Note: Descriptions are shown in the official language in which they were submitted.
CA 02879339 2015-01-16
WO 2014/045115 PCT/1B2013/002129
UP-DRAWING CONTINUOUS CASTING APPARATUS AND UP-DRAWING
CONTINUOUS CASTING METHOD
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001]
The invention relates to an up-drawing continuous casting apparatus and
an up-drawing continuous casting method.
2. Description of Related Art
[0002] In Japanese Patent Application Publication No. 2012-61518 (JP
2012-61518 A), the inventors propose a free casting method as a groundbreaking
continuous casting method that does not require a mold. As described in JP
2012-61518
A, a starter is first immersed into the surface of molten metal (a molten
metal surfaCe), and
then when the starter is drawn up, molten metal is also drawn out following
the starter by
surface tension and the surface film of the molten metal. Here, a casting that
has a
desired sectional shape is able to be continuously cast by drawing out the
molten metal via
a shape determining member= arranged near the molten metal surface, and
cooling it (i.e.,
the drawn out molten metal).
[0003] With a
normal continuous casting method, the sectional shape and the =
shape in the longitudinal direction are both determined by a mold. In
particular, the
solidified metal (i.e., the casting) must pass through the mold, so the cast
casting takes on a
shape that extends linearly in the longitudinal direction.
In contrast, the shape
determining member in the free casting method determines only the sectional
shape of the
casting, the shape in the longitudinal direction is not determined. Also, the
shape
determining member is able to move in a direction parallel to the molten metal
surface (i.e.,
horizontally), so castings of various shapes in the longitudinal direction are
able to be
obtained. For example, JP 2012-61518 A describes a hollow casting (i.e., a
pipe) formed
in a zigzag shape or a helical shape, not a linear shape in the longitudinal
direction.
1
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
[0004]
The inventors discovered that with the free casting method described in JP
2012-61518 A, the molten metal drawn out via the shape determining member is
cooled by
only cooling gas, so the casting speed is slow, which is problematic in terms
of
productivity.
SUMMARY OF THE INVENTION
[0005]
The invention thus provides an up-drawing continuous casting apparatus
and an up-drawing continuous casting method that increases casting speed, and
thus offers
excellent productivity.
[0006] A first
aspect of the invention relates to an up-drawing continuous casting
apparatus. This up-drawing continuous casting apparatus includes a holding
furnace that
holds molten metal; a shape determining member that is arranged near a molten
metal
surface of the molten metal held in the holding furnace, and that determines a
sectional
shape of a casting by the molten metal passing through the shape determining
member; a
cooling portion that cools and solidifies the molten metal that has passed
through the shape
determining member; and a molten metal cooling portion that lowers a
temperature of the
molten metal held in the holding furnace.
[0007]
According to this first aspect, casting speed is able to be increased, so
productivity is able to be improved.
[0008] In the
first aspect described above, the molten metal cooling portion may
be provided directly below the shape determining member.
[0009]
With this structure, the temperature of the molten metal positioned directly
below the shape determining member is able to be lowered in a short period of
time, so the
casting speed is able to be increased.
[0010] The up-
drawing continuous casting apparatus of the first aspect described
above may also include an actuator that moves the molten metal cooling portion
in a
top-bottom direction inside the holding furnace.
[0011]
In the first aspect described above, cooling gas may pass through an inside
of the molten metal cooling portion.
2
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
[0012]
In the first aspect described above, the molten metal cooling portion may
be made of ceramic.
=
[0013] The up-drawing continuous casting apparatus of the first aspect
described
= above may also include a partition wall that surrounds the molten metal,
and an ambient
temperature regulating portion that regulates a temperature of an atmosphere
surrounded
by the partition wall.
[0014]
According to the first aspect described above, the quality of a casting is
able to be made stable.
[0015]
A second aspect of the invention relates to an up-drawing continuous
casting method that uses a casting apparatus having a shape determining member
that
determines a sectional shape of a casting, a holding furnace that holds a
molten metal, and
a molten metal cooling portion provided in the holding furnace. The up-drawing
continuous casting method includes arranging the shape determining member near
a
molten metal surface of the molten metal held in the holding furnace; lowering
a
temperature of the molten metal held in the holding furnace, with the molten
metal cooling
portion; passing the molten metal that has been lowered in temperature through
the shape
determining member and drawing up the molten metal; and cooling the molten
metal that
has passed through the shape determining member, and been drawn up.
[0016]
According to this second aspect, casting speed is able to be increased, so
productivity is able to be improved.
[0017] In the second aspect described above, the molten metal
cooling portion
may be provided directly below the shape determining member.
[0018] With this structure, the temperature of the molten metal
positioned directly
below the shape determining member is able to be lowered in a short period of
time, so the
casting speed is able to be increased.
[0019] The up-drawing continuous casting method of the second
aspect described
above may also include moving the molten metal cooling portion in a top-bottom
direction
inside the holding furnace.
= [0020] In the second aspect described above, lowering
the temperature of the
= 3
CA 02879339 2015-01-16
WO 2014/045115 PCT/1B2013/002129
molten metal may be done by leading cooling gas into the molten metal cooling
portion.
[0021]
In the second aspect described above, the molten metal cooling portion
may be made of ceramic.
[0022]
The up-drawing continuous casting method of the second aspect described
above may also include surrounding the molten metal with a partition wall, and
regulating
a temperature of an atmosphere surrounded by the partition wall.
[0023]
According to the second aspect described above, the quality of a casting is
able to be made stable.
[0024]
A third aspect of the invention relates to an up-drawing continuous casting
apparatus. This up-drawing continuous casting apparatus includes a holding
furnace that
holds molten metal; a shape determining member that is arranged near a molten
metal
surface of the molten metal held in the holding furnace, and that determines a
sectional
shape of a casting by the molten metal passing through the shape determining
member; and
a cooling portion that cools and solidifies the molten metal that has passed
through the
shape determining member with a starter. The starter has a cooling mechanism
that is
integrated with the starter.
[0025]
According to this third aspect, casting speed is able to be increased, so
productivity is able to be improved.
[0026]
In the third aspect described above, the cooling mechanism may include a
pipe that is attached to the starter and into which coolant is introduced.
[0027]
In the third aspect described above, the cooling mechanism may be the
starter itself that is formed by a pipe into which coolant is introduced.
[0028]
A fourth aspect of the invention relates to an up-drawing continuous
casting method that uses a casting apparatus having a shape determining member
that
determines a sectional shape of a casting, a holding furnace that holds a
molten metal, a
starter, and a cooling mechanism that is integrated with the starter. The up-
drawing
continuous casting method includes= arranging the shape determining member
near a
molten metal surface of the molten metal held in the holding furnace; passing
the molten
metal through the shape determining member and drawing up the molten metal
with the
4
CA 02879339 2015-01-16
WO 2014/045115 PCT/1B2013/002129
starter; cooling and solidifying the molten metal that has passed through the
shape
determining member and been drawn up; and cooling the starter with the cooling
mechanism.
[0029] According to this fourth aspect, casting speed is able to be
increased, so
productivity is able to be improved.
[0030] In the fourth aspect described above, the cooling mechanism
may be
formed by attaching a pipe to the starter and introducing coolant into the
pipe.
[0031] In the fourth aspect described above, the cooling mechanism
may be
formed by introducing coolant into the starter itself that is formed by a
pipe.
[0032] According to the first to the fourth aspects of the invention, it is
possible
to provide an up-drawing continuous casting apparatus and an up-drawing
continuous
casting method that increases casting speed, and thus offers excellent
productivity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Features, advantages, and technical and industrial significance of
exemplary embodiments of the invention will be described below with reference
to the
accompanying drawings, in which like numerals denote like elements, and
wherein:
FIG. 1 is a sectional view of a free casting apparatus according to a first
example
embodiment of the invention;
FIG. 2 is a plan view of an inner shape determining member and an outer shape
determining member;
FIG. 3 is a plan view of a detailed configuration example of a molten metal
cooler;
FIG. 4 is a plan view of another detailed configuration example of the molten
metal
cooler;
FIG. 5 is a sectional view, of a free casting apparatus according to a second
example
embodiment of the invention;
FIG. 6 is a sectional view of a free casting apparatus according to a third
example
embodiment of the invention; and
FIG. 7 is a sectional view of a free casting apparatus according to a fourth
example
5
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
embodiment of the invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0034]
Hereinafter, specific example embodiments to which the invention has
been applied will be described in detail with reference to the accompanying
drawings.
However, the invention is not limited to these example embodiments. Also, the
description and the drawings are simplified as appropriate to clarify the
invention. Terms
such as "top-bottom direction" and "left-right direction" and the like match
the top-bottom
and left-right directions in the drawings.
(First example embodiment)
[0035]
First, a free casting apparatus (up-drawing continuous casting apparatus)
according to a first example embodiment of the invention will be described
with reference
to FIG 1. FIG. 1 is a sectional view of the free casting apparatus according
to the first
example embodiment. As shown in FIG. 1, the free casting apparatus according
to the
first example embodiment includes a molten metal holding furnace 101, an inner
shape
determining member 102a, an outer shape determining member 102b, support rods
103 and
104, an actuator 105, a cooling gas nozzle 106, a molten metal cooler 107, a
coolant
conduit 108, and an actuator 109.
[0036]
The molten metal holding furnace 101 holds molten metal M1 such as
aluminum or an aluminum alloy, for example, and keeps it at a predetermined
temperature.
In the example in FIG. 1, molten metal M1 is not replenished into the molten
metal holding
furnace 101, so the surface of the molten metal M1 (i.e., the molten metal
level) drops as
casting proceeds. However, molten metal may also be instantly replenished into
the
molten metal holding furnace 101 during casting such that the molten metal
level is kept
26
constant. Naturally, the molten metal M1 may be another metal or alloy other
than
aluminum.
[0037] The inner shape determining member 102a and the outer shape
determining member 102b are made of ceramic or stainless steel, for example,
and are
arranged near the molten metal surface. In the example shown in FIG. 1, the
inner shape
6
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
determining member 102a and the outer shape determining member 102b are
arranged
contacting the molten metal surface. However, the inner shape determining
member 102a
and the outer shape determining member 102b may also be arranged with a main
surface
thereof that is on the lower side (i.e., the molten metal side) not contacting
the molten
metal surface. More specifically, a predetermined gap (such as approximately
0.5 mm)
may be provided between the molten metal surface and the lower-side main
surface of both
the inner shape determining member 102a and the outer shape determining member
102b.
[0038]
Moreover, the inner shape determining member 102a determines the inner
shape of a casting M3, and the outer shape determining member 102b determines
the outer
shape of the casting M3. The casting M3 shown in FIG 1 is a hollow casting
(i.e., a pipe)
with a tube-shaped cross-section in the left-right direction (hereinafter
referred to as
"transverse section"). That is, more specifically, the inner shape determining
member
102a determines an inner diameter of the transverse section of the casting M3,
and the
outer shape determining member 102b determines an outer diameter of the
transverse
section of the casting M3.
[0039]
FIG 2 is a plan view of the inner shape determining member 102a and the
outer shape determining member 102b. Here, the sectional view of the inner
shape
determining member 102a and the outer shape determining member 102b in FIG. 1
corresponds to the sectional view taken along line I ¨ I in FIG 2. As shown in
FIG 2, the
outer shape determining member 102b has a rectangular planar shape, for
example, and has
a circular open portion in the center portion. The inner shape determining
member 102a
has a circular planar shape, for example, and is arranged in the center
portion of the open
portion of the outer shape determining member 102b. A gap between the inner
shape
determining member 102a and the outer shape determining member 102b is a
molten metal
= 25 passage portion 102c through which molten metal passes. In this way,
the connecting
member 102 is formed by the inner shape determining member 102a, the outer
shape
determining member 102b, and the molten metal passage portion 102c.
[0040] As shown in FIG. 1, the molten metal M1 is drawn up
following the
casting M3 by the surface tension and the surface film of the molten metal,
and passes
7
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
through the molten metal passage portion 102c. Here, the molten metal that is
drawn up
from the molten metal surface following the casting M3 by the surface film and
the surface
tension of the molten metal will be referred to as "retained molten metal M2".
Also, the
interface between the casting M3 and the retained molten metal M2 is a
solidification
interface.
[0041]
The support rod 103 supports the inner shape determining member 102a
and the support rod 104 supports the outer shape determining member 102b. The
positional relationship between the inner shape determining member 102a and
the outer
shape determining member 102b is able to be maintained by these support rods
103 and
104. Here, having the support rod 103 be a pipe structure, flowing cooling gas
through
the support rod 103, and moreover, providing blow holes in the inner shape
determining
member 102a, enables the casting M3 to be cooled from the inside as well.
[0042]
The support rods 103 and 104 are both connected to the actuator 105.
This actuator 105 enables the support rods 103 and 104 to move in the top-
bottom
direction (the perpendicular direction) and the left-right direction, while
maintaining the
positional relationship between the inner shape determining member 102a and
the outer
shape determining member 102b. According to this kind of structure, the inner
shape
determining member 102a and the outer shape determining member 102b are able
to be
moved downward as the molten metal level drops as casting progresses. Also,
the inner
shape determining member 102a and the outer shape determining member 102b are
able to
be moved in the left-right direction, so the shape of the casting M3 in the
longitudinal
direction is able to be changed freely.
[0043]
A cooling gas nozzle (a cooling portion) 106 is used to spray cooling gas
(e.g., air, nitrogen, argon, or the like) at the casting M3 to cool the
casting M3. The
casting M3 is cooled by the cooling gas while being drawn up by a drawer, not
shown, that
is connected to a starter ST. Accordingly, the retained molten metal M2 near
the
solidification interface solidifies sequentially, thus forming the casting M3.
Here, in
order to increase the heat removal from the casting M3 and thus increase the
casting speed,
the temperature of the cooling gas is preferably made as low as possible. For
example, an
8
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
extremely low temperature gas such as cooling gas that has been cooled by
liquefied gas or
cooling gas of liquefied gas (e.g., liquid nitrogen or liquid argon) has been
vaporized may
be used.
[0044]
The molten metal cooler (a molten metal cooling portion) 107 is designed
to lower the temperature of the molten metal M1 positioned directly below the
inner shape
determining member 102a and the outer shape determining member 102b. Coolant
is
circulated through the molten metal cooler 107 only when the temperature of
the molten
metal M1 is to be lowered. The provision of the molten metal cooler 107 is one
characteristic of the free casting apparatus according to this example
embodiment.
=
[0045] The
coolant conduit 108 introduces the coolant into the molten metal
cooler 107, circulates the coolant through the molten metal cooler 107, and
leads the
coolant that has removed the heat from the molten metal M1 out of the molten
metal cooler
107. Also, the coolant conduit 108 supports the molten metal cooler 107. The
coolant is
not particularly limited, but from the viewpoint of safety, cooling gas (e.g.,
air, nitrogen,
argon, or the like) is preferable. Also, as a method for circulating the
coolant, a .
suction-type method is more preferable than a pressure-type method from the
viewpoint of
safety.
[0046]
The material of the molten metal cooler 107 and the coolant conduit 108 is
not particularly limited. For example, the material may be ceramic or
stainless steel.
Also, when stainless steel is used, it is preferable to prepare against molten
metal loss, e.g.,
to wrap heat-resistant tape around the portion that contacts the molten metal
M1.
[0047]
FIG. 3 is a plan view of a detailed configuration example of the molten
metal cooler 107. In FIG. 3, the inner shape determining member 102a and the
support
rod 103 are both shown by dotted lines to facilitate understanding of the
planar positional
relationship. The molten metal cooler 107 shown in FIG 3 is formed by a single
coiled
pipe. That is, the molten metal cooler 107 and the coolant conduit 108 are
integrally
formed. As shown in FIG. 3, a circular open portion is formed in the center
portion of the
molten metal cooler 107. The support rod 103 passes through this open portion.
This
kind of structure inhibits interference between the support rod 103 and the
molten metal
9
CA 02879339 2015-01-16
WO 2014/045115 PCT/1B2013/002129
cooler 107.
[0048]
FIG 4 is a plan view of another detailed configuration example of the
molten metal cooler 107. In FIG 4 as well, the inner shape determining member
102a
and the support rod 103 are both shown by dotted lines to facilitate
understanding of the
planar positional relationship. The molten metal cooler 107 shown in FIG. 4 is
formed by
a single winding pipe (the entire pipe is serpentine-like), with linear
portions 107a and
U-shaped portions 107b alternately repeating. That is, the molten metal cooler
107 and
the coolant conduit 108 are integrally formed. As shown in FIG 4, at the
center portion
of the molten metal cooler 107, the interval between two adjacent linear
portions 107a is
larger, and the support rod 103 passes through here. This kind of structure
inhibits
interference between the support rod 103 and the molten metal cooler 107. The
structure
of the molten metal cooler 107 shown in FIGS. 3 and 4 is only one example.
Various
other configuration examples are also possible.
[0049]
The coolant conduit 108 is connected to the actuator 109. As shown in
FIG 1, the actuator 109 enables the molten metal cooler 107 to move in a top-
bottom
direction in the molten metal Ml. The molten metal cooler 107 is also able to
be moved
in the left-right direction to conform to the inner shape determining member
102a and the
outer shape determining member 102b.
[0050]
When the temperature of the molten metal M1 positioned directly below
the inner shape determining member 102a and the outer shape determining member
102b
is to be lowered, coolant may be circulated inside the molten metal cooler
107, and the
molten metal cooler 107 may be raised so that it moves closer to the inner
shape
determining member 102a and the outer shape determining member 102b. On the
other
hand, in any other case, circulation of the coolant in the molten metal cooler
107 may be
stopped, and the molten metal cooler 107 may be lowered so that it moves away
from the
inner shape determining member 102a and the outer shape determining member
102b.
[0051]
Next, the effects of the molten metal cooler 107 will be described in detail.
= The temperature of the molten metal M1 is always maintained at a
predetermined
appropriate temperature by the molten metal holding furnace 101. Here, the
appropriate
10 =
CA 02879339 2015-01-16
WO 2014/045115 PCT/1B2013/002129
temperature is a temperature for keeping the solidification interface at an
appropriate
height. The height of the solidification interface is maintained by a balance
between heat
removal from the casting M3 and up-drawing speed. For example, when the
thickness of
the casting M3 is thick during casting, the heat capacity of the retained
molten metal M2
increases, so the balance becomes off, the position of the solidification
interface rises, and
the desired shape becomes difficult to obtain. That is, moldability
deteriorates.
[0052] At this time,
in order to return the position of the solidification interface to
the original appropriate height, if the heat removal from the casting M3 is
unable to be
increased, the casting speed must be slowed or the temperature of the molten
metal M1
must be lowered. In order to lower the temperature of the molten metal Ml, all
that need
be done is to lower the set temperature of the molten metal holding furnace
101.
However, it takes time for all of the molten metal M1 to actually drop to the
set
temperature. With the free casting apparatuses until now, the casting speed
had to be
slowed until the temperature of all of the molten metal M1 dropped to the set
temperature.
[0053] In contrast,
the free casting apparatus according to this example
embodiment is provided with the molten metal cooler 107, so the temperature of
the
molten metal M1 can be lowered in a short period of time. In particular, the
molten metal
cooler 107 is positioned directly below the inner shape determining member
102a and the
outer shape determining member 102b, so the temperature of only the molten
metal M1
near the inner shape determining member 102a and the outer shape determining
member
102b (or more specifically, directly below the inner shape determining member
102a and
the outer shape determining member 102b) is able to be lowered in a short
period of time.
Therefore, the casting speed does not need to be slowed, so the casting speed
can be faster
than it is with the free casting apparatuses until now. As a result, the
casting time is
shorter, so productivity is improved.
[0054] Next, the free
casting method according to the first example embodiment
will be described with reference to FIG. 1. First, the starter ST is lowered
so that it passes
through the molten metal passage portion 102c between the inner shape
determining
member 102a and the outer shape determining member 102b, and the tip end of
the starter
11
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
ST is immersed in the molten metal Ml.
[0055]
Next, the starter ST starts to be drawn up at a predetermined speed. Here,
when the starter ST separates from the molten metal surface, the retained
molten metal M2
that follows the starter ST and is drawn up from the molten metal surface by
the surface
film and surface tension is formed. As shown in FIG. 1, the retained molten
metal M2 is
formed in the molten metal passage portion 102c between the inner shape
determining
member 102a and the outer shape determining member 102b. That is, the inner
shape
determining member 102a and the outer shape determining member 102b give the
retained
molten metal M2 its shape.
[0056] Next, the
starter ST is cooled by cooling gas blown from the cooling gas
nozzle 106, so the retained molten metal M2 solidifies sequentially from the
upper side
toward the lower side, thus forming the casting M3. In this way, the casting
M3 is able to
be continuously cast.
(Second example embodiment)
[0057] Next, a
free casting apparatus according to a second example embodiment
of the invention will be described with reference to FIG. 5. FIG. 5 is a
sectional view of
the free casting apparatus according to the second example embodiment. As
shown in
FIG. 5, the free casting apparatus according to the second example embodiment
includes a
molten metal holding furnace 101, an inner shape determining member 102a, an
outer
shape determining member 102b, support rods 103 and 104, an actuator 105, a
cooling gas
nozzle 106, a molten metal cooler 107, a coolant conduit 108, an actuator 109,
a partition
wall 110, and an ambient temperature regulating portion 111. That is, the
partition wall
110 and the ambient temperature regulating portion 111 are added to the free
casting
apparatus according to the first example embodiment shown in FIG. 1. The other
structure is the smite as it is in the first example embodiment, so a
description thereof will
be omitted.
[0058] As shown in FIG 5, with the free casting apparatus according
to the
second example embodiment, the molten metal M1 and the casting M3 are housed
in a
space partitioned off by the partition wall 110. Also, the ambient temperature
regulating
12
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
portion 111 is provided on a ceiling portion of the partition wall 110. ,
[0059]
According to this kind of structure, the temperature in the space
partitioned off by the partition wall 110 is maintained at a predetermined
temperature (such
as 25 C for example) by the ambient temperature regulating portion 111.
Because the
temperature of the atmosphere of the molten metal M1 and the casting M3 is
kept constant,
the quality of the casting M3 is able to be more stable than it is with the
free casting
apparatus according to the first example embodiment. Also, by keeping the
temperature
of the atmosphere at 25 C, for example, the temperature of the atmosphere
drops farther
than it does when the temperature of the atmosphere is not controlled, so the
casting speed
is able to be faster than is with the free casting apparatus according to the
first example
embodiment. The location where the ambient temperature regulating portion 111
is
arranged is not particularly limited. Also, as shown in FIG. 5, an air flow
port 110a may
be provided in an upper portion of the partition wall 110 so that heated air
trapped inside
the partitioned space is able to escape.
(Third example embodiment)
[0060]
Next, a free casting apparatus according to a third example embodiment of
the invention will be described with reference to FIG. 6. FIG 6 is a sectional
view of the
free casting apparatus according to the third example embodiment. As shown in
FIG 6,
the free casting apparatus according to the third example embodiment includes
a molten
metal holding furnace 101, an inner shape determining member 102a, an outer
shape
determining member 102b, support rods 103 and 104, an actuator 105, a cooling
gas nozzle
106, and a coolant conduit 112. That is, the molten metal cooler 107, the
coolant conduit
=
108, and the actuator 109 in the fret casting apparatus according to the first
example
embodiment shown in FIG 1 are not provided, and instead, the coolant conduit
112 is
provided. The other structure is the same as it is in the first example
embodiment, so a
description thereof will be omitted.
[0061]
As shown in FIG 6, the free casting apparatus according to the third
example embodiment includes the coolant conduit (a cooling mechanism) 112 that
is
wound in a helical shape around a starter ST. That is, the free casting
apparatus according
' 13
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
to the third example embodiment has a cooling mechanism that is integrated
with the
starter ST. According to this kind of structure, the starter ST is cooled. The
coolant is
not particularly limited, but cooling gas (e.g., air, nitrogen, argon, or the
like), or cooling
water may be used, for example. Cooling the starter ST enables heat removal
from the
casting M3 to be increased and casting speed to be faster while retaining good
moldability.
[0062]
Of course, the casting speed may be increased even more by combining
the first example embodiment with the third example embodiment, or the second
example
embodiment with the third example embodiment.
(Fourth example embodiment)
[0063] Next, a
free casting apparatus according to a fourth example embodiment
of the invention will be described with reference to FIG. 7. FIG. 7 is a
sectional view of
the free casting apparatus according to the fourth example embodiment. As
shown in FIG.
7, the free casting apparatus according to the fourth example embodiment
includes a
= molten metal holding furnace 101, an outer shape determining member 102b,
a support rod
104, an actuator 105, and a cooling gas nozzle 106. That is, the inner shape
determining
member 102a, the support rod 103, and the coolant conduit 112 in the free
casting
apparatus according to the third example embodiment shown in FIG. 6 are not
provided.
On the other hand, the starter ST itself is a coolant conduit (a cooling
mechanism). That
is, the free casting apparatus according to the fourth example embodiment is
also provided
with a cooling mechanism that is integrated with the starter ST. The other
structure is the
same as it is in the third example embodiment, so a description thereof will
be omitted.
[0064]
As shown in FIG. 7, the casting M3 cast with the free casting apparatus
according to the fourth example embodiment is a solid structure (a rod), not a
hollow
structure (a pipe). Therefore, the inner shape determining member 102a is not
used.
= 25 Only the outer shape determining member 102b according to the example
embodiment
described above is used. In this case, the open portion provided in the outer
shape
determining member 102b as it is serves as a molten metal passage portion
102c.
[0065]
With the free casting apparatus according to the fourth example
embodiment, the starter ST itself is the coolant conduit, so the starter ST is
cooled. The
14
CA 02879339 2015-01-16
WO 2014/045115
PCT/1B2013/002129
coolant is not particularly limited, but cooling gas (e.g., air, nitrogen,
argon, or the like)
may be used, for example. Also, the flow rate of the coolant may be controlled
at the
start of casting and during casting. More specifically, the flow rate of the
coolant may be
lower at the start of casting than it is during casting. Furthermore, during
casting (i.e.,
after casting has progressed to some extent), cooling water may also be used.
Also,
cooling gas may be used at the start of casting, and cooling water may be used
during
casting.
[0066]
With the free casting apparatus according to the fourth example
embodiment, cooling the starter ST enables heat removal from the casting M3 to
be
increased and casting speed to be faster, just like the third example
embodiment. Also,
because the starter ST is cooled, material with a lower melting point than the
molten metal
temperature may be used as the starter ST. Furthermore, the coolant
temperature on the
inlet side and the coolant temperature on the outlet side may be monitored and
fed back to
the casting control. After casting, heat treatment for texture control may be
performed by
circulating heat treating oil instead of coolant through the starter ST.
[0067]
Also, a normal starter ST is removed after casting, but the starter ST
according to the fourth example embodiment is able to be used as it is as a
product. For
example, pipe for a heat exchanger may be used as the normal starter ST.
Furthermore,
an even more complicated cooling circuit may also be used as the starter ST.
Also, a
casting that includes a pipe therein can also be formed by immersing the
starter ST in the
molten metal.
[0068]
Of course, the casting speed may be increased even more by combining
the first example embodiment with the fourth example embodiment, or the second
example
embodiment with the fourth example embodiment.
[0069] The
invention is not limited to the example embodiments described above,
and may be modified as appropriate.
