JPH09220647A - Tundish runway refractory for continuous casting - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To prevent continuous cracking of runner refractory used in a tundish for continuous casting, and to stably perform continuous casting many times for a long time without increasing furnace cost. To provide a tundish runway refractory for continuous casting. SOLUTION: The inside of a tundish 14 for continuous casting provided with an induction heating device 18 is arranged inside a weir 17 which divides a steel receiving portion 15 and a casting portion 16 into a steel receiving portion 15 and a casting portion 16. In the runway refractory 20 of the tundish 14 for continuous casting provided with the through holes 23 for connecting the runways, the runway refractory 20 has a thickness of 20 to 50 m with the inside having the pass holes 23.
It has an inner cylinder runner refractory 21 of m and an outer cylinder runner refractory 22 concentrically attached to the outside of the inner cylinder runner refractory 21 and having a thickness of 20 to 50 mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tundish runner refractory (also referred to as a gutter refractory on site) for continuous casting equipped with an induction heating device.

[0002]

2. Description of the Related Art A tundish for continuous casting receives and holds necessary components discharged from a ladle and molten steel whose temperature has been adjusted, and at the same time supplies molten steel to a continuous casting mold, It is a device that controls the amount of molten steel supplied to the continuous casting mold, makes the molten steel temperature uniform, and the like, and that floats and removes slag and inclusions in the molten steel. And
In the operation of such a tundish for continuous casting, control of the molten steel temperature in the tundish for continuous casting is a very important factor in terms of quality of the slab or removal of inclusions. Therefore, a method of directly heating the molten steel in the tundish for continuous casting using an induction heating device is adopted. The inside of a continuous casting tundish having such an induction heating device is divided into a steel receiving part and a casting part by a refractory weir, and as shown in FIG. 6 and FIG. Passage hole 5 of the provided runway refractory 51
The molten steel moves from the steel receiving portion to the casting portion through the second portion. At this time, an induction current is generated in the molten steel passing through the passage hole 52 by the induction heating device arranged around the passage hole 52, and the molten steel is directly heated by the Joule heat. And, for example, Japanese Utility Model Laid-Open No. 7-9548 discloses a runner having a tapered through hole that is reduced in one or more stages in the direction of the flow of molten steel in order to improve the efficiency of removing inclusions in the molten steel. A method of using a refractory material or a runway refractory material having flat elliptical hot water holes has been proposed.

[0003]

However, in the method for attaining a high degree of cleaning of molten steel by adjusting the hole shape of the runner refractory as described in Japanese Utility Model Laid-Open No. 7-9548, there is a problem in that Although the effect of floating inclusions is promoted, the amount of wear of the refractory becomes large because the flow velocity of the molten steel is accelerated in addition to the temperature change due to the induction heating of the molten steel passing through the through hole. As a result, the heat load on the runner refractory around the passage hole increases, cracks or wear increase in the runner refractory due to fluctuations in temperature and molten steel flow rate, and casting troubles occur, etc. However, there is a problem in that it is not stabilized, leading to a decrease in casting yield and a rise in the furnace material cost of the tundish for continuous casting. The present invention has been made in view of such circumstances, prevents cracking of the runway refractory used in the continuous casting tundish, without increasing the furnace material cost of the continuous casting tundish, An object of the present invention is to provide a tundish runner refractory for continuous casting, which enables stable continuous casting over a long period of time.

[0004]

According to the present invention, there is provided a semiconductor device comprising:
The runway refractory of the continuous casting tundish described, the inside of the continuous casting tundish equipped with an induction heating device,
A molten steel discharged from the ladle and a casting part for injecting the molten steel into a mold, and a hot water hole provided inside the weir for connecting the steel receiving part and the casting part. In a tundish runner refractory for continuous casting, the runner refractory has a thickness of 20 to 50 mm with a through hole inside.
Of the inner tube runner refractory, and an outer tube runner refractory having a thickness of 20 to 50 mm, which is concentrically mounted on the outer side of the inner tube runner refractory. A runner refractory for a continuous casting tundish according to claim 2 is the runner refractory for a continuous casting tundish according to claim 1, wherein each of the inner tubular runner refractory has a length of 400 mm or less. It is composed of a divided inner tube runner refractory having. A runner refractory for a continuous casting tundish according to claim 3 is the runner refractory for a continuous casting tundish according to claim 1 or 2, wherein the inner tube runner refractory and the outer tube runner refractory are included. A heat insulating material is provided between and.

The weir holds the runner refractory having a passage hole through which molten steel passes, and has an induction heating device for heating the molten steel passing through the passage hole. The contact wall is a partition wall of a continuous casting tundish made of refractory material. The induction heating device is a device that generates a low-frequency or high-frequency alternating magnetic field in molten steel and heats the molten steel by Joule heat of an induction current generated thereby. If the thickness of the inner tube runner refractory having the through hole and the thickness of the outer tube runner refractory arranged around the inner tube runner are less than 20 mm, respectively When the tube runner refractory material is melted or worn, it becomes difficult to maintain the minimum required mechanical strength. On the other hand, if the thickness of each of the above is greater than 50 mm, the temperature difference between the molten steel side flowing through the passage hole and the induction heating device side becomes large, resulting in excessive thermal stress and cracking of the runway refractory. It is not preferable because it causes
If the length of the divided inner tubular runner refractory that is divided in the direction of the through hole exceeds 400 mm, the thermal stress in the length direction exceeds the required limit due to the temperature rise of the molten steel passing through the through hole. However, cracks are likely to occur, which is not preferable. The heat insulating material means heat insulating mortar, ceramic paper made of an inorganic fiber such as alumina or mullite, or a combination thereof.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Next, referring to the attached drawings, an embodiment in which the present invention is embodied will be described to provide an understanding of the present invention. Here, FIG. 1 is a schematic explanatory view of a continuous casting facility 10 to which a runner refractory of a tundish for continuous casting according to an embodiment of the present invention is applied. As shown in the figure, the continuous casting facility 10 includes a ladle 11 that holds molten steel 13 and a long nozzle 1 that is arranged below the ladle 11.
2 has a tundish 14 for continuous casting that receives the molten steel 13 discharged through 2, and a mold 19 into which the molten steel 13 is injected through a dipping nozzle 25 provided in the lower part of the tundish 14 for continuous casting. . The tundish 14 for continuous casting has a steel receiving portion 1 of the molten steel 13 whose inside is discharged from the long nozzle 12 by a weir 17 made of refractory.
5 and a casting part 16 for supplying the molten steel 13 to the mold 19 from the immersion nozzle 25, and a runway refractory 20 having a through hole 23 inside the weir 17, and the through hole 23.
And an induction heating device 18 for heating the molten steel 13 passing through.

A ladle 11 holds molten steel 13 melted in a converter, a secondary refining furnace, etc., and a tundish 14 for continuous casting.
It is an iron container with a molten steel capacity of 350 tons, which is lined with an alumina-silica refractory or the like for pouring into. And
Molten steel 13 is introduced into a tundish 14 for continuous casting having a capacity of 40 tons through a long nozzle 12 made of alumina graphite and provided at the bottom of a ladle 11, and during this injection. It is possible to prevent the molten steel 13 from being oxidized or splashed. As the lining material of the continuous casting tundish 14, generally, a wax-like or chamotte-like brick with a small amount of metal is used, and a protective layer made of a magnesia coating material or the like is applied to a portion in contact with the molten steel 13. It is used to suppress the generation of non-metallic inclusions in the molten steel 13 due to the melting loss of the refractory that constitutes the continuous casting tundish 14. The weir 17 is made of a refractory material made of the same material as the lining material of the continuous casting tundish 14, and has a through hole 23 for guiding the molten steel 13 from the steel receiving portion 15 to the casting portion 16. The runner refractory 20 and the induction heating device 18 are arranged. FIG. 2 is a configuration explanatory view including the runway refractory 20 and a portion of the weir 17 in the periphery thereof, and FIG. 3 is a detailed explanatory view of the runway refractory 20. Where weir 1
Reference numeral 7 schematically represents the periphery, and the runner refractory 20 has an inner tubular runner refractory 21 having a through hole 23 and an outer tubular runner refractory 22 arranged around the inner runner refractory 21. It shows how it is configured. In addition, the runway refractory 20 is the same weir 17
When a plurality of runner refractory materials 20 are arranged in parallel, an induction coil of the induction heating device 18 is provided between the two runner refractory materials 20,
The molten steel 13 flowing through the passage hole 23 can be efficiently heated.

The inner tube runner refractory 21 has an inner diameter of 100 mm, a thickness of 20 mm, and a total length of 120, which is used as a passage hole 23.
It has a cylindrical shape of 0 mm, and its total length is 150 mm, 300
mm, 300 mm, 300 mm, and 150 mm, which are divided into inner tubular runner refractories 21a to 21e. The divided inner tubular runner refractories 21a to 21e can be made of refractory having high thermal shock resistance such as alumina-silica or alumina graphite. The outer tube runner refractory 22 has the inner tube runner refractory 21 inserted in its inner portion, and has a thickness of 20 mm and a total length of 1200 mm.
It has a cylindrical shape with a total length of 40 mm, 280 mm, 2
It is composed of divided outer tube runner refractories 22a to 22e which are divided into lengths of 80 mm, 280 mm, 280 mm, and 40 mm, respectively. The outer tube runner refractory 22 may be made of the same material as the inner tube runner refractory 21, or may be made of chamotte, wax stone, or the like. Then, as shown in FIG. 3, the inner tube runner refractory 21 divided in the length direction,
The outer joint runner refractory 22 and the outer joint runner refractory 22 are arranged so that their respective joint surfaces do not overlap each other. As a result, even if the molten steel 13 penetrates deeply into the joint surface between the inner tube runner refractory 21 from the through hole 23 side, it can be securely stopped by the inner wall surface of the outer tube runner refractory 22 and can be used safely. Therefore, the thermal stress generated between them can be relaxed.

Further, a plurality of outer tube runner refractories 22 are arranged around the outer tube runner refractory 22 to further reduce the thermal stress and to replace the outer tube runner refractory 22. It can also be easy. In addition, a heat insulating material is arranged in advance in the circumferential joint between the inner tube runner refractory 21 and the outer tube runner refractory 22, and the inner tube runner refractory 21 and the outer tube runner refractory 21 are disposed in advance. It is designed to reduce the thermal shock of 22. Further, the heat insulating material can be arranged between the outer tube runner refractory 22 and the weir 17, and when the outer tube runner refractory is concentrically mounted by a plurality of cylindrical sleeves, Insulation can also be placed between the cylindrical sleeves. Here, as the heat insulating material, the one in which a heat insulating mortar 24 having a thickness of 1 to 5 mm is applied to the joint is used, but instead of the heat insulating mortar 24, a fire resistant ceramic paper or the like made of an inorganic fiber may be used. The immersion nozzle 25 is a substantially cylindrical refractory material made of alumina graphite, and the molten steel 13 is injected into the mold 19 through the discharge holes 26 of the molten steel 13 at the bottom to stabilize the meniscus surface of the molten steel 13 on the mold 19. Play the role of forming. The induction heating device 18 generates a high-frequency or low-frequency alternating magnetic field in the molten steel 13 passing through the molten metal hole 23, and directly heats the molten steel 13 with Joule heat of an induction current generated with the variation of the magnetic field. It is a device.

In the conventional runner refractory, the shape of the through hole is set from the viewpoint of cleanliness of molten steel, and the thickness of the cylindrical runner refractory is set from the viewpoint of wear rate. In the runner refractory 20 of the tundish for continuous casting according to the embodiment of the present invention, in the cylindrical structure of the runner refractory 20 which is subjected to a severe heat cycle load, the magnitude of the thermal stress caused by the heat cycle is determined. By calculating, evaluating, or experimentally obtaining, conditions of the runner refractory 20 that do not induce cracks due to such thermal stress are set, and the occurrence of cracks is suppressed and stable for a long time. It enables continuous continuous casting. Generally, when an object is heated, microelements of the object try to thermally expand according to the temperature at that point, and if this thermal expansion is hindered for some reason, stress called thermal stress is generated in the object. When a temperature difference (ΔT) occurs in the outer diameter portion of the cylindrical runner refractory 20, tensile thermal stress (σ) occurs inside the refractory. In the case of a cylindrical shape, the basic equation of thermal stress in an axisymmetric field can be applied, and the tensile stress (σ) can be calculated using, for example, equation (1) shown below. σ = {E · α · ΔT / (1-ν)} · {1 / (2 × Ln (b-a)) - a 2 / (b 2 -a 2)} ·· (1) Incidentally, E, α, ν, ΔT, a, and b are the elastic modulus, the thermal expansion coefficient, the Poisson's ratio, the temperature difference between the inner and outer diameter portions, the outer diameter, and the inner diameter, respectively, of Lun (x). number:
It represents the natural logarithm for x.

It is also possible to experimentally measure the magnitude of the thermal stress applied to the runner refractory 20 under the set temperature condition, without using the above-mentioned basic formula.
For example, the temperature difference between the inner diameter surface and the outer diameter surface of the cylindrical runner refractory 20 is controlled to be a predetermined temperature difference, and the strain amount or stress value at each part generated at this time is calculated as follows. The thermal stress value may be evaluated by directly measuring with a means such as a load cell or a strain gauge, and converting this value into a temperature condition during actual use. further,
The temperature of each part of the runner refractory 20 during actual use is measured or predicted, and the thermal stress generated in each part of the runner refractory 20 is calculated or predicted based on this temperature distribution data. It is also possible. The relationship between the tensile stress (σ) obtained based on these theoretical consideration or experimental data and the shape factor of the runway refractory 20 is shown in FIGS. 4 and 5. Here, in FIG. 4, the diameter (ie, inner diameter (b)) of the through hole 23 of the inner tube runner refractory 21 is set to a predetermined 100 mm, and the outer diameter (a) is made different, so that the thickness (a It is an example of the data which prepared the thing which changed -b) in the range of 10-60 mm, and calculated | required the value of the tensile stress which arises when the temperature difference ((DELTA) T) of an outer diameter part is set among this. . The value of ΔT can be measured by using the temperature of the thermocouple or the molten steel 13 actually buried in the runway refractory 20.

Further, such a value of ΔT is different between the value at the time of preheating of the continuous casting tundish 14 before casting and the value at the time of casting, corresponding to the history of the heat load received. Using the measured value of ΔT, the outer diameter (a) and the inner diameter (b) of the inner tube runner refractory 21,
The corresponding tensile stress data can be calculated by the equation (1). In addition, here, the inner tube runner refractory 2
As the values of the elastic modulus, the coefficient of thermal expansion, and the Poisson's ratio of 1, the general values of the alumina-silica refractory applied here were applied. As shown in FIG. 4, the tensile stress (σ) increases as the thickness (ab) increases at both preheating (●) and casting (∘), and the thickness (ab) is 50 mm. It can be seen that there is a tendency for the number to increase sharply beyond. This tendency is larger in the casting stage than in the preheating stage.
Thickening of more than mm is inappropriate. Further, according to the experimental results of the present inventors, the level of the limit tensile stress that induces cracks in such an alumina-silica refractory is 20.
It is known that the inner pipe runner refractory 21 has a thickness (ab) of 50 mm or less, and it is known that the heat load in the operation using the induction heating device 18 is Mpa to 30 Mpa or more. It can be seen that it is desirable to avoid the effect of.

Further, FIG. 5 shows that the diameter of the through hole 23 of the inner tube runner refractory 21, that is, the inner diameter (b) is set to a predetermined value of 100 mm.
Moreover, the outer diameter (a) was set to 140 mm, the thickness (ab) was set to 20 mm, the total length was changed, and the value of the tensile stress generated at that time was calculated. This is an example. The temperature difference between the inner and outer diameter parts (Δ
As the data of T), data experimentally measured separately can be used. As is clear from the figure, the tensile stress (σ) increases with increasing length both during preheating (●) and during casting (○). When the length exceeds 400 mm, the tensile stress (σ) increases. The value of) is 20Mp, which is the limit point for the crack induction of refractory materials.
It can be seen that the level exceeds a. Therefore, if the length exceeds 400 mm, the runner refractory 20 tends to induce circumferential or axial cracks during preheating or casting. Further, as can be seen from the equation (1), it is also possible to suppress the induction of cracks by installing a heat insulating material on the outer surface of the runner refractory 20 and reducing the temperature difference ΔT between the inner and outer surfaces. At this time, as the heat insulating material to be used, ceramic paper having an appropriate thickness, heat insulating mortar 24, etc. are used between the inner tube runner refractory 21 and the outer tube runner refractory 22 or between the runner refractory 20 and the weir 17. It is desirable to intervene between them. Based on the results of these examinations, the inner tube runner refractory 21 or the outer tube runner refractory 22 was formed with a thickness of 10 to 50 mm and a length of 400 mm.
The present invention proposes a tundish runner refractory for continuous casting, which can suppress the generation of thermal stress to a minimum by using a multilayered structure having a cylindrical shape of mm or less.

Next, a continuous casting method in which the runway refractory for continuous casting tundish according to the embodiment of the present invention is applied to the continuous casting facility 10 will be described. First, weir 17
The runner refractory 20 is set in a multi-layered state as shown in FIGS. Next, tundish 1 for continuous casting
4 After covering the upper opening with a tundish cover (not shown), a flame is blown into the tundish 14 for continuous casting by a gas burner or the like so that the steel receiving portion 15,
And, the inside of the continuous casting tundish 14 including the casting portion 16 is preheated. During this period, the induction heating device 18 is not in the operating state, but since the high-temperature flame passes through the through hole 23 of the runner refractory 20, the inner tubular runner refractory 21 and the outer tubular runner refractory 2
The temperature difference of the outer diameter of each of the two increases sharply. However, since the runner refractory 20 is divided into small portions, excessive thermal stress does not occur, and the occurrence of cracks and the like is suppressed. Then, the molten steel 13 is poured into the steel receiving portion 15 of the continuous casting tundish 14 from the ladle 11 which holds 350 tons of the molten steel 13. This molten steel 13
While flowing into the casting portion 16 through the passage hole 23 of the runway refractory 20 and operating the induction heating device 18 to heat the molten steel 13 to a required temperature level. Therefore, due to such heat load, the temperature in the inner diameter portion and the outer diameter portion of the runner refractory 20 fluctuates, and thermal stress is generated.

The molten steel 13 is heated by the induction heating device 18 while passing through the passage hole 23, and is discharged as a high-temperature molten steel flow to the casting portion 16 side of the continuous casting tundish 14. Therefore, due to the difference in specific gravity between the molten steel 13 in the casting portion 16 and the hot molten steel 13 just discharged, and the momentum of the discharged molten steel flow, the continuous casting tundish 14
A flow is generated toward the upper surface of the molten steel 13. Therefore,
The nonmetallic inclusions floating in the molten steel 13 are floated on the surface of the molten steel 13, and the cleaning effect of the molten steel 13 is further promoted.
Then, when the molten steel 13 in the continuous casting tundish 14 reaches a predetermined molten metal level and reaches the required temperature and cleanliness level, the mold 19 is passed through the immersion nozzle 25.
Discharge (casting) to. A molten steel flow rate control such as a sliding nozzle (not shown) provided between the continuous casting tundish 14 and the dipping nozzle 25, between the ladle 11 and the long nozzle 12, or a stopper device arranged above the continuous casting tundish 14. Using the apparatus, continuous casting is carried out while maintaining the required level of molten steel 13 and the drawing speed of the cast piece cast through the mold.

When the molten steel 13 in the ladle 11 is completely discharged into the continuous casting tundish 14, the ladle 11 is replaced with the next waiting ladle 11, and the continuous casting tundish 14 is discharged. Can be repeated continuously. Thus, as the number of heats that can be continuously cast in the same continuous casting tundish 14 while the ladle 11 is replaced is increased, the continuous casting operation with a lower furnace material cost can be performed, but the runway refractory 20 If the life of the inner tube runner refractory 21 is shortened, the cost of the furnace material required for this continuous casting operation will increase. In the present embodiment, the ladle 11 is exchanged for three times and the first heat continuous casting is completed. Next, the tundish 14 for continuous casting is transferred to a repair yard, discharged, and the metal is dropped to cool it.
Repair work such as replacement of the immersion nozzle 25 and application of coating material was performed. The temperature change of the runner refractory 20 due to cooling during this period is large, and therefore the thermal stress generated is also high, but even in this case, the runner refractory 20 is divided into small parts so as to suppress such thermal stress. Therefore, it is possible to effectively prevent the occurrence of cracks due to thermal stress.

After repairing the tundish 14, the continuous casting tundish 14 was again preheated as described above and the continuous casting was started as described above. Thus, in the present embodiment, 3 heats (3 times + 4 times + 3
It has been possible to repeatedly perform continuous casting) times. At this point, when the runner refractory 20 was removed from the weir 17 of the continuous casting tundish 14 and observed in detail, both the inner tube runner refractory 21 and the outer tube runner refractory 22 did not have cracks,
The metal insert around the passage hole 23 was not recognized, and it was in a good state. Incidentally, the undivided integrated runner refractory 51 in the conventional example shown in FIG. 7 was treated under the same conditions as in the present embodiment, and was removed and observed.
Due to the cracks at three locations and the ingots at three locations, the durability was equivalent to six ladle changes, but in the present embodiment, the inner tube runner refractory 21 was used ten times or more, and With respect to the tube runner refractory 22, it was possible to significantly extend the service life of 15 times or more. In the conventional runway refractory 51, the inner diameter of the hot water passage hole 52 is 100.
An alumina-silica refractory having a thickness of 50 mm, a thickness of 50 mm, and a length of 1200 mm was used. Table 1 shows a tundish runway refractory 20 for continuous casting according to an embodiment of the present invention.
Each of the data of the case of using the above and the case of using the runner refractory 51 according to the conventional example were compared with the test results by the continuous casting.

[0018]

[Table 1]

It can be seen that in the present embodiment, as compared with the long runner refractory 51 having the single-layer structure of the conventional example, there is no generation of cracks or metal ingots and the durability is nearly doubled. In this way, the inner tube runner refractory 21 is less damaged and can be repeatedly used up to 3 heats or more. Therefore, the load applied to the outer tube runner refractory 22 arranged on the outer periphery thereof via the heat insulating material is also reduced, and the furnace material cost can be reduced. Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and changes in conditions and the like without departing from the gist are all within the scope of application of the present invention. For example, in the present embodiment, a cylindrical sleeve having a single-layer structure is used as the outer tube runner refractory, but the outer tube runner refractory has a multi-layered structure composed of, for example, 2 to 4 layers to further improve heat resistance. Since the stress can be relaxed and the exchanging part can be limited to the damaged part when exchanging the runner refractory, the cost of the furnace material can be further reduced.
Further, in the present embodiment, the outer tube runner refractory is divided into a plurality of holes in the direction of the through hole, but it is also possible to form a jointless integral structure without dividing it. This makes it easy to replace runner refractories when repairing a continuous casting tundish.

[0020]

In the tundish runner refractory for continuous casting according to any one of claims 1 to 3, the runner refractory has an inner tube runner refractory having a thickness of 20 to 50 mm with through holes inside. And the outer cylinder runner refractory having a thickness of 20 to 50 mm, which is concentrically mounted on the outer side of the inner cylinder runner refractory, and has a thickness of 20 to 50 mm. The thermal stress generated by heating can be reduced, and the thermal stress can be effectively dispersed and maintained within a low level where the refractory does not crack. As a result, the continuous casting tundish equipped with an induction heating device can be operated without causing metal ingots or molten steel leaks, ensuring the safety of refractory materials and ensuring stable continuous casting. In addition, the cleanliness of molten steel can be ensured without increasing the cost of the furnace material. It is also possible to further reduce the furnace material cost by replacing and reusing only the inner tube runner refractory.

In particular, in the tundish runner refractory for continuous casting according to claim 2, the inner tubular runner refractory is composed of divided inner tubular runner refractories each having a length of 400 mm or less. As a result, the level of thermal stress generated in the runner refractory can be further reduced, which can further improve operational stability and reduce furnace material cost. Further, in the runner refractory of the continuous casting tundish according to claim 3, since the heat insulating material is provided in the circumferential joint between the inner tubular runner refractory and the outer tubular runner refractory, the The temperature difference between the outer diameter portion and the inner diameter portion of the runner refractory can be reduced, and the thermal stress during continuous casting can be further lowered.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a continuous casting facility to which a runway refractory for a tundish for continuous casting according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory view of a runner refractory of the continuous casting tundish and its surroundings.

FIG. 3 is a detailed view of a runway refractory of the tundish for continuous casting.

FIG. 4 is a diagram showing the relationship between the thickness of a runner refractory and tensile stress.

FIG. 5 is a diagram showing the relationship between the length of a runner refractory and tensile stress.

FIG. 6 is an explanatory view of a runway refractory of a tundish for continuous casting according to a conventional example and its surroundings.

FIG. 7 is a detailed view of a runway refractory of the continuous casting tundish.

[Explanation of symbols]

10 Continuous casting equipment 11 Ladle 12 Long nozzle 14 Tundish for continuous casting 13 Molten steel 15 Steel receiving part 16 Casting part 17 Weir 18 Induction heating device 19 Mold 20 Refractory runner 21 Inner tube runner refractory 21a Split inner tube hot water Road refractory 21b Divided inner cylinder runner refractory 21c Divided inner cylinder runner refractory 21d Divided inner cylinder runner refractory 21e Divided inner cylinder runner refractory 22 Outer cylinder runner refractory 22a Divided outer cylinder runner refractory 22b Divided outer tube runner refractory 22c Divided outer tube runner refractory 22d Divided outer tube runner refractory 22e Divided outer tube runner refractory 22f Divided outer tube runner refractory 23 Passage hole 24 Insulating mortar 25 Immersion nozzle 26 Discharge hole

Claims (3)

[Claims] 1. A weir that divides the inside of a continuous casting tundish equipped with an induction heating device into a steel receiving portion for molten steel discharged from a ladle and a casting portion for injecting the molten steel into a mold. Arranged, in the runway refractory of the continuous casting tundish provided with a throughhole that connects the steel receiving part and the casting part, the runway refractory, the thickness of the inside is the throughhole 20 ~
A continuous structure comprising a 50 mm inner cylinder runner refractory and an outer cylinder runner refractory having a thickness of 20 to 50 mm concentrically attached to the outside of the inner cylinder runner refractory. Tundish runway refractory for casting. 2. The inner tube runner refractory is 40
The tundish runner refractory for continuous casting according to claim 1, wherein the runner refractory is a divided inner tubular runner refractory having a length of 0 mm or less. 3. A tundish runner refractory for continuous casting according to claim 1, wherein a heat insulating material is provided between the inner barrel runner refractory and the outer barrel runner refractory. Stuff.