JP3132987B2 - Method for continuous casting of metal pieces and electromagnetic brake device for continuous casting of metal pieces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously casting metal pieces and an electromagnetic brake device for continuous casting.

[0002]

2. Description of the Related Art FIGS. 9 and 10 show a conventional electromagnetic brake device for continuous casting of metal pieces. FIG. 9 is a perspective view thereof, and FIG. 10 is a sectional view taken along line XX of FIG. This apparatus is a so-called billet-type continuous casting apparatus, and is provided with a mold 1 which is arranged in a vertical direction and stores a molten metal (hereinafter referred to as “molten steel”) 3, a core 5 provided on the outer periphery thereof, and a direct current (DC). It comprises a DC electromagnet composed of a coil 12 and two rotating rolls 10 for pulling out a steel slab 9 obtained by cooling the molten steel 3. The DC electromagnet has two magnetic poles 7 facing each other, and can effectively apply a strong static magnetic field to the molten steel 3.

When the molten steel 3 is supplied from the nozzle 2 to the mold 1, the molten steel 3 solidifies on the outer peripheral surface of the mold 1, and a solidified shell (not shown) is generated. The solidified shell is guided downward while growing as the rotation / winding roll 10 rotates, and the billet 9 is continuously fed out.

At this time, a DC current is supplied from a DC power supply 13 to a DC electromagnet provided on the outer periphery of the mold to apply a DC magnetic field in a horizontal direction, thereby suppressing the flow of molten steel below. As a result, the growth of the solidified shell is promoted, and the billet 9
Can be sent at high speed. The conditions for applying a magnetic field in the continuous casting method using this apparatus are as follows: (1)
The magnetic flux density is 2000 to 4000 Gauss, (2) the excitation frequency is 0 Hz (DC), and (3) the phase difference of the excitation current is 0 degree.

FIGS. 11 and 12 show a conventional electromagnetic stirring device for continuous casting of metal pieces as a device having a similar structure. FIG. 11 is a perspective view of the same, and FIG. 12 is XII-XII of FIG.
FIG. This apparatus comprises a two-pole three-phase AC electromagnet and a molten steel 3 having a mold 1 which is arranged in a vertical direction and stores molten steel 3, and has six magnetic poles 7 formed from a core 5 and an exciting coil 6 provided on the outer periphery thereof. And two rotating rolls 10 for pulling out a steel slab 9 obtained by cooling.

In the apparatus shown in FIGS. 11 and 12, the billet 9 is continuously fed out, similarly to the apparatus shown in FIGS. 9 and 10. At this time, by supplying current from the three-phase power supply 15 to the AC electromagnet provided on the outer periphery of the mold 1,
A horizontal rotating magnetic field is applied to stir the molten steel. As a result, a homogeneous shell grows and high quality billet 9 can be sent out. The conditions for applying a magnetic field in the continuous casting method using this apparatus are as follows: (1) a magnetic flux density of 40;
It is about 0 to 800 Gauss (10000 Gauss = 1 stellar), (2) the excitation frequency is 4 to 10 Hz, and (3) the phase difference of the excitation current is 120 degrees.

As a further similar configuration, an AC / DC power supply device 16 for supplying AC current and DC current to an exciting coil is provided.
There is an agitating device which also serves as an electromagnetic brake for continuous casting of metal pieces provided with (see, for example, JP-A-6-304719). 13 and 14 show the device diagrams. FIG. 13 is a perspective view thereof, and FIG. 14 is a sectional view taken along the line XIV-XIV of FIG. In this case, when used as electromagnetic stirring, an alternating current is supplied from the power supply device 16 to the DC coil 12 to generate a rotating magnetic field in the horizontal direction and generate a stirring force in the molten steel 3. When used as an electromagnetic brake,
When a DC current is supplied from the power supply device 16 to the DC coil 12, a DC magnetic field is generated in a direction perpendicular to the flow to generate a braking force in the molten steel flow. The conditions for applying a magnetic field in the continuous casting method using this apparatus are as follows.
When used as an electromagnetic brake, (1) a magnetic flux density of 200
0 to 4000 Gauss, (2) excitation frequency 0 Hz (DC),
(3) The phase difference of the exciting current is 0 degree. When used as electromagnetic stirring, the magnetic flux density is (1) about 400 to 800 gauss, (2) the excitation frequency is 4 to 10 Hz, and (3) the phase difference of the excitation current is 90 degrees.

[0008]

In the conventional electromagnetic brake device for continuous casting of metal pieces (FIGS. 9 and 10), since molten steel does not flow in the circumferential direction, (1) from the contact portion with the mold wall. The columnar crystal grows, the equiaxed crystal ratio indicating the homogeneity of the crystal of the cast slab becomes small, and the carbon or silicon content becomes uneven in the thickness direction of the slab, and (2) There is a problem that local crystal growth is likely to occur and many small holes called pinholes are generated on the surface of the steel slab.

In the conventional electromagnetic stirrer for continuous casting of metal pieces (FIGS. 11 and 12), the magnetic flux in the central portion of molten steel is at most about 800 gauss, and interrupts a flow which is a force proportional to the magnetic flux density. Because the braking force is weak,
(1) Local flow erosion of the molten steel solidified shell is caused by the downward flow during injection, which is the flow of the molten steel 3 in the mold axial direction, and (2) the intermediate flow in the molten steel is caused by the upward flow generated as a circulating flow of the downward flow. Floating of the object occurred, and the quality of the billet was deteriorated.

Furthermore, in the conventional electromagnetic stirrer combined with an electromagnetic brake for continuous casting of metal pieces (FIGS. 13 and 14), it was possible to use them independently as an electromagnetic brake and as an electromagnetic stirrer. However, the electromagnetic brake and the electromagnetic stirring could not be operated at the same time.

[0011]

Means for Solving the Problems A continuous casting method for a metal piece according to the present invention for solving the above-mentioned problems is a method for continuously casting a metal piece using a cooling mold having a square cross section. A magnetic field having the following conditions (a) to (c) is applied to the lower position. (A) The magnetic flux density at the center of the cooling mold is 2250 gauss or more and 4150 gauss or less. (B) The excitation frequency is a frequency range represented by the following range.

(Equation 3) (C) Using an electromagnet having four magnetic poles made of a ferromagnetic material at a position below a nozzle for injecting molten steel and at a position outside the cooling mold, and further having an excitation coil arranged around the magnetic poles, This is a magnetic field generated by passing an alternating current having a current phase different by 180 ° with respect to a coil of a facing magnetic pole and an alternating current having a current phase differing by 90 ° with an adjacent magnetic pole.

In the above method for continuously casting metal pieces, a cooling mold having an inner size of 150 mm × 150 mm is used.
Further, a magnetic field having the following conditions (a) and (b) is applied. (A) The magnetic flux density at the center of the cooling mold is 2250 gauss or more and 2450 gauss or less. (B) The excitation frequency is in the range of 0.85 to 1.89 Hz.

On the other hand, the construction of the continuous casting apparatus for metal pieces of the present invention is an apparatus for continuously casting metal pieces using a cooling mold having a square cross section, and (a) a position below a nozzle for injecting molten steel. And four magnetic poles made of a ferromagnetic material are arranged outside the cooling mold, and an exciting coil is arranged on the outer circumference of the magnetic pole. (B) The current phase is 180 ° with respect to the coil of the opposing magnetic pole. (C) applying a different AC current having a current phase different by 90 ° to adjacent magnetic poles, and (c) a magnetic flux density at a center portion of the cooling mold of not less than 2250 gauss and not more than 4150 gauss;
(D) The excitation coil is energized by using a power source whose frequency inside the mold is within 0.284 m and the excitation frequency is expressed in the following range.

(Equation 4)

That is, in the present invention, (a) four magnetic poles made of a ferromagnetic material are arranged at a position below the nozzle for injecting molten steel and outside the cooling mold, and an excitation coil is arranged around the magnetic poles. And (b) an alternating current having a current phase different by 180 ° from the coil of the facing magnetic pole and an alternating current having a current phase different by 90 ° from the adjacent magnetic pole. The excitation coil is energized by using a power supply in a frequency range represented by the following range, and (d) the magnetic flux density at the center of the cooling mold is 22
By having a magnetomotive force and a distance between magnetic poles of 50 gauss or more and 4100 gauss or less, (1) it has the advantage of an electromagnetic brake that suppresses the emergence of inclusions while preventing uneven growth of molten steel crystals, (2) The crystal of the molten steel growing from the contact portion with the mold wall can be equiaxed,
It is another object of the present invention to provide an apparatus capable of improving the quality of a billet, which has the advantage of electromagnetic stirring, that is, the number of small holes on the surface of the billet can be reduced.

<Operation> Consider a state in which four magnetic poles made of a ferromagnetic material are arranged below the nozzle for injecting molten steel and outside the cooling mold, and an excitation coil is arranged around the magnetic poles. .

(A) First, by adopting a structure having four magnetic poles, the cross-sectional area of a magnetic pole per one pole is increased in the case of a mold having the same dimensions as compared with a conventional structure having six magnetic poles. You can do it. As a result, the number of magnetic fluxes acting on the mold can be increased.

(B) Secondly, when currents having a current phase different by 180 ° are applied to opposing magnetic poles, both magnetic poles are excited in opposite polarities, so that magnetic flux penetrates molten steel existing between the magnetic poles. Thus, a high magnetic flux density can be obtained for molten steel. Further, a uniform rotating magnetic field can be obtained by supplying a current having a current phase different by 90 ° to the adjacent magnetic poles. In particular, by employing a structure having four magnetic poles, a symmetric magnetic field can be formed with respect to a mold having a generally quadrangular prism shape as compared with a conventional structure having six magnetic poles.

(C) Third, by setting the magnetomotive force and the distance between the magnetic poles so that the magnetic flux density at the center of the cooling mold is not less than 2250 gauss and not more than 4150 gauss, the flow in the direction perpendicular to the magnetic flux is reduced. Necessary braking force can be generated. This is explained from the following.

First, the braking force F (N / m ³ ) is obtained by the following equation. F = σ · V · B ² (1) where V: flow velocity in the direction perpendicular to magnetic flux (m / s) B: magnetic flux density (T) σ: electric conductivity (1 / Ω · m)

From the above equation, it can be seen that the braking force is proportional to the square of the magnetic flux density, and that the higher the magnetic flux density, the greater the braking force. FIG. 5 shows a measurement result of the rate of deceleration ((V ₀ −V ₁ ) / V ₀ ) when the initial flow velocity V ₀ is reduced to V ₁ by this force. If the casting speed is 4 m / min in continuous casting without installing an electromagnetic brake, a good slab can be obtained, so the casting speed required from productivity is 5 m / mi.
If the rate of deceleration in the case of n or more is 0.2 or more, it is considered practically useful. When the magnetic flux density at the center of the cooling mold is 2250 gauss or more, a necessary braking force can be generated for the flow in the direction perpendicular to the magnetic flux.

Further, since a magnetic pole made of a ferromagnetic material is used to apply a magnetic flux into the mold, the magnetic flux density at the center of the cooling mold has an upper limit due to the magnetic flux density value at which the magnetic pole is saturated. When a magnetic flux is generated in the gap using two opposed rectangular magnetic poles, the magnetic flux density B _g (Gauss) of the gap is expressed by the following equation.

(Equation 5)

[0022] The permeance of the above formula are geometrically determined, if the mold dimensions 100～284Mm, factor B _c of the right side of the above equation is determined to approximately 0.25 to 0.39.
Usually, the saturation magnetic flux density of the ferromagnetic material used for the magnetic pole is 15
000 / √2 gauss (effective value), and the maximum value of the magnetic flux density at the center of the cooling mold obtained when the magnetic shielding by the mold can be ignored is 15000 / ０００2 ×
0.58 = 4150 gauss. In particular, it is desirable that the center of the cooling mold be 2250 gauss or more and 2450 gauss or less. This is explained from the following.

FIG. 6 shows the braking force and the required power with respect to the magnetic flux density. As the magnetic flux density increases, the power increases, but especially at high magnetic flux densities, the core tends to be magnetically saturated, so that the characteristic requires more power. The figure shows the braking force per unit power. This shows that the greater the value, the more efficient the braking. From FIG. 6, it can be seen that the smaller the magnetic flux density is, the more efficient the braking can be performed within the required magnetic flux density range. In addition, the magnetic flux density changes with the fluctuation of the power supply output, so it is preferable to allow a margin about 10% larger.

Therefore, by setting the magnetic flux density at the center of the cooling mold to be 2250 gauss or more and 2450 gauss or less, it is possible to efficiently generate a braking force required for a flow in a direction perpendicular to the magnetic flux.

(D) Fourth, by energizing the excitation coil using a power source whose excitation frequency is expressed by the formula (6) (described later), it is necessary and sufficient to make the molten steel crystal uniform. A high rotational flow rate (0.4 m / sec) is obtained. This is explained from the following.

First, FIG. 7 shows the measurement results of the equiaxed crystal ratio of the generated steel slab with respect to the rotational speed of the molten steel. 0.4 from Fig. 7
It can be seen that if a rotational flow rate of m / sec or more is generated, an equiaxed crystal ratio of 18% or more is obtained, and saturation is achieved at a flow rate of 0.5 m / sec or more. Therefore, it can be seen that there is a necessary and sufficient rotational flow rate (0.4 m / sec or more) for making the molten steel crystal uniform.

Next, a necessary and sufficient rotational flow rate (0.4 m / se
To obtain c), show that the proper excitation frequency range exists. The rotating flow velocity is determined by the electromagnetic force generated by the rotating magnetic field and the frictional force between the molten steel and the inner wall of the mold. The synchronous speed V _s (m / s) of the rotating magnetic field is obtained by the following equation. V _s = π · f · D (3) where f: frequency (Hz) D: mold size (m)

Accordingly, the molten steel receives an electromagnetic force in the same direction as the rotational direction of the magnetic field in accordance with the applied magnetic flux density. However, since slip actually exists, the rotational flow velocity is smaller than the value of the equation (2). Become. Actually, the above-mentioned proper magnetic flux density 225
FIG. 8 shows measured values of the rotational flow velocity with respect to the excitation frequency in the case of 0 Gauss. From FIG. 8, the characteristics of the rotation speed V _rot (m / s) with respect to the excitation frequency and the dimensions in the mold are as follows: (1)
As the excitation torque increases, the rotational torque increases.
The following empirical formula is given by taking into account the fact that the rotational radius increases with the increase in the rotational flow velocity and (2) the increase in the inner diameter of the mold. V _rot = (0.869 · f + 0.101) · D (4)

Here, when the magnetic flux density is higher than 2250 gauss, the flow velocity becomes larger than the value obtained by the equation (3). Therefore, the necessary and sufficient rotational flow rate is V
_{Assuming eff} , the condition required for the excitation frequency is as follows.

(Equation 6)

As a condition satisfying the expression (5), a frequency range represented by the following expression is obtained.

(Equation 7)

Therefore, by energizing the excitation coil using a power source having a frequency range in which the excitation frequency is expressed by the formula (6), a necessary and sufficient rotational flow rate (0. 4 m / sec).

In particular, the inner dimensions of the mold shown in FIG.
In the case of × 150 mm, an appropriate rotational flow velocity can be obtained by energizing the excitation coil using a power supply having an excitation frequency in the range of 0.85 to 1.89 Hz.

As described above, by generating a magnetic flux perpendicular to the mold axis at a position below the nozzle for injecting the molten steel and at a position outside the cooling mold, (1) the molten steel in the mold axial direction The flow velocity of the downward flow at the time of injection, which is the flow of the liquid, and the upward flow generated as its circulating flow can be reduced. For this reason, the local erosion of the molten steel solidified shell caused by the downward flow is suppressed, and the floating of the inclusions in the molten steel caused by the upward flow is suppressed. This effect is known as electromagnetic braking.

Further, by rotating the magnetic flux uniformly at a low frequency in the circumferential direction of the mold, (2) a molten steel flow is generated in the circumferential direction. This circumferential flow has the effect of stirring the molten steel. For this reason, since the crystal of the molten steel growing from the contact portion with the mold wall is formed at random, the crystal of the obtained molten steel becomes equiaxed and a molten steel having a uniform composition can be obtained. In addition, since the gas component contained in the molten steel is uniformly diffused by the stirring effect, the number of small holes generated on the surface of the generated steel slab is reduced.

By simultaneously having the effects of the electromagnetic brake and the electromagnetic stirring described above, the quality of the billet can be improved.

[0036]

Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto. 1 and 2 show a configuration example according to the present invention, FIG. 1 is an overall view, and FIG. 2 is a sectional view taken along the line II-II in FIG.

FIGS. 1 and 2 schematically show the apparatus according to the present embodiment. FIG. 1 is a perspective view and FIG. 2 is a sectional view taken along the line II-II of FIG. As shown in these drawings, the present apparatus is an apparatus for continuously casting metal pieces using a cooling mold (copper square tube) 1 having a square cross section, and includes the following (a) to (d).
Is provided. (A) Four cores 5 made of a ferromagnetic material are arranged at a position below the molten steel supply nozzle 2 for injecting the molten steel 3 and outside the cooling mold 1, and an exciting coil 6 is arranged around the core 5. are doing. (B) An AC current having a current phase different by 180 ° is applied to the coil of the opposing core 5 and an AC current having a current phase different by 90 ° is applied to an adjacent magnetic pole. (C) The magnetic flux density at the center of the cooling mold 1 is 225
The range is from 0 Gauss to 4150 Gauss. (D) The excitation coil is energized by using a power source whose cooling mold 1 has a dimension within 0.284 m and an excitation frequency in the following range.

(Equation 8)

In the above configuration, the core 5 has the magnetic poles 7 protruding from the respective end faces of the cooling mold 1, and the magnetic poles 7 are wound with the exciting coil 6, and the core 5 and the exciting coil 6 are integrated. Act as an electromagnet. In the device shown in FIGS. 1 and 2, the electromagnet has four magnetic poles. A cooling device (for example, a water-cooling jacket) 4 is disposed so as to surround the cooling mold 1, and a core 5 is disposed outside the cooling device 1 and below the nozzle 2.

In the above configuration, when an alternating current is supplied from the alternating current power supply 8 to the exciting coil 6, an alternating magnetic flux in the horizontal direction acts on the molten steel 3 so as to penetrate the mold 1.

Here, the phase difference between the currents flowing through the adjacent magnetic poles 7 is selected to be 90 °, and a current having a current phase different by 180 ° is supplied to the facing magnetic poles 7, thereby forming a shape penetrating the mold 1 and the molten steel 3. Thus, a high rotating magnetic flux density acts on the central portion of the molten steel.

When the horizontal rotating magnetic flux acts on the molten steel 3, (1) the flow velocity of the downward flow during injection, which is the flow of the molten steel in the mold axial direction, and the upward flow generated as a circulating flow thereof decrease. I do. In addition, (2) the molten steel flow is induced in the circumferential direction at the same time, and the stirring effect of the molten steel is brought about.

As a result, a non-uniform growth of the molten steel crystal is prevented, the floating of inclusions is suppressed, and a steel slab having a high equiaxed crystal ratio and few surface defects is obtained.

Also, such an electromagnetic brake device for continuous casting of metal pieces can change the positions of the four magnetic poles with respect to the mold surface so that the same device can cope with various dimensions of the mold 1. It becomes possible.

FIGS. 3 and 4 show examples of the configuration in this case.
3 is an overall view, FIG. 4A is a sectional view taken along the line IV-IV of FIG. 3, and FIG. 4B is a sectional view taken along the line IV-IV when four magnetic poles (integral with the coil) are removed. FIG. As shown in these drawings, the present apparatus has the same configuration as the apparatus for continuously casting metal pieces shown in FIGS. 1 and 2, except that four cores 5 made of a ferromagnetic material are provided with the cooling mold 1. Each of the magnetic poles 7 has an exciting coil 6 wound thereon, and the core 5 and the exciting coil 6 integrally function as an electromagnet. In the apparatus shown in FIGS. 3 and 4, the electromagnet has four magnetic poles. The movable magnetic pole 7 is provided with a core pressing plate 14, and by changing the fixing position of the core pressing plate 14 to change the positions of the four magnetic poles 7 with respect to the mold surface, the same The device is adapted to accommodate various mold 1 dimensions.

[0045]

As described above, according to the present invention, 1
In addition to the advantages of the electromagnetic brake that (1) preventing the non-uniform growth of molten steel crystals and suppressing the emergence of inclusions, (2) the crystal of molten steel that grows from the contact portion with the mold wall can be The advantage of electromagnetic agitation can be achieved at the same time, that is, axial crystallization can be performed and the number of small holes on the surface of the slab can be reduced, thereby improving the quality of the slab.

[Brief description of the drawings]

FIG. 1 is a configuration diagram according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II of FIG.

FIG. 3 is a configuration diagram according to a second embodiment of the present invention.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a diagram illustrating a measurement example of a deceleration rate with respect to a magnetic flux density according to the present invention.

FIG. 6 is a diagram of braking force and electric power (relative value) with respect to magnetic flux density according to the present invention.

FIG. 7 is a diagram of the equiaxed crystal ratio with respect to the rotational flow rate according to the present invention.

FIG. 8 is a diagram of a rotational flow velocity with respect to a frequency according to the present invention.

FIG. 9 is a view showing a configuration example of a conventional electromagnetic brake device for continuous casting of metal pieces.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

FIG. 11 is a view showing a configuration example of a conventional electromagnetic stirring apparatus for continuous casting of metal pieces.

12 is a sectional view taken along line XII-XII of FIG.

FIG. 13 is a view showing a configuration example of a conventional electromagnetic stirrer that also serves as an electromagnetic brake for continuous casting of metal pieces.

FIG. 14 is a sectional view taken along line XIV-XIV of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Molten steel supply nozzle 3 Molten steel 4 Cooling device 5 Core 6 Exciting coil 7 Magnetic pole 8 AC power supply 9 Steel piece 10 Rotating roll 11 Magnetic flux 12 DC coil 13 DC power supply 14 Core holding plate 15 3 phase power supply 16 AC / DC power supply

Continuation of the front page (72) Inventor Kazuya Tsuruzaki 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Research Laboratory (72) Inventor Hiroshi Nakajima 4-6-kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima 22 Hiroshima Research Institute, Mitsubishi Heavy Industries, Ltd. 4-6-22 Mitsubishi Heavy Industries, Ltd. Hiroshima Works (56) References JP-A-6-304719 (JP, A) JP-A-60-118359 (JP, A) JP-A-59-159256 (JP, A) JP-A-62-130752 (JP, A) JP-A-59-1056 (JP, A) JP-A-56-139264 (JP, A) JP-A-58-50157 (JP, A) JP-A-8-108 309494 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B22D 11/11 B22D 11/04 311 B22D 11/115 B22D 11/18

Claims (3)

(57) [Claims] 1. A method of continuously casting a metal piece using a cooling mold having a square cross section, wherein a magnetic field having the following conditions is applied to a position below a nozzle for injecting molten steel. Continuous casting method. (A) The magnetic flux density at the center of the cooling mold is 2250 gauss or more and 4150 gauss or less. (B) The excitation frequency is a frequency range represented by the following range. (Equation 1) (C) Using an electromagnet having four magnetic poles made of a ferromagnetic material at a position below a nozzle for injecting molten steel and at a position outside the cooling mold, and further having an excitation coil arranged around the magnetic poles, This is a magnetic field generated by passing an alternating current having a current phase different by 180 ° with respect to a coil of a facing magnetic pole and an alternating current having a current phase differing by 90 ° with an adjacent magnetic pole. 2. The casting method according to claim 1, wherein a cooling mold having an inner size of 150 mm × 150 mm is used.
A method for continuously casting metal pieces, wherein a magnetic field having the following conditions is applied. (A) The magnetic flux density at the center of the cooling mold is 2250 gauss or more and 2450 gauss or less. (B) The excitation frequency is in the range of 0.85 to 1.89 Hz. 3. An apparatus for continuously casting a metal piece using a cooling mold having a square cross section, comprising: (a) four ferromagnetic materials at a position below a nozzle for injecting molten steel and outside a cooling mold; A magnetic pole is arranged, and an exciting coil is arranged on the outer periphery of the magnetic pole. (B) The current phase is 1 with respect to the coil of the opposite magnetic pole.
An AC current having a difference of 80 ° and an AC current having a current phase differing by 90 ° with respect to adjacent magnetic poles are applied. (C) The magnetic flux density at the center of the cooling mold is 2250.
(D) a metal piece having a size within a mold of 0.284 m or less and a current supplied to an exciting coil using a power source having a frequency range represented by the following range: Electromagnetic brake device for continuous casting. (Equation 2)