IMPROVEMENTS IN ENAMELLING SHEETS OR PLATES OF IRON AND STEEL
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by John Thomson King at the Office of
the Commissioners of Patents on the 5th April 1879. A communication from
abroad by Albert Maltby, of Pittsburgh, Pennsylvania, United States of
America.
JOHN THOMSON KING, of Liverpool, in the County of Lancaster, Patent Agent.
"IMPROVEMENTS IN ENAMELLING SHEETS OR PLATES OF IRON AND STEEL." [A com-
munication from abroad by Albert Maltby, of Pittsburgh, Pennsylvania, United
States of America.]
My Invention relates to a novel process of polishing and forming a fast enamel
on plate or sheet iron or steel, to give it a fine smooth surface, and an enamel which
will not break off when bent, thereby preventing rusting or corrosion when exposed
to the air or dampness of any kind.
It consists substantially in de-oxydising the sheets or plates, annealing them in
an air tight compartment or box, rolling them while cold to the desired guage,
coating them with oil, and re-annealing them in an air-tight compartment; and
finally, polishing them between rolls or in any other suitable manner.
To enable others skilled in the art to make and use my Invention I will describe
the same more fully.
In carrying on my improved process I take plates or sheets of iron or steel of the
proper guage, the guage being determined by the thickness of the finished plate or
sheet to which it is to be rolled These sheets are then de-oxidised by subjecting
them to an acid bath, or by means of a blast of hot air, or any other process known
to those skilled in the art, thus removing the scale and leaving a pure metal surface.
They are then placed in an air tight compartment and annealed by being raised to
the proper heat in the usual method of annealing iron and steel, and are allowed to
cool until below the heat at which they will oxydise in the air before the removal
from the air tight box. The annealing of the sheets makes them soft and ductile,
so that they may be rolled down to the required guage. The cold sheets are then
rolled down between suitable rolls to the proper gunge for the finished sheets, thus
forming a smooth surface, perfectly free from imperfections and scale. This cold
rolling while forming the perfect surface on the plates and sheets will also harden
them and render them too stiff for many purposes for which they are required. To
remove this they are again annealed, the sheets being first coated with oil or grease
in any suitable way, and then placed in an air tight annealing compartment or box
and brought to a low heat. This second annealing renders the sheets soft and
077

page_text: ductile or pliable again, removing the hardness and stiffness, and giving the sheets
an exceedingly fine blue colour, so much desired in sheet metal. The sheets are
again allowed to cool below oxydising heat before removal from the annealing box,
when they are ready for polishing.
The plates and sheets thus treated may be polished either between rolls or by
friction applied to the surface by other methods. When it is desired to form a
mottled surface on the sheets, such as that of the Russia sheet iron, they are rolled
or passed between soft metal rolls, which gives the sheets a high polish, and at the
same time the large grain of the soft metal rolls press into the sheets and give to
them the desired mottled appearance. Where a fine smooth surface is desired the
plates or sheets are rolled between hard chilled rolls, which give a fine smooth
polished surface. The sheets may also be polished by friction applied in any
other suitable way.