IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL AND ITS DERIVATIVES
Year: 1867

page_text: LETTERS PATENT to Clinton Edgcumbe Brooman, of the Firm of Robertson,
Brooman, and Company, of 166, Fleet Street, in the City of London,
Patent Agents, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE
OF CAST STEEL AND ITS DERIVATIVES."-A communication from abroad by
Emile Martin and Pierre Emile Martin, both of Paris, France.
Sealed the 14th January 1868, and dated the 25th July 1867.
PROV
Brooman at the Office of the Commissioners of Patents, with his Petition,
on the 25th July 1867.
I, CLINTON EDGCUMBE BROOMAN, of the Firm of Robertson, Brooman, and
Company, of 166, Fleet Street, in the City of London, Patent Agents, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF CAST STEEL AND ITS DERIVATIVES," to be as follows:-
The object of this Invention is certain practical processes for manufacturing
on the sole of a reverberatory furnace cast steel and its derivatives of superior
quality and with greater economy than with the ordinary processes. These

page_text: processes of manufacture by giving means of dosing the materials, and c
varying the qualities during an operation having an average duration o
6 hours, permit of obtaining the following products:-Hard cast steel o
commerce fit for the manufacture of tools and other purposes; soft cast stee
(homogeneous metal) susceptible of being welded and wrought when hot, an
of being drawn when cold; cast iron (fer fondu) having the resistance o
wrought irou without having been hammered or rolled; mixed metal, which
will replace cast iron (fonte de fer) for moulding, as it will present mor
resistance to the blow.
The process is based on this property, that by the fact of the high temperature
of the bath (3400 to 4250 degrees Fahrenheit), and by the presence of the
oxide of iron mixed with the casting I decarburet the casting without the
intervention of any current of air or steam; thus the oxide combined with
the high temperature plays the same part as the air which is ordinarily forced
in; in other words, if under the influence of a high temperature oxide is
added to the bath, the casting is decarburetted; if, on the contrary, some of
the casting is added to it the bath is carburetted. The economy of this process
of refining is based on the simplicity of the operation, reducing the cast iron
into cast steel of commerce, and into homogeneous metal, which will replace,
with the advantage of its fusibility in many employments, the wrought iron
which receives shapes in the ordinary processes only by hand labor or by the
blow of the hammer or stamp, while in this process the homogeneous metal
is only run off or tapped and rolled. The refining by this Invention is
effected in a few hours by fusions of from 6 to 10,000 lbs. By this Invention
I can run in cast steel, homogeneous metal, cast iron, or mixed metal, pieces
of the largest weight and dimensions of a single casting, by employing one or
several furnaces, an important fact which has hitherto not been realized.
The Invention consists in forming on the sole of a reverberatory furnace
(by preference a Siemens' furnace) a bath of cast iron (fonte) which has been
brought to a high temperature; this is effected by heating the casting in the
bath for about half an hour. This bath having been thus heated there is
thrown therein either ore, simply roasted, but by preference roasted and then
cemented, in small portions of from 20 to 40 lbs.; or there is thrown therein
pieces of puddled steel or of granulated or ribbed iron (fer à grain ou à nerf)
of old rails or of scraps, each piece of the weight of about 18 lbs., and which
have been previously heated to a bright red or yellowish white heat in an
adjoining furnace, or in a special compartment of the same reverberatory
furnace. The ore is also itself heated before being put in the bath. The
temperature of the furnace is kept constant during all the operation at from

page_text: 3400 to 4250 degrees Fahrenheit, and the flame is kept reductive by the
abundance of the combustible gases. The addition of the ore or of the pieces
of iron or steel is made by charges of from 200 to 400 lbs., according to the
importance of the original bath of the casting, at intervals of about 20 minutes.
The quality of the material or the degree of refining of the bath is judged by
a quantity of about 1 lb., which is taken out with a ladle and run into a
small mould. Arrived at a point of refining where the bath passes to the
state of cast iron (fer fondu) some cast iron (fonte) must be added, by
preference manganesiferous, called spiegel eisen. The proportions of this iron
added at the end vary according to the estimation of the attendant according
to the quality of the test, and according to the nature of the metal which is
to be obtained. In proportion as the time is prolonged without running or
tapping after the fusion of the added metal the bath becomes more and more
soft. The 3 divisions of the operation are thus quite defined and characteristic,
viz., original bath of cast iron (fonte) refining pushed further than is necessary
by the addition of iron or ore, and return of the bath to the desired point by
adding thereto a proportion of metal of suitable quality and weight. By
varying the doses the different products above cited are obtained, viz.,―
1st. Mixed Metal.-Dose: Original bath of 1600 lbs. of grey cast iron or
cast iron with facets (fonte grise ou à facettes), addition of 2400 lbs. of iron,
steel, or scraps (the proportion of the iron diminishes with the addition of
the ore, and the nature even of the metals), and addition of 1200 lbs. of
metal at the end. The product can be rolled and cut at cherry red. The
ingots and mouldings are free from blemishes. A prolonged reheating softens
the tapped or run pieces into mixed metal, and finishes by transforming them
completely into malleable cast iron. To render the bath very homogeneous
I reserve a charge or two of iron for the end of the operation, and stir for
some instants before running off. The duration of the operation is about
5 hours, and the loss about 4 per cent.
2nd. Steel for Tools.-Dose: Original bath 1600 lbs. of grey cast iron
(fonte grise) addition of 2600 lbs. of puddled steel of the same castings, final
addition of 400 to 500 lbs. of spiegel eisen. The duration of the operation is
about 6 hours, and the loss 6 or 7 per cent. According to the nature of the
irons I go down as far as 2 parts of cast iron (fonte) and one part of puddled
steel and iron with 200 parts of ore.
3rd. Homogeneous Metal or Soft Steel.-These products are tempered,
welded, and eliquated (ressuer) like iron, and are easily worked at all
temperatures. Dose: 1200 lbs. of spiegel eisen, 2000 of soft granular
iron (fer doux à grain) from the same castings, 200 to 300 of the same

page_text: fusion falls into one of several receivers mounted on a carriage made to run
on rails by means of a pinion and rack. The charges are inserted through
a door by a suitable appliance, which may slide on a roller.
It will be seen from the foregoing description that this Invention consists
in a process for the direct refining of the casting or cast iron (fonte) into cast
steel and its derivatives, the process being based on the principle of high
temperature and the carburation and decarburation of the bath without any
blowing or forcing in of air, and on the variable doses of the ore and of the
metals added.
By this Invention there is economical production and manufacture of
industrial products of a superior quality and of a new nature, especially as
regards the homogeneous metal, the mixed metal, and the cast iron (fer
fondu
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Clinton Edgcumbe Brooman in the Great Seal Patent
Office on the 25th January 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CLINTON
EDGCUMBE BROOMAN, of the Firm of Robertson, Brooman, and Company, of
166, Fleet Street, in the City of London, Patent Agents, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing. date the Twenty-fifth day of July, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Clinton Edgcumbe Brooman, Her special licence that I, the said
Clinton Edgcumbe Brooman, my executors, administrators, and assigns, or
such others as I, the said Clinton Edgcumbe Brooman, my executors, adminis-
trators, 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 CAST STEEL AND ITS
DERIVATIVES," (communicated to me from abroad by Emile Martin and Pierre
Emile Martin, both of Paris, France.) upon the condition (amongst others)
that I, the said Clinton Edgcumbe Brooman, 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 Inven-
tion, and in what manner the same was to be performed, and cause the same

page_text: to be filed in the Great Seal Patent Office within calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Clinton Edgcumbe Brooman, 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, reference being bad to the Drawings hereunto
annexed, that is to say:-
The object of this Invention is certain practical processes for manufacturing
on the sole of a reverberatory furnace cast steel and its derivatives of superior
quality and with greater economy than with the ordinary processes. These
processes of manufacture by giving means of dosing the materials and of
varying the qualities during an operation having an average duration of 6
hours permit of obtaining the following products-Hard cast steel of.com-
merce fit for the manufacture of tools and other purposes; soft cast steel
(homogeneous metal) susceptible of being welded and wrought when hot and
of being drawn when cold; cast iron (fer fondu) having the resistance of
wrought iron without having been hammered or rolled. Mixed metal which
will replace cast iron (fonte de fer) for moulding, as it will present more
resistance to the blow.
The process is based on this property, that by the fact of the high
temperature of the bath (2900 to 3650 degrees Fahrenheit) and by the
presence of the oxide of iron mixed with the casting I decarburet the casting
without the intervention of any current of air or steam. Thus the oxide com-
bined with the high temperature plays the same part as the air which is
ordinarily forced in; in other words, if under the influence of a high tempera-
ture oxide is added to the bath the casting is decarburetted; if, on the contrary,
some of the casting is added to it the bath is carburetted. The economy of
this process of refining is based on the simplicity of the operation reducing
the cast iron into cast steel of commerce and into homogeneous metal which
will replace, with the advantage of its fusibility in many employments, the
wrought iron which receives shapes in the ordinary processes only by hand labor
or by the blow of the hammer or stamp, while in this process the homogeneous
metal is only run off or tapped and rolled. The refining by this Invention is
effected in a few hours by fusions of from 6 to 10,000 lbs. By this Invention
I can run in cast steel, homogeneous metal, cast iron, or mixed metal, pieces
of the largest weight and dimensions of a single casting by employing one or
several furnaces; an important fact which has hitherto not been realized.
The Invention consists in forming on the sole of a reverberatory furnace
(by preference a Siemens' furnace) a bath of cast iron (fonte) which has been

page_text: brought to a high temperature; this is effected by heating the casting in the
bath for about half an hour. This bath having been thus heated there is
thrown therein either ore simply roasted, but by preference roasted and then
cemented in small portions of from 20 to 40 lbs. ; or there is thrown therein
pieces of puddled steel or of granulated or ribbed iron (fer à grains ou à nerf)
of old rails or of scraps, each piece of the weight of about 18 lbs., and which
have been previously heated to a bright red or yellowish white heat in an
adjoining furnace, or in a special compartment of the same reverberatory
furnace; the ore is also itself heated before being put in the bath. The tem-
perature of the furnace is kept constant during all the operation at from
2900 to 3650 degrees Fahrenheit, and the flame is kept reductive by the
abundance of the combustible gases. The addition of the ore or of the pieces
of iron or steel is made by charges of from 200 to 400 lbs. according to the
importance of the original bath of the casting at intervals of about 20 minutes.
The quality of the material or the degree of refining of the bath is judged by
a quantity of about 1 lb., which is taken out with a ladle and run into a small
mould. Arrived at a point of refining where the bath passes to the state of
cast iron (fer fondu) some cast iron (fonte) must be added, by preference
manganesiferous, called spiegel eisen. The proportions of this iron added at
the end vary according to the estimation of the attendant, according to the
quality of the test, and according to the nature of the metal which is to be
obtained. In proportion as the time is prolonged without running or tapping
after the fusion of the added metal the bath becomes more and more soft.
The three divisions of the operation are thus quite defined and characteristic,
viz., original bath of cast iron (fonte), refining pushed further than is
necessary by the addition of iron or ore, and return of the bath to the desired
point by adding thereto a proportion of metal of suitable quality and weight.
By varying the doses the different products above cited are obtained, viz. :-
1st. Mixed Metal.-Dose: Original bath of 1600 lbs. of grey cast iron or
cast iron with facets (fonte grise ou à facettes), addition of 2400 lbs. of iron,
steel, or scraps (the proportion of the iron diminishes with the addition of the
ore and the nature even of the metals), an addition of 1200 lbs. of metal at
the end; the product can be rolled and cut at cherry red; the ingots and
mouldings are free from blemishes. A prolonged reheating softens the tapped
or run pieces into mixed metal, and finishes by transforming them completely
into malleable cast iron. To render the bath very homogeneous I reserve a
charge or two of iron for the end of the operation and stir for some instants
before running off. The duration of the operation is about 5 hours, and the
loss about 4 per cent.

page_text: .
2nd. Steel for Tools.-Dose: Original bath 1600 lbs. of grey cast iron
(fonte grise) addition of 2600 lbs. of puddled steel of the same castings, final
addition of 400 to 500 lbs. of spiegel eisen. The duration of the operation is
about 6 hours, and the loss 6 or 7 per cent. According to the nature of the
irons I go down as far as 2 parts of cast iron (fonte) and one part of puddled
steel and iron with 200 parts of ore.
Third. Homogeneous Metal or Soft Steel.-These products are tempered,
welded, and eliquated (ressuer) like iron, and are easily worked at all tem-
peratures. Dose: 1200 lbs. of spiegel eisen, 2000 of soft granular iron (fer
doux à grain) from the same castings, 200 to 300 lbs. of the same castings
at the end of the operation. The duration of the operation is 7 hours, and
the loss 9 per cent.
Fourth. Cast Iron (fer fondu).-This cast iron is a metal which employed
in the state of run pieces has without being wrought the resistance when cold
of wrought iron; it presents the same aspect of fracture, and is rolled and
worked at red and white heats welding like iron. The fusion of the iron
scrap or puddled steel in the bath or the refining by the ore (alone or mixed
with scrap) is pushed to the maximum; as for the preceding operations about
5 per cent. is added of grey silicious and manganesiferous castings, or castings
with large facets (fontes à grandes facettes). The proportion of 5 per cent.
is sensibly augmented up to 20 per cent. with grey wood castings (fontes
grises au bois), certain qualities of which become refined very rapidly, and
without stirring by the sole effect of the high temperature already obtained
from the bath of cast iron. The duration of the operation is from 6 to 7 hours,
and the loss about 12
per cent.
The following is an example of cast steel with a strong proportion of casting
or cast iron:-
2000 lbs. of cast iron (fonte).
800 "
serap (riblon).
400
ore.
"
800
of cast iron at the end.
"
Example with cast iron (fonte) and ore alone:-
2000 lbs. of cast iron.
600 roasted oxydulated manganesiferous ore.
وو
200 lbs. for cast iron (fer fondu).

page_text: rehning; it is the same with the casting previously w
with the ore.
The gas furnace, which it is preferred to use for carrying out this Invention,
is represented in longitudinal section in Figure 1, and in transverse section in
Figure 2. At A is the door, which is opened for charging the furnace by
means of a suitable tool which is made to slide on a roller B. C is the sole,
which is of cast iron and has spread on it a bed of sand serving as a bottom
to the metallic bath. Below the sole C is an empty space E to receive air,
At G, G', are the regenerating compart-
vapour, or spray to cool the sole.
ments of the gas furnace. The tap hole or outflow C¹ is prolonged beyond
the masonry as well as the bed of sand D¹. The running off or tapping of
the metallic bath is effected by a spout H. When it is desired to run off the
aperture I is opened by a proper tool. The metal in a state of fusion falls
from the spout H into one of several receivers K mounted on a carriage made
to run on rails M, M, by means of a pinion O and rack P.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I claim as the "Improve-
ments in the Manufacture of Cast Steel and its Derivatives,"
First, the manufacture at one continuous operation on the sole of a
reverberatory furnace heated by gas, of four kinds of cast metal, viz., hard steel,
soft steel, cast iron (fer fondu), and mixed metal by the simple variation of the
doses; this continuous process comprising three features, first, the original
bath of casting; 2nd, the refining in excess by the addition of iron or ore;
and, third, the return of the bath to the desired point by adding a fresh
quantity of casting, and the process being based on the high temperature of the
metallic bath, and on the carburation and decarburation of the metallic bath,
all as herein-before described.
Second, the refining of the casting directly by the chemical action of oxide
of iron, as herein-before described, without any injection of air or steam.
Third, the fusion of the casting in a liquid bath, the surface of which is
preserved from oxidation by a gaseous layer always reductive, as herein-before
described.
Fourth, the manufacture of cast steel and its derivatives on the sole of a
furnace, below which is an empty space for cooling it, as herein-before
described.
Fifth, the decarburation of the casting in presence of solid matters which
will absorb the carbon, such as ores and metals, of iron and steel under the
simple action of a very high heat (2900 to 3650 degrees Fahrenheit), as
berein-before described.

page_text: Sixth, regulating the decarburation and the recarburation of the bath by
varying the work of the furnace, and the dosing of the materials according
to the quality of steel or metal to be produced, as herein-before described.
In witness whereof, I, the said Clinton Edgcumbe Brooman, have here-
unto set my hand and seal, this Twenty-fourth day of January, One
thousand eight hundred and sixty-eight.
C. E. BROOMAN. (L.S.)