IMPROVE- MENTS IN CASTING STEEL
Year: 1864

page_text: LETTERS PATENT to Edmund Leopold Schlesinger Benzon, of Nicholas
Lane, in the City of London, Merchant, for the Invention of "IMPROVE-
MENTS IN CASTING STEEL."-A communication from abroad by Anton
Lohage, of Unna, Westphalia, in the Kingdom of Prussia.
PROVISIONAL SPECIFICATION left by the said Edmund Leopold Schle-
singer Benzon at the Office of the Commissioners of Patents, with his
Petition, on the 2nd November 1864.
I, EDMUND LEOPOLD SCHLESINGER BENZON, of Nicholas Lane, in the City
of London, Merchant, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN CASTING STEEL," to be as follows:-
This Invention has for its object the better preparation of the melted steel
(especially in large masses) before it is poured or allowed to pass into the
moulds or into ingots.
The Invention is applicable to all steel in a molten state, whether uniformly
or thoroughly melted or not, and whether melted by the old method in
crucibles or otherwise, or produced by the Bessemer or other process.
For the purpose of the Invention I employ a furnace lined with fireproof
blocks, made of material of as neutral a character as possible, and made to
fit. The furnace is provided with a moveable funnel made of fireproof
material, through which funnel the molten metal is introduced. The nose of

page_text: the funnel reaches to the bottom of the bed of the furnace or nearly so, and
is in part cut away to allow the metal to flow upon the bottom of the furnace.
The furnace is heated by any well known method, preferring coal or coal gas
in combination with a blast either hot or cold.
I designate that point to which it is necessary to heat all steel for perfect
and sound casting as "overmelted" or "superheated."
The molten steel is conveyed through the funnel, which has been previously
heated, into the furnace, the temperature of which has been raised to about
the melting point of steel. I pour slag into the furnace together with the
steel. The molten metal must be well covered with slag (obtained either
from the melting pots or from the Bessemer process or from previous meltings)
to prevent the flames or the blast from coming in direct contact with the
molten steel. This is essential to the success of the operation. The heat of
the furnace is kept up till the metal is."overmelted" or "superheated," and
has become thoroughly uniform. The metal is then run from the furnace
through one or more tap holes into a receiver or receivers which have been
previously heated, as is well known, and when the metal is quiescent it is
allowed to pass from the receiver into the moulds or into ingots. I con-
tinue the blast both whilst pouring the molten steel into the furnace and
allowing it to run into the receiver or receivers, and this I can do without
injury to the steel by reason of the molten steel being always covered
with slag.
The process above described I call an intermediate process, and by it I am
enabled to gather together in the same furnace and make uniform for one or
more castings or for ingots of cast steel the molten steel, whether-melted in
crucibles or in any other manner, or produced by the Bessemer or other
process.
If the weight of molten steel run into the furnace is sufficient for the
casting, or if the temper of the steel does not require alteration, then the
molten metal need only remain in the intermediate furnace until it is
"overmelted" or "superheated," and the mass has become thoroughly
uniform. If, however, the steel be insufficient in quantity, I add to the
molten mass solid metal (which I prefer to be previously heated), either cast
or wrought iron or blister, puddle, or scrap steel, taking care to maintain the
temper of the steel required for the casting. I alter the temper of the steel
in the intermediate furnace, and make the steel milder by the addition to the
molten mass of wrought iron or slightly carbonized iron. This power of
making the temper of the steel in the furnace milder enables me to melt the
steel in the crucibles (when steel melted in, that way is used) harder than is

page_text: required for the casting, which is an advantage, as it quickens the melting,
and preserves the crucibles. I alter the temper of the steel, and make the
steel in the furnace harder by adding to the mass of molten metal more
highly carbonized solid metal, which I prefer to be previously heated. When
I add solid, that is unmolten metal, to the molten mass in the intermediate
furnace, the process will necessarily take a longer time in the intermediato
furnace before it is ".overmelted." or "superheated," and the mass has become
thoroughly uniform.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Edmund Leopold Schlesinger Benzon in the Great Seal
Patent Office on the 2nd May' 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDMUND
LEOPOLD SCHLESINGER BENZON, of Nicholas Lane, in the City of London,
Merchant, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of November, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Edmund Leopold Schlesinger Benzon, Her special license that I,
the said Edmund Leopold Schlesinger Benzon, my executors, administrators,
and assigns, or such others as I, the said Edmund Leopold Schlesinger Benzon,
my executors, administrators, and assigns, should at any time agree with, and
no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and vend,
within the. United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN CASTING STEEL,"
being a communication from Anton Lohage, of Anna, Westphalia, Prussia,
upon the condition (amongst others) that I, the said Edmund Leopold
Schlesinger Benzon, by an instrument in writing under my hand and seal,'
should particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the saine
to be filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Edmund Leopold Schlesinger Benzon,
do hereby declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained. 'n and

page_text: by the following statement, reference being had to the Drawings hereunto
annexed, and to the letters and figures marked thereon (that is to say) :-
This Invention of "Improvements in Casting Steel" has for its object the
better preparation of the melted steel (especially in large masses) before it is
poured or allowed to pass into the moulds or into ingots.
:
The Invention is applicable to all steel in a molten state, whether uniformly
or thoroughly melted or not, and. whether melted by the old method in
crucibles or otherwise, or produced by the Bessemer or other process, or
partly by one process and partly by the other.
For the purpose of the Invention I employ a furnace lined with fire-proof
-blocks made of material of as neutral a character as possible, the blocks being
made to fit. The furnace is provided with a moveable funnel made of fire-
proof material, through which funnel the molten metal is introduced into the
interior of the furnace, as mentioned in the Specification of the Patent granted
to John Henry Johnson, bearing date Thirty-first of December, One thousand
eight hundred and fifty-eight, No. 3007.
The nose of this funnel reaches to the bottom of the bed of the furnace, or
nearly so, and is in part cut away on the part furthest away from the fire-"
place to allow the metal to flow out therefrom upon the bottom of the furnace.
The furnace is heated by any well known method, preferring coal or coal gas
in combination with a blast, either hot or cold.
I designate that point to which it is necessary to heat all steel in order to
ensure perfect and sound casting as "overmelted" or "superheated."
The molten steel is conveyed through the funnel (which has been previously
heated to a red heat) into the furnace, the temperature of which has been
raised to about the melting point of steel, preferring an excess of that heat to
prevent any cooling of the mass. It is important here to remark that I pour
slag into the furnace together with the steel, or previously melt slag in the
furnace, in order to form a protecting cover for the molten steel. The molten
*metal must be well covered with the slag, which may be obtained either from
the melting pots or from the Bessemer process, or from previous meltings.
This covering of slag is, as is well known, to prevent the flames or the blast
from coming in direct contact with the molten steel, and is essential to the
success of the operation. The heat of the furnace is kept up by means of a
fan or other blast till the metal is "overmelted" or "superheated," and the
whole mass of molten steel has become thoroughly uniform. The metal is
'then run from the furnace through one or more tap holes into a receiver or
receivers which have been previously heated (as is well known), and when
the metal is quiescent it is allowed to pass from the receiver into the moulds

page_text: or into ingots. I continue the blast whilst pouring the molten steel into the.
furnace whilst it is in the furnace, and whilst allowing it to run into the
receiver or receivers, so as to keep it "overmelted" or "superheated," and
this I can do without injury to the steel by reason of the molten steel being
always covered with slag.
The process above described I call an intermediate process, and by it I am
enabled to gather together in the same furnace molten steel (whether
uniformly or thoroughly melted or not, and whether melted in crucibles or in
any other manner, or produced by the Bessemer or other process, or partly by
one process and partly by the other,) and make the same uniform for one or
more castings, or for forming ingots of cast steel, by continuing the melting
process till the mass is "overmelted" or "superheated," thus enabling me to
make castings of larger size, and several castings or ingots of more equal
temper than heretofore.
If the weight of molten steel run into the intermediate furnace is sufficient
for the casting intended to be made, or if the temper of the steel does not
require alteration, then the process need only be continued until it is "over-
melted" or "superheated," and the mass has become thoroughly uniform.
The usual experience of a steel melter which tells him when the steel in
crucibles is sufficiently melted for the purpose of casting, will enable him to
ascertain when the mass in the intermediate furnace is "overmelted" or:
"superheated." I can also test the heat by inserting a rod of wrought iron,
and the rapidity of the action of the molten steel on the rod will shew the
practical melter when the mass is ready for pouring. If, however, the steel
be insufficient in quantity, I add to the molten mass solid metal (which
I prefer to be previously heated), either cast or wrought iron or blister puddled
or scrap steel, taking care to maintain the temper of the steel required for.
the casting. I alter the temper of the steel in the intermediate furnace, and
make the steel milder by the addition to the molten mass of wrought iron or.
slightly carbonized iron, which I prefer to be previously heated. This power
of making the temper of the steel in the intermediate furnace milder enables.
me to melt the steel in the crucibles (when steel melted in that way is
used wholly or in part) harder than is required for the casting, which is an
advantage, as it quickens the melting, and prevents the crucibles from being
prematurely destroyed. I also alter the temper of the steel, and make the
steel in the intermediate furnace harder by adding to the mass of molten
metal more highly carbonized solid metal, which I prefer to be previously
heated. When I add solid, that is, unmolten metal, to the molten mass in
the intermediate furnace (and which I prefer to add gradually and not

page_text: altogether) the process will necessarily take a longer time in the intermediate'
furnace before the steel is "overmelted" or "superheated," and the mass has
become thoroughly uniform.
***
When it is desired to add spiegel eisen to the molten metal, as 'proposed by
Mr. Musbet, I prefer to add it to the mass in the intermediate furnace instead 5
of in the Bessemer converting vessel, as heretofore practised.
In all cases the process must be continued till the molten steel and the steel'
or iron added in the intermediate furnace is "overmelted" or "superheated,"
and the mass has become uniform. The practical experience of steel melters'
will enable the operator to determine when the steel is ready for pouring..
. When I operate on crucible melted steel only, I prefer to have the top of
the intermediate furnace on a level with the floor of the melting house. It is
not, however, necessary to shew this arrangement by Drawings.
.
:
When I operate on Bessemer steel, either alone or in conjunction with
crucible melted steel, I prefer to arrange the works specially for the purpose. 1
The intermediate process in all cases softens the steel slightly, which allows
me, even if I intend no alteration of temper in the intermediate furnace, to
melt the steel in the crucibles harder in the first instance, which is an
advantage.
In the accompanying Drawings I have shewn the furnace for carrying out
my intermediate process, which, however, may be varied in form, and also the
plan I prefer for adapting my Invention to steel works in which the Bessemer
process for making steel is employed.
Figure 1, Sheet I. is a sectional elevation of a pair of Bessemer converting
vessels B, B, conveniently arranged for the purposes of my Invention. It will
be seen that between the two vessels is placed a crane A, provided with a
receiving vessel C, into which the Bessemer metal is poured for the purpose
of conveying it to the intermediate furnace, which is shewn in longitudinal
vertical section at Figure 2.
Figure 3 is a transverse vertical section, shewing the Bessemer converting
vessel B, and the crane A, with the receiving vessel C, from which the molten
metal is being discharged into the intermediate furnace D. This Figure also
shews another crane E, with another and larger receiving vessel F, into which
the molten steel is run out from the intermediate furnace D, and is conveyed
by the crane E to the mould G to form the casting. The vessels C and F
should be heated before being used, as is well understood.
Figure 4 is a plan view of the whole arrangement, the intermediate furnace
being shewn in section; Figure 5 is an end view of the furnace; and Figure 6 is
a transverse vertical section of the same, shewing the large receiving vessel F;

page_text: placed ready to receive a charge of molten steel from the furnace D. The
intermediate furnace D is built so far below the floor of the steel melting'
house, that the top of the furnace coincides with the floor of the former. The
pits H, to receive the mould G, are placed convenient to the furnace, and
suitable foundations for cranes are also placed beneath the level of the floor of
the melting house, as shewn in the Drawing.
.
In order to prepare the intermediate furnaco for working, I commence by
heating the furnace by the fuel in the fire-place, to which end I open the'
doors a, Figures 2 and 5, and by the natural 'draft thus obtained I bring up the
heat to what I term "almost a white heat." In order to afterwards increase
the heat I close the doors a and open the valve b, Figures 2 and 5, in the blast
conduit pipe. The blast is thus driven under the fire-bars by means of a fan
or cylinder blast, and causes a very active combustion of the fuel, and the
heat in the furnace is thereby much increased. In order to increase the heat
still more, and to burn more completely all the gases (arising from the fuel)
two openings c, c, are made above the fire bridge, as seen in Figures 2 and 4.
A blast from any convenient source is made to pass through these openings,'
which are controlled by suitable stop-cocks. When I want to rake the fire to
clear the fire-bars or to supply coals to the fire-place, the valve 6 must be
closed and the door a opened. The molten metal from the receiver C is'
poured into the intermediate furnace through the funnel d, which must be
inade red hot in a suitable oven before it is put into its place in the furnace,
where it should be placed about fifteen minutes before it is required to be used.'
The molten steel is poured into the intermediate furnace through the
funnel d, and after the necessary quantity of metal is in the furnace the funnel
is removed, and the opening in the roof is closed by a removeble lid or stopper.'
Before filling the furnace with steel, any cinder or other impurities which
may have accumulated in it must be removed. Should any slag get into the
exit Blue e of the furnace, it is removed through the opening h. When the
steel is ready for casting, the furnace is tapped at 9, 9; and I prefer to provide'
two or more tap holes (two are shewn in the Drawings), so that if it should be
found desirable not to run off the whole charge of molten metal at one'
operation, the tap hole or holes that has or have been used may be plugged'
up temporarily with fire-clay; and as a tap hole that has been used cannot
readily be reopened in the same place, another tap hole or other tap holes
may be employed for running out the remainder of the charge.
In order to operate upon steel melted in the ordinary crucibles or other
melting furnaces, I simply pour the contents of each crucible through the
:

page_text: funnel d into the intermediate furnace, or I gather the contents of several
crucibles in a receiver previously heated, and then empty that receiver into
the intermediate furnace.
After the Bessemer process has been completed in the converting vessels,
I empty the contents of the converter into the receiver C, held by the crane A,
as shewn in Fig. 1. The crane is then raised by means of hydraulic power,
as is well known, and the, receiver C is brought round over the funnel d of the
intermediate furnace. The plug c of the receiver C is then drawn up, and
the receiver empties itself into the furnace, as shewn at Fig. 3. After the
steel has been subjected to the required degree of heat in the intermediate
furnace until it is "overmelted" or "superheated," it is allowed to flow
through the tap holes g into the large receiver F, which is held by the crane E.,
When this receiver is brought over the mould G placed in the pit H, Fig. 3,
the steel is allowed to flow into the mould, as already explained.
When it is desired to add to the steel coming from the Bessemer converting
vessels, steel melted in ordinary crucibles, either for the purpose of improving
the quality or of increasing the quantity of the mass, the crucible melted steel
may be poured by single crucibles or from a receiver into the intermediate
furnace through the funnel d, either before or after the Bessemer steel has
been poured into the intermediate furnace.
I can successively pour into my intermediate furnace the contents of two to
four or even more of the Bessemer converting vessels, according to the
capacity of the furnace, and the construction of the steel works. The molten.
steel may remain half an hour or longer in the intermediate furnace, and in so
long a time it is practicable to make a second conversion in the Bessemer
converting vessels, and this extra quantity can be added to the first in the
furnace.
If it be desired to obtain access to the under side of the fire bars while the
furnace is in operation, this must be done from the ash-pit I in the air
channel, to which there are two doors f and f, fitted air-tight, as shown in
Fig. 2. The fireman enters through the door f, and then closes the same, and
opens a slide or valve i of the second door f¹, in order to counterbalance or
equalize the pressure of air, after which the door f¹ may be opened. On
returning, the fireman closes the door f, and opens the slide i of the door f.
The compressed air in the space between the two doors will then escape, and
the doorf may be opened.
I would have it understood that I do not claim the particular furnace
and accessories to the same herein-before described, and shewn in the

page_text: Drawings, nor do I claim the special arrangement of the works herein-before
described, and shewn in the Drawings; but what I do claim under the
herein-before in part recited Letters Patent is as follows, that is to say:-
First, the process herein-before described, and called an intermediate
process, whereby I continue the melting process till the mass is "overmelted"
or "superheated," made uniform, and ready for casting.
Second, the modes herein-before described of altering the temper of the
molten steel in the intermediate process.
In witness whereof, I, the said Edmund Leopold Schlesinger Benson,
have hereunto set my hand and seal, the Twenty-third day of April,
in the year of our Lord One thousand eight hundred and sixty-five.
E. L. S. BENZON Gal