IMPROVEMENTS IN THE MANUFACTURE OF STEEL
Year: 1854

page_text: LETTERS PATENT to Jean François Jules Alexandre Boullet, of La
Chapelle, St. Denis, near Paris, in the Empire of France, and of
16, Castle Street, Holborn (City), London, for the Invention of "IM-
Sealed the 12th December 1854, and dated the 11th October 1854.
COMPLETE SPECIFICATION filed by the said Jean François Jules Alexandre
Boullet at the Office of the Commissioners of Patents, with his Petition
and Declaration, on the 11th October 1854, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
I, JEAN FRANÇOIS JULES ALEXANDRE BOULLET, of La Chapelle, St. Denis,
near Paris, in the Empire of France, and of 16, Castle Street, Holborn (City),
London, do hereby declare the nature of my Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF STEEL" to be as follows:-
My improvements apply to cementing or converting into steel in a shorter
time, and more satisfactorily than is at present done, any pieces of wrought
iron, (viz., sheets, bars, parts of machinery, &c.,) such wrought iron having
been obtained either by charcoal, coke, or coal, and treated in any of the usual
ways, such as by hammering, rolling, &c. I attain this object by using a
furnace of a novel construction, which I shall describe hereafter, and also a

page_text: chemical compound, which exerts a powerful cementing action even upon
inferior descriptions of iron.
In order that the said improvements may at once be fully and properly
understood, I shall now proceed to describe the several Figures on the Sheet
of Drawings hereunto annexed.
Fig. 1 of the Sheet of Drawings annexed represents the improved furnace
in vertical longitudinal section, through the line X, X, of Fig. 2, which
represents the furnace in plan, the top plate 9 being removed. Fig. 3 shews
a vertical cross section through the line Y, Y, Fig. 1. Fig. 4 is a complete
external side elevation of the furnace.
A is an outer brick casing, which surrounds the cementing case or box B,
in such manner as to leave an empty space C all around it. At one of the
extremities of the outer casing is the fire-place and grate D, and at the other
the chimney E. The box B rests on two rows or courses of bricks F, F, which
divide the sole of the furnace into three flues G, G', G. H, H, H, are two
rows or ledges of bricks or stone, dividing the vertical side spaces C into two
lateral channels I, I', on each side of the furnace. Owing to the partitions K,
the lower side channels communicate only with the flues G, G, and, owing to
both the partitions K and L, the middle flue G¹ only feeds the two upper chan-
nels 1', 1'; besides this, the gases, &. passing through the middle flue G', are
divided into two branches by a partition K', at the back end of the cementing
box. All these flues and channels unite into one exit flue M, M', in front and
on the top of the cementing box B; thus, the flames and burning gases, after
having passed over the fire bridge at the entrance of the furnace sole, are
divided into three branches G, G, G; they then pass through the channels
I, I, I, I', respectively into the front space M, and escape through the top flue
M' into the chimney E. N, N, are holes on the three vertical sides of the outer
casing, for examining the temperature of the cementing box. The apertures
O, O, which communicate with the ash box P, are intended for accelerating the
draught. These holes N, O, are stopped with pieces of bricks or otherwise.
Qis a moveable plate or lid of cast iron, by which the furnace is closed above.
R, R, are moveable damper bricks, passing through the brickwork of the
chimney. By means of these bricks I regulate and direct the draught of the
furnace, by diminishing or increasing the aperture between the flue M and
the chimney E, and by so arranging the relative position of the bricks, as to
bring the said aperture farther on one side or the other of the furnace. Similar
damper bricks may also be left loose at various points of the lateral flues, so as
to enable the operator to check the draught at the places where the cementing
box B should get too hot. The box B is made of cast iron, or fire clay slabs

page_text: or bricks, and there are cast-iron pipes adapted to its sides, projecting outside
the brickwork, so that trial pieces may be inserted into the cementing box,
and be withdrawn from time to time for the purpose of ascertaining the
progress of the cementation or steeling process.
66
The compound cementing substance which I have devised for the more
effectual and speedier conversion of any kind of iron into steel is a mixture of
glucose" or other saccharine matter, of horn sawdust or horn shavings,
of graves, or residue of animal fat, of dried blood, and charcoal of any wood,
These matters have to be pulverized or comminuted into as small portions
as possible, if they are not already in a powdery state, and the whole has to be
thoroughly mixed, so as to form one homogeneous mass. As to the proportions
of the different articles,. they have necessarily to be varied, according to the
kind and size of the iron to; be cemented. ⚫
When it is desired to charge the furnace, the way I find most convenient is
by forming on the bottom of the furnace a layer of cement, of one inch and a
half in thickness, & the articles desired to be cemented, having been coated
with glue or oil, they are laid one by the side of the other, at a distance of
from three-eighths to three-quarters of an inch, according to the thickness of the
pieces. The space between the pieces is then filled up with cement, after which
they are covered up with a layer of cementing matter, of three-quarters of an
inch thickness, and so on till the successive layers reach to within about four
inches from the top of the box B. The last layer thus arrived at being carefully
levelled, a border of fine riddled cinders or ashes, of about three-quarters of
an inch height and two inches wide, is arranged all round the box against the
sides. On this border I lay one or more wrought-iron plates (according to
the size of the furnace) in such manner as to cover or fill up its whole
surface. On this plate I lay another border of ashes, like the under one, and
the hollow is filled up with a thickness of sand of about two inches and one
half, and the edge of the outer case A being about four inches higher than
the edge of the cementing box. The furnace is closed with a cast-iron plate or
lid Q, or else with brickwork carefully luted, thus leaving the top flue M¹.
The furnace having been thus charged, the fire may be lighted, keeping it
at a moderate degree at first, and then gradually increasing its intensity until
the box reaches a pale cherry-red heat. This temperature is kept up regularly
during 24 hours for small articles of one quarter of an inch thickness; during
86 hours for those of double that thickness; 48 hours for articles of seven-
eighths of an inch thickness; 72 hours for those one inch and one quarter in
thickness, and so on; the time required for greater thicknesses being four days
or more.
Pieces of irou similar to those to be steeled, having been inserted

page_text: into the cementing box B, (being luted into the testing holes or pipes above
inentioned,) may be taken out from time to time, and thus the state of
cementation can be ascertained. If the steeling has attained the desired
degree, the fire is extinguished, and the cementing box is left to cool, until
the articles may be taken out by hand.
Having thus described the nature of my Invention, and the manner in
which the same is or may be carried into effect, I wish it to be understood
that I do not strictly confine myself to the practical details set forth; but what
I claim as novel, and secured to me by the herein-before recited Letters
Patent, is,
First, the construction of a cementing furnace substantially as described
above, viz., there being circulating flues G, I, M, on all sides of the cementing
box B, with or without dampers for regulating the heat in different parts of
the furnace.
Second, the steeling cement above described, and consisting of glucose or
other saccharine matter, horn shavings or horn sawdust, graves, or residue
of animal fat, dried blood, and charcoal.
In witness whereof, I, the said Jean François Jules Alexandre Boullet,
have hereunto set my hand and seal, this Seventh day of October,
in the year of our Lord 1854.
J Fers Jums ARE BOULLET. (L.S.)