TECHNICAL FIELD
[0001] The present disclosure relates to a casting equipment and a casting method, and more
particularly, to a casting equipment and a casting method, which are capable of controlling
a flow of a molten material to secure a cleanliness of the molten material, thereby
improving a quality of a product,.
BACKGROUND ART
[0002] In general, a continuous casting process may produce various shaped cast slabs such
as a slab, a bloom, a billet, and a beam blank by injecting molten steel into a mold
having a predetermined inner shape and continuously drawing a semi-solidified cast
slab downward from the mold. The cast slab produced as described above has a surface
quality and an inner quality, which are affected by various factors. Particularly,
the surface quality of the cast slab is highly affected by a flow of the molten steel
in the mold.
[0003] When a molten material is injected into a mold by using a submerged entry nozzle
in the continuous casting process, the molten material discharged from a discharge
hole of the submerged entry nozzle forms a jet stream to flow in a width direction
of the mold. The molten material flowing in the width direction of the mold collides
an inner surface of the mold, e.g., an inner surface of a short side plate, so that
a portion of the molten material forms an upflow, and a portion thereof forms a downflow.
The upflow moves to a central portion of the mold around a molten surface of the molten
material, e.g., a portion at which the submerged entry nozzle is installed. The molten
material moving toward the central portion of the mold collides with the molten material
moving in an opposite direction and the submerged entry nozzle to form a vortex at
the molten surface around the submerged entry nozzle, thereby causing instability
of the flow of the molten surface. Here, the instability of the flow of the molten
surface becomes worse as a flow velocity of the upflow increases and causes a different
kind of material such as mold slag or mold flux disposed at an upper portion of the
molten surface of the molten material to be mixed into the molten material.
[0004] Also, the downflow flows downward along an edge of the mold to form a secondary upflow
moving upward at the central portion of the mold. Here, as the inclusions contained
in the molten steel moves along a casting direction with the downflow and floats with
the secondary upflow, the inclusions may flow into the mold slag or the mold flux
and be removed together. However, when the movement distance of the inclusion is changed
according to a flow velocity of the downflow, and the downflow has a fast flow velocity,
the inclusion is permeated to a solidified cell and causes a surface defect of the
produced cast slab.
[0005] To resolve the above-described limitation, a method of controlling the flow of the
molten steel in the mold by installing a magnetic field generator in the mold is used.
By using this method, the mold flux is restricted from flowing into the molten steel
by controlling the upflow around the molten surface of the molten steel, and the movement
distance of the inclusion is controlled by controlling the downflow below the submerged
entry nozzle to restrict the surface defect of the cast slab from being generated.
However, in the process of controlling the downflow, formation of the secondary upflow
generated by the downflow is also restricted. Accordingly, the inclusion moving in
the casting direction with the downflow is remained in the molten steel instead of
floating properly to cause degradation in quality of the cast slab.
(Related art document 1)KR10-1176816 B
(Related art document 2) JP4411945 B
DISCLOSURE OF THE INVENTION
TECHNICAL PROBLEM
[0006] The present disclosure provides a casting equipment capable of controlling a flow
of a molten material and a casting method.
[0007] The present disclosure also provides a casting equipment capable of smoothly removing
an inclusion contained in a molten material and restricting a different kind of material
from being mixed into the molten material to improve a quality of a product and a
casting method.
TECHNICAL SOLUTION
[0008] In accordance with an exemplary embodiment, a casting equipment for casting a cast
slab includes: a mold configured to provide an inner space for accommodating a molten
material; a nozzle disposed above the mold to supply the molten material into the
mold; a static magnetic field generation unit disposed on an outside in a width direction
of the mold so that magnetic fields at both edges in the width direction of the mold
are controlled in different directions; and a control unit configured to control an
operation of the static magnetic field generation unit.
[0009] The mold may include one pair of long side plates spaced apart from each other and
one pair of short side plates configured to connect both sides of each of the one
pair of long side plates, and the static magnetic field generation unit may include:
a plurality of static magnetic field generators disposed in a width direction of the
long side plate below the nozzle so as to be spaced apart from a central portion in
the width direction of the mold; and a first current supplier configured to supply
a direct current to the plurality of static magnetic field generators so as to form
a magnetic field passing in a thickness direction of the mold at both sides of the
nozzle in the width direction of the mold.
[0010] Each of the plurality of static magnetic field generators may include: a core extending
along a portion of the width direction of the long side plate and spaced apart from
another core; and a coil wound around an outside of the core.
[0011] The plurality of static magnetic field generators may include: a first static magnetic
field generator; a second static magnetic field generator disposed at one side of
the first static magnetic field generator while being spaced apart therefrom so that
the nozzle is disposed therebetween; a third static magnetic field generator disposed
to face the second static magnetic field generator; and a fourth static magnetic field
generator disposed at one side of the third static magnetic field generator while
being spaced apart therefrom so that the nozzle is disposed therebetween and disposed
to face the first static magnetic field generator, and the first current supplier
may supply a direct current to the first static magnetic field generator, the second
static magnetic field generator, the third static magnetic field generator, and the
fourth static magnetic field generator so as to form opposite polarities in directions
facing each other in the thickness direction of the mold and opposite polarities in
the width direction of the mold.
[0012] The first static magnetic field generator and the second static magnetic field generator
may be spaced by a first distance from each other, and the third static magnetic field
generator and the fourth static magnetic field generator may be spaced by a second
distance from each other. Here, the first distance may be the same as the second distance.
[0013] When the cast slab has an entire width of 100, each of the first distance and the
second distance may be in a range from 4 to 36.
[0014] At least one of the first static magnetic field generator, the second static magnetic
field generator, the third static magnetic field generator, and the fourth static
magnetic field generator may be movable along the width direction of the mold.
[0015] The casting equipment may further include: a first connection core configured to
connect the first static magnetic field generator and the second static magnetic field
generator; and a second connection core configured to connect the third static magnetic
field generator and the fourth static magnetic field generator.
[0016] The static magnetic field generation unit may form a magnetic field that rotates
in a circumferential direction of the mold.
[0017] The casting equipment may further include a dynamic magnetic field generation unit
disposed above the static magnetic field generation unit to form a dynamic magnetic
field for controlling a flow of the molten material, and the control unit may control
an operation of the dynamic magnetic field generation unit so as to adjust at least
one of an intensity and a direction of the dynamic magnetic field.
[0018] The dynamic magnetic field generation unit may include a plurality of dynamic magnetic
field generators configured to form a dynamic magnetic field at both sides of the
nozzle in the width direction of the mold.
[0019] The dynamic magnetic field generation unit may be disposed in parallel to the static
magnetic field generation unit and control the flow of the molten material in a direction
different from the static magnetic field generation unit.
[0020] In accordance with another exemplary embodiment, a casting method includes: injecting
a molten material into a mold by using a nozzle; forming a static magnetic field applied
region and a non-static magnetic field applied region in a width direction of the
mold and controlling a flow of the molten material in a longitudinal direction of
the mold;
and drawing a cast slab.
[0021] The casting method may further include, before the injecting of the molten material,
arranging the nozzle at a central portion in the width direction of the mold, and
the controlling of the flow of the molten material may include forming the non-static
magnetic field applied region at a central portion in the width direction of the mold
and forming the static magnetic field applied region at both sides of the non-static
magnetic field applied region.
[0022] The controlling of the flow of the molten material may include forming the static
magnetic field applied region and the non-static magnetic field applied region below
the nozzle.
[0023] The controlling of the flow of the molten material may include forming a magnetic
field along a thickness direction of the mold, and the forming of the static magnetic
field applied region may include forming a static magnetic field so that magnetic
fields at both sides of the nozzle have opposite directions.
[0024] The controlling of the flow of the molten material may include forming the non-static
magnetic field applied region at a portion of the central portion in the width direction
of the mold, at which the nozzle is disposed.
[0025] The controlling of the flow of the molten material may include controlling a range
of the static magnetic field applied region so that the non-static magnetic field
applied region has a magnetic field of 0 Gauss to 100 Gauss.
[0026] The controlling of the flow of the molten material may include adjusting a distance
between the static magnetic field applied regions according to a width of the cast
slab.
[0027] The controlling of the flow of the molten material may include forming the static
magnetic field applied region at both edges in the width direction of the mold to
reduce a flow velocity of a downflow of the molten material and forming the non-static
magnetic field applied region between the static magnetic field applied regions to
form an upflow of the molten material.
[0028] The controlling of the flow of the molten material may further include forming a
dynamic magnetic field applied region and a non-dynamic magnetic field applied region
to control the flow of the molten material in the width direction of the mold.
[0029] The controlling of the flow of the molten material in the width direction of the
mold may include forming a dynamic magnetic field applied region and a non-dynamic
magnetic field applied region between a molten surface of the molten material and
a lower end of the nozzle.
[0030] The forming of the dynamic magnetic field applied region may include forming a dynamic
magnetic field in the width direction of the mold at both sides of the nozzle in the
width direction of the mold.
[0031] The forming of the dynamic magnetic field applied region may include adjusting at
least one of an intensity and a direction of the dynamic magnetic field.
ADVANTAGEOUS EFFECTS
[0032] In accordance with the exemplary embodiment, the flow of the molten material in the
container may be locally controlled. That is, the flow of the molten material in the
longitudinal direction of the mold may be selectively controlled by selectively applying
the static magnetic field in the width direction of the mold. Thus, the inclusion
contained in the molten material may have the reduced downward movement distance along
the molten material and simultaneously easily float upward to restrict the quality
degradation of the product caused by the inclusion. Also, as the dynamic magnetic
field is formed in the width direction of the mold, the flow of the molten material
around the molten surface of the molten material may be controlled to restrict the
different kind of material such as the mold flux or the mold slag from being mixed
with the molten material. Through this, the cleanliness of the molten material may
be secured, and the quality of the product manufactured by using the molten material
may be improved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033]
FIG 1 is a perspective view illustrating a casting equipment in accordance with an
exemplary embodiment.
FIG 2 is a cross-sectional view illustrating the casting equipment taken along line
A-A' of FIG 1.
FIG 3 is a view for explaining a principle of controlling a flow of a molten material
by using a static magnetic field generator.
FIG 4 is a cross-sectional view illustrating a casting equipment in accordance with
a modified example.
FIG 5 is a view illustrating a state of controlling a flow of a molten material by
a casting method in accordance with an exemplary embodiment.
FIG. 6 is a view illustrating a flow analysis result of a secondary upflow in a mold
according to whether a non-static magnetic field applied region is formed in a width
direction of the mold.
FIG. 7 is a cross-sectional view illustrating the casting equipment taken along line
B-B' of FIG 1.
FIG. 8 is a view illustrating an example of controlling a flow of a molten material
by using a dynamic magnetic field generator.
MODE FOR CARRYING OUT THE INVENTION
[0034] Hereinafter, specific embodiments will be described in more detail with reference
to the accompanying drawings. The present invention may, however, be embodied in different
forms and should not be construed as limited to the embodiments set forth herein.
Rather, these embodiments are provided so that this disclosure will be thorough and
complete, and will fully convey the scope of the present invention to those skilled
in the art. In every possible case, like reference numerals are used for referring
to the same or similar elements in the description and drawings. In the figures, the
dimensions of layers and regions are exaggerated for clarity of illustration. Like
reference numerals in the drawings denote like elements, and thus their description
will be omitted.
[0035] FIG. 1 is a perspective view illustrating a casting equipment in accordance with
an exemplary embodiment, and FIG. 2 is a cross-sectional view taken along line A-A'
of FIG. 1.
[0036] Referring to FIGS. 1 and 2, the casting equipment in accordance with an exemplary
embodiment may include: a mold 100 providing a space for accommodating a molten material
therein; a nozzle 130 having at least a portion inserted into the mold 100 to supply
the molten material to the mold 100; a static magnetic field generation unit 200 provided
on an outside in a width direction of the mold 100 to control a direction of a magnetic
field in different directions at both edges in the width direction of the mold 100;
and a control unit 400 capable of controlling an operation of the static magnetic
field generation unit 200.
[0037] The mold 100 may include a plurality of plates 110 and 120 for providing a space
for accommodating a molten material, e.g., molten steel, therein. Here, the plurality
of plates 110 and 120 may include long side plates 110 and short side plates 120.
[0038] The long side plates 110, e.g., a first long side plate 111 and a second long side
plate 113, may be spaced apart from each other to face each other, and the short side
plates 120, e.g., a first short side plate 121 and a second short side plate 123,
may contact both sides of each of the first long side plate 111 and the second long
side plate 113 to form a space for accommodating a molten material therein. Here,
upper and lower portions of the mold 100 may be opened, and the long side plates 110
and the short side plates 120 may closely contact each other to prevent the molten
material from being leaked through a contact portion thereof.
[0039] Here, a length in a horizontal direction of each of the long side plates 110 is referred
to as a width the of long side plate 110, and a direction of the width is referred
to as a width direction of the long side plate 110. Here, the width direction of the
long side plate 110 may represent a width direction of the mold 100. Here, a length
in a vertical direction of the long side plate 110 is referred to as a length the
of long side plate 110, and a direction of the length is referred to as a longitudinal
direction of the long side plate 110. Here, the longitudinal direction of the long
side plate 110 may represent a longitudinal direction of the mold 100 or a drawing
direction of a cast slab. Also, a length in a horizontal direction of each of the
short side plates 120 is referred to as a width the of short side plate 120, and a
direction of the width is referred to as a width direction of the short side plate
120. Here, the width direction of the short side plate 120 may represent a width direction
of the mold 100.
[0040] As a flow path (not shown) through which a cooling medium moves is formed in each
of the long side plate 110 and the short side plate 120, the molten material injection
to the mold may be cooled by the cooling medium moving along the flow path. Thus,
the molten material may be solidified from a portion contacting an inner surface of
the mold 100 to be cast into a solidified cell or a cast slab, and drawn to a lower
portion of the mold 100.
[0041] The nozzle 130 may be disposed at an upper portion of the mold 100 to inject the
molten material into the mold 100. The nozzle 130 may have at least a portion, e.g.,
a lower portion, inserted into the mold 100 to inject the molten material accommodated
in a tundish (not shown) disposed above the mold 100 into the mold 100. The nozzle
130 may include a nozzle body 132 having an inner empty part through which the molten
material moves and a discharge hole 134 through which the molten material moves from
the inner hole part to the outside, i.e., the mold 100. Here, the nozzle body 132
may have an opened upper portion and a closed lower end, and the inner empty part
(not shown) may be defined in the nozzle body 132 to form a path through which the
molten material moves. Also, at least two discharge holes 134, e.g., two or four discharge
holes, may be defined in a lower side surface of the nozzle body 132 to discharge
the molten material into the mold 100. Here, the discharge hole 134 may be formed
in the lower side surface of the nozzle body 132, which faces the short side plate
120, to discharge the molten material in the width direction of the mold 100.
[0042] The static magnetic field generation unit 200 may be disposed at an outside in the
width direction of the mold 100 and apply a magnetic field, e.g., a static magnetic
field, to the molten material. Here, the static magnetic field generation unit 200
may be disposed below a lower end of the nozzle 130 to control a flow of a downflow
of the molten material discharged from the discharge hole 134. Also, the static magnetic
field generation unit 200 may be formed at each of both edges in the width direction
of the mold 100, in which the downflow is formed, to form a static magnetic field
applied region. The static magnetic field generation unit 200 may apply a static magnetic
field in the width direction of the mold 100 to reduce a flow velocity of the downflow
of the molten material, which is formed at the edge in the width direction of the
mold 100. Here, the static magnetic field may be formed by using a direct current
power in a magnetic field generator and reduce a flow velocity of fluid by restricting
an overall movement or flow of fluid in a magnetic field region. When the static magnetic
field is applied by the static magnetic field generation unit 200, a movement of the
downflow may be restricted by the static magnetic field to reduce the flow velocity
of the downflow. Thus, as a movement distance of an inclusion in a downward direction
is reduced, a penetration depth of the inclusion in the molten material may decrease.
[0043] Even in the related art, a method of controlling the downflow by installing the static
magnetic field generation unit in the mold is used. In this case, since the static
magnetic field generation unit is installed in the mold to apply the static magnetic
field along the entire width direction of the mold, the flow velocity of the downflow
may be reduced. However, as the flow of the molten material is restricted by the magnetic
field formed along the entire width direction of the mold, a secondary upflow may
be also reduced to allow the inclusion contained in the molten material to float upward.
[0044] Thus, in accordance with an exemplary embodiment, as a static magnetic field applied
region and a non-static magnetic field applied region are selectively formed along
the width direction of the mold 100 by using the static magnetic field generation
unit 200, the flow velocity of the downflow may be reduced by using the static magnetic
field in the static magnetic field applied region, and the secondary upflow may be
formed by minimizing an effect of the static magnetic field in the non-static magnetic
field applied region.
[0045] The static magnetic field generation unit 200 may form the static magnetic fields
at both sides in the width direction of the mold 100 in different directions, e.g.,
opposite directions, in a thickness direction of the mold 100. Thus, the static magnetic
field generation unit 200 may form the static magnetic field applied region at both
the edge in the width direction of the mold 100 and form a region in which an intensity
of the magnetic field formed in the static magnetic field applied region is offset,
i.e., the non-static magnetic field applied region, at a central portion in the width
direction of the mold 100. Thus, since an inclusion having a reduced penetration depth
in the static magnetic field applied region may easily float upward by the secondary
upflow formed in the non-static magnetic field applied region, a defect of a surface
of the cast slab caused by the including may be restricted.
[0046] The static magnetic field generation unit 200 may reduce the flow velocity of the
downflow formed in the longitudinal direction of the mold at both the edges in the
width direction of the mold 100, in which the static magnetic field applied region
is formed, and increase the flow velocity of the secondary upflow formed in the longitudinal
direction of the mold or allow the secondary upflow to be smoothly formed at the central
portion in the width direction of the mold 100, in which the non-static magnetic field
applied region is formed.
[0047] Here, the static magnetic field applied region, as a region in which the static magnetic
field or the magnetic field is formed by the static magnetic field generation unit
200, may represent a region in which the static magnetic field or the magnetic field
having an intensity capable of causing the flow of the molten material is applied.
Also, the non-static magnetic field applied region may represent a region in which
the static magnetic field or the magnetic field having an intensity that is not affected
to the flow of the molten material is applied or a region in which the static magnetic
field or the magnetic field is not applied at all. For example, the non-static magnetic
field applied region may represent a region in which the static magnetic field or
the magnetic field having an intensity of 0 Gauss to 100 Gauss is applied.
[0048] Referring to FIG. 2, the static magnetic field generation unit 200 may include a
plurality of static magnetic field generators 210, 220, 230, and 240 disposed in the
width direction of the long side plate 110 below the lower end of the nozzle 130 and
a first direct current supplier 250 for supplying a direct current to the plurality
of static magnetic field generators 210, 220, 230, and 240.
[0049] The plurality of static magnetic field generators 210, 220, 230, and 240 may include
a first static magnetic field generator 210, a second static magnetic field generator
220 spaced apart from the first static magnetic field generator 210 so that the nozzle
130 is disposed between the first static magnetic field generator 210 and the second
static magnetic field generator 220, a third static magnetic field generator 230 disposed
to face the second static magnetic field generator 220, and a fourth static magnetic
field generator 240 spaced apart from the third static magnetic field generator 230
so that the nozzle 130 is disposed between the third static magnetic field generator
230 and the fourth static magnetic field generator 240 and disposed to face the first
static magnetic field generator 210. The first static magnetic field generator 210
and the second static magnetic field generator 220 may be spaced apart from each other
on an outer surface of the first long side plate 111, and the third static magnetic
field generator 230 and the fourth static magnetic field generator 240 may be spaced
apart from each other on an outer surface of the second long side plate 113. Here,
a spaced distance D between the first static magnetic field generator 210 and the
second static magnetic field generator 220, e.g., a first distance, may be the same
as a spaced distance D between the third static magnetic field generator 230 and the
fourth static magnetic field generator 240, e.g., a second distance. This allows the
non-static magnetic field applied region to be formed at the central portion in the
width direction of the mold 100. Each of the first distance and the second distance
may be varied based on a width of the cast slab to be cast. When an entire width of
the cast slab is 100, each of the first distance and the second distance may be adjusted
in a range from 4 to 36. Alternatively, when the entire width of the cast slab is
100, each of the first distance and the second distance may be adjusted in a range
from 10 to 25 or in a range from 15 to 20. Here, when each of the first distance and
the second distance is much less than the suggested range, a space for forming the
secondary upflow may be sufficiently secured. Since the secondary upflow is almost
not formed or formed in a relatively small region although the secondary upflow is
formed, the inclusion contained in the molten material may not be sufficiently removed.
On the other hand, when each of the first distance and the second distance is much
greater than the suggested range, the downflow having a reduced flow velocity may
not sufficiently move from both the edges in the width direction of the mold 100 to
the central portion of the mold 100, and accordingly the flow velocity of the secondary
upflow may be also reduced, so that the inclusion is difficult to float upward.
[0050] Thus, as each of the first static magnetic field generator 210, the second static
magnetic field generator 220, the third static magnetic field generator 230, and the
fourth static magnetic field generator 240 is movable in the width of the mold 100,
each of the first distance and the second distance may be appropriately adjusted based
on the width of the cast slab to effectively removing the inclusion contained in the
molten material. Here, the first distance and the second distance may be affected
by a casting speed. For example, when the width of the cast slab is 1100 mm or less,
and the casting speed is in a range from 0.7 m/min to 2.8 m/min, each of the first
distance and the second distance may be adjusted in a range from 50 mm to 250 mm.
Also, when the width of the cast slab is in a range from 1100 mm to 1500 mm, and the
casting speed is in a range from 0.7 m/min to 2.8 m/min, each of the first distance
and the second distance may be adjusted in a range from 100 mm to 350 mm, and when
the width of the cast slab is in a range from 1500 mm to 1900 mm, and the casting
speed is in a range from 0.7 m/min to 2.8 m/min, each of the first distance and the
second distance may be adjusted in a range from 100 mm to 500 mm
[0051] Firstly, the first static magnetic field generator 210 may be biased to one side
of the first long side plate 111, and the second static magnetic field generator 220
may be spaced apart from the first static magnetic field generator 210 and biased
to the other side of the first long side plate 111. Here, the first static magnetic
field generator 210 may include a first core 212 and a first coil 214 wound around
an outside of the first core 212. The second static magnetic field generator 220 may
include a second core 222 and a second coil 224 wound around an outside of the second
core 222. Here, one side of the mold 100 or one side of the long side plate 110 may
represent a direction in which the first short plate 121 is disposed, and the other
side of the mold 100 or the other side of the long side plate 110 may represent a
direction in which the second short plate 123 is disposed.
[0052] The first core 212 and the second core 222 may be disposed on an outside of the mold
100 and spaced apart from each other in the width direction of the mold 100. Each
of the first core 212 and the second core 222 may have a plate shape extending in
one direction. For example, each of the first core 212 and the second core 222 may
have a plate shape in which a length in the width direction of the mold 100 is greater
than that in the thickness direction of the mold 100. The first core 212 and the second
core 222 may be arranged in a row on an outer surface of the first long side plate
111 to each extend along a portion of the width direction of the first long side plate
111. Here, the first core 212 and the second core 222 may be spaced apart from the
central portion in the width direction of the mold 100 in which the nozzle 130 is
disposed so that the nozzle 130 is disposed therebetween.
[0053] Also, the first coil 214 may be wound around the outside of the first core 212 in
a direction in which the first core 212 extends, e.g., the width direction of the
mold 100. Also, the second coil 224 may be wound around the outside of the second
core 222 in a direction in which the second core 222 extends, e.g., a horizontal direction
in the width direction of the mold 100.
[0054] Also, the third static magnetic field generator 230 may be biased to the other side
of the second long side plate 113, and the fourth static magnetic field generator
240 may be spaced apart from the third static magnetic field generator 230 and biased
to the one side of the second long side plate 113. Here, the third static magnetic
field generator 230 may be disposed at a position facing the second static magnetic
field generator 220, e.g., disposed to face the second static magnetic field generator
220, and the fourth static magnetic field generator 240 may be disposed to face the
first static magnetic field generator 210. The third static magnetic field generator
230 may include a third core 232 and a third coil 234 wound around an outside of the
third core 232. The fourth static magnetic field generator 240 may include a fourth
core 242 and a fourth coil 244 wound around an outside of the fourth core 242. The
third core 232 and the fourth core 242 may be disposed on an outside of the mold 100
and spaced apart from each other in the width direction of the mold 100. The third
core 232 and the fourth core 242 may be arranged in a row on an outer surface of the
second long side plate 113 to each extend along a portion of a width direction of
the second long side plate 113. Here, the third core 232 and the fourth core 242 may
be spaced apart from the central portion in the width direction of the mold 100 in
which the nozzle 130 is disposed so that the nozzle 130 is disposed therebetween.
[0055] Also, the third coil 234 may be wound around the outside of the third core 232 in
the width direction of the mold 100 that is a direction in which the third core 232
extends. Also, the fourth coil 244 may be wound around the outside of the fourth core
222 in the width direction of the mold 100 that is a direction in which the fourth
core 242 extends.
[0056] The first static magnetic field generator 210, the second static magnetic field generator
220, the third static magnetic field generator 230, and the fourth static magnetic
field generator 240 may be electrically connected with the first direct current supplier
250. The first direct current supplier 250 may supply a direct current to the first
static magnetic field generator 210, the second static magnetic field generator 220,
the third static magnetic field generator 230, and the fourth static magnetic field
generator 240. The first direct current supplier 250 may supply the direct current
simultaneously or selectively to the first static magnetic field generator 210, the
second static magnetic field generator 220, the third static magnetic field generator
230, and the fourth static magnetic field generator 240 through control of the control
unit 400. The first direct current supplier 250 may supply the direct current to each
of the first static magnetic field generator 210, the second static magnetic field
generator 220, the third static magnetic field generator 230, and the fourth static
magnetic field generator 240 so that a magnetic field direction is formed in the thickness
direction of the mold 100. Here, the first direct current supplier 250 may supply
the direct current so that the magnetic field directions are formed in opposite directions
at the central portion in the width direction of the mold 100, e.g., at both the sides
of the nozzle 130. That is, the first direct current supplier 250 may supply the direct
current to the first static magnetic field generator 210, the second static magnetic
field generator 220, the third static magnetic field generator 230, and the fourth
static magnetic field generator 240 so that the magnetic field direction is formed
from the first static magnetic field generator 210 to the fourth static magnetic field
generator 240 at the one side of the mold 100, and the magnetic field direction is
formed from the third static magnetic field generator 230 to the second static magnetic
field generator 220 at the other side of the mold 100. Here, the control unit 400
may control the first direct current supplier 250 to adjust a current amount supplied
to each of the first static magnetic field generator 210, the second static magnetic
field generator 220, the third static magnetic field generator 230, and the fourth
static magnetic field generator 240 in order to adjust an intensity or a strength
of the magnetic field.
[0057] Here, the magnetic field direction formed at one side of the nozzle 130 in the width
direction of the mold 100, e.g., the one side of the mold 100, is referred to as a
first direction, and the magnetic field direction formed at the other side of the
nozzle 130 in the width direction of the mold 100, e.g., the other side of the mold
100, is referred to as a second direction. For example, the magnetic field direction
formed between the first static magnetic field generator 210 and the fourth static
magnetic field generator 240 is referred to as the first direction, and the magnetic
field direction formed between the second static magnetic field generator 220 and
the third static magnetic field generator 230 is referred to as the second direction.
Here, the first direction and the second direction may be opposite to each other.
Also, in each of the first core 212, the second core 222, the third core 232, and
the fourth core 242, a direction facing the mold 100 is referred to as one side, and
a direction facing the outside of the mold 100 is referred to as the other side. Thus,
the first current supplier 250 may supply the direct current so that one side of the
first core 212 and one side of the fourth core 242, which face each other, have opposite
polarities. Also, the first current supplier 250 may supply the direct current so
that one side of the second core 222 and one side of the third core 232, which face
each other, have opposite polarities. Here, the first current supplier 250 may supply
the direct current so that so that one side of the first core 212 and one side of
the second core 222 have opposite polarities, and one side of the third core 232 and
one side of the fourth core 242 have opposite polarities.
[0058] For example, the first current supplier 250 may supply the direct current so that
each of one side of the first core 212 and one side of the third core 232 has an N
pole, and each of one side of the second core 222 and one side of the fourth core
242 has a S pole. In this case, when the first current supplier 250 supplies the direct
current to each of the static magnetic field generators 210, 220, 230, and 240, a
static magnetic field may be formed in each of the static magnetic field generators
210, 220, 230, and 240. The static magnetic field having a magnetic field direction
heading from the S pole to the N pole may be formed in each of the static magnetic
field generators 210, 220, 230, and 240. Here, the static magnetic field generated
in the first static magnetic field generator 210 may have a magnetic field direction
heading from the other side of the first core 212 and one side of the first core 212,
and the static magnetic field generated in the fourth static magnetic field generator
240 may have a magnetic field direction heading from one side of the fourth core 242
and the other side of the fourth core 242. The magnetic field having a direction from
the first static magnetic field generator 210 to the fourth static magnetic field
generator 240, e.g., the first direction, may be formed at one side of the mold 100.
Also, the static magnetic field generated in the third static magnetic field generator
230 may have a magnetic field direction heading from the other side of the third core
232 and one side of the third core 232, and the static magnetic field generated in
the second static magnetic field generator 220 may have a magnetic field direction
heading from one side of the second core 222 and the other side of the second core
222. The magnetic field having a direction from the third static magnetic field generator
230 to the second static magnetic field generator 220, e.g., the second direction,
may be formed at one side of the mold 100. Here, although, herein, the first direction
heads from the first static magnetic field generator 210 to the fourth static magnetic
field generator 240, and the second direction heads from the third static magnetic
field generator 230 to the second static magnetic field generator 220, the first direction
and the second direction may be changed according to a state of supplying the direct
current from the first current supplier 250 to each of the first static magnetic field
generator 210, the second static magnetic field generator 220, the third static magnetic
field generator 230, and the fourth static magnetic field generator 240. However,
even in the case, the first direction and the second direction may be opposite to
each other.
[0059] FIG. 3 is a view for explaining a principle of controlling the flow of the molten
material by using the static magnetic field generator.
[0060] Firstly, the molten material may be injected into the mold 100 by using the nozzle
130. Before the molten material is injected into the mold 100, the nozzle 130 may
be positioned at the central portion in the width direction of the mold 100. Then,
the cast slab may be drawn while forming the static magnetic field applied region
and the non-static magnetic field applied region in the width direction of the mold
100 and controlling the flow of the molten material in the width direction of the
mold 100. Here, the process of forming the static magnetic field applied region and
the non-static magnetic field applied region in the width direction of the mold 100
may be performed before the molten material is injected into the mold 100, after the
molten material is injected into the mold 100, or simultaneously when molten material
is injected into the mold 100.
[0061] The flow of the molten material may be controlled as stated below.
[0062] Referring to FIG 3, when the direct current is supplied to each of the first static
magnetic field generator 210, the second static magnetic field generator 220, the
third static magnetic field generator 230, and the fourth static magnetic field generator
240 through the first current supplier 250, each of the first static magnetic field
generator 210, the second static magnetic field generator 220, the third static magnetic
field generator 230, and the fourth static magnetic field generator 240 may form the
magnetic field. Here, the first static magnetic field generator 210 and the third
static magnetic field generator 230, which are misaligned with respect to the nozzle
130, may have the same polarity, and second static magnetic field generator 220 and
the fourth static magnetic field generator 240, which are misaligned with respect
to the nozzle 130, may also have the same polarity. For example, one side of the first
core 212 and one side of the third core 232 may form the same polarity, e.g., the
N pole, and one side of the second core 222 and one side of the fourth core 242 may
form the same polarity, e.g., the S pole. Also, the static magnetic field formed in
each of the static magnetic field generators 210, 220, 230, and 240 has a magnetic
field direction heading from the S pole to the N pole according to the cores 212,
222, 232, and 242 thereof. Here, the magnetic field formed around each of the cores
212, 222, 232, and 242 may have the magnetic field direction heading from the S pole
to the N pole, and the magnetic field may be formed in the thickness direction of
the mold 100 by the magnetic field direction of the magnetic field formed around each
of the cores 212, 222, 232, and 242. Also, the magnetic field may have a magnetic
field intensity that gradually decreases in a direction away from each of the cores
212, 222, 232, and 242. Thus, the magnetic field may be offset between the first static
magnetic field generator 210 and the fourth static magnetic field generator 240, which
face each other, to form a region in which the magnetic field is not applied or the
magnetic field intensity is extremely weak. This is because the one side of the first
core 212 and the one side of the fourth core 242 have opposite polarities. Also, the
region in which the magnetic field is not applied or the magnetic field intensity
is extremely weak may be also formed between the second static magnetic field generator
220 and the third static magnetic field generator 230, which face each other. This
is because the one side of the second core 222 and the one side of the third core
232 have opposite polarities. Also, the region in which the magnetic field is not
applied or the magnetic field intensity is extremely weak may be also formed between
the first static magnetic field generator 210 and the second static magnetic field
generator 220 and between the third static magnetic field generator 230 and the fourth
static magnetic field generator 240. Thus, the region in which the magnetic field
is not applied or the magnetic field intensity is extremely weak, i.e., the non-static
magnetic field applied region, may be formed between the static magnetic fields generated
from the first static magnetic field generator 210, the second static magnetic field
generator 220, the third static magnetic field generator 230, and the fourth static
magnetic field generator 240, e.g., the central portion in the thickness direction
of the mold 100 and the central portion in the width direction of the mold 100. Here,
a feature in which the magnetic field is not applied or the magnetic field intensity
is extremely weak may represent a case of the magnetic field intensity in a range
from 0 Gauss to 100 Gauss.
[0063] As described above, as the first static magnetic field generator 210, the second
static magnetic field generator 220, the third static magnetic field generator 230,
and the fourth static magnetic field generator 240 are installed on the outside of
the mold 100, the static magnetic field applied region may be formed in the region
in which each of the first static magnetic field generator 210, the second static
magnetic field generator 220, the third static magnetic field generator 230, and the
fourth static magnetic field generator 240 is disposed, and the non-static magnetic
field applied region may be selectively formed between the first static magnetic field
generator 210, the second static magnetic field generator 220, the third static magnetic
field generator 230, and the fourth static magnetic field generator 240. Thus, the
flow velocity of the downflow of the molten material may be reduced by using the magnetic
field in the static magnetic field applied region, and the secondary upflow may be
smoothly formed by minimizing effects of the magnetic field in the non-static magnetic
field applied region. Here, a width of the non-static magnetic field applied region
may be adjusted according to a width of the cast slab to be cast. As described above,
the secondary upflow may be smoothly formed by adjusting the width of the non-static
magnetic field applied region according to the width of the cast slab.
[0064] As the example in which the first core 212 and the second core 222, and the third
core 232 and the fourth core 242 are spaced apart from each other in the width direction
of the mold 100 herein, the example of forming the non-static magnetic field applied
region and the static magnetic field applied region in the width direction of the
mold 100 is described. However, the non-static magnetic field applied region and the
static magnetic field may be formed in the thickness direction of the mold 100.
[0065] FIG. 4 is a cross-sectional view illustrating a casting equipment in accordance with
a modified example. The casting equipment in accordance with a modified example may
have almost the structure as the above-described casting equipment in accordance with
an exemplary embodiment except that a first static magnetic field generator 210 and
a second static magnetic field generator 220 is connected by a first connection core
272, and a third static magnetic field generator 230 and a fourth static magnetic
field generator 240 is connected by a second connection core 274.
[0066] The first connection core 272 may connect a first core 212 of the first static magnetic
field generator 210 and a second core 222 of the second static magnetic field generator
220 in a width direction of a mold 100. Here, the first connection core 272 may connect
the other side of the first core 212 and the other side of the second core 222 and
be spaced apart from an outer surface of a first long side plate 111 of the mold 100.
The second connection core 274 may connect a third core 232 of the third static magnetic
field generator 230 and a fourth core 242 of the fourth static magnetic field generator
240 in the width direction of the mold 100. Here, the second connection core 274 may
connect the other side of the third core 232 and the other side of the fourth core
242 and be spaced apart from an outer surface of a second long side plate 113 of the
mold 100.
[0067] As described above, when the first core 212 and the second core 222 are connected
by the first connection core 272, the third core 232 and the fourth core 242 are connected
by the second connection core 274, and a direct current is supplied to the third static
magnetic field generator 230 and the fourth static magnetic field generator 240, a
static magnetic field may be formed in each of the first static magnetic field generator
210, the second static magnetic field generator 220, the third static magnetic field
generator 230, and the fourth static magnetic field generator 240. In this case, the
static magnetic field may be formed in the width direction of the mold 100 at an outside
of the mold 100, and the static magnetic field may be formed along a thickness direction
of the mold 100. For example, a S pole may be formed at one side of each of the first
core 212 and the third core 232, and a N pole may be formed at one side of each of
the second core 222 and the fourth core 242. In this case, the static magnetic field
formed in each of the static magnetic field generators 210, 220, 230, and 240 has
a magnetic field direction heading from the S pole to the N pole according to each
of the cores 212, 222, 232, and 242 thereof. Here, the magnetic field formed around
each of the cores 212, 222, 232, and 242 may have the magnetic field direction heading
from the S pole to the N pole, and the magnetic field may be formed in the thickness
direction of the mold 100 by the magnetic field direction of the magnetic field formed
around each of the cores 212, 222, 232, and 242. The magnetic field having a magnetic
field direction heading from the fourth static magnetic field generator 240 to the
first static magnetic field generator 210 and the magnetic field having a magnetic
field direction heading from the second static magnetic field generator 220 to the
third static magnetic field generator 230 may be formed in the thickness direction
of the mold 100. Also, the magnetic field may have a magnetic field intensity that
gradually decreases in a direction away from each of the cores 212, 222, 232, and
242. Thus, the magnetic field may be offset between the first static magnetic field
generator 210 and the fourth static magnetic field generator 240, which face each
other, to form a region in which the magnetic field is not applied or the magnetic
field intensity is extremely weak. This is because the one side of the first core
212 and the one side of the fourth core 242 have opposite polarities.
[0068] Also, the region in which the magnetic field is not applied or extremely weak may
be also formed between the second static magnetic field generator 220 and the third
static magnetic field generator 230, which face each other. This is because the one
side of the second core 222 and the one side of the third core 232 have opposite polarities.
Also, the region in which the magnetic field is not applied or the magnetic field
intensity is extremely weak may be also formed between the first static magnetic field
generator 210 and the second static magnetic field generator 220 and between the third
static magnetic field generator 230 and the fourth static magnetic field generator
240. Thus, the region in which the magnetic field is not applied or the magnetic field
intensity is extremely weak, i.e., the non-static magnetic field applied region, may
be formed between the static magnetic fields generated from the first static magnetic
field generator 210, the second static magnetic field generator 220, the third static
magnetic field generator 230, and the fourth static magnetic field generator 240,
e.g., the central portion in the thickness direction of the mold 100 and the central
portion in the width direction of the mold 100.
[0069] In addition, the static magnetic field having the magnetic field direction heading
from the first static magnetic field generator 210 to the second static magnetic field
generator 220 may be formed on the first connection core 272 connecting the first
core 212 and the second core 222, and the static magnetic field having the magnetic
field direction heading from the third static magnetic field generator 220 to the
fourth static magnetic field generator 240 may be formed on the second connection
core 274. Here, the magnetic fields formed on the first connection core 272 and the
second connection core 274 may have opposite magnetic field directions.
[0070] Thus, the magnetic field direction may rotate along the width direction and the thickness
direction of the mold 100. Thus, a region in which the magnetic field is not applied
or the magnetic field intensity is extremely weak in the width direction of the mold
100 may be formed between the static magnetic fields formed at both sides in the width
direction of the mold 100. Also, a region in which the magnetic field is not applied
or the magnetic field intensity is extremely weak in the thickness direction of the
mold 100 may be formed between the static magnetic fields formed at both sides in
the thickness direction of the mold 100. Thus, the region in which the magnetic field
is not applied or the magnetic field intensity is extremely weak, i.e., the non-static
magnetic field applied region, may be formed at a position at which a region contacting
the magnetic field formed in the thickness direction of the mold 100 and a region
contacting the magnetic field formed in the width direction of the mold 100 cross
each other, e.g., a central portion of the mold 100.
[0071] FIG. 5 is a view illustrating a state of controlling a flow of a molten material
by a casting method in accordance with an exemplary embodiment.
[0072] Here, (a) of FIG 5 is a view illustrating a flow state of the molten material in
a mold 100 before a flow of each of a downflow and a secondary upflow is controlled
by using a static magnetic field generation unit 200, (b) of FIG. 5 is a view illustrating
a flow state of the molten material when a static magnetic field is applied along
an entire width direction of the mold 100, and (c) of FIG. 5 is a view illustrating
a flow state of the molten material when a static magnetic field applied region and
a non-static magnetic field applied region are formed along the width direction of
the mold 100 by using the static magnetic field generation unit 200.
[0073] A discharge flow of a molten material M discharged through a discharge hole 134 of
a nozzle 130 may collide both inner surfaces of the mold 100 in the width direction
of the mold 100 and then form an upflow and a downflow. In FIG. 5, a reference symbol
MF may represents a mold flux, and a reference symbol MS may represent a mold slag
obtained as the mold flux is melted.
[0074] Referring to (a) of FIG. 5, it may be known that when a flow of the molten material
is not controlled by using the static magnetic field generation unit 200, a movement
distance, i.e., a penetration depth, of an inclusion is deep because the downflow
has a relatively fast flow velocity . In this case, since the flow of the molten material
is not controlled by using the static magnetic field generation unit 200, the secondary
upflow may be smoothly formed. However, since the inclusion contained in the molten
material moves far along a longitudinal direction of the mold 100, i.e., a drawing
direction of a cast slab, by the downflow, the inclusion may not sufficiently float
by the secondary upflow, and thus a large amount of inclusions are still remained.
[0075] Referring to (b) of FIG 5, it may be known that when the magnetic field is applied
along the entire width direction of the mold 100, a flow velocity of the downflow
is reduced by the magnetic field, and a downward movement distance of the inclusion
becomes short. Also, since the secondary upflow is not properly formed as the formation
of the secondary upflow is restricted by the magnetic field, the including moving
by the downflow in the longitudinal direction of the mold 100, i.e., the drawing direction
of the cast slab, may not float upward and stay in the molten material.
[0076] However, referring to (c) of FIG. 5, it may be known that when the flow of the molten
material is controlled by using the static magnetic field generation unit 200, the
flow velocity of the downflow is reduced at both sides in the width direction of the
mold 100, and the downward movement distance of the inclusion becomes short. Also,
as the non-static magnetic field applied region is formed at the central portion in
the width direction of the mold 100 that is the non-static magnetic field applied
region, the secondary upflow may be sufficiently formed, and the inclusion contained
in the molten material may smoothly float upward and be removed.
[0077] FIG. 6 is a view illustrating a flow analysis result of the secondary upflow in the
mold according to whether the non-static magnetic field applied region is formed in
the width direction of the mold. Here, (a) of FIG. 6 is a view illustrating a flow
state of the molten material when the static magnetic field is applied to the entire
width direction of the mold, and (b) of FIG. 6 is a view illustrating a flow state
of the molten material when the non-static magnetic field applied region is formed
at the central portion in the width direction of the mold.
[0078] Referring to (a) of FIG. 6, it may be known that when the static magnetic field is
applied to the entire width direction of the mold, the secondary upflow is almost
not formed. However, referring to (b) of FIG 6, it may be known that when the non-static
magnetic field applied region is formed at the central portion in the width direction
of the mold, the secondary upflow is smoothly formed at the central portion in the
width direction of the mold, to which the static magnetic field is not applied.
[0079] As described above, as the static magnetic field applied region and the non-static
magnetic field applied region are selectively formed along the width direction of
the mold, the flow of the molten material in the mold may be locally controlled to
secure a clearness of the molten material. Also, the cast slab that is cast by using
the above-described molten material may have an improved quality.
[0080] The casting equipment in accordance with an exemplary embodiment may include a dynamic
magnetic field generation unit 300 disposed above the static magnetic field generation
unit 200 at the outside of the mold 100 in order to control the flow of the molten
material above the static magnetic field generation unit 200. Here, the control unit
400 may control an operation of the dynamic magnetic field generation unit 300 to
adjust at least one of an intensity and a direction of a dynamic magnetic field.
[0081] A portion of the molten material discharged from the nozzle 130 may form an upflow
that collides with the short side plate 120 and then moves upward. Also, the upflow
horizontally moves toward the central portion in the width direction of the mold as
a movement direction of the upflow is changed around a molten surface of the molten
material. A flow of the molten material moving toward the central portion in the width
direction of the mold, e.g., a horizontal directional flow, may collide with a flow
of the molten material moving from an opposite direction thereof to form a vortex
around the nozzle 130. Here, when the horizontal directional flow has an extremely
fast flow velocity, a different kind of material such as the mold flux or the mold
slag disposed on the molten material may be mixed with the molten material. However,
when the horizontal directional flow has an extremely slow flow velocity, the molten
material in the mold 100 may have an ununiform temperature. Thus, as the horizontal
directional flow of the molten material around the molten surface of the molten material
is controlled by using the dynamic magnetic field generation unit 300, the different
kind of material such as the mold flux or the mold slag may be restricted from being
mixed into the molten material, and the temperature of the molten material in the
mold 100 may be uniformly controlled. The flow velocity of the horizontal directional
flow of the molten material may be affected by the flow velocity of the molten material
discharged through the discharge hole 134 of the nozzle 130, i.e., the flow velocity
of the discharge flow. Thus, as the flow velocity of the discharge flow is controlled
by using the dynamic magnetic field generation unit 300, the flow velocity of the
horizontal directional flow of the molten material formed around the molten surface
of the molten material may be controlled.
[0082] FIG. 7 is a cross-sectional view illustrating the casting equipment taken along line
B-B' of FIG 1.
[0083] The dynamic magnetic field generation unit 300 may be disposed above the static magnetic
field generation unit 200, e.g., disposed between the molten surface of the molten
material and the lower end of the nozzle 130, to control the flow of the molten material
in a direction different from the static magnetic field generation unit 200. Referring
to FIG. 7, the dynamic magnetic field generation unit 300 may include a plurality
of dynamic magnetic field generators 310, 320, 330, and 340 spaced apart from each
other in the width direction of the long side plate and a second current supplier
350 selectively supplying an alternating current to the plurality of dynamic magnetic
field generators. The plurality of dynamic magnetic field generators 310, 320, 330,
and 340 may include: a first dynamic magnetic field generator 310 disposed in parallel
to the first static magnetic field generator 210 above the first static magnetic field
generator 210; a second dynamic magnetic field generator 320 spaced apart from the
first dynamic magnetic field generator 310 so that the nozzle 130 is disposed therebetween
and disposed in parallel to the second static magnetic field generator 220 above the
second static magnetic field generator 220; a third dynamic magnetic field generator
330 facing the second dynamic magnetic field generator 310 and disposed in parallel
to the third static magnetic field generator 230 above the third static magnetic field
generator 230; and a fourth dynamic magnetic field generator 340 spaced apart from
the third dynamic magnetic field generator 330 so that the nozzle 130 is disposed
therebetween and disposed in parallel to the fourth static magnetic field generator
240 above the fourth static magnetic field generator 240. That is, the first dynamic
magnetic field generator 310 and the second dynamic magnetic field generator 320 may
be disposed at the outside of the first long side plate 111 to form a dynamic magnetic
field applied region and a non-dynamic magnetic field applied region in the width
direction of the mold 100. Also, the third dynamic magnetic field generator 330 and
the fourth dynamic magnetic field generator 340 may be disposed at the outside of
the second long side plate 113 to form a dynamic magnetic field applied region and
a non-dynamic magnetic field applied region in the width direction of the mold 100.
Each of the first dynamic magnetic field generator 310, the second dynamic magnetic
field generator 320, the third dynamic magnetic field generator 330, and the fourth
dynamic magnetic field generator 340 may include a plurality of cores and a coil wound
around an outside of the core. Each of the dynamic magnetic field generators 310,
320, 330, and 340 may include three, four, five, or more cores. Hereinafter, an example
in which each of the dynamic magnetic field generators 310, 320, 330, and 340 includes
four cores will be described.
[0084] For example, the first dynamic magnetic field generator 310 may include a first core
312a, a second core 312b, a third core 312c, and a fourth core 312d, which are arranged
in parallel in the width direction of the mold 100, and a first coil 314a, a second
coil 314b, a third coil 314c, and a fourth coil 314d, which are respectively wound
around the cores 312a, 312b, 312c, and 312d. Also, the second current supplier 350
may be electrically connected with the first coil 314a, the second coil 314b, the
third coil 314c, and the fourth coil 314d and selectively supply an alternating current
to each of the coils 314a, 314b, 314c, and 314d. In this case, the second current
supplier 350 may apply a cosine type current to each of the coils 314a, 314b, 314c,
and 314d so that each of the coils 314a, 314b, 314c, and 314d has the S pole and the
N pole at a phase difference of 0°, 90°, 180°, and 270° as shown in table 1 below.
[Table 1]
| |
First coil |
Second coil |
Third coil |
Fourth coil |
| 0° |
s |
- |
N |
- |
| 90° |
- |
s |
- |
N |
| 180° |
N |
- |
s |
- |
| 270° |
- |
N |
- |
s |
[0085] Referring to table 1, when an alternating current power having a phase of 0° is supplied
to the first coil 314a and the third coil 314c, the first coil 314a may have the S
pole, and the third coil 314c may have the N pole. Also, when an alternating current
power having a phase of 90° is supplied to the second coil 314b and the fourth coil
314d, the second coil 314b may have the S pole, and the fourth coil 314d may have
the N pole. When an alternating current power having a phase of 180° is supplied to
the first coil 314a and the third coil 314c, the first coil 314a may have the N pole,
and the third coil 314c may have the S pole. Also, when an alternating current power
having a phase of 270° is supplied to the second coil 314b and the fourth coil 314d,
the second coil 314b may have the N pole, and the fourth coil 314d may have the S
pole. When the alternating current power is supplied to each of the coils as described
above, the polarity of each of the coils is periodically changed according to the
phase of the supplied alternating current. Thus, a magnetic field, i.e., a dynamic
magnetic field, moving in a direction in which the coils are arranged, i.e., the width
direction of the mold 100, may be formed in the first dynamic magnetic field generator
310.
[0086] The dynamic magnetic field may be formed in each of the second dynamic magnetic field
generator 320, the third dynamic magnetic field generator 330, and the fourth dynamic
magnetic field generator 340 in the same methods as the first dynamic magnetic field
generator 310. Thus, the dynamic magnetic field applied region and the non-dynamic
magnetic field applied region may be formed along the width direction of the mold
100. In FIG. 7, reference symbols 322a to 322d and 324a to 324d represent the core
and coil of the second dynamic magnetic field generator 320, reference symbols 332a
to 332d and 334a to 334d represent the core and coil of the third dynamic magnetic
field generator 330, and reference symbols 342a to 342d and 344a to 344d represent
the core and coil of the fourth dynamic magnetic field generator 340.
[0087] The second current supplier 350 may supply an alternating current to the first dynamic
magnetic field generator 310, the second dynamic magnetic field generator 320, the
third dynamic magnetic field generator 330, and the fourth dynamic magnetic field
generator 340 so that the magnetic field direction is formed in the width direction
of the mold 100. Here, the second current supplier 350 may control the horizontal
directional flow formed by the upflow by controlling the flow of the discharge flow
in the mold 100. To this end, the second current supplier 350 may supply the alternating
current to the first dynamic magnetic field generator 310, the second dynamic magnetic
field generator 320, the third dynamic magnetic field generator 330, and the fourth
dynamic magnetic field generator 340 so that the magnetic field direction is formed
in the horizontal direction similar to the movement direction of the discharge flow,
i.e., the width direction of the mold 100. In this case, the second current supplier
350 may supply the alternating current so that at least a portion of the dynamic magnetic
field generators 310, 320, 330, and 340 form the dynamic magnetic fields in different
directions. For example, the second current supplier 350 may supply the alternating
current in order to form the dynamic magnetic field on the first dynamic magnetic
field generator 310 and the second dynamic magnetic field generator 320, which are
disposed on the outside of the first long side plate 111, in the same direction, e.g.,
in the third direction, and form the dynamic magnetic field on the third dynamic magnetic
field generator 330 and the fourth dynamic magnetic field generator 340, which are
disposed on the outside of the second long side plate 113, in the same direction,
e.g., in the fourth direction. Here, the third direction and the fourth direction
may be opposite to each other. Alternatively, the second current supplier 350 may
supply the alternating current in order to form the dynamic magnetic field on the
first dynamic magnetic field generator 310 and the fourth dynamic magnetic field generator
340, which face each other, in the same direction, e.g., in the third direction, and
form the dynamic magnetic field on the second dynamic magnetic field generator 320
and the third dynamic magnetic field generator 330, which face each other, in the
same direction, e.g., in the fourth direction. Here, the magnetic field direction
formed by each of the first dynamic magnetic field generator 310, the second dynamic
magnetic field generator 320, the third dynamic magnetic field generator 330, and
the fourth dynamic magnetic field generator 340 may be changed according to the flow
velocity of the discharge flow discharged from the discharge hole 134 of the nozzle
130.
[0088] FIG. 8 is a view illustrating an example of controlling the flow of the molten material
by using the dynamic magnetic field generator. As illustrated in (a) of FIG. 8, when
the discharge flow has an extremely fast flow velocity, a flow velocity of a horizontal
directional flow around the molten surface of the molten material becomes fast. In
this case, the second current supplier 350 may supply the alternating current to the
first dynamic magnetic field generator 310, the second dynamic magnetic field generator
320, the third dynamic magnetic field generator 330, and the fourth dynamic magnetic
field generator 340 so that the dynamic magnetic field is formed in a direction opposite
to the movement direction of the discharge flow. Here, the second current supplier
350 may supply the alternating current to the first dynamic magnetic field generator
310, the second dynamic magnetic field generator 320, the third dynamic magnetic field
generator 330, and the fourth dynamic magnetic field generator 340 so that the dynamic
magnetic field direction is formed from the edge to the central portion of the mold
100. Thus, as the flow velocity of the discharge flow formed by being discharged from
the discharge hole 134 of the nozzle 130 is reduced, the molten surface of the molten
material may be stably controlled.
[0089] On the other hand, as illustrated in (b) of FIG. 8, when the discharge flow has an
extremely slow flow velocity, the flow velocity of the horizontal directional flow
around the molten surface of the molten material becomes slow. In this case, the second
current supplier 350 may supply the alternating current to the first dynamic magnetic
field generator 310, the second dynamic magnetic field generator 320, the third dynamic
magnetic field generator 330, and the fourth dynamic magnetic field generator 340
so that the dynamic magnetic field is formed in the same direction as the movement
direction of the discharge flow. Here, the second current supplier 350 may supply
the alternating current to the first dynamic magnetic field generator 310, the second
dynamic magnetic field generator 320, the third dynamic magnetic field generator 330,
and the fourth dynamic magnetic field generator 340 so that the dynamic magnetic field
direction is formed from the central portion to the edge of the mold 100. Accordingly,
the flow velocity of the discharge flow formed by being discharged from the discharge
hole 134 of the nozzle 130 may be accelerated to smoothly form the flow such as the
downflow, the upflow, and the secondary upflow. Thus, the temperature of the molten
material in the mold 100 may be uniformly controlled.
[0090] Also, the second current supplier 350 may supply the alternating current to the first
dynamic magnetic field generator 310, the second dynamic magnetic field generator
320, the third dynamic magnetic field generator 330, and the fourth dynamic magnetic
field generator 340 in order to form the dynamic magnetic field rotating in a circumferential
direction of the mold 100. In case of forming the dynamic magnetic field in the circumferential
direction of the mold 100, when the temperature of the molten material around the
molten surface of the molten material is ununiform or decreases, the temperature of
the molten material around the molten surface may be uniformly controlled by stirring
the molten material. Although the method of controlling the horizontal directional
flow and the discharge flow of the molten material by controlling the magnetic field
direction, i.e., the dynamic magnetic field direction, is described herein, the flow
of the molten material may be controlled by changing at least one of the magnetic
field direction and the magnetic field intensity as necessary. Here, the magnetic
field intensity may be changed by adjusting the current amount of the alternating
current supplied to each of the dynamic magnetic field generators 310, 320, 330, and
340.
[0091] As the horizontal directional flow and the discharge flow of the molten material
in the mold is controlled by using the dynamic magnetic field generation unit 300
based on the above-described method, the molten surface of the molten material may
be stabilized, and the different kind of material such as the mold slag or the mold
flux disposed on the molten surface of the molten material may be restricted or prevented
from being mixed into the molten material.
[0092] Although the exemplary embodiments of the present invention have been described,
it is understood that the present invention should not be limited to these exemplary
embodiments but various changes and modifications can be made by one ordinary skilled
in the art within the spirit and scope of the present invention as hereinafter claimed.
Hence, the real protective scope of the present invention shall be determined by the
technical scope of the accompanying claims.
INDUSTRIAL APPLICABILITY
[0093] In accordance with an exemplary embodiment, as the flow of the molten material is
selectively controlled in the longitudinal direction of the mold by selectively applying
the static magnetic field in the width direction of the mold, the different kind of
material such as the mold flux or the mold slag may be restricted from being mixed
with the molten material to manufacture a high quality product. Through this, as the
cleanliness of the molten material is secured, a product manufactured by using the
molten material may have an improved quality.
1. A casting equipment for casting a cast slab, comprising:
a mold configured to provide an inner space for accommodating a molten material;
a nozzle disposed above the mold to supply the molten material into the mold;
a static magnetic field generation unit disposed on an outside in a width direction
of the mold so that magnetic fields at both edges in the width direction of the mold
are controlled in different directions; and
a control unit configured to control an operation of the static magnetic field generation
unit.
2. The casting equipment of claim 1, wherein the mold comprises one pair of long side
plates spaced apart from each other and one pair of short side plates configured to
connect both sides of each of the one pair of long side plates, and
the static magnetic field generation unit comprises:
a plurality of static magnetic field generators disposed in a width direction of the
long side plate below the nozzle so as to be spaced apart from a central portion in
the width direction of the mold; and
a first current supplier configured to supply a direct current to the plurality of
static magnetic field generators so as to form a magnetic field passing in a thickness
direction of the mold at both sides of the nozzle in the width direction of the mold.
3. The casting equipment of claim 2, wherein each of the plurality of static magnetic
field generators comprises:
a core extending along a portion of the width direction of the long side plate and
spaced apart from another core; and
a coil wound around an outside of the core.
4. The casting equipment of claim 3, wherein the plurality of static magnetic field generators
comprise:
a first static magnetic field generator;
a second static magnetic field generator disposed at one side of the first static
magnetic field generator while being spaced apart therefrom so that the nozzle is
disposed therebetween;
a third static magnetic field generator disposed to face the second static magnetic
field generator; and
a fourth static magnetic field generator disposed at one side of the third static
magnetic field generator while being spaced apart therefrom so that the nozzle is
disposed therebetween and disposed to face the first static magnetic field generator,
and
the first current supplier supplies a direct current to the first static magnetic
field generator, the second static magnetic field generator, the third static magnetic
field generator, and the fourth static magnetic field generator so as to form opposite
polarities in directions facing each other in the thickness direction of the mold
and opposite polarities in the width direction of the mold.
5. The casting equipment of claim 4, wherein the first static magnetic field generator
and the second static magnetic field generator are spaced by a first distance from
each other, and the third static magnetic field generator and the fourth static magnetic
field generator are spaced by a second distance from each other,
wherein the first distance is the same as the second distance.
6. The casting equipment of claim 5, wherein when the cast slab has an entire width of
100, each of the first distance and the second distance is in a range from 4 to 36.
7. The casting equipment of claim 6, wherein at least one of the first static magnetic
field generator, the second static magnetic field generator, the third static magnetic
field generator, and the fourth static magnetic field generator is movable along the
width direction of the mold.
8. The casting equipment of claim 7, further comprising:
a first connection core configured to connect the first static magnetic field generator
and the second static magnetic field generator; and
a second connection core configured to connect the third static magnetic field generator
and the fourth static magnetic field generator.
9. The casting equipment of claim 8, wherein the static magnetic field generation unit
forms a magnetic field that rotates in a circumferential direction of the mold.
10. The casting equipment of any one of claims 1 to 9, further comprising a dynamic magnetic
field generation unit disposed above the static magnetic field generation unit to
form a dynamic magnetic field for controlling a flow of the molten material,
wherein the control unit controls an operation of the dynamic magnetic field generation
unit so as to adjust at least one of an intensity and a direction of the dynamic magnetic
field.
11. The casting equipment of claim 10, wherein the dynamic magnetic field generation unit
comprises a plurality of dynamic magnetic field generators configured to form a dynamic
magnetic field at both sides of the nozzle in the width direction of the mold.
12. The casting equipment of claim 11, wherein the dynamic magnetic field generation unit
is disposed in parallel to the static magnetic field generation unit and controls
the flow of the molten material in a direction different from the static magnetic
field generation unit.
13. A casting method comprising:
injecting a molten material into a mold by using a nozzle;
forming a static magnetic field applied region and a non-static magnetic field applied
region in a width direction of the mold and controlling a flow of the molten material
in a longitudinal direction of the mold; and
drawing a cast slab.
14. The casting method of claim 13, further comprising, before the injecting of the molten
material, arranging the nozzle at a central portion in the width direction of the
mold,
wherein the controlling of the flow of the molten material comprises forming the non-static
magnetic field applied region at a central portion in the width direction of the mold
and forming the static magnetic field applied region at both sides of the non-static
magnetic field applied region.
15. The casting method of claim 14, wherein the controlling of the flow of the molten
material comprises forming the static magnetic field applied region and the non-static
magnetic field applied region below the nozzle.
16. The casting method of claim 15, wherein the controlling of the flow of the molten
material comprises forming a magnetic field along a thickness direction of the mold,
and
the forming of the static magnetic field applied region comprises forming a static
magnetic field so that magnetic fields at both sides of the nozzle have opposite directions.
17. The casting method of claim 16, wherein the controlling of the flow of the molten
material comprises forming the non-static magnetic field applied region at a portion
of the central portion in the width direction of the mold, at which the nozzle is
disposed.
18. The casting method of claim 17, wherein the controlling of the flow of the molten
material comprises controlling a range of the static magnetic field applied region
so that the non-static magnetic field applied region has a magnetic field of 0 Gauss
to 100 Gauss.
19. The casting method of claim 18, wherein the controlling of the flow of the molten
material comprises adjusting a distance between the static magnetic field applied
regions according to a width of the cast slab.
20. The casting method of claim 19, wherein the controlling of the flow of the molten
material comprises forming the static magnetic field applied region at both edges
in the width direction of the mold to reduce a flow velocity of a downflow of the
molten material and forming the non-static magnetic field applied region between the
static magnetic field applied regions to form an upflow of the molten material.
21. The casting method of claim 20, wherein the controlling of the flow of the molten
material further comprises forming a dynamic magnetic field applied region and a non-dynamic
magnetic field applied region to control the flow of the molten material in the width
direction of the mold.
22. The casting method of claim 21, wherein the controlling of the flow of the molten
material in the width direction of the mold comprises forming a dynamic magnetic field
applied region and a non-dynamic magnetic field applied region between a molten surface
of the molten material and a lower end of the nozzle.
23. The casting method of claim 22, wherein the forming of the dynamic magnetic field
applied region comprises forming a dynamic magnetic field in the width direction of
the mold at both sides of the nozzle in the width direction of the mold.
24. The casting method of claim 23, wherein the forming of the dynamic magnetic field
applied region comprises adjusting at least one of an intensity and a direction of
the dynamic magnetic field.