JPH0724567A - Nozzle of molten steel outflow control device - Google Patents

Abstract

PURPOSE:To prevent the diffusion of molten steel to the outer diameter and to restrain the stickness of metal to the inner wall of tundish pouring tube, etc., in a lower nozzle, etc., at a sliding gate for ladle in continuous casting. CONSTITUTION:In the lower nozzle 3 arranged at the sliding gate 2 for ladle in the continuous casting, this nozzle hole 9 is constituted so that the inner diameter d2 at the discharging side is a little smaller than the inner diameter d1 at the flow-in side and this inner diameter is continuously reduced toward the discharging side from the flow-in side, and forms the reverse conical shape having tapered angle theta. The movement directed in the flowing center direction to the molten steel flowing-down direction (vertical direction) is generated in the flowed-down molten steel near the inner wall surface of the nozzle hole, and the flowed-down molten steel is converged and the diffusion of molten metal to the outer direction is restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outflow rate control device for injecting a molten material such as molten steel while controlling the outflow rate.
In particular, the present invention relates to a lower nozzle of a sliding nozzle device that controls a molten steel outflow amount when pouring molten steel from a ladle into a tundish in continuous casting.

[0002]

2. Description of the Related Art For example, in continuous casting, when pouring molten steel from a ladle for transporting molten steel into a tundish for continuous casting, a sliding nozzle device is used as an outflow adjusting device.

As shown in FIG. 5, this sliding nozzle device is installed in the lower part of the ladle L, and the upper nozzle 1, the upper plate 2a, the slide plate 2b, and the like in order from the top.
It consists of a sliding gate 2 composed of a lower plate 2c, a lower nozzle 3 for rectification, and a slide plate 2b is slid by a hydraulic cylinder 4 to open / close a molten steel passage hole 5 communicating vertically and adjust the flow rate. .

Further, as shown in FIG. 6, in order to prevent the oxidation of the molten steel during the injection of the molten steel, a so-called cap (cover plate) 6 is attached to the lower end of the lower nozzle 3, and the tundish T has an upper end. A refractory pouring pipe 7 is provided as a tubular member for sealing, which is in contact with the Jinsha 6 and whose lower end is immersed in the surface of the tundish.

Conventionally, the nozzle holes 8 formed in the lower nozzle 3 of such a sliding nozzle device have the same inner diameter from the upper inflow side to the lower discharge side, and the inner wall of the nozzle is also about 90 ° with respect to the horizontal. It is a straight surface (see FIGS. 4 and 5).

[0006]

However, in the conventional lower nozzle as described above, the molten steel itself is a viscous fluid, so that the flow along the inner wall of the nozzle hole is increased as shown in FIG. However, if the corner portion between the inner wall and the lower end surface of the lower nozzle 3 is missing outward due to melting damage, heat shock, etc., the molten steel flow F has an angle that spreads from the downward direction. And expand its width outward.

As a result, as shown in FIG. 6, the molten steel is scattered on the inner wall of the injection pipe 7 provided in the tundish T, and adheres and grows as a metal a, which is stable due to the obstruction of the flow of the injected molten steel and scattering. Can not be injected. Further, in the worst case, the nozzle hole is closed. That is, in the conventional nozzle, a phenomenon that cannot be avoided occurs depending on the number of times of use.

In order to prevent such metal adhesion,
It is necessary to develop a nozzle refractory that does not change the shape of the lower end of the nozzle hole of the lower nozzle, or to set a shape that does not increase the spread width of molten steel even if the shape changes.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent the molten steel from diffusing outward at the lower end of the nozzle by changing the shape. It is to provide a nozzle for an outflow amount adjusting device of molten steel or the like.

[0010]

Means for Solving the Problems] The present invention, in such lower nozzle provided in the ladle for the sliding gate in the continuous casting, as shown in FIG. 1, the nozzle hole of the nozzle, than the inner diameter d ₁ of the inflow-side Also, the inner diameter d ₂ on the discharge side is slightly smaller, and the inner diameter is continuously reduced from the inflow side toward the discharge side to form an inverted conical nozzle hole.

The angle θ of the inner wall of the nozzle hole with respect to the vertical line is
It depends on casting conditions or nozzle length, but it is 0.5
The range of ˜6.0 ° is preferable. When the angle θ is small, it becomes insufficient to change the flow direction, and when the angle θ is large, the required discharge amount cannot be secured,
It affects the casting operation.

[0012]

With the above structure, as shown in FIG. 2 (b), the nozzle hole is smoothly throttled from the inflow side to the discharge side, so that the molten steel flows downward in the molten steel near the inner wall surface of the nozzle hole. A motion toward the center of the flow with respect to the (vertical direction) is generated, and the molten steel flowing down converges, and the outward scattering at the outer peripheral portion of the molten steel melt can be greatly reduced. Further, even when the lower end of the nozzle is melted, the movement direction of the surface of the flowing molten steel is directed to the center of the flowing molten steel, so that the diffusion of the molten steel in the outward direction is suppressed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to an illustrated embodiment. This is an example applied to a lower nozzle of a sliding gate of a ladle in continuous casting.
The same parts as those of the related art are designated by the same reference numerals.

As shown in FIG. 1, the nozzle hole 9 in the lower nozzle 3 of the sliding gate 2 is configured such that the inner diameter d ₂ of the lower outlet is slightly smaller than the inner diameter d ₁ of the upper inlet, and the inner diameter is lowered. The shape is an inverted cone that continuously and smoothly changes toward the end. The taper angle θ formed by the vertical line on the inner wall surface of the nozzle hole 9 is an angle that spreads upward.

In the above structure, as shown in FIG. 2B, the surface flow direction of the molten steel flow F in the nozzle hole 9 can be directed toward the center of the nozzle hole, and the lower end portion of the lower nozzle 3 can be directed. The diffusion width of molten steel in can be significantly reduced compared to the conventional straight tube type nozzle 8 (see Fig. 2 (a)), and the lower corner of the lower nozzle 3 is melted and damaged in the outward direction. The diffusion of the flow to is suppressed. That is, in FIG. 2, α ₁ > α ₂ , and the metal a which is scattered and adheres to the inner wall of the refractory injection pipe 7 located at a predetermined distance a
The amount of adhering is suppressed.

FIG. 3 is a graph showing the relationship between the casting time and the amount of metal adhered to the inner wall of the injection pipe when the angle θ is changed. The amount of molten steel flowing down is 9.0-12.0 [T /
Minutes]. As is clear from this figure, the adhesion amount is large in the conventional straight pipe type, but in the present invention, the adhesion amount is reduced to about 1/3 of the conventional amount.

Further, from the figure, when θ is 0.4, the effect of reducing the adhered amount is not sufficient, so 0.5 or more is desirable. The upper limit of θ is determined by the passing steel amount, nozzle shape, and size, but is set to about 6.0 so that the required discharge amount can be secured.

Although the lower nozzle of the sliding gate for ladle in continuous casting has been described above, the present invention is not limited to this, and the present invention can be applied to the nozzle of the outflow control device for other molten material containers. There is no end.

[0019]

As described above, according to the present invention, in the lower nozzle or the like in the sliding nozzle device installed in the ladle for steel making, the nozzle hole is changed from the conventional constant inner diameter to
Since the discharge side has an inverted conical shape with an inner diameter smaller than that of the inflow side, it is possible to prevent the generation and diffusion of molten steel droplets from the downward direction to the outward direction at the discharge end.
It is possible to suppress the adhesion of the metal to the inner wall of the injection pipe provided in the tundish inflow portion and the growth due to the adhesion.

The amount of the metal adhered is reduced to a fraction of that of the conventional one, and as a result, the flow of the metal during the injection is not obstructed or scattered due to the growth of the metal, which occurs during the continuous casting. It is possible to stably provide many heat cycles.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a nozzle according to the present invention.

FIG. 2 shows a discharge state of a molten steel flow, (a) is a case of a conventional straight pipe type nozzle, and (b) is a case of the nozzle of the present invention.

FIG. 3 is a graph showing the relationship between the casting time and the amount of deposit on the inner wall of the injection pipe when the angle of the inner wall surface of the nozzle hole is changed.

FIG. 4 is a schematic view showing a discharge state of a conventional molten steel flow.

FIG. 5 is a sectional view showing a sliding nozzle device in a ladle.

FIG. 6 is a schematic sectional view showing a ladle and a tundish in continuous casting.

[Explanation of symbols]

 L Ladle T Tundish 1 Upper nozzle 2 Sliding gate 2a Upper plate 2b Slide plate 2c Lower plate 3 Lower nozzle 4 Hydraulic cylinder 5 Molten steel passage hole 6 Jinkasa 7 Injection pipe 8 Nozzle hole (conventional) 9 Nozzle hole (present invention)

Claims (1)

[Claims] 1. A nozzle of an outflow amount control device provided in a lower portion of a container for containing molten steel or the like for controlling the outflow amount of molten steel or the like, wherein a nozzle hole of the nozzle has an inner diameter on a discharge side rather than an inner diameter on an inflow side. Is small, and the inner diameter is continuously reduced from the inflow side toward the discharge side.