JPH10225765A - How to reuse tundish for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently operate a tundish by removing residual steel slag in a tundish after continuous casting, suppressing damage to a nozzle refractory and a refractory therearound. To provide a method for reusing a tundish for continuous casting that can be used. A tundish (14) for holding molten steel (11).
Through a nozzle refractory 15 provided at the bottom of the mold 16
After the first continuous casting in which molten steel 11 is poured into the inside to produce a cast slab, the remaining steel slag 28 such as molten steel 11, ingot, slag and the like in the tundish 14 is removed, and second continuous casting is performed. In the method of reusing the tundish for continuous casting, after the first continuous casting is completed, the remaining steel slag 28 in the tundish 14 is discharged using the remaining steel slag discharging means.
After removing the remaining steel slag and repairing the tundish at the time of discharging the remaining steel slag of No. 4, the second continuous casting is performed after preheating the tundish 14 by reusing at least a part of the nozzle refractory 15. Do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting tank capable of performing highly productive operation while minimizing refractory damage to the tundish when the tundish is maintained and reused. Regarding how to reuse dishes.

[0002]

2. Description of the Related Art In a continuous casting method, when a molten steel is poured into a continuous casting mold, a tundish for adjusting the injection speed and the like is indispensable while making the components and temperature of the molten steel uniform. At the end of continuous casting of such a tundish, a large amount of residual steel slag such as solidified metal or slag of molten steel adheres to the tundish, and the lining of the coating is damaged. Often not. For this reason,
To improve the productivity of continuous casting while replacing multiple tundishes or repairing the same tundish, improve the efficiency of tundish maintenance work in order to suppress the increase in refractory intensity. is required. For example, the following techniques are known as methods related to a maintenance method for smoothly performing an operation cycle of continuous casting to maintenance to continuous casting in such a tundish.

Japanese Patent Application Laid-Open No. 7-284891 discloses a continuous casting tundish in which a discharge port for discharging residual molten steel and residual steel slag (residue) is provided at an upper end edge of the tundish. It is provided on the upper edge of the tundish wall in a plane parallel to the axis of rotation, and the outlet is provided with a closing lid. A tundish is described in which a discharge opening is closed with a closing lid after an object is discharged from the discharge opening to prevent heat dissipation. Japanese Patent Application Laid-Open No. 4-351251 discloses that a recess is formed in a molten steel injection flow falling area (stirring area) injected from a ladle via a long nozzle, and an immersion nozzle (immersion nozzle) is provided downstream of the molten steel injection flow falling area. In a continuous casting tundish provided with a slag / non-metallic inclusions floating area, the recess is enlarged to the floating area, and a slag cut weir to prevent slag from flowing out from the stirring area to the floating area is provided in the floating area. The tundish is installed so as to separate the slag from molten steel by improving the yield at the end of casting by installing the stirring area and the floating area to a position lower than the bottom but higher than the bottom of the stirring area. Have been described. Japanese Patent Application Laid-Open No. 53-32830 discloses that a tundish in a state where some residual hot water remains after casting is placed on a tundish mounting table located at a predetermined distance from a swing tower by a crane. , Remove the tundish top lid, reverse rotation of the tundish, return the remnants in the tundish to the pot carriage that traverses the lower part of the tundish mounting table, and then rotate the tundish again to turn the opening sideways. There is described a method for repairing and repairing a tundish in which a residue stuck to the inner peripheral wall of the tundish is completely scraped out and removed by a scraper located on the side of the tundish mounting table.

[0004]

However, the above-mentioned methods have the following problems. In a tundish disclosed in JP-A-7-284891, in which the residue is discharged from the discharge port and the discharge port is closed with a closing lid to prevent heat dissipation, the remaining molten steel or metal is oxidized during standby, Such oxides contaminate the molten steel to be processed at the time of the next continuous casting, and cause factors such as nonmetallic inclusions. In the method disclosed in Japanese Patent Application Laid-Open No. 4-351251, in which the slag and the molten steel are separated by a noro-cutting weir and the tundish is hot-maintained, metal is left in the nozzle refractory part at the end of casting, so that the metal is significantly reduced. Workability is reduced,
Further, the above-mentioned problem caused by the oxidation of the metal is not completely solved. In the repair / maintenance method disclosed in Japanese Patent Application Laid-Open No. 53-32830 for scraping off and removing the residue adhered to the inner peripheral wall of the tundish in a rollover state of the tundish, since the entire tundish is cooled, a nozzle refractory or a coating layer is formed. However, there is a disadvantage that the damage of the refractory increases and the basic unit of the refractory increases.

[0005] The present invention has been made in view of such circumstances, and while efficiently removing the residual steel slag in the tundish after continuous casting, the nozzle refractory and damage to the refractory around the nozzle refractory. An object of the present invention is to provide a method of reusing a tundish for continuous casting, which can suppress the operation and efficiently operate the tundish.

[0006]

According to the present invention, there is provided a semiconductor device comprising:
The method for reusing a tundish for continuous casting according to the first aspect is a first continuous casting method in which the molten steel is poured into a mold through a nozzle refractory provided at the bottom of the tundish holding the molten steel to produce a slab. After performing the above, in the reuse method of the continuous casting tundish for performing the second continuous casting by removing residual steel slag such as molten steel, ingot, slag, etc. in the tundish, After the end, the residual steel slag in the tundish is discharged using residual steel slag discharging means, and then the residual steel slag remaining when the residual steel slag of the tundish is discharged and the tundish are repaired, A second continuous casting is performed after reheating at least a portion of the nozzle refractory and preheating the tundish. The residual steel slag in the tundish is steel remaining in a molten state, ingots and slag adhered in a solidified state, and the like. By using the residual steel slag discharging means, most of the residual steel slag can be discharged, but since a part of the adhered metal and slag remains, the residual steel slag is removed by removing the residual steel slag. Prevents contamination of molten steel in the second continuous casting. In addition, refractories of tundish are coated on the steel shell that forms the furnace shell, and the refractories used for the lining are generally alumina-based, wax-based, chamotte-based, etc. Brick (regular refractory) or irregular refractory is used. A coating layer made of magnesia or the like is sprayed or applied to the contact surface with the molten steel in the tundish, which is the surface of this refractory lining, and is used due to melting of the refractory constituting the tundish Generation of nonmetallic inclusions is suppressed. The nozzle refractory is a refractory that forms a molten steel flow path from the bottom of the tundish such as an upper nozzle, a sliding nozzle, a lower nozzle, and an immersion nozzle to a mold. Such a nozzle refractory is the most expensive refractory among the refractories constituting the tundish,
By reusing the nozzle refractory, it is possible to effectively suppress an increase in the refractory basic unit. Tundish repair refers to repair of the coating layer of the tundish or partial repair of the refractory lining.

[0007] The method for reusing a tundish for continuous casting according to a second aspect of the present invention is the method for reusing a tundish for continuous casting according to the first aspect, wherein the refractory material of the nozzle comprises a remnant of steel residue in the tundish. Heat is retained in at least some of the steps of discharging, removing residual steel slag, and repairing the tundish. Heat retention refers to an operation of suppressing the dissipated heat by covering the nozzle refractory with a heat insulating cover or the like, or an operation of heating the lower part of the nozzle refractory with a gas burner, and combining any of these operations. Is also possible.
Such an operation is performed for the purpose of preventing abrasion of the nozzle refractory due to cracks or the like due to a temperature drop.

[0008] The method for reusing a tundish for continuous casting according to the third aspect is the method for reusing a tundish for continuous casting according to the first or second aspect, wherein the residue remaining when the steel residue of the tundish is discharged is removed. In removing the steel slag, a part of the inside of the tundish is forcibly cooled to remove the remaining steel slag. With the forced cooling of a part of the tundish, after the residual steel slag is discharged, the remaining steel slag is forcibly removed by air blowing, steam blowing, water spraying, etc. Cooling. Thereby, the residual steel slag can be efficiently removed without cooling the entire tundish.

A method for reusing a tundish for continuous casting according to a fourth aspect of the present invention is the method for reusing a tundish for continuous casting according to any one of the first to third aspects, wherein the residual steel residue of the tundish is provided. Is removed by using a pick to remove the residual steel residue remaining at the time of discharging, or the metal fitting is welded to the residual steel residue and then the metal fitting is pulled to remove the residual steel residue. The pick for removing the remaining steel residue is a bar having a sharp tip, and is a rod-like body from which the metal residue, in particular, the metal part can be peeled off. By providing a hook at the tip of such a pick, the metal can be easily removed. Welding refers to welding a stud, which is a metal fitting, directly to the remaining steel slag by means such as electric welding or gas welding.

A method for reusing a tundish for continuous casting according to a fifth aspect of the present invention is the method for reusing a tundish for continuous casting according to any one of the first to fourth aspects, wherein the tundish is repaired when the tundish is repaired. The coating surface temperature of the coating layer to be applied is 200 to 900 ° C. Construction surface temperature is 2
If the temperature is lower than 00 ° C., the thermal stress applied to the lining refractory and the nozzle refractory increases, causing spalling (cracking), which is a factor of shortening the life of the refractory. On the other hand, if the working surface temperature is higher than 900 ° C., the remaining steel slag such as ingots is oxidized, and the concentration of nonmetallic inclusions in the molten steel increases during the next continuous casting, which is not preferable. In addition, it is necessary to complete heat-resistant auxiliary equipment in a tundish maintenance site and the like, and problems such as deterioration of the working environment arise.

The method for reusing a tundish for continuous casting according to a sixth aspect of the present invention is the method for reusing a tundish for continuous casting according to any one of the first to fifth aspects, wherein the residual steel slag discharging means is provided. And a residual steel slag discharge hole provided in the tundish tilting device or the bottom of the tundish. By using the tilting device or the residual steel slag discharge hole, the residual steel slag can be discharged so that the residual steel slag does not adhere to the nozzle refractory or in the vicinity of the nozzle refractory. Damage to the nozzle refractory due to metal removal can be prevented.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIGS. 1 (a), (b), (c)
Is a method for reusing a tundish for continuous casting according to an embodiment of the present invention, Comparative Example 1 performing cold repair,
And FIG. 2 is a side sectional view of a continuous casting facility to which the method for reusing the tundish for continuous casting is applied, and FIG. 3 is an illustration of the tundish after the residual steel slag is discharged. Fig. 4 is an explanatory view of a tundish in a bullion removing operation, Fig. 5 is an explanatory view of a tundish in a repair operation, and Fig. 6 is an explanatory view of a tundish in a preheating operation.

First, a continuous casting facility 10 to which a method for reusing a tundish for continuous casting according to an embodiment of the present invention will be described. As shown in FIG. 2, the continuous casting equipment 10 includes a ladle 12 for holding molten steel 11 and a ladle 12.
A long nozzle 13 provided at the bottom of the steel, and the molten steel 11 supplied through the long nozzle 13 to receive a molten steel component,
Tundish 14 for equalizing molten steel temperature etc.
And a nozzle refractory 15 provided at the bottom of the tundish 14, and a mold 16 into which the molten steel 11 is injected via the nozzle refractory 15.

The ladle 12 is a substantially cylindrical molten steel container having a capacity of about 300 tons lined with a refractory such as alumina or silica, and a long nozzle 13 made of alumina carbon is used by using a molten steel flow control device (not shown). The flow rate of the molten steel 11 supplied to the tundish 14 can be controlled. When the molten steel 11 in the ladle 12 runs out, the ladle 12 is replaced with the next ladle 12 as necessary, and the casting is continuously performed.

The tundish 14 is a holding vessel having a capacity of about 25 tons of molten steel having a substantially boat-like shape, and its refractory lining 17 is generally made of a brazeite, chamotte, alumina-based brick or the like with little metal. Alternatively, an amorphous refractory is used. Then, a coating layer 18 of a predetermined thickness made of magnesia or the like is applied to the contact surface with the molten steel 11 by spraying or coating. For this reason, the generation of nonmetallic inclusions due to the erosion of the refractory is suppressed.

The nozzle refractory 15, as shown in FIG. 2, comprises an upper nozzle 19 for introducing the molten steel 11 in the tundish 14 to the mold 16, and three plate bricks, and the molten steel passage holes of the plate brick. And a immersion nozzle 22 for supplying the molten steel 11 into the mold 16 through a lower discharge hole 21 by controlling the flow rate of the molten steel 11 by moving the positions of the molten steel 11 to each other. . The configuration of the nozzle refractory 15 is an example. For example, a nozzle receiver (not shown), a lower nozzle, or the like may be added to this configuration as necessary, and a two-plate sliding nozzle may be used instead of the three-plate sliding nozzle 20. The immersion nozzle 22 has a total length of about 700 to 80.
0mm, outer diameter about 100-150mm, inner diameter about 50-70
It is a generally tubular refractory mainly composed of a substantially cylindrical alumina carbon material of mm. About 60 × 40m on the bottom side
An ejection hole 21 having a substantially elliptical shape of m or a substantially rectangular shape of about 60 × 60 mm is provided so as to oppose two places. Also,
The continuous casting equipment 10 is provided with a transfer device (not shown) for the tundish 14, and after the end of the continuous casting,
The tundish 14 can be transferred from a continuous casting position on the casting bed to a tundish tilting table, a tundish repair station, or the like.

Next, a method for reusing a tundish for continuous casting according to an embodiment of the present invention applied to the tundish 14 in the continuous casting facility 10 is shown in FIG.
This will be described with reference to FIG. In step S-1 shown in FIG. 1A, after continuous casting (first continuous casting) is completed, the immersion nozzle 22 is removed from the tundish 14 as necessary, and the tundish 14 is moved from the casting position to the tundish. The remaining steel slag 28 in the tundish 14 is discharged by tilting the tilting table by the tilting device of the tundish 14, which is an example of the remaining steel slag discharging means, after being transferred onto the tilting table. At this time, the temperature in the tundish 14 is approximately 800 to 1000 ° C. In addition, residual steel slag
As another method for discharging the residual steel 8, it is also possible to provide a residual steel slag discharge hole which is an example of a residual steel slag discharge means (not shown) at the bottom of the tundish 14 and discharge the residual steel slag from the residual steel slag discharge hole. .

Tundish (TD) in step S-2
In cooling, as shown in FIG. 3, a stud 23 which is an example of a metal fitting is bonded (welded) to the molten steel 11 remaining in the tundish 14 or the residual slag 28 made of slag by a general means such as electric welding. And fix it. During this time, forced cooling is performed. However, in order to prevent cooling of the nozzle refractory 15 and its surroundings, the nozzle refractory 15 excluding the immersion nozzle 22 and its surroundings are burned using a burner 24 (see FIGS. 5 and 6) or the like. Heat it. Thereby, the thermal shock generated when the nozzle refractory 15 is rapidly cooled can be reduced, and the nozzle refractory 15 can be prevented from being damaged.

In the next step S-3, a wire 25 is attached to the stud 23 as shown in FIG. 4 and a metal part is mechanically removed from the tundish 14 by a winding device (not shown) which is an example of the metal removing means. To separate. At the time of this metal removal, the metal can be peeled off with a pick or a bar, etc., or a metal removal device or human power that directly holds and scrapes the metal can be used in combination, making it efficient even at high temperatures. Ingot removal becomes possible.

Tundish (TD) in step S-4
In the breaking operation, as shown in FIG. 5, the nozzle hole portion of the nozzle refractory 15 is heated mainly from the inside or outside of the tundish 14 by using the burner 24 and the simple burner 26, and At the time of the removing operation or the continuous casting, an operation of removing the portion of the coating layer 18 and the lining refractory 17 which have been deteriorated by using a pick or the like is performed. The temperature in the tundish 14 in step S-4 is 300 to 500 ° C., and the temperature of the nozzle refractory 15 excluding the immersion nozzle 22 in the heated state is 500 to 1000 ° C.

At the time of the TD repair work in step S-5, the heating of the nozzle refractory 15 is continued as shown in FIG. 5, and the damaged portion such as the coating layer 18 or weir removed in step S-4 is removed. The magnesia coating material is sprayed using the spray nozzle 27 to repair the tundish 14. In addition, the construction surface temperature of the coating layer is maintained at 200 to 900 ° C, and the average temperature in the tundish 14 during this time is in the range of 300 to 500 ° C.

Subsequently, the tundish 14 is moved to a casting position as necessary by using a transfer device for the tundish 14, and as shown in FIG. Burner 24
Then, the inside of the tundish 14 is preheated (preheated) to a predetermined temperature, for example, 900 to 1200 ° C. by using the simple burner 26 (step S-6). After doing so, the next continuous casting (second continuous casting) can be started.
In steps S-2 to S-6, since the heat retention of the nozzle refractory 15 is performed, the thermal shock applied to the nozzle refractory 15 is reduced, and the damage can be prevented. And
The tundish rotation time required from the end of the continuous casting to the start of the next continuous casting is 5 to 7 hours, and the refractory cost required for the tundish repair is shown in Comparative Example 1 described later.
And the quality such as the concentration of inclusions in the slab was better than that of Comparative Example 2 described later.

Here, comparative examples 1 and 2 will be described in order to clarify the effect of the method for reusing a tundish for continuous casting according to one embodiment of the present invention. In Comparative Example 1, as shown in FIG. 1B, the tundish (TD) transfer in the tundish maintenance work (step S-
11) From tundish (TD) repair (step S-
This is an example in which the nozzle refractory 15 is not actively heated over the period up to 15), and the tundish (TD) repair (step S-15) is performed at a temperature of 30 to 80 ° C. Hereinafter, Comparative Example 1 will be described in detail. FIG.
In step S-11 shown in (b), after continuous casting, the immersion nozzle 22 is removed from the tundish 14 as necessary, and the tundish 14 is transferred from the casting position to the maintenance place by a crane or the like. Then, the stud 23 is previously inserted into the remaining steel slag 28 in the tundish 14 to solidify the remaining steel slag 28. At this time, the temperature in the tundish 14 is 800 to
1000 ° C.

The tundish (T) of step S-12
D) In cooling, cool air is supplied into the tundish 14 to cool the tundish 14 to a predetermined temperature of 30 to 80 ° C. In step S-13, the bullion is separated from the tundish 14 by lifting the stud 23 or other mechanical means. In the tundish (TD) breaking operation in step S-14, the portions of the coating layer 18 and the lining refractory 17 that have been worn and deteriorated are removed.
In addition, the temperature in the tundish 14 in step S-14 is 30 to 80C, and the temperature of the nozzle refractory 15 is 30 to 80C. In the repair of the tundish (TD) in step S-15, repair of a damaged portion such as the coating layer 18 or a weir is performed. During this time, the average temperature in the tundish 14 is in the range of 30 to 80C. Subsequently, the tundish 14 is moved to the casting standby position, and after setting the immersion nozzle 22 and the like, the inside of the tundish 14 is heated to a predetermined temperature of 1000 to 1200 ° C. using a burner.
(Step S-16) to start the next continuous casting.

In the comparative example 2 shown in FIG. 1 (c), the residual steel slag 28 of the tundish 14 is discharged after the end of the continuous casting (step S-21).
An example in which nozzle maintenance (step S-22) such as replacement of the immersion nozzle 22 is performed in a high temperature state of 00 to 1300 ° C is shown.

Table 1 shows the results of continuous casting in the above-described embodiment, Comparative Examples 1 and 2, respectively. In addition, refractory cost, tundish (T
D) The maintenance load and the quality of the cast slab are both indexed so as to be the reference 1 in Comparative Example 1, and the higher the indexed numerical value, the better the result. For example, in the case of the refractory cost, each reciprocal is calculated for the cost value, and other cases are indexed using the value of Comparative Example 1 as a reference value. Further, in the case of Comparative Example 2, there is a steel type restriction for a steel type having a narrow specification range, but there is no such steel type restriction for the present embodiment and Comparative Example 1. As shown in the table, in the present embodiment, the tundish (TD) rotation time is 5 to 7 hours, which is significantly larger than the 18 to 20 hours in Comparative Example 1 in which the tundish 14 is repaired and maintained cold. It can be seen that it has been shortened. And
In spite of the shortening of the tundish (TD) rotation time, the quality of the slab is maintained at a high level, and the refractory cost and the tundish (TD) are lower than those in Comparative Example 1 in which cold repair is performed. ) Excellent results were obtained in terms of maintenance load. Further, in the case of Comparative Example 2 in which the residual steel slag was discharged from the tundish and then the nozzle maintenance was performed hot and continuous casting was continuously performed, the quality of the cast slab was significantly higher than in the embodiment. It turns out that the result is inferior.

[0027]

[Table 1]

The embodiment of the present invention has been described above.
The present invention is not limited to such an embodiment, and all changes in conditions that do not depart from the gist are within the scope of the present invention. For example, in this embodiment, a case where a boat-shaped tundish is used has been described, but the present invention can be applied to a box-shaped tundish or a tundish having an upper weir, a lower weir, and the like. Further, the present invention can be applied not only to the case where the number of nozzle refractories provided in the tundish is one set but also to the case where a plurality of nozzle refractories are installed.

[0029]

According to the method for reusing a tundish for continuous casting according to the first to sixth aspects, after the first continuous casting is completed, the residual steel slag is discharged from the tundish and then remains at the bottom. Since the remaining steel slag is removed by the remaining steel slag discharging means, the coating layer of the tundish is repaired, and the second continuous casting is started, the tundish maintenance work can be performed in a short time, and the operation rate of the tundish can be increased. And the damage to the nozzle refractory can be prevented. Further, since the heat loss due to cooling of the tundish is suppressed to a necessary minimum, the amount of heat required for preheating is reduced, and the tundish can be reused in a state of high thermal efficiency.

[0030] In the method for reusing a tundish for continuous casting according to claim 2, the residual steel slag is discharged from the tundish, and then, at least in some steps until the start of the second continuous casting. Since the refractory is kept warm, it is possible to reduce the thermal shock applied to the nozzle refractory and the surrounding refractory due to cooling during the repair work of the tundish.
In the method for reusing the tundish for continuous casting according to the third aspect of the present invention, when the residual steel slag is removed, it is particularly easy to remove the residual steel slag because it is locally cooled.
As a result, the residual steel slag is eliminated, and the quality of the cast product can be improved. In the method for reusing the tundish for continuous casting according to the fourth aspect, since the remaining steel slag, particularly the ingot, is removed with a pick or a stud, the deposit can be easily and reliably removed, and the contamination of the steel by the residue can be prevented. Can be prevented.

In particular, in the method for reusing a tundish for continuous casting according to the fifth aspect, since the temperature at the time of repairing the coating layer is within a specific range, oxidation of the ingot during maintenance of the tundish is suppressed. In addition to preventing the quality deterioration of the slab, the difference from the temperature at the time of reusing the tundish is kept small, the load of thermal shock applied to the lining refractory and the nozzle refractory is reduced, and the refractory Damage can be further suppressed. In the method for reusing a tundish for continuous casting according to the sixth aspect, the residual steel slag discharge means is a tilting device for the tundish or a residual steel slag discharge hole provided at the bottom of the tundish. Can be discharged more efficiently, and the productivity of continuous casting can be improved.

[Brief description of the drawings]

1 (a), (b) and (c) are a method for reusing a tundish for continuous casting according to an embodiment of the present invention, Comparative Example 1 performing cold repair, and hot repair, respectively. FIG. 9 is a flowchart of Comparative Example 2 for performing the following.

FIG. 2 is a side sectional view of a continuous casting facility to which the method for reusing a tundish for continuous casting is applied.

FIG. 3 is an explanatory diagram of a tundish after discharging residual steel slag.

FIG. 4 is an explanatory diagram of a tundish in a bullion collecting operation.

FIG. 5 is an explanatory diagram of a tundish during a repair work.

FIG. 6 is an explanatory diagram of a tundish during a preheating operation.

[Explanation of symbols]

Reference Signs List 10 continuous casting equipment 11 molten steel 12 ladle 13 long nozzle 14 tundish 15 nozzle refractory 16 mold 17 lining refractory 18 coating layer 19 upper nozzle 20 sliding nozzle 21 discharge hole 22 immersion nozzle 23 stud 24 burner 25 wire 26 simple burner 27 Spray nozzle 28 Residual steel residue

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F27D 1/16 F27D 1/16 Z

Claims (6)

[Claims] 1. A first continuous casting for injecting the molten steel into a mold through a nozzle refractory provided at the bottom of the tundish holding the molten steel to produce a slab, and then performing the tundish In the method for reusing a continuous casting tundish for performing a second continuous casting by removing residual steel slag such as molten steel, metal, slag, etc. in the tundish after completion of the first continuous casting, The residual slag is discharged using residual slag discharging means, and then the residual slag remaining at the time of discharging the residual slag of the tundish is removed and the tundish is repaired, and at least a part of the nozzle refractory is used. A method of reusing a tundish for continuous casting, wherein the second continuous casting is performed after the tundish is preheated by reusing. 2. The nozzle refractory is maintained in heat in at least a part of the steps of discharging the remaining steel slag in the tundish, removing the remaining steel slag, and repairing the tundish. Item 7. A method for reusing a tundish for continuous casting according to Item 1. 3. The method according to claim 2, wherein when removing the remaining steel residue from the tundish, the remaining steel residue is removed by forcibly cooling a part of the tundish. 3. The method for reusing the tundish for continuous casting according to 1 or 2. 4. The steel residue remaining at the time of discharging the steel residue from the tundish is removed by using a pick to remove the steel residue, or the metal fitting is welded to the steel residue and then the metal fitting is pulled to pull the metal fitting. The residual steel slag is removed.
4. The method for reusing the tundish for continuous casting according to any one of the above items 3. 5. The continuous casting tan according to claim 1, wherein the surface temperature of the coating layer applied during the repair of the tundish is 200 to 900 ° C. How to reuse the dish. 6. The residual steel slag discharging means is a tilting device for the tundish or a residual steel slag discharge hole provided in a bottom portion of the tundish. 2. The method for reusing the tundish for continuous casting according to item 1.