Note: Descriptions are shown in the official language in which they were submitted.
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MOLDING DEVICE FOR CONTINUOUS CASTING EQUIPPED WITH
AGITATOR
Technical Field
[0001]
The present invention relates to a molding device for
continuous casting, which is equipped with an agitator, of
continuous casting equipment that produces a billet, a slab or the
like made of non-ferrous metal of a conductor (conductive body),
such as Al, Cu, Zn, or an alloy of at least two of them, or an Mg
alloy, or other metal.
Background Art
[0002]
In the past, a melt agitating method to be described below
has been employed in a casting mold for continuous casting. That
is, for the improvement of the quality of a slab, a billet, or the like,
in a process for solidifying the melt, that is, when the melt passes
through the casting mold, a moving magnetic field, which is
generated from the outside of the casting mold by an
electromagnetic coil, is applied to the melt present in the casting
mold so that agitation occurs in the melt not yet solidified. A main
object of this agitation is to degas the melt and to uniformize the
structure. However, since the electromagnetic coil is disposed at
the position close to high-temperature melt, the cooling of the
electromagnetic coil and troublesome maintenance are needed and
large power consumption is obviously needed. In addition, the
generation of heat from the electromagnetic coil itself caused by
the power consumption cannot be avoided, and this heat should be
removed. For this reason, there are various problems in that the
device itself cannot but become expensive, and the like.
Citation List
Patent Literature
[0003]
Patent Literature 1: JP 9-99344 A
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Summary of Invention
Technical Problem
[0004]
The invention has been made to solve the above-mentioned problems,
and an object of the invention is to provide a molding device for continuous
casting
equipped with an agitator that reduces the amount of generated heat, is easy
to carry
out maintenance, is inexpensive, and is easy to use in practice.
[0005]
A molding device for continuous casting equipped with an agitator
according to an embodiment of the present invention is a device which receives
liquid-phase melt of a conductive material and from which a solid-phase cast
product
is taken out through the cooling of the melt. The molding device includes a
casting
mold including a casting space that includes an inlet and an outlet at a
central portion
of a substantially cylindrical side wall and a magnetic field generation
device
receiving chamber that is formed in the side wall and is positioned outside
the casting
space, the casting mold receiving the liquid-phase melt from the inlet into
the casting
space and discharging the solid-phase cast product from the outlet through the
cooling in the casting space, and an agitator provided so as to correspond to
the
casting mold, the agitator including a magnetic field generation device having
an
electrode unit that includes first and second electrodes supplying current to
at least
the liquid-phase melt present in the casting space, and a permanent magnet
that
applies a magnetic field to the liquid-phase melt. The magnetic field
generation
device is received in the magnetic field generation device receiving chamber
of the
casting mold, generates magnetic lines of force toward a center in a lateral
direction,
makes the magnetic lines of force pass through a part of the side wall of the
casting
mold and reach the casting space, and applies lateral magnetic lines of force,
which
cross the current, to the melt.
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2a
[0005a]
An aspect of the invention relates to a molding device for continuous
casting equipped with an agitator which receives liquid-phase melt of a
conductive
material and from which a solid-phase cast product is taken out through the
cooling of
the melt, the molding device comprising: a casting mold including a casting
space
that includes an inlet and an outlet at a central portion of a cylindrical
side wall and a
magnetic field generation device receiving chamber that is formed in the side
wall
and is positioned outside the casting space, the casting mold receiving the
liquid-
phase melt from the inlet into the casting space and discharging the solid-
phase cast
product from the outlet through the cooling in the casting space; and an
agitator
provided so as to correspond to the casting mold, the agitator including a
magnetic
field generation device having an electrode unit that includes first and
second
electrodes supplying current having a frequency of 1 to 5 Hz to at least the
liquid-
phase melt present in the casting space, and a permanent magnet that applies a
magnetic field to the liquid-phase melt, wherein the magnetic field generation
device
is received in the magnetic field generation device receiving chamber of the
casting
mold, generates magnetic lines of force toward a center in a lateral
direction, makes
the magnetic lines of force pass through a part of the side wall of the
casting mold
and reach the casting space, and applies lateral magnetic lines of force,
which cross
the current, to the melt, wherein the magnetic field generation device
receiving
chamber includes an opening that is formed in the side wall of the casting
mold so as
to be opened downward, wherein the opening of the magnetic field generation
device
receiving chamber is closed by a lid, and the magnetic field generation device
receiving chamber functions as a cooling chamber that allows the flow of
cooling
water.
[0005b]
Another aspect of the invention relates to a molding device for
continuous casting equipped with an agitator which receives liquid-phase melt
of a
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2b
conductive material and from which a solid-phase cast product is taken out
through
the cooling of the melt, the molding device comprising: a casting mold
including a
casting space that includes an inlet and an outlet at a central portion of a
cylindrical
side wall and a magnetic field generation device receiving chamber that is
formed in
the side wall and is positioned outside the casting space, the casting mold
receiving
the liquid-phase melt from the inlet into the casting space and discharging
the solid-
phase cast product from the outlet through the cooling in the casting space;
and an
agitator provided so as to correspond to the casting mold, the agitator
including a
magnetic field generation device having an electrode unit that includes first
and
second electrodes supplying current having a frequency of 1 to 5 Hz to at
least the
liquid-phase melt present in the casting space, and a permanent magnet that
applies
a magnetic field to the liquid-phase melt, wherein the magnetic field
generation
device is received in the magnetic field generation device receiving chamber
of the
casting mold, generates magnetic lines of force toward a center in a lateral
direction,
makes the magnetic lines of force pass through a part of the side wall of the
casting
mold and reach the casting space, and applies lateral magnetic lines of force,
which
cross the current, to the melt, wherein the magnetic field generation device
is
provided in the magnetic field generation device receiving chamber so that the
position of the magnetic field generation device is adjustable in a vertical
direction
according to the position of an interface between liquid-phase melt and a
solid-phase
product present in the casting space.
[0005c]
Another aspect of the invention relates to a molding device for
continuous casting equipped with an agitator which receives liquid-phase melt
of a
conductive material and from which a solid-phase cast product is taken out
through
the cooling of the melt, the molding device comprising: a casting mold
including a
casting space that includes an inlet and an outlet at a central portion of a
cylindrical
side wall and a magnetic field generation device receiving chamber that is
formed in
the side wall and is positioned outside the casting space, the casting mold
receiving
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2c
the liquid-phase melt from the inlet into the casting space and discharging
the solid-
phase cast product from the outlet through the cooling in the casting space;
and an
agitator provided so as to correspond to the casting mold, the agitator
including a
magnetic field generation device having an electrode unit that includes first
and
second electrodes supplying current having a frequency of 1 to 5 Hz to at
least the
liquid-phase melt present in the casting space, and a permanent magnet that
applies
a magnetic field to the liquid-phase melt wherein the magnetic field
generation device
is received in the magnetic field generation device receiving chamber of the
casting
mold, generates magnetic lines of force toward a center in a lateral
direction, makes
the magnetic lines of force pass through a part of the side wall of the
casting mold
and reach the casting space, and applies lateral magnetic lines of force,
which cross
the current, to the melt, wherein a power supply, which supplies alternating
current
between the first and second electrodes, is connected to the first and second
electrodes.
[0005d]
Another aspect of the invention relates to a molding device for
continuous casting equipped with an agitator which receives liquid-phase melt
of a
conductive material and from which a solid-phase cast product is taken out
through
the cooling of the melt, the molding device comprising: a casting mold
including a
casting space that includes an inlet and an outlet at a central portion of a
cylindrical
side wall and a magnetic field generation device receiving chamber that is
formed in
the side wall and is positioned outside the casting space, the casting mold
receiving
the liquid-phase melt from the inlet into the casting space and discharging
the solid-
phase cast product from the outlet through the cooling in the casting space;
and an
agitator provided so as to correspond to the casting mold, the agitator
including a
magnetic field generation device having an electrode unit that includes first
and
second electrodes supplying current to at least the liquid-phase melt present
in the
casting space, and a permanent magnet that applies a magnetic field to the
liquid-
phase melt, wherein the magnetic field generation device is received in the
magnetic
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2d
field generation device receiving chamber of the casting mold, generates
magnetic
lines of force toward a center in a lateral direction, makes the magnetic
lines of force
pass through a part of the side wall of the casting mold and reach the casting
space,
and applies lateral magnetic lines of force, which cross the current, to the
melt,
wherein the magnetic field generation device receiving chamber functions as a
cooling chamber that allows the flow of cooling water.
Brief Description of Drawings
=
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[0006]
Fig. 1(a) is a view' illustrating the entire structure of an
embodiment of the invention, and Figs. 1(b) and 1(c) are
explanatory views illustrating the operation thereof.
Fig. 2(a) is an explanatory plan view taken along line II(a) -
II(a) of Fig. 1 and Fig. 2(b) is an explanatory view illustrating the
bottom of an outer casting mold.
Fig. 3(a) is an explanatory plan view of a magnetic field
generation device 31 of an agitator 3, and Fig. 3(b) is an
explanatory plan view of a modified example thereof.
Fig. 4(a) is a plan view of another modified example of the
magnetic field generation device 31 of the agitator 3, and Fig. 4(b)
is an explanatory plan view of a modified example thereof.
Fig. 5 is a view illustrating the entire structure of another
embodiment of the invention.
Fig. 6 is a view illustrating the entire structure of another
embodiment of the invention.
Fig. 7 is a view illustrating the entire structure of still
another embodiment of the invention.
Fig. 8(a) is a view illustrating the entire structure of yet
another embodiment of the invention, Fig. 8(b) is a cross-sectional
view taken along line VIII(b) - VIII(b) of Fig. 8(a), Fig. 8(c) is a
cross-sectional view taken along line VIII(c) - VIII(c) of Fig. 8(a),
Fig. 8(d) is an explanatory plan view of a magnetic field generation
device, and Fig. 8Ã is an explanatory plan view of a lid.
Fig. 9(a) is a view illustrating the entire structure of still
another embodiment of the invention, Fig. 9(b) is a cross-sectional
view taken along line IX(b) - IX(b) of Fig. 9(a), and Fig. 9(c) is an
explanatory plan view of a magnetic field generation device.
Fig. 10 is a view illustrating the entire structure of yet
another embodiment of the invention.
Description of Embodiments
[0007]
For deeper understanding of an embodiment of the
invention, an electromagnetic agitator, which uses electricity as
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power, of continuous casting equipment in the related art will be
described briefly. '
[0008]
In the related art, a fixed amount of melt M of non-ferrous
metal is discharged from a melt receiving box that is called a
tundish and is poured into a casting mold that is provided on the
lower side. Cooling water for cooling the casting mold is circulated
in the casting mold. Accordingly, high-temperature melt starts to
solidify from the outer periphery thereof (a portion thereof close to
the casting mold) from the moment that the high-temperature melt
comes into contact with the casting mold.
Since the melt, which is positioned at the central portion of
the casting mold, is distant from the wall of the casting mold that is
being cooled, the solidification of the melt positioned at the central
portion of the casting mold is obviously later than that of the melt
positioned at the peripheral portion of the casting mold. For this
reason, two kinds of melt, that is, liquid (liquid-phase) melt and a
solid (solid-phase) cast product are simultaneously present in the
casting mold while being adjacent to each other with an interface
interposed therebetween. Further, generally, if melt is solidified
too rapidly, gas remains in the cast product (product) having been
changed into a solid and causes the quality of the product to
deteriorate. For this reason, degassing is facilitated by the
agitating of the melt that is not yet solidified. The electromagnetic
agitator, which uses electricity as power, has been used for the
agitating in the related art.
[0009]
However, when such an electromagnetic agitator is used,
there are various difficulties as described above.
[0010]
Accordingly, the invention is to provide a molding device for
continuous casting equipped with an agitator that does not use the
electromagnetic agitator using electricity as power and uses
permanent magnets.
[0011]
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An embodiment of the invention will be described in more
detail below.
[0012]
The entire structure of an embodiment of the invention is
5 illustrated in Fig. 1(a). Fig. 2(a) is an explanatory plan view taken
along line 11(a) - 11(a) of Fig. 1(a), and mainly illustrates a part of
an agitator 3 and a casting mold 2, and Fig. 3(a) is an explanatory
plan view of the magnetic field generation device 31 of the agitator
3.
[0013]
As understood from Fig. 1(a), a device according to an
embodiment of the invention broadly includes a melt supply unit 1
that supplies melt M of non-ferrous metal of a conductor
(conductive body), such as Al, Cu, Zn, or an alloy of at least two of
them, or an Mg alloy, or other metal; a casting mold 2 that
receives the melt from the melt supply unit 1; and an agitator 3
that agitates the melt M present in the casting mold 2. A central
portion of the casting mold 2 forms a so-called casting space 2A(1)
that includes an inlet 2A(1)1 and an outlet 2A(1)2.
[0014]
The melt supply unit 1 includes a tundish (melt receiving
box) 1A that receives melt M from a ladle (not illustrated) or the
like. The melt M is stored in the tundish (melt receiving box) 1A,
inclusion is removed from the melt, and the melt M is supplied to
the casting mold 2 from a lower opening 1B of the tundish at a
constant supply rate. Only the tundish (melt receiving box) 1A is
illustrated in Fig. 1.
[0015]
The casting mold 2 is adapted in this embodiment so that a
columnar product P (billet) is taken out from the casting mold. For
this purpose, the casting mold 2 is formed so as to have a
substantially cylindrical double structure (of which the cross-section
has a ring shape). That is, the casting mold 2 includes an inner
casting mold 21 and an outer casting mold 22 that are fitted to
each other. The inner casting mold 21 is provided on the inside
and made of a non-conductive material (non-conductive refractory
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material) such as graphite (carbon). The outer casting mold 22 is
provided on the outside and made of a conductive material
(conductive refractory material), such as aluminum or copper.
As described in detail below, the magnetic field generation
device 31 is assembled so as to be received within the side wall of
the outer casting mold 22. Meanwhile, since the technical idea is
the same as described above even when a prismatic product (slab)
is taken out, the technical idea of an embodiment to be described
below can be applied as it is. Briefly, the shapes of components
corresponding to a rectangular slab, which is a product, are merely
changed.
[0016]
The casting mold 2 further includes a water jacket 23
outside the outer casting mold 22.
The water jacket 23 is to cool the melt M that flows into the
inner casting mold 21. That is, cooling water flows into the water
jacket 23 from an inlet (not illustrated) and is circulated in the
water jacket 23, the outer portion of the outer casting mold 22 is
cooled by the cooling water, and the cooling water is discharged
from an outlet (not illustrated). The melt M is rapidly cooled by
the water jacket 23. Since water jackets having various known
structures may be employed as the water jacket 23, the detailed
description thereof will not be provided here.
[0017]
In addition, a plurality of electrode insertion holes 2a, 2a,
into which electrodes 32A to be described below are inserted are
formed at a predetermined interval on the circumference of the
casting mold 2 having the above-mentioned structure. The
electrode insertion holes 2a are formed so as to be inclined
downward toward the center of the casting mold 2. For this
reason, if the surface of the melt M is lower than the upper
openings of the electrode insertion holes 2a even though the melt
M is contained in the casting mold 2, there is no concern that the
melt M will leak to the outside.
[0018]
As described above, briefly, the agitator 3 is provided so as
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to be built in the side wall .of the casting mold 2. The agitator 3
includes a permanent magnet type magnetic field generation
device 31, and a pair of upper and lower electrodes (positive and
negative electrodes) 32A and 32B.
[0019]
In particular, as understood from Fig. 3(a), the magnetic
field generation device 31 is formed in the shape of a ring (in a
frame shape). The entire inner peripheral portion of the magnetic
field generation device may be magnetized to an N pole, and the
entire outer peripheral portion of the magnetic field generation
device may be magnetized to an S pole. Further, four portions of
the inner and outer peripheral portions may be partially
magnetized to an N pole and an S pole as illustrated in, for
example, Fig. 3(a), respectively.
[0020]
As understood from the following description, the magnetic
field generation device 31 does not necessarily need to be formed
in the shape of a ring, and may be divided. That is, for example,
as illustrated in Fig. 8(d), the cross-section of the magnetic field
generation device may be formed of a plurality of arc-shaped
permanent magnet pieces (Fig. 4). As briefly described above,
particularly, as understood from Fig. 1(a), the magnetic field
generation device 31 is assembled in the outer casting mold 22.
[0021]
In more detail, as understood from Fig. 1(a), the outer
casting mold 22 includes a magnetic field generation device
receiving chamber 22a which is formed in the side wall thereof and
has a ring-shaped cross-section and of which a lower portion forms
a release port. The magnetic field generation device receiving
chamber 22a is also understood from Fig. 2(b). Fig. 2(b) is a view
of the outer casting mold 22 when the outer casting mold 22 is
seen from below. In particular, as understood from Fig. 1(a), the
magnetic field generation device 31 also having a ring-shaped
cross-section is received in the magnetic field generation device
receiving chamber 22a, which has a ring-shaped cross-section and
of which the lower portion is opened, from below so that the
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position of the magnetic field generation device in the vertical
direction can be adjusted by movement. That is, the magnetic
field generation device 31 is provided so that the height of the
magnetic field generation device can be adjusted in the magnetic
field generation device receiving chamber 22a by desired units (not
illustrated). Accordingly, it is possible to more efficiently agitate
the melt M as described below by adjusting the height of the
magnetic field generation device so as to correspond to
liquid-phase melt M as understood from Fig. 1(a). The lower
opening of the magnetic field generation device receiving chamber
22a is closed by a ring-shaped lid 22B. The lid 22B may be
formed so as to include discharge channels 226 (1) for discharging
cooling water to the outside such as a lid 22B of Fig. 8(a) to be
described below.
[0022]
As described above, the four portions of the magnetic field
generation device 31 are magnetized and form pairs of magnetic
poles 31a, 31a, as illustrated in Fig. 3(a). That is, a portion of
each of the magnetic poles 31a, 31a facing the inside of the
ring-shaped magnetic field generation device is magnetized to an N
pole, and a portion thereof facing the outside of the ring-shaped
magnetic field generation device is magnetized to an S pole.
Accordingly, magnetic lines of force ML generated from the N pole
horizontally pass through the melt M that is present in the casting
mold 2.
The magnetization may be contrary to this. That is, the
inner portions of all magnetic poles may be magnetized to a certain
pole and the outer portions thereof may be magnetized to an
opposite pole. One of additional characteristics of the invention is
that a plurality of magnetic poles are disposed at a plurality of
positions surrounding the melt M, which is not yet solidified, as
understood from Fig. 3(a). Accordingly, it is possible to improve
the quality of the product P by agitating all the melt M with an
electromagnetic force that is generated according to Fleming's rule
by magnetic lines of force and current as described below.
Therefore, the number of the magnetic poles is four in Fig. 3(a),
,
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but is not limited to four and, may be arbitrary.
Further, as
described above, the magnetic field generation device 31 does not
need to be formed of a ring-shaped single body, and may be
divided into a plurality of magnet bodies (magnet pieces), of which
the number is arbitrary, as illustrated in Fig. 8(d).
[0023]
In Fig. 1(a), current flows between the pair of electrodes
32A and 32B through the melt M and a cast product (product) P.
One electrode 32A may be used, but a plurality of electrodes 32A
may be used. In this embodiment, two electrodes 32A are used.
The electrodes 32A are formed in the shape of a probe.
The respective electrodes 32A are inserted into the
above-mentioned electrode insertion holes 2a. That is, the
electrodes 32A penetrate into the casting mold 2 (the inner casting
mold 21 and the outer casting mold 22) from the water jacket 23.
Inner ends of the electrodes 32A are exposed to the inside of the
inner casting mold 21, come into contact with the melt M, and
conduct electricity to the melt M. Outer ends of the electrodes
32A are exposed to the outside of the water jacket 23. The outer
ends are connected to a power supply 34 that can supply variable
direct current. The power supply 34 may have the function of an
AC power supply as described below, and may have a function of
changing frequency. The electrodes 32A may be supported above
the upper opening of the casting mold 2 without penetrating the
side wall of the casting mold 2 so that the inner ends of the
electrodes 32A are inserted into the melt M from the surface of the
melt M flowing into the casting mold 2. The electrodes 32A may
be electrically connected to the inner casting mold 21 made of
graphite or the like.
[0024]
The number of electrodes used as the electrodes 32A may
be arbitrary, and an arbitrary number of the electrodes 32A may be
inserted into arbitrary electrode insertion holes of the electrode
insertion holes 2a, 2a, ¨.
[0025]
In Fig. 1(a), the lower electrode 32B is provided so that the
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position of the lower electrode 32B is fixed. The electrode 32B is
formed of a roller type electrode. That is, the lower electrode 32B
includes a rotatable roller 32Ba at the end thereof. The roller
32Ba comes into press contact with the outer surface of a columnar
5 product P as a cast product (a billet or a slab) that is extruded in a
solid phase state. Accordingly, as the product P extends
downward, the roller 32Ba is rotated. That is, when the product P
is extruded downward, the product P extends downward in Fig. 1
while coming into contact with the roller 32Ba and rotating the
10 roller 32Ba.
[0026]
Accordingly, when a voltage is applied between the pair of
electrodes 32A and 32B from the power supply 34, current flows
between the pair of electrodes 32A and 32B through the melt M
and the product P. As described above, the power supply 34 is
adapted so as to be capable of controlling the amount of current
flowing between the pair of electrodes 32A and 32B. Therefore, it
is possible to select current where the liquid-phase melt M can be
agitated most efficiently in a relationship with the magnetic lines
of force ML.
[0027]
Next, the operation of the device having the
above-mentioned structure will be described.
[0028]
In Fig. 1(a), a fixed amount of the melt M, which is
discharged from the tundish (melt receiving box) 1A, is input to the
upper portion of the casting mold 2. The casting mold 2 is cooled
through the circulation of water in the water jacket 23, so that the
melt M present in the casting mold 2 is rapidly cooled and solidified.
However, the melt M present in the casting mold 2 has a two-phase
structure where the upper portion of the melt is liquid (liquid
phase), the lower portion thereof is solid (solid phase), and the
upper and lower portions of the melt are adjacent to each other at
an interface ITO. When passing through the casting mold 2, the
melt M is formed in the shape (a columnar shape in this
embodiment) corresponding to the shape of the casting mold.
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Accordingly, a product P as a slab or billet is continuously formed.
[0029]
Further, since the permanent magnet type magnetic field
generation device 31 is received in the side wall of the casting mold
2 as understood from Fig. 1(a) and the like, the magnetic field
(magnetic lines of force ML) of the magnetic field generation device
reaches the melt M, which is present in the casting mold 2, in the
lateral direction. In this state, when direct current is supplied to
the lower electrode 32B from the upper electrodes 32A by the
power supply 34, the current flows to the lower electrode 32B from
the upper electrodes 32A through the melt (liquid phase) M of
aluminum or the like and the product (solid phase) P. At this time,
the current crosses the magnetic lines of force ML, which are
generated from the permanent magnet type magnetic field
generation device 31, substantially at right angles to the magnetic
lines of force. Accordingly, rotation occurs in the liquid-phase melt
M in accordance with Fleming's left-hand rule. The melt M is
agitated in this way, so that impurities, gas, and the like contained
in the melt M float and so-called degassing is actively performed.
Accordingly, the quality of the product (a slab or a billet) P is
improved.
[0030]
Now, cooling capacity is increased or reduced by the water
jacket 23 or the like, the solidification rate of the melt M is changed
and the interface ITO between the melt (liquid-phase) M and a
product (solid-phase) P moves up and down according to this.
That is, when cooling capacity is increased, the interface ITO moves
up like an interface IT1 as illustrated in Fig. 1(b). When cooling
capacity is reduced, the interface ITO moves down like an interface
IT2 as illustrated in Fig. 1(c). Further, it is preferable that the
magnetic field generation device 31 be moved up and down
according to the positions of the interfaces ITO, IT1, and IT2 in
order to efficiently agitate the melt M. Accordingly, it is possible to
obtain a product P as a high-quality product by reliably and
efficiently agitating the melt M. For this purpose, the magnetic
field generation device is adapted so that the height of the
,
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magnetic field generation device 31 can be adjusted in the vertical
direction according to the heights of these interfaces IT1 and IT2
as illustrated in Figs. 1(b) and 1(c) and the position of the
magnetic field generation device 31 can be kept. Accordingly, it is
possible to efficiently agitate the melt M as described above.
[0031]
On the contrary, the double structure of the casting mold 2
may be formed so that the inner portion of the casting mold is
made of a conductive material and the outer portion thereof is
made of a non-conductive material. In this case, at least the
electrodes 32A may come into electronically contact with the
conductive material that forms the inner portion of the casting
mold. Even in this case, a magnetic field generation device
receiving chamber 22a may be formed in an outer member.
[0032]
Further, the casting mold 2 may have not a double structure
but a single structure. In this case, the casting mold 2 may be
made of only a conductive material, and the electrodes 32A may
conduct electricity to the casting mold 2. The structure of the
other electrode 32B may be the same as described above.
[0033]
On the contrary, the casting mold 2 may be made of only a
non-conductive material. In this case, it is necessary to make the
electrodes 32A conduct electricity to the melt M present in the
casting mold 2 by making the electrodes 32A penetrate into the
casting mold 2 as illustrated in Fig. 1(a).
[0034]
In these cases, obviously, a magnetic field generation device
receiving chamber 22a may be formed in a member having a single
structure.
[0035]
A magnetic field generation device 31A of Fig. 3(b) may be
used instead of magnetic field generation device 31 of Fig. 3(a).
The magnetization direction of the magnetic field generation device
31A of Fig. 3(a) is opposite to that of the magnetic field generation
device 31 of Fig. 3(b). Both the magnetic field generation devices
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13
have the same function.
[0036]
Further, magnetic field generation devices 31-2 and 31A-2
of Figs. 4(a) and 4(b) may be used instead of the magnetic field
generation devices 31 and 31A of Figs. 3(a) and 3(b). The
magnetic field generation devices 31-2 and 31A-2 of Figs. 4(a) and
4(b) are adapted so that a plurality of rod-like permanent magnets
PM are fixed to the inside of a ring-shaped support (yoke) SP.
These have the same function.
[0037]
Furthermore, an electrode, which includes the roller 32Ba at
the end thereof, has been described as the lower electrode 32B in
the above-mentioned embodiment. However, the lower electrode
does not need to necessarily include the roller 32Ba. Even though
a product P is continuously extruded, the electrode 32B only has to
conduct electricity to the product P and may employ various
structures. For example, an elastic member having a
predetermined length is used as the electrode 32B and is bent, for
example, so as to be convex upward or downward in Fig. 1, and
the end of the elastic member comes into press contact with the
cast product P by the force of restitution. In this state, the cast
product P may be allowed to extend downward.
[0038]
According to the above-mentioned embodiment of the
invention, it is possible to obtain the following effects.
[0039]
In the embodiment of the invention, melt M that is not yet
solidified is agitated to give movement, vibration, and the like to
the melt M, so that a degassing effect and the uniformization and
refinement of the structure are achieved.
[0040]
In more detail, since the magnetic field generation device 31
is adapted so as to be capable of being adjusted in the vertical
direction in the embodiment of the invention, it is possible to obtain
a high-quality product P by reliably agitating the melt M. This is
one of the characteristics of the invention as described above, and
= CA 02829183 2013-09-05
14
an idea, in which a magnetic field generation device 31 provided
outside the casting mold is moved up and down in a device that is
apt to be high temperature and large in size and hardly has an
empty space as in the embodiment of the invention, itself is an
idea that is not accustomed to those skilled in the art. Accordingly,
a technique of the invention, in which a magnetic field generation
device is received in a casting mold and can be adjusted in the
vertical direction, is a technical idea that is peculiar to the inventor.
[0041]
Further, since the magnetic field generation device 31 is
formed in the embodiment of the invention so that a plurality of
magnetic poles are disposed at the positions surrounding the melt
M or a ring-shaped magnet surrounding the melt M is disposed, it
is possible to efficiently agitate all the melt M with an
electromagnetic force that is generated according to Fleming's rule
by magnetic lines of force and current. Accordingly, it is possible
to obtain a product P as a high-quality product. That is, in the
embodiment of the invention, it is possible to efficiently agitate the
melt M by making the best use of an electromagnetic force that is
generated according to Fleming's rule. In addition, the axis of the
rotation of the melt M, which is caused by this agitating of the melt,
is an axis parallel to the center axis of the product P in Fig. 1(a).
Accordingly, it is possible to obtain a high-quality product as a
product P by making the rotational drive of the melt M reliable.
[0042]
Moreover, in the embodiment of the invention, melt M is
agitated with an electromagnetic force that is generated according
to Fleming's rule and is agitated by the cooperation between small
current flowing in the melt M and a magnetic field generated from
the magnetic field generation device 31. Accordingly, it is possible
to obtain a device that stably and continuously expects reliable
agitation unlike melting and agitation performed using the
intermittent flow of large current according to the principle of arc
welding or the like and has low noise and high durability.
[0043]
It is obvious that the above-mentioned effects are obtained
CA 02829183 2013-09-05
from all embodiments to be described below.
[0044]
Meanwhile, direct current has been supplied between the
electrodes 32A and 32B in the above description, but alternate
5 current having a low frequency of about 1 to 5 Hz may be supplied
from the power supply 34. In this case, the melt M does not
rotate but repeatedly vibrates according to the cycle thereof in the
relationship with a magnetic field that is generated from the
magnetic field generation device 31. Impurities are removed from
10 the melt M even by the vibration. This modified example may be
applied to all embodiments to be described below. In this case, it
is obvious that a power supply having a function of changing
frequency is employed as the power supply 34.
[0045]
15
Further, the realization of mass production facilities is
currently required in the industry. It is
essential to realize a
casting mold that is as small as possible when mass production is
considered.
[0046]
Here, the electromagnetic agitating device in the related art
can cope with a case where several slabs or billets are produced at
one time. However, at present, there is a demand for the
production of billets of which the number exceeds 100. The
electromagnetic agitator in the related art cannot cope with this
demand.
[0047]
However, permanent magnets are used as the magnetic
field generation device in the device of the invention. For this
reason, it is possible to make the device very compact in
comparison with the electromagnetic agitator that is supplied with
large current. Accordingly, it is possible to sufficiently realize a
molding device for a mass production facility. Further, since the
magnetic field generation device is permanent magnet type, it is
possible to obtain a device having effects, such as no heat
generation, power saving, energy saving, and less maintenance, as
a magnetic field generation device.
CA 02829183 2013-09-05
16
[0048]
Fig. 5 illustrates another embodiment of the invention.
[0049]
More current is supplied to this liquid-phase melt M to
generate a larger electromagnetic force so that the melt M is
rotationally driven.
[0050]
This embodiment is different from the embodiment of Fig.
1(a) in the structure of a casting mold 2A. Other structures are
substantially the same as Fig. 1(a). Accordingly, the detailed
description thereof will not be repeated here.
[0051]
That is, the casting mold 2A of this embodiment includes a
substantially cylindrical casting mold body 2A1. The casting mold
body 2A1 includes a circumferential groove 2A1(a) that is formed
on the inner peripheral surface thereof. An insulating film 2A2 is
formed on the inner surface (the peripheral surface and the
bottoms) of this groove, and an embedded layer 2A3 is formed by
embedding the same conductive material as the casting mold body
2A1 on the insulating film 2A2. An insulating layer portion is
formed of the insulating film 2A2 and the embedded layer 2A3.
The insulating layer portion is formed on a part of the inner surface
of the casting mold, and functions as a portion that does not allow
the flow of current from the casting mold.
[0052]
This insulating layer portion is formed on a slightly lower
portion of the inner surface of the casting mold body 2A1.
Accordingly, current is hardly allowed to flow to the cast
product P from the insulating layer portion of the casting mold
body 2A1, that is, a portion adjacent to the cast product P.
[0053]
In addition, a terminal 2A4 is provided on the outer
periphery of the casting mold body 2A1. Power can be supplied to
the casting mold 2A from the power supply 34 through this
terminal 2A4.
[0054]
CA 02829183 2013-09-05
17
When a voltage is applied between the terminal 2A4 and the
electrode 32B by the power supply 34 in the device having this
structure, current flows in the casting mold body 2A1, the melt M,
and the cast product P. Since current does not flow in the
insulating film 2A2 and the embedded layer 2A3 at this time, larger
current flows in the melt M. Accordingly, a larger electromagnetic
force, which allows the melt M to be agitated, is obtained.
[0055]
Fig. 6 illustrates still another embodiment.
[0056]
This embodiment is a modification of the embodiment of Fig.
1(a).
[0057]
This embodiment is different from the embodiment of Fig.
1(a) in the disposition of the upper electrodes 32A of Fig. 1(a).
That is, in this embodiment, one electrode 32A0 is disposed or a
plurality of electrodes 32A0 are disposed annularly, these
electrodes 32A0 are supported by arbitrary units other than the
casting mold 2A and the like (the casting mold 2A and the water
jacket 23), and a lower end portion of each of the electrodes 32A0
is inserted into the melt M. Accordingly, it is possible to adjust the
length of the lower end portion, which is inserted into the melt M,
of the electrode 32A0 with large degree of freedom regardless of
the casting mold 2A and the like. Moreover, obviously, a normal
mold may be used as the casting mold 2A or the like, and electrode
insertion holes 2a for electrodes 32A1 do not need to be formed in
the casting mold 2A or the like. Therefore, it is also possible to
prevent the increase in the manufacturing costs of these.
[0058]
Other structures are the same as the embodiment of Fig.
1(a).
[0059]
Fig. 7 illustrates yet another embodiment.
[0060]
This embodiment may be regarded as a modified example of
the embodiment of Fig. 6.
,
CA 02829183 2013-09-05
= ,
18
[0061] .
The embodiment of Fig. 7 is assumed as a device that can
be operated when melt M is poured into a casting mold 2A, which is
provided on the lower side, from a tundish (melt receiving box) 1A,
which is provided on the upper side, as continuous melt with no
interruption. That is, it is assumed that the melt M present in the
tundish (melt receiving box) 1A and the melt M present in the
casting mold 2A are integrally connected to each other.
[0062]
In Fig. 6, the electrodes 32A0 are inserted into the melt M
present in the casting mold 2. However, in Fig. 7, an electrode
32A1 is supported by arbitrary units so as to be inserted into the
melt M present in the tundish (melt receiving box) 1A on the
premise of the above-mentioned case. Accordingly, it is possible
to obtain the same advantage as the above-mentioned
embodiment of Fig. 6. In addition, it is possible to set and adjust
a distance between the tundish (melt receiving box) 1A and the
casting mold 2A or the like regardless of the electrode 32A1.
[0063]
Other structures are substantially the same as Fig. 6.
[0064]
Figs. 8(a) to 8(d), Figs. 9(a) to 9(c), and Fig. 10 illustrate
other embodiments of the invention, respectively.
[0065]
The same members of these embodiments as the members
of the above-mentioned embodiment are denoted by the same
reference numerals and the description thereof will not be
repeated.
[0066]
In these embodiments, a water jacket for cooling does not
need to be separately provided, a water flow chamber 22a(2),
which functions as both a cooling chamber and a magnetic field
generation device receiving chamber, is formed in the side wall of a
casting mold 2, that is, the side wall of the outer casting mold 22,
and a magnetic field generation device 31 as a permanent magnet
is received in the water flow chamber 22a(2) so that the position of
CA 02829183 2013-09-05
19
the magnetic field generation device can be adjusted in the vertical
direction.
[0067]
Meanwhile, a magnetic field generation device receiving
space (magnetic field generation device receiving chamber) 22a(2)
illustrated in Fig. 8(c) may be divided so as to receive a plurality of
permanent magnet pieces 31A, which are illustrated in Fig. 8(d)
and disposed at a predetermined interval, respectively. For
example, the magnetic field generation device receiving space may
be formed of a plurality of partial magnetic field generation device
receiving chambers having an arc-shaped cross-section.
[0068]
First, a device of manufacturing a billet of the embodiment
illustrated in Figs. 8(a) to 8(e) will be described.
[0069]
That is, as understood from Fig. 8(a), the outer casting
mold 22 includes a water flow chamber 22a(2) that is opened
downward and has a ring-shaped cross-section, and the water flow
chamber 22a(2) is hermetically-sealed by a lid 22B(1). Fig. 8(b) is
a view illustrating the inner casting mold 21 and the outer casting
mold 22 taken along line VIII(b) - VIII(b) from below when the lid
22B(1) is removed. This lid 22B(1) forms a part of the casting
mold 2.
[0070]
As understood from Fig. 8(a), a magnetic field generation
device 31, which is formed of a plurality of permanent magnet
pieces 31A (Fig. 8(c)) having an arc-shaped cross-section, is
received in the ring-shaped water flow chamber 22a(2) serving as
a magnetic field generation device receiving space (receiving
chamber) so as to be capable of being adjusted in the vertical
direction. That is, the water flow chamber (cooling chamber)
22a(2) functions as both a cooling water flow chamber and a
magnetic field generation device receiving chamber. A plan view
of these permanent magnet pieces 31A is illustrated in Fig. 8(d).
The inner portion of each of the permanent magnet pieces 31A is
magnetized to an N pole and the outer portion thereof is
CA 02829183 2013-09-05
magnetized to an S pole. ,The magnetization may be contrary to
this. That is, the magnetic field generation device 31 is provided
so that the height of the magnetic field generation device can be
adjusted in the water flow chamber 22a(2) by arbitrary units (not
5 illustrated). Accordingly, it is possible to more efficiently agitate
the melt M by adjusting the height of the magnetic field generation
device so as to correspond to liquid-phase melt M as described
above.
[0071]
10 The lower opening of the water flow chamber 22a(2) is
closed by the above-mentioned ring-shaped lid 22B. A plan view
of the lid 22B is illustrated in Fig. 8(e). As understood from Figs.
8(e) and 8(a), a plurality of discharge channels 22B(1) for cooling
water are formed in the lid 22B(1). As understood from Figs. 8(a)
15 and 8(e), the plurality of discharge channels 22B(1) include a
plurality of inlets 22B(1)a1 that are opened to the upper surface of
the lid 22B, and include outlets 22B(1)a2 on the peripheral surface
of the lid 22B. Accordingly, cooling water present in the water flow
chamber 22a(2) enters from the plurality of inlets 22B(1)a1, flows
20 out of the outlets 22B(1)a2, and is jetted to the outer periphery of
the product P to cool the product P. That is, cooling water enters
the water flow chamber 22a(2) from inlets (not illustrated), is
circulated in the water flow chamber while cooling the product, and
is discharged while being jetted to the outside from the discharge
channels 22B(1).
[0072]
Since the operation of the above-mentioned device of Figs.
8(a) to 8(e) is the same as that of the above-mentioned
embodiment, the description thereof will not be repeated.
[0073]
Meanwhile, the magnetic field generation device 31 has
been formed of the plurality of permanent magnet pieces 31A in
the above-mentioned embodiment of Figs. 8(a) to 8(e). However,
it is obvious that the magnetic field generation device may be
integrally formed as in Fig. 3(a). Further, the water flow chamber
22a(2) serving as the magnetic field generation device receiving
CA 02829183 2013-09-05
21
space is formed in a circumferential shape as understood from Fig.
8(b). However, the water flow chamber is not limited to this shape,
and may be formed of a plurality of cell chambers that are divided
in the circumferential direction and have an arc-shaped
cross-section. It is preferable that cooling water can flow in each
cell chamber and the permanent magnet piece 31A be received in
each cell chamber so as to be capable of moving up and down.
[0074]
In the device of Figs. 8(a) to 8(e), the magnetic field
generation device 31 is not provided outside the casting mold 2,
and a cavity (water flow chamber 22a(2)) is formed in the casting
mold 2 (outer casting mold 22) and the magnetic field generation
device 31 is received in the cavity. Accordingly, it is possible to
obtain the following characteristics.
[0075]
- A permanent magnet, which is small and has a small
capacity, may be used as the magnetic field generation device 31.
That is, if the magnetic field generation device 31 is
provided outside the casting mold, it is inevitable that a distance
between the magnetic field generation device 31 and the melt M is
slightly increased. However, since the magnetic field generation
device is built in the casting mold 2 in this embodiment, the
distance between the magnetic field generation device 31 and the
melt M is reduced. Accordingly, a permanent magnet, which is
small and has a small capacity, may be used to obtain the same
agitating performance.
[0076]
- It is possible to significantly improve a working property.
That is, when this device is operated, a plurality of
inspectors should be positioned around the device to perform
various kinds of measurement, nondestructive inspection, and the
like and should perform such the measurement and the like for the
check of a product P. However, in the case of the magnetic field
generation device that is provided outside, the increase in size and
volume cannot be avoided and it cannot be denied that it is difficult
to perform such the measurement since a strong magnetic field is
CA 02829183 2013-09-05
22
generated. However, since the magnetic field generation device 31
is provided in the casting mold 2 in this embodiment, a volume is
not increased and the intensity of a magnetic field emitted to the
outside is reduced. For this reason, it is easy to perform various
kinds of measurement and the like.
[0077]
- It is possible to significantly improve productivity.
That is, it is possible to reduce time required for the
above-mentioned measurement and the like. As a result, it is
possible to increase the manufacturing rate of a product P per unit
time.
[0078]
- It is possible to reduce size.
That is, since the magnetic field generation device 31 is a
built-in type, it is possible to provide a device that is small as a
whole as much as that.
[0079]
- It is possible to save a space of an installation location.
That is, since the magnetic field generation device 31 is a
built-in type when the device is regarded as a device
manufacturing the same product P although being the same as
described above, the size of the device is reduced as a whole.
Accordingly, it is possible to install the device even at a narrow
place. As a result, flexibility is obtained in the usefulness of the
device.
[0080]
The above-mentioned effects will be described below from a
different standpoint.
[0081]
When a product P is manufactured by this device, for
example, five or six workers gather around the device and should
perform high-density works (works for monitoring and preventing
the leakage of melt, works for monitoring and preventing the jet of
melt, and the like) in a short time. When these works are
performed by a plurality of workers, a working property is good in
the built-in type device of this embodiment as compared to a case
CA 02829183 2013-09-05
=
23
where the magnetic field generation device 31 is provided outside
so as to protrude. That is, since the external appearance of the
device has the same dimensions as the dimensions of a device that
does not include the magnetic field generation device 31 that is a
device in the related art, the device of this embodiment is very
easy to use at the work site.
[0082]
Further, it is preferable that the magnetic field generation
device 31 be close to the melt M as much as possible in order to
reliably apply a magnetic field to the melt M, and this is realized in
a built-in type.
[0083]
When the magnetic field generation device 31 is provided
outside, the influence of a magnetic field on various measuring
instruments such as temperature sensors should be considered.
However, since the influence thereof is reduced in a built-in type, a
built-in type is more advantageous in measurement. That is,
when a product P, such as a slab or a billet, is manufactured, the
measurement, management, and the like of temperature in several
positions are very important to maintain the quality of a product.
This embodiment is very advantageous in the measurement of
temperature and the like.
[0084]
If a built-in type magnetic field generation device as in this
embodiment is used instead of the magnetic field generation device
provided outside, the size, weight, and volume of a device may be
reduced when the same magnetic field is applied to the melt M.
Accordingly, the device is easy to use. That is, since the
respective components of this device are consumables, the
respective components of this device need to be replaced whenever
a predetermined operation time has passed. However, since the
magnetic field generation device 31 is small and light, a work for
replacing the magnetic field generation device and the like are very
easily performed.
[0085]
Since a work at the device of this embodiment is a work
= CA 02829183 2013-09-05
24
that is performed at a so-called high temperature of about 700 C,
the work is very dangerous for a worker. However, a magnetic
field generation device, which is small and of which the intensity of
a magnetic field is low, may be used as the magnetic field
generation device 31.
Further, a tool, which is used for the
adjustment, maintenance, and the like of the device, is generally a
ferromagnetic body made of iron and safety shoes and the like are
also made of iron. However, if a magnetic field of the magnetic
field generation device 31, which is emitted by the outside, is
reduced a little, the safety of a security officer, a worker, a
measuring person, and the like is ensured.
[0086]
It is obvious that the effects described above with reference
to Figs. 8(a) to 8(e) are mentioned in not only the device of Fig. 1
and the like but also devices for manufacturing a slab that are to
be described below and illustrated in Figs. 9(a) to 9(c) and 10.
[0087]
Figs. 9(a) to 9(c) illustrate a device for manufacturing a slab.
However, the basic technical idea of the device is the same as
described above except that a billet has a circular shape and a slab
has a rectangular shape. Accordingly, the same members are
denoted by the same reference numerals and the description
thereof will not be repeated.
[0088]
A difference will be described below.
[0089]
The weight of a slab as a product P is very heavy. For this
reason, a billet can be pulled in the horizontal direction, but a slab
as a product P is not obtained unless taken out in the vertical
direction.
For this reason, a pedestal 51 is prepared, and a
product P is taken out while riding the pedestal 51 and being
gradually pulled downward. A lower electrode 32B is embedded in
the pedestal 51.
A magnetic field generation device 31 is
illustrated in Figs. 9(b) and 9(c). Fig. 9(b) is a cross-sectional
view taken along line IX(b) - IX(b) of Fig. 9(a), and Fig. 9(c) is a
plan view of the magnetic field generation device 31. Here, the
CA 02829183 2013-09-05
magnetic field generation device. 31 uses four permanent magnet
pieces 31A and forms two pairs facing each other, but may use any
one pair.
[0090]
5 Fig. 10 illustrates a modified example of Fig. 9(a).
[0091]
In Fig. 10, a pair of electrodes 32A and 32B is used while
being inserted into melt M. The
inventor confirmed by an
experiment that the melt M is agitated even though the electrodes
10 32A and 32B are used in this way. That is, even though the pair of
electrodes 32A and 32B is employed as illustrated in Fig. 10, the
magnetic lines of force generated from a magnetic field generation
device 31 and current flowing between the pair of electrodes 32A
and 32B flow in various paths in the melt M and generate an
15 electromagnetic force according to Fleming's rule.
