CERTAIN IMPROVEMENTS TO HINDER THE OXIDATION OF IRON IN ALL ITS VARIOUS STATES OF CAST METAL, STEEL, MALLEABLE IRON, AND ALSO TO RENDER MALLEABLE IRON MORE HARD AND DURABLE
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MOSES
POOLE, of the Patent Office, Serle Street, in the County of Middlesex,
Gentleman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twenty-seventh day of November, in the ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Moses Poole, my exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said Moses Poole, my
exors, 'admors, and assigns, or such others as I, the said Moses Poole, my
exors, admors, or assigns, should at any time agree with, and no others, from
time to time and at all times during the term of years therein expressed,
should and lawfully might make, use, exercise, and vend, within England,
Wales, and the Town of Berwick-upon-Tweed, my Invention of "CERTAIN
IMPROVEMENTS TO HINDER THE OXIDATION OF IRON IN ALL ITS VARIOUS STATES OF
CAST METAL, STEEL, MALLEABLE IRON, AND ALSO TO RENDER MALLEABLE IRON MORE
HARD AND DURABLE," communicated from abroad; in which said Letters Patent

page_text: is contained a proviso that I, the said Moses Poole, shall cause a particular
description of the nature of my said Invention, and in what manner the
same may be performed, to be inrolled in Her said Majesty's High Court of
Chancery within six calendar months next and immediately after the date of
the said in part recited Letters Patent, as in and by the same, reference being
thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Moses Poole, do hereby declare that the nature of the said Invention, and the
manner in which the same is to be performed, are fully described and ascer-
tained in and by the following statement thereof, that is to say:-
The first improvement consists in adding to cast iron, in its various com-
positions of cast metal and steel, a proportion of tin, copper, nickel, or anti-
mony, varying in quantity of these latter from two to ten per cent. of the
former, which will be found to hinder its oxydation, and renders it less brittle.
The second improvement consists in rendering malleable iron more hard
and durable, by coating it with steel or cast iron containing less carbon than
common cast metal (which forms the difference in composition been steel and
cast metal), and also applying thereto the addition of from two to ten per cent. of
tin, copper, nickel, or antimony; and also for modes in conducting the operation,
which will render the steel and metal coating of one mass or substance with
the iron coated.
The third improvement consists in improved modes of case-hardening, or
rendering malleable iron more hard and durable, and also preventing by this
means the oxydation of it, and also other compositions or compounds of iron.
I will now proceed to describe the mode of attaining my several improve-
ments,-
First, the mixture of copper, tin, nickel, or antimony, may be added in any
form or manner to cast metal, whilst fluxing, so as to get it mixed evenly
through the molten mass, and the proportion of two to ten per cent. of the
said metal or metals may be varied to suit the various purposes for which the
said cast metal may be applied; the more of these metals, up to ten
per cent. that is added, the less oxidizable and less brittle the compound
will be.
My second improvement consists in the coating of malleable. or wrought
iron with steel, or with the above-named mixture of metals, which will be
found particularly useful for axles of wheels, or other forms of iron subject
in their use to great friction. A furnace may be employed of any form
capable of melting cast metal; but if the fire plays over the surface of the
metal a flux composed of lime, alumina, sand, or any other substance

page_text: generally used for such purposes, is to be used with the metal to prevent the
action of the fire on the metal; but a more convenient mode (where the form
of the piece of iron to be coated will allow it) to be employed is to melt the
metal in a crucible placed in a furnace with coke, the same as is used by the
makers of cast steel, and by brass founders; and for an axle or any other
form of iron requiring a particular form or thickness only of the harder
metal to be cast upon it a crucible may be used of the particular form
and size so required, and made so as only to allow the particular thickness
of metal required to be cast round it, and which, when properly melted and
finished, as herein-after to be described, it may be left to cool without removing
the crucible, which, when cool, may be broken off, leaving the iron with its
covering of the form and thickness of coating required. The furnace and
vessel to contain the molten metal being prepared, a description of steel
is to be made in the following manner:-Common pig metal, or any form of
carburretted iron, is put in and melted; a portion from time to time of malleable
or scrap iron is added, until, by dipping (into the molten mass) a rod of
malleable iron no action or corrosive effect on the rod is observed; a little oxide
of manganese may be added with the scrap iron, as it is known to have a
good effect in making common steel. With some sorts of cast metal this
corrosive effect is so great as even to dissolve quickly (to a fine point) the
rod of iron introduced. Or the said molten metal may be formed of common
blister steel and pig metal; the proportion of one half to double the quantity
of cast steel to that of pig metal may be used, according to the hardness of
the steel coating required; or indeed any composition of steel now known may
be used, the Invention consisting in these instances not of the mixture of
metal forming the steel, but to the application of it in covering malleable or
wrought iron, and to the manner of doing it. Any addition of tin, copper, nickel,
or antimony, varying from two to ten per cent., may be used with the above, and
in most cases two per cent. is sufficient. It is indeed impossible to advise or
describe one best mixture of the coating metal, because it depends upon the
use the coating is to be applied to. Thus, for axles of railway carriages.
subject to violent concussions, a mixture of tin or copper, &c. with the steel
will be found highly useful; but where the effect of friction alone is to be
prevented, as in a stationary engine, the hardest steel will be best in
all these mixtures. However, the molten mass must be tried by an iron
rod to see if any corrosion of the rod takes place (which will almost always be
found to be the case with common cast metal), otherwise the coating will never
adhere as one mass with the coated metal; and in case corrosion is observed
pieces, of scrap iron must be added as before named. The molten mass being

page_text: thus prepared, the piece of iron to be coated must be dipped into the mass and
left to remain until it becomes of the same high heat as the molten metal; or
it may be heated previous to dipping it in; but in case a crucible is used only
containing a small quantity of the coating metal, the piece of wrought iron,
when introduced cold, will harden and cool the mass, but the heat must be
continued until the metal again becomes fluid, by which means the two metals
will unite as in one mass, and which, if well done, cannot be detached when
cold, although the piece of iron be hammered nearly flat.
As a guide to these mixtures of metals I repeat the following:-The more
malleable or scrap iron added to these mixtures of metals the less fragile will the
product be, but it will want hardness. Manganese added to the above in propor-
tion of five to ten per cent., of manganese and soda of each five to fifteen per
cent., increases the hardness in the proportion added, but if too much it makes
it too brittle. Copper added in proportion of two to ten per cent. keeps up the
hardness where a large proportion of manganese or blister steel is added, and
at the same time makes it much less brittle and fragile. Tin in the same
proportions approaches the same effect as copper, but not so much; it has the
advantage of rendering the molten mass more liquid. Blister steel in equal
quantity up to double the quantity to that of cast metal is very hard and
durable. After the steel coating is cast on over the iron it may be gradually
cooled, turned, and polished, and again hardened up by heating, and rapidly
cooling the same, as in the working of steel, with this precaution, that if the
coating is thick, from the steel and iron having different degrees of dilatation
in cooling, if plunged at once red hot into cold water it is apt to crack; it
must be more gradually cooled. In the case of an iron axle only coated at
the end, the iron may be plunged hot into water up to where the coating com-
mences, leaving it out of the water; the conducting power of the iron will cool
the coated part sufficiently rapid to give the necessary hardness.
The third part of my Invention consists in the rendering malleable iron
more hard and durable by a new mode of case-hardening, and which also
renders it and cast metal and steel less oxidizable.
I claim, first, as new, the use of ferrocyanide of sodium, calcium, barium, or
any other alkaline or alkaline earthy base, in preference to ferrocyanide of
potassium (now known to have that effect), as having a less corrosive effect on
iron.
I also claim the use of the salts of these alkaline and alkaline earthy bases
to mix with ferrocyanide of potassium to hinder the said corrosive effect on
iron. Also to prevent the oxidating effect of fire on iron in treating it to a
temperature between a red and white heat, and which is necessary to give full

page_text: effect in the case-hardening process. I employ and claim as new the use of a
bath of flux composed of carbonate of soda, or any of the above-named
alkaline salts, either by themselves or mixed with silica, alumina, or other
substance to form a flux that has no noxious effect on iron.
And I claim as my Invention the use of this bath of flux to heat up iron or
other metal from redness upwards, whether used in the process of case-
hardening, or for any other purpose when so used, to prevent the oxidation of
the metal at elevated temperatures by the fire, which is always the case when
iron or metals are heated in a fire or open flue with a draft of air through it.
By this means I can heat up to nearly a white heat a smooth and polished
piece of iron without its being at all oxidated, the surface remaining smooth
and untouched by the fire. The apparatus necessary is a simple reverberatory
furnace, with crucibles of metal or of earthenware; or for larger articles to be
case-hardened, two basins may be built in the solid brickwork, the fire passing
over them in the form of a flue, the one next the fire containing the flux, the
other the ferrocyanide. Carbonate of soda, or any other flux above named, is
put into the basin or crucible (as may be), melted, and kept so until it
attains nearly a white heat; the higher the heat the greater the hardening
effect. The piece of iron to be hardened is now plunged into the bath of flux,
and there brought up to the full heat; it is then put into the bath of ferro-
cyanide (which is also in a fluxed state) for a minute or less, or it may be
drawn out of the bath of soda flux and strewed or powdered over with
ferrocyanide in powder, the portion of alkaline flux adhering to it when taken.
from the bath preventing the corrosive effect of ferrocyanide of potassium,
should that ferrocyanide be used. The bath of ferrocyanide is more useful for
chain bolts, &c., but it has the defect of being soon decomposed, say in fifteen
or twenty minutes, that it is necessary to use it up quickly. But for axles,
where the end only is to be hardened, the crucible is more convenient; and if
the article to be case-hardened is placed upright the iron part above the turned
and polished part may be protected from the fire by lumps of coke, and which
has, besides, a good effect in heating the axle, which heat is conducted
down into the flux, by which means a crucible of cast metal may be used if
preferred, as the flux in that case does not require so high a degree of heat.
In witness whereof, I, the said Moses Poole, have hereunto set my
hand and seal, this Twenty-seventh day of May, in the year of our
Lord One thousand eight hundred and forty-six.

page_text: AND BE IT REMEMBERED, that on the Twenty-seventh day of May, in
the year of our Lord 1846, the aforesaid Moses Poole came before our said
Lady the Queen in Her Chancery, and acknowledged the Specification afore-
said, and all and every thing therein contained and specified, in form above
written. And also the Specification aforesaid was stamped according to the
tenor of the Statute made for that purpose.
Enrolled the Twenty-seventh day of May, in the year of our Lord One
:thousand eight hundred and forty-six.