JPH09295111A - Continuous casting method for steel using static magnetic field - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To extend the number of charges used for an immersion nozzle used in continuous casting. SOLUTION: In performing continuous casting of a slab while supplying molten steel in a tundish into a continuous casting mold composed of a pair of short side walls and long side walls through an immersion nozzle connected to the tundish, As a soaking nozzle connected to the tundish, a single hole nozzle made of a composite material that does not easily deposit inclusions at the tip of the nozzle or the inner and outer surfaces of the nozzle is used. Apply a static magnetic field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous casting method for steel, which significantly improves the surface and internal quality of a slab obtained by continuous casting of steel and enables high speed casting.

[0002]

2. Description of the Related Art Conventionally, in continuous casting of slabs used for manufacturing wide steel sheets, a refractory immersion nozzle is usually used as a molten steel flow path between a tundish containing molten steel and a continuous casting mold. Has been done. This dipping nozzle has a problem that the molten steel flow passage is narrowed with the elapse of casting time and the desired molten steel flow rate cannot be obtained because alumina easily adheres to the inner surface of the nozzle during continuous casting of aluminum-killed steel. It was

The adhesion of alumina on the inner surface of the nozzle is especially 2
Since it is likely to occur in multi-hole nozzles such as holes and four holes and the use of these multi-hole nozzles is indispensable in high throughput slab casting, it was necessary to solve this problem early.

Regarding this point, an attempt has been made to cope with this by supplying an inert gas such as argon into the nozzle during the supply of molten steel, but in the multi-hole nozzle, it descends vertically. Since the molten steel flow is greatly bent in the direction of the short piece of the mold at the nozzle outlet, a negative pressure is generated at the top of the outlet, and inclusions accumulate there, gradually causing nozzle clogging. It was very difficult to make a charge.

When the flow rate of molten steel is high and the throughput is high, the inert gas blown into the nozzle is entrained in the steel flow having a high flow rate and cannot float above the molten metal in the mold. In some cases, the gas was trapped in the solidified shell and, after cold rolling, blistering defects caused by the gas were generated.

Further, as shown in FIGS. 1 (a), (b), and (c), in a two-hole type immersion nozzle having a symmetrical nozzle discharge port a at the tip of the nozzle, the nozzle discharge port 1 There was a problem that asymmetric flow was generated due to asymmetrical left and right blockages, resulting in deterioration of coil quality.

As a problem of quality deterioration caused by the nozzle clogging, not only the multi-connection due to the nozzle clogging is not achieved, but also the defect is caused by the gas trapped in the solidification shell and the nozzle discharge port a is clogged. There was also the occurrence of defects due to inclusion of inclusions and mold powder due to uneven flow.

As an attempt to solve such a problem, Japanese Laid-Open Patent Publication No. 60-92064 discloses a nozzle blockage by applying a dc magnetic field to the molten metal flow in the immersion nozzle to make the molten metal flow laminar. Although a method of injecting molten metal to suppress the above is disclosed, in the method disclosed herein, since the molten metal flow flows down deep inside the molten metal crater in the mold, it is possible to float the accompanying inclusions. There was a risk that it could not be trapped in the solidified shell.

Further, in Japanese Patent Laid-Open No. 62-3857,
A technique of applying a static magnetic field to a region of a straight nozzle to form a molten steel discharge flow is disclosed, but this technique cannot sufficiently obtain the effect of the static magnetic field, and a slab having a quality comparable to that of a conventional porous nozzle is provided. There was enough room for improvement as far as it was obtained.

A combination of a two-hole nozzle and a two-stage static magnetic field is disclosed in Japanese Patent Laid-Open No. 2-284750, but the quality is still insufficient.

Further, Japanese Unexamined Patent Publication No. 7-50801 or Japanese Unexamined Patent Publication No. 7-51802 discloses a method for producing a clad steel by using a single hole straight nozzle and applying a static magnetic field to the lower end of the mold. There is.

[0012] These methods are methods for producing clad steel with good accuracy and at low cost, and it was thought that the problems such as nozzle clogging and drift in the past can be solved by this method. However, in these methods, since the molten steel is disturbed on the surface of the mold, although it can be experimentally manufactured, it is difficult to perform the process manufacturing in which quality and cost are important.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to propose a continuous casting method which can solve the above-mentioned conventional problems in continuous casting of steel and can obtain a slab having good surface and internal quality. .

In particular, in order to achieve the above object, it is necessary that the molten steel discharged from the dipping nozzle is made to have a uniform downward flow in the mold at an early stage. In the present invention, nozzle clogging and drift of molten steel in the mold are caused. It is possible to control the flow of molten steel in the vicinity of the discharge port of the immersion nozzle and to control the uniform flow of molten steel in the mold without disturbing the meniscus.

[0015]

In the present invention, various experiments and studies were conducted on nozzle clogging during continuous casting using aluminum killed aluminum deoxidized with a carbon concentration of 500 ppm or less. As a result, using a straight nozzle that releases the tip of the immersion nozzle body that supplies molten steel from the tundish into the mold and uses it as the molten steel discharge port,
We found that there was almost no nozzle clogging.

Further, it was also clarified that the turbulence of the molten metal surface becomes extremely small because the discharge flow is all directed downward. However, in such a straight nozzle, the discharge velocity of the molten steel is directed to the outlet side (downward) of the mold, so that inclusions and bubbles in the molten steel may penetrate deep into the crater.

To solve such a problem, Japanese Unexamined Patent Publication No.
As disclosed in Japanese Patent No. 293620, it is very effective to apply a static magnetic field parallel to the short side wall constituting the mold in the vicinity of the discharge nozzle of the immersion nozzle or below the discharge nozzle. As a result, it has become possible to completely eliminate the clogging and drift of the nozzle, which has been a problem so far, and prevent the intrusion of inclusions and bubbles.

However, when performing multiple casting in which the number of charges is further increased as compared with the conventional case, there is a problem that inclusions adhere to the tip of the immersion nozzle. Figure 1 shows Table 1
Fig. 2 is a sketch of the appearance and cross section of a straight nozzle when a steel having the composition shown in Fig. (Steel type: extremely low carbon steel for automobiles) is continuously cast for 8 charges.

[0019]

[Table 1]

As shown in FIG. 2, the inner surface of the straight nozzle is not clogged by inclusions, but the inclusion of inclusions is generated at the tip of the nozzle. This depends on the type of steel, but from 7 charges to 8 charges. It is newly revealed that it starts to occur at the charge eye.

[0021] This problem was a problem that did not exist at all at the time of using an early straight nozzle when a continuous casting method was developed, and its existence becomes clear only by casting using a straight nozzle and a static magnetic field. When the continuous casting is continuously performed for 7 to 8 charges, the immersion nozzle tip portion has a larger number, and when the nozzle tip tip deposit has grown, inclusions have grown. It is possible that the solidified shell or the solidified shell comes into contact with the slab.In that case, the inclusion lumps enter the slab and become waste, and in the worst case, the inclusion and the solidified shell are fixed and the shell cannot be pulled out. There was a risk of breakage and breakout.

The present invention intends to solve the above-mentioned problems newly caused in addition to the above-mentioned problems by the following means. That is, the invention of this application provides continuous molten slabs while supplying molten steel in a tundish into a continuous casting mold consisting of a pair of short side walls and long side walls through an immersion nozzle connected to the tundish. In casting, a single-hole nozzle made of a composite material with which inclusions are hard to adhere to the tip of the nozzle or the inner and outer surfaces of the nozzle is used as the immersion nozzle connected to the tundish. It is a continuous steel casting method using a static magnetic field, characterized in that a static magnetic field is continuously applied between the two.

In the continuous casting method having the above structure, the static magnetic field is preferably applied in the vicinity of the nozzle discharge port of the immersion nozzle or below the discharge port. In this case,
The static magnetic field may be further applied below the region to which the static magnetic field is applied.

In applying the static magnetic field, it is advantageous according to the present invention that the long side walls of the mold are extended in the vicinity of the meniscus.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 3 (a) and 3 (b) show the structure of the main part of a continuous casting apparatus suitable for carrying out the present invention. Reference numeral 1 in the figure indicates a pair of short side wall 1a and long side wall 1
The continuous casting mold 2 consisting of b is a straight submerged nozzle which is made of a composite material using a material with which inclusions are unlikely to adhere to the tip of the nozzle or the inner and outer surfaces of the nozzle, and the rear end of which is connected to the tundish. The straight immersion nozzle 2 has a discharge port 2a in which the tip of the nozzle body is opened.

Further, 3 is arranged on the back surface of the long side wall 1b of the continuous casting mold 1, and also includes the straight immersion nozzle 2 and the meniscus, and a static magnetic field from the long side wall 1b to the other long side wall 1b. In the static magnetic field generator, the static magnetic field generated by the static magnetic field generator 3 decelerates the molten steel discharged from the straight immersion nozzle 2 and suppresses the fluctuation of the molten metal surface to prevent the entrainment of powder.

Reference numeral 4 denotes a static magnetic field generator disposed below the static magnetic field generator 3 with a region c therebetween, and the molten steel decelerated by the static magnetic field generated by the static magnetic field generator 3 has a region close to no magnetic field. In c, the flow becomes almost uniform, and the molten steel is further decelerated by the static magnetic field generated by the static magnetic field generator 4. As a result, the molten steel is sufficiently decelerated and becomes a uniform downward flow.

FIGS. 4 (a) (b) (c) show a straight immersion nozzle suitable for carrying out the present invention, and FIG. 5 shows a conventional type straight immersion nozzle.
In this invention, as shown in FIGS. 4 (a) (b) (c), CaO.ZrO _{2 is used} as an example to prevent the inclusion of inclusions at the nozzle tip.
Use a dipping nozzle that applies the material.

With the material shown in FIG. 4 above, a sufficient effect can be expected if it is applied only to the tip portion, but CaO may be applied to a part of the inner surface of the nozzle tip or a part of the outer surface or both. -When a ZrO ₂ material is used, its effect is further improved.

In the two-hole type immersion nozzle already shown in FIG. 1, alumina or the like is liable to adhere particularly near the discharge port to cause nozzle clogging. However, the straight immersion nozzle according to the present invention is used to remove molten steel in the tundish. When it is supplied into a casting mold for continuous casting to which a static magnetic field is applied, the molten metal surface is calmed down, and it is possible to carry out continuous casting with a uniform downward flow without causing nozzle clogging due to alumina adhesion. It does not penetrate deep into the crater, nor does the rising flow of molten steel entrain the powder on the bath surface. What is more important is that the adhesion of inclusions at the tip of the straight nozzle, which is a newly revealed problem in conventional static magnetic field application and casting with a straight nozzle, has been significantly reduced, resulting in the realization of multi-continuous casting. Will be possible.

[0031]

【Example】

Example 1 Using a two-strand continuous casting machine, continuous casting of low carbon aluminum killed steel having an oxygen concentration of 28 to 35 ppm was performed continuously for 8 charges. The casting conditions at this time are as follows.

Blowing amount of gas for preventing nozzle clogging: 12Nl / min Size of casting mold: 260mm in thickness direction, 1500mm in width direction, 800mm in height direction Superheat of molten steel in tundish: 29 to 34 ° C Throughput: 4.5 ton / min

In one of the two strands, a straight dipping nozzle is used to apply a static magnetic field in one stage for casting, and in the other strand, a static magnetic field is not applied and a two-hole dipping nozzle is used. Then, continuous casting was performed. 6 (a) and 6 (b) show the arrangement of the static magnetic field generators by broken lines, and their specifications are shown below.

Specifications of static magnetic field generator 1-stage type Width dimension: 1700 mm Height dimension: 50 to 650 mm (L) Maximum magnetic flux density: 0.3 T

During continuous casting, casting was performed while controlling the flow rate of molten steel with a sliding nozzle and confirming nozzle blockage. As a result, when a two-hole type immersion nozzle was used as shown in FIG. Nozzle blockage had already occurred at the continuous line, and it was necessary to replace the nozzle. However, in continuous casting according to the present invention, as shown in FIG. I couldn't do it.

Next, continuous casting according to the present invention (using a straight immersion nozzle made of CaO.ZrO ₂ and applying a static magnetic field in one step) according to the present invention is performed on one strand, and normal continuous casting (CaO. A straight immersion nozzle without ZrO ₂ was used to apply a static magnetic field in one step), and nozzle clogging was investigated. In all cases, no nozzle clogging was observed at the stage when the 8-casting was completed. In the conventional straight immersion nozzle, inclusions have begun to adhere to the tip of the nozzle as shown in FIG.

Example 2 Next, a second example equipped with a generator capable of moving a static magnetic field was used.
Using a continuous strand casting machine, straight dipping nozzle + static magnetic field, 2-hole dipping nozzle + static magnetic field, oxygen concentration of 23 ~
Continuous casting of ultra-low carbon aluminized steel of 30ppm was carried out continuously for 8 charges under the following conditions.

Casting conditions Gas blow-in amount for preventing nozzle clogging: 14 Nl / min Size of continuous casting mold: 220 mm in thickness direction, 1600 mm in width direction, 800 mm in height direction Superheat of molten steel in tundish : 20-24 ℃ Throughput: 4.0 ton / min

In one strand of the two-strand continuous casting machine, continuous casting according to the present invention was carried out (a straight dipping nozzle was used and the tip of the discharge port was
A static magnetic field of a stage was applied), and a two-hole type immersion nozzle was used for the other strand, and continuous casting was performed while applying a static magnetic field to two locations at the lower end.

10 (a) and 10 (b) show the arrangement of the static magnetic field generator. As the static magnetic field generator, one having a magnetic pole size of 500 mm in the width direction and 200 to 250 mm in the height direction and a maximum magnetic flux density of 0.3 T was used.

During continuous casting, casting was carried out while confirming nozzle clogging by sliding for controlling molten steel flow. When a two-hole type immersion nozzle was used, it was possible to obtain 4 stations even if a static magnetic field was applied. Nozzle clogging occurred and it was necessary to replace the nozzle. However, in the case where continuous casting was performed according to the present invention, nozzle clogging was of course caused by the continuous charging of 8 charges, and the inclusion of inclusions at the nozzle tip. Was not seen.

Next, in one strand, CaO.ZrO ₂
Continuous casting with a static magnetic field applied to the other strand using a straight dipping nozzle consisting of, and one strand using a normal straight dipping nozzle (without using CaO / ZrO ₂ ) on the other strand Continuous casting was carried out by applying a static magnetic field. As a result, in any case, no nozzle blockage was observed even when casting was continuously performed for 8 charges, but inclusions were adhering to the nozzle tip portion in continuous casting using a conventional straight immersion nozzle.

Example 3 Next, using a two-strand continuous casting machine equipped with a static magnetic field generator capable of moving a static magnetic field, a straight immersion nozzle + static magnetic field, a two-hole type immersion nozzle + oxygen concentration as a static magnetic field. But
Continuous casting of ultra low carbon aluminum killed steel of 25 to 33 ppm was performed continuously for 8 charges under the following conditions.

Casting conditions Gas blow-in amount for preventing nozzle clogging: 14 to 16 Nl / min Size of casting mold: Thickness direction dimension 220 mm, Width direction dimension 1500 mm Height direction dimension 800 mm Superheat of molten steel in tundish : 21-25 ℃ Throughput: 3.9 ton / min

In one strand of the two-strand continuous casting machine, continuous casting according to the present invention is carried out (a straight immersion nozzle is used and a static magnetic field of one stage is applied to its lower end without including a discharge port). For one strand, a two-hole type immersion nozzle was used, and continuous casting was performed while applying a static magnetic field to the two locations at the lower end.

FIGS. 11 (a) and 11 (b) are views showing the arrangement of the static magnetic field generator. As for the static magnetic field generator, the dimensions of the magnetic poles are 500 mm in the width direction and 200 to 200 mm in the height direction. 250 mm
The maximum magnetic flux density used was 0.05 to 0.5 T.

During continuous casting, casting was performed while confirming nozzle clogging by sliding for controlling molten steel flow. When a two-hole type immersion nozzle was used, 4 charges were applied even if a static magnetic field was applied. The nozzle was already clogged with the eyes, and it was necessary to replace the nozzle. However, when continuous casting was performed according to the present invention, the nozzle was not clogged even at the 8th charge, and inclusions at the tip of the nozzle did not occur. No adhesion was observed.

Then, in one strand, CaO.ZrO ₂
Continuous casting with a static magnetic field applied to the other strand using a straight dipping nozzle consisting of, and one strand using a normal straight dipping nozzle (without using CaO / ZrO ₂ ) on the other strand Continuous casting was carried out by applying a static magnetic field. As a result, in any case, no nozzle clogging was observed even when casting was performed continuously for 8 charges, but when a conventional straight immersion nozzle was used, inclusions began to adhere to the nozzle tip.

Example 4 While applying a static magnetic field at the meniscus portion of the continuous casting mold and the lower end of the nozzle of the straight dipping nozzle, an ultra low carbon aluminum killed steel having an oxygen concentration of 25 to 35 ppm was continuously charged for 8 charges under the following conditions. And cast.

Casting conditions Gas blow-in amount for preventing nozzle clogging: 13 to 16 Nl / min Size of casting mold: Thickness-direction dimension 260 mm, width-direction dimension 1600 mm Height-direction dimension 800 mm Superheat of molten steel in tundish: 20 ~ 26 ℃ Throughput: 4.8 ton / min

Then, in one strand of the two-strand continuous casting machine, continuous casting according to the present invention is performed (a straight nozzle is used and a static magnetic field is applied to the lower side of the nozzle outlet and the meniscus portion), and the other is cast. For the strand, casting was performed by using a conventionally used straight dipping nozzle and applying the same two-stage static magnetic field as above.

FIGS. 12 (a) and 12 (b) are views showing the arrangement of static magnetic field generators. As a static magnetic field generator arranged in the meniscus, the size of the magnetic pole is 1700 mm in the width direction and 200 to 250 mm in the height direction, and the maximum magnetic flux density is 0.05 to 0.
For a static magnetic field generator arranged below the nozzle outlet, the size of the magnetic pole is 500 in the width direction.
The maximum magnetic flux density is 0.05 to 0.5 T, and the maximum magnetic flux density is 200 to 250 mm in the height direction.

During continuous casting, casting was performed while confirming nozzle clogging by sliding for controlling molten steel flow. As a result, nozzle clogging did not occur even if casting was continuously performed for 8 charges in each case. In the conventional straight nozzle, inclusions started to be generated at the tip of the nozzle.

Regarding the quality of the two-strand coil, the defects produced in the cold-rolled material were observed. As shown in FIG. 13, when the continuous casting was carried out according to the present invention, the coil quality was higher than that of the ordinary continuous casting. It was revealed that the defect generation rate (the coil defect generation index is an average of the defect positions divided by the length of the entire coil, where the defect position is 1 m) is low.

Example 5 A static magnetic field was applied to the meniscus portion of a continuous casting mold, and a static magnetic field was applied over the entire width of the lower end of the nozzle outlet of a straight immersion nozzle to obtain an oxygen concentration of 25 to 35 ppm, an extremely low carbon aluminum killed steel. Was continuously cast for 8 charges under the following conditions.

Gas injection amount for preventing nozzle clogging: 13 to 16 Nl / min Size of casting mold: thickness dimension 260 mm, width dimension 1600 mm height dimension 800 mm Superheat of molten steel in tundish: 20 to 27 ℃ throughput: 4.8 ton / min

In one strand of the two-strand continuous casting machine, continuous casting according to the present invention was performed (a straight dipping nozzle was used to apply a static magnetic field to the lower side of the nozzle outlet and the meniscus portion), and the other was cast. For the strand, casting was performed by using a conventionally used straight dipping nozzle and applying a two-stage static magnetic field as described above.

FIGS. 14 (a) and 14 (b) show the arrangement of the static magnetic field generator. The static magnetic field generator placed in the meniscus has a pole size of 1700 mm in the width direction and 200 to 250 mm in the height direction, and the maximum magnetic flux density is 0.05 to 0.5 T.
As a static magnetic field generator arranged below the nozzle discharge port, the size of the magnetic pole is 1700 mm in the width direction,
The maximum magnetic flux density is 200-250 mm in the height direction.
The thing used becomes 0.05-0.5T.

During continuous casting, casting was performed while confirming nozzle clogging by sliding for controlling molten steel flow.
As a result, in any case, the nozzle was not clogged even at the end of the 8th charge, but in the conventional straight immersion nozzle, inclusions started to be generated at the tip of the nozzle.

Regarding the coil quality of the two strands, the defects generated in the cold rolled material were observed, and as shown in FIG.
It has been clarified that in the case where the continuous casting according to the present invention is performed, the defect occurrence rate of the coil is lower than that in the case where the normal continuous casting is performed.

In the above embodiment, the static magnetic field applied at the lower end of the nozzle discharge port is all one step, but it can be set to multiple steps, and in this case, further improvement effect can be expected. Needless to say.

In the vicinity of the meniscus portion, it is important to generate a static magnetic field so as to cover the entire molten metal surface. For example, if the static magnetic field does not reach the molten steel surface and acts only on the lower surface of the molten steel, it is possible to suppress the vibration of the molten steel surface even if the flow below the molten surface can be damped. This is because it is not possible to involve the mold powder on the molten metal surface due to the vibration of the molten metal surface.

In the present invention, the static magnetic field plays a particularly important role, but it is important to set the magnetic field application region as follows. First, the static magnetic field is applied at the lower side of the nozzle tip or below the nozzle tip. Especially, if the discharge port at the tip of the nozzle is kept in the magnetic field, the molten steel discharge flow becomes a gentle downward flow that is sufficiently decelerated by the static magnetic field. Further, in the present invention, the nozzle tip portion is described as being made of CaO.ZrO _2. However, the present invention is not limited to this and may be any material that is expected to have the effect of preventing inclusions from inclusions.

[0064]

As described above, according to the present invention, stable continuous casting is possible and product quality and productivity can be improved. In particular, it has become possible to dramatically increase the number of charges used by the immersion nozzle as compared with conventional continuous casting.

Further, by making the region to which the static magnetic field is applied in multiple stages, the molten steel flow can be made more uniform, and a continuous casting slab of high quality which has not been obtained in the past can be obtained.

When the oxygen concentration of the molten steel is low, it is not necessary to blow in a gas for preventing nozzle clogging, so that quality defects due to such gas can be avoided.

[Brief description of drawings]

1A and 1B are views showing a structure of a two-hole type immersion nozzle.

FIG. 2 is a view showing the appearance and cross section of a conventional straight immersion nozzle.

FIGS. 3 (a) and 3 (b) are views showing the configuration of the main part of a casting apparatus suitable for use in the practice of the present invention.

4 (a), (b) and (c) are views showing immersion nozzles suitable for carrying out the present invention.

FIG. 5 is a view showing a conventional straight nozzle.

6 (a) and 6 (b) are diagrams showing the arrangement of static magnetic field generators.

FIG. 7 is a diagram showing a closed state of a nozzle.

FIG. 8 is a diagram showing a situation of a tip end portion of a nozzle used in implementing the present invention.

FIG. 9 is a view showing a situation of a nozzle tip in continuous casting using a conventional immersion nozzle.

FIG. 10 (a) is a diagram showing a situation when performing continuous casting according to the present invention, and (b) is a diagram showing a situation when performing continuous casting according to a conventional method.

FIG. 11 (a) is a diagram showing a situation when performing continuous casting according to the present invention, and (b) is a diagram showing a situation when performing continuous casting according to a conventional method.

FIG. 12 (a) is a diagram showing a situation when continuous casting is performed according to the present invention, and (b) is a diagram showing a situation when continuous casting is performed according to a conventional method.

FIG. 13 is a diagram showing a result of investigating a coil defect occurrence rate.

FIG. 14 (a) is a diagram showing a situation when continuous casting is performed according to the present invention, and (b) is a diagram showing a situation when continuous casting is performed according to a conventional method.

FIG. 15 is a diagram showing a result of investigating a coil defect occurrence rate.

[Explanation of symbols]

 1 Continuous casting mold 2 Immersion nozzle 3 Static magnetic field generator 4 Static magnetic field generator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Fujii, 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Technical Research Institute, Kawasaki Steel Co., Ltd. Steel Works Co., Ltd. Chiba Steel Works (72) Inventor Katsuoka Katsuhiko 1 Kawasaki-cho, Chuo-ku, Chiba, Chiba Prefecture Kawasaki Steel Works Chiba Works (72) Inventor Yoshihisa Kitano Kawasaki-cho, Chuo-ku, Chiba City Chiba Steel Works, Ltd.

Claims (6)

[Claims] 1. When performing continuous casting of a slab while supplying molten steel in a tundish into a continuous casting mold consisting of a pair of short side walls and long side walls through an immersion nozzle connected to the tundish. As a dipping nozzle connected to a tundish, a single-hole nozzle made of a composite material that does not easily deposit inclusions at the tip of the nozzle or the inner and outer surfaces of the nozzle is used. A method for continuously casting steel using a static magnetic field, which comprises applying a static magnetic field. 2. The continuous casting method according to claim 1, wherein a static magnetic field is applied in the vicinity of the nozzle discharge port of the immersion nozzle. 3. The continuous casting method according to claim 1, wherein the static magnetic field is applied below the nozzle discharge port of the immersion nozzle. 4. The continuous casting method according to claim 2, wherein the static magnetic field is further applied between the long side walls of the mold below the region to which the static magnetic field is applied. 5. The continuous casting method according to claim 1, wherein a static magnetic field is applied between the long side walls of the mold in the vicinity of the meniscus. 6. The continuous casting method according to claim 1, wherein a static magnetic field is applied to the entire area of the long side wall of the continuous casting mold in the width direction.