IMPROVEMENTS IN THE MANUFACTURE OF STEEL
Year: 1875

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane,
in the County of Middlesex, Patent Agent, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF STEEL."-A communication
from abroad by Jean Eyquem, of Paris, France.
Sealed the 6th July 1875, and dated the 22nd January 18
PROVISIONAL SPECIFICATION left by the said Alexander Melville
Clark at the Office of the Commissioners of Patents, with his
Petition, on the 22nd January 1875.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF STEEL," to
be as follows:-
Among the various theories recently advanced in explanation of the
phenomena attending the steelifying of iron may be mentioned that of
Fremy, the eminent French chemist, according to whom it is to the
simultaneous influence of ammonia gas and carburetted hydrogen gas,

page_text: that iron when sufficiently heated becomes steelified by passing to the
state of azo-carburet of iron.
The object of the present Invention is to produce and to utilize the
above reaction practically in the production of steel on a manufacturing
scalc.
Owing to the difficulty experienced in the employment of gases in
manufacturing processes it is proposed to place the iron to be steelified
in contact with substances capable of producing simultaneously in certain
proportions, ammonia gas and carburetted hydrogen gas on the decom-
position of said substances at a temperature suitable for steelifying iron.
The first substance which I may mention as being suitable for the
purpose is peat, which on being decomposed by heat produces ammonia
and proto-carburetted hydrogen.
By placing bar iron in boxes of fire-clay containing pulverized peat
and well luted, it may be completely converted into steel by heating to
1,292 degrees Fahrenheit, or even less, with much greater rapidity than
by a mixture of gases which have been produced separately or with any
of the cementing materials now in use. The addition of a small
proportion of ammoniacal salt, and more especially the hydrochlorate of
ammonia hastens and renders more perfect the conversion of the iron
into steel. The rapidity of the conversion is explained by the fact that
the ammonia and carburetted hydrogen are in their nascent state in
presence of the iron, and it is well-known how much stronger is their
chemical affinity under these circumstances.
Analogous results may be obtained by the employment of the following
substances, with the addition of sal ammoniac, tan, wood, sawdust,
lignite, coal, resins, mineral oils, fats, liquid or solid hydrocarbons and
animal or other matters capable of producing carburetted hydrogen. As
these matters (liquids among others) are often too energetic to be used
alone they should be diluted with inert powdered substances. I however,
prefer to employ peat and shall in the course of this description refer
only to this substance, although in default of the same it might be
replaced by the other matters above designated.
As before mentioned the steel produced is of excellent quality, and
may be employed for the manufacture of springs, files, and other, tools.
The bars, being manufactured at a relatively low temperature do not

page_text: present that roughness of surface common to ordinary cemented steel to
which is due its name of blistered steel, while the quality of the iron
employed does not sensibly affect that of the steel produced. The fire-
clay or cast-iron boxes in which the bars are enclosed, together with the
5 cement, are placed either in reverberatory or other suitable furnaces.
The continuity and rapidity of the operation and the relatively low
temperature at which it is effected, together with the low price of the
cement, which only requires to be partially renewed after use, all
combine in effecting a considerable saving as compared with the
processes now adopted. Taking advantage of the rapidity with which
the cementation of small pieces of iron is effected I effect in a single
operation both the cementation and the fusion of scrap iron.
I place in a ordinary crucible for melting steel, scrap iron, together
with from 3 to 6 per cent. of peat, according to the nature of the steel it
is desired to produce, and 1 per cent. of sal ammoniac. The crucible is
kept for four hours at a bright red heat and then quickly raised to a
fusing temperature, whereby cast steel of good quality is obtained. This
steel may be produced in a cheaper manner in a reverberatory furnace,
and preferably in a Ponsard or Siemens' furnace, but whichever kind be
employed care should be taken to produce only reducing flames which
are less prejudicial than oxidizing flames.
The following is the method of operation: The furnace is first
charged with scrap and the necessary mixture, the whole being well
rammed down and a layer of pulverized scoria resulting from a similar
operation spread thereon, after which a red heat is maintained for four
hours, and the temperature then raised to the melting point.
The method of preparation of the hearth is the same as in the manu-
facture of puddled steel.
The emergetic reducing action of the gases produced by the peat has
led to the production of steel by treating directly iron orcs and manu-
factured articles rich in this metal and scoria. These materials after
being pulverized are intimately mixed with small peat and from 1 to 1
per cent. of sal ammoniac, and are slowly and gradually heated to fusion,
the product obtained consisting of steel. The gases of the peat have
reduced the iron in the form of sponge, which in presence of these gases
has become cemented and melted. The sulphur, arsenic, and phoshorus

page_text: contained in the matters treated are volatilized and combine with the
hydrogen.
.
It will be readily understood that the proportion of peat to be added
will depend on the composition of the ore, and also on that of the peat
itself, and may vary from 20 to 30 per cent., although experience alone
can decide the necessary quantity required in cach particular case for
effecting the reduction and cementation of the metal. If an excess is
employed a metal is produced which is incapable of being forged, of
great sonority, and especially suited for casting parts of machinery.
The above treatment may be effected in a crucible, but preferably in a
furnace, the same precautions being observed as when treating scrap
iron before referred to. Whether ores or refining slag be treated it is
only necessary to add a layer of scoria as a protection from the flames as
in the former case.
Although the simultaneous action of ammonia and carburetted
hydrogen is indispensable for obtaining a complete and rapid stcelification,
the same effect may also be produced to a lesser extent and in a slower
and less perfect manner by the use of carburetted hydrogen alone.
Hence I reserve the right to use either separately or together the matters
containing hydrogen above specified without the addition of ammoniacal
salt.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Alexander Melville Clark in the Great Seal Patent
Office on the 21st July 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDER
MELVILLE CLARK, of 53, Chancery Lane, in the County of Middlesex,
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of January, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
cighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Alexander Melville Clark, Her special
licence that I, the said Alexander Melville Clark, my executors, admini-
strators, and assigns, or such others as I, the said Alexander Melville

page_text: Clark, 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,
usc, 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 MANUFACTURE OF STEEL," a communication to mo
from abroad by Jean Eyquem, of Paris, France, upon the condition
(amongst others) that I, the said Alexander Melville Clark, 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 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 Alexander Melville Clark, 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, that is to say :-
Among the various theories recently advanced in explanation of the
phenomena attending the steclification of iron, that of Frémy, the
eminent French chemist, appears to be the most in accordance with
the results observed. According to Mr. Frémy, it is under the
simultaneous influence of ammonia and carburetted hydrogen gases,
that iron when sufficiently heated becomes steclified by passing to the
state of azo-carburet of iron.
Now the object of the present Invention is to produce and to utilizo
this reaction practically in the production of steel on a manufacturing.
scale.
Knowing the objections to the direct employment of gases in manu-
facturing processes, it is proposed to place the iron to be stcclified in
contact with substances, which on being decomposed at a temperaturo
suitable for steclifying iron, will produce simultaneously in certain
determinate proportions ammonia gas and carburetted hydrogen gas.
:

page_text: If bar iron be embedded in pulverized peat contained in chests or
boxes made of fire-clay and well luted, the iron will be completely
converted into steel when heated to 700° C (1,292° Fah.), or even less,
with much greater rapidity than with a mixture of gases which have
been separately produced or than by any of the cementing materials now
in use.
The addition of a small proportion of ammoniacal salt, and
more especially the hydrochlorate of ammonia hastens and renders more
perfect the conversion of the iron into steel. The rapidity of the con-
version is explained by the fact that the ammonia and carburetted
hydrogen are in presence of the iron in their nascent state, and there-
fore when their chemical affinity is very strong.
Analogous results may be obtained by the employment of the following
substances with the addition of sal ammoniac, viz., tan, wood, sawdust,
lignite, coal, resins, mineral oils, fats, liquid or solid hydrocarbons, and
animal or other matters capable of yielding carburetted hydrogen. As
these matters cannot always be used alone some of them being liquids
and some too energetic in their action, it is therefore necessary to dilute
them with inert powdered substances. I however, prefer to employ
peat, and shall in the course of this description refer only to this
substance, although in default of the same it might be replaced by the
other matters above designated.
The steel produced as above described is of excellent quality, and may
be employed without being previously refined for the manufacture of
springs, files, and other tools. The bars being manufactured at a
relatively low temperature do not present that roughness of surface
common to ordinary cemented steel to which is due its name of blistered
steel, while the quality of the iron employed does not sensibly affect that
of the steel produced. The fire-clay or cast-iron boxes in which the bars
are enclosed, together with the cement, are placed either in a reverberatory
furnace or in a large muffle furnace, or in a furnace having a movable
sole. The continuity and rapidity of the operation and the relatively
low temperature at which it is effected, together with the low price of
the cement (which only requires to be partially renewed after use) all
combine in effecting a considerable saving as compared with the processes
now in use. Taking advantage of the rapidity with which the
cementation of small picces of iron is effected, I obtain in a single
operation, both the cementation and the fusion of scrap iron.

page_text: To this end I place in an ordinary crucible for melting steel, scrap
iron, together with from 3 to 6 per cent. of peat (according to the nature
of the steel it is desired to produce), and 1 per cent. of sal ammoniac.
The crucible after being placed in the furnace is kept for four hours at a
bright red heat and then quickly raised to a fusing temperature, whereby
cast steel of good quality is obtained. This steel may be produced in a
still cheaper manner in a reverberatory furnace, and preferably in a
Ponsard or Siemens' furnace, but whichever kind be employed care
should be taken to produce only reducing flames which are less prejudicial
than oxidizing flames.
The following is the method of operation:-The sole of the furnace is
first charged with scrap and the necessary mixture, the whole being well
rammed down and a layer of pulverized scoria resulting from a similar
operation spread thereon, a red heat is maintained for four hours, and the
temperature then raised to the melting point, after which the molten
metal is run into a crucible and then into ingot moulds.
The energetic reducing action of the gases produced by the peat has
led me to the production of steel by treating directly iron ores, old iron,
and forge cinder. These materials after being pulverized are intimately
mixed with small peat, and from 1 to 1 per cent. of sal ammoniac and
are slowly and gradually heated to fusion, the product obtained consisting
of steel. The gases of the peat reduce the iron which assumes a spongy
form, and in presence of these gases becomes cemented and melted.
The sulphur, arsenic, and phosphorus contained in the matters treated
arc volatilized and combine with the hydrogen.
It will be readily understood that the proportion of peat to be added
will depend on the composition of the orc, and also on that of the peat
itself, and may vary from 20 to 30 per cent., although experience alone
can decide the necessary quantity required in each particular case for
effecting the reduction and cementation of the metal. If an excess is
employed a metal is produced which is incapable of being forged,
possesses great sonority, and is especially suited for casting parts of
machinery.
.
The above treatment may be effected in a crucible, but preferably in
a reverberatory furnace, the same precautions being observed as when
treating scrap iron before referred to. Whether ores or forge cinder be
treated it is only necessary to add a layer of scoria as a protection from
the flames as in the former case.

page_text: 2ndly. The manufacture of cast steel from scrap iron by cementing
the scrap iron as above described, and fusing it in one and the same
operation as specified.
3rd. The manufacture of steel by the fusion of iron sponge cemented
by the above described process, said sponge having been formed by the
reduction of ores, old iron, or forge cinder by the gases produced from
peat or other matters containing hydrogen enumerated under clause 1,
all as herein-before described.
In witness whereof, I, the said Alexander Melville Clark, have
hereunto set my hand and seal, this Twenty-first day of July,
in the year of our Lord One thousand eight hundred. and