mproveu maпитacтure of Steel
Year: 1897

page_text: mproveu maпитacтure of Steel,
I, ROBERT ABBOTT HADFIELD, of The Grove, Endcliffe Vale Road, Sheffield,
in the County of York, Steel Manufacturer, do hereby declare the nature of
this invention to be as follows:-
The object of this invention is the manufacture at a comparatively low cost of
hard steel possessing superior qualities and such as can be rolled and forged like
other hard steel and can be readily hardened with less or not more cracking than
occurs with costly crucible steel such as those in which expensive iron (for
example Dannemora) forms the basis..
•
According to my invention I add to decarbonized iron practically free from
or very low in manganese, a suitable proportion of carbon say from 0-60%
(decimal six per cent.) up to 25% (two decimal five per cent.) according to require-
ment by the introduction of a carbonaceous material practically free from
manganese, such, for example, as white iron of good pure quality low in sulphur
and phosphorous and practically free from manganese, adding at the same time
sufficient aluminium, or silicon, or both, according to requirement, and taking
care that the resulting product shall not contain more than about 02% (decimal
two per cent.) of manganese or as much less as possible, as I have discovered that
the presence of manganese in hard steel when the same is hardened tends to render
the steel brittle in a similar manner to but to a less degree than phosphorous.
For this reason I regard manganese as a deleterious substance in hard steel as
sulphur and phosphorous are regarded as deleterious substances in iron and steel,
and therefore a substance the presence of which should be avoided as much as
possible. I have found that when the amount of manganese is very low, steel of
superior quality can be produced containing a larger proportion of sulphur and of
phosphorus than would otherwise be admissible thus enabling me to use less
costly materials than have heretofore been considered necessary in the manufacture
of high quality steel.
For some purposes I make a steel of the kind herein before described containing
nickel the proportion of which may vary up to say about 7%, the resulting steel in
all cases being however low in manganese and capable of being hardened in the
mass, that is to say of being hardened throughout practically the whole of its
section even when the same is comparatively large, say several inches square.
In carrying out my invention I take iron such for example as is now used in the
production of acid steel and decarbonize it preferably by the pneumatic method
in a suitable vessel or converter, but it may be by treatment in an open hearth
furnace, care being taken to eliminate practically the whole of the carbon, man-
ganese and silicon it may contain. To the molten iron thus obtained I add car-
bonizing physic such as above described and in a melted state, and also aluminium,
or silicon, or both aluminium and silicon. these latter elements being preferably
used in small quantities say about 0·20% (decimal two per cent.)
It is important in order to obtain a satisfactory result that the carbon physic

page_text: and aluminium or silicon, or both aluminium and silicon, should not be added to
the molten iron whilst the same is in the converting vessel or furnace because by
adopting this method it is difficult to ensure that the resulting steel shall contain
the desired exact proportions of the added substances and shall be of uniform
quality. To obviate this difficulty I prefer to run successively into a ladle or
vessel carried by a suitable weighing machine, such as a Denison weighing
machine, or a platform weighing machine, the desired amount of carbonizing
physic such as hereinbefore referred to, previously melted, and then add to the
melted carbon physic the desired amount of aluminium which may be in the
metallic state and preferably in a melted condition, or the desired amount of
silicou, which may conveniently be in the form of ferro-silicon also in a melted
condition; or both aluminium and silicon may be added. There is also run into
the ladle the desired amount of nickel, in the form for example of ferro-nickel,
when it is desired to produce nickel steel such as hereinhefore mentioned. The
desired weights of the several substances (preferably previously melted in
crucibles) can be readily and accurately ascertained by means of the weighing
machine carrying the ladle into which the melted substances are run. Into the
weighed contents of the ladle, whilst the latter is carried by the weighing machine,
there is then run, preferably direct from the furnace, so much of the melted iron
as will increase the weight of the contents of the ladle so that of the required quan-
tity of my special steel low in manganese which is then run off into moulds to
form ingots or castings as may be desired. In this way practically exact pro-
portions and thorough admixture of the respective constituents constituting the
improved steel can be ensured.
Steel produced in the way described and containing respectively about 99%
(ninety nine per cent.) of iron, 90% (decimal nine per cent.) of carbon, and
0.20% (decimal two per cent.) of silicon and about 985% (ninety eight decimal
five per cent.) of iron, 125 % (one decimal two five per cent.) of carbon, and
0.25% (decimal two five per cent.) of silicon are examples of high quality hard
steels having the qualities above referred to. An alloy containing about 98:2%
(ninety eight decimal two per cent.) or iron: 0.90% (decimal nine per cent.) of
carbon, 0.20% (decimal two per cent.) of silicon, and 0-70% (decimal seven per
cent.) of nickel is an example of high quality hard nickel steel produced according
to my invention.
1007
I, ROBERT ABBOTT HADFIELD, of The Grove, Endcliffe Vale Road, Sheffield,
in the County of York, Steel Manufacturer, 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: —
The object of this invention is the manufacture at a comparatively low cost of
hard steel possessing superior qualities and such as can be rolled and forged like
other hard steel and can be readily hardened with less or not more cracking than

page_text: occurs with costly crucible steel such as those in which expensive iron (for
example Dannemora) forms the basis.
According to my invention I add to decarbonized iron practically free from
or very low in manganese, a suitable proportion of carbon say from 0°C %
(decimal six per cent.) up to 25%, (two decimal five per cent.) according to require-
ment by the introduction of a carbonaceous material practically free from
manganese, such, for example, as white iron of good pure quality low in sulphur
and phosphorus and practically free from manganese, adding at the same time
sufficient aluminium, or silicon, or both, according to requirement, and taking
care that the resulting product shall not contain more than about 02% (decimal
two per cent.) of manganese, or as much less as possible, as I have discovered that
the presence of manganese in hard steel when the same is hardened tends to render
the steel brittle in a similar manner to but to a less degree than phosphorus.
For this reason I regard manganese as a deleterious substance in hard steel as
sulphur and phosphorus are regarded as deleterious substances in iron and steel,
and therefore a substance the presence of which should be avoided as much as
possible.
For some purposes I make a steel of the kind hereinbefore described containing
nickel the proportion of which may vary up to say about 7% (seven per cent.) the
resulting steel in all cases being however low in manganese and capable of being
hardened in the mass, that is to say, of being hardened throughout practically the
whole of its section even when the same is comparatively large, say several inches
square.
In carrying out my invention I take iron such for example as is now used in the
production of acid steel and decarbonize it (preferably by the pneumatic method)
in a suitable vessel or converter, but it may be by treatment in an open hearth
furnace, care being taken to eliminate practically the whole of the carbon, man-
ganese and silicon it may contain. The various basic or semi-basic processes now
in use may also be employed for producing the iron required to form the base for
my physic additions. To the molten iron thus obtained I add carbonizing physic
such as above described and in a melted state, and also aluminium, or silicon, or
both aluminium and silicon, these latter elements being preferably used in small
quantities say about 02% (decimal two per cent.)
It is important in order to obtain a satisfactory result that the carbon physic
and aluminium or silicon, or both aluminium and silicon, should not be added to
the molten iron whilst the same is in the converting vessel or furnace because by
adopting this method it is difficult to ensure that the resulting steel shall contain
the desired exact proportions of the added substances and shall be of uniform
quality. To obviate this difficulty I prefer to run successively into a ladle or
vessel carried by a suitable weighing machine, such as a Denison weighing
machine, or a platform weighing machine, the desired amount of carbonizing
physic such as hereinbefore referred to, previously melted, and then add to the
melted carbonizing physic the desired amount of aluminium which may be in the
metallic state and preferably in a melted condition, or the desired amount of
silicon, which may conveniently be in the form of ferro-silicon also in a melted
condition: or both aluminium and silicon may be added. There is also run into
the ladle the desired amount of nickel, in the form for example of ferro-nickel,
when it is desired to produce nickel steel such as herein before mentioned. The
desired weights of the several substances (preferably previously melted in
crucibles) can be readily and accurately ascertained by means of the weighing
Into the
machine carrying the ladle into which the melted substances are run.
weighed contents of the ladle, whilst the latter is carried by the weighing machine,
there is then run. preferably direct from the furnace, so much of the melted iron
as will increase the weight of the contents of the ladle to that of the required quan-
tity of my special steel low in manganese which is then run off into moulds to
form ingots or castings as may he desired. In this way practically exact pro-

page_text: portions and thorough admixture of the respective constituents constituting the
improved steel can be ensured.
Steel produced in the way described and containing respectively about 98.9% (ninety
eight decimal nine per rent.) of iron, 0·9% (decimal nine per cent.) of carbon, and
02 (decimal two per cent) of silicon; and about 98.5% (ninety eight decimal five
per cent.) of iron, 1-25% (one decimal two five per cent) of carbon, and 0.25%
(decimal two five per cent.) of silicon are examples of high quality hard steels
having the qualities above referred to. An alloy containing about 982% (ninety
eight decimal two per cent.) of iron: 0.9% (decimal nine per cent.) of carbon,
02 (decimal two per cent) of silicon, and 7% (decimal seven per cent.) of
nickel is an example of high quality hard nickel steel produced according to my
invention.
I have found that when keeping the manganese low in quantity as set forth, it
is not necessary to employ high quality stock or raw material for the production
of my special alloy or improved steel. Thus whilst it has heretofore been necessary
in the production of hard steel of good quality, to employ the very highest quality
of raw material, such as Swedish pig or melting iron, I find that in producing
steel according to this invention, in which the manganese is kept low, hard steel
of superior quality can be produced containing a larger proportion of sulphur and
phosphorus than would be admissible if manganese were present in much larger
quantity, consequently I am able to use cheap raw stock such as ordinary hematite
pig iron, or even mixtures of ordinary pig iron and steel scrap. to form a suitable
basis of iron for forming my improved steel. Thus, whereas high quality raw
material containing sulphur and phosphorus only say up to about 002% (decimal
nought two per cent.) each, has heretofore been necessary for producing hard steel,
by keeping the manganese in the steel low in quantity as set forth, the sulphur and
phosphorus in the raw material may, without serious disadvantage, especially
when the steel is to be used for castings, he allowed to reach say about 0.05%
(decimal nought five per cent.) or 006% (decimal nought six per cont.) thus
rendering available a much wider range of raw material of comparatively small
cost for the production of high quality steel. Such a basis of iron must of course
be decarbonized, demanganized and desiliconized, as hereinbefore described, before
mixing the carbon, chromium and nickel therewith, sufficient silicon or aluminium.
or both, being also added to decompose any oxide there may be present. This
latter addition is important because there will be little or no manganese present for
effecting such decomposition.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed I desire to have it under-
stood that I do not intend to claim as of my present invention anything claimed
in the Specification of my previous Patent No. 13847 of 1893 but I declare that
what I do claim is:-
1. The herein above described improved manufacture of steel free from or low
in manganese and capable of being hardened in the mass as set forth, using as a
basis iron decarbonized, demanganized and desiliconized by the pneumatic method.
or by the open hearth method, with carbonizing physic, aluminium or silicon or
aluminium and silicon, with or without nickel, as set forth.
2. The manufacture of the herein described steel by decarbonizing, deman-
ganizing and desiliconizing iron and adding carbonizing physic, and aluminium or
silicon, or aluminium and silicon, and nickel when used, to the decarbonized,
demanganized and desiliconized iron, the said iron and other substances being
mixed together in a molten form in a ladle or vessel that is adapted by suitable
weighing mechanism to show the weight of its contents, and the said iron and the
other substances being added separately and successively so that the weight of
each and consequently the proportion thereof can be easily controlled as set forth.
3. The hereinabove described improved steel consisting of iron, carbon and

page_text: aluminium or silicon or aluminium and silicon substantially in or about the pro-
portions set forth.
4. The hereinabove described improved steel consisting of iron, carbon, nickel
and aluminium or silicon, or aluminium and silicon, substantially in or about
the proportions set forth.
Dated this 24th day of August 1898.
For the Applicant,
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.