IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL
Year: 1845

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSIAH
MARSHALL HEATH, of Winchester Buildings, in the City of London, Iron
Master, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Fourth day of August, in the ninth year of Her reign, did,
for Herself, Her heirs and successors, give and grant unto me, the said Josiah
Marshall Heath, Her especial license, full power, sole privilege and authority,
that I, the said Josiah Marshall Heath, my executors, administrators, and
assigns, and such others as I, the said Josiah Marshall Heath, my executors,
administrators, or assigns, should at any time agree with, and no others, from:
time to time and at all times during the term of years therein mentioned, should
and lawfully might make, use, exercise, and vend, within England, Wales,
the Town of Berwick-upon-Tweed, and in all Her Majesty's Colonies and
Plantations abroad, and in the Islands of Jersey, Guernsey, Alderney, Sark, and.
Man, my Invention of "IMPROVEMENTS IN THE MANUFACTURE OF CAST STEEL;" in.
which said Letters Patent is contained a proviso obliging me, the said Josiah
Marshall Heath, by an instrument in writing under my hand and seal, par-.
ticularly to describe and ascertain the nature of my said Invention, and in
what manner the same is to be performed, and to cause the same to be
inrolled in Her Majesty's High Court of Chancery within six calendar months.
next and immediately after the date of the said in part recited Letters Patent,
as in and by the same, reference being thereunto had, will more fully and at.
large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Josiah Marshall Heath, do hereby declare that the nature of my said
Invention, and the manner in which the same is to be performed, is parti-
cularly described and ascertained in and by the following description thereof,
reference being had to the Drawings hereunto annexed, and to the letters
and figures marked thereon (that is to say):
In the month of April, One thousand eight hundred and thirty-nine, a
Patent was granted to me for certain improvements in the manufacture of
iron and steel, one of which improvements was a process for making cast
steel by melting pig iron in a cupola furnace, and decarburating the metal to
the degree required to produce steel by adding to it, while still remaining
fluid in the cupola, a sufficient proportion of malleable iron or of oxide of iron
or of manganese. Since that process was described I have found that the
same object, namely, the decarburation of pig iron to the degree required
to produce steel, may be much more conveniently and perfectly accomplished
by performing the process of decarburation in an apparatus distinct from that
in which the pig iron is melted; and the following is a description of the
process I now use:-The pig iron to be converted into steel may be melted in
a cupola or in a reverberatory furnace, or it may be run direct from a blast
furnace used for smelting iron ore; but the most suitable apparatus I con-
sider to be a common cupola furnace, blown with hot air, in order that the
metal when run out from it may retain the highest possible temperature.
The fluid pig iron should be run from the cupola or other furnace into
a receptacle made of any material capable of withstanding an intense heat,
similar in form to a common refinery, or to the shallow well of a rever-
beratory furnace for melting pig iron, and the quantity of fluid pig iron used
for one operation should occupy about one third or thereabouts of the capacity
of the receptacle. The interior of this receptacle and its contents should be
kept at the highest temperature that can be produced; and I find a very ready
and convenient method of producing this high temperature to be by means of
currents of ignited carbonic oxide gas conveyed through pipes placed round
the top of the receptacle, slightly inclined downwards, so as to bear upon the
surface of the fluid metal. A sufficient temperature for this purpose may also
be produced by a current of oxyhydrogen gas produced by directing a stream
of atmospheric air into a current of hydrogen gas formed from the decom-
position of water allowed to trickle upon malleable iron brought to a high
heat. In order to burn the carbonic oxide it is necessary to introduce along
with it a current of hot atmospheric air, or if a more intense heat is required a
current of oxygengas may be introduced along with the carbonic oxide gas. In

page_text: either case, however, care must be taken that the proportion of atmospheric
air or of oxygen gas does not exceed that which is required to convert
the carbonic oxide into carbonic acid,' as any excess of oxygen in the blast
would have a most injurious effect upon the melted metal in the receptacle.
The carbonic oxide may be obtained from the wase gas from the cupola
employed to melt the pig iron, or from a blast furnace, or it may be generated
in a separate apparatus by the imperfect combustion of any fuel, and the
application of it may be in any of the numerous and well-known methods
already in 'use. The proportion of hot atmospheric air or of oxygen gas
necessary to form carbonic acid may be exactly regulated by means of stop-
cocks or valves in the pipes, by which the hot air or oxygen gas is conveyed
into the streams of carbonic oxide.
I do not claim any method of producing the high temperature required
in my process of making steel as any part of my Invention. In order to
decarburate the fluid iron in the receptacle to the degree necessary to form
steel, I mix with it a certain portion of malleable iron, more or less, as I
wish to make the steel softer or harder; but for cast steel of a medium
degree of hardness, such as is used for general purposes, I find that about
equal proportions of pig and malleable iron answer best. The propor-
tions in which the pig and malleable iron should be mixed, however, will
much depend upon the quality of the former. If grey pig iron is used it will
require moré malleable iron to be mixed with it than if white pig iron is used.
This is a point the exact determination of which can only be arrived at
by testing the quality of the mixed fluid metal in the receptacle at intervals,
by taking out small samples in a metal ladle, and judging of the quality by
the fracture when cold. The malleable iron to be mixed with the fluid pig
iron in the receptacle may be in scraps or in any convenient form; but by far
the most economical, convénient, and purest state in which the malleable
iron can be used is in the granular form; produced by reducing any perfectly
pure oxide of iron to small fragments, and then submitting them to the well-
known process of cementation in a common converting furnace, such as is
used for converting bar iron into blister'd steel. The iron ore -in small
fragments is mixed with just that proportion of carbonaceous matter which
is sufficient to combine with its oxygen at a red heat in a close vessel; and
when the process is finished, malleable iron is obtained in the purest possible
state. Before adding the malleable iron' to the fluid pig iron, the former must
be brought to a white heat, and 'this may be done in a separate furnace.
But I find the most convenient method is to place the malleable iron on a
bed between the receptacle which holds the fluid pig iron and the chimney

page_text: The
up which the waste heat from the combustion of the gas passes.
malleable iron, when at a white heat, is raked into the receptacle containing
the fluid pig iron, and the whole is kept in fusion, and stirred about for a
sufficient time to produce intimate mixture and uniformity of composition in
the fluid mass; and when the assays taken from it shew that the steel is of
the desired quality, the contents of the receptacle are run off into moulds of
any size or form required. A vitreous flux should be used to defend the
surface of the fluid steel from the action of the atmospheric air while it is
in the receptacle; but I do not claim the use of it as any part of my
Invention.
The forms of the apparatus in which the process I have above described
may be performed may be various; I have described the one I consider best
adapted to the purpose, but I do not confine myself to the exclusive use of it.
In the accompanying Drawing are several views of the apparatus in which I
consider the process I have described may be most efficiently performed.
Fig. 1 is a sectional plan view, the upper part of the furnace being removed
to shew the interior; Fig. 2, a section taken in the line 1, 2, of Fig. 1; and
Fig. 3 a section taken in the line 3, 4, of Fig. 1. The letters in all the
Figures refer to the same parts of the apparatus. A is the cupola in which
the pig iron is melted. There is nothing peculiar in the form or size of this
furnace, but I prefer the use of heated air in blowing it, in order that the metal,
when run from it, may have the highest possible temperature. B is the bed
between the receptacle for the fluid metal and the chimney. The malleable iron
or deoxydated iron ore is placed upon this bed on either side of the channel K;
it is brought to the highest possible temperature by the passage over it of the
flame from the combustion of the gas and air introduced through the pipes G
and H. C, receptacle into which the melted pig iron is run from the cupola, and
into which the malleable iron at a white heat is raked through the door D,
and intimately mixed with the fluid pig iron by stirring with a wooden pole.
The temperature of the contents of the receptacle may be raised to any
degree required, by means of the combustion of any gas rich in carbon and
bydrogen, by mixing with it hot atmospheric air or oxygen gas; and the
proportions required to produce perfect combustion of the gas without
producing an oxidating flame may be exactly regulated by a stopcock or
walve L, placed on the pipe H. The receptacle may be of any size, according
to the quantity of steel which is required. I find the most convenient gas to
be used for this purpose is carbonic oxide, which may be collected from a
cupola or a blast furnace, or may be produced in a separate furnace by the
imperfect combustion of any refuse fuel. The means of producing and applying

page_text: this gas to the purposes of solid fuel have been frequently described, and are
well known. D is the door by which the malleable iron or deoxydated ore is
introduced upon the bed B, and by which it is raked into the receptacle. E,
a small door through which a bar of iron or a wooden pole is introduced, to
stir the fluid metal in the receptacle. F, tap hole by which the steel is run
into moulds from the receptacle. G, pipes through which the carbonic oxide
or other gas is conveyed to the receptacle. They should dip downwards
slightly, so that the flame from the ignited gas may play upon the contents of
the receptacle, and keep the whole in a fluid state. H, pipes through which
the hot atmospheric air or oxygen gas is conveyed to be mixed with the
gas in the pipes G. When atmospheric air is used, it may be heated by the
waste flame which passes up the chimney in the pipes I. The method of
arranging the gas and air pipes has been often described, and is well known.
K, the channel through which the liquid pig iron is run from the cupola or
blast furnace into the receptacle. L, valve by which the admission of hot atmo-
spheric air or oxygen gas is regulated, so as to produce perfect combustion.
What I now claim is the exclusive right of preparing cast steel by
decarburating pig iron to the degree required to form steel, by mixing with
the pig iron run from a cupola or other furnace into a separate receptacle
malleable iron in the proportion necessary to form steel, and running the
mixture of pig and malleable iron, while still fluid and in the state of cast
steel, into moulds from the receptacle.
In witness whereof, I, the said Josiah Marshall Heath, have hereunto
set my hand and seal, this Fourth day of February, in the year of
our Lord One thousand eight hundred and forty-six.