Improved Methods for Effecting the Electro Fusion of Steel and its Alloys.
Year: 1893

page_text: PROVISIONAL SPECIFICATION.
Improved Methods for Effecting the Electro Fusion of Steel and
its Alloys.
BENJAMIN HOWARTI THWAITE of 87 Victoria Street Liverpool Civil
Engineer do hereby declare the nature of this invention to be as follows;-
My invention relates to methods for economically effecting the fusion of ferro
carbon of steel and its alloys by which such fusion is not only offected economically
and rapidly but in such a way as to produce a continuous or more or less con-
tinuus flow of metal and without producing deterioration of the fused metal.
My procedure, simply described, is as follows; I superpose one crucible over
another the latter however may be an ordinary open hearth steel furnace hearth
or it may be a chamber having a calcined basic or acid lined hearth or bottom,
similar in method of formation to that of an open hearth furnace.
At the bottom of the upper of the two crucibles, there is an opening provided
by which any fused metal in this crucible can flow into the lower crucible of
chamber-described as fast as fusion takes place through the sides of this
crucible I pass positive & negative carbon electrodes, which are so arranged that
the scrap or other steel can be easily and continuously fed.
The voltaic are as well as the resistance to the current set up by the metal
to be fused, soon provides the fusion temperature, and the metal flows into
the second chamber across which, I may fix two or more electrodes, so that in
this second chamber there is also established a fusion or steel melting temperature,
by which the steel can accumulate in a molten condition, when sufficient metal
has accumulated the tap hole is opened and the metal runs into a ladle to be cast
into ingots in the ordinary way.
When I employ a 2nd crucible below the upper one to receive tho metal, I
also establish an electro fusion temperature therein, and in the same way, I mount
this second or lowest crucible on trunnions so that when suflicient metal is
accumulated the crucible may be tipped- and the metal will run out into the ingot
or other mould.
In order to prevent the oxidation of the metal, I establish a reducing atmo-
sphere by introducing generator or other combustible gas such as CO) or carbon
monoxide having a low percentage of carbon dioxide into the upper part of each
crucible or fusion chamber.
I attach the negative and positive electrodes to the electric energy conductors
in any usual or well known manner. I may employ a series of electrodes each
radiating to the centre of the crucible, horizontally--and I may employ several
electrodes in the height of the crucibles--superposed either in direct or irregular
lines vertically so that zones of heat of enormous temperature intensity can
be established.
When I wish to reduce the carbon in the steel or otherwise alter its chemical
character, I do this in the lower chamber by any of the usual methods well
known for effecting this object. I may by adding different characters of ferro-
carbon in the upper crucible obtain any character of steel required.
Dated this 20th day of Varak 1909

page_text: Improved Methods for Effecting the Electro Fusion of Steel and
its Alloys.
I BENJAMIN HOWwantn Thwaite, of 95 Finsbury Pavement London, Civil
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 a method of economically effecting the fusion of ferro-
carbon of steel and its alloys, by which such fusion is not only effected economically
and rapidly, but in such a way as to produce a continuous flow, and without
producing deterioration of the metal produced.
My procedure simply described is as follows, I superpose one crucible, over
another, the latter however may be an ordinary open hearth steel furnace hearth,
or it may be a chamber having a calcined basic or acid lined hearth or bottom
similar in method of formation to that of an open hearth furnace.
The
At the bottom of the upper of the two crucibles, there is an opening provided,
by and through which, any fused metal in this crucible can flow into the lower
crucible or chamber described, as rapidly as fusion takes place, through the sides
of the crucible, I pass positive and negative carbon electrodes, which are so
arranged that the scrap or other steel, can be easily fed continuously.
voltair are as well as the resistance to the current, set up by the metal to be fused,
soon provides the fusion temperature, and the metal flows into the second chamber,
across which I may hx two or more electrodes, so that in this second chamber
there is also established a fusion of steel melting temperature, by which the
steel can accumulate in a molten condition, when sufficient metal has accumulated,
the tap hole is opened and the metal runs into a ladle to be cast into ingots in the
ordinary way.
When I employ a 2nd crucible below the upper one to receive the metal I also
establish an electro fusion temperature therein, and in the same way I mount this
second or lowest crucible on trunnions, so that when sufficient metal is necumu.
lated the crucible may be tipped, so that the metal will run out into the ingot or
other moulds.
In order to prevent the oxidation of the metal I establish a reducing atmosphere
by introducing generator or other combustible gas, having a low percentage of
carbon dioxide, into the upper part of each crucible or fusion chamber.
I attach the negative and positive electrodes to the electric energy conductors
in any usual or well known manner. I may employ a series of electrodes each
radiating to centre of the crucible, plano-ways or horizontally, and I may employ
several electrodes in the height of the crucibles, superposed either in direct or
irregular lines and vertically, so that zones of heat of enormous temperature
intensity can be established.
I provide a stopper plug arrangement whereby the fused metal in the upper
crucible or hearth can be prevented from flowing out of the crucible, or such
Blow can be regulated as desired.
When I wish to reduce the carbon in the steel or otherwise alter its chemical
character do this by any of the usual methods well known and in use for
effecting this object.
Referring to the two Figures, 1 & 2 showing respectively a vertical section and
elevation of the apparatus constituting my invention as applied for the production
of crucible or pot steel.
A is the upper one of the 2 crucibles of which B is the lower or receiving one.
The upper crucible A is provided with a sliding refractory cover C, which slides
around for uncovering and charging the crucible, being pivotted at I) -The pins
of the pivots being strongly proportioned.

page_text: The upper crucible A--is bedded on a refractory lining D—which is either formed
of refractory material such as fireclay or limestone or magnesia built in situ or of
specially shaped firebrick linings. The upper crucible merely rests on this
refractory lining and does not form part thereof. The part of the lining marked E
is repairable by the application of loam which is applied whenever a new crucible
is supplied.
They lining 1) of furnace, is kept in position by the W.I. casing 6,
which entirely encircles the upper crucible and is firmly constructed of anglo
irons and mild steel plates-the lower part of such casing is internally equipped
with an angle iron J supporting the refractory lining D. A cavity K is formed
beneath the upper crucible into which the end of these lower range of
electrodes L project-the voltaic are traversing the cavity K maintains the base of
the upper crucible A, as well as the lower crucible in a condition appropriate for
the reception of the fused metal from the upper crucible A. Two, four, or
six electrodes F may radially project into the upper crucible A, raising the metal
therein to a fusion temperature by which all the charged solid metal or ore is
rapidly fused and reduced and melted.
The fused metal can be allowed to flow into the lower crucible B by the tilting
of the stopper lever M by which the opening or passage N in upper crucible A
is uncovered, allowing the fused metal to flow into the lower crucible from which
it drops through the voltaic are formed between the terminals of the electrodes F.
The lower crucible is mounted on a swing lever on pivot on the wrought iron
standards P. so that the metal accumulated in the lower crucible B can be rapidly
tapped into the moulds.
The lower crucible B is supported by an open wrought iron frame R--which
allows a gas flame to entirely surround the lower crucible.
The elec-
In order to raise the temperature of the lower crucible to a satisfactory degreo
before charging into it the control in the upper crucible, I provide "Bunsen'
burner arrangements equipped with a flexible gas tube connection.
trodes L and L' are so arranged that they can be readily projected into the
crucibles. This is effected in the following manner.
The gun metal tube 2 threaded throughout is attached to flange 3 bolted to the
casing of the furnace on to this is screwed a sleeve piece having a milled head
projector 5, which can be easily turned by hand and being thus turned moves
forward a plug 7, to which is attached an ebony or vulcanite tube 8. the end of
which is inserted an electrode 9 -so that there is no possibility of the current
short circuiting--and as rapidly as the carbon is consumed an additional turn of
the milled head counteracts against this wearing away effect, by bringing the
terminals of the electrodes closer together in order to neutralise the effect of the
carbon addition from the electrodes to the steel I provide sufficient wrought iron
or low carbon steel to balance such an addition to the mass of metal. In order
to prevent the oxidation of the metal I supply the upper crucible furnace with a
sunnly of reducing gas such as Thwaite towns or water gas by means of a
flexible tube 10-this tube is attached to a hollow mounting I passing through
the centre and this mounting I supply a vertical escape tube 12 surmounted with
a regulating cock 13 by which the gas flow escape can be regulated.
This central tube forms with the hollow mounting 11 a circular annular space
by which the reducing gas can enter into the upper crucible and thus prevent the
oxidation of the metal.
The
The negative conductors are shown by 15, the positive ones by 16.
character of current I prefer to use, but of course I do not wish to be confined
to any particular character of current, will be one of high capacity and low
tension, or in other terms of high amperage and low voltage. In order to watch
the progress of fusion, I provide a peephole, covered with a glass or other lens of
suitable colour to neutralise the intensity to a required degree and to permit the
human eye to observe the progress of fusion. This I fix at position 17.
The procedure of operation in dealing with alloys of steel is as follows. The

page_text: eryolite or hydrate of alumina, is intermixed with a special brand of steel and
W. 1. The charge is preferably arranged initially, so as to provide interspaces
between the electrodes, both negative and positive.
The intense heat of the voltaic are and that due to the resistance of the metal,
produces the requisite fusion temperature, and the aluminium in the cryolite, is
reduced and assimilated by the tused mass of metal becoming thoroughly alloyed
with it. The addition of other alloys is effected in a similar manner, that is by
adding an oxide or hydrate of the metal, which is reduced by the carbon of the
steel or that of the electrodes or by the further addition of carbon in a finely
divided condition, that is wherever reduction is required to precede the fusion.
After the metal to be fused has been charged into the crucible, the lid is put
over it, and the reducing gas is turned on. The reducing atmosphere will have a
powerful tendency, not only to reduce any oxidised alloy metal in the charge, but
it will prevent the oxidation of the metal in its high state of fusion. After the
metal is completely fused, the outlet at the bottom of the crucible is opened, and
the metal falls into the lower crucible which has been preliminarily raised to a
high temperature by the Bunsen flame. This lower crucible can then be tilted
by raising the lever of the tilting gear and allowing the metal to flow into the
moulds. After it is emptied the crucible can be returned to its position and a
fresh charge made into the upper crucible and the procedure may be repeated
de noro.
Having now particularly described and nacertained the nature of my said
invention I claim the following as novel features of my invention.
1. The apparatus for effecting the electro fusion of steel.
(2. The employment of a reducing atmosphere in combination with electro-
fusion.
4. The superposed arrangement of crucibles, in which the upper crucible is
the fusion crucible and the lower one is the receiving crucible.
11. The tilting arrangement of the lower tipping crucible.
5. The method of electing the reduction of oxides of the metal for alloying
them with the stes to be produced in combination with the electro-fusion process
substantially described.
(6.) The method of maintaining the under part of the fusion-crucible, and its
tup hole, in a condition of high temperature by electrical methods substantially
described.
(7.) The radial arrangement for applying the positive and negative electrodes
around the circular fusion and reducing vessel, so that they point towards or about
the centre of such vessel, for fusion and reduction purposes substantially as
described.
(8.) The method of holding and regulating the distance between the terminals
and electrodes substantially as shown and described.
(9.) The method of insulating the holder from the electrodes substantially
described.
1201-hassala ماسه سناب لحلم
21st day of December 1909.