Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~3~6
BACKGROUND OF THE INV~NTION
1. Field of the Invention
The present invention relates to metallurgy and more
in particular to a process and apparatus for continuous
casting of metal in electromagnetic field. The invention
permits a wide choice of metals to be used for casting in-
gots ~y the proposed method.
This invention may find most utility in the production
of ingots by continuous and semi-continuous casting process-
es wherein magnetic field is used for forming the ingot
liquid portion in electromagnetic field in the event of
casting ingots from refractory and easily oxidizable metals
and alloys which do not form sufficiently protective oxide
film on the melt surfaces thereof as well as from alloys
composed of high vapour-pressure alloying components. In
addition~ the invention is readily applicable in the pro-
duction of ingots, effected by means of remelting consumable
electrodes.
2. Description of the Prior Art
For example, U.S.S.R. Inventor's Certificates Nos.
338,037 and 282,615 describe processes and apparatus for
continuous casting of metals in the electromagnetic field
of magnetic inductor functioning as contactless means for
forming the ingot liquid portion, with the side surface of
the ingot being subjected to direct and intensive cooling.
The practice of casting ingots in electromagnetic field
from alumi~num and some of its alloys has been found superior
over a conventional continuous casting process performed
on a continuous cast~ng machine provided with a slidaBle
force-cooled mold. The ingots are produced to have high-
~ 1 --
'
3~6
quality side surfaces and a uniform chem.ical composition
across its section, as well as uniform crystalline structure,
the features substantially improving the ingot workability
and mechanical properties of alloys.
It should be observed, however, that the prior-art
apparatus and processes of casting metal in electromagnetic
field permit the production of quality ingots which are cast
from the metals and alloys which form on their surfaces a
uniform and dense protective oxide film similar to that
formed in the process of casting ingots from aluminum, which
film makes it possihle for the ingot liquid portion to be
supported in the form of a column, with the static pressure
of the ingot metal being slightly increased or the process
conditions, such as the speed of lowering the bottom plate
with an ingot, shocks, the bottom plate vibration~ the rate
of solidification, being slightly varied in the course of
the ingot casting and solidification process.
There are known several types of high-temperature
metals, as well as high-alloyed metals containing highly
volatile components. Where such metals are subject to cast-
ing in electromagnetic field, there takes place violent
turbulence in the ingot liquid zone, caused by high convec-
tive flows of melt in the ingot liquid zone and by vertical
uplift of the bubbles due to the sublimation of the alloying
components. If not damped, such violent turbulence on the
surface of the ingot liquid portion, as well as the discharge
of slag and oxide inclusions, causing nonuniform interaction
with magnetic field, impair the process of formation and
solidification of the side surface of the ingot liquid por-
tion, thereby making it impossible to produce high-quality
ingots. Furthermore~ because of the violent turbulence in
the ingot liquid zone, and in its top portion in particular,
accurate control over the level of the ingot liquid surface
is rendered difficult to carry out in the event of castin~
- 2 -
, . ~
'
1~3~
ingots from the above mentioned alloys. It is known that a
change in the level of the ingot liquid zone brings about
a proportional change in the ingot cross-sectional dimen-
sions. With an excessive height of the ingot liquid zone,
the casting process is disrupted. The aforementioned fea-
tures, specific to the prior-art continuous casting processes
and apparatus, are aggravated to become harmful in the
casting of heavy nonferrous and ferrous metals and alloys
thereof, which form no protective oxide film on the melt
surface, making it possible for the column of the ingot liquid
zone to be supported under the action of electromagnetic
field, which is otherwise spread over at more than 20 per
cent increase in the height of the ingot liquid zone.
It is therefore necessary to minimize detrimental effect
of the ingot liquid zone turbulence on the ingot formation
and solidification process, and to prevent oxide film and
foam from setting onto the ingot side surface.
The aforementioned disadvantages of the prior-art cast-
ing apparatus and processes are mostly due to high sensitiv-
ity of the ingot forming process to slight variations in
the process conditions. Thus, a high sensitivity of the
contactless process of the ingot formation effected under
the action of electromagnetic field is regarded as one of
the basic difficulties encountered in the course of practical
implementation of the known casting process which turns out
to be impractical where high-quality ingots from refractory
and easily oxidizable metals and alloys, not forming suffi-
ciently protective oxide film on the melt surface, are
required.
The above-mentioned disadvantage of the prior-art cast-
ing process is due to the difficulty of ensuring constant
control of the resultant ma~netic field forming the ingot
liquid portion, and of the metal static pressure acting
~ 3 -
~3~
~ertically on the ing~t liquid portion, as well as due to
the absence of low~inertion automatic correction of the ingot
forming process when introducing variations into the process
conditions in t~e course of casting high~temperature metals
and all~s.
It has ~een found that a mere increase in the height
of the ingot liquid portion, for example, by at least 3 to
5 mm, brings about respective increase in the cross-sectional
dimensions Q~ the ingot liquid portion, The casting process
is disrupted as the Balance of forces between the metal
static pressure and that of magnetic field is violated to
exceed the permissi~le level. Variations in the height of
the ingot liquid portions or in the electric parameters of
the magnetic pumping means, as well as variations in the
ingot withdrawing speed, adversely affect the quality of
ingots cast from heavy high-temperature metals and alloys,
such as aluminum-base alloys, which do not form sufficiently
protective oxide film on their melt surfaces, ensuring stable
2Q ingot-forming process.
Metals such as aluminum and some of its alloys do not
reguire good heat protection or protection from oxidation
of the ingot liquid portion, since the oxide film formed
on the ingot liquid portion serves as a reliable protection
from oxidation and, consequently, prevents the formation of
slags and froth-like oxides on the surface of the metal,
even if slightly overheated prior to casting operation.
The metals and alloys, having relatively high melting
and solidification temperatures and being easily oxidizable,
do not tend to form such oxide film on their melt surfaces
as aluminum and some of its alloys-7 ~.oreover, such types of
metals tend to form on their surfaces a thin skin of metal
solidifying on the meniscus of the ingot liquid zone, which
is broken by convective flows of thè melt and is then
~ 4 ~
: ' :
3~;~6
entrained togethex with the slag and oxicle solid inclusions
to be transEerred to the side surEace of the ingot liquid
portion, thereby impairing the ingot forming and solidifying
process~
Attempts ~ave been undertaken to use inert gases as
protective atmosphere above the surface of the liquid portion
of an ingot formed in magnetic field. For example, the
U.S.S.R. Inventor's Certificate No. 455,794 describes an
apparatus for casting metal in magnetic field. The appara-
tus is provided with a cover which closes the ingot-forming
cavity and has a pipe for protective gas to be applied there-
throug~. To prevent the atmosphere air from penetrating
into the ingot-forming cavity, a funnel-shaped element is
fixed below the water supply level and is filled with the
water flowing off the surface of the water-cooled ingot and
forming a steam blanket between the supplied inert gas and
ambient atmosphere.
The apparatus described above allows only inert gases
to be used as the protectiVe atmosphere.
However, it is like~ise impossible to ensure the produc-
tion of ingots with high-quality side surface from alloys
; 25 the components of which have relatively low boiling point
and, therefore, would prefer to have their liquid surfaces
protected with flux melts. The use of flux melts at this
type of apparatus is impossible because of the fact that
such melts will flow off the ingot horizontal liquid surface
onto the side surface thereof to interact with a cooling
water. Since the apparatus cannot be hermetically sealed,
it does not allow the use of vacuum,
From the above it follows that the prior-art apparatuses
and processes for continuou~ casting of metal in electromag-
netic field do not perm~t, on account of characteristic
-- 5
.
,
features inherent in the procedure of contactless formation
of the ingot liquid portion in magnetic field and intensive
direct cooling of the ingot side surface, the production
of high-quallty ingots from high-temperature and easily
oxidizable metals and alloys wh:ich do not permit sufficiently
protective dense oxide film to be formed on the ingot liquid sur-
face as, for example, aluminum-base alloys, as well as from
alloys having high vapour-pressure components included
therein.
The prior-art casting processes in question fail to
provide necessary protection to the upper portion of the
ingot liquid zone from undesired losses of heat; the side
surface of the ingot liquid portion being left unprotected
from penetration of slag or oxide films with solid metal
inclusions from the upper portion of the ingot liquid zone.
This results in the impairment of appropriate conditions
required for uniform formation of the ingot liquid portion
and disturbs uniformity in the ingot solidification at the
side surface thereof.
;
Furthermore, it is impossible to protect the entire sur-
face of the ingot liquid portion with a layer of protective-
degassing flux or to provide protective rarefied atmosphere
thereabove.
Where ingots are cast from an alloy with high vapour-
pressure components, for example, zinc in brass, the escape
of vapours through the open surface of the ingot liquid por-
tion impairs the ingot forming process accompanied by violentturbulence of metal in the ingot liquid portion and results
in the appearance of flaws on the ingot side surface and
its peripheral layer.
35The known casting processes of the type described above
fail to provide for the production of presized ingots, or
-- 6 ~
~ , ,
...~
~3~Z6
ingots with the cross-sectional profile thereof being differ-
ent from the cross-sectional profile of the ingot liquid
portion.
Such processes are unsuitable for the production of in-
gots having on their side surfaces a layer of metal with
chemical composition thereof being different from that of
the ingot metal, for example, a layer of solidified flux
protecting the ingot surface from oxidation, or a layer of
clad metal, or else a thin layer of alloy, for example,
copper tin, copper lead on copper ingot.
The disadvantages inherent in the prior-art casting pro-
cesses and apparatuses make it impossible to combine a
highly efficient process of casting high-quality ingots in
magnetic field with a casting process effected by means of
melting consumable electrodes.
However, the problems posed by general and metallurgi-
cal engineering demand urgent solutions required to further `
improve the known processes and apparatuses for casting
metal in magnetic field. The expected solutions to these
problems have enormous practical significance for the pro
duction of ingots from refractory easily oxidizable metals
and alloys thereof, such as iron, nickel, titanium, copper,
silicon, germanium, as well as from the alloys containing
high vapour-pressure components, such as, for example, zinc
and aluminium, i.e., from the metals and alloys which, unlike
aluminum, do not permit a sufficiently dense protective
oxide fi~m to be formed on the surface of the liquid portion
of the ingot solidifying under the action of electromagnetic
field.
SUMMARY OF THE INVENTION
Tt is a primary object of the invention to provide a
~ 7 ~
:
.
3~6
process for continuous casting of metal in electromagnetic
field, which will enable the production of high-quality
ingots from the metals which require protective medium from
gases, slag or flux melts; also permitting the use of rare-
fied atmosphere or vacuum.
Another important object of the invention is to provide
an apparatus for continuous cast:ing of metal in electromagne-
tic field, which ~ill permit a melt to be used as the pro-
tective medium.
Another object of the invention is to improve the qualityof the side surface of an ingot to be produced in strict
conformity with specified cross-sectional dimensions and con-
figuration.
Still another object of the invention is to improvequality of the ingot metal.
These objects and features of the invention are accom-
plished by the provision of a process and apparatus for
continuous casting of metal in electromagnetic field. The
process of the ;nvention includes the steps of delivering
a molten metal onto a bottom plate disposed in electromagne-
tic field acting to support the molten metal in the form of
a column, providing a protective medium at least at the
horizontal liquid surface of the ingot metal, and supplying
a coolant to the side surface of the solidified ingot.
T~e provision of protective medium above the ingot
liquid portion permits the continùous casting process to be
carried out in electromagnetic field wherein use can be
made of such metals and alloys which do not allow sufficient-
ly protective dense oxide film to be formed on the surface
of the ingot liquid portion, and more in particular from the
~ 8 -
~"~
.
' ~ ' .
3~
metals and alloys whic~, when in molten state, require pro-
tection from oxidation and heat dissipation due to physico-
chemical characteristic properties thereof.
S It is preferable to use the melt of conducting slag and/
o~ degassi.ng flux as the protective medium.
The provision of a layer of molten conducting slag on
the surface of the liquid portion of an ingot cast in elec-
tromagnetic field permits the production of high-quality
ingots from hig~-temperature metals and alloys which, by
virtue of their nature, require good heat protection to be
afforded to the liquid upper portion of the ingot. This is
necessary for eliminating the conditions which permit the
solidified portions of metal to be formedon the liquid upper por-
tion of the ingot, tending to slide off onto the liquid
side surface of the ingot, thereby impairing the process of
the metal solidification and its formation into the ingot
with high-quality metal and smooth side surface.
The use of degassing flux as the protective medium
permits the production of high-quality ingots from metals
and alloys which require additional treatment before being
fed to the forming and solidifying zone, whereby physical
and mechanical properties of metal are substantially improv-
ed. With the process of the invention it becomes possible
to improve both the quality of the ingot metal and the
quality of the ingot surface. In addition, favourable con-
ditions are created for combining the process of electroslag
melting of consumable electrode with the process of casting
metal in electromagnetic field.
The melt used as protective medium is preferably held
in place at the side surface of the ingot liquid portion
by means of a ~unnel-shaped band formed with an annular
section fixmly attac~ed to the skin of the solidifying ingot
g _
; ' '''
.
~3~
above the level from which a coolant is supplied to the ingot
side surface.
This will permit protection to be afforded not only to
the upper horizontal portion of the ingot molten surface, but
to the side surface of the ingot: liquid portion as well. In
this case, slag or degassing flux can be used as the protec-
tive melt.
~ layer of molten metal wit:h chemical composition there-
of being different from that of the ingot metal is preferably
provided around the side surface of the ingot molten metal.
The provision of a layer of molten metal disposed around
the side surface of the ingot li~uid portion and having chemi-
cal composition different from that of the ingot metal en-
ables the production of an ingot with a thin peripheral layer
from a desired metal. In other words, it becomes feasible
to produce a composite ingot or to effect surface alloying of
the ingot base metal.
The ingot-forming metal is preferably delivered in an
amount sufficient for building up constant metal static pres-
sure with a value thereof being 5 to ~0 per cent in excess
o the rated value of the electromagnetic field compression
pressure, as the skin of solidifying ingot is concurrently
sized by means of the annular section of the funnel-shaped
band with the cross-sectional size and shape thereof being
selected in conformity with a specified cross-sectional
size and shape of the ingot being cast.
~ ith the afore-indicated excess of the metal static
pressure over the compression pressure o~ electromagnetic
field, and with the ingot skin ~eing concurrently subjected
to sizing, it becomes possible to produce the ingot in strict
con~ormity with a desired shape and size thereof. If acted
lQ -
.:
.. . .
,.
~ '
~1~3~6
upon radially in the direction of the longitudinal axis, the
ingot skin is deformed; and provided the ingot liquid portion
is of circular or oval shape, a solid ingot is produced to
be polygonal in cross-section, for example, pentagonal, hexa-
gonal or octagonal, with clear].y defined sides and edges.
Thus, with relatively simple construction of the electromag-
netic mold it becomes possible to produce ingots of complex
cross-sectional profile, which is of great practical signi-
ficance.
There is also provided an apparatus for carrying into
effect the process according to the invention for continuous
casting of metal in electromagnetic field, which apparatus
comprises, mounted on a frame in coaxial arrangement with
one anoth.er, a baffle, an electromagnetic inductor and a
cooler, all of which are annular in shape and set around the
ingot forming space defined from the bottom by a bottom plate
and from the top by a cover formed with an inlet opening
for the passage of molten metal, with an opening for the rod
of a metal level gauge to extend therethrough, and with an
opening for the protective medium to pass therethrough,
wherein, according to the invention, there is provided at
least one shell positioned beneath the cover and fixed on
the baffle by means of its flange in a manner to allow the
lower end face of the shell to be immersed in the molten
metal of the ingot, the shell being formeu with a refrac-
tory nonmagnetic material chemically inert to a melt of flux
or metal and having low heat conductivity.
Such apparatus construction permits a protective medium
to be provided above the surface of the ingot molten metal,
necessary for several types of metals and alloys unsuitable
for the production of ingots at prior-art apparatus of
similar type. It is possible to use an inert gas, the melt
of conducting slag or degassing flux as the protective medium.
~I
....
The apparatus of the invention allows for melting consumable
electrodes when forming ingots in electromagnetia field. In
addition, with the shell being immersed in the surface layer
of the ingot liquid portion, the melt of slag or flux is
retained within the shell cavity on the upper horizontal
liquid portion of the ingot.
The material selected for the shell must be sufficiently
resistant to the action of high temperatures, chemical sub-
stances and electromagnetic forces.
The provision of the shell immersed in the liquid portionof the ingot makes it possible to stabilize the ingbt form-
ing and solidifying process while casting ingots in electro-
magnetic field from metals and alloys which do not form ontheir surface sufficiently protective oxide film (such, for
example, as aluminum and some of its alloys), as well as
to prevent the oxides and slags found on the upper portion o
the ingot liquid zone from getting to the solidified ~one
thereof.
The provision of the cover makes it difficult for the
molten metal to solidify on the meniscus of the ingot liquid
portion. The provision of the shell and cover allows for
the space to be provided above the ingot liquid portion and
required for a protective medium to be disposed therein,
also making it possib~e to reduce the losses of heat and
of the metal volatile components.
It is preferable to provide a second shell spaced ex-
ternally of the and coaxially with the first shell and fixed
on the baffle, with the interior dimensions thereof being
made such as to enable its contact with the upper portion of
the ingot side surface.
Such external sfiell permits the protective layer of
12 -
. ~ ,~ . .
'~ ` ' ~ ` ,
- ~ j
3~26
melt to be retained over the entire horizontal molten surface
of the ingot. Furthermore, a part of the ingot side surface
is protected by the external shell from oxidation; the
sublimation of the volatile alloy components with high vapour
pressure also ~eing reduced.
The external shell is preEerably formed of a material
having its physical density 4 to 6 times lower than that of
the ingot liquid portion, and, formed internally of the
shell, is a horizontal section having fixed thereto a rod
of a metal level gauge; the shell per se being freely inter-
posed between the internal shell and the baffle, and having
- its interior dimensions made such as to enable its contact
with the upper portion of the ingot side surface, as well
as the contact of its horizontal portion with peripheral
section of the horizontal molten surface of the solidifying
ingot.
Such shell is floatable on the upper molten surface of
the ingot, whereby detrimental effect of the melt turbulence
on the ingot forming process is substantially decreased;
the control over the varying level of the ingot liquid por-
tion is greatly improved, with the level of metal being
maintained within a prescribed range, in particular, in
those instances when ingots are cast from metals and alloys
the components of which have relatively low boiling points.
The external shell is preferably fixed on the baffle
by means of its flange and has its interior dimensions form-
ed such as to provide at the upper portion thereof a gapbetween its in~erior surface and the liquid portion of the
ingot side surface, the lower portion of the shell being
disposed to the ingot-forming zone and formed with a ring-
shaped sizing band having its opening area sized and shaped
in conformity with a specified size and shape of the finish-
ed ingot.
- 13 -
,~
: "
3~l~6
The provision of the external shell, the upper portion
of which remains clear of the ingot liquid portion and the
lower portion thereof envelopes the solidifying side surface
of the ingot skin to there~ effect its sizing, permits the
casting process- to he effected so as to provide complete and
reliable protection to the entire molten portion of the
ingot surface with an inert gas, degassing flux and/or con-
ducting slag, as well as with a rarefied atmosphere. This,
in turn, makes it possible to conduct the continuous casting
process in electromagnetic field by utilizing such metals
and alloys thereof that at all times require protection from
heat losses and from oxidation as, for example, copper,
magnesium, iron, nickel, zinc, silicon, titanium, etc.
The external shell is preferably formed such that its
interior dimensions constitute 0.85 to 1.15 times the respec-
tiVe dimensions of the sizing band, the height of which is
1~2 to 2/3 of the height of the magnetic inductor, the lower
end face of the shell being positioned below the transverse
axis of the magnetic inductor within a distance of 1/4 to
2/3 of the height of the magnetic inductor.
The interior dimensions of the shell have been selected
with due regard to the nature and extent of shrinkage of
the ingot metal during its cooling. Where ingots are pro-
duced from metals and alloys tending to grow in volume during
their solidification, the interior cross-sectional dimensions
of the opening area of the shell upper portion will respec-
tively be smaller than the dimensions of the sizing section.
With the height of the sizing section being 1/~ to 2/3
of the inductor height, as ~ell as with the end face of the
shell being disposed below the level from which starts the
ingot-forming zone, the sizing is effected until the ingot
side surfaces are partiall~ relieved from strain, and the
static pressure of metal ~ithin a permissible range~ is
- 14 -
'~
.~ ~
~3~26
lowered.
The provision of the sizing section at the lower portionof the shell, acting radially on the ingot hot plastic skin
in the direction of its longitudinal axis, permits the pro-
duction of ingots sized in cross-section throughout their
lengths, as well as of ingots having their cross-sectional
profiles different from that of the ingot liquid portion. In
other words, with a relative shape and construction of the
magnetic conductor, a contactless ingot forming process is
enabled to permit the production of circular-, and oval-
shaped ingots, pentagonal, sextagonal and octagonal in cross-
section and having clearly defined sides and edges thereof.
Advantageously, the side walls of the interior shell
are formed with perforations and are interconnected by means
of a transverse perforated partition.
The provision of perforations in the side walls of the
interior shell permit a uniform layer of protective medium
to be disposed above the molten surface of the solidifying
ingot, and the pressure of the metal jet passed through a
header into the ingot-forming zone to be reduced. An origin-
al powerful jet of metal is divided into several metal jets
uniformly distributed across the ingot liquid zone, thereby
permitting convective displacements of the melt to be sub-
stantially reduced and the quality of the ingot metal to be
improved.
The wall of the external shell is preferably formed
with gating channels intended for the supply of metal having
its chemical composition different from that of the ingot
metal, which channels are provided in the gap between the
external shell and the lateral liquid surface of the solidi-
fying ingot~
;
'
: .
:,
,. ~
31~6
The provision of gating channels in the wall of the
external s-hell permits a layer of molten metal to be formed
around the lateral surface o~ the ingot liquid portion, the
chemical composition of which differs from that of the ingot
metal, whe~eby composite ingots or those clad with peripheral
metal layer are possi~le ta produce.
The cover is preferably formed with anobservation open-
ing intended for effecting visual control over the techno-
logical process, the state of the molten surface of thesolidifying ingot, and over the supply of protective medium,
such as slag or flux.
It is preferred to have the wall of the external shell
formed with through openings intended for the protective
medium to pass therethrough, which is supplied to the molten
lateral surface of the solidifying ingot.
The through openings formed in the walls of the exter-
nal shell are also intended for the supply of an agent usedas the protective atm~sphere beyond the wall of the external
shell in the zone of electromagnetic field.
The flange of the interior shell is preferably formed
with observation openings required for visual control over
the state of the upper liquid portion of the solidifying
ingot~
BRIEF DESCRIPTION OF THE DRAWINGS
. . _
The invention will be further described, by way of
example only, with reference to the accompanying drawings,
in which:
35Fig. 1 is a longitudin~l view, partly in section, of
an apparatus fox continuous casting of metal in electromag-
- 16 -
~, ... ~
~3~
netic field according to the invention;
Fig. 2 is a longitudinal vie~ of a continuous casting
apparatus provided ~it~ two shells;
Fig. 3 is a schematic vie~ of an apparatus provided
with an external floating shell;
Fig. 4 is a view of an apparatus provided with an ex-
ternal shell formed with a sizing band.
DET.~ILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The process according to the invention for continuous
casting of metal in electromagnetic field is carried outas follows.
A ~olten metal to ~e cast into ingots is delivered onto
a bottom plate disposed in electromagnetic field produced
2Q ~y a magnetic inductor annular in shape. Electromagnetic
field is maintained so to enable the molten metal to be
supported in the form of a column in a conventionai manner.
According to one embodiment of the invention, the pro-
cess is carried out with the use of a protective mediumpreferably, a melt or vacuum Crarefied atmosphere). However,
inert gases are likewise suitable for the purpose, which
procedure is described in one of the known methods. A cool-
ant is supplied to the bottom plate and onto the side sur-
face of the solidified ingot, the cooling operation beingalso effected in a conventional manner.
The dist~nctive feature of the proposed process, how-
ever, lies in that protective medium is provided at least at
the horizonta:L liquid portion o~ the ingot metal surface.
The ingot castin~ process iS effected in electromagnetic
- 17 -
, . . . .
' ~ , ~- - . ;
,
.
-
"
. .
26
field, wherein use is made of chemically active ~nd easilyoxidizafile metals and alloys which do not form on their
molten surfaces sufficiently dense and protective oxide film.
Conducting slag and~or degassing flux are selected in accor-
dance with the chemical composition of the inyot metal,providing either complete or partial protection to the ingot
melt surface by means of melt. Thereafter, it is possible
to commence the ingot casting p:rocess, utilizing for this
purpose high-temperature metals and alloys in need of heat
protection to be afforded to the upper liquid portion of the
ingot surface.
According to another embodiment of the invention, the
upper liquid portion of the ingot is hermetically sealed
and the ingot is cast under vacuum. As this happens, use
is made of a funnel-shaped band with an annular section
closely adjoining the ingot solidifying skin.
Such funnel-shaped band can be readily employed in other
embodiments of the in~ention, wherein use is made of pro-
tective flux or slag~ To this end, the gap between the
liquid portion of the ingot surface and the interior surface
of the funnel-shaped band is filled with conducting slag
or degassing flux, thereby affording protection both to the
upper and to the lateral molten surface of the ingot in the
course of casting pxocess effected in electromagnetic field.
As a result, the quality of the ingot metal, as well as the
lateral surface of the ingot, are improved.
~here it becomes necessary to produce an ingot having
its lateral surface formed with the layer of metal having
its chemical composition different from that of the ingot
metal, as in the case of surface coating of the ingot base
metal or in the case of composite ingots, the melt of this
metal is poured into the gap bet~een the ingot and the
funnel~shaped band, as described in the preceding embodiment
- 18 -
3~Z~
of the invention.
According to t~e preferred em~odiment of the invention,
a molten metal is delivered in an amount sufficient for
build~ng up constant ~etal static pressure with a value
thereof be~ng 5 to 2Q per cent :in excess of the rated value
of the electroma~netic field compression pressure, as the
siz~ng of the ingot solidifying skin is concurrently effect-
ed by means of the funnel-shaped band. The size and shape
of the opening area of the funnel-shaped band is selected
in accordance wlth a specified size and shape of the ingot
being cast.
By effecting the casting process of the invention in
the a~ove-described manner, t~e ingots are produced in
strict conformity with a specified size and shape, for exam-
ple, pentagonal, sextagonal or octagonal ingots having
clearly defined sides and edges. It also becomes possible
to utilize for the continuous casting process effected in
electromagnetic field suc~ metals as copper, magnesium, iron,
zinc, silic~n, titanium, etc~
The process of the invention has great practical signi-
ficance, since the continuous casting of metal effected in
electromagnetic field permits the~ production of high-quality
inyots from refractory and easily oxidizable metals and
alloys, as well as from alloys containing high vapour-pres-
sure components, for example, such as zinc or cadmium in
copper alloy; in other words, from metals and alloys which
do not form on their surfaces sufficiently protective oxide
film necessary for stabilizing t~e process of contactless
formation of ingots, the metal of which, by nature of its
physicochemical characteristics require reliable protection
from oxid~tion and heat losses, due to take place at the
meniscus of ~ts uppe~ portion~
.
'
~3~6
The continuous casting process of the invention is
carried into effect By means o an apparatus having various
constructional embodiments.
For example, where protect.ive medium, such as a melt
or inert gas is provided only at the horizontal portion of
the ingot melt surface, it is preferable to use the appara-
tus shown in Fig. 1.
The apparatus of Fig. 1 comprises, mounted on a frame
in coaxial arrangement with one another, a ring-shaped baffle
2, a magnetic inductor 3 and a cooler 4. An ingot 5 with
an upper liquid portion 6 is positioned on a bottom plate 7.
According to the invention, the apparatus is provided with
a shell 8 having its top part closed with a cover 9. The
shell 8 is formed of a refractory nonmagnetic material
chemically inert to a protective melt and having low heat
conductivity, for example, such as graphite or ceramics. In
the given embodiment of the invention, there is used only
one shell 8 formed with an external flange 10 by means of
which it is fixed on the baffle 2. To vary the depth of
immersion of the shell 8 in the liquid portion 6 of the
ingot 5, adjustment screws 11 are provided for the purpose.
The cover 9 is formed with a central through opening to
receive a header 12 through which a molten metal is deliver-
ed to ~e formed into an ingot. In addition the cover 9 is
formed with a through opening 13 through which extends a
: rod of a float gauge 14 for measuring the level of molten
metal in the upper portion 6 or the ingot 5. A melt lS of
conducting slag of degassing flux can be delivered onto the
surface of the liquid portion 6 of the ingot 5 through the
header 12, and a shielding gas may be fed through a tuhe
16 and discharged through an opening 17 formed in the walls
of the shell 8. The cover ~ can ~e formed of several
plates arranged one above the other in the groove of the
shell ~. Coaxial alignment of the respective openings in
20 -
.
~3:~Z~:~
the plates and a size of the gap therebetween i9 ensured ~y
an appropriate depth o~ the grooves and stop mem~ers provided
in the body of the s~ell 8. The ~all of the header 12 is
formed with an opening 18 intended for the metal to be dis-
charged therethrough in jets uni~ormly distri~uted in vari-
ous directions underneath the surface la~er of the molten
metal.
The apparatus operates in the follo~ing manner. Prior
to starting the ingot-for~ing process, the shell 8 is adjust-
ed by means of the adjusting screws 11 at a level ensuring
a prescri~ed depth.of immersion of the lower end portion of
the shell 8 in the liquid portion 6 of the ingot 5. Thence,
the bottom plate 7 is introduced into the zone of magnetic
field so that the upper edge of its lateral surface extend
5 to 10 mm short of the transverse axis of the inductor 3.
Thereafter, the inductor 3 is energized and a coolant is
fed from the cooler 4 to the lateral surface of the bottom
plate 7. The shell 8 is preheated to a temperatur.e of 500
to 800 C and a molten metal is delivered onto the bottom
plate 7 through the header 12 to be formed into the ingot 5.
~hen acted upon by electromagnetic field of the inductor 3
the molten metal i5 formed into a column having the lower
end face of the shell 8 immersed therein to a depth of 5 to
10 mm, a portion of molten conducting slag or degassing flux
is fed through the header 12. The melt 15 is maintained on
the surface of the li~uid portion 6 of the ingot 5, thereby
protecting the latter from oxidation and preventing exces-
sive losses of heat from the meniscus of the liquid portion
6 of the ingot 5. If necessary, inert gases can be used
as additional protection to the lateral surface of the ingot
molten metal, ~ed in streams t~rough the tube 16 underneath
the cover 9 into the interior of the shell 8 and discharged
through the openings 17 in t~e ~all of the shell 8 and the
upper liquid portion 6 o~ ;n~ot 5 is ~ashed by these streams.
- 21 -
~ ' .
~1~3~
The control over the level of the liquid portion 6 of
the ingot 5 is effected either by means of the float le~el
gauge 14 or visually by inspecting the open lateral surface
of theliqu~d portion 6 of the ingot 5~ In the course of
5 casting, the shell 8 immersed in the melt 15 ~elow the level
of the ingot liquid surface over the perimeter of the liquid
portion 6 of the ingot 5, serves to prevent oxide and slag
solid nonmetallic inclusions from sliding off onto the
lateral surface of the ingot liquid portion. As a result,
the ingot forming and solidif~ing process, effected in elec-
tromagnetic field, is stabilized.
Owing to the provision of a layer of protective degassing
flux or condu-cti~g slag, serving as the heat protection for
the meniscus of the ingot liquid portion, as well as due to
the heat-shielaing affect produced by the cover 9, with the
oxides~and slag inclusions being prevented by the shell 8
from getting onto the side surface of the ingot liquid por-
tion, as protective atmosphere is concurrently created above
the melt, spontaneous crystallization of metal on the menis-
cus of the ingot liquid portion is not permitted, and the
split particles of the solidified metal and oxide or slag
inclusions are prevented from getting to the lateral surface
of the ingot liquid portion.
Thus, the resultant ingot, produced from metals such
as, for example, copper, bronze, silicon brass, etc., that
is from high-temperature and easily oxidizable metals and
alloys, which, unlike aluminum and alloys thereof, do not
form on their melt surfaces sufficiently protective oxide
film, have sound crystalline structure and smooth side
surface~
The apparatus according to another embodiment of the
invention, shown in Fig~ 2, comprises two shells.
- 22 -
,,
~a~3~
This apparatus differs from the previously described
one in that it has a second shell 19 arranged coaxially with
and externally of the ~irst shell 8. The shell 19 has its
interior dimensions formed SUCh as to enable its contact
~ith the upper portion 6 of the latexal molten surface of the
ingot 5. The shell 19, like the shell 8, is formed o~ a
refractory nonmagnetic material chemically inert to the
melt and having low heat conductivity. The shell 19 bears
up against the baffle 2, and the shell 8 has its flange 10
thrust up against the shell 19. The float gauge 14 is pre-
ferably accommodated in the annular gap between the shells
8 and 19. The wall of the shell 8 is formed with ducts or
passages 20 intended for the melt to flow therealong into
the gap between the shell 8 and 19. Both the cover 9 and
the flange 10 of the interior shell 8 are preferably formed
'with ofiservation openings 21 intended for visual control
over the melt surface of the liquid portion 6 of the ingot
5. All the ~asic structural elements of the apparatus of
this embodiment are similar to those of the previously des-
cribed one, including the tube 16 for the supply of inertgas, the opening 17 formed in the wall of the shell 8, and
the ~pening 22 formed in the external shell 19 and intended
for the passage of inert gas therethrough. The process for
the continuous casting of metal in electromagnetic field is
effected essentially as described above in the first embodi-
ment of the invention. Mounted on the magnetic baffle 2 is
the external shell 19 whereupon is mounted the internal shell
8 with the cover 9, header 12 and float gauge 14, so as
to prevent the lower end face of the external shell 19 from
contacting the solidifying lateral surface of the ingot,
while allowing the lower end face of the interior shell 8
to be immersed in the molten metal, to a depth of 5 to 15 mm.
Prior to feeding the molten metal or a melt of flux or slag
to the zone of electroma~netic field of the inductor 3, the
shells 8 and lY, as well a,s the elements pertaininy thereto,
are heated to a temperature of 6Q0 to 800C.
- 23 -
- ,
.. ..
26
The hott~m plate 7 is also arranged in the zone of elec-
tromagnet~c field o~ the inductor 3~ The inductor 3 is ener-
gized and the coole~ 4 is operable to supply a coolant to
the side sur~ace of the bottom plate 7. Thereafter, the
molten metal is delivered onto the bottom plate 7, whereupon
the molten metal solidif~es and forms into an ingot. The
moment for lowering the bottom plate 7 is determined by the
level of the liquid portion 6 of the ingot 5, which level is
controlled visually through the observation openi.ngs 21 and/
or by the readings of the metal level float yauge 14.
If necessary, theingot casting process can be effected
by feeding an inert gas serving as the protective atmosphere
for the liquid portion 6 of the ingot 5, and fed to the
ingot casting and forming zone through the tube 16, openings
17 in the ~all of the interior shell 8, and through the
openings 22 in the wall of the exterior shell 19. In the
event of using conducting slag or degassing flux in the cast-
ing process, these are fed onto the surface of the molten
metal through the header 12, whereupon the melt is spread
over the surface of molten metal and overflows from the cav-
ity of the interior shell 8 through the passages 20, formed
in its walls, and into the gap between the shells 8 and 19.
The apparatus described in the second embodiment of
the invention permits the ingot forming and solidifying pro~
cess effected in electromagnetic field of the inductor 3 to
be substantially stabilized, and the quality of ingots,
especially of those produced from easily oxidizable metals
and alloys, as well as ~rom alloys comprîsing low-melting-
temperature components, such as zinc in brass or cadmium
in bronze, to be improved.
The apparatus of the invention is suitable for perform-
~n~ the casting process under a layer of degassing fluxl
which makes ~t possi~le to substantially reduce the loss of
. - 2~ -
. . ' ' '
. ' ' '
. ' .
~3~
hi~h vapaur-pressure components, such as ~inc, cadmium and
phosphorus in copper allo~s, escaping from the melt, The
protection a~forded ~y the shell wall to the side surface of
the i~n~ot li~uid portion permit.s the rate of melt oxidation
S to be materiall~ decrea~ed and the loss of the low-melting-
point alloy components escaping therefrom to be reduced.
Thus, as a result of the protection afforded by a layer
of degas-sing flux to th.e entire upper portion of the ingot
liquid zone, as well as the protection froTn oxidation afford-
ed to the ~reater part of the side surface of the ingot
liquid zone ~y the wall of the shell 19, it becomes possible:
- to substantially reduce the loss of the low-melting-
point alloy components escaping from the melt which, in turn,
permits undesirable and uncontrolled turbulence of the ingot
liquid portion to be eliminated to a great extent, whereby
the quality of the ingot side surface and in the peripheral
layer thereof is improved;
- to substantially reduce the loss of heat by means of
a melt and, consequently, to lower the casting temperature
by 20 to 40C, as compared to the prior-art continuous cast--
ing processes and apparatuses employed for similar purpose;
- to substantially reduce the extent of oxidation of
the ingot liquid portion, preventing the formation of oxides
on the lateral surface of the ingot liquid zone as well as their
penetration to th.e ingot solidified lateral surface in the
course of the ingot forminy and solidifying process.
The protection of the upper portion of the ingot liquid
zone effected by means of flux and of the ingot side sur-
face by means of the wall of the external shell permits the
ingot forming process and the solidification of the side
surface of the ingot metal, be it from brasses or bronzes
containing high va.pour-pressure alloy components, to be
considerably stabi~lized~ ~ith the apparatus of the invention
it is ~easi~`le to produce in~ots from ~rasses and bronzes,
~ 25 -
~ ' ~
, . .
2G
with high-quality side suxfaces and sound crystalline
structure,
Shown in Fig. 3 is another embodiment of the invention,
5 comprising a floating shell 23 formed of a material having
its physical density 4 to 6 times lower than that of the
melt of the ingot liquid portion. The shell 23 is provided
with a flange formed internally thereof. Arranged adjacent
the flange and fixed on th.e horizontal section 24 thereof
is a rod of a means 14 for gauging the level of molten metal
of the liquid portion 6 o~ the ingot 5. The shell 23 is
positioned freely in the interspace between the interior
shell 8 and the baffle 2. The shell 23 has its inner dimen-
sions formed such as to enable its contact with the upper
portion 6 of the lateral molten surface of the ingot 5, as
well as the contact of the shell horizontal section 24 with
the peripheral section 6 of the liquid horizontal surface
of the ingot 5.
The internal shell 8 bears up against brackets 25 having
mounted therein adjusting scre~s II intended for altering
the depth of immersion of the shell 8 in the melt 15, irres-
pective of the displacements of the baffle 2, magnetic induc-
tor 3 and annular cooler 4. The cover 9 closing the shell
8 is formed with an opening intended for the header 12 to
extend therethrough, which header is used for the supply of
molten metal, degassing flux or conducting slag to the zone
of the ingot forming effected in electromagnetic field. The
cover 9 also has a tube 16 intended for the passage of inert
30 gas therethroughThe walls of the internal shell 8 is
formed with openings 17 intended for the passage of gas to
~e used as the protective atmosphere set beyond the confined
of the shell 8, the bracket 25 being provided with an open-
ing to receive therein the rod of the metal level gauge 14.
- 26 -
i .
: . . .
3~
The side surface of the internal shell 8 is formed
with a ~ojection, such as shown in Fig. 3, which is intend-
ed f~r f~xin~ t~e i~nternal shell 8 to the bracket 25, and
for mounting the external float;ing shell 23 on the projec-
tion of the shell 8 durin~ assem~ly and disassembly opera-
tions.
T~e cross-sectional dimensions of the vertical surfaces
of the a~ove-mentioned shells 8 and 23 are formed such as
to ena~'le t~eir mutual displacement, as well as their contact
~ith, and displacement of, relative to the side surface of
the ingot liquid portion.
Other structural elements of this embodiment are simi-
lar to those described in the two previously mentioned em-
bodiments of the present invention.
The apparatus of the invention, shown in Fig. 3, operates
in the following manner.
Prior to starting the casting process, the bottom plate
7 is introduced into th,e zone of electromagnetic field of
the inductor 3, as descri~ed above in previous embodiments,
whereupon a coolant is fed onto the lateral surface of the
~ottom plate 7. The inductor 3 is then energized and a
required amount of coolant is delivered from the cooler 4.
Thereafter, the preheated internal shell 8 with the cover 9,
as well as the external shell 23 suspended during the assem-
bly oparation from the projection of the internal shell 8,
are mounted on the bracket 2S, so that the float gauge 14
is acco~odated in the opening of the ~racket 25. However,
it is important fox the lo~er portion of the external shell
23 to ~e clear o~ the solidif~ed front on the ingot lateral
surface~ The molten meta,l iS fed through the header 12
onto the botto~ plate 7 an~, with. the internal shell 8 being
im~ersed in the ,i~ngot melt surface, a melt of conducting
~7 -
'`'~b '
slag or degassing flux is fed onto the ingot upper horizon-
tal surface found within the confines of the internal shell
8. In addition, the internal shell 8 serves to prevent
various oxide, slag and other solid nonme-tallic inclusions
from getting to the peripheral area of the ingot liquid
portion, that is to the area of contact of the melt with the
external shell, which, floating on the surface of the ingot
liquid portion, protects the latter from oxidation and
immediate contact with the ambient gas atmosphere, which,
in turn, prevents the alloy highly volatile components from
escaping therefrom.
The floating external shell 23 shows immediate and
accurate response to an alteration in the level of the ingot
liquid zone. Such alterations are easy to determine visually,
as well as by means of any conventional control method, for example, by
the radioisotope method wherein a signal is sent to an actuating mechan~
ism operable b~ monitor the rate of metal consumption, or by the electro-
contact method effected by means of sending a signal to a magnetic valve.
The floating external shell 23 closes the greatest
part of the ingot liquid surface, thereby preventing the
alloy highly volatile components from escaping therefrom and
diminishing detrimental effect of the convective flows,
which, in turn, permits the alterations in the level of the
ingot zone to be easily controlled within the range of -2 mm.
Thus, the ingot produced from brass rich in zinc has
been tested to show sound crystalline structure, with the
surface thereof being free from flaws.
Shown in Fig, 4 is the preferred embodiment of the in-
vention. This embodiment of the apparatus ma~es it possible
to use a protectiVe melt or a rarefied atmosphere for effec-
tive protection of the entire surface of the ingot liquidportion. In addition, the ingot casting and sizing opera-
- 28 -
,
~3~6
tion are co~ined in thi~ app~ratus~
Referrin~ to its constructional aspect~ the apparatusof th~,s em~odiment also comprises a frame 1 whereupon are
mounted a baffle 2, inductor 3 and cooler 4. Mounted on
the ~affle 2 are two shells 8 and 26 with a cover 9. The
distinctive constructional feature of this embodiment lies
in the s~ell 26/ t~e intexiox dimensions of which make for
t~e gap to ~e formed at the upper section thereof between
its interior surface and the ingot lateral liquid surface;
a ring-shaped sizing ~and 27 being provided at the lower
section of the ingot forming zone. The opening area of the
sizing band 27 is shaped and sized in conformity with the
cross-sectional shape and size of the finished ingot 5.
Depending on the ingot-metal, the inter~or cross-sectional
dimensions of the upper portion of the external shell 26 are
selected to be 0.85 to 1.15 times the respective dimensions
of the sizing section or the band 27. The height of the
sizing band 27 constitutes 1/2 to 2/3 of the height of the
inductor 3. The lower end face of the external shell 26
is disposed belo~ the transverse axis of the inductor 3
within a distance of 1~4 to 2~3 of the height of the induc-
tor 3.
The side walls of the internal shell 8 are perforated
and are interconnected by means of a transverse perforated
partition 28. The wall o~ the external shell 26 is prefer-
ably formed with gating channels 29 intended for the supply
of metal therealong passing into the gap between the exter-
nal shell 26 and the side molten surface of the liquid por-
tion 6 of the in~ot 5 and having chemical composition dif-
ferent fro~ that of the ingot metal. The cover 9 and the
flange lQ of the intexnal shell 8 are formed with observa-
tion openings 21 intended fox visual control over the tech-
nologi~cal process~ The $hells 8 and 26 are provided with
adjusting scxe~s ll ena~l~ng said shells to be mounted in a
~ 29 ~
.
.
,~
preset positi~n, ~n the event of usin~ a flowing protective
~as at~os~here, the ~alls o the intexnal shell 8 are fo~m~
ed with openin~s 17 intended ~o~ the protective gas passed
along the tu~e 16 to flow therethroug~ into the interior
of the external shell 26~ To ~aintain a required intensity
o~ current and voltage on the Inductor 3, the latter is
provided with a regulator 30. The shell 26 has outlet open-
ings 22 intended for the discharge of the inert gas there-
throu~h.
The apparatus is operated in the following manner.
Prior to feeding molten metal, the bottom plate 7 is
introduced into the zone of electromagnetic field of the in-
ductor 3, so that the upper edge of the side surface there-
of is positioned 3 to lQ mm below t~e level of the trans-
verse axis of the inductor 3. The shell 26 is thence mount-
ed on the baffle 2. The gap ~etween the sizing band 27 of
the shell 26 and the side surface of the bottom plate 7 is
filled with a refractory mass. The inductor 3 is energized
and a coolant is supplied at a required flow rate, whereupon
the external shell 26 is heated to a temperature of 600 to
800C, Thereafter, the shell 8 in assembly with all its
elements, also preheated to a temperature of 600 to 800 C,
is mounted on the shell 26. Thence, a requisite protective
medium is provided, and a molten metal is fed to the ingot
electromagnetic forminy zone. After the molten metal por-
tion 6 is raised to achieve a preset level, determined
visually or by the readings of the metal level float gauge
14, an actuating mechanism is operated to lower the bottom
plate 7 ~ith the solidifying ingot. Then, if necessary, a
layer of degassing flux and~or conducting slag is superimpos-
ed on the in~ot molten surface.
~n the event of usin~ the proces-s and apparatus of the
invention for p~oducing an ~ngot, the surface of which is
~ 30 ~
..
~. ` ' .
~3~
coated ~ith a thin l~yer af metal having its chemical compo-
sition di~ferent ~rom t~at of the ingot metal, the melt of
this metal is fed throu~h t~e g~ting channels 29 to the
ingot forming elect~oma~netic æone disposed in the gap be-
t~een the ingot li~uid portion and the wall of the externalshell ~6.
As ~as been mentioned above, it is of great practical
significance to use the ingot contactless forming method
effected ~n electromagnetic ~ie:Ld and accompanied by immedi-
ate and intensi~e cooling of the ingot side surface, where-
by high-quality ingots are produced to be in conformity with
a prescribed profile and having uniform cross-section
throughaut its lengt~, with. the profile thereof ~eing differ-
ent from that of the ingot liquid portion.
Th.is o~jective is successfully attained in the appara-
tus of the invention for continuous casting of metal in
electromagnetic field, wherein the ingot-forming metal is
delivered in an amount sufficient for creating constant metal
static pressure with a value thereof being 5 to 20 per cent
above the rated value of the electromagnetic field compres-
sion pressure, and wherein the external shell 26, formed
~ith the sizing band ~7l is provided. Thus, as a result of
the hot plastic deformation to which is subjected the skin
of the solidifying ingot side surface, it becomes possible
to produce in~ots in strict conformity with a prescribed
size and shape thereof. Ry firmly squeezing the ingot skin,
a reliable tightening ~s provided, ~hereby the casting pro-
cess is carried out so that th.e entire surface of the ingotliquid portion is protected ~it~ an inert gas, conducting
slag and~or degassin~ ~lux, it also ~ecomes possibl~ to
provide a rarefied atmosphere a~ove the melt, and a layer
of metal, having chemical composition different from that
of the ~ngot met~l, around the latexal surface of the ingot
liquid portion,
. 31 -
,
:
~3~
It should be taken in~o account that the pressure force
re~uired to cause deformation of the ingot skin is insigni-
ficant, since the temperature of t~e ingot skin surface and
that of the sizing band 27 are practically equal.
The sizing action effected by means of the shell con-
tinues until the in~ot wall fiecomes strong enough to resist
to the pressure of the ingot liquid column. With the ex-
ternal shell 26 bein~ movable along the technological axis
of the apparatus, the position of the sizing band 27 of
this shell can be changed relative to the solidifying portion
of the ingot side surface, thereby permitting effective con-
trol to be carried out over the quality of the ingot sur-
face and over the accuracy of its cross-sectional dimensions.
After the inyot solidified portion has emeryed from the cool-
ing zone, the force of the metal static pressure is regulat-
ed by means of a metal consumption regulator or a molten
flux consumption regulator until it reaches a required per-
missible value which can be determined by effecting visual
control over the level of the ingot liquid portion or by
means of the metal level float gauge 14. This regulation of
the metal static pressure is undertaken with the purpose
of providing for more effective reducing action of the sizing
section 27 against the hot plastic skin of the ingot being
cast. The sizing section 27 of the external shell 26, the
upper portion of which remains clear of the ingot liquid
portion, acts upon the ingot skin radially towards the
ingot longitudinal axis above the level from which a cool-
ant is supplied to t~e surface of the solidified ingot at
the liquid-soli:d interface of its metal. The ingot forming
process effected under conditions of constant metal static
pressure being 5 to 2Q per cent in excess of the rated value
of the electromagnetic field compression pressure, is en-
sured by way of maintaining t~e level of the ingot liquid
portion above the rated level through the regulator intend-
ed for monitoring the flow rate of molten metal or that of
- 32 ~
3~
molten conductin~ sla~ and~or degassing .slag.
T~e r~ted value of the met~l static pressure of the melt
is equal to the value o the el~ectromagnetic field pressure
actin~ to support the column o~ molten metal in prescri~ed
cross-sectional dimensions over its height,
The production of sized ingots, with the cross-sectional
profile thereaf bein~ different from that of the inyot liquid
portion, is made possiBle due to the provision of an appro-
priately shaped and sized opening area of the sizing section
27 of the external shell 26, the profile and dimensions of
~hich are formed ~ith due regard to the extent of metal
shrinkage, taking place during the ingot solidification and
cooling processes,
Where it is required to carry out the continuous cast-
ing process in a flo~in~ protective gas atmosphere, the
walls of th.e external shell 26 are formed with through open-
ings 22.
It is possible for a rarefied atmosphere to be createdabove the surface of the liquid portion 6 of the ingot-5.
This being the case, the internal shell 8 is positioned in
a manner to have its perforated partition 28 arranged below
the level of the ingot molten metal, the through openings
22 in the external shell 26 being hermetically sealed.
The process according to the invention for continuous
casting of metal in electxomagnetic field is carried out so
that a coolant is at all times fed onto the solidified ingot,
preferabl~, a~tex sizing opera.tion~
The process and apparatus of the invention permitting
the production of high.~uality ingots from copper and alloys
thereof, that l's from all the metals and alloys suita~le for
~ 33
-
~,
3~
the production o~ ingots ~a~in~ great practical application.
`
::
~:~ 3Q
34 ~
- -
~ ~ .
- ' ' : .
