Improvements in and connected with the Processes of Hardening and Tempering Steel Wire.
Year: 1892

page_text: Date of Application, 15th Dec., 1892
Complete Specification Left, 15th Sept., 1893-Accepted, 21st Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in and connected with the Processes of Hardening
and Tempering Steel Wire.
I, JOSEPH MOSELEY of the Chapelfield Works, Ardwick, Manchester in the
County of Lancaster, Manufacturer, do hereby declare the nature of this invention
to be as follows:-
In carrying out the existing processes for hardening and tempering steel wire,
various defects disadvantages and inconveniences are experienced which it is the
object of this invention to avoid. For example, it is difficult to determine and
control the temperatures employed, and the results are consequently uncertain or
irregular. Owing to the large amount of surface as compared with the mass,
particularly in thin wires, the amount of radiation is very large, and a dispro-
portionate amount of heat has to be employed to compensate for this radiation.
Also, the heat having to be applied generally from a greater or less distance from
the wire, a loss arises from this cause, whilst the wire having to travel some distance,
however small, from the point at which it experiences its maximum temperature to
the bath, it follows that the wire must be heated to a higher point than is absolutely
necessary under perfect conditions. There are other disadvantages and incon-
veniences attending the ordinary methods of hardening and tempering steel wire,
which are also obviated by my invention as will be apparent from the description
of its nature hereinafter given.
According to this invention I heat the wires to be hardened or tempered by
means of electricity and quench or cool them in a suitable bath at the instant they
attain the exact degree of temperature required. The electric current used as the
source of heat is conducted through the wire itself and the heat is developed by the
resistance of the wire to the passage of the current.
I am quite aware that a direct current of electricity has already been proposed
and attempted to be used for the purposes of this invention, but hitherto no success
has been obtained principally because the large proportion of surface relatively to
the mass of the wire produces such an amount of radiation that the wire cannot be
brought to the required temperature without the use of a dangerous density of
current. The essential feature of my invention is the application of means to
prevent or diminish this radiation of heat from the wire.
For this purpose I arrange to lead the heated wire (or the wire through which
the current is passing) into the bath through some suitable non-conductor of heat.
As a simple example of the means which I may employ for the purpose of my
invention I may take a glass tube of say one-centimeter in diameter more or less
according to the thickness of the wire operated on, and (say) twenty-five centi-
meters long. This tube is arranged vertically with its lower end just immersed in
the hardening or tempering bath. The wire is led through this tube into the bath
at a speed determined by the density of the current and the diameter and nature of
the wire.
Current is led into the wire before it reaches the tube and may be led
out of the wire in or after it leaves the bath. The enclosed air in the tube acts as
an insulator to prevent the radiation of heat, and the transparency of the tube
permits the observation of the temperature of the wire. Although it is advantageous
to use a glass tube, I do not limit myself to this material, nor do I limit myself to
the use of a tube since the wire may as readily be passed through any suitable heat
insulator.
With this arrangement the wire will gradually increase in temperature from the·

page_text: upper part of the tube to the moment of its passage into the bath, when it is at its
maximum.
The temperature at which the wire enters the bath may be controlled by one or
both of two methods, that is to say by running it at a greater or less speed, or by
passing a current of greater or less density through it. As both of these methods
are under easy and absolute control, it follows that the temperature can be governed
with the greatest degree of nicety.
From the nature of the processes employed it is obvious that no scale or oxidation
will be produced on the wire.
Dated this 14th day of December A.D. 1892.
WILLIAM E. HEYS,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and connected with the Processes of Hardening
and Tempering Steel Wire.
I, JOSEPH MOSELEY of the Chapelfield Works, Ardwick, Manchester, in the
County of Lancaster, Manufacturer, 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 :-
In carrying out the existing processes of hardening and tempering steel wire,
various defects disadvantages and inconveniences are experienced which it is the
, object of this invention to avoid. For example, it is difficult to determine and
control the temperatures employed, and the results are consequently uncertain and
irregular. Owing to the large amount of surface as compared with the mass,
particularly in thin wires, the amount of radiation is very large, and a dispro-
portionate amount of heat has to be employed to compensate for this radiation.
Also, the heat having to be applied generally from a greater or less distance from
the wire, a loss arises from this cause, whilst the wire, having to travel. some
distance, however small, from the point at which it arrives at its maximum tem-
perature, to the bath, it follows that since in travelling this distance it must lose
some of its heat, the wire must be heated to a higher point than is absolutely
necessary under perfect conditions. I do not only avoid these disadvantages and
inconveniences by my present invention, but others also as will be obvious from the
description hereinafter given.
According to this invention I heat the wires to be hardened or tempered by means
of electricity and quench or cool them in a suitable bath at the instant that they
attain the degree of heat required. The electric current is conducted through the
wire itself and the heating effect is produced by the resistance of the wire to the
passage of the current.
I am quite aware that it has already been proposed and attempted to use, in a
different manner and by different means, a direct current of electricity for heating
and tempering wire, but so far without success. This want of success may be owing
to the fact that the wire whilst being heated was freely exposed to the air. The
essential feature in my invention is the application of means for preventing free
access of air to the electrically heated wire, which means also may be utilised to
prevent radiation of heat therefrom.
For this purpose, I arrange to lead the wire, whilst the current is still passing
through it, into the bath, through a sufficiently enclosed space chamber or passage
to which free access of air is prevented, and which may also be constructed of or
contain some suitable non-conductor of heat. The wire is caused to travel through
the enclosed space so long as the current is traversing it, and the degree of hardness
or temper may be governed either by the speed of travel, or by the density of
current or by both combined.

page_text: I may carry out my invention in various ways and by various means, but that
which have hitherto found to be the best, I will now describe by the aid of the
accompanying diagram and by way of example.
A tube, preferably of glass, may be employed to enclose the wire just before its
passage into the bath, and whilst the current is passing through it. As indicated
in the diagram A is the hardening or tempering bath; contained in a suitable tank
or vessel B and C is the glass tube.
The precise dimensions of the tube are not of great moment provided it be of
sufficient diameter to prevent its being cracked by the heat of the wire and to
prevent possibility of constant contact, and of sufficient length to enclose the whole
of the highly heated part of the wire. For fine wires a diameter of about one
centimetre and a length of about twenty-five centimetres will suffice. For the
thicker wires, larger tubes should be used.
The wire is led through this tube into the bath at a constant speed determined
by the density of the current and the degree of hardness or temper desired. Or
conversely, the density of the current may be determined by the speed and the
hardness or temper sought.
The principal advantage attending the use of a glass tube is that it permits
constant optical observation of the temperature colour of the wire. It is not
necessary to close either end of the tube, as, if the tube be of sufficient length the
air is sufficiently excluded, particularly if the lower end of the tube be immersed
in the bath as I in all cases prefer. If any considerable distance exists between
the end of the tube and the bath, not only does the wire become oxidised but in
some cases actually burnt through. If the end of the tube he actually immersed in
the bath, the best condition exists, because the wire enters the bath at the maximum
temperature attained by it, and there is no loss of heat by needless exposure, nor is
there any oxidation produced on its surface, nor addition of carbon possible.
In substitution for the tube there may be used any enclosed space filled with
inert fluid. Alternatively the wire may be similarly passed through a hole formed
in a mass or block of heat resisting material or so in any case that the air cannot
freely act on the wire just before it passes into the bath, or whilst it is at a
temperature above visible red or thereabouts.
Below the tube C there is arranged in the bath a guide pulley D, and above the
tube, a second guide pulley E. At the opposite end of the bath there may be a
third guide pulley F, over which the wire is drawn out of the bath. All these
guide pulleys are grooved, and should be of such a diameter that the wire is not
permanently curved by passing around them. The wire passes over the pulley E,
down through the tube, under the pulley D, and over F.
Windicates the wire which is being operated on. The current should be led
into the wire before it reaches the upper end of the tube C, and this may con-
veniently be done by connecting the metallic pulley E to one of the poles of the
dynamo or battery and ensuring perfect metallic contact with the wire by wire
brushes or the like. The current may generally be led out from the metallic
pulley D, and the density of the current and the speed of the wire may be so
regulated with this arrangement that almost any required degree of temper or
hardness may be obtained. If desired however, the current may be led out of the
wire from the metallic pulley F, or by means of brushes or a rubber at any point
such as from the adjustable pulley G, between D and F. Thus, instead of hardening
and tempering in two consecutive operations the wire may be completely tempered
at one passage.
Between the source of current and the point at which the contact is made with
the wire W, there should be intercalated a set of variable resistances by means of
which the density of current in the wire may be controlled.
Although have indicated the apparatus in the drawings and have herein
described it as having only one wire passing through it at the same time, it will be
obvious that a greater number may be so passed simultaneously and separately.

page_text: 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 method of hardening and tempering wire which consists essentially in
conveying the wire continuously through an enclosed space from which oxygen is
practically excluded and thence through a bath, the wire during its passage through
the enclosed space being heated to the required degree by an electric current
passing through it, substantially as hereinbefore described.
2. In the process of hardening and tempering wire set forth in the preceding
claiming clause, passing a current of electricity through the wire during its passage
through an enclosed space from which oxygen and sources of oxygen is or are
practically excluded, substantially as and for the purpose hereinbefore described.
3. In the process of hardening and tempering wires set forth in the first claiming
clause, constituting the enclosed space by means of a glass or similar tube,
substantially as and for the purpose hereinbefore described.
4. An apparatus for hardening and tempering wire, constructed arranged and
operated substantially as hereinbefore described and as illustrated by the accom-
panying drawings.
Dated this 14th day of September A.D. 1893.
WILLIAM E. HEYS,
Agent for the Applicant.