Improvements in the Manufacture or Production of Hollow Castings.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture or Production of Hollow Castings.
We, ROBERT ABBOTT HADFIELD, of The Grove, Endcliffe Vale Road, Sheffield,
in the County of York, Steel Manufacturer, and ALEXANDER GEORGE MACKENZIE
JACK, of Fir Vale House, Sheffield aforesaid, Steel Works Manager, do hereby
declare the nature of this invention to be as follows:-
When casting hollow articles in steel, specially those of cylindrical form, in
either metallic or sand moulds, the cores as heretofore usually made are liable to
give off gases which enter the fluid steel and cause unsoundness in the resulting
castings. This is particularly the case with castings having walls of unequal
thickness, such as projectiles the walls of which are considerably thicker at the
base than at the side. Now this invention has for object to obviate the dis-
advantage above referred to and also, by ensuring rapid cooling of the molten
steel, to prevent the settling that is liable to take place in the thick part of the
casting if it were allowed to cool slowly.
For this purpose we cast or otherwise secure around the exterior of the core body
or spindle a coating, bush or layer (hereinafter called the coating) of material, for
example lead or a fusible metallic alloy or composition, that will melt when or
after the molten steel surrounds it, but which will not give off gases liable to enter
the steel and cause unsoundness thereof. Such a coating takes the place of the
ordinary hemp, hayband, sand or other coating usually employed in the manu-
facture of cores for castings. The fluid steel, which is poured quickly in the usual
manner to form the required casting, rapidly envelopes that portion of the core
covered by the coating which does not melt, or only partially melts, before the steel
has surrounded and set on it. When, or it may be before, the contraction caused
by the cooling of the casting commences, the coating will melt and thus allow the
steel to contract freely without danger of cracking or otherwise injuring the
casting, and also admit of the core barrel being easily removed from the casting.
Dated this 28th day of January 1897.
Improvements in the Manufacture or Production of Hollow Castings.
We, ROBERT ABBOTT HADFIELD, The Grove, Endcliffe Vale Road, Sheffield, in
the County of York, Steel Manufacturer, and ALEXANDER GEORGE MACKENZIE JACK,
Price 8d.1

page_text: of Fir Vale House, Sheffield aforesaid, Steel Works Manager, do hereby declare
the nature of this invention and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
When casting hollow articles in steel, specially those of cylindrical form, in
either metallic or sand moulds, the cores as heretofore usually-made are liable to
give off gases which enter the fluid steel and cause unsoundness in the resulting
castings. This is particularly the case with castings having walls of unequal
thickness, such as projectiles the walls of which are considerably, thicker at the
base than at the side. Now this invention has for object to obviate the dis-
advantage above referred to and also, by ensuring rapid cooling of the molten
steel, to prevent the settling that is liable to take place in the thick part of the
casting if it were allowed to cool slowly.
For this purpose we cast or otherwise secure around the exterior of the core body
or spindle a coating, bush or layer (hereinafter called the coating) of material,
for example lead or a fusible metallic alloy or composition, that will melt when or
after the molten steel surrounds it but which will not give off gases liable to enter the
steel and cause unsoundness thereof. Such a coating takes the place of the ordinary
hemp, hayband, or other coating and sand or equivalent material usually employed
in the manufacture of cores for castings. The fluid steel, which is poured quickly
in the usual manner to form the required casting, rapidly envelopes that portion of
the core covered by the coating which does not melt, or only partially melts,
before the steel has surrounded and set on it. When, or it may be before,
the contraction caused by the cooling of the casting commences, the coating will
melt and thus allow the steel to contract freely without danger of cracking or
ctherwise injuring the casting, and also admit of the core barrel being easily
removed from the casting.
Fig. 1 of the accompanying drawings shews partly in longitudinal central
section and partly in elevation, one construction of core according to this invention
suitable for the manufacture of cast steel shells the walls of which are thicker at
the base than at the sides. A shell of this kind is shewn around the core. In this
case that part 1" of the hollow core spindle around which the thickened base
portion 2 of the shell 2 is to be formed, instead of being surrounded by a coating
of ordinary hemp, hay-band, or like material and sand or equivalent material as
heretofore, is according to this invention replaced by a coating or bush 3 of lead
or equivalent material which is applied, it may be by casting, around the said
portion 1 of the spindle 1, the remaining portion of the core body being formed
in the usual way, as for example of hemp or hav-band 4 and sand 5 applied around
the remaining portion of the core spindle which should be perforated as usual
whilst that part 1 of the spindle to which the fusible coating or bush 3 is applied
is unperforated. Upon molten steel being poured into a suitable mould A pro-
vided with a core such as described, it will quickly surround the metal coating or
bush 3 which will not melt or will only partially melt before the steel has sur-
rounded and set on it, but will afterwards melt to a sufficient extent to allow of
the steel contracting freely without danger of cracking or otherwise injuring
the casting and also to admit of the easy removal of the core spindle from such
casting.
When using an ordinary core spindle or barrel that is perforated along its whole
length, it should, as shewn in Fig. 2 be wrapped at the part 1° to be surrounded
by the lead or other fusible metal coating or bush with some suitable material 6,
such as asbestos or hemp thinly coated with sand, that will prevent the lead coat-
ing or bush when melted from entering the hollow core spindle 1 and choking the
vent.
As will be obvious the extent of the core body or spindle provided with a
fusible metal coating as described will vary with the shape and dimensions of the
object it is desired to cast. For instance, the lead coating may in some cases
extend upward for a distance above the thick base part of the shell, as indicated
in dotted lines at 3" in Fig. 1, but it will generally be found sufficient to coat only

page_text: that part 1 of the core body or spindle that passes through the base or thickest
portion of the shell or equivalent body to be cast.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed we declare that what
we claim is:-
1. In the manufacture or production of hollow castings the use of a core body or
spindle having a coating, bush or layer of material that will melt when or after
the molten metal of which the casting is to be made surrounds it but which will
not give off gases liable to enter the said metal and cause unsoundness thereof,
substantially as herein described.
2. In the manufacture of hollow castings the use of cores constructed sub-
stantially as described and shown.