IM- PROVEMENTS IN THE MANUFACTURE OF STEEL
Year: 1861

page_text: LETTERS PATENT to William Clark, of 53, Chancery Lane, in the County
of Middlesex, Engineer & Patent Agent, for the Invention of "IM-
PROVEMENTS IN THE MANUFACTURE OF STEEL."-A communication from
abroad by Messrs. Louis Joseph Frédéric Margueritte and Alfred Lalouël
de Sourdeval, both of 29, Boulevart St. Martin, Paris, in the Empire of
France.
Sealed the 5th November 1861, and dated the 14th May 1861.
PROVISIONAL SPECIFICATION left by the said William Clark at the
Office of the Commissioners of Patents, with his Petition, on the
14th May 1861.
I, WILLIAM CLARK, of 53, Chancery Lane, in the County of 'Middlesex,.
Engineer & Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF STEEL," to be as
follows:-
Steel consists of a carburet of azoted iron, and is produced by heating iron
with matters furnishing carbon and azote, but an impediment to its direct for-
mation in this manner consists in the presence of the metalloids which are
always contained in iron.
Now this Invention consists in transforming iron into steel by cementation
in a mixture of pulverized coal & carbonate of baryta, & heating the whole to
a bright redness. The reactions which take place are as follows:-The
hydrogen, disengaged by the coal, forms with the sulphur contained in the iron

page_text: sulphuretted hydrogen, which is absorbed by the carbonate of baryta. The
azote and the carbon then combine with the refined iron, and transform it into
steel. The azote employed in this reaction may be furnished, 1st, by the
coal, which disengages ammonia; 2ndly, by the air contained in the cementing
chamber or trough; 3rdly, by the decomposition of the cyanide of barium
which may be formed. The coal may be replaced by any other body furnishing
carbon, hydrogen, & azote when decomposed by heat. The carbonate of
baryta may be replaced by any other alkaline, carbonate, or substance capable
of absorbing sulphuretted hydrogen.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Clark in the Great Seal Patent Office on the
13th November 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
CLARK, of 53, Chancery Lane, in the County of Middlesex, Engineer and
Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of May, in the year of our
Lord One thousand eight hundred and sixty-one, in the twenty-fourth year of
Her reign, did, for Herself, Iler heirs and successors, give and grant unto
me, the said William Clark, Her special licence that I, the said William
Clark, my executors, administrators, and assigns, or such others as I, the
said William 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, use, exercise, and vend, within the United Kingdom of Great Bri-
tain and Ireland, the Channel Islands, and Isle of Man, an Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF STEEL," a communication from
abroad by Messrs. Louis Joseph Frédéric Margueritte & Alfred Lalouël de
Sourdeval, both of 29, Boulevart St. Martin, Paris, in the Empire of France,
upon the condition (amongst others) that I, the said William 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.

page_text: NOW KNOW YE, that I, the said William 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) :-
The many theories in existance with reference to the manufacture of steel,
and the difficulty of determining its exact composition, and of deciding on the
elements indispensable for its formation, lead to the consideration whether
steel should necessarily contain azote and carbon, or carbon only. I prefer to
apply both these agents to the iron in a state the most favorable for their
assimilation. For this purpose I employ coal, which when calcined will
furnish ammonia and carbonated hydrogen. The azote in the ammonia and
the carbon in the hydro-carburets are thus combined in the iron, and penetrate
its pores when dilated by heat. This, however, will not be. sufficient to produce
steel, especially of good quality, as from recent researches it has been ascer-
tained that the purity of the iron is an essential condition for transforming it
into steel. Thus iron containing sulphur, phosphorus, or silicium, which are:
impurities, produce bad steel, if steel at all; as from the presence of these
metalloids the azote and the carbon cannot combine with the iron in the
proper proportions. Experience thus proves that to obtain steel of good
quality it is necessary to treat pure iron or iron capable of being purified. It
is above stated that the principal impurity in iron consists of sulphur. Hence
blast furnaces employing coke, which always contains sulphur, do not furnish
iron free from thus substance, and iron of all kinds contains more or less
of it.
As before mentioned, I have found that by the employment of hydrogen the
sulphur may be completely extracted from the iron; thus, if a bar of iron is
heated in a current of hydrogen gas, a great quantity of sulphuretted hydrogen
will be evolved, and in this manner almost the whole of the sulphur will be
extracted. This point established, it will be evident that any kind of iron
may be converted into steel after being purified by heating it in hydrogen or
hydrogeneous products.
For this purpose I employ coal, but this being itself sulphuretted it is
necessary to obtain a body which may not only retain the sulphur contained
in the coal, but also absorb the sulphuretted hydrogen by the iron in contact
with the bydrogeneous matters. To effect this I use carbonates of potash,
soda, or baryta; the latter by preference in all cases, owing to its infusibility
and low price.
The method of operating is as follows:--I prepare a mixture of carbonate
of baryta and finely pulverized coal in suitable proportions according to the

page_text: quality of the coal, and place it in a cementing chamber or in crucibles, gas
retorts, furnaces, or other apparatus. The bars of iron are placed in the
ordinary way in this mixture, and the whole heated to a bright red heat for a
certain time according to the size of the iron under treatment. After this
calcination, when separated from the coke, the metal presents, when broken,
the grain and hardness of steel after tempering, and, in fact, possesses all the
qualities of the best steel. Thus coal furnishes the best purifying agent for
the iron, the hydrogen, which produces the conversion, preparing it for the
action of the azote and the carbon. Other hydrogeneous matters may be sub-
stituted for the coal, such as ammonia, for instance, which would exert great
influence in the process of conversion. A current of ammoniacal gas acting
on iron heated to redness will disengage considerable quantities of sul-
phuretted bydrogen. Mineral and vegetable combustible matters may also be
employed in lieu of the coal, but with less advantage, as none of them contain
a large amount of azote. The refinery of the iron may be effected before or
simultaneously with the process of conversion.
The azote is obtained either by the formation of cyanide of barium or from
the atmospheric air circulating in the mixture; or, lastly, by the decomposition
of the ammonia which is disengaged by the coal.
Having described the nature of this Invention, and the manner of performing
the same,. I declare that what I claim as the Invention to be protected by the
hercin-before in part recited Letters Patent is, the simultaneous purification
and conversion of iron by calcining it in the presence of coal or other hydro-
geneous or azoted matter in combination with a carbonate, alkali, or other
substance capable of absorbing sulphuretted hydrogen.
In witness whereof, I, the said William Clark, have hereunto set my
hand and seal, this Sixth day of November, in the year of our
Lord One thousand eight hundred and sixty-one.
Witness,
W. G. E. SWINNOCK,
53, Chancery Lane.
W. CLARK. (L.S.)