JP2000052006A - Equipment and method for continuous casting of metallic pieces - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a continuous casting equipment to cast metallic pieces under the application of rotating magnetic field with large magnetomotive force obtained at the same current density and high saturated flux density. SOLUTION: This continuous casting equipment is composed of a cylindrical mold 1 with both ends opened, a nozzle 2 to supply a molten steel 3 from one open end of the mold 1, a cooler 4 to cool the molten steel 3, an electromagnet to apply a rotating magnetic field to the molten steel 3 in the mold 1, and rotating rolls 10 to pull out a solidified shell 9 made as the molten steel 3 grows and a billet 11 made as the solidified shell 9 grows. A magnetic pole 7 is formed narrow in the tip portion and wide in the bottom portion, and an exciting coil 6 is wound so as to meet its shape and cover its surrounding. As a result, the distance between adjacent magnetic pole tip corners is prolonged and the exciting coil 6 can be wound across almost total length of the magnetic pole 7, thus making it possible to reduce leakage flux and at the same time to increase the magnetomotive force by increasing the molten steel penetration flux.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting apparatus and a continuous casting method for metal pieces, and more particularly to a continuous casting apparatus and a continuous casting method for metal pieces cast under the application of a rotating magnetic field by an electromagnet.

[0002]

2. Description of the Related Art Conventionally, in continuous casting of metal slabs, a continuous casting apparatus for obtaining high quality slabs by applying a rotating magnetic field to the molten metal using an electromagnet as an axis in the direction of the slab delivery. It has been known. Japanese Patent Application Laid-Open No. 9-29403 describes a typical example of such a continuous casting apparatus.

FIGS. 5 to 7 show an example of the configuration of a conventional continuous casting apparatus for metal pieces. FIG. 5 is a perspective view showing the external configuration, FIG. 6 is a horizontal sectional view, and FIG. 7 is a vertical sectional view. It is. The continuous casting apparatus for metal pieces includes a mold 1, a nozzle 2,
The cooling device 4 includes an electromagnet including a magnetic pole 7 ′ and an exciting coil 6 ′ provided on the yoke 5. The molten steel 3 supplied into the mold 1 via the nozzle 2 is cooled by the cooling device 4, and A solidified shell 9 is generated on the contact surface of the solid. The solidified shell 9 is guided downward by the two rotating rolls 10 while growing, and is continuously sent out as a billet 11.

The electromagnet includes a frame-shaped yoke 5 provided on the outer periphery of the mold 1, four magnetic poles 7 ′ disposed inside the yoke 5, and a coil 4 wound around the outer periphery of the magnetic pole 7 ′.
And two AC power supplies 8 are connected to the four exciting coils 6 '. This AC power supply 8
When an alternating current is supplied to the exciting coil 6 ′, a flux penetrating the molten steel 12 is generated between the magnetic poles facing each other, whereby a uniform rotating magnetic field is generated in the molten steel 3 with the direction of delivery of the steel slab 11 as an axis. I do.

The Lorentz force generated by the rotating magnetic field acts perpendicularly to the direction in which the steel slab 11 is sent out, so that the downward flow during injection, which is the flow in the direction in which the steel slab 11 is sent out, and the upward flow generated as a circulating flow. The flow rate can be reduced. Therefore, the solidified shell 9 caused by the downward flow
Is prevented, and inclusion of inclusions in the molten steel 3 caused by the upward flow is suppressed. Hereinafter, this effect is called an electromagnetic braking action.

The flow of the molten steel 3 is generated in the circumferential direction by the rotating magnetic field. As a result, the solidified shell of molten steel growing from the contact portion with the inner wall of the mold is crystallized equally, and the gas component contained in the molten steel 3 is diffused uniformly, so that the number of small holes on the surface of the steel slab 11 to be generated is reduced. I do. Hereinafter, this effect is called an electromagnetic stirring effect.

[0007] The greater the amount of magnetic flux penetrating the molten steel 12, the greater the effect of these electromagnetic braking and electromagnetic stirring functions.

On the other hand, in the electromagnet, the flux penetrating the molten steel 12
Is generated, a leakage flux 13 having a magnetic path between two adjacent magnetic poles is generated. In connection with this, such a conventional continuous casting apparatus has the following problems.

In a conventional continuous casting apparatus that performs casting under the application of a rotating magnetic field, the structure of an electromagnet for obtaining a rotating magnetic field is such that the width of a magnetic pole when viewed in a horizontal section (hereinafter, the width of a magnetic pole is Refers to the width of the magnetic pole when looking at the horizontal section),
It is uniform from the root portion (the end near the yoke 5 in FIG. 6) to the tip portion (the end near the mold 1 in FIG. 6). The exciting coil 6 'is wound around the magnetic pole base so that the exciting coils 6' wound on adjacent magnetic poles do not come into contact with each other. Therefore, there are the following problems.

(1) The distance connecting the magnetic pole tip angles of the adjacent magnetic poles 7 'is short, and the magnetic flux concentrates on the magnetic path in this portion to become the leakage magnetic flux 13 and the molten steel penetration magnetic flux 12 is small.

(2) When the value of the current supplied by the AC power supply 8 is increased, the magnetic flux density at the base of the magnetic pole tends to reach the upper limit value (saturated magnetic flux density), and the upper limit value of the magnetic flux density that can act on the molten steel 3 is increased. small.

(3) A large amount of leakage flux 13 from the tip of the magnetic pole not covered by the exciting coil 6 ′
2 and the area (coil cross-sectional area) around which the exciting coil 6 'is wound is narrow, and a large magnetomotive force cannot be obtained.

[0013]

As described above, the conventional continuous casting apparatus for casting a metal piece under the application of a rotating magnetic field by an electromagnet has a leakage flux and a saturated magnetic flux density. Due to the upper limit of the density, there is an upper limit to the magnetomotive force that can be obtained, and therefore, there is also an upper limit to the effects of electromagnetic stirring and electromagnetic braking that can act on the cast piece.

The present invention has been made to solve the above-mentioned problems, and the magnetomotive force obtained at the same current density is large.
It is another object of the present invention to provide a continuous casting apparatus and a continuous casting method for casting a metal piece under application of a rotating magnetic field having a high saturation magnetic flux density.

[0015]

According to the present invention, there is provided a continuous casting apparatus for casting metal pieces under the application of a rotating magnetic field by an electromagnet. The mold for solidification in the process of flowing in the direction and the four magnetic poles are arranged at positions where the axes of adjacent magnetic poles make an angle of 90 degrees on one horizontal plane so as to surround the casting object, between the facing magnetic poles An electromagnet for applying the rotating magnetic field, in which a magnetic flux penetrating the casting object is generated in a horizontal direction, wherein the four magnetic poles are formed so that the width of the tip portion is smaller than the width of the root portion. .

According to a second aspect of the present invention, there is provided a continuous casting apparatus for casting a metal piece under the application of a rotating magnetic field by an electromagnet. And a magnetic flux penetrating the casting object between the facing magnetic poles so that the axes of the adjacent magnetic poles form an angle of 90 degrees on one horizontal plane so that the four magnetic poles surround the casting object. And an electromagnet for applying the rotating magnetic field, which is generated in the horizontal direction. The four magnetic poles form a region having a uniform width at a root portion, and a width of a tip portion from the region having the uniform width. Is formed narrow.

According to a third aspect of the present invention, there is provided a continuous casting apparatus for a metal piece according to the first or second aspect, wherein the coil of the electromagnet has a whole magnetic pole adapted to the shape of the magnetic pole. It is characterized by being wound to cover.

According to a fourth aspect of the present invention, there is provided a continuous casting method for casting carbon steel using the continuous casting apparatus for a metal piece according to the third aspect. 1.6 to 5 m / min, the magnetic flux density of the magnetic field generated by the electromagnet at the center of the mold center magnetic pole is 0.2 to 0.3 T, and the frequency of the alternating current for generating the rotating magnetic field is 0.3 to 0.3 T It is characterized by casting under the condition of 1 Hz.

The continuous casting apparatus and the continuous casting method of a metal piece which performs casting under the application of a rotating magnetic field by the electromagnet of the present invention can reduce the leakage flux and at the same time increase the molten steel penetration flux, and at the same current density The resulting magnetomotive force can be increased.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a perspective view showing an external configuration of a continuous casting apparatus for metal pieces according to a first embodiment of the present invention, and FIG. 2 is a horizontal sectional view of the same.

The apparatus for continuously casting metal pieces according to the first embodiment includes a cylindrical mold 1 having both ends opened, a nozzle 2 for supplying molten steel 3 to the mold 1 from one side of the open end of the mold 1, 1 was installed to cover a part of
A cooling device 4 for cooling the molten steel 3 in the mold 1;
An electromagnet including a magnetic pole 7 and an exciting coil 6 provided on a yoke 5 for applying a rotating magnetic field to the molten steel 3 in the mold 1 is installed so as to cover a part of the cooling device 4, and the molten steel 3 grows. 2 for withdrawing a solidified shell 9 formed by the process and a billet 11 formed by growing the solidified shell 9 from the opposite open end of the mold 1 to which the molten steel 3 is supplied.
A base rotating roll 10 is provided.

The molten steel 3 supplied into the mold 1 via the nozzle 2 is cooled by a cooling device 4, and a solidified shell 9 is formed on a contact surface with the mold 1. This solidified shell 9
Is grown downward by the rotating roll 10 and continuously sent out as a billet 11. That is, the molten steel 3 grows from the outer edge toward the center in a direction perpendicular to the direction of delivery of the steel slab 11, as shown in FIG.
With respect to the direction in which the billet 11 is delivered, the farther from the nozzle 2 the farther the nozzle 11 is advanced.

The electromagnet has four magnetic poles 7 provided on the yoke 5 and four exciting coils 6 wound around the magnetic poles 7 and connected to an AC power supply 8. Magnetic pole 7
Is arranged at a position where the axes of adjacent magnetic poles form an angle of 90 degrees on one horizontal plane outside the mold 1.
In the electromagnet, the exciting coil 6 wound around the two facing magnetic poles 7 is wound in a direction to reinforce each other's magnetic flux, is connected to the same AC power supply 8, and has a phase difference of the magnetic flux created by the two facing magnetic poles 7. Is 0 degrees. The exciting coil 6 wound around the two adjacent magnetic poles 7 is connected to a separate AC power supply 8 to supply an alternating current with a phase difference of 90 degrees, and the position of the magnetic flux generated by the two adjacent magnetic poles 7 is changed. The phase difference is 90 degrees.

When an AC current flows through the exciting coil 6 by the AC power supply 8, a molten steel penetrating magnetic flux 12 is generated between the magnetic poles 7 facing each other via the magnetic poles 7 and the yoke 5, which are ferromagnetic substances. At this time, the phase difference between the two sets of molten steel penetrating magnetic fluxes 12 having a magnetic path between the two magnetic poles 7 facing each other is 90 degrees, and they interact with each other so that the direction in which the steel slab 11 is fed out into the molten steel 3. A uniform rotating magnetic field is generated.

What is important in the present embodiment is that the magnetic pole 7 of the electromagnet is used.
The width of the magnetic pole tip is narrow, the width of the magnetic pole root is wide, and the excitation coil 6 is wound so as to cover the periphery of the magnetic pole 7 in accordance with the shape of the magnetic pole 7.

By reducing the width of the tip of the magnetic pole 7, the distance between the adjacent magnetic pole tip angles becomes longer, and the leakage flux 13 can be reduced and the molten steel penetration flux 12 can be increased. This is explained from the following. The magnetic flux density Bg (T) at the center of the molten steel is the magnetic flux density Bg in the magnetic pole 7.
It is proportional to c (T) and is expressed by the following equation.

Bg = (P0 / (P0 + P1)) · Bc (1) where P0: Permeance of magnetic path through which molten steel penetration magnetic flux 12 passes (H) P1: Permeance of magnetic path through which leakage magnetic flux 13 passes (H) In the above equation (1), when the permeance P1 is reduced, the coefficient of the magnetic flux density Bc increases, and the magnetic flux density Bg at the center of the molten steel also increases. Therefore, if the cross-sectional area through which the magnetic flux passes is constant, the distance between the facing magnetic poles is reduced. The molten steel penetration magnetic flux 12 can be increased while being kept constant. In general, the permeance P (H) between two magnetic poles is represented by the following equation: P = μS / L (2) where μ: magnetic permeability (H / m) S: cross-sectional area of magnetic path (m ² ) L: Length of magnetic path (m) From equation (2), to reduce permeance P,
It can be seen that the magnetic path L should be lengthened. As shown in FIG. 2, by reducing the width of the magnetic pole tip and lengthening the magnetic path of the leakage magnetic flux 13, the permeance P <b> 1 decreases and the molten steel penetration magnetic flux 12 can be increased.

Further, by increasing the width of the root portion of the magnetic pole 7, the magnetic flux density at the root portion of the magnetic pole can be made hard to reach the upper limit value (saturated magnetic flux density). This is explained from the following.

Since the magnetic flux density Bc in the magnetic pole 7 has an upper limit (saturated magnetic flux density) depending on the material of the magnetic pole, the magnetic flux density Bg at the center of the molten steel also has an upper limit. Magnetic flux number Φ (Wb) in magnetic pole 7
Is represented by the following equation.

Φ = Bc · Sc (3) where Sc: magnetic pole cross-sectional area (m ² ) As shown in FIG. 2, by increasing the width of the magnetic pole root portion and enlarging the magnetic pole cross-sectional area Sc. , The upper limit of the number of magnetic fluxes Φ can be increased. As the number of magnetic fluxes Φ in the magnetic pole 7 increases, the number of magnetic fluxes acting on the molten steel portion can also be increased, so that the upper limit of the magnetic flux density at the center of the molten steel can be increased. As the magnetic flux density at the center of the molten steel increases, the electromagnetic stirring and the electromagnetic braking effect increase, so that the upper limit of the electromagnetic stirring and the electromagnetic braking effect that can act on the molten steel can be increased.

Further, according to the present invention, by narrowing the width of the tip portion of the magnetic pole 7 and widening the width of the root portion, the exciting coil 6 can be wound so as to cover the entire magnetic pole. By winding the exciting coil 6 so as to cover the entire magnetic pole, (a) the magnetic path of the leakage magnetic flux from the side surface of the magnetic pole can be cut off by the exciting coil 6, and the molten steel penetration magnetic flux 12 can be increased. For example, as shown in FIG. 2, when the exciting coil 6 covers the entire magnetic pole 7, the cross-sectional area of the magnetic path of the leakage magnetic flux 13 is reduced. When the cross-sectional area S of the magnetic path is reduced, the permeance P1 is reduced as can be seen from the equation (2), so that the molten steel penetration magnetic flux 12 can be increased.

(B) Further, the coils wound around the adjacent magnetic poles do not come into contact with each other, so that the coil cross-sectional area can be made wider than that of the conventional device, and a large magnetomotive force can be obtained.

As a specific example of the present embodiment, the solid line a in FIG. 4 indicates the yoke outer dimensions 720 (mm) × 720 (mm),
Distance between facing magnetic poles 270 (mm), mold size 1
Magnetic flux density Bc in the magnetic pole when 69 (mm) x 169 (mm), magnetic pole tip width 70 (mm), and magnetic pole base width 170 (mm)
Shows the calculated value of the molten steel center magnetic flux density Bg with respect to. Together, the outer dimensions of the yoke are 760 (mm) x 760 (mm), the distance between the facing magnetic poles is 210 (mm), and the dimension in the mold is 150
(Mm) x 150 (mm), magnetic pole width is equal at tip and root
The calculated value of the conventional device of 30 (mm) is also shown as a dotted line c. At this time, the frequency of the current flowing through the exciting coil 6 is 5 (Hz).

The slope of the straight line in FIG. 4 indicates the coefficient of the magnetic flux density Bc in the magnetic pole in the equation (1). As shown in FIG. 4, the coefficient of the magnetic flux density Bc in the magnetic pole in the equation (1) is about 0.
From about 12 to about 0.1 in the device according to the invention.
It can be seen that the size has increased to 21. It can also be seen that the upper limit value of the molten steel center magnetic flux density Bg determined by the saturation magnetic flux density of the magnetic pole 7 has increased from about 0.18 (T) to about 0.32 (T).

In the device according to the present invention, the exciting coil 6 is wound with a width of 75 mm so as to cover the entire magnetic pole 7, and the sectional area of the coil region is 9.0E-3 (mm ² ). On the other hand, in the conventional device described above, the exciting coil 6 is concentratedly wound with a width of 80 (mm) around a portion from the base of the magnetic pole 7 to 70 (mm), and the cross-sectional area of the coil region is 5.6E-
3 (mm ² ). That is, the device according to the present invention can increase the magnetomotive force obtained at the same current density by about 1.6 times as compared with the conventional device. For example, using a magnet device (magnetic pole height 400 mm) according to the present embodiment, the carbon steel casting speed is set at a magnetic flux density of 0.2 to 0.3 T at the center of the mold and a power supply frequency of 0.3 to 1 Hz. 1.6-
As a result of casting at 5 m / min, (1) When the distribution of the shell thickness in the mold, which is correlated with the electromagnetic braking action, is seen, the deviation from the average value of the shell thickness. What was 37% could be reduced to ± 19.6% by installing this device. (2) In addition, the equiaxed crystal ratio of the cross section of the cast piece, which has a correlation with the electromagnetic stirring effect, was 9.8% in the absence of the present apparatus, but is 45 to 50% by installing the present apparatus. It was able to be crystallized uniformly.

[Second Embodiment] FIG. 3 shows a horizontal sectional view of a second embodiment according to the present invention.

The continuous casting apparatus according to the second embodiment comprises a first
Similarly to the embodiment, a mold 1, a nozzle 2, a cooling device 4, and an electromagnet are provided, and molten steel 3 supplied into the mold 1 via the nozzle 2 is cooled by the cooling device 4, and a contact surface with the mold 1 is provided. A solidified shell 9 is generated. As the solidified shell 9 grows, it is guided downward by a rotating roll (not shown) to form a billet 11 and is continuously fed.

The electromagnet has a yoke 5 and four magnetic poles 7 as in the first embodiment, and two AC power supplies 8 are supplied to the exciting coil 6. At this time, a molten steel penetrating magnetic flux 12 is generated between the magnetic poles facing each other, and a uniform rotating magnetic field is generated in the molten steel 3 with the sending direction of the billet 11 as an axis. At the same time, a leakage flux 13 having a magnetic path between two adjacent magnetic poles is generated.

What is important in the present embodiment is that the magnetic pole 7 of the electromagnet is used.
And the shape of the exciting coil 6, the width of the tip of the magnetic pole is narrow, the width of the base of the magnetic pole is wide, and there is a portion near the base of the magnetic pole where the magnetic pole width is uniform. Then, the exciting coil 6 is wound so as to cover the periphery thereof in accordance with the shape of the magnetic pole. By reducing the width of the tip of the magnetic pole 7, the distance between adjacent magnetic pole tip angles becomes longer, and the leakage flux 13 can be reduced while the molten steel penetration flux 12 can be increased. This is explained from the following.

As in the first embodiment, in addition to making the width of the tip of the magnetic pole 7 narrow and widening the root, a coil having a uniform width near the root of the magnetic pole 7 is provided. The area can be widened, and a larger magnetomotive force can be obtained than in the first embodiment.

As a specific example of this embodiment, a broken line b in FIG.
The outer dimensions of the yoke are 870 (mm) x 870 (mm), the distance between facing magnetic poles is 270 (mm), and the dimension in the mold is 169.
(Mm) x 169 (mm), magnetic pole tip width 70 (mm), magnetic pole root width 170 (mm), magnetic pole magnetic flux density Bc relative to magnetic flux density Bc in the magnetic pole when the magnetic pole width uniform length is set to 75 (mm) Shows the calculated value of. At this time, the frequency of the current flowing through the exciting coil 6 is 5 (Hz). From the broken line b shown in FIG. 4, it can be seen that the coefficient of the magnetic flux density Bc in the magnetic pole in the equation (1) is about 0.18, and it is understood that the coefficient is larger than that of the conventional device as in the first embodiment.

In the present embodiment, the magnetomotive force obtained at the same current density can be increased by about 2.7 times as compared with the conventional device, and the magnetomotive force can be increased by about 1 times compared with the first embodiment. 0.7 times larger. The upper limit of the molten steel center magnetic flux density Bc is about 0.27T. In the device according to the above embodiment, the exciting coil 6 is wound with a width of 75 mm so as to cover the entire magnetic pole 7, and the sectional area of the coil region is 1 mm.
5E-3 (mm ² ).

[0044]

As described above, in the continuous casting apparatus for a metal piece according to the present invention, four magnetic poles are arranged in the electromagnet such that the axes of adjacent magnetic poles form an angle of 90 degrees so as to surround the casting object. As for the magnetic pole, the width of the tip part is narrow and the width of the root part is wide, so the distance between adjacent magnetic pole tip angles becomes longer, and it is possible to wind almost the entire length of the magnetic pole according to the magnetic pole shape Therefore, it is possible to reduce the leakage magnetic flux and at the same time increase the molten steel penetration magnetic flux, and it is possible to increase the magnetomotive force obtained at the same current density. Further, in addition to the width of the tip portion of the magnetic pole being narrow and the width of the root portion being widened, a greater magnetomotive force can be obtained by providing a portion having a uniform magnetic pole width near the root portion of the magnetic pole.

Further, by increasing the width of the root portion, the magnetic flux density of the root portion does not easily reach the saturation magnetic flux density.

As described above, by increasing the magnetomotive force of the electromagnet obtained at the same current density, the effects of the electromagnetic braking action and the electromagnetic stirring action obtained at the same current density can be improved. Further, since the magnetomotive force of the electromagnet obtained at the same current density increases and the upper limit of the magnetic flux density increases, the upper limits of the effects of the electromagnetic braking action and the electromagnetic stirring action increase.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external configuration of a continuous casting apparatus for metal pieces according to a first embodiment of the present invention.

FIG. 2 is a horizontal sectional view in the embodiment.

FIG. 3 is a horizontal sectional view according to a second embodiment of the present invention.

FIG. 4 is a diagram showing the relationship between the magnetic flux density in the magnetic pole and the magnetic flux density at the center of molten steel in the apparatus of the present invention and the conventional apparatus.

FIG. 5 is a perspective view showing the appearance of a conventional continuous casting apparatus for metal pieces.

FIG. 6 is a horizontal sectional view of a conventional continuous casting apparatus for metal pieces.

FIG. 7 is a vertical sectional view of a conventional continuous casting apparatus for metal pieces.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Nozzle 3 Molten steel 4 Cooling device 5 Yoke 6 Exciting coil 7 Magnetic pole 8 AC power supply 9 Solidification shell 10 Rotating roll 11 Steel bill

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Yoichiro Tsumura 4-22, Kannonshinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Inside the Hiroshima Research Laboratory, Mitsubishi Heavy Industries, Ltd. (72) Koichi Hirata 4-chome Kannonshinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture No. 6-22 Mitsubishi Heavy Industries, Ltd. Hiroshima Laboratory (72) Inventor Masahiro Kasai 4-22 Kanon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Works F-term (reference) 4E004 AA09

Claims (4)

[Claims] In a continuous casting apparatus for casting a metal piece under the application of a rotating magnetic field by an electromagnet, a mold for solidifying a casting object in a process of flowing the casting object in a vertical direction, and four magnetic poles surround the casting object. As described above, the axes of adjacent magnetic poles are arranged at a position forming an angle of 90 degrees on one horizontal plane, and a magnetic flux penetrating the casting object between the opposite magnetic poles is generated in the horizontal direction, for applying the rotating magnetic field. An electromagnet, wherein the four magnetic poles are formed so that the width of the tip portion is smaller than the width of the root portion. 2. A continuous casting apparatus for casting a metal piece under the application of a rotating magnetic field by an electromagnet, wherein a mold for solidifying a casting object in a process of flowing the casting object in a vertical direction, and four magnetic poles surround the casting object. As described above, the axes of adjacent magnetic poles are arranged at a position forming an angle of 90 degrees on one horizontal plane, and a magnetic flux penetrating the casting object between the opposite magnetic poles is generated in the horizontal direction, for applying the rotating magnetic field. An electromagnet; wherein the four magnetic poles form a region having a uniform width in a root portion and a width of a tip portion is formed to be narrower than the region having a uniform width. . 3. The continuous casting apparatus of a metal piece according to claim 1, wherein the coil of the electromagnet is wound so as to cover the entire magnetic pole according to the shape of the magnetic pole. Continuous casting equipment. 4. A continuous casting method for casting carbon steel using the continuous casting apparatus for metal pieces according to claim 3, wherein a casting speed is 1.6 to 5 m / min and a magnetic field generated by the electromagnet is molded. Continuous casting of a metal piece, wherein the magnetic flux density at the center of the central magnetic pole is 0.2 to 0.3 T, and the frequency of the alternating current for generating the rotating magnetic field is 0.3 to 1 Hz. Method.