Improvements in Casting Metal Rolls or Cylinders.
Year: 1897

page_text: Date of Application, 5th Jan., 1897-Accepted, 6th Mar., 1897
COMPLETE SPECIFICATION.
Improvements in Casting Metal Rolls or Cylinders.
I, JOHN LESTER LEWIS, Manufacturer, residing at No. 136 Craig Street, in
Pittsburg, in the County of Allegheny, State of Pennsylvania, and 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 invention described herein relates to certain improvements in casting chilled
rolls having plain or ungrooved surfaces. As is well known among roll mauu-
facturers, it is nearly impossible to obtain at all times a uniform depth of chill at
all points on the roll surface. It is also well known that almost as soon as the
fluid metal comes into contact with the inner wall of the chill, the metal is solidified
forming a thin shell, while the metal within the shell remains liquid for a con-
siderable time. The contraction which occurs on the formation of the thin shell
of chilled iron draws the latter out of immediate contact with the mold chill so
that such shell is subjected to considerable internal pressure due to the liquid
column of metal, while nearly or entirely unsupported externally. This internal
pressure against the unsupported shell frequently produces longitudinal cracks in
the roll, rendering the latter useless except for scrap.
The object of the present invention is to provide for the maintenance of the
cooling and solidifying metal in such position within the mold that all points on
the surface of the roll shall be equi-distant from the internal wall of the chill of
the mold, or that the solidifying metal shall be held in such relation to the chill
of the mold that an approximately uniform depth of chill may be obtained at all
points. It is a further object of the invention to provide a series of circum-
ferential supports for the solidifying metal, until such time as it is relieved
from the internal pressure of the liquid column, or in other words until such
time as the chilled shell shall have become strong enough by cooling to resist
the fluid pressure within. The invention is hereinafter more fully described and
claimed.
In the accompanying drawings forming a part of this specification,
Figure 1 is a section of elevation showing the usual form of mold employed in
casting rolls with the latter in position in the mold.
Fig. 2 is a similar view having my improvements applied thereto.
Figs. 3, 4, 5, 6 and 7 are sectional elevations of chills illustrating different forms
or means for the carrying out of my improvements.
As shown in Fig. 1, the mold now in general use consists of the cylindrical
chill 1, the cope and drag 2 and 3, and the spout 4 which is connected to the drag
as shown. The cope and drag 2 and 3 contain, when prepared for casting, the
dried loam sand in which the journals and coupling ends of the rolls are formed.
I have found that when a mold of the character or construction above described
is filled with metal and the latter begins to contract during cooling and solidifica-
tion, that the roll will frequently take an inclined position, that is, it will lean
against the chill of the mold on one side and consequently will be separated from
I

page_text: it at other points. Wherever the roll remains in contact with the chill of the
mold by reason of the bending or inclination of the roll body, the depth of chill
may be considerable, while at those points which are not in contact, the depth of
the chill will be less, such shallowness of chill being proportioned to the distance
. between the surface of the roll and the internal wall of the chill. It frequently
occurs that the roll in cooling and contracting will change its position one or more
times, hence there will be one or more points having a considerable depth of chill,
and a corresponding number of points having lesser depth of chill.
In order to overcome this inequality of chill, I provide for the maintenance of
the roll centrally within the chill of the mold during cooling and solidification, so
that all points on the surface of the roll will be equi-distant from the inner wall of
the chill of the mold. This centralization of the roll may be effected in different
ways, as, for example, the chill of the mold may be so constructed as to be
provided with a series of downwardly beveled or inclined shoulders which will
bear upon correspondingly inclined shoulders formed on the roll during casting.
During cooling and solidification the roll contracts longitudinally and diametrically
and as the longitudinal contraction will necessarily produce a sinking or downward
movement of the roll in the chill of the mold, the inclined shoulders on the roll
and chill of the mold will bear upon each other and hold the roll centrally within
the chill of the mold. As the inclined shoulders on the chill of the mold and ou
the roll are in contact with each other, the thin shell first formed by the' contact
of the liquid metal with the inner wall of the chill of the mold' will have ample
external support to prevent rupture by the internal pressure. The inclination or
bevel of these shoulders should be such as will not interfere with the natural" or
necessary movement of the roll due to contraction, or in other words, care should
be taken to prevent the roll hanging on the shoulders, as in such case the roll
might be liable to be torn apart or otherwise injured.
'
1.In the construction shown in Figs. 2 and 3, one, two, or more grooves 5 are
formed in the inner wall of the chill of the mold and the lower edges of these
grooves are beveled or inclined downwardly, forming slioulders 6. When the
metal is poured in the mold, one or more circumferential bands or a number of
such projections 7. as may be provided for, will be formed upon the roll "body,
having their lower edges inclined as shown at 8. As the metal contracts in cooling
and solidification the bands or projections 7 will be gradually drawn out from the
annular grooves or recesses in the chill of the mold and the settling down of the
roll in the mold will cause the shoulders 8 on the roll to move along the corre
spondingly inclined shoulders 6 on the chill, thereby maintaining the roll centrally
within the chill...
'
111
As shown in Fig. 4 a band or circumferential projection 9 may be formed on the
inner wall of the chill of the mold, said projection having its upper edge inclined
as at 10 This-circular projection will form a recess in the roll with its upper
edge beveled or inclined corresponding to the inclination of the shoulder 10. As
the metal contracts and the roll settles or moves longitudinally in 'the mold,
e.downward, the same centralizing action will occur as in the construction shown
in Figs. 2 and 3.
1
1.
!
1.
In lieu of providing continuous shoulders on the inner wall of the chill of the
mold as shown in Figs. 2, 3, and 4, a series of independent shoulders 12 may be
provided. As shown in Fig. 5, these shoulders 12 are formed by cutting notches 13'
in the inner wall of the chill of the mold and suitably beveling the lower edges
thereof. In Fig. 6, the shoulders 12 are formed by cutting or drilling conical
cavities 14 having flat bottoms in the wall of the chill of the mold: In Fig. 7 a
suitably beveled or inclined shoulder 15 is formed at the upper end of the chill of
the mold by beveling the mouth of same in the manner shown.
.:
It will be readily understood by those skilled in the art that the recessing,
notching. or
or cutting away of portions of the wall of the chill of the mold will
result in the production of shoulders or projections on the roll, such shoulders' ör'
p.1.

page_text: projections having bevels or inclines corresponding to similar bevels or inclines in
the recesses, grooves, or cavities in the chill of the mold.
Care should be taken that the shoulders on the chill of the mold should be so
proportioned as to height or their outstanding from the surface of the wall of
said chill that the shoulders on the roll will be in contact therewith during con-
traction, due to solidification, but when such contraction has ceased such shoulders
will not prevent the removal of the chill of the mold from the roll by stripping or
lifting it off the roll by the trunnions 16 formed on the outer sides of the chill of
the mold.
It will be readily understood by those skilled in the art that the shoulders or
grooves which are formed on or in the rolls during casting are comparatively slight
and being temporary, are removed when the rolls are turned, so that such shoulders
or grooves are not to be confounded with the collars or grooves finally formed on
or in rolls for reducing billets, rods, etc. And by the phrase "plain-faced rolls,"
as used in the following claims, I refer to the roll body in its cylindrical state
after the temporary projections or depressions, as the case may be, are removed in
the ordinary turning operation.
It is characteristic of the preferred means for the practice of the invention
described herein, that advantage is taken of the movement or sinking down of the
metal due to contraction, to hold the roll in the desired relation to the wall of the
chill of the mold, and also to maintain an external support for the thin shell of
chilled iron.
I do not wish to limit myself herein to any particular means or construction
whereby the roll is maintained or forced into a central position within the chill of
the mold as I consider it within the scope of my invention to employ any suitable
means for effecting such an equalization of distance of the roll from the walls of
the chill of the mold as will result in an equalization of the depth of the chill at
all points in the roll.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The method of preserving or maintaining the centrality of a cylindrical
casting while cooling in the mold by making slight elevations (or equivalent
depressions) on or in the face of the casting which by the shrinking of the casting
during cooling, will be reduced in radial direction at least to the radial diameter
of the mold cavity, substantially as set forth.
2. The combination of a mold for casting ungrooved or plain faced rolls, and
means adapted to bear against the roll for maintaining the roll centrally within
the mold, so that the axes of the mold and roll will substantially coincide during
the cooling and solidification of the roll, substantially as set forth.
3. The combination of a mold for casting ungrooved or plain faced rolls and
means caused to bear against the roll by the movement of the latter due to its
contraction during cooling and solidification and thereby maintain the roll centrally
within the mold with its axis in practical coincidence with the axis of the mold,
substantially as set forth.
4. In a mold for casting plain faced rolls, one or more shallow shoulders con-
tinuous or interrupted as may be preferred, made in or on the face of the mold
cavity, and proportioned with reference to the expected shrinkage of the casting
during cooling, substantially as described, whereby to preserve exactly or
approximately the centrality of the casting during such cooling.
5. A mold having in combination therewith a chill provided on its inner wall
with a downwardly inclined or beveled shoulder whereby the roll will be main-
tained in a central position in the mold and supported externally during cooling
and solidification.
6. A mold having in combination therewith a chill provided with one or more

page_text: annular recesses having their lower edges downwardly inclined or beveled, whereby
the roll will be maintained in a central position in the mold and supported
externally during cooling and solidification.
Dated at Pittsburg, Pa.. U.S.A.. this Twenty-fourth day of November