IMPROVE- MENTS IN THE PRODUCTION OF CAST STEEL OR INGOT IRON, AND IN THE MOULDS EMPLOYED FOR THAT PURPOSE
Year: 1881

page_text: LETTERS PATENT to Charles William Siemens, of No. 12, Queen Anne's Gate,
Westminster, in the County of Middlesex, for an Invention of "IMPROVE-
MENTS IN THE PRODUCTION OF CAST STEEL OR INGOT IRON, AND IN
THE MOULDS EMPLOYED FOR THAT PURPOSE."
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents on the 1st March 1881.
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex. "IMPROVEMENTS IN THE PRODUCTION OF CAST STEEL OR
INGOT IRON, AND IN THE MOULDS EMPLOYED FOR THAT PURPOSE."
Steel produced by the Bessemer or open hearth (Siemens) process is usually
poured when in the fluid condition into massive moulds of cast iron of square or
rectangular section slightly rounded at the corners. When an ingot produced in this
manner is broken across its major axis a want of homogenity is observable, which
is particularly striking if the steel is low in carbon, or what is called mild steel or
ingot iron. All round the outer surface the metal presents the appearance of being
honey-combed or divided by innumerable oblong cavities projecting from the surface
inward to the depth of about an inch. When these ingots are reheated ferric oxide
enters these cavities to some extent, and when subsequently hammered or rolled
the bars or plates produced are liable to show surface defects, the result of imperfect
homogenity.
According to my present invention I produce ingots of mild steel or ingot iron,
in which these surface defects are avoided, by casting the metal in ingot moulds
made of such a form and material as to enable these, while affording the necessary
strength, to be made of greatly reduced thickness, and at the same time to offer a
minimum amount of surface in contact with the metal, by which means the
chilling action of the mould upon the metal, which gives rise to the honey-
combed crust above referred to, is avoided or greatly reduced. For this purpose
I construct the ingot moulds circular in transverse section, and I make them by
preference of cast steel or wrought iron or steel, so that both form and material
[Price 1

page_text: enable me to reduce the thickness of wall to, say, one third of the usual thickness,
and the surface in contact with the fluid steel being at the same time reduced to a
minimum, owing to the circular form, it follows that the metal composing the
improved mould is heated through and through before the fluid metal near the
surface is reduced to a pasty condition by cooling, so that the whole of the metal
sets gradually into a solid block within the heated mould. The metal composing
the mould is heated moreover more uniformly, and is therefore much less liable to
cracking through unequal expansion, as is the case with the ordinary heavy mould
of rectangular section. The resulting ingots of circular section when put into the
reheating furnace present the further advantage of receiving the heat of the flame
more uniformly, presenting only a line of contact with the bottom of the furnace,
and there are no corners or edges such as exist in ordinary ingots which are subject
to an excessive action of the flame; these ingots also admit of being turned round
on the furnace bed by a comparatively slight effort in simply rolling them. In
passing the ingots of circular section through the rolls, or in hammering them into
squares or flats, a further advantage results from this form, namely, that the
pressure being confined to a smaller surface effects the consolidation of the middle
of the ingot more thoroughly, and increases the flow of metal consequent upon a
thorough change of form.
Instead of stoppering these improved ingot moulds in the usual manner by means
of sand, plate, and wedges, I bring pressure to bear upon the upper surface of the
metal in a manner more completely under control by providing each ingot mould
with two or more horns projecting from opposite points in a circular and inclined
direction, and I also provide a circular plate having two radial extension rods
pivotted to its upper surface. When the mould is filled to a sufficient height with
fluid steel, sand or mould is added until it is completely filled. Excessive sand is
struck off, the plate is put on, and its radial arms are moved round underneath the
said horns until their motion is forcibly arrested by pressing against the undersides
of the horns, by which means the plate is pressed downward upon the sand or
loam covering the fluid steel, which is thus prevented from rising. In order to
prevent the rising of the ingot mould itself, the horns are by preference formed on
separate bars or rods that are continued downwards along the outer surface of the
mould and are fastened to the foundation plate by means of wedges or otherwise.
The same mould is applicable for being filled from the bottom, but in order to
limit the extent to which the steel shall be allowed to rise a round disc is intro-
duced from below and held up by means of a central rod fastened to a cross bar by
which it is held up and tightened against the helical surfaces presented by the
upper sides of the horns above referred to. If after filling the mould with open
top with fluid metal it is desired to apply a pressure superior to that which may
be afforded by the means above described, the pressure of steam may be resorted
to. The plate attached to the cross bar is provided in that case with a rim
projecting downward, which is turned slightly conical, fitting the interior of the
mould, which is bored at its upper extremity. Into the hollow of this circular
cover a shallow receptacle open at its upper extremity, is fitted (which may be
made of sheet iron), and being filled with water beforehand, a measured quantity of
that fluid is included within the mould in putting on the cover and fastening it
The heat of the
by turning its radial rods against the under sides of the horns.
fluid metal will soon cause the water to boil, and the pressure thus created will
effect its compression. A safety valve is provided in the cover however to limit the
pressure thus accumulating.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Charles William Siemens in the Great Seal Patent Office on
the 29th August 1881.
CHARLES WILLIAM SIEMENS, of No. 12, Queen Anne's Gate, Westminster, in the
County of Middlesex. "IMPROVEMENTS IN THE PRODUCTION OF CAST STEEL OR
INGOT IRON, AND IN THE MOULDS EMPLOYED FOR THAT PURPOSE."
"
"
or
Steel produced by the Bessemer or the open hearth (Siemens) process is usually
poured when in the fluid condition into massive moulds of cast iron of square or
rectangular section slightly rounded at the corners. When an ingot produced in
this manner is broken across, a want of homogeneity is observable, which is
particularly striking if the steel is low in carbon, or what is called "mild steel'
ingot iron."
All round the outer surface the metal presents the appearance of
being honey-combed or divided by innumerable oblong cavities extending from the
surface inwards to the depth of about an inch. When these ingots are reheated
iron oxide enters these cavities to some extent, and when they are subsequently
hammered or rolled the bars or plates produced are liable to shew surface defects,
the result of imperfect homogeneity.
According to my present Invention I produce ingots of mild steel or ingot iron,
in which these surface defects are avoided, by casting the metal in moulds of such
a form and material as to enable these, while affording the necessary strength, to
be made of greatly reduced thickness, and at the same time to offer a minimum
amount of surface in contact with the metal, by which means the chilling action
of the mould upon the metal which gives rise to the honey-combed crust above
referred to is avoided or greatly reduced. For this purpose I construct the ingot
moulds circular in transverse section, and I make them by preference of cast steel
or wrought iron or steel, so that both form and material enable me to reduce the
thickness of wall to, say, one third of the usual thickness, and the surface in
contact with the molten metal being at the same time reduced to a minimum
owing to the circular form, it follows that the metal composing the improved mould
is heated through and through before the fluid metal near the surface is reduced to
a pasty condition by cooling, so that the whole of the metal sets gradually into a
solid block within the heated mould. The metal of the mould is moreover heated
more uniformly, and is therefore much less liable to cracking through unequal
expansion than is the case with the ordinary heavy mould of rectangular section.
The resulting ingots of circular section when put into the reheating furnace present
further the advantage of receiving the heat of the flame more uniformly, presenting
only a line of contact with the furnace bed, and there are no corners or edges such.
as exist in ordinary ingots which are subject to an excessive action of the flame;
these ingots also admit of being turned round on the furnace bed by a compara-
tively slight effort in simply rolling them.
In passing the ingots of circular section through the rolls, also in hammering
them into squares and flats, a farther advantage results from this form, namely,
that the pressure being confined to a smaller surface effects the consolidation of the
middle of the ingot more thoroughly, and increases the flow of metal consequent
upon a thorough change of form. Moulds of circular form have sometimes been
used for producing shafts or other round articles so as to avoid change of form in
working up and finishing such articles. It will be understood however that such
use of circular moulds forms no part of my present Invention.
Instead of stoppering these improved ingot moulds in the usual manner by
means of sand, plate, and wedges, I bring pressure to bear upon the upper surface
of the metal, in a manner more completely under control by providing each ingot
mould with two or more horns projecting from opposite points in a circular and
inclined direction, and I also provide a circular plate having two radial extension

page_text: rods pivotted to its upper surface. When the mould is filled to a sufficient height
with fluid metal, sand or loam is added till it is completely filled. Excessive sand
is struck off, the plate is put on, and its radial arms are moved round underneath
the said horns pressing against their undersides, by which means the plate is
pressed downwards upon the sand or loam covering the fluid metal, which is thus
prevented from rising. When the mould is not itself held down to the foundation
the horns may be formed on separate bars extended down and secured to the
foundation so as to prevent the mould from rising.
This mould may be filled from the bottom, but to limit the extent to which the
metal shall be allowed to rise in it a round disc is held at the required height by a
central rod attached to a crosshead at the top of the mould.
If after filling the mould it is desired to apply additional pressure the pressure
of steam may be resorted to. For this purpose, according to my Invention, the
plate attached to the cross bar is provided with a rim projecting downwards, which
is made slightly conical, fitting the interior of the mould at its upper extremity.
Into the hollow of this circular cover a shallow receptacle open at the top, which
may be of sheet iron, is fitted, and being charged with water beforehand a measured
quantity of that fluid is included within the mould in putting on the cover, and
fastening it by turning its radial arms under the horns. The heat of the fluid
metal will soon cause the water to boil, and the pressure thus created will effect
compression of the metal. A safety valve is provided in the cover to limit the
pressure thus accumulating.
In the accompanying Drawing Fig. 1 shews an elevation partly in vertical
section and Fig. 2 a plan of a set of the improved ingot moulds supplied one from
the top and the others from below, and Fig. 3 is a transverse section of one of the
latter. Each mould has a tapering swell at its lower end, and dogs, which may be
secured by bolts, as shewn at A, or by keys, as shewn at B, bearing against the
taper of the mould and holding it firmly down to the foundation or bed C, in which
is formed the supply runner D. The stopper of the mould may be pressed down
by a screw, as shewn at E, or it may be fixed by a cross key driven through lugs
of the mould, as shewn at F.
Figs. 4 and 5 are vertical sections at right angles to each other of a mould made
with projecting horns G having their under faces somewhat inclined. The mould
`stopper has hinged to it a crosshead H the radial arms of which extend under the
'horns G. On turning this crosshead by a bar I inserted into a hole of the cross-
head its radial arms bearing along the under face of the horns G have a screw like
action in pressing down the stopper.
Fig. 6 is a section of the upper part of a mould and its cover with means of
providing steam pressure to compress the metal in the mould. The cover K has a
downwardly projecting lip k which fits the mouth of the mould. To the cover is
attached a sheet iron vessel M which can be charged with the required measure of
water. The cover being fixed as shewn in Figs. 4 and 5 or otherwise, the heat of
the metal in the mould converts the water in the vessel M into steam which
subjects the metal in the mould to pressure; N is a safety valve loaded by a spring
adjustable by a screw cap to such pressure as may be suited to the strength of the
mould.
In witness whereof, I, the said Charles William Siemens, have hereunto set
my hand and seal this Third day of August. in the year of our Lord One