Year: 1898

page_text: Date of Application, 12th Feb., 1898
Complete Specification Left. 8th Dec.. 1898-Accepted, 11th Mar., 1899
I, ROBERT ABBOTT HADFIELD, of Hecla Works, Sheffield, in the County of
York, Steel Manufacturer, do hereby declare the nature of this invention to be
as follows;-
-
My invention has for object the manufacture, in an economical manner, of steel
armour-piercing projectiles of an efficient kind produced by casting, or it may
be partly by casting and partly by forging (see the Specification of my Patent
No. 3237/92).
Of any suitable alloy I cast a hollow projectile, of any desired form, in a mould
of appropriate construction.
In the manufacture of hardened shells in the manner hereinafter described I
sometimes cast the shells in moulds point downward and, in order to prevent
settling or falling away from the core, I use a core formed of sand or composition
but having at its point a cast iron, steel or other metal tip which chills or sets
the steel forming the adjacent portion of the shell more quickly. By this means
a projectile is obtained practically free from settling or shrinkage cavities, thereby
considerably reducing the risk of cracks resulting from the hardening process.
The construction of the mould employed is varied according to the shell to be
produced. Thus if the head of the shell is to be thick and the walls thin, the
head portion of the mould is made of iron so as to rapidly chill the steel therein,
whilst the body portion is of sand so that the wall part of the sheel remains
If the walls and head are to
fluid and feeds metal to the head part as it sets.
be of fairly uniform thickness the shell may be cast entirely in an iron mould
or chill.
If the projectile is to have a forged point, or forged point and shoulder, I produce
it after the manner described in the Specification of my former Patent No. 3257/92,
already mentioned.
I effect the hardening of the projectile as I will now proceed to explain with
reference to Figs. 1 to 7 inclusive of the accompanying illustrative drawings,
premising that, as will be evident, the details are susceptible of modification
according to requirement.
Fig. 1 shows a tempering furnace in front elevation.
Fig. 2 shows a plan of the furnace.
Fig. 3 shows a horizontal section through line A A of Fig. 4.
Fig. 4 shows a vertical section through line B B of Fig. 3.
Fig. 5 shows a vertical section through line C C of Fig. 2.
Figs. 6 and 7 show, to a larger scale, vertical sections in planes at right angles
to one another of a shell with its point in a pot, and with internal liquid-cooling
appliance hereinafter described.
The plant I employ includes, besides a couple of furnaces, suitable cooling tanks,
and an overhead crane adapted to command the furnaces and the hardening tanks,

page_text: but I only show one furnace, and the crane, the ways it travels on, and the
hardening tanks are not illustrated in the drawings.
The shell produced by casting, or casting and forging, as the case may be, is
prepared to receive and has screwed into it, the combined suspending and liquid-
cooling arrangement represented in Figs. and 4, and to a larger scale in Figs. G
and 7, where a is the shell, al its chamber, a² a forwardly extending portion
thereof which enables the cooling medium to abstract heat more quickly from
the thick mass of metal and thereby prevents cracking; this portion a² is prefer-
ably bored and is so small that it does not appreciably affect the strength of the
shell head. b is a plug which is screwed into the threaded base end of the
chamber a and is made with two holes through it, into one of which are screwed
the inner and outer portions c, e of the inlet pipe, whilst into the other hole is
screwed one end of the outlet pipe d. The upper part of the part c¹ of the inlet
pipe carries a junction piece, into which are screwed to the part of the inlet pipe,
the suspending hook e and the handle f.
Thus it will be understood that, by means of the hook e, the shell, with the
appliances attached to it, can be supported, and that, by means of the handle,
the shell can have imparted to it, during the heating process, sufficient movement,
in a rotary sense, to ensure uniform heating of the shell, which, for this purpose,
is not left in the one position but is continually turned by the attendant.
The shell is first heated in one furnace, very gradually, say for about thirteen
minutes, more or less, and so that it comes out of this furnace at a very dull red
at the point, and only black hot at the shoulder. g is a pot, preferably of cast
steel, into which the point of the shell may be caused to project so as to be thereby
protected during the process of heating in the first furnace and prevented from
becoming overheated, as it would otherwise be liable to do, in consequence of being
of thinner section than other parts of the shell, and therefore heating more
rapidly.
The shell is then placed into the second furnace for completion of the heating
operation; it is kept in that second furnace, say about fourteen minutes, more
or less, so as to bring the point and shoulder (which are again protected by a
pot g) to a temperature suitable for hardening, say to a bright red or low yellow
heat gradually tapering off until, for example, in a 6" shot which is 18" long,
it dies out entirely at about 7" from the base, that is to say, until 7" down from
the base there is no visible appearance of heating. It is important that the
portion which is to be hard be kept at as uniform a temperature as practicable.
The heating is not pressed much at first; it is desirable to get a covering of
soot on the projectile, as this is useful in preventing overheating and oxidation.
As the correct temperature for quenching is approached, care must be exercised
to prevent overheating, and consequent water-cracking-or underheating, and
consequent failure to secure the required hardness.
During the heating, the room must be practically light-proof, darkness being
necessary to obviate confusion arising from various shades of light; sliding roof
doors, easily adjusted, give sufficient light when the heating operation is over.
The indication that the proper temperature has been attained will, to some
extent, vary according to the particular temper of steel, but a workman accustomed
to tempering shell will be able to judge from the appearance when the correct
temperature has been attained.
The shell must be thoroughly heated through. In some cases, the interior of
the chamber, that is, for a certain distance, say, about 1" to 2" from the bottom
may be hardened; when the shell is cold, it can be readily determined by the
use of a round file inserted into the chamber of the shell whether the desired
hardening has been effected.
As will be seen from the drawing, only about one half of the entire length of
the shell extends into the furnace; the point and shoulder will thus be heated most
whilst the remaining portion of the shell will remain comparatively cool, decreasing
in temperature towards its base.

page_text: For example, on a 6" shell, 18" long. I consider it advantageous to aim at about
from 9" to 9" of unfileable portion, measuring from the point.
The shell, after attaining the desired temperature, is then rapidly removed to
the hardening tank. I have found it advantageous to use water only in the tank
keeping it at a temperature of about 80° F.
The inlet tube c² (see Fig. 5) is connected, preferably whilst the shell is
travelling from the furnace to its position in the hardening tank, in some suitable
way such as by an india rubber pipe-to the service main, in which the liquid
should be at a high pressure (say for example, by preference, a pressure of about
75 lbs. per square inch). I so arrange the supply that the exact quantity of
liquid passing through the chamber of the shell may be known, and I aim at
keeping this as nearly uniform as practicable.
A short time, say five seconds, or thereabout before and during the whole period
of the immersion of the shell in the tank, cooling liquid such as water or oil at
a temperature of 60° F. or thereabout is allowed to pass through the chamber of
the shell. This enables the contraction to be led from the centre. If it be
desired not to cool the interior of the chamber so quickly the temperature of the
water may be increased. Or if it be desired to cool the chamber still more slowly
steam or compressed air may be passed through the chamber.
For a short time, say a second or two, before or at the commencement of the
immersion, or during the immersion of the shell, steam comes from the outlet
pipe, followed by water, first at a high temperature, but quickly cooling down.
When it is not desired to harden the interior of the shell I often find it
advantageous to employ as the liquid for cooling the chamber of the shell a mixture
of water and oil, or during the first few seconds of the cooling (or more than this,
if requisite) I pass through the chamber oil only, this being followed by a mixture
of oil and water or by water only the supply of the liquids being continuous. In
this case the oil is pumped or driven through the chamber from an independent
source or sources. If desired, various cooling liquids may be passed through the
chamber successively, the liquids being supplied from independent sources com-
munication with which is controlled by a series of cocks so arranged that any one
or more of them can be operated without interfering with the others or with the
main supply of water.
I have obtained satisfactory results in a six inch shell by using water and whale
oil, passing about one gallon of oil through the chamber before admitting the
water.
In some cases it may be desirable to pass oil through the chamber during the
whole of the cooling operation this being varied according to the hardness it is
desired to give the projectile.
If the shell be made too hard, then it may break at once. If it be not hard
enough, the heating operation must be repeated, care being taken to heat the
once-hardened shell much more slowly, for which purpose I find it convenient to
first place it on the top of the furnace until it becomes too hot to touch by hand.
In order to ascertain if each shell is hardened to a certain length on the outside,
and also if the interior is hardened at the bottom of the chamber, the operator
should test the shells with a file. The hardening zone will, as is well understood,
vary to some extent, according to the calibre of the shell, and the qualities and
thickness of the plate the shell is intended to pierce.
I immerse the shell completely, as distinguished from merely dipping it as far
as the hardening line.
A convenient size of quenching tank for shell of 6" calibre is about 3 ft. square,
and although somewhat larger shell might be quenched in tanks of these dimen-
sions, it is advisable to have proportionately larger tanks for larger calibre of
shell. The temperature of the water in the tank should be 80° F. or there-
about, and the shell should remain immersed. in the case, for example, of shell 6"
by 18" long, say for from 15 to 18 minutes or thereabout and then removed when

page_text: quite cold. The temperature of the water in the tank will then usually be 88° F.
or thereabout.
The tank is kept supplied with fresh cold water in any convenient manner,
usually by means of a pipe passing up through the bottom of the tank and so
arranged that the water supplied through it will play upon the down-turned point
and the shoulder of the shell.
I take the temperature of the liquid in the tank at frequent intervals, say every
quarter of a minute, as well as the temperature of the water escaping from within
the shell.
The temperatures thus obtained serve to indicate, approximately, whether the
shell has been hot enough, and whether the hardening process has been correctly
carried out in the particular case. The exact hardening zone is first determined
by the specification the shell has to meet; if intended for penetrating a thick
plate, the hardening zone of the shell must be greater, in which case the risk of
fracture would be greater.
But if the operation be carried out carefully, and the shell be thoroughly sound
and free from defects, the risk of breakages may generally be confined to a small
percentage.
I sometimes, according to this invention, cast projectiles of an alloy of iron,
carbon, chromium and nickel, containing also silicon or aluminium, or both silicon
and aluminium, in certain suitable proportions, and afterwards harden them, in
the manner and by the means hereinabove described.
Sometimes I use like alloys, and produce therefrom, in the manner set forth
in the Specification of my former Patent No. 3237/92, projectiles combining a
forged point, or forged point and shoulder, with a cast body and base, which pro-
jectiles I harden, substantially in the manner, and by the means hereinabove
described.
Figs. 8, 9 and 10 show some forms of projectiles that can be produced, as
hereinabove described.
In Fig. 9 the projectile is furnished with a point of softer metal than the body
of the projectile.
In Fig. 9 the body a is made flat at a* and has screwed to it a nose, a³, of softer
metal. The body a may, for example, be of alloy such as hereinabove indicated,
and the nose a³ of soft steel.
In Fig. 10 the body a has a pointed nose, over which there is applied a cap a
of softer metal such as soft steel or the cap may be of manganese steel.. Thus, for
example, the body a may be of alloy such as hereinabove indicated, and the cap a
of soft steel shrunk on to the pointed end of body a.
But other forms of projectiles may also be manufactured in accordance with
my present invention.
I sometimes produce cast armour piercers by casting of steel made by the
pneumatic method and subsequently hardening.
I sometimes harden forged projectiles in the manner hereinabove described.
1000
Date way
1000
1030.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Chartered Patent Agent.
COMPLETE SPECIFICATION.

page_text: what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement;-
-
My invention has for object the manufacture, in an economical manner, of steel
armour-piercing projectiles of an efficient kind, produced by casting, or it may
be by forging, or partly by casting and partly by forging (see the Specification of
my Patent No. 3237/92).
Of any suitable alloy I cast a hollow projectile, of any desired form, in a mould
of appropriate construction.
In the manufacture of hardened shells in the manner hereinafter described I
sometimes cast the shells in moulds point downward, and, in order to prevent
settling or falling away from the core, I use a core formed (as described in the
Specification of my former Patent No. 24453 of 1895) of sand or composition but
having at its point a cast iron, steel or other metal tip which chills or sets the
steel forming the adjacent portion of the shell more quickly. By this means a
projectile is obtained practically free from settling or shrinkage cavities, thereby
considerably reducing the risk of cracks resulting from the hardening process.
The construction of the mould employed is varied according to the shell to be
produced. Thus if the head of the shell is to be thick and the walls thin, the head
portion of the mould is made of iron so as to rapidly chill the steel therein, whilst
the body portion is of sand so that the wall part of the shell remains fluid and
feeds metal to the head part as it sets. If the walls and head are to be of fairly
uniform thickness the shell may be cast entirely in an iron mould or chill, as is
well understood.
If the projectile is to have a forged point, or forged point and shoulder, I produce
it after the manner described in the Specification of my former Patent No. 3257/92,
already mentioned.
I effect the hardening of the projectile as I will now proceed to explain with
reference to Figs. 1 to 7 inclusive of the illustrative drawings left with my pro-
visional specification, premising that, as will be evident, the details are susceptible
of modification according to requirement.
Fig. 1 shows a tempering furnace in front elevation.
Fig. 2 shows a plan of the furnace.
Fig. 3 shows a horizontal section through line A A of Fig. 4.
Fig. 4 shows a vertical section through line B B of Fig. 3.
Fig. 5 shows a vertical section through line C C of Fig. 2.
Figs. 6 and 7 show, to a larger scale, vertical sections, in planes at right angles
to one another of a shell with its point in a pot, and with internal liquid-cooling
appliance hereinafter described.
The plant I employ includes, besides a couple of furnaces, suitable cooling tanks,
and an overhead (or equivalent) crane adapted to command the furnaces and the
hardening tanks, but I only show one furnace, and the crane the ways it (if an
overhead one) travels on, and the hardening tanks are not illustrated in the
drawings.
The shell, produced by casting, or by forging, or by casting and forging, as the
case may be, is prepared to receive and has screwed into it, the combined sus-
pending and liquid-cooling arrangement represented in Figs. 1 and 4, and to a
larger scale in Figs. 6 and 7, where a is the shell, al its chamber, a² a forwardly
extending portion thereof which enables the cooling medium to abstract heat
more quickly from the thick mass of metal and thereby prevents cracking; this
portion is preferably bored and is so small that it does not appreciably affect
the strength of the shell head. The forwardly extending portion a² of the chamber
as the drawing shows is a specially formed recess, not produced by continuing the
inner surface of the chamber wall in its normal direction but quite independently
of the contour of the wall of the main portion a¹ of the chamber the portion a² is
made of small diameter and extends for a suitable distance in an axial direction
towards the point of the projectile. is a plug which is screwed into the threaded

page_text: base end of the chamber and is made with two holes through it, into one of
which are screwed the inner and outer portions c, c¹ of the inlet pipe, whilst into
the other hole is screwed one end of the outlet pipe d. The upper part of the
part of the inlet pipe carries a junction piece, into which are screwed the part ²
of the inlet pipe, the suspending hook e and the handle f.
Thus it will be understood that, by means of the hook e, the shell; with the
appliances attached to it. can be supported, and that, by means of the handle,
the shell can have imparted to it, during the heating process, .sufficient movement,
in a rotary sense, to ensure uniform heating of the shell, which, for this purpose,
is not left in the one position, but is continually turned by the attendant.
The shell is first heated in one furnace, very gradually, say for about forty five
minutes, more or less, and so that it comes out of this furnace at a very dull red
at the point, and only black hot at the shoulder. g is a pot, preferably of cast
steel into which the point of the shell might be caused to project so as to be thereby
protected during the process of heating in the first furnace and prevented from
becoming overheated, but I do not as a rule deem it needful to use such a pot in
the first furnace.
The heating is not pressed much at first; it is desirable to get a covering of
soot on the projectile, as this is useful in preventing overheating and oxidation,
especially in the second furnace, in which there obtains a higher temperature than
in the first furnace.
After heating in the first furnace, the shell is placed in the second furnace for
completion of the heating operation; it is kept in that second furnace, say about
twenty minutes, more or less, so as to bring the point and shoulder (which are
protected by a pot g such as already referred to to a temperature suitable for
hardening, say to a bright red or low yellow heat, gradually tapering off until,
for example, in a 6" shot, which is 18" long, it dies out entirely at about 7" from
the base, that is to say, until 7" down from the base there is no visible appearance
of heating. It is important that the portion which is to be hard be kept at as
uniform a temperature as practicable. The use of the pot in the second furnace
is important, as the point or extreme ogival portion will heat much more rapidly
than the main body, consequently without the pot it might well happen that the
point of the projectile would be burnt, thus involving risk of this part fracturing
during the quenching process, an evil I aim at preventing by the use of the pot
as described.
As the correct temperature for quenching is approached, care must be exercised
to prevent overheating, and consequent water-cracking or underheating, and
consequent failure to secure the required hardness.
During the heating, the room must be practically light-proof, practical dark-
ness being necessary to obviate confusion arising from various shades of light;
sliding roof doors, easily adjusted, give sufficient light when the heating operation
is over.
The indication that the proper temperature has been attained will, to some
extent, vary according to the particular temper of steel, but a workman accustomed
to tempering shell will be able to judge from the appearance when the correct
temperature has been attained.
The front portion of the shell must be thoroughly heated through. In some
cases, the interior of the chamber, that is, for a certain distance, say, about 1"
to 2" from the bottom (i.e. the nose end of the chamber) may be hardened; when
the shell is cold, it can be readily determined, by known means (as for example
by the use of a file inserted into the chamber of the shell) whether the desired
hardening has been effected.
As will be seen from the drawing, only about one half of the entire length of
the shell extends into the furnace; the point and shoulder will thus be heated most
whilst the remaining portion of the shell will remain comparatively cool, decreasing
in temperature towards its base, where it will not be hot enough to be subsequently
affected by the quenching temperature.

page_text: For example, on a 6" shell, 18" long, I consider it advantageous to aim at about
from 9" to 9" of unfileable portion, measuring from the point.
By the use of two furnaces I am enabled to expedite the progress of the work,
as, whilst the heating of one projectile is being completed in the second furnace,
another can be preliminarily heated in the first furnace.
!-
The shell, after attaining the desired temperature, is then rapidly removed to
the hardening tank. I have found it advantageous to use water only in the tank
keeping it at a temperature of about 80° F.
The inlet tube (see Fig. 5) is connected, preferably whilst the shell is
travelling from the furnace to its position in the hardening tank, in some suitable
way such as by an india rubber pipe-to the service main, in which the liquid
should be at a high pressure (say, for example, by preference, a pressure of about
75 lbs. per square inch). I so arrange the supply that the exact quantity of
liquid passing through the chamber of the shell may be known, and I aim at
keeping this as nearly uniform as practicable. The water can be passed through
a suitable heating apparatus to raise it to the desired temperature, and, if
necessary, means are employed for maintaining the required pressure.
A short time, say five seconds, or thereabout before and during the whole period
of the immersion of the shell in the tank, cooling liquid such as water or oil at
a temperature of 60° F. or thereabout is allowed to pass through the chamber of
the shell. This enables the contraction to be led from the centre. If it be
desired not to cool the interior of the chamber so quickly the temperature of the
water may be increased. Or if it be desired to cool the chamber still more slowly
steam or compressed air may be passed through the chamber.
For a short time, say a second or two, before or at the commencement of the
immersion, or during the immersion of the shell, steam comes from the outlet
pipe, followed by water, first at a high temperature, but quickly cooling down.
When it is not desired to appreciably harden the interior of the shell I often find it
advantageous to employ as the liquid for cooling the chamber of the shell a mixture
of water and oil, or during the first few seconds of the cooling (or more than this,
if requisite) I pass through the chamber oil only, this being followed by a mixture
of oil and water or by water only the supply of the liquids being continuous. In
this case the oil is pumped or driven through the chamber from an independent
source or sources. If desired, various cooling liquids may be passed through the
chamber successively, the liquids being supplied from independent sources
munication with which is controlled by a series of cocks so arranged that any one
or more of them can be operated without interfering with the others or with the
main supply of water.
com-
I have obtained satisfactory results in a six inch shell by using water and whale
oil, passing about one gallon of oil through the chamber before admitting the
water.
In some cases it may be desirable to pass oil through the chamber during the
whole of the cooling operation this being varied according to the hardness it is
desired to give the projectile.
If the shell be made too hard, then it may break at once. If it be not hard
enough, the heating operation must be repeated, care being taken to heat the
once-hardened shell much more slowly, for which purpose I find it convenient to
first place it on the top of the furnace until it becomes too hot to touch by hand.
In order to ascertain if each shell is hardened to a certain length on the outside,
and also if the interior is hardened at the bottom of the chamber, the operator
should test the shells with a file. The hardening zone will, as is well understood,.
vary to some extent, according to the calibre of the shell, and the qualities and
thickness of the plate the shell is intended to pierce.
I immerse the shell completely, as distinguished from merely dipping it as far
as the hardening line.
-A convenient size of quenching tank for shell of 6" calibre is about 3 ft. square,
and although somewhat larger shell might be quenched in tanks of these dimen-

page_text: sions; it is advisable to have proportionately larger tanks for larger calibre of
shell. The temperature of the water in the tank should be 80° F. or there-
about, and the shell should remain immersed, in the case, for example, of shell 6"
by 18" long, say for from 15 to 18 minutes or thereabout and then removed when
quite cold.
The temperature of the water in the tank will then usually be 88° F.
or thereabout.
The tank is kept supplied with fresh cold water (i.e. water at a temperature of
about 60° Fah.) in any convenient manner, usually by means of a pipe passing
up through the bottom of the tank and so arranged that the water supplied through
it will play upon the down-turned point and the shoulder of the shell.
I take the temperature of the liquid in the tank at frequent intervals, say every
quarter of a minute; as well as the temperature of the water escaping from within
the shell.
The temperatures thus obtained serve to indicate, approximately, whether the
shell has been hot enough, and whether the hardening process has been correctly
carried out in the particular case. The exact hardening zone is first determined
by the specification the shell has to meet; if intended for penetrating a thick
plate, the hardening zone of the shell must be greater, in which case the risk of
fracture would be greater.
But if the operation be carried out carefully, and the shell be thoroughly sound
and free from defects, the risk of breakages may generally be confined to a small
percentage.
I sometimes, according to this invention, cast projectiles of an alloy of iron,
carbon, chromium and nickel, containing also silicon or aluminium, or both silicon
and aluminium in certain suitable proportions, as set forth. in the Specification
of my previous application for Patent No. 27754 of 1897 and afterwards harden
them, in the manner and by the means hereinabove described.
I sometimes, according to this invention, produce projectiles by forging steel of
like alloys as set forth in the specification of my previous application for Patent
No. 27755 of 1897, and afterwards harden them in the manner and by the means
hereinabove described.
Sometimes I use like alloys, and produce therefrom, in the manner set forth
in the Specification of my former Patent No. 3237/92, projectiles combining a
forged point, or forged point and shoulder, with a cast body and base, which
projectiles I harden, substantially in the manner, and by the means hereinabove
described.
Figs. 8, 9 and 10 show some forms of projectiles that can be produced, as
hereinabove described.
In Fig. 9 the projectile is furnished with a point of softer metal than the body
of the projectile.
In Fig. 9 the body a is made flat at a* and has screwed to it a nose a³ of softer
metal. The body a may, for example, be of alloy such as hereinabove indicated,
and the nose a³ of soft steel.
In Fig. 10 the body a has a pointed nose, over which there is applied a cap c
of softer metal such as soft steel or the cap may be of manganese steel. Thus, for
example, the body a may be of alloy such as hereinabove indicated, and the cap a
of soft steel shrunk on to the pointed end of body a.
But other forms of projectiles may also be manufactured in accordance with
my present invention.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In the manufacture of projectiles, the method of hardening which consists
in protecting the point of the projectile and gradually heating the point and
shoulder thereof to a temperature suitable for hardening, and finally cooling the
projectile by complete immersion in a cooling liquid.

page_text: 2. In the manufacture of projectiles, the method of hardening which consists in
gradually heating the point of the projectile to a dull red, continuing the heating
until the point and shoulder are brought to a temperature suitable for hardening;
removing the projectile from the furnace and circulating a cooling medium
through the chamber of the projectile, and completely immersing the projectile
in a cooling fluid after the internal cooling has been initiated.
3. In the manufacture of projectiles, the method of hardening which consists
in gradually heating the point to a dull red; removing the projectile to a second
furnace and continuing the heating until the point and shoulder are brought to
a hardening temperature, protecting the point from direct action of the heat; and
finally cooling the projectile.
4. In the manufacture of projectiles, the method of hardening which consists
in heating the point and shoulder of the projectile to a temperature suitable for
hardening, protecting the point from the direct action of the heat, to prevent
overheating thereat, and cooling the projectile initially from its interior and
subsequently by complete immersion in a cooling medium.
5. In the manufacture of projectiles, the method of hardening which consists
in suspending the projectile point down in a furnace, and gradually heating the
point and shoulder of the projectile to a hardening temperature while protecting
the point from the direct action of the heat, and finally completely immersing
the projectile in a cooling medium.
6. In the manufacture of projectiles, the method of hardening which consists in
raising the temperature of the point and shoulder to a bright red or a low yellow
heat by successive heatings while protecting the point from the direct action of
the heat circulating a cooling medium under pressure through the chamber after
removal of the projectile from the furnace, and completely immersing the pro-
jectile in a cooling medium after internal cooling and hardening has begun.
7. In the manufacture of projectiles, the method of hardening which consists in
raising the temperature of the point and shoulder to a bright red or a low yellow
heat by successive heatings while protecting the point from the direct action of
the heat circulating a cooling medium under pressure and at a temperature of
about 60° F. through the chamber of the projectile, beginning before and con-
tinuing throughout immersion; and completely immersing the projectile in a
cooling liquid having a temperature of about 80° F. until the projectile quite
cool.
8. In the manufacture of projectiles, the method of hardening which consists
in rotating or partially turning the projectile, suspended point downwards in a
furnace, and gradually heating the point and shoulder to a hardening temperature
while protecting the point from the direct action of the heat; removing the pro-
jectile from the furnace to a hardening tank, completely immersing the projectile
therein in a cooling medium, and circulating a cooling medium under high pressure
through the chamber of the projectile after its removal from, the furnace.
9. In the manufacture of chambered projectiles, the method of hardening which
consists in heating the point and shoulder to a temperature suitable for hardening,
circulating through the chamber of the projectile a cooling medium which is
supplied at the forward end of said chamber and withdrawn from the rear end
thereof, and finally completely immersing the projectile in a cooling medium.
10. In the manufacture of chambered projectiles, the method of hardening which
consists in suspending the projectile point downwards with more or less of its
front portion in a furnace, and gradually heating the point and shoulder to a
hardening temperature while protecting the point from the direct action of the
heat removing the projectile from the furnace to a hardening tank, circulating
a cooling medium through the chamber of the projectile and completely immersing
the projectile in a cooling medium in the said hardening tank.
11. In the manufacture of projectiles, the method of hardening which consists
in raising the temperature of the point and shoulder to a temperature suitable for

page_text: hardening while protecting the point from being overheated by means of a pot,
and finally cooling the projectile.
12. In the manufacture of chambered projectiles the method of hardening which
consists in suspending the projectile point downwards with more or less of its
front portion within the heating chamber of a furnace, protecting the point from
the direct action of the heat, gradually heating the projectile until the point
becomes a dull red, removing the projectile to and similarly suspending it in a
second furnace continuing the heating in such second furnace until
the point and shoulder of the projectile are brought to a bright red
or low yellow heat, then removing the projectile from the furnace to a
hardening tank, connecting the chamber of the projectile through circulating
means to a source of supply of some suitable cooling medium such as water, or oil
or steam, or compressed air, feeding cooling medium to the forward end of the
chamber of the projectile and withdrawing it from the rear end, completely immer-
sing the projectile in cooling medium in a tank after the cooling of the chamber
has been started retaining the projectile in the cooling medium and simultaneously
causing cooling medium as it enters the tank to play upon the point of the
projectile.
13. The herein described improved manufacture of projectiles by casting or
casting and forging, or forging, of an alloy of iron, carbon, chromium and nickel,
containing also silicon or aluminium, or both silicon and aluminium and after-
wards hardening substantially in the manner and by the means hereinabove
described.
14. The hercinabove described improved manufacture of projectiles by casting
in a mould having a head portion of iron a hody portion of sand, and a sand or
composition core provided or not with a metal tip at its point, and hardening the
casting substantially in the manner hereinbefore described.
15. The hereinabove described improved manufacture of projectiles producing
the same partly by casting and partly by forging according to my Patent No. 3237
of 1892, and hardening substantially in the manner herein before described.
16. In the manufacture of chambered projectiles, forming the chamber with a
forwardly extending portion such as a², substantially as herein before described
with reference to and shown in Figs. 6 and 7 of the accompanying drawings for
the purpose of enabling the cooling medium to abstract heat more quickly from
the thick mass of metal forming the head.
17. In the manufacture of chambered projectiles, the use of apparatus sub-
stantially such as described with reference to and illustrated in Figs. 1, 4, 6 and 7
of the drawings for circulating in the manner described a cooling medium through
the chamber of the projectile, whether or not such apparatus have combined with
it parts whereby it is adapted to serve also for use in rotating the projectile during
the heating process, as set forth.
18. In the manufacture of projectiles, the improved method of hardening
hereinabove described with reference to the drawings.
Dated this 8th day of December 1898.