Improvements relating to the Manufacture of Armour-plates and the like, and to Apparatus therefor.
Year: 1894

page_text: Date of Application; 9th Apr., 1894
Complete Specification Left, '8th Jan 1895-Accepted, 23rd Mar., 1895
PROVISIONAL SPECIFICATION.
Improvements relating to the Manufacture of Armour-plates and
the like, and to Apparatus therefor.
I, VALERE EMILE LÉON DEMENGE, of 21 Boulevard Poissonnière, Paris, in the
Republic of Frauce, Engineer, do hereby declare the nature of this invention to be
as follows:-
My invention relates to the manufacture of armour-plates and the like and to
apparatus therefor. It comprises a process which has for its object to effect the
decreasing cementation of armour plates, not upon the plate after the forging of
the same, but upon the ingot which will be transformed into a plate and during the
casting of the ingot; not upon the metal in the solid and hammered state, but upon
the metal prior to its solidification. I utilize the property of carbon of being
incorporated with the metal and of hardening it much more easily and rapidly when
the metal is liquid than when it is solid.
In the casting I obtain ingots which are very much carburated upon one face and
in which the proportion of carbon decreases with the distance from the face and
with the approach to the opposite face.
For attaining this result it is needful to combine two conditions :
(1) To cover one of the sides of the ingot mould, that corresponding to the face
of the ingot which is to be cemented, with a sufficiently thick layer of carburating
materials which may or may not be united by any agglomerating agent.
(2) To regulate the solidification of the ingot so that it will take place very
rapidly upon one of the faces of the ingot (that which is designed to absorb the
least carbon possible), next successively from this face to the opposite face (that
which has to be hardened) and then as slowly as possible on the side of. this
latter face.
The carburating materials employed (pulverized wood charcoal, coke, anthracite
or the like), agglomerated by tar, molasses or other materials, may be applied to
the side of the ingot mould by any suitable means either as pisé or in the form of
blocks. Various devices may likewise be used for effecting the rapid cooling of one
of the sides of the ingot mould and for preserving its heat at the opposite side on
which the carburating material is provided. For instance I utilize for this purpose
the differences in the conductibility of materials which constitute the sides of the
ingot mould, whose emitting powers may also be varied as regards the outer
surfaces. Moreover I take account of the conditions of cooling by radiation and
give my ingot mould the outer form which is best adapted for obviating too rapid a
cooling at the extreme parts and at the corners of the mould.
I may also change the conditions of cooling in the various parts of the ingot
mould by causing currents of fluids at various temperatures to circulate therein.
The casting of the mould is effected in such a manner that degradations of the
carburated side cannot take place. I may effect this operation either directly by
employing a special apparatus which conducts the metal without any appreciable
force to the level of the liquid and rises at the same time as this level, or in a
simpler manner as hereinafter described.
I use an ingot mould composed of two parts which are connected together. One
of the parts forms three vertical sides concave towards the exterior, and is made of
cast iron. The other part constitutes a slab or metallic plate well fiuished
interiorly; its thickness is greater in the middle and it is convex towards the

page_text: exterior. This part may be made either of cast iron or steel or of an alloy of cast.
iron and another metal which is a better conductor than iron, such as copper. The
bottom of the ingot mould is made of cast iron, but it is of a certain thickness and
a prismatic incision is formed therein throughout its width so as to enable fire
bricks formed with a bevel to be sunk therein. In the middle brick is provided
the conduit for conveying the metal against the foot of the slab of the ingot
mould.
If the
A wall made of blocks of carbon is sunk into masonry of fire bricks filling the
corners of the ingot mould. The blocks of carbon have a thickness of at least
40 millimetres. The carbon employed is wood charcoal, anthracite or coke
deprived of ashes as much as possible. According as it is desired to facilitate or
diminish the absorption of carbon the thickness of the grains-varies from 1 to
4 millimetres sideways. The agglomeration is obtained by means of tar freed from
its water and from its light oils, or by means of molasses. If the metal is not
absolutely deoxidized it is expedient to mix with the blocks thin strips of aluminium
in the proportion of Toon relatively to the weight of the metal to be cast.
metal is well deoxidized this precaution is not needed. The blocks are subjected to
a strong compression in a very regular mould and then freed from the greatest
quantity possible of the volatile materials which they contain by any known process
of drying or distillation. The process which appears to succeed best in practice
consists in heating the blocks of coal to a red heat in a closed vessel so as to free
them completely from the volatile materials which they contain. However, in order
that the blocks thus treated may possess a sufficient strength the size of the grains
of coal should be about 4 millimetres. The small faces of the blocks should be very
regular, they should rest directly one upon the other without interposition of clay
grout, no scratch should be produced at the corners, and the blocks should be strong
enough to be handled without fear. The wall made of blocks of coal is constructed
in such a manner that the joints cross each other; moreover each block of coal
ests upon a bed of clay covering the masonry of fire bricks which lines the
metallic side of the first part of the ingot mould. The parts built of fire bricks
must terminate in a point in order to obtain a continuous decrease in the
conductibility of the sides, and the space into which the metal is cast constitutes a
rectangle.
It is easy to obtain the adherence of this masonry to the metal of the ingot mould
by providing in the interior side of the latter dove-tail grooves or by employing any
other means.
The thickness of the layer of masonry made of fire bricks placed between the
metal of the ingot mould and the wall consisting of blocks of coal may be varied
according to the slowness with which the part of the ingot directly in contact with
the coal is to cool. In like manner the thicknesses of the aforesaid slab and of the
lateral linings may be varied according to circumstances.
When this masonry has been built up I subject this first part of the ingot mould
to a drying operation in the stove, which operation must be conducted slowly and
with the greatest care.
Before the casting I arrange the ingot mould in the pit, taking care to remove
from the slab all the sources of heat which might injuriously affect the conditions of
rapid heating. In certain cases I may use on this side still more active means, such
as currents of any fluid, for rapidly absorbing the heat developed. On the contrary
the arrangement on the side of the part built of masonry is such that the heat will
be retained as long as possible.
The metal should. be derived as far as practicable from pure raw materials, well
deoxidized by appropriate additions of manganese and should contain very little
carbon (say from 0-10 to 0.15 per cent.). The temperature for the casting should not
be too high. In these conditions I may combat the small quantity of oxides of iron
by a very small quantity of aluminium introduced into the ingot mould and the
latter is filled with a very slight effervescence. But it is requisite that no part of
the blocks of coal shall be detached and pass into the metal.

page_text: In certain cases it is advantageous to coat the outer surface of the blocks of coal
on the side where the metal will be cast with a grout of molasses mixed with clay or
other inert material; for this thin layer will prevent any kind of diffusion at the
commencement of the casting while disappearing after a certain time for enabling
the absorption to take place.
The ingot removed from the mould presents on one face a layer of coal adhering
to a layer of cast iron first very graphitous. then cleaner and cleaner, which in
turn adheres to the layer of hard steel. This face must be carefully chipped.
Next the ingot is placed in a reheating furnace and heated to the' usual
temperature for the forging. The stamp or the press acting upon the sides of the
ingot frees it very quickly from the parasitic crust, which falls as easily as ordinary
oxide.
The ingot is then treated like a homogeneous ingot and transformed into a plate
either by forging or by rolling. Next the plate is subjected to any suitable
process of tempering, for example either to a tempering with water or with oil or
even to a mixed tempering, the hard face being tempered with water and the
soft face with oil, these tempering operations being effected by immersion or by
sprinkling, according to the hardness which it is desired to obtain on each of
the faces.
Dated thie 9th dow of Anvil 1901
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements relating to the Manufacture of Armour-plates and
the like, and to Apparatus therefor.
I, VALERE EMILE LÉON DEMENGE, of 21 Boulevard Poissonnière, Paris, in
the Republic of France, 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 :-
My invention relates to the manufacture of armour plates and the like and to
apparatus therefor. It comprises a process which has for its object to effect the
decreasing cementation of armour plates, not upon the plate after the forging of
the same, but upon the ingot which will subsequently be transformed into a plate
and during the casting of the ingot; not upon the metal in the solid and hammered
state, but upon the metal prior to its solidification. I utilize the property of
carbon of being incorporated with the metal much more easily and rapidly when
the metal is liquid than when it is solid.
In the casting I obtain ingots which are very much carburated upon one face
and in which the proportion of carbon decreases with the distance from this face
and with the approach to the opposite face which is of very soft steel.
For attaining this result it is needful to combine two conditions:
(1.) To cover one of the sides of the ingot mould, that corresponding to the
face of the ingot which is to be cemented, with a sufficiently thick layer of
carburetting materials which may or may not be united by any agglomerating
agent.
(2.) To regulate the solidification of the ingot so that it will take place very
rapidly upon one of the faces of the ingot (that which is designed to absorb the
least carbon possible), next successively from this face to the opposite face (that
which has to be hardened) and then as slowly as possible on the side of this
latter face.
The curburating materials employed (pulverized wood charcoal, coke, anthracite
or the like), agglomerated by tar, molasses or other materials, such as clay, lime,

page_text: may be applied to the side of the ingot mould by any suitable means either as
pisé or in the form of blocks. Various devices may likewise be used for effecting
the rapid cooling of one of the sides of the ingot mould and for preserving its heat
at the opposite side on which the carburetting material is provided. For instance
I utilize for this purpose the differences in the conductibility of materials which
constitute the sides of the ingot mould, whose emitting powers may also be varied
as regards the outer surfaces. Moreover I take account of the conditions of
cooling by radiation and give my ingot mould the outer form which is best adapted
for obviating too rapid a cooling at the extreme parts and at the corners of the
mould.
I may also change the conditions of cooling in the various parts of the ingot
mould by causing currents of fluids at various temperatures to circulate therein.
The casting of the metal is effected in such a manner that degradations of the
carburetted side cannot take place. It is therefore needful to effect this operation
either directly by employing a special apparatus which conducts the metal without
any appreciable force to the level of the liquid and rises at the same time as this
level, or in a simpler manner as hereinafter described.
In the accompanying drawing I have represented by way of example an ingot
mould by which my invention may be carried into practice.
Figure 1 is a vertical section on the line X-Y of Figure 2, and
Figure 2 is an horizontal section on the line A-B of Figure 1.
The ingot mould is composed of two parts which are connected together at D
and E. One of the parts D F G E forms three vertical sides concave towards the
exterior, and is made of cast iron. The other part D H E constitutes a slab or
metallic plate well finished interiorly; its thickness is greater in the middle H and
it is convex towards the exterior. This part may be made either of cast iron or
steel or of an alloy of cast iron and another metal which is a better conductor
than iron, such as copper. The bottom J of the ingot mould is made of cast iron,
but it is of a certain thickness, and a prismatic incision K L M is provided therein
throughout its width so as to enable fire bricks formed with a bevel to be sunk
therein. In the middle brick is the conduit N O P for conveying the metal against
the foot of the slab of the ingot mould.
A wall QR made of blocks of carbon is sunk into masonry S T U V of fire
bricks filling the corners of the ingot mould. The blocks of carbon have a
thickness of at least 40 millimetres. The carbon employed is word charcoal,
anthracite or coke deprived of ashes as much as possible. According as it is
desired to facilitate or diminish the absorption of carbon the thickness of the
grains varies from 1 to 4 millimetres sideways. The agglomeration is obtained by
means of tar freed from its water and from its light oils, by means of molasses or
simpler with clay (10 to 15 per cent.). The blocks are subjected to a strong
compression in a very regular mould and then freed from the greatest quantity
possible of the volatile materials which they contain by any known process of
drying or distillation in a closed vessel. The process which appears to succeed
best in practice consists in heating the blocks of coal to a red heat in a closed
vessel so as to free them completely from the volatile materials which they contain.
The small faces of the blocks should be very regular, they should rest directly one
upon the other without interposition of clay grout, no scratch should be produced
at the corners, and the blocks should be strong enough to be handled without fear.
The wall consisting of blocks of coal is constructed in such a manner that the
joints cross each other; moreover each block of coal rests upon a bed of clay
covering the refractory pisé U V which lines the metallic side of the first part of
the ingot mould. The parts S T of refractory pisé must terminate in a point in
order to obtain a continuous decrease in the conductibility of the sides and the
space into which the metal is cast constitutes a rectangle.
It is easy to obtain the adherence of this pisé to the metal of the ingot mould
by providing in the interior side of the latter dove-tail grooves or by employing
any other means. . Ι may moreover consolidate it with moulder's pegs.

page_text: The thickness of the layer V U made of refractory pisé placed between the
metal of the ingot mould and the wall consisting of blocks of coal may be varied
according to the slowness with which the part of the ingot directly in contact withe
the coal is to cool. In like mauner the thicknesses of the slab D'H E and of th
lateral linings ST may be varied, according to circumstances.
When this masonry has been built up 1 subject this first part of the ingot mould.
to a drying operation in the stove, which operation must be conducted slowly and.
with the greatest care.
Before the casting I arrange the ingot mould in the pit, taking care to remove
from the slab all the sources of heat which might injuriously affect the conditions.
of rapid cooling. In certain cases I may use on this side still more active means,.
such as currents of any fluid, for rapidly absorbing the heat developed. On the
contrary the arrangement on the side of the built up part is such that the heat.
will be retained as long as possible.
The metal should be derived as far as practicable from pure raw materials, well!
deoxidized by appropriate additions of manganese and should contain very little-
carbon (say from 0.10 to 0.15 per cent.). The temperature for the casting should
not be too high. In these conditions I may combat the small quantity of oxides
of iron by a very small quantity of aluminium introduced into the ingot mould and
the latter is filled with a very slight effervescence. But it is requisite that no part
of the blocks of coal shall be detached and pass into the metal.
In cases of ingots of a great weight, it is advantageous to coat the outer surface
of the blocks of coal on the side where the metal will be cast with a grout of
molasses mixed with clay or other inert material; for this thin layer will prevent.
any kind of diffusion at the commencement of the casting while disappearing after
a certain time for enabling the absorption to take place.
The most practical process, when the carburetting side is constituted by blocks,.
consists in employing heterogeneous (non-homogeneous) or mixed blocke. The
latter may be formed by two mixtures, of carbon and clay, superposed and pressed
together, whose proportion of carbon is different, less on the surface in contact
From this results.
from the beginning with the metal, and greater at the rear.
that the delay in the cementation, brought about by the part richest in clay which
forms the front of the blocks, may be realized in two different manners.
(1.) I may give a small thickness to this retarding layer provided the proportion
of clay is augmented, leaving however sufficient carbon (about 50 per cent.) in
order that the cementation may be started from the first.
(2.) I may also augment the thickness of the retarding layer by increasing the
proportion of carbon which will still remain below that contained in the rear part
of the block.
In ordinary conditions the protecting layer may be formed of about 70 per cent..
of carbon and 30 per cent. of clay with a thickness of one centimetre, the complete
blocks having a thickness of about six centimetres and the proportion of coal of
the rear part of the blocks that designed for carburetting really being about.
85 per Cent.
The ingot removed from the mould presents on one face a layer of coal adhering
to a layer of cast iron first very graphitous, then cleaner and cleaner, which in
turn adheres to the layer of hard steel. This face must be carefully chipped..
Next the ingot is placed in a re-heating furnace and heated to the usual temperature
for the forging. The stamp or the press acting upon the sides of the ingot frees
it very quickly from the parasitic crust which falls as easily as ordinary oxide.
The ingot is then treated like a homogeneous ingot and transformed into a plato
either by forging or by rolling. Next the plate is subjected to any suitable process
of tempering, for example either to a tempering with water or with oil or even to
a mixed tempering, the hard face being tempered with water and the soft face with
oil, these tempering operations being effected by immersion or by sprinkling,
according to the hardness which it is desired to obtain on each of the faces.

page_text: 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 :-
First. The carburation of the metal in the molten state for obtaining ingots
designed for armour plates and the like, the said carburation being effected upon
only one of the faces of the ingot and decreasing with the distance from this face.
Second. In combination with the decreasing carburation of the metal, as set
forth in the first claim, a process for the progressive cooling of the ingot, the
solidification progressing in the inverse direction to that of the penetration of the
carbon, for the purpose of preventing the diffusion of the carbon through the whole
mass of the ingot, and keeping the metal in the liquid state as long as possible in
contact with the carburetting materials.
Third. In the manufacture of armour plates and the like, cemented by direct
casting in moulds with a carbonaceous side, the construction of this side by means
of blocks containing carbon and clay, in such a manner that in the vicinity of the
side which must be immediately in contact with the steel the blocks may be less
rich in carbon than in their central part, as herein before set forth.
Fourth. The employment of mixed blocks described in this Specification for
obtaining delays in the cementation variable from one part to the other of the
ingot by modifying the proportion of carbon or the thickness of the retarding
layer of these blocks from one part to the other of the sides of cementation.
Fifth. As a practical means of realizing the process for the decreasing
carburation and progressive solidification set forth in the first and second claims,
an ingot mould substantially constituted by sides of different conductibilities or
maintained at variable temperatures by any fluids.
Sixth. The construction of an ingot mould based upon the third_claim, which
consists in making the ingot mould in two parts, one of which, DHE, is made
completely of metal which the other, D F G E, receives the carburetting side, QR,
and also the different refractory linings V UST, of variable thicknesses,
substantially as and for the purpose hereinbefore set forth with reference to the
accompanying drawing.
Dated this 8th day of January 1895
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London; W.C., Agents for the Applicant.