Improvements in the Manufacture of Metal Slabs or Plates or other Articles, more especially Armour Plates and Projectiles.
Year: 1894

page_text: Date of Application, 25th Oct., 1894
Complete Specification Left, 22nd Apr., 1895-Accepted, 1st June, 1995
Improvements in the Manufacture of Metal Slabs or Plates or other
Articles, more especially Armour Plates and Projectiles.
I, JOHN ALEXANDER HUNTER of 715 South 16th Street in the City and
County of Philadelphia, State of Pennsylvania in the United States of America
Doctor of Medicine do hereby declare the nature of this invention to be as
follows:-
This invention relates to the manufacture of slabs or plates or other articles
baving a hard resisting surface, and a softer and more yielding backing.
In carrying out my invention I first produce by casting or otherwise a soft steel
plate and then while the same is in a highly heated condition I cast upon the face
thereof a layer of iron which is afterwards subjected to any of the usual processes
whereby partial decarbonization of the same is effected for the purpose of
converting the iron into steel capable of being hardened and tempered, which
hardening and tempering is then effected throughout the whole or a part of the
mass.
By this means I am enabled to produce a plate having a surface of any desired
degree of hardness and a back of softer metal, the two being firmly united, as it
has been found in practice that by casting a mass of iron upon the face of a body
of highly heated steel, an intimate union of the two bodies is effected and a
homogeneous block or plate is produced.
The following description illustrates by way of an example how this invention
may be carried out.
A body of steel is first run into the bottom of a mould and the body of cast iron is
then poured in upon the top of the said mass of steel, the greater specific gravity
of the latter being relied upon to prevent the disturbance of the same by the
pouring of the iron on the top thereof it is preferable to permit the steel to
partially cool before pouring the iron into the mould, the steel however should
still retain a high degree of heat when the iron is brought into contact with it, or
a steel plate, slab or block produced in any available manner may be first highly
heated and then introduced into the mould in order to provide a base upon which
to pour the mass of cast iron.
When the composite block has become cold, or sufficiently cool to permit
handling the cast iron portion of the said block is subjected to any of the ordinary
converting operations whereby partial decarbonization of the iron is effected and
the metal is reduced to a condition suitable for being hardened and tempered.
For carrying out this part of the process I may resort to the treatment set forth
in the Specification of my prior British Patent dated the 23rd day of May 1893
and bearing No. 10215 or the iron portion of the composite plate may be subjected to
any of the usual cementation processes and may be afterwards hardened or tempered
in any ordinary manner throughout either the whole or a part of its mass, the mass
of steel forming the backing for the mass of iron being protected from injury or
change during such converting, hardening and tempering operations, so that it
preserves its original character and provides a backing for the hardening or
tempered face of the plate.

page_text: My invention is of special advantage in the manufacture of armour plates or
armour piercing projectiles, the latter having an outer surface of hardened steel
and an interior core or heart of soft steel.
Dated thie 25th day of October 1894.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
Improvements in the Manufacture of Metal Slabs or Plates or other
Articles, more especially Armour Plates and Projectiles.
I, JOHN ALEXANDER HUNTER of 715 South 16th Street in the City and
County of Philadelphia, State of Pennsylvania in the United States of America,
Doctor of Medicine, 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 :―
My invention has for its object to produce slabs or plates or other metal articles
having a hard resisting surface and a softer and more yielding backing. I will in
explaining my invention refer to the accompanying drawings in which the figures
represent a plate in sections shewing successive stages in the preparation of the
plate in accordance with my invention.
Figure 1 shews the plate at the end of the first stage.
Figure 2 at the end of the second stage; and
Figure 3 at the end of the third and last stage.
In carrying out my invention I first produce (by casting or otherwise) a soft
steel plate and then, while the said plate is in a highly heated condition, I cast
upon the face thereof a layer of iron, which is afterwards subjected to any of the
usual processes whereby partial decarbonization of the same is effected for the
purpose of converting the iron into steel capable of being hardened and tempered
which hardening or tempering is then effected throughout the whole.or a part of
its. mass.
By this means I am enabled to produce a plate having a surface of any desired
degree of hardness and a back of softer metal, the two being. firmly united, as it
has been found in practice that by casting a mass of iron upon the face of a body
of highly heated steel, an intimate union of the two bodies is effected and a
homogeneous. block or plate is produced. The following description illustrates by
way of an example how this invention may be carried out.
A body of steel A is first run into the bottom of a mould and the body of
cast iron B is then poured in directly upon the top of the said mass of steel, the
greater specific gravity of the latter being relied upon to prevent the disturbance
of. the same by the pouring of the iron on the top thereof. It is preferable to
permit the steel to partially cool before pouring the. iron into the mould but the
steel, should still retain a high degree of heat when the iron is brought into contact
with it; or a steel plate, slab or block produced in any available manner may be
first highly heated and then introduced into the mould in order to provide a base
upon which to pour the mass of cast iron.
When the composite block such as is shewn in Figure 1 has become cold, or
sufficiently cool to permit of its being manipulated the cast iron portion of the
said block is subjected to any of the ordinary converting operations whereby
partial decarbonization of the iron is effected and the metal is reduced to a
condition suitable for being hardened and tempered, the composite plate at this
stage being represented in Figure 2, where the converted portion of the plate is
represented at 'B'.

page_text: For carrying out this part of the process I may resort to the treatment set forth
in the Specification of Letters Patent No. 10215 dated the 23rd day of May 1893
granted to me, or the iron portion of the composite plate may be subjected to any
of the usual or suitable cementation processes and may be afterwards hardened or
tempered in any ordinary manner throughout either the whole or a part of its mass,
as shewn in Figure 3 where the hardened or tempered portion of the plate is
represented at B³, the mass of steel forming the backing for the mass of iron being
protected from injury or change during such converting, hardening and tempering
operations, so that it preserves its original character and provides a backing for
the hardened or tempered face of the plate.
My invention is of special advantage in the manufacture of armour plates or
armour piercing projectiles, the latter having an outer surface of hard steel and an
interior core or heart of soft steel.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The manufacture of metal slabs or plates or other articles having a hardened
steel face with a soft steel backing by casting a mass of iron upon a backing of
steel, converting the said cast iron mass into steel capable of being hardened or
tempered, and then hardening or tempering the same, substantially as hereinbefore
explained.
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