U.S. patent application number 14/783015 was filed with the patent office on 2016-03-10 for upward continuous casting apparatus and upward continuous casting method.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. The applicant listed for this patent is TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Yusei KUSAKA, Naoaki SUGIURA.
Application Number | 20160067771 14/783015 |
Document ID | / |
Family ID | 50630826 |
Filed Date | 2016-03-10 |
United States Patent
Application |
20160067771 |
Kind Code |
A1 |
KUSAKA; Yusei ; et
al. |
March 10, 2016 |
UPWARD CONTINUOUS CASTING APPARATUS AND UPWARD CONTINUOUS CASTING
METHOD
Abstract
An upward continuous casting apparatus includes a molten metal
retaining furnace that retains a molten metal, a draw-out part that
draws out the molten metal from a melt surface of the molten metal
that is retained in the molten metal retaining furnace, a
shape-defining member that is located in the vicinity of the melt
surface and defines a cross-sectional shape of a casting to be cast
by applying an external force to a retained molten metal that has
been drawn out by the draw-out part, and a solid heat transfer
member that is placed to contact a surface of the casting that is
formed through the shape-defining member.
Inventors: |
KUSAKA; Yusei; (Toyota-shi,
JP) ; SUGIURA; Naoaki; (Takahama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOYOTA JIDOSHA KABUSHIKI KAISHA |
Toyota-shi, |
|
JP |
|
|
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
|
Family ID: |
50630826 |
Appl. No.: |
14/783015 |
Filed: |
April 8, 2014 |
PCT Filed: |
April 8, 2014 |
PCT NO: |
PCT/IB2014/000493 |
371 Date: |
October 7, 2015 |
Current U.S.
Class: |
164/483 ;
164/418; 164/443 |
Current CPC
Class: |
B22D 11/145 20130101;
B22D 11/041 20130101; B22D 11/1243 20130101; B22D 11/1245
20130101 |
International
Class: |
B22D 11/14 20060101
B22D011/14; B22D 11/041 20060101 B22D011/041; B22D 11/124 20060101
B22D011/124 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 10, 2013 |
JP |
2013-082312 |
Claims
1. An upward continuous casting apparatus, comprising: a retaining
furnace that retains a molten metal; a draw-out part that draws out
the molten metal from a melt surface of the molten metal that is
retained in the retaining furnace; a shape-defining member that
defines a cross-sectional shape of a casting to be cast by applying
an external force to a retained molten metal which is a
unsolidified molten metal that has been drawn out by the draw-out
part, the shape-defining member being located in the vicinity of
the melt surface; and a solid heat transfer member that is placed
to contact a surface of the casting that is formed by
solidification of the retained molten metal.
2. The upward continuous casting apparatus according to claim 1,
wherein the solid heat transfer member is placed to contact a
surface of the casting in the vicinity of an interface between the
retained molten metal and the casting.
3. The upward continuous casting apparatus according to claim 1,
wherein the solid heat transfer member has a shape that corresponds
to the cross-sectional shape of the casting at a portion of the
solid heat transfer member placed into contact with the
casting.
4. The upward continuous casting apparatus according to claim 1,
wherein the solid heat transfer member has a curved surface shape
at a portion of the solid heat transfer member placed into contact
with the casting.
5. The upward continuous casting apparatus according to claim 1,
wherein the solid heat transfer member has the shape of a circular
column that is rotatable in a direction in which the casting is
pulled up.
6. The upward continuous casting apparatus according to claim 5,
further comprising a cooling part through which cooling water is
circulated in the solid heat transfer member, wherein the cooling
part has a bucket that scoops up the cooling water as the solid
heat transfer member rotates.
7. The upward continuous casting apparatus according to claim 1,
further comprising a cooling part through which a cooling medium is
circulated in the solid heat transfer member.
8. The upward continuous casting apparatus according to claim 1,
further comprising a cooling nozzle that blows a cooling medium
onto an upper surface of the solid heat transfer member.
9. The upward continuous casting apparatus according to claim 1,
further comprising a supporting member that biases the solid heat
transfer member into contact with a surface of the casting.
10. The upward continuous casting apparatus according to claim 9,
wherein the supporting member is a spring.
11. The upward continuous casting apparatus according to claim 1,
wherein the solid heat transfer member has a metal wool at a
portion of the solid heat transfer member placed into contact with
the casting.
12. The upward continuous casting apparatus according to claim 1,
wherein the solid heat transfer member is made of copper or a
copper alloy.
13. The upward continuous casting apparatus according to claim 1,
further comprising an actuator that moves the solid heat transfer
member in response to a movement of the shape-defining member.
14. The upward continuous casting apparatus according to claim 1,
wherein, when a starter is pulled up from the melt surface, the
molten metal is pulled up from the melt surface following the
starter by a surface film or surface tension thereof to form a
retained molten metal, a shape is imparted to the retained molten
metal by the shape-defining member, and the retained molten metal
is solidified from top to bottom to form a casting.
15. An upward continuous casting method, comprising: placing a
shape-defining member that defines a cross-sectional shape of a
casting to be cast in the vicinity of a melt surface of a molten
metal that is retained in a retaining furnace; pulling up the
molten metal through the shape-defining member; and cooling the
casting by placing a solid heat transfer member into contact with a
surface of the casting that is formed by solidification of the
molten metal that has been passed through the shape-defining
member:
16. The upward continuous casting method according to claim 15,
wherein the solid heat transfer member is placed into contact with
a surface of the casting in the vicinity of a interface between a
retained molten metal which is a unsolidified molten metal that has
been pulled up and the casting.
17. The upward continuous casting method according to claim 15,
wherein the solid heat transfer member has a shape that corresponds
to the cross-sectional shape of the casting at a portion of the
solid heat transfer member placed into contact with the
casting.
18. The upward continuous casting method according to claim 15,
wherein the solid heat transfer member has a curved surface shape
at a portion of the solid heat transfer member placed into contact
with the casting.
19. The upward continuous casting method according to claim 15,
wherein the solid heat transfer member has the shape of a circular
column that is rotatable in a direction in which the casting is
pulled up.
20. The upward continuous casting method according to claim 19,
wherein a cooling part through which cooling water is circulated is
further provided in the solid heat transfer member, and a bucket
that scoops up the cooling water as the solid heat transfer member
rotates is provided in the cooling part.
21. The upward continuous casting method according to claim 15,
wherein a cooling part through which a cooling medium is circulated
is further provided in the solid heat transfer member.
22. The upward continuous casting method according to claim 15,
wherein a cooling nozzle that blows a cooling medium onto an upper
surface of the solid heat transfer member is further provided.
23. The upward continuous casting method according to claim 15,
wherein a supporting member that biases the solid heat transfer
member into contact with a surface of the casting is further
provided.
24. The upward continuous casting method according to claim 23,
wherein the supporting member is a spring.
25. The upward continuous casting method according to claim 15,
wherein a metal wool is further provided at a portion of the solid
heat transfer member placed into contact with the casting.
26. The upward continuous casting method according to claim 15,
wherein the solid heat transfer member is made of copper or a
copper alloy.
27. The upward continuous casting method according to claim 15,
wherein the solid heat transfer member is moved in response to a
movement of the shape-defining member.
28. The upward continuous casting method according to claim 15,
wherein, when a starter is pulled up from the melt surface, the
molten metal is pulled up from the melt surface following the
starter by a surface film or surface tension thereof to form a
retained molten metal, a shape is imparted to the retained molten
metal by the shape-defining member, and the retained molten metal
is solidified from top to bottom to form a casting.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an upward continuous
casting apparatus and an upward continuous casting method.
[0003] 2. Description of Related Art
[0004] In Japanese Patent Application Publication No. 2012-61518
(JP 2012-61518 A), a free casting method is proposed by the present
inventors as an epoch-making continuous casting method that does
not require a mold. As shown in JP 2012-61518 A, when a starter is
pulled up after it is immersed into the surface of a metal melt
(molten metal) (in other words, the melt surface), the molten metal
is also drawn out following the starter by the surface film or
surface tension of the molten metal. Here, by drawing out the
molten metal through a shape-defining member that is located in the
vicinity of the melt surface and cooling the molten metal, a
casting with a desired cross-sectional shape can be cast
continuously.
[0005] In an ordinary continuous casting method, not only the
cross-sectional shape but also the longitudinal shape is defined by
a mold. In particular, the casting that is produced by a continuous
casting method has a shape that is linearly elongated in its
longitudinal direction because the solidified metal (in other
words, the casting) must be passed through a mold. In contrast, a
shape-defining member that is used in a free casting method defines
only the cross-sectional shape of the casting and does not define
the longitudinal shape of the casting. In addition, because the
shape-defining member is movable in directions parallel to the melt
surface (in other words, horizontal directions), castings with
different longitudinal shapes can be obtained. For example, a
hollow casting (in other words, a pipe) that is formed to have a
zigzag or spiral, not linear, configuration along its length is
disclosed in JP 2012-61518 A.
[0006] In the free casting method that is described in JP
2012-61518 A, the unsolidified molten metal that has been pulled up
from the melt surface following the starter (retained molten metal)
is swung by a cooling medium that is blown out of a cooling nozzle.
Thus, in the free casting method that is described in JP 2012-61518
A, it is necessary to prevent the retained molten metal from being
swung by lowering the pressure of the cooling medium that is blown
out of the cooling nozzle or moving the cooling nozzle away from
the retained molten metal. Thus, in the free casting method that is
described in JP 2012-61518 A, there is a possibility that the speed
at which the starter is pulled up cannot be increased because the
solidification rate of the retained molten metal is lowered.
SUMMARY OF THE INVENTION
[0007] The present invention provides an upward continuous casting
apparatus and an upward continuous casting method in which the
speed at which the starter is pulled up can be increased by quickly
cooling the casting without swinging the retained molten metal.
[0008] An upward continuous casting apparatus according to one
aspect of the present invention includes: a retaining furnace that
retains a molten metal; a draw-out part that draws out the molten
metal from a melt surface of the molten metal that is retained in
the retaining furnace; a shape-defining member that is located in
the vicinity of the melt surface and defines a cross-sectional
shape of a casting to be cast by applying an external force to a
retained molten metal which is the unsolidified molten metal that
has been drawn out by the draw-out part; and a solid heat transfer
member that is placed to contact a surface of the casting that is
formed by solidification of the retained molten metal. Thus, the
casting can be cooled quickly without swinging the retained molten
metal. This allows the speed at which the starter is pulled up to
be increased.
[0009] The solid heat transfer member may be placed to contact a
surface of the casting in the vicinity of a interface between the
retained molten metal and the casting.
[0010] The solid heat transfer member may have a shape that
corresponds to the cross-sectional shape of the casting at a
portion of the solid heat transfer member placed into contact with
the casting.
[0011] The solid heat transfer member may have a curved surface
shape at a portion t of the solid heat transfer member placed into
contact with the casting.
[0012] The solid heat transfer member may have the shape of a
circular column that is rotatable in a direction in which the
casting is pulled up.
[0013] The upward continuous casting apparatus may further include
a cooling part through which cooling water is circulated in the
solid heat transfer member. The cooling part may have a bucket that
scoops up the cooling water as the solid heat transfer member
rotates.
[0014] The upward continuous casting apparatus may further include
a cooling part through which a cooling medium is circulated in the
solid heat transfer member.
[0015] The upward continuous casting apparatus may further include
a cooling nozzle that blows a cooling medium onto an upper surface
of the solid heat transfer member.
[0016] The upward continuous casting apparatus may further include
a supporting member that biases the solid heat transfer member into
contact with a surface of the casting.
[0017] The supporting member may be a spring.
[0018] The solid heat transfer member may have a metal wool at a
portion of the solid heat transfer member placed into contact with
the casting.
[0019] The solid heat transfer member may be made of copper or a
copper alloy.
[0020] The upward continuous casting apparatus may further include
an actuator that moves the solid heat transfer member in response
to a movement of the shape-defining member.
[0021] When a starter is pulled up from the melt surface, the
molten metal may be pulled up from the melt surface following the
starter by a surface film or surface tension thereof to form a
retained molten metal. A shape may be imparted to the retained
molten metal by the shape-defining member. The retained molten
metal may be solidified from top to bottom to form a casting.
[0022] An upward continuous casting method according to one aspect
of the present invention includes the steps of: placing a
shape-defining member that defines a cross-sectional shape of a
casting to be cast in the vicinity of a melt surface of a molten
metal that is retained in a retaining furnace; pulling up the
molten metal through the shape-defining member; and cooling the
casting by placing a solid heat transfer member into contact with a
surface of the casting that is formed by solidification of the
molten metal that has been passed through the shape-defining
member. Thus, the casting can be cooled quickly without swinging
the retained molten metal. This allows the speed at which the
starter is pulled up to be increased.
[0023] The solid heat transfer member may be placed into contact
with a surface of the casting in the vicinity of a interface
between a retained molten metal which is the unsolidified molten
metal that has been pulled up and the casting.
[0024] The solid heat transfer member may have a shape that
corresponds to the cross-sectional shape of the casting at a
portion of the solid heat transfer member placed into contact with
the casting.
[0025] The solid heat transfer member may have a curved surface
shape at a portion of the solid heat transfer member placed into
contact with the casting.
[0026] The solid heat transfer member may have the shape of a
circular column that is rotatable in a direction in which the
casting is pulled up.
[0027] A cooling part through which cooling water is circulated may
be further provided in the solid heat transfer member, and a bucket
that scoops up the cooling water as the solid heat transfer member
rotates may be provided in the cooling part.
[0028] A cooling part through which a cooling medium is circulated
may be further provided in the solid heat transfer member.
[0029] A cooling nozzle that blows a cooling medium onto an upper
surface of the solid heat transfer member may be further
provided.
[0030] A supporting member that biases the solid heat transfer
member into contact with a surface of the casting may be further
provided.
[0031] The supporting member may be a spring.
[0032] A metal wool may be further provided at a portion of the
solid heat transfer member placed into contact with the
casting.
[0033] The solid heat transfer member may be made of copper or a
copper alloy.
[0034] The solid heat transfer member may be moved in response to a
movement of the shape-defining member.
[0035] When a starter is pulled up from the melt surface, the
molten metal may be pulled up from the melt surface following the
starter by a surface film or surface tension thereof to form a
retained molten metal. A shape may be imparted to the retained
molten metal by the shape-defining member. The retained molten
metal may be solidified from top to bottom to form a casting.
[0036] According to one aspect of the present invention, it is
possible to provide an upward continuous casting apparatus and an
upward continuous casting method in which the speed at which the
starter is pulled up can be increased by quickly cooling the
casting without swinging the retained molten metal.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] 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:
[0038] FIG. 1 is a cross-sectional view that illustrates a
configuration example of a free casting apparatus according to a
first embodiment;
[0039] FIG. 2 is a plan view of a shape-defining member that is
provided in the free casting apparatus that is shown in FIG. 1;
[0040] FIG. 3 is an enlarged cross-sectional view that illustrates
a first modification of the free casting apparatus according to the
first embodiment;
[0041] FIG. 4 is an enlarged cross-sectional view that illustrates
a second modification of the free casting apparatus according to
the first embodiment;
[0042] FIG. 5 is an enlarged cross-sectional view that illustrates
a configuration example of a free casting apparatus according to a
second embodiment;
[0043] FIG. 6 is an enlarged cross-sectional view that illustrates
a first modification of the free casting apparatus according to the
second embodiment;
[0044] FIG. 7 is an enlarged cross-sectional view that illustrates
a second modification of the free casting apparatus according to
the second embodiment;
[0045] FIG. 8 is an enlarged cross-sectional view that illustrates
a configuration example of a free casting apparatus according to a
third embodiment;
[0046] FIG. 9 is an enlarged cross-sectional view that illustrates
a first modification of the free casting apparatus according to the
third embodiment;
[0047] FIG. 10 is an enlarged cross-sectional view that illustrates
a second modification of the free casting apparatus according to
the third embodiment;
[0048] FIG. 11 is an enlarged cross-sectional view that illustrates
a configuration example of a free casting apparatus according to a
fourth embodiment;
[0049] FIG. 12 is an enlarged cross-sectional view that illustrates
a first modification of the free casting apparatus according to the
fourth embodiment;
[0050] FIG. 13 is an enlarged cross-sectional view that illustrates
a second modification of the free casting apparatus according to
the fourth embodiment;
[0051] FIG. 14 is an enlarged cross-sectional view that illustrates
a configuration example of a free casting apparatus according to a
fifth embodiment;
[0052] FIG. 15 is a cross-sectional view of the free casting
apparatus that is shown in FIG. 14 along the line II-II;
[0053] FIG. 16 is an enlarged cross-sectional view of a cooling
part that is provided in the free casting apparatus that is shown
in FIG. 14;
[0054] FIG. 17 is a cross-sectional view that illustrates another
configuration example of a free casting apparatus according to the
present invention; and
[0055] FIG. 18 is a plan view of a shape-defining member that is
provided in the free casting apparatus that is shown in FIG.
17.
DETAILED DESCRIPTION OF EMBODIMENTS
[0056] Description is hereinafter made of specific embodiments to
which the present invention is applied with reference to the
drawings. It should be noted that the present invention is not
limited to the following embodiments. The following description and
the drawings are simplified as needed to clarify the
description.
[0057] <First Embodiment> A free casting apparatus (upward
continuous casting apparatus) according to a first embodiment is
first described with reference to FIG. 1. FIG. 1 is a
cross-sectional view that illustrates a configuration example of a
free casting apparatus according to a first embodiment. As shown in
FIG. 1, the free casting apparatus according to the first
embodiment includes a molten metal retaining furnace (retaining
furnace) 101, an external shape-defining member 102a, a supporting
rod 103, an actuator 105, a draw-out part 107, solid heat transfer
members 108, and supporting members 109.
[0058] The molten metal retaining furnace 101 retains a molten
metal M1 of aluminum or an aluminum alloy, for example, and
maintains the molten metal M1 at a prescribed temperature. In the
example that is shown in FIG. 1, the surface level of the molten
metal M1 (in other words, the melt surface) is lowered as the
casting proceeds because the molten metal retaining furnace 101 is
not replenished with molten metal during casting. However, a
configuration in which the molten metal retaining furnace 101 is
replenished with molten metal during casting to maintain the melt
surface level constant is also possible. It should be appreciated
that the molten metal M1 may be a melt of a metal other than
aluminum or an alloy thereof.
[0059] The external shape-defining member 102a is made of ceramic
or stainless steel, for example, and is located in the vicinity of
the melt surface. In the example that is shown in FIG. 1, the
external shape-defining member 102a is placed to contact the melt
surface. However, the external shape-defining member 102a may be
located with the principal surface thereof on its lower side (on
the side that faces the melt surface) away from the melt surface.
Specifically, a prescribed (approximately 0.5 mm, for example) gap
may be provided between the principal surface of the external
shape-defining member 102a on its lower side and the melt
surface.
[0060] The external shape-defining member 102a defines the external
shape of a casting M3 to be cast. The casting M3 that is shown in
FIG. 1 is a rectangular column-shaped casting that has a
rectangular shape in a horizontal cross-section (which is
hereinafter referred to as "transverse cross-section"). More
specifically, the external shape-defining member 102a defines the
external shape of the transverse cross-section of the casting
M3.
[0061] FIG. 2 is a plan view of the external shape-defining member
102a. The cross-sectional view of the external shape-defining
member 102a in FIG. 1 corresponds to a cross-sectional view that is
taken along the line I-I in FIG. 2. As shown in FIG. 2, the
external shape-defining member 102a has a rectangular planar shape,
for example, and has a square opening at its center. The opening is
a molten metal passing part 102b through which the molten metal is
passed. A shape-defining member 102 is constituted of the external
shape-defining member 102a and the molten metal passing part 102b
as described above.
[0062] The draw-out part 107 has a starter (draw-out member) ST
that is immersed into the molten metal M1, and a lifter PL (not
shown) that drives the starter ST in, for example, vertical
directions.
[0063] As shown in FIG. 1, the molten metal M1 is joined to the
starter ST that is immersed thereinto and then pulled up through
the molten metal passing part 102b following the starter ST with
its contour retained by the surface film or surface tension
thereof. The molten metal that is pulled up from the melt surface
following the starter ST (or the casting M3 that is formed by
solidification of the molten metal M1 that has been drawn out by
the starter ST) by the surface film or surface tension of the
molten metal M1 is herein referred to as "retained molten metal
M2." The interface between the casting M3 and the retained molten
metal M2 is a solidification interface.
[0064] The starter ST is made of ceramic or stainless steel, for
example. The surfaces of the starter ST may be covered with a
protective coating (not shown), such as that of a salt crystal. In
this case, because melt-bonding between the starter ST and the
molten metal M1 can be prevented, the releasability between the
starter ST and the casting M3 can be improved. This makes it
possible to reuse the starter ST. In addition, the starter ST may
have irregular surfaces. In this case, because the protective
coating can be easily deposited (precipitated) on the surfaces of
the starter ST, the releasability between the starter ST and the
casting M3 can be further improved. At the same time, the binding
force in the pull-up direction between the starter ST and the
molten metal M1 during the draw-out of the molten metal can be
improved.
[0065] The supporting rod 103 supports the external shape-defining
member 102a. The supporting rod 103 is coupled to the actuator
105.
[0066] The actuator 105 has a function of moving the external
shape-defining member 102a up and down (in vertical directions) and
in horizontal directions via the supporting rod 103. Thus, the
actuator 105 can move the external shape-defining member 102a
downward when the melt surface level is lowered as the casting
proceeds. In addition, because the actuator 105 can move the
external shape-defining member 102a in horizontal directions, the
longitudinal shape of the casting M3 can be changed freely.
[0067] Each solid heat transfer member 108 is made of a metal that
has high thermal conductivity, such as copper or a copper alloy,
and is placed to contact a surface of the casting M3. More
preferably, each solid heat transfer member 108 is placed to
contact a surface of the casting M3 in the vicinity of the
solidification interface.
[0068] The solid heat transfer members 108 are maintained at a
temperature that is lower than that of the surfaces of the casting
M3 in the vicinity of the solidification interface to cool the
casting M3. By cooling the starter ST and the casting M3 with the
solid heat transfer members 108 while the casting M3 is being
pulled up by the lifter PL (not shown) that has been coupled to the
starter ST, the retained molten metal M2 in the vicinity of the
solidification interface is sequentially solidified and the casting
M3 is formed continuously.
[0069] In the free casting apparatus according to this embodiment,
the casting M3 is cooled not by a cooling medium that is blown out
of a cooling nozzle but by contacting it with the solid heat
transfer members 108. Thus, the free casting apparatus according to
this embodiment can cool the casting M3 quickly without swinging
the retained molten metal M2. This allows the speed at which the
starter ST is pulled up to be increased.
[0070] In addition, the free casting apparatus according to this
embodiment can cool the casting M3 more quickly by contacting the
solid heat transfer members 108 with surfaces of the casting M3 in
the vicinity of the solidification interface. This allows the speed
at which the starter ST is pulled up to be further increased.
[0071] The greater the contact area between the solid heat transfer
members 108 and the casting M3, the higher the cooling rate of the
casting M3. To improve the cooling rate of the casting M3 by
increasing the contact area between the solid heat transfer members
108 and the casting M3, the solid heat transfer members 108 may
have a shape corresponding to the cross-sectional shape of the
casting M3 at a portion of the solid heat transfer member 108
placed into contact with the casting M3, for example. On the other
hand, the smaller the contact area between the solid heat transfer
members 108 and the casting M3, the smaller the friction resistance
therebetween. To reduce the friction resistance between the solid
heat transfer members 108 and the casting M3, the solid heat
transfer members 108 may have a curved surface shape at a portion
of the solid heat transfer member 108 placed into contact with the
casting M3, for example.
[0072] The supporting members 109 are elastic members, such as
springs, which support the solid heat transfer members 108 and bias
the solid heat transfer members 108 into contact with surfaces of
the casting M3. In this embodiment, a case where the supporting
members 109 are springs is described as an example. In this case,
because the solid heat transfer members 108 can be moved in
response to a change in shape of the casting M3, the solid heat
transfer members 108 can be held in contact with the casting M3 and
the friction resistance between the solid heat transfer members 108
and the casting M3 can be reduced. The supporting members 109 are
coupled to the actuator 105 via a supporting rod, for example.
Thus, the solid heat transfer members 108 are movable up and down
(in vertical directions) and in horizontal directions together with
the external shape-defining member 102a.
[0073] Referring to FIG. 1, a free casting method according to this
embodiment is next described.
[0074] First, the starter ST is moved downward and immersed into
the molten metal M1 through the molten metal passing part 102b.
[0075] Then, the starter. ST starts to be pulled up at a prescribed
speed. Here, even after the starter ST is separated from the melt
surface, the molten metal M1 is pulled up (drawn out) from the melt
surface following the starter ST by the surface film or surface
tension thereof and forms a retained molten metal M2. As shown in
FIG. 1, the retained molten metal M2 is formed in the molten metal
passing part 102b. In other words, a shape is imparted to the
retained molten metal M2 by the external shape-defining member
102a.
[0076] Next, the starter ST and the casting M3 are cooled by the
contact with the solid heat transfer members 108. As a result, the
retained molten metal M2 is sequentially solidified from top to
bottom and the casting M3 grows. In this way, the casting M3 can be
cast continuously. It should be noted that the solid heat transfer
members 108 may be moved to the vicinity of the solidification
interface after the position of the solidification interface is
fixed.
[0077] As described above, in the free casting apparatus according
to this embodiment, the casting M3 is cooled not by a cooling
medium that is blown out of a cooling nozzle but by contacting it
with the solid heat transfer members 108. Thus, the free casting
apparatus according to this embodiment can cool the casting M3
quickly without swinging the retained molten metal M2. This allows
the speed at which the starter ST is pulled up to be increased.
[0078] Referring to FIG. 3 and FIG. 4, modifications of the free
casting apparatus according to this embodiment are next
described.
[0079] (First Modification of Free Casting Apparatus According to
Embodiment) FIG. 3 is an enlarged cross-sectional view that
illustrates a first modification of the free casting apparatus that
is shown in FIG. 1. Compared to the free casting apparatus that is
shown in FIG. 1, the free casting apparatus that is shown in FIG. 3
further includes a cooling part 110 through which a cooling medium,
such as water, is circulated in each solid heat transfer member
108. Because the other configurations of the free casting apparatus
that is shown in FIG. 3 are the same as those of the free casting
apparatus that is shown in FIG. 1, their description is
omitted.
[0080] Because the free casting apparatus that is shown in FIG. 3
has a cooling part 110 in each solid heat transfer member 108, the
solid heat transfer members 108 can be maintained at a temperature
that is lower than that of surfaces of the casting M3 in the
vicinity of the solidification interface.
[0081] (Second Modification of Free Casting Apparatus According to
Embodiment) FIG. 4 is an enlarged cross-sectional view that
illustrates a second modification of the free casting apparatus
that is shown in FIG. 1. Compared to the free casting apparatus
that is shown in FIG. 1, the free casting apparatus that is shown
in FIG. 4 further includes cooling nozzles 106 that blow a cooling
medium (such as air, nitrogen, argon or water) onto the upper
surfaces of the solid heat transfer members 108. Because the other
configurations of the free casting apparatus that is shown in FIG.
4 are the same as those of the free casting apparatus that is shown
in FIG. 1, their description is omitted.
[0082] Because the free casting apparatus that is shown in FIG. 4
has cooling nozzles 106 that blow a cooling medium onto the upper
surfaces of the solid heat transfer members 108, the solid heat
transfer members 108 can be maintained at a temperature that is
lower than that of surfaces of the casting M3 in the vicinity of
the solidification interface. The cooling medium that is blown out
of the cooling nozzles 106 is blocked by the solid heat transfer
members 108 and does not reach the retained molten metal M2. Thus,
the retained molten metal M2 can be prevented from being swung.
[0083] The cooling parts 110 that arc shown in FIG. 3 and the
cooling nozzles 106 that are shown in FIG. 4 may be used in
combination. Also, cooling fins may be provided on surfaces of the
solid heat transfer members 108 (especially, on the surfaces onto
which the cooling medium from the cooling nozzles 106 is
blown).
[0084] <Second Embodiment> FIG. 5 is an enlarged
cross-sectional view that illustrates a configuration example of a
free casting apparatus according to a second embodiment. Compared
to the free casting apparatus that is shown in FIG. 1, the free
casting apparatus that is shown in FIG. 5 further includes a metal
wool 111 that is made of a metal that has high thermal
conductivity, such as copper or a copper alloy, as a part of each
solid heat transfer member 108. Because the other configurations of
the free casting apparatus that is shown in FIG. 5 are the same as
those of the free casting apparatus that is shown in FIG. 1, their
description is omitted.
[0085] Because the free casting apparatus according to this
embodiment includes a metal wool 111 as a part of each solid heat
transfer member 108, the solid heat transfer members 108 and the
casting M3 can be held in contact with each other more easily and
the friction resistance between the solid heat transfer member 108
and the casting M3 can be reduced more easily.
[0086] In addition, in the free casting apparatus according to this
embodiment, the contact area between the solid heat transfer
members 108 and the casting M3 can be increased. Thus, the free
casting apparatus according to this embodiment can cool the casting
M3 more quickly. This allows the speed at which the starter ST is
pulled up to be further increased.
[0087] The free casting apparatus according to this embodiment may
further include a cooling part 110 in each solid heat transfer
member 108 as shown in FIG. 6, may further include cooling nozzles
106 that blow a cooling medium onto the upper surfaces of the solid
heat transfer members 108 as shown in FIG. 7, or may include the
cooling parts 110 and the cooling nozzles 106 in combination. The
cooling parts 110 may be routed through the metal wools 111.
Alternatively, a cooling medium may be directly blown onto the
metal wools 111. In these cases, the cooling rate of the casting M3
can be improved.
[0088] <Third Embodiment> FIG. 8 is an enlarged
cross-sectional view that illustrates a configuration example of a
free casting apparatus according to a third embodiment. Compared to
the free casting apparatus that is shown in FIG. 1, the free
casting apparatus that is shown in FIG. 8 includes solid heat
transfer members 108a in place of the solid heat transfer members
108. Because the other configurations of the free casting apparatus
that is shown in FIG. 8 are the same as those of the free casting
apparatus that is shown in FIG. 1, their description is
omitted.
[0089] Each solid heat transfer member 108a has the shape of a
circular column that is rotatable in the direction in which the
casting M3 is pulled up (in a vertical direction). Thus, because
the solid heat transfer members 108a rotate as the casting M3 is
pulled up, the friction resistance between the solid heat transfer
members 108a and the casting M3 can be further reduced.
[0090] The free casting apparatus according to this embodiment may
further include a cooling part 110 in each solid heat transfer
member 108a as shown in FIG. 9, may further include cooling nozzles
106 that blow a cooling medium onto the upper surfaces of the solid
heat transfer members 108a as shown in FIG. 10, or may include the
cooling parts 110 and the cooling nozzles 106 in combination. In
these cases, the cooling rate of the casting M3 can be
improved.
[0091] <Fourth Embodiment> FIG. 11 is an enlarged
cross-sectional view that illustrates a configuration example of a
free casting apparatus according to a fourth embodiment. Compared
to the free casting apparatus that is shown in FIG. 8, the free
casting apparatus that is shown in FIG. 11 further includes a metal
wool 111 that is made of a metal that has high thermal
conductivity, such as copper or a copper alloy, as a part of each
solid heat transfer member 108a. Because the other configurations
of the free casting apparatus that is shown in FIG. 11 are the same
as those of the free casting apparatus that is shown in FIG. 8,
their description is omitted.
[0092] Because the free casting apparatus according to this
embodiment includes a metal wool 111 as a part of each solid heat
transfer member 108a, the solid heat transfer members 108a and the
casting M3 can he held in contact with each other more easily and
the friction resistance between the solid heat transfer member 108a
and the casting M3 can be reduced more easily.
[0093] In addition, in the free casting apparatus according to this
embodiment, the contact area between the solid heat transfer
members 108a and the casting M3 can be increased. Thus, the free
casting apparatus according to this embodiment can cool the casting
M3 more quickly. This allows the speed at which the starter ST is
pulled up to be further increased.
[0094] The free casting apparatus according to this embodiment may
further include a cooling part 110 in each solid heat transfer
member 108a as shown in FIG. 12, may further include cooling
nozzles 106 that blow a cooling medium onto the upper surfaces of
the solid heat transfer members 108a as shown in FIG. 13, or may
include the cooling parts 110 and the cooling nozzles 106 in
combination. The cooling parts 110 may be routed through the metal
wools 111. Alternatively, a cooling medium may be directly blown
onto the metal wools 111. In these cases, the cooling rate of the
casting M3 can be improved.
[0095] <Fifth Embodiment> FIG. 14 is an enlarged
cross-sectional view that illustrates a configuration example of a
free casting apparatus according to a fifth embodiment. Compared to
the free casting apparatus that is shown in FIG. 8, the free
casting apparatus that is shown in FIG. 14 includes supporting
members 109a in place of the supporting members 109, which are
elastic members, such as springs.
[0096] Each supporting member 109a supports a solid heat transfer
member 108a in a suspended fashion. Each solid heat transfer member
108a is held in contact with a surface of the casting M3 by its own
weight. In other words, the supporting members 109a bias the solid
heat transfer member 108a into contact with a surface of the
casting M3.
[0097] FIG. 15 is a cross-sectional view that is taken along the
line II-II in FIG. 14. As shown in FIG. 15, a cooling part 110
through which a cooling medium W1, such as water, is circulated is
provided in each solid heat transfer member 108a.
[0098] FIG. 16 is an enlarged cross-sectional view of the cooling
part 110 that is shown in FIG. 14. As shown in FIG. 16, the cooling
part 110 has buckets 112, for example, that scoop up the cooling
medium W1 as the solid heat transfer member 108a rotate. In this
case, because the cooling medium W1 can be scooped up (lifted up)
to the location where the solid heat transfer member 108a contacts
the casting M3 even when the amount of the cooling medium W1 is
small (the surface level of the cooling water is low), the cooling
rate of the casting M3 can be improved. In addition, the buckets
112 can also function as cooling fins.
[0099] As described above, in the free casting apparatuses
according to the first to fifth embodiments, the casting M3 is
cooled not by a cooling medium that is blown out of a cooling
nozzle but by contacting it with the solid heat transfer members
108 (108a). Thus, the free casting apparatus according to the first
to fifth embodiments can cool the casting M3 quickly without
swinging the retained molten metal M2. This allows the speed at
which the starter ST is pulled up to he increased.
[0100] While a case where a casting with the shape of a rectangular
column (rectangular column-shaped casting) is cast is described as
an example in the above embodiments, the present invention is not
limited thereto. The present invention is also applicable in
producing a casting with another shape, such as the shape of a
rectangular tube, circular column or circular tube. A case where a
casting with the shape of a rectangular tube is cast is briefly
described below with reference to FIG. 17 and FIG. 18.
[0101] FIG. 17 is a cross-sectional view that illustrates another
configuration example of a free casting apparatus according to the
present invention. The free casting apparatus that is shown in FIG.
17 includes an internal shape-defining member 102c in addition to
the external shape-defining member 102a.
[0102] The internal shape-defining member 102c defines the internal
shape of the casting M3 to be cast, and the external shape-defining
member 102a defines the external shape of the casting M3 to be
cast. The casting M3 that is shown in FIG. 17 is a tubular hollow
casting (in other words, a pipe) that has a tubular shape in its
horizontal cross-section (which is hereinafter referred to as
"transverse cross-section"). More specifically, the internal
shape-defining member 102c defines the internal shape of the
transverse cross-section of the casting M3, and the external
shape-defining member 102a defines the external shape of the
transverse cross-section of the casting M3.
[0103] FIG. 18 is a plan view of the internal shape-defining member
102c and the external shape-defining member 102a. The
cross-sectional view of the internal shape-defining member 102c and
the external shape-defining member 102a in FIG. 17 corresponds to a
cross-sectional view that is taken along the line III-III in FIG.
18. As shown in FIG. 18, the external shape-defining member 102a
has a rectangular planar shape, for example, and has a square
opening at its center. The internal shape-defining member 102c has
a rectangular planar shape, and is located at the center of the
opening of the external shape-defining member 102a. The gap between
the internal shape-defining member 102c and the external
shape-defining member 102a defines a molten metal passing part 102b
through which the molten metal is passed. A shape-defining member
102 is constituted of the internal shape-defining member 102c, the
external shape-defining member 102a, and the molten metal passing
part 102b as described above. With this configuration, a casting
with the shape of a rectangular tube can be cast.
[0104] The present invention is not limited to the above
embodiments, and may be modified as needed without departing from
its scope. For example, the above-mentioned configuration examples
may be used in combination.
* * * * *