IMPROVEMENTS IN TREATING SHEET-IRON PLATES FOR THE PURPOSE OF PREPARING THE SAME FOR BEING COATED WITH ZINC FOR PRODUCING THE SO-CALLED 'GALVANIZED IRON, AND ALSO FOR MANUFACTURING SUCH PLATES IN IMITATION OF RUSSIA IRON
Year: 1866

page_text: LETTERS PATENT to George Tomlinson Bousfield, of Loughborough Park;
Brixton, in the County of Surrey, for the Invention of "IMPROVEMENTS
IN TREATING SHEET-IRON PLATES FOR THE PURPOSE OF PREPARING THE SAME
FOR BEING COATED WITH ZINC FOR PRODUCING THE SO-CALLED 'GALVANIZED
IRON, AND ALSO FOR MANUFACTURING SUCH PLATES IN IMITATION OF
RUSSIA IRON."-A commuication from abroad by Charles Henry
Perkins, residing at Providence, Rhode Island, United States of
America.
Sealed the 25th January 1867, and dated the 30th October 1866.
COMPLETE SPECIFICATION filed by the said George Tomlinson Bousfield
at the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 30th October 1866, persuant to the 9th Section of
the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
TOMLINSON BOUSFIELD, of Loughborough Park, Brixton, in the County of
Surrey, do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN TREATING SHEET-IRON PLATES FOR THE PURPOSE OF PREPARING THE SAME FOR
BEING COATED WITH ZINC FOR PRODUCING THE SO-CALLED GALVANIZED IRON,'
AND ALSO FOR MANUFACTURING SUCH PLATES IN IMITATION OF RUSSIA IRON," (that
the same has been communicated to me from abroad by Charles Henry
[Price 8d.1

page_text: Perkins, a person resident at Providence, Rhode Island, United States of
America,) and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement thereof, that is to
say:-
The first division of the Invention consists in converting the common sheet
iron of commerce into an imitation of Russia iron by,-
1st, removing by mechanical means the superficial scale of oxide of iron
which coats the ouside of the sheet, and at the same time brightening the
surface of the sheet by friction.
2nd, subjecting the sheet so cleaned and brightened to theaction of a degree
of heat in a close oven sufficiently powerful to produce by partial oxidation
the dark blue color without developing fresh scales. For removing the
scale and brightening the surface various means may be employed, the most
convenient and efficient of which will be found to be the revolving rubbing
bed commonly employed in shops for working marble and freestone, or the
sheets may be placed upon a stationary table and their surfaces cleaned and
brightened by the action of reciprocating rubbers, between which and the
surface of the plate is sprinkled sand moistened with water.
The sheets being now free of all scale, and rendered bright in the manner
described or by any other preferred means, are enclosed in a box and placed
in an oven, the temperature of which is about 500° of Fahrenheit, at
which point the deep blue color which distinguishes Russia iron will be
obtained.
and
Common sheet iron tieated as above described willexhibitalltheappearances
possess the qualities of Russia sheet, that is to say, it will have a smooth
lustrous surface of a deep blue color, and when bent at a sharp angle will
throw up no superficial scale. So far as tenacity and ductility is concerned
these qualities will depend upon the structure of the iron, for it will not be
understoodthattheprocessabovedescribedaffects anything beyond the surface
of the sheet.
The second division of the Invention relates more particularly to a process
for preparing plates of sheet iron that are intended to be coated with zinc,
tin, or similar metals, or which by a subsequent process are to be colored and
finished to imitate Russia iron. The great difficulty which has been experienced
in all attempts to manufacture either "galvanized or Russia iron"plates from
common sheet iron is the presence of the "scale," as it is termed, or the oxide
of iron,whichcoats the surface of the latter. All previous processesfor treating
sheet iron with a view to the manufacture above mentioned have proceeded
upon the supposition that it was necessary to remove this scale, and various

page_text: rich to to effect this purpose, depending upon either
mechanical or chemical action or both. The process herein described does
not involve as one of its steps in working it the removal of the superficial
oxide in the sense of separating the scale from the sheet, as in the instance
when the plates have been cleaned of scale by the use of mechanical or
chemical agents for that purpose, but on thecontrary the scales are converted
into pure iron by being deprived of the elements with which the iron is
combined to form the oxide during the process of its manufacture, and at the
same time the quality of the metal of the sheet is improved by driving off any
constituent impurities which it may contain. A convenient number of plates
of common sheet iron may be taken and packed in an iron flask of the proper
dimensions to accommodate them. The pile of plates is completely covered
as well as their surfaces between each pair with turnings or chips of iron.
The flask is similar in form to that used by moulders, but is provided with a
close fitting cover, which after the plates are put in the box and covered with
chips should be made at the joint as tight as possible to exclude all air, and
this can be done by smearing the joint with clay. The flask with its charge
of plates and iron is then placed in a furnace, which may be of the rever-
beratory character, or of any other preferred kind which will furnish a
uniform heat of a high temperature. The flask and its contents are thus
heated to a degree which it will be better to have not much short of the
point which the flask can endure without fusion. The flask is allowed to
remain exposed to this heat for a longer or a shorter period, depending upon
the condition of the furnace and the quality of the iron which is used, and
upon the average for about twelve hours. After the flask has become
sufficiently cooled it is opened, and the plates removed forthe next operation.
It will be found that each plate has undergone a change, both as to color and
quality, its surface is of the dull color of unpolished silver, and the scale will
be found to have been reconverted into pure iron, and in fact the impuritics
which existed in the iron of the body of the sheet will be found to have in a
great degree been dissipated, as the effect of the process of decarbonization
which it has undergone.
This part of the process is the same as that which has been generally
employed in making small castings malleable, and therefore it is not claimed
as a discovery that cast iron when subjected to a high heat in a close vessel
undergoes purification; but the Invention consists in the application of this
principle to sheet-iron plates, as an improved means for overcoming the
difficulties due to the presence of scale or other impurities in the manufacture
of Russia iron or of plates which are to be coated with zinc or other metals.

page_text: The several plates are next subjected to pressure by being passed between
the surfaces of polished rollers, the effect of which operation is to render the
two surfaces of the sheet smooth and bright, and to roll the films of pure
iron which formerly constituted the scale into the perfectly annealed sheet
so as to exhibit hardly a trace of their ever having existed. The effect of
the rollers, however, is to increase the density of the sheet, and in consequence
render it stiff, and as it is desirable, especially if Russia iron is to be maru-
factured, that the sheet should be perfectly annealed, it is advisable to repeat
the operation of piling the sheets in a close flask with iron chips and turnings
as before, and expose them again to the heat of the furnace for a period of
twelve hours, more or less, according to their condition. The sheets having
been allowed to cool gradually when taken from the flask will be found to
be quite soft and deprived of all elasticity. Their color more nearly than
before approaches to that of dull silver, and an examination will show that
the metal is decarbonized throughout. Plates thus prepared are now ready
to be blued if the same are to be finished to imitate Russia iron by the
process in the first division above described, or by any other process which_
will accomplish the result, and if instead of blueing the sheets it is intended
to cover them with a coating of zinc to produce galvanized iron, or with any
other metal, their surfaces are in proper condition to readily take on such
coating when dipped in the bath prepared for that purpose according to the
method employed in such manufacture.
Although the Invention set forth in this division is especially adapted to
the preparation of sheet iron plates for galvanizing, tinning, or otherwise
coating them with metallic substances, and for manufacturing Russia iron,
it is obvious that the same principle can be successfully employed in preparing
other articles, as, for example, nails and screws for receiving a coating of
metal to prevent oxidation.
It will be observed that the process just described accomplishes not only
the cleaning of the plates on their surfaces, but improves the quality of the
iron of which they are composed, whereas all former processes do not com-
prehend more than the cleaning and smoothing of the surfaces by chemical
or mechanical agents applied to such surfaces. It is not intended to confine
this part of the Invention to the use of cast-iron chips for covering the plates
while the same areexposed to the action of heat, but to include any equivalent
material which can be used for the purpose; for this part of the Invention
does not relate to the means by which the result of decarbonization is effected,
but to the application of the means described or the equivalent chemically
thereof for the purpose declared.

page_text: The last division of the Invention relates particularly to a means, for
blueing and imparting lustre to sheet-iron plates which have passed through
the previous preparatory stages. It is designed especially for use in con-
nection with the process for preparing plates in the second division of
the Invention above described, but it may also be used to blue and finish
plates which have been cleaned of scale and brightened by any other
process.
This part of the Invention consists in,-
First, subjecting the plates to the action of heat while enclosed in a tight
flask, the plates being so arranged with the flask that the surfaces of no two
of them shall be in contact, but each plate shall be suspended in a free air
space.
Second, in subjecting the sheets after the last-named process to the power
of rollers or to blow over its entire surface from a hammer or similar instrument.
A convenient number of plates which have been freed of scale and made ready
for blueing are taken and arranged in a flask of the proper size to accom-
modate them. The plates may be set up edgewise, their ends resting in upright
grooves made in the sides of the flask so that their surfaces shall not touch;
or they may be arranged in any other preferred way which will secure their
surfaces from contact with each other or with the sides of the flask. The
flask having been enclosed so as to be air-tight is then placed in an oven or
furnace chamber, and then subjected to a heat of about 700° for about fourteen
hours; the flask is then withdrawn and allowed to cool gradually. The whole
time consumed in the operation of heating and cooling will be usually not far
from thirty-six hours. Each sheet will when removed from the flask be found
to be of a uniform blue color throughout every portion of its surface, but such
color will be dead rather than lustrous. To obtain the high lustre which
distinguishes Russia iron each plate is next caused to be passed through a pair..
of polished rollers and subjected to pressure not sufficient to draw the sheet,
but enough only to compress its surface.
Instead of subjecting each plate singly to this operation, it is quite as well
to take two or more placed in a pile and pass them through the rollers
together. It has also been found that the same result upon the surface is
produced by hammering with a smooth-faced hammer or with a wooden
beetle the entire surface of the plate. This latter operation of subjecting the
sheets to the pressure of rollers or the percussion of hammers imparts to their
surface a bright enduring lustre, which in point of appearance and durability
is fully equal to the best Russia iron, and where the process described in the
second division of the Invention above set forth is employed for preparing the

page_text: plate in connection with the process herein described for blueing, annealing,
and finishing them. The article when produced, when made from ordinary
American sheet iron of suitable grade, is in quality, pliability, and density, as
well as in appearance, in no respect inferior to the best specimens of Russia
manufacture.
What is claimed as the Invention is, first, the process substantially as herein
described for treating sheet-iron plates, which consist in, 1st, removing by
mechanical means the superficial scale of oxide of iron from the surface of
sheets; and, 2nd, subjecting the sheet so cleaned to the action of a degree
of heat in a close oven sufficiently powerful to produce by partial oxidation a
dark blue color.
Second, proparing plates of sheet iron, whether for receiving a coating of
zinc or other metal, or preparatory for polishing and coloring in imitation of
Russia iron by the application of the decarbonizing process, substantially as
herein described.
Third, preparing plates of sheet iron for coloring in imitation of Russia
iron, by first decarbonizing them and then rolling them, substantially as
described.
Fourth, the process herein described of annealing and imparting a blue
color to sheet metal plates, consisting in subjecting such plates, which have
been previously suitably cleaned and brightened, to the action of heat applied
while the plates are enclosed in a close flask, the plates being so arranged
within the flask that their surfaces shall be surrounded by a free air space
substantially as set forth.
Fifth, the process herein described of finishing sheet-iron plates by first
coloring the same in the manner above set forth; and, secondly, in subjecting
the plates after being colored to the action of pressure rollers or equivalent
means for producing a dense and lustrous surface, substantially as described.
In witness whereof, I, the said George Tomlinson Bousfield, have here-
unto set my hand and seal, this Twenty-third day of October, in the
year of our Lord One thousand eight hundred and sixty-six.