An Improved Manufacture of Armour Plates and Apparatus therefor.
Year: 1893

page_text: Date of Application, 16th Dec., 1893
Complete Specification Left, 15th Oct., 1894-Accepted, 24th Nov., 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE HARVEY STEEL CO., of 52, Wall Street,
New York, United States of. America.]
An Improved Manufacture of Armour Plates and Apparatus
therefor.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows :-
1
This invention relates to an improved manufacture of armour plates and
apparatus therefor. The chief feature of the said invention is the utilization of
the initial heat in an ingot directly after being cast for the generation of a gas
which will effect the carburization of said ingot. Said ingot is subsequently
forged and rolled in the well known manner for the production of an armour
plate.
.
In carrying the said invention into practice the metal is cast in an iron or
sand mould, one side of which is formed by a slab composed of a carbonaceous
mixture, or by a mass of finely divided carbon tightly packed and preferably held
in place by a thin screen, say, for example, light netting or very thin sheet iron.
The metal on being poured from the ladle into the mould will rise gradually up the
side of the aforesaid slab and the sides of the mould, and that side of the ingot
next the carbon will, while at a high temperature, generate gases, which will
penetrate the face of the ingot and decrementally carburize the same to a greater
or less depth. Such carburization will be governed by the pature of the carbon
used, that is to say, whether it is of. a refractory nature or not.
For instance, if plumbago be used, the carburization would be simply superficial.
While if coke dust be used, the carburization would extend throughout the ingot.
It is thus obvious that the depth of carburization can be governed as required.
The metal to be treated may be a steel containing from 5/100 of one per cent.,
to 5/10 of one per cent. of carbon, or even iron may be treated by this process. In
regard to the mixture of carbon to be placed in the side of the mould; this must
be varied according to the result desired. For instance, if superficial carburization
be desired, plumbago may be used tightly packed, being a carbon of a very
refractory nature. Or, if deep.carburization is desired, coke dust may be used
tightly packed, as heretofore indicated.
Plates composed of mixtures of carbons baked in a crucible kiln may be used
with considerable success. The mixture of carbons in these plates is varied as
required to properly govern the decremental carburization in the ingot.
After the ingot has been cast against the carbon plate, it will be allowed to remain
in the mould, say, until black hot, (care being taken of course after the ingot is
cast, to cover the top of the mould with sand, so as to confine all gases which may
be generated by the contact of the metal with the carbonaceous mass). The ingot
after being allowed to. cool will then be taken from the mould, beated for the
rolling mill, and afterwards manipulated by the usual methods for forging or
rolling, and lastly, heated and tempered. The hardening can be done either
with oil or water or by a process combining both. The ingots may be carburized
to a depth of one-third of their, thickness more or less, the percentage and depth of

page_text: carburization being governed by varying the carbonaceous mixture and the length
of treatment.
Dated this 16th day of December 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improved Manufacture of Armour Plates and Apparatus
therefor.
I, HENRY HARRIS LAKE, of the Firm of Haseltine, Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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:-
This invention relates to an improved manufacture of armour plates and
apparatus therefor. The chief feature of the said invention is the utilization of
the initial heat in an ingot cast in a mould, for the generation of gas which will
effect the decremental carburization of such ingot in the mould. The said ingot is
subsequently forged and rolled in the well known manner to the required
dimensions and thus I produce an armour plate which will be decrementally
carburized, that is to say, the face of the plate will be highly carburized and
the proportion of carbon will gradually diminish from the face inwards, or toward
the back of the plate.
In carrying the said invention into practice the metal is cast in an iron or sand
mould, one side of which is formed by a slab composed of carbon or a carbonaceous
mixture, or by a mass of finely divided carbon tightly packed and preferably held
in place by a thin screen, consisting for example of light netting of metal or other
suitable material, or of very thin sheet iron. The molten metal on being poured
from the ladle into the mould will rise gradually up the side of the aforesaid slab
or carbonaceous mass and the sides of the mould, and by contact with the carbon
will generate gases which will penetrate the face of the ingot and decrementally
carburize the same to a greater or less depth. Such carburization will vary in
respect of its extent and degree according to the condition or quality of the carbon
used, that is to say, according to its refractoriness; the particular form or kind of
carbon or mixture of carbon used will therefore be varied according to the result
desired. For instance, to produce superficial carburization tightly packed plumbago,
which is very refractory, may be used, while if deep carburization is desired coal
dust, tightly packed will serve the purpose.
Slabs composed of mixtures of carbon baked in a crucible kiln may be successfully
used. The mixture of carbons in these plates is varied as required to properly
govern the decremental carburization of the ingot.
The metal to be treated may be steel containing from 5/100 of one per cent.
to 5/10 of one per cent. of carbon, or iron may be treated by this process for the
purpose specified.
After the ingot has been cast in contact with the carbon slab or carbon mixture,
it will be allowed to remain and cool in the mould, say, until black hot, care being
taken of course after the ingot is cast, to cover the top of the mould with sand, so
as to confine all gases which may be generated by the contact of the metal with
the carbonaceous slab or mass. The ingot after being allowed to cool as aforesaid
will then be taken from the mould, heated for the rolling mill, and afterwards
manipulated, by the usual methods of forging or rolling, and lastly, it is heated and
tempered. The hardening can be effected either with oil or water or by a process
wherein both oil and water are used. The ingot may be carburized to a depth of
one-third of its thickness more or less, the percentage and depth of carburization

page_text: being governed as before stated by varying the carbonaceous mixture and also by
varying the duration of the treatment.
By way of example I may instance an ingot containing twenty five one hundredths
(25/100) per cent. of carbon and thirty (30) inches thick. The carburization will
then be about as follows: viz. from the face to a depth of one inch, one and two
tenths (12/10) per cent. of carbon; for the next inch, one (1) per cent. of carbon ;
for the next inch ninety five oue hundredths (95/100) per cent. of carbon; for the
next inch nine tenths (9/10) per cent. of carbon; for the next inch, eighty five
one hundredths (85/100) per cent. of carbon, and so on.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
1. In the manufacture of an armour plate, the method of carburizing which
consists in casting an ingot, in an iron or other mould one side of which is a slab
of carbon or a mass or layer of finely divided and tightly packed carbon, or
carbonaceous material, substantially as, and for the purpose, specified.
2. An ingot which has been decrementally carburized by the method herein
described, for the purpose specified.
3. An armour plate made, by the usual methods of forging or rolling and
hardening, from an ingot of the kind referred to in the preceding claim.
4. The mould, having one side formed by a slab of carbon or carbonaceous
material or by carbon finely divided and tightly packed, substantially as, and for
the purpose specified
Dated this 10th day of October 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.