Part 46, 47 ... Brush 48 ... Electrode

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B22D 11/01 B22D 11/06 330 B22D 45/00

Claims (22)

(57) [Claims] 1. Preventing leakage of molten metal through the open end of a vertically extending gap between two horizontally spaced members between which a pool of molten metal is located. An electro-magnetic confinement device comprising: an electro-conductivity device disposed near said gap for generating a first horizontal magnetic field extending toward said pool of molten metal through said open end of said gap. Confining coil means, wherein the confining coil means is spaced apart from a first confinement coil portion vertically disposed facing the open end of the gap and a back surface of the first confinement coil portion. And a second confinement coil portion which is electrically connected to the first confinement coil portion and is vertically arranged, and the time-varying current flows through one of the confinement coil portions to the first vertical confinement coil portion. Head in the direction Next, a first conductive means for generating a first horizontal magnetic field near an opening end of the gap by being directed to a second vertical direction opposite to the first vertical direction via the other of the coil portions. Through the molten metal pool in the vicinity of the opening end of the vertically extending gap, using the time-varying current as a conduction current in a direction opposite to the direction of the current flowing through the first coil portion. And a second conducting means for generating a second horizontal magnetic field in the vicinity of the opening end of the gap in the direction of. The confining coil portion and the first and second conducting means A containment device comprising means for cooperating to provide a magnetic repulsion pressure that pushes the molten metal back from the open end of the gap in the presence of the pool. 2. Apparatus according to claim 1, wherein said spaced horizontally arranged members comprise a pair of casting rolls rotating in opposite directions of an apparatus for continuously casting plates. The casting roll has a nip at the bottom of the vertically extending gap therebetween, and the oppositely rotating rolls solidify the metal from the molten pool into a continuous plate extending downward from the nip. An apparatus having means for causing 3. A transformer according to claim 2, including a main coil means for receiving an input current, and at least one auxiliary coil means connected to said first and second conducting means. An apparatus having means. 4. The apparatus according to claim 3, wherein the second
The conduction means of the above, at a position below the nip near the open end of the gap,
(a) a brush means electrically connected to at least one of the plate and (b) a casting roll, and electrically connected to the molten pool at a position above the nip near an open end of the gap. An electrode means for: 5. The device according to claim 4, wherein the first vertically disposed confinement coil has an upper end and a lower end, and the second confinement coil is a single coil. Wherein the first conducting means comprises means for directing current from the single auxiliary coil of the transformer to an upper end of the first confinement coil portion, and wherein the second conducting means comprises An apparatus for electrically connecting a lower end of the first confinement coil section to the brush means. 6. The apparatus according to claim 4, wherein the vertically disposed first and second confinement coil sections have an upper end and a lower end, and wherein the transformer is the second auxiliary coil means. Has a pair of separately divided auxiliary coils, each of the auxiliary coils of the transformer has a pair of ends, the first conducting means comprises: (a) one of the auxiliary transformer coils; First means for electrically connecting the end to the upper end of one vertically arranged confinement coil section; and (b) the other end of the one auxiliary transformer coil being vertically arranged to the other. Second means for electrically connecting to the upper end of the confined coil section, wherein the second conductive means connects one end of the other auxiliary transformer coil to the (i) The brush means and (ii) one line for electrically connecting to one of the electrode means; Conducting means, the other end of the auxiliary transformer coil, (i) said brush means and (ii) the other further having apparatus other line electrically connected to said electrode means. 7. The apparatus of claim 6, wherein said first electrical connection means of said first conducting means connects said one end of said one auxiliary transformer coil to said first vertical connection. Means for electrically connecting to the upper end of the confinement coil section disposed in the first conductive means, the one line of the second conducting means connects the one end of the other auxiliary transformer coil An apparatus having means for electrically connecting to said brush means. 8. The apparatus according to claim 4, wherein said electrode means is disposed between said casting rolls above said nip for at least partially immersing said pool of molten metal. A device having the means of 9. The apparatus according to claim 8, wherein said electrode contains graphite. 10. The apparatus of claim 4, wherein each of the casting rolls contains at least one of (a) copper and (b) a copper alloy, wherein the apparatus contacts a brush with the roll. A device having means for pressing to force it. 11. The apparatus according to claim 4, wherein each of said casting rolls contains a ceramic material, and wherein said apparatus has means for pressing a brush against said plate. 12. Apparatus according to claim 10 or 11, wherein the brush means comprises one of (a) graphite and (b) phosphor bronze. 13. The apparatus according to claim 4, wherein each of said casting rolls contains austenitic stainless steel. 14. The apparatus according to claim 1, wherein a pair of side surfaces facing the first vertically arranged confinement coil portion and a return path of low reluctance of the first magnetic field are defined. Means comprising a magnetic material, wherein the means comprising a magnetic material comprises: (a) located on each of opposing sides of the first confinement coil section;
A pair of arms extending in the direction of the open end of the gap, and (b) first and second vertically extending arms extending between the arms.
A connection located between the confinement coil portions of the device, wherein there is no magnetic shield outside the arm of the device. 15. The apparatus according to claim 1, wherein the second horizontal magnetic field strengthens the first horizontal magnetic field,
A device for increasing the pressure of the magnetic repulsion at the open end of the gap. 16. An electromagnetic device for preventing the molten metal from leaking between two horizontally spaced members between which the molten metal is located through the open end of a vertically extending gap. A method of confinement, comprising: a first vertically disposed confinement coil facing the open end of the gap; and a back surface of the first confinement coil electrically connected to the first confinement coil. An electrically conductive confinement coil having a vertically disposed second confinement coil portion facing at a distance from the first confinement coil portion, wherein a time-varying current through one of the confinement coil portions is directed in a first vertical direction. First, and then toward the pool of molten metal through the open end of the gap in a second vertical direction opposite the first vertical direction through the other of the confinement coil portions. Horizontal magnetic field Generating the time-varying current as a conduction current, vertically through the melt pool near the open end of the gap, in a direction opposite to the current through the first confinement coil section, Generating a second horizontal magnetic field near the open end of the method, wherein the preceding steps cooperate to generate a magnetic repulsion pressure that pushes the molten metal back from the open end of the gap inward. 17. The method of claim 16, wherein said second horizontal magnetic field enhances said first horizontal magnetic field to increase magnetic pressure at said open end of said gap. 18. The method according to claim 16, comprising a magnetic material, providing a low reluctance return path for the first magnetic field, and employing a magnetic shield for the return path. Not the way. 19. The method of claim 17, wherein the current is directed downward through the first confinement coil portion, and the current is split into two upon exiting the first confinement coil portion. Directing a first portion of the split current upward through the second confinement coil portion, and directing a second portion of the split current upward as the conduction current through a pool of molten metal. . 20. The method of claim 16, wherein a first current is directed downwardly through the first confinement coil section to provide a second current without passing through the confinement coil means. A method wherein the second current is directed upward through a pool of molten metal as a conduction current. 21. The apparatus of claim 1, wherein the time-varying current is an alternating current. 22. A method according to claim 16, wherein, the method varying current the time is AC.