IMPROVEMENTS IN THE MANUFACTURE OF STEEL, AND IN APPARATUS EMPLOYED THEREIN
Year: 1879

page_text: LETTERS PATENT to John Clayton Mewburn, of 169, Fleet Street, in the
City of London, Patent Agent and Consulting Engineer, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF STEEL, AND IN APPARATUS
EMPLOYED THEREIN." A communication from abroad by La Société Français
des Aciers of Paris France.
"
aled the 1st July 1879, and dated the 29th March 1879.
PROVISIONAL SPECIFICATION left by the said John Clayton Mewburn at
the Office of the Commissioners of Patents on the 29th March 1879.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London,
Patent Agent and Consulting Engineer. "IMPROVEMENTS IN THE MANUFACTURE
OF STEEL, AND IN APPARATUS EMPLOYED THEREIN." [A communication from abroad
by La Société Français des Aciers, of Paris, France.]
The improvements which form the subject of the present Invention have for
object the production of steel in the chemically pure state of nitro-carburet of iron
and comprise various new processes for producing the desired results, and also new
apparatus for carrying out these processes.
In order to produce a quality of steel always uniform suitable for different changes
with regard to special uses I proceed in the first place without puddling and before
the fusion of the metal to remove injurious metalloids and excess of carbon con-
tained in the first or raw materials, Bessemer metal, scraps from various sources,
cast iron, etc., I thus avoid a repeated and necessarily irregular mixture or dosing of
the raw materials intended to be transformed into steel. This purification is effected
by means of a current of hydrogenated carbonic acid passing over the metals to be
transformed raised to a temperature of 1020° to 1110° Fahrenheit. The carbonic
acid removes the metalloids and the excess of carbon by becoming transformed into
dento-carbonated sulphurous, phosphorus, or arsenious oxide gas, according to whether
the materials operated upon contain sulphur, phosphorus, or arsenic. The metals
having been thus prepared the operation is continued by fusion by means of a
special furnace heated with oxide of carbon in which the Bessemer rails or bars are
placed after a previous cementation in apparatus adjoining the furnace, and herein-
after described; then the product resulting from the fusion is refined by a determined
injection of carbonic acid and nitrogen, either simultaneously or alternately.

page_text: When it is desired to produce cemented steel, either to be utilized directly or to
be mixed with cast iron, to produce cast steel I make the iron bars to be cemented
chemically pure by the process above mentioned, then the transformation into steel
is produced in cementing furnaces with continuous fire of suitable arrangement and
form and working at a low temperature.
The following considerations have led to the adoption of cementing furnaces with
continuous fire. In ordinary cementing furnaces a chemical phemomenon is pro-
duced, viz,The furnace becoming heated very slowly after charging the carbon
contained in the cementing troughs or boxes becomes dry gradually by vaporizing
the hygrometric water and the finest parts of the carbon, so that when the iron to
be cemented acquires the temperature at which these gases can produce a reaction
in its molecules the cement is deprived of its essential cementing elements hydrogen,
nitrogen, and so to speak, the essence of the carbon. Hence grave incoveniences are
caused; the very slow carburation and at a low temperature of the surfaces of the
iron to be cemented; this carburation takes place only for a very slight thickness
of the metal; the necessity of heating vigorously and of attaining a temperature of
more than 2000° in order to gasefy the carbon previously deprived of nitrogen and
hydrogen which disorganizes the arrangement of the molecules of the surface of the
iron owing to the dilatation; lastly, the difficulty which the new cementing gases
produced at this too high temperature have in penetrating into the body of the iron,
the surfaces having already their pores closed by the combined action of the carbon,
nitrogen, and hydrogen.
The nitrogen and hydrogen disengaged by the cement are generally in too slight
proportions in comparison with the carbonic acid. In order to remedy this I revivify
the cement during the operation by means of intermittent injections of nitrogen
and hydrogen gases, which serve as a vehicle to the carbon in the pores of the
metal.
These considerations have led to the addition to the furnace intended for the
fusion or melting of the steel of two other furnaces which I will call preparing
and finishing furnaces.
I can also use separately, while adopting the same principles, a cementing furnace
with continuous fire deprived of its melting furnace for treating directly iron bars,
old Bessemer or other rails, intended after cementation either for immediate indus-
trial use or for melting in the melting furnace. This arrangement is hereinafter
referred to.
The furnace is composed of three principal parts; first, the preparing furnace for
the original material; secondly, a melting chamber; and thirdly, the finishing fur-
nace for the refining of the steel obtained by melting. The furnace is fed from a
suitable gas holder. The oxide of carbon produced by the gas generator is conducted
by channels into a chamber; from this chamber the oxide of carbon passes through
a number of flues made in the thickness of the arch of the melting furnace and
extending into another chamber at the back in which the oxide of carbon becomes
combined with atmospheric air. This air enters a channel through a grated opening
made in the front of the furnace and passes along this channel and under the furnace
until it reaches a chamber below the oxide of carbon chamber. It afterwards passes
from this chamber through a number of flues into the upper chamber, where it
combines with the oxide of carbon. These two gases thus combined can be ignited
in the chamber, and the current of the flames after having heated the melted furnace
follows a channel which leads it into a compartment under the preparing and
finishing furnace. In this compartment the flames divide into four branches and
issue respectively by two sets of six flues at. the right, and two other sets at the left,
after having heated the lower arches of this furnace. In rising into a middle com-
partment a portion of these flames beats the vertical sides of the channels through
which the oxide of carbon and the atmospheric air pass, and these become heated
therein and acquire a temperature of about 300°. Another portion of the flames in
rising to the middle compartment heats the vertical sides of the compartments of
the finishing furnace, in which are two cementing troughs, while in the middle

page_text: compartment the flames heat the top of the cementing troughs and also the under-
side of retorts and a heater, hereinafter described; then they pass into an upper
compartment by flues at the right and left; they thus heat the top of the retorts
and the sides of the said heater, and then they escape by passages into a flue
from which the gases arising from the combustion are conducted into a suitable
chimney.
The retorts are intended to receive the first or raw materials (cast iron or Bessemer
metal) which it is wished to purify and deprive of injurious metalloids. For this
purpose I can either previously introduce into the retort a layer of carbonate of lime
in lumps with two to three per cent. of small coal (houille menue) on which layer
the material to be operated upon is placed, or after having enclosed the metal in
the retort I can pass into it a current of hydrogenated carbonic acid.
These retorts having been charged, closed by a luted cover, and heated to a
temperature of 1020° to 1110° the carbonate is transformed into lime, and disengages
carbonic acid gas and hydrogen which react on the metal; the sulphur, phosphorus,
or arsenic, as well as the carbon in excess are absorbed by the carbonic acid and
pass into the upper compartment before referred to by two orifices formed in the
retorts for the purpose, and thence into the chimney with the combustion gases.
The hydrogen on the contrary penetrates the pores of the metal and finds its way
between the molecules, thus causing a sort of intermolecular' washing. It is well
not to exceed the temperature of 1110° because beyond this the hydrogen unites
with the metalloids and retains them in the pores of the metal.
This first operation lasts about 8 hours.
The cast iron having passed into the preparing furnace is still hot and is put
into the melting furnace. The Bessemer metal on leaving the preparing furnace is
first placed in a cementing trough and covered with a cement thus composed:
Carbonized peat
-
Small caking or fat coal (houille grasse menue)
Carbonate of lime
4 parts.
1 part.
2 per cent.
This metal submitted to cementation for ten or twelve hours is withdrawn from
the troughs and ready to be put into the furnace with the cast iron. The cast iron
and the Bessemer metal mixed by the melting and stirring are run after 8 hours
heating into ingot moulds on a revolving plate.
The steel thus obtained is as it were a raw material which can be transformed
into any desired quality by means of the refining or finishing furnace.
This refining furnace is composed of two cementing troughs into which there is
placed according to the quality of steel desired dry peat with 1/4 washed and
desulphurized coal and two per cent. of carbonate of lime to produce mild fibrous
steel with ordinary grains, or carbonized peat with one part of small coal (houille
menue) and two per cent. of carbonate of lime to obtain a harder fibrous steel with
closer grains, or carbonized peat with '/, small coal (houille menue) and two per
cent. of carbonate of lime to obtain very hard fibrous steel with microscopic grains.
This cementing furnace with continuous flame presents no difficulty in charging
and discharging, the troughs containing the metals to be cemented being movable
and made to slide or roll.
The refining is effected as follows:-The heater before referred to is full of iron
or copper waste and cuttings and is intended for the production of nitrogen.
Atmospheric air slightly moist and a little compressed in a suitable holder is
injected into a pipe; this pipe passes through the flames of the furnace so that the
air becomes heated and it afterwards enters the heater by small pipes. The cuttings
and waste in the heater being beated to a dull red, oxidize in the passage of the
atmospheric air from the said pipe, this air passing through the whole layer, and
the nitrogen set free rises to the upper part of the heater from which it is conducted
by pipes, arranged as hereinafter explained, into the cementing troughs; cocks on
one of these pipes allow of nitrogen and hydrogen being sent into the troughs at
intervals. Opposite each cementing trough is a branch pipe at right angles to the

page_text: main pipe and in communication therewith. This pipe rises vertically and stops
at the base or bed of the cementing furnace where a small damper allows of closing
the aperture during the manipulation of the troughs. In each trough is fixed at
the bottom a horizontal tube formed with small holes throughout its length, at one
of its ends is a vertical pipe for putting it into communication with the pipe by
which the nitrogen is supplied. In the vertical pipe is fitted a movable pipe
slightly conical at its lower end, and easily raised or lowered by means of a rod and
lever. When it is required to remove the trough from the furnace the lever is
pressed down, the movable pipe rises, and the trough being thus clear of all
obstruction can be withdrawn. The returning of the trough to position is effected
in the same manner.
The arrangement, hereinbefore referred to, of cementing furnace without a melting
furnace, differs from that already described only in the absence of the melting
furnace, and the arrangement of the heating channels and of the fire place required
for direct heating by a suitable fuel. This heating may be effected as before with
oxide of carbon. The arrangement includes the cementing troughs and heater
previously described for supplying nitrogen, these being put into communication by
the same arrangement of pipes.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Clayton Mewburn in the Great Seal Patent Office on the
9th July 1879.
JOHN CLAYTON MEWBURN, of 169, Fleet Street, in the City of London,
Patent Agent and Consulting Engineer. "IMPROVEMENTS IN THE MANUFACTURE
OF STEEL, AND IN APPARATUS EMPLOYED THEREIN." A communication from abroad
by La Société Français des Aciers, of Paris, France.
The improvements which form the subject of the present Invention have for
object the production of steel in the chemically pure state of nitro-carburet of iron,
and comprise new processes for producing the desired results, and also new
apparatus for carrying out these processes.
In order to produce a quality of steel always uniform suitable for different
changes with regard to special uses, I proceed, in the first place, without puddling
and before the fusion of the metal, to remove injurious metalloids and excess of
carbon contained in the first or raw materials, Bessemer metal, scraps from various
sources, cast iron, &c.; I thus avoid a repeated and necessarily irregular mixture or
dosing of the raw materials intended to be transformed into steel. This purification
is effected by means of a current of hydrogenated carbonic acid passing over
the metals to be transformed raised to a temperature of 1,020° to 1,110°
Fahrenheit. The carbonic acid removes the metalloids and the excess of carbon by
becoming transformed into dento-carbonated sulphurous, phosphorous, or arsenious
oxide gas, according to whether the materials operated upon contain sulphur,
phosphorus, or arsenic. The metals having been thus prepared the operation is
continued by fusion by means of a special furnace heated with oxide of carbon, in
which the Bessemer rails or bars are placed after a previous cementation in appa-
ratus adjoining the furnace and hereinafter described; then the product resulting
from the fusion is refined by a determined injection of carbonic acid and nitrogen
either simultaneously or alternately.
When it is desired to produce cemented steel, either to be utilized directly or to
be mixed with cast iron to produce cast steel, I make the iron bars to be cemented
chemically pure by the process above mentioned; then the transformation into steel
is produced in cementing furnaces with continuous fire of suitable arrangement and
form, and working at a low temperature.
The following considerations have led to the adoption of cementing furnaces with
continuous fire. In ordinary cementing furnaces a chemical phenomenon is pro-
duced, viz. The furnace becoming heated very slowly after charging the carbon
contained in the cementing troughs or boxes becomes dry gradually by vaporizing
the hygrometric water and the finest parts of the carbon, so that when the iron to
be cemented acquires the temperature at which these gases can produce a reaction
in its molecules the cement is deprived of its essential cementing elements, hydrogen,
nitrogen, and, so to speak, the essence of the carbon. Hence grave inconveniences
are caused-The very slow carburation, and at a low temperature, of the surfaces
of the iron to be cemented; this carburation takes place only for a very slight
thickness of the metal; the necessity of heating vigorously and of attaining a
temperature of more than 2,000° in order to gasefy the carbon previously
deprived of nitrogen and hydrogen, which disorganizes the arrangement of the
molecules of the surface of the iron owing to the dilatation; lastly, the difficulty
which the new cementing gases produced at this too high temperature have in
penetrating into the body of the iron, the surfaces having already their pores closed
by the combined action of the carbon, nitrogen, and hydrogen.
The nitrogen and hydrogen disengaged by the cement are generally in too slight
proportions in comparison with the carbonic acid; in order to remedy this I
revivify the cement during the operation by means of intermittent injections of
nitrogen and hydrogen gases, which serve as a vehicle to the carbon in the pores of
the metal,

page_text: These considerations have led to the addition to the furnace intended for the
fusion or melting of the steel of two other furnaces, which I will call preparing
and finishing furnaces. They are represented in Sheet 1 of the annexed Drawings.
I can also use separately while adopting the same principles a cementing furnace,
represented in Sheet 2, with continuous fire deprived of its melting furnace for
treating directly iron bars, old Bessemer or other rails intended after cementation
either for immediate industrial use or for melting in the melting furnace. This
arrangement is hereinafter referred to.
The furnace represented in Sheet 1 is composed of 3 principal parts; first, the
preparing furnace for the original material; secondly, a melting chamber; and,
thirdly, the finishing furnace for the refining of the steel obtained by melting.
Figure 1 is a sectional plan of the whole furnace, and Figure 2 a longitudinal
section; Figures 3 and 4 are transverse sections. The furnace is fed from a suitable
gas holder. The oxide of carbon produced by the gas generator is conducted by a
channel into the flue C, and by channels C2, C3, C2, into a chamber C3; from this
chamber the oxide of carbon passes through a number of flues C made in the
thickness of the arch of the melting furnace and extending into the chamber C³ in
which the oxide of carbon becomes combined with atmospheric air; this air enters
a channel D through a grated opening made in the front of the furnace, and passes
along this channel into a chamber D'; it afterwards passes from this chamber
through a number of flues into the upper chamber C, where it combines with the
oxide of carbon. These two gases thus combined can be ignited in the chamber C³,
and the current of the flames represented by the arrows F, after having heated the
melting furnace F, follows a channel E, E2, E4, which leads it into a compartment G
under the preparing and finishing furnace. In this compartment G the flames
divide into four branches and issue respectively by two sets of six flues H and H³ at
the right and two other sets H3 and H at the left, after having heated the lower
arches of this furnace at H, H². In rising into the middle compartment a
portion of these flames heats the vertical sides of the channels C and D through
which the oxide of carbon and the atmospheric air pass, and these become heated
therein and acquire a temperature of about 300°. Another portion of the flames
in rising to the middle compartment heats the vertical sides of the compart-
ments O, P, O, P¹, of the finishing furnace in which are two cementing troughs.
While in the middle compartment J the flames heat the top of the cementing
troughs O, P, O, P, and also the underside of retorts P, Q, P, Q, and a heater C, A,
hereinafter described; then they pass into an upper compartment Js by flues at the
right and left; they thus heat the top of the retorts P, Q, P, Q, and the sides of the
heater C, A, and then they escape by passages K, K, into a flue L, from which the
gases arising from the combustion are conducted into a suitable chimney.
The retorts P, Q, are intended to receive the first or raw materials (cast iron or
Bessemer metal) which it is wished to purify and deprive of injurious metalloids.
For this purpose I can either previously introduce into the retort a layer of car-
bonate of lime in lumps with 2 or 3 per cent. of small coal (houille menue) on
which layer the material to be operated upon is placed; or after having enclosed
the metal in the retort, I can pass into it a current of hydrogenated carbonic acid.
These retorts having been charged, closed by a luted cover and heated to a tem-
perature of 1020° to 1110°, the carbonate is transformed into lime and disengages
carbonic acid gas and hydrogen, which react on the metal; the sulphur, phosphorus,
or arsenic as well as the carbon in excess are absorbed by the carbonic acid and
pass into the compartment J³ by two orifices y, y, formed in the retorts for the
purpose, and thence into the chimney with the combustion gases. The hydrogen
on the contrary penetrates the pores of the metal and finds its way between the
molecules, thus causing a sort of intermolecular washing. It is well not to exceed
the temperature of 1110°, because beyond this the hydrogen unites with the metal-
loids and returns them in the pores of the metal
This first operation lasts about 8 hours.
The cast iron, having passed through the preparing furnace, is still hot, and is

page_text: furnace P, Q, 18 first placed in a cementing trough O, P', and covered with a cement
thus composed
==
Carbonized peat
Small caking or fat coal (houille grasse
menue)
-
Carbonate of lime
-
4 parts.
-
1 part.
-
2 per cent.
This metal submitted to cementation for 10 or 12 hours is withdrawn from the
the cast iron. The cast
stirring are run after 8 hours
troughs O, P¹, and ready to be put into the furnace with
iron and Bessemer metal mixed by the melting and
heating into ingot moulds on a revolving plate.
The steel thus obtained is as it were a raw material, which can be transformed into
any desired quality by means of the refining or finishing furnace.
This refining furnace is composed of two cementing troughs O, P, O, P¹, into
which there is placed, according to the quality of steel desired, dry peat with
washed and desulphurized coal, and 2 per cent. of carbonate of lime to produce
mild fibrous steel with ordinary grains; or carbonized peat with one part of small
coal (houille menue), and two per cent. of carbonate of lime to obtain a harder
fibrous steel with closer grains, or carbonized peat with 1, small coal (houille
menue), and 2 per cent. of carbonate of lime, to obtain very hard fibrous steel
with microscopic grains.
This cementing furnace with continuous flame presents no difficulty in charging
and discharging the troughs O, P¹, containing the metals to be cemented, being
movable and made to slide or roll.
The refining is effected as follows:-The heater C, A, is full of iron or copper
waste and cuttings, and is intended for the production of nitrogen. Atmospheric
air, slightly moist and a little compressed in a suitable holder, is injected into a
pipe M; this pipe passes through the flames of the furnace so that the air becomes
heated, and it afterwards enters the heater C, A, by small pipes x. The cuttings
and waste in the heater being heated to a dull red, oxidize in the passage of the
atmospheric air from the pipe M, this air passing through the whole layer and the
nitrogen set free rises to the upper part of the heater, from which it is conducted
by the pipe C, B, and the pipe R², arranged as hereinafter explained, into the
cementing trough O, P¹. Cocks on one of the pipes C, B, allow of nitrogen and
hydrogen being sent into the troughs O, P, at intervals.
Figure 5, Sheet 2, shows in detail the arrangement for allowing the troughs O, P¹,
to communicate with the pipe R². Opposite each cementing trough is a branch
pipe S at right angles to the pipe R³, and in communication therewith. This pipe S
rises vertically and stops at the base or bed of the cementing furnace, where a
small damper allows of closing the aperture during the manipulation of the trough
O, P. In each trough O, P¹, is fixed at the bottom a horizontal tube Ts formed
with small holes throughout its length. At one of its ends is a vertical pipe T
for putting it into communication with the pipe R³, by which the nitrogen is supplied.
In the vertical pipe T is fitted a movable pipe T slightly conical at its lower end,
and easily raised or lowered by means of a rod m and lever n. When it is required
to remove the trough O, P¹, from the furnace, the lever n is pressed down, the pipe T
rises, and the trough being thus clear of all obstruction, can be withdrawn. The
returning of the trough to position is effected in the same manner.
The arrangement of cementing furnace without a melting furnace represented in
Figures 1 to 4, Sheet 2, differs from that already described only in the absence of
the melting furnace, and the arrangement of the heating channels and of the fire
place required for direct heating by a suitable fuel; this heating may be effected
as before with oxide of carbon. The arrangement includes the cementing troughs
and heater previously described for supplying nitrogen, these being put into com-
munication by the same arrangement of pipes.

page_text: And having now described the nature of the said Invention and in what manner
the same is to be performed, I declare that I claim,―
First. The manufacture of steel, substantially in the manner and by the process
or processes herein before described.
Second: The improved furnaces or apparatus to be employed in the manufacture
of steel, constructed and working, substantially as hereinbefore described, and
represented in the annexed Drawings.
In witness whereof, I, the said John Clayton Mewburn, have hereunto set
my hand and seal, this Ninth day of July, One thousand eight hundred
and seventy nine.
J. C. MEWBURN. (L.S.)