Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02908090 2015-09-25
DESCRIPTION
PULLING-UP-TYPE CONTINUOUS CASTING APPARATUS AND PULLING-UP-
TYPE CONTINUOUS CASTING METHOD
Technical Field
[0001]
The present invention relates to a pulling-up-type continuous casting
apparatus and a
pulling-up-type continuous casting method.
Background Art
[0002]
As a revolutionary continuous casting method that does not requires any mold,
Patent
Literature 1 proposes a pulling-up-type free casting method. As shown in
Patent Literature 1,
after a starter is submerged under the surface of a melted metal (molten
metal) (i.e., molten-
metal surface), the starter is pulled up, so that some of the molten metal
follows the starter and is
drawn up by the starter by the surface film of the molten metal and/or the
surface tension. Note
that it is possible to continuously cast a cast-metal article having a desired
cross-sectional shape
by drawing the molten metal and cooling the drawn molten metal through a shape
defining
member disposed in the vicinity of the molten-metal surface.
[0003]
In the ordinary continuous casting method, the shape of the cast-metal article
in the
longitudinal direction as well as the shape thereof in cross section is
defined by the mold. In the
continuous casting method, in particular, since the solidified metal (i.e.,
cast-metal article) needs
to pass through the inside of the mold, the cast-metal article has such a
shape that it extends in a
straight-line shape in the longitudinal direction.
In contrast to this, the shape defining member used in the free casting method
defines
only the cross-sectional shape of the cast-metal article, while it does not
define the shape in the
longitudinal direction. Further, since the shape defining member can be moved
in the direction
parallel to the molten-metal surface (i.e., in the horizontal direction), cast-
metal articles having
various shapes in the longitudinal direction can be produced. For example,
Patent Literature 1
discloses a hollow cast-metal article (i.e., a pipe) having a zigzag shape or
a helical shape in the
longitudinal direction rather than the straight-line shape.
Citation List
Patent Literature
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2
[0004]
Patent Literature 1: Japanese Unexamined Patent Application Publication No.
2012-61518
Summary of Invention
Technical Problem
[0005]
The present inventors have found the following problem.
In the free casting method disclosed in Patent Literature 1, the molten metal
drawn up
through the shape defining member is cooled by a cooling gas. Specifically, a
cooling gas is
blown on the cast metal immediately after it is solidified and the molten
metal is thereby
indirectly cooled. It should be noted that by increasing the flow rate of the
cooling gas, the
casting speed can be increased and the productively can be thereby improved.
However, there
has been a problem that when the flow rate of the cooling gas is increased, an
undulation occurs
in the molten metal drawn up from the shape defining member due to the cooling
gas and hence
the size accuracy and the surface quality of the cast-metal article
deteriorate.
[0006]
The present invention has been made in view of the above-described problem,
and an
object thereof is to provide a pulling-up-type continuous casting apparatus
capable of producing
cast-metal articles having excellent size accuracy and surface quality, and
having excellent
productivity.
Solution to Problem
[0007]
A pulling-up-type continuous casting apparatus according to an aspect of the
present
invention includes:
a holding furnace that holds molten metal;
a shape defining member disposed near a molten-metal surface of the molten
metal held
in the holding furnace, the shape defining member being configured to define a
cross-sectional
shape of a cast-metal article to be cast as the molten metal passes through
the shape defining
member;
a first nozzle that blows a cooling gas on the cast-metal article, the cast-
metal article
being formed as the molten metal that has passed through the shape defining
member solidifies;
and
a second nozzle that blows a gas toward the cast-metal article in an obliquely
upward
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direction from below a place on the cast-metal article on which the cooling
gas is blown from the
first nozzle.
The above-described configuration makes it possible to provide a pulling-up-
type
continuous casting apparatus capable of producing cast-metal articles having
excellent size
accuracy and surface quality, and having excellent productivity.
[0008]
The second nozzle is preferably fixed on the shape defining member or formed
inside
the shape defining member. This configuration can reduce the necessary space.
Further, the pulling-up-type continuous casting apparatus preferably further
includes a
projection disposed on the shape defining member, the projection being
disposed at an end on a
side of the shape defining member where the molten metal passes through, the
projection
extending in a pulling-up direction. Further, a tip of the second nozzle is
preferably formed on a
top surface of the projection.
[0009]
An angle between a surface of the cast-metal article and a flux of the gas
blown from
the second nozzle is preferably equal to or less than 25 degrees. This
configuration can
effectively block the cooling gas.
Further, the gas blown from the second nozzle is preferably the same gas as
the cooling
gas blown from the first nozzle. This can simplify the equipment.
[0010]
A pulling-up-type continuous casting apparatus according to another aspect of
the
present invention includes:
a holding furnace that holds molten metal;
a shape defining member disposed near a molten-metal surface of the molten
metal held
in the holding furnace, the shape defining member being configured to define a
cross-sectional
shape of a cast-metal article to be cast as the molten metal passes through
the shape defining
member;
a nozzle that blows a cooling gas on the cast-metal article, the cast-metal
article being
formed as the molten metal that has passed through the shape defining member
solidifies; and
a projection disposed on the shape defining member, the projection being
disposed at an
end on a side of the shape defining member where the molten metal passes
through, the
projection extending in a pulling-up direction.
The above-described configuration makes it possible to provide a pulling-up-
type
continuous casting apparatus capable of producing cast-metal articles having
excellent size
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accuracy and surface quality, and having excellent productivity.
[0011]
A pulling-up-type continuous casting method according to an aspect of the
present
invention includes:
a step of pulling up molten metal held in a holding furnace while making the
molten
metal pass through a shape defining member, the shape defining member being
configured to
define a cross-sectional shape of a cast-metal article to be cast; and
a step of blowing a cooling gas on the cast-metal article, the cast-metal
article being
formed from the molten metal that has passed through the shape defining
member, in which
in the step of blowing the cooling gas, a gas is blown toward the cast-metal
article in an
obliquely upward direction from below a place on the cast-metal article on
which the cooling gas
is blown.
The above-described configuration makes it possible to provide a pulling-up-
type
continuous casting method capable of producing cast-metal articles having
excellent size
accuracy and surface quality, and having excellent productivity. The pulling-
up-type continuous
casting method preferably further includes a step of adjusting a flow rate of
the gas according to
a flow rate of the cooling gas.
[0012]
The nozzle for blowing the gas toward the cast-metal article in the obliquely
upward
direction is preferably fixed on the shape defining member or formed inside
the shape defining
member. This configuration can reduce the necessary space.
Further, a projection is preferably provided on the shape defining member, the
projection being disposed at an end on a side of the shape defining member
where the molten
metal passes through, the projection extending in a pulling-up direction.
Further, a tip of the
nozzle is preferably formed on a top surface of the projection.
[0013]
An angle between a surface of the cast-metal article and a flux of the gas
blown toward
the cast-metal article in the obliquely upward direction is preferably equal
to or less than 25
degrees. This configuration can effectively block the cooling gas.
Further, the gas blown toward the cast-metal article in the obliquely upward
direction is
preferably the same gas as the cooling gas. This can simplify the equipment.
[0014]
A pulling-up-type continuous casting method according to another aspect of the
present
invention includes:
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a step of pulling up molten metal held in a holding furnace while making the
molten
metal pass through a shape defining member, the shape defining member being
configured to
define a cross-sectional shape of a cast-metal article to be cast; and
a step of blowing a cooling gas on the cast-metal article, the cast-metal
article being
5 formed from the molten metal that has passed through the shape defining
member, in which
a projection is provided on the shape defining member, the projection being
disposed at
an end on a side of the shape defining member where the molten metal passes
through, the
projection extending in a pulling-up direction.
The above-described configuration makes it possible to provide a pulling-up-
type
continuous casting method capable of producing cast-metal articles having
excellent size
accuracy and surface quality, and having excellent productivity.
Advantageous Effects of Invention
[0015]
According to the present invention, it is possible to provide a pulling-up-
type
continuous casting apparatus capable of producing cast-metal articles having
excellent size
accuracy and surface quality, and having excellent productivity.
Brief Description of Drawings
[0016]
Fig. 1 is a schematic cross section of a free casting apparatus according to a
first
exemplary embodiment;
Fig. 2 is a plan view of a shape defining member 102 according to the first
exemplary
embodiment;
Fig. 3 is a side view showing a positional relation between a gas blowing-up
nozzle 104
and a cooling gas nozzle 106 provided in the free casting apparatus according
to a first
exemplary embodiment;
Fig. 4 is a diagram for explaining an effect of an angle 0 between the flux of
a blocking
gas and the surface of cast metal M3;
Fig. 5 is a graph for explaining an effect of an angle 0 between the flux of a
blocking
gas and the surface of cast metal M3;
Fig. 6 is a plan view of a shape defining member 102 according to a modified
example
of the first exemplary embodiment;
Fig. 7 is a side view of the shape defining member 102 according to the
modified
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example of the first exemplary embodiment;
Fig. 8 is a schematic cross section of a free casting apparatus according to a
second
exemplary embodiment;
Fig. 9 is a schematic cross section of a free casting apparatus according to a
third
exemplary embodiment;
Fig. 10 is a schematic cross section of a free casting apparatus according to
a modified
example of the third exemplary embodiment; and
Fig. 11 is a schematic cross section of a free casting apparatus according to
a fourth
exemplary embodiment.
Description of Embodiments
[0017]
Specific exemplary embodiments to which the present invention is applied are
explained
hereinafter in detail with reference to the drawings. However, the present
invention is not
limited to exemplary embodiments shown below. Further, the following
descriptions and the
drawings are simplified as appropriate for clarifying the explanation.
[0018]
[First exemplary embodiment]
Firstly, a free casting apparatus (pulling-up-type continuous casting
apparatus)
according to a first exemplary embodiment is explained with reference to Fig.
1. Fig. 1 is a
schematic cross section of a free casting apparatus according to the first
exemplary embodiment.
As shown in Fig. 1, the free casting apparatus according to the first
exemplary embodiment
includes a molten-metal holding furnace 101, a shape defining member 102, a
gas blowing-up
nozzle(s) 104, an actuator(s) 105, a cooling gas nozzle(s) 106, and a pulling-
up machine 108. In
Fig. 1, the xy-plane forms a horizontal plane and the z-axis direction is the
vertical direction.
More specifically, the positive direction on the z-axis is the vertically
upward direction.
[0019]
The molten-metal holding furnace 101 contains molten metal M1 such as aluminum
or
its alloy, and maintains the molten metal M1 at a predetermined temperature.
In the example
shown in Fig. 1, since the molten-metal holding furnace 101 is not replenished
with molten metal
during the casting process, the surface of molten metal M1 (i.e., molten-metal
surface) is
lowered as the casting process advances. Alternatively, the molten-metal
holding furnace 101
may be replenished with molten metal as required during the casting process so
that the molten-
metal surface is kept at a fixed level. Note that the position of the
solidification interface can be
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raised by increasing the setting temperature of the holding furnace and the
position of the
solidification interface can be lowered by lowering the setting temperature of
the holding furnace.
Needless to say, the molten metal M1 may be a metal or an alloy other than
aluminum.
[0020]
The shape defining member 102 is made of ceramic or stainless steel, for
example, and
disposed near the molten-metal surface. In the example shown in Fig. 1, the
shape defining
member 102 is disposed so that a gap G between its principal surface on the
underside (molten
metal side) and the molten-metal surface is about 0.5 mm. By providing the gap
G, it is possible
to prevent the shape defining member 102 from lowering the temperature of the
molten metal.
[0021]
Meanwhile, the shape defining member 102 is in contact with held molten metal
M2,
which is pulled up from the molten-metal surface, on the periphery of its
opening (molten-metal
passage section 103) through which molten metal passes. Therefore, the shape
defining member
102 can define the cross-sectional shape of cast metal M3 to be cast while
preventing oxide films
formed on the surface of the molten metal M1 and foreign substances floating
on the surface of
the molten metal M1 from entering the cast metal M3. The cast metal M3 shown
in Fig. 1 is a
solid cast-metal article having a plate-like shape in a horizontal cross
section (hereinafter
referred to as "lateral cross section").
[0022]
Alternatively, the shape defining member 102 may be disposed so that its
underside
principal surface is entirely in contact with the molten-metal surface. In
that case, the underside
principal surface may be coated with a mold wash having a heat-insulating
property so that the
decrease in the temperature of the molten metal due to the shape defining
member 102 is reduced.
Examples of the mold wash include a vermiculite mold wash. The vermiculite
mold wash is a
mold wash that is obtained by suspending refractory fine particles made of
silicon oxide (Si02),
iron oxide (Fe203), aluminum oxide (A1203), or the like in water.
[0023]
Fig. 2 is a plane view of the shape defining member 102 according to the first
exemplary embodiment. Note that the cross section of the shape defining member
102 shown in
Fig. 1 corresponds to a cross section taken along the line I-I in Fig. 2. As
shown in Fig. 2, the
shape defining member 102 has, for example, a rectangular shape as viewed from
the top, and
has a rectangular opening (molten-metal passage section 103) having a
thickness tl and a width
wl at the center thereof. The molten metal passes through the rectangular
opening (molten-
metal passage section 103). Further, the xyz-coordinate system shown in Fig. 2
corresponds to
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that shown in Fig. 1.
[0024]
As shown in Fig. 1, the molten metal M1 follows the cast metal M3 and is
pulled up by
the cast metal M3 by its surface film and/or the surface tension. Further, the
molten metal M1
passes through the molten-metal passage section 103 of the shape defining
member 102. That is,
as the molten metal M1 passes through the molten-metal passage section 103 of
the shape
defining member 102, an external force(s) is applied from the shape defining
member 102 to the
molten metal M1 and the cross-sectional shape of the cast metal M3 is thereby
defined. Note
that the molten metal that follows the cast metal M3 and is pulled up from the
molten-metal
surface by the surface film of the molten metal and/or the surface tension is
called "held molten
metal M2". Further, the boundary between the cast metal M3 and the held molten
metal M2 is
the solidification interface SIF.
[0025]
As shown in Fig. 1, the gas blowing-up nozzle(s) (second nozzle(s)) 104 is
disposed and
fixed on the shape defining member 102. It should be noted that the gas
blowing-up nozzle 104
blows a gas (hereinafter called "blocking gas") toward the cast metal M3 in an
obliquely upward
direction in order to prevent a cooling gas blown from the cooling gas nozzle
106 onto the cast
metal M3 from causing an undulation on the surface of the held molten metal
M2. Further, the
gas blowing-up nozzle 104 supports the shape defining member 102. Details of
the gas blowing-
up nozzle 104 are described later. Note that a gas similar to the cooling gas
can be used as the
blocking gas. Further, when the blocking gas is the same gas as the cooling
gas, the blocking gas
can also be supplied from the cooling gas supply unit (not shown). That is,
the equipment can be
simplified and hence the use of the same gas is preferred. Note that the gas
blowing-up nozzle
104 does not necessarily have to be fixed on the shape defining member 102.
[0026]
The gas blowing-up nozzle 104 is connected to the actuator 105. The gas
blowing-up
nozzle 104 and the shape defining member 102 can be moved in the up/down
direction (vertical
direction) and the horizontal direction by the actuator 105. This
configuration makes it possible,
for example, to move the shape defining member 102 downward as the molten-
metal surface is
lowered due to the advance of the casting process. Further, since the shape
defining member 102
can be moved in the horizontal direction, the shape in the longitudinal
direction of the cast metal
M3 can be arbitrarily changed.
[0027]
The cooling gas nozzle 106 is cooling means for blowing a cooling gas (such as
air,
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nitrogen, and argon) supplied from the cooling gas supply unit (not shown) on
the cast metal M3
and thereby cooling the cast metal M3. The position of the solidification
interface can be
lowered by increasing the flow rate of the cooling gas and the position of the
solidification
interface can be raised by reducing the flow rate of the cooling gas. Note
that although it is not
shown in the figure, the cooling gas nozzle (cooling unit) 106 can also be
moved in the
horizontal direction and the vertical direction in accordance with the
movement of the gas
blowing-up nozzle 104 and the shape defining member 102.
[0028]
By cooling the cast metal M3 by the cooling gas while pulling up the cast
metal M3 by
using the pulling-up machine 108 connected to the starter ST, the held molten
metal M2 located
in the vicinity of the solidification interface SIF is successively
solidified, and the cast metal M3
is thereby formed. The position of the solidification interface can be raised
by increasing the
pulling-up speed of the pulling-up machine 108 and the position of the
solidification interface
can be lowered by reducing the pulling-up speed.
[0029]
Next, a positional relation between the gas blowing-up nozzle 104 and the
cooling gas
nozzle 106 provided in the free casting apparatus according to the first
exemplary embodiment is
explained with reference to Fig. 3. Fig. 3 is a side view showing a positional
relation between
the gas blowing-up nozzle 104 and the cooling gas nozzle 106 provided in the
free casting
apparatus according to the first exemplary embodiment.
[0030]
As shown in Fig. 3, the flux of the cooling gas for cooling the cast metal M3
is blown
from the cooling gas nozzle 106 in a direction roughly perpendicularly to the
surface of the cast
metal M3. This is because the closer the blowing direction is to the direction
perpendicular to
the surface, the more the cooling efficiency improves. Further, the closer the
tip of the cooling
gas nozzle 106 is to the cast metal M3, the more the casting speed can be
increased. The larger
the flow rate of the cooling gas, the more the casting speed can be increased.
Further, the closer
the place on which the cooling gas is blown is to the solidification
interface, the more the casting
speed can be increased. The cooling gas that has collided onto the surface of
the cast metal M3
branches off into an upward direction and a downward direction along the
surface of the cast
metal M3. Then, if there is nothing that blocks the downward-branched cooling
gas, the
downward-branched cooling gas causes an undulation on the surface of the held
molten metal
M2. When the flow rate of the cooling gas is increased, this undulation
becomes larger, thus
deteriorating the size accuracy and the surface quality of the cast-metal
article.
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[0031]
Therefore, in the free casting apparatus according to the first exemplary
embodiment,
the gas blowing-up nozzle 104 blows a blocking gas in an obliquely upward
direction from a
place located on the shape defining member 102 as shown in Fig. 3. Note that
as is obvious from
5 Fig.3, it is necessary that the place on the surface of the cast metal M3
on which the blocking gas
is blown is located between the place on the surface of the cast metal M3 on
which the cooling
gas is blown and the solidification interface SIF. By using the blocking gas,
it is possible to
block the cooling gas that has branched in the downward direction along the
surface of the cast
metal M3. As a result, it is possible to prevent (or reduce) the occurrence of
an undulation on the
10 surface of the held molten metal M2 and improve the size accuracy and
the surface quality of the
cast-metal article. Further, it is possible to increase the casting speed and
improve the
productivity compared to the related art by increasing the flow rate of the
cooling gas. Further,
the blocking gas can improve the cooling effect of the cast metal M3. Note
that the flow rate of
the blocking gas is preferably adjusted according to the flow rate of the
cooling gas.
[0032]
Next, the effect of the angle 0 between the flux of the blocking gas and the
surface of
the cast metal M3 is explained with reference to Figs. 4 and 5. Fig. 4 is a
schematic diagram for
explaining the effect of the angle 0 between the flux of the blocking gas and
the surface of the
cast metal M3. Letting "QO", "Ql" and "Q2" stand for the total flow rate of
the blocking gas
blown from the gas blowing-up nozzle 104, the flow rate of the blocking gas
that has branched
downward, and the flow rate of the blocking gas that has branched upward,
respectively, as
shown in Fig. 4, a relation "QO = Q1+Q2" holds. Note that the blocking gas is
blown so that the
angle of the blocking gas with respect to the surface of the cast metal M3 is
the angle O.
[0033]
Fig. 5 is a graph for explaining the effect of the angle 0 between the flux of
the blocking
gas and the surface of the cast metal M3. As shown in Fig. 5, as the angle 0
between the flux of
the blocking gas and the surface of the cast metal M3 changes, the ratio (%)
of the flow rate Q1
of the downward-branched blocking gas to the total flow rate QO changes. This
ratio (%) can be
calculated by an expression "1/2x(1-cos0)x100". Fig. 5 shows a plot in
accordance with this
expression. The horizontal axis in Fig. 5 indicates angles O (degrees) and the
vertical axis
indicates ratios Ql\QO (%) of the flow rate Q1 of the downward-branched
blocking gas to the
total flow rate QO. When the ratio Q1 \Q0 (%) increases, the blocking gas
itself causes an
undulation on the surface of the held molten metal M2. The ratio Q
(%) is preferably equal
to or less than 5% and hence the angle 0 is preferably equal to or less than
25 degrees.
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[0034]
Next, a free casting method according to the first exemplary embodiment is
explained
with reference to Fig. 1.
Firstly, a starter ST is lowered and made to pass through the molten-metal
passage
section 103 of the shape defining member 102, and the tip of the starter ST is
submerged into the
molten metal M1.
[0035]
Next, the starter ST starts to be pulled up at a predetermined speed. Note
that even
when the starter ST is pulled away from the molten-metal surface, the molten
metal M1 follows
the starter ST and is pulled up from the molten-metal surface by the surface
film and/or the
surface tension. That is, the held molten metal M2 is formed. As shown in Fig.
1, the held
molten metal M2 is formed in the molten-metal passage section 103 of the shape
defining
member 102. That is, the held molten metal M2 is shaped into a given shape by
the shape
defining member 102.
[0036]
Next, since the starter ST is cooled by the cooling gas blown from the cooling
gas
nozzle 106, the held molten metal M2 successively solidifies from its upper
side toward its lower
side. As a result, the cast metal M3 grows. In this manner, it is possible to
continuously cast the
cast metal M3.
[0037]
As described above, the free casting apparatus according to the first
exemplary
embodiment is equipped with the gas blowing-up nozzle 104 that blows a
blocking gas in an
obliquely upward direction from a place located on the shape defining member
102. By using
this blocking gas, it is possible to block the cooling gas that has branched
in the downward
direction along the surface of the cast metal M3. As a result, it is possible
to prevent (or reduce)
the occurrence of an undulation on the surface of the held molten metal M2 and
improve the size
accuracy and the surface quality of the cast-metal article.
[0038]
(Modified example of first exemplary embodiment)
Next, a free casting apparatus according to a modified example of the first
exemplary
embodiment is explained with reference to Figs. 6 and 7. Fig. 6 is a plan view
of a shape
defining member 102 according to the modified example of the first exemplary
embodiment.
Fig. 7 is a side view of the shape defining member 102 according to the
modified example of the
first exemplary embodiment. Note that the xyz-coordinate systems shown in
Figs. 6 and 7
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correspond to that shown in Fig. 1.
[0039]
The shape defining member 102 according to the first exemplary embodiment
shown in
Fig. 2 is composed of one plate. Therefore, the thickness tl and the width wl
of the molten-
metal passage section 103 are fixed. In contrast to this, the shape defining
member 102
according to the modified example of the first exemplary embodiment includes
four rectangular
shape defining plates 102a, 102b, 102c and 102d as shown in Fig. 6. That is,
the shape defining
member 102 according to the modified example of the first exemplary embodiment
is divided
into a plurality of sections. With this configuration, it is possible to
change the thickness t 1 and
the width w 1 of the molten-metal passage section 103. Further, the four
rectangular shape
defining plates 102a, 102b, 102c and 102d can be moved in unison in the z-axis
direction.
[0040]
As shown in Fig. 6, the shape defining plates 102a and 102b are arranged to be
opposed
to each other in the x-axis direction. Further, as shown in Fig. 7, the shape
defining plates 102a
and 102b are disposed at the same height in the z-axis direction. The gap
between the shape
defining plates 102a and 102b defines the width w 1 of the molten-metal
passage section 103.
Further, since each of the shape defining plates 102a and 102b can be
independently moved in
the x-axis direction, the width w 1 can be changed. Note that, as shown in
Figs. 6 and 7, a laser
displacement gauge S1 and a laser reflector plate S2 may be provided on the
shape defining
plates 102a and 102b, respectively, in order to measure the width w 1 of the
molten-metal
passage section 103.
[0041]
Further, as shown in Fig. 6, the shape defining plates 102c and 102d are
arranged to be
opposed to each other in the y-axis direction. Further, the shape defining
plates 102c and 102c
are disposed at the same height in the z-axis direction. The gap between the
shape defining
plates 102c and 102d defines the thickness t 1 of the molten-metal passage
section 103. Further,
since each of the shape defining plates 102c and 102d can be independently
moved in the y-axis
direction, the thickness t 1 can be changed. The shape defining plates 102a
and 102b are
disposed in such a manner that they are in contact with the top sides of the
shape defining plates
102c and 102d.
[0042]
Next, a driving mechanism for the shape defining plate 102a is explained with
reference
to Figs. 6 and 7. As shown in Figs. 6 and 7, the driving mechanism for the
shape defining plate
102a includes slide tables T1 and T2, linear guides G11, G12, G21 and G22,
actuators A1 and
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13
A2, and rods RI and R2. Note that although each of the shape defining plates
102b, 102c and
102d also includes its driving mechanism as in the case of the shape defining
plate 102a, the
illustration of them is omitted in Figs. 6 and 7.
[0043]
As shown in Figs. 6 and 7, the shape defining plate 102a is placed and fixed
on the slide
table T1, which can be slid in the x-axis direction. The slide table T1 is
slidably placed on a pair
of linear guides G11 and G12 extending in parallel with the x-axis direction.
Further, the slide
table T1 is connected to the rod R1 extending from the actuator Al in the x-
axis direction. With
the above-described configuration, the shape defining plate 102a can be slid
in the x-axis
direction.
[0044]
Further, as shown in Figs. 6 and 7, the linear guides Gll and G12 and the
actuator Al
are placed and fixed on the slide table T2, which can be slid in the z-axis
direction. The slide
table T2 is slidably placed on a pair of linear guides G21 and G22 extending
in parallel with the
z-axis direction. Further, the slide table T2 is connected to the rod R2
extending from the
actuator A2 in the z-axis direction. The linear guides G21 and G22 and the
actuator A2 are fixed
on a horizontal floor surface or a horizontal pedestal (not shown). With the
above-described
configuration, the shape defining plate 102a can be slid in the z-axis
direction. Note that
examples of the actuators A1 and A2 include a hydraulic cylinder, an air
cylinder, and a motor.
[0045]
[Second exemplary embodiment]
Next, a free casting apparatus according to a second exemplary embodiment is
explained with reference to Fig. 8. Fig. 8 is a schematic cross section of a
free casting apparatus
according to the second exemplary embodiment. Note that the xyz-coordinate
system shown in
Fig. 8 also corresponds to that shown in Fig. 1. In the free casting apparatus
according to the
first exemplary embodiment, the gas blowing-up nozzle 104 is formed on the
shape defining
member 102. In contrast to this, in the free casting apparatus according to
the second exemplary
embodiment, a gas blowing-up nozzle(s) 204 is formed inside a shape defining
member 202. In
other words, a passage(s) for a blocking gas is formed inside the shape
defining member 202. In
the free casting apparatus according to the second exemplary embodiment, by
forming the
passage(s) for the blocking gas inside the shape defining member 202, the
space necessary for
the free casting apparatus is reduced in the second exemplary embodiment even
further than it is
in the first exemplary embodiment.
[0046]
CA 02908090 2015-09-25
14
In the free casting apparatus according to the second exemplary embodiment,
the gas
blowing-up nozzle 204 that blows a blocking gas in an obliquely upward
direction is disposed
inside the shape defining member 202. Meanwhile, similarly to the first
exemplary embodiment,
it is necessary that the place on the surface of the cast metal M3 on which
the blocking gas is
blown is located between the place on the surface of the cast metal M3 on
which the cooling gas
is blown and the solidification interface SIF. Note that the effect of the
angle 0 between the flux
of the blocking gas and the surface of the cast metal M3 is similar to that in
the first exemplary
embodiment. Therefore, the angle 0 is preferably equal to or less than 25
degrees.
[0047]
The cooling gas that has branched in the downward direction along the surface
of the
cast metal M3 can be blocked by the blocking gas blown up in an obliquely
upward direction
from the gas blowing-up nozzle 204 formed inside the shape defining member
202. As a result,
it is possible to prevent (or reduce) the occurrence of an undulation on the
surface of the held
molten metal M2 and improve the size accuracy and the surface quality of the
cast-metal article.
In addition, it is possible to increase the casting speed and improve the
productivity compared to
the related art by increasing the flow rate of the cooling gas. Further, the
blocking gas can
improve the cooling effect of the cast metal M3.
[0048]
[Third exemplary embodiment]
Next, a free casting apparatus according to a third exemplary embodiment is
explained
with reference to Fig. 9. Fig. 9 is a schematic cross section of a free
casting apparatus according
to the third exemplary embodiment. Note that the xyz-coordinate system shown
in Fig. 9 also
corresponds to that shown in Fig. 1. In the free casting apparatus according
to the first
exemplary embodiment, the gas blowing-up nozzle 104 is formed on the shape
defining member
102. In contrast to this, in the free casting apparatus according to the third
exemplary
embodiment, a blocking wall(s) (projection(s)) 302a for blocking the cooling
gas that has
branched in the downward direction along the surface of the cast metal M3 is
formed. The
blocking wall 302a is formed on a shape defining member near the end on the
side of the shape
defining member 302 where the molten-metal passage section 103 passes through.
[0049]
It should be noted that the height of the blocking wall 302a and distance
between the
molten-metal passage section 103 and the blocking wall 302a are determined
according to the
shape in the longitudinal direction of the cast metal M3. Specifically, the
higher the blocking
wall 302a is, the more the effect of blocking the downward-branched cooling
gas improves.
CA 02908090 2015-09-25
Further, the shorter the distance between the molten-metal passage section 103
and the blocking
wall 302a is, the more the effect of blocking the downward-branched cooling
gas improves.
However, the flexibility in the shape in the longitudinal direction of the
cast metal M3 decreases,
thus leading to the cast metal M3 extending on a straight line.
5 Note that there is no particular restriction on the width W of the
blocking wall 302a.
[0050]
Here, Fig. 10 is a schematic cross section of a free casting apparatus
according to a
modified example of the third exemplary embodiment. For example, as shown in
Fig. 10, the
blocking wall 302a may reach the outer edge (the end on the outer side) of the
shape defining
10 member 302.
[0051]
In the free casting apparatus according to the third exemplary embodiment, the
cooling
gas that has branched in the downward direction along the surface of the cast
metal M3 can be
blocked by the blocking wall 302a. As a result, it is possible to prevent (or
reduce) the
15 occurrence of an undulation on the surface of the held molten metal M2
and improve the size
accuracy and the surface quality of the cast-metal article. Further, it is
possible to increase the
casting speed and improve the productivity compared to the related art by
increasing the flow
rate of the cooling gas.
[0052]
[Fourth exemplary embodiment]
Next, a free casting apparatus according to a fourth exemplary embodiment is
explained
with reference to Fig. 11. Fig. 11 is a schematic cross section of a free
casting apparatus
according to the fourth exemplary embodiment. Note that the xyz-coordinate
system shown in
Fig. 11 also corresponds to that shown in Fig. 1. In the free casting
apparatus according to the
second exemplary embodiment, the gas blowing-up nozzle 204 is formed inside
the shape
defining member 202. Further, in the free casting apparatus according to the
third exemplary
embodiment, the blocking wall 302a is formed on the shape defining member 302.
In contrast to
this, in the free casting apparatus according to the fourth exemplary
embodiment, a gas blowing-
up nozzle(s) 404 is formed inside a shape defining member 402 and a blocking
wall(s) 402a. In
other words, a passage(s) for a blocking gas is formed inside the shape
defining member 402 and
the blocking wall(s) 402a. Further, tip(s) (blowing hole(s)) of the gas
blowing-up nozzle(s) 404
is formed on the top surface of the blocking wall(s) 402a.
[0053]
In the free casting apparatus according to the fourth exemplary embodiment,
the gas
CA 02908090 2015-09-25
16
blowing-up nozzle 404 that blows up a blocking gas in an obliquely upward
direction is disposed
inside the shape defining member 402 and the blocking wall 402a. Meanwhile,
similarly to the
first and second exemplary embodiments, it is necessary that the place on the
surface of the cast
metal M3 on which the blocking gas is blown is located between the place on
the surface of the
cast metal M3 on which the cooling gas is blown and the solidification
interface SIF. Note that
the effect of the angle 0 between the flux of the blocking gas and the surface
of the cast metal
M3 is similar to that in the first exemplary embodiment. Therefore, the angle
0 is preferably
equal to or less than 25 degrees.
[0054]
The cooling gas that has branched in the downward direction along the surface
of the
cast metal M3 can be blocked by both the blocking wall 402a and the blocking
gas blown up in
an obliquely upward direction from the inside of that blocking wall 402a. As a
result, it is
possible to prevent (or reduce) the occurrence of an undulation on the surface
of the held molten
metal M2 and improve the size accuracy and the surface quality of the cast-
metal article. In
addition, it is possible to increase the casting speed and improve the
productivity compared to
the related art by increasing the flow rate of the cooling gas. Further, the
blocking gas can
improve the cooling effect of the cast metal M3.
[0055]
Note that the present invention is not limited to the above-described
exemplary
embodiments, and various modifications can be made without departing the
spirit and scope of
the present invention.
Reference Signs List
[0056]
101 MOLTEN METAL HOLDING FURNACE
102, 202, 302, 402 SHAPE DEFINING MEMBER
102a-102d SHAPE DEFINING PLATE
103 MOLTEN-METAL PASSAGE SECTION
104, 204, 404 GAS BLOWING-UP NOZZLE
105 ACTUATOR
106 COOLING GAS NOZZLE
108 PULLING-UP MACHINE
302a, 402a BLOCKING WALL (PROJECTION)
Al, A2 ACTUATOR
CA 02908090 2015-09-25
17
G11, G12, G21, G22 LINEAR GUIDE
M1 MOLTEN METAL
M2 HELD MOLTEN METAL
M3 CAST METAL
R1, R2 ROD
S1 LASER DISPLACEMENT GAUGE
S2 LASER REFLECTOR PLATE
SIF SOLIDIFICATION INTERFACE
ST STARTER
T 1 , T2 SLIDE TABLE
