IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1879

page_text: LETTERS PATENT to Henri Guillaume Harmet, of Denain, in the Republic of
France, Son and Administrator of Jean Marie Harmet, late of 33, Rue de la
Charité, Lyons, Republic of France, Civil Engineer, who departed this life on
the 21st day of August 1879, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF IRON AND STEEL."
PROVISIONAL SPECIFICATION left by the said Jean Marie Harmet at the
Office of the Commissioners of Patents on the 14th February 1879.
JEAN MARIE HARMET, of 33, Rue de la Charité, Lyons, Republic of France, Civil
Engineer. IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL."
"
This Invention has for its object improvements in the manufacture of iron and
steel.
In refining cast iron in converters, such as are usually employed, the phosphorus
being protected by a slag in which silica predominates, entirely escapes oxidation
and remains in its entirety in the resulting steel.
The present Invention consists in a modification of the process of refining, and
has for its object the oxidation of the phosphorus just as completely as that of the
silicium, and consequently allows of the treatment of phosphatic irons.
Hitherto the process of refining has been performed at one operation and in a
single converter, and under the influence of a more or less silicious slag.
In my process, on the contrary, the refining is divided into two distinct operations
performed in two distinct converters, and under the influence of essentially different
slags.
The first operation which is performed in a converter lined in the ordinary
manner, that is to say, with refractory silicious matters, has for its object the
combustion of the silicium. There is equally a combustion of a certain variable
quantity of carbon, of manganese, and of iron, according to the time chosen to
terminate the operation.
During this first operation a silicious slag is formed.

page_text: The metallic bath which as is known has been raised to a very high temperature
by the rapid combustion of the silicium, is a phospho-carburet of iron, or approxi-
mately a phosphatic steel.
To perform the second operation the metallic bath is transferred into a second hot
converter with a refractory basic lining. In the transfer precautions are taken
necessary prevent the introduction with the metal of any of the silicious slag into
the second converter.
This second-operation has for its object the burning of the whole of the phosphorus
_and_bringing-the-carbon-to-suitable-proportions, according to the steel it is wished
_to_obtain.
-
-In-the-first-converter I-operate with the blast alone; in the second I concurrently
use alcaline, earthy, or metallic bases always in a manner such as to keep the slag
strongly basic in spite of the formation of phosphoric acid.
The combustion of the phosphorus largely suffices to keep the bath at the
necessary temperature, and when the operation is complete it is terminated in the
ordinary manner, with the exception of the differences caused by the presence of a
basic slag.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Guillaume Harmet, Son and Administrator of Jean Maric
Harmet, deceased, in the Great Seal Patent Office on the 29th December
1879.
HENRI GUILLAUME HARMET, of Denain, in the Republic of France, Son and
Administrator of Jean Marie Harmet, late of 33, Rue de la Charité, Lyons, Republic
of France, Civil Engineer, who departed this life on the Twenty-first day of August,
One thousand eight hundred and seventy nine. IMPROVEMENTS IN THE MANU-
FACTURE OF IRON AND STEEL."
$8
This Invention has for its object improvements in the manufacture of iron and
steel.
In refining cast iron in converters, such as are usually employed, the phosphorus
being protected by a slag in which silica predominates, entirely escapes oxidation
and remains in its entirety in the resulting steel.
The present Invention consists in a modification of the process of refining, and
has for its object the oxidation of the phosphorus just as completely as that of the
silicium, and consequently allows of the treatment of phosphatic irons.
Hitherto the process of refining has been performed at one operation and in a
single converter, and except in the process patented by Sidney Gilchrist Thomas,
under the influence of a more or less silicious slag.
In my process, on the contrary, the refining is divided into two distinct operations
performed in two distinct converters, and under the influence of essentially different
slags.
The first operation, which is performed in a converter which I prefer to be an
ordinary tipping or fixed Bessemer vessel lined in the ordinary manner, that is to
say, with refractory silicious matters, such as gannister or silica bricks, has for its
object the combustion of the whole or nearly the whole of the silicium. There is
equally a combustion of a certain variable quantity, sometimes all of the carbon, of
manganese, and of iron, according to the time chosen to terminate the first operation,
which may be continued till the drop of the flame, or stopped some minutes before
this point, according to the quantity of phosphorus to be removed. I prefer to stop
the operation about 90 seconds before the drop of the flame.
During this first operation a silicious slag is formed as is usual.
The refined metallic bath which as is known will be thus raised to a very high
temperature by the rapid combustion of the silicium, is a phospho-carburet of iron,
or approximately a phosphatic steel, or a bath of wrought iron, rich in phosphorus.
To perform the second operation the hot bath of phosphoric iron or metal is very
rapidly transferred by a ladle or runner into a second hot converter, which may be
either a Bessemer converter or any other kind of converting furnace, and must be
furnished with a basic lining, which I prefer to be of magnesian lime bricks.
In the transfer precautions are taken to prevent the introduction into the second
converting apparatus of any of the silicious slag. This may be either skimmed off
in the runner, or separated by tapping the metal from the bottom of the transfer
ladle.
This second operation has for its object the burning of the whole of the phosphorus
and bringing the carbon to suitable proportions according to the steel it is wished to
obtain. The second converting or dephosphorising vessel may be a Bessemer vessel
or any form of open hearth furnace, such as a Pernot, Siemens, or other furnace, with
or without blast. I generally prefer the Bessemer or the Pernot furnace or con-
verter. In the first converter I operate with the blast alone. In the second or
dephosphorising apparatus I use basic substances, namely, lime and oxide of iron,
amounting to about eight times the weight of the phosphorus in the metal to be
treated, so as to keep the slag strongly basic. Fluor spar, chloride of calcium, or
salt may be mixed with the other bases to promote fluidity. I do not however lay

page_text: claim to dephosphorising by basic substances. When blast is used in the dephos-
phorizing converter, a part of the lime may be injected in powder in the blast.
When blast is used in the second converter, I form by preference the basic slag with
lime only. When blast is not used I use a large proportion of oxide of iron. The
oxidation of the phosphorus assists in maintaining the temperature of the second
bath. When a sample taken from the bath shows by its good steely fracture and
grain that the phosphorus is entirely removed, I pour off the basic slag in great
-part and add-the-necessary-amount-of-spiegel.
I-do-not-claim
refining-in-a-silicious-Bessemer--or-other-converter-by-itself, nor
-dephosphorising-in-a-basic-converter-by itself.
But I claim the improved process for the manufacture of steel and (ingot) iron,
-consisting of the combination of a preliminary desiliconising in a silicious lined
vessel, with a subsequent treatment and dephosphorisation of the phosphoric metal
in a basic lined vessel or furnace, with basic additions, substantially as herein
described.
In witness whereof, I, the said Henri Guillaume Harmet, have hereunto set my
hand and seal, this Eighteenth day of December, in the year of our Lord One
thousand eight hundred and seventy nine.
HENRI HARMET. (L.S.)