IMPROVEMENTS IN THE MANUFACTURE OF SHEET IRON
Year: 1858

page_text: PROVISIONAL SPECIFICATION left by William Edward Newton at the
Office of the Commissioners of Patents, with his Petition, on the 30th
March 1858.-A communication..
I, WILLIAM EDWARD NEWTON, of the Office for Patents, 66, Chancery Lane,
in the County of Middlesex, Civil Engineer, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SHEET IRON," to
be as follows:-
The objects of this Invention are so to regulate the oxydation or formation
of scale upon the surface of sheet iron, as to give the scale such a quality as to
afford protection to the iron to prevent it from rusting, also to make it possess
greater toughness than when manufactured in the usual manner, and otherwise
to increase its valuable qualities.
When a piece of bright wrought iron is heated and exposed to the
atmosphere it changes color, owing to the formation on its surface of a scale
of oxide, the color and character of which depend on the nature of the:
oxidizing agent; if the iron does not become red hot, but is kept about the
temperature at which lead melts, it is not attacked by free oxygen, but is
oxidized by carbonic acid and moisture, and the scale formed in this way has
a rich blue black color, is thin, tough, smooth, and even, and clings to the iron
very tenaciously. But if the temperature of the iron be increased above a
low red heat heat, it combines directly with free oxygen; and if the tom-

page_text: perature be further increased to that at which cast iron melts, its affinity for
oxygen becomes so great that it takes fire and burns, and the scale of oxide
which is formed by allowing free oxygen to combine with the iron has a rough
rusty appearance, is very brittle and does not cling tenaciously to the iron.
Iron may however be oxidized at any temperature by carbonic acid, and
some other substances which it partly decomposes, and the scale thus produced
resembles in appearance that formed at or below a red heat. The thin,
smooth, tough, and tenacious scale of black oxide, formed by the action of
carbonic acid, adds greatly to the beauty of the iron and protects it from rust,
but the rough uneven brittle scale of red oxide, formed by the action of free
oxygen, not only gives the iron an unsightly appearance, but is of little value
as a protection against rust. It it not however only in the quality of its scale
that iron which has been exposed at a high temperature to the action of the
free oxygen is inferior to that which has been protected therefrom and
oxidized by carbonic acid, or a substance which it partly decomposes, but that
which has been attacked by free oxygen becomes brittle, while that oxidized
by carbonic acid or other agent which it partly decomposes, has not its tough-
ness affected, but, on the contrary, when iron containing carbon and other
impurities, such as sulphur, phosphorus, manganese, or silicon is exposed
at a high temperature to the last mentioned agents, it is decarbonized and
purified, and its toughness is thereby increased.
Furthermore, iron at a high heat is also very injuriously affected by exposure
to sulphurous and other deleterious gases which are evolved from some fuels,
and are frequently present in furnaces used in the heating of iron, such gases
having the effect of rendering the iron brittle, and giving it a strong tendency
to rust when exposed to the atmosphere.
The present Invention consists in rolling the iron in its manufacture into
sheet iron in a bath of pulverized iron ore, or ores of zinc, manganese, or
other metals, or of earthy matters, which are partly decomposed by contact
with the heated iron, and which by such partial decomposition are caused to
react upon the iron. This object is effected by covering or partially covering
the rollers with pulverized clay, ironstone, or other ore of iron or suitable
substance, so that the iron while passing between the rolls will be covered up
by the pulverized ore, and protected from the action of the atmosphere. The
heat evolved from the iron will act upon the pulverized material, and partially
decompose it by causing it to give out some of the gases it contains, and
which gases will react on the iron, and by forming a peculiar kind of scale or
coating on the iron will protect the same from the action of the atmosphere.
The Invention also consists in heating, or reheating, or annealing plates of

page_text: iron in the presence of pulverized iron or other ores or substances, or in a
bath or baths of the substances above specified, or of any such substances as
will serve as a protection against the deleterious gases of the furnace, and
which pulverized materials will, by their presence or by their partial decom-
position, by reason of the heat they will be subjected to in the heating or
annealing processes, will give off gases that will protect the iron while under
operation. A convenient mode of applying the Invention to heating, re-
heating, or annealing sheet iron, consists in placing the sheets either on edge
or flat in a suitable iron box, and filling the same with the pulverized ore or
other substance, and then submitting the iron to the heating process. I do
not, however, intend to confine myself to that precise mode of applying the
Invention.