Improvements in Iron Castings and Mode of Producing the same.
Year: 1898

page_text: Date of Application, 7th Mar., 1898
Compinto Crocifiontion Loft 1ot line
1900 Accented 14th Jan 1800
PROVISIONAL SPECIFICATION.
Improvements in Iron Castings and Mode of Producing the same.
We, SAMUEL HUFTY, of Camden, New Jersey, United States of America, and
JOSEPH KAY CALDWELL, of Germantown, Philadelphia, State of Pennsylvania,
United States of America, Mechanical Engineers, do hereby declare the nature
of this invention to be as follows:-
-
Our invention consists of improvements in iron castings whereby they are
rendred highly tenacious soft, malleable, and easily machined; capable of being
readily forged and welded and susceptible of hardening or tempering in either
oil or water, such castings being not only applicable for all purposes 10r which
castings of iron are generally used but also for many purposes for which steel
castings or even steel forgings are now employed.
The invention also consists of a mode of making such castings.
The castings may in the first instance be composed of any ordinary white cast
iron suitable for the production of malleable iron castings, although it is pre-
ferable that the iron should contain some free carbon and a considerable per-
centage of silicon, an iron which, after melting, contains about the following
proportions of combined carbon, graphite, manganese, silicon, sulphur and phos-
phorus, being suggested as the preferable one from which to make the original
castings.
Combined carbon
Graphite
Manganese
Silicon
Sulphur
Phosphorus
2.75.
.50.
*150.
.750.
*020.
*015.
The castings are placed in a furnace in which they can be raised to and main-
tained at a high temperature, and for this purpose we can use any form of furnace in
which the flow of air and of the products of combustion is susceptible of regulation.
It is well known that the three states in which matter is cognizable namely, the
gaseous the liquid and the solid differ from each other merely in the closeness
of their molecular aggregation, in other words, solidification is merely the union
of molecules of a simple type, that is to say, the gaseous or liquid type, into a
more complex molecular aggregation. It is also well known that the molecular
aggregations of all substances, even the most dense, are in constant motion, this
molecular motion, in very dense solids, however, being restricted to a mere oscilla-
tion about a mean central position so that the configuration of the molecular
aggregates remains nearly constant.
The density of the bodies and consequently the greater or less freedom of
motion among their molecular aggregates is merely a function of temperature
and pressure, density decreasing and freedom of motion increasing as the tem-

page_text: perature increases until a temperature is reached at which the body becomes
soluble, although not necessarily liquid.
When the body becomes soluble, the molecular aggregates are capable of dis-
sociation and become free to re-arrange themselves in accordance with the ten-
dencies or accidents of their composition, and they do so re-arrange themselves,
that is to say, chemical reaction takes place and the making and re-making of
molecular aggregates goes on until a final arrangement is reached, this final
arrangement depending upon such accidents as the predominance of some par-
ticular constituent, the temperature at which the change takes place, the pressure
under which it takes place, or the rate of cooling.
Liquefaction is but an accident of solution and not an indispensible quality
of it, both liquidity and solidity being only special states of solution, dependent
only upon temperature and pressure, the true characteristics of solubility being
dissociation and re-arrangement of molecular aggregates which often takes place
in solids at temperatures far below that at which liquefaction occurs, though the
temperature at which the dissociation takes place is determined by pressure."
In white cast iron the aggregation of the combined iron and carbon molecules
is extremely close, as indicated by the density of the iron, and in the treatment
of such iron for the purpose of carrying out our invention we subject it to a
temperature at which the two solids, iron and carbon, become soluble in each other,
this temperature being much below the point of liquefaction, but being continued
for a considerable time.
The compound molecular aggregates being dissociated into their constitutent ele-
ments the atoms re-arrange themselves into new molecular aggregates, the final
arrangement being the permanent separation of the greater portion of the com-
bined iron and carbon while the pressure under which this dissociation
takes place prevents the free carbon from passing into higher complex molecular
aggregates, that is to say, the pressure compels the carbon to remain in its simplest
form of molecular aggregation and restricts the physical dimensions of the
carbon molecules, in which simple form of molecular aggregation the free carbon
does not interrupt the continuity of the iron, this peculiar characteristic rendering
our improved product so different in physical characteristics from ordinary grey
cast iron, although, like grey cast iron, it contains the original carbon in a state
capable of being both analytically and mechanically separated from the iron as
graphite, the graphite being, however, in an amorphous condition.
The separation of the carbon in this peculiar manner is due to the temperature
and pressure under which the separation takes place, the pressure within the solid
at the temperature of treatment being many times greater than that at which the
dissociation of the combined iron and carbon molecular aggregates takes place
in molten iron, and the change taking place during a rise of temperature or
during a long continued stationary or substantially stationary temperature, while
in ordinary grey cast iron the changes take place during a fall of temperature and
in a short space of time.
In producing iron castings in accordance with our invention the carbon passes
from a combined into an amorphous graphitic state little by little, the action
proceeding gradually throughout the mass at one and the same time.
The molecular changes take place without any marked deformation of the
physical shape of the castings, although small changes in physical form generally
occur and are apparent in altered density of the body.
In preparing iron castings in accordance with our invention we find it sufficient
in most cases to raise their temperature to about fifteen hundred (1500) degrees
Fahrenheit and to continue the treatment for about two hours, although a higher
temperature and a longer treatment may be required where the original white
iron castings are of a particularly dense character.
As indicating the difference between an iron casting produced in accordance
with our invention and the ordinary white iron casting from which it is made,
we append analyses showing the respective proportions of combined carbon, gra-

page_text: phite, manganese, silicon, sulphur and phosphorus, in two samples, analysis No. 1
being of the iron before treatment and analysis No. 2 of similar iron after
treatment.
Combined carbon
Graphite
Manganese
Silicon
Sulphur
Phosphorus
No. 1.
2.96
.48
.136
.903
.208
.084
No. 2.
.73
2.71
.104
.837
.172
.080
While iron castings produced in accordance with our invention may be con-
sidered a special form of grey cast iron in which the graphite is in an allotropic,
but not identical form with that in grey iron, such castings possess so many
unique physical qualities that they are considered a new commercial product
standing midway between iron and steel and uniting in themselves the best
characteristics of both.
Castings in accordance with our invention have none of the characteristics of
white cast iron but, in their stead, the specific gravity and softness of grey iron,
together with the malleability and susceptibility to forging and welding which
are characteristics of soft steel, the strength and tenacity of a steel casting and
the hardening and tempering properties of high carbon steel, this hardening &
tempering quality, which marks the difference between castings of our invention
and ordinary iron or steel castings, being a peculiar characteristic which renders
castings made in accordance with our invention suitable for a large number of
purposes for which expensive high carbon steels are now employed.
As indicative of this we may say that the treated sample No. 2, before referred
to, was softer than soft steel, presented a soft and mossy fracture in which the
graphite was quite apparent could be plated out while cold to double its original
size, was drawn out into a file tang. made a sound weld at full yellow heat,
hardened in hoth oil and water and could be made to take temper by color,
while its tensile strength was increased from about 16,000 pounds to the square
inch in the original white iron casting to about 57,000 pounds to the square inch
in the treated casting.
The existence of carbon in the treated iron in the free or graphitic state greatly
adds to its durability for all purposes where friction plays a part and hence
renders the castings of especial value for the manufacture of gear wheels
other parts of machinery subjected to excessive friction.
Din 7th dox of March 1898
or
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Iron Castings and Mode of Producing the same.
We, SAMUEL HUFTY, of Camden, New Jersey, United States of America, and
JOSEPH KAY CALDWELL, of Germantown, Philadelphia, State of Pennsylvania,
United States of America, Mechanical Engineers, do hereby declare the nature

page_text: of this invention and in what manner the same is to be performed to be particu-
larly described and ascertained in and by the following statement:-
Our invention consists of improvements in iron castings whereby they are
rendered highly tenacious, soft, malleable, easily machined, capable of being
readily forged and welded, and susceptible of hardening, or tempering, in either
oil or water; such casting being not only applicable for all purposes which
castings of iron are generally used but also for many purposes for which steel
castings, or even steel forgings, are now employed.
The invention also consists of a mode of making such castings.
The castings may in the first instance, be composed of an ordinary white cast
iron suitable for the production of malleable iron castings, although it is pre-
ferable that the iron should. contain some free carbon and a considerable per-
centage of silicon, an iron which, after melting, contains about the following
proportions of combined carbon, graphite, manganese, silicon, sulphur and phos-
phorus, being a suitable, or preferable one from which to make the original
castings.
Combined carbon
Graphite
Manganese
Silicon
Sulphur
Phosphorus
2.75.
.50.
*150.
*750.
*020.
*015.
The castings are placed in a furnace in which they can be raised to, and main-
tained at, a high temperature, we using for this purpose any form of furnace in
which the flow of air, and of the products of combustion can be regulated.
It is well known that the three states in which matter can exist namely, the
gaseous, the liquid, and the solid, differ from cach other merely in the closeness
of their molecular aggregation, in other words, solidification is merely the union
of molecules of a simple type, that is to say, the gaseous, or liquid, type, into a
more complex molecular aggregation. It is also well known that 'the molecular
aggregations of all substances, even the most dense, are in constant motion, this
molecular motion, in very dense solids, however, being restricted to a mere oscilla-
tion about a mean central position so that the configuration of the molecular
aggregates remains nearly constant.
The density of the bodies and consequently the greater, or lesser, freedom of
motion among their molecular aggregates is merely a function of temperature
and pressure, density decreasing, and freedom of motion increasing, as the tem-
perature increases, until a temperature is reached at which the body becomes
soluble although not necessarily liquid.
When the body becomes soluble, the molecular aggregates are capable of dis- 4
sociation and become free to re-arrange themselves in accordance with the ten-
dencies, or accidents, of their composition, and they do so re-arrange themselves,
that is to say, chemical reaction takes place and the making, and remaking, of
molecular aggregates goes on until a final arrangement is reached, this final
arrangement depending upon such accidents as the predominance of some par-
ticular constituent, the temperature at which the change takes place, the pressure
under which it takes place, or the rate of cooling.
4
Liquefaction is but an accident of solution and not an indispensible quality
of it, both liquidity and solidity being only special states of solution, dependent
only upon temperature and pressure, the true characteristics of solubility being 5
dissociation and re-arrangement of molecular aggregates, which often take place
in solids at temperatures far below that at which liquefaction occurs, though the
temperature at which the dissociation takes place is determined by pressure.
In white cast iron the aggregation of the combined iron and carbon molecules
is extremely close, as indicated by the density of the iron, and in the treatment 5

page_text: of such iron, for the purpose of carrying out our invention, we subject it to a
temperature at which the two solids, iron and carbon, become soluble in each other,
this temperature being much below the point of liquefaction, but being continued
for a considerable time.
The compound molecular aggregates being dissociated into simpler molecular
forms, and these again into their atomic constituents, the atoms re-arrange them-
selves into new molecular aggregates, the final arrangement being the permanent
separation of the greater portion of the combined iron and carbon, while the
pressure under which the dissociation takes place prevents the free carbon from
passing into higher complex molecular aggregates, that is to say, the pressure
compels the carbon to remain in its simplest form of atomic aggregation and
restricts the physical dimensions of the carbon molecules which are in an amor-
phous condition and hence distinguished from the graphite of cast iron.
This amorphous condition is evidenced by the fact, demonstrated by analytical
tests, that the carbon in our castings has a specific gravity of about one and eight-
tenths (18), a calorific power of about eight thousand (8000) heat units, and a
specific heat of about twenty four hundred ten-thousandths (2400) and therefore
answers the conditions which are recognised as distinguishing amorphous carbon.
The exact figures of the specific analysis referred to are as follows:-
Carbon obtained from a casting treated in accordance with our invention was
found to have a specific gravity of one and eight-tenths (1'8) as compared with
water whereas the specific gravity of graphite obtained from cast iron is, as is
well known, from two and two tenths (22) to two and four-tenths (24) and the
specific gravity of amorphous carbon from one and six-tenths (16) to two (2).
The calorific power of one gram of the carbon obtained from our casting was
determined by calorimeter test to be 7997 heat units, whereas the calorific power
of graphite obtained from cast iron is 7770, and that of amorphous carbon 8080
heat units. The specific heat of the carbon obtained from our casting was found
to be 2397 whereas the specific heat of graphite obtained from cast iron is '2008,
and that of amorphous carbon '2415.
The character of the carbon in different castings, made in accordance with our
invention, may, however, without materially affecting the drawing, welding,
hardening, or tempering, qualities of the same, vary to some extent in respect
of specific gravity, calorific power and specific heat, depending upon the varying
character of the iron before treatment, or other causes, hence we do not limit
ourselves to the specific figures hereinbefore given.
In all cases, however, the carbon, as regards the properties named, resembles
amorphous carbon, and is, as regards the said properties, materially and demon-
strably different from the graphite of cast iron, whether the latter be ordinary,
or malleable, cast iron.
The separation of the carbon in this peculiar manner is due to the temperature
and pressure under which the separation takes place, the pressure within the solid
at the temperature of treatment being many times greater than that at which the
dissociation of the combined iron and carbon molecular aggregates takes place
in molten iron, and the change taking place during a rise of temperature, or
during a long continued stationary, or substantially stationary, temperature;
while in ordinary gray cast iron the changes take place during a fall of tem-
perature and in a short space of time.
In producing iron castings in accordance with our invention the carbon passes
from a combined into an amorphous graphitic state little by little, the action
proceeding gradually throughout the mass during the continuation of the treat-
ment.
The molecular changes take place without any marked deformation of the
physical shape of the castings, although small changes in physical form generally
occur and are apparaent in altered density of the body.
In preparing iron castings in accordance with our invention we find it sufficient
in most cases to raise their temperature to about fifteen hundred (1500) degrees

page_text: Fahrenheit and to continue the treatment for about two hours, although a higher
temperature, and a longer treatment, may be required where the original white
iron castings are of a particularly dense character.
As indicating the difference between an iron casting produced in accordance
with our invention and the ordinary white iron casting from which it is made,
we append analyses showing the respective proportions of combined carbon, gra-
phite, manganese, silicon, sulphur and phosphorus, in two samples, analysis No. 1
being of the iron before treatment and analysis No. 2 of similar iron after
treatment.
No. 1.
No. 2.
Combined carbon
-
2.96
Graphite
.48
Manganese
.136
Silicon
.903
Sulphur
.208
Phosphorus
.084
.73
2.71
.104
.837
.172
.080
While iron castings produced in accordance with our invention may be con-
sidered a special form of gray cast iron in which the graphite is in a form allo-
tropic, but not identical, with that in gray iron, such castings possess so many
unique physical qualities that they are considered a new commercial product
standing midway between iron and steel and uniting in themselves the best
characteristics of both.
Castings in accordance with our invention have none of the characteristics of
white cast iron, but in their stead, the specific gravity and softness of gray iron.
together with the malleability and susceptibility to forging and welding which
are characteristic of soft steel, the strength and tenacity of a steel casting and
the hardening and tempering properties of high carbon steel, this hardening and
tempering quality, which marks the difference between castings of our invention
and ordinary iron or steel castings. being a peculiar characteristic which renders
castings made in accordance with our invention suitable for a large number of
purposes for which expensive high carbon steels are now emploved.
As indicative of this we may say that the treated sample No. 2, before referred
to, was softer than soft steel, presented a soft and mossv fracture in which the
graphite was quite apparent, could be plated out while cold to double its original
size. was drawn out into a file tang, made a sound weld at full yellow heat,
hardened in both oil and water and could be made to take temper by colour.
while its tensile strength was increased from about 16,000 pounds to the square
inch in the original white iron casting, to about 57,000 pounds to the square inch
in the treated casting.
The existence of carbon in the treated iron in the free, or graphitic, state, greatly
adds to its durability for all purposes where friction plays a part, and hence
renders the castings of especial value for the manufacture of gear wheels, or
other parts of machinery subjected to excessive friction.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed we declare that what
we claim is:-
1. A. casting of iron susceptible of being drawn, welded, hardened, or tempered,
and containing, throughout its mass, allotropic carbon in amorphous condition.
2. A casting of iron susceptible of being drawn, welded, hardened, or tempered,
and containing, throughout its mass, allotropic carbon in amorphous condition and
in excess of two per cent.
3. A casting of iron susceptible of being drawn, welded, hardened, or tempered,
and containing, throughout its mass, allotropic carbon in amorphous condition
and much in exess of the combined carbon.

page_text: 4. The production of iron castings, capable of being drawn, welded, hardened,
or tempered, by heating a white iron casting to a temperature but little, if any,
in excess of that necessary to cause solution, or dissociation, of molecular aggre-
gates, and maintaining the said heat until the greater portion of the combined
carbon has been converted to allotropic carbon in amorphous condition.
Dated this 1st day of December 1898.
JOHNSONS & WILLCOX,
47, Lincoln's Inn Fields, London, W.C., Agents.