Note: Descriptions are shown in the official language in which they were submitted.
-- 1 --
The present invention relates to casting
machines, ancl more particularly, to apparatus for
the semicontinuous casting of metal.
The invention is preferably used for the
semicontinuous casting of metal in the production
of solid or hollow castings by drawing up.
Continuous and semicontinuous casting
machines are now finding an ever greater application
in the metallurgical industry throughout the world.
10 The introduction of such machines makes it possible
to substantially reduce the production cycle as
compared to conventional techniques used in foundry
practice. In addition~ these types of machines
allow a considerable saving in time and labour, an
15 extra gain in yield, enhanced production efficiency,
as well as improved working conditions. The castings
produced by such machines have uniform structure and
good properties.
Japanese Pat. No. 45-39345 describes a
20 machine for continuous casting by drawing~up, which
comprises a sealed chamber for molten metal, a
water-cooled mould immersed in the molten metal, a
dummy bar incorporated in a casting withdrawal
mechanism.
The above-described machine is constructed
so as to permit the production of hollow castings
by uphill casting of molten metal into the mould
cavity. This being the case, a solidified layer
and a semisolid layer contiguous thereto are formed
on the working surface of the mould (a solid-liquid
phase). When the two above-mentioned layers reach
a given thickness, the metal meniscus is brought
down to be level with the lower end of the mould.
Thereafter, upon complete solidification of the
~l~8~ 5
semisolid layer, the lower end of the solidified
section is brought up to the top end of the mould
and the metal meniscus is brought down to be level
with the lower end of the solidified section.
The mould cooling system in the above
machine is not provided with a device for forcing
out a liquid coolant from the mould which, con-
sequently, makes it impossible to control the
casting skin formation conditions. Furthermore,
the machine has no device for improving quality of
the inner surface of the casting being produced.
U. S. Pat. No. 3,302,252 discloses a
machine for continuous casting of metal by drawing-
up, which comprises a device for feeding a molten
metal to an air-operated metal supply means having
a metal supply duct. Mounted on the metal supply
means is a mould provided with a cooling system
and having a dummy bar placed on its upper part
and operably connec-ted with a castiny withdrawal
mechanism. There is also provided an appliance
for building up pressure in the metal supply means
and a metal oscillating device.
The pipe casting produced by the machine
has its wall formed on the working surface of the
mould after it is filled with molten metal. The
casting being formed is continuously withdrawn
upwardly from the mould by means of a dummy bar
operably connected to the casting withdrawal
mechanism. In the process of casting formation
the level of molten metal in the mould cavity is
raised and lowered by means of the metal oscillating
device.
The above-described machine has no means
for introducing an inert gas into the interior of
1~8~75
-- 3 --
the casting being formed. The conditions causing
the molten metal to move in the mou]d cavity may
bring about oxidation of the inner surface of ~he
solidified layer, as a result of which -the newly
forming layer will fail to adhere to the casting
skin during subsequent rise of the metal meniscus.
This, in turn, will impair the quality of the
cast product and, in the event of casting aluminium
alloys, will lead to defective products.
An object of the present invention is
to ensure stability of the semicontinuous casting
process.
Another object of the invention is to
improve quality of the cast products.
The foregoing objects of the invention are
attained in a semicontinuous-casting apparatus com-
prising a holding furnace connected through a
closed metal feeding system to an air-operated
metal supply means having a rnetal supplyduct, a
mould with a cooling system arranged on the metal
supply means, and a dummy bar placed on the upper
part of the mould and operably connected to a
casting withdrawal system, wherein, according to
the :invention, the mould cooling system is provided
with a device for forcing out a liquid coolant from
the mould by means of compressed gas, the dummy bar
having a central head adapted to accommodate a
heating element and an adjustable valve for
admitting an inert gas into the interior of the
casting being formed, the casting withdrawal system
having two casting withdrawal mechanisms for alter-
nate cooperation with the dummy bar, of which one
mechanism is operated to pull out the casting from
the mould for a distance not smaller than the length
9L7~
-- 4 --
of withdrawal of the casting minus the length of the
mould, and the other casting withdrawal mechanism is
effective to pull out the casting from the mould for
a distance not smaller than the length of the mould.
Such apparatus construction makes it
possible to produce castings of uniform structure
and good surface quality.
One of the casting withdrawal mechanisms
is preferably provided with a movable platform
having a lever through which the platform is oper-
ably connected with the dummy bar, and a drive; the
other casting withdrawal mechanism is preferably
provided with a movable bar slided in roller guides,
a toothed rack and a member for engagement with the
dummy bar, and a drive.
Such structural arrangement of the casting
withdrawal mechanisms makes it possible to create
favourable casting withdrawal conditions and to
shorten intervals between the casting cycles.
Where hollow castings are to be produced,
the semicontinuous casting apparatus is preferably
provided wlth a device for broaching and sizing the
interior of the cast product, which device is
made in the forrn of a broaching and sizing tool
located in the lower part of the central head,
and a drive which may be the actuator used to
driving one of the casting withdrawal mechanisms.
The use of such device allows the production
of quality castings with adequately sized inner
surfaces.
~he invention will now be described, b~ way
of example only, with reference to the accompanying
drawings, wherein
. , --
-- 5
FIG. 1 is a general view of a semicontinuous-
casting apparatus according to the
invention;
FIG. 2 shows a central head of a dummy bar,
FIG. 3 is a top view oE the dummy bar;
FIG. 4 shows slewing sections of a secondary-
cooling chamber;
FIG. 5 shows a closed system through which
a molten metal is fed from a holding
furnace to an air-operated metal
supply means;
FIG. 6 shows a system through which a
coolant is fed to the mould;
FIG. 7 is a cross-section on line VII-VII
of FIG. 3; and
FIG. 8 shows a dummy bar with a broaching
and sizing tool.
Referring now to the drawings in detail,
and to Figure 1 in particular, a semicontinuous-
casting apparatus comprises a holding furnace 1
which is connected to an air-operated metal supply
means 2 through a closed metal feeding system 3.
The mctal supply means 2 is connected to a compressed
gas feeding system 4. Mounted on the top cover of
the metal supply means 2 is a metal supply duct 5
with a flange being heated. Connected to the flange
of the metal supply duct 5 is a cooled mould 6 having
a cooling system with a coolant source 7 and a device
8 for forcing out a liquid coolant from the mould 6
by means of compressed gas.
The apparatus incorporates at least two
dummy bars 9 w'nich, when required~ are mounted on
the mould 6 prior to starting the next casting
cycle.
-- 6
The dummy bar 9 has a central opening
adapted to receive a central head 10. The central
head 10 has a heating element 11 (FIG. 2) and an
adjustable valve 12. The body of the head 10 is
formed with the holes through which it communicates
with an inert gas supply system 13 (FIG. 1).
Mounted on the dummy bar 9 are two legs 14
formed with holes (FIGS. 1,3) through which the dummy
bar 9 cooperates with a casting withdrawal mechanism
15 or 16 (FIG. 1). ~hen the dummy bar 9 cooperates
with the casting withdrawal mechanism 15, pins 17 of
a lever 18 are introduced into the holes fitted in
the legs 14. If, however, the dummy bar 9 is asso-
ciated with the casting withdrawal mechanism 16,
the holes in the legs 14 receive pins 19 (FIG. 3)
of a movable spring-loaded bracket 20 with a slot
21. The pins 19 of the bracket 20 and its slot 21
are aligned so that the pins 19 are permitted to
enter into the holes provided in the legs 14 of
the dummy bar 9, while the bracket 20 per se, or
rather its section formed with the slot 21, is
accommodate~ in the openings formed in a member of
the casting withdrawal mechanism 16 (FIG. 1). The
casting withdrawal mechanisms 15 and 16 make up a
casting withdrawal system.
The casting withdrawal mechanism 15 in-
corporates a drive (not shown), a feed screw 22 and
a platform 23. The platform 23 bears against the
feed screw 22 and is movable relative to stationary
mounted guide columns (not shown). Movably mounted
on the platform 23 is-the lever 18 with the pins 17.
The casting withdrawal Inechanism i6 is
placed on a trolley 24 for movement along stationary
mounted beams 25 located above the apparatus.
7S
-- 7 --
Disposed above the mould 6 within a length
corresponding to the length of withdrawal of a cast-
ing 26 from the mould 6 is a secondary-cooling zone
27 defined by twin slewing sections made in the form
of at least two shoes 28 (FIG. 4) secured to arms 29.
The shoes 28 are smaller in length than the mould 6
(FIG. 1) and are preferably equal in length to the
maximum di.stance for which the casting 26 is with-
drawn in a single cycle.
The apparatus of the invention has the
following structural features.
The closed metal feeding system 3 intended
for feedi.ng molten metal from the holding furnace 1
to the air-operated metal supply means 2 has a tap
closing appliance which is accommodated ln a chamber
30.
The closed metal feeding system 3 comprises
a tap 31 (FIG. 5) which is formed in a refractory
block 32 and is closed by a gate 33 placed in a
holder 34 through which the gate 33 is pressed
against the refractory block 32. The gate 33 with
the holder 34 is forced against khe refractory block
32 by means of a connecting rod 35. The holder 34
is connected with a lever 36 resting on a pivot 38
fixed in stands 37, and driven by an actuator 39
located externally of the chamber 30.
~itted in the wall of the metal supply duct
5 (FIG. 1) below its heated flange is a hole connected
to a tube 40 which communicates with the compressed
gas supply system 4 and has a shutoff valve 4].. The
tube 40 has one of its ends flaring up towa.rd the
metal duct 5. The inner wall of this part of the
tube 40 has a protective casting preventing adhesion
of the cast metal to the walls of the tube 40. The
- 8 -
tapered end of the tube 40 and the protective coating
facilitate the return of metal r which can penetrate
into the tu~e in the course of operation.
The mould cooling system with the coolant
supply source 7 (FIG. 1) and device 8 for forced dis-
charge of coolant from the mould includes a valve 42
(FIG. 6) for feeding compressed air to the mould 6,
set in a pipeline 43 through which the coolant is
delivered from the mould 6 to the coolant vessel 7.
Set in a pipeline 44, through which a coolant is
delivered from the container 7 to the mould 6, and
arranged in series therein are a relief valve 45
intended to return a liquid coolant to the container
7, and a closed vessel 46 provided with an indicator
47 of the coolant level in the closed vessel 46.
Interposed between the coolant container 7 and the
relief valve 45 is a tube 48 for returning a liquid
coolant.
The casting withdrawal mechanisms 15
(FIG. 1) and 16 are well adapted for rapid alternate
cooperation with the dummy bar 9 in a required
sequence. The first to associate with the dummy bar
9 (FIG. 7) having the legs 14 with holes 49, is the
mechanism 15 (FIG. 1) which is brought in cooperation
with the dummy bar 9 through the pins 17 fixed in
the gu:ide-slided lever 1~ of the movable platform
23. The movable platform 23 is permitted to travel
for a distance equal at least the length of the
casting 26 minus the length of the mould 6.
The casting withdrawal mechanism 16,
mounted on the trolley 24, is constructed so as to
permit the casting 26 to be pulled out for a length
not smaller than that of the mould 6. The mechanism
16 has, slidably mounted on roller guides 50, bars 51
- 9
with a pair of toothed racks 52 fixed thereon and
engaged with a pair of driven pinions 53. The lower
end of the bar 51 carries a member 54 with openings
through which the bar 51 is connected with the
bracket 20 ( FIG. 3) mounted on the dummy bar 9.
Where the casting 26 is to be made hollow,
the semicontinuous-casting apparatus of the invention
is provided with a device for broaching and sizing the
interior of the casting 26. The device in question is
made in the form of a broaching and sizing tool 55
(FIG. 8) located in the lower part of the central head
10, and a drive, which may be an actuator 56 (FIG. 1)
incorporated in the casting withdrawal mechanism 16.
The member 54 of the bar 51 is readily con-
nected and disconnected from a shank 57 (FIG. 8) of
the broaching and sizing tool 55, with the bar 51
(FIG. 1) being made of sufficient length to permit the
central head 10 to travel over the entire length of
the casting 26 being produced.
The central head 10 (F~G. 8) has a valve
58 by means of which an inert gas is fed into the
interior of the castiny 26. The valve 58 is operably
connected with a piston 59. The central head 10 has
two radial ho],es 60 and 61 fitted in the middle part
thereof. The hole 60 is connected to a chamber 62
accornmodating the slidable piston 59, and the hole
61 communicates with a chamber 63 accommodating the
valve 58.
The central head 10 is received in an
opening 64 in the dummy bar 9 and is held in place
by means of rods 65 and 66 which are fitted into
sleeves 67 and 68. The rods 65 and 66 have radial
and a~ial holes. A radial hole 69 in the rod 65
communicates with a radial hole 70 in the rod 65,
then with a hole 71 in the leg 14 of the dummy bar
,~
, - ",
-- 10 --
9, and further with a radial hole 72 ( FIGS. 7 and 8)
as well as with an axial hole 73 in the pin 17 of
the casting withdrawal mechanism 15 (FIG. 1).
Connected to the hole 73 ( FIG. 7) at the
end of the pin 17 is a nipple 74 having a flexible
hose 75 coupled thereto for supplying compressed gas.
An axial hole 76 (FIG. 8) in the rod 66
communicates with a radial hole 77 in the rod 66,
then with a hole 78 in a support stand 79 of the
dummy bar 9, further with a radial hole 80 and a
radial hole 81 in a pin 82 of the casting withdrawal
mechanism 15 (FIG. 1). Connected to the hole 81
(FIG. 8) at the end of the pin 82 is a hose (not
shown) for feeding inert gas.
When used for producing round castings,
the apparatus of the inventin is operated in the
following manner.
After preparatory operations, the metal
duct 5 ( FIG. 1) is heated to a temperature close to
the melting temperature of the metal being cast.
Next, the dummy bar 9 is placed on top of the
mould 6 and then i9 connectd to the casting with-
drawal mechanism 15 by means of the pins 17.
Then, the ai.r-operated metal supply means
2 and the chamber 3() of the closed metal supply
system 3 are blown through with an inert gas, such
as argon, to produce inert atmosphere therein.
This being done, the tapping hole 31
(FIG. 5) is opened as the holder 34 with the gate 33
are moved upwardly through the agency of the lever
36 to permit a required amount of molten metal to
be poured from the holding furnace 1 (FIG. 1) into
the metal supply means 2.
L7S
-- 11 --
Although the amount of molten metal fed to
the air-operated metal supply means 2 usually corres-
ponds to the weight of the casting 26 being produced,
it may be more or less than this weight.
After the metal supply means 2 has been
filled with metal up to a preset level, the tapping
hole 31 is closed by the gate 33 and superpressure
is built up in the chamber 30 and in the metal supply
means 2 with the aid of the compressed gas supply
system 4 (FIG. 1), whereupon the molten metal is
caused to pass through the metal supply duct 5 into
the mould 6, whereby raising the level of metal
(meniscus) until it comes in contact with the lower
end of the dummy bar 9. Gas can be Ereely discharged
from the cavity of the mould 6 through the central
head 10 of the dummy bar 9. In this case the valve
12 (FIG. 2) does not close the outlet 83. However,
in certain cases it may be advantageous for the
molten metal to be fed into the mould 6 with super-
pressure acting on the raising metal meniscus. To
this end, the valve 12 is forced against the outlet
at a preset pressure so as to ensure a required
pressure of gas on the raising metal meniscus.
Normally it takes not more than 3 to 5
sec to fill the mould 6 with molten metal.
Once the mould 6 is filled with molten
metal and the outlet 83 in the central head 10 is
closed, a skin of the casting 26 to be produced is
formed to a preset thickness under conditions close
to those obtained in permanent-mold casting with
superpressure acting from the side of molten metal.
To fulfill this condition, immediately after filling
the mould 6 (FIG. 1) with molten metal or prior to
feeding the molten metal thereinto, depending on the
'7~
- 12 -
possibilities of the mould 6, a coolant is removed
from the cooling channels of the mould 6 with the aid
of the compressed gas ~air) supply system 8. Due to
the heat liberated in the course of metal solidifi-
cation, the walls of the mould 6 are heated to a
required temperature, for example, of 150 to 250C
where aluminum alloys are cast.
Although the liquid coolant continues to
be fed from the coolant supply source 7 at the time
when compressed air is introduced into the channels
of the mould 6, it is immediately recycled to the
supply source 7 through the relief valve 45 (FIG. 6).
The initial formation of the skin of the
casting 26 is carried out in the preheated mould 6
at a preset superpressure. This pressure may be in
the range of 0.5 to 6 ato and over. ~ required
pressure is mounted by means of a compressed inert
gas fed through the compressed gas supply system 4
(FIG. 1).
The casting 26 is formed in the preheated
mould 6 until the skin thereof reaches a thickness
of about 10 to 30 mm, whereupon compressed gas is
discharged from the channels of the mould 6 and a
liquid coolant, such as water, is introduced at a
temperature close to ambient temperature. The rate
of heat removal from the casting 26 is stepped up.
This being done by lowering the temperature of the
walls of the mould 6 and by reason of the fact that
with the supply of coolant the mould 6 is substan-
tially reduced in size and its walls come i.nto closer
contact with the casting 26. In the given case, it
is possible to create conditions under which the
solidified skin of the casting 26 will undergo
external stresses, from the side of the walls of
4~7~
- 13 -
the mould 6, and internal stresses acting from the
side of molten metal. The following example is given
below to emphasize the importance of taking into
account the expansion of the mould 6 caused by high
temperatures of its walls. In the event of producing
a round-shaped casting 500 mm in dia in the mould 6,
formed of aluminium alloy with a hard-anodized work-
ing surface, with the coefficient of linear expansion
of this alloy being 24~10 6 in the temperature range
of 20 to 300C, the inner diameter of the mould 6
will change by 2.4 mm with the change of temperature
of the walls of the mould 6 by 200C. Obviously,
such substantial change in the size of the mould 6
should be given due consideration and should be used
to good advantage.
Further, with the superpressure still acting
on the skin of casting being formed, its formation
continues until it reaches 40 to 60 mm in thickness.
Once the skin of the casting 26 is formed
to a preset thickness, the superpressure acting on
the molten metal through the compressed gas supply
system 4 is released and the liquid coolant is COII-
currently discharged from the channels of the mould
6, whereby it becomes possible to ensure some
expansion of the mould 6 due to its heating. Thus,
favourable conditions are created to enable effective
withdrawal of the casting 26 from the mould 6.
Next, the solidified skin of the casting 26,
the upper part of which is reliably connected with the
dummy bar 9, is rapidly withdrawn (for 3 to 3 sec)
upwardly from the mould 6 by beams of the withdrawal
mechanism 15 for a length not exceeding that of the
mould 6. After the casting 26 has been withdrawn
from the mould 6, the levers 29 (FIG. 4) with the
` s~
/ .,,
- 14 -
shoes 28 are rotated about their axes so as to be
tightly pressed against the casting 26, enveloping
its entire outer surface.
As the casting 26 is withdrawn from the
mould 6, an inert gas is concurrently introduced into
the interior of the casting 26 through the head 10
(FIG. 1) by means of the inert gas supply system 13.
It is possible due to the fact that in the course of
initial formation of the casting 26 the temperature
in the central end part of the casting 26 was main-
tained higher than that of the cast metal by meansof the heater 11 ~FIG. 2) accommodated in the central
head 10.
If the pressure in the metal supply means 2
(FIG. 1) is close to air pressure, then with an inert
gas being introduced into the interior of the casting
26, the molten metal will be rapidly discharged from
the casting interior and it may be completely removed
from the cavity of the mould 6. Therefore, it will
be disadvantageous to bring down the metal level below
the lower end of the mould 6. Ilhus, after introducing
gas into the interior of the casting 26 being formed,
the metal meniscus is first brought down, but not
lower than the lower end of the casting 26. Further,
2S by producing a required superpressure in the metal
supply means 2, the metal meniscus is maintained at
this level and, as the casting 26 is withdrawn from
the mould 6, the metal meniscus is again raised at
the speed not lower than that at which the casting
26 is withdrawn from the mould.
On completion of the casting withdrawal
operation, the metal meniscus in the interior of the
casting 26 continues to be raised until it reaches a
preset uppermost position, while inert gas is dis-
charged from the casting 26 through the central head10 of the dummy bar 9.
/
s
- 15 -
In certain cases, after the casting 26 has
been withdrawn from the mould 6 for a given distance,
it can be pulled slightly backward to make up for the
linear shrinkage of the newly forming casting 26.
The skin formation process in the newly
formed casting 26 is carried out in the cavity of the
mould 6 as described above with reference to the
initial skin formation procedure, i.e. with super-
pressure acting from the side of molten metal and
with the walls of the mould 6 being first heated and
then cooled. The heating of the walls of the mould 6,
i.nitiated still before withdrawing the casting 26
from the mould 6, is continued until the walls are
heated to a preset tempera-ture and after the casting
26 has been withdrawn from the mould 6 when the skin
of the casting 26 is still thin. Then, at a preset
time a coolant is again introduced into the mould 6.
Starting from the formation of the second
portion of the casting 26, in the interval between
withdrawing cycles, the molten metal is continuously
brought up and down in the interior of the casting
26 being formed at a preset rate, for example, at
the rate of 0.5 to 2.0 m/sec. During the above-
mentioned up and down cycles~ an inert gas is di.s-
charged and introduced through the central head 10
in the dummy bar 9. These gas discharging and feed-
ing steps could be carried out with a required super-
pressure being built up on the metal meniscus.
If, for instance, continuous movement of
metal relative to the solidified skin is to be carried
out during initial formation of the casting 26, an
inert gas is introduced before the moment of initial
withdrawal of the casting 26 from the mould 6, where-
upon the above-mentioned conditions will be made
possible.
- 16 -
After the second withdrawal cycle, the second
pair of the slewing sectlons of the secondary-cooling
chamber 27 is operated and the entire production cycle
is repeated until the casting 26 is pulled out to a
preset height.
Further, the skin formation process is
carried on until the casting 26 is completely formed
in the mould 6 without being withdrawn therefrom.
From this moment on, the casting 26 is being formed
until it becomes solid in cross section or until a
preset thickness of its wall under conditions of con-
tinuous up-and-down movement of molten metal inside
the casting 26. It permits the casting 26 being pro-
duced to have sound structure and uniform chemical
composition.
If stringent requirements are not imposed
on the quality of the casting 26, the up-and--down
movement of metal inside the casting 26 is not com-
pulsory to carry out in the course of its formation
to preset si~es.
Where a sound solid casting 26 is required,
the movement of molten metal inside the casting 26 is
discontinued toward the end of the solidification
process and, maintaining the superpressure acting
from the side of the metal supply duct 5, the solidi-
fication of the casting 26 is completed.
The casting 26 is intermittently withdrawn
from the mould 6 for a given distance by means of the
dummy bar 9 in conjunction with the casting withdrawal
mechanism 15. At the end of the withdrawal operation,
the casting withdrawal mechanism 15 is disenaaged
from the dummy bar 9 while the casting withd,rawal
mechanism 16 is concurrently connected thereto. The
platform 23 of the casting withdrawal mechanism 15
~ t7
- 17 -
is brought down to permit its rapid connection (for
10-15 sec) with the next dummy bar 9.
The casting withdrawal mechanisms 15 and 16
are connected to and disconnected from the dummy bar
9 simultaneously. This is carried out as follows.
The pins 17 are brought out of the holes in the legs
14 of the dummy bar 9, and the pins 19 ~FIG. 3) of
the bracket 20 are automatically received in the same
holes of the legs 14. As this happens, the bracket
20 formed with the slot 21 is received in the grooves
provided in the member 54 (~IG. 1) secured to the bar
51 of the casting withdrawal mechanism 16. In this
way, the dummy bar 9 is disengaged from the casting
withdrawal mechanism 15 so as to cooperate with the
casting withdrawal mechanism 16.
With the aid of the mechanism 16, the cast-
ing 26 is completely withdrawn from the mould 6 and
then is conveyed along the guides 25 by the trolley
24 to a special storage.
To enable easy disengagement of the lower
end of the solid casting 26 Erom the molten metal
during its withdrawal from the mould 6, an inert gas
is fed to the place of disengagement throuyh the
tube 40 from the system 4 via the valve 41.
As soon as the casting 26 has been withdrawn
from the mould 6, a new dummy bar 9 is mounted on the
mould 6 for cooperation with the casting withdrawal
mechanism 16. Simultaneously, a new portion of
molten metal is fed from the holding furnace 1 to the
air-operated metal supply means 2.
The metal supply means 2 may be replenished
with molten metal during the casting cycle at a time
when the gas pressure in the metal supply means 2 is
released.
- 18 -
If a hollow casting 26 is to be produced, then
on withdrawi~g the casting 26 for z given length, the
skin formation process lasts until the skin of the
casting 26 reaches a required thickness over the
full vertical extent thereof. Thereafter, the broach-
ing and sizing operations are carried out. To this
end, the rods 65 and 66 (FIG. 8) are retracted from
the central head 10 so as to be disengaged from the
sleeves 67 and 68.
Next, the drive 56 (FIG. 1) is operated to
bring down the bars 51 and, on connecting the member
54 with the shank 57 (FIG. 8), the central head 10
is introduced into the interior of the casting 26.
Here, the tool 55 is brought into use to cut off a
part of the solidified metal from the inside walls of
the casting 26 (broaching) and to effect sizing of
the opening to the diameter of the tool 55.
The cut-off metal is returned to the metal
supply means 2 (FIG. 2) to be melted down therein.
In the course of broaching, the opening in
the casting 26 is not made through but stops 20 to 30
mm short of the lowerend thereof, whereupon the
central head 10 is disengaged from the bar 51 an~
the lat-ter is then lifted and held in place to permit
the slots in the member 54 to be in opposite space
relationship with the slot 21 (FIG. 3) in the bracket
20. Next, the dummy bar 9 is connected with the cast-
ing withdrawal mechanism 16 while the casting with-
drawal mechanism 15 is disengaged therefrom.
Further, the drive 56 is operated to effect
withdrawal of the casting 26 from the mould 6, and the
platform 23 ~.7ith the leuer 23 is brought down to the
lower position so as to be connected by means of the
pins 17 with the new dummy bar 9 mounted on the mould
6.
,.
t7~i
-- 19 --
~ Once Ollt of the mould 6, the casting 26 is
conveyed by the trolley 24 to a specially designed
place where final broaching of its opening is carried
out and the central head 10 is removed therefrom.
As soon as the casting 26 is brought away
from the casting line, the ne~ dummy bar 9 is placed
on the mould 6 for cooperation with the casting ~ith-
drawal mechanism 15 while the central head 10 is
connected by means of the rods 65 and 66 (FI~. 8)
with the compressed gas supply system 13 (FIG. 1).
When all the above-mentioned operations are
completed, a new casting cycle is started.
The semicontinuous-casting apparatus of
the invention makes it possible to produce castings
of good surface and structural quality and of uniform
chemical composition.
In addition, the apparatus is suitable for
the production of hollow castings with a presized
inner surface of high quality.
As a result, it becomes possible to reduce
expenses required for the further mechanical treat-
ment of castings, to diminish the number of defective
castings, and to improve performance characteristics
of the finished products manufactured from the cast-
ings produced by the apparatus of the invention.
l'he production capacity of the semi-
continuous-casting apparatus can be increased 3-
to 6-fold per one strand as compared to conventional
machines of similar type now in use (depending on
the size of the casting being produced and the
amount of metal pouredj. Consequently, a higher
yield is possible with a fewer number of machines,
~hich afford a substantial reduction in capital
investments and operational costs.
