JP2000046477A - Ladle furnace bottom laying structure and method for executing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve usability by dividing a furnace bottom of a ladle into a molten metal contact part and a general bed, laying a precast block and providing a molten metal guiding groove having a down slope toward a molten metal discharging port installing part at the bed, thereby enhancing an efficiency of a furnace building work. SOLUTION: A furnace bottom is divided into a general bed 2 and a molten metal contact part 3, a molten metal discharging port 4 is provided at the bed 2, and a molten metal guiding groove 5 having a down slope toward the port 4 is provided. The bed 2 is divided, and divided into three blocks including the part 3, and the groove 5 is connected to continue between the blocks. The groove 5 can be provided toward the port 4 by sandwiching the groove 5 between both sides of a porous plug 6. A bottom of the bed 2 provided with the groove 5 is provided with a down slope to flow molten metal toward the port 4. As a precast block structure, the method for executing is facilitated, thereby reducing local melt loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory floor structure at the bottom of a ladle used for iron making and steel making, and a method for constructing the furnace.

[0002]

2. Description of the Related Art In recent years, as a method of constructing a ladle bottom, for the purpose of labor saving, pouring from a brick floor with an amorphous refractory has been mainly performed. However, in the case of this casting, there are problems such as the necessity of large-scale equipment such as a kneader and a drier, a long curing and drying time, and the formation of dust during kneading.

Further, as an example of not only using a casting material but also partially using a precast block, for example, Japanese Patent Application Laid-Open No. Hei 6-71422 discloses that a hot water contact portion is formed using a precast block, and the others are castable. The construction is described, and Japanese Utility Model Application Laid-Open No. 7-6693 discloses that the hot water contact part is constructed by a precast block, the tuyere side is brick, and the other part is constructed by a casting material. ing.

However, also in the above-mentioned example, since the bottom of the ladle uses not only the precast block but also the casting material, the problem caused by the casting is not solved. Rather, due to the combination of the pouring method, the casting surface of the pouring part forms a horizontal smooth surface, and a lot of residual metal remains on the bottom of the ladle when the molten metal is discharged, leading to not only a decrease in yield but also local melting. It will be easier.

[0005] Japanese Patent Application Laid-Open No. 57-187163 discloses that a precast block is applied to a work lining, which is a work lining at the bottom of a ladle, to save labor. In this case, the lifting jig is preliminarily embedded in the precast block, and it is handled using the lifting jig for the drying step during the production of the precast block, and for the subsequent actual furnace setting. It has become. Therefore, the embedded lifting jig is melted when the actual furnace is used, so that the molten metal can be easily inserted into the precast block, and the structure of the lifting jig embedded portion is significantly weakened when the actual furnace is used. Further, there is a drawback that an internal crack occurs in the block due to a difference in thermal expansion between the precast block and the lifting jig, resulting in a significant decrease in service life.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to improve the efficiency of the furnace-building work when laying a precast block at the bottom of a ladle, to eliminate local melting of the laid ladle bottom, and to improve its durability. Is to improve.

[0007]

According to the present invention, a precast block is laid by dividing a furnace bottom portion of a ladle into at least a hot water contact portion and other general laying portions. And a molten metal guiding groove having a downward slope is provided.

[0008] The general floor portion may be divided into one to two to four parts depending on the size of the construction body. In addition, the divided hot water contact portion and the general laying portion can be laid in a state where they are integrally assembled with mortar or the like in advance.

In applying the precast block to the furnace bottom of a large ladle of more than 1 ton, it is necessary to divide the casting frame into at least a hot water contact portion and a general floor portion other than that, thereby avoiding an increase in the size of the casting frame. At the same time, it is possible to avoid difficulties in handling and drying operations, and to prevent an increase in manufacturing costs.

[0010] The general floor portion is provided with a molten metal guiding groove having a downward slope toward the molten metal outlet setting portion. This is to prevent the molten metal from remaining easily as a pool when the construction thickness of the general laying part is constant and the molten metal is left in a horizontal shape, thereby preventing local melting by the molten metal. Therefore, the molten metal guiding groove is sufficiently effective if it has a downwardly inclined groove shape so as to flow toward the molten metal pouring outlet. The downward slope is preferably 5 degrees or more with respect to the horizontal plane, and more preferably about 10 to 20 degrees.

In addition, a ladle bottom structure in which the surface of the general floor is provided with a downward inclination of about 5 to 10 degrees toward the molten metal spout installation portion or the molten metal guiding groove so that the molten metal flows toward the molten metal outlet. By doing so, the hot water pool can be eliminated and the local erosion can be eliminated.

The work of laying a precast block manufactured by dividing the furnace bottom of the ladle into at least a hot water contact part and a general laying part is performed by opening a handling slit on the operating surface side of the general laying part, After hanging the jig for hanging, lay the jig for pulling out, fill back the slit with irregular shaped refractory, and fill the gap between the general laying part, hot water contact area and side wall with irregular shaped refractory. . This makes it possible to provide a ladle furnace bottom structure in which the fragile portion of the precast block is not formed.

The slit serving as a hooking portion has its opening slightly larger than the shape of the insertion part of the lifting jig, and the internal shape of the insertion is determined in consideration of the weight of the block and the construction thickness. And a hanging space in which the hanging member rotates and can be hooked. This slit can be melted or burned off at the corresponding location during the casting process. Wax, paraffin wax, styrofoam, wood, paper, etc., or a plastic bag filled with sand, water, etc. Embed the molded body that fits,
It is formed by removing or burning away during the drying step, or by removing the mold after hardening the general floor block.

Further, if there is a joint between the precast blocks, the hot water contact portion is disadvantageous in terms of durability when used in an actual furnace.
For this reason, it is desirable that the hot water contact portion where the actual furnace wear is severe is made into an integrated one having a thicker construction thickness than the general floor portion.

[0015] The refractory used for backfilling or filling is desirably the same material as the precast block or a highly durable castable refractory. Further, a flow value as a fluidity indicating the filling property was measured according to JIS R2512. If this value is 150 mm or more, it indicates that the compounded state has a considerably good filling property, but it is more preferably 200 mm or more.

The precast block has a refractory structure in advance, and can be laid in a dry state, so that it can be transported by a large lift and set on the bottom of the ladle furnace so that the actual furnace can be used immediately on site, and a large construction period can be achieved. Since shortening and labor saving can be achieved, it is possible to cope even under a tight process when using an actual furnace.

Thus, even when a precast block having a large shape is used, the handling of the block is facilitated by using a crane or a lift during the furnace-building operation, and not only the efficiency and labor-saving of the furnace are made possible, but also The durability can be improved as compared with the construction of only pouring.

When laying the precast block at the bottom of the ladle furnace, an irregular refractory such as mortar is filled into the surface on the steel shell side, the side wall, and the gap between each block. In this case, if the amount of the amorphous filler used or the amount of added water is large, a drying step is required after setting the precast block. Therefore,
It is desirable that these amorphous fillers have as little added water as possible, and it is desirable to use semi-wet or dry products rather than wet materials. Use the one with less.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION As a refractory aggregate of a precast block used in the present invention, siliceous materials such as silica, silica sand, fused silica, hydrated amorphous silica and anhydrous amorphous silica as oxide materials, mullite and bauxite are used. , Van earth shale,
Alumina such as sillimanite, kyanite, sintered alumina, electrofused alumina, calcined alumina, and silica such as raw stone, chamotte, pottery stone, clay, kaolin and bentonite
Zirconia such as alumina, zircon, and zirconia;
Electrofused magnesia, seawater magnesia or synthetic magnesia, natural magnesia, alumina-magnesia spinel,
Basic properties such as calcium oxide, spinel, chromium oxide,
Chromium such as chromite can be used. Silicon carbide, aluminum carbide, zirconium carbide and the like can be used as the carbide raw material. As the nitride raw material, zirconium nitride, silicon nitride, silicon iron nitride, boron nitride, aluminum nitride and the like can be used. As a raw material containing carbon, carbonaceous raw materials such as natural graphite such as coke, flaky graphite, flaky graphite and earthy graphite, artificial graphite, calcined anthracite, coal powder, pitch powder, carbon brick and electrode waste can be blended. In addition to the above, one selected from the group consisting of all refractory materials such as borides such as boron carbide and silicides such as silicon and ferrosilicon can be used alone or in combination of two or more as needed.

In the precast block of the present invention, various metal fibers and other fibers such as carbon fiber and SiC fiber may be used in combination, if necessary. In addition, an antioxidant such as glass, metal powder or metal particles may be added.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a ladle bottom structure according to the present invention;

FIG. 1 shows an example of a bottom structure of a ladle 1 which is divided and laid, as viewed from above. FIG. 2A shows an example in which the general floor portion 2 and the hot water contact portion 3 are divided into two parts. The general floor portion 2 is provided with a molten metal outlet 4 and has a downward inclination toward the outlet 4. It has a molten metal guiding groove 5. Reference numeral 6 denotes a porous plug hole.

FIG. 2 (b) shows an example in which the general floor portion 2 is divided into two and divided into three blocks including the hot water contact portion 3, and the molten metal guiding groove 5 is continuous between the blocks. Is joined to. As a result, when the actual furnace is used, FIGS. 7A and 7B have the same functions. The division of this general flooring is 3 or 4 depending on the whole size.
There is no problem in workability and functionality even if the process is performed up to the division. Further, the molten metal guiding groove 5 does not need to be in the position or shape as shown in the figure, and may be provided toward the pouring port 4 so as to sandwich the porous plug 6 from both sides.

FIG. 2 is a cross-sectional view taken along the line II of FIG. 1 (a). It is provided.

FIG. 3 is a sectional view taken along the line II-II of FIG. 1 (a), and shows a structure in which the hot water contact portion 3 is made thicker than the general laying portion 2 and laid.

FIG. 4 shows a modification of FIG. 2 in which the surface of the general floor portion 2 is also provided with an inclined portion 8 toward the molten metal guiding groove 5 or the spout 4 so as to flow from both sides so that the pool is further filled. Formation can be prevented.

FIG. 5 is a perspective view showing an example of a general-split-part divided body of a precast block. General floor block 12
Is provided with a molten metal guiding groove 15 toward the molten metal pouring hole 14, so that the molten metal can be discharged from the pouring nozzle to be fitted, and the pool can be eliminated. Reference numeral 16 denotes a hole for a porous plug, and 17 denotes a slit 17 for suspension according to the present invention.
Is shown.

FIG. 6 is a view for explaining the slits 17 formed in the general laying block 12 used in the furnace construction of the ladle bottom structure. The same figure (a) shows the general floor block 1
In the partial plan view of FIG. 2, the slit 17 is slightly larger in width a and width b so as to allow enough space for the lifting jig to be inserted. FIG. 2B is a sectional view taken along the line III-I of FIG.
It is a figure which shows II sectional drawing. The depth c of the slit 17 shown in FIG.
In consideration of the strength at the time of lifting, it is necessary not to be too thin, and it is necessary to take into account the thickness d of the lifting jig in the engaging space 18 and the width b of the shaft portion. Further, the engaging portion space 18 is formed so that the engaging portion of the lifting jig can be rotated. This hook space 18
Was obtained by disposing styrofoam in the form of the entire slit when casting the general floor block 12, and removing the die after the general floor block 12 was cured. In addition, about the installation state of the slit type,
Although it is possible to embed it in the block,
Considering the burying work at the time of casting and the removing work after hardening, the bottoming method as shown is simple.

FIG. 7 shows an embodiment of the furnace for building the blocks shown in the above figures. FIG. 5A is a diagram showing a state in which the general laying block 12 is suspended, and FIG. 5B is a diagram showing a lifting jig 19 used when lifting the general laying block 12 in FIG. It is an enlarged view. In these figures, the lifting jig 19 inserted into the slit 17 of the general laying block 12 is rotated in the engaging portion space 18 shown in FIG. The shaft 21 has a length which comes out of the shaft c and has a ring shape, T
, Hook-shaped hanging member 24, etc.
The second wire 23 has a structure capable of being hung by a hanging member 25 attached to the tip of the wire 23.

The lifting method of the block is as follows. The lifting jig 19 is inserted into the slit 17 of the block 12,
After lowering to a depth of (c + d), the lifting jig is rotated about 1/4 turn, so that the lifting jig is lifted, so that the block can be lifted. FIG.
By inserting the lifting jigs 19 into the three slits 17 in (a), the general laying block 12 can be lifted using the lifting equipment 22 using a crane or the like (not shown). After the block 12 is set at a predetermined position in this manner, the lifting jig 19 is pulled out from the slit 17 and the slit 17 is filled with an irregular refractory.

In the conventional method in which the lifting jig embedded in the precast block cannot be completely removed after setting the precast block, the difference in thermal expansion between the precast block and the lifting jig during use of the actual furnace causes Internal cracks were generated in the block, resulting in a significant reduction in service life. On the other hand, according to the construction method of installing the precast block of the present invention, since the construction can be carried out without leaving the lifting jig in the furnace bed, there is no wear due to the intrusion of the molten metal and the durability is improved.

[0032]

According to the present invention, the following effects can be obtained.

(1) By adopting a divided structure of the precast block, not only the construction method is easy, but also there is no dust and there is no compounding loss during construction, so that the working environment is good.

(2) By providing the molten metal guiding groove having a downward slope toward the molten metal outlet of the general floor, the local melting loss is reduced and the durability of the ladle furnace floor is extended. Also, by providing a gentle downward slope toward the molten metal outlet or the molten metal guiding groove on the bottom of the furnace, the effect of reducing local erosion and extending the durability of the ladle furnace bed was obtained.

(3) Since the precast block is simply lifted and set with a crane or the like, the construction efficiency and the construction period at the construction site can be greatly reduced.

(4) Since a precast block is used, it is possible to select a material having a fire resistance, corrosion resistance, spalling resistance and other characteristics and a work thickness in accordance with the actual furnace use conditions regardless of the work conditions. Thereby, the service life of the refractory is prolonged.

(5) Since the lifting jig can be constructed without remaining in the precast block, there is no wear due to intrusion of the molten metal, and there is no crack due to a difference in thermal expansion between the lifting jig and the durability.

[Brief description of the drawings]

FIG. 1 shows an example of a bottom structure of a ladle that is divided and laid, as viewed from above. (A) shows an example in which the general floor portion and the hot water contact portion are divided into two parts, and (B) shows an example in which the general floor portion is divided into two and a block including the hot water contact portion is provided.

FIG. 2 is a sectional view taken along line II of FIG.

FIG. 3 is a sectional view taken along line II-II of FIG.

FIG. 4 shows a modification of FIG.

FIG. 5 shows an example of a general-split section of a precast block.

FIG. 6 is a view for explaining a slit formed in a general floor block used in the furnace construction of the ladle bottom structure.

FIG. 7 shows a form of a furnace using a block.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Ladle 2 General bedding part 3 Hot water contact part 4 Melt pouring port 5 Melt guiding groove 6 Porous plug hole 7 Downslope 8 Inclined part 12 General laying block 14 Melt pouring hole 15 Melt guiding groove 16 Porous plug hole 1
7 Slit 18 Engagement space 19 Lifting jig
Reference Signs List 20 hook part 21 shaft member 22 lifting equipment 2
3 Wire 24 Hanging member 25 Hanging member

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Nobuyasu Kawamoto 1-3-16 Nakadori, Kure-shi, Hiroshima Kurosaki Ceramics Co., Ltd. The 1st Division Sales Department Hiroshima Sales Office (72) Inventor Naoki Shigematsu New Yamaguchi Prefecture No. 4976, Nomura Minamicho, Nanyo City Nisshin Steel Corporation Shunan Steel Works, Ltd. (72) Inventor Atsushi Yamamoto No. 4976, Nomura Minamimachi, Shinnanyo City, Yamaguchi Prefecture

Claims (3)

[Claims] A precast block is laid by dividing a furnace bottom portion of a ladle into at least a hot water contact portion and other general laying portions, and the general laying portion has a molten metal having a downward inclination toward a molten metal outlet setting portion. Ladle furnace bottom structure with guide grooves. 2. The ladle furnace bottom laying structure according to claim 1, wherein the general laying portion is provided with a downward inclination toward the molten metal outlet setting portion or the molten metal guiding groove. 3. A precast block produced by dividing the ladle bottom into at least a hot water contact portion and a general floor portion,
A lifting jig is hung on a hanging slit opened on the operating surface side of the general laying part, laid on the furnace bottom, the lifting jig is pulled out, and the slit is buried with an indefinite refractory material. A method of constructing a ladle furnace bottom where the gap between the hot water contact area and the side wall is filled with an irregular refractory.