JP5021560B2 - Casting equipment for continuous casting - Google Patents

Description

  The present invention is a continuous for effectively using an electromagnetic coil (hereinafter referred to as a combined electromagnetic coil) capable of selectively applying an electromagnetic brake or electromagnetic stirring to molten steel in a mold during continuous casting of steel. The present invention relates to a casting mold facility.

  In continuous casting of steel, in order to improve the quality of a slab, electromagnetic force such as electromagnetic stirring that stirs molten steel in a mold is applied, and many proposals have been made conventionally.

For example, Patent Documents 1 to 3 propose an electromagnetic stirring device and an application method thereof.
JP-A-62-203648 JP-A-63-188461 Japanese Patent Laid-Open No. 10-5949

Patent Documents 4 and 5 propose dual-purpose electromagnetic coils for improving the quality of the slab surface layer by electromagnetic stirring of molten steel in the mold and for ensuring proper operation stability by discharge flow braking during high-speed casting. Yes.
JP 2004-322179 A JP 2005-349454 A

  These dual-purpose electromagnetic coils of Patent Documents 4 and 5 are provided with an inner winding on each of 2n teeth (n is a natural number of 2 or more, the same applies hereinafter) arranged on each long side of the mold, and further outward from the outside. It consists of n electromagnetic coils that are wound together. By adopting such a configuration, it is possible to use both electromagnetic stirring and molten steel flow control of an electromagnetic brake with a single electromagnetic coil.

  However, the inventions proposed in Patent Documents 1 to 5 are all inventions related to electromagnetic coils, and the contents related to the coil body are disclosed. However, regarding the mold for housing and arranging the electromagnetic coils, no disclosure or There is no suggestion.

  In order to enhance the stirring effect when electromagnetically stirring the molten steel in the mold, a method of increasing the magnetic flux density in the meniscus by bringing the iron core of the electromagnetic coil as close as possible to the molten steel surface (meniscus) is known.

  However, the electromagnetic coil has a configuration in which the iron core is wound and the space on the upper end side of the coil is limited. Therefore, when the iron core is brought close to the meniscus, the drainage chamber cannot be installed on the upper part of the mold. It becomes difficult to provide the cooling water flow path in the upper part of the mold.

Therefore, proposals have been made to devise the mold structure and electromagnetic coil so that the iron core of the electromagnetic coil can be brought close to the meniscus. For example, Patent Document 6 discloses a mold in which an iron core is provided below a storage chamber of a mold cooling box and a cooling water channel is devised in order to make the iron core as close as possible to the meniscus. ing.
Japanese Utility Model Publication No. 58-49172

Further, in Patent Document 7, the drainage flow path after cooling the mold is processed in a horizontal plane direction above the casting direction in the fixing plate of the mold copper plate, and a continuous casting mold in which drainage headers are provided on both sides of the mold. Is disclosed.
JP 2005-305476 A

  However, the mold disclosed in Patent Document 7 has a problem that the drainage groove into the fixing plate of the mold copper plate has to be formed by a special hole processing, and the processing difficulty is high and the manufacturing cost is high. There is.

  Further, the rigidity of the fixing plate is reduced by the hole processing, and since there is no cooling box at the upper part of the mold, the fixing plate cannot be supported from the back side, so that the rigidity of the entire mold is reduced. Therefore, the thickness of the fixing plate for the mold copper plate must be increased to cope with it, and the electromagnetic coil and the molten steel are separated from each other, resulting in a decrease in magnetic flux density.

On the other hand, a mold is disclosed in which a coil winding portion of an iron core is cut out and wound to ensure a space above the electromagnetic coil and to raise the iron core to the meniscus as much as possible (for example, Patent Documents). 8).
JP 2007-136537 A

  However, in the structure disclosed in Patent Document 8, the iron core of the coil winding portion becomes thinner by the amount of the notch of the iron core, which leads to a decrease in magnetic flux density.

  Further, in the case of the dual-purpose electromagnetic coil disclosed in Patent Documents 4 and 5 shown in FIG. 3A, the tooth portion 1 b (of the coil winding portion) protruding from the yoke portion 1 a constituting the iron core (core portion) 1. The iron core becomes thinner and the magnetic flux density decreases. Moreover, the space for winding the thick inner and outer windings 2a and 2b having a diameter of about several tens of millimeters, which includes the cooling water flow path, can hardly be formed by the degree of the notch.

  Therefore, like the electromagnetic coil disclosed in Patent Document 8 shown in FIG. 3A, the space for installing the drainage chamber above the electromagnetic coil by lowering only the winding portion of the winding 2 in the iron core 1. Is difficult to secure, and as a result, a great result of increasing the stirring force cannot be obtained.

  The problem to be solved by the present invention is that the dual-purpose electromagnetic coil is difficult to cut out the tooth portion, and only the teeth portion is lowered to secure a space for installing the drainage chamber above the dual-purpose electromagnetic coil. That is difficult.

The casting equipment for continuous casting of the present invention is
In order to store and install in a mold without reducing the electromagnetic stirring ability of the combined electromagnetic coil disclosed in Patent Documents 4 and 5 without reducing the mold cooling capacity,
Continuously casting steel by selectively applying an electromagnetic brake or electromagnetic stirring to the molten steel in the mold by passing a direct current or multiphase alternating current of two or more phases to the electromagnetic coil placed on the back side of the long side of the mold A casting apparatus for continuous casting used in the method,
A mold in which a fixing plate is arranged in contact with the back side of the mold copper plate;
Each long side of the mold has 2n teeth (n is a natural number of 2 or more), and each of the teeth is wound on the inner side. Comprising n electromagnetic coils with outer windings applied from the outside of the windings;
A cooling water supply chamber for cooling the mold copper plate is disposed below the electromagnetic coil, and a drain chamber is disposed above the electromagnetic coil in contact with the fixing plate. On the back side, a cooling water flow path connected to the water supply chamber is provided in the casting direction. On the fixing plate, cooling drainage after passing through the cooling water flow path is perpendicular to the cooling water flow path from the inlet . leading to the discharge chamber through the horizontal drainage passage provided in the horizontal direction, setting the drain passage casting direction length Lz to (mm) satisfies the following formula,
The most important feature is that a non-magnetic mold copper plate pressing plate is disposed above the mold copper plate so as to be at the same height as the fixing plate.
Lm <Lz ≦ 0.3 × Lbp
Here, Lm is the distance (mm) from the molten steel surface position (meniscus) to the upper end of the casting copper plate, and Lbp is from the lower end of the cooling water passage provided on the casting copper plate to the upper end of the drainage passage provided on the fixing plate. Distance (mm).

  In the present invention, the n number of combined electromagnetics obtained by further applying the outer winding from the outside of the inner winding applied to each of the 2n teeth arranged on each long side of the mold without reducing the mold cooling ability. A decrease in magnetic flux density at the meniscus of the coil can be minimized.

Hereinafter, the best mode for carrying out the present invention will be described together with the process from the idea of the present invention to the solution of the problem.
The inventors studied the optimum mold shape for installing the dual-purpose electromagnetic coil.

  Each of the 2n teeth portions arranged on each long side of the mold is provided with an inner winding, and in the n number of dual-purpose electromagnetic coils further provided with an outer winding from the outside of the inner winding, the positions of the meniscus and the iron core When aligning, the space for the inner and outer windings is required at the top of the tooth portion.

  Therefore, when the drainage chamber is provided on the upper part of the dual-purpose electromagnetic coil, as shown in FIG. 2 of Patent Document 8, the upper end of the mold copper plate is extended above the meniscus, and from the meniscus to the upper end of the mold copper plate. The distance becomes longer.

  As a result of investigation by the inventors, in the mold copper plate in which the cooling water flow path is formed in the entire casting direction, when the distance from the upper end to the meniscus becomes long, the magnetic flux escapes to the upper part of the mold copper plate not in contact with the molten steel, and the meniscus It was found that the magnetic flux that contributes to stirring is reduced. Therefore, in order to stir the molten steel efficiently, the distance between the upper end of the mold copper plate and the meniscus must be as short as possible.

Therefore, the inventors conducted extensive studies on the structure of the drainage channel from the mold copper plate.
As a result, as shown in FIG. 1, the distance Lm from the meniscus 11 to the upper end 12a of the mold copper plate 12 is shortened as much as possible, and a space for providing the drainage chamber 14 above the dual-purpose electromagnetic coil 13 is as follows. (1) The drainage channel structure of (2) was found to be appropriate.

(1) The fixing plate 15 arranged in contact with the back side of the mold copper plate 12 is provided with an inlet 15a for cooling drainage that has passed through the cooling water passage 12b in the casting direction formed on the back side of the mold copper plate 12.

(2) In order to connect the cooling drainage inlet 15a and the drainage chamber 14 to the fixing plate 15, a horizontal drainage channel 15d provided in a horizontal direction perpendicular to the cooling water channel 12b and drainage toward the upper part in the casting direction. A flow path 15b is provided. The drainage flow path 15b can be easily manufactured by, for example, machining a hole in the vertical direction from the upper part of the fixing plate 15, and closing the upper part with a shielding plug or welding after the machining.

  In the drainage channel structure, the distance Lm from the upper end 12a of the mold copper plate 12 to the meniscus 11 and the casting direction length Lz of the drainage channel 15b provided in the fixing plate 15 are as follows. It can be defined by equation (A).

  Lm <Lz (A)

  By the way, in the case of this drainage channel structure, compared with the structure of FIG. 2 of Patent Document 8 in which a horizontal drainage channel from the cooling water channel of the mold copper plate to the drainage chamber is provided on the fixing plate. There is a concern that the line will become complicated and pressure loss will increase, resulting in a shortage of cooling water.

  Therefore, the inventors compared the pressure loss of the cooling water under the drainage channel conditions shown in Table 1 below. The results are also shown in Table 1.

As shown in Table 1, the invention example has an increase in pressure loss of about 0.5 kgf / cm ² compared to the structure (comparative example) shown in FIG. It is estimated to be.

This is because if the pressure loss increases by about 0.5 kgf / cm ² , if there is a margin in the pump capacity, it can be handled by increasing the amount of water delivered. Even if the pumping capacity is insufficient, for example, in the case of the conditions shown in Table 1, if processing is performed to increase the depth of the cooling water flow path 12b of the mold copper plate 12 by about 2 mm, the total pressure loss in the mold cooling water flow path system is reduced. This is because the sum is equivalent.

  As a result of studying the pressure loss on the drain side of the fixing plate 15 among the above problems, the inventors obtained the relationship shown in FIG. The specifications of the drainage channel that obtained the results of FIG. 2 were as shown in Table 1 except for the casting direction length Lz of the drainage channel 15b.

In FIG. 2, the pressure loss increase margin on the drain side is desirably 1 kgf / cm ² or less with respect to the drain flow path structure (Lz / Lbp = 0) shown in FIG. This is because if it is 1 kgf / cm ² or less, the flow rate can be secured with the remaining capacity of the pump capacity. Further, the required flow rate can be accommodated by reducing the pressure loss by slightly increasing the depth of the cooling water passage 12b of the mold copper plate 12.

On the other hand, if it exceeds 1 kg / cm ² , for example, it is necessary to make the depth of the cooling water flow path 12b of the mold copper plate 12 as deep as 4 to 5 mm, and the slab heat removal conditions will change greatly.

  The inventors arranged the ratio (Lz / Lbp) of the length Lz in the casting direction of the drainage channel 15b and the distance Lbp from the lower end of the cooling channel 12b to the upper end of the drainage channel 15b to cast the drainage channel 15b. It has been found that the direction length Lz can be defined by the equation (B).

  Lz ≦ 0.3 × Lbp (B)

  In the case of the drainage channel structure, the fixing plate 15 is extended upward, and the distance between the meniscus 11 and the upper end 12a of the mold copper plate 12 is increased.

  In this case, for example, in the initial stage of casting, it is difficult to visually check the molten metal surface in the adjustment of the amount of molten steel supplied into the mold by the operator and the removal of the molten steel skinned part in the mold. As a result, the hot water supply adjustment at the initial stage of casting fails, and there is a possibility that an operation trouble due to the overflow of molten steel to the upper part of the mold or the solidification failure due to the remaining skin coating may occur.

  Further, when the length Lz in the casting direction of the drainage flow path 15b of the fixing plate 15 is long, there is a concern that the rigidity of the fixing plate 15 is lowered as in the mold cooling water flow path structure disclosed in Patent Document 7.

  From the above, it is preferable that the casting direction length Lz of the drainage flow path 15b of the fixing plate 15 is as short as possible within the range of the conditions satisfying the expressions (A) and (B).

  In the case of such a drainage channel structure, the cooling water fed to the water supply chamber 16 from one or both sides in the width direction of the mold is supplied to the cooling water flow of the mold copper plate 12 via the water supply channel 15 c provided in the fixing plate 15. Guided to the path 12b, the mold copper plate 12 is cooled.

The cooling drainage after cooling the mold copper plate 12 flows into the inlet portion 15a provided in the fixing plate 15 of the mold copper plate 12, and is then led to the drainage chamber 14 through the horizontal drainage channel 15d and the drainage channel 15b. The water is drained from the drainage chamber 14, and interference with the installation space of the dual-purpose electromagnetic coil 13 can be eliminated.

  The mold equipment for continuous casting according to the present invention has been made based on the above knowledge and has the following configuration.

The casting equipment for continuous casting of the present invention is
A mold in which a fixing plate 15 is arranged in contact with the back side of the mold copper plate 11;
Each long side of the mold has 2n teeth portions, and each teeth portion is provided with an inner winding, and in order to unite these two teeth portions further from the back side of the inner winding. There are provided n number of electromagnetic coils 13 that are wound.

  A cooling water supply chamber 16 for cooling the mold copper plate 12 is in contact with the fixing plate 15 at a position below the dual-purpose electromagnetic coil 13 and a drainage chamber 14 is in a position above the dual-purpose electromagnetic coil 13. It is arranged.

On the other hand, a cooling water flow path 12b connected to the water supply chamber 16 is provided on the back side of the mold copper plate 12 in the casting direction. In addition, the drainage of the cooling water after passing through the cooling water flow path 12b is passed through the fixing plate 15 via a horizontal drainage flow path 15d provided in a horizontal direction perpendicular to the cooling water flow path 12b from the inlet portion 15a. A drainage flow path 15b that leads to the chamber 14 and has a length Lz (mm) in the casting direction satisfying Lm <Lz ≦ 0.3 × Lbp is provided in the casting direction.

  In such a continuous casting mold facility, the distance Lm from the meniscus 11 to the upper end 12a of the mold copper plate 12 is, as described above, to minimize the decrease in magnetic flux density at the meniscus 11 due to the magnetic flux escaping upward. It is necessary to make it as small as possible.

  On the other hand, when the distance to the upper end 12a of the mold copper plate 12 is too small, the molten steel 17 may exceed the upper part of the mold copper plate 12 when the meniscus 11 changes due to the change in the amount of molten steel supplied into the mold. In this case, there is a concern that the molten steel 17 is restrained on the upper part of the mold copper plate 12 and the solidified shell is broken.

  Therefore, in the present invention, the distance Lm from the meniscus 11 to the upper end 12a of the mold copper plate 12 is preferably 50 to 100 mm.

  Moreover, even if the molten steel 17 exceeds the upper part of the mold copper plate 12, it is important that the molten steel 17 adheres and does not generate any restraint. Therefore, in the present invention, the mold copper plate pressing plate 18 is installed on the upper part of the mold copper plate 12. The mold copper plate pressing plate 18 needs to be made of a non-magnetic material so that the magnetic flux does not escape upward.

  It goes without saying that the present invention is not limited to the above-described examples, and the embodiments may be appropriately changed within the scope of the technical idea described in each claim.

  The above-described present invention can be applied to any type of continuous casting mold such as a curved type and a vertical type as long as it is continuous casting.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which shows the casting_mold | template for continuous casting of this invention, (a) is the side view seen from the casting_mold | template short side, (b) is an arrow AA figure of (a). It is a figure which shows an example of the pressure loss by the side of the waste_water | drain in the plate for fixation. (A) is a figure which shows the outline | summary of the electromagnetic coil shown by patent document 4, 5, (b) is a figure which shows the outline | summary of the electromagnetic coil shown by patent document 8, The figure seen from the plane direction respectively on the paper surface, The lower side of the drawing is a view seen from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Meniscus 12 Mold copper plate 12a Upper end 12b Cooling water flow path 13 Combined electromagnetic coil 14 Drain chamber 15 Fixing plate 15a Cooling drain inlet 15b Drain flow path
15d Horizontal drainage channel 16 Water supply chamber 17 Molten steel 18 Mold copper plate presser plate

Claims (1)

Continuously casting steel by selectively applying an electromagnetic brake or electromagnetic stirring to the molten steel in the mold by passing a direct current or multiphase alternating current of two or more phases to the electromagnetic coil placed on the back side of the long side of the mold A casting apparatus for continuous casting used in the method,
A mold in which a fixing plate is arranged in contact with the back side of the mold copper plate;
Each long side of the mold has 2n teeth (n is a natural number of 2 or more), and each of the teeth is wound on the inner side. Comprising n electromagnetic coils with outer windings applied from the outside of the windings;
A cooling water supply chamber for cooling the mold copper plate is disposed below the electromagnetic coil, and a drain chamber is disposed above the electromagnetic coil in contact with the fixing plate. On the back side, a cooling water flow path connected to the water supply chamber is provided in the casting direction. On the fixing plate, cooling drainage after passing through the cooling water flow path is perpendicular to the cooling water flow path from the inlet . leading to the discharge chamber through the horizontal drainage passage provided in the horizontal direction, setting a discharging water flow path casting direction length Lz to (mm) satisfies the following formula,
A continuous casting mold facility, wherein a non-magnetic mold copper plate pressing plate is disposed above the mold copper plate so as to be at the same height as the fixing plate.
Lm <Lz ≦ 0.3 × Lbp
Here, Lm is the distance (mm) from the molten steel surface position (meniscus) to the upper end of the casting copper plate, and Lbp is from the lower end of the cooling water passage provided on the casting copper plate to the upper end of the drainage passage provided on the fixing plate. Distance (mm).

Images