Improvements in the Manufacture of Compound Armour Plates.
Year: 1886

page_text: Date of Application, 26th Nov., 1886.
Complete Left, 27th July, 1887.
Complete Accepted, 2nd Sept., 1887.
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Compound Armour Plates.
I, ALEXANDER WILSON of the Cyclops Works, Sheffield in the County of York
Engineer do hereby declare the nature of this invention to be as follows:-
The object of this invention is to produce by means of my well known methods,
compound armour plates with a very hard face, and an extremely soft and tough
back although these plates are somewhat similar to those produced by and,described
in my Specifications of Patents No. 3472, September 14th 1887 and No. 2130,
May 5th 1882, they are an improvement thereon, inasmuch as I can make the
"backing" portion of the plate, with proper manipulation, both stronger and tougher
than heretofore.
In order that my improvements shall be understood, I may say that to produce a
compound plate from the commencement, which must be 20 ins. thick when finished,
I proceed as follows:-
I take a wrought iron fibrous plate say about 15 ins. thick; which has been
previously built up from a number of thinner ones, in the usual manner, and whilst
hot from the rolls, hammer or press; and put it into a cast iron or wrought iron
box, or "mould as described in my before mentioned Specifications of Patents-the
"mould is made internally of the proper length, breadth and depth; the depth for
the plate in question would be about 28 ins., this would enable me to fuse on to the
exposed surface of the "fibrous "iron plate a layer of "ingot iron" about 13 ins. in
thickness, thus forming a plate of 28 ins. thick.
I then take the plate out of the mould as soon as desirable and put it into a
re-heating furnace, and after re-heating it to the proper temperature, I subject it to
the action of a rolling mill, hammer or press until it becomes reduced to about 18 ins.
in thickness, this is now what I term the "iron backing" of the compound plate. I
then put it into the mould again, the depth of which can be easily altered, then run
or fuse on to the other side of the fibrous iron plate, a layer of hard steel, say about
Sins. in thickness, the plate is now in its rough state about 26 ins. thick. I then
take the plate out of the "mould "and put it into the same or other reheating furnace,

page_text: and expose it to the action thereof for a comparatively short time, after which I roll,
hammer, or press the plate to the desired or finished thickness viz. 20 inches; the
plate is then allowed to cool; afterwards it is planed and otherwise machined to the
proper form and dimensions.
It will be observed that I subject the "backing" portion of the plate to a great
amount of mechanical manipulation and pressure to increase its strength and
toughness before I fuse on the hard steel "face," this I consider most important, as
the latter portion of the plate can be made sufficiently hard to prevent penetration
without its having to undergo any mechanical pressure or manipulation whatever.
Although in some cases I may prefer to do so, as in my former methods.
<<
And in order that my improvements shall be further understood 1 may say that I
make the "ingot iron," which I fuse on to the fibrous iron plate to form the
backing," as soft and as low in carbon, or nearly so, as the best brands of Yorkshire
irons, which when rolled or hammered will give a tensile strain of 26 to 30 tons per
square inch and the steel which I propose to fuse on to the fibrous iron plate to form
the "face" I make of a very high temper say containing from 1.25 to 15 per cent. of
carbon or thereabouts which will be very hard and will offer great resistance to
penetration of projectiles. The ingot iron and steel can be produced by either of the
processes commonly known as Bessemer and Siemens Martin," the centre
portion of the plate I make of the best puddled fibrous iron.
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"face" as
It will now be easily seen that I can produce a plate which will have
hard as can be planed or otherwise machined, which will enable it to break up any
projectiles that may be fired against it, and will resist the penetration thereof, whilst
the back of the plate will be made tough and ductile, having also great tensile
strength to enable it to better support the front layers of the plate, and by retaining
the fibrous iron "core" or centre portion, I produce a plate which is not homogeneous
but stratified, therefore any fractures or cracks which may be produced on the hard
face of the plate, by the impact of projectiles will not extend through the full thickness
of the plate, this I also consider most important, as it is a well known fact that
homogeneous plates, made wholly of steel, or other hard metals, either in layers or
otherwise have this failing, and that all cracks produced on the surface, by impact
or otherwise, do extend right through the full thickness of the plates, there being no
fibrous strata to prevent it.
Although I have specified the various thicknesses and tempers of steel and iron
layers of a 20" compound plate made by this improved method, it must be under-
stood that I do not bind myself to strictly adhere to them as I may have to, or could
do if necessary, alter them to suit other circumstances.
Dated this 26th day of November 1886.
CARPMAEL & Co.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION,
Improvements in the Manufacture of Compound Armour Plates.
I, ALEXANDER WILSON of the Cyclops Works, Sheffield in the County of York
Engineer 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 :-
The object of this invention is to produce compound armour plates with a very
hard face, and an extremely soft and tough back. Although the plates as I now
make them are somewhat similar to those produced by and described in my Specifi-
cations of Patents No. 3472, September 14th 1877 and No. 21.30, May 5th 1882, they
are an improvement thereon, inasmuch as I can make the backing portion of the
plate, with proper manipulation, both stronger and tougher than heretofore.
In order that my improvements shall be understood, I will describe the way in
which I now proceed to produce a compound plate 20 ins. thick when finished.
;
I take a wrought iron fibrous plate say about 15 ins. thick which has been
previously built up from a number of thinner ones, in the usual manner, and whilst
it is still hot from the rolls, hammer or press used for forging it I put it into a cast
iron or wrought iron box or mould as described in my before mentioned Specifi-
cations of Patents-the mould is made internally of the proper length, breadth and
depth; the depth for the plate in question would be about 28 ins., this would enable
me to fuse on to the exposed surface of the "fibrous" iron plate a layer of "ingot
iron about 13 ins. in thickness, thus forming a plate of 28 ins. thick.
::
I then take the plate out of the mould as soon as desirable and put it into a
re-heating furnace, and after re-heating it to the proper temperature, I subject it to
the action of a rolling mill hammer or press until it becomes reduced to about 18 ins.
in thickness, this is now what I term the iron backing of the compound plate. I
then put it into the mould again, the depth of which can be easily altered, then run
or fuse on to the other side of the fibrous iron plate, a layer of hard steel, say about
Sins. in thickness, the plate is now in its rough state about 26 ins. thick. I then
take the plate out of the mould" and put it into the same or other reheating furnace,
and expose it to the action thereof for a comparatively short time, after which I roll,
hammer, or press the plate to the desired or finished thickness viz. 20 inches; the
plate is then allowed to cool; afterwards it is planed and otherwise machined to the
proper form and dimensions.
It will be observed that I subject the backing" portion of the plate to a great
amount of mechanical manipulation and pressure to increase its strength and
toughness; before I fuse on the hard steel "face," this I consider most important, as
the latter portion of the plate can be made sufficiently hard to prevent penetration
without its having to undergo any mechanical pressure or manipulation whatever.
Although in some cases I may prefer to do so, as in my former methods.
And in order that my improvements shall be further understood I may say that I
make the ingot iron," which I fuse on to the fibrous iron plate to form the

page_text: ::
"backing" as soft and as low in carbon, or nearly so, as the best brands of York-
shire irons, which when rolled or hammered will give a tensile strain of 26 to 30 tons
per square inch-and the steel which I propose to fuse on to the fibrous iron plate to
form the face I make of a very high temper say containing from 125 to 15 per
cent. of carbon or thereabouts which will be very hard and will offer great resistance
to penetration of projectiles. The ingot iron and steel can be produced by either of
the processes commonly known as "Bessemer" and "Siemens Martin," the centre
portion of the plate I make of the best puddled fibrous iron.
It will now be easily seen that I can produce a plate which will have a face as hard
as can be planed or otherwise machined, which will enable it to break up any pro-
jectiles that may be fired against it and will resist the penetration thereof, whilst the
back of the plate will be made tough and ductile, having also great tensile
strength to enable it to better support the front layers of the plate, and by retaining
the fibrous iron "core" or centre portion, I produce a plate which is not homogeneous
but stratified, therefore any fractures or cracks which may be produced on the hard
face of the plate, by the impact of projectiles will not extend through the full thickness
of the plate, this I also consider most important, as it is a well known fact that
homogeneous plates, made wholly of steel, or other hard metals, either in layers or other-
wise have this failing, and that all cracks produced on the surface, by impact or
otherwise, do extend right through the full thickness of the plates, there being no
fibrous strata to prevent it.
Although I have specified the various thicknesses and tempers of steel and iron
layers of a 20% compound plate made by this improved method, it must be understood
that I do not bind myself to strictly adhere to them as these may be altered without
departing from my invention.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed I declare that what I claim is :-
The process herein before described of manufacturing armour plates consisting in
taking a wrought iron fibrous plate hot as it comes from the rolls or other forging
apparatus and putting it into a mould and casting on to one of its faces a layer of
soft ingot iron, then faking the plate out of the mould and after reheating and rolling
or otherwise forging it to give it additional strength and toughness placing it again
into a mould and casting a layer of steel on to the opposite side to that which
previously had the layer of soft ingot iron cast on to it.
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