IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL
Year: 1857

page_text: LETTERS PATENT to Robert Mushet, of Coleford, in the County of
Gloucester, Metallurgist, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF CAST STEEL."
Sealed the 27th November 1857, and dated the 18th June 1857.
PROVISIONAL SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the 13th
June 1857.
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 said Invention consists of combining metallic manganese with cast
steel, in order to improve its quality, and in combining metallic manganese
with bar or wrought iron, so as to produce cast steel without any additional
admixture of carbonaceous matter or cast iron to the compound. But I do
not here claim the combination of metallic manganese with partially decar-
bonised purified cast iron, for the purpose of converting it into steel of an
improved quality, as already set forth in Letters Patent granted to me, and
dated 2nd Sept 1856; neither do I claim the use of carburet of manganese
for improving cast steel, but merely the combination of metallic manganese
with cast steel.
The metallic manganese may be obtained by melting oxyde of manganese in
close vessels or chambers, with fluor spar, soda, and common salt, or in any
other convenient and economical manner; but I do not here claim any
method of procuring or producing the metallic manganese.

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 12th
December 1857.
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 Thirteenth day of June, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth 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 "IMPROVEMENTS 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 my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
When cast steel has been melted from any ordinary materials, such as bar,
scrap, or blister steel, bar iron, and carbonaceous matters, mixtures of bar or
wrought iron and cast iron, mixtures of cast iron and oxydes of iron, deoxydized
iron ores, or any mixtures of these one with the other; or, when cast steel is
re-melted from decarbonized or partially decarbonized cast iron, which has been
purified by forcing air through it whilst in a fluid molten state; or, when cast
steel has been melted from any other usual or ordinary materials, I find that
the quality of the steel is greatly improved by adding to it a portion of metallic
. manganese. The quantity or proportion of metallic manganese to be thus
added to the melted or nearly melted cast steel may be varied as circumstances
require, (that is to say,) according to the nature of cast steel used and the effect

page_text: intended to be produced. For example, when a mild quality of cast steel is to
be produced, I add a quantity of the said metallic manganese, amounting
to about one-hundreth part, that is, one per cent. by weight of the melted
or nearly melted cast steel. When a quality of cast steel of medium hardness
and "body," as it is technically termed, is to be produced, I add a quantity of
the said metallic manganese, from one-fiftieth to one-thirty-third, that is, from
two to three per cent. by weight of the melted or nearly melted cast steel.
When a quality of cast steel possessing great hardness and "body" is to
be produced, I add a quantity of the said metallic manganese, amounting
to about one-twentieth, that is, five per cent. of the melted or nearly melted
cast steel.
I have found, however, that it is sufficient to add a quantity of the said
metallic manganese amounting, by weight, from about one-hundreth to about
one-twentieth of the weight, (that is to say,) from one to five per centum of the
melted or nearly melted cast steel; also when bar or wrought iron alone, and
without any mixture of carbonaceous matters or cast iron, has been melted,
I find that the combination of metallic manganese therewith converts the
mixture into excellent cast steel without any further addition of carbonaceous
matter or cast iron.
The quantity or proportion of metallic manganese to be thus added to the
melted or nearly melted bar or wrought iron may be varied as circumstances
require, (that is to say,) according to the nature of the bar iron or wrought
iron used, and the effect intended to be produced. I have found, however, that
it is sufficient to add a quantitiy of the said metallic manganese, amounting by
weight from about one-hundreth to about one-tenth of the weight, (that is to
say,) from one to ten per centum of the melted or nearly melted bar or wrought
iron.
The metallic manganese may be obtained by melting.oxyde of manganese in
close vessels or chambers, with fluor spar, soda, and common salt; or it may
be prepared in any other manner which may be found to be convenient and
economical; but I do not claim as of my Invention the manner or method
by which the metallic manganese is obtained or produced.
I now proceed to describe the manner in which my Invention may be
practised: When the cast steel or the bar of wrought iron to be operated upon
has been heated in a melting pot, vessel, or chamber, or in any other convenient
manner, so as to have become fluid or nearly so, I enclose the portion of
metallic manganese which is to be added to the mixture in a piece of thin
sheet iron, and then drop it into the fluid or semi-fluid steel contained in the
said melting pot, vessel, or chamber; and I then, if necessary, continue to heat

page_text: the mixture in the ordinary manner until it has becomic perfectly fluid, and I
then pour it into ingot moulds in the usual way practised by steel makers.
The metallic manganese may also be added and combined with the melted cast
steel or the melted bar or wrought iron, by first melting the said metallic
manganese in a separate pot or crucible, and pouring it when fluid into
the melted cast steel or the melted bar or wrought iron, as the case may be;
or the metallic manganese may be alloyed, mixed, combined, and incorporated
with the melted or nearly melted cast steel, or with the melted or nearly
melted bar or wrought iron, in any other convenient manner.
The metallic manganese may also be added to cast steel materials or to bar
or wrought iron when both the former and the two latter materials are in the
cold state, and the mixture may then be melted into cast steel in the ordinary
manner; but I prefer in all cases to add the metallic manganese to the cast
steel materials, or to the bar or wrought iron, when they are in a melted fluid
state or nearly so, as by this method of combination I avoid, as much as
possible, the risk of oxydizing the manganese before it can combine and
become alloyed with the cast steel or bar or wrought iron, as the case may be.
Having thus particularly described the nature of my said Invention, and the
manner in which the same is to be performed, I hereby declare that I do not
claim the use of carburet of manganese, or carbonaceous, matter and man-
ganesc, in the manufacture of steel; but what I do claim is the addition
of metallic manganese to cast steel, however prepared, excepting only that
which is prepared from decarbonized or partially decarbonized purified cast
iron, as already set forth in Letters Patent granted to me, and bearing
date Twenty-second September, One thousand eight hundred and fifty-six.
And likewise I claim the addition of metallic manganese to bar or wrought
iron, in any convenient manner, so as to become mixed and combined in the
process of manufacture, in order, by the union of these substances, to obtain or
produce an improved quality of cast steel.
In witness whereof, I, the said Robert Mushet, have hereunto set
my hand and seal, this Eleventh day of December, in the year of
our Lord One thousand eight hundred and fifty-seven.
Witness, EDW M. MUSHET.
Witness, B. MUSHET.
ROBT MUSHET. (L.S.)