JPH06320232A - Method for continuously casting complex metal material - Google Patents

Abstract

(57) [Summary] [Purpose] When continuously casting a composite metal material, to completely consume the surface molten metal and prevent a decrease in productivity in the case of continuous casting of two or more strands. [Constitution] Inner layer molten metal 2 stored in the inner layer ladle 1a
a is poured into the inner layer tundish 3a, and the outer layer metal 2b stored in the outer layer ladle 1b is poured into the outer layer tundish 3b, and the inner layer metal 2a in the inner layer tundish 3a and the surface layer tundish are poured. The surface metal 2b in the dish 3b is poured into the mold 7a for multi-layer casting at different positions in the vertical direction to cast a composite metal material composed of the surface 8b and the inner layer 8a, and the surface tundish 3b is used. By injecting the metal 2b into the single layer casting mold 7b as well, the single layer metal material is cast in parallel with the casting of the composite metal material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuously producing a composite metal material having different compositions of a surface layer portion and an inner layer portion from a liquid metal, and more particularly to a continuous casting method for continuously casting two strands or more. Is.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a composite metal material by continuous casting, for example, Japanese Patent Publication No. 3-20295.
In the gazette, a static magnetic field band is formed at a predetermined position below the level of the molten metal in the mold so that magnetic field lines extend in a direction perpendicular to the casting direction. There is disclosed a method of injecting the above metal melt with a plurality of nozzles. According to the continuous casting method described in the publication, the flow of the molten metal in the molten metal pool is damped in the static magnetic field portion, and the mixing of the upper and lower layers in the position where the upper and lower layers of the dissimilar metals contact each other is minimized. , Said that a composite metal material with a clear boundary between the surface layer and the inner layer will be manufactured.

[0003]

However, the continuous casting method described in the above publication considers only continuous casting of only one strand, and the continuous casting method described in the publication is converted into continuous casting of two or more strands. In case of applying it, there were the following inconveniences.

Considering the case of casting a composite steel material by continuous casting of two kinds of metals by the "2 ladle-2 tundish method", it can be cast only by a one-strand mold. Therefore, in the case of continuous casting of two or more strands, the other strands are stopped and the productivity deteriorates. Furthermore, when casting a composite steel material with one strand, the injection amount of the surface side molten metal is about 20% of the total injection amount (composite steel material with a surface layer thickness of 10% on each side), and the consumption of the molten metal in the surface ladle is small. Since the casting cannot be completed due to time restrictions, the residual molten metal in the ladle for the surface layer is treated by turning it back into the converter or injecting scrap. Therefore, there is a problem that the yield is very low, the productivity of continuous casting is low, and the manufacturing cost is very high.

Therefore, an object of the present invention is to prevent the deterioration of productivity in the continuous casting of two or more strands by completely consuming the surface molten metal in the continuous casting of the composite metal material.

[0006]

In order to achieve the above-mentioned object, the method for continuously casting a composite metal material according to the present invention is to inject the metal for the inner layer, which is stored in the ladle for the inner layer, into the tundish for the inner layer, and at the same time, to form the outer layer. The outer layer metal stored in the ladle is poured into the outer layer tundish, the inner layer metal in the inner layer tundish and the surface layer metal in the surface tundish in the mold for multi-layer casting. Casting a composite metal material by injecting the composite metal material consisting of the surface layer and the inner layer into the upper and lower positions respectively and by injecting the surface metal from the surface tundish into the mold for single layer casting as well. A single-layer metal material is cast in parallel with the above.

[0007] The casting time of the composite metal material of the metal for the inner layer and the metal for the outer layer, which is injected into the casting mold for multi-layer casting, is determined in advance, and the metal of the least amount of metal is secured to remove the surplus metal. It is desirable to perform single-layer casting in another mold and control the pouring amount so that the casting time is shorter than or substantially equal to the multi-layer casting time.

[0008]

[Function] The metal for the inner layer in the tundish for the inner layer and the metal for the surface layer in the tundish for the surface layer are respectively injected at different positions in the upper and lower parts of the mold for multi-layer casting, and a composite metal material composed of the surface layer and the inner layer is cast. To be done. At the same time, the surface layer metal in the surface layer tundish is also injected into a single layer casting mold provided separately from the multilayer casting mold.
As a result, the consumption of the surface layer metal in the surface layer tundish per unit time becomes large, and the inner layer metal in the inner layer tundish and the surface layer metal in the surface layer tundish are completely consumed at the same time.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of an apparatus for carrying out the present invention. In FIG. 1, 1a is an inner layer ladle, 1
b is a ladle for the surface layer, the molten metal 2a for the inner layer is stored in the ladle 1a for the inner layer, and the molten metal 2 for the surface layer is stored in the ladle 1b for the surface layer.
b is stored. An inner layer ladle long nozzle 4a for supplying the inner layer molten metal 2a to the inner layer tundish 3a is provided on the bottom surface of the inner layer ladle 1a, and a surface layer molten metal 2b is provided on the bottom surface of the surface layer ladle 1b. A long ladle nozzle 4b for the surface layer which is supplied to the dish 3b is connected.

At the end of the bottom of the inner layer tundish 3a on the surface layer tundish 3b side, there is an inner layer immersion nozzle 6a in which the pouring amount of the inner layer molten metal 2a is controlled by the vertical movement of the inner layer tundish stopper 5a. It is connected. Further, at the end of the bottom of the surface layer tundish 3b on the side of the inner layer tundish 3a, the amount of the surface layer molten metal 2b injected is controlled by the vertical movement of the surface layer tundish stopper 5b-1. -1 is connected, and at the end opposite to the inner layer tundish 3a,
Similarly, a submerged nozzle 6b-2 for the surface layer is connected in which the injection amount of the molten metal 2b for the surface layer is controlled by the vertical movement of the tundish stopper 5b-2 for the surface layer.

The inner layer immersion nozzle 6a from the inner layer tundish 3a and the surface layer immersion nozzle 6b-1 from the surface layer tundish 3b have different lengths. It extends vertically. Further, a static magnetic field generator 9 for forming a static magnetic field band is provided at a position lower than the molten metal level on the outer periphery of the mold 7a by a predetermined distance so that the magnetic field lines extend in a direction perpendicular to the casting direction.

Further, the surface layer immersion nozzle 6b-2 provided at the end of the surface layer tundish 3b opposite to the inner layer tundish 3a extends vertically toward the inside of the single layer casting mold 7b. It is delayed.

Next, the operation of the above-mentioned device will be described.

When each of the stoppers 5a, 5b-1 and 5b-2 is pulled up, the molten metal 2a for the inner layer in the tundish 3a for the inner layer is supplied below the mold 7a through the long immersion nozzle 6a for the inner layer, and , Tundish for surface 3
The surface molten metal 2b in b is a short surface immersion nozzle 6b-
It is supplied to the upper side of the mold 7a via 1.

The surface layer molten metal 2b supplied through the surface layer immersion nozzle 6b-1 comes into contact with the mold 7a to be cooled and solidified to form a surface layer 8b. Also, the inner layer immersion nozzle 6
The inner layer molten metal 2a supplied through a contacts with the inner surface of the surface layer 8b and is cooled and solidified to form the inner layer 8a. At this time, the flow of the molten metal is damped by the static magnetic field from the electromagnetic field generating device 9 provided at substantially the same height as the boundary surface of the dissimilar metals, and the mixing of the surface layer molten metal 2b and the inner layer molten metal 2a is suppressed. Therefore, the composite steel material in which the surface layer and the inner layer are clearly separated is cast from the mold 7a.

Further, the surface layer melt 2b supplied through the immersion nozzle 6b-2 comes into contact with the mold 7b to be cooled and solidified to form a solidified layer 8c. Therefore, the single layer steel material made of a single metal is cast from the mold 7b.

Next, the consumption amount of the inner layer molten metal 2a and the surface layer molten metal 2b in the above-mentioned casting apparatus per unit time will be examined. When casting the composite steel material in the multi-layer casting mold 7a, most of the composite steel material is occupied by the inner layer melt 2a, and the surface layer melt 2b only forms the surface layer of the composite steel material. The consumption of the surface layer molten metal 2b is smaller than the consumption amount, and for example, the consumption amount of the surface layer molten metal 2b is only about 20% of the injection amount into the mold 7a.
Therefore, when the inner layer ladle 1a and the surface layer ladle 1b have the same capacity, when considering only the mold 7a, the inner layer molten metal 2a in the inner layer ladle 1a is consumed first, and the inner layer molten metal 1a is consumed. Even when the 2a is lost, a considerable amount of the surface molten metal 2b remains in the surface ladle 1b.

However, in the present invention, the molten metal 2b for the surface layer is supplied to the mold 7a to cast a single layer steel material which consumes a large amount. Therefore, by selecting the size or casting speed of the single layer steel material, the inner layer It is possible to make the consumptions of the molten metal 2a for the surface and the molten metal 2b for the surface layer per unit time the same. Therefore, the consumption of the inner layer molten metal 2a in the inner layer ladle 1a and the surface layer molten metal 2b in the surface layer ladle 1b are completed at the same time,
A large amount of the surface layer molten metal 2b does not remain in the surface layer ladle 1b.

[0019]

As described above, according to the present invention,
Consuming less molten metal per unit time compared to the molten metal for the inner layer, the single layer steel material is cast in parallel with the casting of the composite steel material by using the molten metal for the surface layer. By making the amounts substantially equal, the molten metal in the inner ladle and the molten metal in the surface ladle can be completely consumed at the same time. As a result, it is not necessary to return the molten metal for the surface layer remaining in the ladle for the surface layer to the converter for reuse, or to perform the residual molten steel treatment such as heating, thereby improving the productivity of continuous casting. In addition, it is possible to prevent the quality from changing and the yield from decreasing due to the interruption of the work.

[Brief description of drawings]

1 is a diagram showing an example of an apparatus for carrying out the present invention.

[Explanation of symbols]

 1a Inner layer ladle 1b Surface layer ladle 2a Inner layer melt 2b Surface layer melt 3a Inner layer tundish 3b Surface layer tundish 4a Inner layer ladle long nozzle 4b Surface layer ladle long nozzle 5a Inner layer tundish stopper 5b- 1, 5b-2 Surface layer tundish stopper 6a Inner layer immersion nozzle 6b-1, 6b-2 Surface layer immersion nozzle 7a, 7b Mold 8a Inner layer 8b Surface layer 8c Solidification layer 9 Static magnetic field generator

Claims (2)

[Claims] 1. The inner layer metal stored in the inner layer ladle is injected into the inner layer tundish, and the outer layer metal stored in the outer layer ladle is injected into the outer layer tundish to form the inner layer tundish. Inner layer metal in the tundish and surface layer metal in the surface layer tundish are respectively injected at different positions vertically in the mold for multi-layer casting to cast a composite metal material consisting of the surface layer and the inner layer and the surface layer. Continuous casting method for composite metal material, characterized in that the single-layer metal material is cast in parallel with the casting of the composite metal material by injecting the metal for the surface layer from the tundish into the mold for the single-layer casting. . 2. A casting time of a composite metal material of a metal having a minimum amount of an inner layer metal and an outer layer metal, which is injected into the multi-layer casting mold, is obtained in advance to secure the metal having the least amount of metal. The continuous casting method for a composite metal material according to claim 1, wherein the metal is cast in a single layer in another mold, and the pouring amount is controlled so as to be earlier than or substantially equal to the multi-layer casting time.