IMPROVEMENTS IN CORES FOR CASTING STEEL AND OTHER METALS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Henry Arthur Gadsden at the Offico
of the Commissioners of Patents on the 7th August 1883. A communication
from James Amory Herrick, a person resident at New York, in the United
States of America)
HENRY ARTHUR GADSDEN, of 19 Australian Avenuo, in the City of London,
"IMPROVEMENTS IN CORES FOR CASTING STEEL AND OTHER METALS "
(a commu-
nication from James Amory Herrick, a person resident at New York, in the
United States of America)
This invention relates to improvements in cores used for casting steel and other
metals and particularly to that class of cores known as ventilated cores of which
the following is a specification, reference being had to the accompanying drawings
similar letters indicating similar parts throughout the series.
Fig 1. is a vertical section of a core, constructed according to this invention,
together with one form of a mould, and a plate or base upon which the mould is
placed.
Fig. 2. is a horizontal section of the core and mould, and a plan view of tho
plate.
Fig. 3 is a vertical section of the perforated centre piece, shewing the same more
in detail.
•
In Figs. 1 and 2 A is an ordinary cast iron mould in which the core is placed,
though it is obvious any suitable mould may be used, E is a plate upon which the
mould rests. B is a coating of pure or nearly pure silica mixed with any suitablo
glutinous or adhesive material, such as glue water, sour beer, or other similar
substance, used as a binder. C is a rope of hay, straw or other like material
wound about a perforated centre piece D, which in turn is fastened to the plate E,
by a bolt F, though any convenient means may be used. Holes are left at top and
bottom of centre piece, for free passage of air and gases. This is made by
preference of wrought iron pipe, perforated at proper intervals, and fitting into a
socket in plate E
In making large cores by this improved process I prefer to wind hay, straw or
other similar material around the core iron or centre pieco and the silica mixture is
applied to the same in the ordinary manner well known to the art. The thickness
D

page_text: of the coating of the silica mixture is proportioned to the weight of the casting or
size of the core.
In case of small cores I prefer to omit the above described winding of hay,
straw etcetera, and to apply the coating of silica directly to the perforated contre
piece. The drawing shown represents a single mould, into which the metal is
poured from the top, but moulds may be set in groups and metal poured from the
bottom. When so constructed, and used, I prefer to conduct the fluid metal in fire
proof ducts under and across the mould in such a way as to cause a circular
motion of the metal around the core, by which means the gases are thrown into
the core and escape; the slag rises along the core, and is found at top of casting
leaving body of metal sound and free from defects: My foreign correspondent has
found in casting steel, and particularly that variety known as open hearth steel,
that the ordinary form of core is useless and fails to stand the intense cutting
action of the fluid steel or metal. Such a core is made of sharp sand, moulding.
loam, a mixture of loam clay etcetera applied to either a solid or ventilated centre
piece and coated with plumbago, gas carbon, ground bricks, ganister, or other
material known to the trade or art.
This thin coating is destroyed by the fluid steel, giving off gas to the resulting
castings, and forming blowholes in the steel. A more or less thick lining of scoria
or slag is thus formed upon the interior surface of resulting castings, and rendering
same useless for subsequent operations.
The silica on the contrary is impervious to the metal, but pervious to the gases.
contained in the same. I prefer to obtain my silica from quartz, pebbles or quartz
_rock_ground to a sufficient fineness, or from white sharp_quartz sand, though any
form of pure or nearly pure silica will serve.
This is mixed with glue water, sour beer, rye meal, or any similar glutinous
substance as a binder, to keep the silica in proper form and shape.
_ .A.simple.form-of mould-and-core-is shewn for convenience but any shape or
form of the improved core can be used in connection with any suitable mould.
I am aware that cores of solid silica have been used, but
any such core will fail,
on account of heat not being able to escape through the body of core itself and
all gases are left as blowholes in resulting castings.
I ain also aware that a ventilated centre piece is not new to the art, but a
combination of the two, silica and a ventilated centre piece is new and such a coro
is only device which will withstand cutting action of open hearth steels and enable
the heated gases to escape