JPH0452171B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention relates to an electromagnetic stirring device that is combined with a guide device installed directly below the mold or in the secondary cooling zone of a continuous casting machine. This invention relates to an electromagnetic stirring device used to guide slabs that leave molten metal so as not to cause breakouts, etc., and to stir the molten metal in order to improve the solidification structure and improve the quality of the slabs. .

BACKGROUND ART In recent years, in the field of continuous casting of steel, etc., a technique of stirring molten metal, such as molten steel, using electromagnetic force has come into widespread use in order to improve the quality of slabs, especially the solidified structure. The purpose of applying this electromagnetic stirring varies depending on the installation location, but for example, when targeting molds, it is mainly used to promote the floating of air bubbles and inclusions by making the molten steel flow, and to prevent pinholes, blowholes, etc. The purpose is to promote the removal of bubble defects and non-metallic inclusions. Moreover, the electromagnetic stirring device installed in the secondary cooling zone under the mold is mainly aimed at increasing the equiaxed crystallinity.

The concept of attaching an electromagnetic stirring device to a continuous casting machine is a technology that has only recently been adopted, and the specific structure of the device has not yet been generalized. Therefore, although the known technology is not clear regarding specific examples installed in conjunction with the guide device section under the mold, which is the object of the present invention,
As an extension of the prior art, a format as shown in FIGS. 1 and 2 has been considered in the case of disposing it directly under the mold.

Such a guide device directly below the mold prevents the slab with a thin solidified shell directly below the mold outlet from breaking out or deforming due to the unsolidified molten steel remaining inside, and reduces friction at the lower end of the mold inner wall. Generally, foot rollers (Fig. 1) are installed in a row or guide plates (Fig. 2) are used.

Figure 1 shows an example of a guide device in which a foot roller 3 is used to support the slab directly below the mold 2, and the back (outside)
This is a type in which a ring-type coil 4 of a rotating magnetic field type is arranged at the top. In the format shown in this example, coil 4
is too far from the slab 1, the magnetic force is greatly attenuated, and the stirring force is reduced. Melting current is generated in the foot roller 3, which tends to cause troubles such as electric contact. Furthermore, the spray cooling on the slab 1 is difficult due to the structure. There are many difficult things to do.

FIG. 2 shows an example of a guide device in which a guide plate 6 for protecting the coil, which also serves as a slab guide, is provided in front of the rotating magnetic field type coil 4. Although this type has the advantage of bringing the coil 4 closer to the slab 1,
Since the guide plate 6 cannot cool the slab 1, there is a risk that the cooling of the slab 1 will be insufficient and abnormal bulging will occur. Furthermore, if the guide plate 6 has a water-cooled structure that can cool the slab, the thickness will increase,
The advantage of being able to bring the coil closer to the slab is lost.

Therefore, the present invention does not have the problems of conventional electromagnetic stirring devices installed under the mold, preferably has a water-cooled guide plate that performs the original guiding function, and has the necessary stirring power for quality improvement. It is an object of the present invention to provide an electromagnetic stirring device having a compact structure that can be effectively obtained.

In order to achieve the above-mentioned object, the present invention is an electromagnetic stirring device which is responsible for stirring unsolidified molten steel in a slab pulled out from the mold below a continuous casting mold, and which includes a cooling liquid inside. A plurality of guide plates having flow passages are disposed close to and surrounding the slab, and an electromagnetic coil is provided behind each of the guide plates, and the front end surface of the core provided inside each electromagnetic coil is The present invention proposes an electromagnetic stirring device for a continuous casting machine, characterized in that the guide plate and the electromagnetic coil are integrally connected by bolts, and are disposed toward the back side of the guide plate.

With such a configuration, the present invention is capable of preventing breakout, sufficient cooling to prevent bulging, and efficient stirring to obtain a solidified structure with a high equiaxed crystal ratio; a so-called electromagnetic stirring device and a guide device A compact device with a combined configuration is obtained.

Structure of the Invention The present invention will be described in detail below with reference to the drawings.
The present invention is characterized in that a guide plate as a known guide device and an electromagnetic coil are combined into a compact device.

The guide plate 11 shown in the figure is for cooling the slab 1, and as shown in Figs. 4 and 5, a cooling liquid flow path 12 is provided inside, and cooling is generally carried out from a supply tube 13 at the top. Water is introduced and extracted from the lower discharge tube 14 to cool the guide plate 11 itself and at the same time cool the slab 1 to promote solidification. This guide plate 11
are brackets 15, 16 and pins 17, 1
At step 8, the upper side is vertically movably engaged and supported by the lower side of the mold, and the lower side is placed on the saddle 27 provided at the upper end of the segment 20 of the support roll 19, so that the front side is filled with unsolidified molten steel, etc. They are placed close to the slab 1 to be left, and a plurality of them are suspended in a set to surround the slab 1 directly below the mold or at a desired position in the secondary cooling zone.

An electromagnetic coil 21 is integrally arranged behind the guide plate 11. That is, the electromagnetic coil 21 consists of a core 22 and a winding part 23, and the core 22 preferably has a common ring-shaped outer part with a circular or square shape, as shown in FIG. 3 or FIG. Although the support structure is simpler when connected by the member 22a, they may be supported independently or in suspension.

Guide plate 11 and core 2 of electromagnetic coil 21
2 is integrally attached to the core 22 by screwing bolts 24a and 24b from the common member 22a toward the guide plate 11. However, a shim 26 is inserted between the front end surface of the core 22 and the back surface of the guide plate via a bolt 25.
intervene. This shim 26 is used to adjust the gap with the slab 1 when the guide plate 11 is worn out. In the illustrated example, the shim 26 is attached to the front end surface of the core 22, but it may be attached to the guide plate 11 conversely.

In the above-mentioned configuration, if the shim 26 interposed between the front end surface of the core 22 and the guide plates 11, 11' is made of a thick liner, it can be used not only for centering alignment but also for adjustment when changing the size of the slab. is also used.

The electromagnetic stirring device of the present invention described above includes the electromagnetic coil 2
By passing an alternating current through the strand 1, a rotating magnetic field is generated, and the molten steel 10 in the strand can be stirred in a horizontal circular flow as shown by the arrows in FIGS. 3 and 6.

Effects of the Invention As explained above, according to the present invention, it is possible to guide so that breakout does not occur, and also achieve sufficient cooling to prevent bulging, and furthermore, to improve the quality of the slab, it is possible to A solidified structure with a high crystallinity can be obtained. Other features include: () The device is compact because the slab guide device is integrated with the electromagnetic stirring coil body. Therefore, since the coil can be brought closer to the slab than in conventional devices, the stirring effect is improved and the device is downsized by reducing the capacity of the coil.

() Since the slab guide plate has a closed type water cooling mechanism for the slab, it can be installed and used at any location that requires cooling the slab in the secondary cooling zone immediately below the mold.

() The guide device also has a structure that can withstand wear by employing shims, etc., so it can be fully applied to actual operations.

() Since the device is compact, it can be easily installed in an existing continuous casting machine.

[Brief explanation of drawings]

1 and 2 are both schematic diagrams showing known devices, FIG. 3 is a plan view showing an example of the device of the present invention, and FIG. 4 is a schematic diagram showing an embodiment of the device of the present invention. FIG. 5 is an enlarged sectional view of the example shown in FIG.
The figure is a plan view of an embodiment of the invention for casting a round billet. DESCRIPTION OF SYMBOLS 1... Slab, 10... Molten steel, 11... Guide plate, 12... Coolant flow path, 13... Supply tube, 14... Discharge tube, 15, 16...
... Bracket, 17, 18 ... Pin, 19 ... Support roll, 20 ... Segment, 21 ... Electromagnetic coil, 22 ... Coil core, 22a ... Core common member, 23 ... Coil winding part , 24
a, 24b...Bolt, 25...Bolt, 26...
...Sim, 27...saddle.

Claims (1)

[Scope of Claims] 1. An electromagnetic stirring device for stirring unsolidified molten steel inside a slab pulled out from the continuous casting mold below a continuous casting mold, which comprises a plurality of internal cooling liquid flow passages. A number of guide plates are disposed close to and surrounding the slab, and an electromagnetic coil is provided behind each of the guide plates, and the front end surface of the core provided inside each electromagnetic coil is on the back side of the guide plate. An electromagnetic stirring device for a continuous casting machine, characterized in that the guide plate and the electromagnetic coil are arranged so as to face each other and have an integral structure by bolt connection.