Improvements in Treating Malleable or Wrought Iron.
Year: 1893

page_text: Date of Application, 10th May, 1893
Complete Specification Left, 9th Feb., 1894-Accepted, 10th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in Treating Malleable or Wrought Iron.
I, JOHN HASKINS LADD, of 116 Queen Victoria Street, in the City of London,
Engineer, do hereby declare the nature of this invention to be as follows:-
My invention relates to an improvement in processes of treating iron, and has
particular relation to the treatment of iron which has been previously decarburized
or which contains not more than five tenths of one per cent. of carbon and is of the
kind classified as malleable iron.
The purpose of my invention is to improve the quality of such iron when in a
fibrous condition, in a manner somewhat similar to the process known as cementation;
and my object is further to convert such iron into a fibrous condition when the same
shall have become crystallized from any cause; and my object is further to
accomplish the purposes here stated in an economic manner, both as to time and as
to cost.
My invention is based upon the discovery made by me that if iron, which has
assumed a crystalline character and which is sufficiently low in carbon, is subjected
to the action of a pure gaseous vapour, by which is meant a gaseous vapour
containing hydrogen, oxygen, nitrogen and carbon in proper combination and in
proper relative proportion to furnish a high temperature when burnt, and containing
no sulphur or other deleterious agent, the iron will be changed to a fibrous condition
and any sulphur or phosphorus that may be contained in the iron, or an appreciable
percentage thereof, will be removed if the exposure to the heat be continued for a
sufficient length of time. A further discovery which forms a basis for this invention
lies in the fact that the cementation of fibrous malleable iron, by which is meant the
introduction therein of carbon for its conversion into a steely iron, may be accom-
plished very successfully and with greater uniformity, and without danger of
causing deterioration, if a gaseous vapour be utilized to furnish the carbonaceous
flame with or without the addition of a further quantity of carbon combined with
the vapour, or in a separate combination, and substantially free from sulphur or its
compounds, which are thus not reintroduced during the process.
Heretofore the possibility of returning crystallized malleable iron to the fibrous
condition by frequent reheating and forging has been recognized to a greater or
less extent, and the eventual product is found to be sufficiently satisfactory so far
as the fibrous characteristic is concerned, but the product is much reduced in
strength as compared with other wrought iron. This deterioration is ascribed to
the presence of impurities from the furnace, the most prominent and objectionable
of which is sulphur in one or another of its forms. As compared with such a
process the process which I follow for the same end produces a result not only more
rapidly, requiring but a single heating for a period ordinarily not exceeding one to
two hours, and even as low as 40 minutes, without subsequent forging for the
purpose, but a result superior in the matter of quality and uniformity. The gas
composed essentially of the ingredients above outlined, which may be produced in a
manner hereinafter described, or any other satisfactory way, being itself entirely
free from sulphur, and burning with a temperature sufficiently bigh to maintain the
iron continuously during the period of treatment at a white heat without melting,
with or without subsequent rolling or hammering causes the conversion of the
crystallized to fibrous iron and removes sulphur. As a result the iron converted
by this process presents a closer long fibre and a greater tensile and transverse*
strength than iron previously having the same crystallized character and converted
with a coal furnace, or one employing a gas containing sulphur.

page_text: A convenient and desirable mode of producing such gas as is herein described is
the following:-
Atmospheric air at a normal temperature is caused to become charged with a
small percentage of hydrocarbon by bringing it into contact with the vapour of
a liquid hydrocarbon, and the carburetted air thus obtained is thereupon caused to
be charged to a sufficient extent with the vapour of water. The product, when
burnt, gives a very high temperature. As will be seen carbon in a comparatively
small proportion is combined with oxygen, nitrogen, and hydrogen, and the
compound is practically, if not absolutely, free from sulphur and other deleterious
agents.
In the practice of the process to which this invention relates for converting
crystallized into fibrous iron, as well as the process presently referred to for
accomplishing the cementation of iron, whether crystallized or not, as well as the
further manipulation by which scrap iron of a more or less crystallized character is
converted into a fibrous product, it is believed that the atmospheric air exerts an
important effect, as perhaps does also the hydrogen; but I am not prepared, at this
time, to assert positively the correctness of this theory. The carbon contained does
produce a material special effect in the treatment of the iron aside from contributing
its function in the matter of combustion.
Whether the iron be crystallized or fibrous, if it be introduced into a furnace
and subjected entirely to the heat of the gaseous compound above described,
together with the introduction of highly carburetted air at about the final period
of its maintenance in the furnace, and before the iron reaches the welding point the
result is found to be a uniform cementation of the wrought iron into steel. The
same process is employed for further carbonizing steel, without remelting, thus
hardening the product. I am aware that the cementation of wrought iron in
charcoal has been practised; and I am also aware that wrought iron has been
subjected to the action of a hydrocarbon flame produced in the ordinary way for
the same purpose; but in the first of these processes the introduction of deleterious
agents.has been unavoidable, and with the second not only has deterioration been
produced, though perhaps to a less extent, but the heat obtained from the com-
bustion of an ordinary hydrocarbon has been too slight to accomplish a material
change in a short time, and entirely insufficient to accomplish the best results under
the most favourable conditions.
As the amount of carbon to be introduced is, under ordinary circumstances, very
small, and may be merely a fraction of 1 per cent., the conveying power of the
gaseous fluid is found sufficient for the introduction of the extra amount of carbon
by my process; but if it is found insufficient at a normal pressure I find it advisable
to increase the pressure to such a degree as will enable the proper amount of carbon
to be introduced.
The making of wrought scrap into blooms involves a procedure substantially
identical with the process of converting crystallized into fibrous iron above described,
and particularly so if the wrought scrap be more or less crystallized. The piles
introduced into the furnace in the usual manner are subjected to a welding heat
produced with the gaseous compound free from sulphur and having the essential
ingredients above named. The operation, so far as have been able to observe it,
is to remove from the iron those agents which prevent welding and permit the
return of the continuity of the fibre under the operation of rolling or hammering.
By introducing into the iron, while in the furnace at a welding temperature, with
or without abnormal pressure, carburetted air, or merely carbonic oxide surcharged
with carbon or not, as may be determined, the product may be caused to attain a
steely property not heretofore found possible even under the most favourable
conditions with a coal or simple hydrocarbon furnace.
Doted this 10th day of May 1803

page_text: Improvements in Treating Malleable or Wrought Iron.
I, JOHN HASKINS LADD, of 116 Queen Victoria Street, in the City of London,
Engineer, 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 :-
My invention relates to an improvement in processes of treating iron, and has
particular relation to the treatment of iron which has been previously decarburized
or which contains not more than five-tenths of one per cent. of carbon and is of the
kind classified as malleable iron.
The purpose of my invention is to improve the quality of such iron when in a
fibrous condition, in a manner somewhat similar to the process known as cementation;
and my object is further to convert such iron into a fibrous condition when the same
shall have become crystallized from any cause; and my object is further to
accomplish the purposes here stated in an economic manner, both as to time and as
to cost.
My invention is based upon the discovery made by me that if iron, which has
assumed a crystalline character and which is sufficiently low in carbon, is subjected
to the action of a pure gaseous vapour, by which is meant a gaseous vapour
containing hydrogen, oxygen, nitrogen and carbon in proper combination and in
proper relative proportion to furnish a high temperature when burnt, having
combined with it a small percentage of vapour of water, and containing no sulphur
or other deleterious agent, the iron will be changed to a fibrous condition and any
sulphur or phosphorous that may be contained in the iron, or an appreciable
percentage thereof, will be removed if the exposure to the heat be continued for a
sufficient length of time. A further discovery which forms a basis for this
invention lies in the fact that the cementation of fibrous malleable iron, by which
is meant the introduction therein of carbon for its conversion into a steely iron,
may be accomplished very successfully and with greater uniformity and without
danger of causing deterioration, if a gaseous vapour having combined therewith a
small percentage of vapour of water, be utilized to furnish the carbonaceous flame
with or without the addition of a further quantity of carbon combined with the
vapour, or in a separate combination, and substantially free from sulphur or its
compounds which are thus not reintroduced during the process.
Heretofore the possibility of returning crystallized malleable iron to the fibrous
condition by frequent reheating and forging has been recognized to a greater or
less extent, and the eventual product is found to be sufficiently satisfactory so far
as the fibrous characteristic is concerned, but the product is much reduced in
strength as compared with other wrought iron. This deterioration is sometimes
ascribed to the presence of impurities from the furnace, the most prominent and
objectionable of which is sulphur in one or another of its forms. As compared
with such a process the process which I follow for the same end produces a result
not only more rapidly, requiring but a single heating for a period ordinarily not
exceeding one to two hours, and even as low as 40 minutes, without subsequent
forging for the purpose, but a result superior in the matter of quality and uniformity.
The gas composed essentially of the ingredients above outlined, which may be
produced in a manner hereinafter described, or any other satisfactory way, being
itself substantially free from sulphur, and burning with a temperature sufficiently
high to maintain the iron continuously during the period of treatment at a white
heat without melting, with or without subsequent rolling or hammering, causes the
conversion of the crystallized to fibrous iron and removes sulphur. As a result
the iron converted by this process presents a closer long fibre and a greater tensile
and transverse strength than irou previously having the same crystallized character

page_text: and converted with a coal furnace, or one employing an ordinary hydrocarbon
gas alone.
A convenient and desirable mode of. producing such gas as is herein described is
the following:-
A
Atmospheric air at a normal temperature is caused to become charged with a
small percentage of hydrocarbon (benzine) by bringing it into contact with the
vapour of a liquid hydrocarbon (benzine), and the carburetted air thus obtained is
thereupon caused to be charged to a sufficient extent with the vapour of water.
fair analysis will show about 3.395 grains of vapour of water to 45 grains of
vapour of benzine to the cubic foot of combined gas. This gas when burnt, gives
a very high temperature. As will be seen, carbon in a comparatively small
proportion is combined with oxygen, nitrogen and hydrogen, and the compound is
practically, if not absolutely, free from sulphur and other deleterious agents, and
contains an additional percentage of vapour of water, heretofore, it is understood,
believed to be detrimental, by itself, to the treatment of iron.
In the practice of the process to which this invention relates, for converting
crystallized into fibrous iron, as well as the process presently referred to for
accomplishing the cementation of iron, whether crystallized or not, as well as the
further manipulation by which scrap iron of a more or less crystallized character is
converted into a fibrous product, it is believed that the vapour of water, when
combined in the manner described with a hydrocarbon and atmospheric air exerts
an important effect, a comparison of results, with and without the use of the vapour
of water, showing an increase of utility approximating 25% or upward. The
carbon contained also, as before, produces a material special effect in the treatment
of the iron aside from contributing its function in the matter of combustion.
Whether the iron be crystallized or fibrous, if it be introduced into a furnace
and subjected entirely to the heat of the gaseous compound above described, together
with the introduction of highly carburetted air at about the final period of its
maintenance in the furnace, and before the iron reaches the welding point the
result is found to be a uniform cementation of the wrought iron into steel. The
same process is employed for further carburizing steel, without remelting, thus
hardening the product. I am aware that the cementation of wrought iron in
charcoal has been practiced; and I am also aware that wrought iron has been
subjected to the action of a hydrocarbon flame produced in the ordinary way for
the same purpose, but in the first of these processes the introduction of deleterious
agents has been unavoidable, and with the second not only has deterioration been
produced, though perhaps to a less extent, but the heat obtained from the combustion
of an ordinary hydrocarbon has been too slight to accomplish a material change in
a short time, and entirely insufficient to accomplish the best results under the most
favourable conditions.
As the amount of carbon to be introduced is, under ordinary circumstances, very
small, and may be merely a fraction of 1 per cent., the conveying power of the
gaseous fluid is found sufficient for the introduction of the extra amount of carbon
by my process; but if it is found insufficient at a normal pressure I find it advisable
to increase the pressure to such a degree as will enable the proper amount of carbon
to be introduced.
The making of wrought scrap into blooms involves a procedure substantially
identical with the process of converting crystallized into fibrous iron above
described, and particularly so if the wrought scrap be more or less crystallized.
The piles introduced into the furnace in the usual manner are subjected to a welding
heat produced with the gaseous compound having the essential ingredients above
named, to wit, air, hydrocarbon vapour and vapour of water, in about the
proportions named. The operation, so far as I have been able to observe it, is to
remove from the iron those agents which prevent welding and permit the return of
the continuity of the fibre under the operation of rolling or hammering. By
introducing into the iron, while in the furnace at a welding temperature, with or
without abnormal pressure, carburetted air, or merely carbonic oxide surcharged

page_text: with carbon or not, as may be determined, the product may be caused to attain a
steely property not heretofore found possible even under the most favourable
conditions with a coal or simple hydrocarbon furnace.
In demonstration of the improved character of the product made by the foregoing
procedures, the following may be given:
A test bar made from iron manufactured into a bloom in a coal furnace showed
a tensile strength of 48,127 lbs. A similar test bar made under similar conditions
but employing the heat obtained with the gaseous compound, above described,
showed a tensile strength of 51,146 lbs. Car axles were made from ordinary scrap
in a coal furnace of the best known pattern, forged into slabs and re-heated for
forging into axles, and three axles were also made from similar material treated
entirely with the gas having the above characteristics, and the lateral strength
tested. The gas made axles withstood a pressure equivalent to from 5 to 7 twenty
foot drops of a 1640 lbs. hammer more than the coal made axles, and the fracture
showed an essentially tough fibrous character, while the coal made axle showed a
distinctly crystalline fracture. The same difference in the character of the metal
is discovered if after treatment of the bar for from say 40 minutes to one hour
under the heat obtained from this gas, with or without the introduction before the
conclusion of the operation of an additional quantity of carbon, it is fractured for
purpose of examination. The fibre is steely in appearance and colour, and the
product thus made from common crystallized scrap bears a very close resemblance
to the best Swedish iron.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The process of treating crystallized wrought iron substantially free from
carbon, to change the same to a fibrous condition, which consists in subjecting the
iron to the action of a gaseous composition consisting of air, hydrocarbon vapour
and vapour of water, substantially of the nature described, in a state of combustion,
whereby the molecules assume throughout a fibrous structure, and the product is
otherwise improved, as set forth.
+
2. The process of treating malleable iron for the purpose described, which
consists in subjecting it to the action of a gaseous composition of air, hydrocarbon
vapour and vapour of water in combustion, to heat the iron to a welding point
without melting its mass, and before removing the iron from the heat, increasing the
proportion of carbon contained in the gaseous composition acting upon the iron,
substantially as described.
3. The process of treating iron which consists in piling the crystallized metal and
subjecting the same to the action of a gaseous composition in a state of combustion,
composed of. air, hydrocarbon (benzine) vapour and vapour of water in about the
proportions named and free from sulphur, maintaining the iron at the welding heat
obtained from said gaseous composition, and before removing the iron therefrom
increasing the carbon constituent of said gaseous composition, without introducing
sulphur, substantially in the manner and for the purpose described.
Dated this 30th day of January 1894.
JOHN H. LADD.
LADD.