JP2002028761A - Electromagnetic stirring method in mold for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic stirring method which can produce a cast slab effectively reducing non-metallic inclusion defect on the surface layer part by suitably controlling molten steel flow in a mold for continuous casting. SOLUTION: The molten steel near the long side mold walls is accelerated in the horizontal direction and mutually reverse directions with one pair of linear motors arranged at respective long sides of the mold and also, when the difference of meniscus heights of the molten steel near both sides of short side mold walls becomes not lower than a setting value, these linear motors are operated so that the stirring force of the linear motor accelerating the molten steel toward the short side wall at the lower side of the meniscus from the short side wall at the heigh side of the meniscus becomes larger than the stirring force of the other side of the linear motor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the flow of molten steel in a mold in a continuous casting of steel slabs by controlling the flow by applying electromagnetic force to the molten steel. The present invention relates to an electromagnetic stirring method capable of reducing defects.

[0002]

2. Description of the Related Art In continuous casting of a steel slab, a moving magnetic field type electromagnetic stirring coil (hereinafter referred to as a "linear motor") for generating an electromagnetic stirring force along a mold having a rectangular cross section is installed and moved to molten steel. By applying a magnetic field to form a swirling agitated flow in the molten steel near the meniscus, a technique was developed to prevent inclusions and bubbles from adhering to the solidified shell and produce a slab with few defects in the surface layer. I have.

FIG. 1 is a schematic explanatory view showing a state of molten steel flow in a mold in conventional slab continuous casting, and FIG. 2 is a sectional view taken along the line AA of FIG. As shown in FIGS. 1 and 2, in this continuous casting machine, a pair of linear motors is provided along the long side of the mold. Then, the molten steel flow discharged into the mold is stirred while being accelerated by these linear motors. In the configuration shown in FIGS. 1 and 2, the molten steel in the vicinity of the mold wall is accelerated horizontally and in opposite directions by a pair of linear motors.

[0004] However, in the conventional operation using the above-mentioned continuous casting machine, the following various problems have been pointed out. First, in slab continuous casting for producing semi-finished products for steel plates, the cross section of the slab is a rectangle with a large aspect ratio as shown in the figure, so compared to continuous casting of blooms and billets for wires and bars with an aspect ratio close to 1. However, there is a problem that the stirring efficiency when swirling and stirring the molten steel horizontally is deteriorated.

Further, as shown in FIG. 2, when the upward reversal flow of the discharge flow from the immersion nozzle collides with the electromagnetic stirring flow, there is a problem that the flow velocity decreases in the meniscus and a region where stagnation easily occurs is generated. When such a stagnation region occurs, inclusions and air bubbles adhere to the solidified shell in the region, and a surface defect occurs in the steel product. Alternatively, in the above-described configuration, a region where the stirring flow velocity is excessive may occur (for example, a region where the stirring direction by the linear motor and the direction of the reverse flow overlap), but if such a region occurs. As a result, the powder sprinkled on the surface of the meniscus is entangled in the molten steel, and a defect resulting from the powder-based inclusions occurs in the steel product.

For the purpose of reducing the interference between the discharge flow from the immersion nozzle and the electromagnetic stirring flow by the linear motor, for example, a technique as disclosed in Japanese Patent Laid-Open No. 7-9098 has been proposed. In this technique, as shown in FIG. 3, the discharge hole of the immersion nozzle is straight downward and the molten steel from the immersion nozzle is discharged downward, so that the discharge flow from the immersion nozzle and the electromagnetic stirring flow by the linear motor Is to reduce interference.

In such a technique, the interference between the discharge flow and the stirring flow is eliminated, but the effect of stirring the meniscus by the discharge flow is hardly exhibited. Therefore, when electromagnetic stirring cannot be applied for some reason, continuous casting itself becomes difficult. Would.

In the technique disclosed in Japanese Patent Application Laid-Open No. 7-9098, as shown in FIG. 3, the lower end position of the operation area (electromagnetic stirring area) by the linear motor is located lower than the lower end of the discharge hole of the immersion nozzle. Although the configuration is such that the kinetic energy of the discharge flow is not effectively used for agitation, there is a problem that the agitation efficiency is deteriorated.

On the other hand, in the prior art shown in FIGS. 1 and 2, the discharge hole of the immersion nozzle is biased toward molten steel in the mold due to clogging with alumina or the like.
). It has been pointed out that when such a drift occurs, the uniformity of the stirring deteriorates and the stirring efficiency decreases.

[0010] From the viewpoint of suppressing the above-mentioned drift in the mold, for example, a technique as disclosed in Japanese Patent No. 2965438 has been proposed. In this technique, the coil of the linear motor is divided into two in each direction of the long side of the mold (that is, a total of four coils are arranged), and each coil is divided based on the observation result of the flow state of the molten metal on the meniscus surface in the mold. It controls the stirring force. In this technique, for example, when the flow velocity from the short side on the left side (refer to FIGS. 1 and 2) to the immersion nozzle is low at the meniscus, control is performed so as to further increase the stirring force of the linear motor that accelerates the molten steel to the right. [Fig. 6 below]
(D)].

In this technique, the positional relationship between the immersion nozzle and the linear motor has not been clarified. However, as described above, there is a problem that the control method does not exert its effect due to this positional relationship. That is, in the above technique, when the linear motor is arranged such that the lower end position of the electromagnetic stirring area (see FIG. 3) by the linear motor is lower than the lower end of the immersion nozzle discharge hole, Control has the opposite effect on suppressing drift.

Also, in this technique, a skilled person needs to constantly monitor the molten metal flow state on the meniscus surface in the mold by directly observing it. Alternatively, even when connected to a sensor that outputs image processing results and the like, such as a television camera, advanced image processing technology is required, and it becomes difficult to perform quantitative control.

Further, in the above-mentioned technique, since the coil of the linear motor is divided into two in each direction of the long side of the mold, connection for supplying power to such a coil is complicated, and maintenance is deteriorated. There is a problem.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to appropriately control the flow of molten steel in a casting mold in continuous casting so that the non-surface portion of the casting is controlled. It is an object of the present invention to provide an electromagnetic stirring method capable of producing a cast piece in which metal inclusion defects are effectively reduced.

[0015]

Means for Solving the Problems The electromagnetic stirring method of the present invention, which has solved the above-mentioned problems, comprises: a dipping nozzle installed at the center of a continuous casting machine for producing a slab having a rectangular cross section;
In a method in which the molten steel flow discharged into both sides of the mold is electromagnetically stirred while being accelerated by a linear motor, a long side mold is provided by a pair of linear motors provided along each of the long sides of the mold. When the molten steel in the vicinity of the wall is accelerated in the horizontal direction and in the opposite direction to each other, and when the difference in the height of the molten steel meniscus in the vicinity of the short side mold wall on both sides exceeds a set value, the short side on the higher side of the meniscus It has a gist in controlling the stirring force of the linear motor that accelerates the molten steel from the side toward the short side of the lower side of the meniscus so as to be greater than the stirring force of the other linear motor to operate. .

In the above-described electromagnetic stirring method, the operating upper end positions of the two linear motors are set at ±± the reference meniscus height in the mold.
It is preferable that the linear motor be operated within a range of 50 mm and the lower end positions of both linear motors are arranged below the lower end of the discharge hole of the immersion nozzle.

Further, as a specific control mode of the linear motor in the above method, the height of the molten steel meniscus near the short side mold wall on both sides is measured, and based on the measurement result, the current value or frequency of both linear motors is measured. , The stirring force of each linear motor is controlled.

In the method of the present invention, when the difference between the average values of the heights of the meniscus of molten steel in the vicinity of the mold walls on both short sides becomes 15 mm or more, different stirring forces are generated in the pair of linear motors. Is particularly effective.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have studied from various angles the most effective control method of electromagnetic stirring flow in order to solve the above-mentioned problems in the prior art. As a result, the molten steel in the vicinity of the long side mold wall is moved in a horizontal direction by a pair of linear motors provided along the long side of the mold, basically using an apparatus having a configuration as shown in FIGS. And while accelerating in the opposite direction to each other, when the difference in the height of the molten steel meniscus in the vicinity of the short side mold wall on both sides is greater than or equal to the set value,
The operation is controlled by controlling the stirring force of the linear motor that accelerates the molten steel from the short side of the high meniscus side to the short side of the low meniscus side to be greater than the stirring force of the other linear motor. Then, the present inventors have found that the above-mentioned object can be achieved splendidly, and have completed the present invention.

That is, the present inventor has made repeated studies based on numerical calculations and the like. As a result, when the stirring area includes the entire reverse flow area near the meniscus and the entire area of the discharge flow, as a countermeasure against drifting, It was found that the control for increasing the stirring force for accelerating the molten steel in the direction of the discharge flow having the lower horizontal component was effective.

FIG. 4 is a schematic explanatory view showing an example of the configuration of an apparatus for carrying out the method of the present invention. In this apparatus, a level gauge is installed above each of the short side mold walls on both sides, and the height of the molten steel meniscus in the vicinity of the short side mold walls on both sides is measured by the level gauge. Have been. This level gauge can be constituted by, for example, an eddy current sensor. However, the same applies when a plurality of temperature sensors are buried in the height direction in the short side mold walls (for example, a copper plate) on both sides. The effect of can be exhibited. Furthermore, a level gauge using radiation or a level gauge using a laser beam can also be employed.

The signal obtained by measuring the height of the molten steel meniscus by the above level gauge is input as an input current (current command) to each linear motor through a time averaging process and a subtraction process. (Current value) according to the output, and the output controls the stirring force of each linear motor for accelerating the molten steel. In FIG. 4,
For convenience of explanation, the upper linear motor in the plan view
Side, and the lower linear motor is referred to as “− side”. Further, in the above configuration, the configuration is described in which the stirring force of each linear motor is controlled by changing the current value. However, the stirring force of the linear motors may be controlled by changing the frequency of both linear motors.

In the method of the present invention, as shown in FIG. 4, since molten steel is discharged from the immersion nozzle toward the short side mold walls on both sides, even if electromagnetic stirring cannot be applied for some reason, However, casting itself does not become difficult. In addition, from the viewpoint of minimizing interference between the discharge flow from the immersion nozzle and the electromagnetic stirring flow by the linear motor, the discharge angle of the immersion nozzle is preferably about 30 to 45 degrees downward with respect to the horizontal. .

Further, in the present invention, since a configuration is adopted in which the molten steel meniscus height in the mold is measured by two level gauges, the difference in the molten steel meniscus height in the vicinity of the short side mold on both sides is determined. Can be detected. In addition, automatic control becomes possible by registering in the process computer how to correct each current value (or frequency) of the two linear motors according to the height of the meniscus. Further, since the method of the present invention is carried out in an apparatus in which one linear motor is arranged for one long-sided mold, the apparatus configuration is relatively simple, and the maintainability is good.

The control procedure in the method of the present invention will be described with reference to FIG. In FIG. 5, due to the occurrence of drift, the molten steel meniscus height in the vicinity of the right side short side mold wall is increased.
This shows a state where the height is higher than the molten steel meniscus height near the left side short side mold wall. Such a state occurs when the leftward flow is fast at the molten steel flow velocity near the meniscus [FIG. 6 (a)] and the rightward flow is fast at the molten steel flow velocity near the discharge port lower end [FIG. 6 (b)]. .

In such a situation, according to the present invention, as shown in FIG. 6C, the stirring force of the linear motor for accelerating the molten steel from the right side where the meniscus is high to the short side of the left side where the meniscus is low is used. The control is performed so as to be larger than the stirring force of the other linear motor (see FIG. 4). By performing such control, even when a drift occurs and the meniscus height fluctuates, the fluctuation can be suppressed as much as possible and a uniform electromagnetic stirring force can be applied to the molten steel.

On the other hand, in contrast to the conventional technology (Japanese Patent No. 29
No. 65438) performs control to increase the rightward stirring force as shown in FIG. 6A and FIG. 6D based on the molten steel flow velocity near the meniscus. Control has the opposite effect on suppressing drift.

Next, in the continuous casting machine for carrying out the method of the present invention, an appropriate installation position of the linear motor will be described. First, the operating upper end position (the upper end of the electromagnetic stirring area) of both linear motors is set to ± the reference meniscus height in the mold.
It is preferable to be within the range of 50 mm. If the operating upper end position of the linear motor is too high, the electromagnetic stirring force cannot effectively act on the molten steel, and the power efficiency will be reduced. Further, when the upper end position of the operation is too low, the hindrance of stirring by the reverse flow becomes remarkable. Note that the operating upper end position and the operating lower end position of the linear motor are, for example, the upper end position and the lower end position of the core of the linear motor, respectively. The “reference meniscus height” means a target meniscus height during operation. For example, when the automatic control of the injection flow rate is performed by feeding back the output of one vortex level gauge, the meniscus height at the installation position of the vortex level gauge is used.

On the other hand, it is preferable that the lower end positions of operation of the two linear motors (the lower end of the electromagnetic stirring area) be lower than the lower end of the discharge hole of the immersion nozzle. That is, if the upper end position of the operation of the linear motor is set to be higher than the lower end of the discharge hole of the immersion nozzle, FIG. 7 (FIG. 7B is a cross-sectional view taken along the line CC in FIG. 8A). As described above, even if the molten steel is discharged along the long side (discharge flow), the discharge flow is drawn to the vicinity of the long side where the flow velocity is high, and turns in the stirring direction, so that the stirring efficiency is improved.

On the other hand, if the upper end position of the operation of the linear motor is above the lower end of the discharge hole of the immersion nozzle, FIG.
As shown in [FIG. 8 (b) is a cross-sectional view taken along line BB of FIG. 8 (a)], the molten steel (discharge flow) discharged from the immersion nozzle is:
Under the action of the electromagnetic stirring, it flows straight to both short sides.

According to the present invention, when the difference in the height of the molten steel meniscus in the vicinity of the mold wall on both sides of the short side becomes equal to or larger than the set value, the meniscus is shifted from the short side on the high side to the short side on the low meniscus side. The stirring force of the linear motor that accelerates the molten steel toward
The operation is controlled so as to be larger than the stirring force of the other linear motor, and the set value can be arbitrarily determined, but preferably, the average value of the average value of the molten steel meniscus height near the short side mold wall on both sides is preferable. It is particularly effective to generate a different stirring force for each linear motor when the difference is 15 mm or more.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following Examples are not intended to limit the present invention, and any design changes based on the gist of the preceding and following aspects will be described. It is included in the technical range of.

[0033]

EXAMPLE 1 An apparatus having the structure shown in FIG. 4 was used, and as shown in FIG.
When a difference between the heights of the meniscuses near the left and right short side molds is 15 mm or more, a setting for making a difference between the current values of the two linear motors is registered in a process computer in advance, and the current of the electromagnetic stirring is set by the process computer. Casting was performed to automatically control the values (hereinafter, such control is referred to as “drift control”).

At this time, as a comparative example, two linear motors were always set to have the same current value, and casting without performing drift control was also performed. Then, the occurrence time rate of the drift where the difference in the average value of the meniscus height for 30 seconds was 30 mm or more and the incidence rate of the thin plate surface defect caused by inclusions on the surface layer of the slab were investigated. The casting conditions at this time are as follows.

(Casting conditions) Steel type: carbon steel (C content: 0.003 to 0.18%) Mold width: 900 to 1600 mm Mold thickness: 240 mm Casting speed: 1.4 to 2.0 m / min Meniscus position: Mold upper end -70mm-Mold lower end -13
0mm Iron core upper end position: Mold upper end -100mm Iron core lower position: Mold upper end -400mm Immersion nozzle lower end position: Mold upper end -350mm Immersion nozzle discharge hole angle: Downward 35 ° Meniscus height average processing time: 30 seconds

FIG. 10 is a graph showing the effect of the presence / absence of the drift control on the drift occurrence time rate. In the case of Embodiment 1 in which the drift control is performed, the drift occurrence time rate is reduced to about 30%. You can see that. FIG. 11 is a graph showing the effect of the presence / absence of the drift control on the occurrence rate of sheet surface defects. In the case of Example 1 in which the drift control was performed, the incidence rate of sheet surface defects was reduced to about 70%. You can see that it is doing.

Example 2 The effect of controlling the stirring force in the case where a blockage deviated left and right was generated in the immersion nozzle was examined based on the flow calculation. The calculation conditions at this time are as follows. (Calculation conditions) Mold size: 1500 mm x 240 mm Casting speed: 1.8 m / min Electromagnetic stirring area: range from meniscus to 300 mm below meniscus Dip nozzle lower end: 250 mm below meniscus Dip nozzle shape: Discharge nozzle lower end angle is horizontal on both sides On the other hand, a drift is generated when the inside of the downward 35 ° nozzle is asymmetrically closed.

First, under the above conditions, the flow velocity distribution (vector distribution) at the center cross section of the mold thickness in the state where power is not supplied to either of the two linear motors and electromagnetic stirring is not performed is shown in FIG.
Shown in As can be seen from FIG. 12, the jet discharge angle from the discharge hole on the left side is smaller, and the reverse flow from the short side of the mold to the immersion nozzle near the meniscus is faster on the left side. In such a situation, the meniscus height on the left side becomes higher, so that the occurrence of drift can be detected by measuring the difference in meniscus height.

Based on the above calculation, the lower meniscus 5
0, 100, 150, 200, 250, 300 (mm)
The calculation result of the component of the flow velocity at the depth of
As shown in FIGS. FIG. 13 shows that the molten steel is oriented rightward (+
8) from the long side wall (shown as “wide surface” in the figure)
14 shows the result at a position 8 mm from the long side wall that accelerates the molten steel to the left (− side), and FIG. 15 shows the result at the nozzle center. FIG.

FIGS. 16 to 19 show the calculation results of the component of the flow velocity in the longitudinal direction of the mold when electromagnetic stirring is performed under various conditions with the immersion nozzle having the same closed state. At this time, each condition in FIGS. 16 to 19 is as shown below,
The meanings of the legends in the figure are as follows.

(Depth from meniscus) (Long side mold near the flow velocity display line) FIG. 16 50 mm Long side accelerating to the right side (+ side) FIG. 17 50 mm Long side accelerating to the left side (− side) FIG. 100mm Long side accelerating to the right side (+ side) Fig. 19 100mm Long side accelerating to the left side (-side) (Description of legends in Figs. 16 to 19) No drift: +/- symmetrical immersion nozzle without blockage
100% stirring force on both sides-Uniform EMS: Immersion nozzle closed asymmetrically, + side,-side
Agitating force of 100% on both sides-Weak side: Immersion nozzle closed asymmetrically, + side is 1
00%,-side is 50% stirring power-side is slightly weak: immersion nozzle closed asymmetrically, + side is 1
00%,-side is 75% stirring power + side is weak: Asymmetrically closed immersion nozzle, + side is 5
0%, the minus side is 100% stirring power

From these results, the following can be considered.
First, it can be seen that under the condition of no drift, the stirring flow rate can be secured over the entire lengthwise direction of the mold. Further, under the condition that the immersion nozzles are closed asymmetrically, the stirring force is “uniform E”.
In the case of "MS", a stagnation with a low stirring flow rate is generated near the immersion nozzle, but by controlling the stirring force to "-side slightly weak", the stirring flow rate is recovered almost uniformly as a whole. You can see that it is.

Example 3 FIGS. 20 and 21 show the results of the measurement of 0.3 m required to prevent inclusions from being caught in the solidified shell under the conditions shown in FIGS.
6 is a graph showing a region ratio where a flow rate of / min or more can be secured. As is clear from this result, "no drift"
In this case, the area ratio is about 76% on the + side and the-side at a depth of 50 mm from the meniscus, and a sufficient effect of reducing inclusion defects can be expected.

On the other hand, when the drift occurs, the "uniform EMS"
In this case, while the-side area ratio is improved to 85%, the + side area ratio is greatly reduced to 47%, and there is a high possibility that inclusions on the surface layer of the slab are deteriorated. In this case, the area ratio on the positive side can be improved by slightly weakening the stirring force of the linear motor on the negative side. However, if the stirring force on the negative side is too weak, the area ratio on the negative side is greatly reduced.
The stirring force needs to be appropriately controlled according to the degree of drift.

Further, as in the above calculation conditions, under the condition that the lower end of the iron core of the linear motor is lower than the lower end of the discharge hole, even if the meniscus flow rate from the short side on the left side toward the immersion nozzle is faster, the molten steel flows from the left side to the right side. Decreasing the agitating force on the + side that accelerates the turbulence, rather promotes drifting,
It is expected that good results cannot be obtained with such electromagnetic stirring.

[0046]

According to the present invention, there is provided a slab in which non-metallic inclusion defects in the surface layer are effectively reduced by appropriately controlling the flow of molten steel in a mold in continuous casting. Has been realized.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a state of molten steel flow in a mold in conventional slab continuous casting.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a schematic explanatory view showing a configuration example of a immersion nozzle in a conventional apparatus.

FIG. 4 is a schematic explanatory view showing an example of an apparatus configuration for implementing the method of the present invention.

FIG. 5 is a diagram for explaining a control procedure in the method of the present invention.

FIG. 6 is a diagram for explaining a relationship between a molten steel flow rate and a stirring force distribution.

FIG. 7 is a diagram for explaining a state of a discharge flow when the upper end position of the operation of the linear motor is higher than the lower end of the discharge hole of the immersion nozzle.

FIG. 8 is a view for explaining a state of a discharge flow when the upper end position of operation of the linear motor is lower than the lower end of the discharge hole of the immersion nozzle.

FIG. 9 is a graph showing an example of setting conditions when operating two linear motors.

FIG. 10 is a graph showing the influence of the presence or absence of drift control on the drift occurrence time occurrence rate.

FIG. 11 is a graph showing the effect of the presence or absence of drift control on the rate of occurrence of surface defects on a thin plate.

FIG. 12 is a vector diagram showing a flow velocity distribution in a central section of a mold thickness in a state where electromagnetic stirring is not performed.

FIG. 13 is a graph showing an example of a calculation result of a component in a long side direction of a mold at a depth position below a meniscus.

FIG. 14 is a graph showing another example of the calculation result of the component of the flow velocity at each depth position below the meniscus in the longitudinal direction of the mold.

FIG. 15 is a graph showing still another example of the calculation result of the component of the flow velocity at each depth position below the meniscus in the long side of the mold.

FIG. 16 is a graph showing an example of a calculation result of a component of a flow velocity in a longitudinal direction of a mold when electromagnetic stirring is performed.

FIG. 17 is a graph showing another example of the calculation result of the component of the flow velocity in the long-side direction of the mold when electromagnetic stirring is performed.

FIG. 18 is a graph showing still another example of the calculation result of the component of the flow velocity in the longitudinal direction of the mold when electromagnetic stirring is performed.

FIG. 19 is a graph showing another example of the calculation result of the component of the flow velocity in the long side direction of the mold when electromagnetic stirring is performed.

FIG. 20 is a graph showing an area where a flow velocity of 0.3 m / min or more can be secured at a position 50 mm deep from the meniscus.

FIG. 21 is a graph showing a region where a flow velocity of 0.3 m / min or more can be secured at a position at a depth of 100 mm from the meniscus.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takehiro Nakaoka 1-5-5 Takatsukadai, Nishi-ku, Kobe City Inside Kobe Steel Research Institute Kobe Steel Co., Ltd. (72) Inventor Yasuhiko Koga Kanazawacho, Kakogawa City, Hyogo Prefecture No. 1 Kobe Steel, Ltd. Kakogawa Works (72) Inventor Masaru Nakao 1 Kanazawa-cho, Kakogawa City, Hyogo Prefecture Kobe Steel Co., Ltd. Kakogawa Works F-term (reference) 4E004 AA09 MB12 MB15 MB17 PA04

Claims (4)

[Claims] A molten steel flow discharged from a submerged nozzle installed in the center of a mold of a continuous casting machine for producing a slab slab having a rectangular cross section into both sides of a short side of the mold is supplied to a linear motor. In the method of performing electromagnetic stirring while accelerating, molten steel in the vicinity of the long side mold wall is accelerated horizontally and in opposite directions to each other by a pair of linear motors provided along the long side of the mold, respectively. When the difference in the height of the molten steel meniscus near the short side mold wall exceeds a set value, a linear motor that accelerates molten steel from the short side of the high meniscus to the short side of the low meniscus. An electromagnetic stirring method in a continuous casting mold, wherein the operation is performed by controlling the stirring force so as to be larger than the stirring force of the other linear motor. 2. An operation upper end position of both linear motors is set within a range of ± 50 mm of a reference meniscus height in a mold, and an operation lower end position of both linear motors is lower than a discharge hole lower end of an immersion nozzle. The electromagnetic stirring method according to claim 1, wherein the method is arranged and operated. 3. The stirring force of each linear motor is controlled by measuring the height of the meniscus of molten steel in the vicinity of the short side mold wall on both sides and changing the current value or frequency of both linear motors based on the measurement result. The electromagnetic stirring method according to claim 1 or 2, wherein: 4. The linear motor according to claim 1, wherein a different stirring force is generated in each linear motor when the difference between the average values of the heights of the molten steel meniscus in the vicinity of the short side mold walls on both sides becomes 15 mm or more. The electromagnetic stirring method according to any one of the above.