KR20190066330A - Continuous casting method and apparatus - Google Patents

Abstract

The present invention relates to a continuous casting method and a continuous casting apparatus formed to perform the method which comprises the following processes of: controlling previous molten steel to be discharged while moving a weir arranged in a supply area in a tundish to a discharge area at the end of a previous process using previous molten steel; starting to supply following molten steel to the supply area; and a performing a following process using the following molten steel. Provided are the continuous casting method and the apparatus, which can effectively reduce a mixing amount of the previous molten steel and the following molten steel.

Description

TECHNICAL FIELD [0001] The present invention relates to a continuous casting method and apparatus,

TECHNICAL FIELD The present invention relates to a continuous casting method and apparatus, and more particularly, to a continuous casting method and apparatus capable of reducing the mixture of previous molten steel and subsequent molten steel.

The continuous casting facility includes a ladle for conveying molten steel, a tundish for temporary storage of molten steel in ladle, a mold for solidifying the molten steel of the tundish with the molten steel, a casting continuously drawn from the mold, As shown in FIG. Among them, the tundish serves to keep the molten steel level constant and to control the molten steel flow in the mold to a steady state.

At the beginning and end of the continuous casting process, the molten steel level is lowered and the influence thereof can be extended to the molten steel flow in the mold. Therefore, the quality of the head portion and the tail portion of the cast steel is poor. In addition, a crop occurs in the head part and the tail part, and the shape is not straight. For this reason, the head part and the tail part of the main body do not satisfy the specifications desired by the customer, so most of them are scrapped.

There is a problem in that the amount of steel produced in the continuous casting process is reduced as the head portion and the tail portion of the cast steel are scrapped. In order to overcome this problem, that is, in order to increase the production of crude steel by reducing the amount of head and tail portions of cast steel, most of continuous casting process is to continuously supply molten steel to turn- Lt; / RTI >

However, when the continuous casting process is performed in the continuous casting mode, if the steel species of the previous molten steel and the succeeding molten steel are different, the mixed portion occurs in the casting at a predetermined point after replacing the ladle. Here, the mixing portion refers to a portion cast into a cast with the former molten steel mixed with the succeeding molten steel. Since the mixed portion is scrapped, the continuous casting process of the continuous casting type still has a problem of reducing the production amount of crude steel.

Techniques as a background of the present invention are listed in the following patent documents.

KR 10-1485913 B1

The present invention provides a continuous casting method and apparatus capable of effectively reducing the amount of mixture of previous molten steel and subsequent molten steel.

The continuous casting method according to the embodiment of the present invention is a continuous casting method capable of reducing the mixture of previous molten steel and subsequent molten steel, wherein, at the end of the previous process using previous molten steel, To control the discharge of the molten steel; Initiating supply of subsequent molten steel to the supply region; And a subsequent process using subsequent molten steel.

And stopping the weir in a boundary region between the supply region and the discharge region.

After the weir is stopped, the supply of the next molten steel may be started.

And returning the weir from the border area to the supply area.

During the process of returning the weir, the process of starting supply of the subsequent molten steel may be performed.

After the process of returning the weir, the process of starting supply of the subsequent molten steel may be performed.

The previous molten steel and the succeeding molten steel may have different steel types.

The process of controlling the discharge of the previous molten steel may include: a process of pushing the previous molten steel using the weir; And moving the previous molten steel to the discharge region through a residual hole formed in the dam disposed in the boundary region.

The step of stopping the weir in the boundary region may include stopping the weir in the vicinity of the dam disposed in the boundary region.

A continuous casting apparatus according to an embodiment of the present invention is a continuous casting apparatus capable of reducing a mixture of a previous molten steel and a succeeding molten steel, comprising: a turn-dish having a bottom opening; A weir spaced from the bottom and contacting both sidewalls of the tundish; A driving unit movably supporting the weir; And a control unit for controlling the driving unit by determining the moving direction and the moving direction of the weir according to the timing of the process.

The control unit may control the driving unit to move the weir to the lubrication port side at the end of the previous process using the previous molten steel.

The control unit may control the drive unit to stop the weir at the start of supply of the subsequent molten steel.

The control unit may control the driving unit to return the weir at the start of supply of the subsequent molten steel.

The control unit may control the drive unit to return the weir before the start of supply of the next molten steel.

Further comprising: a dam disposed at the bottom of the turn-off port and connecting the both side walls, wherein the weir is disposed on the opposite side of the dam from the dam, Direction and whether it is controlled and the flow of molten steel can be controlled.

According to the embodiment of the present invention, after the discharge of the previous molten steel is controlled by moving the weir in the turn dice at the end of the previous process using the previous molten steel, the subsequent molten steel can be injected into the turndish and the subsequent process can be performed. Thus, the mixing of the previous molten steel and the succeeding molten steel can be reduced.

Further, according to the embodiment of the present invention, it is possible to control the flow direction of the subsequent molten steel injected into the turn-off by controlling the movement direction and the movement of the weir during the injection of the subsequent molten steel. Therefore, mixing of the previous molten steel and the succeeding molten steel can be further reduced.

For example, when the present invention is applied to a continuous casting process of continuous casting using continuous casting using different types of molten steel, the weir is moved to the side of the casting die at the end of the continuous casting process using the previous casting steel, After pushing, the subsequent molten steel may be injected in the turn-off, and the continuous structure process using the subsequent molten steel may be performed. At this time, during the injection of the next molten steel, it is possible to control the movement of the weir and the moving direction in various ways, and to reduce the mixing of the previous molten steel and the subsequent molten steel. Therefore, it is possible to reduce the occurrence of the mixing portion in the cast steel and to improve the productivity.

On the other hand, according to the embodiment of the present invention, the weir is horizontally moved and controls the flow of the previous molten steel and the subsequent molten steel. Thus, the interior of the turn-off is not locally divided or isolated, and the molten steel flow in the turn-off can be continuous without interruption. Thus, the continuous casting process can be smoothly performed.

1 and 2 are schematic views of a continuous casting apparatus according to an embodiment of the present invention.
3 is a process diagram illustrating a continuous casting method according to an embodiment of the present invention in comparison with a comparative example.
FIG. 4 is a view showing a simulation result of mixing behavior of molten steel according to an embodiment of the present invention, in comparison with a comparative example.
FIG. 5 is a graph illustrating an example of non-dimensional mixed concentration values obtained in a continuous casting process according to an embodiment of the present invention, in comparison with a comparative example.
FIG. 6 is a comparison table of values of the gypsum mixing time derived in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described below, but may be embodied in various forms. It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The drawings may be exaggerated for purposes of describing embodiments of the present invention, wherein like reference numerals refer to like elements throughout.

The continuous casting method and apparatus according to the embodiment of the present invention provides a technical feature capable of reducing the mixture of the previous molten steel and the succeeding molten steel.

The continuous casting method and apparatus according to an embodiment of the present invention may be applied to various casting processes using various melts. Hereinafter, embodiments of the present invention will be described with reference to the continuous casting process of the present invention.

1 is a schematic view of a continuous casting apparatus according to an embodiment of the present invention. 2 (a) and 2 (b) are schematic views showing a main portion of a continuous casting apparatus according to an embodiment of the present invention.

A continuous casting apparatus according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. The continuous casting apparatus according to the embodiment of the present invention is a continuous casting apparatus for a continuous casting process of the present invention. The continuous casting apparatus includes a tundish 30 in which a runner 35 is formed at a bottom 33, A weir 63 contacting the both sidewalls 34b of the dice 30 and a driving unit 70 movably supporting the weir 63. Whether or not the moving direction of the weir 63 and the movement of the weir 63 are determined And a control unit (80) for controlling the driving unit (70). The continuous casting apparatus may further include a ladle 10, a shroud nozzle 20, a dam 61, a dipping nozzle 40, a mold 50, and a cooling zone (not shown). The continuous casting apparatus can continuously cast the slab S by replacing the ladle 10 and supplying the subsequent molten steel different in grade from the previous molten steel to the turn-dish 30 containing the previous molten steel.

Here, the previous molten steel may refer to molten steel currently being processed in the turn-dish 30, and the subsequent molten steel may refer to a new molten steel to be supplied to the turndisse 30 (also referred to as "injected "). Previous and subsequent molten steel may have different steel grades.

The ladle 10 is a cylindrical container for conveying molten steel M, the outer surface of which is formed of iron and the inner surface of which is constructed of refractory. The ladle 10 is disposed above the turn-dish 30, is seated in a ladle turret (not shown), and is carried by a crane (not shown). The ladle 10 can carry the molten steel M and can supply the molten steel M to the turndish 30.

The shroud nozzle 20 is mounted on the lower portion of the ladle 10 and can supply molten steel M contained in the ladle 10 to the turn-dish 30. The shroud nozzle 20 may be disposed at the bottom of the turn-dish 30. The shroud nozzle 20 may be supported by a manipulator (not shown).

The turn-dish 30 temporarily stores the molten steel M and can supply the molten steel M to the mold 50. The turn-dish 30 is disposed so as to surround the lower portion of the shroud nozzle 20 on the lower side of the ladle 10. The outer surface of the turn dish 30 is formed of iron, and the inner surface of the turn surface 30 is formed of refractory. The turn-dish 30 may have a shape that is horizontally symmetrical in the longitudinal direction (x), and the width in the longitudinal direction may be larger than the width in the width direction (y). The turn-dish 30 may have a shape in which the central portion in the longitudinal direction protrudes to one side in the width direction. The shroud nozzle 20 may be disposed on the center portion of the turn-dish 30 in the longitudinal direction. A space for taking molten steel M may be formed in the turn-dish 30, and a louver 35 may be formed in the bottom 33. The lances 35 can penetrate the bottom 33 at angularly spaced positions on both sides in the longitudinal direction. The louvers 35 may be located in the vicinity of both side walls 34a extending in the width direction of the turn-dish 30.

The immersion nozzle 40 is disposed below the turn-dish 30 and can be mounted on the louver 35. The immersion nozzle 40 is a hollow tube formed of refractory material for passing the molten steel M and extends in the height direction z. A slide gate (not shown) is provided between the immersion nozzle 40 and the louver 35 so as to adjust the amount of molten steel to be introduced. The molten steel M in the turn-dish 30 can be supplied to the mold 50 through the immersion nozzle 30. [

The mold 50 is disposed so as to surround the lower portion of the immersion nozzle 40 and can be supplied with molten steel M and solidify into the slab S. The mold 50 may be formed in a rectangular or square shape, the inside thereof may penetrate in the height direction, and the upper and lower portions may be opened.

The cooling bases are arranged on the lower side of the mold 50 in the casting direction to form a drawing path of the slab S. The cooling stand can cool and press down the casting S continuously withdrawn from the mold 50, and can perform a series of molding operations. The cooling bed may include segments. The segments may be provided with rollers for drawing of the cast S and cooling water nozzles for cooling the cast S. The slab S having passed through the cooling stand is cut at a cut portion (not shown) and can be fed to a rolling facility.

Hereinafter, a dam unit 60 according to an embodiment of the present invention will be described. The dam unit (60) is installed inside the turn-dish (30) and can control the flow of molten steel (M). The dam units 60 may be installed at symmetrical positions on both sides in the longitudinal direction.

The dam unit 60 includes a dam 61 and a weir 62 made of refractory material. The dam 61 is provided on the floor 33 so as to be spaced apart from the center of the longitudinal direction of the turn-dish 30 in the louver 35 and extends in the width direction so as to connect the both side walls 34b extending in the longitudinal direction. . The dam 61 is located at a lower portion of the turn-dish 30 and may be formed through the lower portion of the dam 61 to form a dwelling hole 62. Molten steel M can enter and exit into both sides of the dam 61 in the longitudinal direction through the dwelling hole 62.

The interior of the turn-dish 30 can be divided into the supply region A and the discharge region B with the dam 61 as the center. At this time, the region where the dam 61 is provided is referred to as a boundary region C between the supply region A and the discharge region B. [ The supply region A is an area located inside the dam 61 and is an area in which the shroud nozzle 20 is disposed. When the molten steel M is supplied into the turn-dish 30, . The discharge region B is an area located outside the dams 61 and is a region in which the louver 35 is located and is the area through which the molten steel M supplied to the inside of the turn dish 30 last passes , And the molten steel (M) is discharged to the discharge port (35).

The boundary region C is an open space provided to connect the discharge region B and the supply region A. The discharge region B and the supply region A are connected to each other through the remaining space 62 and the upper space of the dam 61, A) is always connected. The molten steel M between the supply region A and the discharge region B can be taken in and out through the boundary region C.

The weir 63 is disposed on the opposite side of the ramp 35 about the dam 61 and spaced apart from the bottom 33 and extending in the width direction and having both side walls 34b ). ≪ / RTI > The weir 63 controls the flow direction and the direction of the molten steel M in the supply region A according to the timing of the briquette continuous casting process. The weir 63 is movable in the longitudinal direction and, for this purpose, it can be supported by the driving unit 70. Weir 63 may also be referred to as a moving weir. Hereinafter, the "moving direction and whether or not the weir 63" is collectively referred to as "movement ".

The driving unit 70 is capable of movably supporting the weir 63. The driving unit 70 may be, for example, a mechanical or hydraulic type driving unit provided outside the turn-dish 30. The driving unit 70 supports the weir 63 and can be moved in the longitudinal direction. The driving unit 70 has various structures for moving the weir 63, and it is not particularly limited. One example of the driving unit 70 will be described. The driving unit 70 includes a first driving rod 71 extending in the height direction and disposed on the upper side of the weir 63 and mounted on the upper end of the weir 63, A third driving rod 73 to which the second driving rod 72 is supported and a third driving rod 73 that extends in the longitudinal direction and on which the third driving rod 72 is mounted, And a fourth drive rod 74 for moving the drive rod 73 in the longitudinal direction. In addition, the configuration of the driving unit 70 may be various.

The control unit 80 can control the driving unit 70 by determining the moving direction and the movement of the weir 63 according to the timing of the continuous casting process. Here, the moving direction includes the direction from the supply region A to the discharge region B and the opposite direction. The direction from the supply region A to the discharge region B is referred to as one direction and the direction opposite to the one direction is referred to as the other direction. Movement includes move and stop. The control unit 80 controls the weir 63 through the driving unit 70. The control unit 80 controls the movement of the weir 63 in one direction, the return of the weir 63 in the other direction, It can be divided into branches. Of course, its control point can be determined according to the timing of the continuous casting process.

The control unit 80 controls the drive unit 70 to move the weir 63 in the supply region A toward the lubrication port 35 at the end of the previous continuous casting process using the previous molten steel Can be controlled.

The control unit 80 controls the drive unit 70 to stop the weir 63 near the boundary region C at the start of the supply of the subsequent molten steel or controls the drive unit 70 to start the weir To control the driving unit 70 to return the weir 63 to the correct position in the supply area A or to return the weir 63 to the correct position in the supply area A before starting the supply of the subsequent molten steel The driving unit 70 can be controlled.

 Here, in the last stage of the previous process, when the molten steel to be supplied to the previous molten steel being currently processed in the turn-dish 30 and the molten steel to be supplied subsequently to the turn-dish 30 are different from each other, To the time before the supply of the subsequent molten steel is started in the turn-dish 30. Of course, the end of the previous process can be defined in various other ways. For example, the period during which the molten steel is changed from one point in time to the completion of the previous process and before the next process is started is referred to as the end of the previous process.

Also, the correct position may refer to the position of the initial or middle weir 63 excluding the end of the previous process. That is, the position of the weir 63 when the normal continuous casting operation is performed using molten steel is referred to as a straightening operation except for the time of replacing the steel type.

The control of the control unit 80 and the operation of the driving unit 70 enable the cast steel S to be fed to the cast steel S at the starting point of the subsequent continuous casting process using the subsequent cast steel in the continuous casting step It is possible to reduce occurrence of the mixing portion of molten steel. That is, the control unit 80, the driving unit 70, and the weir 63 may be constructed to be newly added to the continuous casting apparatus in order to reduce the mixing amount of the bridges.

3 is a process diagram illustrating a continuous casting method according to an embodiment of the present invention in comparison with a comparative example. FIG. 3 (a) is a process chart of a continuous casting method according to a comparative example, FIG. 3 (b) is a process chart of a continuous casting method according to a first embodiment of the present invention, Fig. 3 is a process diagram of a continuous casting method according to a second embodiment of the present invention. 3 (d) is a process diagram of the continuous casting method according to the third embodiment of the present invention.

Referring to Figs. 1, 2, and 3 (b) to 3 (d), a continuous casting method according to an embodiment of the present invention will be described. Explain in contrast.

Herein, the contents overlapping with the description of the continuous casting apparatus of the embodiment of the present invention will be omitted or briefly described below. In addition, the embodiment will be described with reference to a side of one side of the turn-dish 30, for example, the left side of Figs. 1 and 2, in which the turn-dish 30 is symmetrical in the longitudinal direction.

The continuous casting method according to an embodiment of the present invention is a continuous casting method having a weir operation method for reducing the amount of mixing in a continuous casting step in a continuous casting process. In the end of a previous casting process using a previous casting steel, The process of moving the weir 63 disposed in the supply region A toward the discharge region B and controlling the discharge of the molten steel beforehand is performed in the boundary region C between the supply region A and the discharge region B, A process of stopping the supply of the molten steel 63, a process of starting supply of the subsequent molten steel to the supply region A, and a process of performing a subsequent process using the subsequent molten steel. At this time, the previous molten steel and the succeeding molten steel have different steel types.

First, a continuous casting apparatus according to an embodiment of the present invention is provided, and a continuous casting process, that is, a previous process is performed using a previous molten steel in a continuous casting apparatus. For example, the ladle 10 containing the previous molten steel is provided on the upper side of the turn-dish 30, the previous molten steel is supplied to the turndisse 30, the previous molten steel in the turndish 30 is supplied to the mold 50, (S) is continuously cast. At this time, it is possible to supply the previous molten steel to the turn-dish 30 a predetermined number of times while exchanging the ladle 10, so that the level of the molten steel in the turn-dish 30 can be maintained at the steady state level.

Subsequently, at the end of the previous process using the previous molten steel, the weir 63 disposed in the supply region A in the turn-dish 30 is moved to the discharge region B side to control the discharge of the previous molten steel. This corresponds to the step marked "1" in the figures of FIGS. 3 (b) to 3 (d).

The process of controlling the discharge of the molten steel is a process of reducing the mixing of the molten steel by controlling the discharge of the molten steel remaining in the turn dish 30 by moving the weir 63 in the longitudinal direction, The process of moving the previous molten steel to the discharge region B through the process of pushing the previous molten steel from the supply region A and the remnant hole 62 formed in the dam 61 disposed in the boundary region C . At this time, the previous molten steel may overflow the upper portion of the dam 61 and move to the discharge region B depending on the level. In this process, the weir 63 can move to the boundary region C where the dam 61 is installed. At this time, the weir 63 can move to a predetermined position in the vicinity of the dam 61 separated from the dam 61.

Thereafter, the weir 63 is stopped in the boundary region C. At this time, the weir 63 can be stopped in the vicinity of the dam 61 disposed in the boundary region C. Thereafter, the supply of the subsequent molten steel to the supply region A is started, the subsequent process using the subsequent molten steel is carried out, and the molten steel is continuously cast into the succeeding molten steel.

At this time, in the process of starting the supply of the subsequent molten steel to the supplying region A, the amount of the molten steel to be mixed may vary according to the movement of the weir 63 and the subsequent supply method of the molten steel. Embodiments thereof will be described below, and the movement of the weir 63 and the manner of supplying the subsequent molten steel to minimize the mixing amount of the bridges will be described.

First Embodiment

After the weir 63 is stopped in the boundary region C, the process of starting the supply of the subsequent molten steel is performed. This corresponds to step "2 " shown in Fig. 3 (b).

This pushes out the previous molten steel in the turn dish 30 while the weir 63 in the correct position (also called the "initial position") moves in one direction before the subsequent molten steel is supplied to the turn disc 30, The supply of the subsequent molten steel to the supply region A is started after the weir 63 is pushed to the discharge region B as much as possible. At this time, it can be said that the supply method is such that the following molten steel flows freely in one direction in the supply region (A). On the other hand, the return of the weir 63 can be performed after the level of the subsequent molten steel has increased to a predetermined level or after the level of the subsequent molten steel has reached the level of the steady state.

Second Embodiment

After the process of stopping the weir 63 in the boundary region C, the process of starting the supply of the subsequent molten steel is carried out, and between the process of stopping the weir 63 and the start of the supply of the subsequent molten steel, And returning the weir 63 from the region C to the supply region A. At this time, during the process of returning the weir 63, the process of starting the supply of the subsequent molten steel is performed. This corresponds to the "2", "3" and "4" steps in FIG. 3 (c).

That is, the weir 63 is stopped, and at this time supply of the subsequent molten steel is started (step "2"). At the same time, when the next molten steel is supplied to the supply region A, the weir 63 is returned from the boundary region C to the supply region A (step "3 ") and the weir 63 reaches the correct position The movement of the weir 63 is stopped and the supply of the subsequent molten steel is continued.

For example, when the weft 63 is moved in one direction before the subsequent molten steel is injected into the turn-dish 30, the remaining molten steel remaining in the turndish 30 is pushed out and the movement is finished. Subsequent molten steel is supplied, During the feeding, the weir 63 is returned to the other direction and the movement is terminated at the predetermined position. At this time, the flow of molten steel in the supply region A can be controlled by the weir 63 returning to the other direction. This is a feeding method in which the weir 63 is used to actively regulate the subsequent molten steel flow in the supplying region A. [

Third Embodiment

After the process of stopping the weir 63 in the boundary region C, the process of starting the supply of the subsequent molten steel is carried out, and between the process of stopping the weir 63 and the start of the supply of the subsequent molten steel, Further comprising the step of returning the weir 63 from the region C to the supply region A. The process of returning the weir 63 is followed by the start of the supply of the subsequent molten steel. For example, in the third embodiment, the movements of the weir 63 are the same as those of the second embodiment, but the supply start time of the subsequent molten steel is determined after the return of the weir 63. This corresponds to the steps "2 "," 3 ", and "4"

The method of supplying the subsequent molten steel to the supplying region A after the movement of the weir 63 in the other direction and returning to the normal position is completed is a method of controlling the flow of the succeeding molten steel in the supplying region A, As a method of controlling the flow by using the weir 63 stopping at the correct position, the difference from the second embodiment is that the weir 63 is used to manually adjust the subsequent molten steel flow.

3 (b) to 3 (d) denote the moving speed of the weir 63, and the range may be 0.02 to 0.2 m / s. This speed can be determined in consideration of the casting speed in the casting mold 50, the amount of remaining molten steel, and the like.

As described above, by controlling the movement of the weir 63, the discharge method of the previous molten steel and the supply method of the subsequent molten steel, the molten steel mixed amount of the molten steel can be reduced and the amount of the mixed molten steel can be minimized Method can be derived.

3 (a) is a process diagram of a continuous casting method according to a comparative example. In the process of the comparative example, when the molten steel is supplied from the shroud nozzle 2 to the turn-dish 2, the weir B is fixed, The continuous casting process is carried out without control on the previous molten steel and the subsequent molten steel in the dies 3. That is, as in the prior art, in the comparative example, before the supply of the subsequent molten steel to the supply region A is started, the discharge of the molten steel remaining in the turn-dish 30 is not controlled, It does not control the movement of the weir 63 and the manner of supplying the subsequent molten steel in the process of starting the supply. On the other hand, reference numeral 4 denotes an immersion nozzle, and 6A denotes a dam.

Hereinafter, the movement of the weir 63 and the manner of supplying the subsequent molten steel to minimize the mixing amount of the gravel type will be described with reference to FIG. FIG. 4 is a view showing a simulation result of mixing behavior of molten steel according to an embodiment of the present invention, in comparison with a comparative example. 4 (a), 4 (b), 4 (c) and 4 (d) are simulation results corresponding to FIGS. 3 (a), 3 (b), 3 (c) and 3 (d).

4 (a), 4 (b), 4 (c) and 4 (d) show the mixing behavior of the molten steel in four different operating modes of the weir 63, according to the comparative example and the embodiments. Since this simulation can be obtained through various known flow analysis programs, the description of the simulation process is omitted here.

At the end of the previous process, previous molten steel, slag, and air remain in the interior of the turn-dish, and when the previous molten steel height is at the same height as the end of the shroud nozzle, the shroud nozzle And only the molten steel concentration (subsequent steel species concentration) of the subsequent molten steel in the tundish was shown. Here, the closer to the red color is, the higher the molten steel concentration of the subsequent molten steel is, and the subsequent molten steel remains pure without being contaminated by the previous molten steel.

(A) showing the simulation of the comparative example with 10 seconds after the subsequent molten steel flows into the tundish, in the comparative example, the succeeding steel species penetrates most quickly in the direction of the discharge. On the other hand, in the case of (d) showing the simulation according to the third embodiment, the succeeding molten steel is concentrated in the vicinity of the shroud nozzle of the supply region in a state where 10 seconds have elapsed after the subsequent molten steel has flowed into the turn-off time Can be seen. This seems to be due to the fact that the weir has moved to the correct position after the previous molten steel has been pushed out. In addition, simulation results of the first and second embodiments show similar behaviors as those of the simulation results of the third embodiment, and it can be seen that the subsequent molten steel is concentrated in the vicinity of the shroud nozzle of the supply region.

After about 40 seconds have elapsed since the subsequent molten steel flowed into the tundish, the molten steel concentration in the discharge area can be seen. (a) to (d), the mixing concentration near the outlet of the discharge region is the lowest in (c) corresponding to the simulation of the second embodiment. Here, the closer the value of the succeeding steel species to 1, the closer the value of the mixed concentration becomes to zero. That is, the simulation result of the second embodiment indicates that the concentration of the subsequent molten steel in the discharge region is the largest, which means that the amount of the subsequent molten steel and the previous molten steel in the discharge region is the smallest.

In the case of (a) and (b), that is, in the case of the comparative example and the first embodiment, the subsequent molten steel is discharged into the lubrication port after about 170 seconds since the subsequent molten steel flows into the tundish, It can be seen that the mixing of the previous molten steel and the previous molten steel still continues in the vicinity of the shroud nozzle of the supply region. Of course, the mixing degree of the first embodiment is less than that of the comparative example. On the other hand, in the case of (c) and (d), that is, in the case of the second and third embodiments, it can be seen that the thickened concentration of the subsequent molten steel flows along the entire region of the turn-off. On the other hand, the first embodiment exhibits a slightly different mixing ratio in the supply region, but shows a subsequent molten steel with a thick concentration in the vicinity of the discharge region. Therefore, the first embodiment has a clear difference from the comparative example, It can be seen that the present invention corresponds to the third embodiment.

As a result, it can be seen that the simulation result (c) of the second embodiment shows the best result in reducing the mixture amount of the gaseous mixture, and the method of the second embodiment is most advantageous.

FIG. 5 is a graph illustrating an example of non-dimensional mixed concentration values obtained in a continuous casting process according to an embodiment of the present invention, in comparison with a comparative example. 5 (a) to 5 (d) correspond one-to-one to FIGS. 4 (a) to 4 (d) in order.

FIG. 5 shows a graph of a non-dimensional mixed concentration in a range of 0 to 1 with respect to time in the discharge region, where 0 represents the previous molten steel and 1 represents the subsequent molten steel. When the mixing interval is assumed to be in the range of 0.1 to 0.9 in the dimensionless range according to the allowable range of components according to the steel types of the molten steel, the graph of (c) according to the second embodiment shows that the holding time of the mixing interval is the shortest have.

On the other hand, since the product of the mixing time, the casting area, the casting speed and the molten steel density represents the mixing amount, it can be seen that the case (c) having the shortest mixing time is the most advantageous in reducing the mixing ratio of the gypsum.

FIG. 6 is a comparison table of values of the gypsum mixing time derived in FIG. That is, FIG. 6 shows the gypsum mixing time according to each example and the comparative example obtained in the graph of the dimensionless mixing concentration in FIG. 5, and based on the mixing time according to the comparative example (a) In the examples, it is possible to reduce the mixture amount of the gypsum by 14 to 57%, and in particular, the second embodiment (c) has the reduction effect of 57% as compared with the conventional example.

According to the embodiment of the present invention, by moving the weir 63 according to the timing of the process, it is possible to reduce the blending amount by 14 to 57%. At this time, the moving speed of the weir 63 is in the range of 0.02 to 0.2 m / s, and the moving direction of the weir 63 (also referred to as " 2 (c) and the third embodiment (d). In the case of the second embodiment (c), it can be seen that the most advantageous effect is obtained in reducing the mixture amount of the gaseous mixture.

As described above, the continuous casting method and apparatus according to the embodiment of the present invention are intended to reduce the mixing of molten steel of different components in the turn-dish 30 during the continuous casting process, for example, (Moving direction and direction) of the weir 63 and the supply time point of the subsequent molten steel are determined in order to minimize the mixing amount of the gaseous mixture based on the time when the molten mixture flows into the mixing chamber 30, , It is possible to reduce the mixing amount of gypsum by 14 to 57%.

The above-described embodiments of the present invention are for the explanation of the present invention and are not intended to limit the present invention. It should be noted that the configurations and the methods disclosed in the above embodiments of the present invention may be modified into various forms by combining or intersecting with each other, and such modifications may be considered within the scope of the present invention. That is, the present invention may be embodied in various forms within the scope of the claims and equivalents thereof, and it is possible for the technician skilled in the art to make various embodiments within the scope of the technical idea of the present invention. .

10: Ladle 30: Turn Dish
50: Mold 63: Weir
70: driving unit 80:

Claims (15)

As a continuous casting method,
Moving the weir disposed in the supply region in the tundish to the discharge region side and controlling the discharge of the previous molten steel at the end of the previous process using the previous molten steel;
Initiating supply of subsequent molten steel to the supply region;
And performing a subsequent process using subsequent molten steel. The method according to claim 1,
And stopping the weir in a boundary region between the supply region and the discharge region. The method of claim 2,
And starting the supply of the subsequent molten steel after the weir is stopped. The method of claim 2,
And returning the weir from the boundary region to the supply region. The method of claim 4,
And a step of starting supply of the subsequent molten steel during the course of returning the weir. The method of claim 4,
And a step of starting supply of the subsequent molten steel after the returning of the weir. The method according to claim 1,
Wherein the previous molten steel and the succeeding molten steel have different steel types. The method of claim 2,
The process of controlling the discharge of the molten steel includes:
Pushing the previous molten steel using the weir;
And moving the previous molten steel to the discharge region through a residual hole formed in the dam disposed in the boundary region. The method of claim 2,
And stopping the weir in the border area,
And stopping the weir in the vicinity of a dam disposed in the boundary region. As a continuous casting apparatus,
A turn-off with a lap on the floor;
A weir spaced from the bottom and contacting both sidewalls of the tundish;
A driving unit movably supporting the weir; And
And controlling the driving unit by determining the movement direction and the movement of the weir in accordance with a time point of the process. The method of claim 10,
Wherein,
And controls the drive unit to move the weir to the lubrication port side at the end of the previous process using the previous molten steel. The method of claim 11,
Wherein,
And controls the drive unit to stop the weir at the start of supply of the subsequent molten steel. The method of claim 11,
Wherein,
And controls the drive unit to return the weir at the start of supply of the subsequent molten steel. The method of claim 11,
Wherein,
And controls the driving unit to return the weir before the start of supply of the next molten steel. The method of claim 10,
Further comprising: a dam spaced apart from the ladder and installed at the bottom of the turn-dish and connecting the two side walls,
Wherein the weir is disposed on the opposite side of the damper about the dam, and the direction and the direction of movement are controlled according to the viewpoint, and the flow of the molten steel is controlled.

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