TUT name on Trex iND STEET
Year: 1855

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, New
Cannon Street, in the County of Middlesex, Engineer, for the Invention
- TUT name on Trex iND STEET"
Sealed the 27th March 1855, and dated the 10th January 1855.
PROVISIONAL SPECIFICATION left by the said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the
10th January 1855.
I, HENRY BESSEMER, of Queen Street Place, New Cannon Street, in the
County of Middlesex, Engineer, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL" to be.
as follows:-
My improvements commence at that stage of the manufacture of iron known
as the refining process, and consist in running out the metal from the finery
furnace into large ingots or moulds, having numerous partitions, for the purpose
of facilitating the breaking up of the metal into uniformly small pieses or bars.
Charcoal should be used in the finery furnace, although coke may be substi-
tuted; in either case the process should be carried further than usual. The
ingots of metal so produced (by way of distinction) I call product No. 1.
When fine metal has been treated in the puddling furnace until it is reduced to
an incoherent state, somewhat like sand, it may be removed from the furnace,
and in this state constitutes product No. 2. The further working of the iron,
and its formation into very small puddle balls, which are rolled out of the

page_text: furnace and allowed to cool, I distinguish as product No. 3. When, however,
the puddle balls are made of the usual size, and the whole of the process of
making bar iron is gone through, I pass the bars, while still red hot, between
a pair of rolls, having raised triangular ribs running lengthwise, by means of
which the bar is cut into short pieces of an uniform size, and in which state
it constitutes product No. 4. To these different products may be added a fifth,
consisting of boiler-plate parings, punchings, bar ends, and scrap iron, all of
which products, distinguished as Nos. 1, 2, 3, 4, and 5; are to be converted
into steel by the following processes:-For this purpose, I prepare a furnace
very simular in its general arrangements to the retort furnaces used in the
manufacture of gas. Into this furnace are placed any convenient number of
fire clay or iron retorts, the open ends of which project several feet through
the walls of the furnace. Into these retorts are placed a series of iron plates,
connected by iron bars at the distance of about two or three feet apart, some-
what like the buckets in a chain pump. Near to one end of the retorts is
placed a winding apparatus for moving forward the plates, which are thus made
to divide the retorts into seperate chambers. Into these chambers either of
the products Nos. 1, 2, 3, 4, or 5. are to be placed, with charcoal powder
between and among them. The partition plates are made to advance, by means
of the winding apparatus, a small distance every day, the time occupied in their
transit through the retorts varying from 6 to 12 days, or thereabout, according to
the thickness of the metal, or to the extent to which the process of cementation
is desired to be carried. The cooling down of the charcoal, and the iron which
has been converted into steel by the process, takes place in the elongation of
the retort outside the furnace, which also prevents the access of air to the
materials occupying that part of the retorts which are exposed to the action of
the fire. I next proceed to convert the crude steel so produced into cast steel,
for which purpose I employ a reverbatory furnace. The part behind the fire
bridge is constructed with fire bricks, and forms a shallow basin or bath,
into which I put glass of borax, sal-ammoniac, or other fluxes, combined
with refuse glass, or other vitrious substances, so as to form a fluid matter
capable of bearing the heat of the 'furnace, and of covering the steel and
keeping it from the injurious influence of the atmosphere and vapours of the
furnace. Any of the products Nos. 1, 2, 3, 4, and 5, after the process of
cementation, are put into the basin of flux, and are there brought to a complete
state of fusion; after which the basin may be tapped, and the fluid steel may be
cast into ingots for "tilting," or it may be formed in sand or other moulds into
numerous articles.. In some cases I find it preferable to use a cupola furnace,
such as is commonly employed by iron founders, in which case charcoal should

page_text: be used as fuel with hot blast, the steel, when melted, being run out for the
purposes before mentioned. Whichever furnace is employed for the melting of
the steel, I find it advantageous to heat the steel in a retort or separate furnace,
or in another less heated part of the same furnace. I also find it useful in
this preliminary heating to use borax or other flux, as the coating of the steel
with them lessens the oxydation and decarbonization of the steel.
I have hitherto described my method of treating iron and converting it into
steel of different qualities; but I desire it to be understood that an important
part of my Invention, consists in combining the steel so made, or steel other-
wise made with cast or pig iron, for which purpose the iron may be melted
in an ordinary cupola furnace, and be then run into the bath of melted steel in
the reverbatory furnace, before described, and be there well incorporated by
stirring previous to being cast into any desired form in sand or other moulds;
or the pig iron may be first melted in the bath of the reverbatory furnace, or
it may be melted in the cupola furnace and run into the bath of the rever-
batory furnace, after which the heated steel is to be immersed in the fluid iron,
which will protect it during its fusion from the action of the atmosphere and
gases of the furnace. Or in some cases it may be found more convenient to
add the heated steel to the charge of iron in the cupola furnace, in which case
charcoal should be used as fuel. The quantity of steel used with the iron will
be regulated by the quality required in the mixture. After casting, it may be
much softened by annealing, and may, like steel, be hardened by plunging it
into cold water while in a heated state.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Bessemer in the Great Seal Patent Office on the
10th July 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Ann Place, New Cannon Street, in the County of
Middlesex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of January, in the year of our Lord
One thousand eight hundred and fifty-five, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Henry Bessemer, Her special licence that I, the said Henry Bessemer, my
executors, administrators, and assigns, or such others as I, the said Henry

page_text: Bessemer, 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, excrcise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANU-
FACTURE OF IRON AND STEEL," upon the condition (amongst others) that I, the
said Henry Bessemer, by an instrument in writing under my 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 Henry Bessemer, 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):-
My improvements commence at that stage of the manufacture of iron
known as the refining process, and consist in running out the metal from
the finery furnace into large ingots or moulds, having numerous partitions,
for the purpose of facilitating the breaking up of the metal into uniformly
small pieces or bars. Charcoal should be used in the finery furnace, although
coke may be substituted; in either case the process should be carried
further than usual. The ingots of metal so produced (by way of distinction)
I call product No. 1.
In order that the details of the different parts of my said Invention, and
the manner in which the same is to be carried into effect; may be fully
understood, I have hereunto annexed two Sheets of Drawings, marked A
and B. On Sheet A, Figure 4 is a cross section of a cast-iron ingot mould,
suitable for the casting of ingots of fine metal, for the purposes of this
Invention Figure 5 is a plan of the same. The metal in a fluid state is
allowed to flow into any number of such moulds, and to overflow the divisions
a, but not to rise so high as the auter margin b, so that a plate will be formed
having numerous sunk channels formed therein, which will facilitate the
division of it into pieces of uniform size.
When fine metal has been heated in the puddling furnace until it is
reduced to an incoherent state, somewhat like sand, it may be removed
from the furnace, and in this state constitutes product No. 2. The further
working of the iron, and its formation into very small puddle balls, which
are rolled out of the furnace and allowed to cool, I distinguish as product
No. 3. When, however, the puddle balls are made of the usual size, and

page_text: the whole of the process of making bar iron is gone through, I
pass the
bars while still red hot between a pair of rolls, having raised triangular ribs
running lengthwise, by means of which the bar is cut into short pieces of
an uniform size, and in which state it constitutes product No. 4.
The method of puddling refined iron until it assumes the loose and discon-
nected state, herein-before mentioned, and the mode of forming iron in that
state into puddle balls, is so well understood as not to require any particular
description thereof; but the mode by which I cut up bar iron for the
purposes
of this Invention will be better understood by the aid of Drawings. I have
therefore shewn on Sheet A, an end elevation of a pair of rolls at Figure 6 to
be used for this purpose, and a longitudinal elevation of the same at Figure 7.
c, c, c, are raised triangular ribs, formed on the body of the roll, and
extending its whole length in a line with the axis. The rolls are to be fitted
into frames, and driven by gearing in a precisely similar manner to that
adopted in the mounting and driving of rolls used in the manufacture of
bar iron; care, however, must be taken that the rolls are so geared that the
ribs c, c, c, formed on each roll are made to come opposite to each other, and
that the ribs on one roll are not allowed to fall into the intermediate spaces
formed between the ribs of the other. The axis of the upper roll should
also be supported in double brasses, so that when not in use it may be sup-
ported by its lower half brass; it will be readily understood that if a bar of
red-hot iron is passed lengthwise between a pair of rolls so constructed that
it will be cut into pieces, the length of which will be governed by the distance
between the cutting angles of the ribs c, c, c, in Figure 6. A bar of iron dis
represented as passing through the rolls, and being cut into the small pieces,
which I distinguished as product No. 4.
"
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"To these different products may be added a fifth, consisting of boiler-
plate parings, punchings, bar ends, and scrap iron, all of which products,
distinguished as Nos. 1, 2, 3, 4, and 5, are to be converted into steel by the
following processes:-For this purpose, I prepare a furnace very similar in
"its general arrangements to the retort furnaces used in the manufacture of
" gas; into this furnace are placed any convenient number of firo clay or
"other retorts, the open ends of which project several feet through the walls
" of the furnace. Into these retorts are placed a series of iron plates, connected
by iron bars at a distance of about two or three feet apart, somewhat like.
"the buckets in a chain pump. Near to one end of the retorts is placed a
winding apparatus for moving the plates, which are thus made to divide the
" retorts into separate chambers. Into these chambers either of the products
"Nos. 1, 2, 3, 4, or 5 are to be placed, with charcoal powder between and
$$

page_text: "
among them. The partition plates are made to advance, by means of
"the winding apparatus, a small distance' every day, the time occupied in
"their transit through the retorts varying from 6 to 12 days, or thereabout,
according to the thickness of the metal, or to the extent to which the process
"of cementation is desired to be carried; the cooling down of the char-
"coal, and the iron which has been converted into steel by the process, takes
place in the elongation of the retort outside the furnace, which also prevents
the access of air to the materials occupying that part of the retorts which
are exposed to the action of the fire."
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and Figure 3
The furnace
Above the
In order that the method I employ to convert the various products of the
iron manufacture, characterised as products Nos. 1, 2, 3,-4, and 5, into steel
by the process of cementation may be fully understood, I have shewn on
Sheet A of the annexed Drawings at Figure 1 a vertical cross section through
the converting furnace, taken on the line A, B, of Figure 2, which is a hori-
zontal section of the same taken on the line C, D, of Figure 1;
is a longitudinal vertical section on the line E, F, of Figure 2.
has within it four fire grates g. 9, with suitable fire doors at h, h.
fires are placed six cylindrical fire-clay retorts' r, r, similar to the retorts used
in the manufacture of coal gas; these retorts are supported at each end by
the exterior walls of the furnace j,j, and in the middle by the wall k, which
rises as high as the centre of the retorts, and divides the lower part of the
furnace into two parts. i, i, is an arch of fire brick, extending over the upper
surface of the retorts with several openings 1, 1, which allow the products of
combustion after acting upon the retorts to pass into the upper chamber m,
from whence the heated matters find their way by the flue n into the chimney o.
The two ends of each of the retorts rare elongated, by having iron tubular
parts r¹ and fixed or bolted to them, the outer ends of which are supported
on walls p, p. The circular iron plates q, q, have a rod s fastened in the centre
of them, one end of which is provided with a hook and the other end with a
loop, so that they can easily be attached to each other, as shewn in Figure 3.
The brackets t, t, are bolted to the outer wall of the building, or are fixed by
other convenient means in the position shewn. These brackets are for the
purpose of supporting the axle u, on which the chain drums are keyed. One
end of the axle carries a spur wheel w, into which the pinion gears. The
pinion is mounted on a short shaft moving in bearings formed on one of the
brackets.t, and is provided with a handle y, by means of which motion may be
communicated to the axle and drums v. When required, a chain and hook
is fastened at one end to each of the chain drums v, so that when it is desired
to move the plates q, q, through either of the retorts, the chain opposite to the

page_text: retort must be attached to the loop in the outermost rods, and then by turning
the handle y the plates will be caused to move through the retort. By refer-
ence to Fig. 3 it will be seen that a portion of the upper side of the iron
part of the retorts are removed, and that a shelf is formed above them, on
which are placed the materials to be put into the retorts, and which consists of
either of the products Nos. 1, 2, 3, 4, and 5, mixed with coarsely powdered
charcoal or carbonaceous matters. The plates q, q, forin partitions in the
retorts, leaving chambers between them, into which the workmen place-the
said materials; when each chamber is filled from the upper side, where a part
of the retort is cut away, another workman turns the handle y, and thereby
causes the plates q, q, to pass further into the retort, after which another plate
9 may be hooked on and the chamber formed between it, and the preceding
one is in like manner to be filled, and so on, until the whole of the retorts' are
charged. The fires are then urged on until it is judged that the portions of
iron contained in the fire clay part of the retorts are sufficiently charged with
carbon, when the workmen will proceed to move forward the chambers, refilling
at one end of them and discharging their contents at the other, and thus the
process may be carried on continuously without letting out the fire after the
cementation of each charge, as at present practised in the conversion of bar
iron into steel. The time occupied in the transit of the materials through the
retorts will vary with the size and quality of the pieces of iron, the loose
spongy pieces of puddled iron absorbing a sufficient dose of carbon in, a very
much less time than is required for bar or scrap iron that has been rendered
less porous by rolling. If atmospheric air is admitted to the central part of the
retort, it will destroy the charcoal and oxidize the iron; care must therefore
be observed in well filling the chambers at the charging end of the retorts;
also care should be taken that the materials are retained for a sufficient length
of time in the iron part r² of the retorts, so as to lose much of the high tempe-
rature which they have acquired during their transit through that part of the
retorts which is exposed to the action of the fire. The steel produced by this
process will have the general properties of that description of steel known as
blister steel, when any of the products Nos. 2, 3, 4, and 5 are used; but when
product No. 1 is so treated, it will be found to contain a larger quantity of
carbon than steel generally contains, but much less oxide of carbon and other
impurities than pig iron, and will therefore be well suited for many purposes in
the arts, having by the process of cementation given to the iron its required
dose of carbon.
"
"I next proceed to convert the crude steel so produced into cast steel, for
which purpose I employ a reverbratory furnace. The part behind the fire

page_text: **
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"
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bridge is constructed with fire bricks, and forms a shallow basin or bath,
into which I put glass of borax, sal-ammoniac, or other fluxes, combined
with refuse glass, or other vitreous substances, so as to form a fluid uatter
capable of bearing the heat of the furnace, and covering the steel and
keeping it from the injurious influence of the atmosphere and vapours of
the furnace. Any of the products Numbers 1, 2, 3, 4, and 5, after the pro-
cess of cematation, are put into the basin of flux, and are there brought
"to a complete state of fusion; after which the basin may be tapped and
the fluid steel may be cast into ingots for tilting, or it may be formed in
sand or other moulds into numerous articles. In some cases I find it
preferable to use a cupola furnace, such as is commonly employed by iron
founders; in which case charcoal should be used as fuel with hot blast, the
steel, when melted, being run out for the purposes before mentioned.
"Whichever furnace is employed for the melting of the steel, I find it
advantageous to heat the steel in a retort or separate furnace, or in another
"less heated part of the same furnace. I also find it useful in this prelimi-
nary heating to use borax or other flux, as the coating of the steel with
them lessens the oxydation and decarbonization of the steel."
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#5
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Whenever the fusion of steel produced by cementation is to be effected in a
cupola furnace, the surfaces of the steel should be coated with borax, or other
flux or vitreous matters, which may be effected by grinding the substances to
a fine powder and mixing them with water, which may be thrown over the
pieces of steel and allowed to dry upon them; or the steel may be dipped into
the semi-fluid matter, as is practised in glazing pottery ware. A retort or
series of retorts of fire clay should be erected at such a height above the top
of the cupola furnace as will allow the pieces of steel to be brought to a
white heat in them, and then be pushed with a rake through an opening in
the retorts, from which they will fall into the cupola or blast furnace. It will
be understood that the steel during the preliminary heating in the retorts
will be defended from the action of the atmosphere in a great measure by
being placed in a retort or close fire clay chamber, and also by the coating of
flux or vitreous matters, which will have fused and run itself over their
surfaces. It will also be understood how this coating will further protect the
steel from the action of the oxygen during the complete fusion in the cupola
furnace, which will be rapidly effected in consequence of the high temperature
at which the steel is put into it, and the intense heat obtained by hot blast
with charcoal. I have not shown any plans for the retorts or cupola furnace
because no peculiar construction of retort is necessary; any retort, muffle, or
close chamber heated by an external fire may be used, having a feeding hole

page_text: for the purpose of introducing the steel at one end, and a hole in the back
part or bottom of it, through which the heated steel may be pushed out
when required; nor have I shewn any drawings of the cupola furnace to be
employed, as those in general use by iron founders will answer the purposes of
this Invention; but the reverbratory furnace which I use for the purposes
of melting steel has some peculiarities of structure. I have therefore given
Drawings thereof on Sheet B, where Fig. I is a longitudinal vertical section
thereof on the line A, B, of Figure 3; a cross section is shewn at Figure 2,
taken on the line C, D, of Figure 3, which is a horizontal section on the
line E, F, of Figure 1; and Figure 4 is a cross section on the line G, H,
of Figure 3.
a, a, are the outer walls of the furnace; b, the fire grate, which is the widest
part of the furnace, in order that it may contain a large body of fuel, the heat
from which passes over the bath or basin which is narrower than the fire
grate, and thus, becomes exposed to a powerful concentration of flame over its
entire surface; c represents the fluid steel in the bath or basin; and d, the
melted flux or vitreous matters floating on its surface, and thus effectually
excluding it from the atmosphere and gases of the furnace; e, e, are pieces of
steel, receiving 1 preliminary heating previous to being pushed into the bath;
the door f is for the purpose of putting in the steel, and the doors g, g, are
for the purpose of stirring the charge from time to time; h is a peep hole, to
enable the workinen to ascertain the state of the furnace; m is a large door,
supported on a swing frame n, for the purpose of obtaining access to the
interior of the furnace. At the deepest part of the bath there is a tapping
hole, formed at w, on one side of the furnace, which is stopped up during the
fusion of the steel by sand or loam, in the manner usually practised in furnaces
for melting iron. The furnace is strongly bound together by cast-iron binders
r, r, which have wrought-iron tie rods passing through them at their top and
bottom ends; the flues should communicate with a chimney about fifty feet in
height, so as to secure a powerful draught. When it is ascertained that the
steel is melted, the moulds must be brought under the spout t, or a sand gutter
must be formed which leads from the spout t to the moulds, as practised in
iron founding; the loam is then removed from the tapping hole w, and the
fluid steel allowed to run into the moulds. The flux may be retained in
the furnace for the next operation, such additions being made to it as may be
found necessary.
"I have hitherto described my method of treating iron and converting it
" into steel of different qualities, but I desire it to be understood that an

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important part of my said Invention consists in combining the steel so made,
or steel otherwise made, with cast or pig iron, for which purpose the iron
may be melted in an ordinary cupola furnace, and be then run into the
"bath of melted steel in the reverbratory furnace, before described, and be
there well incorporated by stirring, previous to being cast into any desired
form in sand or other moulds; or the pig iron may be first melted in
the bath of the reverbratory furnace, or it may be first melted in the cupola
"furnace, and run into the bath of the reverbratory furnace; after which,.
the steel is to be immersed in the fluid iron, which will protect it during
fusion from the action of the atmosphere and gases of the furnace; or in
some cases it may be found more convenient to add the heated steel to the
charge of iron in the cupola furnace, in which case charcoal should-be used
as fuel. The quantity of steel used with the iron will be regulated by the
"quality required in the mixture. After casting it may be much softened
by annealing, and may, like steel, be hardened by plunging it into cold
"water while in a heated state."
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"
In all cases where a mixture with the steel and iron is effected in the
reverbratory furnace I use a flux or vitreous covering for the metal, as herein-
before described in reference to the melting of steel, and in such cases, as steel
is added to a charge of iron in a cupola furnace, 1 coat the surfaces of such
steel with flux, and give a preliminary heating in a retort or close chamber, as
herein-before described in reference to the melting of steel alone.
.. Having now, described my said Invention, and the manner in which the
same is to be carried into effect, I desire it to be understood that I do not
confine myself to the precise details here given, so long as the peculiar
character of my Invention be retained; but what I do claim is,-.
Firstly, I claim the conversion of ingots or small pieces of refined iron into
steel by cementation with charcoal or other carbonaceous matters in closed
retorts or chambers.
.
A
Secondly, I claim the conversion of puddled iron in a dry or powdery state,
or in a state of small puddle balls, produced as herein described, into steel by
the process of cementation with charcoal or other carbonaceous matters in
closed retorts or chambers.
Thirdly, I claim the progressive or intermittant movement through retorts
or chambers of pieces of iron mixed. with charcoal or other carbonaceous
matters during the conversion of such pieces of iron into steel by the process
of cementation.
Fourthly, I claim the melting of steel in a reverbratory furnace in which

page_text: a basin or bath is formed containing flux or melted vitreous matters, for the
purpose of covering the steel, and protecting it from the injurious action of
the atmosphere and vapours of the furnace.
Fifthly, I claim the melting of steel in a cupola or blast furnace, by the use
of charcoal as fuel, the steel having first been heated in a retort or heated
chamber, and its surface coated with flux or vitreous matters.
Sixthly, I claim the combination by fusion of pig or cast iron with steel.
Seventhly, I claim the fusion of steel in a bath of melted pig or cast iron
in a reverbratory furnace, as herein described.
Eighthly, I claim the combination by fusion of pig or cast iron in a cupola
or blast furnace, the steel having been previously heated in a retort or licated
chamber, and its surface coated with flux or vitreous matters.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Ninth day of July, in the year of our Lord One
thousand eight hundred and fifty-five.
Witness,
B. GOBEY,
4, Old Square, Lincoln's Inn.
HENRY BESSEMER. (L.S.)