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

page_text: LETTERS PATENT to Robert Mushet, of Coleford, in the County of
Gloucester, Metallurgist, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF STEEL IRON AND CAST STEEL."
Sealed the 2nd August 1859, and dated the 15th February 1859.
PROVISIONAL SPECIFICATION left by the said Robert Mushet at the
Office of the Commissioners of Patents, with his Petition, on the
15th February 1859.
I; ROBERT MUSHET, of Coleford, in the County of Gloucester, Metal-
lurgist, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN THE MANUFACTURE OF STEEL IRON AND CAST STEEL," to be as follows:-
When cast iron has been wholly decarbonized or partially decarbonized by
the action of air passed or forced through it whilst it is in a molten or fluid
state, it has been found that although the cast iron which has been thus
wholly decarbonized or partially decarbonized may be cast into ingots' or
pieces by pouring the metal into suitable moulds, the masses of steel iron
or steel thus obtained prove, in some instances, incapable of extension by
hammering or rolling at any temperature; in other instances they may be
extended into bars by hammering or rolling, but the bars thus produced
frequently have 'cracks along their edges and flaws along their sides, so as to
unfit them for, manufacturing purposes, and even when the bars prove to be
tolerably sound the quality of the iron or steel is frequently found to be more
or less defective. For the purpose of remedying these defects, or some of

page_text: them, in the steel iron or steel thus obtained by wholly decarbonizing or
partially decarbonizing cast iron whilst in a molten state, and in order to
convert it into steel iron or steel suited for commercial and manufacturing
purposes, I add to the wholly decarbonized or partially decarbonized cast iron
whilst in the melted state a quantity of welding cast steel, also in the melted
state, so that these two substances may become combined, and I then pour the
mixture into suitable moulds, in order to obtain ingots or castings of the
required form or size. The welding cast steel which I employ is cast steel
containing metallic manganese, and which may be readily produced by melting
steel together with a metallic compound of iron, carbon, and manganese, such
as the "spiegel eisen" of Rhenish Prussia. To those kinds of steel which
already contain metallic manganese, it is unnecessary to add the said metallic
compound of iron, carbon, and manganese. The relative proportions of the
wholly decarbonized or nearly decarbonized cast iron and the melted welding
cast steel may be varied at the will of the manufacturer; but I have found in
practice that by varying the proportion of the melted welding cast steel
between five parts by weight and thirty parts by weight of the said melted
welding cast steel to one hundred parts by weight of the wholly decarbonized
or nearly decarbonized melted cast iron, steel iron or steel of the qualities
required in commerce may be produced; and I here observe that when the
cast iron has been wholly decarbonized the addition of a small proportion
of the melted welding cast steel to it will yield steel iron, semi-steel, or very
soft steel, and the addition of a larger proportion of the melted welding cast
steel to the wholly decarbonized cast iron will yield a somewhat harder but
still a soft or mild quality of cast steel. And if the melted cast iron has been
only partially decarbonized, and is in the state of steel, the addition to it of
the melted welding cast steel will form a steel of a quality softer or harder
in proportion as the cast iron has been previously more or less decarbonized.
The combination of the welding cast steel and of the decarbonized or
nearly decarbonized cast iron may be effected by pouring the melted sub-
stances into any suitable heated ladle, furnace, or vessel, and accelerating
their union, if necessary by stirring the mixture with an iron or steel rod:
The cast iron may be decarbonized or partially decarbonized in any suitable
furnace or vessel, by forcing or passing air through it whilst it is in a molten
state, in the manner patented by Henry Bessemer, or in any other convenient
manner. The welding cast steel may be melted in the usual manner in pots
or crucibles placed in an ordinary furnace for melting cast steel. The kind of
welding cast steel which I prefer to use is that which has been combined with
a compound of iron, carbon, and manganese, but welding steel which has

page_text: been prepared in any other convenient manner may be used to mix with the
decarbonized or nearly decarbonized cast iron. The essence of my Invention
consists in combining cast iron, decarbonized or partially decarbonized by
passing air through it whilst in the fluid state, with welding cast steel, the
union of these substances being effected by mixing them together whilst both
of them are in a melted fluid state, in order to obtain thereby malleable steel
iron or steel suited for commercial purposes.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert Mushet in the Great Seal Patent Office on the
4th August 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 Fifteenth 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 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 "Iж-
PROVEMENTS IN THE MANUFACTURE OF STEEL IRON AND 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 following
statement thereof, that is to say:-

page_text: When cast iron has been wholly decarbonized or partially decarbonized by
the action of air passed or forced through it whilst it is in a molten or fluid.
state, it has been found that although the cast iron which has been thus wholly
decarbonized or partially decarbonized may be cast into ingots or pieces by
pouring the metal into suitable moulds, the masses of steel iron or steel thus
obtained prove, in some instances, incapable of extension by hammering or
rolling at any temperature; in other instances masses of the said steel iron-
or steel may be extended into bars by hammering or rolling, but the bars
thus produced frequently have cracks along their edges and flaws along their
sides, so as to unfit them for manufacturing purposes, and even when the bars.
prove to be tolerably sound, the quality of the iron or steel is frequently found
to be more or less defective. For the purpose of remedying these defects, or
some of them, in the steel iron or steel thus obtained by wholly decarbonizing
or partially decarbonizing cast iron whilst in a. molten state, and in order to
convert it into steel iron or steel suited for commercial and manufacturing.
purposes, I add to the wholly decarbonized or partially decarbonized cast iron.
whilst in the melted state a quantity of welding cast steel, also in the melted
state, so that these two substances may become combined, and I then pour the
mixture into suitable moulds, in order to obtain ingots or castings of the
required form or size. The relative proportions of the wholly decarbonized.or
nearly decarbonized cast iron and the melted welding cast steel may be varied
at the will of the manufacturer; but I have found in practice that by varying
the proportion of the melted welding cast steel between five parts by weight
and thirty parts by weight of the said melted welding cast steel to every one
hundred parts by weight of the wholly decarbonized or nearly decarbonized
melted cast iron, the various qualities of steel iron or steel required in com-
merce may be produced. When the cast iron has been wholly decarbonized
the addition of a small proportion of the melted welding cast steel to it will
yield steel iron, semi-steel, or very soft steel, and the addition of a larger
proportion of the melted welding cast steel to the wholly decarbonized cast
iron will yield a somewhat harder but still a soft or mild quality of cast steel.
And if the melted cast iron has been only partially decarbonized, and is in the
state of steel, the addition to it of the melted welding cast steel will form a
steel of a quality softer or harder in proportion as the cast iron has been
previously more or less decarbonized. The combination of the welding' cast
'steel and of the decarbonized or nearly decarbonized cast iron may be effected
by pouring the melted substances into any suitable heated ladle, furnace, or
vessel, and accelerating their union if necessary by stirring the mixture with
an iron or steel rod. The cast iron may be decarbonized or partially decar-

page_text: bonized in any suitable furnace or vessel, by forcing or passing air through it:
whilst it is in a molten state, or in any other convenient manner. The welding,
cast steel may be melted in the usual manner in pots or crucibles, placed in.
an ordinary furnace for melting cast steel. The kind of welding.cast steel.
which I prefer to use is that which has been combined with a compound of.
iron, carbon, and manganese, but welding cast steel prepared in any other
convenient manner may be used to mix with the decarbonized or nearly.
decarbonized cast iron. In order to obtain welding cast steel best suited for
my process, I melt in ordinary steel melting pots such materials as will
produce a soft, or, as it is termed, a mild quality of cast steel. Into every
twenty pounds of such soft steel, when melted, I pour from two to five pounds.
of a melted triple compound of iron, carbon, and manganese, and to every one.
hundred pounds of cast iron, decarbonized or partially decarbonized by passing.
air through it, I add from five pounds to thirty pounds of the mixture of mild
steel and the triple compound of iron, carbon, and manganese. I then stir the
mixture with a rod of iron or steel, and then pour the said mixture into ingot
or other moulds. The triple compound of iron, carbon, and manganese which
I prefer to use, is the, white crystalline cast metal, known in Prussia as
"spiegel eisen," and which is smelted in the blast furnace with charcoal fuel
from spathose iron ores, containing besides iron a large per-centage of man-
ganese. "Spiegel eisen" contains from two to eight per centum of metallic
manganese alloyed with iron. The cast iron is decarbonized or partially
decarbonized for my process by passing air through.the said cast iron when in
the melted state. When the cast iron has been decarbonized so far as to be
in the state of steel, or when it has been decarbonized so as to have passed
into the state of malleable iron, I pour the said partially. or wholly decar-
bonized cast iron into a ladle, coated with loam or black lead, and previously
strongly heated. The requisite quantity of welding cast steel, prepared as
herein-before described, is then quickly poured from the melting pots or
crucibles in which it has been previously melted, into the ladle containing the
partially or wholly decarbonized cast iron. The mixture in the ladle is stirred
with a rod of iron or steel, and is then quickly teemed or poured into ingot or
other suitable moulds. I wish it to be observed that in preparing the wolding
cast steel for mixture with the partially or wholly decarbonized cast iron, the
greater the relative proportion of the triple compound of iron, carbon, and
manganese added to the soft or mild cast steel, the harder will be the welding
cast steel formed by the combination of these materials, and the harder will
be the cast steel obtained by mixing the welding cast steel thus prepared with
partially or wholly decarbonized cast iron. Therefore by increasing or

page_text: diminishing the relative proportions of the triple compound of iron; carbon,
and manganese, added to soft or mild cast steel, welding cast steel will be
obtained, which when added to partially or wholly decarbonized cast iron will
produce with the said cast iron, steel or steel iron of a greater or lesser degree
of hardness.
Having thus described the nature of my Invention, and the manner in which
it may be carried into effect, I wish it to be clearly understood that the essence
of my Invention consists in combining cast iron, decarbonized, or partially
decarbonized by passing air through it whilst in the fluid state, with welding
cast steel, obtained by melting suitable materials in melting pots or crucibles
heated in ordinary steel melting furnaces, the union of the said welding cast
steel and decarbonized or partially decarbonized cast iron being effected by
mixing them together whilst both of them are in a melted fluid state, in order
to obtain thereby malleable steel iron or steel suited for commercial purposes.
In witness whereof, I, the said Robert Musliet, have hereunto set my
hand and seal; this Nineteenth day of July, in the year of our Lord
One thousand eight hundred and fifty-nine.
Witnesses,
EDWP. M. MUSHET,
Coleford, Gloucestershire.
BROOKLYN MUSHIET,
Coleford, Gloucestershire.
ROB. MUSHET. (L.S.)