JP3570401B2 - Magnetic field generator for continuous casting of steel and continuous casting method of steel - Google Patents

Description

【００４５】
表１に示したとおり、本発明によれば、従来問題となっていた超伝導コイルへの負荷荷重やコイル内部温度上昇を効果的に改善することができ、その結果、鋳型振動数の増加が可能となり、またネガティブストリップ率を高くしてブレークアウト発生率を低減する上でも有利となる。
【００４６】
【発明の効果】
かくして、本発明によれば、高い振動数でのオシレーション（鋳型振動）が可能となり、その結果、高速の連続鋳造で高品質の鋳片の製造が可能となる。
【図面の簡単な説明】
【図１】鋳型反力の発生原理を示す図である。
【図２】従来の超伝導コイルのサポート要領を示す図である。
【図３】本発明に従う超伝導コイルの内部構造を示す平面図（ａ） 、正面図（ｂ）および背面図（ｃ） である。
【図４】３本の引っ張り索条によって超伝導コイルを支持する要領を示す図である。
【図５】磁石内コイルに取りつけたＣＧＲ温度センサーの抵抗値と温度との関係を示す図である。
【図６】２つのＣＧＲ温度センサーで測定した連続鋳造操業における経過時間と磁石内部のＣＧＲ測定値との関係を示した図である。
【図７】超伝導磁石に対する熱遮断体の設置状態の説明図である。
【図８】超伝導磁石の外壁の全部を熱遮断体で構成する場合の説明図である。
【図９】超伝導線（ＮｂＴｉフィラメント）の線径を種々に変更した場合の線径と消磁時間との関係を示すグラフである。
【図１０】本発明を適用した連続鋳造機の模式図である。
【符号の説明】
１ 鋳型
２ 超伝導磁石コイル
３ 磁場
４ 誘導電流
５ 鋳型反力
６ サポート材
７ コイルケース
８ 水平索条
９ 引っ張り索条
１０ 真空容器
１１ 冷凍機
１２ 金属板
１３ 断熱シート
１４ 超伝導磁石
１５ 熱遮断体
１６ 熱遮断体で構成された外壁
１７ 浸漬ノズル
１８ 溶鋼
１９ モールドパウダー
２０ ロール[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for generating a magnetic field for continuous casting of steel and a method of continuously casting steel using the same, and more particularly to an efficient production of high quality cast slabs.
[0002]
[Prior art]
In continuous casting, a molten metal (molten metal), for example, molten steel is generally injected from a tundish through an immersion nozzle into a mold.
However, since the molten steel discharged from the discharge port of the immersion nozzle has a large discharge flow rate, inclusions such as alumina and air bubbles may be caught in the steel, which contributes to product defects. Was. Such defects caused by inclusions such as inclusions and air bubbles have a strong correlation with the discharge flow rate of molten steel, and as the discharge flow rate increases, product defects also increase. At present, the molten steel discharge rate has reached 4 to 6 ton / min, but it is difficult to increase the discharge rate further unless radical improvement of the continuous casting method is performed.
[0003]
Also, at the time of molten steel injection, the discharge flow collides with the short side of the mold. When this impinging flow is regenerated into an upward flow along the short side wall of the mold, the upward flow disturbs the molten metal surface, and as a result, mold flux and the like added to the molten metal surface are caught in the steel. This was a cause of quality deterioration.
[0004]
Until now, such problems have been addressed by devising the shape and discharge angle of the nozzle discharge port to slow down the molten steel discharge flow.In recent years, while satisfying even higher quality requirements of users, There is a tendency to increase the throughput (casting amount) for higher efficiency and higher economic efficiency. For this purpose, the conventional measures are not sufficient, and the development of a new casting method has been desired.
[0005]
As a prior art relating to this point, there is known a technique of applying a static magnetic field (static magnetic field by a normal magnet) to molten steel in a mold and applying a braking to the molten steel discharge amount to prevent intrusion of inclusions into the steel. (For example, JP-A-8-52549, JP-A-8-19841, JP-A-57-17356, JP-A-2-284750, etc.).
However, in these prior arts, although the direction of the molten steel jet can be changed, the energy of the jet cannot be dispersed to form a uniform flow. In some cases, molten steel escapes to a region where there is no static magnetic field. Further, although a quality improvement effect can be obtained up to a throughput of about 4 to 5 ton / min, there is a problem that the effect cannot be expected with a throughput exceeding this.
[0006]
As an attempt to overcome such a problem, Japanese Patent Application Laid-Open Nos. 8-90176 and 8-229648 have proposed a continuous casting method of steel using a superconducting magnet. The above problem during operation can be advantageously solved.
[0007]
By the way, as is well known, in continuous casting, the mold is vibrated to improve the lubrication between the mold and the slab. Therefore, in order to increase the casting speed, it is necessary to increase one or both of the stroke and the frequency of the mold vibration (called oscillation).
However, if the stroke is too large, there is a possibility that solid powder may be entrained in the molten steel meniscus portion in the mold or blockage of the powder flow path by the slag rim, so that the length is usually 10 mm or less.
Therefore, it is necessary to increase the frequency of mold vibration from the viewpoint of increasing the casting speed.
Also, from the viewpoint of the slab surface properties, increasing the mold frequency has the advantage that the depth of the on-line mark can be reduced.
[0008]
However, in a casting method using a superconducting magnet, a magnetic field is extremely large as compared with a conventional normal magnet, and when a mold is vibrated in this magnetic field, a large reaction force is generated in a counter-vibration direction. This reaction force is proportional to the strength of the magnetic field, the speed of the object, and the electric conductivity according to Faraday's law.
On the other hand, as described above, it is desirable to perform casting at a higher speed for quality and casting stability, and accordingly, it is necessary to increase the vibration frequency of the mold to some extent. The power is extremely large. For example, when the magnetic field strength is 1 T and the mold vibration frequency is 120 cpm, the reaction force reaches 1 ton or more.
Therefore, a large load is applied to the actuator for exciting the mold, and this load is further increased particularly when an attempt is made to increase the frequency or to increase the stroke.
[0009]
Further, according to Newton's third law (law of action / reaction), the above reaction force is applied not only to the mold but also to the superconducting magnet which is a magnetic field source. Therefore, an excessive force acts on the coil of the superconducting magnet and the support material supporting the coil.
For this reason, even if high-speed casting and high-throughput production are attempted while maintaining high quality using superconducting magnets, such high-speed casting and high-throughput production cannot be performed in practice. is the current situation.
[0010]
[Problems to be solved by the invention]
The present invention has been developed in view of the above-mentioned current situation, and a magnetic field generator for continuous casting of steel that enables onlation (mold vibration) at a high frequency and that enables continuous casting at high speed, It is intended to propose a method together with a continuous casting method of steel using the same.
[0011]
[Means for Solving the Problems]
As in the past, in casting using a static magnetic field with a normal magnet, the magnetic field was not so strong, and the casting speed, throughput, etc. were small, so that the mold vibration frequency was not high. Therefore, the mold reaction force did not matter.
However, when performing a high-speed casting by applying a static magnetic field using a superconducting magnet, the operation of the mold is hindered because the mold reaction force increases as described above.
[0012]
FIG. 1 is an explanatory view of the principle of generating a mold reaction force. In the drawing, reference numeral 1 denotes a mold, 2 denotes a superconducting magnet coil, and a magnetic field 3 generated by the superconducting magnet coil 2 vibrates the mold 1 under a state where the magnetic field 3 vertically penetrates the long side wall of the mold 1. Then, the induced current 4 flows inside the mold. The interaction between the induced current 4 and the magnetic field 3 generates a mold reaction force 5.
As described above, when the copper plate is vibrated in the magnetic field, a very large reaction force acts on the copper plate.
[0013]
In order to solve this problem, the inventors first used a plate having a low electric conductivity as a plate constituting the mold, and used a low electric conductive material or an insulating material as a part of the plate, thereby reducing the vibration of the mold. A method for reducing the mold reaction force at the time was proposed (Japanese Patent Application No. 11-36748).
According to this method, the mold reaction force can be reduced, and the load on the drive system of oscillation can be reduced.
[0014]
However, even in this method, there still remains a problem that the support portion of the superconducting magnet coil is fatigued by the influence of the mold reaction force.
In this regard, if the superconducting magnet is vibrated in synchronization with the mold, there is no relative movement with the mold, so that there is no reaction force to the coil in the superconducting magnet.
Therefore, the inventors conducted intensive studies on a magnetic field generator having a structure suitable for applying a magnetic field while oscillating the superconducting magnet in synchronization with the mold, and completed the present invention after trial and error. It has been reached.
[0015]
That is, the gist configuration of the present invention is as follows.
1. A magnetic field generator for generating a static magnetic field in a direction opposite to a long side wall of a continuous casting mold, comprising an annular air-core superconducting coil, a coil case for fixing the coil, and a vacuum for the coil case. A plurality of cords to be locked at predetermined positions in the container, a refrigerator connected to the superconducting coil via a metal connector, and the coil kept at a cryogenic temperature by conduction cooling; Equipped with a vacuum device that controls the decompression of
A magnetic field generator for continuous casting of steel, characterized in that the coil case is supported from the back by horizontal ropes having a double cylindrical structure and supported by at least three pulling ropes from above and below.
[0016]
2. The magnetic field generator for continuous casting of steel according to 1 above, wherein the coil case is supported from above and below by at least three pull cords on the back side of the coil case.
[0017]
3. The magnetic field generator for continuous casting of steel according to 1 or 2, wherein a heat shield is provided outside the magnetic field generator to block radiant heat from the slab.
[0018]
4. In the above 1, 2, or 3, continuous NbTi superconducting wire having a wire diameter of 5 μm or less is wound in a race track shape, and after winding, a coil is integrated by vacuum impregnation with epoxy resin. Magnetic field generator for casting.
[0019]
5. When performing continuous casting of steel using a continuous casting mold provided with the magnetic field generator according to any one of the above 1 to 4, the synchronous magnetic field generator and the mold are generated from the magnetic field generator while synchronously vibrating. A continuous casting method for steel, wherein the flow of molten steel in a mold is controlled using a strong static magnetic field.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described specifically.
In the present invention, an object is to apply a strong magnetic field to a mold, and a superconducting magnet is used for that purpose. As such a superconducting magnet, an NbTi superconducting wire is wound by a solenoid winding in a race track shape having a width exceeding the mold width so that the required number of turns is uniform in the mold width direction. It is preferable to use a coil integrated by vacuum impregnation. Next, the coil having the shape of a race track is stored in a cryostat (cryogenic vessel), and cooling for superconducting state is performed. Then, two or four such superconducting coils are connected in series, both ends of which are connected to a current introduction terminal of a cryostat, and excitation is performed using an excitation power supply attached to the superconducting magnet.
[0021]
Thus, the superconducting coil of the present invention is an annular air-core coil, and does not have an iron core unlike a normal-conduction electromagnetic coil. One of the reasons for this is to reduce the total weight of the coil as described in Japanese Patent Application Laid-Open No. Hei 8-229651, but in a strong magnetic field generated by a superconducting coil, the strength of the magnetic field of the iron core is saturated. Because it has no effect.
[0022]
The inventors have studied a magnet structure that can appropriately vibrate a superconducting magnet in synchronization with a mold.
The problem here is how to prevent the vibration of the coil. Since a superconducting coil has no iron core and is air core, it is usually supported by a plurality of support parts.
That is, conventionally, as shown in FIG. 2, the structure was simply suspended by the support member 6.
However, in this structure, when the superconducting coil is vibrated in synchronization with the mold, the superconducting coil does not stop at a predetermined position when moving upward, but moves upward, and when moving downward, the support material 6 Since the load is excessively applied, there is a concern that the support member 6 may be broken.
[0023]
Therefore, in the present invention, the following structure is adopted to realize appropriate vibration of the superconducting magnet synchronized with the mold.
First, the superconducting magnet coil is fixed with a non-magnetic coil case (preferably, a stainless steel (SUS 304) coil case). This is to prevent the coil from being deformed by vibration. Also, when two sets of coils are used to apply two upper and lower magnetic fields, it is necessary to suppress the repulsive force acting between the two sets of upper and lower coils.
Then, as shown in FIGS. 3A to 3C, the coil case 7 is supported together with the superconducting magnet coil 2 by the horizontal ropes 8 and the pulling ropes 9, so that the vacuum container of the coil case 7 is formed. The fluctuation in the horizontal and vertical planes from a predetermined position in the position 10 is prevented even under a vibration state.
[0024]
That is, the horizontal cable 8 has a double cylindrical structure composed of an inner tube made of carbon FRP and an outer tube made of glass FRP surrounding the inner tube, and the tensile force is applied to the inner tube made of carbon FRP, while the outer tube made of glass FRP is used. By supporting the coil case 7 from the back side with the horizontal cable 8 having such a double cylindrical structure, the coil case 7 can mainly support the opposing coils in the vacuum vessel 10. Fluctuation in the horizontal direction from a predetermined position due to electromagnetic forces acting on each other can be effectively prevented.
[0025]
On the other hand, the fluctuation in the vertical plane can be prevented by pulling and supporting from at least three (four in this example) pull cords 9 from above and below.
FIG. 3 shows a case where the coil case 7 is supported by the four pull cords 9. However, as shown in FIG. 4, if there are at least three pull cords 9, the coil case 7 in the vacuum vessel 10 is provided. Can be effectively prevented from fluctuating in the vertical plane from the predetermined position.
In FIG. 3 (b), the pull cords 9 are slightly inclined to make them easy to see, but they are actually installed almost vertically.
[0026]
Here, the material of the horizontal cord and the pull cord is not particularly limited, but the above-mentioned FRP (carbon fiber or glass thread fiber reinforced plastic) is desirable from the viewpoint of strength and heat conduction. That is, the heat conduction is small and each wire has a strength of about 1.0 to 1.5 × 10 ⁴ N.
[0027]
In FIG. 3, reference numeral 11 denotes a refrigerator. The refrigerator 11 is connected to the superconducting coil 2 via a metal coupling body 12 made of Al or Cu, and the coil 2 is cooled to an extremely low temperature by conduction cooling. Can be held. In addition, as the refrigerator 11, a two-stage refrigerator is suitable.
Here, the two-stage refrigerator has a two-stage structure in which the heat absorbing portion of the refrigerator main body has a one-stage stage (80 K level heat absorbing portion) and a two-stage stage (4 K level heat absorbing portion). The first stage is used for cooling the radiation shield plate, and the second stage is used for cooling the superconducting coil.
[0028]
By using such a conduction cooling type refrigerator, liquid helium which has been conventionally used in order to make the superconducting coil 2 operable at 4 to 5K becomes unnecessary, so that the entire apparatus can be downsized. As a result, it was possible to install it in a mold.
Numeral 13 denotes a multilayer heat insulating sheet for blocking heat transfer between the inside of the vacuum vessel 10 and the outside. As the heat insulating sheet 13, it is preferable that dozens of Mylar sheets on which Al is vapor-deposited are stacked, whereby the inside of the vacuum vessel can be more appropriately kept at a low temperature.
[0029]
Thus, even when the frequency of the mold is increased, the continuous casting operation at a high speed can be performed without adversely affecting the superconducting coil.
[0030]
By the way, when the continuous casting using the superconducting magnet was operated for a long period of time, a case where the superconducting state of the superconducting coil disappeared occurred.
In other words, when applying the superconducting magnet to the continuous casting method, it is designed so that it can be sufficiently applied to the actual continuous casting machine, and after conducting the actual machine test, it shows that it can be used Despite the fact that it was installed on a real machine, it nevertheless occurred in some cases that the superconducting state could not be maintained.
Therefore, the inventors conducted a detailed investigation in order to elucidate the cause of the disappearance of the above-described superconducting state.
[0031]
That is, a CGR temperature sensor was installed in a superconducting coil inside a superconducting magnet, a low current was applied from the outside, and the temperature was measured by resistance.
As a result, it became clear that the temperature inside the superconducting magnet was not always constant, but changed in a very short cycle.
The results of this investigation are shown in FIGS.
[0032]
FIG. 5 shows the relationship between the CGR resistance value and the temperature of each of the two CGR temperature sensors attached to the superconducting coils inside the two superconducting magnets A and B with the mold interposed therebetween for inspection. FIG. 6 shows the relationship between the elapsed time in the actual continuous casting operation and the CGR resistance value inside the superconducting magnet, measured by the two CGR temperature sensors.
Therefore, the internal temperature of the superconducting magnet can be obtained by converting the resistance value obtained in FIG. 6 to a temperature in FIG.
[0033]
As shown in FIG. 6, since the temperature change of the superconducting coil occurs at a very early stage, it is unlikely that the temperature rise occurs due to normal heat conduction and heat radiation. Moreover, since the cryo (cooling device) of the superconducting magnet has a heat insulating material added to a metal having a thickness of several tens of millimeters, it is unlikely that an external temperature change directly increases the temperature of the superconducting coil.
Then, when the thermocouple was attached to the superconducting magnet and the measurement was performed in more detail, the temperature sometimes rose on a part of the wall surface of the superconducting magnet, particularly on the bottom surface, and the heat input to the superconducting magnet was observed. It was newly found that not only the outside air but also the radiant heat had a great effect.
[0034]
Usually, in the gap between the rolls, there is a nozzle for jetting cooling water to cool the slab, from which cooling water is always jetted and a water curtain is formed, so that radiant heat is shut off Was thought.
However, the above investigation revealed that radiant heat from the gap between the rolls may pass through the water curtain and the water vapor curtain to some extent and reach the superconducting magnet.
[0035]
Therefore, when a superconducting magnet is used as a means for applying a magnetic field to molten steel in a mold of a continuous casting machine, radiant heat from the slab, heat transfer from steam of cooling water sprayed on the slab, radiant heat, etc. It is important to block out.
Such blocking means include:
1) When a heat shield is provided outside the superconducting magnet at a distance from the magnet,
2) There are two cases in which a part or the whole of the outer wall of the superconducting magnet is constituted by a heat shield, but it is only necessary to block radiant heat by either of them.
[0036]
FIG. 7 shows a case where a heat shield is provided outside the superconducting magnet. In the figure, reference numeral 14 denotes a superconductive magnet, and reference numeral 15 denotes a heat shield.
In the example of FIG. 7, the case where the heat shield 15 is provided on the entire outer surface of the superconducting magnet 14 has been described. However, the heat shield 15 does not necessarily need to be provided on the entire outer surface of the superconducting magnet 14. Alternatively, it may be simply installed only on the bottom surface where the influence of radiant heat or heat transfer is greatest.
[0037]
As the heat shield 15, any material that exhibits a heat insulating effect is suitable, and its material and structure are not particularly limited.
a) a structure comprising one or more layers of heat insulating material;
b) a structure having at least its surface made of a substance having a high thermal reflectance;
c) Structures or the like that are cooled internally or externally by a cooling fluid are particularly advantageously suitable.
[0038]
Next, FIG. 8 shows a case where the entire outer wall of the superconducting magnet is formed of a heat shield. Reference numeral 16 in the figure denotes an outer wall formed of the heat shield.
In this case as well, the material and structure of the heat shield are not particularly limited, but the structures a) to c) described above are advantageously adapted similarly to the above case. is there.
[0039]
By the way, when the casting speed decreases, such as at the start or end of continuous casting, or when the casting speed is changed during casting, it is desirable to control the electromagnetic force accordingly. However, when a current flowing through the superconducting coil is changed, a loss called an AC loss occurs in the superconducting conductor. Generally, AC loss is roughly classified into hysteresis loss occurring in a superconducting filament such as NbTi and coupling loss occurring in stabilized copper which is a base material for embedding the superconducting filament. Then, as the change in the speed of the magnetic field increases, any loss increases.
As described above, AC loss does not occur when operating with a constant static magnetic field, but when the static magnetic field is changed (when excited or demagnetized), the magnetic field applied to the superconducting conductor changes. Then, AC loss occurs and the temperature of the conductor rises.
[0040]
Therefore, the inventors have tried various improvements on the structure of the superconducting magnet.
For example, a method of immersing and cooling a superconducting coil directly in liquid helium was also studied. However, in this method, it is necessary to provide a helium cooling channel in the superconducting coil, so that the cross-sectional area of the coil increases and the required conductor length also increases. In addition, in the case of the immersion cooling method, a liquefaction machine is required, so a larger liquefaction / refrigeration device is required compared to the conduction cooling system, and the required number of refrigerators increases and the cooling device becomes huge, It becomes difficult to store the magnet in the restricted space in the continuous casting machine.
In addition, by providing a cooling channel, the coil cannot be integrated with epoxy resin, so the conductor moves by electromagnetic force, the temperature of the conductor rises due to frictional heat at that time, and the superconducting coil transitions to normal conduction (quenching) Problems are more likely to occur.
Therefore, it is difficult to employ the above-described method in applications where the equipment space is greatly restricted and the use conditions are severe as in the continuous casting equipment.
[0041]
Then, the inventors have further devised and found that the above-mentioned problem can be solved by using a conductor having a smaller NbTi filament diameter than the conventional one.
FIG. 9 shows the results of examining the relationship between the diameter of the superconducting wire and the demagnetization time when the diameter of the superconducting wire is variously changed when the conduction cooling system is used. Here, the demagnetization time is the time required to change the magnetic field from 1T to 0.3T.
As shown in the figure, the demagnetization time was significantly reduced by reducing the superconducting wire diameter from 15 μm to 5 μm or less. A particularly preferred wire diameter is 1 μm or less.
It has been confirmed that the relationship between the diameter of the superconducting wire and the degaussing time is similarly established in the case of the exciting time.
[0042]
Therefore, according to the above-described improvement measures, it is possible to effectively suppress the occurrence of AC loss and the rise in the temperature of the conductor. be able to.
[0043]
【Example】
As the continuous casting machine, a vertical bending type continuous casting machine shown in FIG. 10 was used.
In the figure, reference numeral 17 denotes an immersion nozzle, 18 denotes molten steel, 19 denotes a mold powder, and 20 denotes a roll.
The continuous casting conditions are as follows.
・ Nozzle: 2-hole nozzle (discharge hole diameter: 90 mm × 90 mm square)
・ Pouring speed: 3.6 m / min
・ Vertical portion of vertical bending continuous caster: 2.5 m
・ Mold size: 1.50 m (width) x 0.20 m (thickness)
・ Applied magnetic field: 1T
・ Casting steel type:
C: 300 to 350 ppm, Mn: 0.15 to 0.2 mass%, P: 0.025 mass% or less,
S: 0.015 mass% or less, Al: 0.025 to 0.038 mass%, T.S. O. : 25 to 35 ppm
・ Tundish molten steel temperature: 1550-1565 ° C
・ Amount of casting: 300 ton (1 charge)
Method A: the present invention (a method of vibrating a superconducting magnet in synchronization with a mold)
Method B: Conventional method (a method in which a superconducting magnet is fixed and only a mold is vibrated)
Continuous casting was performed by both methods.
Table 1 shows the results of investigation on the stress applied to the mold and the superconducting coil during casting and the maximum internal temperature of the coil.
[0044]
[Table 1]

[0045]
As shown in Table 1, according to the present invention, the load applied to the superconducting coil and the rise in temperature inside the coil, which have conventionally been problems, can be effectively improved, and as a result, the mold frequency increases. This is advantageous in increasing the negative strip rate and reducing the breakout occurrence rate.
[0046]
【The invention's effect】
Thus, according to the present invention, oscillation (mold vibration) at a high frequency becomes possible, and as a result, high-quality slabs can be produced by high-speed continuous casting.
[Brief description of the drawings]
FIG. 1 is a diagram showing the principle of generating a mold reaction force.
FIG. 2 is a diagram showing a support point of a conventional superconducting coil.
FIG. 3 is a plan view (a), a front view (b) and a rear view (c) showing an internal structure of a superconducting coil according to the present invention.
FIG. 4 is a diagram showing a procedure for supporting a superconducting coil with three pull cords.
FIG. 5 is a diagram showing a relationship between resistance and temperature of a CGR temperature sensor attached to a magnet coil.
FIG. 6 is a diagram showing a relationship between an elapsed time in a continuous casting operation measured by two CGR temperature sensors and a CGR measurement value inside a magnet.
FIG. 7 is an explanatory diagram of a state where a heat shield is installed on a superconducting magnet.
FIG. 8 is an explanatory diagram in the case where the entire outer wall of the superconducting magnet is constituted by a heat shield.
FIG. 9 is a graph showing the relationship between the wire diameter and the demagnetization time when the wire diameter of the superconducting wire (NbTi filament) is variously changed.
FIG. 10 is a schematic view of a continuous casting machine to which the present invention is applied.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 mold 2 superconducting magnet coil 3 magnetic field 4 induced current 5 mold reaction force 6 support material 7 coil case 8 horizontal cable 9 pull cable 10 vacuum vessel 11 refrigerator 12 metal plate 13 heat insulating sheet 14 superconducting magnet 15 heat shield 16 Outer wall composed of heat shield 17 Dipping nozzle 18 Molten steel 19 Mold powder 20 Roll

Claims (5)

A magnetic field generator for generating a static magnetic field in a direction opposite to a long side wall of a continuous casting mold, comprising an annular air-core superconducting coil, a coil case for fixing the coil, and a vacuum for the coil case. A plurality of cords to be locked at predetermined positions in the container, a refrigerator connected to the superconducting coil via a metal connector, and a coil for keeping the coil at an extremely low temperature by conduction cooling; Equipped with a vacuum device that controls the decompression of
A magnetic field generator for continuous casting of steel, wherein the coil case is supported from the back by horizontal ropes having a double cylindrical structure, and supported by at least three pulling ropes from above and below. 2. The magnetic field generator for continuous casting of steel according to claim 1, wherein the coil case is supported from above and below by at least three pull cords on the back side of the coil case. The magnetic field generator for continuous casting of steel according to claim 1 or 2, further comprising a heat shield provided outside the magnetic field generator to block radiant heat from the slab. The steel according to claim 1, 2, or 3, wherein an NbTi superconducting wire having a wire diameter of 5 µm or less is wound in a race track shape, and after winding, the coil is integrated by vacuum impregnation with epoxy resin. Magnetic field generator for continuous casting. When performing continuous casting of steel using a continuous casting mold provided with the magnetic field generating device according to any one of claims 1 to 4, while synchronously oscillating the mold and the magnetic field generating device, from the magnetic field generating device A continuous casting method for steel, wherein the flow of molten steel in a mold is controlled by using the generated strong static magnetic field.

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