AN IMPROVED PROCESS FOR TEMPERING AND FORMING ARTICLES OF STEEL OR STEEL AND IRON, AND IN APPARATUS CONNECTED THEREWITH
Year: 1874

page_text: PROVISIONAL SPECIFICATION left by George Frederic Simonds and
James Augustus Ferson at the Office of the Commissioners of
Patents, with their Petition, on the 17th June 1874.
We, GEORGE FREDERIC SIMONDS and JAMES AUGUSTUS FERSON, both
of Fitchburg, in the State of Massachusetts, one of the United States
of America, Machinists, do hereby declare the nature of the said.
Invention for "AN IMPROVED PROCESS FOR TEMPERING AND FORMING ARTICLES
OF STEEL OR STEEL AND IRON, AND IN APPARATUS CONNECTED THEREWITH,”
be as follows:
" to
Our Invention relates to the hardening, tempering, and bringing to
their ultimate form articles of steel, or of steel combined with iron, and
it consists,-
First. In the process as herein-after described.
And, Second. In the construction and arrangement of the tempering
oven necessary to carry out the process and insure success.

page_text: i
In our process we heat the articles to be treated in the usual manner,
and after hardening we again heat for tempering and forming. When
at a proper heat we compress the metal in a clamp, in which the
opposite compressing surfaces are either straight or shaped to suit the
form required in the article to be produced. Up to this point our
process is common and well known, the same having been practised in
efforts heretofore made to temper and straighten saws after hardening:
It is well known in mechanical and manufacturing circles that all such
efforts have heretofore proven unsuccessful, or only partially successful,
and saws when taken from the clamps have required hammering to a
greater or less extent, thus adding materially to the cost of the article
produced.
The object of our Invention is to overcome the difficulty heretofore
experienced, and to accomplish this we have ascertained by a long
course of experiments in what the difficulty lies, and hercin consists
essentially our Invention.
During the tempering process we found it was necessary to avail
ourselves of the greatest ultimate heat allowable in producing a steel
temper, and having reached this point we maintain the heat and com-
pression a sufficient time, say about thirty minutes, more or less, to
allow the particles of metal to assume a proper relation to each other,
and the article to take permanently the form of the clamping surfaces.
Another condition of success is a perfect evenness of heat from the
time. our new part of the process begins until it ends.
The proper degree of heat as well as its required regularity may be
easily determined in a dark room, where the clamps will show the same
regular dark red colour throughout, any irregularity of heat readily
showing itself; or it may be determined by simply sprinkling sawdust
over the entire clamp, in which case if the sawdust burns with a quick
bright sparkle over the entire surface it shows that the proper tempe-
rature is attained, and the article after a proper lapse of time may be
safely removed from the clamps without fear of its twisting or warping.
The second part of our Invention relates to the construction of the
oven necessary to secure the perfect evenness of temperature necessary
to secure success in the above process.

page_text: In tempering ovens heretofore made the clamps or dies have been
placed in direct contact with the flame from the fire, where it is found
impossible to produce that evenness of heat necessary.
The object of this part of our Invention is to avoid any contact of our
clamps with the fire, and only allow them to receive the heat after it
has been evenly dispersed, thereby securing a uniformity of heat
throughout the clamps and the article to be treated.
Air
In constructing our improved tempering oven we arrange in the front
wall thercof a suitable door. for the introduction of the articles to bo
tempered and formed: In the top are openings, usually four in number,
to allow the heat to pass off and to produce a draft when the smoke fluc
is closed. In the bottom are openings to allow the heat to distribute
itself evenly through the oven and surround the clamps, which compress
the article to be tempered and formed. Immediately over the fire-box
we place a heavy fire-proof tile, extending slightly over the sides of the
fire-place, so as to catch and arrest the direct heat from the flame.
passages are left on each side of this tile.
it and the arch of the fire-box a hot-air
the air passages lead. Above this hot-air chamber and leading through.
the masonry to the tempering oven are the radiating flụcs, which again
distribute and equalize the heat before it reaches the perforated bottom
of the oven. This bottom in turn becomes heated throughout its extent,
and materially aids in producing that evenness of temperature within
the oven which is absolutely necessary to secure success.
Above the tile and between
chamber is formed, into which
The perforations in the bottom may be closed when it is desired to
shut off the gas from the article being treated, for instance, when it is
desired to determine the condition of the article being treated by its
colour.
When the article to be treated has been properly hardened it is placed
between the clamps, and there secured by any convenient means. We
prefer however to use wedges, which are driven into the slotted.rod.
The clamps may rest within the oven and be operated by the rod, or
they may be constructed separate therefrom. In the latter case. the
article to be treated is properly compressed between the clamps, and
the clamps then secured, after which they are passed into the oven, the
form of the clamp allowing a free contact with the heat.

page_text: To straighten articles that are out of the required form that do not
require to be rehardened, like circular saws for instance, which have
been warped or blistered in use, we put them between the clamps and
treat as before described.
The process is also applicable to articles which are left sufficiently