AN IMPROVEMENT IN THE MANUFACTURE OF CAST STEEL
Year: 1859

page_text: LETTERS PATENT to Robert Mushet, of Coleford, in the County of
Gloucester, Metallurgist, for the Invention of "AN IMPROVEMENT IN
THE MANUFACTURE OF CAST STEEL."
Sealed the 9th August 1859, and dated the 24th February 1859.
PROVISIONAL SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the
24th February 1859.
I, ROBERT MUSHET, of Coleford, in the County of Gloucester, Metallurgist,
do hereby declare the nature of the said Invention for "AN IMPROVEMENT
IN THE MANUFACTURE OF CAST STEEL," to be as follows:-
My said Invention consists in adding to cast steel, and melting and combining
therewith, a metallic compound of tungsten, iron, and manganese. I prefer to
prepare the said metallic compound of tungsten, iron, and manganese, by
deoxydizing and metallizing the native tungstate of iron and manganese called
wolfram or wolfram ore, by heating it with charcoal or other deoxydizing agent
in retorts or close vessels or chambers."
The furnace used for converting bars of iron into steel may be employed for
this purpose. After the wolfram has been reduced or metallized, I crush or
break the product to small pieces, and by a blast of air or otherwise I remove as
much as possible the earthy impurities with which it may be contaminated.
I add this metallic compound of tungsten, iron, and manganese to steel in the pro-
portions herein-after described, and melt the steel and the said metallic compound;

page_text: together in a melting pot or crucible. The melting pot and furnace may be
of the kind ordinarily employed for melting steel. When perfectly melted I
pour the steel into ingot or other moulds. The ingots may be reheated and
hammered or rolled into bars, rods, or sheets in the usual manner. The
hardness of the steel manufactured according to my Invention depends upon
the relative quantity of the compound of tungsten, iron, and manganese which
has been melted with it. I have found in practice that a quantity varying
from two ounces to ten ponnds of the compound of tungsten, iron, and
manganese melted with forty pounds of steel produce all the different degrees
of hardness ordinarily required in steel for commercial purposes. I do not,
however, limit myself to any particular proportions, neither do I confine
myself to the use of a metallic compound of tungsten, iron, and manganese
made from wolfram, as other methods of making the said metallic
compound may be resorted to. The metallic compound thus prepared by
deoxydizing wolfram varies in its constituent proportions of tungsten, iron, and
manganese, according to the nature of the wolfram from which it has been
prepared; but it may be composed on an average of about seventy equal parts
by weight of tungsten, fifteen such equal parts by weight of iron, and eight
such equal parts by weight of manganese; but I by no means limit myself to
the use of a compound consisting of tungsten, iron, and manganese combined
in these proportions.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Mushet in the Great Seal Patent Office on the
18th August 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT 2
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 February, 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 1, 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

page_text: 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 IN THE MANUFACTURE OF CAST STEEL," upon the con-
dition (amongst others) at I, the said Robert Mushet, my executors or
administrators, by an instrument in writing under my, or their, or one
of their hands and scals, should particularly describe and ascertain the
nature of the said Invention, and in what mauner 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
following statement thereof, that is to say:-
My said Invention consists in adding to cast steel and combining therewith
a metallic compound of tungsten, iron, and manganese. I prefer to prepare
the said metallic compound of tungsten, iron, and manganese by deoxidizing
and metallizing the native tungstate of iron and manganese called wolfram or
wolfram ore by beating it with charcoal or other deoxidizing agent in retorts
or close vessels or chambers. The furnace used for converting bars of iron
into steet may be employed for this purpose. After the wolfram has been
reduced or metallized, I crush or break the product to small pieces, and by a
blast of air or otherwise I remove as much as possible the earthy impurities
with which it may be contaminated. I add this metallic compound of
tungsten, iron, and manganese to steel in the proportions herein-after described
and melt the steel and the said metallic compound together in a belting pot
or crucible. The melting pot and furnace may be of the kind dinarily
employed for melting steel. When perfectly melted, I pour the steel into
iugot or other moulds. The ingots may be reheated and hammered, or rolled
into bars, rods, or sheets in the usual manner. The hardness of the steel
manufactured according to my. Invention depends upon the relative quantity of
the compound of tungsten, iron, and manganese which has been melted with
it. I have found in practice that a quantity varying from two ounces to two
pounds of the compound of tungsten, iron, and manganese, melted with forty
pounds of steel, produce all the different degrees of hardness ordinarily required
in steel for commercial purposes. I do not, however, limit myself to any
particular proportions, neither do I confine myself to the use of a metallic com-
pound of tungsten, iron, and manganese made from wolfram, as other methods
of making the said metallic compound may be resorted to. The metallic
•

page_text: compound thus prepared by deoxidizing wolfram varies in its constituent
proportions of tungsten, iron, and manganese, according to the nature of the
wolfram from which it has been prepared, but it may be composed on an
average of about seventy equal parts by weight of tungsten, fifteen such.equal
parts by weight of. iron, and eight such equal parts by weight of manganese ;
.but I by no means limit myself to the use of a compound consisting of tungsten,
iron, and manganese combined in these proportions.
•
Having thus stated generally the nature of my Invention, I will proceed to
describe in detail the best method with which I am acquainted of carrying
my Invention into effect.
31
The manner in which I prefer to prepare a metallic alloy of tungsten, iron,
and manganese is by reducing or deoxidizing wolfram, and for this purpose
I select the purest wolfram and such as contains a large per-centage of
tungsten. The furnace I employ for reducing or deoxidizing the wolfram is
an ordinary steel converting furnace furnished with converting chests or pots
in the usual manner, but I am careful to construct the said furnace of the
most refractory fire-stone or fire-bricks, in order to enable the said furnace to
withstand the intense heat which I apply in order to deoxodize or reduce the
wolfram. I prepare the wolfram by breaking it, if in lumps, into pieces of
the size of a walnut and under, and I separate the broken wolfram into from
three to four different sizes by means of sieves or riddles, and which sizes I
term respectively "rough," "middle sized," "small," and "dust" ore. On
the floor of the converting chest or pot I place a layer of coarsely pulverized
charcoal or other carbonaceous matter, such, for instance, as charred peat or
.lignite, about four inches in thickness, and over this a layer of "rough ore
.three inches in thickness. Upon this I again lay a bed of charcoal four
inches thick, and upon this I place a layer of "middle sized" ore three inches
in thickness. I again cover this with charcoal to the thickness of four inches,
and place upon this charcoal a layer of "small ore" three inches thick, which
I then cover with a layer of .charcoal four inches thick, and place upon this
a layer of "dust ore" three inches in thickness. If the chest or pot be not
'now full, I add another layer of charcoal, and another layer of "middle sized"
'ore, and finish the charging of the chest by covering the whole with charcoal
to the depth of four or five inches. I then construct a rough, brick arch
.coated with loam over the top layer of charcoal, and having closed the furnace
carefully, I proceed to heat it in the manner usually practised by steel con-
*verters in converting bar iron into steel. But it must be observed that I do
not limit myself to employ merely that degree of heat which is sufficient for
converting bar iron into steel; on the contrary, I heat the furnace to

page_text: the utmost extent which the brick or stone materials of which the said
deoxodizing furnace is constructed can safely withstand, that is to say, to a
temperature ranging from 100 degrees to 140 degrees of Wedgewood's
pyrometic scale, and which temperature is to be maintained for from seventy-
two to ninety-six hours, according to the size of the deoxodizing furnace, and
the quantity of wolfrám contained in it; that is to say, if the furnace contains
from five to seven tons of wolfram, it will be sufficient to continue the intense
white heat for seventy-two hours, and if the furnace contains from seven to
twelve tons of wolfram I prefer to continue the intense heat for about ninety-
six hours. I then allow the furnace to cool down, and when cold I
open it
and withdraw the deoxidized metallized wolfram and the charcoal which
remains, and I separate the charcoal from the said metallized wolfram, which
is now an alloy of tungsten, iron, and manganese, by winnowing the said
charcoal away from the alloy by means of a fan, blast, or other current of air
directed against it; or the charcoal may be separated by washing it away
from the metallized wolfram with a stream of water, in which case I subse-
quently dry the said metallized wolfram upon a stove. Having thus obtained
a metallic compound of tungsten, iron, and manganese, I stamp, crush, or
grind the said compound, and should it contain, as is sometimes the case,
quartz or other light impurities, these may be either separated from the said
compound by winnowing it before a blast or current of air, or by washing it
with a stream of water, and then drying the purified metallic residuum of
tungsten, iron, and manganese.
When thus prepared, the metallic compound of tungsten, iron, and
manganese is ready for my process.
I have found in practice that the following proportions afford good results:-
Firstly, to forty pounds of blister steel I add eight ounces of the prepared.
metallic.compound of tungsten, iron, and manganese, and I introduce the
blister steel and the said compound into a melting pot or crucible placed in
an ordinary steel melting furnace, and I heat these substances therein_until
the steel is melted and the metallic compound is alloyed with the said steel;
I then withdraw the melting pot and pour the steel into an ingot or other
mould. I sometimes combine the compound of tungsten, iron, and man-
ganese with pitch or other carbonaceous matter before adding the said com-
pound to the steel, and for this purpose I melt in a pitch pot or kettle a
certain weight of pitch, and when inelted I stir into it and mix with it a
quantity of the said metallic compound twice the weight of the said pitch,
and I then pour out the mixture upon a cold flagstone, well moistened to
prevent the said mixture from adhering to the said stone, and when the com-

page_text: pound thus obtained is cold I break it up into pieces of the size of a walnut, and
under ready for use. Secondly, to forty pounds of good charcoal bar iron, such,
for instance, as the Swedish bar iron, I add from six to eight ounces of charcoal,
and one pound of the metallic compound of tungsten, iron, and manganese,
prepared as I have herein-before described. I introduce these substances
into a melting pot or crucible placed in an ordinary steel melting furnace, and
I-heat them therein until the bar iron and charcoal are melted into steel; and
the said metallic compound is likewise melted and alloyed with the said steel.
I then withdraw the melting pot from the furnace, and pour the steel into an
ingot mould or into any other mould which it may be desirable to employ. I
sometimes mix the prepared metallic compound with pitch or other carbona-
ceous matter in the manner I have herein-before described, and I then add
the mixture thus obtained to the bar iron and charcoal, and introduce these
substances together into the melting pot.
But I do not claim the addition of carbonaceous matter to the metallic
compound of tungsten, iron, and manganese as part of my said Invention,
neither is it essential to its success. When mixtures of pig iron and malleable
iron, or mixtures of granular cast iron and iron ore or oxide of iron, or when
any other mixtures of materials are employed, which when introduced into a
melting pot or crucible placed in a melting furnace, and heated therein until
they are melted, are converted into steel, then in each instance I add to forty
'pounds of any of these said mixtures from eight ounces to one pound of the
prepared metallic compound of tungsten, iron, and manganese, and proceed as
I have herein-before described, when I employ blister steel or malleable
iron and charcoal to melt into cast steel.
I do not confine myself to the. précise proportions which I have here set
down, as the proportions may be varied without departing from the nature of
my Invention, but I wish it to be understood that by increasing or diminishing
the relative quantity or proportion of the metallic compound of tungsten, iron,
and manganese, added to and melted with the steel, the hardness of the
said steel will be increased or diminished in a corresponding manner, so that
by varying the relative quantity or proportion of the said compound added to
and melted with the steel, the hardness of the said steel may be increased or
diminished, as may be required.
Having thus described the nature of my Invention and the manner in
which I carry the said Invention into effect, I hereby declare that the
essence of my Invention consists in adding to cast steel and combining there-
with a metallic compound of tungsten, iron, and manganese, which said
metallic compound I prefer to prepare by deoxidizing or reducing wolfram or

page_text: tungstate of iron and manganese with charcoal in a converting furnace, in the
manner I have berein-before described; but I do not limit myself to a metallic
compound of tungsten, iron, and manganese thus prepared, for it may be
prepared in any convenient economical manner.
In witness whereof, I, the said Robert Mushet, have hereunto set my
hand and seal, this Eighth day of August, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witnesses,
EDWP. M. MUSIET,
Coleford, Gloucestershire.
BROOKLYN MUSHET,
Coleford, Gloucestershire.
ROBT. MUSHET. (L.S.)