Year: 1887

page_text: Date of Application, 12th Sept., 1887
Complete Left, 11th June, 1888
Complete Accepted, 20th July, 1888
I, TOLMIE JOHN TRESIDDER, of the Atlas Steel and Iron Works, Sheffield, in the
County of York, Captain in H.M. Corps of Royal Engineers, do hereby declare the
nature of this invention to be as follows:-
Metal articles hardened according to this invention are placed in or have applied to
them while they are at a high temperature a stream of air or other gas. The amount
of hardness to be imparted is regulated either by the temperature of the stream of
air or other gas or by the duration of the exposure to such stream or by both
combined. Or where unequal hardness is desired parts only of the metal article may
be thus treated.
By means of this invention metal articles can with sufficient rapidity to produce the
hardening effect be lowered in temperature to any required degree, which is not the
case with baths of water oil or molten metal or any other process at present or previously
in use.
*CARPMAEL & Co.,
Agents for the Applicant.

page_text: Improved means for Hardening metal.
I, TOLMIE JOHN TRESIDDER, of the Atlas Steel and Iron Works, Sheffield, in the
County of York, late Captain in H.M. Corps of Royal Engineers, 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 :-
According to this invention articles of steel or other metal capable of being hardened
are while they are at a high temperature submitted to the action of thin uniform
layers of air or other gas or vapour made to travel rapidly over their surfaces.
The amount of hardness to be imparted is regulated either by the temperature or
speed of the stream or by the amount of moisture contained in it or by the duration of
exposure to such stream or by a combination of these means.
Where unequal hardness is desired parts only of the metal article may be thus
treated.
The following is the way in which 1 prefer to carry out the invention.
I cause the heated metal article to be placed into a tuyero or passage of such
a form that a narrow space is loft all around it between it and the inner surface of
the passage walls and I cause a rapid stream of air gas or vapour to travel through
the passage. I make provision for using either hot or cold air at will or for charging
the air more or less with moisture. Preferably I employ air carrying watery vapour
along with it but dry air or steam alone may be used.
Figure 1 of the drawing annexed is a longitudinal section of the apparatus I
employ and Figuro 2 is a plan view with the cover removed of the passage or
tuyere into which the heated metal article is to be placed.
In these figures A is a stop valve on a pipe communicating through stop valves
with the delivery pipes of two blowing engines, of which one delivers a hot and
the other a cold blast. B is a chamber, preferably of metal, in which porous pipes C
are arranged as in a multitubular boiler.
By a small pipe D at the top of this chamber, water under pressure can be admitted
to it which water will percolate slowly and in a fine state of division into the interior
of the pororous pipes and be there evaporated and absorbed by the air that is passing
through them.
To the further end of the same chamber is attached a tuyère or passage E into which
the object under treatment is to be placed. The form of this tuyère will vary with that
of the article being operated on; but the principle of the process, which is that of
causing a thin layer of air or aqueous vapour in rapid motion to pass uniformly over
the surfaces of the object remains unchanged.
F are pressure gauges to record the pressure of blast. G is a cold water inlet tap.
Ha cold water outlet tap. I a thermometer for recording the temperature of the
blast. J is a "knife edge" to divide the blast and to conduct it to the surfaces of the

page_text: article. K is a rectangular steel slab under treatment. L is a swing bolt to retain
the slab in its place against the pressure of the blast. M are centreing screws or studs
adjusted beforehand to maintain the spaces for the blast around the slab.
The process can be used generally for hardening all articles of simple shapes
(such as shafts, axles, projectiles, gun tubes, armour plates, etc.). In the drawing
I have shown it as being applied to a rectangular slab of steel.
The means shown for imparting moisture to the air blast are well suited for the
purpose but other means may be employed as for example it may be effected by
admitting to it a jet of steam from a steam boiler under high pressure or steam from
such a source may be used alone without air.
The apparatus is used in the following manner-
The slab having been gradually heated in a furnace to such temperature as would
just suffice to make it quite hard if quenched in water, is quickly placed and fixed in
the tuyere or passage E, the lid of this passage is then closed and the blast is turned
on. The temperature of the slab will now begin to fall rapidly and with great
uniformity till it becomes the same as that of the blast, and this fatter is to be regulated
according to the effect it is desired to produce on the steel, as for example
(a) by using a blast of a high temperature at first and allowing it to become cold
by slow degrees, there will be comparatively little hardening of the steel but mainly
an improvement in its molecular structure.
(b) by using the cold blast only and keeping the chamber B full of water from the
commencement of the operation, the blast will consist of a cold aqueous vapour or fog,
and the steel will become intensely hard. The water may, if required be artificially
cooled, but the cooling produced by the rapid evaporation will generally suffice.
(c) by intermediate methods of manipulation between (a) and (b) intermediate
results may be obtained or they may be obtained by varying the amount of moisture
imparted to the blast.
The compressed air may be brought directly from the fans or compressing machinery
and be cooled in the manner described by causing it to evaporate water or may be
otherwise cooled before bringing it into contact with the heated metal.
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. Hardening steel or other metals capable of being hardened by submitting them
when at a high temperature to the action of thin streams of air or other gas or vapour
made to travel rapidly over their surfaces.
2. Hardening steel or other metals capable of being hardened by submitting them
when at a high temperature to the action of thin streams of air charged with
moisture.
3. The combination for this purpose of the chamber and porous tubes as described
for cooling and wetting the air before applying it.
DL
11/1 1
CT
1000
T. J. TRESIDDER.