IMPROVE- MENTS IN THE MANUFACTURE OF IRON AND STEEL AND IN FURNACES AND APPARATUS FOR THAT PURPOSE
Year: 1877

page_text: LETTERS PATENT to Charles William Siemens of No. 12 Queen Anne's Gate
Westminster in the County of Middlesex for an Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF IRON AND STEEL AND IN FURNACES AND
APPARATUS FOR THAT PURPOSE
"
PROVISIONAL SPECIFICATION left by the said Charles William Siemens
at the Office of the Commissioners of Patents on the 5th September 1877.
CHARLES WILLIAM SIEMENS of No. 12 Queen Anne's Gate Westminster in the
County of Middlesex "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
AND IN FURNACES AND APPARATUS FOR THAT PURPOSE
"
According to my invention I prepare an intimate mixture of comparatively rich
iron ores and orides such as hammer or roll scale, of fluxes such as lime, alumina
manganese and soda, or of ironstone containing these earths, and of reducing
agents such as anthracite, charcoal coke or common coal, employing these sub-
stances in such proportions that the fluxing materials (when acted upon by intense
heat) form a fusible slag taking up only a moderate proportion of ferrous oxide
from the ores and that the carbonaceous matter suffices for the reduction of the
bulk of the ferrous and ferric oxides into metallic iron. This intimate admixture of
materials is conveniently effected by means of the apparatus well known as Carr's
Disintegrator, into which the materials are fed continuously by means of several
feeding belts or Jacob's ladders, each of which is made to supply one of the
several ingredients in its proper proportion, the materials being crushed and mixed
intimately in passing through the apparatus. The mixture or "Batch so prepared
is stored upon an elevated platform near the furnaces to be employed for effecting
its conversion into Steel or iron.
"
The furnace I employ for the production of cast steel from the "batch" so
prepared is similar in construction to the well known Regenerative gas furnace for
the production of Steel upon the open hearth as described in my former Patents.
A good silica bottom having been prepared in this furnace in the usual manner and
the heat of the furnace having being raised to whiteness, from one to two hundred-
weight of crushed anthracite or coke is spread over the bottom and sides of the
heated chamber, whereupon a charge of "batch "-from three to six tons or more

page_text: according to the dimensions of the furnace, is introduced and spread uniformly over
the furnace bottom, forming a considerable thickness. This batch" may be
conveniently introduced into the furnace doors through inclined shoots reaching
up to the elevated charging platform above referred to, which shoots are removed
after each charge is completed. The furnace doors being closed intense heat is
allowed to act upon the surface of the mixture for several hours, the effect of
which is that a thick skin of compact metallic iron is formed containing only an
admixture of fluid slag which serves to protect the metal against the oxidising
and sulphurising action of the flame. Pig metal in variable proportions is now
introduced by preference in a heated condition, which upon melting dissolves the
skin of metallic iron upon which it is bedded, and thus produces a fluid metallic
bath which gradually incorporates with itself all the ore mixture or "batch" within
the furnace excepting the reducing agent, which is volatilised, and the earth
constituents, which form a slag floating upon the metallic surface. This latter
may be partly or wholly withdrawn through the working doors if found to be
excessive in amount. If in taking a sample of the metal it is found to contain an
excess of carbon, raw ore or oxide may be introduced which will reduce the same
to the desired percentage. Or if scrap wrought metal is available, this may be
used to reduce the percentage of carbon in the fluid metal while adding to the
bulk of the latter. When a sample taken from the bath gives the desired test for
carbon, Spiegeleisen or Ferromanganese is added in the usual proportion and the
fluid metal is withdrawn by tapping the furnace, and poured into ingot or other
moulds according to the usual practice. Silicon iron is also added shortly before
the Spiegeleisen or Ferromanganese in order to produce sound castings.
If light scrap such as turnings or cuttings of iron or steel is available this may
be mixed conveniently with the "batch" and thus add to the metallic bath produced.
Or granulated pig metal may be used with the batch in which case fusion will readily
ensue without any further addition of pigmetal.
If it is intended to produce wrought iron I charge a mixture or "batch" as above
described into a heated regenerative Gas furnace conveniently arranged for gaining
access to the same, and when a metallic skin has been formed I remove the same
by means of hooks and pass it through a pair of rolls placed about half an inch
apart. In passing through these rolls a considerable proportion of the cinder
mixed with the iron is separated and a rough plate is produced which is cut up
into small pieces by means of shears. These are transferred to charcoal hearths or
hollow fires where they are massed together and hammered to be subsequently
rolled into merchant bars or plate in the usual manner. Iron of great purity is
thus produced which will take the place of Swedish or charcoal bar for the
production of tool steel or tin plate and for other purposes-When one skin has
been removed from the surface of a charge of "batch" in the furnace the doors are
again closed and a second similar metallic skin is formed and removed, and this
process may be repeated several times before additional mixture or "batch" is
introduced into the furnace. If comparatively poor ores are used fluid slag will
accumulate in the furnace which has to be removed by tapping from time to time.
In this case it will be found advisable to form the sides of the heated chamber of a
fettling compound of solid carbon such as anthracite or coke dust with clay, and
to clear the furnace entirely of metal and slag before giving a fresh charge of
mixture or "batch." The "batch" may in this case also be mixed with light scrap
metal or granulated pig-metal to increase the yield per day of each furnace

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Charles William Siemens in the Great Seal Patent Office on the
4th March 1878.
CHARLES WILLIAM SIEMENS of N° 12 Queens Anne's Gate Westminster in the
County of Middlesex "IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
AND IN FURNACES AND APPARATUS FOR THAT PURPOSE
""
According of my invention I prepare an intimate mixture of comparatively rich
iron ores and oxides such as hammer or roll scale, of fluxes such as lime, alumina
manganese and soda, or of ironstone containing these substances, and of reducing
agents such as anthracite, charcoal coke or common coal, employing these substances
in such proportions that the fluxing materials (when acted upon by intense heat)
form a fusible slag taking up only a moderate proportion of ferrous oxide from the
ores and that the carbonaceous matter suffices for the reduction of the bulk of the
ferrous and ferric oxides into metallic iron. This intimate admixture of materials
is conveniently effected by means of the apparatus well known as Carr's Disin-
tegrator, into which the materials are fed continuously by means of several feeding
belts or Jacob's ladders, each of which is made to supply one of the several ingredients
in its proper proportion, the materials being crushed and mixed intimately in passing
through the apparatus. The mixture or Batch" so prepared is stored upon an
elevated platform near the furnaces to be employed for effecting its conversion into
steel or iron.
"
"
SQ
The furnace I employ for the production of cast steel from the "batch'
prepared is similar in construction to the well known Regenerative gas furnace for
the production of steel upon the open hearth as described in the Specifications of
Patents previously granted to me. A good silica bottom having been prepared in
this furnace in the usual manner and the heat of the furnace having been raised to
whiteness, from one to two hundredweight of crushed anthracite or coke is spread
over the bottom and sides of the heated chamber, whereupon a charge of "batch"
from three to four tons or more according to the dimensions of the furnace, is
introduced by preference in several separate charges at short intervals and spread
uniformly over the furnace bottom, forming a considerable thickness. This "batch
may be conveniently introduced into the furnace doors through inclined shoots
reaching up to the elevated charging platform above referred to, which shoots are
removed after each charge is completed. The furnace doors being closed, intense
heat is allowed to act upon the surface of the mixture for several hours, the effect of
which is that a thick skin of compact metallic iron is formed containing only an
admixture of fluid slag which serves to protect the metal against the oxidising and
sulphurising action of the flame. Pig metal in variable proportions is now introduced
by preference in a heated condition, which upon melting dissolves the skin of metallic
iron upon which it is bedded, and thus produces a fluid metallic bath which
gradually incorporates with itself all the ore mixture or batch" within the
furnace excepting the reducing agent, which is volatilised, and the earthy
constituents, which form a slag floating upon the metallic surface. This latter
may be partly or wholly withdrawn through the working doors if found to be
excessive in amount. If, in taking a sample of the metal, it is found to contain an
excess of carbon, raw ore or oxide may be introduced which will reduce the same
to the desired percentage. Or if scrap wrought metal is available, this may be
used to reduce the percentage of carbon in the duid metal while adding to the bulk
of the latter. When a sample taken from the bath gives the desired test for
carbon, Spiegeleisen or Ferroin unganese is added in the usual proportion and the
fluid metal is withdrawn by tapping the furnace, and poured into ingot or other
11818.-2. Wt. 23570.
"

page_text: "
moulds according to the usual practice. Silicon iron may be also added shortly
before the Spiegeleisen or ferromanganese in order to produce sound castings. If
light scrap such as turnings or cuttings of iron or steel, is available, this may be
mixed conveniently with the "batch and thus add to the metallic bath produced.
Or granulated pig metal may be used with the "batch," in which case fusion will
readily ensue without any further addition of pig metal. When large scrap metal
is available, the furnace may be charged in the first instance with a mixture of
"batch and small iron or steel scrap such as turnings, borings or punchings.
This mixture being spread over the bottom forms a fettling thereon protecting the
silica of the bed from the corrosive action of iron oxide. Upon this, pig metal and
large scrap such as broken iron or steel rails may be introduced in the proportion of 2
of pig metal to 5 of scrap or thereabout After fusion of the whole charge and its
decarburisation so far as required, Ferromanganese or Spiegeleisen is added. If
the iron rails contain phosphorus the mixture of materials should be such that the
resulting metal shall contain by preference 2 to 25 per cent of Phosphorus, and
the amount of Ferromanganese added on tapping the furnace should be such that
the metal shall contain from 75 to 10 per cent of metallic Manganese without more
than 2 per cent of carbon.
"
دو
If it is intended to produce wrought iron I charge a mixture or batch as above
described into a heated regenerative gas furnace conveniently arranged for gaining
access to the same, and when a metallic skin has been formed I remove the same
by means of hooks and pass it through a pair of rolls placed about half an inch
apart. In passing through these rolls a considerable proportion of the cinder mixed
with the iron is separated and a rough plate is produced which forms a suitable
melting material for the production of cast steel or which may be cut up into small
pieces by means of shears. These are transferred to charcoal hearths or hollow fires
where they are massed together and hammered to be subsequently rolled into
merchant bars or plate in the usual manner. Iron of great purity is thus produced
which will take the place of Swedish or charcoal bar for the production of tool steel
or tin plate and for other purposes. When one skin has been removed from the
surface of a charge of "batch" in the furnace, the doors are again closed and a
second similar metallic skin is formed and removed, and this process may be
repeated several times before additional mixture or "batch" is introduced into the
furnace. If comparatively poor ores are used, fluid slag will accumulate in the
furnace which has to be removed by tapping from time to time. In this case it
will be found advisable to form the sides of the heated chamber of a fettling
compound of solid carbon such as anthracite or coke dust with clay, and to clear
the furnace entirely of metal and slag before giving a fresh charge of mixture or
'batch." The "batch" may in this case also be mixed with light scrap metal or
granulated pig-metal to increase the yield per day of each furnace.
"
In the accompanying sheet of Drawings Figs 1, 2 and 3 shew a construction of
regenerative gas furnace suitable for operating in the manner described above, Fig 1
representing a section on the line X X on Fig 2 which is a plan, the upper half
taken at the level Y Y on Fig 1 and the lower half on the level Y¹ Y on Fig 1. A
part longitudinal section on Z Z (Fig 1) is shewn at Fig 3. In these Figures A is
the bed of the furnace behind which are placed the two pairs of regenerative
chambers, B, B₁ alternately employed for heating the air and C, C¹ for alternately
heating the gas supplied to the furnace. These regenerators communicate with
the furnace by throats 6 6¹ for the air, and c c' for the gas. While the air and gas
are heated in their passage through the one pair of regenerators and form the
flame in the furnace, the products of combustion pass through the other pair of
regenerators beating them; this action being alternated by valves arranged in the
usual way. Fig 4 represents a section of a furnace, which may be a regenerative
gas furnace, with an arrangement for conveniently running the metal into a set of
ingot moulds fed at the bottom from a git; Fig 5 is a plan of this arrangement.
G is the git communicating at its bottom by runner pipes with a number of
ingot moulds I I. The funnel mouth H of the git G is extended over a surplus

page_text: mould K into which the extra metal runs when the ingot moulds have been
fully charged. A removeable spout S which may be swung into or from its place
by overhead pullies P conducts the metal from the tap hole of the furnace F to the
git G.
Having thus described the nature of my invention and in what manner the saine
is to be performed I clain :-
to the
First. The process, substantially as herein described, for producing cast steel, that
is to say, preparing a " batch " or intimate mixture of rich iron ore or oxide,
alkaline flux and carbonaceous reducing agent, subjecting the said "batch
intense heat of a Regenerative Gas Furnace for reduction of the same and fusion
of the slag, adding pig metal, also ore or wrought iron or steel scrap and finally
Manganiferous iron.
Second. In operating according to the process above referred to, using "batch" by
preference mixed with light iron or steel scrap in such proportion only to the total
charge of the furnace as to constitute a protecting lining for the bottom, and making
up the charge mainly by means of large scrap and pig metal substantially as herein
described.
Third. The process substantially as herein described, for producing malleable iron,
that is to say, preparing a "batch" or intimate mixture of iron ore or oxide
alkaline flux and carbonaceous reducing agent, subjecting the said " batch to the
intense heat of a Regenerative Gas Furnace till a skin of iron is formed thereon,
removing the said skin and rolling it into rough plate to be transferred into a steel
melting furnace, or to be cut into pieces and fagotted for the production of Merchant
bars or plates.
In Witness whereof I the said Charles William Siemens have hereunto set my
hand and seal this Second day of March in the year of our Lord One thousand
eight hundred and seventy eight.
Witness:
JNO A HEAD
12, Queen Anne's Gate
London S.W.
C WILLIAM SIEMENS (L.S.)