IMPROVEMENTS IN THE MANU- FACTURE OF CAST STEEL
Year: 1859

page_text: *LETTERS PATENT to Robert Mushet; of Coleford, in the County of Glou-
cester, Metallurgist, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF CAST STEEL."
Sealed the 28th June 1859, and dated the 17th January 1859.
PROVISIONAL SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the 17th
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," to be as follows:-
My Invention consists; firstly, in producing cast steel from scrap steel, bar
steel, or blister steel, melted in 'the usual manner in clay pots or crucibles,
and combined in the melting pots with deoxydized iron ore and a triple com-
pound, consisting of or containing iron, carbon, and metallic manganese, and,
secondly, in producing cast steel from wrought or malleable iron melted with
carbonaceous matter, and combined in the melting pots with deoxydized iron
ore, and a triple compound, containing iron, carbon, and metallic manganese.
The triple compound or material which I prefer to use is, the white crystalline
pig or cast iron metal, made from smelting with coal, coke, or charcoal fuel.
the sparry carbonates of iron, termed spathose iron ores, or such other ores of_

page_text: iron as contain besides iron a considerable quantity of manganese; but the
triple compound of iron; carbon, and metallic manganese may, however, be
produced or made in any other manner which may be found to be more con-
venient or economical. The deoxydized iron ore may be prepared by heating
iron ores or oxides of iron in close brick chambers or vessels in contact with
charcoal or other carbonaceous substances, or such gases as reduce or
deoxidize heated oxide of iron, until the ores or oxides of iron shall have
been deprived or nearly deprived of their oxygen. The proportions of these
materials to be combined to produce cast steel vary
with the nature of the
substances to be operated upon, but I have found that the following pro-
portions produce good results in practice.
Firstly, when the iron ore is completely deoxidized, I mix it with the scrap
steel, bar steel, or blister steel, or mixtures of wrought iron with carbonaceous
matter in various proportions, observing, however, that a mixture of one part
of the deoxydized iron ore with from one to four parts by weight of any of
these substances gives an excellent result, and that the larger the proportion
of deoxydized iron ore used in the mixture, the sounder and more ductile
will be the resulting cast steel. To every hundred parts by weight of such
mixture, I add in the melting pots or crucibles from two to twenty parts by
weight of the triple compound of iron, carbon, and metallic manganese, in
order to obtain all the qualities of cast steel ordinarily required in commerce,
observing that the degree of hardness of the steel thus obtained will be
regulated by the proportion of the said triple compound combined with it,
and that the hardness of the steel will be increased in proportion as the
quantity of the triple compound combined with it is increased.
Secondly, when the iron ore is nearly but not wholly deoxydized, I mix
with it'a quantity of charcoal, amounting, by weight, to from one to five per
centum of the weight of the deoxydized iron ore to be operated upon,
according as the iron ore has been more or less nearly deoxydized, and I
then proceed to combine it with the steel or iron, and with the triple com-
pound of iron, carbon, and metallic manganese in the manner I have already
described. The materials may be mixed together in the cold state, placed in
the melting pots, and melted into steel; or the steel and deoxydized iron ore,
or the wrought iron and carbonaceous matter and the deoxydized iron ore,
may be first melted, and the triple compound of iron, carbon, and metallic
manganese may then be added, also in a molten or fluid state; or the mixture
and combination of the materials may be effected in the melting pots in any
convenient manner, in order to form by their union melted cast steel.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed'
by the said Robert Mushet in the Great Seal Patent Office on the
14th 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 Seventeenth 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
me, the said Robert Mushet, Her special licence that I, the said Robert
Mushet, my executors, administrators, and assigns,. or such others as I, tho
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 "IMPROVE-
MENTS IN THE MANUFACTURE OF CAST STEEL," 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
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 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 fol-
Jowing statement thereof, that is to say:-
My Invention consists, firstly, in manufacturing cast steel from scrap
steel, bar steel, or blister steel melted in the usual manner in clay pots or
crucibles, and combined in the melting pots with deoxydized iron ore and a
triple compound consisting of or containing iron, carbon and manganese; and,
secondly, in producing cast steel from wrought or malleable iron melted with
carbonaceous matter, and combined in the melting pots with deoxydized iron
ore and a triple compound consisting of or containing iron, carbon, and metallic
manganese. The triple compound or material which I prefer to use is the
white crystalline pig or cast-iron metal known in Rhenish Prussia by the name
of spiegel eisen, which said spiegel eisen is made by smelting with coal, coke,
or charcoal fuel, the sparry carbonates of iron termed spathose iron ore, or such

page_text: other ores of iron as contain besides iron a considerable quantity of manganese;
but the triple compound of iron, carbon, and metallic manganese may be
produced or made in any other manner which may be found to be convenient
and economical. The deoxydized iron ore which I employ may be prepared
by beating iron ores or oxydes of iron in close brick chambers or vessels, in
contact with charcoal or other carbonaceous substances, which will reduce or
deoxydize heated oxyde of iron, the ores or oxydes of iron being thus treated
until they have been deprived or nearly deprived of their oxygen. The precise
proportions in which the materials employed must be combined to produce
cast steel varies with the particular nature or state of the said materials, but I
have found that the following proportions produce good results in practice
when the materials are of average quality and in the states or conditions
described.
When the iron ore is completely deoxydized, I mix it with the scrap steel,*
bar steel, or blister steel, or mixtures of wrought or malleable iron with
carbonaceous matter in various proportions, that is to say :-From one part by
weight of carbonaceous matter to two hundred parts by weight of wrought or
malleable iron to five parts by weight of carbonaceous matter to two hundred
parts by weight of wrought or malleable iron, observing, however, that a
mixture of one part by weight of the deoxydized iron ore with from one to
four parts by weight of any of the kinds of steel described or of the mixture
of wrought iron and carbonaceous matter, gives excellent results, and that the
larger the proportion of deoxydized iron ore used in the mixture the sounder
and more ductile will be the resulting cast steel. To every hundred parts by
weight of such a mixture I add in the melting pot or crucible from two to
twenty parts by weight of the triple compound of iron, carbon, and metallic
manganese. By varying the proportion of the said triple compound between
these extremes all the qualities of cast steel ordinarily required in commerce
may be obtained, the degree of hardness of the steel produced will be deter-
mined by the proportion of the said triple compound combined with it, the
hardness of the steel being increased in proportion as the quantity of the triple
compound combined with it is increased.
When the iron ore is nearly but not wholly deoxydized, I mix with it a
quantity of charcoal, amounting by weight to from one to five per centum of the
weight of the deoxydized iron ore to be operated upon according as the iron
ore has been more or less nearly deoxydized, and I then proceed to combine it
with the steel or iron, and with the triple compound of iron, carbon, and netallic
manganese by melting in the manner I have already described. The materials
may be mixed together in the cold state, placed in the melting pots and melted

page_text: into steel, or the steel and deoxydized iron ore or the wrought iron carbonaceous
matter and deoxydized iron ore may be first melted, and the triple compound of
iron, carbon, and metallic manganese may then be added, also in a molten or
fluid state; or the mixture or combination of the materials may be effected in
the melting pots in any convenient manner, in order to form by their union
melted cast steel. I prepare scrap steel, bar steel, or blister steel for my
process by breaking or cutting these materials into small pieces of a convenient
size for packing into the melting pots or crucibles exactly in the manner
ordinarily practised by manufacturers of cast steel. I prepare wrought or
malleable iron for my process by cutting it up with shears, either when heated
or when cold, into small pieces of half a pound weight each, and as much
smaller as they can be conveniently made consistently with the proper economy
of time and labor in the process of cutting up the said malleable iron. I
prepare the triple compound of iron, carbon, and manganese, or "spiegel eisen".
as it is termed, by breaking it up into small fragments not exceeeding in size
a hen's egg, and as much smaller as they may happen to become during the
breaking up. I break up the said compound by beating lumps of it upon a
block or plate of iron with a heavy hammer, and which operation is greatly
facilitated by previously heating the lumps of "spiegel eisen " to a red heat,
and then cooling them suddenly in water, which treatment causes the said
lumps to crack and become full of fissures, or the "spiegel eisen " may be
granulated by melting it and running it into water; but as the said triple
compound parts with a portion of its manganese every time it is melted, I prefer
to melt it or remelt it as seldom as possible. The deoxydised iron ore I prepare
as follows: I select the purest hematite iron ores or the specular and
magnetic iron ores or the purest spathose iron ores, and I deoxydize them by
carbonaceous matter by subjecting them to a heat ranging from eighty to
ninety degrees of Wedgewood's pyrometric scale when closely confined in a
brick or stone chamber or chest, such, for instance, as those used for con-
verting bar iron into blistered steel. I continue the process until the whole or
nearly the whole of the oxygen has been removed from the iron ores by the
union of the said oxygen with the surrounding carbonaceous matter. But it
is not necessary to prolong this process after the removal of the oxygen from
the iron ore has been effected, so as to cause the deoxydized iron ore to take
up carbon or combine therewith. I also find it convenient to break the lumps
of iron ore which are to be deoxydized into small pieces of the size of a hen's
egg and under that size, and I sometimes crush the iron ore to the state of
gravel or powder, and mix it or stratify it with charcoal or other carbonaceous
matter in the cementing or deoxydizing chest or chamber.
S

page_text: When the lumps of iron ore are deoxydized, or nearly so, that is to say, when
they are deprived or nearly deprived of all their oxygen, and after they have
cooled down, I subject them to the action of stamps, rollers, edge runners, or
any other suitable machinery until they are reduced to the state of coarse
gravel or powder. Now, the quartz and other earthy. impurities which are
more or less associated with nearly all ores of iron, and which are found
adhering to or inclosed in the lumps or masses of deoxydized iron ore, are for
the most part beaten or pulverized into a fine powder during the process of
crushing the deoxydized iron ore to coarse gravel or powder, and I now
winnow out or drive off the quartz and other light earthy impurities, such as
lime, clay, or silica, by letting the pulverized deoxydized iron ore fall from a
sieve or riddle in a thin stream exposed to the action of the wind, or of
artificial currents of air directed against the falling stream of pulverized
deoxydized iron ore, and I thus obtain the deoxydized iron ore in a nearly
pure metallic state, and almost free from the earthy matters found mixed with
the iron ore, and adhering to it when deoxydized. Or I remove the earthy
matters in any other convenient manner, but it is to be observed that I do not
claim as of my said Invention any method for thus winnowing or cleansing
deoxydized iron ore, neither do I claim as of my said Invention any method or
process for deoxydizing iron ores, which may be done in any convenient
manner. The melting pots or crucibles which I employ, and the melting
furnaces in which the said pots are placed, and wherein they are heated, are
such as are ordinarily employed by manufacturers of cast steel.
Having now described the general nature of my Invention, I will now pro-
ceed to explain the particular manner in which I carry my Invention into
effect. When the iron ore has been completely deoxydized, I proceed as
follows:-
To twelve pounds of completely deoxydized iron ore prepared as I have
herein-before described, I add twenty-four pounds of scrap steel, bar steel, or
blister steel, or twenty-four pounds of any mixtures of these materials, and
about five pounds of the triple compound of iron, carbon, and manganese. I
introduce these substances into a melting pot or crucible placed in a steel
melting furnace, and I heat them therein until the said substances are melted.
I then withdraw the melting pot from the furnace, and pour the steel into an
ingot or other mould in the usual manner. I do not confine myself to the
above proportions, as the proportions must be varied according to the varying
nature of the materials operated upon, but it is to be observed that by
increasing or diminishing the relative proportion of the said triple compound
added to the said scrap, bar, or blister steel, and to the said completely

page_text: deoxydized iron ore, the hardness of the steel produced is increased or
diminished, so that by regulating the relative quantity or proportion of the said
triple compound added to the other materials, whilst the relative quantities of
proportions of the steel and deoxydized iron ore remain the same, steel of any
degree of hardness or softness required in commerce may be readily obtained..
When the iron ore has been nearly but not completely deoxydized, I add to
twelve pounds of such partially deoxydized iron ore, prepared as herein-before
described, about six ounces of charcoal, reduced or crushed to the state of
coarse powder, and I mix these substances together. To the mixture thus
obtained, I add twenty-four pounds of scrap, bar, or blister steel, and four
pounds of the triple compound of iron, carbon, and manganese. I introduce
these substances into a melting pot or crucible placed in a steel melting
furnace, and I heat them therein until the said substances are melted. I
then withdraw the melting pot from the furnace, and pour the steel into an
ingot or other mould in the usual manner.
I do not confine myself to the above proportions, as the proportions must be
varied according to the particular nature of the materials operated upon, but
it is to be observed that by increasing or diminishing the relative proportion
of the said triple compound added to the said scrap, bar, or blister steel, and
to the said partially deoxydized iron ore mixed with charcoal, the hardness of
the steel produced is increased or diminished, so that by varying the relative
proportion or quantity of the said triple compound added to the other
materials, whilst the relative proportions or quantities of the said materials;
namely, the scrap, bar, or blister steel, the partially deoxydized iron ore and
the charcoal remain the same, steel of any degree of hardness or softness
required in commerce may be readily obtained. Likewise by increasing or
diminishing the relative quantity or proportion of the charcoal to the other
materials, the hardness of the steel produced may be increased or diminished;
the relative quantities or proportions of the other materials, namely, the scrap;
bar, or blister steel, the partially deoxydized iron ore, and the triple compound
of iron, carbon, and manganese remaining the same. When, instead of scrap,
bar, or blister steel, I employ a mixture of wrought or malleable iron and
charcoal, I proceed as follows:-
་
To nine pounds of completely deoxydized iron ore, prepared as I have
herein-before described, I add twenty-seven pounds of wrought or malleable
iron, four ounces of charcoal, and about five pounds of the triple compound of
iron, carbon, and manganese. I introduce these substances into a melting
pot or crucible placed in a steel melting furnace, and I heat them therein
until the said substances are melted into steel. I then withdraw the melting

page_text: pot from the furnace, and pour the steel into an ingot or other mould in the
usual manner. I do not confine myself to the proportions described, as the
proportions must be varied according to the nature of the materials operated
upon, but it is to be observed that by increasing or diminishing the relative
proportion of the said triple compound added to the said wrought or malleable
iron, and to the said completely deoxydized iron ore, the hardness of the steel
produced is increased or diminished, so that by varying the relative quantity
or proportion of the said triple compound added to the other materials, whilst
the relative quantities or proportions of the wrought or malleable iron and
deoxydized iron ore remain the same, steel of any degree of hardness or
softness required in commerce may be readily obtained.
When the iron ore has been nearly but not completely deoxydized, I add to
nine pounds of such partially deoxydized iron ore prepared as I have herein-
before described, about twelve ounces of charcoal reduced or crushed to the
state of coarse powder, and I mix these substances together. To the mixture
thus obtained I add twenty-seven pounds of wrought or malleable iron,
and four pounds of the triple compound of iron, carbon, and manganese.
I
introduce these substances into a melting pot or crucible, placed in a steel
melting furnace, and I heat them therein until the said substances are melted
into steel; I then withdraw the melting pot from the furnace, and pour the
steel into an ingot or other mould in the usual manner.
I do not confine myself to the above proportions, which must be varied
according to the nature of the materials operated upon, but it is to be observed
that by increasing or diminishing the relative proportion of the said triple
compound added to the said wrought or malleable iron, and to the said
partially deoxydized iron ore mixed with charcoal, the hardness of the steel
produced is increased or diminished, so that by varying the relative proportion
or quantity of the said triple compound added to the other materials, whilst
the relative proportions or quantities of the said materials, namely, the wrought
or malleable iron, the partially deoxydized iron ore, and the charcoal remain
the same, steel of any degree of hardness or softness required in commerce
may be readily obtained. Likewise by increasing or diminishing the relative
quantity or proportions of the charcoal to the other materials, the hardness of
the steel produced may be increased or diminished, the relative quantities or
proportions of the other materials, namely, the wrought or malleable iron, the
partially deoxydized iron ore, and the triple compound of iron, carbon, and
manganese remaining the same.
In place of adding the triple compound of iron, carbon, and manganese to
the scrap, bar, or blister steel, and the wholly or partially deoxydized iron ore,

page_text: or to the wrought or malleable iron and charcoal, and the wholly or partially
deoxydized iron ore, and introducing these materials together into the melting
pot or crucible, I sometimes introduce the said mixture of scrap, bar, or blister
steel, and wholly or partially deoxydized iron ore, or of wrought or malleable
iron, charcoal, and wholly or partially deoxydized iron ore into the melting
pots, placed in melting furnaces, and heat them therein, until they are in a
melted state, and I then pour into each melting pot the requisite quantity of
the said triple compound, also in a liquid melted state; I then withdraw the
melting pots from the furnaces, and pour the steel into ingot or other moulds
in the ordinary manner.
In practice I find the following method of adding the melted triple com-
pound of iron, carbon, and manganese to the melted steel in the melting pots
very convenient. The quantity of the triple compound of iron, carbon, and
manganese required for each pot of cast steel is weighed, and placed in a
small pot or crucible. This small pot is then set upon the lid of, the melting
pot about half an hour before the latter is to be withdrawn from the furnace.
The triple compound in the small pot is soon melted, and the said small pot is
then lifted in a pair of small tongs, the lid of the larger melting pot is put
aside, and the contents of the small pot are poured into the melting pot, and
mixed with the melted steel therein.
Having thus particularly ascertained and described the nature of my said
Invention of improvements in the manufacture of cast steel, and the manner
in which the same is to be performed, I hereby declare that the essence of my
Invention consists,―
First, in manufacturing cast steel by melting and combining scrap steel, bar
steel, or blister steel, or any mixtures of these with wholly deoxydized iron ore,
and a triple compound of iron, carbon, and manganese.
Second, in manufacturing cast steel by melting and combining scrap steel,
bar steel, or blister steel, or any mixtures of these with partially deoxydized
iron ore mixed with charcoal or other carbonaceous matter, and a triple
compound of iron, carbon, and manganese.
Third, in manufacturing cast steel by melting and combining wrought
or malleable iron, and wholly deoxydized iron ore mixed with charcoal or
other carbonaceous matter, and a triple compound of iron, carbon, and
manganese.
Fourth, in manufacturing cast steel by melting and combining wrought or
malleable iron, and partially deoxydized iron ore mixed with charcoal or other
carbonaceous matter, and a triple compound of iron, carbon, and manganese,
in order that in each case when the described substances have been introduced

page_text: into and heated in melting pots until the said substances are melted and
converted into steel, an improved quality of cast steel may be obtained from
the union and combination of the said triple compound of iron, carbon, and
manganese with the other materials.
In witness whereof, I, the said Robert Mushet, have hereunto set my
band and seal, this Eighteenth day of June, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witness,
EDw". M. MUSHET,
Coleford,
Gloucestershire.
ROBT. MUSHET. (L.S.)