JPH0378170B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a continuous casting apparatus for steel sheets having cooling rolls rotating in parallel.

[Prior Art] In general, continuous casting devices include those that continuously cast molten metal into a fixed mold and continuously draw out the solidified ingot, and those that continuously inject molten metal into a moving mold. There is one in which the solidified ingot is continuously sent out by moving the mold. The former is mainly used to produce slabs, and the latter is used to produce thin steel sheets.

In the case of casting slabs, a rolling process is added afterwards and the casting process is expanded significantly, so the casting speed is not required as high. However, in the case of casting steel plates, the cast steel plate becomes the product as it is, so productivity can be improved. In order to increase the casting speed, it is necessary to increase the casting speed.
In order to increase this casting speed, a moving mold, typically a roll type, is used as a continuous steel plate casting apparatus.

As shown in FIG. 2, this type of conventional roll casting device consists of two cooling rolls 1 which are arranged parallel to each other and rotatable in the horizontal direction, with appropriate distance between them.
and a refractory frame 3 serving as a hot water inlet for storing molten metal 2 on the cooling roll 1 and continuously supplying the molten metal 2 between the rolls 1. The lower end of the frame 3 is formed along the curved surface of the cooling roll 1 so as to reduce leakage of molten metal, and the distance 4 between it and the opposing part of the roll 1 is a small distance.

The molten metal 2 poured from the frame 3 is cooled and solidified by contacting the cooling roll 1, and a solidified layer 5 is formed on the surface of the cooling roll 1. This solidified layer 5
The steel plate 6 is extruded by the rotation of the roll 1.

[Problems to be Solved by the Invention] By the way, in the conventional roll casting apparatus described above, as shown in FIG. There was a problem in that the solidified shells 12 formed and grown on the solidified layer 3a were connected, resulting in streak-like scratches or plate breaks 13 on the surface of the solidified layer 5.

In other words, since the frame body 3 stores high-temperature molten metal, the temperature is high as a whole, but the lower end portion 3
Since part a is close to the cooling roll 1, it is cooled from the opposite surface (arrow A in the figure) and radiates heat from the outer surface (arrow B), making the temperature significantly lower than other parts. There is a tendency. Therefore, a solidified shell 12 is formed on the inner surface of the lower end portion 3a of the frame body by the cooling roll 1.
It forms gradually from the side and grows larger over time. The solidified shell 12 formed on the lower end 3a reaches the gap 4 between the cooling roll 1 and is finally connected and fixed to the solidified layer 5 formed on the surface of the cooling roll.

As a result, a large shearing force is applied to this connected and fixed portion due to the rotation of the cooling roll 1, and cracks are formed in the solidified layer 5. This crack remains as a streaky scratch on the surface or causes the plate to break. In addition, if the solidified shell 12 grows quickly and the fixing force of the connecting fixing part is strong, the frame 3 itself may
A large shearing force is applied through the coagulation layer 5 due to the rotation of the cooling roll 1, and the tip 3a of the frame 3 may be damaged and ripped off, resulting in a defective portion D. In such a case, a serious situation arises in which the operation has no choice but to be stopped.

Furthermore, in rare cases, the solidified layer 5 on the surface of the roll 1 may grow rapidly and become thicker, resulting in connection sticking that rises from the roll 1 side to the frame 3 side, which also causes damage to the steel plate. , which may cause board breakage, etc.

In view of the above-mentioned circumstances, the present invention provides a continuous casting apparatus for steel sheets that can prevent the growth of solidified shells between the lower end of the frame and the cooling roll, thereby preventing the occurrence of scratches on the surface of the steel sheet. It was created to do so.

[Means for Solving the Problems] The present invention provides a continuous casting apparatus for steel sheets that has cooling rolls that are appropriately spaced apart and rotate in parallel to each other, and a frame for causing molten metal to flow down between the cooling rolls. A guide body is provided to divert the molten metal into the body, and an inclined surface portion is formed on the upper part of the guide body to guide the molten metal to the boundary between the lower end of the frame and the surface of the cooling roll.

[Function] With the above configuration, the cooling roll is supplied with molten metal from the frame and casts a steel plate by its rotation. The guide member diverts the molten metal along the inclined surface portion, thereby guiding the molten metal flow at a predetermined speed between the lower end of the frame and the cooling roll, thereby preventing the solidified shell from growing.

[Embodiments] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a continuous casting apparatus for steel sheets according to the present invention. Structures similar to those of the conventional apparatus are denoted by the same reference numerals, and their explanations will be omitted.

This casting apparatus is constructed of cooling rolls 1 that are appropriately spaced apart and rotate in parallel to each other as in the conventional case, and a frame 3 for causing molten metal 2 to flow down between the cooling rolls 1. A guide body 20 for diverting the molten metal 2 is provided inside, and
The molten metal 2 is placed on the upper part of the guide body 20 between the lower end 3a of the frame 3 and the surface of the cooling roll 1.
An inclined surface portion 21 is formed that leads to.

The guide body 20 is made of the same refractory material as the frame body 3, and is located above the middle of the two cooling rolls 1.
It extends parallel to the rotational axis of the roll 1. The inclined surface portions 21 are formed symmetrically so as to face the inner surfaces of both side walls of the frame body 3 along the axial direction of the cooling roll 1, and are inclined so that the angle of the top portion 22 thereof is about 60 degrees. In other words, the cross section of the guide body 20 has a substantially equilateral triangle shape, and a diaphragm is substantially formed up to its base (near the boundary 4).

In this embodiment, the top 22 is located at the hot water level 2.
It is formed to protrude more than 3. If the static pressure of the molten metal (steel) is large, the cooling roll 1
There is a background that there is a demand for raising the molten metal level 23 because the degree of adhesion to the steel plate becomes higher and the surface of the steel plate to be cast becomes more beautiful. In this case, there is a risk that a sufficiently high flow rate may not necessarily be obtained by guiding only the bath.

Next, the operation of this embodiment will be explained.

The cooling rolls 1 are rotated in opposite directions by a motor (not shown), and molten metal is supplied to the frame 3. The cooling roll 1 is constantly cooled by cooling water flowing through cooling grooves (not shown) provided therein, and the molten metal 2 supplied to the frame 3
is solidified upon contact with the cooling roll 1, and a solidified layer 5 is formed on the surface of the cooling roll 1. cooling roll 1
The cooling rate is fast, and the solidified layer 5 grows in a short time, and the steel plate 6 is rolled slightly between the rolls 1 and continuously cast.

The molten metal 2 is divided into both sides at the top 22 of the guide 20 and flows down along the inclined surface 21. The flow of the molten metal 2 is narrowed and accelerated toward the gap 4 between the lower end 3a of the frame body and the surface of the cooling roll 1 facing this, and collides with force near the gap 4. As a result, the solidified shell 12 that was being formed on the lower end 3a of the frame is rapidly melted by being heated continuously and in a large amount by this high-speed flow, and its growth is inhibited.

In this way, since the guide body 20 that diverts the molten metal 2 is provided inside the frame 3, the molten metal 2 injected from the frame 3 can be guided toward the lower end 3a of the frame 3. Growth of the solidified shell 12 can be prevented. In particular, by forming the inclined surface portion 21 on the guide body 20,
The molten metal 2 can be reliably guided to the gap 4 without stagnation, the static pressure of the molten metal 2 can be effectively utilized, and a sufficient flow rate can be obtained.

That is, it is possible to prevent streak-like scratches on the surface of the steel plate 6, occurrence of plate breaks, or damage to the frame body 3 due to the solidified shell 12, contributing to the casting of beautiful steel plates. Also, sticking due to solidified shells formed rising from the roll 1 side can be prevented in the same way.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects are achieved.

A guide body for diverting the molten metal is provided inside the frame for flowing the molten metal between the cooling rolls, and an inclined surface part is formed on the upper part of the guide body to guide the molten metal to the boundary between the lower end of the frame and the surface of the cooling roll. By reliably guiding the molten metal between the lower end of the frame and the cooling roll at a considerable flow rate without stagnation, the growth of solidified shells is inhibited and the occurrence of streak-like scratches on the surface of the steel plate is prevented. be able to.

[Brief explanation of drawings]

FIG. 1 is a front sectional view showing an embodiment of a continuous steel plate casting apparatus according to the present invention, FIG. 2 is a front sectional view showing a roll type continuous casting apparatus which is a conventional steel plate continuous casting apparatus, and FIG. The figure is a partially enlarged view for explaining the problem. In the figure, 1 is a cooling roll, 2 is a molten metal, 3 is a frame body, 4 is a gap (boundary), 20 is a guide body, and 21 is an inclined surface portion.

Claims (1)

[Claims] 1. In a continuous steel plate casting apparatus having cooling rolls that are appropriately spaced and rotate in parallel to each other and a frame body for causing the molten metal to flow down between the cooling rolls, a guide body for diverting the molten metal is provided in the frame body. ,
A continuous casting apparatus for steel sheets, characterized in that an inclined surface part is formed on the upper part of the guide body to guide the molten metal to the boundary between the lower end of the frame body and the surface of the cooling roll.