Improvements in Processes for Converting Cast Iron into Malleable Iron or Steel.
Year: 1894

page_text: Date of Application, 9th Aug., 1894
Complete Specification Left, 14th Mar., 1895-Accepted, 4th May, 1895
PROVISIONAL SPECIFICATION.
Improvements in Processes for Converting Cast Iron into Malleable
Iron or Steel.
We, SAMUEL HUFTY, of 46 North Third Street, in the City of Camden, State
of New Jersey, United States of America, Mechanical Engineer, and JOSEPH
KAY CALDWELL of 37 Tulpehocken Street in the City of Philadelphia State of
Pennsylvania United States of America Mechanical Engineer, do hereby declare
the nature of this invention to be as follows:-
The object of our invention is to effect the partial decarbonization of solid forms
of cast iron in order to convert the same into malleable iron or steel.
Our invention consists essentially of a process comprising two steps, first, the
bringing of the solid forms of cast iron to the required temperature by means of a
reducing flame, that is to say, a flame in which the oxygen is not much, if any, in
excess of the volume necessary to support combustion, and secondly, in bringing
into contact with the said solid forms of cast iron, after they have been properly
heated and while they are maintained at the desired temperature, a volume of
oxygen largely in excess of that required to support the combustion of the heating
flame, this excess of oxygen acting upon the highly heated carbon of the cast iron
to oxidize the same and thereby effect a partial elimination of the carbon from
the iron in the form of carbonic oxide, the treatment being continued until the
decarbonization of the iron to the desired extent has been effected. The desired
excess of oxygen is provided by means of jets of air or water preferably heated,
or by jets of steam, as hereinafter set forth.
A furnace adapted to use liquid hydrocarbon as fuel may be used, but coal,
wood, coke or other fuel may be used instead of liquid hydrocarbon, the hydro-
carbon being preferred however, on account of its greater convenience and
effectiveness.
An open hearth furnace may be used provided with suitable charging doors
and stack for the discharge of the products of combustion, the furnace being also
provided with a series of hydrocarbon burners of any available construction, but
preferably of that class in which the hydrocarbon is permitted to flow from a valved
pipe into a moving current of air, the volume and speed of which may be regulated
by means of a valve in the supply pipe, the hydrocarbon being atomized by the air
current and issuing with the same from the discharge nozzle of the burner so as to
act directly upon the solid forms of cast iron deposited upon the hearth of the
furnace.
Each hydrocarbon burner passes through a tuyere opening in the wall of the
furnace, which tuyere opening is closed at the outer end by means of a valved or
dampered register plate so that by properly adjusting the valve of said plate, air in
regulated volume may be permitted to flow through the tuyere opening or such flow
may be cut off, as desired."
In place, however, of such dampered tuyere plate, special pipes or nozzles,
may be used, these pipes or nozzles communicating with any available supply of
air under pressure and the flow of air through the said pipes or nozzles being
regulated by a suitable valve or series of valves, or, if desired, all of these different
means of supplying air to the interior of the furnace may be adopted in one and the

page_text: same structure, or instead of supplying air, the pipes or nozzles may supply jets of
water or steam, the water or air being by preference heated.
In carrying out our invention the solid forms of cast iron in the shape of pigs,
bars, ingots or moulded articles are deposited upon the hearth of the furnace and
the charging openings being closed, the flame from the burners is directed upon
the charge and is maintained until said charge becomes heated to the required
temperature, which should be several hundred degrees below the fusing temperature
of the metal.
While the heating of the charge is being effected all of the openings for
admitting air, steam or water to the hearth of the furnace are closed so that no
oxidization of the iron will be effected during the heating of the same, it being
understood that the flame from the burners is simply a reducing flame in which the
volume of exygen is not more than is sufficient to effect proper combustion of the
hydrocarbon element.
After the charge upon the hearth of the furnace has been heated to the required
degree and while the flame from the burners is still acting upon the charge in order
to maintain the heat of the same, the valves of the tuyere plates are opened, or air,
steam or water is forced into the furnace through the pipes or all of these sources
of supply are utilized for the purpose of directing volumes of oxygen into contact
with all parts of the heated charge from the hearth of the furnace, the air, steam
or water being decomposed on contact with the surfaces of the highly heated forms
of iron so as to set free the oxygen.
By thus introducing into the furnace oxygen largely in excess of the volume
needed to support the combustion of the hydrocarbon elements of the flame the
highly heated carbon of the iron is attacked and oxidized so as to pass off in the
form of carbonic oxide, experiment having demonstrated that when the iron is
heated to a temperature approaching the point of fusion the oxygen will have a
tendency to attack the carbon rather than the iron, as is evidenced by the fact that
in the practical carrying out of our process a considerable percentage of carbon
can be removed from the iron without any material formation of oxide of iron
scale upon the surfaces of the articles being treated, in fact, the formation of such
an oxide scale would be fatal to the proper carrying out of our invention, since the
scale acts in the nature of a seal and prevents access of the oxygen to the carbon
in the metal.
After the treatment has been continued for such a length of time as to effect the
decarbonization of the iron to the desired extent, the burners are shut off and the
flow of air to the furnace discontinued, the articles being allowed to cool slowly
until they are in condition to be removed preparatory to the introduction of a
fresh charge.
If a continuous flow of air, water or steam into the furnace in such volume and
with such force as to reach all portions of the charge contained therein, effects
any material reduction of the temperature of the charge, the flow may be stopped
at intervals until the flame from the burners again brings the charge up to the
desired temperature.
We are aware that it has been proposed to subject solid forms of cast iron upon
the hearth of a furnace to a flame containing carbon, hydrogen and oxygen in
quantity properly regulated to produce complete combustion and a homogeneous
flame previous to the admission of said flame to the furnace chamber, but our
invention differs essentially from this in that it involves the employment during the
oxidizing step of the process of oxygen in volume greatly in excess of that needed
to support combustion.
Dated this 9th day of August 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, Agents.

page_text: Improvements in Processes for Converting Cast Iron into Malleable
Iron or Steel.
We, SAMUEL HUFTY, of 46, North Third Street, in the City of Camden, State
of New Jersey, United States of America, Mechanical Engineer, and JOSEPH
KAY CALDWELL of 37 Tulpehocken Street, in the City of Philadelphia State of
Pennsylvania, United States of America, Mechanical Engineer, 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 our invention is to effect the partial decarbonization of solid forms
of cast iron in order to convert the same into malleable iron or steel, an object
which we attain in the manner hereinafter set forth, reference being had to the
accompanying drawing, in which-
Figure 1 represents a longitudinal sectional view of a furnace adapted for the
carrying out of our invention; and
Figure 2 represents a sectional plan view of the same.
Our invention consists essentially of a process comprising two steps, first, the
bringing of the solid forms of cast iron to the required temperature by means of a
reducing flame, that is to say, a flame in which the oxygen is not present in
volume necessary to cause complete combustion, and secondly, in bringing into
contact with the said solid forms of cast iron, after they have been properly heated
and while they are maintained at the desired temperature, by means of said reducing
flame, a volume of oxygen largely in excess of that required to support the
combustion of the heating flame, this excess of oxygen acting upon the highly heated
carbon of the cast iron to oxidise the same and thereby effect a partial elimination
of the carbon from the iron in the form of carbonic oxide, the treatment
being continued until the decarbonization of the iron to the desired extent has been
effected. The desired excess of oxygen is provided by means of jets of air or water,
preferably heated, or by jets of steam, as hereinafter set forth.
In the drawing we have illustrated a form of furnace adapted to use liquid
hydrocarbon as fuel, but it should be understood that coal, wood, coke or other fuel
may be used instead of liquid hydrocarbon without departing from our invention,
the hydrocarbon being preferred, however, on account of its greater convenience
and effectiveness.
A represents an open hearth furnace provided with suitable charging doors a and
stack for the discharge of the products of combustion, the furnace being also
provided with a series of hydrocarbon burners d of any available construction, but
preferably of that class in which the hydrocarbon is permitted to flow from a valved
pipe finto a moving current of air, the volume and speed of which may be regulated
by means of a valve g in the supply pipe, the hydrocarbon being atomized by the air
current and issuing with the same from the discharge nozzle of the burner so as to
act directly upon the solid forms of cast iron deposited upon the hearth of the
furnace.
Each hydrocarbon burner passes through a tuyere opening i in the wall of
the furnace, which tuyere opening is closed at the outer end by means of a valved or
dampered register plate m so that by properly adjusting the valve of the said plate,
air in regulated volume may be permitted to flow through the tuyere opening, or
such flow may be cut off, as desired.
In place, however, of such dampered tuyere plate, special pipes or nozzles, such for
instance as represented by dotted lines at n in Figure 2, or at n' in Figure 1, may
be used, these pipes or nozzles communicating with any available supply of air under
pressure and the flow of air through the said pipes or nozzles being regulated by a

page_text: suitable valve or series of valves, or, if desired, all of these different means of
supplying air to the interior of the furnace may be adopted in one and the same
structure, or instead of supplying air, the pipes or nozzles may supply jets of water
or steam, the water or air being by preference heated.
In carrying out our invention the solid forms of cast iron in the shape of
pigs, bars, ingots, or moulded articles are deposited upon the hearth of the
furnace and the charging openings being closed, the flame from the burners d is
directed upon the charge and is maintained until the said charge becomes heated to
the required temperature, which should be several hundred degrees below the fusing
temperature of the metal.
While the heating of the charge is being effected all of the openings for admitting
air, steam or water to the hearth of the furnace are closed so that no oxidiza-
tion of the iron will be effected during the heating of the same, it being understood
that the flame from the burners d is simply a reducing flame.
After the charge upon the hearth of the furnace has been heated to the required
degree and while the reducing flame from the burners d is still acting upon the
charge in order to maintain the heat of the same, the valves of the tuyere plates are
opened, or air, steam or water is forced into the furnace through the pipes nor n' or
ail of these sources of supply are utilized for the purpose of directing volumes of
oxygen into contact with all parts of the heated charge upon the hearth of the furnace,
the air, steam or water being decomposed on contact with the surfaces of the highly
heated forms of iron so as to set free the oxygen, which combines with the carbon
of the heated iron, and causes the same to pass off in the form of carbonic
oxide, experiment having demonstrated that when the iron is heated to a temperature
approaching the point of fusion the oxygen will have a tendency to attack the
carbon rather than the iron, as is evidenced by the fact that in the practical carrying
out of our process a considerable percentage of carbon can be removed from the iron
without any material formation of oxide of iron scale upon the surface of the articles
being treated, in fact, the formation of such an oxide scale would be fatal to the
proper carrying out of our invention, since the scale acts in the nature of a seal and
prevents access of the oxygen to the carbon in the metal.
After the treatment has been continued for such a length of time as to effect the
decarbonization of the iron to the desired extent, the burners dare shut off and the
flow of air to the furnace discontinued, the articles being allowed to cool slowly
until they are in condition to be removed preparatory to the introduction of a fresh
charge.
If a continuous flow of air, water or steam into the furnace in such volume
and with such force as to reach all portions of the charge contained therein, effects any
material reduction of the temperature of the charge, the flow may be stopped at
intervals until the flame from the burners d again brings the charge up to the
desired temperature.
We are aware that it has been proposed to subject solid forms of cast iron upon
the hearth of a furnace to a flame containing carbon, hydrogen and oxygen
in quantity properly regulated to produce complete combustion and a homogeneous
flame previous to the admission of the said flame to the furnace chamber, but our
invention differs essentially from this in that it involves the employment of a
reducing flame for heating and while the said reducing flame is still maintained, the
bringing into contact with the heated iron of a decomposible oxygen-bearing fluid,
which by its decomposition supplies the oxygen necessary to attack and remove
carbon from the iron.
Having now particularly described. and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
The mode herein described of treating solid forms of cast iron for the
converting the same into malleable iron or steel, the said process consisting in first
purpose of
heating the said articles in an open hearth furnace by reducing flame to a

page_text: temperature somewhat below the point of fusion, and, after the iron has reached the
desired temperature, and while it is still subjected to the action of the said reducing
flame, bringing into direct contact with the iron, a decomposible oxygen-bearing
fluid in such volume, that by its decomposition, oxygen is freed in volume
sufficient to combine with and eliminate carbon from the heated iron, substantially
as specified.
Dated this 14th dox of March 1805
JOHNSONS & WILLCOX,
Agents.