IMPROVEMENTS IN THE TREATMENT AND MANUFACTURE OF IRON AND STEEL
Year: 1866

page_text: LETTERS PATENT to John Calvert, of the Strand, in the County of
Middlesex, Civil Engineer, for the Invention of "IMPROVEMENTS IN THE
TREATMENT AND MANUFACTURE OF IRON AND STEEL."
Sealed the 22nd March 1867, and dated the 24th September 1866.
PROVISIONAL SPECIFICATION left by the said John Calvert at the
Office of the Commissioners of Patents, with his Petition, on the:
24th September 1866.
1, JOHN CALVERT, of the Strand, in the County of Middlesex, Civili
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN THE TREATMENT AND MANUFACTURE OF IRON AND STEEL," to be as
follows:-
This Invention consists in eertain improvements in the treatment of iron,
whereby it is manufactured or converted into iron possessing welding properties
of a high order or into steel in a simple and economical manner.
In the metallurgical treatment of iron with a view to render it especially
adapted for the purposes of welding or for the production of steel, it is essential
that the several particles of which the mass is composed should be entirely
under the controul of the operator, in order that they may be respectively.
subjected to those influences which are instrumental in producing the desired

page_text: result. Thus in the "pneumatic" or "Bessemer" process the partial contact of
the iron with the atmospheric air which is introduced into the converting
vessel, however it may assist in effecting the change of character which is sought
to be obtained, yet it is also desirable that the iron should be retained in a
finely divided state until all the chemical and electrical changes necessary for
the production either of iron or steel of the required quality have taken
place.
By the present Invention the advantages derivable from the last-mentioned
condition are fully obtained. In order to prepare the iron for the necessary
subsequent treatment it should be in the first instance brought into thorough
contact with oxygen, either in its pure state or as it exists in the atmosphere,
whereby it obtains the benefit of the chemical and electric influences of
the same.
To effect this contact the iron is reduced to a state of powder or fine
division whilst at a red heat by means of any suitable mechanical appliances,
the iron being when thus disintegrated or reduced to a state of fine division
thoroughly under the controul of the operator for the purposes of this Invention.
This operation of disintegration may, if necessary, be repeated, and it may be
desirable in some cases to immerse the disintegrated iron in a bath consisting
of water or of one or other of the solutions herein-after mentioned. In order
to impart or develope the amount of magnetism to or in the iron requisite for
the constitution of the crystalline or grained structure which is essential to
produce the degree of strength desired, and also to assist in the further
cleansing or purifying of the same, the finely divided iron may, if necessary,
be subjected to such influences as will produce the requisite polarity in the
several particles thereof, if the same have not originally possessed such
polarity or acquired the same during the operations to which the iron has been
subjected. This is effected by placing the finely divided iron, either in a
heated or cold state, in contact with iron which has been permanently or
electrically magnetised, or by passing an electric current through the mass
during treatment, or by agitating the iron by means of any suitable apparatus
so as to produce a considerable amount of friction by the particles rubbing
against each other; or the finely divided iron may be caused to fall from a
considerable height through the atmosphere, the result being that the several
particles acquire the requisite polarity. In some cases the iron may, when it
has been thus treated, be conveyed at once to the furnace and heated as
herein-after mentioned, but with some descriptions of iron it is necessary to
subject them to the influence of gases or chemical solutions, so as to impart
thereto such a constitution as is requisite for their conversion.

page_text: The nature of the gases or solutions necessary to be so employed must of
course vary and depend upon the chemical constitution and nature of the iron
under treatment, and the character of the elements which it is desired to
impart to or abstract from the iron in order to arrive at the desired results,
as will be well understood by persons conversant with chemical and metallurgical
operations. As examples of the gases which may be so used,. carbonic acid
gas, carbonic oxide, oxygen, and hydrogen may be enumerated, whilst cyanide
of potassium and carbonate of lime in solution may be cited in illustration of
the liquid selutions which may be employed. The iron having been, as
previously mentioned, treated whilst in a state of minute division, and
consequently entirely and thoroughly under the controul of the operator, every
separate particle thereof is subjected to the influence and action of the processes
before referred to, and the mass is thereby fitted for the next operation, which
consists in introducing the iron into a furnace in which it is brought to a
welding heat. Upon being removed from the furnace and subjected to rolling
apparatus or welding hammers it will be found that the peculiar grain and
crystalline structure characteristic of strength has been developed in the iron,
such change being due to the magnetic and other properties which have been
imparted to or developed in it by the before-mentioned. treatment. The
character and quality of the iron or steel thus produced will of course depend
upon the composition of the iron employed. In those instances in which the
result obtained is iron possessing the properties of steel it will be found that
the whole mass is thoroughly converted, and that the change is not merely
external and superficial, as is the case in the methods frequently adopted..
One chief advantage arising from the treatment embraced by this Invention:
is that the "grain" and crystalline structure, which are absolutely essential to.
produce the requisite degree of strength in iron and steel, are obtained with
much greater precision and certainty than by the processes hitherto used..
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Calvert in the Great Seal Patent Office on the 23rd
March 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CALVERT, of the Strand, in the County of Middlesex, Civil Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fourth day of September, in the year of

page_text: our Lord One thousand eight hundred and sixty-six, in the thirtieth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
him, the said John Calvert, Her special licence that he, the said John Calvert,
his executors, administrators, and assigns, or such others as he, the said John
Calvert, his 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, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE TREATMENT
AND MANUFACTURE OF IRON AND STEEL," upon the condition (amongst others)
that I, the said John Calvert, my executors or administrators, by an instru-
ment 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 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 Calvert, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, that is to say:-
My said Invention consists in certain improvements in the treatment of
iron, whereby it is manufactured or converted into iron possessing welding
properties of a high order or into steel of the best quality in a simple, effectual,
and economical manner.
Before describing the processes which constitute my said Invention, I will
make some observations which will tend to elucidate the principles upon which
it is based.
Iron has but little affinity for "ör inclination to form alloys and chemical
combinations with metals and many substances, and therefore when subjected
to the influence of heat it will generally disengage itself from its chemical
combination with other metals or substances, which will be wholly expelled
or be retained only in mechanical mixture with the iron.
Iron crystallises when cooling or when under the influence of percussion or
vibration, or of electric or magnetic currents, and is always more or less
cellular (polythallamic). Such crystallisation may be divided into four classes.
The first kind (placoidean) is that which occurs in iron which is comparatively
pure, such as meteoric iron. The second kind of crystallisation (sphenoidean)
may be compared to that which 'exists in granite, the crystals being perceptible
to the eye. Both the last-mentioned forms of crystallisation produce iron

page_text: which does not possess much strength. The third variety of crystallisation
(poikiloidean) may be compared to porphyry, as the crystals are imbedded in
the surrounding matters. This is the most impure of all descriptions of iron,
owing to a large admixture of foreign substances and impurities which are
more or less imperfectly melted, and is but little adapted for the purposes of
manufacture. The presence of titanium and other metals of a similar refrac-
tory nature often produces this quality of iron. Iron which is the subject of
the fourth class of crystallisation (sertecoidean) may be termed homogeneous,
as the facets of the crystals are not visible to the naked eye, the expansion of
the cells throughout the iron having effaced or pressed out the very small
crystals of which the iron consists; this description of iron is of the strongest
character, and the best steels may be included under this head.
In the process of smelting, the iron, as it runs out of the blast furnace, is
completely honeycombed with hollow cells, which, owing to the lateral resistance
being the greatest, become slightly elongated in accordance with the shape of
the pig, but if the iron ran out without meeting with the resistance which is
given by the sides of the mould the cells would be perfectly spherical and in
their true normal condition. The carbon contained in the iron in this state is
nearly all held in chemical combination, and in consequence the iron ought to
cool as it leaves the blast furnace, inasmuch as the carbon is so hot that it
will go off. before the impurities combined with the iron can be got rid of, for
as carbon has a great affinity for oxygen at a white heat, it will when in that
condition deprive silex, phosphorus, and sulphur of their oxygen, or will
prevent their oxidation, thus lessening the cleansing power of the oxygen to
deal with the mass under treatment.
In the metallurgical treatment of iron with a view to render it especially
adapted for the purposes of welding or for the production of steel it is essential
that the several particles of which the mass is composed should be entirely
under the control of the operator, in order that they may be respectively
subjected to those influences which are instrumental in producing the desired
result. Thus in the "pneumatic" or "Bessemer" process the partial contact
of the iron with the atmospheric air which is introduced into the converting
vessel, however it may assist in effecting the change of character which is
sought to be obtained, yet it is also desirable that the iron should
be retained in a finely divided state until all the chemical and electrical
changes necessary for the production either of iron or steel of the
required quality have taken place. By the pneumatic process the best
descriptions of pig iron only can be used, as the metal is decarbonised too"
rapidly to allow of its being freed from the sulphur and phosphorus and

page_text: other impurities, whilst a part of my present Invention is important, inasmuch
as inferior kinds of metal may be retained at a low heat until they are
tolerably well cleansed.
In order to prepare the iron for the necessary subsequent treatment, and to
cleanse it from the various foreign substances with which it is combined, it should
be brought to a red heat, so that the carbon shall be partially retained until
the iron shall have been cleansed from the other impurities, for which purpose,
and to prepare it for the necessary subsequent treatment, it should be in the
first instance brought into thorough contact with oxygen, either in its pure
state or as it exists in the atmosphere, whereby it obtains the benefit of the
chemical and electric influences of the same; to effect this contact the iron is
reduced to a state of powder or fine division whilst at a red heat by means of
any suitable mechanical appliances, such, for instance, as revolving circular
saws, which I will, for the purposes of description and explanation, assume as
being used. The circular saws are rigidly braced together and nearly touch
one another, and are set to revolve, at about one-sixteenth of an inch out of
gear. Great care must be taken that the pig shall not cool, as it would in
that case break the saws. The revolving saws may during the course of each
revolution, according to the temperature required, touch or become partially
immersed in water or cold sand. Whilst the saws are disintegrating the iron
or exposing its particles to the oxygen of the atmosphere purification of the
iron is rapidly taking place, for as each particle of iron becomes liberated by
the saws it will immediately absorb oxygen, and if allowed to do so will
increase in temperature, and even appear to explode, more especially if
oxygen in excess be added to the atmosphere through which the red hot
particles of iron fall. It will be evident that the temperature to which the
iron shall be exposed will be entirely under the control of the operator, and
if the pig be very impure, or contain much sulphur, phosphorus, or silicon,
it will be manifest that the temperature should not be increased above a red
heat; or, on the other hand, with metal of greater purity, a very high degree
of heat may be obtained through the medium of oxygen.
In some cases it may be necessary to repeat the operation of disintegration
and to allow the red hot particles to fall into water or to subject them to the
influence of gases or chemical solutions. The nature of the gases or solutions
necessary to be so employed must, of course, vary and depend upon the
chemical constitution and nature of the iron under treatment and the character
of the elements which it is desired to impart to or abstract from the iron in
order to arrive at the desired results, as will be well understood by persons
conversant with chemical and metallurgical operations; as examples of the

page_text: gases which may be so used carbonic acid gas, carbónic oxide, oxygen, and
bydrogen may be enumerated, whilst cyanide of potassium and carbonate of
lime in solution may be cited in illustration of the liquid solutions which may
be employed. In cases in which it may be found necessary to retain the
particles of iron at a red heat for any considerable length of time for the
purpose of getting rid of impurities, the red hot particles may be so arranged
that they shall fall on to the hearth of a reverberatory or other suitable
furnace, and being there kept the desired length of time at a red heat the
particles may be allowed to agglomerate together into balls, which they will
readily do.
In order to impart or develope the amount of magnetism to or in
the iron requisite for the constitution of the crystalline or grained structure
which is essential to produce the degree of strength desired, and also to assist
in the further cleansing or purifying of the same, the finely divided iron
should be subjected to such influences as will produce the requisite polarity in
the several particles thereof, if the same have not originally possessed such
polarity or acquired the same during the operations to which the iron has been
subjected. This is effected by placing the finely divided iron, either in a heated
or cold state, in contact with iron which has been permanently or electrically
magnetised, or by passing an electric current through the mass during treat-
ment, or by agitating the iron by means of any suitable apparatus so as to
produce a considerable amount of friction by the particles rubbing against each
other, or the finely divided iron may be caused to fall from a considerable
height through the atmosphere, the result being that the several particles
acquire the requisite polarity. The iron having been, as herein-before
mentioned, treated whilst in a state of minute division, and consequently
entirely and thoroughly under the control of the operator, the mass is thereby
fitted for introduction into the furnace in which it is brought to a welding
heat. The iron should then be subjected to the rolling apparatus or welding
haminers before it is suffered to cool, for the normal cellular structure of the
iron being spherical the cells require to be slightly collapsed and to take a
more elongated form, and which would never be perfectly uniform throughout
the mass the iron were allowed to cool before being subjected to the necessary
pressure, as foreign matters, such as, for instance, free carbon in the form of
graphite and titanium (when that metal is in combination with the iron under
treatment), will from their partial non-affinity to the iron partly occupy the
cells. At this stage of the process a strong malleable iron is obtained, in which
the carbon which is still retained is chiefly in mechanical combination, the cells
being nearly filled with the graphite and other substances as before mentioned.
The iron is now very much purified and suitable for drawing or welding or for

page_text: the process of conversion into steel, and will be found to possess the peculiar
grain and crystalline structure characteristic of strength, such change being
due to the magnetic and other properties which have been imparted to or
developed in it by the before-mentioned treatment. If, during the process of
purification, too much carbon shall have escaped from the iron, then, if the
conversion of the latter into steel be intended, carbon must be added thereto,
either by the addition of powdered graphite sprinkled over the mass during
the process of "balling" or otherwise, or by any other known and suitable
method; or boron, either in the form of borax, boracic acid, or in other
chemical combination, may be introduced at this or other stages of the
manipulation, either independently of the carbon or otherwise. In order to
form steel from the malleable iron in which the carbon exists in mechanical
union it is necessary to cause a portion of the carbon to recombine chemically
with the iron, which it will do simultaneously with the compression or
collapsing of the elongated cells, and which may be effected by means of a
succession of percussive blows, or by the sudden application of cold to the
heated mass, or by the known methods of carburization. The strongest
description of steel as at present manufactured is a chemical combination of
carbon and iron with a small per-centage of one or more foreign metals, such
as manganese, titanium, or silicon, in alloy with the iron, such alloy having
mechanically combined therewith a sufficiency of foreign matter to partially
occupy and fill the cells and to protect them from total collapse. What is
required for the production of steel of the best quality is a combination there-
with of a substance or substances harder than itself, such, for example, as
carbon or boron and the metals which will come next in succession according
to their relative hardness, but it is also requisite that some hard substance
should occupy the cells or portions of the cells in the minutest mechanical
division for the purpose of imparting rigidity to the mass; crystallised carbon
(diamond) or crystallised boron I consider to be the best adapted for this
purpose; carbon in the state of graphite will be of little use except in articles
of inferior quality, therefore to crystallise some portion of the carbon or boron
chemically present in the steel is what I aim at. The previous treatment of
the iron has been preparing it by a succession of stages, and now the aid of
electricity is again called in to assist the operation. Having at an early stage
of the process polarised the iron as before mentioned it is now more susceptible
to the action of an electric current to which it may be subjected, such electric
current being caused to pass through the mass whilst under treatment. The
current must be adapted to the slow process of carburetting or be employed
simultaneously with percussion or with the compression arising from the sudden

page_text: application of a cooling agent. Great care must be taken that the heat
engendered by the force of sudden collapse caused by change from beat to cold
or hammer blows shall not be neutralised by its own agency. By the means
herein-before described the strongest quality of steel is produced, its
superiority being chiefly owing to the compressed cells of the steel being more
or less filled with crystallised carbon (diamond), boron, or other hard
substances, instead of carbon being retained in the cell in the form of graphite
as heretofore.
Having thus fully declared and ascertained the nature of my said Invention,
and the manner in which it is to be performed, I would observe in conclusion
that what I consider novel and original, and therefore claim as being the
Invention secured to me by the said herein-before in part recited Letters
Patent are,
First, the employment of crystallised carbon in the manufacture of steel, as
herein-before described and set forth.
Secondly, the use and application of boron in the manufacture of steel, as
herein-before described and set forth.
And, thirdly, the treatment and manufacture of iron and steel in the manner
and by the processes substantially herein-before set forth and described, or any
mere modifications thereof.
In witness whereof, I, the said John Calvert, have hereunto set my
hand and seal, this Twenty-third day of March, in the year of our Lord
One thousand eight hundred and sixty-seven.
Witness,
E. P. H. VAUGHAN,
54, Chancery Lane,
Agent for the Patentee.
JOHN CALVERT. (LB.)