IMPROVE- MENTS IN THE MANUFACTURE OF STEEL
Year: 1881

page_text: LETTERS PATENT to John Imray, of No. 28, Southampton Buildings,
Chancery Lane, in the County of Middlesex, for an Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF STEEL." A communication from abroad
by Pierre Einile Martin, of Paris, in the Republic of France.
PROVISIONAL SPECIFICATION left by the said John Imray at the Office
of the Commissioners of Patents on the 20th May 1881.
JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the County
of Middlesex. "IMPROVEMENTS IN THE MANUFACTURE OF STEEL." [A communi-
cation from abroad by Pierre Emile Martin, of Paris, in the Republic of
France.]
.
This Invention relates to the manufacture of steel by the Siemens-Martin process
in such a manner as to obtain products novel in their composition and properties,
and especially suited by their strength and temper qualities for the best and finest
tools. The improvements for this purpose depend chiefly on a preliminary pre-
paration of ores, of metals, and metalloids, besides those of iron, manganese, or
selicon, that is to say, of tungsten or wolfram, chromium, titanium, cobalt, nickel,
aluminium, magnesium, sodium, potassium, intended to dose the metal bath in the
furnace. This preparation consists in a complete reduction and a carbonaceous,
nitrogenous, or hydrogenous cementation of these ores by their prolonged contact
in closed retorts with reducing agents such as carbon, ammoniacal and nitrogenous
salts, hydrocarbons, and the like. The materials thus reduced to a peculiar spongy
condition being supplied to the steel bath give the steel novel composition and
qualities of a highly advantageous character. The complete steel process consists
of three operations.
1. The reduction and cementation of the ores bringing the products to the spongy
condition mentioned.

page_text: 2. The production of iron alloys of these products by melting them with iron
which may have been dosed with manganese or the like.
3. The application of these alloys to the metal bath in the Siemens-Martin furnace
so as to produce the improved qualities of steel.
:.
Each of these operations is conducted as follows:-
1. The first operation for reduction and cementation on the large scale is effected
by subjecting a mixture of the ores or metalloids with carbon and substances
containing cyanogen or hydrogen, cyanides, ammoniacal salts, carbonates, tartrates,
nitrates, hydrochlorates, hydro-carbons, to a long continued bright red heat in
retorts which may be horizontal, vertical, or rotative. The reduction may be
aided by passing reducing gas through the retort, thus obtaining a maximum of
cementation with carbon, nitrogen, or hydrogen. The action is regulated so as not
to fuse the materials, but by causing them to undergo reciprocal gaseous imbibition
to bring them to a spongy condition, which is readily recognised by its hygrometric
properties. The reducing apparatus preferred consists of a series of tubes heated
either by a regenerative furnace flame or by the waste gases of smelting furnaces,
or by the combustion of fuel of inferior quality. These tubes are somewhat taper,
being smaller at their tops where they are fed and larger at their bottoms, which
are closed by valves or doors until the operation is completed. The reduction and
cementation may however be effected in cupolas as they are employed for the
ferro-manganese and ferro-silicon applied in the production of mild steels. The
ores and reducing agents are mingled in small fragments or powder, or in bricks or
lumps made up with powdered charcoal, about 10 per cent. of lime, cyanide of
potassium, and sal-ammoniac.
On the small scale crucibles may be used for the reduction and cementation.
The ores and metalloids are bruised fine and intimately mixed with powdered
charcoal, preferably of soft quality with sawdust, dried straw or leaves, plants
containing potassa or nitrogenous substances, or with peat in pasty or pulverised
condition, with or without addition of a hydrocarbon. To these substances is
added a little cyanide of potassium with sal-ammoniac or nitrate of potassa,
nitrated carbon, or tartrate or carbonate of potassa or soda. The mixture is kept
heated to bright red during one to four days without fusion.
2. The second operation for producing the iron alloys is effected by melting the
spongy products obtained as above described in a cupola or smelting furnace, in which
they are introduced either by themselves or in alternate layers with iron ore, which
may be more or less mixed with iron turnings. Thus alloys may be obtained of
any desired proportions, as in the case of ferromanganese, which may contain as
much as 85 per cent. of manganese, and the alloys so produced may be termed
ferro-carbibes of tungsten, chromium, potassium, &c., as the case may be.
When the reduction and cementation is effected in a crucible the sponge need
not be withdrawn, therefrom, but may be fused in it with the addition of iron or
ferro-manganese. The following is an example of proportions that may be
employed-22 kilogrammes of tungsten ore or 14 kilogrammes of chromium ore
containing 45 per cent. of metal with equal bulk of charcoal, and 60 grammes of
prussiate of potassa or salammoniac.
3. The third operation for applying the ferro carbide alloys to the metal is
effected by introducing them in the required proportions into the bath of metal in
the Siemens Martin furnace. The iron is melted at two heats. The first melting
should be with charcoal and hydrogenous or other known materials tending to
assist the conversion into steel. Sometimes the sponge may be introduced directly
into the bath with previous alloying. The introduction of the sponge or alloy
causes development of great heat, so that the air supply must be reduced to save
the furnace from destruction. The beat evolved causes elimination of most of the
impurities, such as sulphur or phosphorus, by volatilising them, the substances
which remain in the furnace being only those which can resist this elevated tem-
perature, and which constitute the improved qualities of steel suitable for different

page_text: The dose of carbide could be increased, especially if hardness only is required.
The analyses of the two kinds of steel produced as above are:-
Graphite
Carbon in combination
No. 1. Chisel steel.
slight trace
0.835
0.289
0.085
0.063
0.010
No. 2. File steel.
0.134
1.627
}}
1.761
0:376
0.074
0.082
Silicon
Sulphur
Phosphorus
Tungsten
0.496
The large proportion of carbon, 1761, in No. 2, shews that a very considerable
quantity can be introduced in order to produce very hard steel besides the alloyed
metals or metalloids, thus neutralising the bad effects of impurities, such as phos-
phorus, sulphur, and silicon. The steel produced as described seems to differ from
ordinary cast steel only in the special character of the aggregation of the molecules
which gives the metal great hardness and tenacity, as shewn by experiments, from
which it appears that the steel untempered having an average tensile strength of
78 kilogrammes per millimetre of section, extended from 14 to 15 per cent., and
that the tempered steel having an average tensile strength of 114 extended about
$ per cent.
In a manner similar to that above described other metals or metalloids may be
alloyed with iron, such as aluminium, nickel, sodium, potassium, chromium,
titanium, cobalt, and especially manganese or silicon, producing new qualities of
steel. And such alloys, if they cannot be run as steel direct from the smelting
furnace, may be run therefrom in such form that they can be employed in the
Siemens Martin or other furnace, or in the Bessemer converter in the production
of steel,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Imray in the Great Seal Patent Office on the 18th November
1881.
JOHN IMRAY, of No. 28, Southampton Buildings, Chancery Lane, in the County
of Middlesex. "IMPROVEMENTS IN THE MANUFACTURE OF STEEL." A communi-
cation from abroad by Pierre Emile Martin, of Paris, in the Republic of
France.
This Invention relates to the manufacture of steel by the Siemens-Martin
process, in such a manner as to obtain products novel in their composition and
properties, and especially suited by their strength and temper-qualities for the best
and finest tools. The improvements for this purpose depend chiefly on a preliminary
preparation of ores of metals and metalloids, besides those of iron, manganese, or
silicon, that is to say, of tungsten or wolfram, chromium, titanium, cobalt, nickel,
aluminium, magnesium, sodium, potassium, intended to dose the metal bath in the
furnace. This preparation consists in a complete reduction and a carbonaceous,
nitrogenous, or hydrogenous cementation of these ores by their prolonged contact
in closed retorts with reducing agents such as carbon, ammoniacal and nitrogenous
salts, hydrocarbons, and the like. The materials thus reduced to a peculiar spongy
condition being supplied to the steel bath, give the steel novel composition and
qualities of a highly advantageous character. The complete steel process consists
of three operations.
1. The reduction and cementation of the ores bringing the products to the
spongy condition mentioned.
2. The production of iron alloys of these products by melting them with iron
which may have been dosed with manganese or the like.
3. The application of these alloys to the metal bath in the Siemens-Martin
furnace so as to produce the improved qualities of steel.
Each of these operations is conducted as follows:-
1. The first operation for reduction and cementation on the large scale is effected
by subjecting a mixture of the orcs or metalloids with carbon and substances
containing cyanogen or hydrogen, cyanides, ammoniacal salts, carbonates, tartrates,
nitrates, hydrochlorates, hydrocarbons, to a long continued bright red heat in
retorts which may be horizontal, vertical, or rotative. The reduction may be aided
by passing reducing gas through the retort, thus obtaining a maximum of cementa-
tion with carbon, nitrogen, or hydrogen. The action is regulated so as not to fuse
the materials, but by causing them to undergo reciprocal gaseous imbibition to
bring them to a spongy condition, which is readily recognised by its hygrometric
properties. The reducing apparatus preferred consists of a series of tubes heated
either by a regenerative furnace flame, or by the waste gases of smelting furnaces,
or by the combustion of fuel of inferior quality. These tubes are somewhat taper,
being smaller at their tops where they are fed, and larger at their bottoms which
are closed by valves or doors until the operation is completed. The reduction and
cementation may however be effected in cupolas, as they are employed for the
ferro-manganese and ferro-silicon applied in the production of mild steels.
ores and reducing agents are mingled in small fragments or powder, or in bricks or
lumps made up with powdered charcoal, about 10 per cent. of lime, cyanide of
potassium, and sal-ammoniac.
The
On the small scale crucibles may be used for the reduction and cementation.
The ores and metalloids are bruised fine and intimately mixed with powdered
charcoal, preferably of soft quality, with sawdust, dried straw or leaves, plants
containing potassa or nitrogenous substances, or with peat in pasty or pulverised
condition, with or without addition of a hydrocarbon. To these substances is

page_text: added a little cyanide of potassium with sal-ammoniac or nitrate of potassa,
nitrated carbon, or tartrate or carbonate of potassa or soda.
The mixture is kept
heated to bright red during one to four days without fusion.
2. The second operation for producing the iron alloys is effected by melting the
spongy products obtained, as above described, in a cupola or smelting furnace, in
which they are introduced either by themselves or in alternate layers with iron
ore, which may be more or less mixed with iron turnings. Thus alloys may be
obtained of any desired proportions, as in the case of ferro-manganese, which may
contain as much as 85 per cent. of manganese, and the alloys so produced may be
termed ferro-carbides of tungsten, chromium, potassium, &c. as the case may be.
When the reduction and cementation is effected in a crucible the sponge need
not be withdrawn therefrom, but may be fused in it with the addition of iron or
ferro-manganese. The following is an example of proportions that may be
employed-22 kilogrammes of tungsten ore, or 14 kilogrammes of chromium ore
containing 45 per cent. of metal with equal bulk of charcoal, and 60 grammes
of prussiate of potassa or sal-ammoniac.
3. The third operation for applying the ferro-carbide alloys to the metal is
effected by introducing them in the required proportions into the bath of metal in
the Siemens-Martin furnace. The iron is melted at two heats. The first melting
should be with charcoal and hydrogenous or other known materials tending to
assist the conversion into steel. Sometimes the sponge may be introduced directly
into the bath without previous alloying. The introduction of the sponge or alloy
causes developinent of great heat, so that the air supply must be reduced to save
the furnace from destruction. The heat evolved causes elimination of most of the
impurities such as sulphur or phosphorus by volatilising them, the substances
which remain in the furnace being only those which can resist this elevated
temperature, and which constitute the improved qualities of steel suitable for
different uses according to the proportions of the ingredients, as may be understood
from the following examples:-
No. 1. Steel for chisels, gravers, and the like.
run out at 5 p.m.
Pig iron
Furnace charged at 6 a.m.;
600

page_text: to
The large proportion of carbon, 1761 in No. 2, shews that a very considerable
quantity can be introduced in order to produce very hard steel besides the alloyed
metals or metalloids, thus neutralising the bad effects of impurities such as
phosphorus, sulphur, and silicon. The steel produced as described seems
differ from ordinary cast steel ouly in the special character of the aggregation
of the molecules which gives the metal great hardness and tenacity, as shown by
experiments, from which it appears that the steel untempered having an average
tensile strength of 78 kilogrammes per inillimetre of section extended from 14 to
15 per cent., and that the tempered steel having an average tensile strength of 114
extended about 8 per cent.
In a manner similar to that above described other metals or metalloids may be
alloyed with iron, such as aluminium, nickel, sodium, potassium, chromium,
titanium, cobalt, and especially manganese or silicon, producing new qualities
of steel. And such alloys, if they cannot be run as steel direct from the smelting
furnace, may be run therefrom in such form that they can be employed in the
Siemens-Martin or other furnace, or in the Bessemer converter in the production
of steel.
Having thus described the nature of this Invention, and in what manner the
same is to be performed, as communicated to me by my foreign correspondent, I
claim,―
First. The production of a spongy material resulting from reduction and cementa-
tion of metallic ores or metalloids effected by subjecting them to long continued
heat in admixture with reducing and cementing agents, substantially as herein
described.
Second. The production of alloys by fusion of iron and iron ore along with
spongy products such as are referred to in the preceding claim.
Third. In the manufacture of steel the admixture of alloys such as are referred
to in the preceding claim with the fused metal, substantially as and for the purposes
herein set forth.
In witness whereof, I, the said John Imray, have hereunto set my hand
and seal, this Eighteenth day of November, in the year of our Lord
One thousand eight hundred and eighty one.
JOHN IMRAY. (L.S.)