IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL AND IRON
Year: 1859

page_text: PROVISIONAL, SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the
24th January 1859.
I, ROBERT MUSHET, of Coleford, in the County of Gloucester, Metallurgist,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF CAST STEEL AND IRON," to be as follows:-
In. Letters Patent granted to me, and bearing date 22nd September 1856,
I have claimed the addition of a triple compound, consisting of or containing
iron, carbon, and manganese, to melted: cast iron which had been previously
decarbonized, of nearly decarbonized by forcing: or passing air. through it
whilst it was in a molten state, the addition: of. the said triple compound
improving the quality of: the iron or steel obtained froui such decarbonized or
nearly decarbonized cast iron.....
The essence of my present Invention :consists in adding to cast iron during
the time that it is being. decarbonized. by the action of air forced or passed
through, it whilst in a molten, state, successive quantities or proportions of a
triple compound, consisting of or, containing iron, carbon, and manganese, the
said compound, being either in a solid or in a melted state, the addition of the

page_text: said triple compound effecting an improvement in the quality of the products
obtained at the close of the operation, whether cast steel, as when the melted cast
iron is only so far decarbonized by the action of the air as to be in the state of
cast steel, or whether iron, as when the melted cast iron is so far decarbonized
by the action of the air as to be in the state of soft iron, and not in the state
of cast steel.
In carrying my Invention into effect, I proceed as follows:-I melt the
triple compound of iron, carbon, and manganese, in a melting pot or crucible,
or in a suitable melting furnace, and I then pour it from a pot or ladle in
small successive quantities from time to time, or in a small continuous stream
into the purifying vessel or furnace where the melted cast iron is being
<lecarbonized by the action of air forced or passed through it, so that the triple
compound of iron, carbon, and manganese may become mixed with the melted
cast iron whilst the latter is undergoing the process of decarbonization, but I
carefully avoid the sudden introduction of a large quantity of the melted triple
compound into the purifying furnace or vessel and amongst the melted cast
iron, as the sudden addition of a large quantity of the said triple compound
might occasion a violent and dangerous explosion. The addition of the triple
compound of iron, carbon, and manganese, may also be effected by stamping,
crushing, or granulating the said triple compound, and introducing it thus
pulverized or granulated in small successive quantities into the purifying
vessel or furnace, so that it may fall into and become mixed with the melted
cast iron, whilst the latter is undergoing the process of decarbonization by the
action of air forced or passed through it, or the triple compound may be
heated, but not so as to become molten, and may then be introduced into the
purifying vessel or furnace, so as to fall into the melted iron, wherein it will
be speedily dissolved, and with which it will become combined.
The proportions of the triple compound of iron, carbon, and. manganese to
be added to the melted cast iron which is being decarbonized by the action of
air forced or passed through it, may be varied at the will of the operator, but
I find, in practice, that from five pounds to twenty pounds by weight of the
triple compound of iron, carbon, and manganese is a sufficient quantity to add
to every one hundred pounds by weight of. the melted cast iron whilst the
latter is being decarbonized by the action of air forced or passed through it.
The compound of iron, carbon, and manganese which I employ in carrying
my Invention into effect, may be made by smelting or reducing iron ores con-
taining manganese, but I prefer to use the variety of white crystalline cast
iron made in Rhenish Prussia, and called "spiegel eisen." The said "spiegel
eisen" contains from two to eight parts by weight of manganese to every one
-----

page_text: hundred parts by weight of iron, together with the proportion of carbon con-
tained in cast iron. But I do not confine myself to any particular process or
method of preparing the triple compound of iron, carbon, and manganese.
The essence of my Invention consists in combining a triple compound of
iron, carbon, and manganese with melted cast iron whilst the latter is being
decarbonized by the action of air forced or passed through it in any convenient
vessel or furnace, and I prefer to add the triple compound of iron, carbon, and
manganese in a fluid or molten state to the melted cast iron, being careful,
however, to introduce the triple compound gradually and in small quantities,
so as to avoid the danger of an explosion, which might occur should a large
quantity of the triple compound be suddenly introduced into the melted cast
iron when the latter has been decarbonized to a considerable extent.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Mushet in the Great Seal Patent Office on the
22nd July 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
MUSHET, of Coleford, in the County of Gloucester, Metallurgist, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of January, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-second year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
mie, the said Robert Mushet, Her special licence that I, the said Robert
Mushet, my executors, administrators, and assigns, or such others as I, the
said Robert Mushet, 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 CAST STEEL AND IRON," upon the condition (amongst
others) that I, the said Robert Mushet, 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
to be filed in the Great Seal Patent Office within six calendar months next
and inmediately after the date of the said Letters Patent.

page_text: NOW KNOW YE, that I, the said Robert Mushet, 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:-
In Letters Patent granted to me, and bearing date the Twenty-second.day
of September, One thousand eight hundred and fifty-six, I have described and
claimed the addition of a triple compound, containing iron, carbon, and
manganese to melted cast iron, which said cast iron bad been previously.
decarbonized or nearly decarbonized by forcing or passing air through it.whilst
it was in a molten state; the addition of the said triple compound improving the
quality of the iron or steel obtained from such decarbonized or nearly decar-
bonized cast iron.
The essence of my present Invention consists in adding to cast iron during
the time that it is being decarbonized by the action of air forced or passed
through it whilst in a molten state, successive quantities or portions of a triple
compound, consisting of or containing iron, carbon, and manganese, the said
compound being either in a solid or in a melted state, the addition of the said
triple compound effecting an improvement in the quality of the products
obtained, whether the product. be steel obtained by decarbonizing the said cast
iron to the extent necessary to reduce its carbon to the relative proportions
existing in cast steel or iron obtained by continuing the decarbonizing process
until the carbon has been wholly removed, or removed as far as practicable by
the said decarbonizing process.
In carrying my Invention into effect, I proceed as follows:-I melt the
triple compound of iron, carbon, and manganese in a melting pot or crucible,
or in a suitable melting furnace, and I then pour it from a pot or ladle in
small successive quantities from tinie to time, or in a small continuous 'stream
into the purifying vessel or furnace, where the melted cast iron is being
decarbonized by the action of air forced or passed through it, so that the triple
compound of iron, carbon, and manganese may become mixed with the melted
cast iron whilst the latter is undergoing the process of decarbonization; but I
carefully avoid the sudden introduction of a large quantity of the melted triple
compound into the purifying furnace or vessel, and amongst the melted cast
iron, as the sudden addition of a large quantity of the said triple compound,
whilst the air is passing through the molten iron, might occasion a violent and
dangerous explosion. The addition of the triple compound of iron, carbon,
and manganese may also be effected by stamping, crushing, or granulating the
said triple compound, and introducing it thus pulverized or granulated in
small successive quantities into the decarbonizing vessel or furnace, so that it

page_text: may fall into and become mixed with the melted cast iron, whilst the latter is
undergoing the process of decarbonization by the action of air forced or passed
through it, or the triple compound may be heated to a temperature insufficient
to melt it, and may be then introduced into the decarbonizing vessel or
furnace so as to fall into the melted iron, wherein it will be speedily dissolved,
and with which it will become combined. The proportions of the triple com-
pound of iron, carbon, and manganese to be added to the melted cast iron
which is being decarbonized by the action of air forced or passed through it
may be varied at the will of the operator; but I find, in practice, that from
five pounds to twenty pounds of the triple compound of iron, carbon, and
manganese is a sufficient quantity to add to every one hundred pounds of the
melted cast iron, whilst the latter is being decarbonized by the action of air
forced or passed through it.
The compound of iron, carbon, and manganese which I employ in carrying
my Invention into effect may be made by smelting or reducing in a blast
furnace iron ores containing manganese; but I prefer to use the variety of
white crystalline cast iron made in Rhenish Prussia, and called "spiegel
eisen." The said "spiegel eisen" contains from two to eight parts by weight
of manganese to every one hundred parts by weight of iron, together with the
proportion of carbon contained in cast iron; but I do not confine myself to
any particular process or method of preparing the triple compound of iron,
carbon, and manganese.
I introduce the melted compound of iron, carbon, and manganese through
an opening in the side or top of the decarbonizing vessel or chamber in
5 which the cast iron is being decarbonized by passing air through it. When
the cast iron operated upon is about one ton in weight, I begin to introduce
the said compound as soon as the decarbonizing process has commenced,
pouring in from a ladle from two to three pounds of the molten triple com-
pound every half minute or thereabouts until the decarbonizing process is
O completed, or I suffer the melted triple compound to flow into the decarbo-
nizing vessel or chamber in a small continuous stream.at the average rate of
from four to six pounds during every minute that the purifying process is
continued. When a larger or a smaller quantity of cast iron is being decar-
bonized, I introduce a proportionally larger or smaller quantity of the said
5 triple compound.
When the triple compound of iron, carbon, and manganese is to be added
in the cold state or in lumps (which have been previously heated to a tem-
perature insufficient to melt them) to the melted cast iron, being decarbonized
by passing air through it, I drop the requisite quantities of the cold granulated

page_text: or crushed "spiegel eisen," or of the heated lumps of the said "spiegel eisen"
into the melted cast iron at regular intervals, that is to say, at the average rate
of from four to six pounds of, either the crushed or granulated spiegel eisen,
or of the heated lumps of the said spiegel eisen during every minute that the
purifying process is continued.
I do not, however, confine myself to the relative proportions I have
described, as the proportion of the said spiegel eisen relatively to that of the
melted cast iron to which it is added may be varied, without departing from
the nature of my Invention. The decarbonized cast iron, whether decar-
bonized only so far as to be in the state of steel or decarbonized until it is in the
state of malleable iron, is, when thus treated by my process, to be poured into
ingot moulds or other moulds, such as may be required.
Having thus described the nature of my Invention and the manner in
which it may be carried into effect, I wish it to be understood that the
essence of my Invention consists in adding a triple compound of iron, carbon,
and manganese to melted cast iron whilst the latter is being decarbonized by
the action of air forced or passed through it; and I prefer to add the triple
compound of iron, carbon, and manganese in a fluid or molten state to the
melted cast iron, being careful, however, to introduce the triple compound
gradually and in small quantities at a time, so as to avoid the danger of an
explosion, which explosion might occur should a large quantity of the triple
compound be suddenly introduced into the melted cast iron after the latter
has been decarbonized, to a considerable extent, and whilst the air is being
passed through it.
In witness whereof, I, the said Robert Mushet, have hereunto set my
hand and seal, this Twelfth day of July, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witnesses,
EDWP M. MUSHET,"
Coleford, Gloucestershire.
BROOKLYN MUSHET,
Coleford, Gloucestershire.
ROBT MUSHET. (L.S.)