IMPROVEMENTS IN THE PROCESS OF PREPARING COPPER FOR CASTING
Year: 1885

page_text: I WILLIAM ROBERT WALTON of Ansonia in the State of Connecticut, United
States of America Machinist do hereby declare the nature of said invention for
'IMPROVEMENTS IN THE PROCESS OF PREPARING COPPER FOR CASTING " to be as
follows:-
"
In casting ingots of copper, especially those that are tubular, for seamless tubes,
rollers etc great difficulty has heretofore been experienced in obtaining sufficient
solidity and in preventing the copper becoming brittle.
"
Copper that is being refined is subjected to what is known as the ".
"polling *
which is a stirring operation by a green pole; the effect of which is to produce a
violent ebullition of the copper and the carbon of the wood appears to combine with
the oxygen in the copper sufficiently to render the cast metal solid and malleable.
This "
polling" operation cannot be performed to advantage in remelting in
crucibles, on account of the ebullition.
This present invention is for treating copper in crucibles so as to exclude the
action of the atmosphere and subject the copper to the action of carbon stifficiently
to remove the oxygen and render such copper solid when cast and increase its
malleability and ductility.
I take about 8 lbs of zinc either in the form of an oxide or carbonate, and mix it
with 1 bushel of ground charcoal, wet it and make it into a stiff paste; portion it
out, say into 24 parts and make it into rough balls and dry in a moderate heat.
The copper is placed in the crucible in the furnace, and when on the point of
melting, one of the balls is dropped upon the copper and it gradually falls in pieces
and covers the copper as it melts down, thereby entirely excluding the atmosphere
from the surface of the copper, at the same time the zinc in the mass is evolved,
and dispells any oxygen which may remain in the crucible.
It may be supposed that the oxide of zinc will impregnate the copper, but such
is not the case, the charcoal coming in contact with the copper and the oxide of
zinc being volatile under the action of the heat, no combination with the copper
takes place, and the zinc is volatilized and carried off through the flue, while the
charcoal remains on the surface of the copper, and combines with any excess of
oxygen and burns and at the same time the carbon combines with the copper
sufficiently to cause it to remain solid when cast.

page_text: Copper treated in this way becomes perfectly malleable and is thoroughly
toughened and is in fact improved by this treatment. My improvement is
especially available when the copper is melted in a crucible, but it may be used
when melted on a hearth or otherwise.
The impurities of common copper are thrown to the surface in a slag, and the
copper made so that it will work better either hot or cold, and stand a greater test
for either tension or ductility.
The above method of treatment can be applied to copper that is to be used in
the manufacture of any article. Copper so treated will remain in a very liquid
state, much longer than that treated in the ordinary manner, and the copper can
also be brought to a very great heat without becoming decarbonized and losing its
toughness.
When casting such articles as tubes or small or thin castings a little phosphorus
added just before pouring, assists very materially in keeping the metal in a liquid
state and also prevents the absorption of oxygen from the atmosphere while cooling
in the moulds.
01270

page_text: :
C
5
Improvements in the Process of Preparing Copper for Casting.
:
I WILLIAM ROBERT WALTON, of Ansonia, in the State of Connecticut, United
States of America, Machinist do hereby declare the nature of this invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:—
In casting ingots of copper especially those that are tubular, for seamless tubes,
rollers &c, great difficulty has heretofore been experienced in obtaining sufficient
solidity and in preventing the copper becoming brittle.
Copper that is being refined is subjected to what is known as "poling" which is
a stirring operation by a green pole; the effect of which is to produce a violent
ebulition of the copper and the carbon of the wood appears to combine with the
oxygen in the copper sufficiently to render the cast metal solid and malleable.
This poling operation can not be performed to advantage in re-melting in crucibles
on account of the ebultion.
My present invention is for treating copper in crucibles so as to exclude the
action of the atmosphere and subject the copper to the action of carbon sufficiently
to remove the oxygen and render such copper solid when cast and increase its
malleability and ductility.
I take about eight (8) pounds of zinc either in the form of an oxide or carbonate
and mix it with one (1) bushel of ground charcoal, wet it and make it into a stiff
paste, portion it out say into twenty four (24) parts and make it into rough balls
and dry in a moderate heat.
The copper is placed in the crucible in the furnace and when on the point of
melting, one of the balls is dropped upon the copper and it gradually falls in pieces
and covers the copper as it melts down, thereby entirely excluding the atmosphere
from the surface of the copper at the same time the zinc in the mass is evolved and
dispells any oxygen which may remain in the crucible. It may be supposed that
the oxide of zinc will impregnate the copper but such is not the case, the charcoal
coming in contact with the copper and the oxide of zinc being volatile under the
action of the heat, no combination with the copper takes place and the zinc is
volatilized and carried off through the flue, while the charcoal remains on the
surface of the copper and combines with any excess of oxygen and burns and at the
same time the carbon combines with the copper sufficiently to cause it to remain
solid when cast.
Copper treated in this way becomes perfectly malleable and is thoroughly
toughened and is in fact improved by this treatment.
My improvement is especially available when the copper is melted in a crucible
but it may be used when melted on a hearth or otherwise.
The impurities of common copper are thrown to the surface in a slag and the
copper made so that it will work better either hot or cold and stand a greater test
for either tension or ductility.
The above method of treatment can be applied to copper that is to be used in
the manufacture of any article. Copper so treated will remain in a very liquid

page_text: state much longer than that treated in the ordinary manner and the copper can
also be brought to a very great heat without becoming de-carbonized and losing its
toughness.
When casting such articles as tubes or small or thin castings, a little phosphorous
added just before pouring assists very materially in keeping the metal in a liquid
state and also prevents the absorption of oxygen from the atmosphere while
cooling in the moulds.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
The method herein specified of treating copper to promote the density,
malleability and ductility of the metal when cast, consisting in melting such
copper and adding upon the surface of the metal as it melts, carbon mixed with
zinc in the form of an oxide or carbonate substantially as set forth.