AN IMPROVED PROCESS OF TREATING NON-CHILLING IRON TO CONVERT IT INTO CHILLING IRON
Year: 1878

page_text: LETTERS PATENT to John Thomson King, of Liverpool, in the County of
Lancaster, Patent Agent, for the Invention of "AN IMPROVED PROCESS OF
TREATING NON-CHILLING IRON TO CONVERT IT INTO CHILLING IRON." A
communication from abroad by Samuel A. Ford, of Alleghany, Pennsylvania,
United States of America.
Sealed the 1st October 1878, and dated the 1st April 1878.
PROVISIONAL SPECIFICATION left by the said John Thomson King at the
Office of the Commissioners of Patents on the 1st April 1878.
JOHN THOMSON KING, of Liverpool, in the County of Lancaster, Patent Agent.
"AN IMPROVED PROCESS OF TREATING NON-CHILLING IRON TO CONVERT IT INTO
CHILLING IRON." A communication from abroad by Samuel A. Ford, of Allegheny,
Pennsylvania, United States of America.
My Invention relates to the conversion of non-chilling into chilling irons, and
consists in submitting a charge of melted non-chilling iron to the action of an air
blast for a few moments only (say from 1 to 6 minutes), the air blast being cut off
either just before or just after the appearance of the carbon flame, according to the
depth of chill required in the product.
In the manufacture of pig metal two processes are commonly followed in the
blast furnace, the one known as the "cold blast" and the other as the "hot blast
process, and the products are known in the trade as "hot blast iron" and "cold
blast iron."
The cold blast iron is low in silicon, and is especially adapted for chill castings,
but its production is limited by the nature of the ore required and the small size of
furnaces it is practicable to work to advantage.
The hot blast iron, on the contrary, can be produced in any quantities desired, as
there is practically no limitation either in quality of ore or size of furnace; but the
hot blast iron is high in silicon, and though well adapted for the Bessemer process
is a non-chilling iron, totally unfit for the manufacture of chill castings.

page_text: The best chilling cold blast irons will average 1 of one per cent. of silicon, and
about four or five per cent. of carbon, and the average yield of a furnace worked by
the cold blast will be from eight to twelve tons of metal per day; but the hot blast
furnaces may be constructed to yield eighty or one hundred tons per day. The cost
of cold blast charcoal chilling iron will run at the present time thirty-five dollars to
forty dollars per ton, while the hot blast non-chilling iron can be procured at from
seventeen dollars to twenty dollars per ton.
The main object of the present Invention is to utilize the comparatively cheap
hot blast iron in the manufacture of chill rolls, car wheels, chill plows, malleable
castings, and under all similar circumstances where the more expensive cold blast
charcoal chilling irons are now necessarily used; but the process is equally applicable
to the treatment of light chilling. irons where it is desirable to increase the depth of
the chill.
I will now proceed to describe my Invention so that others skilled in the art to
which it appertains may apply the same.
Having melted the desired quantity of pig iron in a cupola or other suitable
furnace, or, if convenient, taking such a charge of molten iron directly from the
blast furnace, I introduco it into a furnace where it can be treated by an air blast.
For this purpose I prefer a Bessemer converter, wherein I submit the molten metal
to the action of the air blast a few moments, shutting off the blast either just before
or just after the appearance of the carbon flame, varying the time slightly, according
to the quality of the metal and the depth of chill required.
If only a small amount of chill is required I cut off the blast just before the
carbon of the metal begins to oxidize, which point can be determined by the
increased strength of the flame with absence of the brilliant yellow colour. When
a deep chill is desired the blow is continued until the brilliant yellow due to the
oxidation of the carbon appears in the flame, but it is cut off. before the disappear-
ance of the silicon flame or that flame which is seen at the commenceinent of the
blow. The blow having been carried to the extent indicated according to the
desired chill is then cut off and the metal poured into a ladle or other suitable
vessel, and thence directly into chill moulds, or into sand moulds for the formation
of castings, or into pigs which can be subsequently remelted in a cupola or other
suitable furnace for the manufacture of chill castings.
The whole process will usually occupy a space of time varying from one to five
minutes, but under some circumstances it may be necessary to continue the blow
somewhat longer, especially if the hot blast iron composing the charge be extremely
high in silicon.
The metal thus treated has not lost the qualities of cast iron, but will be found to
have acquired the properties of the "cold blast charcoal" chilling irons. It will be
found to be very hard, of great strength, and if cast in a chill mould will, when
broken, show long white crystals tapering into gray metal. When cast in sand
moulds, if the chilling property is not too great, it will exhibit a dark gray colour
and close grain resembling cold blast charcoal iron, but if the chilling property is
very high then the edges of the casting will be slightly chilled and the centre of
the piece of light gray colour.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said John Thomson King in the Great Seal Patent Office on the 1st October
1878.
-
JOHN THOMSON KING, of Liverpool, in the County of Lancaster, Patent Agent.
"AN IMPROVED PROCESS OF TREATING NON-CHILLING IRON TO CONVERT IT INTO
CHILLING IRON." A communication from abroad by Samuel A. Ford, of Allegheny,
Pennsylvania, United States of America.
My Invention relates to the conversion of non-chilling into chilling irons, and
consists in submitting a charge of melted non-chilling iron to the action of an air
blast for a few moments only (say from 1 to 6 minutes), the air blast being cut off
either just before or just after the appearance of the carbon flame, according to the
depth of chill required in the product.
In the manufacture of pig metal two processes are commonly followed in the
blast furnace, the one known as the "cold blast" and the other as the "hot blast"
process, and the products are known in the trade as "hot blast iron" and "cold
blast iron."
The cold blast iron is low in silicon, and is especially adapted for chill castings,
but its production is limited by the nature of the ore required and the small size of
furnaces it is practicable to work to advantage.
The hot blast iron, on the contrary, can be produced in any quantities desired, as
there is practically no limitation either in quality of ore or size of furnace; but the
hot blast iron is high in silicon, and though well adapted for the Bessemer process
is a non-chilling iron totally unfit for the manufacture of chill castings.
The best chilling cold blast irons will average 1 of one per cent. of silicon, and
about 4 or 5 per cent. of carbon, and the average yield of a furnace worked by the
cold blast will be from 8 to 12 tons of metal per day; but the hot blast furnaces
may be constructed to yield 80 or 100 tons per day. The cost of cold blast charcoal
chilling iron will run at the present time 35 to 40 dollars per ton, while the hot
blast non-chilling iron can be procured at from 17 to 20 dollars per ton.
The main object of the present Invention is to utilize the comparatively cheap
hot blast iron in the manufacture of chill rolls, car wheels, chill plows, malleable
castings, and under all similar circumstances where the more expensive cold blast
charcoal chilling irons are now necessarily used; but the process is equally applicable
to the treatment of light chilling irons where it is desirable to increase the depth of
the chill.
I will now proceed to describe my Invention so that others skilled in the art to
which it appertains may apply the same.
Having melted the desired quantity of pig iron in a cupola or other suitable
furnace, or, if convenient, taking such a charge of molten iron directly from the
blast furnace, I introduce it into a furnace where it can be treated by an air blast.
For this purpose I prefer a Bessemer converter, wherein I submit the molten metal
to the action of the air blast a few moments, shutting off the blast either just before
or just after the appearance of the carbon flame, varying the time slightly, according
to the quality of the metal and the depth of chill required.
If only a small amount of chill is required I cut off the blast just before the
carbon of the metal begins to oxidize, which point can be determined by the
increased strength of the flame with absence of the brilliant yellow colour. When
a deep chill is desired the blow is continued until the brilliant yellow due to the
oxidation of the carbon appears in the flame, but it is cut off before the disappear-
ance of the silicon flame or that flame which is seen at the commencement of the
blow. The blow having been carried to the extent indicated according to the
desired chill is then cut off and the metal poured into a ladle or other suitable
vessel, and thence directly into chill moulds or into sand moulds for the formation
of castings, or into pigs which can be subsequently remelted in a cupola or other
suitable furnace for the manufacture of chill castings.

page_text: The whole process will usually occupy a space of time varying from 1 to 5
minutes, but under some circumstances it may be necessary to continue the blow
somewhat longer, especially if the hot blast iron composing the charge be extremely
high in silicon.
The metal thus treated has not lost the qualities of cast iron, but will be found to
have acquired the properties of the cold blast charcoal chilling irons. It will be
found to be very hard, of great strength, and if cast in a chill mould will, when
broken, show long white crystals tapering into gray metal. When cast in sand
moulds, if the chilling property is not too great, it will exhibit a dark gray colour
and close grain resembling cold blast charcoal iron, but if the chilling property is
very high then the edges of the casting will be slightly chilled, and the center of
the piece of light gray colour.
Having thus described my Invention, what I claim and desire to secure by Letters
Patent is, the method herein described for converting non-chilling irons into chilling
irons, and for increasing the depth of chill in light chilling iron, which consists in
subjecting a charge of the melted metal to the action of an air blast for a limited
time only, the blow being cut off either immediately before or immediately after
the appearance of the carbon flame, and before the disappearance of the silicon
flame, substantially as specified.
In witness whereof, I, the said John Thomson King, have hereunto set my
hand and scal, the Twenty-fifth day of September, in the year of our Lord
One thousand eight hundred and seventy-eight
W. B. JOHNSON,
4, Clayton Sqr.,
Liverpool.
Witness.
J. T. KING. (L.S.)