IMPROVEMENTS IN THE CEMENTATION OR CONVERSION INTO STEEL OF WROUGHT IRON OR ARTICLES FIRST MADE THEREOF
Year: 1871

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Patent Agents, Southampton Buildings, London, for
the Invention of "IMPROVEMENTS IN THE CEMENTATION OR CONVERSION
INTO STEEL OF WROUGHT IRON OR ARTICLES FIRST MADE THEREOF." -A
communication from abroad by Louis La Brèche-Viger, of Montreal,
Canada, Advocate.
caled the 7th May 1872, and dated the 30th November 1871.
PROVISIONAL SPECIFICATION left by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition, on
the 30th November 1871.
65
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co.,
Patent Agents, Southampton Buildings, London, do hereby declare the
nature of the said Invention for IMPROVEMENTS IN THE CEMENTATION OR
CONVERSION INTO STEEL OF WROUGHT IRON OR ARTICLES FIRST MADE THEREOF," to
be as follows:-
This Invention relates to the manufacture of axes, chisels, hammers,
saws, augers, and other tools and instruments which are usually made of

page_text: steel or of malleable iron, or partly of both by welding, and also to the
manufacture of rails, axles, and parts of machinery where steel may be
substituted for malleable iron, or may be usefully combined with
malleable iron by welding.
The articles to be treated are made of and with wrought iron
first without however finishing them completely, and then converted
wholly or partly into steel by immersing them in a bath of molten
cast iron free from sulphur or phosphorus and carbonized to its
utmost capacity. The best cast iron for this purpose is spiegl eisen, but
in default thereof such cast iron may be made by melting good
malleable iron or blister steel in a cupola furnace with the purest fuel
available, that is as free from sulphur as possible.
The articles are left in this bath a space of time which must vary with
the degree of hardness desired to be imparted to the metal and with the
size of the articles, and also according to the intention of converting the
whole mass into steel or of converting simply the surface so as to retain
a core of malleable iron.
Crucibles may be used for treating small objects, but for larger articles
or when large quantities are to be converted the ordinary reverberatory
furnaces may be used, the bottom of which I build with silicious sand.
After a number of operations with the same bath the cast iron would
not be rich enough in carbon, and consequently the heat required to
maintain it in a molten condition would be too high, which circumstance
might cause the fusion of the parts sufficiently carburized before the
underlying layers had attained the proper degree of conversion; to
obviate this difficulty I line the crucibles and the bottom of the furnaces
with a brasque of charcoal powder or of plumbago, into which I may
incorporate nitrogenous matters such as cyanides, or animal matters as
leather or horn pulverized, and also black oxide of manganese. This
brasque is intended to restore to the bath of cast iron the carbon which
may be abstracted from it by the metal during cementation, and to
supply the manganese and nitrogen which may be useful to the steel,
but it is not indispensable to the process.
The bath of cast iron may be renewed after each operation by using
fresh cast iron, or by remelting and recarburizing the same in a cupola
furnace in contact with fuel as pure as possible, and running it directly
from the cupola into the converting furnace over the objects to be

page_text: cemented. The converting bath may also be covered during the opera-
tion with a glass or slag covering to prevent the loss of carbon by contact
with the gas of the furnace.
After remaining in the converting bath the time required for the
degree of conversion sought for, the converted articles are taken out, or
better still the cast iron is tapped and run off, and the heat in the
furnace increased to free the objects from any portion of cast iron which
might adhere to them, when it will be found that they are, according as
the operation has been conducted, partly or totally converted into steel,
the quality of which will depend upon that of the iron used. The articles
are then finished by rolling or hammering.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 29th May 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of November, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William Robert Lake, Her special licence
that I, the said William Robert Lake, my executors, administrators,
and assigns, or such others as I, the said William Robert Lake, 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 CEMENTATION OR CONVERSION INTO STEEL OF WROUGHT IRON OR ARTICLES
FIRST MADE THEREOF,' a communication to me from abroad by Louis
La Brèche-Viger, of Montreal, Canada, Advocate, upon the condition
(amongst others) that I, the said William Robert Lake, my executors
or administrators, by an instrument in writing under my, or their,
"

page_text: 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 William Robert Lake, 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 :-
This Invention relates to the manufacture of axes, chisels, hammers,
saws, augers, and other tools and instruments which are usually made of
steel or of malleable iron, or partly of both by welding, and also to the
manufacture of rails, axles, and parts of machinery where steel may be
substituted for malleable iron, or may be usefully combined with
malleable iron by welding.
The articles to be treated are made of and with wrought iron first,
without however finishing them completely, and then converted wholly
or partially into steel by immersing them in a bath of molten cast iron
free from sulphur or phosphorous and carburized to its utmost capacity.
The best cast iron for this purpose is spiegel eisen, but in default thereof
such cast iron may be made by melting good malleable iron or blister
steel in a cupola furnace with the purest fuel available, that is as free
from sulphur as possible.
The articles are left in this bath a space of time which must vary with
the degree of hardness desired to be imparted to the metal and with the
size of the articles, and also according to the intention of converting the
whole mass into steel or of converting simply the surface so as to retain
a core of malleable iron.
Crucibles may be used for treating small objects, but for larger
articles or when large quantities are to be converted, the ordinary
reverberatory furnaces may be used, the bottom of which I build with
silicious sand.
After a number of operations with the same bath the cast iron would
not be rich enough in carbon, and consequently the heat required to
maintain it in a molten condition would be too high, which circum-
stance might cause the fusion of the parts sufficiently carburized before

page_text: the underlying layers had attained the proper degree of conversion.
To obviate this difficulty I line the crucibles and the bottom of the
furnaces with a brasque of charcoal powder or of plumbago, with which
I may incorporate nitrogenous matters such as cyanides, or animal
6 matters, as leather or horn pulverized, and also black oxide of man-
ganese. This brasque is intended to restore to the bath of cast iron
the carbon which may be abstracted from it by the metal during
cementation, and to supply the manganese and nitrogen which may
be useful to the steel, but it is not indispensable to the process.
The bath of cast iron may be renewed after each operation by using
fresh cast iron, or by remelting and recarburizing the same in a cupola
furnace in contact with fuel as pure as possible and running it directly
from the cupola into the converting furnace over the objects to be
cemented. The converting bath may also be covered during the operation
with a glass or slag covering to prevent the loss of carbon by contact
with the gas of the furnace.
After remaining in the converting bath the time required for the
degree of conversion sought for, the converted articles are taken out,
or better still the cast iron is tapped and run off, and the heat in the
furnace increased to free the objects from any portion of cast iron
which might adhere to them, when it will be found that they are,
according as the operation has been conducted, partly or totally con-
verted into steel, the quality of which will depend upon that of the
iron used. The articles are then finished by rolling or hammering.
Having thus fully described the said Invention as communicated to.
me by my foreign correspondent, I wish it understood that I do not
claim the principle of cementing malleable iron by immersion in molten
cast iron, as this was to a certain extent practised anciently upon lumps
of wrought iron; but I claim,-
First. The cementation or conversion into steel of articles made of
wrought iron by immersing them in a bath of molten cast iron after
they have been totally or partially worked into their respective shapes,
whereby the heaviest part of the work or the whole of it is accomplished
upon wrought iron and not upon steel, and the operation of welding
steel upon iron is dispensed with.
Second. The cementation or conversion into steel of articles made of
wrought iron by immersing them in a bath of cast iron in fusion in such

page_text: a way as to convert only the surface of such articles to the required
depth, leaving the interior in its original state of malleable iron, thereby
producing articles externally as hard as those made of pure steel, with
the toughness dependant upon that part of their substance retaining the
nature of malleable iron, and free from the inconvenience of imperfect
welding.
Third. The use of furnaces to effect such conversion on a large
scale.
Fourth. Lining crucibles or furnaces with a brasque of pure carbo-
naceous matter and nitrogenous substance, and oxide of manganese to
keep the bath of cast iron to 'its normal degree of carburization and to
supply nitrogen and manganese to the steel.
Fifth. Composing the bath of pure cast iron necessary for such con-
version by melting wrought iron or blister steel in a cupola furnace with
pure fuel and recarburizing the bath by returning the cast iron to the
said cupola furnace whenever required, the whole as above described and
for the purposes set forth.
In witness whereof, I, the said William Robert Lake, have hereunto
set my hand and seal, this Twenty-ninth day of May, in the year
of our Lord One thousand eight hundred and seventy-two.
Witness,
W. J. LOWE.
W. ROBT. LAKE. (L.S.)