Improvements relating to the Hardening or Tempering of Steel and to Apparatus therefor.
Year: 1891

page_text: Date of Application, 7th Sept., 1891
Complete Specification Left, 4th June, 1892-Accepted, 9th July, 1892
PROVISIONAL SPECIFICATION.
[Communicated from abroad by GEORGE FREDERICK SIMONDS, of Fitchburg,
Massachusetts, United States of America, Engineer.]
Improvements relating to the Hardening or Tempering of Steel and
to Apparatus therefor.
I, WILLIAM Robert 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:-
This invention relates to the hardening or tempering of steel and to apparatus
therefor.
The main object of the said invention is to provide for hardening or tempering
steel without subjecting it to undue stresses in the process of cooling, thus avoiding
fracture and warping of the metal. The quality of the steel hardened or tempered
according to the present invention is, moreover, superior in other respects to that
of steel hardened or tempered by the methods hitherto usually adopted. It is
often desirable, in hardening steel, to cool the heated metal at first with great
rapidity to ensure the proper hardening thereof, and to then complete the process
of cooling slowly so as to prevent too sudden and irregular or uneven contraction,
and consequent fracture or warping of the metal. This result has, in some
instances, been accomplished by partially cooling the metal article in a vat of
brine and then transferring the partially cooled articles through the atmosphere
into a vessel containing oil; but this method is very objectionable, as the good
effects of the process of cooling the metal first in brine and then in oil, are greatly
diminished by the interruption of the cooling process which is necessary in order to
transfer the partially cooled article from the brine to the oil.
To obviate this difficulty, the communicator of the present invention has devised
an improved method or process of hardening or tempering steel, whereby the heated.
metal may be cooled first in brine and then in oil without any interruption of the
cooling process. This method consists in first immersing the heated article in
brine, and, after it has been sufficiently cooled therein, raising the partially cooled
article from the brine into oil floating upon the surface thereof, and allowing it to
remain in the oil until it is cooled to the required temperature:
For carrying the improved method or process into effect, it is advantageous to
employ an apparatus such as that hereinafter mentioned.
One form of the improved apparatus comprises a box or vessel the interior of
which is divided into two compartments by a partition extending downward a
suitable distance from the top of the box or vessel, so as to leave free communication
between the said compartments at the lower part of the said box or vessel.
As the specific gravity of oil is less than that of brine, I am enabled, with this
apparatus, to keep the one compartment nearly full of brine, and the other compart
ment filled with brine up to a level above the bottom of the said partition and with
such a depth of oil floating upon the brine (in the latter compartment) as may be
deemed most advantageous for the purpose above mentioned. A window is provided
in the front of the latter compartment for the purpose of observing the line of
demarcation between the brine and the oil floating upon it.
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The improved method of hardening or tempering steel is carried on by means of
this apparatus as follows, that is to say :-A wire basket is first passed down through
the oil and into the brine in the compartment containing brine and oil, and is then.
moved under the said partition and allowed to rest on the bottom of the other
compartment. The articles to be hardened are then dropped into the said basket
through the brine in the latter compartment, When the articles have been cooled

page_text: to the desired degree by the brine, the basket is drawn back into the first compart-
ment and lifted up through the brine into the oil floating upon the surface thereof.
There it is allowed to remain until the articles are sufficiently cooled to complete
the process. The articles are retained in the brine and in the oil for such a length
of time as may be deemed necessary to produce the best results.
By these means, the work is accomplished without any interruption and the
following great advantages are derived, riz. :-the risk of warping and fracture of
the metal is avoided or diminished, and the quality of the metal hardened or tempered
is greatly improved as compared with that of steel hardened or tempered by the
"ordinary processes.
In another form or modification of the improved apparatus, the box or vessel,
which may be supported on suitable legs, is provided with a continuous or endless
wire apron which is carried by endless chains passed around sprocket-wheels driven
in any convenient manner. This apron travels first through the compartment
containing brine only, then under the aforesaid partition and through and out of
the other compartment, and, passing over the end of the box or vessel and then
down, travels under the said box and then up and over the other end thereof to the
point where it enters the first compartment. Suitable guards are attached to the
sides. of and across the said continuous wire apron to retain thereon the articles to
be hardened while the said apron is passing into, through and out of the said
compartments. An inclined drip-board is provided to catch the oil which drips
from the wire apron as it passes beneath the box, and also to convey this oil into
a suitable receptacle.
By means of this apparatus, I am enabled to carry on the process continuously,
by placing the articles on the apron in the compartment containing brine only, so
that they travel first through the brine, and are then raised and travel through the
oil, and fall from the apron at the end of the box into a suitable receptacle. The
articles can be left in the brine or oil for a longer or shorter period by varying
the speed of the said apron.
I do not confine myself to the use of brine and oil, as other suitable liquids for
rapidly and slowly cooling the metal may be substituted therefor in the improved
method or process. Moreover the said improved method or process may, if desired,
be carried on in any other suitable form of apparatus.
Dated this 7th day of September 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
.
COMPLETE SPECIFICATION.
Improvements relating to the Hardening or Tempering of Steel and
to Apparatus therefor.
I, WILLIAM ROBERT 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:-
My invention relates to the hardening or tempering of steel and to apparatus
therefor.
The main object of my said invention is to provide for hardening or tempering
steel without subjecting it to undue stresses in the course of cooling, thus avoiding
risk of fracture or warping of the metal.
The quality of steel hardened or tempered according to my invention is moreover
superior in many respects to that of steel hardened or tempered by any method
hitherto in use.
It is often, advisable in hardening steel to cool the heated metal suddenly at first
.and then to complete the process of cooling slowly. This course of procedure has

page_text: in some instances been carried out by first plunging the article in a vat of brine,
and after a suitable length of time has elapsed withdrawing the partially cooled
article from the brine and then transferring it through the atmosphere to a bath of
oil. This method is very objectionable owing to the interruption of the cooling
process which occurs while the article is being transferred from the brine to the
oil bath.
According to my invention I immerse the heated articles which are to be
hardened or tempered first in brine and then in oil without any pause .in, or
interruption of, the cooling process.
In order to conveniently carry my invention into practice I make use of apparatus
such as that shown in the accompanying drawings, in which :-
Figure 1 is a perspective view of a bath fitted to contain the cooling liquids.
Figure 2 is a view of a basket in which the heated articles are carried while
being cooled.
Figure 3 is a view of another bath and apparatus conveniently arranged for
automatically transferring the articles from one liquid to another and rendering the
process of hardening or tempering continuous.
Similar letters of reference denote corresponding parts in all the drawings.
A is a box or vessel the interior of which is divided into two compartments B
and C by a partition D. The said partition does not extend to the bottom of the
box or vessel, and thus permits free communication at the lower part of the said box
or vessel between the two compartments B and C. I pour in the said box A a
quantity of brine until the surface of the liquid stands at a higher level than the
lower edge of the partition D, and then into one of the compartments, say for
instance B, I pour oil which on account of its lighter specific.gravity will float on
the top of the brine. I thus so arrange that the compartment C will contain only
brine while the compartment B will contain brine up to a level above the lower
edge of the partition D and the remainder of the compartment will be filled to a
suitable depth with oil floating upon the brine. A window E is provided in the
wall of the latter compartment to enable the sharp surface of separation between
the brine and oil to be seen.
F, is a wire basket, shewn more clearly in Figure 2, for containing articles to be
cooled. F' is the handle of the said basket indicated in two positions in the. bath
Figure 1.
The operation of the apparatus is as follows, the wire basket F is passed down
through the oil in the compartment B and is then by means of its handle moved
under the partition D into the compartment C. The articles to be hardened are
now dropped into the basket through the brine and after a sufficient time has been
allowed for cooling in the brine the basket is drawn back into the compartment B
and lifted up through the brine at the bottom of the same into the oil floating on
the surface of the brine. The articles are left in this position until the process. of
hardening or tempering is completed.
In another form or modification of the apparatus shewn in Figure 3 the box or
vessel A is supported on legs G, the two compartments B and C being arranged as
before. H indicates a portion of a continuous wire apron or belt which is carried
by endless chains I. The said chains are guided by suitably arranged guide
pulleys, provided in the box A so as to pass from the compartment C under
the partition D into the compartment B, the pulleys being so arranged that the
apron is raised into that part of the compartment B which is filled with oil. The
chains pass out of the compartment B over sprocket wheels J and thence pass under
the box A being guided by wheels, and finally return over other sprocket or
guide wheels J into the compartment C. The sprocket wheels J are driven in any
convenient manner as for example by a belt K working on a pulley L fixed on the
axle of the said wheels. The apron or belt H is provided with suitable guards H¹
at the sides in order to retain thereon the articles to be hardened when the belt is
passing into, through and out of, the compartments. Moreover transverse ribs H'
are secured to the apron at intervals to prevent the articles moving about too much-

page_text: when the apron is descending or ascending. M is an inclined drip-board provided
beneath the box A to catch the oil which drips from the apron as it comes from the
compartment. B.
By means of this apparatus I am enabled to carry on the process of hardening or
- tempering articles continuously, the heated articles being placed on the apron or
belt H in the brine compartment C so as to be carried first through the brine and
then through the oil and then delivered to a suitable receptacle, at the end of the
bath. The articles may be left in the cooling liquids for a longer or shorter time
by varying the speed of the apron or belt.
It must be understood that I do not confine myself to using brine and oil in my
improved bath as it is obvious that I may use other suitable liquids of different
specific gravity for cooling the heated articles after my improved method. More-
over my said improved method of process may, if desired, be carried on in any
other similar form of apparatus.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I wish it to be understood that I do not claim the use of the
several liquids above mentioned or any suitable equivalents therefor, but I declare
that what I claim is :-
1. The process of hardening or tempering steel which consists in plunging the i
heated article into brine and then transferring it from the brine directly into oil
without intermediate exposure to the atmosphere, for the purpose specified.
2. The process of hardening articles of steel which consists in plunging such
articles into a liquid which will cool them rapidly and which is contained in a
suitable compartment, and then transferring them, whilst still submerged, into a
second liquid of less specific gravity than the first and that is capable of cooling
the articles with less rapidity, the said second liquid being contained in an adjacent
communicating compartment, and floating upon the first liquid which is contained
in both compartments, substantially as described.
3. The apparatus constructed substantially as described with reference to Figures 1
and 2 of the drawings, for the purpose specified.
4. The combination, with a box having a partition that does not extend to the
bottom thereof, of a travelling endless apron or conveyor adapted to carry the
articles to be hardened or tempered, and be guided and moved so as to pass from
one compartment of the box to the other through the opening beneath the partition,
substantially as described, and for the purpose specified.
5. The apparatus constructed substantially as described with reference to
Figure 3 of the drawings and operating as, and for the purpose, specified.
Dated this 4th day of June 1892.
•
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.