IMPROVEMENTS IN THE PROCESSES AND APPARATUSES FOR CONVERTING CAST IRON INTO STEEL
Year: 1868

page_text: LETTERS PATENT to Aristide Balthazard Bérard, of Avenue Montaigne,
Paris; in the Empire of France, Civil Engineer, for the Invention of
, "IMPROVEMENTS IN THE PROCESSES AND APPARATUSES FOR CONVERTING
CAST IRON INTO STEEL."
Scaled the 1st April 1869, and dated the 23rd October 1868.
COMPLETE SPECIFICATION filed by the said Aristide Balthazard
Bérard at the Office of the Commissioners of Patents, with his
Petition and Declaration, on the 23rd October 1868, pursuant to
the 9th Section of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ARISTIDE
BALTHAZARD BÉRARD, of Avenue Montaigne, Paris, in the Empire of
France, Civil Engineer, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
THE PROCESSES AND APPARATUSES FOR CONVERTING CAST IRON INTO STEEL," and
have petitioned Her Majesty to grant unto me, my executors, adminis-
trators, and assigns, Her Royal Letters Patent for the same, and have.
made solemn Declaration that I verily believe myself to be the first and
true Inventor thereof.
NOW KNOW YE, that I said Aristide Balthazard Bérard, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention, and the

page_text: manner in which the same is to be performed, reference being had to
the Drawing hereto annexed, and forming part of this Specification, and
to the figures and letters marked thereon.
on the
My Invention relates to Letters Patent granted to me
Twentieth day of June, One thousand eight hundred and sixty-six, and-
consists in improvements in the arrangements and means therein
described for converting cast iron into steel direct by means of gases.
To make my Invention better understood I will proceed to describe
my improvements by reference to the accompanying Drawing, in which
Figure 1 represents a longitudinal section of the furnace; Figure 2 is a
transverse section of the same, and Figure 3, a plan. In the various
Figures the same letters represent parts which are similar.
To obviate the difficulties that may arise in practice from the employ-
ment of a furnace with a double sole plate, in which two operations are
combined, and must be conducted, so to speak, simultaneously, I make
use of a furnace with a single moveable sole plate A. This sole plate
is worked by means of an hydraulic press A', and may thus be lowered,
rapidly raised, or removed at will to be replaced by another.
The gases which I employ by preference are produced by an appa-
ratus of a peculiar construction, described in the Specification of the
said Letters Patent. The gases are conducted into the furnace by
annular plunging tuyeres in order to highly heat the sole plate of the
furnace and protect the arch. The heated air coming in at the centre
part of the tuyere is regulated by means of registers so as to obtain an
In order to utilize as much as
oxidizing or reducing flame at will.
possible the heat given off by the combustion of the gases a sole plate B,
with an inclined fusing surface B', is placed in continuation of the
moveable sole plate for the fusion of the cast iron, of mixture, or of
addition. Thus there is always cast iron at command, which is intro-
duced into the bath at the required time by means of a moveable pipe.
In continuation of the surface B' is placed another inclined surface C on
which the jets of molten metal or the different fragments of steel to bo
introduced in the hot state into the bath are heated to white heat by an
open fire or in earthen muffles. The remaining parts of the heat of the
lost gases are utilized for heating the air and gases serving for the
injection herein-after described. These apparatuses are placed in con
tinuation of the furnace, properly so called, in the space G, II, and are
composed of partitioned bells P, P, P, P, placed upon cases, and having

page_text: a free expansion. In front of the apparatus for heating the air and
gases one or several chambers D may be placed for the purpose of
annealing the ingots or moulded pieces especially for the trial ingots.
The cast iron is brought in a liquid state on to the moveable sole plate A
formed of carbonaceous cement,. after taking it either from a blast
furnace or from furnaces for the second melting, whether reverberatory
or cupola. The charge varies according to the dimensions of the furnace,
the average is from three to six tons. The converting furnace is first
raised to a high temperature; as soon as the cast iron is conducted into
it the purifying process may be at once commenced; then the decarbu
ration, which is carried to the required extent to convert it into steel
of more or less softness: I introduce into the bath of cast iron the two
cylindrical plunging tuyeres E, E', which are perforated longitudinally
with several holes. These tuyeres are placed on each side of the furnace
so as to communicate to the liquid mass a rotatory motion on itself, and
at the same time a violent ebullition. I can at option inject air alone
at the required pressure, or a mixture of air and purified gas, or gas,
only into the liquid metal. By this means by raising the temperature
to a high degree (which is necessary for the success of the operation)
an intense oxidizing reaction or one so moderate as to render it neutral
is produced. By increasing the proportion of the injection gas relatively
to that of the air, I obtain a reducing action increasingly more intense.
ntil the extreme limit of the gas only is reached, then a gradual fall
of the temperature takes place. By this means the time which the
reduction will take may be determined when using gas without mixture
of air. The means afforded for varying the quantity of the air and gas
in the desired proportions, according to the nature of the cast iron,
allows of recarburetting it by means of the carbon in carburetted
hydrogen of the gases injected into the bath, and of prolonging the
operation as much as desired without forming much refuse, as the
hydrogen acting not only as a reducing agent, but also as a purifier of
the sulphur and phosphorous, restores the oxide of iron to its radical
or base.
T
LL

page_text: steel. At this stage the trial pieces should be frequently taken. The
injection into the bath should then consist of air only, or of air con-
taining little gas. Towards the end of the operation the scoriæ are run
off. The draught of the chimney is regulated by means of a butterfly.
valve L placed at its lower part. In the course of the operation a
compound of charcoal powder, with the addition of sea salt, may be
injected with the air mixed with gas. This mixture is contained in
receivers F, F, suitably arranged, and is regularly furnished to the
current of air, which carrics it along in its course. I can also introduco
peroxide of manganese and limo with the compound, and obtain a more
liquid scorice less charged with oxide of iron; thus the temperature
of the bath becomes higher, and the intensity of the purifying action is
increased. The purified gas of injection, the production of which is
almost always the same, and sometimes in excess of the quantity
necessary for the injection into the bath, is then directed by the
tuyeres M, M, on to the bath of cast iron of addition, care being taken
to avoid as much as possible its decarburation.
By means of the arrangements herein-before described I am enabled
to act with great precision on the bath of cast iron alternately by
oxidation or reduction at option. The cast iron may be recarburetted
and the operation continued as long as desired. The principle is the
same as that described in my before said Letters Patent, but the means
of execution are different.
One of the results of these arrangements is to localise in the metallic
bath the high temperature produced, which assists greatly the economy
and success of the operation, and the furnace is less injured, and its
length of wear is increased. The use of hydrogen in this process serves
to considerably lessen the waste of metal, and improves the quality of
the steel. When the steel has attained the required degree of decarbu-
ration the casting is commenced. The steel is placed in a pocket
provided with a valve, and is distributed in ingot moulds, or moulds
which are previously heated to a high temperature by means of gas
produced by the herein-before stated patented apparatus, which allows
of its distribution to any required distance, and renders the operation
easy.
Having thus described my Invention, and the manner of carrying the
same into effect, what I claim as my Invention and desire to be protected

page_text: Firstly. The employment of a single reverberatory furnace with a
single moveable sole plate heated by gas, with annular inclined tuyeres,
as hercin-before described and represented in the Drawing.
Secondly. The employment of the hydraulic press to move the
moveable sole plate.
Thirdly. The arrangement of the sole plate B, of the inclined
surface B', of the sole plate C, and of the annealing furnaces D, D, in
continuation of the working sole plate for effecting the fusion of the cast
iron of addition, and the re-heating of the jets and fragments of steel;
as also for the annealing of the ingots and other articles by means of
the lost heat, and in presence of one or several jets of reducing gas,
as hercin-before described and shewn in the accompanying Drawing.
Fourthly. The employment of two plunging tuyeres, acting simul-
taneously in an opposite direction, and so placed as to produce a rotatory
movement of the metallic bath, as herein-before described and shewn in
the accompanying Drawing.
Fifthly. The use of a mixture, with a proportion of air and gas,
variable at will, for injection into the interior of the bath of cast iron, or
for the injection therein of the air and gas by separate pipes whatever
be the form of the furnace, as herein-before described. .
Sixthly. The obtaining the return of the purified gas from the over-
flow of the injection on to the sole plate of fusion of the cast iron of
mixture or addition.
Seventhly. The injection into the metallic bath of pulverized charcoal
with a flux having a salt base, with or without manganese and lime, in
conjunction with the other arrangements of the apparatus.
Eighthly. The employment of gases for heating the interior of the
ingot moulds, and moulds for casting steel and other metals..
In witness whereof, I, the said Aristide Balthazard Bérard, have
hereto set my hand and seal, this Fourteenth day of October,
in the year of our Lord One thousand eight hundred and sixty-
eight.