JPH0698467B2 - Pouring device for continuous casting machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pouring device for a continuous casting machine, and in particular, a twin-belt continuous casting machine or a twin-drum continuous casting machine having a fan-shaped molten metal pool. The present invention relates to a pouring device suitable for a continuous casting machine that performs casting with a mold of a method.

[Conventional technology]

In a continuous casting machine such as a twin-belt continuous casting machine or a twin-drum continuous casting machine that has a fan-shaped molten metal pool, a short dam called a side dam that molds the short side of the slab is used in continuous casting machines that perform casting with a narrowing type mold. When a solidified shell is formed in the side mold, it causes breakout and deteriorates the quality of the short side surface of the slab, and therefore, the utmost efforts are made to prevent the shell from being formed in the side dam. Various methods have been proposed for preventing the shell from being formed on the side dam, such as embedding a heater in a refractory and heating. However, the most economical method is disclosed in JP-A-62-2
As described in Japanese Patent Publication No. 96944, it is a method of applying a molten metal jet from a pouring nozzle to a side dam to heat it. That is, in the publication, in addition to the opening of the narrow gap for supplying the molten metal to the central portion of the molten metal pool, inclined openings are provided on both sides of the hole, and the side dam is heated by the molten metal poured,
The shell is not formed on the side dam surface.

[Problems to be Solved by the Invention]

In a narrowing twin belt continuous casting machine or 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 in proportion to almost 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 be too cold. Thus, if the molten metal is too cold, shells are likely to be generated on the surface of the fan-shaped refractory material or around the nozzle, which causes casting trouble.

In addition, the large depth of the fan-shaped pool also lengthens the length of the fan-shaped refractory, which makes it difficult to uniformly eject the impingement flow on the surface of the fan-shaped refractory by the lateral inclined flow.

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

On the other hand, in the nozzle of Japanese Patent Laid-Open No. 62-296944, lateral and downward flow openings are provided up and down, which is disadvantageous in reducing the depth of the fan-shaped pool as described above. is there.

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

[Means for Solving the Problems]

In order to achieve the above object, the present invention, in a pouring device of a continuous casting machine for continuously cooling and solidifying a molten metal to produce a plate material, has a pouring nozzle, and its ejection hole is directed toward the short side mold. Composed of a pair of lateral openings that are inclined toward each other and a downward opening that is continuous with the downward openings and that faces the direction directly below the nozzle, and the lateral openings and the downward openings are combined into a jet. The outlet shape of the hole is formed in a dogbone shape when viewed in a developed shape with respect to the plane orthogonal to the nozzle, and the outlets of the side opening portion and the lower opening portion are arranged on substantially the same plane.

Preferably, the upper portion of the pouring nozzle is shaped to have a round channel, and the lower portion immersed in the molten metal is shaped to have a flat narrow channel.

Further, preferably, the diameter of the round passage in the upper part of the nozzle is reduced to a conical shape in the vicinity of the ejection hole, and the dogbone-shaped opening portion is connected to this.

The present invention further provides a refining type continuous casting machine comprising the above pouring device.

In this case, preferably, in the lateral opening, the position where the center of the jet flow that flows downward from the lateral opening collides with the lateral refractory is the narrowest part of the fan-shaped molten metal pool from the molten metal surface. When the distance to H is H, the distance is 0.2H to 0.9H from the molten metal surface.

[Action]

The outlet shape of the injection hole of the pouring nozzle of the present application has a dogbone shape, and therefore the flow of molten metal is as follows.

That is, since the side opening is an opening inclined to the side dam direction, the jet flow can be made to flow in an inclined shape, and the flow can be applied to a portion of the side dam at a desired height position. Then, from the point of collision with the side dam, the jet flow is divided into upper and lower parts and flows along the wall surface of the side dam.
Since the molten metal pool in the narrowing mold is fan-shaped and the lower part is narrow, the flow rate to the lower part is limited, 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.

And, since the outlet shape of the ejection hole is a dogbone shape, the lower opening portion is a narrow slit-shaped opening,
Since the passage is narrowed, the flow rate in the direction directly below the nozzle is limited, resulting in a weak flow. Therefore, this is prevented from flowing down and hitting the lower narrow gap portion of the fan-shaped pool at a strong flow rate, which reduces the trouble of re-melting the shell. Further, since the slit-shaped openings of the lower openings are connected to the side openings, the downward flow becomes a weak jet that is uniform over the entire plate width direction of the narrowed narrow gap. Therefore, even if the shell is most melted by the jet flow, the amount thereof is small, the shell acts uniformly over the entire width direction, and an uneven shell thickness distribution does not occur.

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

In addition, by arranging the dogbone-shaped ejection holes of the pouring nozzle on approximately the same plane, the lower part of the pouring nozzle immersed in the molten metal has a flat narrowed 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, it is possible to prevent the molten metal in the fan-shaped pool from being overcooled, and to prevent defective shell formation.

In the case of manufacturing a nozzle by pressing or casting, the circular flow path at the upper part of the nozzle is conically reduced in the vicinity of the ejection hole, and the side and lower openings of the dogbone shape are connected to this. The shape of the core can be simplified and the nozzle can be easily manufactured.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. The present embodiment is an example in which the present invention is applied to a narrow-down twin-belt continuous casting machine described in JP-A-59-199151.

1 to 3, the twin-belt continuous casting machine has a pair of belts 1 for molding the long side of the slab and a pair of side dams 2 for molding the short side of the slab. In the drawing continuous casting machine, the pair of belts 1 are wound around the guide rollers 3 and guided so that the pouring portion has a fan shape, and the 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 cannot be pulled out in the downward direction when the shell is formed by the fan-shaped pool 4 part, and therefore this part is composed of the heat insulating refractory material 5. To be done. The lower part is formed of a copper member mold 6 so that the short side shell is cooled and shaped after changing from the curved shape to the parallel part. This copper member mold 6 is filled with cooling water A
To B for cooling.

In the fan-shaped pool 4 formed by the pair of belts 1 and the side dams 2, as shown in FIG. 2, the molten metal 8 from the tundish 7 passes through the opening nozzle 9, and the amount of the molten metal is transferred by the sliding valve 10. It is adjusted and poured. Sliding valve
Reference numeral 10 is composed of two fixed plates 11 and 12 and a plate 14 which moves in the two plates by a cylinder 13. These plates are then fastened with the cover 15. The molten metal adjusted by the sliding valve 10 then flows down through the pouring nozzle 20 of this embodiment and is poured into the fan-shaped pool 4.

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

Further, the pouring nozzle 20 of the present embodiment has an ejection hole composed of a pair of lateral openings 21 inclined to the direction of the refractory 5 and a lower opening 22 continuous with the lateral openings 21 and directed directly below the nozzle. As shown in FIG. 3, the outlet shape of the ejection holes, which is a combination of these openings, has a dog-bone shape when viewed in a developed shape with respect to the plane orthogonal to the nozzle, and each of the openings 21, 22 The outlets of are located on approximately the same plane.

Further, the upper portion of the pouring nozzle 20 has a round flow path with a diameter φD.
Although it has 23, the diameter of the spout hole to be immersed in the molten metal is reduced to a conical flow path 24 to a diameter φd, and the dogbone-shaped openings 21, 22 are connected thereto. Further, the nozzle shape of this portion is also formed in a flat shape in accordance with the shapes of the flow path 24 and the open rear portions 21 and 22.

The structure of the pouring nozzle 20 as described above is obtained as a result of the inventors of the present application repeating various casting experiments and making further studies. That is, the inventor of the present application has found out that the preferable conditions for the pouring device are as follows in the narrow casting in which the shape is changed from the fan-shaped pool to the parallel shape as described above.

(1) The refractory material can be sufficiently heated by the jet flow of the pouring nozzle 20 so that a solidified shell is not formed on the adiabatic refractory material 5 in the fan-shaped pool 4 portion shown in FIG.

(2) The downward flow from the pouring nozzle does not collide with the lower narrow gap portion of the fan-shaped molten metal pool 4 to remelt the long side shell,
Also, exert a uniform action over the entire width direction.

(3) A stagnation occurs on the molten metal surface of the fan-shaped molten metal pool 4, and a shell is not formed. This is especially formed around the nozzle 20 and is easy to grow.

(4) When the amount of the molten metal in the fan-shaped pool 4 is large, the molten metal poured from the nozzle 20 stays for a long time there, and it is unnecessary, that is, the side dam refractory 5 described in (1).
Alternatively, the shell is easily modeled on the molten metal surface or the like described in the item (3). Therefore, the nozzle shape should be as shallow as possible.

The pouring nozzle 20 satisfies all the above conditions.

That is, in the pouring nozzle 20 of the present embodiment, since the opening diameter of the side opening portion 21 of the dog bone-shaped ejection opening portion is large and inclined, as shown in FIG. The supplied jet flow becomes a vigorous inclined flow 30 and collides with the surface of the refractory 5 and is separated into a downward flow 31 and an upward flow 32, which flow while heating the wall surface of the refractory. At this time,
Since the molten metal pool 4 is fan-shaped and the lower part is narrow, the downward flow rate is limited, and a sufficient amount of upward flow flows despite the inclined flow. Therefore, the wall surface of the side dam is sufficiently heated not only in the downward direction but also in the upward direction to prevent the shell formation on the refractory surface described in the above item (1).

Next, immediately downstream is narrowed down by the narrow opening 22 at the center shown in FIG. 3 and flows downward, so that this flow 33 collides with the lower narrow space of the fan-shaped pool, resulting in (2) above. It does not redissolve the long-side shell described in the above section, and since the opening portion 22 is uniformly formed in a slit shape, a uniform action is exerted over the entire width direction. Therefore, even if the shell is most melted by the jet flow 33, the amount thereof is small, the shell flows uniformly over the entire width direction, and an uneven shell thickness distribution does not occur.

Further, if such a direct downstream 33 is formed, a secondary flow descending along this flow is generated. Therefore, as shown in FIG. 1, a flow 32 that collides with the refractory 5 surface and rises flows toward the nozzle on the molten metal surface, but this is sucked into the descending secondary flow, as shown in FIG. Since it becomes the flow 34, the molten metal surface near the nozzle 20 does not stay. That is, the condition of the above item (3) is satisfied.

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

In addition to this flat nozzle shape, in the present embodiment, the circular flow path 23 in the upper part of the nozzle is reduced to a conical shape in the vicinity of the ejection hole, and the flow path 24 is opened in a dogbone shape. The holes are connected. This structure is also advantageous in manufacturing the nozzle. That is, as a core for making a nozzle by pressing or casting, a round bar having a conical shape corresponding to the conical passage 24 at the lower end in FIG. It suffices to prepare a core having a shape corresponding to. These can be removed after shaping the nozzle, so that the nozzle can be easily manufactured. The lower cone 24 does not necessarily have to be a perfect cone, and may be of a reduced diameter shape having a cross-sectional area that is smaller from the upper portion toward the lower portion.

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

In a twin-drum continuous casting machine, the long side of the slab is shaped by a pair of drums 40, and the short side of the slab is shaped by a side dam refractory 41 for preventing lateral leakage of molten metal. The same pouring nozzle 20 as that shown in FIG. 1 is used.

As shown in FIG. 5, the flow of molten metal by the pouring nozzle 20 is the same as that shown in FIG. 1 of the first embodiment.

As described above, as one of the features of the pouring nozzle of the present embodiment, it has been described that the jet flow that flows down in an inclined shape from the lateral opening portion of the jet hole collides against the side dam refractory and is heated. Then, as a result of repeating various casting experiments by the inventor of the present invention at an appropriate position where the center of the inclined flow from the side opening collides with the refractory, it was found to be as follows.

That is, as shown in FIG. 5, the narrowest clearance line RR line of the fan-shaped molten metal pool from the molten metal surface (in the twin drum of FIG. 4, a line connecting the centers of two drums, the twin belt of FIG. 1). Then, if the height from the curved shape to the point where it changes linearly) is H, the impingement position of the inclined flow is at a distance of 0.2H to 0.9H from the molten metal surface. When the inclined flow collides with the refractory at a position too close to the RR line below 0.9H, the solidified shell in the narrow gap partly remelts, causing the slab to crack, and Also, when it collides with the refractory at a position near the upper surface of the molten metal, the surface of the molten metal becomes severely wavy, and large wrinkles are generated on the surface of the slab.
When the inclined flow collided with the refractory at a distance of 0.2 to 0.9H, the heating effect of the refractory could be obtained without causing these problems.

Further, in the above, the case where the pouring device of the present invention is applied to a narrow-down type continuous casting machine has been described, but since the molten metal supplied from the nozzle has an effect of flowing uniformly in the entire mold, There is no particular problem in using it in a continuous casting machine.

〔The invention's effect〕

According to the present invention, since the outlet shape of the molten metal ejection hole of the pouring nozzle is formed into a dogbone shape, it is possible to form a strong lateral inclined flow and a uniform weak downward flow in the direct downward direction, and a strong lateral inclination. The flow can heat the side dam refractory with molten metal, and prevent shell formation.

In addition, the uniform weak downward flow reduces the re-melting of the shell by hitting the bottom of the fan-shaped pool violently, and even if it re-melts, it exerts a uniform action on the narrow gap shell. It is possible to cast a slab of good quality without cracking without making the thickness of the slab uneven. Further, the descending flow also causes a descending flow in the vicinity of the nozzle on the molten metal surface as a secondary flow, so that the molten metal does not stay and the shell formation on the nozzle can be prevented.

Further, since the openings of the openings at the side and the bottom of the pouring nozzle are arranged on substantially the same plane, the fan-shaped molten metal pool can be formed by making the lower part immersed in the molten metal have a flat narrowed flow path. The depth can be made shallow, and the residence time of the molten metal in the molten metal pool can be shortened. Therefore, the supercooling of the molten metal in the fan-shaped pool can be prevented, and the defective shell formation can be eliminated.

When the diameter of the round flow path in the upper part of the nozzle is reduced to a conical shape in the vicinity of the ejection hole, and the dog bone-shaped opening is connected to this, it is possible to smoothly flatten the nozzle immersion part. In addition to being possible, it is possible to simplify the shape of the core when manufacturing the nozzle by pressing or casting, and facilitate the manufacturing of the nozzle.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a continuous casting machine equipped with a pouring device according to an embodiment of the present invention taken along the long side direction of the cast piece, and FIG. 2 is taken along the short side direction of the cast piece of the continuous casting machine. FIG. 3 is a sectional view, FIG. 3 is a sectional view taken along line III-III, and FIG. 4 is a short side of a cast piece of a continuous casting machine equipped with a pouring device according to another embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the direction, and FIG. 5 is a cross-sectional view taken along the long-side direction of the slab of the continuous casting machine. Explanation of code 2 …… Side dam (short side mold) 20 …… Pouring nozzle, 21 …… Side opening 22 …… Lower opening, 23 …… Round channel 24 …… Conical shape Flow path, 30 ... Inclined flow 33 ... Downflow

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Saburo Moriwaki 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works

Claims (5)

[Claims] 1. A pouring device of a continuous casting machine for continuously cooling and solidifying a molten metal to produce a plate material, comprising a pouring nozzle,
The ejection hole is composed of a pair of side openings that are inclined toward the short side mold, and a lower opening that is continuous with the side openings and that faces directly below the nozzle, and the side openings. The outlet shape of the ejection hole, which is a combination of the lower opening portion and the lower opening portion, is formed into a dogbone shape when viewed in a developed shape with respect to the plane orthogonal to the nozzle, and the outlets of the side opening portion and the lower opening portion are substantially the same. A pouring device for a continuous casting machine, which is arranged on the surface. 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 narrow channel. The pouring device for the continuous casting machine described. 3. A circular flow path in the upper part of the nozzle is reduced in a cone shape in the vicinity of the ejection hole, and the dogbone-shaped opening is connected to the circular flow path. Pouring equipment for continuous casting machines. 4. A refining type continuous casting machine comprising the pouring device according to claim 1. 5. The lateral opening portion is located at a position where the center of the jet flow flowing downward from the lateral opening portion collides with the lateral refractory from the molten metal surface to the narrowest portion of the fan-shaped molten metal pool. 5. The narrowing-down continuous casting machine according to claim 4, wherein when the distance to H is H, the distance is 0.2H to 0.9H from the molten metal surface.