U.S. patent number 3,710,843 [Application Number 05/099,809] was granted by the patent office on 1973-01-16 for method for altering the cross-sections of continuously cast metal pieces.
This patent grant is currently assigned to Nippon Steel Corporation. Invention is credited to Toyosaburo Hamano, Shinsuke Hashimoto, Takeshi Hiromoto, Tadashi Murakami, Shingo Shibamoto, Zenzo Soejima.
United States Patent |
3,710,843 |
Murakami , et al. |
January 16, 1973 |
METHOD FOR ALTERING THE CROSS-SECTIONS OF CONTINUOUSLY CAST METAL
PIECES
Abstract
A method and a casting water cooled mold for altering the width
dimension of a continuously cast metal piece during a continuous
casting operation without the need of replacing the mold with
different molds for producing cast pieces of different dimensions.
The mold for carrying out the method has two water-cooled front
walls and two water-cooled side walls, each of which walls are
press-fixable and releasable to and from each other and all but one
of the front walls being formed by two sections, said sections
being movable in a horizontal direction and vertically
press-fixable to each other.
Inventors: |
Murakami; Tadashi (Himeji,
JA), Hiromoto; Takeshi (Himeji, JA),
Soejima; Zenzo (Himeji, JA), Hamano; Toyosaburo
(Takasago, JA), Hashimoto; Shinsuke (Himeji,
JA), Shibamoto; Shingo (Himeji, JA) |
Assignee: |
Nippon Steel Corporation
(Tokyo, JA)
|
Family
ID: |
22276725 |
Appl.
No.: |
05/099,809 |
Filed: |
December 21, 1970 |
Current U.S.
Class: |
164/491 |
Current CPC
Class: |
B22D
11/05 (20130101) |
Current International
Class: |
B22D
11/05 (20060101); B22d 011/00 () |
Field of
Search: |
;164/82,273,280,281,283 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Annear; R. Spencer
Claims
We claim:
1. A method of altering the width dimension of a continuously cast
piece in the continuous production of the cast piece by continuous
casting by pouring a molten metal into a water-cooled casting mold
composed of a water-cooled front wall and water-cooled side walls,
each of said walls being formed by two sections, said sections
being one above the other forming upper and lower stages of the
mold, while vertically vibrating said mold, and pulling the
finished casting out of the bottom of the mold, said method
comprising the steps of altering the distance between the two upper
sections of the respective side walls to a distance less than the
distance between the two lower sections of the respective side
walls while producing the cast piece in the lower stage of the
mold, suspending the pulling out of the cast piece, then elevating
the pouring level of the molten metal up to near the top of the
upper state of the mold, resuming the pulling-out of the cast piece
after the molten metal in the upper stage of the mold has formed a
shell on the outer periphery thereof, altering the distance between
the two lower sections to bring them into correspondence with the
upper sections after the portion of the cast piece formed in the
lower stage of the mold has cleared the mold, and stopping the
vibrating of the mold at the latest just before suspending the
pulling out of the cast piece and starting the vibrating of the
mold when portions of the cast piece which might be damaged are
free of the mold.
2. The method as claimed in claim 1 in which the two upper sections
of the side walls are horizontally moved equal distances toward
each other to make the distance between them different from that
between the corresponding two lower sections of the respective side
walls to obtain the desired width in the upper stage of the
mold.
3. The method as claimed in claim 1 in which the two upper sections
of the side walls are horizontally moved different distances toward
each other to make the distance between them different from that
between the corresponding two lower sections of the respective side
walls to obtain the desired width in the upper stage of the
mold.
4. The method as claimed in claim 1 in which only one of the two
upper sections of the side walls is horizontally moved to make the
distance between the upper sections of the side walls different
from that between the corresponding two lower sections of the
respective side walls to obtain the desired width in the upper
stage of the mold.
5. The method as claimed in claim 1 wherein the water-cooled front
wall has upper and lower sections, further comprising the steps of,
prior to moving the sections of the side walls, releasing the
water-cooled front wall from horizontally press-fixing the
water-cooled side walls to a fixed front wall, and releasing the
press-fixing of the upper and lower sections of the said
water-cooled front wall and then again press-fixing the upper and
lower sections of the water-cooled front wall and the side walls to
each other and press-fixing the water-cooled side walls the
water-cooled front wall and the fixed front wall, after the
water-cooled side walls have been moved in a desired amount.
6. The method as claimed in claim 1 wherein the vertical vibrating
of the water-cooled casting mold is resumed at the moment when the
gap formed between the stepped part of the cast piece between the
larger dimension between the lower side wall sections and the
smaller dimension between the upper side wall sections, and the
under surface of the upper sections of the respective side walls
becomes larger than the magnitude of the vertical vibration of the
casting mold.
7. A method of altering the width dimension of a continuously cast
piece in the continuous production of the cast piece by continuous
casting by pouring a molten metal into a water-cooled casting mold
composed of a water-cooled front wall and water-cooled side walls,
each of said walls being formed by two sections, said sections
being one above the other forming upper and lower stages of the
mold, while vertically vibrating said mold, and pulling the
finished casting out of the bottom of the mold, said method
comprising the steps of altering the distance between the two upper
sections of the respective side walls to a distance greater than
the distance between the two lower sections of the respective side
walls, while producing the cast piece in the lower stage of the
mold, suspending the pulling out of the cast piece, then elevating
the pouring level of the molten metal up to near the top of the
upper stage of the mold, altering the distance between the two
lower sections to bring them into correspondence with the upper
sections, resuming the pulling-out of the cast piece having the
altered dimension after the molten metal in the upper stage of the
mold has formed a shell on the outer periphery thereof, and
stopping the vibrating of the mold at the latest just before
suspending the pulling-out of the cast piece and starting the
vibrating of the mold when portions of the cast piece which might
be damaged are free of the mold.
8. The method as claimed in claim 7 in which the two upper sections
of the side walls are horizontally moved equal distances away from
each other to make the distance between them different from that
between the corresponding two lower sections of the respective side
walls to obtain the desired width in the upper stage of the
mold.
9. The method as claimed in claim 7 in which the two upper sections
of the side walls are horizontally moved different distances away
from each other to make the distance between them different from
that between the corresponding two lower sections of the respective
side walls to obtain the desired width in the upper stage of the
mold.
10. The method as claimed in claim 7 in which only one of the two
upper sections of the side walls is horizontally moved to make the
distance between the upper sections of the side walls different
from that between the corresponding two lower sections of the
respective side walls to obtain the desired width in the upper
stage of the mold.
11. The method as claimed in claim 7 wherein the water-cooled front
wall has upper and lower sections, further comprising the steps of,
prior to moving the sections of the side walls, releasing the
water-cooled front wall from horizontally press-fixing the
water-cooled side walls to a fixed front wall, and releasing the
press-fixing of the upper and lower sections of the said
water-cooled front wall and then again press-fixing the upper and
lower sections of the water-cooled front wall and the side walls to
each other and press-fixing the water-cooled side walls between the
water cooled front wall and the fixed front wall, after the
water-cooled side walls have been moved in a desired amount.
12. The method as claimed in claim 7 wherein the vertical vibrating
of the water-cooled casting mold is resumed after the molten metal
between the upper side wall sections coagulates sufficiently to
withstand pulling-out at the stepped part of the cast piece between
the larger dimension between the upper side wall sections and the
larger dimension between the loser side wall sections and the lower
side wall sections are brought into coincidence with the upper side
wall sections.
Description
The present invention relates to a method for altering the
cross-sections and particularly the width dimensions of cast pieces
without replacing the mold during the continuous casting of a
molten metal.
The continuous casting of molten metals as a means of manufacturing
such crudely shaped materials as slabs, billets and blooms is much
superior to conventional blooming methods both with respect to the
equipment and productivity and is therefore has been extensively
adopted.
Recently, as is generally known, in the field of casting steels
serious studies are also being carried out and efforts are being
exerted in practicing the results of the studies with great
effect.
The principle of continuous casting of such molten metal as molten
steel and the like is that the molten metal is continuously fed
into a bottomless water-cooled mold, in which a dummy bar is
positioned, and cast pieces are continuously pulled out of the
bottom part of the water-cooled mold, while the molten metal is
cooled, at a velocity corresponding to the molten metal pouring
velocity.
In carrying out a continuous casting method, it is necessary to
produce cast pieces with cross-sectional dimensions which are
optimum for the cross-sectional dimensions of the products to be
produced from the cast pieces in order to obtain cast pieces which
can be easily worked and produce a high yield in the processing
step, such as rolling, subsequent to the continuous casting step
for producing the products. However, it has not been possible to
alter the cross-section of the cast piece for a product to be
finally produced while still using the same mold during the
continuous casting. Consequently, usually in continuous casting the
mold must be rearranged or modified to the desired cross-section or
replaced by a prepared mold of other desired dimensions so that the
cross-section of the cast piece to be produced can be altered. As a
result thereof, continuous casting must be interrupted for a long
time, because it takes, for instance, at least 1 hour to rearrange
or modify the mold or to replace the same.
In a conventional continuous casting operation it is customary to
use a water-cooled mold of fixed dimensions having an integral wall
body. A few proposals have been made for using a water-cooled
continuous casting mold having walls divided into several sections.
However, the arrangement of mold walls in several sections is for
the purpose of increasing the cooling effect, to improve the
quality of cast pieces or to make the production of cast pieces of
large size possible, as is disclosed, for instance, in the Japanese
patents published in the Patent Office Bulletins Nos. 1461/1954 and
12301/1963.
The present invention has as its object to provide a method for
continuously altering the cross-sections and particularly the width
dimensions of cast pieces during the casting, in a manner which
heretofore has not been possible in a continuous casting
method.
More concretely, the present invention has as its object to provide
a method which employs a continuous casting water-cooled mold,
which is able to be taken into pieces, or in other words, a
water-cooled mold constructed by a water-cooled front wall and
water-cooled side walls, each of which walls is formed by two
sections movable independently of each other.
The terms used in the disclosure of the present invention
"water-cooled front wall" and "wall-cooled side wall" are to be
understood as follows: the former designates a mold wall having a
surface forming the front or back surface of a cast piece to be
produced and the latter designates a mold wall having a surface
forming each side surface of the above-mentioned cast piece.
Thus, the present invention has several novel features, as will be
described hereinafter:
The primary feature of the present invention is to provide a method
which utilizes a mold constructed by positioning respective
water-cooled side walls on both the right and left sides between
two water-cooled front walls, each of the side walls and one of the
front walls having two sections, which are positioned one over the
other, forming upper and lower stages, the remaining water-cooled
front wall being an integral body.
A second feature of the present invention is to provide a method
which utilizes a water-cooled mold, wherein a water-cooled front
wall and two water-cooled side walls are formed by upper and lower
sections each of said sections of each wall being movable
horizontally independent of the other.
The horizontal movement of each wall section of the water-cooled
front wall is in the thickness direction of a cast piece to be
made. This is for the purpose of enabling the water-cooled side
walls, or more exactly, the side wall sections to move horizontally
as will be explained later. The water-cooled front wall which is
not divided into two sections, can not move, but is fixed.
The horizontal movement of the water-cooled side wall sections is
in the width direction of the casting being made. It is for the
purpose of altering the width dimension of the above-mentioned
casting.
The third feature of the present invention is to provide a method
which utilizes a mold having a water-cooled front wall and
water-cooled side walls, each of which has upper and lower sections
horizontally movable independently of the other, wherein the upper
and lower sections of each of the water-cooled front wall and the
water-cooled side walls pressed tightly together so that they are
fixed to each other respectively. This condition will hereinafter
be referred to as "press fixing", or being "press-fixed."
In the case of the water-cooled front wall the press-fixing can be
of two kinds: that is, one is where the upper and lower sections of
the water-cooled front wall itself are vertically press-fixed to
each other and the other is where the water-cooled side walls lying
between two water-cooled front walls, that is, the fixed front wall
and the water-cooled front wall formed by two sections are
press-fixed to the fixed water-cooled front wall by the horizontal
pressure of the other front wall formed by two sections.
In the case of the water-cooled side walls the press-fixing is the
state wherein the upper and lower sections of each of the
water-cooled side walls are vertically press-fixed to each
other.
The fourth feature of the present invention is to provide a method
which utilizes a mold having a water-cooled front wall and
water-cooled side walls, each of which walls are formed by two
sections horizontally movable independently of the other and
press-fixable, wherein the respective upper and lower sections of
the water-cooled side walls are L-shaped.
By using the L-shaped water-cooled side wall sections the width
dimensions of cast pieces can be altered over a wider range, as
will be later explained, because the contact surface between the
upper and lower sections of the water-cooled side wall can be made
large.
The fifth feature of the present invention is to provide a method
of obtaining cast pieces of required dimensions, as the occasion
demands, by altering the positions of the water-cooled side wall
sections during the continuous casting of a molten metal by using
the above-mentioned mold having the water-cooled front wall and
water-cooled side walls, each of which walls are formed by the
upper and lower sections horizontally movable independently of the
other and which are press-fixable.
In the following the substance of the present invention will be
explained in greater detail with reference to the attached drawings
so that it can be more clearly understood.
In the attached drawings:
FIG. 1 is an exploded perspective view of a continuous casting
water-cooled mold according to the present invention.
FIG. 2 is an explanatory view showing a mechanism for supporting
and fixing the continuous casting water-cooled mold and a mechanism
for press-fixing the said mold.
FIG. 3 is an explanatory view, partially in cross-section showing a
press-fixing mechanism for the water-cooled front wall for
horizontally press-fixing the water-cooled side walls.
FIG. 4 is an explanatory view showing a cotter driving mechanism
for operating the press-fixing mechanism of the water-cooled front
wall shown in FIG. 3.
FIG. 5 is an explanatory view showing a mechanism for supporting
and fixing the water-cooled side walls and vertically press-fixing
the said water-cooled side wall sections with respect to each
other.
FIG. 6 is a sectional explanatory view showing a mechanism for
horizontally moving the water-cooled side wall sections.
FIG. 7 is a magnified explanatory view of the part A in FIG. 2.
FIG. 8 is a vertical sectional explanatory view showing the cooling
structure of the water-cooled side wall section.
FIG. 9 is a sectional explanatory view taken on line B--B in FIG.
8.
FIGS. 10 and 11 are sectional views taken on line C--C in FIG. 9
showing a modification of the cooling water circulating system.
FIG. 12 is a block diagram of a control circuit, showing
schematically the continuous casting according to the present
invention.
FIGS. 13a-13e are explanatory views showing the steps of altering
the cross-section of a cast piece to a smaller size; and
FIGS. 14a.sub.1 - 14e.sub. 1 are explanatory views showing the
steps of altering the cross-section of a cast piece to a larger
size.
In FIG. 1 the mold 1 comprises a first water-cooled side wall
having two sections 6 and 7, which are positioned one over the
other, forming upper and lower portions, and another water-cooled
side wall also formed by upper and lower sections 6' and 7'. These
side walls are positioned opposite each other between a fixed
water-cooled front wall 2 formed in one piece and a water-cooled
front wall opposed thereto and formed by upper and lower sections 3
and 4, which are positioned one over the other. The fixed
water-cooled front wall 2 can have the same construction as the
water-cooled front wall formed by the upper and lower sections 3
and 4.
The mold of the present invention having the construction as
described above is used during the continuous casting operation
with the above-mentioned four walls being pressed tightly against
and fixed to each other and with the upper and lower sections of
each wall being vertically press-fixed to each other. When it is
required to alter the width dimension of a cast piece, the space
between the water-cooled side wall sections 6 and 6' and 7 and 7'
must be altered, that is, widened or narrowed (see FIGS. 13 and
14). For this purpose they must be, of course, at first released
from the front walls.
The mechanisms for press-fixing the water-cooled front walls and
side walls and their sections to each other and for releasing them
from each other will be described hereinafter.
The fixed water-cooled front wall 2 is fixed to a fixing device 8
by means of a supporting arm 9, as shown in FIG. 2. This
water-cooled front wall 2 determines the location of the center of
a cast piece E passing between pull-off rolls (see FIG. 12) used to
pull the cast piece out of the mold 1.
The water-cooled front wall sections 3 and 4 can move forwardly and
backwardly independently of each other and are connected to a
press-fixing mechanism 10 for the side wall sections 3 and 4 for
press-fixing the water-cooled side walls.
FIG. 3 shows an example of the press-fixing mechanism 10 for one of
the water-cooled front wall sections 3 and 4.
In the drawing, 13 is a frame of the press-fixing mechanism 10.
Within said frame there are provided four hollow shafts 14 for
supporting the water-cooled front wall section 3, upper and lower
pairs with corresponding shafts in the upper and lower pairs being
vertically aligned. The hollow shafts themselves are supported by
means of bearings 15 and 16 in frame 13.
The water-cooled front wall section 3 is supported on the ends of
the above-mentioned hollow shafts by means of a notched part 17 at
the end of each of said hollow shafts held between supporting metal
pieces 18 provided on the water-cooled front wall section 3.
In the middle part of each of the outer periphery of the
above-mentioned hollow shafts a threaded portion 19 is provided
extending along the length of said hollow shaft a distance
sufficient to move the shaft rightwards and leftwards a desired
distance, and meshing with the said screw is an interiorly threaded
portion 20 of a worm wheel 21. Said worm wheel 21 is rotatably
supported at a fixed position by the above-mentioned bearings 15
and 16.
The worm wheel 21 is engaged with a worm 23 on a rotary shaft 22 on
the frame 13. Said rotary shaft 22 can be rotated manually with a
handle (not illustrated) or can be rotated by using a motor (not
illustrated).
A shaft 25 is slidably positioned in the interior of each hollow
shaft 14 and the shaft 25 is provided with a plate spring 26 at the
front end thereof. The front end surface of said plate spring 26 is
in contact with a metal piece 27 on the back of the water-cooled
front wall section 3. At the rear end of the above-mentioned shaft
25 there is mounted a cotter 28 vertically movable through slots in
the rear ends of shafts 14 and for pushing the shafts 25
forwards.
Frames 13 having the equipment as above described are provided for
both the upper and lower wall sections 3 and 4 and together they
constitute the press-fixing mechanism 10.
In press-fixing the water-cooled side wall sections 6 and 6' and 7
and 7' between the fixed water-cooled front wall 2 and the
water-cooled front wall formed by sections 3 and 4 by pushing the
water-cooled front wall formed by sections 3 and 4 towards the
fixed water-cooled front wall 2, the above-mentioned cotter 28 for
pushing the shafts 25 is an important element. The cotter 28 is
driven vertically by a driving mechanism shown in FIG. 4.
FIG. 4 is a general view of a cotter driving mechanism for pushing
the rear ends of the respective shafts 25 of the water-cooled front
wall sections 3 and 4 forwards, wherein 29 and 30 are arms, which
are rotatably mounted on the frame 13 on shafts 31 and 32.
Each of the above-mentioned arms 29 and 30 is provided with a hole
33, through which extends a metal piece 34 projecting from the
cotter 28. The above-mentioned arms 29 and 30 are rotatably
connected with each other at one end by an arm 35.
The other end of the arm 30 is pivotally connected with a rod 37 of
a piston-cylinder mechanism 36 mounted on the frame 13.
When operating the thus constructed press-fixing mechanism 10 to
assemble the water-cooled mold walls, the rotary shaft 22 in the
mechanism 10 shafts 14 through worm gears 23 and 21, whereby the
surfaces of the water-cooled front wall sections 3 and 4 and the
water-cooled side wall sections 6 and 7 and 6' and 7' are brought
into contact with each other and with the surface of the fixed
front wall 2 such that the wall sections 6 and 6' and 7 and 7' can
be moved by a sliding device 38, which will be described
hereinafter. At this point rotation of the rotary shafts 22 is
stopped.
Then, in order to press and fix all the mold walls to each other,
the shafts 25 must be pushed in the forward direction. For this
purpose the cotters 28 are moved by the operation of the arms 29
and 30 by driving the piston-cylinder mechanisms 36, whereby the
shafts 25 are pushed in the forward direction and the water-cooled
front wall parts 3 and 4 are pushed by the plate spring 26 so that
the water-cooled side wall parts 6 and 6' and 7 and 7' are pressed
against and fixed to the water-cooled front wall 2.
On the contrary, when the water-cooled side wall sections 6 and 6'
are to be moved to alter the distance between them, the
press-fixing action of the water-cooled front wall sections 3 and 4
must be eliminated by releasing the water-cooled wall sections 3
and 4 from pressing action of the shafts 25. This is done by
driving the cotters 28 in the opposite direction.
Further, when disassembling the mold for the purpose of repair of
the mold, the cotters 28 are operated to release the shafts 25 and
thereafter the rotary shafts 22 are caused to rotate in the
direction opposite to the above-mentioned direction. Then, the
hollow shafts 14 are caused to withdraw to a determined position
through the worm gears 23 and 21.
In the foregoing description there has been described the manner in
which two water-cooled side walls are pressed and fixed between the
fixed water-cooled front wall 2 and the water-cooled front wall
formed by the sections 3 and 4 by advancing the hollow shafts 14
and the shafts 25. However, it is also possible to use a piston and
cylinder instead of the hollow shafts 14 and the shafts 25.
Further, an eccentric cam can be used instead of the cotter 28 for
pushing each of the shafts 25.
The horizontal movement of the water-cooled side wall sections is
carried out by means of the sliding devices 38, on which the
water-cooled side wall sections 6 and 7 are supported and fixed by
arms 39, as is shown in FIG. 5.
As shown in FIG. 6, the abovementioned sliding devices 38 rotate
threaded shafts 41 through speed change gears 40 consisting of worm
gears by the rotation of a motor (not illustrated), whereby the
arms 39 meshing with said threaded shafts are advanced and
withdrawn in the horizontal direction. 42 is a sliding surface
supporting the arm 39 and bearings 43 are provided to support
threaded shaft 41.
In order to be able to move the water-cooled side wall sections 6
and 6' or 7 and 7' horizontally in opposite directions by using the
above-mentioned sliding device 38, it is, of course, necessary to
release the water-cooled side wall sections 6 and 6' or 7 and 7' by
operating the press-fixing device 10.
When the horizontal movement of the water-cooled side wall sections
6 and 6' or 7 and 7' is finished, however, it is important to
press-fix them again by pressing the water-cooled front wall
sections 3 or 4 toward the fixed wall 2.
Next, a mechanism for fixing the water-cooled front wall sections 3
and 4 to each other and water-cooled side wall sections 6 and 7 and
6' and 7' to each other will be described.
In order to fix the water-cooled front wall sections 3 and 4 to
each other, it is necessary at first to support the lower section
4. For this purpose projections 44 are provided on both the lower
parts of both ends of the water-cooled wall 2 and the section 4,
and a hole 44' is provided in each projection 44. A bar member 45
is passed through said holes 44' and 44' and is fixed at the ends
thereof to the fixing device 8 and the press-fixing mechanism 10
respectively, as shown in FIGS. 1, 2 and 5.
On the other hand, a projection 46 is provided on the lower part of
each end of the water-cooled front wall section 3.
Further, a bar member 47 is rotatably pivoted at one end on a pin
48 on the mold side of the press-fixing mechanism 10, and is
positioned on the above-mentioned projection 46. At the other end
the bar member 47 is engaged with a fixed metal piece 49 provided
on the fixing device 8.
As shown in FIG. 7, a tapered cotter 50 is inserted between said
fixed metal piece 49 and bar member 47 so as to push the bar member
47 downwards and push down the projection 46.
Thus, the water-cooled front wall sections 3 and 4 are vertically
press-fixed by means of the bar member 47 in collaboration with the
bar member 45.
The advance and retreat of the above-mentioned cotter 50 is
accomplished by means of a piston cylinder mechanism 51, as is
shown in FIG. 7. Alternatively, a driving mechanism (not
illustrated) consisting of a screw and gear may be adopted instead
of the piston cylinder mechanism 51.
The devices for fixing the water-cooled front sections 3 and 4 to
each other are provided on both right and left end parts of the
water-cooled front wall sections 3 and 4.
Devices for fixing the water-cooled side wall sections 6 and 7 and
6' and 7' to each other will be described with reference to FIGS.
1, 2 and 5.
Supporting metal pieces 52 and 53 are securely mounted on the
water-cooled side wall sections 6 and 6' and 7 and 7' respectively.
The lower end of the supporting metal piece 53 for each of said
water-cooled side wall sections 7 and 7' is in contact with the
above-mentioned bar member 45.
Further, a bar member 54 is rotatably pivoted at one end on a pin
55 on the mold side of the fixing device 8, engages the supporting
metal piece 52 of the water-cooled side wall sections 6 and 6', and
is engaged at the other end with a fixed metal piece 56 provided on
the press-fixing mechanism 10. By inserting a cotter 50' provided
with a taper, like the cotter described in connection with FIG. 7,
between said fixing metal piece 56 and bar member 54, the bar
member 54 can be pushed downwards and the supporting metal piece 52
is pushed down. Thus, the water-cooled side wall sections 6 and 6'
and 7 and 7' are vertically press-fixed to each other respectively
by means of the bar member 54 in collaboration with the bar member
45.
As, in the present invention cast pieces are produced by using the
continuous casting mold, wherein the above-mentioned water-cooled
front wall sections 3 and 4 and water-cooled side wall sections 6
and 7 and 6' and 7' are respectively vertically press-fixed by
means of the press fixing devices, by an ordinary continuous
casting method comprising continuously feeding a fixed amount of
molten metal, for instance, molten steel, while vertically
vibrating the mold up and down.
In the foregoing there has been described the use of the cotters 50
and 50' as a means of pushing down the bar members 47 and 54 by
inserting them, when press-fixing the water-cooled front wall
sections 3 and 4 and water-cooled side wall sections 6 and 7 and 6'
and 7' between the bar members 47 and 54 and the fixed metal pieces
49 and 56 respectively. However, it is also possible to replace the
fix metal pieces 49 and 56 by piston cylinder mechanisms or
eccentric cams (not illustrated) so that the bar members 47 and 54
may be directly pushed down thereby to vertically press-fix the
water-cooled front wall sections 3 and 4 and water-cooled side wall
sections 6 and 7 and 6' and 7' respectively.
Further, the water-cooled front wall sections 3 and 4 and
water-cooled side wall sections 6 and 7 and 6' and 7' may be
vertically press-fixed directly by means of a cotter or an
eccentric cam respectively by inserting the cotter or positioning
the eccentric cam between the projections provided on the
water-cooled front wall sections 3 and 4 or water-cooled side wall
sections 6 and 6' or 7 and 7' and projections (not illustrated)
corresponding to the above-mentioned fixed metal pieces, on the
press-fixing mechanism 10 for the water-cooled front wall sections
3 and 4 or on the sliding device 38 for the water-cooled side wall
sections 6 and 6' or 7 and 7' on the side of the mold.
In the mold of the present invention, that is, in the mold composed
of the water-cooled front wall and water-cooled side walls having
two sections respectively, which sections are positioned one above
the other, forming the upper and lower stages, and separately
movable in the horizontal direction and capable of being
press-fixed to each other, it is preferable to shape each of the
water-cooled side wall sections 6 and 6' and 7 and 7' in the form
of an L. Making the respective water-cooled side wall sections 6
and 6' and 7 and 7' L-shaped makes it possible to move the wall
sections 6 and 6' relative to the wall sections 7 and 7' to a large
extent, whereby the object of the present invention can be
advantageously achieved, as will be later described.
FIG. 1 shows the embodiment, in which the above-mentioned L-shaped
water-cooled side walls are used. As shown in FIG. 8 each of the
water-cooled side wall sections, for instance, sections 6 and 6',
consists of a side surface 57 and a sliding surface 58. As regards
the cooling system for each of the L-shaped side wall sections it
is preferable to provide the side surface and sliding surface with
separate cooling systems respectively, as shown in FIGS. 8 and 9.
In the cooling system for the side surface 57 there are provided
water feeding and discharging ports 59 and 60 on the back side of
the surface 57 and a plurality of rows of flow paths running
parallel with the side surface 57 and communicating with said ports
59 and 60.
The port 60 for the water discharge is provided with a water
discharging jacket 62 and the port 59 for the water feed is
provided with a water feeding jacket 63. 64 is a water supply pipe
and 65 is a water discharging pipe.
On the other hand, the cooling system for the sliding surface 58
has water feed and discharge ports 67 and 68 on the end surface 66
of the sliding surface 58 and is provided with a plurality of side
by side flow paths running parallel with the sliding surface 58, as
shown in FIGS. 10 and 11.
The ports 68 for the water discharge are provided with water
discharging jackets 70 and the ports 67 for the water feed are
provided with water feeding jackets 71. The arrangement of the
inlets and outlets of the above-mentioned flow paths can be in the
order of the inlet side -- outlet side -- outlet side -- inlet
side, as shown in FIG. 10 or the flow paths can be concentrically
arranged so that a plurality of inlets are connected to a single
feeding jacket and a plurality of outlets are connected to a single
discharging jacket, as shown in FIG. 11. In the drawings, 72 is a
water feed pipe and 73 is a water discharge pipe.
With the cooling systems arranged as described the cooling capacity
of the boundry part of the side surface 57 and the sliding surface
58 can be greatly increased.
Now, the operation of the continuous casting according to the
method of the present invention and using the described apparatus
will be explained with reference to FIG. 12. First of all, the
water-cooled front wall 2 and each of the front wall sections 3 and
4 and the water-cooled side wall sections 6 and 6' and 7 and 7'
from which the mold 1 is constructed, must have sufficient cooling
capacity for performing an ordinary continuous casting. The
water-cooled mold 1 is so compactly constructed that all wall
sections may be jointly vertically vibrated in the conventional
manner, and the water-cooled side wall sections 6 and 6' and 7 and
7' are so arranged that they may be separately moved independently
of each other in the width direction of a cast piece E, as
described hereinbefore.
On the side of the water-cooled mold 1 there is provided a
radioactive ray position detecting device 77 to detect the level of
a molten steel D poured-in through a pouring pipe 75 of a tundish
74, and a position detecting measuring signal from the said
position detecting device 77 is impressed on a control device
78.
A stopper operating device 79 driven by an instruction from the
said control device 78 moves a stopper 80 vertically to control the
volume of the molten steel D poured into the mold.
The molten steel D poured into the water-cooled mold 1 through the
pouring pipe 75 is cooled in the water-cooled mold 1 and is pulled
as a cast piece E out of the bottom part of said water-cooled mold
1. To control the velocity with which the cast piece E is pulled
out, the rotating velocity of the pull-out roll or guide roll 81 is
detected by a pulse transmitter 82. Said pull-out velocity signal
is impressed on the controlling device 78. 83 is a driving device
for the pull-out roll or guide roll 81. Said driving device 83 is
controlled by the control device 78. 84 is a device for lifting of
the tundish 74.
On the basis of the cooling capacity of the water-cooled mold 1,
the driving device 83 is operated at an appropriate velocity by the
instruction from the control device 78 and the cast piece E is
pulled out. At the same time, the stopper operating device 79
operates to control the volume of flow of the molten steel in
response to the pull-out velocity of the cast piece E and the
molten steel D is poured into the water-cooled mold 1 through the
pouring pipe 25. The cast piece E cooled in the water-cooled mold 1
is pulled out at a controlled velocity.
During such continuous casting, the width dimension of the cast
piece can be altered by the steps shown in FIGS. 13 or 14. FIGS.
13a to 13e show steps of altering the cross-section of the cast
piece E from a fixed width dimension to a smaller width dimension.
First of all, the configuration of the mold set for continuous
casting as shown in FIG. 13a is changed to reduce the width
dimension by changing the positions of the water-cooled side wall
sections 6 and 6' in the upper stage, as shown in FIG. 13 (b). The
horizontal movements of the side wall sections 6 and 6' for
changing the distance between them to that shown in FIG. 13b are
performed by carrying out steps as follows:
At first, the press-fixed condition of the sections 6 and 7 and 6'
and 7' is released by releasing the bar member 54 engaging the
above-mentioned sections by withdrawing the cotter 50'. Then, the
press-fixed condition of the front wall sections 3 and 4 is
released by releasing the bar member 47 from engagement with the
said sections by withdrawing the cotter 50. Thereafter, the
press-fixed condition of the side wall sections 6 and 7 and 6' and
7' and the front wall sections 3 and 4 is to be removed by
withdrawing the shaft 25 by appropriately moving the cotter 25.
With the mold parts in the thus released state the sliding device
38 can operate to horizontally move the sections 6 and 6' in the
direction toward each other, to the positions as shown in FIG. 13b.
Then, the vertical vibrating movement of the water-cooled mold 1 is
stopped and the pull-out of the cast piece E is stopped. Then, as
shown in FIG. 13c, the amount of the molten steel D poured-in is
increased by increasing the opening of the stopper 80 until the
pouring level 76 along the water-cooled side walls 6 and 6' is
reached. At the same time, the tundish 74 is elevated in response
to the change in the molten steel level in the mold. When the
surface of the molten steel approaches the pouring level 76 for the
water-cooled side wall sections 6 and 6', the amount of the molten
steel poured-in is reduced by controlling the stopper 80.
Meanwhile, a shell (hatched part of the cast piece E) which allows
the cast piece to be pulled out is formed on the outer periphery of
the molten steel D in the mold over a period of time, for example,
of 20 to 50 seconds, although the time is different depending on
the cross-section of the cast piece, and then the pull-out of the
cast piece E is started again.
At the moment, when the stepped part F of the casting, which is
formed by the alteration of the width dimension of the cast piece
E, has been shifted downwardly due to the pull-out of the cast
piece E a distance greater than the stroke of the vertical
vibratory movement of the water-cooled mold 1, the vertical
vibratory movement of the water-cooled mold 1 is started.
Then, when the stepped part F of the cast piece E has moved below
the water-cooled side wall sections 7 and 7' as shown in FIG. 13
(d), the positions of the water-cooled side wall sections 7 and 7'
are shifted toward each other so that they coincide with the
positions of the water-cooled side wall sections 6 and 6'.
Then, the molten steel pouring level is lowered to the pouring
level 76 of the water-cooled side walls sections 7 and 7' if
desired by controlling the stopper 80 to continue the continuous
casting.
FIGS. 14a.sub.1 to 14e.sub.1 show steps of altering the
cross-section of the cast piece E from a fixed width dimension to a
larger width dimension. The configuration of the mold set for
casting as shown in FIG. 14a.sub.1 is changed to increase the width
dimension by changing the positions of the water-cooled side wall
sections 6 and 6' as shown in FIG. 14 (b.sub.1). Then, the vertical
vibrating movement of the water-cooled mold 1 is stopped, the
pull-out of the cast piece E is stopped and, as shown in FIG. 14
(c.sub.1), the amount of the molten steel D poured-in is increased
by increasing the opening of the stopper 80 until the pouring level
76 along the water-cooled side wall sections 6 and 6' is reached.
At the same time, the tundish 74 is elevated in response to the
change in the molten steel level in the mold. When the surface of
the molten steel approaches the pouring level 76 along the
water-cooled side wall sections 6 and 6', the amount of the molten
steel poured-in is reduced by controlling the stopper 80.
Meanwhile, a shell (hatched part of the cast piece E) which allows
the cast piece to be pulled out is formed on the outer periphery of
the molten steel D in the mold over a period of time of 20 to 50
seconds, although the time is different depending on the
cross-section of the cast piece.
Then, as shown in FIG. 14 (d.sub.1), the positions of the
water-cooled side wall sections 7 and 7' are changed so that they
coincide with the positions of the water-cooled side wall sections
6 and 6'.
As the upper end parts of the water-cooled side wall sections 7 and
7' are separated from the stepped part F formed by the alteration
of the width dimension of the cast piece E, the vertical vibrating
movement of the water-cooled mold 1 and the pullout of the cast
piece E are simultaneously started.
Then, as shown in FIG. 14 (e.sub.1), the molten steel pouring level
is lowered to the pouring level 76 for the water-cooled side wall
sections 7 and 7' if desired by controlling the stopper 80 to
continue the continuous casting.
In the foregoing there has been described a method of altering the
width dimension of a cast piece so that it is smaller or larger,
wherein the stopping of the vertical vibrating movement of the
water-cooled casting mold has been carried out after the positions
of the upper sections of the water-cooled side walls have been
changed to give the casting the desired dimension. However, the
time of stopping the vertical vibrating movement of the said
casting mold may be before the alteration of the width dimension of
the cast piece.
When altering the width dimension of the cast piece E according to
the method of the present invention, as is explained above, the
vertical vibrating movement of the water-cooled casting mold is
temporarily suspended, and therefore it is necessary to carry out
quick and accurate alteration of the molten steel pouring level in
the water-cooled mold. For that purpose, the tundish 74 may be
provided with a plurality of pouring pipes 75.
When a plurality of pouring pipes 75 are provided, the poured
amount per unit time can be varied widely and the control of the
poured amount can be performed easily.
* * * * *