JP2005118790A - Tundish nozzle for continuous casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly replace a lower nozzle without interrupting a casting process in an open nozzle type tundish nozzle exchanging apparatus, to easily prevent leakage of molten steel on a sliding surface of upper and lower nozzles, safely and To provide a tundish nozzle for continuous casting that enables efficient operation.
SOLUTION: The sliding surface of the lower nozzle has a polygonal shape having sides parallel to the sliding direction and sides perpendicular to the sliding direction on the front and rear sides of the sliding direction, and orthogonal to the sliding direction. In the direction, when the length of the sliding surface of the upper nozzle is at least partly larger than the length of the sliding surface of the lower nozzle and the centers of the nozzle holes of the upper and lower nozzles match The sliding surface of the upper nozzle is located behind the front side of the sliding surface of the lower nozzle.
[Selection figure] None

Description

  The present invention relates to a tundish nozzle used in continuous casting, and more particularly to a tundish nozzle for continuous casting that is provided at the bottom of a tundish and is suitably used for continuous casting of molten metal by an open nozzle system.

In continuous casting of steel, in order to continuously inject molten steel from the tundish into the mold, the molten steel is fed into the mold using a tundish nozzle provided at the bottom of the tundish.
Among the tundish nozzles, the simplest method is a so-called open nozzle method in which molten steel is dropped from an opening having a constant area at the bottom of the tundish.

  The open nozzle is made of a refractory material having excellent stability, corrosion resistance, and spalling resistance to molten steel such as zirconia. Since it becomes difficult to control the flow rate of the molten steel, for example, the opening is closed due to the generation of deposits, it is necessary to replace it with a new nozzle as appropriate.

Conventionally, for example, a tundish nozzle replacement device as described in Patent Document 1 has been used as a means for performing such replacement of the open nozzle without interrupting the casting process.
In the apparatus, the upper nozzle is fixed to the bottom of the tundish, and the lower nozzle is configured to be exchanged by being pushed forward along the guide rail in a lateral direction in contact with the upper nozzle. ing.

Moreover, as the shape of the upper and lower nozzles used in the same tundish nozzle replacement device as described above, for example, the shape shown in FIG. 8 has been conventionally used (see Patent Document 2).
In the nozzle described in Patent Document 2, the plate portions of the upper nozzle 11 and the lower nozzle 12 have the same shape, but the lower surface of the upper plate functions as a guide surface, and the lower plate to be replaced is disposed at the normal position. In order to prevent this, the upper and lower plate surfaces are set so that the angle in the horizontal plane is shifted around the nozzle hole 16 so that the upper and lower plate surfaces do not completely overlap.

Japanese Patent Laid-Open No. 10-286658 JP 2000-502594 A

However, in the configuration of the upper and lower nozzles as described above, when the molten steel flows down to the mold surface, the splash (splash) adheres to the exposed lower surface of the upper nozzle, and the lower nozzle is smoothly slid by the adhered matter. May be hindered from being replaced.
In addition, when the lower nozzle is replaced, the lower nozzle to be replaced rides on the deposits attached to the lower surface A of the upper nozzle in the forward direction of the feeding direction, and a gap is formed on the contact surface of the upper and lower nozzles, and flows out of the tundish. There is also a risk that the molten steel leaks from between the upper and lower nozzles.

  The present invention has been made to solve the above technical problem, and in an open nozzle type tundish nozzle exchanging device, the lower nozzle can be smoothly exchanged without interrupting the casting process, An object of the present invention is to provide a tundish nozzle for continuous casting that can easily prevent molten steel leakage on the sliding surface of the nozzle and enables safe and efficient operation.

The tundish nozzle for continuous casting according to the present invention is a tundish nozzle that slides the lower nozzle in contact with the lower surface of the upper nozzle attached to the bottom of the tundish in a certain horizontal direction and sequentially replaces it with another lower nozzle. The lower surface of the upper nozzle and the upper surface of the lower nozzle are slidable smooth surfaces, and the sliding surface of the lower nozzle is on the side parallel to the sliding direction, on the front and rear in the sliding direction, It is a polygonal shape having sides perpendicular to the sliding direction, and in the direction perpendicular to the sliding direction, the length of the sliding surface of the upper nozzle is at least partly the length of the sliding surface of the lower nozzle. And the sliding surface of the upper nozzle is located behind the front side of the sliding surface of the lower nozzle when the center of the nozzle hole of the upper and lower nozzles is in a state of being coincident with each other. To do.
By configuring the tundish nozzle as described above, when the lower nozzle is replaced, the splash attached to the sliding surface of the upper nozzle hinders smooth sliding of the lower nozzle or rides on the adhered matter and moves up and down. It is possible to prevent the molten steel from leaking due to a gap formed between the sliding surfaces of the nozzle.

In the continuous casting tundish nozzle, the shape of the sliding surface of the upper nozzle may be different from the shape of the sliding surface of the lower nozzle.
As described above, the shape of the upper nozzle and the shape of the lower nozzle need not be the same as long as the effect of preventing the adhesion of splash on the lower surface of the upper nozzle is obtained.

As described above, if the tundish nozzle for continuous casting according to the present invention is used, the lower nozzle can be replaced smoothly without interrupting the casting process in the open nozzle type tundish nozzle replacement device. Therefore, it is possible to simply prevent the molten steel from leaking on the sliding surface, and to operate safely and efficiently.
For this reason, if the tundish nozzle for continuous casting according to the present invention is used, maintenance is easy, the durability of the upper nozzle is improved, and as a result, the quality deterioration of the steel product is suppressed and the production efficiency is improved. Can contribute.

Hereinafter, the present invention will be described in more detail with reference to the drawings.
FIG. 1 schematically shows the structure of a tundish bottom portion provided with a tundish nozzle for continuous casting according to the present invention.
As shown in FIG. 1, in the tundish nozzle for continuous casting according to the present invention, the upper nozzle 1 is mounted on the bottom of a tundish 4 provided with a protective layer of a refractory material 5. A rail 3 is provided on the bottom lower surface of the tundish 4 so that the lower nozzle 2 contacts the bottom of the tundish 4 and slides in one direction. The lower surface of the upper nozzle 1 and the upper surface of the lower nozzle 2 are formed as slidable smooth surfaces.

When the molten steel flows out, it is used in a state where the centers of the upper and lower nozzle holes 6 coincide with each other, and when the flow rate of the molten steel is changed or the lower nozzle needs to be replaced, those having different hole diameters, or, A new lower nozzle 2 is sent out from the left side in FIG. 1 by a hydraulic cylinder (not shown) or the like, and the original lower nozzle 2 ′ is pushed out in the direction of the arrow and replaced.
Such replacement operation of the lower nozzle is repeatedly performed as necessary.

2 to 7 schematically show the shapes of the sliding surfaces of the upper and lower nozzles according to the present invention. 2 to 7 show the shape of the sliding surface when viewed from the lower surface side of the lower nozzle in a state where the centers of the nozzle holes 6 of the upper and lower nozzles match, and the arrow indicates the sliding of the lower nozzle 2. Shows direction.
In FIG. 2, the sliding surface of the upper nozzle 1 is a horizontally long rectangle with respect to the sliding direction, and the sliding surface of the lower nozzle 2 is a vertically long rectangle with respect to the sliding direction.
The upper and lower nozzles have different rectangular shapes.

In FIG. 3, the sliding surface of the upper nozzle 1 is a pentagon, and the sliding surface of the lower nozzle 2 is a square.
Moreover, in FIG. 4, the sliding surface of the upper nozzle 1 is a hexagon, and the sliding surface of the lower nozzle 2 is a square.
In FIG. 5, the sliding surface of the upper nozzle 1 is a partial circle obtained by cutting a circular front portion in accordance with the shape of the front portion of the sliding surface of the lower nozzle 2, and the sliding surface of the lower nozzle 2 is a square. It is.
In FIG. 6, the sliding surface of the upper nozzle 1 is an ellipse that is horizontally long with respect to the sliding direction, and the sliding surface of the lower nozzle 2 is a rectangle that is vertically long with respect to the sliding direction.
In FIG. 7, the sliding surface of the upper nozzle 1 is a rhombus that is horizontally long in the sliding direction, and the sliding surface of the lower nozzle 2 is a square.

As shown in FIGS. 2 to 7, in the tundish nozzle for continuous casting according to the present invention, the sliding surface of the lower nozzle 2 is the side parallel to the sliding direction and the front in the sliding direction. And on the rear side, there is a side perpendicular to the sliding direction.
Since the sliding surface of the lower nozzle is formed in such a shape, the lower nozzle can be stably slid on the rail when replacing the lower nozzle, and the original lower nozzle to be replaced and a new nozzle are replaced. It is possible to prevent molten steel leakage from the gap between the two.

Further, in the direction orthogonal to the sliding direction, the length of the sliding surface of the upper nozzle 1 is formed such that at least a part thereof is larger than the length of the sliding surface of the lower nozzle 2. .
Thus, by forming the sliding surface of the upper nozzle so as to have a portion that does not always contact the lower nozzle, this portion can be fixedly mounted on the bottom surface of the tundish bottom by clamping or bolting. it can. For this reason, the member for mounting and fixing the upper nozzle does not prevent the lower nozzle from sliding.

Further, when the centers of the nozzle holes 6 of the upper and lower nozzles are aligned, the sliding surface of the upper nozzle 1 is formed so as to be located behind the front side of the sliding surface 2 of the lower nozzle. Yes.
By configuring the upper and lower nozzles in this way, the front portion of the sliding surface of the upper nozzle is exposed to the mold surface, so that splash from the mold surface can be prevented when the molten steel flows out.
Therefore, when the lower nozzle is replaced, the splash adhered to the upper nozzle sliding surface prevents the lower nozzle from sliding smoothly, or climbs on the deposit and creates a gap between the upper and lower nozzle sliding surfaces. It is possible to prevent the molten steel from leaking.

  As shown in FIGS. 2 to 7, the tundish nozzle for continuous casting according to the present application has the shape of the upper nozzle and the shape of the lower nozzle as long as the effect of preventing the adhesion of splash on the lower surface of the upper nozzle is obtained as described above. Need not be the same.

  The sliding surfaces of the upper and lower nozzles are formed so that the corners are rounded, as shown in FIGS. 2 to 7, from the viewpoint of preventing breakage and cracks due to contact during nozzle replacement, etc. It is preferably formed by chamfering.

  By configuring the upper and lower nozzles in the tundish nozzle as described above, even when the amount of molten steel flowing out of the tundish is changed, it is possible to prevent molten steel leakage near the nozzle, Since the replacement can be performed safely and sequentially, the casting process can be performed for a long time without interruption.

It is the longitudinal section showing the outline of the tundish nozzle for continuous casting concerning the present invention typically. It is the figure which showed typically the one aspect | mode of the shape of the sliding surface of the upper-lower nozzle which concerns on this invention. It is the figure which showed typically the other aspect of the shape of the sliding surface of the upper-lower nozzle which concerns on this invention. It is the figure which showed typically the other aspect of the shape of the sliding surface of the upper-lower nozzle which concerns on this invention. It is the figure which showed typically the other aspect of the shape of the sliding surface of the upper-lower nozzle which concerns on this invention. It is the figure which showed typically the other aspect of the shape of the sliding surface of the upper-lower nozzle which concerns on this invention. It is the figure which showed typically the other aspect of the shape of the sliding surface of the upper-lower nozzle which concerns on this invention. It is the figure which showed typically an example of the shape of the sliding surface of the conventional upper-lower nozzle.

Explanation of symbols

1 Upper nozzle 2, 2 'Lower nozzle 3 Rail 4 Tundish 5 Refractory material 6 Nozzle hole

Claims (2)

A tundish nozzle that slides the lower nozzle in contact with the lower surface of the upper nozzle attached to the bottom of the tundish in a certain horizontal direction and sequentially replaces it with another lower nozzle,
The lower surface of the upper nozzle and the upper surface of the lower nozzle are slidable smooth surfaces,
The sliding surface of the lower nozzle is a polygonal shape having sides that are parallel to the sliding direction, and sides that are orthogonal to the sliding direction on the front and rear sides of the sliding direction,
In the direction orthogonal to the sliding direction, the length of the sliding surface of the upper nozzle is at least partly larger than the length of the sliding surface of the lower nozzle,
The continuous casting tank is characterized in that when the center of the nozzle hole of the upper and lower nozzles is coincident, the sliding surface of the upper nozzle is behind the front side of the sliding surface of the lower nozzle. Dish nozzle.   2. The tundish nozzle for continuous casting according to claim 1, wherein the shape of the sliding surface of the upper nozzle is different from the shape of the sliding surface of the lower nozzle.

Images