JP3479713B2 - Lower nozzle for slide gate and method of manufacturing the same - Google Patents

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 and a tundish, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a lower nozzle for a slide gate is vertically installed on a lower plate of a slide gate in order to guide a molten metal to a tundish or a mold, and an upper end portion attached to the lower plate has a large diameter portion. The nozzle body is composed of a fired or non-fired refractory, and a protective iron shell that covers almost the entire outer periphery of the nozzle body with mortar interposed. 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 that has been manufactured in advance, while applying the mortar to the entire inner circumferential surface of the protective iron shell, and then fit both. It is manufactured in combination.

[0003]

However, in the conventional lower nozzle for slide gate, it is difficult to prevent the expansion of the radial crack gap (axial gap) generated in the nozzle body during use, If the mortar is insufficiently filled, there is a problem that the protective iron shell is punctured with the expansion of cracks and leaks frequently. Moreover, since the nozzle body and the protective iron skin are manufactured by fitting them together with mortar interposed, a mortar coating process and a fitting process for both are required, which complicates the process and eventually increases the cost. There is. Therefore, it is a main object of the present invention to provide a lower nozzle for a slide gate and a method for manufacturing the same, which can prevent expansion of radial cracks in the nozzle body and can simplify the process.

[0004]

In order to solve the above-mentioned problems, a first slide gate lower nozzle of the present invention comprises a nozzle main body having a large diameter portion at its upper end and a protective iron skin covering almost the entire outer periphery thereof. In a lower nozzle for a slide gate consisting of, the nozzle body is formed of an unfired refractory material,
A large number of protrusions are provided on the inner peripheral surface of the protective iron skin so as to be separated from each other in the axial direction and the peripheral direction, and each protrusion is bite into the outer peripheral portion of the nozzle body. In the second lower nozzle for slide gate, in the first nozzle, a foaming coating agent that exhibits heat insulating properties depending on the temperature during use is interposed between the outer peripheral surface of the nozzle body and the inner peripheral surface of the protective iron shell. It is characterized by being equipped. On the other hand, the first method for manufacturing a lower nozzle for a slide gate is the method for manufacturing a lower nozzle for a slide gate, which comprises a nozzle body having a large-diameter portion at an upper end and a protective iron skin covering almost the entire outer periphery thereof. A lower mold with a core rod standing upright was set on a mold that allowed the protective iron skin to be set with the upper end facing up, and a large number of protrusions were provided on the inner peripheral surface in the axial and circumferential directions. The method is characterized in that, 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. The second slide gate lower nozzle manufacturing method is as follows.
In a method for manufacturing a lower nozzle for a slide gate, which comprises a nozzle body having a large-diameter portion at its upper end and a protective iron skin that covers almost the entire outer periphery of the nozzle body, a large number of protrusions are axially provided on a lower die having a core rod. And, the castable refractory is poured into the protective iron skin after the protective iron skin provided on the inner peripheral surface so as to be separated in the circumferential direction is set with the upper end portion facing downward. A third method for manufacturing a lower nozzle for a slide gate is the same as the first or second method, except that a foaming coating agent that exhibits heat insulation properties depending on the temperature during use is applied to the inner peripheral surface of the protective iron shell in advance. It is characterized by setting.

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

The projections on the inner peripheral surface of the protective iron skin are formed by overhanging or beading the protective iron skin with a punch or the like, welding a disc-shaped member to the protective iron skin, bending or cutting the protective iron skin, Alternatively, it is provided by welding an anchor stud to a protective iron skin.

The foaming coating agent, which exhibits heat insulation properties depending on the temperature of the lower nozzle when used , is applied to the inner peripheral surface of the protective iron shell by 0.1
Ru is applied to a thickness of ~1.0mm. As the foamable coating agent, in the case of an inorganic material, a raw material containing SiO ₂ , MgO, Al ₂ O ₃ (for example, vermiculite, andalusite, etc.) has a volume expansion coefficient of 50 to 500 times at a temperature of 500 to 1000 ° C. It becomes also the is used.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION 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 made of an unfired refractory made of an appropriate refractory material, and has a large diameter portion 2 at its upper end.
It is composed of a nozzle body 2 having a and a protective iron shell 3 covering almost the entire outer circumference thereof. A large number of projections 4 are provided on the inner peripheral surface of the protective iron skin 3 by axially forming the protective iron skin 3 with a punch or the like, and the protrusions 4 are appropriately separated in the axial direction and the circumferential direction. It is cut into the outer periphery of 2.

In the lower nozzle 1 having the above structure, even if a radial crack occurs in the nozzle body 2 during use, the axial movement of the nozzle body 1 is restrained by the respective projections 4, so that the crack is not generated. The expansion of the gap is prevented. Therefore, unlike the conventional one, the protective iron shell has a hole, and the molten metal does not leak out.

FIG. 2 is a front view in half section showing a second embodiment of the lower nozzle for a slide gate according to the present invention. The lower nozzle 5 has a foamable coating agent 6 between the outer peripheral surface of the nozzle body 2 and the inner peripheral surface of the protective iron shell 3 which exhibits heat insulation due to volume expansion due to temperature when the lower nozzle 5 is used. It is a costume. Since other configurations are the same as those of the first embodiment, the same components and the like are designated by the same reference numerals and the description thereof will be omitted.

[0011] In the lower nozzle 5 having the above configuration, other similar effects as those of the first embodiment, in use, originating
Due to the development of heat insulation due to the volume expansion of the foamy coating agent 6,
The binding force of the protective iron shell 3 to the nozzle body 2 is increased, and the heat insulating property of the lower nozzle 5 is improved. By increasing the heat insulating property, it is possible to prevent flicker due to the cooling of the molten metal near the outlet of the lower nozzle, and to prevent its oxidation due to the rise in the surface temperature of the protective iron shell 3.

In each of the above-described embodiments, the case where the protrusion 4 on the inner peripheral surface of the protective iron shell 3 is provided by the overhang molding of the protective iron skin 3 has been described, but the present invention is not limited to this. Instead, for example, like the protective iron skins 7, 8, and 9 shown in FIGS. 3, 4, and 5, a disk-shaped steel member is axially and circumferentially formed on the inner peripheral surface of the protective iron skin 7. To the protrusions 10 which are appropriately separated from each other and welded, or where the portions of the protective iron skin 8 which are appropriately separated in the axial direction and the circumferential direction are inwardly bent or cut and raised, or the protective iron skin 9 The protrusions 12 and the like may be formed by welding Y-shaped or V-shaped anchor studs to the inner peripheral surface at appropriate intervals 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, the protective iron shell 3 is placed on a mold 13 on which the upper end portion can be set upward, and the nozzle main body. A lower die 15 having a core rod 14 for forming two nozzle holes is set, and a large number of projections 4 are provided on the inner peripheral surface so as to be separated in the axial direction and the circumferential direction. coated cloth insulation coating agent 6 which express heat insulation by volume expansion due to temperature at the time of use on the inner peripheral surface at a thickness of 0.1~1.0mm
The protective iron skin 3 was set. Next, as shown in FIG. 7, after the refractory raw material 16 is put into the mold 13, as shown in FIG. 8, the upper mold 17 is set on the mold 13 and pressed at a required pressure, and after that, , Demold, dry and lower nozzle 5
Got

Therefore, in the method of manufacturing the lower nozzle 5 described above, the conventional mortar coating step for the nozzle body and the protective iron shell, the fitting step for both, and the mortar drying step are omitted.

The manufacture of the lower nozzle 5 is not limited to the method described above, and for example, as shown in FIG. 9, a core rod 18 for forming a nozzle hole of the nozzle body 2.
A plurality of protrusions 4 are provided on the inner peripheral surface of the lower mold 19 standing upright in the axial direction and the circumferential direction at a distance from each other, and the thermal insulation coat exhibits thermal insulation by volume expansion depending on the temperature when the lower nozzle 5 is used. agent 6 after the upper portion of the inner peripheral surface protective steel shell 3 was coated cloth <br/> in and set down at a thickness of 0.1~1.0mm a castable refractory in a protective steel shell 3 20 Then, the castable refractory material 20 was solidified, demolded, and dried to obtain the lower nozzle 5. Further, 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 iron shell 3.

[0016]

As described above, according to the first slide gate lower nozzle of the present invention, even if a radial crack occurs in the nozzle body during use, the nozzle body moves in the axial direction. Is restrained by the respective protrusions, so that the expansion of cracks can be prevented, and thus the occurrence of molten metal can be prevented. According to the second lower nozzle for the slide gate, in addition to the function and effect of the first one, the foamable coating is used during use.
The thermal expansion of the coating agent enhances the binding force of the protective iron shell to the nozzle body and the thermal insulation of the lower nozzle, which further suppresses the occurrence of cracks and the expansion of the gap, and also improves the durability. The life can be extended. On the other hand, according to the first and second slide gate lower nozzle manufacturing methods, the first slide gate lower nozzle can be obtained, and in addition to the conventional mortar coating step for the nozzle body and the protective iron shell, or both. Since the fitting process and the like can be omitted, the process can be simplified and the cost can be reduced. According to the third method for manufacturing the lower slide gate nozzle, the second lower nozzle for slide gate can be obtained in addition to the effects of the first and second methods.

[Brief description of drawings]

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

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

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

FIG. 4 is a front view, in half cross-section, of yet another protective iron shell in the lower nozzle for a slide gate according to the present invention.

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

FIG. 6 is a sectional view of a first 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. 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 of manufacturing the lower nozzle for the slide gate according to the present invention.

FIG. 9 is a cross-sectional view showing another example of the embodiment of the method for 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 iron skin 4 Protrusion 6 Foaming coating agent 7 Protective iron skin 8 Protective iron skin 9 Protective iron skin 10 Protrusion 11 Protrusion 12 Protrusion 13 Form 14 Core rod 15 Lower mold 16 Refractory raw material 17 Upper mold 18 Core rod 19 Lower mold 20 Castable refractory

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takaaki Hirano 1 Minamito, Ogaie-cho, Kariya city, Aichi Toshiba Ceramics Co., Ltd.Kariya factory (72) Keiko Okada 1-nanto, Ogakie-cho, Kariya city, Aichi Prefecture Toshiba Ceramics Co., Ltd. In the Kariya Plant (72) Inventor Takigawa Sei Ari Prefecture, Kariya City, Ogaie Town, 1st Nanto, Toshiba Ceramics Co., Ltd. In the Kariya Plant (56) Reference JP 10-24359 (JP, A) JP 11-138241 (JP) , A) JP-A-11-197824 (JP, A) JP-A-6-142899 (JP, A) JP-A-7-290422 (JP, A) Actually developed Sho-56-50564 (JP, U) Actually developed flat 5-51921 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22D 41/50 520 B22D 41/52 B22D 11/10 340

Claims (5)

(57) [Claims] 1. A nozzle body having a large diameter portion at an upper end thereof,
In a lower nozzle for a slide gate, which comprises a protective iron skin covering substantially the entire outer circumference thereof, the nozzle body is formed of an unfired refractory material, and a large number of the nozzle bodies are axially and circumferentially spaced on the inner peripheral surface of the protective iron skin. The lower nozzle for a slide gate, characterized in that each of the projections is provided, and each projection bites into the outer peripheral portion of the nozzle body. 2. A calling expressing thermal insulation the temperature in use between the outer peripheral surface and the inner peripheral surface of the protective steel shell of the nozzle body
The lower nozzle for a slide gate according to claim 1, wherein a foaming coating agent is interposed. 3. A nozzle body having a large diameter portion at an upper end portion,
In a method for manufacturing a lower nozzle for a slide gate, which comprises a protective iron skin covering almost the entire outer periphery thereof, a lower mold having a core rod set in a formwork capable of setting the protective iron skin with the upper end portion facing upward is set. In addition, after setting a protective iron skin provided on the inner peripheral surface with a large number of projections separated from each other in the axial direction and the circumferential direction, the refractory raw material is put into the mold, and then the upper mold is closed. A method for manufacturing a lower nozzle for a slide gate, comprising: 4. A nozzle body having a large-diameter portion at its upper end,
In a method of manufacturing a lower nozzle for a slide gate, which comprises a protective iron skin that covers almost the entire outer circumference, a plurality of protrusions 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, which comprises setting a protective iron skin with the upper end thereof facing down, and then pouring castable refractory into the protective iron skin. 5. The bottom for slide gate according to claim 3, wherein a foaming coating agent exhibiting heat insulating properties depending on the temperature during use is applied in advance to the inner peripheral surface of the protective iron shell. Nozzle manufacturing method.