JPH11291025A - Lower nozzle for slide gate and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lower nozzle for slide gate which can prevent the enlargement of crack in the diameter direction of a nozzle body. SOLUTION: In this lower nozzle 1 for slide gate composed of the nozzle body 2 having a large diameter part 2a at the upper end part and a protecting iron shell 3 covering almost the whole outer periphery, the nozzle body 2 is formed of a non-burining refractory and many projections 4 are arranged on the inner peripheral surface of the protecting iron shell so as to separate in the axial direction and the peripheral direction, and each projection 4 is bitten into the outer peripheral part of the nozzle body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower nozzle for a slide gate attached to a casting container such as a ladle or a tundish, and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a lower nozzle for a slide gate is vertically provided on a lower plate of a slide gate to guide a molten metal to a tundish or a mold, and an upper end attached to the lower plate has a large diameter portion. The nozzle body is composed of a fired or unfired refractory material, and a protective steel shell covering almost the entire outer periphery thereof with a mortar. And
The lower nozzle for the slide gate applies mortar to almost the entire outer circumference of the nozzle body made of a fired or non-fired refractory manufactured in advance, and applies the mortar to the entire inner circumferential surface of the protective steel shell and then fits both. Manufactured together.

[0003]

However, in the conventional lower nozzle for a slide gate, it is difficult to prevent the gap (axial interval) of a radial crack generated in the nozzle body during use from increasing. When the mortar is insufficiently filled, there is a problem that a hole is formed in the protective steel shell with the expansion of the crack, and a leak of water frequently occurs. In addition, since the nozzle body and the protective iron skin are manufactured by fitting with a mortar interposed therebetween, a mortar application process and a fitting process of the both are required, which complicates the process and consequently increases the cost. There is. Accordingly, an object of the present invention is to provide a lower nozzle for a slide gate and a method for manufacturing the same, which can prevent a crack in a radial direction of a nozzle body from expanding and can simplify a process.

[0004]

In order to solve the above-mentioned problems, a first lower nozzle for a slide gate according to the present invention comprises a nozzle body having a large-diameter portion at an upper end, and a protective iron cover covering substantially the entire outer periphery thereof. In the lower nozzle for a slide gate consisting of, the nozzle body is formed of unfired refractory,
A large number of protrusions are provided on the inner peripheral surface of the protective steel shell in the axial direction and the circumferential direction, and each protrusion is cut into the outer peripheral portion of the nozzle body. The second lower nozzle for a slide gate is the same as that of the first embodiment, wherein a heat-insulating coat that develops according to the temperature during use is interposed between the outer peripheral surface of the nozzle body and the inner peripheral surface of the protective steel shell. It is characterized by. On the other hand, the first method for manufacturing a lower nozzle for a slide gate is a method for manufacturing a lower nozzle for a slide gate comprising a nozzle body having a large diameter portion at an upper end portion and a protective steel covering substantially the entire outer periphery thereof. A lower mold with a core rod set up was set on a mold frame that could be set with the protective iron shell with the upper end facing up, and a number of protrusions were provided on the inner peripheral surface separated from each other in the axial and circumferential directions. After setting the protective iron shell, the refractory raw material is put into the mold, and thereafter, the upper mold is set on the mold and the refractory raw material is pressed. A second method for manufacturing a lower nozzle for a slide gate includes a method for manufacturing a lower nozzle for a slide gate comprising a nozzle body having a large diameter portion at an upper end portion and a protective steel covering almost the entire outer periphery thereof. After setting a protective steel shell provided on the inner peripheral surface with many protrusions spaced apart in the axial and circumferential directions with the upper end facing down, the castable refractory is poured into the protective steel shell. It is characterized by the following. The third method of manufacturing the lower nozzle for a slide gate is the method according to the first or second method,
The invention is characterized in that a heat insulating coating agent that develops depending on the temperature at the time of use is applied in advance to the inner peripheral surface of the protective iron shell.

As the unfired refractory, in the case of press molding, a refractory material such as alumina-carbon or magnesia-carbon is used, and phenol resin, aluminum phosphate, and sodium silicate are used as a binder. Used to improve the movement of refractory raw materials during molding. For example, in an alumina-carbon refractory raw material, a novolak type phenolic resin is used in an external ratio of 5 to 5%.
10 wt% is added. On the other hand, in the case of cast molding, refractory materials such as alumina, high alumina, and magnesia-spinel are used, and high alumina cement is used as a binder for the refractory materials.

The protrusions on the inner peripheral surface of the protective shell are formed by projecting or beading the protective shell using a punch or the like, welding a disk-shaped member to the protective shell, bending or cutting the protective shell, Alternatively, it is provided by welding an anchor stud to a protective steel shell.

[0007] The heat-insulating coat developed depending on the temperature at the time of use of the lower nozzle is 0.1 to 1.0 mm
It is provided by a foaming coating agent applied with a thickness of. As the foamable coating agent, inorganic materials such as SiO ₂ , M
a raw material containing gO and Al ₂ O ₃ (for example, vermiculite, andalusite, etc.) whose volume expansion coefficient at a temperature of 500 to 1000 ° C. becomes 50 to 500 times;
In organic, expandable graphite is used.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a half sectional front view showing a first embodiment of a lower nozzle for a slide gate according to the present invention. The lower nozzle 1 is formed of an unfired refractory made of a suitable refractory material, and has a large diameter portion 2 at an upper end portion.
The nozzle body 2 has a protective iron shell 3 that covers substantially the entire outer periphery of the nozzle body 2 having the nozzle body 2. A large number of projections 4 are provided on the inner peripheral surface of the protective steel shell 3 at appropriate intervals in the axial direction and the circumferential direction by projecting the protective iron shell 3 using a punch or the like. 2 is cut into the outer periphery.

In the lower nozzle 1 having the above structure, even if a radial crack is generated in the nozzle body 2 during use, the movement of the nozzle body 1 in the axial direction is restrained by the projections 4. The expansion of the gap is prevented. Therefore, unlike the conventional case, a hole is not formed in the protective steel shell, and the molten metal does not leak.

FIG. 2 is a half sectional front view showing a second embodiment of the lower nozzle for a slide gate according to the present invention. The lower nozzle 5 is provided with a heat insulating coat 6 between the outer peripheral surface of the nozzle main body 2 and the inner peripheral surface of the protective steel shell 3 that exhibits heat insulation due to volume expansion depending on the temperature when the lower nozzle 5 is used. Things. The other configuration is the same as that of the first embodiment, so that the same components and the like are denoted by the same reference numerals and description thereof is omitted.

In the lower nozzle 5 having the above-described configuration, in addition to the same operation and effect as those of the first embodiment, the protective iron for the nozzle main body 2 is developed by using the heat insulating coat 6 to exhibit the heat insulating property due to the volume expansion of the heat insulating coat 6 during use. As the binding force of the skin 3 increases,
The heat insulation of the lower nozzle 5 is enhanced. By increasing the heat insulating property, it is possible to prevent the turbulence due to the cooling of the molten metal in the vicinity of the outlet of the lower nozzle, and to prevent the oxidation due to the increase in the surface temperature of the protective steel shell 3.

In each of the embodiments described above, a case has been described in which the projections 4 on the inner peripheral surface of the protective shell 3 are provided by overhanging the protective shell 3. However, the present invention is not limited to this. Instead, for example, like the protective steel shells 7, 8, and 9 shown in FIGS. 3, 4, and 5, a disk-shaped steel member is provided on the inner peripheral surface of the protective steel shell 7 in the axial direction and the circumferential direction. To the projections 11 which are appropriately spaced apart and welded, the projections 11 which are cut or bent or raised inwardly at locations which are appropriately spaced apart in the axial and circumferential directions of the protective skin 8, or A projection 12 or the like may be formed on the inner peripheral surface by welding an anchor stud such as a Y-type or a V-type at an appropriate distance in the axial and circumferential directions.

In order to manufacture the lower nozzle 5 of the second embodiment described above, first, as shown in FIG. 6, a nozzle body is set in a mold 13 in which the protective iron cover 3 can be set with its upper end facing upward. In addition to setting a lower die 15 having a core rod 14 for forming two nozzle holes, a number of protrusions 4 are provided on an inner peripheral surface of the lower nozzle 5 while being spaced apart in the axial and circumferential directions. The protective iron cover 3 was formed on the inner peripheral surface of a heat insulating coat 6 formed by applying a heat insulating coating agent exhibiting heat insulating properties by volume expansion depending on the temperature during use to a thickness of 0.1 to 1.0 mm. Next, as shown in FIG. 7, after the refractory raw material 16 is charged into the mold 13, the upper mold 17 is set on the mold 13 and pressed at a required pressure as shown in FIG. Then, the mold was removed and dried to obtain a lower nozzle 5.

Therefore, in the method of manufacturing the lower nozzle 5 described above, the step of applying mortar to the nozzle body and the protective iron skin, the step of fitting the two, and the step of drying the mortar as in the prior art are omitted.

The production of the lower nozzle 5 is not limited to the method described above. For example, as shown in FIG. 9, a core rod 18 for forming a nozzle hole of the nozzle body 2 is formed.
A large number of projections 4 are provided on the inner peripheral surface of the lower die 19 having the vertical nozzles, which are spaced apart in the axial direction and the circumferential direction. After the protective shell 3 formed on the inner peripheral surface of the heat insulating coat 6 formed by applying the agent with a thickness of 0.1 to 1.0 mm is set with its upper end facing down, the castable refractory is placed in the protective shell 3. 20 and then castable refractory 20
Was solidified and then released from the mold, and dried to obtain a lower nozzle 5.
When the lower nozzle 1 is manufactured, the above-described methods may be used without forming the heat insulating coat 6 on the inner peripheral surface of the protective steel shell 3.

[0016]

As described above, according to the first slide gate lower nozzle of the present invention, even if a radial crack is formed in the nozzle body during use, the nozzle body moves in the axial direction. Are restrained by the respective projections, so that it is possible to prevent the crack from expanding, and thus to prevent the occurrence of leaks. According to the second lower nozzle for the slide gate, in addition to the function and effect of the first one, at the time of use, due to the expression of heat insulating properties due to the volume expansion of the heat insulating coat, the binding force of the protective steel to the nozzle body increases, and Since the heat insulation of the nozzle is enhanced, the generation of cracks and the expansion of the gaps can be further suppressed, and the service life can be prolonged. On the other hand, according to the first and second methods for manufacturing the lower nozzle for the slide gate, the first lower nozzle for the slide gate can be obtained. Since the fitting step and the like can be omitted, the steps can be simplified, and the cost can be reduced. According to the third method of manufacturing the lower nozzle for the slide gate, the second lower nozzle for the slide gate can be obtained in addition to the functions and effects of the first and second methods.

[Brief description of the drawings]

FIG. 1 is a first view of a lower nozzle for a slide gate according to the present invention.
FIG. 3 is a front view of a half section showing the embodiment.

FIG. 2 is a second view of the lower nozzle for the slide gate according to the present invention.
FIG. 3 is a front view of a half section showing the embodiment.

FIG. 3 is a half sectional front view of another protective iron shell in the lower nozzle for the slide gate according to the present invention.

FIG. 4 is a half sectional front view of still another protective iron shell in the lower nozzle for the slide gate according to the present invention.

FIG. 5 is a half sectional front view of still another protective iron shell in the lower nozzle for the slide gate according to the present invention.

FIG. 6 is a cross-sectional view of a first step showing an example of an embodiment of a method for manufacturing a lower nozzle for a slide gate according to the present invention.

FIG. 7 is a sectional view of a second step showing an example of the embodiment of the method for manufacturing the lower nozzle for the slide gate according to the present invention.

FIG. 8 is a sectional view of a third step showing an example of the embodiment of the method for manufacturing the lower nozzle for the slide gate according to the present invention.

FIG. 9 is a sectional view showing another example of the embodiment of the method of manufacturing the lower nozzle for the slide gate according to the present invention.

[Explanation of symbols]

 2 Nozzle body 2a Large diameter part 3 Protective steel 4 Protrusion 6 Thermal insulation coat 7 Protective iron 8 Protective iron 9 Protective iron 10 Protrusion 11 Protrusion 12 Protrusion 13 Formwork 14 Core rod 15 Lower mold 16 Refractory material 17 Upper mold 18 core rod 19 lower mold 20 castable refractory

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takaaki Hirano 1 Minami Fuji, Ogakie-cho, Kariya City, Aichi Prefecture Inside the Toshiba Cell Mix Co., Ltd. (72) Keiko Okada 1 Minami Fuji, Ogakie-cho, Kariya City, Aichi Prefecture Lamix Corporation Kariya Works (72) Inventor: Takigawa Osamu 1 Minamifuji, Ogakie-cho, Kariya-shi, Aichi Prefecture Toshiba Ceramics Corporation Kariya Works

Claims (5)

[Claims] A nozzle body having a large-diameter portion at an upper end portion;
In a lower nozzle for a slide gate composed of a protective steel covering almost the entire outer periphery, the nozzle body is formed of a non-fired refractory material, and a number of the nozzle main bodies are spaced apart in the axial and circumferential directions on the inner peripheral surface of the protective steel. Characterized in that the projections are provided, and each projection is cut into the outer peripheral portion of the nozzle body. 2. The slide gate according to claim 1, wherein a heat insulating coat that develops according to the temperature during use is interposed between the outer peripheral surface of the nozzle body and the inner peripheral surface of the protective skin. Under nozzle. 3. A nozzle body having a large diameter portion at an upper end portion,
In a method of manufacturing a lower nozzle for a slide gate comprising a protective steel covering almost the entire outer periphery, a lower die having a core rod erected is set on a mold frame capable of setting the protective steel with an upper end thereof up. Then, after setting a protective iron shell provided on the inner peripheral surface with a large number of protrusions separated in the axial and circumferential directions, refractory raw materials are charged into the mold, and then the upper mold is moved to the mold. A method for manufacturing a lower nozzle for a slide gate, comprising: setting a refractory raw material by setting the refractory material to a lower nozzle. 4. A nozzle body having a large diameter portion at an upper end portion,
In a method of manufacturing a lower nozzle for a slide gate comprising a protective iron cover covering substantially the entire outer periphery, a number of projections are provided on an inner peripheral surface of a lower die having a core rod erected in the axial and circumferential directions. A method for manufacturing a lower nozzle for a slide gate, comprising: setting a protective steel shell with its upper end downward, and then pouring a castable refractory into the protective steel shell. 5. The method for manufacturing a lower nozzle for a slide gate according to claim 3, wherein a heat insulating coating agent that develops depending on the temperature at the time of use is applied in advance to the inner peripheral surface of the protective steel shell. .