IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL
Year: 1856

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street, in
the City of London, Patent Agent, for the Invention of "IMPROVEMENTS
IN THE MANUFACTURE OF CAST STEEL."-A communication.
Scaled the 22nd July 1856, and dated the 12th February 1856.
PROVISIONAL SPECIFICATION left by the said Richard Archibald
Brooman at the Office of the Commissioners of Patents, with his Petition,
on the 12th February 1856.
I, RICHARD ARCHIBALD BROOMAM, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL," (communicated to me by
a foreigner residing abroad,) to be as follows:-
This Invention consists in improvements in the manufacture of. cast steel,
whereby the conversion of wrought iron into cast steel is effected without first
having recourse to the process of cementation, and the following characteristics
are imparted to the steel-Firstly, capability to be welded at a common
forge without employing borax or other similar salt; secondly, great ductility
and tenacity, whereby it may be heated to a high degree, and then hammered
without flying to pieces, and the steel may be made of various degrees of
hardness without impairing its welding property or capability of being worked
under any temperature. The improvements consist in mixing sal ammoniac
and prussiate of potash in the melting pot or crucible along with the pieces

page_text: of wrought iron, whereby the said ingredients become incorporated with the
iron, and not only effect the complete conversion of it into steel, but also
impart to it the before mentioned qualities. The malleable and welding
quality is imparted by the incorporation of sal ammoniac, and the conversion
is effected by prussiate of potash. The process may be conveniently per-
formed in crucibles arranged in furnaces of the construction usually employed
in the manufacture of cast steel from blister steel. Into a crucible of that
description the wrought iron to be .converted is put, having been cut into
small pieces, and the above-mentioned ingredients are added; I find the fol-
lowing proportions answer the purpose: to each ton of iron, 2 lbs. sal
ammoniac and 1 lb. prussiate of potash. The top must be kept covered with
some material to form scoria to keep the contents excluded from air; red
brick dust, furnace slag, or a little oxide of manganese will answer the
purpose. The whole must be raised to a heat which will melt the mass, and
this heat is to be maintained for several hours, say, three or thereabouts, when
the process will be complete, and the inetal may be poured off into moulds.
It may afterwards be tilted into bars in the usual manner. The hardness is
regulated or determined by the proportion of prussiate of potash employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Archibald Brooman in the Great Seal Patent Office
on the 12th August 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twelfth day of February, in the year of our Lord
One thousand eight hundred and fifty-six, in the nineteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Richard Archibald Brooman, Her special licence that I, the said Richard
Archibald Brooman, my executors, administrators, and assigns, or such others
as I, the said Richard Archibald Brooman, 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 MANUFACTURE: OF CAST: STEEL," (communicated to me by

page_text: a foreigner residing abroad,) upon the condition (amongst others) that I, the
said Richard Archibald Brooman, 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 Richard Archibald Brooman, 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 thereof (that is to say):-
This Invention is for effecting the immediate conversion of bar or malleable
iron into cast steel by the single operation of melting, which operation inay
be performed in a few hours. Almost any description of iron, however poor,
may by this Invention be converted into genuine steel, having also the fol-
lowing peculiar qualities, great tenacity and malleability, as well as capability
to be welded, and capability to stand high degrees of heat, (without much, if
any, deterioration) and repeated heatings. It may therefore be easily wrought
in the various ways desirable for working steel. The basis of the Invention
consists in the introduction into melting pots or crucibles of the usual descrip-
tion for melting blister steel along with the pieces of wrought or malleable
iron of certain chemicals in which the principle cyanogen shall be contained.
As, for example, cyanide of potassium, ferrocyanide of potassium, &c., also to
be used in connection with some form of sal ammoniac. It has been found
that the malleability is greatly to be ascribed to the use of this last-named salt.
The
process is as follows:-For the purpose of a continuous manufacture,
the usual furnaces and melting pots suitable for melting blister steel may be
employed. I prepare the malleable iron (which may be of any description,
such as bar, scrap, blooms, &c.) by cutting or breaking it up into small
pieces. In a fifty pounds charge of iron in a crucible I introduce ten ounces
of charcoal, six ounces of common table salt, half an ounce of brick dust or
oxide of manganese, one ounce of sal ammoniac, half an ounce of ferro-
cyanide of potassium. The pot is then to be covered and introduced into the
furnace and the contents thoroughly melted, the heat being maintained for
the space of three hours or thereabouts. The mass is then to be poured off
into iron moulds in the ordinary way of pouring cast steel, and with the
usual care required for producing a solid ingot. This may then be rolled
into sheets, or hammered and tilted into bars, after the common method. In
the above-described process the employment of table salt, manganese, or brick

page_text: dust is for the formation of scoriæ upon the top of the melted mass, the better
to keep out the air.
The proportions of ingredients above given may be varied, and some may be
omitted altogether, or others substituted. The essentials are the sal ammoniac,
some matter affording cyanogen, and charcoal. Fine cast steel may be
produced with ferro-cyanide of potassium and charcoal, or ferrid-cyanide of
potassium instead of the ferro-cyanide, also with sal ammoniac and charcoal.
The hardness or brittleness as well as fineness of grain and degree of malle-
ability may be varied by varying the proportions of the several ingredients,
especially of the charcoal, sal ammoniac, and cyanogen. No particular
character or quality of iron is necessary. Steel can be produced by this process
from common English iron equally as well as from the best Swedish.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I claim the employment
of cyanogen (in any of its forms or compounds, especially those from which it
is most readily obtained, as, for instance, ferro-cyanide of potassium,) and of
sal ammoniac, either separately, or in combination with each other, or with
charcoal or other ingredients, for converting wrought iron into steel.
In witness whereof, I, the said Richard Archibald Brooman, have here-
unto set my hand and seal, this Eleventh day of August, One thousand
eight hundred and fifty-six.