IMPROVEMENTS IN THE MANUFACTURE OF IRON AND STEEL
Year: 1869

page_text: PROVISIONAL SPECIFICATION left by Thomas Schoenberger Blair at
the Office of the Commissioners of Patents, with his Petition, on
the 10th August 1869.
I, THOMAS SCHOENBERGER BLAIR, of Pittsburg, Pennyslvania, in the
5 United States of America, but now residing at the Tavistock Hotel,
Covent Garden, in the County of Middlesex, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF
IRON AND STEEL," to be as follows:-
My Invention has reference to a new process for producing wrought
iron by intimately mixing with molten cast iron solid oxidizing sub-
stances as described in the Specification to certain Letters Patent granted
to Charles Denton Abel, dated 23rd November 1868, No. 3565. It is well
known that a variety of results can be produced in the crucible in the
treatment of iron or steel with certain substances which either enter
into combination and form an alloy or act as detersives by combining
with and carrying off impurities which would otherwise remain to the
detriment of the product, but when these same substances have been
tried in any open treatment, as the blast furnace, puddling furnace, etc.,
the results have been of little or no value.

page_text: By the process described in the above-mentioned Specification a new
method of bringing detersive agents and useful alloys into use is rendered
available, and my present Invention consists in one part in the employ-
ment of and mode. of applying certain substances to be hereafter
described in the said process which act either as detersives or as useful
alloys. For such purposes I employ, firstly, manganese. In this case I
take any of the various oxides of that metal according to economic
advantage and reduce it to about the same degree of fineness to which
the iron or other oxide has been reduced that is to be employed in the
manufacture of the conglomerate or "pig bloom" by the aforesaid
process. It may be in the form of powder, but as it is important that it
should be well and evenly mixed through the ore it will be found
desirable to have the two materials of about an equal degree of fineness.
To determine the quantity of oxide of manganese that should be
employed it is best to commence with test mixtures, whereby to
establish rules for the use of any particular materials that are to be
operated with. There is such a wide variation in the composition and
character both of the manganese and iron materials that no other method
is safe. But it may be stated in general terms that a good test mixture
to commence experimenting with is such as will give about one per cent.
of metallic manganese to the weight of metallic iron in the "pig bloom."
This proportion can be varied according to the results. obtained. from the
tests. The mixing of the oxide of manganese and the iron ore can be
done by weighing or, measuring, off the desired proportion of each and
repeatedly turning them over, with a shovel. The mixture. is then to be
used precisely as if it were the ordinary, oxidizing. material employed for
making the pig bloom, and the latter. is to be treated: in the ordinary
way. It will be found that the iron produced is much stiffer and closer
grained than it would have been without the manganese, that it contains
less impurities, and that the cinder from it in the heating of the "pig
bloom" is a more valuable article for blast furnace use, producing better
iron. Iron thus produced having a hardness not due to, carbon, and being
thus capable of enduring the same heat as other iron, can be employed
advantageously in. the manufacture of rails, tyres, and other articles in
which it is desirable from motives of economy or safety to use.iron for
the body and steel or its equivalent for the wearing surface. All that.is
needed is to compose the pile with the desired quantity and position of
hard iron, and it can be welded up as is, done with any ordinary pile of
one sort of iron. It can also be substituted for low steels generally, for

page_text: "
such purposes as call for density, hardness, fine polish, and the like.
The iron so produced is also better adapted for use in the application of
"pig bloom" or "pig scrap
"iron to the manufacture of steel. I also
sometimes employ chromium in the place of manganese. The method
of applying this and the proportions employed are substantially the same
as above described with reference to manganese, and the result is a
hardening of the iron. As in the case of manganese any of the ores
may be used according to convenience of supply. Where iron is desired
to be "cold short" I employ phosphorus, using iron ores especially
rich in this substance, or phosphate of lime, or indeed any of the
great number of substances into which phosphorus largely enters and
which do not contain objectionable constituents. The treatment is
substantially as before described, except that in the heating of the "pig
bloom" or "pig scrap
care must be taken not to expose them to too great
an amount of heat. The reason is that the ordinary treatment of pig
bloom and pig scrap throughly performed takes out nearly or all the
phosphorus in iron. Hence in the present case if the heat be great
enough and sufficiently prolonged all the phosphorus would go into the
cinder, rendering it less valuable for blast furnace use, and the wrought
iron would be no better for the extra trouble of supplying the phos
phorizing substance. With this substance test mixtures should be
commenced with such proportions as will yield about ½ per cent. of
phosphorus to the weight of the iron. I employ, furthermore, alumina
as a detersive agent, the only care necessary being that it shall not
contain or carry with it a large proportion of silica. The latter does not
injure the quality of the iron (as it is nearly all removed in the ordinary
course of the process), but it carries off a portion of the iron into the
cinder, and besides this renders the cinder less valuable from its silicious
character. In this case I mix ordinary clay with the oxide to the extent
of about 3 per cent. to the weight of iron in the pig bloom. Fluorino
may be used by taking fluor spar and reducing it to the required fineness.
As in the other cases the proportion must be determined by the character
of the materials employed, ore, pig iron, etc., it should be employed freely,
commencing with about 2 per cent. to the weight of metal. Lime in
the shape of a carbonate will be found useful in counteracting a cold
short tendency, but must be carefully avoided where red shortness is
already troublesome. I also make use of chlorine, taking about 1
per cent. of common salt and mixing it in its ordinary condition with the

page_text: ore. Before mixing the salt should be heated sufficiently to dry it
well, and after mixing the mass should be kept hot enough to prevent
its becoming-sticky by the absorption of the moisture of the air. Fur-
thermore, I employ zinc as a valuable detersive agent for red short
materials, which can be used as it occurs in the mineral "franklinite,"
which contains it as an oxide combined with iron and manganese. Any
quantity of it may be used, as this mineral worked alone produces iron of
good quality. I also produce a useful alloy by using the mineral
"wolfram," which contains tungsten, and which when incorporated in the
pig bloom will give up a part of the metal, which combining with
the iron will increase its hardness and also make it more desirable for
use in steel manufacture. The admixture of the mineral should be such as-
would give about per cent. of tungsten to the weight of iron. In the.
same way I produce an alloy of titanium and iron, the former giving
additional body" to the latter. For this purpose I use the mineral
"ilmenite" or other titaniferous ores of iron, adding such a quantity as
will give about per cent, of titanium to the weight of iron.
66
In the foregoing I have spoken only of using each chemical agent
separately, but this has only been done to indicate the method of
applying each. It is evident that combinations can be used whereby to
obtain results more desirable than any one of those ingredients alone
will afford; for example, the mixture sometimes introduced into the
puddling furnace known as "Schafhautl's powder" consists of 3 parts,
by weight, of oxide of manganese, 5 of salt, and 15 of clay, and of this
mixture 3 per cent. of the weight of cast iron is used in puddling. By
introducing the same compound in the same proportions to the iron into
the oxide prepared for making the "pig bloom" or "pig scrap" the
chemical effects so feebly or doubtfully realized in puddling are obtained
freely and regularly. Although I have in the foregoing indicated
certain proportions for the admixture of the alloys or detersive agents,
yet I in no way limit myself to such proportions, as they may be
variously modified according to circumstances. Several masses of pig
bloom, either with or without the admixture of detergents or alloys as
above described, may be combined together by welding to form one
homogeneous mass of a size proportionate to that of the article to be
produced, for which purposes the "pig blooms" are all first heated to a
high degree in order to perfect their conversion into wrought iron and to

page_text: eliminate impurities as described in the before-mentioned Specification,
and they are then welded together under a steam hammer or otherwise,
after which the combined mass before being allowed to cool down may
be reheated in the finishing mill and be at one passed through the rolling
mill or otherwise treated to produce the article required.