JPH07124720A - Nozzle for continuous casting - Google Patents

Abstract

PURPOSE:To improve the inside quality and surface quality of a cast slab by providing a cap having discharge hole directed in the tangential direction of the pouring hole having bottom at the wall part to form pouring bottomed hole. CONSTITUTION:In a nozzle main body 1, a bulged part 3 is arranged in the upper part 3, the inside is formed to half sphere, communicating to a pouring hole 5. A cap 2 is provided at the upper end of the nozzle main body 1. In the cap 2, a thick thickness part 8 is formed in center, a bottomed hole 9 is formed therein. In a wall part forming a molten metal pouring bottomed hole 9, four discharge holes 11 directed in the tangential direction of the molten metal pouring bottomed hole 9 are formed at equal interval. The inside of the bulged part 3 at upper part of nozzle main body 1 may be a reverse conic shape in cross section. By this method, at increased casting speed, molten metal is evenly poured into mold without being unevenly flowed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting nozzle, and more particularly to a continuous casting nozzle for uniformly pouring molten metal into a mold from a tundish or ladle.

[0002]

2. Description of the Related Art In continuous casting, an immersion nozzle is generally used as a nozzle for continuous casting, and the immersion nozzle is attached to a slide nozzle attached to the outer bottom of the tundish to mold the tundish. Is being poured.

By the way, in continuous casting, when the casting speed is increased to improve the productivity, the amount of the molten metal passing through the immersion nozzle leading from the tundish to the mold increases, so that the immersion nozzle moves into the mold. When the molten metal is discharged, the speed of the molten metal discharged into the mold increases and
The direction in which the molten metal is discharged tends to be biased in one direction, and the molten metal cannot be discharged uniformly. As a result, uneven flow of the molten metal occurs in the mold, and inclusions and powder are trapped inside the mold, which deteriorates the internal quality of the slab. Further, the fluctuation of the molten metal surface in the mold becomes large, which deteriorates the surface quality of the slab. Further, it has been conventionally known that there is a problem that nozzle clogging easily occurs in the immersion nozzle.

As a solution to the above problems, it is conceivable to install an electromagnetic stirrer around the immersion nozzle to swirl the molten metal, but it is necessary to dispose the electromagnetic stirrer between the tundish or the ladle and the mold. Therefore, there are restrictions on equipment. Also, since the slide nozzle is throttled to adjust the pouring amount, the molten metal flow from the slide nozzle to the dipping nozzle is biased to one side of the dipping nozzle, making it difficult to make uniform contact between the inner surface of the dipping nozzle and the molten metal It is assumed that there is a problem that is difficult to obtain.

The present invention was made on the basis of the above circumstances, and an object thereof is to effectively impart a swirling flow to a molten metal without borrowing an external force and to prevent the molten metal from being drifted into a mold. The present invention provides a nozzle for continuous casting capable of uniformly pouring molten metal.

[0006]

In order to achieve the above object, the nozzle for continuous casting according to the present invention has an upper part of a pouring hole having an inverted conical or hemispherical cross section, and a central part at the upper end thereof. A lid is provided with a bottomed hole for pouring molten metal in a portion, and a wall portion forming the bottomed hole for pouring molten metal is provided with a discharge hole oriented tangentially to the bottomed hole for pouring molten metal.

[0007]

In the above construction, the upper portion of the pouring hole is formed in an inverted conical shape or a hemispherical shape in cross section, and the wall portion forming the bottomed pouring hole of the lid provided at the upper end of the pouring hole is filled with the pouring liquid. Since the discharge hole is formed in the tangential direction of the bottomed hole for use, when pouring, swirling flow can be easily applied to the molten metal discharged from the discharge hole by using the inner wall surface of the inverted conical or hemispherical section as a guide. Can be formed. Further, since this swirl flow flows downward in the lower pouring hole, uneven flow in the pouring hole is eliminated, the molten metal can be uniformly poured into the mold, and nozzle clogging can be prevented. Further, even if the casting speed is increased, the molten metal can be poured uniformly without being unevenly flowed into the mold, so that the fluctuation of the molten metal surface in the mold can be suppressed, and the inclusion or inclusion of powder can be reduced. Internal quality of the slab,
Both the surface quality can be improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is an explanatory view of a continuous casting nozzle according to the present invention, in which a is a sectional view of the whole and b is
[Fig. 6] is a sectional view taken along line X-X of a. In the figure, 1 is a nozzle body and 2 is a lid.

The nozzle body 1 has a bulge 3 at the top,
The inside 4 of the bulging portion 3 is formed in a hemispherical shape and continues to the pouring hole 5. Further, it has a discharge hole 6 in the lower part, and the molten metal flowing down through the pouring hole 5 is discharged to the mold 7.

The lid 2 has a thick portion 8 formed at the center thereof, and a bottomed hole 9 for pouring is formed in the thick portion 8 as well as the bottomed hole 9 for pouring. Four discharge holes 11 are formed in the wall portion 10 at equal intervals in the tangential direction of the bottomed hole 9 for pouring. Then, it is attached to the upper end of the bulging portion 3 of the nozzle body 1 via a flange portion 12 formed on the outer periphery.

The continuous casting nozzle having the above structure is used for continuous casting by mounting the lower nozzle 15 on the slide nozzle 14 mounted on the outer bottom of the tundish 13. As a result, during casting, the molten metal that flows down from the tundish 14 is discharged from the discharge hole 11 into the hemispherical interior 4 and becomes a swirling flow as shown by the arrow 16 in FIG. Then, this swirl flow is flowed down in the lower pouring hole 5 and discharged from the discharge hole 6 to the mold 7. In this way, since the molten metal flows down while swirling in the pouring hole 5 and is discharged to the mold 7 from the discharge hole 6, uneven flow in the pouring hole 5 is eliminated and the molten metal is uniformly poured into the mold 7. be able to. Further, since the molten metal can be uniformly poured into the mold 7 in this way, fluctuations in the molten metal surface within the mold 7 can be suppressed, inclusion of inclusions and powder can be reduced, and in turn, Both internal quality and surface quality can be improved.

(Embodiment 2) FIG. 2 is a sectional view of a nozzle for continuous casting according to another embodiment of the present invention. What is shown in this figure has the same configuration except that the shape of the inside 4 of the bulging portion 3 in the nozzle for continuous casting shown in the first embodiment is formed into an inverted conical shape. Even if the shape of the inside 4 of the bulging portion 3 is formed in an inverted conical shape in this way, the slide nozzle 14 attached to the outer bottom of the tundish 13 and the lower nozzle 15 are formed as in the continuous casting nozzle of the first embodiment. Can be used for continuous casting with the interposition of, and the same operation and effect can be obtained.

Incidentally, by using the continuous casting nozzles shown in Examples 1 and 2 and a conventional reverse Y type nozzle for comparison, a slab of low carbon aluminum killed steel (230 m
m × 1500 mm) continuous casting (casting speed 2.0 m / min) was carried out, and changes in the molten metal level in the mold, nozzle clogging, surface quality, and inclusions were investigated. The results are shown in Table 1.

[0015]

[Table 1]

[0016]

As described above, according to the nozzle for continuous casting according to the present invention, the inner wall having the inverted conical or hemispherical cross section is used as a guide for the molten metal discharged from the discharge hole during pouring. A swirling flow can be easily formed. In addition, since the molten metal flows down in the lower pouring hole with this swirling flow,
Uneven flow in the pouring hole is eliminated, so that the molten metal can be uniformly poured into the mold, and nozzle clogging can be prevented. Further, even if the casting speed is increased, the molten metal can be poured uniformly without being unevenly flowed into the mold, so that the fluctuation of the molten metal surface in the mold can be suppressed, and the inclusion or inclusion of powder can be reduced. It is possible to improve both the internal quality and the surface quality of the slab.

[Brief description of drawings]

FIG. 1 is an explanatory view of a nozzle for continuous casting according to the present invention, in which a is an overall sectional view and b is an XX sectional view of a.

FIG. 2 is a sectional view of a nozzle for continuous casting according to another embodiment of the present invention.

[Explanation of symbols]

1: Nozzle body 2: Lid
3: Swelling part 4: Inside 5: Molten hole
6: Discharge hole 8: Thick part 9: Bottom hole for pouring 1
0: Wall 11: Discharge hole 12: Flange

Claims (1)

[Claims] 1. An upper part of the pouring hole is formed in an inverted conical shape or a hemispherical shape in cross section, and a pouring bottomed hole is formed at the center of the upper end and the pouring bottomed hole is formed. A nozzle for continuous casting, characterized in that the wall is provided with a lid having a discharge hole directed in a tangential direction of a bottom hole for pouring molten metal.