JP2015221456A - Weir refractory construction method for induction heating type tundish and weir refractory repair method for weir refractory - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the generation of cracks with complicating the configuration of the whole of a weir refractory.SOLUTION: A method of the invention is the method for applying a weir refractory 11 to an induction heating type tundish 1 provided with the weir refractory 11 having channels 12a that make molten steel pass through in both side bottoms in the width direction between the hot-water receiving side 2 that receives molten steel from a ladle and the casting side 3 that discharges the molten steel into the casting mold. Firstly, castable refractories 13,14 are cast into the periphery of a coil duct 5 to make an iron core for induction heating pass through to apply a castable refractory layer. Next, after block refractories 16-18 are disposed on the side of the runner refractory 12 of the castable refractory layers 13,14 and on the side of the hot-water receiving side 2 and the casting side 3 on the utilization side of the castable refractory layers 13,14, a castable refractory 15 is applied to a gap between these block refractories 16-18 and between a runner brick 12 and the castable refractory layers 13,14.

Description

  The present invention relates to a method for constructing a weir refractory for an induction heating type tundish, and a method for repairing a weir refractory constructed by this method.

  In continuous casting, an induction heating type tundish equipped with an induction heating iron core is used for the purpose of separating floating of inclusions in molten steel supplied to a mold and distributing the molten steel to a plurality of molds.

  As shown in FIG. 5, this induction heating type tundish 1 includes a hot water receiving side 2 into which molten steel is poured from a ladle, and a casting side 3 for discharging molten steel in the tundish 1 from a discharge hole 3a to a mold. It is partitioned by a large weir refractory 4. When the molten steel passes from the hot water receiving side 2 to the casting side 3 through the flow path 4a formed in both lower portions in the width direction of the weir refractory 4 (the vertical direction in FIG. 5A), the weir refractory The object 4 is configured to be heated by an induction heating iron core provided between the two flow paths 4a.

  When the large weir refractory 4 is viewed from above the tundish when it is installed in the tundish, as shown in FIG. 6, the hole 5a of the coil duct 5 through which the induction heating iron core is passed, The surroundings are formed by combining a plurality of types of refractories such as the shaped brick 6 and the block refractory 7. In addition, 8 in FIG. 6 shows a runner refractory.

  Weir refractories with such a structure cause cracks in the refractory and / or the opening of joints between bricks due to the effects of heating, cooling and vibration in the process of repeatedly reusing the tundish. Cracks and joints gradually develop, eventually reaching the metal bar, making repair difficult. Therefore, the weir refractory is dismantled at the stage of reaching the metal bar, which is expensive in terms of cost.

  Therefore, when a large dam refractory is formed, there is a problem that the cost is high. In addition, when a large amount of amorphous refractory is poured during construction to increase the construction thickness, it takes a long time to dry the refractory, so that the construction time of the weir refractory becomes long.

  On the other hand, when constructing a dam refractory by combining a plurality of types of refractories, there is a problem that the construction work becomes complicated and individual differences in construction accuracy occur among construction workers.

  In the following, the regular refractory (or regular brick) means a refractory that has been molded and fired in advance, and the irregular refractory means a granular or kneaded refractory. In addition, the block refractory means an indeterminate refractory that is usually poured in on-site construction, and is a refractory that has been molded and dried in advance.

  In view of the above-mentioned problem of the induction heating type tundish, Patent Document 1 discloses a block body in which a refractory sleeve that forms a flow path that communicates a hot water receiving side and a casting side is formed into a fixed shape using a different kind of irregular refractory. A method of disposing and integrating sleeve bricks manufactured in advance by interposing an expansion-absorbing refractory material at a predetermined position is disclosed.

  According to the method disclosed in Patent Document 1, it is possible to prevent cracks from occurring in the sleeve brick and the block body, but it is possible to prevent ingots in other constituent parts of the dam refractory. There is no mention.

  Further, in Patent Document 2, the tip of the presser member attached and fixed inside the tundish iron skin is embedded in either or both of the refractory and the refractory upper surface constituting the dam refractory, A method of suppressing the occurrence of cracks in the weir refractory and the loosening of the refractory is disclosed.

  However, this Patent Document 2 also does not mention mentioning suppression of cracks generated based on the structure of the dam refractory.

  Further, Patent Document 3 discloses a tundish runway refractory in which an outer tubular runway refractory is concentrically mounted on the outside of an inner tubular runway refractory whose inner side is a flow path of molten steel. Things are disclosed.

  The runner refractory disclosed in Patent Document 3 does not cause excessive thermal stress even if the temperature of the inner tubular runner refractory and the outer tubular runway refractory increases rapidly during preheating. Moreover, since the thermal stress for heating and cooling when the tundish is repeatedly reused can be suppressed, it is possible to prevent the runway refractory from cracking.

  However, the runner refractory disclosed in Patent Document 3 is divided into an inner tubular runway refractory and an outer tubular runway refractory because the runner refractory is divided into an outer tubular runway refractory and a loose joint. There is a problem in that there are many places where bullion is generated. Moreover, there is no description which mentions preventing the metal bar in the component part of dam refractories other than runner refractories.

Japanese Patent No. 3205119 Japanese Patent No. 5075651 JP-A-9-220647

  The problem to be solved by the present invention is that the techniques disclosed in Patent Documents 1 to 3 suppress cracks generated based on the structure of the dam refractory, and other than sleeve brick and block body or runway refractory. It is a point that there is no description which mentions preventing the metal bar in the component part of a dam refractory. That is, the technique disclosed in Patent Documents 1 to 3 is a partial improvement of the weir refractory.

  The object of the present invention is to reduce the metal insert by improving the overall refractory structure and dam structure of the dam refractory.

  Specifically, the present invention suppresses the generation of cracks without complicating the overall construction of the dam refractory, thereby reducing the construction time without increasing the construction time. The goal is to prevent differences.

The present invention
A hot water receiving side for receiving molten steel from a ladle, a casting side for discharging molten steel into a mold, and a flow path for passing molten steel from the hot water receiving side to the casting side between the hot water receiving side and the casting side in the width direction The induction heating type tundish provided with the dam refractory provided on the lower sides of the both sides is a method of constructing the dam refractory,
First, a plurality of amorphous refractory layers are constructed by pouring an amorphous refractory around the coil duct for passing the induction heating iron core,
Next, the runner refractory that forms the flow path is placed on the lower side of the weir refractory in the width direction of the enforced amorphous refractory layer, and the block refractory is provided with a plurality of irregular refractory layers. After arranging the runner refractory side and the plurality of irregular refractory layers on the hot water receiving side of the runner refractory and the working surface side of the casting side, the block refractory and the runway brick and the plurality The most important feature is the construction of an amorphous refractory in the gap with the amorphous refractory layer.

  The dam refractory construction method of the present invention is constructed using a large dam refractory using a runway refractory, an irregular refractory, and a block refractory, and eliminates the need for shaped brickwork. The overall configuration is not complicated, and the number of joints between bricks is greatly reduced. Moreover, since many block refractories are used, the construction amount of an amorphous refractory can be reduced even if it is a large dam refractory. Moreover, since a block refractory is constructed outside the plurality of irregular refractory layers, the progress of cracks can be suppressed.

The present invention also provides:
A method for repairing a weir refractory of an induction heating type tundish constructed by the method of the present invention,
Installed in the gap between the block refractory and multiple amorphous refractory layers from the working side of the hot water receiving side and casting side of the runway refractory by the thickness that can collect the block refractory constructed on the working side. After dismantling the irregular refractory and taking out the block refractory,
The repaired block refractory, which has been repaired from the removed block refractory, is placed on the hot water receiving side of the runway refractory and on the working side of the casting side, and in the gap between the repaired block refractory and a plurality of irregular refractory layers. The most important feature is that it is poured into an irregular refractory.

  The dam refractory repair method of the present invention collects the block refractory at the time of dismantling the dam refractory and uses it again for repair on the working surface side, so the amount of construction of the irregular refractory constructs the entire weir refractory Small amount compared to the case.

  In the construction method of the present invention, a large dam refractory is composed of a runway refractory, an irregular refractory, and a block refractory, so that no fixed brickwork is required, so the overall structure of the dam refractory is complicated. Therefore, individual differences among construction workers can be reduced. In addition, since no regular brickwork is required, the number of joints between bricks is greatly reduced, and joints between bricks are not opened. Moreover, since many block refractories are used, even if it is a large dam refractory, the construction amount of an amorphous refractory can be reduced and the moisture drying contained in a refractory can also be performed easily. Moreover, since a block refractory is constructed outside the plurality of irregular refractory layers, the progress of cracks can be suppressed.

  In addition, the repair method of the present invention collects the block refractory at the time of dismantling the dam refractory, and again uses it for repair on the working surface side, so when the construction amount of the irregular refractory applies the entire dam refractory Compared to a small amount. Therefore, the cost of the dam refractory that has been expensive can be improved, and the moisture drying time of the refractory can be shortened when the dam refractory is repaired.

  That is, according to the present invention, it is possible to suppress the bullion insertion to the dam refractory of the induction heating type continuous casting tundish, so that it is possible to establish a planned dam refractory repair construction, Can stop the use of tundish, and can improve the life of the weir until the entire weir refractory is dismantled.

It is explanatory drawing of the dam refractory constructed by the method of this invention, (a) is the side view seen from the hot water receiving side of the tundish, (b) is AA sectional drawing of (a), (c) is ( It is BB sectional drawing of a). It is sectional drawing of the BB position of Fig.1 (a) of the dam refractory repaired with the method of this invention. It is the figure which compared the weir refractory construction cycle of the tundish by the conventional method and the method of this invention, and the weir life. It is the figure which compared the moisture drying time index | exponent after repair of the tundish weir refractory by the conventional method and this invention method. It is a figure explaining the tundish for induction heating type | mold continuous casting, (a) is the figure seen from upper direction, (b) is EE sectional drawing of (a). It is sectional drawing in the BB position of Fig.1 (a) of the dam refractory constructed by the conventional method.

  The purpose of the present invention is to suppress the occurrence of cracks without complicating the overall structure of the dam refractory, to prevent the construction time from becoming long, and to prevent individual differences among construction workers in construction accuracy. It is what.

  In order to stabilize the weir refractory of the induction heating type tundish and to improve the cost by improving the lifespan, it is necessary to suppress the bare metal insertion due to the crack propagation which has been a problem until now.

  As a result of the inventor observing and analyzing the generation process of the bullion, the joints between the bricks constituting the weir refractory loosen due to heating, cooling and vibration by repeated reuse of tundish, and irregular refractories. It was found that the cracks of the metal gradually developed and a bullion was generated.

  Based on these considerations, the weir refractory of the induction heating type tundish eliminates joint joints between bricks or eliminates joints, thereby eliminating joint loosening due to vibration. Moreover, we thought that the progress of cracks could be suppressed by constructing a layered amorphous refractory around the coil duct and constructing a block refractory.

Therefore, in order to realize the above object, the inventor decided to adopt the following configuration.
1) In order to greatly reduce the number of joints between bricks, a large number of irregular refractories and block refractories will be used to eliminate the need for regular brickwork.

2) In order to suppress the growth of cracks, a layer of amorphous refractory is applied around the coil duct.
further,
3) In order to reduce individual differences among construction workers, it is composed of runner refractories, irregular refractories, and block refractories, so that there is no need for regular brickwork and no complicated construction.

In the case of a dam refractory constructed by the method of the present invention,
4) Block refractories can be recovered at the time of dismantling the weir refractories and used again for the construction of weir refractories, so that the working surface can be partially dismantled and repaired.

5) Since the repaired weir refractory reduces the amount of non-standard refractory construction, moisture drying is easy even for large weir refractories.
6) By these, it is possible to prevent the use of the dam refractory due to sudden bullion insertion, and to make planned tundish construction possible. In addition, the cost of the dam refractory is improved.

  Hereinafter, a method of constructing a weir refractory by the method of the present invention on the induction heating type tundish 1 described in FIG. 5 will be described with reference to FIG.

  11 is a weir refractory constructed by the method of the present invention, such as a runner refractory 12, a three-layer amorphous refractory 13 to 15 constructed around a coil duct 5 of an induction heating iron core, It consists of block refractories 16-18 constructed on the outer peripheral side of the irregular refractories 13-15 of the layer, eliminating the need for conventional shaped brickwork.

  When the dam refractory 11 is constructed, first, for example, the amorphous refractories 13 and 14 are poured around the coil duct 5 through which the induction heating iron core is passed to form two layers of the irregular refractory layers. Install.

For example, the casting of the irregular refractories 13 and 14 is performed as follows.
First, an outer frame having a first layer thickness, for example, a gap of 30 mm, is arranged on the outer periphery of the coil duct 5, and then the amorphous refractory 13 is injected into the gap, and then solidified and then the first layer outer frame. Remove. Next, an outer frame having a second layer thickness, for example, a gap of 30 mm, is disposed on the outer periphery of the first layer, and the second layer of the amorphous refractory 14 is injected. After the second-layer amorphous refractory 14 is solidified, the outer frame of the second layer is removed.

  Next, the runaway refractory 12 having a flow passage 12a formed therein is used for flowing molten steel from the hot water receiving side 2 to the casting side 3 of the tundish 1 shown in FIG. The tundish 1 is disposed at the lower part on both sides in the width direction.

  Further, the runway refractory of the unstructured refractory 13 and 14 layer having the block refractory 17 constructed between the unstructured refractory 13 and 14 layer having the block refractory 16 constructed and the runway refractory 12 has been constructed. The block refractory 18 is disposed above the block refractory 16 on the hot water receiving side 12 and the working side of the casting side.

  Thereafter, an outer frame is formed by forming a gap of, for example, 50 mm on the hot water receiving side and the casting side working surface side of the runner refractory 12, and the block refractories 16 to 18 and the runner brick 12 The amorphous refractory 15 is applied in the gap between the amorphous refractory 13 and 14 layers.

  In the above-mentioned method of the present invention, the construction of the irregular refractory layer is also restricted due to the restrictions on the equipment, but in general, the ladle refractory has two layers of permanent bricks and one layer of ware refractory as a standard total of three layers. Therefore, also in the case of the weir refractory 11 of the present invention, it is desirable that the number of layers formed by casting the irregular refractory is three or more. In the case of the present invention, since the block refractory 16 or 18 is installed on the side of the coil duct 5 of the runner refractory 12, it can be said that it is substantially a four-layer structure.

  The thickness of the irregular refractories 13 to 15 to be cast is such that the casting is possible, the filling property of the cast irregular refractories 13 to 15 can be ensured, and the effect of suppressing the progress of cracks is achieved. To do. However, at least 30 mm is necessary even within the set restrictions on equipment.

  Moreover, the strength of the irregular refractories 13 to 15 to be cast may be different from each other. The strength of the amorphous refractory varies depending on the material characteristics. Therefore, if you want to increase the strength, for example, add stainless steel fiber to the material to reduce the amount of water added and reduce the porosity (densification). Good. In addition, the strength can be changed by changing the material particle size, improving the binder, and the like. However, when the thickness is 30 mm as in the above embodiment, it is necessary to select a material having fluidity in consideration of the filling property of the selected material.

  In the dam refractory 4 constructed by the conventional method described in FIG. 6, including the combination of the regular bricks 6, the casting of the irregular refractory is carried out, but the progress of the crack and the opening of the joints between the regular bricks 6 are performed. The ingot generated by the intrusion into the inside of the weir refractory 4. Therefore, it is difficult to repair the weir refractory 4 and it is necessary to dismantle all of the weir refractory.

  However, in the present invention, the joint between bricks is greatly reduced by eliminating the need for regular brickwork, and the refractories 13 to 15 and the block refractories 16 to 18 are combined and applied in layers. By forming, the crack stops between each layer of the refractory, and its progress is suppressed.

  Due to these effects, the dam refractory 11 constructed by the method of the present invention has a structure in which a bullion does not penetrate into the interior even when a bullion is inserted, and bullion removal and periodic repair work are possible. .

  Moreover, since it is comprised with the runway refractory 12, the unshaped refractories 13-15, and the block refractories 16-18, regular brickwork will become unnecessary and it can reduce the individual difference of a construction worker.

  Moreover, what is necessary is just to repair the weir refractory 11 constructed by the said method of this invention as follows.

  First, from the working surface of the runner refractory 12 on the hot water receiving side and the casting side, the thickness of the block refractory 17 constructed on the working surface side can be recovered, for example, the CC line shown in FIG. And, from the DD line to the working surface, for example, about 100 mm, the irregular refractory 15 is disassembled, and the block refractory 17 is taken out and collected.

  Next, the repaired block refractory 19 obtained by repairing the taken out block refractory 17 is arranged on the hot water receiving side of the runway refractory 12 and the working surface side of the casting side, and the repaired block refractory 19 and the unshaped refractory. The refractory material 20 is poured into the gap between the 13th and 15th layers for construction.

  FIG. 2 shows a cross-sectional view of the weir refractory 11 after repair at the position B-B in FIG. 1 (a). By the construction with the irregular refractory 20 and the repair block refractory 19, the irregular shape used for repair construction is shown. The construction amount of the refractory 20 can be reduced, and moisture drying can be easily performed even in the large dam refractory 11.

  From these, the repair construction of the dam refractory 11 is established, the cost can be improved by improving the life until the entire surface of the dam refractory 11 is disassembled, The use of the tundish can be continued without stopping, and the tundish construction process can be systematically performed.

The effect of the present invention is shown in FIGS.
As shown in FIG. 3, the dam refractory composed of a conventional refractory casting process including a combination of regular bricks disassembles the dam refractory with the average number of uses of 10 heats.

  On the other hand, in the present invention, the dam refractory can be repaired on the way, and as shown in FIG. 3, an average of 30 heats can be used until the dam refractory is completely disassembled.

  In addition, the repair of the dam refractory according to the present invention can be carried out with a small amount of the unstructured refractory applied as much as 20% of the total construction of the dam refractory, and the moisture drying time of the refractory is as shown in FIG. In addition, it can be reduced to ½ compared with the prior art.

DESCRIPTION OF SYMBOLS 1 Induction heating type tundish 2 Receiving hot water side 3 Casting side 5 Coil duct 7 Block refractory 8 Runway refractory 11 Weir refractory 12 Runway refractory 12a Flow path 13-15, 20 Amorphous refractory 16-18 block Refractory 19 Repair block refractory

Claims (2)

A hot water receiving side for receiving molten steel from a ladle, a casting side for discharging molten steel into a mold, and a flow path for passing molten steel from the hot water receiving side to the casting side between the hot water receiving side and the casting side in the width direction The induction heating type tundish provided with the dam refractory provided on the lower sides of the both sides is a method of constructing the dam refractory,
First, a plurality of amorphous refractory layers are constructed by pouring an amorphous refractory around the coil duct for passing the induction heating iron core,
Next, the runner refractory that forms the flow path is placed on the lower side of the weir refractory in the width direction of the enforced amorphous refractory layer, and the block refractory is provided with a plurality of irregular refractory layers. After arranging the runner refractory side and the plurality of irregular refractory layers on the hot water receiving side of the runner refractory and the working surface side of the casting side, the block refractory and the runway brick and the plurality An induction heating type tundish weir refractory construction method, characterized in that an amorphous refractory is constructed in a gap with an amorphous refractory layer. A method of repairing a weir refractory of an induction heating type tundish constructed by the method according to claim 1,
Installed in the gap between the block refractory and multiple amorphous refractory layers from the working side of the hot water receiving side and casting side of the runway refractory by the thickness that can collect the block refractory constructed on the working side. After dismantling the irregular refractory and taking out the block refractory,
The repaired block refractory, which has been repaired from the removed block refractory, is placed on the hot water receiving side of the runway refractory and on the working side of the casting side, and in the gap between the repaired block refractory and a plurality of irregular refractory layers. An induction heating tundish weir refractory repairing method characterized by pouring in an irregular refractory.

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