JPH081311A - Method for working refractory bed of ladle - Google Patents

Abstract

PURPOSE:To reduce the shrinkage rate at the time of drying and to form a sand refractory bed without any cracking by using castable refractory material easily executing working and partial repairing and restraining the working quantity of the castable refractory material in a ladle to low, in the working to a refractory bed in the ladle provided with a nozzle hole and a porous plug hole. CONSTITUTION:A disk-like precast block 9 arranging the preformed round holes 9a, 9b at the positions corresponding to the nozzle hole 6 and the porous plug hole 7 is set to the inner bottom of the ladle 1 and also, the castable refractory material 11 is filled up in the outer periphery. On the other hand, dummies ND, PD having the shapes corresponding to the nozzle hole 6 and the porous plug hole 7 are arranged in the round holes 6, 7. The highly fire- resisive castable refractory material 10 is filled up in the round holes 6, 7 around these dummies ND, PD to form the refractory bed 8. In this way, the working time in the ladle can be shortened and the partial repair of the eroded nozzle part can be executed and production quantity of the waste refractory accompanied with the repairing can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a refractory lining of a ladle used for casting molten metal.

[0002]

2. Description of the Related Art Conventionally, MgO-C bricks have been used as refractory materials for lining ladle walls and floors used to cast molten metal.
Al ₂ O ₃ -MgO-C bricks are mainly used, and the construction of brick bricks has been done by skilled workers with special skills, but there is a problem that the construction requires a relatively large number of man-hours. There is also a concern that in the near future, manpower will become insufficient due to the aging of skilled workers and the difficulty of successors. Also, in a fireproof floor made of bricks, cracks are likely to occur in the joints of the bricks due to repeated hot water reception, and when meltdown of the nozzle progresses, only the mass brick in the nozzle and the refractory bricks around it should be repaired. Replacing the above, loosening occurs between the refractory bricks in other parts, and cracks in joints develop, so in general, all the refractory bricks in the fireproof floor should be rebuilt along with the replacement of the melted nozzle. However, it is becoming difficult to secure a disposal site for the used bricks.

Therefore, attention has been paid to the use of irregular-shaped refractory materials and cast-in refractory materials that are easy to construct and repair. Currently, for the peripheral walls, metal frames are placed in these ladles and kneaded locally. A construction method in which a casting material such as an alumina-spinel material is poured and then filled with a rod-shaped vibrator or the like has already been implemented, whereby shortening of construction time and labor saving are being attempted.

[0004]

From the same point of view, the pouring method as described below has been attempted from the same viewpoint as in the fireproof floor of the ladle. During the drying after pouring from above, it is difficult for the water mixed in the cast refractory material to escape, and due to the difference in shrinkage during drying and during use, cracks occur in the constructed fireproof floor, and a product that can withstand practical use is still available. The reality is not.

[0005] That is, in the conventional construction example of pouring a fireproof floor of a ladle, it is an explanatory view (a) of Fig. 4
As shown in the figure, perm bricks (32) and semi-permanent bricks (33) are constructed on the peripheral wall and bottom of the steel skin (31), and wear refractory material (34) is bricked or poured on the peripheral wall. After the construction by the method, place the mass brick (36) used in the conventional brick building construction in the nozzle (30a) part of the ladle (30), and place it between this mass brick (36) and the surrounding wall. The refractory floor (35) is formed on the inner bottom of the ladle (30) by pouring the pouring refractory material (37) kneaded at the site into the flat surface and drying it. However, in such a fireproof bed (35), since it is poured into a relatively large area for construction, the shrinkage amount during drying is large, and due to the stress generated during the shrinkage, the fireproof bed (35) formed integrally is formed. Easy to crack. Furthermore, since the mass brick (35) to be placed in the nozzle part is generally a precast block or press-molded product whose outer shape is a rectangular parallelepiped, as shown in FIG. Floor
A large crack (C) is easily formed in the (33) because a stress concentration portion is formed. Therefore, when receiving hot water, the molten metal penetrates into the back surface of the fireproof floor (35) through these cracks, passes through the gap with the semi-permanent brick (33), or directly from the cracks in the corners of the nozzle mass brick (36). There was a concern that it would flow to the outer peripheral portion and leak through the outer peripheral portion, and it was not possible to obtain one that could sufficiently withstand practical use.

The present invention has been made in view of the above problems of the prior art.
The amount of cast refractory material in the ladle can be kept low by using the cast refractory material that is easy to install and repair, thus reducing the amount of shrinkage during drying to ensure sound fire resistance without cracks. In addition to being able to form a floor, the construction time and man-hours can be shortened to improve construction efficiency.Furthermore, it is also possible to partially repair the nozzle part that has been melted due to hot water, and the amount of waste refractory generated due to the repair. It is an object of the present invention to provide a method for constructing a fireproof floor of a ladle that can reduce the amount of fire.

[0007]

In order to achieve the above object, the present invention has the following constitution. That is, the method for constructing a ladle refractory bed according to the present invention is a nozzle hole, or when constructing a ladle fire bed with a nozzle hole and a porous plug hole, outside the ladle in advance, pouring refractory material Is cast into a mold and then dried to form a disk shape having an outer diameter slightly smaller than the inner diameter of the inner bottom of the ladle, and at a portion corresponding to the nozzle hole, or the nozzle hole and the porous plug hole. Molding a precast block with a circular mass hole that penetrates with an inner diameter larger than those holes, place this precast block on the inner bottom of the ladle, and pour it into the gap between the outer periphery and the inner peripheral wall of the ladle for fire resistance. While filling and fixing the material, a dummy with a cross-sectional shape corresponding to the cross-sectional shape of the nozzle hole and the porous plug hole is arranged in the circular mass hole, and high fire resistance is provided in the circular mass hole around the dummy. Filling the casting refractory material and forming a refractory bedding.

[0008]

In the construction method of the present invention, the disk-shaped precast block made of cast refractory material formed outside the ladle in advance is placed on the inner bottom of the ladle, and the dummy is placed in the circular mass hole provided in the precast block. Place it in the gap between the outer circumference of the precast block and the inner wall of the ladle, and fix it by filling it with a refractory material, while filling the circular mass holes around the dummy with a pouring refractory material of high fire resistance. Since the fireproof bed is formed on the inner bottom of the ladle, the pouring amount of the pouring refractory material in the ladle can be kept low, the shrinkage amount at the time of drying can be reduced, and the construction time and man-hours can be shortened. In addition, the dummy placed in the circular mass hole of the precast block at the time of construction has a cross-sectional shape corresponding to the cross-sectional shape of the nozzle hole and the porous plug hole, so that the pouring refractory material filled around it is hardened. By extracting, a nozzle hole and a porous plug hole having a predetermined cross-sectional shape can be formed in the inner bottom of the ladle, the inner peripheral wall of which is made of a highly refractory cast refractory material. On the other hand, the precast block does not directly pour into the inner bottom of the ladle, which is difficult to drain water due to its structure, unlike the conventional method of constructing fireproof floors. Since it is molded by casting it in a mold and then drying it,
The molding and drying can be performed under optimum conditions, for example, in a specialized brick factory, and thus a sound and stable product without cracks can be easily obtained. Furthermore, since the casting refractory material of the same kind as the casting refractory material of the precast block and having a high affinity is filled in the outer circumference and the circular mass hole of the precast block, the circular mass hole also has a corner portion. Since there is no crack, it is possible to prevent cracks from occurring between them when the pouring refractory material constructed in the ladle is dried, and the combined effect of these is to provide a stable fireproof floor without cracks on the bottom of the ladle. It can be formed efficiently.

Furthermore, in the fireproof laying of the ladle thus constructed, when the melting damage around the nozzle part progresses due to repeated hot water reception, the surface of the refractory material around the melted nozzle part is chipped and cleaned. However, since the precast block that forms the main part of the nozzle is integrally molded, there is no loosening or cracking in other parts as in the case of conventional brick-laying fireproof floors. While properly chipping around the surrounding refractory material, by arranging the dummy in its nozzle hole, by filling the pouring refractory material of the same material or similar material as the pouring refractory material at the time of initial construction around the dummy, It is possible to partially repair and continue to receive hot water without reconstructing the entire fireproof floor, and thereby to reduce the amount of waste refractory generated due to repair.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fireproof floor construction method according to the present invention will be described below with reference to the drawings. [FIG. 1] is an explanatory view of a construction method for a fireproof flooring according to an embodiment of the present invention, wherein (a) is a sectional view for explaining the construction method, and (b) is a sectional view for the main part of (a). ,
(b) is a perspective view showing the shape of the precast block for fireproof flooring, and (d) and (e) are perspective views showing the outline shape of the dummy used during construction.

In this embodiment, as shown in FIG. 1 (a), the perm bricks (3) and the semi-perm bricks (3) and the semi-permanent bricks () on the peripheral wall and the inner bottom of the iron skin (2) of the ladle (1) 4) is constructed, and after the wear refractory material (5) is poured into the inner peripheral wall or is constructed by brick building, the following is described on the semi-permanent brick (4) on the inner bottom of the ladle (1). In accordance with the procedure, a fireproof floor (8) having a nozzle hole (6) for mounting a pouring nozzle such as a slide nozzle and a porous plug hole (7) for mounting a gas supply porous plug is constructed.

First, prior to the construction, in a brick factory or the like outside the ladle (1), the cast refractory material is kneaded and poured into a pre-prepared open-top mold, and at the same time, a rod-shaped vibrator or vibration is applied. After filling by molding, uniformly casting into a predetermined shape and curing, and then removing from the mold and drying, a precast block with a disk-shaped outer shape as shown in (c) figure (9) To manufacture. Here, the cast refractory material is Al ₂ O ₃ : 70-80 wt%, Al ₂ O ₃ -MgO: 15-
25 wt%, MgO: 0 to 5 wt% as the main component, and 1 to 10 wt% of stainless steel fiber and 0.5 to 10 wt% of this with external binder.
It is a typical alumina-spinel compound containing ~ 3 wt%. Also, this precast block (9)
Is a slightly smaller outer diameter than the inner diameter of the inner bottom of the ladle (1),
In addition, circular mass holes (9a), (9b) are formed in the parts corresponding to the nozzle hole (6) and the porous plug hole (7) with an inner diameter larger than those holes (6) and (7). It is also said that

On the other hand, on the other hand, as shown in FIG.
A drum-shaped nozzle dummy (ND) formed in a cross-sectional shape corresponding to the cross-sectional shape of the nozzle hole (6) of the ladle (1), (e)
As shown in the figure, a frustum-shaped plug dummy (P) with a cross-sectional shape corresponding to the cross-sectional shape of the porous plug hole (7) is formed.
D) and prepare. Here, these dummy (ND) and (PD) are
It is a lightweight material made of wood or hard resin, and has retaining shafts (NDa) and (PDa) protruding from the lower end. Furthermore, the nozzle dummy (ND) is screw-joined or fit-joined at the central small-diameter portion so that it can be separated in the vertical direction.

And the ladle (1) is a semi-permanent brick on the inner bottom.
While cleaning the surface of (4), spread a mixture of MgO mortar or MgO mill powder kneaded with a few% of water on the surface to make it smooth, and then on top of it, precast block (9) above. Bring in with a crane, etc., and arrange with the lower surface in close contact. At this time, the two circular mass holes (9a), (9b) of the precast block (9) are located at the holes for the nozzle and the porous plug already provided on the inner bottom of the ladle (1). To match.

Next, as shown in FIG. 2B, the nozzle dummy (ND) is placed in one circular mass hole (9a) of the precast block (9) and the other circular mass hole (9b) is formed. Within
The plug dummies (PD) are arranged concentrically, and the holding shafts (NDa) and (PDa) at the lower end are held and fixed by a holder (not shown).

In parallel with this, Al ₂ O ₃ : 90 to 95 wt%,
Cr ₂ O ₃ : 2-10 wt%, FC: 2-5 wt% as a main component, and a binder, etc. are externally added and compounded by 3-10 wt% Alumina-chromium high refractory cast refractory material (10) and the cast refractory material of the precast block (9) and the cast refractory material (11) of the same material are kneaded at the site. Then, first, the latter poured refractory material (11) is poured into the gap between the outer circumference of the precast block (9) and the inner peripheral wall of the ladle (1), and this is evenly filled with a rod-shaped vibrator etc. While fixing the block (9) to the inner bottom of the ladle (1), the former high refractory pouring refractory material (10)
(b) As shown in the figure, while pouring them around the nozzle dummies (ND) and plug dummies (PD) in the two circular mass holes (9a) and (9b) of the precast block (9), these are also rod-shaped. Fill uniformly with a vibrator. Further, after the casting refractory materials (10) and (11) are hardened, the nozzle dummy (ND) is removed in the upper and lower two directions and the plug dummy (PD) is removed in the lower direction.

Next, a cast refractory material filled in the circular mass holes (9a) and (9b) of the precast block (9) and in the outer peripheral portion.
(10) and (11) are dried in the same manner as in the conventional method, so that the precast block (9) and the
The fireproof floor (6) and the porous plug hole (7), which are integrated with the pouring refractory materials (10) and (11) filled in the ladle (1) and have a predetermined cross-sectional shape, are provided. 8) Complete the formation of. In this ladle (1), a pouring nozzle such as a slide nozzle is installed in the nozzle hole (6), and a porous plug having air permeability is installed in the porous plug hole (7). Perform hot water and casting.

As described above, in the present embodiment of constructing a fire-resistant floor, most of the fire-resistant floor is made up of precast blocks produced outside the ladle in advance, so that the amount of the cast refractory material to be constructed in the ladle can be reduced. It can be kept low and the amount of shrinkage during drying can be reduced, and compared to conventional brick-laying methods,
The construction time and man-hours inside the ladle can be greatly reduced. Also, precast blocks are not directly poured into the inner bottom of the ladle as in the conventional pouring method for fireproof floors, but are pre-manufactured in a brick factory outside the ladle, so the amount of water added is low. In addition to being able to knead and mold, it is possible to perform heating and drying with a sufficient amount of time, thereby increasing the compressive strength and reducing the apparent porosity, and ensuring its soundness. it can. Further, the outer periphery and the circular mass hole of the precast block are filled with a pouring refractory material having the same material and the same main component as the precast block and having high affinity, and the outer periphery of the circular mass hole has a corner portion. Since it does not exist, it is possible to prevent cracks from occurring at the time of drying the cast refractory material constructed in the ladle, and to ensure the adhesiveness between them. It is possible to efficiently form a stable fireproof floor without cracks on the inner bottom of the ladle.

Furthermore, in the fireproof floor constructed in this manner, if melting damage around the nozzle portion progresses due to repeated hot water reception, even if the surface of the fireproof material around the melted nozzle portion is chipped, Since the precast block that forms the main part is integrally and soundly molded, there is no loosening or cracking in other parts unlike the case of conventional brick-laying fireproof floors. Can be partially repaired without rewinding, and the hot water can be continued, and the amount of waste refractory generated due to the repair can be kept low. This will be described below with a specific example.

The ladle (1) for 20 tons VHF (Vacuum Hold Furnace), which was constructed with the fireproof floor (8) by the procedure of the above-mentioned embodiment,
After repeated ~ 50 charge molten steel hot water, its fireproof floor
The precast block (9) in (8) was not dismantled, and the burnt out nozzle area was partially repaired by the following procedure.

First, the slag metal attached to the work surface of the fireproof floor (8) is removed, and at the same time, the fireproof material around the burnt-out nozzle, that is, the circular mass hole (9a) of the precast block (9). Around the pouring refractory material (10) and the circular mass hole (9a) filled and hardened to form the nozzle hole (6),
As shown in (a) of FIG. 2 which is an explanatory sectional view of the repair procedure, the chip was cleaned and the slide nozzle (not shown) attached to the nozzle hole (6) was removed.
At this time, in this example, the pouring refractory material (10) filled and hardened in the circular mass hole (9a) was chipped off at least a thickness range of about 100 mm from its working surface to remove the heat received by the hot water. The property-deteriorated part due to was surely removed, thereby ensuring the adhesiveness with the cast refractory material (10) to be refilled during the subsequent repair.

Next, as shown in FIG. 2B, the nozzle dummy (ND) used at the initial construction is similarly arranged in the chip cleaning portion, that is, the circular mass hole (9a), in the same core. Fixed,
Subsequently, a high refractory pouring refractory material (10) of the same material as that at the time of initial construction was poured around the nozzle dummy (ND), and similarly filled uniformly with a rod-shaped vibrator or the like. At this time, the part of the precast block (9) that has been chipped and cleaned around the circular mass hole (9a) may be filled with pouring refractory material of the same material as this precast block (9). Before filling around the nozzle dummy (ND), place a dummy cylinder with the same diameter as the circular mass hole (9a) in the circular mass hole (9a), and fill the same area with a pouring refractory material. -After hardening and removing the dummy cylinder, filling around the nozzle dummy (ND) may be performed. Then, after the cast refractory material (10) is cured,
The nozzle dummy (ND) was removed vertically in two directions, and the cast refractory material (10) was dried to complete the partial repair of the fireproof floor (8) of the ladle (1). And the ladle concerned (1)
A new slide nozzle was attached to the repaired nozzle hole (6) in No. 1, and the hot water reception and casting were continued.

In this example, with this ladle, 45 to
After repeatedly receiving hot water for 50 charges, the burned out nozzle area was partially repaired by the same procedure as above. Then, the cycle of hot water reception and repair was repeated to continue the hot water reception and casting, and when it reached the fourth time, this fireproof bed was dismantled and re-installed in the same procedure as the above-mentioned initial installation. In addition, we confirmed the state of the fireproof floor after each repair, but there was no cracking in the precast block, which was the main component of the block, although there was a progress of reduction in thickness corresponding to the number of hot water charges, and the repair was also performed. At times, the adhesiveness with the filled pouring refractory material was good, and no intrusion of the molten metal from the joint was observed. Therefore, before dismantling and reconstructing this fireproof floor,
We were able to stably repeat the hot water of 200 charges.

On the other hand, the conventional ladle, which has the same purpose and capacity as the ladle of this example and whose fireproof floor is made of bricks of Al ₂ O ₃ -MgO-C quality, uses 45 to 50 charges. Then, the molten metal begins to enter through the joints of the bricks and into the gap between the bricks of the fireproof floor and the semi-permanent bricks. It was rebuilding all of the bricks. Therefore, as compared with the conventional ladle whose refractory floor is constructed of bricks, the amount of waste refractory generated can be significantly reduced in the ladle of this example, as shown in comparison with [Table 1]. As shown in the graph of [Fig. 3], the basic unit index of the refractory used can also be greatly improved. In addition, [FIG. 3] is a graph showing the unit consumption index of the refractory used in the fireproof floor of this example in comparison with the unit consumption index of the conventional brick-laid fireproof floor. The curve A shows the values of this example, and the solid curve B shows the values of the conventional one.

[0025]

[Table 1]

In the above-mentioned embodiments, a ladle having a form capable of receiving and casting molten steel, having a porous plug, and blowing gas for degassing, decarburizing or bubbling. However, the method of the present invention is not limited to this, and can be applied to, for example, those not provided with a porous plug. Further, it receives and casts molten metal other than steel. It can be applied to the fireproof floor of the ladle to obtain the same excellent effect.
Further, as the type of the cast refractory material used in that case, a material corresponding to the characteristics of the molten metal to be received may be selected. Further, in the repair example of the fireproof bed of the above-mentioned embodiment, only the repair procedure of the nozzle portion was described, but as in the same example, when the porous plug portion is melted and damaged, the nozzle portion is Needless to say, partial repair can be performed by the same procedure.

[0027]

As described above, according to the method for constructing the fireproof floor according to the present invention, the amount of the cast refractory material in the ladle is used by using the cast refractory material which can be easily constructed and partially repaired. Therefore, the amount of shrinkage during drying can be reduced to form a sound fireproof floor without cracks, and the construction time and man-hours can be shortened to improve construction efficiency. It is also possible to partially repair the nozzle portion that has been melted by the hot water, and it is possible to obtain a great effect that the amount of waste refractory generated due to the repair can be significantly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view of a construction method for a fireproof flooring according to an embodiment of the present invention, in which (a) is an explanatory sectional view of the construction method, and (b) is (a).
FIG. 2 is a perspective view showing a shape of a precast block for a fireproof floor, and (d) and (e) are perspective views showing a schematic shape of a dummy used during construction.

FIG. 2 is an explanatory cross-sectional view of a procedure for repairing the nozzle portion related to the fireproof bed of the embodiment of the present invention.

FIG. 3 is a graph showing the unit consumption index of the refractory used for the fireproof flooring of the example of the present invention in comparison with the unit consumption index of the conventional brick-laid fireproof flooring.

FIG. 4 is an explanatory diagram of a conventional pouring construction example of a fireproof floor.

[Explanation of symbols]

(1) --- Ladle, (2) --- Steel skin, (3) --- Permanent brick, (4) --- Semi-permanent brick, (5) --- Wear refractory material, (6) --- Hole for nozzle,
(7) --- Porous plug hole, (8) --- Fireproof floor, (9) --- Precast block, (9a), (9b) --- Circular mass hole (10) --- Pouring refractory material , (11) --- Cast refractory, (ND) --- Nozzle dummy, (PD) --- Plug dummy.

Front page continuation (72) Inventor Ryoya Ikoma 2-3-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Kobe Steel Works Takasago Plant (72) Inventor Masaaki Kobayashi 2-3-1, Niihama, Arai-cho, Takasago, Hyogo Prefecture Kobe Steel, Ltd. Takasago Works (72) Inventor Yutaka Okada 2-3-1, Niihama, Arai-machi, Takasago-shi, Hyogo Prefecture Kobe Steel Works Takasago Works, (72) Inventor Masuda 2-chome, Niihama, Arai-cho, Takasago-shi, Hyogo Prefecture No. 3-1 Takasago Works, Kobe Steel, Ltd. (72) Inventor Atsushi Tomioka 2-3-3, Niihama, Arai-cho, Takasago-shi, Hyogo Prefecture (72) Takasago Works, Kobe Steel, Ltd. (72) Toshiro Konobu Bizen, Okayama Prefecture 7904 Honami Ichi, Koa Refractory Industry Co., Ltd. (72) Inventor Takayuki Ueoka 7904 3 Honami Honami, Okayama Prefecture Koa Fire Refractory Industry Co., Ltd.

Claims (1)

[Claims] 1. When constructing a refractory laying of a ladle having nozzle holes, or nozzle holes and porous plug holes, the cast refractory material is cast outside the ladle in advance and then dried. , A disk shape having an outer diameter slightly smaller than the inner diameter of the inner bottom of the ladle, and at the portion corresponding to the nozzle hole, or the nozzle hole and the porous plug hole,
Mold a precast block with a circular mass hole that penetrates with an inner diameter larger than those holes, place this precast block on the inner bottom of the ladle, and pour it into the gap between the outer periphery and the inner peripheral wall of the ladle to make a refractory material. While filling and fixing, the dummy with the cross-sectional shape corresponding to the cross-sectional shape of the nozzle hole and the porous plug hole is arranged in the circular mass hole, and the high fire resistance pouring fire resistance is provided in the circular mass hole around the dummy. A method for constructing a fireproof floor of a ladle, which comprises filling the material with a fireproof floor.