IMPROVEMENTS IN DECARBONIZING OR ANNEALING AND SOFTENING PORTIONS OF ARTICLES MANUFACTURED OF STEEL IRON OR OTHER METAL."
Year: 1877

page_text: LETTERS PATENT to Robert Hadfield, of Sheffield, in the County of York,
Steel Manufacturer, for the Invention of "IMPROVEMENTS IN DECARBONIZING
OR ANNEALING AND SOFTENING PORTIONS OF ARTICLES MANUFACTURED OF
STEEL IRON OR OTHER METAL."
PROVISIONAL SPECIFICATION left by the said Robert Hadfield at the Office
of the Commissioners of Patents on the 19th October 1877.
ROBERT HADFIELD, of Sheffield, in the County of York, Steel Manufacturer.
"IMPROVEMENTS IN DECARBONISING OR ANNEALING AND 'SOFTENING PORTIONS of
ARTICLES MANUFACTURED OF STEEL, IRON, OR OTHER METAL."
This Invention has for its object the overcoming the many difficulties and
uncertainty heretofore experienced in hardening parts of articles, either large or
small, manufactured from steel, iron, or other metal, either wrought or cast.
Hitherto in order to obtain this object it has been customary to first make the
articles themselves soft, and afterwards to temper such portion as is required to
be hard by first re-heating the same, and then quenching it in water, oil, or other-
wise; but owing to the uncertainty of the result all such methods have proved
extremely unsatisfactory.
Now in my improved process I reverse this order of procedure by first making
or casting the article throughout of as hard a temper as it is desired; the hardened
portions thereof shall ultimately remain. I then subject such parts of the article
manufactured as require to be softened to an annealing or decarbonising process,
whereby I am enabled to reduce the carbon contained therein to any desired ratio,
and thus not only to soften such portions of the article as may be requisite, but
also to graduate such softness in any desired degree.. In order to effect this I
subject such parts of the article as are desired to retain their primary degree of
hardness to a blast of extremely cold air, which is generated and conveyed thereto
Price Ad I

page_text: by any suitable means and apparatus; or preferably I subject such parts to
immersion in a current of intensely cold water, constantly circulating around them,
at the same time that I expose the other parts requiring to be softened to such a
degree of heat as is necessary for annealing or decarbonising them to any desired
ratio. I take care to keep such parts of the articles as require to be hard,
immersed in cold water, while the other portions remain exposed to the action of
the fire.
My improved process is particularly applicable to the manufacture of steel shell
or shot intended to pierce armour plates and other similar defences, & also for
anvils, rolls for rolling mill purposes, faces for steam hammers, and inany other
purposes, but especially it is particularly adapted for the taper or graduated
hardening of shells and other projectiles.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Hadfield in the Great Seal Patent Office on the 18th April
1878.
ROBERT HADFIELD, of Sheffield, in the County of York, Steel Manufacturer.
"IMPROVEMENTS IN DECARBONIZING OR ANNEALING AND SOFTENING PORTIONS OF
ARTICLES MANUFACTURED OF STEEL, IRON, OR OTHER METAL."
This Invention has for its object the overcoming the difficulty and uncertainty
hitherto experienced in hardening parts of articles, either large or small, manu-
factured from steel, iron, or other metal, either wrought or cast.
Hitherto in order to attain this object it has been customary to first make such
articles soft, and afterwards to temper such portions thereof as are required to be
hardened by first re-heating the same, and then quenching them in water, oil, or
otherwise; but owing to the uncertainty of the result all such methods have proved
extremely unsatisfactory.
Now in my improved process I reverse this order of procedure by first making or
casting the article throughout of as hard a temper as it is desired; the hardest
portions thereof should ultimately remain. I then subject such parts of the article
as require to be softened to an annealing or decarbonizing process, whereby I am
enabled to reduce the carbon contained therein to any desired ratio, and thus not
only to soften such portions of the article as may be requisite, but also to graduate
such softness in any desired degree. In order to effect this I subject such parts of
the article as are desired to retain their primary degree of hardness to a blast of
extremely cold air, which is generated and conveyed thereto by any suitable means
and apparatus; or preferably I subject such parts to immersion in a current of
intensely cold water, constantly flowing in and circulating around them, and
afterwards running away, at the same time that I expose the other portions
requiring to be softened to such a degree of heat as is necessary for annealing or
decarbonizing them to any desired ratio. I take care to keep such parts of the
articles as are required to remain hard, immersed in cold water, while the other
portions remain exposed to the action of the fire.

page_text: My improved process is particularly applicable to the manufacture of steel shell
or shot intended to pierce armour plates and other similar defences, and also for
anvils, rolls for rolling mill purposes, faces for steam hammers, and many other
purposes, but especially it is particularly adapted for the taper or graduated
hardening of shells and other projectiles.
Having now described and ascertained the nature of my said Invention and the
manner of carrying the same into effect, I would have it understood that I claim
the improved method of decarbonizing or annealing and softening portions of
articles manufactured of steel, iron, or other metal, thereby reducing the carbon
contained therein to any desired ratio, and also the graduating such softness to any
desired degree, substantially in the manner and for the purposes herein-before set
forth and described.
In witness whereof, I, the said Robert Hadfield, have hereunto set my hand
and seal, this Eleventh day of April, in the year of our Lord One thousand
eight hundred and seventy-eight.
ROBERT HADFIELD. (L.S.)