JPS61108457A - Electromagnetic stirrer in continuous casting installation - Google Patents

Abstract

PURPOSE:To decrease leakage magnetic flux and to reduce the size over the entire part of a coil by connecting the top ends and bottom ends of the conductors in a pair of vertical surface parts adjacent to each other with one corner part as a center to each other in the stage of forming the coil. CONSTITUTION:The coil C consists of four coils. Each of the four coils consists of plural windings along the vertical surface and consists of vertical parts (a), (b) where the conductors array parallel in the transverse direction and parts (c), (d) connecting the vertical parts at the upper and lower parts. The formation of the coil by winding the conductors is executed by connecting the conductors of the vertical surface parts adjacent to each other with one corner part as a center are connected to each other to an L shape and gathering four pieces of such L-shaped parts to form the coil. The current of one phase out of two phases is conducted to the coils 1, 3 and the AC current of another one phase shifted by approximately pi/2 phase is conducted to the coils 2, 4 to generate a rotating magnetic field in the cage-shaped part formed by the four coils to induce and stir the material to be cast.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to continuous casting equipment for bloom.

This invention relates to an electromagnetic stirring device used for stirring molten steel within the walls of a copper mold or molten steel within the shell of a slab drawn from the mold by electromagnetic induction.

(Prior art) In continuous casting equipment for blooming, when horizontal rotational motion is applied by electromagnetic induction to the molten steel in the wall of the mold steel or the molten steel in the shell of the slab drawn from the mold, the surface properties of the slab change due to the floating of inclusions. continuous casting of non-deoxidized steel by raising air bubbles on the surface of the slab.

It has recently become known that it is highly effective in improving the internal quality of slabs by increasing the equiaxed crystal structure of slabs and reducing center segregation, and the fifth The rotating magnetic field type convex pole electromagnetic stirring device shown in the figure (Registered Utility Model No. 1242046) and the rotating magnetic field type rectangular electromagnetic stirring device shown in FIG.
9265) is publicly known.

However, it has been found that continuous casting of undeoxidized steel with a large cross-section bloom requires a relatively large stirring force.

Furthermore, it was found that it was necessary to downsize the device in order to install it inside the mold. In a rotating magnetic field type convex pole type electromagnetic stirrer, when a bloom with a large cross section is targeted, the effective magnetic flux that should go to the opposing magnetic poles is short-circuited to the adjacent magnetic poles, and the opening of leakage magnetic flux increases, which is unsuitable.

Therefore, in the conventional rotating magnetic field square type electromagnetic stirrer, there is a method to achieve high thrust by bringing the effective part that contributes to stirring of one winding closer to the slab to reduce leakage magnetic flux (Japanese Patent Laid-Open No. 56-139265] The structure of one winding becomes extremely complicated.

Furthermore, since each coil is U-shaped, the only way to reduce the gap between the core and the core, thereby reducing leakage magnetic flux and increasing efficiency, is to increase the manufacturing precision of the coil dimensions.

(Problems to be Solved by the Invention) The present invention provides a rotating magnetic field type rectangular structure to increase the effective amount of magnetic flux for the slab being drawn from the mold inner steel wall or the mold copper wall, and an L-shaped electromagnetic By configuring the coil to surround the four corners 'f' and sandwiching the slab, it is possible to reduce the gap between the winding and the core.As a result, leakage magnetic flux is reduced. In addition to increasing the thrust, the entire coil is made smaller and has a structure that is easy to manufacture, thereby improving manufacturing accuracy and reducing manufacturing costs.

(Means for solving the problem 1) The electromagnetic stirring device according to the present invention is driven by two-phase alternating current, and is composed of four coils corresponding to two phases of the electromagnetic coil #'i. The gist of the present invention is that when a conductor is wound to form a coil, a vertical portion in which the conductor is arranged horizontally in parallel along a vertical plane, and an upper end portion and a lower end portion of the vertical portion are fully connected and folded. In an electromagnetic stirring device consisting of a mold-shaped coil bent to form an upper horizontal part and a lower horizontal part, the vertical part forming four vertical planes, the coils are placed next to each other with one corner in between. This is a 12C magnetic stirrer for continuous casting equipment, characterized in that the upper and lower ends of a pair of vertical conductors are connected to each other.

The features of the present invention will be explained below with reference to embodiments shown in the drawings.

FIG. 1 shows a conceptual diagram of a coil of an example of an electromagnetic stirring device according to the present invention, and FIG. 2 shows a sectional view of the coil.

The coil C of the present invention consists of four coils (1 to 4),
As shown in Fig. 1, each of the four coils consists of a plurality of turns along the vertical plane, and has a vertical section a where the conductors are arranged parallel to the willow direction;
b and it at the top and bottom.

Consists of connecting c and d parts. A feature of the present invention is that when winding a conductor to form a coil, conductors on adjacent vertical planes are connected with one corner inside to form an L shape, and these L-shaped parts't-4 By collecting them, the entire mouth-shaped coil is formed. At this time, since two vertical parts are formed on one surface, vertical parts that are adjacent to each other with one corner in between are those that are close together as shown in Figure 1, and those that are close together as shown in Figure 3. There are two paths that are far apart, but either one will work.

By the way, in the conventional method, two corner portions are placed in the center, opposing vertical portions are connected to form a mouth-shaped portion, and the mouth-shaped portions are gathered to form a mouth-shaped coil. but,
In adjusting the gap between the core 6 and the coil 9, the L-type according to the present invention is much more advantageous than the L-type.

The portions a% and d of each of the four coils in the present invention are as follows.

In this embodiment, each conductor is composed of five conductors.

In the coil shown in the figure, there are two phases (U phase) in coils 1 and 3.

Formed by four coils, the current of one phase (U phase) of the V phase is passed through the coils 2 and 4, and the alternating current of the other phase (V phase) with a phase shift of approximately π/2 is passed to the coils 2 and 4. By generating a rotating magnetic field in the cage-shaped part, the object to be cast can be stirred by induction.

The conductor differs depending on the cooling method; in the case of direct cooling by internal water flow, a hollow conductor with a cooling water passage 5 inside is used, and in the case of indirect cooling by immersion cooling, a solid conductor with water-resistant insulated syllables on the outside is used. In the case of a high-current, high-thrust type combined cooling in which direct cooling and indirect cooling are used in combination to fully improve the cooling capacity, a hollow one with water-resistant V& applied on the outside is used.

In this example, when the KUA per pole is all equal.

Compared to the conventional rotating magnetic field square electromagnetic stirrer, it achieves a higher center magnetic flux density, simplifies the coil structure, and simplifies the upper and lower horizontal parts, making it easier to manufacture and maintain the coil. I was able to do that.

(Effects of the Invention) As specifically explained in the examples above, the electromagnetic stirring device in the continuous casting equipment according to the present invention is of the two-phase AC type, and the electromagnetic coil has four coils arranged in one basket shape. In combination, by installing an iron core around the vertical part and between the upper and lower horizontal parts, it is possible to reduce the air gap with respect to the molded copper strip or cast slab. In addition to improving the complexity of coil manufacturing in the conventional technology shown above, since the coil is L-shaped rather than U-shaped, the coil is pressed inside the corner of the core to reduce the gap between it and the core and reduce leakage magnetic flux. can. In addition, the cooling method can be made more convenient and economical by selecting the conventional cooling method depending on the magnitude of the current. Magnetic stirring can be performed.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of a coil of an embodiment of an electromagnetic stirring device according to the present invention. Figure 2 is a cross-sectional view of the same coil. FIG. 3 is a conceptual diagram of a coil according to another embodiment of the present invention. FIG. 4 is a cross-sectional view of the same coil, FIG. 5 is a cross-sectional view of a conventional convex pole type electromagnetic stirring device, and FIG. 6 is a cross-sectional view of a conventional rectangular electromagnetic stirring device. la, 1b, 2a, 2b, 3a, 3b, 4a, 4b
- Coil vertical portion, lc, 2c, 3c, 4c... Coil upper connecting portion, ld, 2d, 3d, 4d... Coil lower connecting portion, 5... Cooling water passage, 6... Core. Agent Patent attorney Masaaki Akizawa Mitsunobu 2 people 71 Figure 7t'2 Figure 3b 4 (1 Figure 3 Valve 4 Figure 1b 4Q Juice 5 Figure

Claims (1)

[Claims] (1) When winding a conductor to form a coil, connect the vertical part where the conductor is parallel to the horizontal direction along the vertical plane, and the upper and lower ends of the vertical part, respectively, and bend them to form the upper part. In an electromagnetic stirring device consisting of a cage-shaped coil, which has a horizontal part and a lower horizontal part, and the vertical part forms four vertical planes, a pair of adjacent cage-like coils with one corner part in the middle are used. An electromagnetic stirring device for continuous casting equipment, characterized in that the upper and lower ends of vertical conductors are connected to each other.