JPH11216552A - Electromagnetic meniscus control device of continuous casting and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for magnetically control a meniscus to be formed at a position where a top face of molten metal pool contacts with rolls which are facing each other. SOLUTION: A strip casting device 46 has surfaces 57, 60 which are facing each other and a pair of rolls 49, 52 which rotate in opposite directions. Between these rolls, a space spreading in a vertical direction is formed to maintain a molten metal pool 65 having a top face 73. The meniscus 75 is formed at a position where the top face of the molten metal pool 65 contacts with each of roll faces 57, 60 which are facing each other. Various means for electromagnetically controlling time meniscus 75 are to be proposed. In one embodiment, the electromagnetic force to control the meniscus 75 is produced by an electrical conductive property coil 82 in which the time-vary electric current flows. In another embodiment, a magnetic member is provided with a coil in order to give an effect to the electromagnetic force to be produced by the coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method and apparatus for electromagnetically controlling molten metal, and in particular, to electromagnetically control the top surface of a pool of molten metal between two continuous strip casting rolls. And an apparatus for the same.

[0002]

2. Description of the Related Art An example of an operation mode to which the present invention is applied is as follows.
A process for continuously casting molten metal directly into strip (eg, steel strip). Typical of such devices are horizontally spaced ones.
It comprises a pair of rolls, each roll configured to rotate in opposite directions about a horizontal axis of rotation. The two rolls typically consist of steel or copper. 2
The rolls are arranged horizontally and have a gap extending vertically to receive the molten metal. The gap formed by the two rolls is precisely tapered downward. The side wall of the pool is enclosed by mechanical or electromagnetic means.

[0003] The molten metal in the gap forms a pool having a top surface. Typically, molten metal is supplied to the pool by a dip nozzle having an outlet below the top surface of the pool. The roll is cooled, and the roll cools the molten metal as it descends through the gap.

The meniscus is formed at a position where the top surface of the pool of molten metal contacts the roll surface (meniscus position). In the meniscus, the pool tapers downward, forming a valley on the roll surface. The meniscus is characterized by the angle β formed between the meniscus and the roll surface. When the meniscus angle (β) is relatively large, as in conventional casting equipment, the surface properties of the strip deteriorate.

[0005] In addition to the degradation of the surface properties of the strip, the thickness of the strip cast with conventional equipment is not uniform.
A wave of molten metal forms near the outlet of the nozzle in the pool and radiates from the nozzle. As the wave reaches the surface of the roll, the portion of the wave that contacts the roll solidifies. The crest reaches the roll surface higher than the wave trough. Since the crest reaches a relatively high position on the roll surface,
The molten metal at the crest has a longer cooling and solidifying time than the molten metal at the valley. As a result, the thickness of the strip formed when the crest portion contacts the roll is greater than the thickness of the strip formed when the valley contacts the roll. Thus, the occurrence of the waves causes the strip thickness to be non-uniform. A non-uniform strip thickness will increase the wave amplitude.

Since the molten metal at the crest has a longer cooling time than the molten metal at the trough, the molten metal at the crest has a lower temperature than the molten metal at the trough. If the temperature of the molten metal in the crests and valleys is not equal, stress may be generated in the strip and cracks may form along the length of the strip.

[0007] If the side wall of the pool of molten metal is confined by an electromagnetic field consisting of a horizontal magnetic field, additional waves at the top of the pool will cause a horizontal confinement field and a vertical field induced by the confinement field on the side wall of the pool. It is formed by interaction with eddy currents in the direction. The pool is agitated by the eddy currents, causing a waterfall effect (ie, a vertical flow of molten metal along the sidewall) on the molten metal sidewall.

[0008] To reduce the meniscus angle (β) and attenuate the waves, conventional casting equipment uses surface boards. The front board has a concave curved surface to complement the convex curved surface of the roll, and is disposed adjacent to the roll. The molten metal located between the faceboard and the roll has a smaller meniscus angle (β) than without the faceboard. The surface board also attenuates waves of molten metal by providing a barrier that prevents the waves of molten metal from mechanically contacting the roll. However, since the surface board is a consumable item and can withstand only a little heat,
Manufacturing steel strips with equipment that uses surface boards will result in significant cost increases.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to solve the above-mentioned problems that occur when casting a strip. The present invention relates to a strip casting apparatus and a casting method. In particular, it is an object of the present invention to provide an apparatus and method for magnetically controlling a meniscus formed at a position where the top surface of a pool of molten metal contacts rolls facing each other.

[0010]

In order to achieve the above object, the present invention is characterized by forming an electromagnetic field that performs one or more functions described below. One such function is to reduce the amplitude of waves adjacent to the meniscus location. Another function is to create a barrier between the waves and the roll surface adjacent the meniscus location. Yet another function is to control the meniscus angle.

The structure for controlling the meniscus is adjacent to the meniscus position and is outside the roll at the meniscus position and generates an electromagnetic field acting on the top surface of the pool adjacent to the meniscus position to control the meniscus. I do.
The structure for controlling the meniscus has a conductive coil, through which a time-varying current flows to form an electromagnetic field.

In addition, the electromagnetic field is placed sufficiently close to the meniscus position so that the electromagnetic field can perform one or more of the functions described above without being affected by a magnetic member that affects the magnetic field. As can be produced, the conductive coil has a coil portion adjacent to the meniscus location. Further, a magnetic member having a high magnetic permeability is used to form an electromagnetic field capable of performing one or more of the functions described above with a smaller current than a current without the magnetic member. can do. When having mechanical side wall control means, the structure for controlling the surface waves extends along the top surface of the side wall of the pool of molten metal.

[0013] Other features and advantages are as set forth in the claims and detailed description, which will be apparent to those skilled in the art from the detailed description based on the accompanying drawings.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 to 3, reference numeral 40 denotes an electromagnetic meniscus control device of the present invention for electromagnetically controlling a meniscus formed by a continuous strip casting device 46. The continuous strip casting apparatus 46 is a general strip casting apparatus having a first roll 49 and a second roll 52 rotating in opposite directions. The first roll 49 and the second roll 52 have mutually facing surfaces 57 and 60, respectively, which allow the pool 65 of molten metal to be present.
Is defined. A nozzle 70 (FIG. 3) for supplying molten metal to the pool 65 is arranged between the rolls 49 and 52. Pool 6 of molten metal
5 has a top surface 73 and a meniscus 75 is formed adjacent to a meniscus position 79 where the pool top surface 73 contacts the roll surfaces 57 and 60.

The apparatus 40 has equipment 76 adjacent to the meniscus location 79 for generating an electromagnetic field that acts on the top surface 73 of the pool to control the meniscus 75. As shown in FIG. 1, the equipment 76 includes a conductive coil 82.
And a device 85 electrically connected to the coil 82 so that a time-varying current can flow through the coil 82 to generate an electromagnetic field. As will be described in more detail later, the conductive coil 82 is a copper tube through which water flows to cool the coil 82. The device 85 is shown schematically in FIGS. 1 and 2 and comprises a conventional power supply or a power supply capable of carrying an appropriate amount of current. Coil 82 is similar to the loop used for electromagnetic containment during vertical casting of aluminum. Such a loop is disclosed in U.S. Pat. No. 4,982,796 or 4,905,756.
And cited herein for reference.

The principle of controlling the meniscus 75 is an electromagnetic repulsion. The current flowing through the coil 82 creates an electromagnetic field around the coil. The magnetic field is represented by the lines of equivalent magnetic force 86 in FIGS. 3A and 4A. The path of the magnetic flux is shown at 87. The strength of the magnetic field is increased by increasing the current through coil 82.

As shown in FIG. 4B, the electromagnetic repulsion force or magnetic pressure F at a specific position is determined by the magnetic field strength B at that position and the eddy current i induced by the magnetic field at the metal at that position. _It is proportional to the product of _e . The position represented in FIG. 4 (b) is shown as 89 in FIG. 4 (a). Electromagnetic repulsive force F at the meniscus position 79 is proportional to the product of the magnetic field strength B at the meniscus position 79, the eddy current i _e induced in the meniscus 75 by the magnetic field at the meniscus position 79. For eddy current i _e is generated by the magnetic field, an electromagnetic repulsive force F is proportional to the square of the magnetic field strength B. The magnetic pressure F is represented by B ² / (2μ) where μ is the magnetic permeability of the molten metal. The permeability will be described later in more detail. The magnetic pressure F at a particular position pushes up the molten metal in a direction perpendicular to the tangent to the line of equivalent magnetic force at that position and perpendicular to the eddy current shown in FIG.

The strength of the magnetic field is determined by the pool 65 of molten metal,
The relationship is inversely proportional to the distance from the coil 82 that generates the electromagnetic field. Thus, the pool 65 of molten metal and the coil 8
2, the magnetic field strength B in the pool 65 becomes half of the previous strength, and the magnetic pressure F becomes
It becomes １ ／ of the previous size (F∝B ² ).

The top surface 73 of the pool is provided with a nozzle 70 (FIG. 3).
Wave 88 formed by molten metal emanating from (a))
(FIG. 4A, FIG. 5, FIG. 6). Wave 88
Usually, it moves toward the meniscus position 79. As is clear from FIG. 6, the wave 88 has a continuous wave front 91 and a valley 94, and the molten metal contacts the surface of the roll (the surface 57 of the roll 49 in FIG. 6). Since the molten metal of the wave front 91 contacts the roll surface 57 longer than the molten metal of the valley 94, the molten metal of the wave front 91 has a longer solidification time than the molten metal of the valley 94. Since the coagulation time is not uniform, the thickness of the strip in the width direction of the strip is not uniform. Further, the greater the amplitude of the wave 88, the greater the variation in strip thickness due to the uneven surface of the strip. Further, since the molten metal of the wave front 91 is in contact with the roll surface 57 longer than the molten metal of the valley 94, the cooling time of the molten metal of the wave front 91 is longer than that of the molten metal of the valley 94. Therefore, the molten metal at the crest 91 is lower in temperature than the molten metal at the valley 94. The temperature difference between the crests 91 and the valleys 94 can cause stress in the strip, which can crack along the longitudinal axis of the strip.

To improve the surface quality and thickness uniformity of the strip, a coil 82 (not shown in FIG. 6) is used to generate an electromagnetic field that reduces the amplitude of the wave 88 adjacent the meniscus 75. used. FIG. 4A shows the configuration of the coil 82.
Shows that the wave 88 is attenuated by the electromagnetic field due to. FIG. 5, on the other hand, shows an undamped wave 8 in a casting machine without a coil 82 or other source of electromagnetic force for damping the wave.
8 is shown.

As shown in FIGS. 7 and 8, the top surface 73 of the pool at the meniscus position 79 and the roll surface 57 adjacent to the meniscus position 79 define a meniscus angle (β). The coil 82 generates an electromagnetic field for controlling the meniscus angle β. Decreasing the meniscus angle β can improve the surface quality of the strip. FIG. 7 shows a case where the meniscus angle β is relatively small due to the magnetic pressure generated by the magnetic field generated by the coil 82. on the other hand,
In FIG. 8, the meniscus angle β is relatively large because there is no coil 82 or other electromagnetic force source that reduces the angle β.

Another means of solving the strip surface non-uniformity caused by the waves 88 is to form a barrier. The coil 82 is used to generate an electromagnetic field to form a barrier between the wave 88 and the roll surfaces 57,60. As shown in FIG. 4A, the electromagnetic field generated by the coil 82 is interposed between the wave 88 and the roll surface, and the wave 88 is applied to the roll surface (57 in FIG. 4A).
To avoid reaching.

As shown in FIG. 1 and FIG.
2 has a coil portion 97 adjacent to the meniscus position 79 to generate an electromagnetic field sufficiently close to the meniscus position 79. As a result, the electromagnetic field may have any of the functions described above, ie, attenuating the molten metal wave 88, controlling the meniscus angle β, or forming a barrier between the wave 88 and the roll surfaces 57, 60. Make it possible. The coil 82 is made of a conductive material such as copper. The cross section of the coil 82 is annular as shown in FIG. 3 (a), but may be rectangular, square, triangular, elliptical or any other suitable shape for conducting electricity. The illustrated coil 82 is hollow to allow cooling water to circulate within the coil. Cooling water is supplied to coil 8
2 is necessary when the amount of heat generated by the frequency of the magnetic field generated by it is too great and air cooling is insufficient.

In general, a magnetic field strength of at least about 100 gauss at the surface 73 of the molten metal is sufficient to control the meniscus 75. The distance between the coil 82 and the meniscus 75 is about 0.25 to 1 inch (6.5 to 2 inches).
5.4 mm) and a current of about 200-1000 amps provides sufficient magnetic field strength for favorable control over meniscus 75. Of course, the effect of the distance from the meniscus 75 changes according to the magnitude of the current flowing through the coil 82. When the meniscus 75 is unaffected by the electromagnetic field, a portion of the meniscus 75 furthest from the roll surface (e.g., the roll surface 57) is about 4-12 mm from the roll surface. Meniscus 75
However, because it is about 4-12 mm away from the roll surface, a strong magnetic field must be oriented so as to be very close to the roll surface in order to control the meniscus 75.
When unaffected by electromagnetic fields, the maximum distance the meniscus 75 is away from the roll surface depends on the rotational speed of the rolls 49, 52 and other variables.

The leakage flux is shown in the figure as 98 (in FIG. 3 (a) and in the following figures) and is not effective for controlling meniscus or wave attenuation.

When the coil 82 is near the top surface 73 of the pool 65 of molten metal, the molten metal may scatter on the coil 82. To protect the coil 82, the coil 82
Is coated with a splash guard 100, such as ceramic, or other non-conductive material, as shown in FIG. 3 (b). If the distance between the coil 82 and the top surface 73 of the molten metal had to be increased to cover the splash guard 100, the current required to obtain a particular magnetic field strength at the meniscus location 79 would be: Need to increase.

The roll and the pool have a magnetic permeability μ.
μ is a measure of the material's ability to focus the magnetic field lines, similar to the magnetic conductivity of magnetic flux. Rolls and pools also have a resistivity ρ. The alternating magnetic field has a frequency f equal to the frequency of the time-varying current. When an alternating magnetic field is applied to the surface of a conductive material having a resistivity ρ and a magnetic permeability μ, the density of the magnetic field and the eddy current in the material is weakened, and the phase is shifted when the magnetic field and the eddy current penetrate the material. The magnetic flux is equal to the strength of the magnetic field at the surface.
The distance δ from the surface of the material that is weakened to 367 is called the skin thickness (δ) defined by the following equation:

The magnetic flux that decays exponentially in the material δ = (ρ / μπf) ^1/2 is equivalent to an imaginary uniform electromagnetic field contained within the skin thickness δ of the material. In steel at the melting point, ρ is about 140 microΩ
・ It is cm. In a water-cooled copper roll, ρ is about 1.73.
It is microΩ · cm. The skin thickness (δ) at different frequencies (f) for the molten metal (Fe) and room temperature copper (Cu) is as shown in Table 1.

[0029]

[Table 1]

[0030] The melting point of the steel is well above the Curie temperature of about 700 ° C, and even when casting low carbon steel, the molten metal becomes non-magnetic. The Curie temperature is defined as the temperature at which the steel loses magnetism.

As the skin thickness decreases, the electromagnetic stirring or electromagnetic agitation of the molten metal decreases, and the meniscus 75
Control becomes better. The high frequency magnetic field only reaches a shallower place than the low frequency magnetic field. At a frequency of 10,000 Hertz, the agitation hardly ripples the top surface 73 of the pool. At 300 Hertz, the agitation becomes violent, often rippling the surface unbearably.

A disadvantage of high frequencies is that heat is generated by eddy currents. Power consumption per unit area (P / A) in the pool of molten metal is P / A = ρ · (B / μ) ² / (2δ). Power consumption at any magnetic flux density (B) is inversely proportional to skin thickness (δ). Since skin thickness (δ) is inversely proportional to the square root of frequency (f), power consumption is proportional to frequency (f).

Table 2 below shows the power consumption by eddy currents for molten metal (steel) and room temperature copper rolls at 100 Gauss surface magnetic field strength (B).

[0034]

[Table 2]

In particular, at the relatively low magnetic field strengths shown in Table 2 (100 gauss), it is advantageous to operate the electromagnetic meniscus control facility 76 at a high frequency above 3 kHz to reduce agitation. Coil 82 is 100
When generating a Gaussian magnetic field, as shown in Table 2, the heat on the copper roll surfaces 57, 60 at these frequencies is negligible.

Typically, rolls 49 and 52 are cooled with water circulating inside the rolls to facilitate solidification of the strip at roll surfaces 57,60. Generally, roll 49 in strip casting,
52 is cooled by the pool of molten metal 65 rolls 49, 5.
Necessary to be the second heat source. Then, in the continuous casting of the strip, it is preferable to cool the rolls 49 and 52.

The general cooling structure for cooling the rolls 49, 52 is sufficient to cool the rolls 49, 52 exposed to a magnetic field by the coil 82 as a heat source. When the coil 82 is used, the roll surface 57,
If too much heat is generated at 60, the coil 82 will cause the surface of the roll 5
It is arranged relatively far away from 7,60. However, a magnetic field having a strength of substantially 100 Gauss or more heats the roll surfaces 57,60.

The heating position of the roll surfaces 57 and 60 by the coil 82 is preferably a meniscus position 79. This is because such heating increases the uniformity of the surface of the strip. When the roll surfaces 57, 60 are heated, the solidification of the molten metal wave front 91 (FIG. 6) is delayed. As a result, the difference between the clot time of the crest 91 and the clot time of the valley 94 (FIG. 6) is reduced. Any one or more of the following methods can be employed to increase the amount of heating of the roll surfaces 57, 60: placing the coil 82 relatively close to the roll surfaces 57, 60; Increasing the current flowing, increasing the frequency of the magnetic field.

As mentioned above, rolls 49, 52 are typically made of copper or steel. Another way to increase the amount of heating of the roll surfaces 57, 60 is to manufacture the rolls 49, 52 from a material that has a lower thermal conductivity, lower electrical conductivity, or higher magnetic permeability than copper or steel. . For example, a copper roll can be coated with nickel or a nickel-based alloy. When exposed to the same magnetic field, a nickel coating, which has a lower thermal conductivity than copper or steel, a lower electrical conductivity than copper, and a higher permeability than copper or steel, has a roll surface temperature higher than that of a copper or steel roll. Get higher.

In another embodiment, shown in FIGS. 9-11 (b), coil 82 includes first and second coil portions 10
3 and 106, which are electrically connected to each other and adjacent to the meniscus position 79. 9 to 11
As shown in (b), the second coil part 106 is arranged substantially parallel to the first coil part 103. The second coil portion 106 can also be arranged in the opposite direction with respect to the first coil portion 103. As can be seen, coil 82 is shown as solid in FIG. 9 and is hollow in FIGS. 11 (a) and 11 (b).

The magnetic field is shown as equivalent magnetic field lines 109 in FIG. In FIG. 11 (b) and subsequent figures having the first and second coil portions, the direction of the current is shown as an "X" at the center of one coil portion and a "point" at the center of the other coil portion. It is shown as The symbol “X” indicates that the current flows toward the plane of the drawing, and the “dot” symbol indicates that the current flows outward from the plane of the drawing.
The direction of the magnetic field around the coil portion can be determined by applying the so-called right-hand rule to the direction of the current flowing through the coil portion.

In FIG. 11B, the equivalent magnetic force lines 109
And the gap 111 between the first coil portion 103 and the second coil portion 106, the magnetic field generated by the first coil portion 103 and the second coil portion 106 runs in the same direction. Thus, the first coil portion 103
In the gap between the first and second coil portions 106, the magnetic fields generated by the respective coil portions reinforce each other.

The coils in FIGS. 1 to 4 (a) are called wide loop coils. This is because the area surrounded by the coil 82 in FIGS. 1 to 4A is relatively large and extends in the width direction of the top surface 73 of the pool 65. In contrast, the coil 82 in FIGS. 9-12 forms two narrow loops 110 (FIGS. 10 (a), 10 (b)), each loop 110 surrounding a relatively small area.
The wide loop coil tends to generate an eddy current on the entire top surface of the pool, and has a higher inductance than that of the narrow loop. In the case of the narrow loop, the required voltage and current are lower than in the case of the wide loop.

9 to 12, the gap (gap 111) between the coil portions 103 and 106 is much smaller than the gap 112 surrounded by the wide loop coil 82 of FIG. The magnetic field lines of FIG. 3 (wide loop) and FIG. 11 (b), FIG.
9 (narrow loop), FIG.
It can be seen that in the case of the narrow loop, the magnetic field lines are concentrated in a very small space. Also, the eddy current loss and the eddy current mixing are limited to a narrow space.

The inductance L of the current loop is approximately proportional to the area surrounded by the conductor. therefore,
The inductance of the narrow loop of FIGS.
Much less than the wide loop inductance.

The power loss in the resistance of the system is equivalent to the loss in the coil conductor and the eddy current loss in the molten metal as the eddy current flows within the skin thickness of the molten metal surface. The loss in the coil conductor is equal to I ² R, where I is the current through the coil and R is the resistance of the coil. Eddy current loss, (I _e) equal to ² R _e, Ie is the eddy currents flowing in the molten metal, Re is the resistance of the molten metal. The embodiment of FIG. 4 (wide loop) and FIGS.
If the same current is required to control the meniscus using the second embodiment (narrow loop), the required power is roughly proportional to the inductance L of the circuit. Since the inductance L of the narrow loop embodiment (FIGS. 9-12) is much smaller than the inductance of the wide loop embodiment (FIGS. 1-3), the power required for the embodiment of FIGS.
Is much smaller than that of the embodiment.

In particular, the first and second coil portions 10
The embodiment of FIGS. 9-12 with 3, 106 is required by the embodiment of FIGS. 1-4 (a) without a second coil portion for generating a magnetic field of specific strength at meniscus location 79. Less than about 1/3 of the voltage / current value.

In the embodiment of FIGS. 9-12, a plane 118 bisecting both coil portions 103 and 106 (FIG. 11B).
11 and 12) affect both the electromagnetic force reaching the meniscus position 79 and the electromagnetic force acting on the top surface 73 of the pool away from the meniscus 75, as shown in FIGS. 11 (b) and 12.

For example, as shown in FIG. 12, the second coil portion 106 is located at substantially the same height as the first coil portion 103 with respect to the top surface 73 of the pool. In order to control the meniscus more effectively, the coil portion 1
03, 106 should have a position and direction such that some of the lines of magnetic force of the electromagnetic field are toward meniscus position 79. This corresponds to the embodiment of FIGS.
Is achieved.

First coil portion 103 and second coil portion 1
Each of 06 may be covered with a protective layer or splash guard 100 as described for FIG. Alternatively, a single splash guard can cover both coil sections. The device of FIG. 13 is a single wide loop device. The embodiment shown in FIG. 14A corresponding to the device 40 of FIG. 13 has a pair of magnetic members 121. Each magnetic member is coupled to at least a part of the coil 82 and is disposed adjacent to the roll surfaces 57 and 60 (only the roll surface 57 is shown in FIG. 14A). In FIG. 13, each magnetic member 121 has an inverted U
It is represented by a letter-shaped yoke and arm. FIG. 14 (a)
As shown in FIG. 3, each magnetic member 121 is provided with a pair of arms 12.
7 has a yoke 124 connected thereto. Arm 12
One or both 7 are substantially perpendicular to the yoke 124.

Each arm 127 terminates at a magnetic pole at the outer end 128. A part of the coil 82 is received between a pair of arms of the magnetic member 121. As shown in FIG. 14A, the magnetic member 121 has a tapered portion 126 adjacent to the roll surface 57, which facilitates the magnetic pole portion 128 to be adjacent to the roll surface 57. The lines of magnetic force are shown in FIG.
(A) and in the subsequent figures having a magnetic member,
It is shown as 125.

The magnetic member 121 may be formed of a ferromagnetic steel laminate generally used as a magnetic member operating at an audio frequency of about 1000 Hz or more. Alternatively, the magnetic member 121 can be formed by tape winding of ferromagnetic steel. The magnetic member 121 may be formed of a suitable ferromagnetic member having a relatively high magnetic permeability such as ferrite. The gap between the coil 82 and the magnetic member 121 can be filled with a heat conductive electrically insulating material 120. Material 1
20 can not only electrically insulate the conductor 82 but also make the water-cooled conductor 82 a heat absorber by transmitting the heat generated by the eddy current loss in the magnetic member 121 to the water-cooled conductor 82. Alternatively, an air layer may be provided between the magnetic member 121 and the coil 82 to avoid a short circuit between the magnetic member 121 and the coil 82. In order to provide such an air layer, an appropriate structure (not shown) may be employed so as to maintain a space between the magnetic member 121 and the coil 82.

A refractory splash guard similar to the splash guard 100 of FIG. 3B can surround the magnetic member 121 and the coil 82.

The shape of the magnetic member 121 and the shape of the conductor 82 determine the shape of the magnetic field generated by the coil 82. As described above, it is preferable to use the magnetic member 121 having a shape different from that of FIG. For example, the magnetic member 121 can be provided around the coil 82 that is larger or smaller than the cross section of FIG. The magnetic member 121 and the coil 82 can be shaped to optimize a magnetic field near the meniscus position 79 and can be provided at such a position.

The embodiment shown in FIG.
It is similar to the embodiment of FIG. 4 (a) except that it has 21A. The magnetic member 121A is similar to the magnetic member 121 except that its cross section is not U-shaped but rather semicircular. The cross section of the coil 82 is shown in FIG.
Is substantially circular, while in FIG. 14A, the cross section of the coil 82 is substantially rectangular.

[0056] magnetic member 121 provides a magnetic flux path having a relative permeability mu _r of 1000 times more air. The current required to increase the magnetic flux passing through the magnetic member 121 is negligible compared to the current required to increase the magnetic flux along the magnetic flux path 129 (FIGS. 14A and 14B). Therefore, in order to generate a magnetic flux density of 100 Gauss near the meniscus position 79, it is necessary that a current flowing in the coil 82 generates a magnetic flux density of 100 Gauss in the magnetic flux path 129. Compared to the wide loop device of FIGS. 1-4, the flux path 87 (FIG. 4 (a))
It is much longer than the flux path 129 of (a) and 14 (b). The exciting current I flowing through the coil 82 is I = B · l / μ, where 1 is the length of the magnetic flux path. The current required in this way is proportional to the length l of the magnetic flux path. FIG.
A comparison of (a), 14 (a) and 14 (b) shows that the flux path 129 is shorter than half the flux path 87. By adding the magnetic members 121 and 121A to the wide loop conductor 82 shown in FIGS.
(A) (b)), the required current is reduced by less than half, and the required power (P = I ² R) is reduced by １ ／ or less. Further, the eddy current loss due to the current in the coil 82 of the apparatus of FIG.
4 of the eddy current loss due to the current in 2 and the mixing of the surface 73
More than double.

The magnetic member provides a region having a high magnetic permeability in which a current flows more easily in a magnetic field than air. In fact, the magnetic member 121 replaces air with a relatively low magnetic permeability. The lines of magnetic force flow through the yoke 124, one of the arms 127, and the other of the arms 127. Although the magnetic field of the embodiment of FIGS. 14A and 14B has air in a part of the path (magnetic flux path 129) in the magnetic field, the magnetic member 121
9, thus increasing the strength of the magnetic field at meniscus position 79 for a particular current.

The magnetic member 121 has such a shape that part of the magnetic member 121 does not exist between the coil 82 and the meniscus position 79, and is arranged at such a location. If a part of the magnetic member 121 is the coil 82 and the meniscus position 7
9 between the magnetic member 12 and the magnetic member 12.
1, and few lines of magnetic force reach the meniscus position 79. As described above, since the magnetic member 121 has a higher magnetic permeability than air,
The lines of magnetic force easily flow through the interior of the device. Thus, FIG.
Both ends 128 of the arm 127 shown in FIG. 11B are separated from each other, and the magnetic member 121
9 so that a part of the magnetic member 121 does not exist, and is disposed at such a location. In these example arrangements, which emit the coil 82 and create a magnetic field line that flows between both ends 128 of the arm 127, the meniscus is less than when a portion of the magnetic member 121 is present between the meniscus position 79 and the coil 82. The lines of magnetic force concentrate toward position 79. Also, the arrangement of these embodiments produces an electromagnetic field that is more concentrated at the meniscus position 79 than without the magnetic member 121.

As described above, in all embodiments where a magnetic member is coupled to a coil or coil portion so as to form a magnetic field near the meniscus 75 and increase the strength of the magnetic field, the magnetic member is a magnetic member. Is located between the coil or coil portion and the meniscus position 79 and is shaped so that the ability of the magnetic field to control the amplitude of the wave and the angle of the meniscus is not impaired, and is located at such a location. Is done.

The magnetic member 121 functions as described above (ie, attenuates the molten metal wave 88, controls the meniscus angle β, or creates a barrier between the wave 88 and the roll surfaces 57, 60). ) To direct the magnetic field in a direction in which the magnetic field can fulfill either of the above.

In the embodiment shown in FIGS. 14A and 14B, the magnetic flux path 129 between both ends 128 of the arm 127 is a region where the magnetic field strength is maximum. 14A, one arm 127 of the magnetic member 121 is located on the meniscus 75, and the other arm 127 is located away from the roll surface 57. With such an arrangement of the magnetic member 121, the strongest magnetic field is located above the pool 65 adjacent to the meniscus 75 to efficiently control the meniscus 75.

The magnetic member 121 is provided on the roll surfaces 57 and 60.
And the top surface 73 of the pool can be arranged in the opposite direction. For example, the magnetic member 121 may be disposed above the roll top surfaces 73 and 60 adjacent to the meniscus position 79 from above the pool top surface 73. Further, the magnetic member 121 is configured such that both arms 127 are positioned at the meniscus position 79.
It can also be inclined to point to. Meniscus 7
The effect of the magnetic member 121 in various directions when controlling the number 5 partially depends on the cross-sectional shapes of the magnetic member 121 and the conductor 82 as shown in FIGS.

The current required to obtain a particular magnetic field strength at a particular location on the pool's top surface 73 depends on the magnetic member 12
If the shape of 1 changes, it changes. To obtain a specific magnetic field strength at a position adjacent to the meniscus position 79, FIG.
14 (a) and 14 (b), the voltages and currents required in the embodiment adjacent to the meniscus position 79 are the same as those in FIGS. It is about 50% or less of the voltage and current required in the embodiment. The efficiency of the embodiment of FIGS. 13 and 14 (a) and (b) is such that the magnetic flux path (magnetic flux path 129) shorter than the magnetic flux path 87 (FIG. 4 (a)) of the embodiment of FIGS. It is obtained by generating the member 121.

As shown in FIG.
Has an L-shaped magnetic member 130 having arms 131 and 132 connected together. Arms 131 and 132 terminate at magnetic poles 134a and 134b, respectively. Arms 131 and 132 are divergent and substantially perpendicular.
In this embodiment, the roll 49 is heated more than in the case of FIGS. This is because the distance in which the magnetic flux penetrates the roll surface 57 is longer in this embodiment than in the case of FIGS. The voltage and current required in the embodiment of FIG. 15 to obtain a specific magnetic field strength at a position adjacent to the meniscus position 79 will obtain the same magnetic field strength at the position adjacent to the meniscus position 79 Therefore, the voltages and currents required in the embodiment of FIGS. 14A and 14B are almost the same.

The device of FIG. 16 (a) is similar to the narrow loop embodiment of FIGS. However, in order to reduce the required current to less than half and to reduce the leakage flux, the magnetic member 13 is required.
5 is added.

FIG. 16B is an embodiment utilizing the arrangement of FIG. 16A, and has a magnetic member 135 and vertically elongated first and second coil portions 137 and 139. The second coil portion 139 is substantially parallel to the first coil portion 137 adjacent to the meniscus position 79, as shown in FIG. Arms 140 and 141 terminate in pole portions 142 and 143, respectively. Magnetic member 13
5 on the first and second sides 147, 1
50. The first side 147 of the yoke 144 and the arms 140, 141 define a groove 151 for receiving the first coil portion 137. The second coil portion 139 is adjacent to the second side surface 150 of the yoke 144 outside the groove 151.

The device shown in FIG. 16A is basically similar to the device shown in FIG.
(A) Same as the narrow loop of (b), but with a magnetic member. The device shown in FIG.
The required current is lower than the device of (b). Further, FIG.
In the embodiment shown in FIG.
2, 143 and the shape of the conductor 82.

In the embodiment shown in FIG. 16B, the arm 140 is located above the position adjacent to the meniscus position 79, and the arm 141 is located on the top surface 73 of the pool. It is located away from 79. Magnetic field containment is achieved between poles 142 and 143 in region 152 in this embodiment. When the magnetic member 135 is at the position shown in FIG. 16B, a relatively strong magnetic field is applied to a position adjacent to the meniscus 75.

The magnetic member 135 can be arranged on the opposite side with respect to the roll 49. For example, the magnetic member 135
Can also be located on the raw surfaces 57, 60 adjacent to the meniscus location 79, rather than the top surface 73 of the pool. Further, the magnetic member 135 is connected to the arms 140 and 141.
Can be inclined to point to the meniscus position 79. Magnetic member 121 for controlling meniscus 75
The effects of the various directions described above partially depend on the cross-sectional shape of the magnetic member 135 and the shape of the first coil portion 137.

The voltage and current required by the apparatus of FIG. 16A and the embodiment of FIG. 16B to generate a magnetic field of a specific strength at a position adjacent to the meniscus position 79 are equal to the meniscus. In order to generate a magnetic field having the same strength as the above-mentioned magnetic field strength at a position adjacent to the position 79, the voltage and the current required in the embodiment of FIGS. About 15% of the required voltage and current. this is,
The embodiment of FIG. 16 (b) is an arrangement of narrow loops with magnetic members, thereby creating a shorter flux path in the region 152 than the flux paths of the embodiments of FIGS.

The second coil portion 139 can be arranged on the magnetic member 135 at a position different from the position adjacent to the second side surface 150 of the yoke 144. For example, FIG.
As an embodiment similar to the embodiment of (b), the second coil portion 139 may be adjacent to the outer surface 153 of either the arm 140 or 141.

As shown in FIG. 17, the device 40 has an L-shaped magnetic member 155 having arms 157 and 159. The magnetic member 155 is composed of a tape wound iron core. The arms 157 and 159 are divergent and are substantially perpendicular. Coil portion 137 is received between arms 157 and 159. The arms 157 and 159 each terminate in a pole portion and are arranged such that the magnetic member 155 does not have an arm adjacent the side 160 of the first coil portion 137 closest to the pool 65.

Some leakage flux 98 can be seen in the coil portion 139 shown in FIG. The arrangement of FIG.
The roll 49 is heated more than in the embodiment of FIG. This is because the distance of the magnetic flux penetrating through the inside of the roll surface 57 is longer in the arrangement of FIG. 17 than in the embodiment of FIG. The voltage and current required in the embodiment of FIG. 17 to generate a magnetic field of a particular strength at a location adjacent to meniscus location 79 is
The voltage and current required for the device of FIG. 16A and the embodiment of FIG. 16B to generate a magnetic field having the same strength as the above-mentioned magnetic field strength at a position adjacent to the above are almost the same.

Another embodiment of the present invention having an L-shaped magnetic member is shown in FIGS. 18 (a), (b) and FIG. In this embodiment, the magnetic member 167 and the water-cooled vertical coil portion 16 are used.
1, 164. The magnetic member 167 is provided as shown in FIG.
It is a collection of thin L-shaped laminates as shown in (b). The magnetic member 167 has a magnetic pole portion 173,
It has arms 168 and 169 ending at 76. Arms 168 and 169 are divergent and substantially perpendicular, as shown in FIGS. An eddy current shield 170 made of copper is arranged on the outer surface of the magnetic member 167, and a thermally conductive insulating material 171 is interposed between the magnetic member 167 and the shield 170. If there is no shielding 170,
Excessive leakage flux is created around the coil portion 161.

In FIG. 18A, a coil portion 161 made of copper is brazed to an outer shield 170 to use the shield as a heat absorber. The coil portion 164 is a substantially triangular cross-section with a side 172 very close to the meniscus location 79. The coil portion 164 forms a magnetic field near the meniscus 75. Electrically insulating and thermally conductive material 1
77 is disposed between the magnetic member 167 and the coil portion 164, and the coil portion 164 acts as a heat absorber of the magnetic member 167. The magnetic pole portion 173 is shown in FIG.
As shown in FIG. 5, a plane that is tapered and substantially parallel to a tangential plane of the roll surface 57 at a position 178 on the roll surface 57 is defined. Position 178 is the position on surface 57 closest to pole portion 173.

FIG. 19 shows another embodiment in which the magnetic member 167 is used. The shield 170 is connected to each coil portion 161 and 1
64 brazed. Shield 170 and magnetic member 16
The shape of the seven magnetic poles 173, 176 determines the distribution of the magnetic flux. As shown in FIG. 19, the magnetic poles 173 and 176 are tapered so as to form a magnetic flux. Further, as shown in FIG. 19, the coil portions 161 and 164 have a substantially rectangular cross section. Alternatively, like the coil portion of FIG. 18 (a), the coil portion 161 of FIG. 19 may have a substantially circular cross section, and the coil portion 164 of FIG. 19 may have a substantially triangular cross section. Can also.

The voltage and current required in the embodiment of FIGS. 18 and 19 to form a magnetic field of a particular strength at a position adjacent to the meniscus position 79 are determined at the position adjacent to the meniscus position 79. The voltage and current required in the device of FIG. 16A and the embodiment of FIG. 16B to form a magnetic field having the same strength as the magnetic field strength are almost the same.

In the apparatus shown in FIG.
Has two narrow loops with a magnetic member 186. As shown below, the magnetic member 186 can be M-shaped (186A in FIG. 21) or T-shaped (186B in FIG. 22).

The embodiment shown in FIG. 21 has first and second coil portions 180,183. The second coil portion 183 is disposed adjacent to the meniscus position 79, and the first coil portion 180 is arranged beside the second coil portion, and a gap is provided between the second coil portion 180 and the second coil portion. The second coil portion 183 is disposed substantially parallel to the first coil portion 180, as shown in FIG. The magnetic member 186A is a laminate, and has a yoke 189, an outer first arm 192, an inner second arm 195, and an outer third arm 198. Each arm extends from yoke 189 and terminates at pole portion 199. Arm 19
2, 198, as shown in FIG.
It is tapered. At least a portion of the second coil portion 183 is received in a groove defined between the first arm 192, the second arm 195, and the yoke 189. At least a portion of the first coil portion 180 is
95, is received in a groove defined between the third arm 198 and the yoke 189.

In order to prevent the short circuit of the heat conductive and electrically insulating material 171, the coil portions 180 and 183 and the magnetic member 1
86A. The material 171 is the magnetic member 1
By transferring the heat generated by the eddy current losses in 86A to the coil portions 180,183, the water-cooled conductor 82 becomes a heat sink.

The magnetic member 186A can be used for any of the above control functions (attenuating the wave 88 of the molten metal, controlling the meniscus angle β, and forming a barrier between the wave 88 and the roll surfaces 57, 60). Arm 192, 1, to orient the field so that the field can perform
95 and a magnetic pole portion 199.
The magnetic field generated by the coil portion 183 controls the shape of the meniscus 75. The magnetic field generated by coil portion 180 attenuates the molten metal wave. Magnetic material 1
86A arms 192, 195, 198 and coil part 1
The shapes of 80, 183 can also be changed to direct the magnetic field to optimize meniscus control and attenuate the molten metal wave. The voltage and current required in the embodiment of FIG. 21 to create a magnetic field of a particular strength at a location adjacent to meniscus location 79 are
In order to form a magnetic field having the same strength as the above-mentioned magnetic field strength at a position adjacent to the device, the voltage and current required in the apparatus of FIG. 16A and the embodiment of FIG. 16B are substantially the same.

The embodiment shown in FIG.
A T-shaped magnetic member 186B having a central arm 201 between 3 and 205 is used. Arms 203 and 205
Are substantially coplanar. Arm 201 is substantially perpendicular to arms 203 and 205. The arms 201, 203 and 205 are respectively
Ends with 7. Magnetic pole part 2 of arms 203 and 205
07 is tapered. At least a part of the coil portion 183 is adjacent to the arms 201 and 203. Coil portion 183 and magnetic pole portion 20 of arms 203 and 201
7 forms a magnetic field for controlling the meniscus 75. The coil portion 180 and the pole portions 207 of the arms 205 and 201 create a magnetic field to attenuate waves of the molten metal.

The magnetic member 186B is made of a laminate. The stacked body is arranged as shown by the butt connection in FIG. 22B so that the lines of magnetic force flow in the path shown in FIG. In particular, the plane defined by the stack of arms 203 is substantially parallel to the plane defined by the stack of arms 205. The plane defined by the stack of arms 201 is perpendicular to the plane defined by the stack of arms 203,205. Alternatively, the arms 201, 203, 205 can be cut from a tape wound core and combined.

The coil portion 183 has a substantially triangular cross section. The heat conductive and electrically insulating material 171 is used to prevent the coil portions 180 and 183 and the magnetic member 1 from being short-circuited.
86B. The material 171 is the magnetic member 1
By transferring the heat generated by the eddy current loss in 86B to the water-cooled conductor 82, the water-cooled conductor 82
As a heat sink. Central arm 201 and each arm 203,
It is important to place an electrically insulating and thermally conductive material between the first and second electrodes 205 and 205.

The magnetic member 186B is capable of performing any of the above-described control functions (attenuating the molten metal wave 88, controlling the meniscus angle β, and forming a barrier between the wave 88 and the roll surfaces 57, 60). The arms 201, 2 to orient the field so that the field can be carried out.
03 and 205 and the magnetic pole portion 207. The magnetic field formed by the coil portion 183 is
The shape of the meniscus 75 is controlled. The magnetic field created by coil portion 180 attenuates the molten metal wave. The shapes of the arms 201, 203205, the magnetic pole portion 207 of the magnetic member 186B, and the coil portions 180, 183 can also be altered to direct the magnetic field to control and attenuate the waves of the molten metal. To generate a magnetic field of a specific strength at a position adjacent to the meniscus position 79, FIG.
The voltages and currents required in the embodiments of (a) and (b) are used to generate a magnetic field of the same strength as the above-described magnetic field strength at a position adjacent to the meniscus position 79. It is approximately equal to the voltage and current required in the 16 (b) embodiment.

An apparatus having an elongated first coil portion 221 and an elongated second coil portion 224 is shown in FIG. An example is shown in FIG. This embodiment includes a first magnetic member 227 coupled to the first coil portion 221;
Second magnetic member 230 coupled to second coil portion 224
have. In FIG. 24, the first magnetic member 227
Is a yoke 233 and arms 236 and 23 extending therefrom.
9. Arms 236 and 239 terminate in pole portions 250 and 252, respectively. At least a portion of the first coil portion 221 includes the yoke 233 and the arm 23
6,239. The second magnetic member 230 has a yoke 242 and arms 245 and 248 extending therefrom. Arms 245, 24
8 terminates at pole portions 254, 256, respectively. The magnetic pole portions 250, 256 are tapered as shown in FIG. At least a portion of the second coil portion 224 is received in a groove defined by the yoke 242 and the arms 245,248. The arm 239 of the first magnetic member 227 is adjacent to the arm 245 of the second magnetic member 230.

The second magnetic member has the above control functions (attenuating the wave 88 of the molten metal, controlling the meniscus angle β, and forming a barrier between the wave 88 and the roll surfaces 57, 60). Structures such as pole portions 254, 256 cooperate with the first magnetic member 227 to orient the field so that one or more can be performed by the field.

The positions of the magnetic members 227 and 230 are adjusted independently, and a magnetic field is formed near the meniscus 75 by the magnetic member 230, and a magnetic field for attenuating the wave of the molten metal is formed by the magnetic member 227. Magnetic member 227,
Numeral 230 is a tape wound or laminated body of ferromagnetic steel. The heat conductive electric insulator 171 is the coil part 2
21 and 224 and the magnetic members 227 and 230. The heat conductive electric insulator 171 causes the coil portions 221 and 224 to generate heat generated by the eddy current loss in the magnetic members 227 and 230, respectively.
1, 224, the coil portion 22
1 and 224 function as heat sinks.

FIG. 25 shows an embodiment in which the first L-shaped magnetic member 2 is used.
90A and a second L-shaped magnetic member 293. The magnetic member 290A is connected to the arm 29 connected at the connection point 302.
6 and 299. Arms 296 and 299 terminate in pole portions 305 and 308, respectively. The arms 296 and 299 are divergent and are substantially perpendicular to each other. The pole portions 305 and 308 are tapered. The coil portion 221 includes the arms 296 and 2 of the magnetic member 290A.
The side 310, which is received between 99 and is far from the meniscus 75, has a round shape. Magnetic pole portion 305,
308 and coil portion 221
A magnetic field is formed to attenuate the third wave.

The second magnetic member 293 has arms 311 and 315 connected at a connection point 318. Arm 3
11 and 315 terminate in pole portions 321 and 324, respectively. Arms 311 and 315 are branched and are substantially perpendicular to each other. Arm 311 is magnetic pole part 32
1 at right angles to the plane tangent to the roll surface (57 in FIG. 25) at position 327 on the roll surface 57. Arm 315 is parallel to a plane tangent to the roll surface (57 in FIG. 25) that includes location 327. Pole portion 321 defines a surface that is parallel to a tangent plane that includes location 327. The magnetic poles 321 and 324 and the coil portion 224 form a magnetic field that controls the meniscus 75.

FIG. 26 is a modification of the embodiment of FIG. 25 having a magnetic member 290B similar to magnetic member 290A, but having a non-tapered pole portion 308A. The coil portion 221A having a substantially circular cross section is disposed between the arms 296, 299 of the magnetic member 290B. The coil portion 224 has a substantially rectangular cross section, with the long side of the rectangle facing the adjacent roll surface (roll surface 57 in FIGS. 25 and 26), as shown in FIGS. I have. Pole portions 305 and 308A and coil portion 221A create a magnetic field to attenuate waves on top surface 73 of pool 65.

As shown in FIGS. 23-26, the second coil portion 224 is substantially parallel to the first coil portion 221 adjacent the meniscus location 79.

In order to form a magnetic field of a specific strength at a position adjacent to the meniscus position 79, the apparatus shown in FIG.
The voltages and currents required by the corresponding embodiments of FIGS. 16A-26C are similar to those of FIG. 16A and FIG. The voltages and currents required by the embodiment (b) are almost the same.

An apparatus having an elongated first coil portion 331 and an elongated second coil portion 334 is shown in FIG. This device comprises a single magnetic member 33 adjacent both coil sections.
7. 28 to 30 show an embodiment different from the device of FIG.

In FIG. 28, the magnetic member 337A has a yoke 340 and arms 343 and 346. Each arm 343, 346 terminates in a pole portion 350.
The arm 346 is connected to the adjacent roll surface (57 in FIG. 28).
, And includes a position 353 and is perpendicular to a plane tangent to the roll surface. Position 353 is the portion of roll surface 57 closest to arm 346. The pole portion 350 of the arm 346 includes a location 353 and defines a surface 356 that is substantially parallel to a plane tangent to the roll surface 57. Yoke 340 and arm 34
0, 346 define grooves for receiving at least a portion of the coil portions 331, 334. The coil portion 334 and the pole portion 350 of the arm 346 generate a magnetic field that controls the shape of the meniscus 75. Coil part 331 and arm 3
The pole portion 350 of the 43 forms a magnetic field that attenuates the waves of the molten metal. As is clear from FIG.
1, 334 have a substantially circular cross section.

In FIG. 29, the magnetic member 337B has a yoke 370. The yoke 370 has a first magnetic pole portion 373 closest to the roll surface 57 and a second magnetic pole portion 376 remote from the roll surface 57. ing. Magnetic pole part 3
73 indicates that the magnetic pole portion 373 has the surface 3 as shown in FIG.
It is tapered to define 77. Surface 377 includes a location 380 on roll surface 57 and is substantially parallel to a plane tangent to roll surface 57. Position 380
Is the portion of the roll surface 57 closest to the pole portion 373. The pole portion 376 can be tapered, as shown in FIG. Coil part 334 and magnetic pole part 3
73 forms a magnetic field that controls the shape of the meniscus 75. The coil portion 331 and the pole portion 376 form a magnetic field that attenuates the molten metal wave. Coil parts 331, 33
4 has a substantially triangular cross section as shown in FIG.

In FIG. 30, a magnetic member 337C is a yoke 39 connecting the first arm 403 and the second arm 406.
It has 0. The first arm 403 is remote from the roll surface (57 in FIG. 30) and terminates in a pole portion 408. The second arm 406 is closest to the adjacent roll surface (57 in FIG. 30) and terminates in a pole portion 409. The pole portion 409 is tapered, and the pole portion 4
09 defines the surface 412. Surface 412 includes a region 415 of the adjacent roll surface and is substantially parallel to a plane tangent to the roll surface. Region 415 is the region of the adjacent roll surface closest to pole portion 409. The pole portion 408 is tapered. Coil part 3
31 and 334 are received between the arms 403 and 406 and have a rectangular cross section. The coil portion 334 and the pole portion 409 generate a magnetic field that controls the shape of the meniscus 75. The coil portion 331 and the pole portion 408 generate a magnetic field that attenuates the molten metal wave.

The magnetic members 337A to 337C contain the magnetic flux and reduce the necessary current. In contrast to the embodiments of FIGS. 11 (a) (b) and 12 with a leakage flux 98, there is no leakage flux in these embodiments.

The magnetic members 130 (FIG. 15) and 135 (FIG. 1)
6), 155 (FIG. 17), 167 (FIGS. 18 and 19),
186 (FIGS. 20 to 22 (b)), 227 and 220 (FIG.
3 and FIG. 24), 290A, 290B and 293 (FIG.
5 and FIG. 26) and 337 (FIGS. 27 to 30) are formed of a laminated body of ferromagnetic steel generally used as a magnetic member that functions at an audible frequency. Instead, the magnetic member 1
30, 135, 155, 186B, 227, 230, 2
90A, 290B and 293 can also be formed of tape windings of ferromagnetic steel. Further, the magnetic member can be formed of a suitable ferromagnetic steel having a relatively high permeability, such as ferrite.

The gap between the coil 82 and the magnetic member may be filled with a thermally conductive and electrically insulating material to prevent a short circuit between the coil and the magnetic member during operation. Such materials not only provide electrical insulation to the coil 82, but also make the water-cooled coil 82 a heat sink by transferring heat generated by eddy current losses in adjacent magnetic members to the water-cooled coil 82. . Alternatively, an air gap may be formed between the coil 82 and an adjacent magnetic member to prevent a short circuit between the magnetic member and the coil 82. Any suitable structure (not shown) may be used to retain air between the coil 82 for providing such a layer of air and the adjacent magnetic member. In this case, it does not function as a heat sink.

A refractory splash guard (not shown) similar to the splash guard 100 of FIG. 3 (b) surrounds the magnetic member and the coil. Such a splash guard performs a function similar to the function performed by the splash guard 100 described with respect to the apparatus of FIG. The splash guard conforms to the outer shape of each magnetic member and coil portion.

In the embodiment having the first coil portion and the second coil portion, and the first magnetic member and the second magnetic member as in the embodiment of FIGS. 24 to 26, the first splash guard (not shown) is used. One coil portion and the first magnetic member may be surrounded, and a second splash guard (not shown) may surround the second coil portion and the second magnetic member. Alternatively, in such an embodiment having a first coil portion and a second coil portion and a first magnetic member and a second magnetic member, the splash guard may surround all coil portions and each magnetic member. Can also.

Although the coil 82 has been described as a hollow body in the above embodiment, the conductor of the device 40 need not be hollow for water cooling. For example, as shown in FIG. 31, the device 40 comprises a wide loop coil consisting of a solid, conductive, narrow plate 450 having a curved cross section with a convex side facing the pool top surface 73. May have.
Side 456 of conductive plate 450 that places conductive tube 453 away from the adjacent roll surface (roll surface 57 in FIG. 31).
It can also be attached to In this embodiment, cooling water is supplied to the tubes 453 to remove heat from the plate 450.
Circulates inside. Plate 450, rather than tube 453,
Connected to a power source (not shown). The embodiment of FIG.
At 460, a magnetic field is generated.

The above detailed description is necessary only for understanding the present invention, and should not be construed as limiting.
Modifications and variations will be apparent to those skilled in the art.

[0105]

Since the present invention is constructed as described above, a low-cost electromagnetic meniscus control device and a control method for a continuously cast strip having good surface characteristics and a uniform thickness are provided. Can be provided.

[Brief description of the drawings]

FIG. 1 is a cutaway perspective view of a strip casting apparatus using one embodiment of the apparatus of the present invention.

FIG. 2 is a schematic circuit diagram of the device of FIG.

3 (a) is a side view showing a partial cross section of the casting apparatus of FIG. 1, and FIG. 3 (b) is a cross sectional view of a coil similar to the coil of FIG. 3 (a); Has a guard.

FIG. 4 (a) is an enlarged cutaway side view of a portion of the casting apparatus of FIG. 1 showing a partial cross section, wherein waves of the molten metal are affected by an electromagnetic force. FIG. 4B is a schematic diagram showing the direction of the electromagnetic repulsion of the electromagnetic field of FIG. 4A.

FIG. 5 is an enlarged cutaway side view of a portion of the casting apparatus showing waves of molten metal unaffected by electromagnetic forces.

FIG. 6 is a sectional view taken along line 6-6 of FIG. 3 (a), with a part removed.

7 is an enlarged cutaway side view of a portion of the casting apparatus of FIG. 1 showing a partial cross section, wherein the meniscus is affected by an electromagnetic force.

FIG. 8 is an enlarged cutaway side view of a portion of the casting apparatus showing a meniscus unaffected by electromagnetic force.

FIG. 9 is a cutaway perspective view of a strip casting apparatus using another embodiment of the apparatus of the present invention, showing a partial cross section.

FIGS. 10A and 10B are schematic circuit diagrams of the device of FIG. 9;

11 (a) is a cutaway side view of the casting apparatus of FIG. 9 in the absence of an electromagnetic field, showing a partial cross section, FIG.
(B) is a cutaway side view of the casting apparatus of FIG. 9 showing a partial cross-section, with the magnetic field shown at the same time.

FIG. 12 is a cutaway side view, partially in section, of a strip casting apparatus using yet another embodiment of the apparatus of the present invention, with the magnetic field shown.

FIG. 13 is a schematic configuration diagram of an apparatus of the present invention having a magnetic member.

14 (a) is a cutaway side view of a strip casting apparatus using one embodiment of the apparatus of FIG. 13, showing a partial cross section, and FIG. 14 (b) is a partial cross section. FIG. 14 is a cutaway side view of a strip casting apparatus using another embodiment of the thirteenth apparatus.

FIG. 15 is a cutaway side view of a strip casting apparatus using yet another embodiment of the apparatus of FIG. 13, showing a partial cross section.

FIG. 16 (a) is a schematic circuit diagram similar to FIG. 10 (b), and has a magnetic member. Fig. 16 (b) is a cutaway side view of a strip casting apparatus using one embodiment of the apparatus of Fig. 16 (a), showing a partial cross section.

FIG. 17 is a cutaway side view of a strip casting apparatus using another embodiment of the apparatus of FIG. 16 (a), showing a partial cross section.

FIG. 18 (a) shows a partial cross section, FIG.
FIG. 18 (b) is a cutaway side view of a strip casting apparatus using still another embodiment of the apparatus of FIG.
It is 18A-18B arrow sectional drawing of (a).

FIG. 19 is a cutaway side view of a strip casting apparatus using yet another embodiment of the apparatus of FIG. 16 (a), showing a partial cross section.

FIG. 20 is a schematic circuit diagram of another embodiment of the device of the present invention having a magnetic member.

21 is a cut-away side view of a strip casting apparatus using one embodiment of the apparatus of FIG. 20, showing a partial cross section.

FIG. 22 (a) is a cutaway side view of a strip casting apparatus using another embodiment of the apparatus of FIG. 20, showing a partial cross section, and FIG. 22 (b) is a cutaway side view of FIG. It is an exploded view of a magnetic member.

FIG. 23 is a schematic circuit diagram of still another embodiment of the device of the present invention having a magnetic member.

24 is a cut-away side view of a strip casting apparatus using one embodiment of the apparatus of FIG. 23, showing a partial cross section.

FIG. 25 is a cut away side view of a strip casting apparatus using another embodiment of the apparatus of FIG. 23, showing a partial cross section.

FIG. 26 is a cutaway side view of a strip casting apparatus using yet another embodiment of the apparatus of FIG. 23, showing a partial cross section.

FIG. 27 is a schematic circuit diagram of still another embodiment of the device of the present invention having a magnetic member.

FIG. 28 is a cutaway side view of a strip casting apparatus using one embodiment of the apparatus of FIG. 27, showing a partial cross section.

FIG. 29 is a cutaway side view of a strip casting apparatus using another embodiment of the apparatus of FIG. 27, showing a partial cross section.

30 is a cutaway side view of a strip casting apparatus using yet another embodiment of the apparatus of FIG. 27, showing a partial cross section.

FIG. 31 is a cutaway side view, partially in section, of a strip casting apparatus using one embodiment of the apparatus of the present invention using a plate to generate an electromagnetic field.

[Explanation of symbols]

 40 ... Electromagnetic meniscus control device 46 ... Continuous strip casting device 49 ... First roll 52 ... Second roll 57, 60 ... Roll surface 65 ... Pool 70 ... Nozzle 73 ... Pool top surface 75 ... Meniscus 79 ... Meniscus position 82 ... Coil 88 ... wave 97 ... coil part

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Walter F. Praeg United States 60440-1924 Illinois Bolingbrook Lakeview Circle 340 (72) Inventor Joseph G. Latchford United States 46410 Illinois Meri Ruville West 57th Place 2256 (72) Inventor You Shin Wan United States 60565 Illinois Nay Perville Fox River Lane 2752

Claims (66)

[Claims] 1. A continuous strip casting apparatus comprising a pair of counter-rotating rolls having mutually facing surfaces defining a space for holding a pool of molten metal having a top surface, wherein the pool top surfaces are interconnected. A meniscus is formed at each position in contact with the roll surface facing the
A device for magnetically controlling each of said meniscuses, said device having control means adjacent to said position and outside the roll at that position, said control means controlling the meniscus at that position An electromagnetic meniscus control device in continuous casting, having means for generating an electromagnetic field acting on the top surface of said pool adjacent to its location. 2. The continuous strip casting apparatus has a nozzle for supplying molten metal to the pool, and the pool top surface has a wave formed by the molten metal from the nozzle, and the wave is usually at the position. 2. The apparatus of claim 1 wherein said control means comprises means for generating an electromagnetic field that reduces the amplitude of a wave adjacent the meniscus. 3. The apparatus according to claim 1, wherein said pool top surface and said roll surface define said meniscus angle at said position, and said control means comprises means for generating an electromagnetic field for controlling said meniscus angle. . 4. The continuous strip casting apparatus has a nozzle for supplying molten metal to the pool, and the top of the pool has a wave formed by the molten metal from the nozzle, and the wave is generally at the position. 2. The apparatus of claim 1 wherein said control means comprises means for generating an electromagnetic field to move towards each of said waves and to form a barrier between said waves and a roll surface adjacent said position. 5. The apparatus according to claim 1, wherein said control means comprises a conductive coil, and said device comprises means for flowing a time-varying current through said coil to generate an electromagnetic field. apparatus 6. The apparatus of claim 5, wherein said coil comprises a wide loop coil. 7. The control device according to claim 1, wherein the control means has a magnetic member coupled to the wide loop coil, and the magnetic member has a current smaller than a current without the magnetic member. 7. The apparatus according to claim 6, further comprising means for forming the electromagnetic field so that the electromagnetic field can perform the function of (1). 8. The coil of claim 7 wherein said wide loop coil has a coil portion adjacent said meniscus location, and wherein a cross section of said coil portion has means cooperating with a magnetic member to form said electromagnetic field. apparatus. 9. The apparatus according to claim 7, wherein said magnetic member comprises a laminated body of ferromagnetic steel or a tape wound of ferromagnetic steel or ferrite. 10. The function according to claim 1, wherein the coil includes a coil portion adjacent to the position and does not include a magnetic member that affects the magnetic field. 6. Apparatus according to claim 5, including means for generating an electromagnetic field sufficiently close to said location so that a field can be fulfilled. 11. The coil according to claim 10, wherein said coil is a wide loop coil and said coil cross section has means for forming said field so that said field can perform said function.
The described device. 12. The apparatus of claim 10, wherein said coil has means for allowing said field to perform at least two of said functions. 13. The apparatus of claim 5, wherein said coil comprises a narrow loop coil. 14. The control device according to claim 1, wherein said control means has a magnetic member coupled to said narrow loop-shaped coil, and said magnetic member has a smaller current than a current without the magnetic member. 14. Apparatus according to claim 13, comprising means for forming said field so that said field can fulfill the stated function. 15. The magnetic member having means for forming the electromagnetic field such that the electromagnetic field can perform at least two of the functions with less current than without the magnetic member. 15. The apparatus according to 14. 16. A method according to claim 16, wherein the narrow loop-shaped coil is electrically connected to the first coil portion at the meniscus position via a gap between the first coil portion and the first coil portion. A second coil portion laid down on the first coil portion, wherein a cross section of the first coil portion has an electromagnetic field (a) controlling the meniscus, (b) controlling an angle of the meniscus, 15. The apparatus of claim 14, further comprising means for cooperating with the magnetic member to form an electromagnetic field to perform both (a) and (b). 17. The cross-section of the second coil, wherein the electromagnetic field reduces (c) the amplitude of the wave adjacent to the meniscus or (d) the barrier between the wave and the roll surface adjacent to the meniscus location. 17. Apparatus according to claim 16, comprising means cooperating with a magnetic member to form an electromagnetic field to form or perform both (c) and (d). 18. The apparatus according to claim 14, wherein said magnetic member comprises a laminated body of ferromagnetic steel or a tape wound of ferromagnetic steel or ferrite. 19. A second coil laid on the first coil portion with a gap between the first coil portion having the narrow loop-shaped coil laid on the meniscus and a gap between the first coil portion. 14. The apparatus of claim 13, comprising means for electrically connecting the first coil portion and the second coil portion. 20. The first coil portion and the second coil portion are substantially equidistant from the pool top surface.
The described device. 21. The first coil portion, wherein an electromagnetic field acts on a pool top surface adjacent to the location to control (a) the meniscus, (b) control an angle of the meniscus, or Means for generating an electromagnetic field so as to perform both (a) and (b), wherein the second coil portion is adapted to (c) reduce the amplitude of a wave adjacent to the meniscus position; Reduce (d) form a barrier between the wave and the roll surface adjacent to the meniscus location, or create an electromagnetic field to perform both (c) and (d) 20. The method according to claim 19, further comprising:
The described device. 22. A cross-section of the first coil portion wherein the electromagnetic field controls (a) the meniscus, or (b) the angle of the meniscus, or both (a) and (b). 22. The apparatus of claim 21, further comprising means for forming an electromagnetic field to perform 23. The cross-section of the second coil portion, wherein the electromagnetic field (c) reduces the amplitude of the wave or (d) forms a barrier between the wave and a roll surface adjacent the location. 23. The apparatus of claim 22, further comprising means for forming an electromagnetic field to perform both (c) and (d). 24. A vertically elongated first coil portion in which the narrow loop coil is adjacent to the position; a vertically elongated second coil portion electrically connected to the first coil portion; The device of claim 14, wherein the two-coil portion has a substantially triangular cross section. 25. The control means adjacent to the position,
Each of the arms has a first magnetic member having a pair of arms ending with a magnetic pole portion, a part of the coil is located between the pair of arms, and the first magnetic member has no magnetic member 6. The device according to claim 5, comprising means for forming an electromagnetic field so that the field can fulfill the function according to any of claims 1 to 4 with less current than in the case. 26. The coil according to claim 26, wherein the coil has a narrow loop-shaped coil including a first coil portion adjacent to the position and a second coil portion electrically connected to the first coil portion. 26. The apparatus of claim 25, wherein the member has a yoke, and wherein the yoke and the pair of arms define a groove for receiving at least a portion of the first and second coil portions. 27. The first magnetic member includes means for forming an electromagnetic field such that the electromagnetic field can perform at least two of the functions with less current than without the magnetic member. 26. The apparatus of claim 25. 28. The first magnetic member has a vertically elongated portion, the vertically elongated portion of the first magnetic member has a semicircular cross section, the coil portion received by the pair of arms has a vertically elongated portion, 3. The method according to claim 2, wherein the longitudinal portion of the coil portion has a circular cross section.
An apparatus according to claim 5. 29. The coil portion disposed between the pair of arms, wherein the first magnetic member has a yoke coupled to the pair of arms, each of the arms being substantially perpendicular to the yoke. Has a vertically elongated portion, and the vertically elongated portion of the coil portion has a rectangular cross section.
An apparatus according to claim 5. 30. The arm portion of the first magnetic member is branched from a connecting portion, the coil portion disposed between the pair of arms has a vertically long portion, and the vertically long portion has a rectangular cross section or a triangular shape. 26. The device of claim 25 having a cross section. 31. The coil according to claim 31, wherein the coil has a narrow loop-shaped coil including a vertically elongated first coil portion adjacent to the position and a vertically elongated second coil portion electrically connected to the first coil portion. The coil portion is a coil portion received between the pair of arms on the first magnetic member, wherein the first magnetic member has a yoke having first and second opposed ends, 26. The apparatus of claim 25, wherein one end and said pair of arms define a groove for receiving said first coil portion, and wherein said second coil portion is adjacent to a second end of said yoke outside said groove. 32. The coil according to claim 32, wherein the coil has a narrow loop-shaped coil including a vertically elongated first coil portion adjacent to the position and a vertically elongated second coil portion electrically connected to the first coil portion. 26. The apparatus of claim 25, wherein the arm of the member is substantially bifurcated from a connection, and wherein the first coil portion is a coil portion received between a pair of arms on the first magnetic member. 33. The apparatus of claim 32, wherein said first coil portion has a substantially triangular or rectangular cross section and said second coil member has a substantially circular cross section or a triangular shape. 34. One of said pair of arms is proximate to a mutually facing roll surface, the other of said one arm is remote from a proximate mutually facing roll surface, and said first coil portion is substantially 34. The apparatus of claim 33, wherein when having a triangular cross-section, said pole portions of said arms proximate roll surfaces facing each other are tapered. 35. The coil having a narrow loop coil, the control means having first and second magnetic members coupled to the narrow loop coil, wherein the magnetic member has no magnetic member. 6. The device according to claim 5, comprising means for forming an electromagnetic field so that the field can fulfill the function according to any of claims 1 to 4 with less current than in the case. 36. The magnetic member having means for forming an electromagnetic field such that the electromagnetic field can perform at least two of the functions with less current than without the magnetic member. Equipment. 37. The narrow loop-shaped coil is disposed laterally on the first coil portion via a gap between the vertically elongated first coil portion and the first coil member which are adjacent to the position and laid on the meniscus. A vertically elongated second coil portion, wherein the coil has means for electrically connecting the first coil portion and the second coil portion, the first magnetic member is adjacent to the meniscus position, The second magnetic member is disposed apart from the first magnetic member, and the first magnetic member has a current smaller than that in a case where the first magnetic member is not provided, and a top surface of the pool whose electromagnetic field is adjacent to the position. (A) controlling the meniscus, (b) controlling the angle of the meniscus, or performing both (a) and (b) to form the electromagnetic field. Means, the first coil Claim minute cross section having means for cooperating with said first magnetic member in order to form the electromagnetic field 35
The described device. 38. The second magnetic member, wherein the electromagnetic field reduces the amplitude of the wave adjacent to the meniscus with less current than without the second magnetic member, or (d) reduces the amplitude of the wave adjacent the meniscus. Means for forming the electromagnetic field so as to form a barrier between the roll surface adjacent to the meniscus or to perform both (c) and (d); 38. The section of a portion having means cooperating with said first magnetic member to form said electromagnetic field.
The described device. 39. The first narrow coil portion has a narrow loop-shaped coil which is laterally arranged on the first coil portion via a gap between the first elongated coil portion and the longitudinally elongated first coil portion adjacent to the position. Attached vertically elongated second coil portion, wherein the coil has means for electrically connecting the first coil portion and the second coil portion, wherein the first magnetic member is adjacent to the position and each arm An end has a pair of arms ending with a magnetic pole portion, at least a part of the first coil portion is received between the pair of arms on the first magnetic member, and the second magnetic member is the first magnetic member. Adjacent to a magnetic member, the second magnetic member has a pair of arms each end of which ends with a magnetic pole portion, and at least a part of the second coil portion is a pair of arms of the second magnetic member. Claim 35 to be accepted in the meantime On-board equipment. 40. The arm of each of the magnetic members branches off from a connecting portion, the first coil portion has a rectangular cross section, and a long side of the rectangle faces an adjacent roll surface; 40. The device of claim 39, wherein the two-coil portion has an annular or circular cross section. 41. An electromagnetic field acting on the top surface of the pool adjacent to the position with a current smaller than that without the first magnetic member, wherein the first magnetic member controls (a) the meniscus. Or (b) means for forming the electromagnetic field so as to control the angle of the meniscus, or to perform both (a) and (b), wherein the second magnetic member comprises: With a current smaller than the current without the second magnetic member, the electromagnetic field can (c) reduce the amplitude of the wave adjacent to the meniscus or (c) reduce the amplitude of the wave and the roll surface adjacent to the meniscus position. 4. Means for forming said field so as to form a barrier between them or to perform both (c) and (d).
An apparatus according to claim 9. 42. The control means includes a magnetic member having a pair of arms adjacent to the position and each arm terminating in a magnetic pole portion, the coils being electrically connected to one another and spaced apart from each other. A narrow loop coil having first and second coil portions, wherein one of the arms of the magnetic member is received by the first and second coil portions, wherein the magnetic member has no magnetic member. An apparatus according to claim 5, further comprising means for forming an electromagnetic field so that the electromagnetic field can perform the function according to any one of claims 1 to 4 with a current smaller than the current in (1). 43. The control means includes a magnetic member adjacent to the position and including a yoke, a first arm, a second arm, and a third arm, each arm extending from the yoke, and each arm being a magnetic pole portion. Wherein the second arm is disposed between the first arm and the third arm, and wherein the coil comprises first and second coil portions electrically connected to each other and spaced apart. A narrow loop-shaped coil including: at least a part of the first coil portion is located between the first arm and the second arm; and at least a portion of the second coil portion is the second The magnetic member is located between the arm and the third arm, and the magnetic member can perform the function according to any one of claims 1 to 4 with a current smaller than a current without the magnetic member. Forms the above electromagnetic field The apparatus of claim 5, further comprising means because. 44. The control means includes a magnetic member adjacent to the position and including a first arm, a second arm, and a third arm, each arm terminating in a magnetic pole portion, wherein the first arm is A longitudinal plane substantially co-planar with the third arm, wherein the second arm is substantially perpendicular to each of the first and third arms, and wherein the coils are electrically connected at a distance from each other; A narrow loop-shaped coil including first and second coil portions, at least a portion of the first coil is adjacent to the first and second arms, and at least a portion of the second coil is The magnetic member is adjacent to the second and third arms, and the magnetic member is capable of performing the function of claim 1 with a current smaller than the current without the magnetic member. Form an electromagnetic field Apparatus according to claim 5, comprising means for: 45. The first coil portion has a triangular cross section, and the second coil portion has a rectangular cross section.
The described device. 46. The control means includes a wide loop coil formed from a conductive plate having a curved cross section with a convex portion facing the pool top surface, wherein the device generates an electromagnetic field. 5. The apparatus according to claim 1, further comprising means for passing a time-varying current through the plate for the purpose. 47. Electromagnetically controlling a meniscus formed in a continuous strip casting apparatus having a pair of oppositely rotating rolls facing each other defining a space for holding a pool of molten metal having a top surface. Wherein the meniscus is formed at each location where the top surface of the pool contacts the roll surfaces facing each other, the method comprising: adjoining each location and outside the roll at that location. In continuous casting comprising means for generating an electromagnetic field, using said generating means to generate an electromagnetic field acting on the top surface of a pool adjacent to its location to control said meniscus Electromagnetic meniscus control method. 48. A nozzle for supplying molten metal to the pool, wherein the molten metal from the nozzle forms a wave on the top surface of the pool, and the wave generally moves toward the position, and forms a wave on the meniscus. 48. The method of claim 47, wherein the field is used to reduce the amplitude of adjacent waves. 49. The method of claim 47, wherein the pool top surface and the roll surface at the location define the meniscus angle and use an electromagnetic field to control the meniscus angle. 50. A nozzle for supplying molten metal into the pool, the molten metal from the nozzle forming a wave on the top surface of the pool, the wave generally moving toward the position, 48. The method of claim 47, wherein an electromagnetic field is used to create a barrier between the wave and the roll surface. 51. The method of claim 47, 48, 49 or 50, wherein a conductive coil is used to generate the electromagnetic field, and a time-varying current is passed through the coil to generate the electromagnetic field. 52. The method of claim 51, wherein said coil is a wide loop coil. 53. A wide loop coil is coupled to a magnetic member, and the electromagnetic field can perform the function according to any one of claims 47 to 50 with a current smaller than the current without the magnetic member. 53. The method of claim 52, wherein said magnetic member is used to form an electromagnetic field. 54. The method of claim 53, wherein the magnetic member is used to form the electromagnetic field such that the electromagnetic field can perform at least two of the functions with less current than without the magnetic member. The described method. 55. The function according to any one of claims 47 to 50, wherein a part of said coil is adjacent to said position and no magnetic member affecting the magnetic field is interposed. 52. The method of claim 51, wherein the electromagnetic field is generated sufficiently close to the location so that the field can be fulfilled. 56. The method of claim 55, wherein generating the electromagnetic field comprises generating the electromagnetic field sufficiently close to the location so that the electromagnetic field can perform at least two of the functions. Method. 57. The method of claim 51, wherein said coil is a narrow loop coil. 58. A magnetic member provided with said narrow loop-shaped coil, wherein said electromagnetic field is provided so that the electromagnetic field can perform the function according to any one of claims 47 to 50 with a smaller current than when no magnetic member is provided. 58. The method of claim 57, wherein said magnetic member is used to form a field. 59. The method of claim 58, wherein the magnetic member is used to form an electromagnetic field such that the electromagnetic field can perform at least two of the functions with less current than without the magnetic member. the method of. 60. A second coil portion lying on the first coil portion with a gap between the first coil portion lying on the meniscus and the first coil portion in the narrow loop coil. 58. The method of claim 57, comprising: 61. An electromagnetic field acting on the pool top surface adjacent to said location (a) controls said meniscus;
(B) using the first coil portion to generate the electromagnetic field to control the angle of the meniscus or to perform both (a) and (b); The electromagnetic field to reduce the amplitude of the wave adjacent to the meniscus, (d) form a barrier between the wave and the roll surface, or perform both (c) and (d) 61. The method of claim 60, wherein a second coil portion is used to generate the second coil portion. 62. A cross-sectional shape in which an electromagnetic field (a) controls the meniscus, (b) controls the angle of the meniscus, or performs both (a) and (b). 62. The method according to claim 61, comprising a coil portion. 63. The electromagnetic field (c) reduces the amplitude of the wave adjacent the meniscus, (d) forms a barrier between the wave and the roll surface, or (c) and (d). 63. The method of claim 62, wherein the second coil portion is provided with a cross-sectional shape that performs both of the following. 64. The method according to claim 47, wherein the coil is provided with a narrow loop-shaped coil, and the first and second magnetic members are coupled to the narrow loop-shaped coil, and the current is smaller than the current without the magnetic member. 52. The method of claim 51, wherein the magnetic member is used to form the electromagnetic field so that the electromagnetic field can perform the function of any of claims 50. 65. Use of the first and second magnetic members to form the electromagnetic field such that the electromagnetic field can perform at least two of the functions with less current than without the magnetic member. 65. The method of claim 64. 66. A narrow loop-shaped coil comprising: a first coil portion lying on the meniscus; and a second coil portion lying on the first coil portion with a gap between the first coil portion and the first coil portion. The electromagnetic field acting on the pool top surface adjacent to the location may be (a) controlling the meniscus, (b) controlling the angle of the meniscus, or controlling both (a) and (b). Using the first coil portion to generate the electromagnetic field, such that the electromagnetic force acting on the top surface of the pool adjacent to the location with less current than without the first magnetic member. The field to form the electromagnetic field such that the field controls (a) the meniscus, (b) controls the angle of the meniscus, or performs both (a) and (b). Electromagnetic field using one magnetic member (C) reduce the amplitude of the wave adjacent to the meniscus, (d) form a barrier between the wave and the roll surface, or perform both (c) and (d). Using the second coil portion to generate the electromagnetic field, wherein the electromagnetic field (c) reduces the amplitude of the wave adjacent to the meniscus with less current than without the second magnetic member. Or (d) forming the barrier between the wave and the roll surface, or performing the (c) and (d) both by forming the second magnetic member to form the electromagnetic field. 65. The method of claim 64 for use.