Improvements in the Manufacture of Steel Plates.
Year: 1895

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Steel Plates.
I, MANASSAH GLEDHILL, Director of Sir Joseph Whitworth & Co. Limited, of
Openshaw, Manchester, in the County of Lancaster, Engineer, do hereby declare
the nature of this invention to be as follows:-
My invention relates to the manufacture of steel plates, more particularly such
as those used for ship's armour and it includes the manufacture of circular plates i.e.
hoops or rings which may be developed into flat or curved armour plates or may
be used for other purposes.
Heretofore, in the manufacture of steel plates it has been customary to first cast
a thick slab block or ingot of steel and to then forge the same by a hammer or press
into a plate of the required shape and size. This method of manufacture creates, in the
finished product a very seriously defective condition which considerably impairs
its quality but the existence of which appears to have been hitherto ignored or its
importance under-estimated. This defective condition is due to the existence, in
the casting, of a central or inner portion, consisting of metal which is very inferior
in quality to that of the outer portions of the casting and which, moreover by
reason of its inner or central position in the mass of metal is nearly inaccessible to
the action or effect of the press or hammer and, therefore, remains unchanged, or
but very slightly changed, by the work done upon the slab or ingot in the forging
of the plate.
My present invention is designed to obviate this defective condition of the metal
of the forging chiefly with a view to the production of ship's armour of a quality
hitherto unattainable and it comprises a method or process of manufacture which
will ensure primarily the homogeneity of the metal throughout the entire mass no
matter what may be its dimensions and which permits the forging of the plate in
such a manner that every portion of metal during that operation will be thoroughly
and uniformly subjected to the forging impact or pressure.
My improved method or process, as carried into effect for the manufacture of
armour plates, is as follows, viz., first, the casting of a circular or cylindrical ingot;
then the removal of the central or inner inferior portion of the metal so as to leave
the ingot in the form of a hollow cylinder consisting of a sound homogeneous mass
of metal; then the enlargement of the diameter and consequent reduction of
thickness of the hoop or ring; then the cementation or carburization of the metal ;
and then the division of the hoop or ring and the forging of the divided or separate
portions into flat or curved plates of any required dimensions. The hoop or ring
may be divided in one place and opened out or it may be separated into two or more
parts or segments.
If the ultimate product is designed for other purposes than that of armour I may
dispense with the cementation or carburization of the ring or hoop previous to its
division, and in some instances, I may cement or carburize the metal after the
division of the boop or ring.
As above specified my invention comprises, as a whole, the above described
method or process of manufacturing armour plates and it comprises as one of its
products a steel boop ring or circular plate of homogeneous quality for any purpose
manufactured by first casting an ingot, then removing the central inferior portion
of the metal and then forging the hoop or ring to the required diameter and
thickness as above specified.

page_text: In the manufacture of the hoops or rings according to my invention, for any
purpose I prefer to employ a hydraulic forging press with suitable adjuncts for
supporting and adjusting the work during the forging of the same. After forging
the hoop or ring to the required dimensions, if it be intended for the manufacture
of armour I remove the scale or oxide from its surface by turning it in a lathe or
by other suitable means to facilitate the cementation or carburization of the metal.
I then place the hoop or ring in a furnace where it is subjected, at a high temperature,
to the action of the carburizing material. After the carburization and any further
forging that may be necessary it may or may not be chilled and hardened by water
or other fluid as desired.
The furnace which I prefer to use for the cementation or carburization of the
hoops or rings is circular. It is constructed in any suitable manner and lined with
fire bricks or other refractory material. The hoop or ring to be carburized, is
placed centrally within the furnace and the carbonaceous material, which is usually
applied only to the exterior circumference of the hoop, is packed tightly around the
same the interior being filled with any suitable non-carbonaceous substance. The
said furnace is provided with a suitable cover which can be conveniently removed
and replaced when required. The circular form of the furnace is very advantageous
as compared with that of other furnaces used for the cementation or carburization
of metal.
My invention for the manufacture of armour plates may be modified as follows,
viz. I take a circular block or ingot and carburize the same. Then I put the said
ingot in a press and, by forging flatten it and work it into the required dimensions
and thickness to form the armour plate which may be subsequently chilled or
hardened.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in the Manufacture of Steel Plates.
I, MANASSAH GLEDHILL, Director of Sir Joseph Whitworth & Co., Limited,
of Openshaw, Manchester, in the County of Lancaster, Engineer, do hereby declare
the nature of this invention and in what manuer 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 steel plates, more particularly such
as those used for ship's armour and it includes the manufacture of circular plates i.e.
hoops or rings which may be developed into flat or curved armour plates or plates
for other purposes.
Heretofore, in the manufacture of steel plates it has been customary to first cast
a thick slab, block, or ingot of steel and to then forge the same by a hammer
or press into a plate of the required shape and size. This method of manufacture
creates in the finished product a seriously defective condition which although its
existence appears to have been hitherto ignored or its importance under-estimated,
considerably impairs the quality of the piates. This defective condition is due to
the existence, in the casting, of a central or inner portion, consisting of metal which
is very inferior in quality to that of the outer portions of the casting. This central
portion moreover by reason of its position in the mass of metal is nearly inaccessible
to the action or effect of the press or hammer and, therefore, remains unchanged,
or but very slightly changed, by the work done upon the slab or ingot in the
forging of the plate.
My present invention is designed to obviate this defective condition of the metal
of the forging, chiefly with a view to the production of ship's armour of a quality

page_text: hitherto unattainable and it comprises a method or process of manufacture which
will ensure primarily the homogeneity of the metal throughout the entire mass, no
matter what may be its dimensions and which permits the work of forging to be
done upon the plate in such a manner that every portion of metal during that
operation will be thoroughly and uniformly subjected to the forging impact or
pressure.
My improved method or process, as carried into effect for the manufacture of
armour plates, comprises, first, the casting of a circular or cylindrical ingot; then
the removal of the central or inner inferior portion of the metal so as to leave the
ingot in the form of a hollow cylinder or hoop consisting of a sound homogeneous.
mass of metal; then the enlargement of the diameter by forging and consequent
reduction of thickness of the hoop or ring; then the cementation or carburization
of the metal; and then the division of the hoop or ring and the forming of the
divided or separate portions into flat or curved plates of any required dimensions.
The hoop or ring inay be divided in one place and opened out to form one complete
plate or it may be separated into two or more parts or segments each of which will
form a separate plate.
If the ultimate product is designed for other purposes than that of armour I may
dispense with the cementation or carburization of the ring or hoop previous to its
division, and in some instances, I may cement or carburize the metal after the
division of the hoop or ring.
In the manufacture of the hoops or rings according to my invention, for any
purpose, I prefer to employ a hydraulic forging press with suitable adjuncts for
After forging
supporting and adjusting the work during the forging of the same.
the hoop or ring to the required dimensions, if it be intended for the manufacture
of armour, I remove the scale or oxide from its surface by turning it in a lathe or
by other suitable means to facilitate the cementation or carburization of the metal.
I then place the hoop or ring in a furnace where it is subjected, at a high tempera-
ture, to the action of the carburizing material. After the carburization and any
further forging that may be necessary it may or may not be chilled and hardened
by water or other fluid as desired.
The furnace which I prefer to use for the cementation or carburization of the
hoops or rings is circular. It is constructed in any suitable manner and lined with
fire bricks or other refractory material. The hoop or ring to be carburized, is.
placed centrally within the furnace and the carbonaceous material, which is usually
applied only to the exterior circumference of the hoop, is packed tightly around
the same the interior being filled with any suitable non-carbonaceous substance..
The said furnace is provided with a suitable cover which can be conveniently
removed and replaced when required.
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 :-
1. The herein described method of manufacturing an armour plate by developing
the same from a hollow or tubular ingot of cast steel and by carburization or
cementation with or without further treatment for chilling or hardening the surface
of the metal.
2. A steel hoop or ring manufactured according to my invention in such a
manner as to be suitable for division and conversion into an armour plate or two or
more plates substantially as above set forth.
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.