Improvements in the Manufacture of Cast Steel and Homogeneous Iron.
Year: 1895

page_text: Date of Application, 27th Nov., 1895
Complete Specification Left, 26th Aug., 1896-Accepted, 14th Nov., 1896
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Cast Steel and Homogeneous
Iron.
1, JOHN GJERS, of Ayresome Iron Works, Middlesborough-on-Tees, in, the
North Riding of the County of York, Engineer and Iron Master, do bereby
declare the nature of this invention to be as follows:-
My invention has reference to an improvement in the production of cast steel
and homogeneous iron from crude pig iron, without balling and shingling, rolling
into bars, cutting up and remelting as also without having (as proposed in the
Specification of my former Patent No. 3440 of 1867) to tap or remove the crude
steel metal from the puddling or equivalent furnace at or about the last stage
of fluidity and transfer it to and treat it in another furnace capable of giving and
maintaining the greater beat necessary to convert the metal into fluid steel or
homogeneous iron of the carburisation required.
Now according to my present invention crude pig iron is converted into cast steel
or homogeneous iron by treatment in a single furnace adapted to perform the
whole of the work namely that of a puddling furnace as well as that of a steel
melting furnace for which purpose the furnace which may (except as to its bottom)
be an ordinary open hearth steel melting furnace, bas its bottom on which the melted
metal is to rest made not of silicious material as used in the acid process or with
lime and magnesia as used in the basic process but of rich oxides of iron in a
finely divided state whereby the melted crude metal (which in this case may
advantageously be charged in a fluid state) is caused to boil and to come to nature
as it does in the puddling furnace, but being exposed to the greater heat of a steel
melting furnace is prevented from becoming semi-fluid or solid as it does in the
puddling furnace, and is caused to remain as fluid steel under a covering of rich iron
cinder or slag. Such iron cinder or slag may be tapped out of the furnace at the
proper time, that is, after the silicon, carbon and phosphorus have by the action of
the iron cinder been wholly or sufficiently removed from the crude iron, which will
bave become fluid steel ready to tap and cast into ingots after the preliminary
tempering with ferro-silicon or manganese as usual and well understood in the
ordinary practice of open hearth steel making.
Great care should be taken in making up the bottom of the furnace, that the
iron oxides, be they natural or artificial, shall be of the richest kind, that they
be pulverised and placed and beaten down solidly on a silicious foundation or on
a magnesia foundation. In the former case the sides and arch should be made
of silica bricks and in the latter of magnesia bricks; or in some cases fluid
rich iron cinder may be run over the silica or magnesia foundation to form the
Such cinder may be melted in a small adjoining furnace and run in
and allowed to set.
No lime is to be used, as in any case I depend upon the rich
iron cinder to absorb the silicon, the phosphorus and the sulphur, and to drive the
carbon out of the crude iron.
bottom.
In some cases I consider it advantageous to use rich ilmenite (titanic iron ore)
round the sides in conjunction with the exide of iron bottom, or even on the
bottom of the furnace, also, this substance being less fusible than ordinary iron
ore; but on the whole, pulverised rich magnetic iron ore containing say 72% of
iron will answer well and it is readily procurable. Crude pig iron comparatively-

page_text: free from phosphorus or such as contains a good deal of phosphorus may be worked
with equal advantage by my process of boiling on a rich iron cinder bottom, and a
purer result may be obtained than by either the acid or basic process at present
in use.
I call my process of steel making the oxide of iron process.
Crude pig iron may be charged cold into the melting furnace on the oxide of iron
bottom, the same as in the usual practice, but the oxide of iron bottom is well
adapted to such crude iron being charged in the fluid state, direct from the blast
furnace or cupola or accumulator as it promotes the boiling of the iron, which can
further be assisted at the early stage by a certain amount of rabbling; the same as
is done in the puddling furnace.
Iron ore or scrap may be added to the bath when found necessary, the same as in
the ordinary practice. Rich artificial iron scales or cinders may be classed
equivalent to rich natural iron ores.
By my present invention I am enabled to obviate the serious disadvantage which
prevented the adoption on a commercial scale of the process described and claimed
in the specification of my said former patent, namely, the difficulty of transferring
the contents of the puddling furnace at the proper time in a semi-fluid state from
that furnace to another.
Dated this 07th dow of Navaho 1005
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Cast Steel and Homogeneous
Iron.
I, JOHN GJERS, of Ayresome Iron Works, Middlesborough-on-Tees, in the
North Riding of the County of York, Engineer and Iron Master, do hereby declare
the nature of this invention and in what manner the same is to be performed to
be particularly described and ascertained in and by the following statement :-
In the ordinary puddling furnace (as is well known) crude iron is boiled on an
iron cinder bottom, but when it gets converted into the malleable state, the
temperature is no longer high enough to keep it fluid, consequently the metal sets
and comes out as puddle ball, that is, in the form of a sponge of malleable iron
full of iron cinder. In open hearth steel making, as usually practised, the crude
iron is (in the acid process) melted upon a bottom of silica, as pure as possible, and
when the metal is fluid, a quantity of iron ore is thrown in, which floats on the top
of the molten crude iron and materially assists in converting such crude iron, but
in consequence of the iron ore floating (as it does) on the top of the crude iron, it
takes a long time to effect the conversion. In the basic open hearth furnace the
bottom is formed of lime and magnesia, and, when the iron is melted, lime, and
occasionally, some oxide of iron is thrown in.
Now according to my present invention I combine, in the manner hereinafter
described, the conditions of the puddling furnace and the steel melting furnace
(that is to say) I melt the crude iron on an oxide of iron bottom but prevent the
resulting malleable or steely iron from passing into the solid form (as it does in the
puddling furnace) by maintaining a sufficiently high temperature to keep the metal
fluid so that it is ultimately tapped out as fluid steel or homogeneous iron (mild
steel).
In the Specification of my English Patent No. 3440 of 1867 I proposed to make
cast steel and homogeneous iron by treating crude pig iron or refined iron with

page_text: rich iron cinder in a puddling furnace (where, by the action of oxide of iron,
purification and conversion were effected) and then, at or before the stage called
top boil" (i.e. just before the metal began to thicken and to "come to nature," and
before it was fit for "balling up") transferring the metal into another furnace
capable of producing the high temperature required to melt cast steel or homo-
geneous iron. But I found that, in practice, when the metal had attained, in the
puddling furnace, a sufficiently pure state to be ready for transfer, it was not
sufficiently fluid to be readily transferred into the second furnace.
Now, in order to obviate the just mentioned disadvantage of the process
proposed by me in 1867, instead of using a puddling furnace with oxide of iron
lining and bottom, and transferring the metal from it into another furnace, I (having
found by experience that an extremely rich oxide of iron is highly refractory and
able per se to withstand even the highest temperature of the steel melting furnace).
according to my present invention, conduct the entire process in one furnace by
the use in such furnace of an extremely rich oxide of iron lining (in the form of a
rich iron ore) in conjunction with a temperature sufficiently high to melt cast steel
or homogeneous iron (mild steel). The furnace employed may be an ordinary open
hearth steel melting furnace (see the annexed drawing) but the bottom A on which
the melted metal is to rest and the lining round the sides B (instead of being made
of silicious material such as is used in the acid process, or with lime and magnesia,
as used in the basic process) are composed of rich oxide of iron, in a finely divided
state. Suitable material for my lining (especially round the sides B) is rich ilmenite
(titanic oxide of iron) this substance being less fusible than ordinary iron ore;
but, pulverised rich magnetic iron ore, containing 70% to 72% of iron, will answer
well, and it is readily procurable.
It is not necessary to use ilmenite or rich magnetic iron ore as any iron ore, if
it be rich enough, will answer the purpose, nor is it absolutely necessary (though
I prefer it) to use natural iron ores, as artificial iron ores such as purple ore
(commonly called Blue Billy), iron and steel scales from rolling mills used by them-
selves or mixed with natural iron ores will answer the purpose so that they be rich.
enough in iron, that is to say containing about 70% of iron.
Great care should be taken in making up the bottom A and sides B of the furnace,.
that the iron oxides, be they natural or artificial, shall be of the richest kind, and
that they be pulverised and placed and beaten down solidly on a silicious foundation,.
or on a magnesia foundation. In the former case, the sides and arch should be made
of silica bricks, and in the latter case of magnesia bricks. When I make or fettle
the bottom with granulated iron ore, I previously damp the ore with water containing
some alkaline or basic substance or solution, but I prefer doing it with ordinary
brine (solution of salt) so that under the influence of heat it may glaze together the.
small particles of iron ore so as to make the bottom as solid as possible.
I charge the furnace with crude pig iron and depend upon the oxide of iron
bottom to start the boil and to maintain it as soon as the pig iron is melted;
after it is melted I proceed in the ordinary way, (that is to say) I charge or may
not, more iron ore, or malleable iron or steel scrap onto the fluid iron as may be
desired and as is ordinarily done. As soon as the pig iron begins to melt, it is acted
upon by the oxide of iron bottom, which is gradually decomposed, oxygen combining
with the silicon, phosphorus, aud carbon, and (may be) any sulphur and manganese
and leaving with the metallic iron that is produced out of the ore by deoxidation
more or less pure iron or steel, the whole of the iron or steel being maintained in a
melted state by the heat of the furnace and ultimately, after having been treated
and tempered in the usual way by ferromanganese or ferro-silicon, is tapped and
run into ingots.
I
Before completing the process by adding the ferro-manganese or ferro-silicon,
may not, run the bulk of the fluid cinder floating ou the top of the fluid
iron or steel from the furnace.
may, or
Crude pig iron, whether comparatively free from phosphorus, or containing a
good deal of phosphorus, may with equal advantage be worked by my process of

page_text: boiling on a rich iron cinder (oxide of iron) bottom, and a purer result can be
obtained than by the acid or basic processes at present in use.
It will be noted that it is not necessary, indeed it is harmful to add any lime or
magnesia to the charge in this process of boiling on an oxide of iron bottom,
and it is not necessary that the oxide of iron should be absolutely free from
phosphorus, only that it be sufficiently rich and comparatively free from sulphur.
Although I have stated that the crude pig iron is charged cold on to the oxide
of iron bottom of the melting furnace, it may be charged in the fluid state,
direct from the blast furnace, or cupola, or accumulator, as the oxide of iron
lining promotes the boiling of the iron, which can further be assisted, at the
early stage, by a certain amount of "rabbling," as is ordinarily done in puddling
furnaces.
By my present invention I am enabled to obviate the serious disadvantage
which prevented the adoption on a commercial scale of the process described and
claimed in the specification of my said former patent, namely, the difficulty of
transferring the contents of the puddling furnace at the proper time in a semi-fluid
state from that furnace to another.
Although as above stated this oxide of iron process can be carried on to
advantage in the ordinary Siemens openhearth melting furnace, as shown, still
I prefer to carry it out in openhearth furnaces of my invention with surface
combustion of solid fuel by hot air (see the Specifications of my Patents No. 2720
of 1894 and No. 10,815 of 1895) whether such furnaces be single or of the duplex
kind formning the subject of my application for Patent No. 123 of 1896 and
I strongly recommend that the hot air be driven through the furnace as a mild air
blast instead of being drawn by suction from a chimney or any other means.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that I do not
claim broadly the treatment of crude pig iron on an oxide of iron bottom, nor do
I claim the melting of steel or homogeneous iron (mild steel) on the bed of an open-
hearth or like furnace having a sufficiently high temperature for the purpose, but
what I do claim is :-
The manufacture in the improved manner hereinabove described of cast steel or
homogeneous iron (mild steel) from crude pig iron or refined iron, the lining of the
furnace bed upon which the material is treated being made of a very rich oxide of
iron or rich ilmenite (titanic iron ore) or both to the action of which conjointly
with the action of a high temperature such as required to melt cast steel or homo-
geneous iron (mild steel), the material to be converted is subjected simultaneously
as and for the purpose specified.
Dated this Ofth das of Aus 1806