AN IMPROVEMENT IN THE ART OF MANUFACTURING IRON AND STEEL
Year: 1836

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ISAAC HAWKINS, of Chase Cottage, Pancras Vale, Hampstead Road, in the
County of Middlesex, Engineer, send greeting.
WHEREAS His present most Excellent Majesty King William the Fourth,
by His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Fourth day of July, in the seventh year of His reign, did,
for Himself, His heirs and successors, give and grant unto mic, the said John
Isaac Hawkins, His especial licence, full power, sole privilege and authority,
that I, the said John Isaac Hawkins, my exors, adiňors, and assigns, or such
others as I, the said John Isaac Hawkins, my exors, adñiors, or assigns,
should at any time agree with, and no others, from time to time and at
all times during the term of years therein expressed, should and lawfully
might make, use, exercise, and vend, within England, Wales, and the Town
of Berwick-upon-Tweed, and also in all His said Majesty's Colonies and
Plantations abroad, the Invention of "AN IMPROVEMENT IN THE ART OF
MANUFACTURING IRON AND STEEL," communicated to me by William P *
Boyden, of New York; in which said Letters Patent is contained a proviso,
that I, the said John. Isaac Hawkins, shall cause a particular description of
the nature of the said Invention, and in what manner the same is to be
performed, to be inrolled in His said Majesty's High Court of Chancery

page_text: within six calendar months next and immediately after the date of the said
in part recited Letters Patent, as in and by the same, reference being there-
unto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Isaac Hawkins, do hereby declare that the said Invention, as communi-
cated to me by the said William P Boyden, and the manner in which
the same is to be carried into effect, are fully set forth and explained in the
following Specification or description thereof (that is to say):-
The improvement consists,-
Firstly, in taking the ore of iron in the roasted state after the volatile parts
have been expelled by heat in the usual way, in which state it is technically
called "burnt mine," and subjecting it to the chemical process known by the name
of cementation, according to and in imitation of certain testing samples, to be
obtained as herein-after particularly described, in which process of cementation
the roasted ore is placed in contact with and surrounded by charcoal or other
substance containing a sufficient quantity of carbon in a closed vessel or
chamber, so as to exclude the atmosphere, while as high a degree of heat is
applied as the material will bear without being melted, by which cementation
a new product is obtained, which may, by simple and speedy common and well-
known processes, be converted into cast iron, into cast steel, or into malleable
steel or malleable iron; and,
Secondly, in forming a series of testing samples, according to which the
cementation may be conducted in order to the production of iron or steel of
the texture or quality of any one of the samples chosen.
Before describing the manner of carrying the said improvement into effect,
I will remark, that the results of the cementation will be affected by at least
seventeen distinct circumstances, all of which ought to be carefully attended
to, namely:-First, the natural quality of the ore. Second, the perfection or
imperfection of the roasting. Third, the sizes into which the lumps of ore
are broken for cementation. Fourth, the porousness or compactness of tlie
orc. Fifth, the quantity cemented in one vessel. Sixth, the internal dimen-
sions of the cementing vessels, and the thickness of their bottoms and sides.
Seventh, the setting of the furnaces for beneficially applying the heat to the
cementing vessels. Eighth, the substance from which the charcoal is burnt, as
bone, or other animal matters, hard wood, soft wood, or other substances.
Ninth, the perfection or imperfection of the burning of the charcoal. Tenth,
the freshness or staleness, dampness or dryness, of the charcoal. Eleventh, the
degree of the pulverization of the charcoal. Twelfth, the quantity of charcoal

page_text: And I would
employed. Thirteenth, the careful mixture of the lumps of ore with the
charcoal in the cementing vessel. Fourteenth, the time of getting up the fire.
Fifteenth, the time of continuing the full heat. Sixteenth, the degree of heat
applied. Seventeenth, the time of lowering the heat after the fire is extin-
guished. From a careful consideration of all these points, it will be obvious
that it is impracticable to give any fixed proportions of the ore, of the charcoal,
and of the duration of the heat, that shall produce the same results from all the
varieties of the ores, and under, all conditions of working. I am, therefore,
compelled, by the nature of the Invention, to describe certain experimental
tests, by which persons skilled in the manufacture of iron and steel can
ascertain the required proportions and treatment for any given quality of
roasted ore, in order to their producing the requisite qualities of cemented ores,
from which they may manufacture cast iron, cast or malleable steel, or malle-
able iron at pleasure, according to the samples determined on.
further remark, that in the process of cementation I make use of two methods.
In my first method I take coursely pulverized charcoal in sufficient quantity
to envelope as much as practicable every lump of roasted ore, which should
be broken into pieces of not exceeding three or four pounds weight, and I
continue the heat a greater or a lesser time, in order that the ore may obtain
its due proportion of carbon, according as I wish to have a product suitable for
being manufactured into cast iron, into cast or malleable steel, or into
malleable iron. In my second method I take an ascertained proportion
of finely pulverized charcoal and of roasted ore, in lumps not exceeding
two or three ounces in weight, and pack them carefully together in the
cementing vessel, and continue the heat until the whole of the charcoal
has operated and exhausted its powers in producing the required degree of
cementation, after which point the further continuation of the heat will bo
comparatively of little consequence. In working on a small scale, and
employing very careful assistants, the second method might yield a superior
product to the first method; but on a large scale, and where only common
laborers are to be obtained, I prefer the first method, because the superin-
tendants can more easily control the time of firing and the degree of heat
than they could the careful weighing and packing required in the second
method.
In proceeding, then, to obtain a series of testing samples as guides in
carrying the said improvement into effect upon any given quality of one
according to the first method, I take about four hundred pounds weight of
"burnt mine" of an average quality of that intended to be worked, and I
break it into lumps generally of three or four pounds weight, intermixed

page_text: with such smaller pieces as fly off in the endeavour to produce the larger
sizes, and I divide the whole quantity into twenty portions, of about twenty
pounds each, and put each portion into a strong cast-iron pot or a crucible
surrounding the lumps with coarsely pounded charcoal, without regard to pro-
portion, but of such an average quality as can be regularly supplied to the
works, and I cover the upper layer of ore in cach pot with at least half an inch
depth of charcoal, and over that I put a layer of an inch or two of sand; and to
prevent the sand being disturbed in the fire I place a tile or a metal lid
over the sand. Thus prepared I put the pots in succession into an air furnace,
in which the draught can be well regulated by an ashpit door and a flue re-
gister, and I raise the heat gradually until in about twelve hours' time it has
attained a high degree of redness bordering on whiteness, but avoiding such a
degree of whiteness as would melt cast iron. I then continue the high degree
of heat to my first pot as equally as possible for eighty hours longer, and
afterwards let it remain twelve hours to cool. I take this long time for
raising the heat and for cooling the furnace because such would necessarily be
the case in large furnaces, and because this process ought to afford a fair
sample of all the conditions of the large working; in fact, instead of twelve
hours to heat and twelve to cool it ought to be exactly the same time that the
large furnace would take to be heated and cooled, and I proceed in the same
manner with my remaining nineteen pots, except that the time of equable
licat, exclusive of the time of heating up and cooling down, I continue in my
second pot for seventy-six hours, in my third for seventy-two hours, and so on,
decreasing four hours on each pot for the times of equable heat until the
twentieth pot, which will be kept only four hours in equable heat. After the
product of the first pot is cold I separate it from the sand and charcoal, and
put the product in a cast-steel maker's crucible into his furnace, and give a
melting heat to it; the product from almost all sorts of iron ore will then pour
out into an ingot, and afford a sample of cast iron. I procced in the same
manner with the product of the second pot, and with the succeeding pots,
until the metal will not flow, but will remain while hot in a pasty state, and
can be worked into a lump by stirring with an iron rod, so as to separate the
scoria in the manner of puddling; it may then be wrought under the hammer
or passed through grooved rollers, and thus be formed into a malleable bar,
which from most ores will be a bar of mild steel. The product from the next
pot in the succession will from most ores form a bar of milder steel, and the
product of the next pot will either produce a bar of still milder steel, or a bar
of malleable iron, and the products of the remaining pots will produce bars of
malleable iron, decreasing in quality until that from the lowest time of heating

page_text: will from most ores be too crude for use. The last pot in the succession
fron which the metal will flow will produce cast steel, as will also two or
more pots preceding that, but the cast steel will be of different qualities, and
all the pots subjected to longer times of heating than the longest time of those
which produced cast steel will produce cast iron of various gradations of
quality.
In making samples as guides for the judgment for carrying the Invention into
effect according to the second method, I proceed as described for the samples
according to the first method, except that I take finely pulverized charcoal
and lumps of burnt mine, not exceeding three or four ounces in weight, and
weigh off charcoal equal to twenty-five per cent. of the weight of the ore for
the first pot, of twenty-four per cent. for the second pot, and so descending one.
per cent. for each pot until the lowest will have but six per cent. of charcoal,
and I pack the ore and the charcoal together into the pot or crucible so that
they shall be as well mixed as possible. I then subject all the pots to
twenty-four hours of equable heat, exclusive of the time of heating up and
cooling down, and treat the respective products in the cast steel maker's
crucible in the same manner as herein-before described. And I make a
second series of samples of the same proportions, to wit, from twenty-five down
to six per cent. of finely pulverized charcoal, and subject all the pots to
forty-eight hours of equable heat, and for some ores it may be useful to
make a third series of samples the same as the second, except that the equable
heat may be continued for seventy-two hours more or less. It may, in
the case of some extraordinary ores, be needful to extend the series of
testing samples from the greatest time of heating, or the greatest proportion
of charcoal, to still greater times or proportions, or to reduce the least degrees
in the series to still less degrees, and also to vary the sizes of the lumps of
roasted ore to be cemented, and it may also be useful to afford tests for still
finer shades of difference, by preparing samples intermediate between any two
of the regular series; and when I wish to obtain approximative indications
with little time and labor, I commence with a series of five pots, with quad-
ruple the differences of the series of twenty pots, and afterwards make inter-
mediate samples, as the peculiarities of the ores and the demands of the market
may require.
In carrying the improvement into effect on the large scale, I use the
ordinary steel-converting furnaces, and proceed as nearly as possible in
charging them and in firing them as I did with the testing samples which I
desire to imitate.
And I declare that I lay no claim to any part of the process of roasting

page_text: the ore, or of casting the iron or the steel, or of the mode of producing the
malleable steel or malleable iron from the cemented product; nor do I
claim the cementation of roasted ore as far as chemical experiment is
concerned, because I am aware that such chemical experiments have hereto-
fore been made; but I do claim the application of the process of cementing
roasted ore in a manufacturing way, regulated by a systematic series of testing
samples for the obtaining of a new product capable of being, by the simple
and well known process of casting, converted into cast iron or cast steel, or by
the usual processes of puddling, balling, or looping, and afterwards passing
under the hammer, or through the grooved rollers in the manner usually
employed for the formation of malleable steel or malleable iron, as herein-
before described.
In witness whereof, I, the said John Isaac Hawkins, have hereunto set
my hand and seal, this Fourth day of January, in the year of our
Lord One thousand eight hundred and thirty-seven.
JOHN ISAAC (L.S.) HAWKINS.
AND BE IT REMEMBERED, that on the Fourth day of January, in
the year of our Lord 1837, the aforesaid John Isaac Hawkins came before
our said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stamped according
to the tenor of the Statute made for that purpose.