IMPROVEMENTS IN CONVERTING IRON INTO STEEL, AND IN GIVING A COATING OF STEEL TO IRON
Year: 1856

page_text: LETTERS PATENT to Christopher Binks, of the City of London, in the
County of Middlesex, for the Invention of "IMPROVEMENTS IN CONVERTING
IRON INTO STEEL, AND IN GIVING A COATING OF STEEL TO IRON."
Sealed the 12th May 1857, and dated the 14th November 1856.
PROVISIONAL SPECIFICATION left by the said Christopher Binks at the
Office of the Commissioners of Patents, with his Petition, on the 14th
November 1856.
I, CHRISTOPHER BINKS, of the City of London, in the County of Middlesex,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
CONVERTING IRON INTO STEEL, AND IN GIVING. A COATING OF STEEL TO IRON,"
to be as follows:-
My said Invention consists in converting masses of iron into steel, either
wholly or superficially, by the use and application of certain cyanogen com-
pounds or other materials containing and capable of imparting to the iron
both nitrogen and carbon, or either, according to the quality or composition
of the iron operated upon; such converting compounds or materials being
sprinkled upon or otherwise applied to the surface of the iron as it passes
through the rolling mill or under the hammer, or is subjected to a mechanical
action of any other kind, whereby fresh surfaces of the metal are developed
and presented to the action of the converting compound, till it either wholly
or partially converts the iron into steel.

page_text: It consists further, in effecting the (so called) cementation of iron in its
conversion into steel, namely, by exposing the iron to the action of cortain
compounds of cyanogen or of other materials containing and capable of
yielding to the heated metal the elements nitrogen and carbon, for its
complete conversion into steel.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Christopher Binks in the Great Seal Patent Office
on the 14th May 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHRISTOPHER
BINKS, of the City of London, in the County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of November, in the year of our Lord
One thousand eight hundred and fifty-six, in the twentieth year of Her reign,
did, for Herself, er heirs and successors, give and grant unto me, the said
Christopher Binks, Her special licence that I, the said Christopher Binks, my
executors, administrators, and assigns, or such others as 1, thesaid Christopher
Binks, my exccutors, 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 "IMPROVEMENTS IN CON-
VERTING IRON INTO STEEL, AND IN GIVING A COATING OF STEEL TO IRON," upon the
condition (amongst others) that I, the said Christopher Binks, 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 bo 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 Christopher Binks, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement :-
It has been long known that the application to the surface of heated iron of
certain compounds in which the elements carbon and nitrogen, or nitrogen and
hydrogen, are essential constituents, (as for example, the ferrocyanide of
potassium and muriate of ammonia,) results in the case-hardening of the iron,

page_text: or, in fact, in the instantaneous formation upon the surface of the iron of a
layer of steel. The application of these reactions has hitherto been confined
to the case-hardening of iron or of soft steel, that is, to the producing upon the
surface of the iron a thin film of steel, or the effecting upon the surface of soft
steel, or imperfectly converted iron, its more complete conversion into steel.
It has also been long known that the conversion of iron into steel, when
that conversion is effected under the (so called) cementation process, is greatly
facilitated when to the charcoal usually employed in such process there is
added some azotised compound and some saline matters, as when, along with
the charcoal in which the iron to be converted is imbedded, there is mixed (for
example) horn or leather shavings, or animal charcoal, or one or other of these,
mixed, as is sometimes done, with common salt or with some other alkaline
matter. It has also been long known that when gaseous cyanogen or some
volatile compound of cyanogen is brought in contact with heated iron, the
result is its conversion, either partially or completely, into steel. Now, the
first part of my Invention is founded upon the well-known fact above referred
to, of the instantaneous production of steel as a consequence of the reactions
at the points of contact between the heated metal and these carbon and
nitrogen or nitrogen and hydrogen compounds, the application of either or of
both producing steel according to the special condition of the iron. And this
part of my Invention consists of operations, under which this instantaneous
formation of steel superficially is so applied or extended as to result in the
production of masses of steel, or in effecting upon any given quantity of iron
its more complete conversion into steel than that merely superficial conversion
called case-hardening, as that has hitherto been effected and practiced. And
in general terms, this part of my Invention consists in the employment of
mechanical force applied to the iron, conjointly and simultaneously with the
application to it of the before-named converting compounds (or others herein-
after specified), in order to give to the iron an extended surface, or to present
to the action of the converting agent so many surfaces in succession as shall
finally bring the whole of any mass of metal in contact with or under the
action of the converting agent, and result finally in its partial or complete
conversion into steel, or in giving to it those properties or elements essential
and peculiar to steel.
The means I prefer to employ for accomplishing this are as follow,
namely: First, the mass of iron to be converted into steel is made red or
white hot, and then passed between rollers to form it into bars, rods, plates,
or sheets, or into any other shapes, in assuming which its surface is extended
or changed, and a series of fresh surfaces from time to time developed. As

page_text: the iron passes through the rolling mill, ferrocyanide of potassium, or some
other converting compound, is sprinkled over its surface, or is otherwise
brought in contact with the successively developed surfaces of the heated
metal. The result is the conversion of the metal into steel, more or less
complete, according to the length of time of contact between it and the
converting compound, or according to the relation between the length of time
of action of the converting compound and the bulk or thickness of the mass of
iron upon whose surface it is brought to act. The sheet, or plate, or bar
of steel so produced is in this form applicable to many purposes, but it may
now be cut up into pieces, and melted in crucibles in the usual manner into a
homogenous mass of cast steel, or it may be rolled or doubled up,again heated,
and thou welded, or be rolled, or hammered, or otherwise formed into bars or
other shapes. And the converting compound may, if needed, during this
robeating and rolling, or hammering and welding, be reapplied to the metal.
Or, in the first instance, instead of carrying out this mechanical development
of its surface to the extend of producing thin plates or sheets, this operation
may stop when bars similar to ordinary shear steel bars have been formed,
and then these may be "faggotted," reheated, and welded into a mass under
the tilting hammer, with fresh applications from time to time of the converting
compound.
Instead of beginning as just described with masses of iron, and applying the
converting compound as the surfaces are being developed, I vary the operation
by beginning with sheets of iron already formed, or with other forms of the
iron that present extended surfaces, and which have previously been formed;
for instance, I take iron in the form of plates or sheets, which I make red
or white hot, and then sprinkle over them, or otherwise bring in contact with
them the converting compound, as by dipping in a melted bath of some fusible
cyanogen compound, which then either completely, or more or less completely,
according to the length of time or contact, converts the iron into steel. To
make this into a homogenous mass of steel, or into cast steel, the plate or
sheet is either cut up and then melted in a crucible, or is rolled or doubled up,
reheated, and rolled, hammered, or tilted and welded into a solid mass, with
further applications or reapplications (if needed) of the converting compound
as these secondary operations are boing proceeded with.
I prefer, however, the first-described method, i. e., from the beginning
operating upon a heated ingot or mass, to combine together the mechanical
and the chemical action, or to effect the extension or development of surface
of the mass and the action of the converting compound simultaneously.
In some cases (using the tilting hammer or any other contrivance that sub-

page_text: serves a similar purpose) I take a mass of strongly heated, softened, or semi-
fluid iron, similar, for example, to a bloom or ball, or to that obtained from
the ordinary puddling furnace, and placing this under the hammer, and
sprinkling over it the converting compound as the action of the hammer
throws out or developes fresh surfaces, keeping up such operations so long as
the temperature of the mass permits of fresh surfaces being thrown up, and in
this manner effect its conversion into steel. Such a mass may require to be
reheated and retouched with the converting compound more than once before
its conversion be complete; but the result is the production, in a compara-
tively short space of time, of a mass of steel of a quality corresponding with
the quality of the original iron. It is desirable, but not absolutely necessary,
to note the exact composition of the iron operated upon, in order to apply to
it exactly the kind of converting compound its special character may require.
If the iron be good malleable iron, or well puddled iron, and consequently
comparatively free from carbon, it requires for its conversion a compound cou-
taining both carbon and nitrogen. If it be ordinary charcoal pig iron,
containing the usual proportion of carbon, it needs only a compound contain-
ing nitrogen, but one not necessarily contaiuing also carbon. Therefore, in the
one case may be applied (for example) some salt of ammonia or other suit-
able nitrogenizing element, whilst in the other case the application of some
compound containing both carbon and nitrogen is essential.
The compounds I prefer under this part of my Invention to employ as the
nitrogen and carbon-giving agents (besides those hitherto so long known and
used to give to heated iron the superficial coating of steel called "case
hardening") are the cyanides of sodium, or of potassium, or of calcium, or
of iron, or of manganese, or the ferrocyanides or farrideyanides of these; but
preferably I employ those that fuse at a red heat, or that can be made into
fusible mixtures by addition to them of some alkaline matter, as the
carbonate of soda or of potash.
And what I claim as my Invention is, the conversion of iron into steel by
the use of cyanogen or ammoniacal compounds, or a mixture of their
elementary constituents, in combination with mechanical agency, applied to
bring them in contact with the surface or progressively developed surfaces
of the metal, as above described.
My Invention in the second place consists in the application of the pre-
viously described method of producing or forming a coating of steel upon
iron, to the producing upon the surface of certain manufactured iron articles
a coating of steel during the process of manufacturing, or the rolling, or
forging, or otherwise shaping of such articles.

page_text: The articles in iron more particularly referred to are such as receive their
final shape or formu when the metal is red or white hot, by passing the hot
metal through rollers, or by pressuro, or hammering, or forging, and to which
articles, the better to adapt them to their after uses, it is desirable to give a
hard or steel coating, extending to a greater or less depth from and below the
surface, but not necessary to have such steeling or hardening to extend
throughout the whole mass; as, for instance, railway bars, the tires of railway
and other wheels, lathe and other spindles,'centre pins, studs, cams for tilting,
horse-shoes, and pick-axes, &c., &c., &c. And this part of iny Invention con-
sists in sprinkling over the surface, or in otherwise bringing in contact with
the surface of such heated metal of which such articles are being formed, one or
other of the converting materials above specified, as the hot metal passes
through the shaping roller, or through the press, or under the hammer, or
through the process of forging it, in the manufacture of such articles.
As in the former instance, the converting ngonts I prefer to employ in this
process are such of the nitrogen and carbon or cyanogen compounds as melt
at a red heat and flow readily over the surface of the metal; and of these I
prefer the ferrocyanide of sodium, rendered more fusible by addition to it of
carbonate of soda, but do not confine my Invention to the use by such only.
The articles, after being so converted at their surfaces, and having so received
their final form from the hammers or rolls, are to be plunged into water
holding in solution some nitrogen and carbon,or nitrogen and hydrogen com-
pound, and preferably, into a solution of cyanide of potassium, or cyanide of
sodium, or cyanogen gas, or hydrocianate of ammonia. By this treatment the
rails (for example) are first partially converted into steel, being covered with a
superficial coating of it, and are next by this dipping tempered or case-
hardened in a most efficient manner. What I claim under this head of my
Invention is, the producing upon articles, as they are being shaped or manu-
factured, a coating of steel, in the manner herein-before described.
My Invention, in the third place, relates to improvements upon the (80
called) cementation process, for converting iron into steel, that is, improve-
ments upon
that process, , which in principlo depends upon producing changes
in the constitution or composition of iron, that, beginning at the surface, are
propagated or diffused throughout the whole of any mass of metal, and result
in its assumption of the peculiar properties of steel. The reactions produced
by the application to heated iron of the nitrogen and carbon or cyanogen com-
pounds, or, according to the actual condition of the metal, or ammoniacal
compounds that have been previously herein referred to, have been resorted to
hitherto merely to obtain upon the metal a superficial coating of steel. But if

page_text: this application, or the period of time of contact between the metal and such
converting compounds, be prolonged beyond that required to produce merely
a superficial coating, iben such reactions carry their effects beyond the
mere surface, and extend themselves from that to a greater or less depth
within the mass, or so far as to permeate the whole mass of iron, and effect
its complete conversion into steel.
Now, this part of my Invention consists, first, in the use of arrangements
by which this converting action of the previously mentioned compounds is
kept up and continued as long as needful for it to extend itself throughout
the entire substance of any mass of iron to which such application is made,
and consequently to effect complete conversion of the iron into steel. Of
the several compounds that may be used as couverting agents under this
method, I prefer to employ the ferrocyanide of sodium, either alone or
mixed with some alkaline carbonate, preferably, the carbonate of soda, in
order to give greater fluidity to it when fused at the red or higher heat
under which it is applied to the iron.
Practically the iron to be converted (for example. bars or rods of malleable
irou,) are packed or imbedded in the converting compound contained in a
retort or box, heated externally and sufficiently close to be preserved from any
free access of atmospheric air, but with some outlet or opening to admit of the
escape of any volatile or gaseous matter that may be evolved during the pro-
cess. The length of time of conversion will depend upon the bulk or mass of
iron to be changed; but I find practically, that bars of iron of the thickness of
those usually placed in common cementing furnaces for conversion, are fully
changed into steel in from six to twelve hours by this method.
Secondly, this part of my Invention consists in admitting to the charcoal
used in the ordinary cementation process, atmospheric air, by means of small
apertures or holes made in the boxes, in which are packed the bars of iron
and the charcoal under the ordinary cementation process, such holes or
apertures being just large enough and so placed as to permit or cause
atmospheric air to pass in and permeate the heated mass of charcoal, but
without creating any material combustion of the charcoal. By this means
there is presented to the iron a heated atmosphere of uitrogen and of carbonic
oxide during the process of cementation or conversion.
A convenient kind of apparatus in which to carry on this operation consists
of an iron retort, heated externally, in which are placed the iron to be con-
verted and the charcoal, and through which is drawn or forced, by any conve-
nient contrivance, a gentle ourrent ofatmospheric air, in quantityjust sufficient
to maintain within the retort an atmosphere of nitrogen and carbonic oxide.

page_text: I
vary
the operation advantageously in some cases, by admitting instead
of air, ammonia or some volatile compound of ammonia, which, under the
high temperature and reaction with the excess of carbon present, gives rise
to the formation, in contact with the iron, of a nitrogen and carbon
atmosphere, and consisting variously (according to conditions as to relative
quantities and temperature) of a mixture of cyanogen, carburetted hydrogen,
and oxides of carbon, the contact of which with the iron results in its
greatly facilitated conversion into steel.
What I claim in respect of this part of my Invention is, first, the use of
fusible compounds of cyanogen, in which to imbed iron, in order to effect
its conversion into steel.
Secondly, the admission of atmospheric air, or of ammonia, or of some
ammoniacal compound, to the charcoal and iron in the furnace employed
for converting iron into steel, as above described.
In witness whereof, I, the said Christopher Binks, have hereunto set
my hand and seal, this Fourteenth day of May, in the year of our
Lord One thousand eight hundred and fifty-seven.
CRISTOPHER BINKS. (L.B.)
Signed by the within-named Christopher
Binks, in the presence of
HENRY FLETCHER, Patent Agent,
123, Chancery Lane, London.