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Патент USA US2116483

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May 3, 1938.
c. E. WILLIAMS ET AL
2,1 16,483
Filed Dec. 19,‘ 1934
‘
‘
'
I VENTORS
c/yalye E. W‘//
I la075.
C/arence hf L or,
BY 5;
7'ATTORNEYS.
W7
2,116,483
Patented May 3, 1938
' UNITED STATES
PATENT OFFICE
2,116,483
MOLD
Clyde E. VVilllams and Gamma Lorig, C0iumbus, Ohio, assignors to The Battelle Me
mortal Institute, Columbus, Ohio, as corpora
tion of Ohio
Application December 19, 1934‘, Serial No. 758,275
1 Claim.- (01. 22-139.)
Our invention relates to molds. It has’ to do portion of the mold facilitates, to a certain extent,
particularly with molds for casting steel, iron,
aluminum, or other metals and which are espe
cially applicable to the casting of ingots, although
5 it is not necessarily limited thereto.
'
In the prior art of casting ingots from such
materials as steel, aluminum, copper, or other
metals, it has been customary to use molds all
parts of which were composed of iron or steel and
10 being of a shape or form consistent with the pro
» duction of ingots of a shape or form most readily
adapted to subsequent fabrication, forging and
rolling operations. Although the use of such cast
iron or steel molds is practically universal in the
15 steel industry, in the casting of steel ingots, these
cast iron or steel molds have serious limitations
and disadvantages which arise chie?y from the
inherent properties of the material from which
they are made.
'
'
In the past, big-end-up molds have usually
been made from cast iron and in a single piece.
It has been found that such molds are subject to
the removal of the ingot from the mold. How
ever, it has been'found that many times the lower
'end of the ingot will weld to the cast iron stool
and cannot be removed therefrom without di?ie
culty and without disastrous results to either the
ingot or the‘ mold stool.
In pouring the metal into ingot molds having
an integral cast iron bottom or a separate cast
iron stool, due to the comparatively low thermal
conductivity of a cast iron bottom, the metal in‘
the lower portion of the mold does not cool as
quickly as desirable, which permits 01’ the spread
ingof the oxides, formed during the initial pour
ing action, upwardly through the ingot to an un
desirable extent thereby lowering the quality of ~
the ingot. 'It is desirable to bring about fairly
'quick cooling and solidi?cation of a thin layer at
the lower end of the ingot with a consequent en
trapment of the oxides in this layer, so that the 20
portion subsequently cropped from the lower end
of the ingot contains practically all of the oxides
formed'during the initial pouring action.
It is also desirable to bring about the initial
rapid cooling of the lower layer, because this 25
greatly minimizes the splashing tendency with its
consequent formation of cold shuts, scabs, etc.
an excessive amount of thermal cracking. Dur
ing use of the mold, the constant expansion and
as contraction forces set up by heating and cooling
of the mold, since the mold is made in one piece,
causes cracking around the bottom.
Such molds also do not satisfactorly resist the In order to reduce the amount of necessary crop
cutting action caused by metal being poured into pingof the lower end of the ingot and the tend
,0 them. It is not uncommon for the bottoms of cast ency of splashing of the metal during the initial
iron molds to be severely cut away upon pouring pouring action, a depression has been provided in
the ?rst ingots into them. Though the molds are' the bottom of the mold'r'or in the stool thereof.
not scrapped immediately when the ?rst signs of This depression or concavity serves as a con
cutting appear, they do produce ingots which must tinuation of the mold cavity so that immediately
when the pouring action is initiated, a pool of
be cropped at the bottom more extensively to re
move the defects caused by the imperfect molds metal is formed which greatly minimizes the
which are cut. Many cast iron molds are splashing of the metal during the pouring opera
screwed even before thermal cracks have made tion. This also produces a convexity on the lower
them useless, due to the fact that they have been end of the ingot which reduces the amount of
‘0 severely cut by the pouring of the metal therein. cropping necessary. The depression in the bot
Big-end-down molds have usually been made of tom of the mold is of a predetermined size and
shape. However, since the bottom of the mold
cast iron and have embodied a body portion hav
is made of cast iron, when the metal is poured
ing an open lower end which is closed by a sep
arable cast iron stool. Since the stool is made of into contact with the cast iron bottom, due to the
cutting action of the metal thereon, the contour
“ 45 cast iron,~it does not resist the cutting action pro
of this depression will be completely destroyed
duced by pouring of the metal in the molds. Con
sequently, the mold stools will only last a short after one or a few pouring operations. ‘
The cutting of the bottom of the cast iron mold
time and in many cases will be severely cut the
or of the cast iron mold stool caused by the pour
‘ first time they are used. Another disadvantage
5b of cast iron molds resides in the fact that the - ing of the metal, produces cavities therein which
cast iron is of such a character that the ingot become successively deeper with each pouring op
In addition to destroying the uniform
metal poured therein willtend to weldto any eration.
contour
of
the lower end of the ingot, this forma
cutaway portion of the mold. Thus, it is di?icult
to remove the ingot from the mold. The fact that tion of cavities is accompanied by a welding of
55 the stool is made separate from the main body the ingot to the bottom or stool, so that this inter
30
35
40
45
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2,116,483 '
?tting and more or less welded condition greatly
increases the difficulty of stripping and ‘sometimes
makes it impossible without pulling away certain
portions of the ingot or pulling away certain por
tions of the stool.
Another disadvantage encountered in the use
of a mold embodying a cast iron body portion and
a cast iron stool, is the comparatively large size
of the fin which forms when a portion of the
initially poured molten metal runs into any open
space between the stool and the side walls of the
mold. Due to the low thermal conductivity of
the cast iron, the ?n metal is comparatively
slowly chilled and consequently the size of the ?n
15 will be greater than if the ?n metal chilled more
rapidly. The fin metal tends to break the mold
side walls during stripping and the larger its area
the more danger there is of breakage of the mold.
One of the objects of our invention is to pro
20 vide a mold for casting ingots which is of such a
nature that the ingots which are produced will be
of the highest quality.
‘ Another object of our invention is to provide a
mold which comprises a main body portion and
a separable stool member, the stool member being
of such a nature that the metal stream will not
tend to cut the surface thereof when it impinges
thereagainst and the ingot will not weld thereto.
Another object of our invention is to provide
a mold for casting ingots whereby during the
initial pouring'operation, the oxides formed in
the lower‘ layer of the ingot will be entrapped in
this layer and will be prevented from spreading
upwardly through the ingot to an undesirable
extent.
Another object of our invention is to provide
a mold or stool or both of such a nature that the
splashing tendency of the metal being poured
will be greatly minimized.
-
Another object of our invention is to provide
amold or stool or both of such a nature that the
cutting of the mold or stool and the consequent
splashing of the material thereof followed by the
contamination of the ingot by such material will
45 be obviated.
Another object of this invention is to provide
entrapment of the oxides in this layer. Conse—
quently, that portion subsequently cropped from
the lower end of the ingot contains practically
all of the oxides formed during the initial pour
ing action, as distinguished from the slower initial
cooling which results when the metal is poured
upon cast iron which permits’ of the spreading of
the oxides upwardly through the ingot to a much
greater extent.
,
A further advantage of this method arises from 10
the fact that neither the stool nor the mold will
be cut away and that, therefore, all danger of
contamination of the ingot by the material of
the mold or stool will be eliminated.
Thus, one
of the disadvantages ‘characteristic of cast iron
molds or stools is obviated.
Furthermore, the initial rapid cooling which
thus results from the pouring of the metal into
contact withla surface of copper greatly mini
mizes the splashing tendency with its consequent
formation of cold shuts, scabs, etc. This advan
tageous result is further materially enhanced by
the use of a depression in the stool which com
municates with the mold cavity and which imme~
diately brings about a chilling of a local pool of 25
the metal and greatly’ minimizes the splashing of
the metal during the pouring operation.
In
other words, the use of a copper or copper alloy
stool having a concavity formed therein results
in an extension of the mold cavity so that the
pouring of the molten metal into this concavity
produces a rapidly cooled projecting lower end
for the ingot with a consequent localizing of the
undesirable oxides in this relatively small portion
of the ingot, which portion is to be ultimately
cropped.
With this method the lower portion of the ingot
is quickly cooled because of the copper or copper
alloy stool. However, since we contemplate mak
ing the side walls of cast iron which has a com
paratively low thermal‘ conductivity, the portion
of the ingot above the thin layer which is quickly
cooled will cool at a rate slower than the rate
at which said thin layer was cooled. Consequent
ly, the rate of cooling of the outer side walls of
the ingot will be su?‘iciently slow to avoid crack
a mold for ingots which will have a longer life ing of the ingot.
than the cast iron or steel molds now in use.
A further advantage of the use of a copper or
We preferably provide a mold of such a nature 7 copper alloy stool arises from the fact that the
50 that the molten metal poured therein initially
rapid chilling of the lower end of the ingot creates 50
contacts with a metal portion. thereof which is
a condition which facilitates stripping. Thus, in
of relatively high heat conductivity and then as . a big-end-down mold, the rapid chilling, setting,
the pouring operation is continued, the molten and increased contraction of the lower end of the
metal contacts with a metal portion of the mold ingot, in conjunction with the continued expan
which is of relatively low heat conductivity. We sion of the lower side wall of the mold, creates a
preferably use a mold which embodies a body greater air gap and facilitates the separation of
portion composed of cast iron which has both the ingot and the mold.
ends open and the lower end of which is closed
Likewise, with a big-end-up mold, the use of
by a stool member composed of copper or copper .
a copper or copper alloy stool in combination with
alloy. The stool which we preferably use is of a main body portion of cast iron, results in‘ an
pure copper. However, it may be of other copper important decrease in the size of any ?n, which 60
or of copper alloy, though it is desirable that it forms when a portion of the initially poured
be of such a nature that it will have a thermal
conductivity at least as high as sixty ?ve per cent
65 of the conductivity of pure copper.
The metal preferably is poured from a substan
tial height into contact with the surface of the
copper or copper alloy stool member which pref
- erably supports and closesv the lower end of the
cavity in the mold. This copper or copper alloy
stool member is of such cross-section that it is
self-cooling and, owing to- its relatively great
heat conducting capacity, it immediately brings
about a cooling and solidi?cation of a thin layer
75 at the lower end of the ingot with a consequent
molten metal runs into any open space between
the stool and the side walls. When a copper or
copper alloy stool is used, this ?n metal, as well
as a thin layer within the mold cavity, is quickly
chilled. Moreover, this chilling takes place be
fore there can be any material expansion of the
cast iron side walls. Since the ?n metal is thus
quickly chilled, its position and its size are ?xed 70
and determined. Subsequent expansion of the
mold side walls takes place in a direction away
from the ingot and from the ?n, while, coinciden
tally, the ingot shrinks or contracts and undoubt
edly causes some contraction of the ?n metal. 75
3
2,116,488
One result of this is that the fin metal overlap
ping the end of the mold side walls at the time
,of stripping is less than would be the case where
of the ingot which will be subsequently neces
sary.
a convex lower end on an ingot, in order to re
a cast iron base or stool is used and, consequently,
where the ?n metal does not chill as rapidly.
Since the ?n metal tends to break the mold side
15
20
25
30
duce the amount of necessary cropping, by the
use of cast iron molds having the lower ends of
walls, during stripping, any decrease of bearing
the cavities formed therein of a shape similar
forming our method are shown in the accom
characteristics, is its high thermal conductivity,
its relatively high melting temperature and heat
capacity and its toughness at all temperatures
below its melting point. Its thermal characteris
tics give it the necessary properties to resist the
area or size of the tin on the end of the mold side 'to- that shown in Figure l and of a predeter
walls'tends to minimize breakage of the mold. . mined size. However, when metal is poured into
both because of decreased leverage and thinner such a cast iron mold, due to the cutting action
thereof, the contour of the cavity in the bottom
?n metal towards its outer periphery.
'
Another advantage of the use of a copper or or stool of the mold will be materially altered.
copper alloy bottom or stool for the mold arises However, if the mold bottom or stool is made of
from the obviation for a much longer period of copper or copper alloy, the molten metal poured 15
use of cavities which, in a cast iron bottom or therein will not cut the’ bottom or stool and will
stool,’ are formed by the pouring of metals and not destroy the contour thereof, at least, for a
long period of time? Thus, an ingot with a con- ‘
which become successively deeper with each pour
ing operation. In addition to destroying the vex lower end of predetermined shape and size
‘
uniform contour of the‘ lower end of the ingots,‘ may be produced.
The upper end of the concavity l in the mold 20
this formation of cavities is accompanied by a
welding of the ingot to the bottom, so that this stool is slightly smaller in diameter than the ,
inter?tting and more or less welded condition lower end of the mold cavity 2. Thus the edge
greatly increases the di?iculty of stripping and of the cavity 4 will be spaced a slight distance
sometimes makes it impossible without pulling from the inner surface of the side wall of the 25
away certain portions of the ingot or pulling body portion I. Therefore, when the molten
metal is initially poured into the mold, splashing
away certain portions of the stool.
This application is a continuation in part of against the side walls of the mold will be mate
our application on Molds, Serial No. 698,456, ?ied rially decreased.
Certain inherent physical characteristics of 30
November 17, 1933.
.
.
copper or copper alloys make them an excellent
Illustrative embodiments of molds made in ac
material for mold stools. Principal among these
cordance with our invention and used in per
panying drawing wherein:
Figure l is a vertical section of a mold of the
35 big-end-up type and embodyingv a main body
portion of cast iron with a separable stool of
cutting action of the molten metal.
This has been demonstrated in plant tests
where many hundred ingots have been poured on
copper or copper alloy closing the open lower
end thereof, the stool member being provided
40
'
In the past, it has been attempted to produce
with a concavity in its upper surface.
Figure 2 is a vertical section of a mold similar
to that of Figure 1, means being provided for
preventing displacement of the body portion of
the mold relative to the mold stool.
Figure 3 is a vertical section of a big-end-up
45 mold embodying a cast iron body“ portion “and a
copper or copper alloy stool, the concavity in the
upper surface of the stool being eliminated in
this instance.
‘
‘
.
r
.
Figure 4 is a vertical section of a big-end-down
50 mold embodying a body portion of cast iron and
a separable copper or copper alloy stool.
Figure 5 is a vertical section of a mold ‘em
bodying a body portion of cast iron and a sep
arable stool of copper or copper alloy, the stool
55 having a cavity in both its upper and lower
surfaces.
In Figure 1, we show a mold which is of the
a copper stool without once having an ingot weld 40
to the stool. On the other hand, cast iron stools
usually weld or fuse to the ingots cast upon them.
Due to the cutting and fusing of the cast iron
stools to the metal ingots, the normal life oi’ such
stools is approximately '75 heats. In contrast to 45
the short life of cast iron mold stools, a copper
mold stool of identical design has now been used
for casting 1200 ingots. On the basis of per
formance to date, it is estimated that the stool
will have a life in excess of 1200 pourings, or, at 50
least, 16 times that of cast iron stools.
As previously mentioned,- big-end-up molds
have usually been cast in one piece and have
thereby been subject to excessive cracking es
pecially at the bottom thereof. The majority of 55
the bottom thermal cracks are in areas where in
tense expansion or contraction stresses develop
big-‘end-up type. This mold comprises a main during teeming and subsequent cooling of the
body portion l which is preferably madeof cast . steel in the molds. The separation or the big 60
60 iron.~ This body portion has amoid cavity 2 end-up molds into a cast iron body portion and
formed therein which .is open at both its upper a stool member of copper or copper alloy extends
and lower ends. A stool member 3 is provided the life of the mold.
for supporting the body portion l and for clos- ..
ing the lower end of the mold cavity 2. This
65 stool member 3‘ will be of copperor copper alloy
and will be of suiiicient cross-sectional area and
mass ‘to eiIect rapid cooling of the lower end,
of the ingot. Since the body portion i of the‘
mold is made of cast iron,‘ the upper portion of
'
the ingot will be cooled at‘a slower rate.
The upper surface of the mold stool I is pro
vided with a concavity 4. This concavity 4
serves as a continuation of the mold cavity 2 and
is of a predetermined size and shape in order to
75 reduce the amount of cropping of the lower end
In Figure 2, we show a big-end-up' mold simi
lar to that shown in Figure 1. In this instance,
the body portion 5 is made of cast iron and the 65
mold stool 6 is made of copper or copper alloy. ,
The stool member 8 has a concavity ‘I formed in
the upper surface thereof. However, in this in-,
stance, the copper mold stool is provided with a
shoulder which cooperates with a corresponding 70
cutout portion 9 in'the lower edge of the body
portion 5 of the mold, to maintain the body por
tion centered relative to the stool member.
In Figure 3, we show a mold of the big-end-up
type which embodies a cast iron body portion ii 75
4
2,1 16,488
‘and a separable stool member I l of copper or cop
per alloy. However, in this instance, the con
cavity in the upper surface of the mold stool is
eliminated.
The stools of the big-end-up molds require no
bottom hole or opening common to all big-end-up
molds of today in order to facilitate the removal
of the ingot from the mold. The ingot will not
Figure 1, and is- provided for the same purposes.
The mold stool l5 should be fairly thick. We
provide a stool with a double/concavity so that
the stool can be turned over after it has been used
a very long time, thereby extending the life of it.
It will be understood from the above descrip
tion that we have provided a mold for casting
metals which has many desirable features. As
readily weld to the copper or copper alloy stool. brought out in the preceding description, by
10' and, should it stick to the upper part of the mold,
making the mold of a cast iron body portion and
the ingot with said upper part may be lifted from the mold stool of copper or copper alloy, many
the stool and the ingot ejected by means common ’ desirable results are obtained. It is important
in shop practice. However, it will be understood to have the mold stool made of material having a
that plugs may be used if desired.
higher thermal conductivity than the metal of
Our invention is not limited ‘to making molds of the body portion of the mold.
the big-end-up type with copper or copper alloy
By the term "copper”, used in the following
stools. Thus, in Figure 4, we show a big-end
claim, we also intend to cover copper alloys.
down mold which comprises a main body portion
Having thus describedour invention, what we
I2 which is preferably of cast iron. The mold claim is:
~stoo1 IS on which the body portion l2 rests is
A mold for casting iron or steel ingots com
composed of copper or copper alloy.
prising a body portion composed of cast iron and
. The mold stool I3 may also be provided with
having a mold cavity formed therein, and a base
a concavity in its upper surface which. is similar for closing the lower end of said mold cavity, said
to the concavity 4, of Figure 1, in order to mini
base being composed of copper, said copper base
mize splashing, and to avoid excessive cropping, being of such a size that it will extend outwardly
as explained previously. '
past the inner surface of the wall of the mold cav
In Figure 5, we show a mold embodying a cast
ity and having its upper surface exposed so that
iron body portion I4 and a separable stool mem
metal poured into the mold cavity will contact
ber I5 of copper or copper alloy. In this in
with said surface.
stance, however, the stool member has a concavity
CLYDE E. WILLIAMS.
16, formed both in its upper surface and its lower
CLARENCE H. LORIG.
surface, which is similar to the concavity 1% of
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