JPH0459988B2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention reduces the penetration depth of inclusions contained in the molten steel by slowing down the flow of molten steel from a submerged nozzle in the mold in continuous steel casting. The present invention relates to an electromagnetic brake device that is advantageous in reducing inclusions in slabs.

(Prior Art) In an attempt to reduce inclusions in continuous slabs, for example, Japanese Patent Laid-Open No. 17356/1983 proposes a technique of applying an electromagnetic brake device to a continuous casting mold. This technology specifically slows down the flow of molten steel injected from a submerged nozzle in the mold and prevents inclusions in the molten steel from being trapped at the solidified shell interface of the slab, making it easy to reduce inclusions in the slab. obtain. By the way, there are currently no documents reporting on the specific structure of such an electromagnetic brake device.

(Problems to be Solved by the Invention) The electromagnetic brake device is a mold for continuous casting consisting of a mold copper plate and a cooling box so as to generate a static magnetic field in the thickness direction of the slab at a position near the flow of molten steel discharged from a submerged nozzle. Usually, the mold for continuous casting is fixed to a mold support frame surrounding it via a support shaft, and the mold support frame is mounted on an oscillation table, which is a support frame for the oscillation generator. will be installed in
Alternatively, the mold is installed as a support frame that integrates the support frame with an oscillation table;
Alternatively, the mold support frame is individually held on a support frame.

For this reason, the electromagnetic brake device must be placed inside the cooling box and in the space between the cooling box and the mold support frame.The size of the electromagnetic brake device varies depending on the required deceleration capacity for the molten steel discharge flow, but It takes up more space than it can fit. If a new continuous casting machine is installed on the assumption that an electromagnetic brake device will be installed, this will not be a problem since this installation space can be taken into consideration from the beginning, but if it is installed on an existing continuous casting machine, there will be a shortage of space. There were many things. For this reason, if it is necessary to attach an electromagnetic brake device to such a continuous casting machine, major modifications including the oscillation table must be carried out, which has the disadvantage of requiring a large amount of cost for the modification. In view of these circumstances, an object of the present invention is to propose an electromagnetic brake device with a compact structure that can be easily installed in a small space, especially when the electromagnetic brake device is installed in an existing continuous casting machine.

(Means for Solving the Problems) This invention surrounds the cross-sectional outline of a slab with a mold copper plate, and combines the mold copper plate with a cooling box having a back-up plate along the back surface of the mold copper plate as a main part of the partition wall. In a continuous casting type electromagnetic brake device, the cooling box has a pair of partitioned recesses in the front and rear, each opening facing a mold support frame arranged around the continuous casting mold, and having a back-up plate as the bottom of the opening. A core-containing electromagnetic coil is provided in each compartment recess to form a magnetic path extending between the cores of the electromagnetic coils in the pair of compartment recesses, and the aspect ratio in the direction across the magnetic path is 8 or less. This is a magnetic field brake device for a continuous casting mold, in which a yoke having a longitudinally elongated cross-sectional dimension is fixed together with each core by through bolts that pass through the backup plate and are screwed to the mold copper plate.

FIGS. 1a, b, and 1c show a continuous casting apparatus incorporating a preferred example of an electromagnetic brake device according to the present invention in plan, front, and side views. In the figure, 1 is a mold copper plate that surrounds the cross-sectional outline of the slab, 2 is a cooling box in which the mold copper plate 1 is fixed and the back-up plate 2a is the main part of the partition wall, and 3 is a series consisting of the mold copper plate 1 and the cooling box 2. a mold support frame that holds the casting mold;
4 is a support shaft for fixing the continuous casting mold to the mold support frame 3, 5 is an oscillation table, and 6 is an immersion nozzle.The cooling box 2 has an opening facing the mold support frame 3 and has a backup plate 2a. A pair of compartment recesses 2b at the front and rear are provided as the bottoms of the openings. Also 7
8 is a core-containing electromagnetic coil, 8 is a yoke that forms a magnetic path between the cores of the electromagnetic coils 7, and 9 is a yoke 8, together with the core of each electromagnetic coil 7, that passes through the backup plate 2a and is screwed to the mold copper plate 1. It is a through bolt.

The material of the backup plate 2a between the copper mold plate 1 and the electromagnetic coil 7 is preferably a magnetic material in an area of 0.5 to 2.0 times the dimension of each side of the core with the center of the core of the electromagnetic coil 7 as a reference.

(Function) In order to accommodate an electromagnetic brake device with the required deceleration capacity in a limited space, as shown in Figure 2, the thickness of the copper plate of the mold and the cooling box should be determined based on the dimension a in the thickness direction of the slab, which is the most difficult space. It is necessary to keep the thickness within the dimension (b+δ) obtained by subtracting the thickness of the back-up plate (not shown) at the front surface. Here, δ is required to be the minimum clearance required during assembly and maintenance of the electromagnetic brake device, for example, about 10 mm, so the problem is how to bring dimension b of the electromagnetic brake device closer to dimension a. Furthermore, the electromagnetic brake device is quite heavy and is subject to dynamic loads due to oscillations and the like during operation, so it must be fixed very firmly. Normally, in order to hold the electromagnetic brake device, it is fixed to the backup plate 2a on the front of the cooling box via bolts, but in this case, the backup plate 2a has the disadvantage of being considerably thick and having a small dimension b.

Therefore, in this invention, since the slab thickness g and the mold copper plate thickness f are dimensions that cannot be changed for specifications and cooling reasons, the thickness e of the backup plate 2a is
The size b, which is the installation space for the electromagnetic brake device, is enlarged by making it as small as possible within the range where the strength can be ensured. The electromagnetic brake device is configured by a combination structure of a cored electromagnetic coil 7 that generates a static magnetic field and a yoke 8 having a longitudinal cross-sectional dimension with an aspect ratio (k/j) of 8 or less in the direction across the magnetic path, Among these, the electromagnetic coil 7 is housed in a pair of front and rear divided recesses 2a provided in the cooling box 2, and the yoke 8 and each core are fixed by through bolts 9 that pass through the backup plate 2a and are screwed to the mold copper plate 1. Because it is designed to do so, it can be easily installed even in existing continuous casting machines with limited installation space. The reason why the yoke 8 has a vertically long cross-sectional dimension with an aspect ratio (k/j) of 8 or less is that in order to prevent the magnetic field generated by the electromagnetic coil 7 from becoming saturated, the cross-sectional area of the yoke 8 must be equal to or larger than that of the core. However, as mentioned above, there are restrictions on dimension b in existing continuous casting machines. Therefore, the yoke 8 was made to have a vertically elongated cross-sectional shape (j<k), and the necessary cross-sectional area was secured with a dimension k in the height direction that provided sufficient space (see FIG. 1). Especially the aspect ratio (k/j)
The reason why is limited to 8 or less is that if the aspect ratio exceeds 8, the magnetic path resistance increases and the efficiency of the electromagnetic brake device decreases significantly.

The cooling box 2 that houses the electromagnetic coil 7 is usually made of non-magnetic steel in order to prevent leakage of magnetic flux to the surrounding area, but in this invention, it is made of electromagnetic steel in order to shorten the interval (dimension c) between the magnetic poles of the electromagnetic braking device. The backup plate 2a in contact with the core portion of the coil 7 is preferably made of magnetic steel in an area of 0.5 to 2 times the core dimension i×h.

The reason why the above region is made of magnetic steel is that if it is less than 0.5 times the dimension of each side of the core, the dimension c will be substantially short;
This is because the effect of reducing steam resistance is small, and if it exceeds twice that, leakage magnetic flux will increase.

Next, the electromagnetic brake device is mounted using a through bolt 9 that passes through the yoke 8 and the core of the electromagnetic coil 7 and is screwed onto the molded copper plate 1. It is possible to provide the threaded portion of the through-bolt 9 on the back-up plate 2a side of the cooling box 2, but in order to make the dimension b as large as possible, the thickness e of the back-up plate 2a is kept to a minimum to hold the electromagnetic brake device. It is not possible to obtain sufficient dimensions to ensure sufficient strength. Therefore, the threaded portion of the through bolt 9 should be on the molded copper plate 1 side where sufficient strength can be ensured. However, the weight of the electromagnetic brake device is quite heavy, and the strength of the threaded portion between the through bolt 9 and the steel plate 1 alone is not sufficient, so it is desirable to use an auxiliary fixing device.
As shown in Figure 1, this auxiliary fixing device secures the electromagnetic brake device by sandwiching it between the top and bottom, and since the weight of the device itself reduces the load on the through bolt 9 and the screwed part, it can withstand dynamic loads by oscillation, etc. Stable support can be achieved. FIG. 3 shows an enlarged view of the main parts of the auxiliary fixing device shown in FIG.
0a and a push bolt 10b.
The fixing position and the number of fixing parts are not particularly limited, but in order to achieve stable fixing, it is preferable to fix them near four points at the corners of the yoke 8.

If the pull bolt 10a and the push bolt 10b are used in combination, by adjusting these, it is possible to easily center the holding plate 10c as a reference surface or a guide surface when installing the electromagnetic brake device.

(Effects of the Invention) According to the present invention, when applied to an ordinary existing continuous casting machine that is not equipped with an electromagnetic brake device, the installation space, including at least the mold support frame, oscillation table, etc., requires significant modification. It is possible to incorporate an electromagnetic brake device without the need for a caster, reducing the cost and time required for modification, and even when applied to a newly installed continuous casting machine, the mold can be designed compactly by applying the electromagnetic brake of this invention. The oscillation device connected to the mold can also be downsized, saving space and significantly reducing equipment construction costs.

[Brief explanation of the drawing]

Figures 1 a, b, and c are front and side views of the electromagnetic brake device according to the present invention, Figure 2 is an explanatory diagram of the installation of the electromagnetic brake device, and Figure 3 is an enlarged view of the main parts of the auxiliary fixing device. ... Mold copper plate, 2 ... Cooling box, 3 ... Mold support frame, 4 ... Support shaft, 5 ... Oscillation table, 6 ... Immersion nozzle, 7 ... Core-containing electromagnetic coil, 8 ... Yoke , 9... Penetration bolt, 10...
Bracket.

Claims (1)

[Claims] 1. Electromagnetic continuous casting mold in which a copper mold plate surrounds the cross-sectional outline of a slab, and a cooling box is combined with the copper mold plate, and a back-up plate along the back side of the copper mold plate is used as a main part of the partition wall. In the brake device, the cooling box is provided with a pair of compartment recesses in each of the front and rear, each opening facing a mold support frame disposed surrounding the continuous casting mold, and having a back-up plate as the bottom of the opening. A core-containing electromagnetic coil is housed in the chamber to form a magnetic path extending between the cores of the electromagnetic coils in the pair of partitioned recesses, and a longitudinal cross-sectional dimension with an aspect ratio of 8 or less in the direction across the magnetic path. What is claimed is: 1. An electromagnetic brake device for a continuous casting mold, characterized in that a yoke having a yoke and each core is fixed by through bolts that pass through a backup plate and are screwed to a copper plate of the mold. 2. Regarding the material of the backup plate between the mold copper plate and the electromagnetic coil, Claim 1 in which the backup plate covering an area of 0.5 to 2 times the dimension of each side of the core based on the core center of the electromagnetic coil is made of a magnetic material. An electromagnetic brake device for a continuous casting mold as described in Section 1.