AN IMPROVEMENT OR IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL."
Year: 1862

page_text: LETTERS PATENT to Robert Mushet, of Coleford, in the County of
Gloucester, Metallurgist, for the Invention of "AN IMPROVEMENT OR
IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL."
PROVISIONAL SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the
19th November 1862.
I, ROBERT MUSHET, of Coleford, in the County of Gloucester, Metallurgist,
do hereby declare the nature of the said Invention for "AN IMPROVEMENT OR
IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL," to be as follows:-
The iron ores termed sparry carbonates of iron, or spathose iron ores,
usually contain a large proportion of oxide of manganese in mixture with
oxides of iron. Such ores when smelted in a blast furnace or cupola with
charcoal or other fuel yield a species of pig iron which is essentially an alloy
of iron and manganese, containing also carbon. Such pig iron is termed
spathose pig iron, or steel pig, or, when white and regularly crystallized,
"spiegel eisen," that is, "looking-glass iron," from the brilliant facets it
exhibits when fractured. Franklinite pig iron is also an alloy of iron and
manganese, containing also carbon, and is one of the varieties of cast iron
which I employ in carrying my Invention into effect.

page_text: In the manufacture of cast steel & portion of spathose pig iron or Frank-
linite iron is frequently added to the mixture of materials which it is intended
to melt into cast steel, for the purpose of improving the quality of the cast
steel produced. To prepare the spathose pig iron for this purpose, it is broken
up into lumps of a size convenient for introducing into the melting pot or
crucible along with the materials or mixture of materials about to be melted
into cast steel.
Now, I have discovered that when the grey, white, or mottled spathose pig
iron, or steel pig, or Franklinite iron is previously prepared by the process of
hot granulation herein-after described, and is used with oxide of manganese,
the said oxide of manganese being either mixed with or added to the
granulated spathose iron, the said spathose pig iron affords better results
when added to the materials, or mixture of materials, which it is intended to
melt into cast steel, than it yields when employed without hot granulation.
The spathose pig iron or steel pig which I prefer to use is the grey, mottled,
or white steel pig, but not the white crystalline variety, or true spiegel eisen,
which I do not find improved by hot granulation. I prefer to employ spathose
pig iron or steel pig which has been smelted wholly with charcoal fuel; but
excellent results may also be obtained by the hot granulation of spathose pig
iron or steel pig, smelted either with a mixture of coke and charcoal fuel, or
wholly with coke fuel when the fuel employed is of good quality and tolerably
free from sulphur.
The process of hot granulation, by which I prepare the spathose pig iron or
steel pig for my purpose, is conducted as follows:-I break the spathose pig
iron or steel pig into lumps or pieces of from ten to forty pounds weight
each, as convenience may suggest. I heat these lumps of steel pig to a heat
somewhat short of their melting point, and I then subject the heated lumps to
the action of hammers, rollers, crushers, or stampers, in order to reduce them,
whilst rendered friable by their heat, to a coarse metallic gravel or powder.
When thus stamped, crushed, or pulverised whilst in a heated state, I mix the
granulated spathose pig iron when cold with oxide of manganese, adding
about one ounce of oxide of manganese to each pound of granulated spathose
pig iron or steel pig. When thus prepared the spathose pig iron or steel pig
is ready for use. I wish it to be observed that I do not claim the granulation
of spathose pig iron by running the said pig iron when melted into water.
The hot granulated spathose pig iron may be added to the materials or
mixture of materials intended to be melted into cast steel, either mixed or
unmixed with oxide of manganese, for the latter may be added separately;

page_text: but I prefer to mix the said oxide of manganese with the granulated spathose
pig iron, as it affords better results.
I do not confine myself to the proportion of oxide of manganese to
granulated spathose pig iron or steel pig which I have herein-before set
down, for the relative proportion of the oxide of manganese to the granulated
spathose pig iron may be varied at pleasure; but I have found the proportions
I have given afford excellent results.
The essence of my Invention consists in improving the manufacture of cast
steel by adding to the materials or mixture of materials which when melted
produces cast steel, spathose pig iron or steel pig which has been granulated
by the process of hot granulation herein described, whether the said hot
granulated spathose pig iron or steel pig be used mixed with oxide of
manganese, or the said oxide of manganese be added separately.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Mushet in the Great Seal Patent Office on the
13th May 1863.
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 Nineteenth day of November, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, 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 "AN IMPROVEMENT OR
IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL," upon the condition
(amongst others) that I, the said Robert Mushet, my executors or adminis-
trators, 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 Invention, 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

page_text: calendar months next and immediately after the date of the said Letters
Patent.
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:
The iron ores termed sparry carbonates of iron, or spathose iron ores,
usually contain a large proportion of oxide of manganese in mixture with
oxides of iron. Such ores when smelted in a blast furnace or cupola with
charcoal or other fuel yield a species of pig iron which is essentially. an alloy,
of iron and manganese, containing also carbon. Such pig iron is termed
spathose pig iron, or steel pig, or, when white and regularly crystallized,
spiegel eisen," that is, "looking-glass iron," from the brilliant facets it
exhibits when fractured. Franklinite pig iron is also an alloy of iron and
manganese, containing also carbon, and is one of the varieties of cast iron
which I employ in carrying my Invention into effect.
<
In the manufacture of cast steel a portion of spathose pig iron or Frank-
linite iron is frequently added to the mixture of materials which it is intended
to melt into cast steel, for the purpose of improving the quality of the cast
steel produced. To prepare the spathose pig iron. for this purpose it is broken
up into lumps of a size convenient for introducing into the melting pot or
crucible along with the materials, or mixture of materials, about to be melted
into cast steel.
Now, I have discovered that when the grey, white, or mottled spathose pig
iron, or steel pig, or Franklinite iron is previously prepared by the process of
hot granulation. herein-after described, and is used with oxide of manganese,
the said oxide of manganese being either mixed with or added to the
granulated spathose iron, the said spathose pig iron affords better results
when added to the materials or mixture of materials which it is intended to
melt into cast steel, than it yields when employed without hot. granulation.
The spathose pig iron or steel pig which I prefer to use is the grey, mottled,
or white steel pig, but not the white crystalline variety, or true "spiegel eisen,"
which I do not find improved by hot granulation. I prefer to employ spathose
pig iron or steel pig which has been smelted wholly. with charcoal fuel; but
excellent results may also be obtained by the. hot granulation of spathose pig
iron or steel pig, smelted either with a mixture of coke and, charcoal fuel, or
wholly with coke fuel when the fuel employed is of. good quality and tolerably
free from sulphur.

page_text: The process of hot granulation by which I prepare the spathose pig iron or
steel pig for my purpose is conducted as follows:-I break the spathose pig
iron or steel pig into lumps or pieces of from ten to forty pounds weight each,
as convenience may suggest. I heat these lumps of steel pig to a heat some-
what short of their melting point, and I then subject the heated lumps to the
action of hammers, rollers, crushers, or stampers, 'in order to reduce them
whilst rendered friable by their heat to a coarse metallic gravel or powder.
When thus stamped, crushed, or pulverized whilst in a heated state, I mix the
granulated spathose pig iron when cold with oxide of manganese, adding
about one ounce of oxide of manganese to each pound of granulated spathose
pig iron or steel pig. When thus prepared, the spathose pig iron or steel pig
is ready for use. I wish it to be observed that I do not claim the granulation
of spathose pig iron by running the said pig iron when melted into water.
The hot granulated spathose pig iron may be added to the materials, or
mixture of materials, intended to be melted into cast steel, either mixed or
unmixed with oxide of manganese, for the latter may be added separately;
but I prefer to mix the said oxide of manganese with the granulated spathose
pig iron, as it affords better results.
I do not confine myself to the proportion of oxide of manganese to
granulated spathose pig iron or steel pig which I have herein-before set
down, for the relative proportion of the oxide of manganese to the granulated
spathose pig iron may be varied at pleasure; but I have found the proportions
I have given afford excellent results.
I
prepare the lumps of spathose pig iron by placing them in an air furnace,
or in a reverberatory furnace, wherein I heat the said lumps of spathose pig
iron until they have reached a temperature a little short of their melting point,
whereby the said lumps are rendered soft and friable. I granulate the said
heated lumps of spathose pig iron by placing them in an iron mortar, and
beating upon the said heated lumps with heavy iron pestles until the said
heated lumps of spathose pig iron are reduced to a granular state. The
heated lumps of spathose pig iron may be granulated by the action of
machinery in various ways; but in practice I find that the method of
granulation I have herein-before described is both convenient and effective.
Having ascertained the nature of my Invention, and the manner in which
the same is to be performed, I wish it to be understood that I claim as my
Invention, the improvement or improvements in the manufacture of cast steel
herein-before described, that is to say, adding to the materials, or mixture of
materials, which when melted produces cast steel, spathose pig iron or steel

page_text: pig which has been granulated by the process of hot granulation herein
described, whether the said hot granulated spathose pig iron or steel pig be
used mixed with oxide of manganese, or the said oxide of manganese be
added separately.
In witness whereof, I, the said Robert Mushet, have hereunto set my
hand and seal, this Eleventh day of May, in the year of our Lord
One thousand eight hundred and sixty-three.
Witnesses,
EDWP. M. MUSHET,
Coleford, Gloucestershire.
B. MUSHET,
Coleford, Gloucestershire.
ROBT. MUSHET. (L.8.)