IMPROVEMENTS IN THE MANUFACTURE OF METAL PLATES, PARTICULARLY ADAPTED FOR THE RESISTANCE OF PROJECTILES
Year: 1877

page_text: LETTERS PATENT to Alexander Browne, of the Firm of Browne and Company,
Patent Agents, of 5, Southampton Buildings, Holborn, in the County of
Middlesex, for the Invention of "IMPROVEMENTS IN THE MANUFACTURE OF
METAL PLATES, PARTICULARLY ADAPTED FOR THE RESISTANCE OF PROJECTILES."
A. communication from abroad by the "Forges Company of Chatillon and
Commentry." Paris, France.
Sealed the 12th April 1878, and dated the 16th October 1877.
PROVISIONAL SPECIFICATION left by the said Alexander Browne at the
Office of the Commissioners of Patents on the 16th October 1877.
ALEXANDER BROWNE, of the Firm of Browne and Company, Patent Agents,
of 5, Southampton Buildings, Holborn, in the County of Middlesex.
" IMPROVE-
MENTS IN THE MANUFACTURE OF METAL PLATES, PARTICULARLY ADAPTED FOR THE
RESISTANCE OF PROJECTILES." (A communication from abroad by the "Forges
Company of Chatillon and Commentry," Paris, France.)
Heretofore numerous attempts have been made with the view of increasing the
resistance of plates by forming them of layers of iron or steel of different hardness,
placed on one another; but the difficulty of connecting these layers to one another
has rendered this system not very practicable.
Attempts have been made to secure these different layers or surfaces by means of
fusion, pouring, for example, on the foundation plate the metal intended to form the
covering in fusion. The connection made by this process is of an imperfect nature
and very difficult to carry out.
:
By this Invention such part of the plate, as desired, may be hardened, and con-
sequently in a single block, without any superposition of layers, a plate being
made in front of a hard metal and at the back of soft metal, preserving at same
time all its flexibility.
To obtain this result is incorporated, either at the surface or inside the plates,

page_text: which may be of forged or rolled iron, or cast or rolled soft steel, a certain quantity
of hard cast or chilled iron or other analogous alloys, for example, those of iron,
carbon, and manganese, such as spiegel iron, the carburet alloys of iron, with
titanium, chrome, with or without manganese and the like. This incorporation is
based on the principle of the direct cementation of the iron by the melted cast iron,
or by the fusible alloys sufficiently carburetted.
The following is the manner in which the operation is effected :-Small ingots
of cast iron or alloys before indicated are introduced into apertures formed in the
plate in order to form a slight projection upon the surface to be hardened, then
being covered with a layer of earth or earthy sand in order to well preserve it from
contact with the air. This done the mass is brought to a white heat, the cast iron
or alloy forming each ingot liquifies and rapidly dissolves the parts of the plate in
contact with it for a certain thickness, varying according to the quality of alloy
employed, the duration and intensity of the heat. The projection which existed
before the fusion of the ingot allows for the contraction which takes place during
the dissolution of the iron, and the loss which, in spite of the layer of earth or sand,
always takes place. The metal which fills the enlarged cavity has thus become a
steely alloy, more or less hard, according to the quality of the cast iron or alloy
employed.
The cavities in which the ingots are placed may be arranged in different ways,
either the face desired to be hardened may be bored with holes of depths varying,
according to circumstances, in number and depth, or the surface may be bored with
a large even cavity, in which only a single ingot of cast iron or alloy is placed,
forming a slight projection; or it may be made with grooves or flanges of different
sections transversely, or across, or of any other convenient section.
The heating is effected either in a gas reverberatory furnace or in a furnace with
moveable bed on a carriage. In these the plate supplied with the cold ingots is
placed on a moveable bed, then it is covered from the bottom all round with sand
or earth in order to preserve this part from the action of the heat, and it is covered
with sand, as before explained. The carriage is introduced under the arch of a
reverberatory furnace, in order to present the upper part to the action of the heat.
The carriage is withdrawn, and consequently the plate, when it is completely or
partially cooled. If the operation takes place on the bed of a gas furnace the bed
is hollow, so as to surround the bottom of the plate up to a height bordering on
the bottom of the holes; or the plate is placed on a level bed, and surrounded at
the bottom with sand or earth, in such manner as only to expose to a white heat
the parts where the holes are. The plate being strongly heated is removed either
hot or cold; when it has become cold the coating of earth covering it is removed,
and it only remains for it to be submitted to the hardening operation in the
ordinary manner, taking advantage of its heated state for levelling its hard surface
either by the action of a hammer or by rolls.
It will be understood that the above-described process does not consist in
covering a protecting plate with a coating of steel, which has been already tried, not
altogether successfully, but on the contrary, by hardening the surface itself by
incorporating with it when cold materials which, under the influence of a high
temperature, combine with it to give it the required resistance without the other
surface of the metal losing its flexible qualities.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alexander Browne in the Great Seal Patent Office on the 16th April
1878.
ALEXANDER BROWNE, of the Firm of Brown and Company, Patent Agents,
of 5, Southampton Buildings, Holborn, in the County of Middlesex. "IMPROVE-
MENTS IN THE MANUFACTURE OF METAL PLATES, PARTICULARLY ADAPTED FOR THE
RESISTANCE OF PROJECTILES." (A communication from abroad by the Forges
Company of Chatillon and Commentry, Paris, France.)
Heretofore numerous attempts have been made with the view of increasing the
resistance of plates by forming them of layers of iron or steel of different hardness,
placed on one another; but the difficulty of connecting these layers to one another
has rendered this system not very practical.
Attempts have been made to secure these different layers or surfaces by means
of fusion; pouring, for example, on the foundation plate the metal intended to form
the covering in fusion. The connection made by this process is of an imperfect
nature and very defficult to carry out
By this Invention such part of the plate, as desired; may be hardened, and con-
sequently in a single block without any superposition of layers, a plate being made
in front of a hard metal and at the back of soft metal, preserving at same time all
its flexibility.
To obtain this result is incorporated, either at the surface or inside the plates,
which may be of forged or rolled iron, or cast or rolled soft steel, a certain quantity
of hard cast or chilled iron or other analogous alloys, for example, those of iron,
carbon, and manganese, such as spiegel iron, the carburet alloys of iron, with
tetanium, chrome, with or without manganese and the like. This incorporation is
based on the principle of the direct cementation of the iron by the melted cast iron
or by the fusible alloys sufficiently carburetted.
And in order that this Invention may be better understood, I will now proceed
to describe the same with reference to the accompanying Sheet of Drawings, in
which, at Figure 1, M shews a mass of iron or soft steel pierced with a cylindrical
or other shaped hole P, in which the cold ingot of cast iron or alloy is introduced,
the whole is then covered in with earth or earthy sand n, n, or with a cover
specially made for the purpose so as to entirely exclude the air; this done, the mass
is heated to a white heat. The ingot will rapidly melt and dissolve the plate in
contact with it for a certain thickness, varying according to the quality of the
alloy employed and the duration and intensity of the heat. If the whole is left to
cool before taking off the cover n, it will be found that all the ingot has melted in
the iron. The projection which existed before the fusion allows for the contraction
which takes place, and loss, if any, and the metal which fills the enlarged cavity
a, b, c, d, has thus become a steely alloy, more or less hard. If good cast iron is
employed, and the iron M is of the first quality, a very superior steel will be
obtained as to hardness and tenacity in the enlarged cavity a¹, b', c¹, d³, and
forming a perfect mass with the iron. Ingots of very hard cast steel, that is to
say, very much carburetted blister steel, or even cast iron, produces the same effect
of cementation during their fusion in the iron.
If it is required to harden the front of a plate it will only be necessary to form
cavities therein in juxtaposition, and fill such cavities with ingots and cover with
earth or earthy sand, as shewn in Figures 2 and 3, and treat as before. If the
cavities are placed sufficiently near to one another the whole surface will be steel,
on account of the enlargement of each cavity by the fusion of the ingot.
In Figures 4 and 5 the plate is hollowed out at that part it is desired to harden,
and the hollow is filled with one ingot of cast iron or alloy, and is heated in the
same way as before described.
Figures 6 and 7 shew gutters formed transversely or otherwise in the plate, into

page_text: which the ingots are placed and operated upon in exactly the same manner, as
before stated, and will produce the same result as when cylindrical holes are
employed. If it is required to harden the interior of the plate, holes must be pierced
alternately through the plate from the two sides thereof and at two separate
operations, as shewn at Figure 9.
The heating is effected either in a gas or reverberatory furnace, or in a furnace
with moveable bed on a carriage in which the plates, supplied with the cold ingots,
is placed on a moveable bed, then it is covered from the bottom all round with sand
or earth in order to preserve this part from the action of the heat, and it is covered
with sand as before explained. The carriage is introduced under the arch of a
reverberatory furnace, in order to present the upper part to the action of the heat.
The carriage is withdrawn and consequently the plate, when it is completely or
partially cooled. If the operation takes place on the bed of a gas furnace the bed
is hollow, so as to surround the bottom of the plate up to a height bordering on the
bottom of the holes, or the plate is placed on a level bed and surrounded at
the bottom with sand or earth in such manner as only to expose to a white heat
the parts where the holes are. The plate being strongly heated is removed either
hot or cold. When it has become cold the coating of earth covering it is removed,
and it only remains for it to be submitted to the hardening operation in the
ordinary manner, taking advantage of its heated state for leveling its hard surface
either by the action of the hammer or by rolls.
It will be understood that the above-described process does not consist in covering
a protecting plate with a coating of steel, which has already been tried, not altogether
successfully, but on the contrary, by hardening the surface itself by incorporating
with it, when cold, materials, which under the influence of a high temperature
combine with it, to give it the required resistance, without the other surface of the
metal losing its flexible qualities.
Having thus described and ascertained the nature and object of this Invention,
I declare that I claim,-
1st. The hardening of metal plates by means of direct cementation by the fusion
of cast iron or alloy, above described, in the middle and in contact with the metal
of the plates, forming a crucible, and heated from the exterior in such a way that
the fusion of the alloy takes place at the moment when that part of the plate to be
hardened is at the temperature necessary for rapid cementation.
2nd. The processes and means for the manufacture of the said plates, substantially
in the manner and for the purposes herein-before described.
In witness whereof, I, the said Alexander Browne, have hereunto set my hand
and seal, this Sixteenth day of April, in the year of our Lord One thousand
eight hundred and seventy-eight.
PRAMIZ