Process for Forming Ingots.
Year: 1891

page_text: Date of Application, 6th Jan., 1891-Accepted, 18th Apr., 1891
COMPLETE SPECIFICATION.
Process for Forming Ingots.
I, WILLIAM RUSSELL HINSDALE, a resident of No. 800, Broad Street, in the
City of Newark, County of Essex, and State of New Jersey, United States of
America, Engineer, do hereby declare the nature of my invention for PROCESS
FOR FORMING INGOTS, and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
In the formation of cast steel ingots especially those containing a large proportion
of carbon, it is common for the shrinkage of the metal when poured in an ingot
mold, to form a cavity or cavities in the upper end of the ingot, and, if such cavity
be exposed to the atmosphere, its walls become speedily oxidized, and in that
condition, are incapable of welding closely together.
Such oxidation is especially liable to happen where the ingots are stored for some
time before using, as the atmosphere in such case, has a longer period in which to
act upon the surface of the cavity, and the lack of union between the adjacent
surfaces of the cavity, when the ingot is rolled into a merchant bar, commonly
causes a serious defect therein.
The object of the present invention is to protect any cavities that may be formed
within the ingot from the atmosphere, during the cooling and shrinking period; by
hermetically sealing such cavities, so that, when formed, the ingot may be stored
for any length of time before using without exposing such cavities to oxidation.
When steel ingots are cast in an open mold, a crust of chilled metal is formed at
the mouth of the mold before any material shrinkage cavity occurs; but when a
shrinkage cavity is formed beneath such open mouth, the contraction and resulting
vacuum causes the breakage of such crust, and the admission of the atmosphere to
the cavity.
In my invention the shrinkage cavity is not allowed to form beneath such a thin
crust, but is caused to form in a part of the ingot previously chilled in such degree,
that the skin cannot be ruptured by interior contraction or atmospheric pressure.
The invention consists in first chilling the top of the casting to exclude the
atmosphere, and in then turning the ingot, before its interior is solidified, into such
position that the shrinkage cavity shall occur in contact with a chilled portion of
the surface having sufficient strength to resist the strains caused by internal
contraction and the consequent atmospheric pressure.
The chilling of the metal at the mouth of the mold, and subsequent reversing of
the mold before the shrinkage occurs sufficiently to rupture the chilled surface,
causes the formation of a cavity at the end of the mold opposite to its mouth,
which, by inversion, has become the top, where it is fully protected from the
atmosphere by the previous chilling of the surface metal, and can never be exposed
to oxidation.
The invention also includes a particular method for controlling the formation of
the shrinkage cavity within a stud or projection at one end of the ingot, and so
proportioned that the shrinkage cavity may be separated from the ingot with very
little of the hardened metal.
It also consists in sometimes placing a heated cup of refractory material like fire
brick, within the bottom of the mold, before pouring the fluid metal therein, to
prevent the metal first poured into the mold from hardening too rapidly, and in
then inverting the mold.
By retaining the metal fluid in the bottom of the mold and then reversing the
mold, the formation of a cavity within that extreme end of the ingot at the bottom
end of the mold, is greatly facilitated; as the metal, excepting the mere surface
portion, after the reversal of the mold, then flows readily downward from the

page_text: inverted bottom of the mold and permits any confined gases to rise into the
inverted cup, and determines the formation, within the cup, of any cavity caused by
shrinkage.
The invention is shown herein applied to a crucible mold and to a Bessemer
mold, Fig. 1 of the drawing showing a Bessemer mold in vertical section on
line, r, in Fig. 2, and Fig. 2 being a section of the same on line y, 7, in Fig. 1.
Fig. 3 is a view of the top end of the Bessemer mold with cap applied. Fig. 4 is a
side view of the Bessemer mold reversed; Figs. 5 and 6 represent in side view and
plan, the cup for the Bessemer mold. Fig. 7 represents a crucible mold parted at
its longitudinal joint with the bands and the contents of the mold in vertical section
on line 2, , in Fig. 8. Fig. 8 is a plan of the mold ready for pouring; Fig. 9 is a
plan of the bottom cup for the crucible mold; and Fig. 10 a section of the same on
line a, e, in Fig. 5. Fig. 1 is a vertical section transverse to the view shown in
Fig. 3, of a crucible mold reversed.
a is a Bessemer mold made in one piece with tapering bore, and provided with a
base connected with the mold by lugs c and keys d inserted in studs d'.
A cap is shown secured upon the mold by a rod inserted in eyes h; and
trunnions e are provided upon the sides of the mold to suspend the same by a bail .
A tapering hole j is formed through the base, and a cup k, formed of fire brick
material, is fitted in such hole serving to close the bottom of the mold, and at the
same time to receive a small portion of its contents.
and some wet or moist sand s
The mold a is shown filled with fluid metal
applied to the surface of the metal beneath the cap f.
The process of using such a mold is as follows.
The mouth of the mold, where the capfis applied, being open, the cup k is
heated to redness and dropped in the hole in the base b.
The mold is filled nearly to the top with fluid metal 1, the sand s is then placed
upon the top of such metal to chill the same, and the cover inserted in the
mouth of the mold and locked in place by passing the rod g through the eyes h.
The bail is then lifted by suitable means, to suspend the mold upon the
trunnions e, and the mold is then turned with the mouth downward and the base
upward, as shown in Fig. 4.
The contact of the sand s with the top of the metal operates to chill the surface
thereof, and to quickly form a skin over the top of the ingot to retain the molten
metal, and all the remaining surface of the ingot in contact with the walls of the
mold is similarly chilled. In like manner, the cup k although it may be heated, is
cooler than the fluid metal, and the metal in the cup k being first poured, therefore
becomes exteriorly chilled before the mold is reversed.
When the metal in the mold is cooled in a reversed position, any shrinkage
cavity formed within the mold in the upper end of the ingot is fully protected from
oxidation by the skin or crust of chilled metal.
The cup k for the Bessemer mold is shown detached in Figs. 5 and 6, and is made
of tapering form to fit it easily within the aperture j in the base, and to permit of
its ready removal.
In Figs. 7 to 11 is shown the means for practising the invention with crucible
steel molds, which are adapted commonly to hold from eighty to ninety pounds of
steel, the contents of a single crucible. Such molds are shown formed in
longitudinal halves a¹ rebated together as at a2 in Fig. 8, and held together during
the casting operation by bands m and keys n.
The mold is shown with trunnions e formed upon the opposite halves a', and the
cup k is shown of suitable dimensions to drop within the bore of the mold, and with
rounded bottom to fit the rounded form of the bottom commonly used in such
molds.
Such cup could be readily dropped in the mold from the top, when heated, and
serves an additional function in protecting the bottom of the mold from cutting
when the metal is poured therein, which cutting injures the quality of the steel in
the bottom of the ingot, by the admixture of cast iron.

page_text: In operating with so small a quantity of metal as the contents of one crucible,
very little precaution is required to hold the metal within the mold when reversed,
as the surface of the metal, at the mouth of the mold, readily chills when the
pouring is completed, and forms a skin adapted to prevent the leakage of the metal
when the mold is inverted.
In Fig. 7, the cap is shown secured in the mold by a wedge f¹, but in Fig. 11
the mold is shown filled to its mouth, above the fluid metal, with damp or wet sand
to chill the surface of the metal, which suffices to hold the metal in the mold when
reversed, as shown in said figure.
It is obvious that after the reversal of the mold, while its contents are fluid, the
cooling continues with the usual feeding downward of the fluid center to supply the
shrinkage in the lower part of the ingot, leaving in the inverted mold a sealed
cavity with bright surface which may be either removed or welded up, as
desired.
Fig. 11 shows a hollow cavity or pipe p formed within the cup k by such reversal,
and enclosed within a skin or shell of hardened metal in contact with the interior of
the cup.
By proportioning the internal capacity of the cup to the volume of shrinkage in
the ingot, the portion of the ingot contained within the cup might be almost wholly
filled by a shrinkage cavity, so that when the ingot was cooled, the removal of the
projecting part, formed in the cup, would remove the entire pipe from the ingot and
leave its body entirely sound. Figs. 9 and 10 show a cup with its mouth k¹ slightly
contracted, and the edges of the cup k² around the mouth, beveled inward, so as to
prevent the spattering of the metal on the walls of the mold, and to form a
contracted neck at the junction, with the ingot, of the portion cast within
the cup.
Such construction greatly facilitates the breaking off from the ingot of the
portion formed in the cup, and leaves the end of the ingot in substantially the same
shape as if it were cast in a round-bottom mold.
My invention may be practised by the removal of the casting from the mold
before its reversal as it is very common, while the interior of an ingot remains fluid,
to remove the mold therefrom to promote its cooling.
Such removal could not be effected unless the shell of the ingot were sufficiently
chilled to bear handling and retain its form; and it is obvious that, when the ingot
is in this condition it may be readily reversed with the bottom end upward, and
that the shrinkage cavity formed therein would occur adjacent to the former bottom
of the ingot where the crust is much thicker than at the top end (which was last
poured into the mold).
Such thick crust will not be liable to rupture under the pressure of the
atmosphere or the internal contraction of the metal in cooling, which rupture
generally occurs when the shrinkage cavity is formed at the hot upper end of the
ingot.
Such castings are preferably placed when reversed, with their former upper ends
in contact with a bed of sand, to prevent any "bleeding" of the ingot in case the
heated metal should remelt the thin crust formed at the top of the ingot. With
previous methods the end of an ingot in which a pipe is formed is defective when
formed into a bar, and a portion of the bar varying from ten to fifteen per cent. is
invariably cut off to remove the defective portion.
By the present invention the cavity does not become oxidized, and when the
ingot is rolled into a bar the sides of the cavities become perfectly welded and no
defect is caused in the product.
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:
⚫ ---
1st. The process of forming ingots which consists first, in forming the casting in
an ingot mold. secondly, protecting the top of the casting from the atmosphere by

page_text: chilling the same, and, thirdly, reversing the casting, as and for the purpose set
forth.
2nd. The process of forming ingots which consists first, in filling the ingot mold,
secondly, in excluding the atmosphere from the mouth of the mold by a cap, and
thirdly, reversing the mold, as and for the purpose set forth.
3rd. The process of forming ingots which consists first, in inserting a cup of
heated material in the bottom of the mold, secondly, filling the mold, and thirdly,
reversing the mold, as and for the purpose set forth.
Dated this 6th day of January 1891.
S. S. BROMHEAD,
97, Newgate Street, London, E.C., Patent Agent.