JPH05277692A - Method for restraining channeling flow of molten steel in continuous casting mold - Google Patents

Abstract

PURPOSE:To restrain the channeling flow of molten steel by detecting temp. distribution with thermocouples embedded in the width direction of the long sides in a mold, shifting a slide plate and leaning the main stream of the molten steel in an immersion nozzle. CONSTITUTION:At the time of pouring the molten steel into the mold 4 from one pair of the discharging holes 8 at the right and left sides in the immersion nozzle 3, by detecting the temp. distribution with the thermocouples 16a-16g arranged in the width direction of the long sides, the molten channeling flow is detected. If the development of the channeling flow is detected, the sliding plate 2b in a sliding nozzle 2 is shifted in the direction of both discharging holes 8 as centering the full opening position to lean the molten steel main stream 11 flowed down in the immersion nozzle 3 at the inner hole 14. By this method, i.e., by the reverse channeling flow action to the molten main stream 11, the channeling flow of the molten steel is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention makes it possible to suppress the drift of molten steel injected from a dipping nozzle into a mold while controlling the position of a sliding nozzle attached to a tundish. The present invention relates to a method for suppressing molten steel drift in a continuous casting mold.

[0002]

2. Description of the Related Art Conventionally, molten steel is poured from a tundish into a mold in continuous casting, as shown in FIG. 18, by using the tip of a dipping nozzle 3 located below a sliding nozzle 2 provided at the bottom of the tundish 1 into the mold. It is performed while being immersed in the molten steel 5 of No. 4 in FIG. An upper nozzle 6 is provided in the tundish 1, and a sliding nozzle composed of a three-layer plate including a fixed plate 2a, a slide plate 2b, and a lower plate 2c each having an opening with the same inner diameter at a lower portion of the upper nozzle 6. 2 is attached to the slide plate 2 between the fixed plate 2a and the lower plate 2c.
b is slid using the hydraulic cylinder 7 to control the aperture restriction position to control the molten steel flow rate from the inside of the tundish 1.

An immersion nozzle 3 connected to the lower part of the sliding nozzle 2 is arranged at the center of a continuous casting mold 4 having short sides and long sides, and the molten steel in the tundish 1 is opened in the sliding nozzle 2. The continuous casting mold 4 is made to flow from the left and right discharge holes 8 by flowing down the immersion nozzle 3 while controlling the throttle position.
Is injected into. After the molten steel 5 injected from the discharge holes 8 collides with the solidified shell 9 on the short side, it is divided into an upflow and a downflow, but in a steady state, the amount of molten steel injected from the left and right discharge holes 8 becomes equal. As a result, the ascending flow and the descending flow are decelerated while flowing, so that troubles due to the ascending and descending flows do not occur.

As shown in FIG. 19, the fixed plate 2a
And a slide plate 2b, the immersion nozzle 3 is connected to the lower part of the sliding nozzle 2, and the immersion nozzle 3 is slid together with the slide plate 2b by a hydraulic cylinder 7 to control the aperture restriction position. In some cases, a plate is used, and in the same manner, the aperture drawing position is controlled to adjust the molten steel injection amount.

As described above, in continuous casting, as shown in FIGS. 18 and 19, the molten steel injection amount from the tundish 1 into the continuous casting mold 4 is controlled by the sliding nozzle 2, but the lower part of the immersion nozzle 3 is controlled. The flow rate of the molten steel 5 injected into the continuous casting mold 4 from the pair of left and right discharge holes 8 provided on the left and right may be different from each other on the left and right, and uneven molten steel flow may occur.

One of the causes of such molten steel drift is that when the immersion nozzle 3 is used as shown in FIG.
A deoxidation product such as alumina present in the molten steel forms deposits 10 on the inner surface of the inner hole 14 of the dipping nozzle 3 and the discharge hole 8 or the refractory material in the discharge hole is melted by the molten steel flow and discharged left and right. The shape of the holes 8 becomes non-uniform. As a result, the passage cross-sectional area of the discharge hole 8 becomes large and small, and the injection amount into the continuous casting mold 4 becomes large when the passage sectional area is large and becomes small when it is small.

Another cause of drift of molten steel is that it is usually injected with the opening of the sliding nozzle 2 narrowed in order to control the injection amount of molten steel as shown in FIG. Main stream of molten steel flowing down the immersion nozzle 3
Does not pass through the center of the inner hole 14 and is biased to the left or right. This is because the amount of molten steel that is injected into the continuous casting mold 4 from the pair of left and right discharge holes 8 under the influence of this is large in one and small in the other.

As shown in FIG. 16, the discharge hole 8 of the immersion nozzle 3
When the deposit 10 such as alumina adheres to the molten steel, it impedes the injection of the molten steel, so that the required amount of molten steel is secured. For example, when the sliding nozzle 2 is fully opened, the molten steel main flow that flows down in the immersion nozzle 3 is used. 11 is located in the center of the inner hole 14. At this time, if there is no deposit such as alumina, the amount of molten steel injected from the left and right discharge holes 8 will be uniform, but the discharge holes 8
If the deposits 10 formed inside are different on the left and right, the cross-sectional area of the passage becomes uneven on the left and right. That is, when the amount of the deposit 10 on the right side is small and the amount of the deposit 10 on the left side is large, the cross-sectional area of the molten steel passage of the discharge hole 8 is large on the right side and small on the left side. For this reason, the equal relationship of the amount of molten steel injected from the left and right discharge holes 8 is broken, and the amount on the right side is increased and the amount on the left side is decreased, causing so-called molten steel drift.

On the right side where the amount of molten steel injected from the discharge hole 8 of the immersion nozzle 3 is large, the collision force against the solidified shell 9 formed in the short side 4a is large, and the molten steel moves upward along the inner surface of the solidified shell 9 and The flow will be divided downwardly. In this way, the strong upward flow causes rise of the molten metal surface 12 and prevents the flux 13 on the molten metal surface from being supplied between the inner wall surface of the mold 4 and the solidification shell 9, resulting in insufficient supply. The formation of the solidified shell 9 becomes non-uniform and causes not only wrinkles and cracks in the cast slab, but also causes non-metallic inclusion physical defects in the slab by entraining the flux 13. Further, the rightward descending flow, which has a strong influence, reaches deep into the molten steel 5 and hinders the floating of the non-metallic inclusions, and is trapped by the solidified shell 9 and causes defects in the non-metallic inclusions of the slab.

On the other hand, on the left side where the amount of molten steel injected from the discharge hole 8 is small, the collision force against the solidified shell 9 formed in the short side 4a is small, and the molten steel moves upward and downward along the inner surface of the solidified shell 9. The shunting power is weak. For this reason, the trouble on the right side does not occur, but since the molten steel flow rate is small, stagnation is likely to occur due to the molten steel flow in the discharge holes 8 and nozzle clogging is likely to occur due to the adhesion of alumina etc. Not only is it difficult to impair productivity, but also the refractory cost increases due to replacement of the immersion nozzle.

[0011] Once the uneven flow occurs in this way, it is difficult to eliminate it, and when the uneven flow becomes severe, operational troubles such as breakout due to remelting of the solidified shell 9 formed in the mold 4 occur. In addition, a slab surface defect easily occurs due to fluctuations in the molten metal level in the mold 4, and in the worst case, the casting must be stopped. As described above, if the amount of molten steel discharged from the left and right discharge holes 8 is different due to the uneven flow generated in the immersion nozzle 3, not only the operation of continuous casting is hindered but also the quality of the slab is deteriorated, which is not preferable.

Therefore, in order to suppress the uneven flow of molten steel that flows out of the discharge hole of the immersion nozzle into the continuous casting mold, uneven distribution of molten steel is disclosed in JP-A-62-252649. The difference is detected, and a cylindrical porous refractory for gas injection, which is divided into two parts in the vertical direction to the left and right in the vertical direction, is fitted and the amount of gas supplied from the outside to each refractory is suppressed by the molten steel level difference. A method of independently controlling so as to do so is disclosed. However, this method has the drawbacks that the efficiency as a gas actuator is weak, the response is poor, it is difficult to suppress the drift of molten steel with high accuracy, and the melting loss of the porous refractory is significant and the life is short.

Further, in Japanese Laid-Open Patent Publication No. 62-252650, the level difference between the molten steel on the left and right of the immersion nozzle is detected, and a translational electromagnetic stirring device installed directly under the mold is controlled to eliminate the level difference by electromagnetic stirring. A method of adjusting the above is disclosed. However, in the method using an electromagnetic stirrer (EMS) disclosed in JP-A-62-252650, the relationship between the degree of drift and the stirring force for eliminating it is not specified.
If a constant stirring force is used, the change in molten steel flow over time (dynamics) is not taken into consideration, and there is a problem in control accuracy. In addition, a device for electromagnetic stirring becomes large in size, which increases equipment cost and power consumption.

[0014]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and the immersion is performed without adjusting large-scale equipment only by adjusting the aperture stop position of the sliding nozzle provided in the lower part of the tundish. An object of the present invention is to provide a method for suppressing molten steel drift in a continuous casting mold that can balance the amount of molten steel injected from a pair of left and right discharge holes of a nozzle.

[0015]

According to the present invention for achieving the above object, an immersion nozzle having discharge holes extending to the left and right short sides is arranged at the center of a continuous casting mold having short sides and long sides. When the molten steel in the tundish is poured into the continuous casting mold from the discharge hole by making it flow down in the immersion nozzle while controlling the opening throttle position of the sliding nozzle, the left and right molten steel flowing out from the discharge hole of the immersion nozzle. Detecting molten steel uneven flow in which the amounts are uneven, and opening the sliding nozzle so that the path of the molten steel main flow that flows down in the immersion nozzle moves from the discharge hole side where the molten steel drift is small to the large discharge hole side A method for suppressing molten steel drift in a continuous casting mold, characterized in that the molten steel drift is suppressed by a reverse drift effect of a molten steel main flow flowing down in the immersion nozzle.

In the present invention, the temperature distribution in the long side width direction of the continuous casting mold is detected, and the temperature distribution of the right half in the long side width direction and the left half of the temperature distribution with the center of the continuous casting mold as a boundary. It is preferable to compare with the temperature distribution of No. 3 and to detect a molten steel drift that causes uneven amounts of molten steel flowing out from the discharge holes of the immersion nozzle due to the temperature level.

[0017]

[Operation] As shown in Figure 17, sliding nozzle 2
When the molten steel flow rate is controlled by setting the opening of No. 3 to be narrowed down and the molten steel is made to flow down in the immersion nozzle 3, when molten steel is injected into the mold 4 from the pair of left and right discharge holes 8, it is made to flow down in the immersion nozzle 3. The path of the molten steel main flow 11 is biased to either the left or right side in the inner hole 14 in the opening / closing direction of the sliding nozzle 2.

When the sliding nozzle 2 is fully opened and injected as shown in FIG. 16, the molten steel main flow 11 flowing down in the immersion nozzle 3 passes through the center of the inner hole 14. However, if the aperture nozzle injection is performed with the sliding nozzle 2 squeezed, when the slide plate 2b slides between the fixed plate 2a and the lower plate 2c, the side where the opening of the sliding nozzle 2 starts to open, in FIG. It flows toward the left side of the inner hole 14 in the immersion nozzle 3 in a biased manner,
The molten steel main flow 11 is biased to the left of the inner hole 14.

In this way, when the molten steel main flow 11 flowing down the inner hole 14 of the immersion nozzle 3 is biased to the left side, a large amount of molten steel is discharged from the right side discharge hole 8 on the opposite side of the left and right discharge holes 8.
A phenomenon occurs that the amount of molten steel on the left side decreases. This phenomenon occurs when the molten steel main stream 11 that flows downward in the inner hole 14 of the submerged nozzle 3 to the left collides with the molten metal surface in the submerged nozzle 3 and changes from the left and right discharge holes 8 into a horizontal shunt. At this time, the amount of molten steel in the immersion nozzle 3 is large on the right side of the downflow point where the molten steel main stream 11 collides with the molten metal surface, and small on the left side. For this reason, the main molten steel flow 11 guides a large amount of molten steel below the molten metal present on the right side and discharges it from the discharge hole 8 on the right side, so that the injected molten steel amount on the right side increases and the injected molten steel amount on the left side relatively decreases. It is estimated to be.

According to the present invention, the molten steel main stream 11 flowing down in the immersion nozzle 3 is bored by the aperture restriction of the sliding nozzle 2.
By utilizing the effect that the amounts of molten steel that are biased in 14 and injected into the mold 4 from the left and right discharge holes 8 become uneven on the left and right
It is intended to suppress the drift of molten steel caused by the influence of the deposit 10 formed inside. By the way, conventionally, for example, as shown in FIG. 15, a three-layer sliding nozzle 3 including a fixed plate 2a, a slide plate 2b, and a lower plate 2c is a slide plate 2 shown in FIG.
From the state in which the hole is completely closed by b, to the state in which the slide plate 2b shown in FIG. 15 (b) fully injects the left side opening of the aperture to the fully opened hole by the slide plate 2b shown in FIG. 15 (c). It was controlled by the reciprocating stroke.
For this reason, in the conventional case where the slide plate 2b is injected with the aperture restriction, the side where the aperture starts to be opened is always one side.
As shown in FIG. 15 (b), the flow rate of molten steel was controlled by the injection of holes in the sliding nozzle 2 with the molten steel main flow 11 being biased to the left side of the immersion nozzle 3.

On the other hand, according to the present invention, the sliding nozzle 2 has a role of controlling the molten steel flow rate and suppressing the molten steel drift, so that the sliding plate 2b shown in FIG. 11 (b), the opening by the slide plate 2b is left-sided, and the opening by the slide plate 2b shown in FIG. 11 (c) is fully opened.
The opening right side opening by the slide plate 2b shown in (d) and the opening throttle control by the reciprocating stroke until the opening is completely closed by sliding to the opposite side by the slide plate 2b shown in FIG. 11 (e) are performed. Become. Therefore, the opening / closing stroke of the slide plate 2b needs to be twice as long as the conventional opening / closing stroke shown in FIG.

Thus, the left side deviation of the molten steel main stream 11 due to the left side opening of the slide plate 2b shown in FIG. 11 (b) and the slide plate 2b shown in FIG. 11 (d).
The right-sided deviation of the molten steel main flow 11 due to the right-sided opening of the injection hole caused by the opening, and the deviation of the injected molten steel due to the nozzle clogging due to the deposits generated in the pair of left and right discharge holes 8 of the immersion nozzle 3 during continuous casting Is suppressed.

When the three-layer sliding nozzle 2 is used, the slide plate 2b in contact with the fixed plate 12a is slid by using the hydraulic cylinder 7a as shown in FIG. 13, and the lower plate 2c is moved by the hydraulic cylinder 7b. It can also be made slidable individually. Using such a sliding nozzle 2, for example, in order to bias the molten steel main flow 11 flowing down the immersion nozzle 3 to the left side in the inner hole 14, a combination of the slide plate 2b and the lower plate 2c with respect to the fixed plate 2a is illustrated. By setting the positional relationship as shown in 14 (a) to 14 (d), it becomes possible to create various aperture stop states by opening the left side of the aperture.

The following merits can be obtained by creating such various aperture stop conditions. As shown in FIG. 11, when only the slide plate 2b is slid to set the aperture stop position, the slide plate 2b is significantly worn and requires early replacement.
When the lower plate 2c is also slidable, the molten steel main flow 11 flowing down in the immersion nozzle 3 is kept at a certain position by changing the positional relationship of the apertures of the plates as shown in FIG. Since it is possible to disperse the wear of each plate, it is possible to extend the replacement period of the plates. In addition, the molten steel main flow 11 flowing down in the immersion nozzle 3 is bored.
Needless to say, the biasing to the right of 14 can be achieved by making the positional relationship opposite to the case shown in FIGS. 14 (a) to 14 (d).

Further, the present invention can be applied to a two-layer sliding nozzle, and the slide plate 2b shown in FIG. 12 (a) completely closes the opening, and the slide plate 2b shown in FIG. 12 (b) left side the opening. One-sided opening, full opening by slide plate 2b shown in FIG. 12 (c), one-sided opening by slide plate 2b shown in FIG.
The opening of the slide plate 2b shown in (e) is completely closed by sliding on the opposite side. In this case, due to the opening of the left side of the opening shown in FIG. 12 (b), the molten steel main flow 11 flowing down in the immersion nozzle 3 is biased to the left side, and the opening of the right side of the opening shown in FIG. The molten steel main flow 11 flowing down inside is biased to the right.

As shown in FIG. 8, the molten steel 5 in the tundish 1 is made to flow down in the dipping nozzle 3 while controlling the aperture narrowing position of the sliding nozzle 2 to form a pair of left and right discharge holes 8.
In the continuous casting process of pouring from the continuous casting mold 4 into the continuous casting mold 4,
When the amount of molten steel injected from the left and right discharge holes 8 is large on the right side and small on the left side due to the deposit 10 such as alumina adhered on the right side, the molten steel drift 15 causes the right side molten metal surface 15 to be higher than the left side. When such molten steel drift occurs, the sliding plate 2b of the sliding nozzle 2 is slid to the right as shown in FIG. Downstream molten steel mainstream 11
Is biased to the right of the inner hole 14 to take an action to increase the flow rate of molten steel injected from the left discharge hole 8 into the continuous casting mold 4. If such an action is taken, deposits 10
If there is not, the level 15 on the left side is higher than the level on the right side.

In practice, the deposit 10 on the discharge hole 8 causes a molten steel drift that causes the flow rate of the molten steel discharged from the discharge hole 8 on the right side to be larger than that on the left side.
As shown in 10, the increase in the molten steel flow rate to the right side discharge hole 8 is canceled by the inductive action of increasing the molten steel flow rate to the left discharge hole 8 due to the deviation of the molten steel main flow 11 flowing down in the immersion nozzle 3 to the right side. Therefore, molten steel drift is suppressed. As a result, the left and right molten metal surfaces 15 in the continuous casting mold 4 are equalized, and the trouble due to molten steel drift is eliminated.

In the present invention, as a means for detecting the magnitude of the molten steel drift that causes the amounts of molten steel flowing out from the discharge holes of the immersion nozzle to be non-uniform, the difference between the left and right levels of molten steel in the continuous casting mold is detected. It is possible to use a level gauge such as a vortex flow level sensor, or a means for detecting the temperature difference between the left and right by a temperature sensor embedded in the height direction of the short side of the continuous casting mold. It is highly reliable to detect the temperature distribution in the long side width direction with multiple thermocouples embedded in the width direction and compare the temperature distributions on the left and right sides to estimate the molten steel level difference between the left and right sides and detect molten steel drift. Optimal.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific examples suitable for carrying out the present invention will be described below with reference to the drawings. FIG. 2 is a perspective view schematically showing an embodiment according to the present invention. As shown in the drawing, a plurality of thermocouples 16a to 16g are embedded in the long side width direction of the short side 4a and the long side 4b of the continuous casting mold (hereinafter referred to as the mold) 4,
The temperature in the long side width direction is detected by these thermocouples 16a to 16g.

FIG. 3 shows a case in which no drift occurs (a).
When the above occurs, the temperature distribution in the width direction of the mold in (b) is shown. When there is no drift shown in (a), the temperature distribution in the long side width direction of the mold is almost symmetrical, whereas
When the drift shown in (b) occurs, the temperature distribution in the width direction of the long side of the mold becomes asymmetrical (when the drift occurs on the right side, the temperature becomes higher than on the right side).

FIG. 4 is a schematic diagram for explaining a method for estimating the degree of drift. That is, with respect to the temperature distribution obtained by the temperature measurement, an integer “1” is given to the lowest temperature measurement value, and an integer value is sequentially increased from the measurement value to a higher value. The sum of the ranks of and the sum of the ranks of the left half are compared, and the difference between them is used to estimate the direction of the drift and the degree of the drift.

FIG. 5 is a diagram showing the relationship between the difference of rank sums derived by this method (marked by .largecircle.) And the difference in molten steel level inside the mold caused by drift (marked by x). The figure shows that the difference between the rank sums and the actual molten steel level difference are in good agreement, indicating that the direction and degree of drift according to the method of the present invention have been successfully estimated. The temperatures detected by the plurality of thermocouples 16a to 16g embedded in the width direction of the long side 4b of the mold 4 are input to the temperature comparison calculator 20 as shown in FIG.
Here, the temperature distribution in the width direction of the long side 4b is monitored. Then, from the temperature distribution of the right half and the left half in the long side width direction, the rank sum of the right half and the rank half of the mold 4 from the center of the mold 4 is compared by the above-mentioned procedure, and the difference is calculated from the discharge holes 8 on the left and right sides of the mold 4. Inhomogeneous flow of the amount of molten steel injected into the inside, that is, the direction and size of the drift of molten steel are estimated. This is based on the principle that the long side on the side where the flow rate of molten steel is high becomes larger due to the uneven flow of molten steel than on the side where the flow rate is low, and the temperature rises.
In the case of FIG. 1, it is determined that the amount of molten steel injected from the discharge hole 8 on the right side is large and the flow is uneven.

In the temperature comparison calculator 20, a deviation signal corresponding to the calculated molten steel drift is input to the drift control controller 21. In the non-uniform flow control controller 21, the current position signal of the hydraulic cylinder 7, that is, the position of the immersion nozzle 3 is fetched from the potentiometer 22 to correct the position of the slide plate 2b to correct the position of the slide plate 2b. In response to this, a position change command to the left or right side of the slide plate 2b is output. The output of the non-uniform flow controller 21 is a solenoid valve installed in the hydraulic pressure supply circuit.
When the solenoid valve 23 is actuated, the hydraulic supply circuit from the hydraulic pump 24 is switched to control the advance and retreat of the hydraulic cylinder 7. 25 indicates an oil tank.

In the case shown in FIG. 1, since it is detected that the amount of molten steel injected from the right side of the pair of left and right discharge holes 8 of the immersion nozzle 3 is larger than that on the left side, the hydraulic cylinder 7 is detected. The slide plate 2b is slid to the right by the operation of, and the sliding nozzle 3 is changed from the opening left side open to the opening right side open, and the molten steel main flow 11 flowing down in the immersion nozzle 3 is indicated by a solid line from the left side in a dotted line. Bias to the right of the bore 14 as shown. Such molten steel mainstream 11
It is possible to suppress the molten steel from flowing into the right side discharge hole 8 by the inducing action of increasing the amount of molten steel into the left side discharge hole 8 by switching to the right side, and to equalize the left and right molten steel amounts.

When the above-described operation is repeated at a certain timing until the difference between the right and left temperature ranks in the widthwise direction of the mold 2 becomes less than or equal to the threshold value, the molten steel main flow 11 flowing down in the dipping nozzle is bored. Due to the effect of suppressing the molten steel drift due to the deviation at 14, the molten steel is evenly distributed from the left and right discharge holes 8 into the mold 4, and the molten steel drift is suppressed. The case of implementing the present invention will be described with reference to FIG. About 70 minutes after casting started,
The absolute value of the difference ΔS, which is obtained by subtracting the left half surface rank sum from the right half surface rank sum in the long side width direction, is stable at a low value of 2 or less, indicating that the molten steel flow in the mold is even on the left and right (the appropriate range for ΔS is Within ± 4). After that, the left-right rank sum difference ΔS changed largely in the positive direction (indicating that the current drifted to the right).

Therefore, when the slide plate of the three-layer sliding nozzle is slid to the left to switch the opening from left-sided opening to right-sided opening, the left-right rank sum difference ΔS returns to the proper range at about 115 minutes. It was It is considered that this operation caused the flow of molten steel in the mold to return to a uniform level. FIG. 7 shows the slab quality before and after the nonuniform flow control is performed. It can be seen that the quality of the cast slab is greatly improved by applying the present invention.

Instead of detecting the drift by the thermocouple, it is also possible to use a vortex flow level meter which is arranged close to the molten metal surface between the short sides of the immersion nozzle and the mold on both sides of the immersion nozzle. is there. In this case, it is possible to determine that the drift occurs when the level difference of the molten metal detected by the left and right vortex flow level meters due to the rise of the molten metal surface exceeds a predetermined threshold value.

[0038]

As described above, according to the present invention, it is possible to easily prevent the drift of the molten steel injected into the mold through the discharge hole of the immersion nozzle by the throttle injection of the sliding nozzle provided in the lower part of the tundish. be able to. As a result, the nozzle clogging of the immersion nozzle is halved and not only is it possible to carry out continuous casting, but also it is possible to stably produce slabs without defects, and it is possible to reduce sliver defects of cold rolled materials. A great effect can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing an arrangement of devices according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing a long side width direction temperature measuring means for a mold according to the present invention.

FIG. 3 is a line graph showing the temperature distribution in the long side width direction of the mold.

FIG. 4 is a line graph showing the temperature ranking of the temperature distribution in the long side width direction of the mold.

FIG. 5 is a line graph showing a relationship between a molten steel level difference in a mold and a difference in temperature rank sum indicated by a solid line.

FIG. 6 is a line graph showing changes over time in the temperature order sum difference on the left and right in the long side width direction of the mold.

FIG. 7 is a bar graph comparing slab quality between an example of the present invention and a conventional example.

FIG. 8 is a cross-sectional view showing a molten steel pouring state when deposits are present in the discharge holes of the immersion nozzle.

FIG. 9 is a cross-sectional view showing a molten steel injection state by opening the right side of the opening of the sliding nozzle.

FIG. 10 is a cross-sectional view showing a situation in which molten steel is prevented from drifting due to opening of the sliding nozzle on the right side of the opening when there is a deposit in the discharge hole.

FIG. 11 is a cross-sectional view showing how to adjust the aperture restriction position of the three-layer sliding nozzle.

FIG. 12 is a cross-sectional view showing how to adjust the aperture restriction position of a two-layer sliding nozzle.

FIG. 13 is a cross-sectional view showing a structure in which a lower nozzle of a three-layer sliding nozzle is slidable.

FIG. 14 is a cross-sectional view showing a variation of the aperture restriction state when the lower nozzle of the three-layer sliding nozzle is made slidable.

FIG. 15 is a cross-sectional view showing a state of adjusting an opening position of a conventional three-layer sliding nozzle.

FIG. 16 is a cross-sectional view showing a molten steel pouring state in a case where there is a deposit in a discharge hole of the immersion nozzle and the sliding nozzle is fully opened.

FIG. 17 is a cross-sectional view showing a state where molten steel is injected by the single opening of the left side of the opening of the sliding nozzle without any deposit in the discharge hole of the immersion nozzle.

FIG. 18 is a cross-sectional view showing a molten steel injection state from a three-layer sliding nozzle at a steady state.

FIG. 19 is a cross-sectional view showing how molten steel is injected from the two-layer sliding nozzle in a steady state.

[Explanation of symbols]

 1 Tundish 2 Sliding Nozzle 3 Immersion Nozzle 4 Continuous Casting Mold 5 Molten Steel 6 Upper Nozzle 7 Hydraulic Cylinder 8 Discharge Hole 9 Solidifying Shell 10 Deposits 11 Molten Steel Mainstream 12 Hot Metal Surface Rise 13 Flux 14 Inner Hole 15 Hot Water Surface 16 Thermocouple 20 Temperature comparison calculator 21 Non-uniform flow controller 22 Potentiometer 23 Solenoid valve 24 Hydraulic pump 25 Oil tank

Claims (2)

[Claims] 1. A dipping nozzle having discharge holes extending to the left and right short sides is arranged at the center of a continuous casting mold having short sides and long sides, and molten steel in a tundish is drawn at a position where the sliding nozzle is opened. When injecting into the continuous casting mold through the discharge hole by flowing down the inside of the immersion nozzle while controlling the, the molten steel uneven flow in which the left and right molten steel amounts flowing out from the discharge hole of the immersion nozzle are detected unevenly, the molten steel drift The discharge hole side from the small discharge hole side to the large discharge hole side, the opening narrowing position of the sliding nozzle is set and changed so that the path of the molten steel main flow that flows down in the immersion nozzle moves, thereby flowing down in the immersion nozzle. A method for suppressing molten steel drift in a continuous casting mold, characterized in that the molten steel drift is suppressed by a reverse drift effect caused by a molten steel main flow. 2. The temperature distribution in the long side width direction of the continuous casting mold is detected, and the right half temperature distribution and the left half temperature distribution of the temperature distribution in the long side width direction with the center of the continuous casting mold as a boundary. And compare
The method for suppressing molten steel drift in a continuous casting mold according to claim 1, wherein the molten steel drift caused by uneven amounts of molten steel flowing out from the discharge holes of the immersion nozzle due to the temperature is detected.