A MODE OF MANUFACTURING STEEL
Year: 1860

page_text: LETTERS PATENT to Asahel Knowlton Eaton, of the City of New York, in
the State of New York, one of the United States of America, for the
Invention of "A MODE OF MANUFACTURING STEEL."
PROVISIONAL SPECIFICATION left by the said Asahel Knowlton Eaton
at the Office of the Commissioners of Patents, with his Petition, on
the 25th April 1860.
I, ASAHEL KNOWLTON EATON, of the City of New York, in the State of New
York, one of the United States of America, do hereby declare the nature
of the said Invention for "A MODE OF MANUFACTURING STEEL," to be as
follows:-
It consists in a mode of treating cast iron in the form of bars, plates, or
other shape involving uniformity of thickness so as to convert it into steel,
and to purify it at the same time by removing a portion of the carbon and
separating the sulphur, silicon, and other impurities contained in the iron
by subjecting it in combination with carbonate of soda or other substance
herein-after named to heat. The iron is packed in a suitable vessel with
carbonate of soda sufficient when in a melted state to cover it, and arranged
so that the soda can have access to all parts. The receptacle is then sub-
jected to a bright red heat until the iron is found by testing from time to time,
one of the bars withdrawn for the purpose, that the conversion is complete.

page_text: The decarbonization is arrested when the proportion of carbon in the
iron is found to be reduced to that required in good steel. Thus converted,
the material may be worked in the ordinary manner for use. The carbonate
of potash may be substituted for that of soda in the process.
A combination of the carbonates of soda & potash in equivalent propor-
tions forms a mixture more fusible than soda alone, and it may therefore be
desirable sometimes to use it. The oxides of iron & zine may also be
profitably used in some cases in combination with soda.
The hydrates of potash and soda may be used instead of the carbonates,
but are not so convenient or economical.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Asahel Knowlton Eaton in the Great Seal Patent Office
on the 25th October 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ASAHEL
KNOWLTON EATON, of the City of New York, in the State of New York, one
of the United States of America, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of April, in the year of our Lord
One thousand eight hundred and sixty, in the
year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Asahel Knowlton Eaton, Her special licence that I, the said Asahel Knowlton
Eaton, my executors, administrators, and assigns, or such others as 1, the
said Asabel Knowlton Eaton, 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
"A MODE OF MANUFACTURING STEEL," upon the condition (amongst others) that
1, the said Asabel Knowlton Eaton, 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 Asahel Knowlton Eaton, do hereby
declare the nature of my said Invention, and in what manner the sanie is

page_text: to be performed, to be particularly described and ascertained in and by the
following statement :-
It consists in a new process of manufacturing steel from cast iron. Cast
iron in the form of thin bars or plates is packed in an iron box or other
suitable receptacle, with sufficient carbonate of soda completely to cover the
bars when the salt is in a melted state. The box with its contents is sub-
jected to a bright red heat for several hours, the time varying with the thick-
ness of the bars.
The soda salt acts both as a purifier of the iron and as a decarbonizing
agent. The carbon of the cast iron is gradually eliminated through its affinity
for the oxygen of the soda, and passes off as carbonic oxide. Sodium is set
free and volatilized, and may be collected beneath the surface of liquids that
contain no oxygen in their composition (melted paraffin is a suitable liquid for
this purpose.) It is more convenient, however, to allow the sodium to become
re-oxidized by admitting just air enough to effect the purpose through a small
opening in the top of the containing vessel. Soda is thus reproduced for
future use. The process of decarbonization is arrested at such a stage of the
operation that there will be left in the iron just the amount of carbon requi-
site for good steel.
The impurities of the cast iron, silicon, sulphur, and phosphorus are also
eliminated, and consequently we find the silicate of soda, and the sulphuret and
phosphuret of sodium in the residuum after the completion of the process.
The condition of the iron and the progress of the operation may be deter-
mined at any time by withdrawing a bar and testing it.
The carbonate of potash may be substituted for that of soda in this process.
If we make use of a combination of the carbonates of potash and soda in
the proportion of their equivalents, the mixture will retain its fluidity at a
lower temperature than soda alone, and therefore would be sometimes prefer-
able. The oxides of iron and zinc may be used with good effect in combina-
tion with the carbonates described.
The hydrates of potash and soda may be used instead of the carbonates, but
neither so conveniently nor so economically.
After the carbonates have become very impure by continued use, they may
be purified by pulverizing, mixing with sawdust, and exposing to a red
beat. The resulting material is dissolved in water and re-crystalized. The
bars converted into steel by this process may be worked directly under the
hammer in rolls, or it may be melted, cast into ingots, and hammered.
This process presents the following essential advantages:-It insures the
manufacture of a uniform article; it removes silicon, sulphur, and phosphorous,

page_text: impurities that are only partially removed in the preparation of the best bar
iron for the ordinary steel process; it diminishes materially the cost of manu-
facture of both the common and the superior kinds of steel.
Having thus fully described the Invention and the manner in which it is
to be operated, what I claim and desire to secure under the herein-before in
part recited Letters Patent is, the conversion of cast iron in its solid form into
steel, and the simultaneous purification of the same by treatment with the
hydrates or carbonates of soda and potash, either alone or combined substan-
tially as herein described.
In witness whereof, I, the said Asabel Knowlton Eaton, have hereunto
set my hand and seal, on this Ninth day of August, anno Domini One
thousand eight hundred and sixty.
In presence of,
JOHN T. PITMAN.
ASAHEL KNOWLTON EATON. (L..s.)