Improvements in Steel Founding.
Year: 1894

page_text: Date of Application (in United Kingdom), 6th Feb., 1894
Complete Specification Left, 6th Feb., 1894-Accepted, 14th Apr.,
1894
Improvements in Steel Founding.
I, JAMES GLASS MC ROBERTS, of 1522, La Salle Street, St. Louis, Missouri,
United States of America, Steel Founder, do hereby declare the nature of my
invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
Between steel founding and ordinary iron founding this important difference exists
in practice; about twice as much heat is required in steel founding as is in iron
founding, and in consequence shrinkage-strains to a corresponding degree have to be
provided for. Furthermore, in view of the excessive heat referred to, it has been the
practice to employ dry sand molds exclusively. The steam and gases created by the
highly heated steel in casting it are generated so rapidly and profusely as to hitherto
preclude the use of green sand molds. But in the employment of dry sand molds
this difficulty encountered the parts of a dry sand mold are incapable of
yielding, or yielding sufficiently, to the steel as it contracts in cooling, and in
consequence of this many forms cannot be cast. For instance, a structure of a
U-shape in cross-section cannot be made satisfactorily; for the various sides in
cooling draw toward each other and, meeting the resistive dry sand, are liable to,
and frequently do, check and crack. Any form also having a shoulder projecting
in a direction more or less crosswise to that in which the shrinkage occurs is liable
to rupture at or in the vicinity of the shoulder. As shapes such as referred to
represent a large class of structures which it is desirable to form out of steel it is
apparent that as the art of steel founding now exists the use of cast steel is
materially limited. Moreover the expense of steel founding is considerably
increased in having to use dry sand molds.
To prevent the checking and rupturing referred to it has been customary to
reinforce the casting, at the points therein where the shrinkage-strains have to
be met, by forming upon the casting fins, brackets, and projections variously
shaped according to the particular shape of casting being made. The integrity of
the casting in this manner can often be preserved but the reinforce in question has
to be removed from the casting after it has been made. Owing to the extreme
toughness of the steel the removal is an expensive operation, so expensive as to
frequently make it undesirable to make the casting.
The improvement under consideration possesses several advantages some of which
are as follows: Wooden instead of iron flasks can be used; drying-ovens as well
as the means for transferring the flasks to and from the ovens, are dispensed with,
and the cost of operating the ovens obviated; that space upon the foundry floor
which is required for carriages for the dry sand molds is saved for other purposes;
but a single handling of the mold after it is made is required; the proportion of
casting lost by checking is largely if not entirely diminished; and the loss arising
from falling out due to excessive handling is prevented; the reinforces are no
longer needed except in quite exceptional instances, and the time employed in

page_text: molding them in is saved; the loss arising from the burning and destruction of
molds in the drying-oven, something liable to occur, is prevented, and the cost of
drying the mold is avoided, but further, and more especially, the improvement is
desirable in that it greatly extends the use of cast steel, and in that it materially
cheapens the operation of steel founding.
The invention consists partly in the improved method of casting the steel, and
partly in the apparatus employed in carrying out the method, all substantially as is
hereinafter set forth and claimed, aided by the annexed drawings, making part of
this Specification, in which-
Figure 1 is a horizontal section of a suitable molding apparatus; duplicate
castings are arranged to be made and the view includes special cores for the special
castings being made.
Fig. 2 a vertical section on the line 2-2 of Fig. 1 ;
Fig. 3 a vertical section of a modified molding apparatus ;
Fig. 4 a vertical section of another modified molding apparatus;
Figs. 5 and 6 respectively a side elevation and a plan of a structure to the casting
of which the improvement is adapted, and which is employed to illustrate the
operation of the improvement;
Fig. 7 a horizontal section on the line 7-7 of Fig. 9, of a molding apparatus
constructed according to the principle of the improvement, and specially adapted
for casting the structure shown in Figs. 5 and 6; only a portion of the apparatus
is shown;
Fig. 8 a vertical section on the line 8-8 of Fig. 7; and
Fig. 9 a vertical section on the line 9-9 of Fig. 7.
The same letters of reference denote the same parts.
In carrying out the method under consideration the casting is made in a substan-
tially green sand chamber or mold, but the molten lead is introduced into said
chamber or mold through a substantially dry sand runner or gate. I say substan-
tially, for while an entirely green-sand inold, and an entirely dry-sand runner may
be, and in most instances are, employed and are preferred, it is possible to have a
portion or portions of the mold-walis of dry sand where such dry portions do not
offer resistance to the shrinkage of the metal in cooling to cause a rupture in the
casting, and also to have a portion or portions of the runner of green sand if they
do not occur where, the molten metal in being introduced into the mold would
abrade or break away the gate or mold and thereby frustrate the formation of the
casting but for such dry portion or portions. It is also necessary, in cases where a
core is required, and the molten current enters the mold and impinges as a stream
upon it, to have the core a dry sand one. What however characterizes the method
is the introduction of the metal by such means and in such a manner as to prevent
particles of foreign matter, such as the particles of the wall of the gate through
which the metal is poured, from being carried with the metal into the meld, and as
to prevent the generating of steam or gas either to break up the molten current and
unfavorably affect the casting in respect to solidity, or to act to splinter off portions
of the gate to be borne along into the mold, and, on the other hand, the making
of the casting so that it shall be free to contract in cooling and when made to be
integral.
An additional characteristic is introducing the molten metal into and through
the mold so that it shall not break away or abrade any opposing part of the mold
walls, and so that it shall dry-skin the mold walls in advance of its progress into the
mold and enable the steam generated in such skin-drying to be vented without
interfering with the metal or casting. Accordingly I prepare a wet sand mold of
the desired shape and I introduce the steel thereinto by pouring it downward
through a gate whose descending portion, including a bottom-portion at the lower
end of said descending portion, and upon which the metal drops, is of dry sand, and
from said bottom-portion conduct the metal horizontally, or horizontally and
upward, or substantially horizontally, or substantially horizontally and upward,
into the mold, and in delivering the metal into the mold it is not allowed to

page_text: drop as a body downward so as to cause the metal to bore into the bottom
of the mold, but it is delivered either sidewise or upward into the mold. The
mold is vented freely (many more vents being employed than are in iron
casting) and as the metal flows into and upward and fills the mold its heat
however fast the metal may flow, skin-dries the inner surface of the mold in
advance of the progress of the metal, and as a result the moisture and gases.
generated in the mold are enabled to escape without interfering with the metal or
the casting, and the casting at the same time is formed within a mold having the
yielding property of the ordinary wet sand mold, and in consequence the castings
as a rule are perfectly made.
The described process may be illustrated by reference to the annexed drawings.
The mold, A, Figs. 1 and 2, represents one adapted for the casting of a pair of
draw-bars B and B¹.
The gate is shown at C. It has the descending portion c, the bottom c¹ beneath
the descending portion, and the branches, c², c², and cs, es, which connect with the
descending portion c and lead thence, two of them, c, c², to the chamber for casting
the draw-bar B, and two of them, c³, c, to the chamber for casting the draw bar B₁.
D and D represent dry sand cores suitably constructed and arranged for the
special work in question. The descending portion of the core is of dry sand as is
also the bottom portion . The mold is of wet sand. The metal is poured
downward through the gate-portion and it flows thence through the various
passages, c, c, into the chambers for forming the draw-bars, and as it enters said
chambers it encounters the dry sand cores and it flows thence throughout the
chambers and the castings are thereby made. Owing to the gate-portions c, and c¹
being of dry sand the metal does not generate any steam therein, nor does it cut or
bore into that portion of the gate which is underneath the portion c. And even if
the horizontal portions of the gate, the ones containing the passages e² and c³, were
of wet sand such passages would by reason of the heat of the metal be skin-dried in
advance of the movement of the metal. The dry sand cores, D, D¹, receive the
shock of the inflowing metal and are not abraded thereby. The metal after being
cast cools without restraint and although there are various shoulders, b, b¹, b², &c.,
upon the draw bar no rupture or check occurs at those points owing to the yielding
nature of the mold.
Fig. 3 illustrates an arrangement where the metal is introduced through a horn-
gate E, or a gate shaped to enable the metal, after dropping to the lowest part of
the gate, to rise into the chamber F of the mold. Provision for a riser is shown
at f. The chamber F, in the present instance is for making a casting having no
shoulders, and the view is introduced more especially to illustrate the horn-gate, the
gate having the descending portion e and the bottom portion e', and from such
bottom portion the gate, in extending it to meet the chamber F, may be of wet sand
but is preferably of dry sand like the portions e and e¹ of the gate. For the metal
after reaching the bottom of the gate acts to skin-dry the descending portion, e², of
the gate and expel the moisture thereof in manner similar to that in which the.
interior surface of the mold is skin-dried.
Fig. 4 illustrates an arrangement where the metal is delivered through a gate G
sidewise into the mold H. A core is shown. The core is of dry sand, the mold
is of wet sand, and the gate, at least the descending portion y and the bottom
portion thereof, is of dry sand.
Figs. 5 and 6 are respectively a side and a top view of a car truck bolster to be
cast according to the method under consideration. Said bolster in cross-section is
of an inverted U-shape, having the top J, the sides J', J, and the ends J³, J³, and
the bolster is otherwise shaped substantially as shown.
The bolster is cast in a mold K, Figs. 7, 8 and 9. L represents the gate to be
used in connection with said mold. It has the descending portion I, the bottom l',
and passages 12, 12, connect the gate-portion with the mold. Said last named
passages 12, 12, connect with the mold at an end thereof, and in depth the passages
are equal to the depth of the bolster-sides respectively, and connect therewith
.
.

page_text: substantially as shown. The metal is poured downward through the gate to fall upon
the bottom thereof and it flows thence through the passages 12 12, and entering the
mold flows throughout the length and height thereof. For the sake of insuring
the sharply-defined corners, m, m, in constructing the column-guides, M, of the
bolster, special cores, N, N, are employed. While made tougher than the material
of an ordinary wet sand mold they are not unyielding as a dry sand core is, and
thus they may be considered, in respect to the yielding quality of the mold,
homogeneous therewith. The gate, L, so far as the descending and bottom
portions thereof are concerned, is substantially of dry sand. The mold K is sub-
stantially of wet sand, and the above described advantages of a dry sand gate and
a wet sand mold are, as in the case of the forms shown in Figs. 1, 3 and 4 obtained
in the casting of the bolster.
The illustrations here given will answer for any other structures more or less
analogous in form to those shown.
In using the terms "dry sand" and "wet sand" 1 desire not to be restricted to
sand specifically, but wish it understood that any suitable equivalents may be
substituted therefor respectively; that is, in the one case, refractory material
suitable for making a gate through which molten steel can be poured downward
without abrading the gate, or generating steam to cause what is termed explosion
in the metal, and, in the other case, material suitable for forming a mold of the
yielding nature described, may be used.
It is possible in the case of a quite shallow casting, and where an interposed core
may be used, to arrange the mold immediately beneath the gate instead of at the
side thereof.
Irrespective of any special method or means for introducing the metal into the
mold a steel casting made in a wet sand mold as described is superior to a steel
casting, made in a dry sand mold. A steel casting made in a dry sand mold has to
be shaken out right away as otherwise it cannot be saved. But when made in a
wet sand mold the casting can, and it is my practice to allow it to remain in the
mold for several hours, and, indeed, for an indefinite time, and by reason of this
the casting is notably tougher than is a casting made from the same metal in a dry
sand mold. The casting in cooling off thus slowly in its own sand becomes
measurably annealed.
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 herein described improvement in the art of steel founding the same
consisting in introducing the steel through a dry sand gate and forming the casting
in a wet sand mold, as set forth.
2. The herein described improvement in the art of founding steel the same con-
sisting in introducing the steel through a dry sand gate into and throughout a green
sand mold, and so that the heat of the molten steel shall skin-dry the mold-walls in
advance of the progress of the metal through the mold.
Dated this 15th day of January 1894.
JAMES GLASS MCROBERTS.
Day, Davies, & Hunt,
321, High Holborn, London, W.C., Agents for the Applicant.