JPH03180254A - Device for pouring molten metal in continuous casting machine - Google Patents

Abstract

PURPOSE:To prevent the development of shell by constituting spouting hole in a pouring nozzle with one pair of inclined side opening hole parts and lower opening hole part and integrated outlet shape of both opening parts to dog-bone shape and setting the outlets in both opening parts onto almost the same plane. CONSTITUTION:The spouting hole in the pouring nozzle 20 is constituted with one pair of side opening parts 21 inclined toward short aides 2 in mold and the lower opening hole part 22 connected with the above and directed to just lower part of the nozzle 20. Then, the outlet shape of spouting hole integrating the side opening hole parts 21 and the lower opening hole part 22 is constituted as the dog-bone shape under observing in the developing shape to crossing plane at right angle of the nozzle. Further, the outlet in the side opening hole parts 21 and the lower opening hole part 22 are set at almost the same plane. By this method, the good cast slab without any crack can be cast.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pouring device for a continuous casting machine, and particularly for a continuous casting machine having a fan-shaped molten metal pool, such as a twin-belt continuous casting machine or a twin-drum continuous casting machine. The present invention relates to a pouring device suitable for a continuous casting machine that performs casting using a type of mold.

[Conventional technology]

Continuous casting machines that use narrowing molds, such as twin-belt continuous casting machines or twin-drum continuous casting machines that have fan-shaped molten metal pools, have a short side dam called a side dam that shapes the short side of the slab. If a solidified shell is formed on the side mold, it may cause breakout or deteriorate the quality of the short side of the slab, so every effort is made to prevent the formation of a shell on the side dam. Various methods have been proposed to prevent the formation of a shell in the side dam, such as embedding a heater in the refractory and heating it. However, the most economical method is
As described in Japanese Patent Publication No. 296944, this is a method of heating a side dam by applying a molten metal jet stream from a pouring nozzle to a side dam. That is, in this publication, in addition to the narrow opening that supplies molten metal to the center of the molten metal pool, inclined openings are provided on both sides of the molten metal pool, and the poured molten metal heats the side dam. This prevents the formation of a shell on the surface.

[Problem to be solved by the invention]

In a squeeze type twin belt continuous casting machine or a twin drum continuous casting machine, the poured molten metal forms a fan-shaped pool. The amount of molten metal stored in this fan-shaped pool increases approximately in proportion to the square of the depth of the fan-shaped pool.

However, if the amount of this molten metal pool is large, the molten metal once poured will stay here for a long time and will become too cold. If the molten metal cools too much in this way, shells are likely to form on the fan-shaped refractory surface or around the nozzle, leading to casting troubles.

In addition, since the depth of the fan-shaped pool is large, the length of the fan-shaped refractory is also long, and it becomes difficult for the lateral inclined flow to eject a colliding flow onto the surface of the fan-shaped refractory.

From the above points, it is desirable to make the depth of the fan-shaped weld pool as shallow as possible.

On the other hand, the nozzle disclosed in Japanese Patent Application Laid-Open No. 62-296944 has openings for the side flow and the downward flow at different levels, which is disadvantageous in terms of reducing the depth of the fan-shaped pool as described above. be.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pouring device for a continuous casting machine that can appropriately heat the short side mold surface and reduce the depth of the fan-shaped molten metal pool.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a pouring device for a continuous casting machine that manufactures plate materials by continuously cooling and solidifying molten metal, which has a pouring nozzle and directs the ejection hole toward the short side mold. The jet is composed of a pair of side openings that are inclined at the same angle, and a lower opening that is continuous with these and faces directly below the nozzle, and that the side openings and the lower opening are integrated. The exit shape of the hole is formed into a dogbone shape when viewed from the developed shape with respect to the nozzle orthogonal plane, and the exits of these side openings and the lower opening are arranged on substantially the same plane.

Preferably, the upper part of the pouring nozzle has a round channel, and the lower part, which is immersed in the molten metal, has a flat, narrow channel.

Preferably, the diameter of the round flow path in the upper part of the nozzle is reduced to a cone shape near the ejection hole, and the dogbone-shaped opening is connected to this.

The present invention further provides a narrowing type continuous casting machine characterized by being equipped with the above-mentioned pouring device.

In this case, preferably, the side openings are such that the position where the center of the jet flowing down from the side openings in an inclined manner collides with the side refractories is at the narrowest part of the fan-shaped molten metal pool from the molten metal surface. The distance from the hot water level to H is 0.2H to 0.9H.

[Effect]

Since the outlet of the pouring nozzle of the present application has a dog bone shape, the flow of the molten metal is as follows.

That is, since the side openings are inclined toward the side dam, the ejected flow can flow in an inclined manner, and the flow can be applied to a portion of the side dam at a desired height. Then, from the point where it collides with the side dam, the jet stream splits into upper and lower parts and flows along the wall of the side dam.

The molten metal pool in the squeezing mold is fan-shaped and narrow at the bottom, so the flow rate to the bottom is restricted, and the upward flow rate increases despite the inclined flow. Therefore, the side dam wall surface is sufficiently heated not only in the downward direction but also in the upward direction.

Since the outlet shape of the ejection hole is a dogbone shape, the lower opening is a narrow slit-shaped opening.
Since the passage is constricted, the flow rate directly below the nozzle is restricted, resulting in a weak flow. Therefore, this is prevented from flowing down and hitting the lower narrow gap of the fan-shaped pool at a strong flow velocity, thereby reducing the problem of re-dissolving the shell. In addition, since the slit-shaped opening in the lower opening is connected to the side opening, the downward flow becomes a weak jet flow that is uniform over the entire area of the narrow narrow gap in the plate width direction. Therefore, even if the shell is melted by the ejected flow, the amount is small and acts uniformly over the entire width direction, so that uneven shell thickness distribution will not occur.

Furthermore, because of this downward flow, a downward flow is generated as a secondary flow at the molten metal surface near the nozzle, so that the molten metal does not stay at the molten metal surface and the shell is prevented from adhering to the nozzle.

In addition, by arranging the ejection holes of the pouring nozzle in the shape of a dog bone on almost the same plane, the lower part of the pouring nozzle that is immersed in the molten metal is shaped to have a flat and narrow flow path. This makes it possible to reduce the immersion depth of the nozzle. Therefore, the depth of the fan-shaped molten metal pool can be made shallow, and the residence time of the molten metal in the molten metal pool can be shortened. That is, overcooling of the molten metal in the fan-shaped pool can be prevented, and defective shell formation can be eliminated.

By reducing the diameter of the round channel at the top of the nozzle into a conical shape near the nozzle hole, and connecting the side and lower openings of the dogbone shape to this, the nozzle can be manufactured by pressing or casting. The shape of the child can be simplified and the nozzle can be manufactured easily.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 1 to 3. This example describes the present invention in Japanese Unexamined Patent Publication No. 59-19915.
This is Fuchi applied to the narrowing twin belt continuous casting machine described in No. 1.

In Figures 1 to 3, the twin-belt continuous casting machine has a pair of belts 1 that shape the long sides of the slab, and a pair of side dams 2 that shape the short sides of the slab. In the continuous draw casting machine, the pair of belts 1 are wound around guide rollers 3 and guided so that the pouring portion becomes fan-shaped, and a fan-shaped molten metal pool 4 is formed in the pouring portion.

As shown in the cross section in the width direction of FIG. 1, the side dam 2 is constructed with a heat insulating refractory material 5 in this part because it is not possible to pull out the slab downwards when a shell is formed using the four parts of the fan-shaped pool. be done. The lower part is constituted by a mold 6 made of a copper member so that the short side shell is cooled and shaped after the curved part changes to the parallel part. This copper member mold 6 is filled with cooling water A.
From there, it flows to B and is cooled.

As shown in Fig. 2, molten metal 8 is fed into the fan-shaped pool 4 formed by a pair of belts 1 and side dams 2 through an open nozzle 9, and the amount of the molten metal is controlled by the sliding valve ↓0. It is adjusted and poured. The sliding valve 10 consists of two fixed plates 11 and 12;
A plate 14 that moves within two plates with a cylinder 13
It consists of And these plates cover 15
It is tightened. The molten metal adjusted by this sliding valve 10 then flows down the pouring nozzle 20 of this embodiment,
Hot water is poured into the fan-shaped pool 4.

This kind of continuous casting machine has a thickness of 20 to 50 mm and a width of 700 mm.
A plate-shaped slab 40 of ~1660 mm is formed at a speed of about 10 m/square.

The pouring nozzle 20 of this embodiment has a spouting hole consisting of a pair of side openings 21 inclined in the direction of the refractory 5 and a lower opening 22 continuous with the side openings 21 and facing directly below the nozzle. As can be seen from FIG. 3, the outlet shape of the ejection hole, which is a combination of these openings, is a dogbone shape when viewed from a plane perpendicular to the nozzle, and each opening 21.2
The two outlets are arranged approximately on the same plane.

Further, the upper part of the pouring nozzle 20 has a round channel 23 having a diameter φD, but at the ejection hole part that is immersed in the molten metal, this channel is reduced to a conical channel 24 with a diameter of φd. , to which dogbone-shaped openings 21 and 22 are connected. Furthermore, the nozzle shape of this part is also different from the flow path 24 and the open part 21.
．． It is formed into a flat shape to match the shape of 22.

Such a structure of the pouring nozzle 20 was obtained as a result of repeated various casting experiments and repeated considerations by the inventor of the present application. That is, the inventor of the present application has found that in the draw casting in which casting is performed while changing the shape from a fan-shaped pool to a parallel shape as described above, the preferable conditions regarding the pouring device are as follows.

(1) In order to prevent the formation of a solidified shell on the heat insulating refractory material 5 of the fan-shaped pool 4 portion shown in Fig.
The jet stream should be able to sufficiently heat the refractory.

(2) The downward flow from the pouring nozzle is a fan-shaped molten metal pool 4
The long side shell should not be re-dissolved by colliding with the lower narrow gap, and should have a uniform effect over the entire width direction.

(3) Stagnation occurs on the surface of the fan-shaped molten metal pool 4 and no shell is formed. This is especially formed around the nozzle 20 and tends to grow.

(4) If the amount of molten metal in the fan-shaped pool 4 is large, the nozzle 2
The molten metal poured from zero stays here for a long time, and shells are formed in unnecessary places, such as the side dam refractories 5 mentioned in item (1) and the molten metal surface mentioned in item (3). It becomes easier. Therefore, the nozzle shape must be such that the depth of the molten metal pool can be made as shallow as possible.

The pouring nozzle 20 satisfies all of the above conditions.

That is, in the pouring nozzle 20 of this embodiment, the diameter of the measuring hole 21 of the dogbone-shaped spouting hole is large and inclined, so that the pouring nozzle 20 has a large diameter and is inclined. The ejected flow becomes a strong inclined flow 30 and collides with the refractory 5 surface, which creates a downward flow 3↓ and an upward flow 3.
It separates into two parts, each flowing while heating the refractory wall surface.

At this time, since the molten metal pool 4 is fan-shaped and narrow at the bottom, the downward flow is restricted, and a sufficient amount of upward flow flows despite the inclined flow. Therefore, the side dam wall surface is sufficiently heated not only in the downward direction but also in the upward direction, thereby preventing the formation of a shell on the refractory surface as described in item (1) above.

Next, the flow directly downstream is constricted by the central narrow opening 22 shown in Fig. 3 and flows directly downward, so this flow 33 collides with the narrow gap at the bottom of the fan-shaped pool, resulting in the above (2). Since the long side shell described in Section 1 is not remelted, and the openings 22 are uniformly opened in the shape of slits, a uniform effect is exerted over the entire width direction. Therefore, even if the shell is melted by the jet flow 33, the amount is small and acts uniformly over the entire width direction, so that uneven shell thickness distribution will not occur.

Moreover, if such a direct downstream 33 is created, a secondary flow that descends along this flow will be generated. Therefore, as shown in Fig. 3, a flow 32 that collides with the refractory 5 surface and rises flows on the hot water surface toward the nozzle, but this is sucked into the descending secondary flow, as shown in Fig. 3. Since the flow becomes 34, there is no stagnation of the hot water surface near the nozzle 2o.That is, the condition (3) above is satisfied.

Next, in the pouring nozzle 20, the outlet shape of the spout is made into a dogbone shape, and the outlets of the openings 21 and 22 are arranged on almost the same plane, so that the tip of the nozzle has a wide angle and a flat shape as described above. It can be formed into a shape. This makes it possible to reduce the immersion depth of the nozzle. That is, the depth of the fan-shaped molten metal pool can be made shallow, and the residence time of the molten metal in the molten metal pool can be shortened. Therefore, overcooling of the molten metal in the fan-shaped pool can be prevented, and defective shell formation can be eliminated. That is, the condition (4) above is satisfied.

In addition, in conjunction with this flat nozzle shape, in this embodiment, the round flow path 23 at the top of the nozzle is reduced in diameter into a conical shape near the ejection hole, and a dogbone-shaped opening is formed in this flow path 24. are connected. This configuration is also advantageous in terms of nozzle manufacturing.

That is, as a core when making a nozzle by pressing or casting, a round bar having a conical shape at the lower end corresponding to the conical channel 24 in FIG.
A core having a shape corresponding to No. 22 may be prepared. Since these can be removed after the nozzle is formed, the nozzle can be manufactured easily. Note that the lower cone 24 does not necessarily have to be a perfect cone, but may have a reduced diameter shape with a cross-sectional area that decreases from the top toward the bottom.

Another embodiment of the invention will be described with reference to FIGS. 4 and 5. This embodiment is an example in which the present invention is applied to a twin-drum continuous casting machine.

In the twin-drum continuous casting machine, the long sides of the slab are shaped by a pair of drums 40, and the short sides of the slab are shaped by side dam refractories 4↓ for preventing lateral leakage of molten metal.

The same pouring nozzle 2o as shown in FIG. 1 is used.

The flow of the molten metal through the pouring nozzle 20, as shown in FIG. 5, is similar to that shown in FIG. 1 described above in the first embodiment.

As described above, one of the characteristics of the pouring nozzle of this embodiment is that the jet flow flowing down in an inclined manner from the side opening of the jet hole collides with the side dam refractory to heat it. Therefore, as a result of repeated casting experiments, the inventor of the present invention repeatedly conducted various casting experiments to determine the appropriate position where the center of the inclined flow from the side openings collides with the refractory, and as a result, the following results were found.

That is, as shown in Fig. 5, from the melt surface to the narrowest gap R-R line of the fan-shaped molten metal pool (for the twin drums in Fig. 4, the line connecting the centers of the two drums, and the line connecting the centers of the two drums in Fig. 1). If the height from the point where the curved shape changes to a straight line is H, then the collision position of the inclined flow is at a distance of 0.2H to 0.9H from the hot water surface.

If the inclined flow impinges on the refractory too close to the R-R line below 0.98, it will partially remelt the solidified shell in the narrow gap, causing cracks in the slab and 0.98. If it collides with the refractory at a position close to the molten metal surface above 2H, the molten metal surface will ripple violently, causing large wrinkles on the surface of the slab. When the inclined flow collided with the refractory at a distance of 0°2 to 0.9H, the effect of heating the refractory could be obtained without causing these problems.

Furthermore, although the case where the pouring device of the present invention is applied to a constriction-type continuous casting machine has been described above, the molten metal supplied from the nozzle has the effect of flowing evenly throughout the mold, so it is usually There is no particular problem in using it in a continuous casting machine.

〔Effect of the invention〕

According to the present invention, since the outlet shape of the molten metal spouting hole of the pouring nozzle is made into a dogbone shape, it is possible to create a strong lateral inclined flow and a uniform weak downward flow directly below, and a strong lateral inclined flow. By heating the side dam refractories with molten metal, shell formation can be prevented.

In addition, the uniform weak downward flow reduces the possibility of violently hitting the lower part of the fan-shaped pool and re-melting the shell, and even if it re-melts, it exerts a uniform effect on the shell in the narrow gap, so the shell It is possible to cast high-quality slabs without any cracks without making the thickness uneven. Further, the downward flow causes a downward flow near the nozzle at the surface of the melt as a secondary flow, so that the molten metal does not stay there and shell formation at the nozzle can be prevented.

In addition, since the side and lower aperture outlets of the pouring nozzle are arranged on almost the same plane, the lower part of the pouring nozzle that is immersed in the molten metal has a flat and narrow flow path, thereby creating a fan-shaped molten metal pool. The depth can be made shallow, and the residence time of the molten metal in the molten metal pool can be shortened. Therefore, overcooling of the molten metal in the fan-shaped pool can be prevented, and defective shell formation can be eliminated.

If the diameter of the round channel at the top of the nozzle is reduced to a conical shape near the ejection hole and the dogbone-shaped opening is connected to this, it is possible to smoothly flatten the immersed part of the nozzle. At the same time, when the nozzle is manufactured by pressing or casting, the shape of the core can be simplified, and the nozzle can be manufactured easily.

[Brief explanation of drawings]

FIG. 1 is a sectional view along the long side direction of a slab of a continuous casting machine equipped with a pouring device according to an embodiment of the present invention, and FIG. 2 is a sectional view along the short side direction of a slab of the same continuous casting machine. 3 is a sectional view taken along the first line ■-■, and FIG. 4 is a sectional view of a continuous casting machine equipped with a pouring device according to another embodiment of the present invention. FIG. 5 is a sectional view taken along the side direction, and FIG. 5 is a sectional view taken along the long side direction of the slab of the same continuous casting machine. Explanation of symbols 2...Side dam (short side mold) 20...Pouring nozzle 2...Side opening portion 22
...Lower opening 23...Round channel 24...
・Conical flow path 30... Inclined flow 33... Downward flow

Claims (5)

[Claims] (1) A pouring device for a continuous casting machine that manufactures plate materials by continuously cooling and solidifying molten metal, which has a pouring nozzle and directs the spouting hole toward a pair of side molds that are inclined toward the short side mold. The outlet shape of the ejection hole is composed of an aperture and a lower aperture that is continuous with the aperture and faces directly below the nozzle. 1. A pouring device for a continuous casting machine, characterized in that the pouring device has a dogbone shape when viewed from a flat surface, and the outlets of the side openings and the bottom openings are arranged on substantially the same plane. (2) The upper part of the pouring nozzle is shaped to have a round channel, and the lower part immersed in the molten metal is shaped to have a flat and narrow channel. Continuous casting machine pouring device. (3) Continuous casting according to claim 1, characterized in that the diameter of the round channel in the upper part of the nozzle is reduced to a conical shape near the ejection hole, and the dogbone-shaped opening is connected to this. Machine pouring device. (4) A narrowing type continuous casting machine characterized by being equipped with the pouring device according to claim 1. (5) The side aperture is such that the center of the jet flowing down from the side aperture in an inclined manner collides with the side refractory at a point from the molten metal surface to the narrowest part of the fan-shaped molten metal pool. 5. The narrowing type continuous casting machine according to claim 4, wherein the continuous casting machine is configured to have a distance of 0.2H to 0.9H from the molten metal surface, where H is the distance.