IMPROVEMENTS IN THE PROCESSES OF CEMENTATION OR CASE-HARDENING AND SOFTENING IRON
Year: 1860

page_text: LETTERS PATENT to George Davies, of No. 1, Serle Street, Lincoln's Inn,
in the County of Middlesex, and No. 28, St. Enoch Square, in the
City of Glasgow, Civil Engineer and Patent Agent, for the Invention of
"IMPROVEMENTS IN THE PROCESSES OF CEMENTATION OR CASE-HARDENING AND
SOFTENING IRON."-A communication from abroad by Jules Cazanave, of
Paris Manufacturer.
Sealed the 5th March 1861, and dated the 13th September 1860.
PROVISIONAL SPECIFICATION left by the said George Davies at the
Office of the Commissioners of Patents, with his Petition, on the
13th September 1860.
I, GEORGE DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County of
Middlesex, and No. 28, St. Enoch Square, in the City of Glasgow, Civil
Engineer and Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN THE PROCESSES OF CEMENTATION OR CASE-HARDENING
AND SOFTENING IRON," (a communication from abroad by Jules Cazanave, of
Paris, Manufacturer,) to be as follows:-
This Invention has for its object, firstly, the cementation or conversion into
steel of wrought iron of all kinds by means of gases proceeding from different
matters herein-after named; secondly, the cementation of cast iron either
moulded or otherwise; thirdly, the cementation or case-hardening to any
depth required, and at any part of either wrought or cast iron; fourthly, the
[Pic 81

page_text: softening of the most brittle kinds of iron so as to give it almost the malleability
of lead; and fifthly. (by a combination of the above processes) the fabrication
of cylinders, drums, or other articles, which require at the same time great
strength, hardness, and malleability.
The processes are as follows:-For wrought iron a mixture is to be formed
of equal parts of any vegetable and animal matters, the following being pre-
ferred, vizt, for the vegetable matters charcoal, soot, or waste from oleaginous
matters, or waste from spinning cotton, flax, and other similar vegetable
substances, and for the animal substances, woollen rags, woollen waste, flesh,
horn, hide, or other similar waste or refuse animal matters. This mixture is
enclosed in a gas retort in a proportion of from eight to twenty per cent. the
weight of the iron to be converted and according to the quality of the latter,
which is also placed in another vessel or chamber (also closed) in immediate
communication with the gas retort and at the same time with a gasometer,
in order to cause an equal and regular pressure of the gas contained in the
apparatus. The gas retort and the vessel containing the iron are placed over
two furnaces, and the latter is to be heated to nearly a cherry redness, and the
former to a less elevated degree, the gas thus produced (which the Inventor
calls cyanhydrate of ammonia) penetrates the pores of the metal expanded by
the heat and cementation takes place with a rapidity hitherto unknown, and
steel is produced very superior in quality to that made from the same iron
even by the ordinary process.
For cast iron a mixture is to be formed composed of about ninety per cent.
of calcareous matter either mineral or animal added to about ten per cent.
of the mixture already mentioned for the cementation of wrought iron.
The pieces of cast iron are then placed in alternate layers with this mixture
in a closed crucible, and in a few hours according to the thickness, the cast
iron (whether moulded or not) is converted into fine hard steel without the
least alteration in form or otherwise.
For partial cementation of wrought iron articles the part which it is desired
to remain intact is to be covered with mineral or animal calcareous matter,
and the cementation penetrates regularly over all the rest of the piece, which
is in contact with the gas or cementing mixture. For the partial cementation
of cast-iron articles this process must be reversed, that is to say, the parts
required to remain intact must be covered with the cementing mixture for
wrought iron, and the part to be converted must be covered with the mixture
above described for cast iron.
For softening brittle iron the mixture above-named for cast iron, vizt.,
calcareous matters or iron ore is to be used.

page_text: In making cylinders by a combination of these processes, several longitudinal
strips of wrought iron or steel are bound together by hoops or bands placed at
suitable distances apart. The open cylinder thus formed is to be placed in the
mould into which the cast iron is then to be poured or run, and when cold, the
article is to be submitted to the operation above described for cast iron.
⚫ther articles requiring strength,hardness, and malleability may also be thus
formed by placing suitable pieces of wrought iron in the mould previous
to running in the cast iron, and then submitting the same to the operation of
cementation.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Davies in the Great Seal Patent Office on the
13th March 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
DAVIES, of No. 1, Serle Street, Lincoln's Inn, in the County of Middlesex,
and No. 2, St. Enoch Square, in the City of Glasgow, Civil Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of September, in the year of our Lord
One thousand eight hundred and sixty, in the twenty-fourth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
George Davies, Her special licence that I, the said George Davies, my
executors, administrators, and assigns, or such others as I, the said George
Davies, 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, 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 PROCESSES OF CEMENTATION OR CASE-HARDENING AND SOFTENING IRON," being a
communication to me from abroad by Jules Cazanave, of Paris, Manufacturer,
upon the condition (amongst others) that I, the said George Davies, 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 be per-
formed, 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.

page_text: NOW KNOW YE, that I, the said George Davies, do hereby declare the
nature of the 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 in writing, and on reference to the accompanying Drawings, that is
to say:-
This Invention has for its objects, firstly, the cementation or conversion into
steel of wrought iron of all kinds by means of gases proceeding from different
matters herein-after named; secondly, the cementation of cast iron either
moulded or otherwise; thirdly, the cementation or case-hardening to any depth
required,and at any part of either wroughtor cast iron; fourthly, the softening
of the most brittle kinds of iron, so as to give it almost the malleability of
lead; and, fifthly, (by a combination of the above processes,) the fabrication
of cylinders, drams, or other articles which require at the same time great
strength, hardness, and malleability.
The processes are as follows:-For wrought iron a mixture is to be formed
of equal parts of any vegetable and animal matters, either solid, liquid, or
gaseous, containing azote, the following being preferred, namely, for the
vegetable matters charcoal, soot, or waste from oleaginous matters, or waste
from spinning cotton, flax, and otner similar vegetable substances, and for
the animal substances woollen rags, woollen waste, flesh, horn, hide, or other
similar waste or refuse animal matters. This mixture is enclosed in a gas
retort in a proportion of from eight to twenty pr cent. the weight of the iron
to be converted, and according to the quality of the latter, which is also placed
in another vessel or chamber (also closed) in immediate communication with
the gas retort, and at the same time with a gasometer, in order to cause an
equal and regular pressure of the gas contained in the apparatus. The gas
retort and the vessel containing the iron are placed over two furnaces, and the
latter is to be heated to nearly a cherry redness, and the former to a less
elevated degree. The gas thus produced (which the Inventor calls cyan-
hydrate of ammonia) penetrates the pores of the metal expanded by the heat
and cementation takes place with a rapidity hitherto unknown, and steel is
produced very superior in quality to that made from the ame iron even by the
ordinary process.
For cast iron a mixture is to be formed composed of about ninety per cent.
of calcareous matter, either mineral or animal, especially common lime, lime
obtained from the calcined bones of animals, or oyster shells, or even iron
ore. To either of these ingredients previously triturated, is to be added
about ten per cent. of the mixture already mentioned for the cementation of
wrought iron. The pieces of cast iron are then placed in alternate layers with

page_text: this mixture in a closed crucible, and in a few hours, according to the
thickness, the cast iron (whether moulded or not) is converted into fine
hard steel, without the least alteration in form or otherwise.
For partial cementation of wrought-iron articles, the part which it is
desired to remain intact is to be covered with mineral or animal calcareous
matter, and the cementation penetrates regularly over all the rest of the piece,
which is in contact with the gas or cementing mixture. For the partial
cementation of cast-iron articles this process must be reversed, that is to say,
the parts required to remain intact must be covered with the cementing
mixture for wrought-iron, and the part to be converted must be covered
with the mixture above described for cast iron.
For softening brittle iron the mixture above named for cast iron, namely,
calcareous matters or iron ore, is to be used. By these means, in a very few
hours, the most brittle iron is made so pliable and malleable, that it may be
bent and straightened again cold without the least cracking, and is easily filed.
In this manner, and according to the principles of this Invention, iron of very
inferior quality can be softened, so as to be easily worked, and when finished,
as desired, may be brought again to any required degree of hardness.
In making cylinders by a combination of these processes, several longi-
tudinal strips of wrought iron or steel are bound together by hoops or bands,
placed at suitable distances apart. The open cylinder thus formed is to be
placed in the mould, into which the cast iron is then to be poured or run,
and when cold, the article is to be submitted to the operation above described
for cast iron. Other articles requiring strength, hardness, and malleability,
may also be thus formed by placing suitable pieces of heated wrought iron
in the mould previously to running in the cast iron, and then submitting
the same to the operation of cementation.
For the cementation of wrought or cast iron, especially for railway purposes,
the furnaces which the Inventor proposes to employ are composed of
hermetically closed chambers or crucibles, the sides of which are vertical,and
formed of cast or sheet iron, covered on the exterior with a coatingof fire-clay,
to prevent the too great action of the fire thereon. The bottom and cover
of each crucible is made of fire-clay, so formed as made a close joint, and
to be capable of being sealed hermetically by means of clay at the time of
the operation. The covers of the chambers are moveable, and the crucibles
are charged and discharged from above by Deans of a crane or other suit-
able apparatus. When the crucibles are charged and closed, the whole of
the upper part of the furnace is covered in.
The annexed Drawing represents different views of a furnace constructed

page_text: according to this system. Figure 1 represents a vertical section, taken
through about the middle of the furnace; Figure 2 is a horizontal section,
and Figure 3 is an exterior front view of the same. The furnace is composed
of three chambers or crucibles A, A, A, the centre one being about three
times as large as the outside ones. There are four fire-places B, B, B, B, and
the draught is obtained by a series of small flues C, C, C, C, placed at the
sides of the furnace, and each furnished with a separate damper D, to
regulate the draught. These flues descend in the thickness of the walls of
the furnace, as shown in the Drawing, and communicate with two main
flues E, E, which lead to the chimney F, F. Sight holes G, G, are so arranged
as to allow of the of the inspection of the process going on in the crucibles.
The length of the crucibles, and consequently that of the furnace, is deter-
mined by the length of the pieces to be operated on.
which is merely
This gas may be
may be used for
The matters or ingredients used to produce the cementation as above
mentioned are refuse matters merely dried; they are employed alone with-
out any other mixture, and are placed in contact with the iron (to be con-
verted into steel) in the crucibles A, A, A, above named, which are to be
intensely heated, the first gas which is evolved, and
hydrogen, being allowed to escape by a cock or valve.
employed in the fire-places as a means of heating, or it
illuminating purposes. As soon as it is perceived that this gas is no longer
formed, the cock or valve must be closed, and the action of the cyanhydrate
which is then produced effects the cementation in a rapid manner, and gives
a remarkably fine grain to any description of iron. The steel thus produced
when melted may be greatly improved in quality by adding a certain
quantity of resin thereto in the melting pot.
I have above described the means to be employed for preserving from
cementation those parts which it is desired to convert, but this may be
done in a much simpler manner by coating them over by means of a pencil
or brush with a mixture of lime and sand.
When the cementation is produced (whether entire or partial) it is
necessary to temper the articles to give them the necessary hardness,
especially for rails or railway tires or wheels, at the same time preserving
their primitive form. For this purpose the Inventor proposes to use strong
boxes of cast iron, pierced with numerous holes, in order to facilitate the
contact of the water, and the pieces to be tempered are placed therein and
solidly stayed or secured in every direction. These boxes, as soon as they
are charged with the pieces, are instantly plunged into water.
Having now described the nature and object of the said Invention for

page_text: 'Improvements in the Processes of Cementation or Case-hardening and
Softening iron," together with the manner in which the same is to be or
may be performed or carried into practical effect, I would remark, in con-
clusion, that I claim as the Invention communicated to me by the aforesaid
Jules Cazanave,-
Firstly, the process or system of cementation or hardening, and also
softening iron, as above described.
Secondly, the use of the ingredients or materials above named for the
purposes specified.
Thirdly, the employment for such purposes of a furnace constructed and
arranged as before described, and exhibited in the annexed 'rawings.
And, fourthly, the use of a perforated box, as above described, for
the tempering of articles, in the manner herein-before specified.
In witness whereof, I, the said George Davies, have hereunto set my
hand and seal, this Thirteenth day of March, in the year of our Lord
One thousand eight hundred and sixty-one.
GEORGE DAVIES. (L.S.)