IMPROVE- MENTS IN THE MANUFACTURE OF CAST STEEL
Year: 1864

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street,
in the City of London, Patent Agent, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF CAST STEEL."-A communication from
abroad by François Marie Emilie Martin and Pierre Martin, of
Paris, France.
Sealed the 10th February 1865, and dated the 15th August 1864.
PROVISIONAL SPECIFICATION left by the said Richard Archibald Brooman
at the Office of the Commissioners of Patents, with his Petition, on the
15th August 1864.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL," to be as follows:-
The object of this Invention is the direct manufacture of cast steel.
The process is applicable, 1st, to Siemens' gas furnace, and to all other
forms of reverberatory furnaces; 2nd, to cupola furnaces known as Wilkinson's,
and other analogous furnaces.
In the reverberatory furnace I fuse a quantity of cast iron; when this
bath reaches a sufficient temperature, from about 2,000° to 2,200° Fahrenheit,
(1,100° to 1,200° centigrade,) I add successively pieces of iron, natural steel,

page_text: iron or steel turnings, scrap, cold or raised to a red or white heat, or by
preference puddled balls cut into pieces, and inserted immediately or after
sweating into the cast-iron bath. When a certain quantity of this iron or
steel has become melted in the bath I run off about one-half of the bath, then
1 continue adding parts of iron or steel as before into the bath in the furnace.
The new bath being carried to a temperature of from about 2,700° to 3,300°
Fabrenheit (1,500° to 1,800° centigrade), and in the proportions necessary,
the steel will be formed and may be run off. Only a portion of this bath is
run off, in order to add a fresh quantity of iron or steel, and a fresh proportion
of cast iron, if need be. This second bath acquired, the manufacture of steel
may be continued for a week, more or less, and there will be a bath of cast
steel, which may be drawn off in proportion to the feed with iron and steel,
as before stated. I use a first intermediate bath to attain the second bath, in
order more rapidly to obtain the special steeling nature of this second bath.
However, the running off may be dispensed with, to set asido a part of this
first bath, because by increasing the proportion of iron in this bath it can be
brought to this special steeling nature, but necessitating longer time. As to
the respective proportions of cast iron or natural steel in all shapes to. con-
stitute the baths, they necessarily vary with the nature of the steel to be
obtained; but as an example, I give a mixture of 1 part of cast iron and 4 or
5 parts of iron or steel, without limiting myself to those proportions..
This process for the direct manufacture of cast steel would be insufficient
and incomplete without certain conditions of temperature, and of the nature
of the scum or dross covering the metallic bath, and to comply with the
conditions I remove from the bath the black scum charged with oxide of iron,
and substitute for it a clear scum free from oxide of iron, such as dross from
blast furnaces heated with wood, siliceous sand, and if necessary mixed with
lime or alumina, or other vitrifiable flux freed from oxide, and thereby
intended to successively dissolvo the greatest possible quantity of oxide thus
withdrawn from the bath. By this means the temperature is raised to the
highest degree, and the bath is cleansed of those matters injurious to the
quality of the steel. By the use of this flux the raising of the temperature
to the degree necessary for the formation of the steel is facilitated, and by
dissolving the oxide reduced in this clear scum the matter is purified, and its
quality assured.
The new process for the manufacture of cast steel in a reverberatory
furnace consists, 1st, in melting iron or natural steel in a bath of cast iron
lented in a reverberatory furnace, by preference in a Siemens" gas furnace,

page_text: and in continuing the operation by the successive running off of a part of the
bath brought to the proportions of temperature, and of mixture-of metallic
substances for the formation of cast steel, whereby a continuous working is
established, which is an essential characteristic of this Invention; 2nd, in
purifying these baths from the heavy and black scum charged with oxide of
iron, and substituting for it scum free, as far as possible, from oxide of iron
and other oxides, such as the vitreous scum from blast furnaces worked by
wood, siliceous sand,. and other vitrifiable and preserving flux.
Application of the Invention to cupola and other furnaces analogous in
form and use. It will be gathered that from the nature of the scum necessary
to render the steel malleable and capable of being. forged, that in melting
puddled balls in cupolas, alone or mixed with cast iron, and in a continuous
manner as they issue from puddling furnaces the black scum must be avoided.
To avoid this black scum. I melt abundantly with these balls and the cast-iron
scum of vitrifiable flux free from oxide of iron, to run it from the orifice of
the cupola until the scum becomes clear and free from oxide; by this. means
combinations of cast iron, natural steel,. and wrought iron above mentioned
may be produced, yielding products malleable at various degrees. Manganese,.
chlorides, or fluorides, nitrates, and various metals may be added to the bath
of cast iron.. I sometimes introduce- an oxygenated scoria, oxide of iron, of.
manganese, of lead, or a silicate,. or an oxygenated salt to act upon the cast
iron in fusion in the puddling or other furnace; then when the action is
deemed sufficient, the scorin is run out of the furnace and replaced by, a.
neutral or basic scum, such as salts of soda, potash, lime, and the like.. By
raising the temperature the matter is brought from a pasty state to a melted
state.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Archibald Brooman in the Great Seal "Patent.
Office on the 15th February 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD.
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of August, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year

page_text: of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Richard Archibald Brooman, Her special licence that
1, the said Richard Archibald Brooman, my executors, administrators,
and assigns, or such others as I, the said Richard Archibald Brooman,
my executors, administrators, and assigns, should at any timo agreo 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 MANU-
FACTURE OF CAST STEEL," (communicated to mo from abroad by Francois
Mario Emile Martin and Pierro Martin, of Paris, France,) upon tho
condition (amongst others) that I, the said Richard Archibald Brooman,
iny executors or administrators, by an instrument in writing under my, or
their, or one of their hands and seals, should particularly describe and ascer-
tain 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
Offico within six calendar months next and immediately after the date of
the said Letters Patent.
NOW KNOW YE, that I, the said Richard Archibald Brooman, do hereby
declare the nature of the said Invention, and in what manner the samo
is to be performed, to be particularly described and ascertained in and by
the following statement, that is to say :-
The object of this Invention is the direct manufacture of cast steel.
The process is applicable, 1st, to Siemens' gas furnace, and to all other
forms of reverberatory furnaces; 2nd, to cupola furnaces known as Wilkinson's,
and other analogous furnaces.
In the reverberatory furnace I fuse a quantity of cast iron; when this bath
reaches a sufficient temperature, from about 2,000° to 2,200° Fahrenheit
(1,100° to 1,200° centigrade), I add successively pieces of iron, natural steel,
iron or steel turnings, scrap, cold or raised to a red or white hent, or by
proference puddled balls cut into pieces, and inserted immediately or after
sweating into the cast-iron bath. When a certain quantity of this iron or
steel has become melted in the bath I run off about one-half of the bath,
then I continue adding parts of iron or steel, as before, into the bath in the
furnace. The now bath being carried to a temperature of from about 2,700°
to 3,300° Fahrenheit (1,500° to 1,800° centigrade), and in the proportions
necessary the steel will be formed and may be run off. Only a portion of this
bath is run off in order to add a fresh quantity of iron or steel, and a frosh

page_text: proportion of cast iron, if need be. This second bath acquired, the manu-
facture of steel may be continued for a week, more or less, and there will be
a bath of cast steel, which may be drawn off in proportion to the feed with
iron and steel, as before stated. I use a first intermediate bath to attain the
second bath, in order more rapidly to obtain the special steeling nature of this
second bath. However the running off may be dispensed with to set aside
a part of this first bath, because by increasing the proportion of iron in this
bath it can be brought to this special steeling nature, but necessitating longer
time. As to the respective proportions of cast iron or natural steel in all
shapes to constitute the baths, they necessarily vary with the nature of the
steel to be obtained; but as an example I give a mixture of one part of cast
iron and four or five parts of iron or steel without limiting myself to those
proportions.
This process for the direct manufacture of cast steel would be insufficient
and incomplete without certain conditions of temperature, and of the nature
of the scum or dross covering the metallic bath, and to comply with the con-
ditions I remove from the bath the black scum charged with oxide of iron,
and substitute for it a clear scum free from oxide of iron, such as dross from
blast furnaces heated with wood, silicious sand, and if necessary mixed with
lime or alumina, or other vitrifiable flux freed from oxide, and thereby
intended to successively dissolve the greatest possible quantity of oxide thus
withdrawn from the bath. By this means the temperature is raised to tho
highest degree, and the bath is cleansed of those matters injurious to the
quality of the steel. By the use of this flux the raising of the temperature
to the degree necessary for the formation of the steel is facilitated, and by
dissolving the oxide reduced in this clear scum the matter is purified, and its
quality assured.
I sometimes introduce an oxygenated scoria, oxide of iron, of manganese,
of lead, or a silicate, or an oxygenated salt to act upon cast iron in fusion in
a reverberatory, puddling, or other furnace, then when the action is deemed
sufficient, or when the iron has passed into the pasty state, the scoria is run
out of the furnace, and replaced by a scum, such as dross from blast furnaces,
vetrifiable earths, salts of soda, potash, lime, and the like. By raising the
temperature the matter is brought from a pasty state to a melted state.
Vetrifiable earths have the effect of stopping the oxydating action, and
assuring the metal passing into the state of cast steel.
Application of the Invention to cupola and other furnaces analogous in
form and use. It will be gathered that from the nature of the scum

page_text: necessary to render the steel malleable, and capable of being forged, that in
melting puddled balls in cupolas alone or mixed with cast iron, and in a con-
tinuous manner as they issue from puddling furnaces, the black scum must bo
avoided. To avoid this black scum I melt abundantly with these balls and
the cast iron scum or vertrifiable flux free from oxide of iron, to run it from
the orifice of the cupola until the scum becomes clear and free from oxide;
by this means combinations of cast iron, natural steel, and iron above
mentioned may be produced, yielding products malleable at various degrees.
Manganese, chlorides, or fluorides, nitrates, and various metals may be
added to the bath of cast iron. Plumbago, pounded coke, coal, charcoal, or
other reducing and carburating matters may also be added to the surface of
tho bath, or mixed with the materials to be melted, in order to change the
scum charged with oxide into scum freed from oxide, or nearly so..
The two following compositions have been found to answer well in carrying
out this Invention.
First, cast steel.-Mix with one part of steely charcoal or coke cast iron
(fonte aciereuse au bois ou au coko) melted in the furnace, two parts of
steely iron or puddled steel heated to whiteness, employing a clear scum as
a flux.
Second, malleable cast steel.-Mix with one part of soft charcoal or coke
cast iron previously melted, two parts of soft granulated iron, and by pre
ference "striped" iron heated to whiteness, a black scum being employed as
a flux.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declaro that I claim as the "Improve-
ments in the Manufacture of Cast Steel,"
-
First, melting iron or natural steel in a bath of cast iron heated in a
reverberatory furnace, by preference in a Siemens' gas furnace, and continuing
the operation by the successive running off of a part of the bath brought to
the proportions of temperature, and of mixture of metallic substances for
the formation of cast steel, whereby a continuous working is established,
which continuous working is an essential characteristic of this Invention, all
as herein-bofore described.
Second, purifying the bath of cast iron from the heavy and black scum
charged with oxido of iron, and substituting for it scum free, as far as
possible, from oxide of iron and other oxide, such as the vitreous scum from
blast furnaces worked by wood, silicious sand, and other vetrifiable and
preserving fluxes, as herein-before described.

page_text: Third, obtaining cast steel or products malleable at different degrees by
melting in cupola and other furnaces combinations of cast iron, natural steel,
and wrought iron by means of vetrifiable scums or fluxes free from oxide of
iron, as herein-before described.
In witness whereof, I, the said Richard Archibald Brooman, have here-
unto set my hand and seal, this Fifteenth day of February, One
thousand eight hundred and sixty-five.