AN IMPROVEMENT IN A communication from MOULDS AND CORES FOR USE IN CASTING STEEL
Year: 1879

page_text: LETTERS PATENT to Alexander Melville Clark, of Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "AN IMPROVEMENT IN
A communication from
MOULDS AND CORES FOR USE IN CASTING STEEL."
abroad by George Cowing, of Cleveland, in the County of Cuyahoga, State of
Ohio, United States of America.
Sealed the 28th March 1879, and dated the 4th February 1879.
a
COMPLETE SPECIFICATION filed by the said Alexander Melville Clark
the Office of the Commissioners of Patents on the 4th February 1879.
ALEXANDER MELVILLE CLARK, of Chancery Lane, in the County of Middlesex,
Patent Agent. "AN IMPROVEMENT IN MOULDS AND CORES FOR USE IN CASTINGT
STEEL." A communication from abroad by George Cowing, of Cleveland, in the
County of Cuyahoga, State of Ohio, United States of America.
This Invention relates to moulds and cores for use in casting steel, and especially
steel made by the open hearth furnace, from which the steel comes very much
hotter than when melted by any other known process. It is on account of this
intense heat of the molten steel that difficulties have arisen in casting, as the
contact of the steel with the walls of the mould fuses the material of the mould and
This effect
forms a flux or scoria that coats the casting and is difficult to remove.
takes place with all materials that have been heretofore used for moulds. Common
sand, plumbago, charcoal, coke, and other materials have been used for moulds, but
the foreign matters contained in these substances are of such a nature that the
successful prevention of flux or scoria has not been heretofore accomplished. The
object of this Invention is to construct a mould from a substance that is adapted
for ordinary use as moulding material and possesses refractory qualities sufficient
to successfully resist the tendency to flux when brought in contact with the hottest
molten steel.
According to this Invention, silica is used in the construction of moulds for this
purpose, as it has been discovered that pure silica with suitable binding material
answers the requirements set forth, and that by its use steel castings may be
In proportion as the
produced almost or entirely free from the flux or scoria.
silica used for moulds contains limestone, feldspar, mica, or other silicates, oxide of
iron, or foreign matters of any kind, the castings will be coated as described, and
sand, such as is used for moulds, contains silica more or less mingled with the
substances named. This fact without doubt explains the reason why it has been
heretofore considered impracticable to use sand moulds or moulds made from

page_text: furnace.
In carrying out this Invention it is preferred to obtain the silica from rock
crystal, white pebbles, or white sand; if white pebbles are used they should first
be pulverised and thoroughly freed from oxide of iron or other foreign matters.
When about to be formed into moulds the silica is to be mixed with any appropriate
binding material; such as molasses, sour beer, flour, or other glutinous substance,
silicate of alumina, or the like, care being taken to employ no substance containing
any metallic oxide or anything that might flux. A sufficient quantity of the
binding material will be mixed with the pulverised silica to form a plastic mass
that can be moulded and will retain its shape after moulding.
An additional advantage obtained by the application of this Invention is the
ability to cast mild steel, i.e; steel having a low per-centage of carbon, which cannot
be done in moulds consisting of or containing plumbago, graphite, coke, or other
forms of carbon without subsequent annealing. As stated before, I am aware that
materials containing more or less silica have been used for moulds, but in such
materials the refractory qualities of silica which render it useful for the purpose are
neutralised by the other materials.
Having described the nature of the Invention, and the manner of performing the
same, I declare that what I claim as new and desire to secure by Letters Patent
is,-
A mould or core composed of or constructed from a mass consisting of silica and
a suitable binding material, substantially as and for the purposes specified.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Third day of February, in the year of our Lord One
thousand eight hundred and seventy-nine.
A. M. CLARK. (L.S.)