Year: 1886

page_text: [Commuincated from abroad by LA COMPAGNIE ANONYME DES FORGES DE CHATILLON
ET COMMENTRY, of Paris, in the Republic of France.]
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention to be as follows:-
Metal articles tempered according to this Invention are immersed in a bath of
molten metal as hereinafter described. In order to temper an armour plate for
example the plate is heated in a suitable furnace preferably arranged in proximity to
a chamber containing a corresponding quantity of a comparatively readily fusible
metal or alloy such as lead equal to say about three or four times the weight of the
plate. The furnace is constructed with a roof travelling upon rollers and the heated
gases from the furnace may be utilized to melt the lead in the chamber by means of a
suitable arrangement of flues and dampers. When the plate is heated to the required
extentand the bath of molten lead hasattained the requisite correspondingtemperature
say about four hundred degrees Centigrade the roof of the heating furnace is removed
and the plate hoisted out by means of a travelling crane or overhead windlass and
transferred to the bath of lead where it is wholly or partially immersed in the bath
and allowed to cool as gradually as may be considered necessary in order to avoid
unequal shrinkage and the consequent straining and injury to the plate. The plate or
other article may even be allowed to remain in the bath of lead or other metal until
the temperature is only slightly above the point at which the metal of the bath becomes
solid. Tubes for Ordnance for example may be similarly treated by suitably
modifying the construction of the heating furnace and tempering chamber preferably
in such a manner as to admit of the tube being treated in a vertical position. When
the tube is heated sufficiently a rod is passed through it from above and a bar is
passed through an eye at the lower end of the rod a similar cross bar being provided
at the upper end of the tube. The tube is then hoisted out of the heating furnace
which may be conveniently performed by means of a hydraulic press or ram arranged
at the side of the apparatus and working a chain connected to the rod. When
elevated the tube is shifted horizontally also by hydraulic power and is then lowered

page_text: into the chamber containing the molten lead or other readily fusible metal. In order
to ensure the regular descent of the tube in this chamber a chain passing round a
pulley at the bottom of the chamber is made fast to the lower end of the rod and
hauled upon by means of a hydraulic ram provided for that purpose. The chamber
containing the melted metal is preferably constructed of iron plates welded to prevent
leakage and may be heated by a special furnace having a flue which winds helically
round the chamber.
By means of this Invention bulky articles of iron or steel are enabled to be tempered
or hardened in a more effectual and uniform manner than by immersion in a bath of
water or other substance that is liquid at ordinary atmospheric temperature. The
fusible metal forming the tempering or hardening bath being a better conductor of
heat becomes quickly and uniformly heated to about the same temperature throughout
and the disadvantages attending sudden and irregular cooling are obviated. The
form of the furnace and of the chamber containing the tempering bath may be varied
to suit the nature of the articles to be treated and the temperatures of the metal to be
tempered and of the bath are regulated according to the degree of hardness or other
qualities to be imparted to the metal.
Dnted this to f Avement 1000
J. HENRY JOHNSON,
47, Lincoln's Inn Fields, London. 20
COMPLETE SPECIFICATION.
Improved Means for Tempering or Hardening Metal.
I JAMES YATE JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of this Invention which has been com-
municated to me from Abroad by La Compagnie Anonyme des Forges de Chatillon et
Commentry of Paris in the Republic of France 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 method of tempering a metal such as steel or
iron by immersion in a bath composed of some other more readily fusible metal in a
liquid condition. By means of this Invention, bulky articles of iron and steel such as
armour plates for ships or forts, tubes, breech-pieces and hoops employed in making
Ordnance, projectiles, rollers for rolling metal, axles,shafting and the like,are enabled
to be tempered with the advantages attending the use of a bath, composed of molten
metal as hereinafter described. The articles treated may be of iron or steel, of any
degree of hardness or temper being previously rolled forged or simply cast or being of
a mixed nature, resulting from any combination of the aforesaid elements or metals,

page_text: It is well known that a suitable tempering process applied to articles of wrought or
cast iron or steel, communicates, especially in the case of the latter, a more or less
marked capacity for resistance to fracture or perforation, particularly when exposed to
sudden strains, such as the blow or impact of projectiles.
Bulky articles have heretofore been tempered solely by the application of non-
metallic liquids. The employment of a metallic bath presents a double advantage.
In the first place, it ensures greater uniformity of temper, the different parts of the
surface of the article being in contact with a metal, the temperature of which may be
considered as being practically the same at its different parts owing to the great
conductivity of fluid metal as compared to a non-metallic liquid. In the second place,
the temperature of the bath may be raised to a sufficiently high degree to obviate all
danger of strain or unequal tension of the parts of the article or fracture resulting
from the tempering operation. The surfaces and angles of an article undergoing the
ordinary process of tempering, being cooled or chilled sooner than the internal parts
acquire a certain degree of rigidity which prevents a uniform shrinkage or contraction
of the metal, this being of especial importance in the case of very large or bulky
articles and is very liable to cause flaws, cracks or fractures or at any rate to prove a
source of weakness, owing to the unequal tension which results. It is even found
necessary in order to avoid danger of fracture to confine the extent to which the metal
can be safely hardened within comparatively narrow limits. With a metallic bath on
the contrary, the temperature at the surfaces and angles of the article can be main-
tained sufficiently elevated to enable the article, even when of steel, brought to a high
degree of hardness, to bear, without danger, the strains resulting from the tempering,
in its various parts and to enable the article to acquire a uniform temperature
throughout and to be subsequently cooled without producing any permanent internal
strain or tension.
The means or apparatus employed in carrying out this Invention must evidently be
modified according to the shape and dimensions of the article to be tempered, the nature
of the locality and other circumstances of the case.
And in order that the said Invention may be fully understood I shall now proceed
more particularly to describe the same and for that purpose shall refer to the several
figures on the annexed Sheets of Drawings, the same letters of reference indicating
corresponding parts in all the figures.
Figure 1 of the accompanying Drawings represents in vertical section (the section
being taken along the line 1-2,Figure3,) an apparatus arranged for tempering armour
plates according to this Invention.
Figure 2 is a corresponding plan shewing the furnace containing the bath with the
roof removed, and Figure is a horizontal section of the same, taken along the
line 3-4, Figure 1.
Figure 4 represents an elevation, seen from the side on which the hydraulic working
pistons are placed, of an apparatus for tempering tubes for Ordnance, and Figure 5 is
a side elevation of the same, partly in section.
Figure 6 is a corresponding plan, the upper part of the apparatus with the crane or
hoist used for transporting the article to or from the bath removed.
Referring to Figures 1, 2 and 3, L is a furnace, wherein the plate is heated by fires
in fire-places N, the metallic bath being contained in a furnace M. A bath of lead is
well suited for the present purpose. The temperature of this bath is regulated by
means of dampers, P and Q, (Fig. 3) which enable the whole or part of the products of
combustion from the first furnace to pass through the furnace M or to serve to shut
them off altogether. Removeable roofs, travelling on rails, enable both furnaces to
be uncovered when required for the tempering operation.
The plate being heated to a certain temperature, depending on the nature of the
metal, say, to a cherry red, or orange yellow, is transferred to the lead bath, the
temperature of the latter being also dependent on the nature and size of the plate,
the extent to which the tempering or hardening process is to be carried, and the
ultimate equilibrium of temperature, between the article and the bath, to be obtained.
In the generality of cases, the proper weight of lead to be employed is about three or

page_text: four times that of the plate or article to be tempered and the initial temperature of the
bath is about four hundred degrees centigrade. The total or partial immersion of the
plate is obtained by weighting it or by any other convenient means. In some cases,
the plate requires to be tempered at a part ouly of its thickness. The plate is not to
be taken out of the bath until the temperature of every part of it is considered to be
the same as that of the bath and the removal of the plate may even be postponed
until its temperature has descended to a degree only slightly above that at which the
bath solidifies.
In the apparatus for tempering tubes for ordnance illustrated in Figures 45 and 6
the arrangements are modified as next hereinafter described. A (Figures 5 and 6) is
a vertical furnace with the fire plates C arranged one above the other to obtain a
uniform heating of the tube. B is a tank containing the metallic bath and made with
welded or soldered joints to prevent leakage of the liquid. This tank is heated
externally by means of a fireplace D the flame from which winds around the tank in
the form of a helix. On the bottom of the tank there is fixed a pulley I over which
is passed a chain J shown by a fine line in the drawing which serves to ensure the
proper immersion of the tube. This chain is connected to a piston working in a
hydraulic cylinder F, Figures 4 and 6.
The tube is lifted by means of a travelling hoist K on a raised frame or bridge H.
The lifting chain is worked by a hydraulic cylinder E the piston of which is connected
to a series of pulleys arranged for accelerating the motion. The traversing movement
of the hoist is obtained by means of a third hydraulic cylinder G the piston of which
is connected to a rack R acting on a small windlass S having a drum on which a
chain T is wound and produces the required motion of the hoist.
In order to temper a tube it is first heated to a suitable temperature in the heating
furnace and a rod V Figure 5 is passed through the tube in such a manner as to
enable a transverse pin to be passed through an aperture R and inserted in a
hole in the lower end of the rod. The rod is then drawn upwards until the said
transverse pin bears against the lower end of the tube and a similar pin is passed
through the rod at the upper end of the tube.
When the tube has been lifted out of the heating furnace by the travelling hoist
it is placed in a vertical position over the tempering tank B containing the bath of
fluid metal heated to the proper temperature. The chain J is then attached to the
rod U and the tube is lowered and drawn down into the tank B where it is allowed to
remain for such period as may be considered necessary.
It is evident that the means or mechanical arrangements or apparatus may be
modified according to the nature of the work without affecting the principle of the
Invention.
Having now particularly described and ascertained the nature of the said Invention
and in what manner the same is to be performed I declare that what I claim is:-
First. Tempering or hardening armour plates, tubes for ordnance and other like
articles of iron or steel by immersion in a metallic bath substantially as hereinbefore
described.
Second. Tempering or hardening armour plates or tubes for ordnance or the like
by immersion in a metallic bath with the emplovment of apparatus arranged and
operating substantially as herein before described with reference to Figures 1, 2 and 3
or 4, 5 and 6 of the accompanying drawings.
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