JP2011224638A - Apparatus and method for continuously casting steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress degradation of production yield of cast slab while improving quality of the cast slab in continuous casting of steel.SOLUTION: A continuous casting apparatus 1 includes: a cast mold 3 having a pair of long side walls 10 and 11 and a pair of short side walls 12 and 12; and an immersion nozzle 5 for discharging molten steel 4 into the cast mold 3, respectively. Electromagnetic stirring devices 20 and 20 for stirring an upper part of the molten steel 4 in the cast mold 3 are arranged to the long side walls 10 and 11 along outer side walls of the long side walls 10 and 11. At least a concave 21 being recessed from an inner side wall 10b toward the outer side wall 10a side at a position facing the immersion nozzle 5 and a long side wall moving part 22 having a shape conforming to the concave 21 and movable along the thickness direction of the cast mold 3 are disposed on the long side wall 10. The pair of short side walls 12 and 12 are configured to be movable in a width direction of the cast mold 3 when the long side wall moving part 22 is housed in the concave 21.

Description

  The present invention relates to a continuous casting apparatus for steel in which molten steel is supplied into a mold to produce a slab, and to a continuous casting method for steel using the continuous casting apparatus.

  In continuous casting of steel, in order to improve the surface shape of a slab, for example, electromagnetic stirring of molten steel in the mold is performed using an electromagnetic stirring device installed on the upper part of the mold.

  In this electromagnetic stirring, for example, as shown in FIG. 11, electromagnetic stirring devices 101 and 101 are arranged along a pair of long side walls 100a and 100a of the mold 100, respectively. In the illustrated example, the inner side surfaces of the pair of long side walls 100a and 100a are formed in a straight line parallel to each other in plan view based on the shape of a normal mold. When the molten steel 103 is discharged from the immersion nozzle 102 into the mold 100, current is supplied to the electromagnetic stirring device 101, and thrust is applied to the upper molten steel 103 in the mold 100. By this thrust, the molten steel 103 is stirred in a horizontal plane, and a swirl flow 104 of the molten steel 103 is formed. Then, the swirl flow 104 prevents inclusions and the like near the meniscus at the top of the mold 100 from being captured by the solidified shell formed on the side surface of the mold 100.

  However, since the region 105 between the immersion nozzle 102 and the inner side surface of the long side wall 100a is narrow, the flow path of the swirl flow 104 becomes narrow and the molten steel 103 hardly flows. Then, in the region 105, inclusions in the molten steel 103 are easily captured by the solidified shell of the long side wall 100a.

  Therefore, it has been proposed to use the above-described electromagnetic stirring device 101 and to use a so-called irregular mold 110 as shown in FIG. 12 instead of the parallel mold 100. The central portion of the inner side surface of the long side wall 110a of the modified mold 110, that is, the portion facing the immersion nozzle 102 is curved convexly toward the electromagnetic stirring device 101 to form a curved portion 111. Further, linear straight portions 112, 112 are formed on both sides of the curved portion 111 on the inner surface of the long side wall 110 a. The curved portion 111 of the modified mold 110 widens the region 105 between the immersion nozzle 102 and the inner side surface of the long side wall 100a, thereby preventing the flow path of the swirling flow 104 from becoming narrow (Patent Document 1). ).

In order to ensure the flow path of the swirling flow 104 in the above region 105, and a long pair of long sides walls 100a of the mold 100 parallel type as shown in FIG. 13, the distance _{L 1} between the 100a, the mold 100 the distance between the pair of pressure rolls 120 and 120 in which a plurality arranged downstream is narrowed toward the downstream side of, it has been proposed to cast a predetermined slab thickness L ₂ (Patent Document 2).

JP 2008-183597 A Japanese Patent No. 3008821

  However, when the atypical mold 110 of Patent Document 1 is used, the horizontal width B along the long side wall 110a of the curved portion 111 is the minimum width for securing the flow path of the swirling flow 104 as shown in FIG. Therefore, a slab having a width smaller than the width B cannot be cast. In other words, when the atypical mold 110 is used, the degree of freedom of the width of a cast piece that can be cast is reduced.

  In addition, when the atypical mold 110 is used, the flow of the swirl flow 104 is partially disturbed, and there is a possibility that a region where some inclusions are easily trapped by the solidified shell may be generated. That is, since the swirl flow 104 a flowing along the curved portion 111 flows with the same curvature as the curvature of the curved portion 111, the swirl flow 104 b flowing on the downstream side flows in a direction away from the straight portion 112. Therefore, the molten steel 103 hardly flows in the most downstream side of the straight portion 112, that is, in the region 121 near the corner portion of the modified mold 110. Then, in the region 121, inclusions in the molten steel 103 are easily captured by the solidified shell.

On the other hand, when the mold 100 and the rolling roll 120 of Patent Document 2 are used, first, when a dummy bar (not shown) passes, the opposing distance between the first pair of rolling rolls 120 and 120 is the length of the pair of molds 100. -side wall 100a, has the same length as the distance _{L 1} between 100a. Thereafter, the dummy bar is passes through the plurality of pressure rolls 120, 120, casting the gradually narrowing to a predetermined thickness L ₂ slab as goes opposing distance of a pair of pressure rolls 120 and 120 on the downstream side. In such a case, the cast slab of thickness dummy bar is a pair of pressure rolls 120, 120 after the passage is cast before moving to a predetermined position (until the steady operation state), is thicker than a predetermined thickness L ₂ . Therefore, after continuous casting, it is necessary to remove the thicker slab than the predetermined thickness L _2, so that the decrease in yield of the slab occurs.

  This invention is made | formed in view of this point, and it aims at suppressing the fall of the yield of a slab, improving the quality of a slab in continuous casting of steel.

  In order to achieve the above object, the present invention is a continuous casting apparatus for steel, which is a molten steel casting mold having a pair of long side walls and a pair of short side walls, and discharges the molten steel into the mold. An immersion nozzle, and an electromagnetic stirring device that is disposed along the outer surface of the pair of long side walls and stirs the upper molten steel in the mold, and at least one of the long side walls is at least the immersion A recess portion recessed from the inner surface to the outer surface side at a position facing the nozzle, and a long side wall movable portion having a shape that fits the recess portion and movable in the thickness direction of the mold, The pair of short side walls are each configured to be movable in the width direction of the mold when the long side wall movable part is accommodated in the recess. The mold thickness direction refers to the direction along the short side wall of the mold, and the mold width direction refers to the direction along the long side wall of the mold.

  According to the continuous casting apparatus of the present invention, when the dummy bar is inserted into the mold, the long side wall movable portion is moved to the immersion nozzle side and arranged, and after the dummy bar passes through the mold, the mold continues to the dummy bar. With the molten steel supplied therein, the long side wall movable part can be moved to the electromagnetic stirrer side and accommodated in the recess. In this way, the long side wall movable part is accommodated in the hollow part, and the area between the inner side surface of the long side wall and the immersion nozzle can be widened during casting of the molten steel. Widely secured. In addition, since the region between the inner side surface of the long side wall and the immersion nozzle is wide and the molten steel flows linearly in this region, the turbulent flow is not disturbed unlike the case of using a conventional atypical mold. Therefore, it is possible to suppress the inclusions in the upper part of the mold from being trapped by the solidified shell on the side surface of the mold, and the quality of the slab can be improved. Moreover, since the thickness of the dummy bar is a desired thickness after casting the cast piece, the distance between a plurality of pairs of the rolling rolls arranged on the downstream side of the mold can be made the same length as the desired thickness. Therefore, after the dummy bar passes through the mold, the molten steel is continuously supplied to the dummy bar, and the long side wall movable part is accommodated in the hollow part so that the thickness of the molten steel in the mold is larger than the desired thickness. Even if the thickness is increased, the thickness of the slab can be set to a desired thickness when the sheet subsequently passes through the reduction roll. Thus, since all the molten steel continuously supplied to the dummy bar can be cast into a slab having a desired thickness, it is possible to suppress a decrease in yield of the slab. Furthermore, according to the continuous casting apparatus of the present invention, the short side wall can be moved in the width direction of the mold in a state where the long side wall movable part is accommodated in the hollow part, so the degree of freedom of the width of the cast piece that can be cast is increased Can be bigger.

  In the case where the hollow portion and the long side wall movable portion are provided only on the one long side wall, the immersion nozzle may be configured to be movable in the thickness direction of the mold. Further, in the case where the hollow portion and the long side wall movable portion are provided only on the one long side wall, the immersion nozzle is connected to a tundish, and the tundish is a thickness of the mold together with the immersion nozzle. It may be configured to be movable in the direction.

  Another aspect of the present invention is a continuous casting method using the steel continuous casting apparatus, wherein when inserting a dummy bar into a mold, the long side wall movable part is moved to the immersion nozzle side and arranged. After the dummy bar passes through the mold, the long side wall movable part is moved to the electromagnetic stirrer side in a state in which molten steel is continuously supplied into the mold in the dummy bar, and is accommodated in the hollow part. Then, the short side wall is moved to a predetermined position. The predetermined position is a position where the distance between the pair of short side walls becomes a desired width after casting the cast piece.

  According to another aspect of the present invention, there is provided a continuous casting method using a continuous casting apparatus for steel in which the immersion nozzle is configured to be movable in the thickness direction of the mold, and when a dummy bar is inserted into the mold. The long side wall movable part is moved and arranged on the immersion nozzle side, and the immersion nozzle is arranged in the center in the thickness direction of the mold in plan view, and after the dummy bar passes through the mold, While the molten steel is continuously supplied into the mold, the long side wall movable part is moved to the electromagnetic stirrer side to be accommodated in the hollow part, and the immersion nozzle is moved to the long side wall movable part side. It is characterized in that it is moved and arranged in the center in the thickness direction of the mold in plan view, and then the short side wall is moved to a predetermined position.

According to another aspect of the present invention, the immersion nozzle is connected to a tundish, and the tundish is configured to be movable in the thickness direction of the mold together with the immersion nozzle. In the casting method, when inserting a dummy bar into a mold, the long side wall movable part is moved to the immersion nozzle side and arranged, and the immersion nozzle is arranged in the center in the thickness direction of the mold in plan view Then, after the dummy bar passes through the mold, the long side wall movable part is moved to the electromagnetic stirrer side in a state where the molten steel is continuously supplied to the mold and accommodated in the hollow part. And moving the tundish to the long side wall movable part side,
The immersion nozzle is arranged in the center in the thickness direction of the mold in plan view, and then the short side wall is moved to a predetermined position.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the yield of a slab can be suppressed, improving the quality of a slab in continuous casting of steel.

It is explanatory drawing which shows the outline of a structure of the continuous casting apparatus concerning this Embodiment. It is explanatory drawing of the cross section which shows the outline of a structure of a casting_mold | template and an immersion nozzle. It is explanatory drawing of the longitudinal cross-section which shows the outline of a structure of a casting_mold | template, an immersion nozzle, and a tundish. It is explanatory drawing of the longitudinal cross-section which shows the outline of a structure of a casting_mold | template, an immersion nozzle, and a tundish. It is explanatory drawing which shows the outline of a structure of the sliding plate for immersion nozzle position adjustment, the sliding plate for flow volume adjustment, and a fixed plate. It is explanatory drawing which shows a mode that the long side wall movable part was moved to the immersion nozzle side. It is explanatory drawing which shows a mode that the long side wall movable part was moved to the electromagnetic stirrer side, it accommodated in the hollow part, and the immersion nozzle was moved to the long side wall movable part side, and was arrange | positioned in the center in a casting_mold | template. It is explanatory drawing which shows a mode that a pair of short side wall was moved to the immersion nozzle side, and each was arrange | positioned in the predetermined position. It is explanatory drawing of the longitudinal cross-section which shows the outline of a structure of the casting_mold | template, immersion nozzle, and tundish concerning other embodiment. It is explanatory drawing of the cross section which shows the outline of a structure of the casting_mold | template and immersion nozzle concerning other embodiment. It is explanatory drawing of the cross section which shows the outline of a structure of the conventional casting_mold | template and an immersion nozzle. It is explanatory drawing of the cross section which shows the outline of a structure of the conventional casting_mold | template and an immersion nozzle. It is explanatory drawing which shows the outline of a structure of the conventional continuous casting apparatus.

  Embodiments of the present invention will be described below. FIG. 1 is an explanatory diagram showing an outline of the configuration of a continuous casting apparatus 1 for steel according to the present embodiment.

  As shown in FIG. 1, the continuous casting equipment 1 passes a tundish 2 for storing molten steel, a dipping nozzle 5 for injecting molten steel 4 into a mold 3 from the bottom of the tundish 2, and a slab 6 drawn from the mold 3. A pair of roll groups 7 and 7 are provided. In the roll group 7, a plurality of reduction rolls 8 for guiding the slab 6 are arranged side by side in the casting direction of the slab 6. Each reduction roll 8 is rotatably provided, and the distance between the pair of reduction rolls 8 and 8 facing each other with the slab 6 interposed therebetween is set to be equal to the desired thickness of the slab 6. The slab 6 is drawn out and conveyed in a predetermined casting direction while being supported with the slab 6 being sandwiched between these rolling rolls 8. In the illustrated example, the slab 6 is cast continuously to the dummy bar 9.

  As shown in FIG. 2, the mold 3 includes, for example, a pair of long side walls 10 and 11 and a pair of short side walls 12 and 12, and has a substantially rectangular horizontal cross-sectional shape. The long side walls 10 and 11 and the short side wall 12 are each composed of a copper plate provided inside and a stainless steel water cooling box provided outside. In the present embodiment, the thickness of the slab 6 cast with the mold 3 is, for example, about 50 mm to 300 mm. Specifically, the required slab thickness is about 50 mm to 80 mm for a thin slab, about 80 mm to 150 mm for a medium slab, and 150 mm for a normal thickness slab. About 300 mm.

  In the pair of long side walls 10 and 11, electromagnetic stirring devices 20 and 20 such as electromagnetic stirring coils are provided, respectively. The electromagnetic stirring devices 20 and 20 are arranged along the outer side surfaces 10a and 11a of the long side walls 10 and 11, respectively.

  In one long side wall 10, a recess 21 that is recessed from the inner side surface 10 b to the outer side surface 10 a side is formed at least at a position facing the immersion nozzle 5. The hollow portion 21 has a rectangular parallelepiped shape penetrating in the vertical direction of the long side wall 10. Further, the long side wall 10 includes a long side wall movable portion 22 that is movable in the thickness direction of the mold 3 (Y direction in FIG. 2). The long side wall movable part 22 is provided with a moving mechanism 23 such as a cylinder, for example, and the long side wall movable part 22 is movable by the moving mechanism 23. As shown in FIG. 3, for example, two moving mechanisms 23 are provided in the vertical direction. Moreover, the long side wall movable part 22 has a rectangular parallelepiped shape which matches the shape of the hollow part 21, as shown in FIG. And the long side wall movable part 22 is accommodated in the hollow part 21 without a level | step difference with the inner surface 10b of the long side wall 10 in which the hollow part 21 is not formed. For example, a fluororesin layer (for example, Teflon (registered trademark of DuPont)) is provided on the side surface of the long side wall movable portion 22, and the long side wall movable portion 22 is a long side in the short side wall 12 or the hollow portion 21. It can move smoothly while contacting the wall 10.

  The pair of short side walls 12, 12 is configured to be movable in the width direction of the mold 3 (X direction in FIG. 2) when the long side wall movable portion 22 is accommodated in the recessed portion 21. The pair of short side walls 12 and 12 are provided with moving mechanisms 24 and 24 such as cylinders, for example, and the short side wall 12 is movable by the moving mechanism 24. As shown in FIG. 4, for example, two moving mechanisms 24 are provided in the vertical direction. For example, a fluorine resin layer (for example, Teflon (registered trademark of DuPont)) is provided on the side surface of the short side wall 12, and the short side wall 12 is in contact with the long side walls 10 and 11 and the long side wall movable portion 22. While being able to move smoothly.

  An immersion nozzle 5 that communicates with the bottom of the tundish 2 is provided in the upper part of the mold 3 as shown in FIGS. Above the immersion nozzle 5, an immersion nozzle position adjusting sliding plate 30, a flow rate adjusting sliding plate 31, and a fixed plate 32 are provided in this order from the immersion nozzle 5 side. The immersion nozzle position adjusting sliding plate 30 and the flow rate adjusting sliding plate 31 are configured to be movable in the horizontal direction with respect to the fixed plate 32, and the immersion nozzle 5 is moved in the thickness direction of the mold 3 by the immersion nozzle position adjusting sliding plate 30. It can move freely in the Y direction in FIG. As shown in FIG. 5, the immersion nozzle position adjusting sliding plate 30, the flow rate adjusting sliding plate 31, and the fixed plate 32 are formed with through holes 30a, 31a, and 32a penetrating in the thickness direction, respectively. Specifically, a through hole 32 a having a long hole shape having a length (Y direction in FIG. 5) corresponding to the moving range of the immersion nozzle 5 is formed in the fixed plate 32. The immersion nozzle position adjusting sliding plate 30 and the flow rate adjusting sliding plate 31 are formed with through holes 30a and 31a each having a shorter length (Y direction in FIG. 5) than the through hole 32a. First, the sliding nozzle 30 for adjusting the immersion nozzle position is moved and arranged at a desired position, and then the opening area between the tundish 2 and the immersion nozzle 5 is moved by moving the sliding plate 31 for adjusting the flow rate. Can be adjusted. Thus, the molten steel 4 can be circulated in the immersion nozzle position adjusting sliding plate 30, the flow rate adjusting sliding plate 31, and the fixed plate 32 while adjusting the flow rate of the molten steel 4.

  The lower part of the immersion nozzle 5 is immersed in the molten steel 4 in the mold 3 as shown in FIGS. Near the lower end of the side surface of the immersion nozzle 5, two discharge holes 40 for discharging the molten steel 4 obliquely downward into the mold 3 are formed. The discharge holes 40 are formed on the short side wall 12 side of the mold 3. The discharge flow 41 discharged from the discharge hole 40 collides with, for example, a solidified shell 42 formed on the short side wall 12 of the mold 3 described later, and branches into an upward flow 43 and a downward flow. The discharge flow 41 includes inclusions 44 such as alumina and slag. The inclusion 44 floats to the vicinity of the meniscus 45 by, for example, the upward flow 43 or the like. A molten powder 46 having a molten oxide is supplied on the meniscus 45.

  As shown in FIGS. 3 and 4, a solidified shell 42 is formed on the inner surface of the mold 3 by cooling and solidifying the molten steel 4.

  The continuous casting apparatus 1 according to the present embodiment is configured as described above. Next, the continuous casting method of the molten steel 4 using this continuous casting apparatus 1 is demonstrated.

First, as shown in FIG. 6, the long side wall movable portion 22 is moved to the immersion nozzle 5 side and disposed, and the immersion nozzle 5 is disposed at the center in the thickness direction of the mold 3 in plan view. At this time, the distance D ₁ between the long side wall movable portion 22 and the long side wall 11 is set to the same length as the thickness of the dummy bar 9. Then, the dummy bar 9 is inserted into the mold 3.

Thereafter, after the dummy bar 9 passes through the mold 3, the molten steel 4 is continuously supplied to the mold 3 in the state where the molten steel 4 is supplied to the electromagnetic stirrer 20 side as shown in FIG. The immersion nozzle 5 is moved to the long side wall movable part 22 side and arranged at the center in the thickness direction of the mold 3 in a plan view while being moved and accommodated in the depression 21. Then, the distance D ₂ between the long side wall movable portion 22 and the long side wall 11 is longer than the distance D _1. Subsequently, as shown in FIG. 8, the pair of short side walls 12, 12 are moved to the immersion nozzle 5 side, for example, and are arranged at predetermined positions. And the distance W between a pair of short side walls 12 and 12 turns into the desired width of the molten steel 4, ie, the desired width of the slab 6 to be cast.

  At this time, as shown in FIG. 4, the molten steel 4 discharged into the mold 3 from the discharge port 40 of the immersion nozzle 5 is discharged obliquely downward and discharged from the discharge hole 40 toward the short side wall 12 of the mold 3. A stream 41 is formed. Inclusions 44 are included in the discharge flow 41, and the inclusions 44 float up to the vicinity of the meniscus 45 by, for example, the upward flow 43 described above.

  Moreover, simultaneously with discharging the molten steel 4 from the immersion nozzle 5, the electromagnetic stirring devices 20 and 20 are operated. By operating these electromagnetic stirrers 20, 20, the molten steel 4 near the meniscus 45 in the mold 3 is stirred in a horizontal plane as shown in FIG. 8, and a one-way swirl flow 50 is formed. At this time, the long side wall movable part 22 is accommodated in the hollow part 21, and the area 51 between the long side wall movable part 22 and the long side wall 11 and the immersion nozzle 5 can be widened. A sufficient flow path of the flow 50 can be secured. Accordingly, in the region 51, the flow of the swirling flow 50 does not stagnate. Further, since the region 51 is wide and the molten steel 4 flows linearly in the region 51, unlike the case of using a conventional atypical mold, the swirling flow 50 is not disturbed. The inclusion 44 that has floated to the vicinity of the meniscus 45 swirls in the horizontal plane in the mold 3 by the swirling flow 50 and is taken into, for example, the molten powder 46 on the meniscus 45 without being captured by the solidified shell 42 of the mold 3. Removed.

  Thereafter, the molten steel 4 from which the inclusions 44 have been removed is solidified and drawn out from the mold 3 and cast into the slab 6. The slab 6 drawn out from the mold 3 passes through the pair of roll groups 7 and 7 and has a desired thickness. Therefore, all the cast pieces 6 continuing to the dummy bar 9 are cast with a desired thickness.

  According to the above embodiment, when the dummy bar 9 is inserted into the mold 3, the long side wall movable portion 22 is moved and arranged to the immersion nozzle 5 side, and after the dummy bar 9 passes through the mold 3, the dummy bar 9 In the state where the molten steel 4 is continuously supplied into the mold 3, the long side wall movable part 22 can be moved to the electromagnetic stirrer 20 side and accommodated in the hollow part 21. Since the long side wall movable part 22 is accommodated in the hollow part 21 in this way, the region 51 between the long side wall movable part 22 or the long side wall 11 and the immersion nozzle 5 can be widened during casting of the molten steel 4. The flow path of the swirling flow 50 that flows through the region 51 can be secured. Therefore, it is possible to suppress the inclusions 44 in the upper part in the mold 3 from being captured by the solidified shell 42 on the side surface of the mold 3 and to improve the quality of the cast slab 6 to be cast.

  Further, since the immersion nozzle 5 is configured to be movable in the thickness direction of the mold 3 along with the movement of the long side wall movable portion 22, the immersion nozzle 5 can also be arranged at the center in the mold 3. Thereby, the area | region 51 between the long side wall movable part 22 and the immersion nozzle 5 and the area | region 51 between the long side wall 11 and the immersion nozzle 5 can be expanded equally. Therefore, a sufficient flow path of the swirling flow 50 flowing through these regions 51 can be secured.

  Further, since the thickness of the dummy bar 9 is a desired thickness after casting of the slab 6, the distance between the plurality of pairs of the rolling rolls 8 and 8 arranged on the downstream side of the mold 3 is set to the same length as the desired thickness. it can. Therefore, after the dummy bar 9 passes through the mold 3, the long side wall movable portion 22 is accommodated in the hollow portion 21 in a state where the molten steel 4 is continuously supplied to the mold 3 after the dummy bar 9 is passed. Even if the thickness of the molten steel 4 is made thicker than the desired thickness, the thickness of the slab 6 can be set to a desired thickness when the rolls 8 and 8 are subsequently passed. Thus, since all the molten steel 4 continuously supplied to the dummy bar 9 can be cast into the slab 6 having a desired thickness, a decrease in the yield of the slab 6 can be suppressed.

  Moreover, since the short side walls 12 and 12 can move to a predetermined position in a state where the long side wall movable portion 22 is accommodated in the hollow portion 21, the degree of freedom of the width of the cast piece 6 that can be cast can be increased.

  In the embodiment described above, the immersion nozzle 5 itself is movable in the thickness direction of the mold 3 by the immersion nozzle position adjusting sliding plate 30, the flow rate adjusting sliding plate 31, and the fixed plate 32. FIG. Thus, the immersion nozzle 5 may be fixed to the tundish 2 and the tundish 2 may be moved together with the immersion nozzle 5. In such a case, the tundish 2 is provided with a moving mechanism 60 for moving the tundish 2 in the thickness direction of the mold 3. For the moving mechanism 60, for example, an actuator is used. And when inserting a dummy bar in the casting_mold | template 3, while moving the long side wall movable part 22 to the immersion nozzle 5 side, it arrange | positions the immersion nozzle 5 in the center of the thickness direction of the casting_mold | template 3 in planar view. Thereafter, after the dummy bar has passed through the mold 3, the long side wall movable portion 22 is moved to the electromagnetic stirrer 20 side in a state where the molten steel 4 is continuously supplied into the mold 3 to the concave portion 21. While accommodating, the tundish 2 is moved to the long side wall movable part 22 side, and the immersion nozzle 5 is arrange | positioned in the center of the thickness direction of the casting_mold | template 3 in planar view. Thereafter, the pair of short side walls 12, 12 are moved to a predetermined position. Also in the present embodiment, the immersion nozzle 5 can be moved in the thickness direction of the mold 3 with the movement of the long side wall movable portion 22, so that the immersion nozzle 5 can also be arranged at the center in the mold 3. Thereby, the region 51 between the long side wall movable part 22 and the immersion nozzle 5 and the region 51 between the long side wall 11 and the immersion nozzle 5 can be uniformly widened, and the swirl flowing through these regions 51 A sufficient flow path of the flow 50 can be secured.

  In the above embodiment, the hollow part 21, the long side wall movable part 22 and the moving mechanism 23 are provided only on one long side wall 10. However, as shown in FIG. 11 may be provided respectively. In addition, the structure of the hollow part 21, the long side wall movable part 22, and the moving mechanism 23 provided in the long side wall 11 is the structure of the hollow part 21, long side wall movable part 22, and the moving mechanism 23 of the long side wall 10 mentioned above. Since it is the same as that of FIG. In this case, since the freedom degree of the distance between the long side wall movable parts 22 and 22 becomes still larger, the area | region 51 between the long side wall movable part 22 and the immersion nozzle 5 can be enlarged more reliably. Therefore, it is possible to reliably prevent the inclusions 44 in the upper part in the mold 3 from being captured by the solidified shell 42 on the side surface of the mold 3, and the quality of the cast slab 6 to be cast can be further improved.

  In addition, although the electromagnetic stirring apparatuses 20 and 20 of the above embodiment were each provided in the long side walls 10 and 11, you may provide in the outer side of the long side walls 10 and 11, respectively. Moreover, it is good also as a structure where the long side wall movable part 22 and the electromagnetic stirring apparatus 20 were united so that it can move synchronizing with the long side wall movable part 22, for example.

  The present invention is useful when producing molten slab by supplying molten steel into a mold.

DESCRIPTION OF SYMBOLS 1 Continuous casting apparatus 2 Tundish 3 Mold 4 Molten steel 5 Immersion nozzle 6 Cast piece 7 Roll group 8 Rolling roll 9 Dummy bar 10, 11 Long side wall 10a, 11a Outer side surface 10b Inner side surface 12 Short side wall 20 Electromagnetic stirrer 21 Recessed part DESCRIPTION OF SYMBOLS 22 Long side wall movable part 23 Movement mechanism 24 Movement mechanism 30 Sliding plate 30a through-hole position adjustment sliding hole 31 Sliding plate 31 for flow rate adjustment 31a Through-hole 32 Fixed plate 32a Through-hole 40 Discharge hole 41 Discharge flow 42 Solidified shell 43 Upflow 44 Inclusion 45 Meniscus 46 Molten Powder 50 Swirl 51 Region 60 Movement Mechanism

Claims (6)

A continuous casting apparatus for steel,
A mold for casting molten steel having a pair of long side walls and a pair of short side walls;
An immersion nozzle for discharging molten steel into the mold,
An electromagnetic stirrer disposed along the outer surface of the pair of long side walls and stirring the molten steel in the upper part of the mold, and
At least one of the long side walls has a recess that is recessed from an inner surface to an outer surface at a position that faces at least the immersion nozzle, a shape that fits the recess, and moves in the thickness direction of the mold. With free long side wall movable part,
The pair of short side walls are respectively configured to be movable in the width direction of the mold when the long side wall movable part is accommodated in the hollow part. The recess and the long side wall movable part are provided only on the one long side wall,
The continuous casting apparatus for steel according to claim 1, wherein the immersion nozzle is configured to be movable in a thickness direction of the mold. The recess and the long side wall movable part are provided only on the one long side wall,
The immersion nozzle is connected to a tundish;
The continuous casting apparatus for steel according to claim 1, wherein the tundish is configured to be movable in the thickness direction of the mold together with the immersion nozzle. A continuous casting method using the continuous casting apparatus for steel according to any one of claims 1 to 3,
When inserting a dummy bar into the mold, move the long side wall movable part to the immersion nozzle side and place it,
After the dummy bar passes through the mold, the molten steel is continuously supplied to the dummy bar, and the long side wall movable part is moved to the electromagnetic stirrer side to be accommodated in the hollow part. The continuous casting method of steel, wherein the short side wall is moved to a predetermined position. A continuous casting method using the continuous casting apparatus for steel according to claim 2,
When inserting the dummy bar into the mold, the long side wall movable part is moved to the immersion nozzle side and arranged, and the immersion nozzle is arranged in the center in the thickness direction of the mold in plan view,
After the dummy bar passes through the mold, the long side wall movable part is moved to the electromagnetic stirrer side in a state in which molten steel is continuously supplied into the mold in the dummy bar, and accommodated in the recess part, The immersion nozzle is moved to the long side wall movable part side and arranged in the center in the thickness direction of the mold in plan view, and then the short side wall is moved to a predetermined position. Continuous casting method. A continuous casting method using the continuous casting apparatus for steel according to claim 3,
When inserting the dummy bar into the mold, the long side wall movable part is moved to the immersion nozzle side and arranged, and the immersion nozzle is arranged in the center in the thickness direction of the mold in plan view,
After the dummy bar passes through the mold, the long side wall movable part is moved to the electromagnetic stirrer side in a state in which molten steel is continuously supplied into the mold in the dummy bar, and accommodated in the recess part, Move the tundish to the long side wall movable part side,
A continuous casting method of steel, wherein the immersion nozzle is arranged in the center in the thickness direction of the mold in plan view, and then the short side wall is moved to a predetermined position.

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