Casting Metals.
Year: 1886

page_text: Casting Metals.
I, JOHN R. WHITNEY of Radnor Township Delaware County, State of Penn-
sylvania in the United States of America do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
The object of my invention is to secure chilled car wheels of uniform circum-
ference although cast from metal of varying tempers, perfect in roundness, chilled
to uniform depth in all parts of the tread and free from pimples and blotches at
the root of the flange. These objects I effect by casting the wheels against chills
of practically uniform density throughout, and so constructed as to contract in
diameter by the action of the heat of the molten metal alone, as fully set forth
hereinafter. Wheels cast in chills so constructed are not so liable to be affected
by differences in the temper of the metal as in chills of the ordinary construction.
My invention further consists in constructing the chill and combining it with the
drag and cope as fully set forth hereinafter, and as illustrated in the accompanying
drawing, in which:
Fig. 1 is a sectional plan of an improved chill constructed in accordance with
my invention.
Fig. 2 is a vertical section of a flask showing the arrangement of the chill
therein.
Fig. 3 is a side view of the chill.
Fig. 4 is a plan of the chill commonly used.
Fig. 5 is a transverse section of the chill shown in Fig. 4.
Fig. 6 is a portion of the plan of a chill with sections separated by saw kerfs.
Ordinary car wheel chills as heretofore made, have consisted of solid rings of
metal of about one and a half inches in thickness and sometimes more, and
provided upon opposite sides with trunnions or handles as shown in Figs. 4 and 5.
At other times the chills have consisted of rings to which are bolted an inner
facing or lining composed of separate pieces in close proximity. In other cases
the chill has consisted of a hollow ring with radial and vertical sections which are
made to expand and contract by alternate currents of water and steam through,
the hollow ring.
:

page_text: In the ordinary chills above named the parts constituting the chilling surface
are of different thicknesses at different points in the circumference, and owing to
this and other features of the construction, the density of the metal varies at
different points of the chilling surface. Thus in a chill of an inch and a half
in thickness, as illustrated in Figs. 4 and 5, the central portion is always much
more open than the outer edges, and this inequality of texture is increased at
intervals wherever there are projections, such as are formed by the trunnions a,
and lugs b. As a consequence when the molten metal is poured into the mould
the chill does not expand equally at all points and so remains in contact with the
wheel longer at some points than at others, and thus produces a deeper chill
wherever the contact is most prolonged. This effect is increased if the flask is out
of level or the chill is unequally exposed to currents of air etc.
This unequal and irregular expansion of the chill is very apt to result in perma-
nently altering its original shape, so that the wheels produced in it after a time
become more or less out of round. As the inner surface of the ring is first heated
and tends to expand before the outer portion can yield, the said inner surface also
soon becomes disintegrated and loses its original sinoothness of finish.
Another difficulty resulting from the employment of chills of the ordinary con-
struction ensues from the fact that if the molten metal is of a soft, fluid, low chilling
character, it retains its heat much longer than when harder and chilling well. It
thus expands the chill to a much larger size before the enclosed wheel becomes
solid and as a consequence wheels made from metals of different tempers even if
cast in chills of the same diameter when cold, will be found to vary in circum-
ferenco.
All these difficulties I overcome partly by the use of a chill of a particular form,
and partly by constructing the chill whatever may be its form, so that all parts of
the chilling surface shall be of the same or nearly the same density, for I have dis-
covered that when the chilling surface is of uniform or nearly uniform density, the
chill produced is more likely to be of uniform depth, and this discovery has enabled
me to secure uniform results by a proper construction of the chill.
One means of making the chill so as to secure the uniform 'or nearly uniform
density of the chilling surface consists in constructing it of parts substantially
uniform and not exceeding one inch in thickness and preferably very much less, SO
that when cast there will be no undue strains tending to condense some parts more
than others. Thus instead of making the chill in the form of a ring of one and a
balf inches or more in thickness, and with projections at some portions, as illus-
trated in Figs. 4 and 5, I construct the chill with two rings A, B, each of about
five eighths or three fourths of an inch in thickness connected by webs, the inner
ring B being of uniform thickness throughout its entire extent while the webs c
which connect the inner to the outer ring, are no thicker than the inner ring,
I have found by actual experiment that a chilling surface of five eighths of an inch
thickness is amply sufficient to produce deep and uniform chills on the wheel if
kept in contact with the tread thereof until solid. This uniformity in the thickness
of the rings and webs insures a practical uniformity of density in the chilling
surface of the ring B. The outer ring A, is preferably made of the same thickness
and entirely without trunnions or lugs, so that when the chill is heated all the
parts will expand simultaneously and regularly.
-
To increase the efficiency of the inner ring B, it is separated into sections by
narrow slots or kerfs s, extending radially into the openings y between the 'webs c,
so that each section is free to expand when heated by the molten metal of the
enclosed wheel without its surface being compressed, while the expansion of all the
sections and their supporting webs causes the contraction of the inner diameter of
the chill, and keeps the chilling surface in close and equal contact with the wheel
at all points as long as the chilling effects are needed.
While the inner ring is thus kept in contact with the wheel the outer ring can
be maintained in a nearly cool condition, so as to maintain the general shape and
dimensions of the chill, by the natural passage of 'air' through the openings', across

page_text: the narrow webs c, the chill projecting beyond the cope and drag so that air.
can flow freely to and upward through and from said openings outside of the cope
and drag. Heretofore when the inner face of the chill has been divided by radial
slots, the latter have been made by means of saws or other thin cutting tools. This
involves great expense of tools and labor and requires that the sections should be
comparatively thin at the points where thus cut, as shown at e Fig. 6. But being
thinner at these points than at others, produces a chilling surface of varying
thickness. This cannot be avoided so long as the slits must be formed after the
chill is cast, but I have discovered that the chill may be made complete with the
slits between the sections by arranging thin sheets of asbestos in the mould, so as
to separate the metal in the process of casting, the asbestos forming cores much
thinner than the smallest kerf than can be cut by saws or other tools available for
such purposes or that can be made by strips of iron or other material used as cores.
By this means I am enabled to separate the sections by spaces not exceeding one
one-hundredth part of an inch in width, if required, thus allowing room for the
requisite expansion of the sections and consequent contraction of the chill, and yet
preventing any irregularities in the casting from this cause.
The arrangement of the chill in respect to the drag T and cope C is illustrated
in Fig. 2, where it will be seen that the parts occupy such relative positions
that the air can pass freely and naturally upward through the openings y, thus
preserving the outer ring at such a low temperature as to prevent the alteration in
the form and dimensions of the chill which would otherwise occur.
When the molten metal is brought in contact with the ordinary chill, it is found
that it begins to heat the same and expand it,.but as soon as the metal solidifies it
also itself expands so as to remain in contact with the chill until the solidification
of the surface is complete, after which it immediately begins to contract, whilst
the chill itself, if constructed as usual, continues to expand. If the chill is con-
structed in the ordinary manner a constantly increasing separation between the
wheel and the chill thus takos place, but in the construction of the chill above
described, the outer ring A remains cold and does not expand, but the heating of
the ring B, and the webs c, causes the expansion of these parts and the sections
of the ring are moved inward, thus maintaining the chilling surface in contact
with the metal until the latter has become thoroughly hardened and deeply chilled.
The chill thus constructed may be used in connection with a suitable sprinkling
apparatus, whereby the effects above described are much increased. But whether
the sprinkling apparatus be used or the natural draft of the air alone be depended
upon for keeping the outer ring of the chill at a low temperature, the effect is to
produce wheels of substantially uniform circumference, regardless of the temper of
the metal, inasmuch as the variations in the length of time with which the metal is
in contact with the chilling surface, can have no effect in changing the size of the
outer ring which serves as a fixed abutment from which the sections of the ring
may expand, and thus contract the inner diameter of the chill.
In order to permit the chill to be readily lifted, I prefer to provide the outer
ring with a flange d, which extends completely around the periphery, but which
does not materially affect the density of the chilling surface of the inner ring or
section of the chill. This flange serves as a means of seizing the chill by the.
grapples when it has to be moved and has the further advantage of permitting the
chill to be easily rolled from place to place which cannot be done when it is provided
with trunnions.
The slots s may be vertical or they may extend diagonally, in which case the
webs c should also be diagonal or the webs may be horizontal, supporting annular
sections divided by horizontal slots. The other forms of chill to which reference
has been made cannot be made in one casting, they are much more complicated in
their parts and more costly to produce, operate, and maintain than those above
described.
.
I do not here claim the manufacture of slotted chills by the use of thin blades
or cores of refractory material, as this forms the subject of separate application for
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page_text: "
Letters Patent, and although I have specially referred to chills for making car
wheels my invention is applicable to chills for casting various other objects such as
chilled rolls, ploughs etc.
I do not limit myself to the precise construction and arrangement of parts
shown, but having now particularly described and ascertained the nature of the
said invention, and in what manner the same is to be performed, I declare that
what I claim is :-
1. A chill consisting of an outer and an inner ring or plate, the latter being
divided into segments or sections by the process of casting, and the segments
connected by webs with the outer ring or plate, all the parts being of such
thickness as to be of equal or nearly equal density throughout, and all forming
together one complete and undivided casting, substantially as set forth.
2. A chill consisting of an outer ring, an inner ring or plate divided into sections
of uniform thickness throughout, and of one or more connecting webs between
each inner section and the outer ring all formed in one complete casting, substan-
tially as set forth.
3. A chill consisting of a solid continuous casting with its chilling surface
separated into segments or sections by the process of casting, and having air
passages whereby the heat alone of the molten metal poured into the chill will
cause its inner diameter to contract while the air prevents the expansion of its
outer diameter, substantially as set forth.
4. A chill, consisting of an outer ring, an inner ring, composed of a series of
sections of uniform density, and connecting webs, all forming one complete casting,
substantially as set forth.
5. A chill, consisting of an outer and an inner ring and connecting webs, the
outer ring having an unobstructed circular periphery, for the purpose described.
6. A chill provided with an outer ring, and an inner ring composed of sections
supported by webs, with intervening slots, less than one sixteenth of an inch in
width, all formed in one complete casting, for the purposed described.
7. The combination in a moulding flask of a cope, drag, and of a chill, consisting
of an inner and an outer ring, connected by webs arranged to form openings y,
arranged to permit upward drafts of air to pass without artificial or mechanical aid
of any kind, substantially as set forth.
8. The combination of the cope, drag, and the chill, having vertical openings.
between its inner and outer rings, arranged with the said openings beyond the
outer faces of the cope and drag, substantially as and for the purposes described.
Dated this 17th day of November 1886