JP2986361B2 - Electromagnetic short side weir of twin roll type continuous sheet casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic short side weir for holding molten metal at both ends of a mold roll in a twin-roll type continuous sheet casting apparatus for continuously drawing a thin sheet between mold rolls arranged in parallel with each other. About.

[0002]

2. Description of the Related Art Conventionally, in order to hold a supplied molten metal, a short side weir slidably contacting both end surfaces is conventionally arranged on a mold roll. However, since the molten metal and the short side weir are in physical contact with each other, There have been problems such as the sliding contact between the end face of the mold roll and the short side dam being damaged, and the end face of the cast piece being damaged, thereby lowering the product yield.

For this reason, Japanese Patent Application Laid-Open No. Hei 6-503035 states that
2. Description of the Related Art Electromagnetic short side dams that hold a molten metal in a non-contact manner by using an electromagnetic force have been proposed.

[0004]

As shown in FIGS. 9 to 11, the electromagnetic short side weir extends a rib r around the end of the mold roll R and a predetermined position on the back side of the rib r. The magnetic poles M are respectively arranged, and an alternating magnetic flux m formed between the magnetic poles M is passed through the molten metal S via the rib r, and an electromagnetic force (electromagnetic pressure) generated by the alternating magnetic flux m
Is caused to act in the direction in which the molten metal S leaks out, and the molten metal S is held.

As shown in FIG. 12, the pressure P required to hold the molten metal at this time is a dynamic pressure generated by the static pressure Ph determined by the height h of the molten metal S and the flow pressure from the tundish nozzle. And the pressure Pv.

P = Ph + Pv Here, the static pressure Ph of the molten metal M increases linearly as the height h from the surface increases, and becomes maximum at the kiss portion K where the mold rolls R and R come closest.

Ph = ρg (H−h) H: Maximum height of the molten metal, ρ: Density of the molten metal, g: Gravitational acceleration On the other hand, the electromagnetic pressure Pm generated by the magnetic flux density B of the alternating magnetic field is Pm = B ² / 2 μ ₀ μ ₀ : magnetic permeability in vacuum, and Pm ≧ P... At all heights h in order to hold the molten metal S.

By the way, in the above conventional example, the left and right magnetic poles M
Are arranged along the outer periphery of the mold roll R, so that the alternating magnetic flux m passes through the rib r and the molten metal S.
The distance Lg between the magnetic poles is set, and the magnetic flux density B is generally inversely proportional to the distance Lg between the magnetic poles.
It becomes as shown in. That is, as the height h from the kiss portion K increases, the distance Lg between the magnetic poles increases, the magnetic flux density B decreases, and the electromagnetic pressure Pm decreases.
For example, when the depth (height) H of the molten metal is 400 mm in a mold roll R having a diameter of 1200 mm, if the formula is set so as to satisfy the equation, the holding pressure P and the electromagnetic pressure Pm become closest at h = 150 to 300 mm, As a result, an excess pressure Pm 'is generated in the kiss portion K.

Therefore, according to the above conventional configuration, h =
When the electromagnetic pressure Pm is set so as to satisfy the equation at 150 to 300 mm, there is a problem that the rib r is overheated by the excessive alternating magnetic flux particularly at the kiss portion K when the mold roll R is made of a ferromagnetic material. When the rib r is overheated, cooling at the end of the slab is not sufficiently performed, and the end of the slab that has exited the kiss portion K expands due to the static pressure Ph of the molten metal S, or the slab easily adheres to the rib, Casting may not be performed normally.

In the above-described embodiment, as a means for solving the above-mentioned problem, a magnetic pole is divided into three parts, and a magnetic element is provided for each of the three parts to adjust the electromagnetic pressure. And there is a problem that the cost increases.

The present invention solves the above-mentioned problems, and can form a proper alternating magnetic flux at the end of the molten metal with a simple structure, thereby obtaining a proper electromagnetic pressure capable of holding the molten metal.
It is an object of the present invention to provide an electromagnetic short side weir of a twin-roll type thin plate continuous casting facility capable of preventing overheating of a ferromagnetic mold roll end without forming an excessive alternating magnetic flux.

[0012]

In order to solve the above problems, a first means according to the present invention is to supply molten metal between a pair of ferromagnetic mold rolls arranged in parallel with each other, By rotating these mold rolls in the relative direction to sandwich the molten metal, the slab shell formed on the surface of the mold roll is pressed and the slab is continuously drawn from the closest part of the mold roll to produce a thin plate. An electromagnetic short side weir of a roll-type thin plate continuous casting facility, wherein a pair of magnetic poles provided at an end of a magnet core are arranged along an outer peripheral portion, facing a mold roll end surface at a portion for holding molten metal, respectively. A shield material made of a diamagnetic material and a paramagnetic material is disposed between the magnetic poles so that the alternating magnetic flux passes through the molten metal from the end of the mold roll. The distance from the magnetic pole to the end face of the mold roll is increased on the closest side of the mold roll so as to form a magnetic field that generates an electromagnetic pressure corresponding to the pressure at which the molten metal can be held according to the level of the molten metal. It is set as follows.

[0013] The second means is to form a pair of magnetic poles provided at the end of the magnet core along a peripheral portion of the mold roll at a portion for holding the molten metal and at a constant gap on the end face of the mold roll. Along with the arrangement, a shielding material made of a diamagnetic material is arranged between these magnetic poles so that the alternating magnetic flux passes through the molten metal from the end of the mold roll, and in the gap between each magnetic pole and the end face of the mold roll, A pair of magnetic adjusting plates capable of adjusting the magnetic flux density formed in the molten metal are arranged.

A third means is that, in addition to the first means, a pair of magnetic adjustment plates capable of adjusting the magnetic flux density of the molten metal at the end is disposed in the gap between each magnetic pole and the end face of the mold roll. is there.

Further, the fourth means is provided with, in addition to the second or third means, a magnetic adjustment device for moving a pair of magnetic adjustment plates toward and away from each other.

[0016]

According to the first configuration, the shield material is arranged between the magnetic poles, so that all the alternating magnetic fluxes are diverted to the mold roll side to pass through the mold roll and the molten metal. The molten metal can be held at the target pressure, the ribs required at the edge of the mold roll can be eliminated, and the magnetic flux density is controlled by adjusting the distance between the magnetic pole and the mold roll. Can be approximated to the pressure required to hold the molten metal, and with a very simple configuration, it is possible to prevent the ferromagnetic mold roll from being overheated due to excessive alternating magnetic flux. In the closest part of the mold roll having a high magnetic flux density, the mold roll and the magnetic pole are separated from each other, so that the magnetic pole can be easily cooled and damage at the time of breakout can be reduced.

According to the second configuration, the magnetic adjustment plate is disposed in the gap between the magnetic pole and the end face of the mold roll, and the alternating magnetic flux is passed through the magnetic adjustment plate made of a ferromagnetic material or a paramagnetic material to thereby reduce the magnetic field. The electromagnetic pressure generated by the alternating magnetic flux is reduced by reducing the excess magnetic flux at the kiss portion by reducing the alternating magnetic flux by halving by shielding or weakening the alternating magnetic flux by a magnetic adjustment plate made of a diamagnetic material. And the mold roll can be prevented from overheating.

Further, by combining the first and second configurations, the control range of the alternating magnetic flux can be further expanded. Furthermore, in response to changes in casting conditions such as slab thickness, casting speed, and level of the molten metal, the magnetic adjustment device moves the magnetic adjustment plate closer and further away to adjust the alternating magnetic flux that passes, thereby generating excess alternating magnetic flux. Can be prevented beforehand, and overheating of the mold roll can be prevented beforehand.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of an electromagnetic short side weir of a twin roll type continuous sheet casting facility according to the present invention will be described with reference to FIGS.

As shown in FIG. 1 to FIG. 5, for example, a steel member having a cooling function built in
A pair of electromagnetic short side weirs 2 according to the present invention on both end surfaces of a pair of left and right mold rolls 1 and 1 made of a ferromagnetic material coated with Cr;
Are arranged, and a mold receiver 3 for holding molten steel is formed by the mold rolls 1 and 1 and the electromagnetic short side weir 2. In this electromagnetic short side weir 2, magnetic poles 5, 5 are provided at both ends of an opening of a magnet core 4 having a U-shaped cross section in a plan view, and a magnet coil 6 is mounted on the opposite side of the opening. The portion is covered with an electromagnetic shield cover 7. A diamagnetic and paramagnetic metal material, for example, a copper shielding material 8 is interposed between the magnetic poles 5 and 5, and an alternating magnetic flux m generated between the magnetic poles 5 and 5 is guided to the mold roll 1 side. It is configured as follows.

The magnetic pole 4 is formed in an arc shape corresponding to the molten steel receiver 3 along the outer periphery of the mold roll 1 and alternately generates an electromagnetic pressure Pm similar to the pressure P required to hold the molten metal in FIG. The side surface of the magnetic pole 5 is formed in a convex curved surface so that the magnetic flux m is obtained, and the distance L between the end face 1a of the mold roll 1 and the magnetic pole 5 is set.

For example, the diameter D of the mold roll 1 is 1
In the case of 200 mm and the height H of the molten metal surface is 400 mm, the kiss point (closest part) 9 where the mold rolls 1 and 1 come closest.
If the distance L2 in the height range of 150 to 300 mm is the closest and about 10 mm, the distance L1 near the molten metal surface SL is about 15 mm, and the distance L3 of the kiss point 9 is about 25 mm
The shape of the magnetic pole 5 is formed so as to be approximately the same.

According to the above embodiment, by disposing the shield material 8 between the magnetic poles 5, all the alternating magnetic fluxes m are diverted to the mold roll 1 side and passed through the mold roll 1 and the molten metal S. The rib provided on the edge of the mold roll can be eliminated. In addition, the shape of the magnetic pole 5 is arbitrarily formed, and the distance L between the magnetic pole 5 and the mold roll 1 is changed.
By adjusting (L1 to L3), the magnetic flux density formed on the mold roll 1 side is controlled to bring the electromagnetic pressure generated by the alternating magnetic flux m closer to the pressure required for holding the molten metal S, thereby making the excess alternating magnetic flux Can be prevented, and the end of the mold roll 1 can be prevented from being overheated with a very simple configuration. Further, the kiss portion 9 of the mold roll 1 has a large distance L between the mold roll 1 and the magnetic pole 5.
As a result, the cooling device for the magnetic pole 5 can be easily added, and damage at the time of breakout can be reduced.

FIGS. 6 and 7 show a second embodiment of the electromagnetic short side weir 11. The same members as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. The electromagnetic short side weir 11 is located above the kiss point 9 in a predetermined gap formed between the magnetic pole 15 having a flat opposing surface and the end face 1a of the mold roll 1 in order to prevent the passage of excess alternating magnetic flux. And a pair of left and right magnetic adjustment plates 12, 12 for shielding a predetermined range. When the distance between the mold roll 1 and the magnetic pole 5 is sufficiently large, the magnetic adjusting plate 12 may be a paramagnetic material such as austenitic stainless steel. A copper plate, which is a magnetic material, is suitable. Although the magnetic flux density can be adjusted by using a ferromagnetic metal plate, an alternating magnetic field is not suitable because heat is generated and loss is large. The magnetic adjustment plate 12 made of a paramagnetic material collects the alternating magnetic flux passing therethrough and allows the magnetic flux to pass therethrough, thereby reducing the alternating magnetic flux passing through the mold roll 1 side. Further, the diamagnetic material works to weaken the alternating magnetic flux passing therethrough, so that the alternating magnetic flux penetrating to the mold roll 1 side can be reduced. Therefore, the magnetic flux density acting on the molten metal S can be adjusted by setting the material, the size, the plate thickness, the disposition position, and the like of the magnetic adjustment plate 12. It is possible to form an appropriate magnetic flux density at which an electromagnetic pressure Pm close to the pressure P required for holding can be obtained. Although not shown, a cooling passage is formed in each of the magnetic adjusting plates 12 and 12 to supply a cooling medium, for example, cooling water, to protect the molten metal S from heat.

The left and right magnetic adjustment plate units 12 are
As the arranged gap G is smaller, the alternating magnetic flux m is more likely to pass through the inside of the paramagnetic material, and the alternating magnetic flux m is less likely to enter the mold roll 1 side. Therefore, both magnetic adjustment plates 1
The magnets 2, 12 are arranged so as to be movable in the approaching / separating direction, and the magnetism adjusting devices 13, 13 having a well-known position adjusting mechanism such as a screw shaft are moved toward and away from the magnetism adjusting plate 12, thereby acting on the molten metal S. Magnetic flux density can be adjusted. Therefore, when the casting state such as the slab thickness, casting speed, and level of the molten metal is changed, the magnetic adjustment device 13
Is driven to move the magnetic adjustment plates 12 toward and away from each other, and by adjusting the gap G, the magnetic flux density can be easily adjusted. It is possible to form a magnetic field having an appropriate magnetic flux density at which an approximate electromagnetic pressure Pm can be obtained. Therefore, the generation of excess alternating magnetic flux at the end of the mold roll 1 can be prevented, and overheating can be prevented.

FIG. 8 shows a third embodiment provided with an electromagnetic short side dam 21 in which the magnetic pole 5 of the first embodiment and the magnetic adjustment plate 12 and the magnetic adjustment device 13 of the second embodiment are combined. The same members as those in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

According to the electromagnetic short side weir 21 of the third embodiment, the alternating magnetic flux reaching the end of the mold roll 1 is adjusted by the distance L between the magnetic pole 5 and the end face of the mold roll 1 and the magnetic flux is adjusted. By adjusting the alternating magnetic flux reaching the end of the mold roll 1 with the adjusting plate 12, the magnetic flux density acting on the molten metal S can be adjusted over a wide range, and the magnetic field having an appropriate magnetic flux density is applied to the end of the mold roll 1. Can be formed. Therefore, the generation of excess alternating magnetic flux at the end of the mold roll 1 can be prevented beforehand, and overheating can be prevented.

[0028]

As described above, according to the first configuration of the present invention, by disposing a shielding material between magnetic poles,
By diverting all the alternating magnetic flux to the mold roll side and passing the mold roll and the molten metal, the rib provided at the edge of the mold roll becomes unnecessary, and furthermore, by adjusting the distance between the magnetic pole and the mold roll ,
By controlling the magnetic flux density, the electromagnetic pressure generated by the alternating magnetic flux can be brought close to the pressure required for holding the molten metal,
With an extremely simple configuration, it is possible to prevent the end of the ferromagnetic mold roll from being overheated. In addition, in the closest part of the mold roll having a large amount of excess alternating magnetic flux, the mold roll and the magnetic pole are separated from each other, so that the magnetic pole can be easily cooled and damage at the time of breakout can be reduced.

According to the second configuration, the magnetic adjusting plate is disposed in the gap between the magnetic pole and the end face of the mold roll, and the alternating magnetic flux is passed through the magnetic adjusting plate to shield the magnetic field to reduce or reduce it by half. By reducing the excess alternating magnetic flux in the kiss portion, the electromagnetic pressure generated by the alternating magnetic flux can be made closer to the pressure required for holding the molten metal, and the ferromagnetic mold roll can be prevented from overheating.

Further, by combining the first and second configurations, the control of the alternating magnetic flux can be further facilitated. Furthermore, in response to changes in casting conditions such as slab thickness, casting speed, and level of the molten metal, the magnetic adjusting device moves the magnetic adjusting plate closer and further away to adjust the alternating magnetic flux passing therethrough. Generation can be prevented beforehand, and overheating of the end portion of the mold roll made of a ferromagnetic material can be prevented beforehand.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of an electromagnetic short side weir in a twin-roll type thin plate continuous casting facility according to the present invention.

FIG. 2 is a front view of the electromagnetic short side weir.

FIG. 3 is a perspective view of the electromagnetic short side weir.

FIG. 4 is a sectional view taken along a line II shown in FIG. 1;

FIG. 5 is a sectional view taken along the line II-II shown in FIG.

FIG. 6 is a front view showing a second embodiment of the electromagnetic short side weir according to the present invention.

FIG. 7 is a sectional view taken along the line III-III shown in FIG.

FIG. 8 is a side view showing a third embodiment of the electromagnetic short side weir according to the present invention.

FIG. 9 is a front view showing a conventional electromagnetic short side weir.

FIG. 10 is a sectional view taken along the line IV-IV shown in FIG. 9;

FIG. 11 is a sectional view taken along line VV shown in FIG. 9;

FIG. 12 is a graph showing a holding pressure and an electromagnetic pressure of a molten metal in a conventional electromagnetic short side weir.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold roll 1a End surface 2 Electromagnetic short side weir 3 Melt receiver 4 Magnet core 5 Magnetic pole 6 Magnet coil 7 Electromagnetic shield cover 8 Shielding material 9 Kiss point (closest part) 11 Electromagnetic short side weir 12 Magnetic adjustment plate 13 Magnetic adjustment device 21 Electromagnetic short side weir S Molten m Alternating magnetic flux L Distance G Gap

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B22D 11/06 330 B22D 11/01

Claims (4)

(57) [Claims] A molten metal is supplied between a pair of ferromagnetic mold rolls arranged in parallel with each other and rotated on the surface of the mold roll by rotating the mold rolls in a relative direction to sandwich the molten metal. Electromagnetic short side weir of twin roll type continuous sheet casting equipment for producing thin sheets by continuously pressing the cast slab shell from the closest part of the mold roll by pressing the cast slab, and provided at the end of the magnet core The paired magnetic poles are arranged along the outer periphery of the mold roll at locations where the molten metal is held, and a shielding material made of a diamagnetic and paramagnetic metal material is interposed between these magnetic poles. It is arranged so that the alternating magnetic flux passes through the melt from the end of the mold roll, and the distance from the magnetic poles to the end face of the mold roll is adjusted according to the level of the melt in the melt. An electromagnetic short side of a twin-roll thin-sheet continuous casting facility, characterized in that the closest side of the mold roll is set to be long so as to form a magnetic field that generates an electromagnetic pressure corresponding to a pressure capable of holding hot water. Weir. The molten metal is supplied between a pair of ferromagnetic mold rolls arranged in parallel with each other, and the mold rolls are rotated in a relative direction to sandwich the molten metal, thereby forming the surface of the mold rolls. Electromagnetic short side weir of twin roll type continuous sheet casting equipment for producing thin sheets by continuously pressing the cast slab shell from the closest part of the mold roll by pressing the cast slab, and provided at the end of the magnet core The paired magnetic poles are arranged along the outer periphery of the mold roll at a location for holding the molten metal and with a fixed gap at the end face of the mold roll, and a shield material made of a diamagnetic material is arranged between these magnetic poles. And the alternating magnetic flux passes through the melt from the end of the mold roll, and the magnetic flux density formed in the melt can be adjusted in the gap between each magnetic pole and the end face of the mold roll. An electromagnetic short side weir of a twin-roll type thin plate continuous casting facility, wherein a pair of magnetic adjustment plates are disposed. 3. A gap between each magnetic pole and an end face of a mold roll,
2. The electromagnetic short side weir of the twin-roll type continuous sheet casting apparatus according to claim 1, wherein a pair of magnetic adjusting plates capable of adjusting the magnetic flux density of the molten metal at the end are disposed. 4. The electromagnetic short side weir of a twin-roll type thin plate continuous casting facility according to claim 2, further comprising a magnetic adjusting device for moving the pair of magnetic adjusting plates toward and away from each other.