KR101862146B1 - Method for casting - Google Patents

Abstract

The present invention relates to a casting method. The present invention comprises: a process of injecting molten steel into a cast and solidifying the molten steel into a cast steel; a process of drawing and cooling the cast steel in the casting direction; and a process of controlling the casting speed of casting and a quantity of cooling water sprayed on the cast in accordance with an operation section by using each operation pattern established for each operation section. Further, when determining the casting speed of a cast tail unit at an end of the operation, duration of a low-speed unit is relatively increased in a last unit of an end of the operation by utilizing an end-of-operation pattern so that the molten steel flowing out from the tail unit at the end of casting can be prevented.

Description

{METHOD FOR CASTING}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method, and more particularly, to a casting method capable of preventing molten steel from leaking out of a cast iron part at the end of casting.

In the steelmaking sector, the continuous casting method has superior quality uniformity and error rate compared to the conventional roughing method. Accordingly, a lot of research and development has been carried out on the operation equipment and the operation technology of the continuous casting method. As a result, almost all kinds of steel including high alloy steel can be produced by continuous casting. In this continuous casting process, the casting speed and temperature are the main factors that determine the productivity and quality of cast steel.

The casting speed has a great influence on the breakout, bulging, bleeding and the like in the continuous casting operation and has a great influence on the surface flaws and internal cracks in the casting quality. Therefore, it is necessary to select an appropriate casting speed according to the steel grade, the casting size and the molten steel temperature. The temperature is related to the development of the shell. That is, if the temperature is too high, the development of the coagulation angle is delayed, and the risk of breakout increases.

Particularly, when casting the cast steel at the casting speed of 0.5 m / min, which is the casting speed of the general steel material at the end of casting the cast steel of the steel material, the silicon component in the casting frame is subcooled, do.

On the other hand, even if casting is performed at a casting speed of 1.0 m / min, which is the casting speed of the current steel sheet material at the end of casting, at the end of casting the cast steel of the electric steel sheet material, the cast tail portion is not solidified until it passes the # 5 to # 6 segments, Molten steel may leak out.

Techniques that constitute the background of the present invention are disclosed in the following patent documents.

KR 10-0122299 B1 JP 4592974 B2 KR 10-2012-0054436 A KR 10-2014-0058144 A KR 10-2011-0137863 A KR 10-0775089 B1

The present invention provides a casting method capable of preventing molten steel from leaking out of the cast iron part at the end of casting.

A casting method according to an embodiment of the present invention includes the steps of injecting molten steel into a mold and solidifying the molten steel into a cast steel; Drawing the cast steel in a casting direction and cooling it; And controlling the casting speed of the casting machine and the injection amount of the cooling water sprayed on the casting machine in accordance with each operation section using each operation pattern established for each operation section. When controlling the casting speed of the casting tail section at the end of the operation, Using the operation pattern, the maintenance time of the low speed section is relatively increased in the entire section of the end of the operation.

The entire duration of the end of the operation includes a low speed section, a speed change section and a subordinate section in the order of time elapsed. When the casting speed of the cast tail portion is controlled at the end of the operation, the holding time of the low speed section is increased , It is possible to reduce the holding time of the speed change section.

Wherein the speed change section includes at least one constant speed section that connects between a plurality of acceleration sections and acceleration sections or includes a first acceleration section, a constant speed section and a second acceleration section in accordance with the progress of the operation, The casting acceleration is the same, and when the casting speed of the cast tail portion is controlled at the end of the operation, the holding time of the constant velocity section can be reduced after increasing the holding time of the low speed section.

When the casting speed of the cast tail portion is controlled at the end of the operation, the maintenance time of the low speed section may be increased to 2 min to 3 min and the maintenance time of the other section may be reduced.

When controlling the casting speed of the cast tail portion at the end of the operation, the casting speed of the low-speed section can be controlled to 0.8 m / min or more.

When the casting speed of the cast tail portion is controlled at the end of the operation, the casting speed of the slave portion can be controlled to 1.7 m / min in the last section of the operation end.

The casting speed, the casting acceleration and the holding time information at the end of the work, the casting speed, the casting acceleration and the holding time information at the end of the work, It can be determined according to the code.

When the injection amount of the cooling water injected to the cast steel frame is controlled at the end of the operation, the injection amount of the cooling water injected to the cast steel frame part can be different for each position of the cast steel tail part by utilizing the last operation pattern.

The bender and the plurality of segments are disposed on the lower side of the mold along the casting direction to perform drawing and cooling of the cast steel and to control the injection amount of the cooling water injected to the cast steel frame at the end of the casting operation, It is possible to control the injection amount of the cooling water injected to the spindle frame at the position of the nearest work segment to be larger than the injection amount of the cooling water injected to the spindle stem at another position.

The injection quantity of the cooling water injected to the long side of the spiral tail portion and the injection quantity of the cooling water injected to the short side of the spindle tail portion in the bender and the one segment can be controlled differently when the injection amount of the cooling water injected to the cast steel frame is controlled at the end of the operation .

The injection amount of the cooling water in the bender and the one segment is controlled to be 50 to 300 L / min and the injection time of the cooling water can be controlled to be 2 to 30 sec to 4 min have.

The spray amount of the cooling water sprayed to the long side of the spout tail portion in the bender and the one segment may be set to 100 to 300 L / min, and the spray amount of the cooling water sprayed to the short side may be set to 50 to 150 L / min.

The end-of-operation pattern may further include information on the amount of injection of cooling water for each position of the casting tail portion. The molten steel may have a strong operation code, and the injection amount information of the cooling water for each position of the cast tail portion of the end- have.

The molten steel may include molten steel for casting an electric steel sheet material or a wider material.

According to the embodiment of the present invention, it is possible to sufficiently cool the cast tail portion before entering the predetermined section in which the cast tail portion touches the segment roll at an angle of 45 degrees by relatively increasing the holding time of the low-speed section at the end of casting.

Further, it is possible to sufficiently cool the cast tail portion by increasing the injection amount of the cooling water injected to the cast steel frame portion in the low speed section at the end of the casting, and the cast tail portion can be rapidly cooled by intensively increasing the injection amount of the cooling water at the beginning of the low speed section .

Therefore, when applied to the continuous casting process of a steel mill, it is possible to prevent the breakage of the cast tail portion during the continuous casting of the electric steel sheet material and the wide width material, which are susceptible to breakage of the cast tail portion, The injection amount of the cooling water injected to the cast steel frame at an early stage of the low speed section can be intensively increased while the casting speed and the holding time of the cast steel tail are appropriately determined and the cast tail portion is cooled sufficiently in the section before the # It is possible to prevent the molten steel from flowing out.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a facility to which a casting method according to an embodiment of the present invention is applied.
FIG. 2 is a graph and a graph for explaining changes in phase and nature of cast steel when a cast steel is cast according to an embodiment of the present invention. FIG.
FIG. 3 is a drawing and photographs illustrating a process and a result of the bursting of the cast tail portion when a cast steel is cast by a casting method according to a comparative example of the present invention.
FIG. 4 is a diagram showing an example of establishing a working pattern according to an embodiment of the present invention and constructing it in a control program.
FIG. 5 is a diagram illustrating results of establishing a control pattern according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating a method of determining the casting speed for each section at the end of the operation according to the embodiment of the present invention.

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 present invention relates to a casting method capable of preventing molten steel from leaking out of the cast iron part at the end of casting. Hereinafter, embodiments will be described with reference to a continuous casting process of an iron mill for casting an electric steel sheet material and a wide width material.

FIG. 1 is a view showing an apparatus to which a casting method according to an embodiment of the present invention is applied, and FIGS. 2 (a) to 2 (d) And Fig. 8 is a graph and a graph for explaining a change in the shape and nature of the casting.

FIGS. 3 (a) to 3 (d) are drawings and photographs illustrating a process in which bursting of the cast tail portion occurs when a cast steel is cast by a casting method according to a comparative example of the present invention, and the results thereof.

FIG. 4 is a diagram illustrating an example of establishing a control pattern according to an embodiment of the present invention. FIG. 5 is a flowchart illustrating a method of establishing a control pattern according to an embodiment of the present invention, Fig. FIG. 6 is a diagram illustrating a method of determining the casting speed per section at the end of the operation according to the embodiment of the present invention.

First, with reference to FIG. 1, a processing facility to which a casting method according to an embodiment of the present invention is applied will be described. The treatment facility may include a continuous casting facility. The processing facility includes a ladle 10, a tundish 20, an immersion nozzle 22, a mold 30, a bender 40 and a plurality of segments 50.

The ladle (10) is installed in a ladle turret, in which impurities are removed and the chemical composition is adjusted. The molten steel is poured into the tundish 20 through the shroud nozzle. Molten steel stored in the tundish 20 is injected into the mold 30 through the immersion nozzle 22. Molten steel is first solidified in the mold 30 and an initial solidification layer is formed and cast into the slab S. The cast steel S passes through the bender 40 provided on the lower side of the mold 30 and is drawn along the plurality of segments 50 in the casting direction. At this time, cooling water is injected into the casting by using the bender 40 and a plurality of nozzles provided for each segment. Thus, the cast steel S is secondarily cooled while being drawn in the casting direction, and the molding is completed.

The bender 40 may include a bender roll 41 and a nozzle 42 to guide the billet S using the bender roll 41 and to feed the billet 40 with cooling water . The segment closest to the vendor 40 among the plurality of segments 50 is referred to as a # 1 segment, the next segment is referred to as a # 2 segment, and the Nth nearest segment to the vendor 40 is referred to as a #N segment. Hereinafter, the # 1 segment is referred to as a one segment 50a. The work segment 50a may include a segment roll 51a and a nozzle 52a and draws the slab S using the segment roll 51a and uses the nozzle 52a to feed the slab S Cooling water can be sprayed. Other segments may also include segment rolls and nozzles. Each of the casting rolls is used to pull out the casting S and cool the casting S by using a nozzle.

The processing facility according to an embodiment of the present invention may further include a controller 60. [ The controller 60 can control the casting speed of the cast steel and the quantity of the cooling water sprayed on the cast steel depending on the progress of the operation by using each operation pattern established for each operation period. In particular, the casting speed and the ratio of the cooling water It is possible to effectively prevent the molten steel from leaking out of the cast steel frame part during operation. Here, the term " operation progress " means that the operation is performed as the time elapses. The operational pattern established for each operational period is, for example, a operational pattern established for each operational section. Also, the amount of rain may be, for example, the amount of injection.

Hereinafter, a casting method according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. FIG.

The casting method according to the embodiment of the present invention is a casting method according to the present invention in which molten steel is injected into a mold 30 to solidify the casting S into a casting S, a process in which the casting S is drawn out in a casting direction and cooled, And controlling the rate of casting of the cast steel S and the ratio of the amount of cooling water sprayed onto the steel strip S depending on the operation progress or the operation section using each of the established operation patterns.

Molten steel may include molten steel for casting a slab of an electric steel sheet material and molten steel for casting a slab of a wide width material. The molten steel for casting the slab of the electrical steel sheet material may have a silicon (Si) content of 3 wt% or more and a carbon (C) content of 0.08 wt% or less based on the total weight of molten steel. In this case, the higher the content of silicon, the more difficult it is to control the stress during solidification of the cast steel. The casting of the wide width material means a casting having a width of 1,500 mm or more in the long side direction. The molten steel has a grade operation code, and the operation pattern may be different for each operation code.

In the case of molten steel for casting a cast steel of an electric steel sheet material, when the cast steel is cast and cooled and the temperature is, for example, about 900 DEG C, the phase transformation from the body-centered cubic structure (BCC) to the face-centered cubic structure (FCC) occurs. As a result, the unit lattice volume filling ratio is changed from 68.02% to 74.05%, and the internal stress is generated according to the volume change. Fig. 2 (a) shows the solid phase of the body-centered cubic structure, and Fig. 2 (b) shows the solid phase of the face-centered cubic structure.

Also, in the case of molten steel for casting a cast steel of an electric steel sheet material, mechanical thermal expansion occurs at the interface between the molten steel in the cast steel and the solidification layer of the cast steel due to the composition of the material, and a tensile stress is generated. Changes in the mechanical properties of the cast steel depending on the composition of the steel are shown in (c) and (d) of FIG. 2, respectively.

FIG. 3 is a diagram illustrating a process and a result of a bursting of a cast tail portion when a cast steel is cast according to a casting method according to a comparative example of the present invention. The casting method according to the comparative example of the present invention is a casting method for performing the terminal operation without using the terminal operation pattern according to the embodiment of the present invention, for example, corresponds to a conventional continuous casting operation.

In the case of molten steel for casting a steel strip, the cooling water is injected into the nozzle (N) at the end of the operation, and during the drawing of the steel strip (S '), As shown in FIG. 3A, when the pressure is concentrated on the capped portion of the cast steel bare portion S 'due to the difference between the tensile stresses due to solidification, the cast steel bare portion S' The liquid molten steel may leak out due to time lapse at the # 5 to # 6 segment points.

That is, due to the internal stress due to the phase change and the mechanical tensile stress due to the cooling water injection in the high-coexistence region, the stress is concentrated on the fragile portion of the cast tail portion and the molten steel flows out. Thereafter, when the cast tail portion is drawn along the casting direction and tilted at a predetermined position at a predetermined angle, the non-solidified molten steel in the cast steel flows out. 3 (b) to 3 (d) show a state in which the segment roll is now fused.

As described above, in the comparative example, the molten steel flows out during operation and the segment rolls are burned, resulting in facility troubles. Therefore, there is a problem that the segments must be exchanged, and when such measures are delayed or insufficient, a crack occurs on the side of the long side of the main shaft and the quality is deteriorated.

Therefore, in the embodiment of the present invention, during the end of the operation, an end-of-operation pattern for controlling the casting speed of the cast steel and the quantity of the cooling water sprayed on the cast steel is established, and during the casting of the steel sheet material and the wide- At the end of the casting, the casting tail part can form a sufficient solidification layer in the mold by adjusting the stress change and the cooling rate according to the casting speed at the end of the casting, and then pass the bender and work segment at optimum speed, So that it can be cooled to an optimum state without shrinkage of the resin. That is, in the embodiment of the present invention, the optimum casting speed and cooling water amount can be obtained at the end of the operation by utilizing the terminal casting pattern.

Hereinafter, a casting method according to an embodiment of the present invention will be described.

First, each operation pattern is established according to the progress of the operation. Specifically, an initial operation pattern, a medium-term operation pattern, and an end-of-operation operation pattern are established in accordance with a time-series operation progress. Each operation pattern can include information on the casting speed, casting acceleration, holding time, and cooling water amount per position in each time series detail section.

The casting speed means the speed at which the casting is drawn in the casting direction in each section. The casting acceleration refers to the amount of change in the speed at which the cast steel is pulled out in the casting direction in a connection section between one section and another section when the casting speed is different between one section and another section that are close in time. The casting speed and casting acceleration may be constant values within each section.

The retention time means an elapsed time from the beginning of a section to the end of a section, for example, and can be obtained from a time difference between a start point and an end point of each section. That is, the holding time is the time at which the operation is performed for each section. The amount of cooling water amount per position means the amount of cooling water (also referred to as the amount of injection) that is injected into the casting for each position in the casting direction when the operation is performed in each section.

For example, when the non-water quantity values of the cooling water injected into the slab from the nozzles provided in each segment are all the same in one segment, one segment has one value as the cooling water non-quantity information at the entire segment position.

Also, if the non-quantity value of the cooling water injected from the nozzle provided in each segment in the segment is different for each segment, one segment has the value of the cooling water non-quantity information for each corresponding segment position.

In the embodiment of the present invention, the initial operation pattern and the medium-term operation pattern are not particularly limited. For example, the initial operation pattern includes a casting of an electric steel sheet material and a predetermined operation pattern used at the beginning of a continuous casting operation for casting a wide cast slab. The middle operation pattern may be a predetermined operation pattern used in the middle of the continuous casting operation for casting the slab of the electric steel sheet material and the wide-width cast slab.

The end working pattern according to the embodiment of the present invention is applied to the end of the continuous casting operation for casting the cast steel of the electric steel sheet and the wide cast steel, so as to prevent the molten steel from leaking out of the cast steel frame T during the operation .

For example, when performing the continuous casting operation for casting a steel strip material and a wide-width material, it is necessary to use an electric steel sheet material and a wide-width steel material for minimizing the damage of the cast tail portion due to the theoretical solidification of molten steel and mechanical thermal deformation at the end of the operation Establish end-of-work patterns. Specifically, the casting tail portion is subjected to low-speed casting for about 2 minutes (min) to 3 minutes at a casting speed of 0.8 m / min or more before reaching the final casting speed of 1.7 m / min, It is possible to increase the holding time by increasing the holding time so as to sufficiently establish the terminal working pattern so as to sufficiently cool the cast steel frame portion T at the positions of the vendor and the # 1 to # 2 segments.

In addition, by increasing the quantity of the cooling water injected from the bender and the # 1 segment, for example, the one segment 50a, it is possible to increase the quantity of the cooling water injected from the # 1 segment, for example, Can be established. Therefore, it is possible to sufficiently secure the cooling time of the cast steel frame part T, for example, at a position of the # 5 to # 6 segment where the cast steel frame part T is inclined at a predetermined angle, Can be prevented.

The end-of-operation pattern may include information on the casting speed, casting acceleration, and holding time of each section according to the time elapsed at the end of the operation, and may include information on the amount of the cooling water for each position of the cast steel frame T. The casting speed, the casting acceleration, the holding time, and the cooling water amount information described above can be determined according to the operation code of the steel. In the embodiment of the present invention, the cast steel of the electric steel sheet and the wide- It depends.

A detailed description of the terminal operation pattern will be described below together with explaining the process of controlling the casting speed of the casting machine and the amount of the cooling water sprayed on the casting machine according to the progress of the operation using each operation pattern.

After each operation pattern is established according to the progress of the operation, each operation pattern is constructed as a series of logic according to time lapse, for example, as shown in Fig. 4, and is provided on the process control program. This is illustrated in FIG.

5, for example, Steel Grade is a grade operation code, Vt is a casting speed of a slave section described later in the terminal operation, and V5 is a casting speed of a low speed section which will be described later in the last section. V6 is the casting speed of the constant velocity section which will be described later in the terminal operation, Gamma1 to Gamma3 are the casting acceleration of each acceleration section described later in the terminal operation, and Tm3 and Tm4 are the holding time of the low speed section and the constant speed section, respectively. That is, FIG. 4 shows the operational patterns of the different types of steel, and the terminal operational patterns in detail on one screen.

3 and 4 are intended to illustrate a process of constructing and using each operation pattern on a process control program, and the items described in the respective drawings are used to limit the embodiments of the present invention It is not.

Thereafter, molten steel is injected into the mold 30 to solidify the molten steel into the cast steel S, and the molten steel is drawn in the casting direction and cooled. For example, the molten steel contained in the ladle 10 is injected into the tundish 20, temporarily stored and prepared, and the molten steel stored in the tundish 20 is injected into the mold 30.

The molten steel is first solidified in the mold 30 and cast into the cast (S). The cast steel S passes through the bender 40 provided on the lower side of the mold 30 and is drawn along the plurality of segments 50 in the casting direction. At this time, cooling water is injected into the casting by using a plurality of nozzles provided in each of the bender 40 and each of the segments 50. Thus, the cast steel S is secondarily cooled while being drawn in the casting direction.

In the process of drawing the slab S, the casting speed of the slab and the amount of the cooling water sprayed on the slab are controlled according to the progress of the operation, using each operation pattern established for each operation period. At the beginning of operation, the casting speed of the casting and the amount of the cooling water sprayed on the casting are controlled and the casting is pulled out. Then, the casting speed of the casting and the amount of the cooling water sprayed on the casting are controlled during the middle of the operation, and the normal casting is pulled out. At this time, the mid-process casting speed may be, for example, 1.3 to 1.5 m / min. Also, the casting speed may be decreased stepwise from a predetermined time before the middle of the operation to the end of the middle of the operation, wherein the casting speed may be in the range of 1.0 to 0.8 m / min.

Thereafter, at the end of the operation, the casting speed of the casting and the amount of the cooling water sprayed on the casting are controlled by utilizing the terminal operation pattern and the casting S is pulled out. At this time, the end of the operation may be the time when the amount of the molten steel remaining in the tundish 20 is 30 ton or less, or the molten steel in the turn-dish 20 is completely exhausted, It may be the point in time at which it was injected. On the other hand, a capping operation can be performed using a predetermined jig at the end of the operation.

In the embodiment of the present invention, when the casting speed of the spindle frame T is controlled at the end of the operation, it is possible to relatively increase the holding time of the low-speed section among the entire sections of the end of the operation by utilizing the terminal operation pattern.

Also, when controlling the amount of cooling water sprayed to the cast steel frame at the end of the operation, it is possible to control the amount of cooling water sprayed on the cast steel frame part differently depending on the position of the cast steel tail part by utilizing the last operation pattern.

Accordingly, the unstacked portion of the cast steel frame part (T) and the molten steel outflow due to the change in internal stress can be prevented.

First, the process of controlling the casting speed of the cast steel frame (T) is explained by utilizing the terminal operation pattern at the end of the operation. Thereafter, the amount of the cooling water sprayed on the cast steel frame is utilized The control process will be described.

Referring to FIG. 6, the entire section of the end of the operation includes the low speed section C1, the speed change section and the dependent section C3 in the order of time lapse. At this time, the speed change section may include a plurality of acceleration sections C 'and at least one constant speed section connecting between the acceleration sections. For example, the speed change section may include a first acceleration section, a constant speed section (C2), and a second acceleration section in the order of time lapse. V1 is the casting speed of the low speed section, V2 is the casting speed of the constant speed section, and Vt is the casting speed of the slave section. On the other hand, the casting acceleration of each acceleration section may be a constant value and may be equal to each other. For example, the casting acceleration may be 1.0 m / min ² .

In the embodiment of the present invention, when controlling the casting speed of the cast tail portion at the end of the operation, the holding time of the low speed section is increased and the holding time of the speed changing section is reduced. That is, the maintenance time of the low-speed section having the smallest casting speed among the sections of the end of the operation can be selected and relatively long.

In this case, the maintenance time of the low-speed section from the start point of the end of the operation to the end of the low-speed section can be increased while maintaining the total time obtained by adding the maintenance time of each section of the operation end, It is possible to smoothly cool the cast tail portion, thereby preventing the cast tail portion.

In the embodiment of the present invention, when controlling the casting speed of the cast tail portion at the end of the operation, the holding time of the low speed section is increased from 2 min to 3 min. More specifically, the casting speed of the low-speed section is set to 0.8 m / min, and the holding time of the low-speed section is set to 2 min 30 sec. It was confirmed that the cast tail portion can be cooled smoothly at the end of the casting of the electric steel sheet and the wide width material by performing the operation with the casting speed and the holding time described above.

On the other hand, when controlling the casting speed of the cast tail part at the end of the operation, the casting speed of the subordinate section in the final section of the tail end can be set to 1.7 m / min or 1.7 m / min. This speed is the final target speed at the end of the casting when casting the steel of the molten steel to which the embodiment of the present invention is applied, resulting in an optimal casting speed while repeatedly performing the operation.

On the other hand, the starting point of the slave section can be determined to have a predetermined time interval from a predetermined time point at which the end of the operation is started, and the casting acceleration for reducing the load of the casting during the casting operation is 1.0 m / min The holding time of the speed change section can be obtained on the basis of this, and the casting speed and the holding time of the constant speed section in the speed change section can be obtained.

As described above, in the embodiment of the present invention, the casting speed from the start of the end of the operation to the end of the low-speed section is set at 0.8 m / min and the holding time is set at 3 minutes and 30 seconds. So that it can be sufficiently cooled while staying in the work segment for an appropriate period of time.

Hereinafter, a process of controlling the amount of cooling water sprayed to the cast steel frame by utilizing the terminal operation pattern at the end of the operation will be described.

In the embodiment of the present invention, it is possible to control the amount of the cooling water sprayed to the spindle tail part differently according to the position of the spout tail part by utilizing the terminal operation pattern when controlling the flow rate of the cooling water sprayed to the spout part at the end of the operation have.

As described above, the bender 40 and the plurality of segments 50 are disposed on the lower side of the mold 30 along the casting direction to perform the drawing and cooling of the slab S, The amount of the cooling water injected to the spindle frame portion T at the positions of the bender 40 and the one segment 50a is different from that of the cooling water injected to the cast steel frame portion at different positions Can be controlled to be larger than the rain quantity. That is, cooling water may be further added to the casting tile portion when the casting tail portion passes through the bender and the work segment to perform cooling of the casting.

At this time, when the billet is a rectangular cast steel, the quantity of the cooling water jetted to the side of the long side of the cast tail portion in the bender and the segment is made different and the quantity of the cooling water jetted to the short side is made different, .

In the embodiment of the present invention, when controlling the amount of cooling water to be sprayed to the spigot tail (T) at the end of the operation, the amount of cooling water in the bender and one segment is set to 50 to 300 L / Was set to 2 min 30 sec to 4 min. More specifically, the ratio of the amount of the cooling water jetted to the side of the long side of the spigot tail portion T in the bender 40 and the one segment 50a is set to 100 to 300 L / min, Was set at 50 to 150 L / min. More preferably, the spraying time of the cooling water injected to the long side of the spigot tail portion T in the bender 40 and one segment 50a is 200 l / min while the injection time thereof is 3 min 30 sec. And the spraying time of the cooling water was set to 3 min. 30 sec. Accordingly, the cast tail portion can be smoothly solidified by spraying the optimum cooling water to the cast steel while the cast tail portion passes the bender portion and the one segment from the start of the end of the operation. Thereafter, the cast tail portion passes through the remaining segments, Through the banding section, even if the posture changed gradually from the vertical to the horizontal, the casting was performed well without leakage of molten steel. Thereafter, casting is terminated when the cast tail section completely passes through the slave section.

As described above, in the embodiment of the present invention, the time of the low-speed section is extended to 3 minutes and 30 seconds in the plurality of sections of the end of the operation, and at the beginning of the low-speed section, It is possible to smooth the solidification of the cast tail portion by spraying the cooling water. Particularly, in the case of casting a slab of an electric steel plate material and a wide width material, conventionally, there has been a problem that the cast tail portion is undercooled or the development of the coagulation angle is slowed down. As a result of performing the operation under the above- Can be stably performed.

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. In addition, it should be noted that the configurations and the methods disclosed in the above embodiments of the present invention may be combined or crossed with each other and modified into various forms, and these modifications may be considered as the scope of the present invention. That is, the present invention may be embodied in various forms without departing from the scope of the appended claims and equivalents thereto, and it is to be understood and appreciated by those skilled in the art that various changes in form and details may be made therein without departing from the spirit of the invention You will understand.

30: Mold 40: Bender
50: Segment T: Cast steel Tee part

Claims (14)

A process of injecting molten steel into a mold and solidifying the molten steel into a cast steel;
Drawing the cast steel in a casting direction and cooling it; And
And controlling the casting speed of the casting die and the injection quantity of the cooling water injected into the casting machine in accordance with each operation pattern established for each of the operation sections of the initial, middle, and end sections of the operation,
When the casting speed of the cast tail portion is controlled by utilizing the last operation pattern at the end of the operation in the above operation section,
Wherein the control unit relatively increases the holding time of the low speed section, which is the section with the lowest casting speed, among the entire sections of the end of the working period including the low speed section, the speed changing section and the dependent section in the order of time, Casting method to reduce time. delete The method according to claim 1,
The speed change section
At least one constant velocity section connecting a plurality of acceleration sections and respective acceleration sections, or includes at least one of a first acceleration section, a constant velocity section and a second acceleration section according to the progress of the operation, and the casting acceleration of each acceleration section is the same ,
When the casting speed of the cast tail portion is controlled at the end of the operation,
Wherein the holding time of the constant velocity section is decreased after increasing the holding time of the low speed section. The method according to claim 1,
When the casting speed of the cast tail portion is controlled at the end of the operation,
Wherein the holding time of the low speed section is increased from 2 min to 3 min, and the holding time of the other section is decreased. The method of claim 4,
When the casting speed of the cast tail portion is controlled at the end of the operation,
Wherein the casting speed of the low-speed section is controlled at 0.8 m / min or more. The method according to claim 4 or 5,
When the casting speed of the cast tail portion is controlled at the end of the operation,
Wherein the casting speed of the slave section is controlled to 1.7 m / min among the entire section of the end of the operation. The method according to claim 1,
Wherein the terminal operation pattern includes information on a casting speed, a casting acceleration, and a holding time of each section of the end of the operation, the molten steel has a strong operation code,
Wherein the casting speed, the casting acceleration and the holding time information for each of the sections of the end of the operation are determined according to the grade operation code. The method according to claim 1,
When the injection amount of the cooling water injected into the cast steel frame at the end of the operation is controlled,
A casting method for making a spray amount of cooling water sprayed on a cast steel frame part by position of a cast tail part by using a terminal operation pattern. The method of claim 8,
A bender and a plurality of segments are disposed on the lower side of the mold along the casting direction to perform drawing and cooling of the cast steel,
When the injection amount of the cooling water injected into the cast steel frame at the end of the operation is controlled,
Wherein the injection amount of the cooling water injected into the cast strip part at the position of the one segment closest to the bender and the bender is controlled to be larger than the injection amount of the cooling water injected to the cast strip part at another position. The method of claim 9,
When the injection amount of the cooling water injected into the cast steel frame at the end of the operation is controlled,
The injection quantity of the cooling water injected to the long side of the cast tail part in the bender and the one segment and the injection quantity of the cooling water injected to the short side of the cast tail part are controlled differently. The method of claim 9,
When the injection amount of the cooling water injected into the cast steel frame at the end of the operation is controlled,
The injection amount of the cooling water is controlled to be 50 to 300 L / min in the bender and the one segment, and the injection time of the cooling water is controlled to be 2 to 30 sec to 4 min. The method of claim 11,
Wherein the spray amount of the cooling water sprayed to the long side of the spout tail portion in the bender and the one segment is set to 100 to 300 L / min and the spray amount of the cooling water sprayed to the short side is set to 50 to 150 L / min. The method of claim 8,
Wherein the last working pattern further includes information on the injection amount of cooling water for each position of the cast tail part,
Wherein the injection amount information of the cooling water by the position of the tail portion of the tail end of the end of the operation is determined according to the proficiency operation code. The method of claim 7 or claim 13,
Wherein said molten steel comprises molten steel for casting a slab of an electric steel sheet material or a wide width material having a width of at least 1500 mm in the long side direction.

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