IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1869

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL." -A
communication from abroad by Howard Spencer and Lafayette
Kauffman Taylor, both of Philadelphia, in the United States of
America.
Sealed the 12th April 1870, and dated the 30th December 1869.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents, with his Petition, on the
30th December 1869.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL,
a communication to me from abroad by Howard Spencer and Lafayette
Kauffmann Taylor, both of Philadelphia, in the United States of
America, to be as follows :-
This Invention consists in converting iron ore directly into steel or
into refined cast iron at one operation and in one chamber of a furnace
substantially in the manner herein-after described.

page_text: In carrying out this Invention a cupola or other suitable variety of a
blast furnace may be employed. The ore used may be of that character
known as magnetic or black oxide of iron, red hematite, and titaniferous or
other iron ores, the several qualities of ore being employed either separately
or together. The fuel employed may be charcoal, and the furnace may
contain a single reducing chamber, which may be less deep in front than
at the rear; this chamber may communicate through a fluo with a
suitable chimney. A hot blast may be used and introduced through,
say, four tuyeres, namely, two on each side, the orifices of the tuyeres
being situated, say, about ten inches above the hearth of the reducing
chamber, and inclined downwards towards the latter. The ore may be
first stamped or crushed, or otherwise granulated. The fire having been
properly kindled the surface of the ignited fuel should be sprinkled with
a layer of granulated ore; then a layer of charcoal or other fuel is added,
then more ore and fuel, the intervals of feeding with ore and fuel being
determined by the condition of the fire and metal. When the metal
appears to be too thick powdered quartz in small quantities may be
occasionally added as a flux. Towards the close of the operation, when
the mass of molten metal extends nearly to the tuyeres, the feeding with
fuel (but not with ore) is discontinued for a short time, and the force of
the blast is increased for from five to ten minutes, so as to maintain the
metal in a state of ebullition before tapping. After tapping the operation
is promptly resumed, the only interruption in the continuity of the
process being the few minutes consumed in tapping, and in causing the
blast to play with increased force on the molten metal for a short time
prior to tapping.
It may be remarked here that the waste heat of the furnace may be
utilized by arranging in the flue a system of pipes through which the air
may be forced to the tuyeres, and that in feeding the furnace the
granulated ore and the charcoal or other fuel may be deposited in an
inclined position, the ore and fuel being fed through a convenient
opening in the front or other part of the furnace, this opening being
furnished, if desired, with a hinged door.
As before stated a cupola or other suitable variety of a blast furnace
may be employed when it is desired to conduct the operation on a larger
scale, and it will be evident that the mode of feeding must be varied to
some extent according to the character of the furnace and to that of the
ore employed. Mineral fuel may also in some cases be used in place of
charcoal.

page_text: The character of the fluxes used must be regulated in accordance with
the character of the ore to be reduced; in fact, the judgment of those
well versed in the manufacture of iron and steel will be necessary to
some extent in carrying out the Invention.
In feeding the furnace it is generally advisable to introduce the ore
slowly in the first instance and faster after the heat of the furnace has
become more intense. The rapidity with which the furnace is fed will
depend upon the fluidity of the metal. Should the metal be too thick
more fuel should be added and a less proportion of ore fed to the furnace,
and the fluidity of the metal may be increased by a little granulated
silica or such other flux as the character of the ore may demand, or by
increasing the force of the blast.
A most important point in carrying out this Invention is that the
metal should be maintained in a very fluid condition, and that after
the ore has been reduced the blast should be strengthened and allowed
to act on the metal, the metal being thereby maintained in a state of
ebullition and purified and partly decarburized, after which it may be
drawn off and cast into suitable ingots.
Small quantities of manganese or chromate of iron may be added to
the ore for producing steel of different grades.
If the metal in reducing the ore be very highly carbonised less fuel
should be used, and the ore should be fed more rapidly to the furnace.
Wrought iron in small quantities may be added to the molten metal,
so as to aid in decarburizing the same and modify the quality of the
steel.
In making refined cast iron or a low grade of steel the ore may be fed
to the furnace more slowly, and the quantity of fuel should be increased.
The blast of increased force during the close of the operation should be
continued for from five to ten minutes, or for such a length of time as
may be necessary to partly decarburize and purify the metal sufficiently
to make either a high or low grade of steel.
In addition to the economical manufacture of cast steel and refined
cast iron by the above-described process it has been found that the latter
may with slight modifications in the treatment of the ore be applied to
the direct conversion of the same into a refined wrought iron.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 27th June 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of December, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license
that I, the said John Henry Johnson, my executors, administrators,
and assigns, or such others as I, the said John Henry Johnson,
my exccutors, administrators, or 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,
чse, exercise, and vend, within the United Kingdom of Great
Britain and Ireland, the Channel Islands, and Isle of Man, an Inven-
tion for "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL," a com-
munication from abroad by Howard Spencer and Lafayetta Kauffmann
Saylor, both of Philadelphia, in the United States of America, upon
the condition (amongst others) that I, the said John Henry Johnson,
my executors or administrators, by an instrument in writing under
hand and seal, 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 John Henry Johnson, 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, reference being had to the accom-
panying Drawings, and to the letters and figures marked thereon (that
is to say):-
The said Invention consists in converting iron ore directly into steel
or into refined cast iron at one operation and in one chamber of a
furnace, substantially in the manner herein-after described.

page_text: In carrying out this Invention a cupola or other suitable variety of a
blast furnace may be employed.
And in order that the said Invention may be fully understood I shall
now proceed more particularly to describe the same, and for that
purpose shall refer to the several Figures on the annexed Sheet of
Drawings, the same letters of reference indicating corresponding parts
in all the Figures.
Figure 1 of the Drawings is a vertical section of a furnace which has
been found to give good results in carrying out this process; and
Figure 2 is a transverse vertical section taken along the line 1-2,
(Figure 1).
The ore employed may be of that character known as magnetic or
black oxide of iron, red hematite, and titaniferous or other iron ores, the
several qualities of ore being employed either separately or together.
The fuel employed may be coke, charcoal, or other fuel, and the
furnace may contain a single reducing chamber A about two feet square,
two feet deep in front, and about four feet six inches deep at the rear.
This chamber communicates through a flue B with a suitable chimney D.
A hot blast may be used introduced through, say, four tuyeres b, b, namely,
two on each side, the orifices of the tuyeres being situated, say, about ten
inches above the hearth a of the reducing chamber and inclined down-
wards towards the latter, as shewn in Figure 2 of the Drawing. The
ore is first stamped or crushed or otherwise granulated or divided. The
fire having been properly kindled the surface of the ignited fuel should
be sprinkled with a layer of granulated or divided ore, then a layer of
charcoal is added, then mare ore and more charcoal or other fuel, the
intervals of feeding with ore and fuel being determined by the condition
of the fire and metal produced. When the reduced ore appears to be
too thick powdered quartz in small quantities may be occasionally added
as a flux, or other fluxes may be employed. When the charge of ore has
been reduced or nearly so, and when the mass of molten metal has
nearly reached the tuyeres the feeding with charcoal or other fuel (but
not with ore) is discontinued for a short time, and the force of the blast
is increased for from five to ten minutes so as to maintain the metal in
a state of ebullition before tapping. After tapping the reducing process
or operation is promptly resumed, the only interruption in the continuity
of the process being the few minutes consumed in tapping, and in
causing the blast to play with increased force on the molten metal for a

page_text: short time prior to tapping. The waste heat of the furnace may be
utilized by arranging in the flue B a system of pipes through which
the air is forced to the tuyeres, and that in feeding the furnace the
granulated or divided ore and the charcoal or other fuel are deposited
in an inclined position, shewn by the line x in Figure 1, the ore
and fuel being fed through an opening y in the front of the furnace,
and this opening being furnished if desired with a door hinged at
the top, as shewn in the Drawing. As before stated a cupola or other
suitable variety of a blast furnace may be employed, the dimensions
of which will be dependent on the scale on which it is desired
to conduct the operation. When it is desired to conduct the operation
on a larger scale it will be evident that the mode of feeding must be
varied to some extent according to the character of the furnace and to
that of the ore employed. Mineral fuel may also in some cases be used
in place of charcoal or coke. The character of the fluxes used is to be
regulated in accordance with the character of the ore to be reduced, as is
well understood. In feeding or charging the furnace it is generally
advisable to introduce the ore slowly in the first instance, and to increase
the quantity after the heat of the furnace has become more intense.
The rapidity with which the furnace is fed will depend upon the fluidity
of the metal, which may be tested from time to time. Should the
reduced metal be too thick or pasty more fuel should be added and a less
proportion of ore fed to the furnace, and the fluidity of the metal may
be increased by a little divided silica or such other flux or fluxes as the
character of the ore may demand, or similar results may be obtained by
increasing the force of the blast.
A most important point in carrying out this Invention is that the
metal should be maintained in a very fluid condition, and that after the
ore has been reduced the blast should be strengthened and allowed to
act on the metal so as to maintain the same in a state of ebullition and
thus purify and partly decarburize it, after which operation it may be
drawn off and cast into suitable ingots or moulds. Small quantities of
manganese or oxide of manganese or of chromate of iron may be added
to the ore for the purpose of producing steel of different qualities. If
the reduced metal be very highly carbonized less fuel should be used,
and the ore should be fed more rapidly to the furnace. Wrought iron
in small quantities may be added to the molten metal so as to aid in
decarburizing the same, and thus modify the quality of the steel

page_text: produced. In making refined cast iron or a low quality of steel the ore
should be fed to the furnace more slowly and the quantity of fuel should
be increased. The blast of increased force employed during the close of
the operation should be continued for from five to ten minutes or for
such a length of time as may be necessary to partly decarburize and
purify the metal sufficiently to make either a high or low quality of
steel. In addition to the economical manufacture of refined cast iron
and cast steel by the above-described process wrought iron may with
slight modifications in the treatment of the ore be by this process
obtained.
It may be remarked in conclusion that in the furnace referred to and
illustrated in the Drawing and by the adoption of the process before
described iron ore may be converted directly into steel at about the
rate of five hundred pounds in three hours.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider
to be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is, the process or
method of converting iron ore in one and the same furnace either into
refined cast iron, or into cast steel, or into wrought iron, substantially in
the manner herein-before described.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, this Twenty-seventh day
of June One thousand eight hundred and seventy.
TENDY JOHNSON
J. HENRY JOHNSON. (..)