IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1873

page_text: LETTERS PATENT to Benjamin Joseph Barnard Mills, of the Firm of
Harris and Mills, of 35, Southampton Buildings, in the County of
Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF IRON AND STEEL."-A communication from abroad
by Charles Burgess, of Portsmouth, in the County of Scioto, and
State of Ohio, United States of America, Iron and Steel Manu-
facturer.
PROVISIONAL SPECIFICATION left by the said Benjamin Joseph
Barnard Mills at the Office of the Commissioners of Patents, with
his Petition, on the 4th November 1878.
I, BENJAMIN JOSEPH BARNARD MILLS, of the Firm of Harris and
5 Mills, of 35, Southampton Buildings, in the County of Middlesex,
Patent Agent, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL," a communication
to me from abroad by Charles Burgess, of Portsmouth, in the County of

page_text: Scioto, and State of Ohio, United States of America, Iron and Steel
Manufacturer, to be follows:-
:-
This Invention relates in part to the fining or partial refining of cast
iron by the use of mineral coal in an ordinary puddling, or gas, or other
suitable closed or reverberatory furnace or any furnace which may be
adapted for the carrying out of the process as herein-after set fortn.
The Invention further relates to a rapid, economical, and effective
process for the manufacture of steel direct from cast iron in a common
puddling or other suitable furnace, by a continuation of or addition to
the same process by which fined cast iron is produced as herein-after
explained.
The Invention further relates to the production of a composite iron
for use in the production of chilled and other castings, by the mixture
of fined cast iron with soft gray cast iron as herein-after explained.
In carrying out the Invention a common reverberatory furnace with
sunken hearth may be employed. A fire which may be of ordinary coal
having been raised in the fire-place of a puddling furnace or other
suitable closed or reverberatory furnace, a charge of broken pig or other
cast iron is placed on the hearth, and the ash-pit and damper being left
open so as to secure a thorough draft, the workman examines the charge
from time to time through the stopper hole, and as soon as the exposed
upper surface shows signs of partial fusion the workman gently turns
over the pieces so as to expose fresh surfaces to the action of the flame,
after which he keeps shifting the pieces until they are all melted down
into the condition of a "puddle." The workman then (the ash-pit and
the damper remaining open) closes the stopper hole and stimulates the
fire. This process of intense heating and active combustion without
manipulation of any sort is permitted to continue for a period of five to
fifteen minutes or longer, according to the quantity and quality of the
metal until the workman closely watching the behaviour of the charge
from time to time through the stopper hole observes, first, at that
portion of the metal near the fire-bridge numerous jets of blue flame
about the size of the flame of an ordinary tallow candle. The tap hole
is then opened so as to allow the charge to flow out into a suitable
shallow cast iron mould, such as customarily employed in the moulding
of refinery metal, and the crust of cinder separated by the application
of cold water in the usual way. Iron thus refined may be used with

page_text: great advantage and a large saving of expense in casting, and in the
manufacture of malleable iron. It is well adapted for the manufacture
of bells by reason of its clearness. It may be remelted in a cupola for
casting, or it may be reworked in the puddling furnace or knobbling
fire or charcoal fire in any customary manner for producing wrought
iron
Casting, of it may be reworked in the puddling furnace or knobbling
fire or charcoal fire in any customary manner for producing wrought
iron
It will be manifest that in carrying out the process the reverberatory
furnace may be arranged to take the molten metal direct from the
smelting furnace.
To hasten the refining process and at the same time effect a saving in
fuel tuyeres may be introduced through the side or sidos, or end or ends
of the refining hearth (whichever is most convenient), the said tuyeres
being so arranged as to carry a pressure of air or a blast into the body of
the molten metal. The hearth of the furnace being charged with raw pig
iron or cast iron, and the charge fused in the usual way by the heat and
flame passing over it from the fire-grate, the blast is turned on by
opening stop valves in the blast pipe. The atmospheric air being thus
forced into the body of molten iron the oxygen comes in contact with
the carbon and quickly raises an intense heat in the metal and increases
the heat of the furnace. The blast may be checked from time to
time so as to enable the workman to observe when the metal is
sufficiently refined, which is known by the swelling and rising of the
mass, and by the appearance of small bluish flames produced by the
combination of jets of gas escaping from the molten mass, at which time
the metal is tapped out into suitable moulds.
By the introduction of a blast into the molten iron not only is the
refining operation quickened, but a large quantity can be refined at one
charge and a great saving in fuel is effected, the combustion of the
carbon by the contact of air furnishing the heat. By thus introducing
a blast into the furnace hearth where the metal is taken directly from the
hearth of the smelting furnace or blast furnace, the fire-grate may be
dispensed with entirely by the following means :-Fire is placed on the
refining hearth, the blast opened, and fuel added. The hearth soon
acquires an intense heat; the fuel may then be withdrawn from the
refining hearth with an iron rake or scraper, and the metal allowed to
flow from the smelting furnace on to the hearth of the hot refining
furnace. The charge of crude metal being in the refining furnace the

page_text: blast is applied, and air forced into the body of molten metal as before
explained. The combustion of carbon and other matter soon produces
an intense heat in the metal and in the furnace, and carries the refining
operation to any desired extent, the mass being tapped out when it is
observed to swell or rise and as soon as the blue jets appear.
The hearth of the refining furnace, which is thus used in connection
with the melting furnace, is similar to the hearth of a puddling furnace
with a covered or arched top, the necessary door or doors and the stopper
hole through which the workman watches the behaviour of the charge
of metal and observes the proper time to tap out. The introduction of
the molten metal directly from the cupola or smelting furnace saves the
fuel otherwise required to remelt it, and unless too long a time is allowed
to elapse between the charges the use of fuel in the refining furnace
may be dispensed with entirely after the first heating. The quality of
refined cast iron produced by the customary refining process in the
refinery fire is known by the clearness it exhibits when broken, and by a
rough or honeycombed surface. The quality indicated by the honey-
combed surface is obtained by the lengthened time of blowing the blast
into the molten metal.
In the improved process if more honeycombed surface be desired the
metal is not tapped out as soon as it swells up or jets of blue flame
appear, but kept in and exposed to the heat a minute or two longer,
thus gaining the quality indicated by the honeycombed surface to any
extent desired, the said quality being desirable for some purposes and
not for others.
In applying the process to the manufacture of steel it is carried on in
either manner already described, but with smaller charges, until the jets
of gas escaping from the molten metal appear in the shape of small blue
flames, but the charge is not drawn at this point. At the end of two or
three minutes the flames disappear, and their subsidence is followed in
one or two minutes by brilliant scintillations caused by the boiling up
through the cinder of white hot molten metal, which appears in patches
resembling bright silver coins of various sizes. As soon as this ebullition
manifests itself the workman closes the damper and inserting the rabble
through the stopper hole proceeds to slowly stir the mass until it assumes
a slightly thickened or pasty condition, and commences to rise or swell
up in the furnace, which being observed the damper is opened, the fire

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Benjamin Joseph Barnard Mills in the Great Scal
Patent Office on the 4th May 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BENJAMIN
JOSEPH BARNARD MILLS, of the Firm of Harris and Mills, of 35,
Southampton Buildings, in the County of Middlesex, Patent Agent, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of November, in the year of
our Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Benjamin Joseph Barnard Mills, Her
special license that I, the said Benjamin Joseph Barnard Mills, my
executors, administrators, and assigns, or such others as I, the said
Benjamin Joseph Barnard Mills, my executors, administrators, and
assigns, should at any time agree with, and no others, from time
to time, and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF IRON AND STEEL," a communication to me from abroad by Charles
Burgess, of Portsmouth, in the County of Scioto, and State of Ohio,
United States of America, Iron and Steel Manufacturer, upon the
condition (amongst others) that I, the said Benjamin Joseph Barnard
Mills, my executors or administrators, by an instrument in writing,
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in
the Great Seal Patent Office within six calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Benjamin Joseph Barnard Mills, do
hereby declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement thereof, that is to say:-
This Invention relates in part to the fining or partial refining of cast
iron by the use of mineral coal in an ordinary puddling, or gas, or other

page_text: suitable closed or reverberatory furnace, or any furnace which may be
adapted for the carrying out of the process as herein-after set forth.
The Invention further relates to a rapid, economical, and effective
process for the manufacture of steel direct from cast iron in a common
puddling or other suitable furnace by a continuation of or addition to
the same process by which fined cast iron is produced, as herein-after
explained.
The Invention further relates to the production of a composite iron
for use in the production of chilled and other castings by the mixture of
fined cast iron with soft gray cast iron, as herein-after explained.
In carrying out the Invention a common reverberatory furnace with
sunken hearth may be employed. A. fire, which may be of ordinary coal,
having been raised in the fire-place of a puddling furnace or other
suitable closed or reverberatory furnace, a charge of broken pig or other
cast iron is placed on the hearth, and the ash-pit and damper being left
open so as to secure a through draft, the workman examines the charge
from time to time through the stopper hole, and as soon as the exposed
upper surface shows signs of partial fusion the workman gently turns
over the pieces so as to expose fresh surfaces to the action of the flame,
after which he keeps shifting the pieces until they are all melted down
into the condition of a "puddle." The workman then (the ash-pit and
damper remaining open) closes the stopper hole and stimulates the fire.
This process of intense heating and active combustion, without manipu-
lation of any sort, is permitted to continue for a period of five to fifteen
minutes or longer, according to tho quantity and quality of the metal,
until the workman closely watching the behaviour of the charge from
time to time through the stopper hole observes first at that portion of
the metal near the fire-bridge numerous jets of blue flame about the size
of the flame of an ordinary tallow candle. The tap hole is then opened
so as to allow the charge to flow out into a suitable shallow cast-iron
mould, such as customarily employed in the moulding of refinery metal,
and the crust of cinder separated by the application of cold water in the
usual way.
Iron thus refined may be used with great advantage, and a
large saving of expense in casting and in the manufacture of malleable
iron. It is well adapted for the manufacture of bells by reason of its
clearness. It may be remelted in a cupola for casting, or it may be re-
worked in the puddling furnace or knobbling fire or charcoal fire in any
customary manner for producing wrought iron.

page_text: It will be manifest that in carrying out the process the reverberatory
furnace may be arranged to take the molten metal direct from the
smelting furnace.
To hasten the refining process and at the same time effect a saving in
fuel tuyeres may be introduced through the side or sides or end or ends
of the refining hearth (whichever is most convenient), the said tuyeres
being so arranged as to carry a pressure of air or a blast into the body of
the molten metal. The hearth of the furnace being charged with raw
pig iron or cast iron, and the charge fused in the usual way by the heat
and flame passing over it from the fire-grate, the blast is turned on by
opening stop valves in the blast pipe. The atmospheric air being thus
forced into the body of molten iron the oxygen comes in contact with
the carbon, and quickly raises an intense heat in the metal and increases
the heat of the furnace. The blast may be checked from time to time
so as to enable the workman to observe when the metal is sufficiently
refined, which is known by the swelling and rising of the mass, and by
the appearance of small bluish flames produced by the combination of
jets of gas escaping from the molten mass, at which time the metal is
tapped out into suitable moulds.
By the introduction of a blast into the molten iron not only is the
refining operation quickened, but a larger quantity can be refined at one
charge, and a great saving in fuel is effected, the combustion of the
carbon by the contact of air furnishing the heat. By thus introducing
a blast into the furnace hearth, where the metal is taken directly from
the hearth of the smelting furnace or blast furnace, the fire-grate may
be dispensed with. entirely by the following means:-Fire is placed on
the refining hearth, the blast opened, and fuel added. The hearth soon
acquires an intense heat. The fuel may then be withdrawn from the
refining hearth with an iron rake or scraper, and the metal allowed to
flow from the smelting furnace on to the hearth of the hot refining
furnace. The charge of crude metal being in the refining furnace the
blast is applied and air forced into the body of molten metal, as before
explained. The combustion of carbon and other matter soon produces
an intense heat in the metal and in the furnace, and carries the refining
operation to any desired extent, the mass being tapped out when it is
observed to swell or rise and as soon as the blue jets appear.
The hearth of the refining furnace which is thus used in connection
with the melting furnace is similar to the hearth of a puddling furnace

page_text: If it be desired to produce a hard quality of steel the workman closes
the damper as soon as the mass has come to a full boil or a little before
a full boil is reached, according to the quality of steel desired and the
quality of metal employed, after which the damper remains closed until
the charge is withdrawn. If on the other hand a softer steel be desired
the damper may be closed at the same time as if making hard steel, but
not closed perfectly tight or close but left open a little until the mass
has arrived nearly to the spongy condition. The damper is then per-
fectly closed or the ebullition or boiling may be suffered to continue
with the damper open until the proper decarbonization is believed to
have been reached. The damper is then closed so as to stop the
decarbonization, and the metal becoming slightly cooled is seen to come
to the condition of a spongy mass which is then by means of a common
paddle or other suitable means quickly divided into two or more pieces
or left entire, and the piece or pieces are then balled and taken to the
hammer or squeezer and there obtain their proper shape for rolling or
otherwise working.
Whether the object be the refining of cast iron or the production of
steel, a flux may be advantageously applied to the iron when in a molten
state to assist in the expelling of impurities, such as sulphur, phos-
phorous, silicon, and others.
The flux may be composed of the following ingredients :-Sulphate
of iron, common soda, black oxide of manganese, coarse salt. These
may be mixed together with others in proportions according to the
quality of the pig iron employed, and will act as a stimulant in the iron,
and cause the impurities to escape more freely from the metal.
By the above described process a good and uniform quality of steel is
produced direct from the puddling furnace, suitable for forging and
welding, and containing sufficient carbon, so that it can be hardened and
tempered satisfactorily to adapt it for the manufacture of agricultural
implements, springs, or tools, or even cutlery, without the necessity of
recarbonizing.
The following are regarded as the characteristic features of the process
as applied to the manufacture of steel:-First exposing the molten
metal to intense heat until the appearance and disappearance of the
blue flames, then manipulating it slowly after the damper is raised the
first time, having the furnace as free from flame as possible, when the

page_text: mass reaches a full boil, then closing the damper to check the heat and
stop decarbonisation when a full boil is reached, or a little later if a
soft steel is desired.
The part of the Invention which relates to the production of compo-
site iron for chilled castings, or for other purposes, is in part based upon
the discovery that the fining or partial refining of cast iron, which did
not possess a chilling property, will impart such a property to it, and
that such refined cast iron can be advantageously mixed with a soft gray
iron to produce a composite iron possessing greater strength and hard-
ness, or adapted to receive a chill to any desired extent or degree 1
determined by the proportions in which the two qualities of iron are
combined.
In carrying out this part of the Invention, cast iron refined by the
process herein-before described, or by any other suitable process, is
combined with the softer gray cast iron in suitable proportions, according
to the depth of chill required or to the purposes for which the castings
may be designed.
For the manufacture of chilled castings, such as rolling mill rolls,
railway wheels, parts of agricultural implements, or for any purpose
where a good hard wearing iron is required, the following compounds 2
and others have been used with good effect:-

page_text: Having thus described the nature of the said Invention, and the mode
in which the same is carried into effect, I would have it understood that
what I claim is,―
First. The process described for the manufacture of fined or partially
refined cast iron, by subjecting the metal to a high heat apart from the
fuel in a covered furnace until the mass is seen to swell or jets of blue
flame appear.
Secondly. The manufacture of steel direct from cast iron in a puddling
or boiling furnace by having the furnace and boiling mass sufficiently
hot by the time the metal reaches a boil, so that the completion of the
boiling and balling and withdrawing is effected without additional fuel,
and having the furnace as free from flame as possible by the time the
metal reaches a full boil, and closing the damper when a full boil is
reached, or a little sooner or later, as may be desired, while the mass is
acquiring its final spongy condition.
Thirdly. A composite cast iron produced by the mixture of fined or
partially refined cast iron with soft gray cast iron, substantially as and
for the purposes set forth.
Fourthly. The process herein-before described of fining or partially
refining cast iron as a step in the manufacture of malleable iron
castings.
In witness whereof, I, the said Benjamin Joseph Barnard Mills,
have hereunto set my hand and seal, this Twenty-eighth day of
April, in the year of our Lord One thousand eight hundred and
seventy-four.