Improvements in the Manufacture of Steel and Ingot Iron.
Year: 1890

page_text: Date of Application, 3rd Nov., 1890-Accepted. 6th Dec., 1890
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Steel and Ingot Iron.
A communication from abroad by JEAN MEYER, Directeur de la Société anonyme des
Hauts Fourneaux et Forges de Dudelange, of Dudelange, in the Grand Duchy
of Luxembourg.
I, PHILIP MIDDLETON JUSTICE, of 55 and 56 Chancery Lane, in the County of
Middlesex, Fellow of the Institute of Patent Agents, 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 :--
This invention relates to a new method of recarburization for producing, without
the use of spiegeleisen, steel of any degree of hardness, or homogeneous metal,
obtained by refining in acid or basic lined Bessemer converters, or in acid or basic
lined Siemens-Martin furnaces.
After having effected the decarburisation and dephosphorisation of the pig iron by
the Bessemer, Thomas-Gilchrist or Siemens-Martin process, or respectively by any
method of refining, the slag is removed as much as possible from the molten metal
and the metal is then recarburized by adding to the bath in the casting ladle
(previously deoxydised by an addition of ferro-manganese) briquettes made from coal,
anthracite, coke, graphite or charcoal with or without the addition of lime.
The desired substance or substances having a carbon base, intended for recarburation
are pulverised and formed into briquettes, either by hand or by means of a special
press.
The substance which serves to agglomerate the pulverised coal if desired is hydrate
of lime, which should be, as far as possible, free from inert matter.
In order to prepare these briquettes a mixture is made composed of 95 parts of
pulverised charcoal and from 5 to 8 parts of quick lime, which is transformed into
hydrate of lime, and afterwards mixed with as much water as may be necessary to
obtain a milky-white wash.
The pasty mass of coal and lime is allowed to stand during 12 to 30 hours before
the manufacture of the briquettes is proceeded with. The briquettes when made are
first dried in the atmosphere, and afterwards in a drying chamber, for so long a
period as may be necessary to give them a sufficient degree of coherence and
consistency.
In accordance with observation and the results of several experiments made with
various substances having a carbon base, it has been found that briquettes made with
so called non-bituminous or anthracite coal are preferable, for the purpose of
recarburization to those made with any other description of coal, or even with
graphite.
METHOD OF RECARBURIZATION.
After the pig iron has been decarburized or dephosphorised respectively in acid or
basic converters or Siemens-Martin furnaces, or refined in special furnaces; after the
refined metal, freed from its slag, has attained the quality desired, and after deoxidation
of the bath, the process of recarburization is proceeded with.
To this end the molten metal is poured slowly into the casting ladle, into which
about one third of the total weight of the briquettes have previously been placed.
The remaining two thirds of briquettes are added to the metal while it is being poured
into the ladle.

page_text: For producing steels containing as much as 13 per cent. of carbon, 25 kilogrammes
of anthracite briquettes have been used for every metric ton of pig charged into the
converter.
In recarburising the metal in accordance with the process above described, a portion
of the carbon in the briquettes is utilised for recarburation while the other portion is
oxidised and gives out an amount of heat, a large portion of which is absorbed by the
molten metal.
The end of the reaction may be waited for, without fear of the steel cooling or
partially setting while being poured.
The heat given out is even so intense that the lime which has served as an
agglutinant to the briquettes combines with the silica of the ash on becoming melted,
forming a slag which rises to the surface of the metal, while drawing along with it
and mixing with the scoria of dephosphorization and refining which remained in
suspension.
It is advisable to break up the crust of scoria which forms on the surface of the
metal during recarburisation in the ladle, in order that the gases produced by the
combustion of a portion of the carbon in the briquettes may be freely disengaged.
Steel thus obtained is very still, does not rise and yields sound ingots of very
uniform composition as regards the contents of carbon.
In four or five test samples taken at different periods from the same cast, an identical
amcunt of carbon was observed.
It is therefore easy and economical by the present method, to produce steels of
every description with predetermined amounts of carbon and manganese, without
the addition of spiegeleisen and without any intermediate receiver
apparatus.
or other
Having now particularly described and ascertained the nature of the said
invention as communicated to me by my foreign correspondent and in what manner
the same is to be performed I declare that what I claim is :-
The improvements in the manufacture of steel and ingot iron which consists in
recarburizing the metal in the casting ladle by means of briquettes made of carbon
with or without an addition of lime substantially as described.
Dated this 3rd day of November 1890
PHILIP M. JUSTICE.