IMPROVEMENTS IN THE MANUFACTURE OF STEEL AND SOFT IRON FROM CAST IRON
Year: 1867

page_text: LETTERS PATENT to James Hargreaves, of Appleton-within-Widnes, in
the County of Lancaster, Analytical Chemist, and Thomas Robinson,
of Widnes, in the same County, Ironfounder, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF STEEL AND SOFT IRON FROM CAST
IRON."
Sealed the 19th November 1867, and dated the 22nd May 1867.
PROVISIONAL SPECIFICATION left by the said James Hargreaves and
Thomas Robinson at the Office of the Commissioners of Patents, with
their Petition, on the 22nd May 1867.
We, JAMES HARGREAVES, of Appleton-within-Widnes, in the County of
Lancaster, Analytical Chemist, and THOMAS ROBINSON, of Widnes, in the
same County, Ironfounder, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF STEEL AND SOFT IRON
FROM CAST IRON," to be as follows:-
Our Invention consists in the employment or use of any of the salts yeilding
oxygen on the application of heat, such as the nitrates, chlorates, chromates,
manganates, and stannates, mixed or in combination with any of the oxides of
iron or manganese, or any other suitable powdery or granular substance, as
agents to act on fused or molten cast iron and burn out therefrom at any
desired speed the excess of carbon in the said cast iron, and thereby convert
it at one operation into steel or soft iron. The said salts mixed or in
combination as aforesaid are placed in contact with or amongst the molten

page_text: cast iron. The proportion of the oxygen yielding salts to the oxide of iron,
or manganese, or other powdery or granular substance, determines the rate
at which oxygen will be eliminated and the proportion of the mixture or so-
called converting agents brought into contact or mixed with the cast iron will
determine whether the product is steel or soft iron; either can be produced at
pleasure.
Of the many modes of carrying our Invention into operation we prefer to
adopt the following:-(a) we build or fit into the bottom of the ladle or
converting vessel dried bricks or blocks made of the converting agents; or
(6) we pack or "tamp" the said converting agents preferably in a moistened
state into the bottom of the converting vessel, utilizing the heat from the
former charge to dry the said converting agents, the liquid metal is then
allowed to flow into the said converting vessel; the gas given off from the
converting agents rises to the surface of the mass of iron and completes the
conversion as above mentioned.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Hargreaves and Thomas Robinson in the Great Seal
Patent Office on the 22nd November 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, JAMES
HARGREAVES, of Appleton-within-Widnes, in the County of Lancaster,
Analytical Chemist, and THOMAS ROBINSON, of Widnes, in the same County,
Ironfounder, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of May, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto. us, the
said James Hargreaves and Thomas Robinson, Her special license that we, the
said James Hargreaves and Thomas Robinson, our executors, administrators,
and assigns, or such others as we, the said James Hargreaves and Thomas
Robinson, our executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANU-
FACTURE OF STEEL AND SOFT IRON FROM CAST IRON," upon the condition (amongst
others) that we, the said James Hargreaves and Thomas Robinson, our

page_text: executors or administrators, by an instrument in writing under our, or their,
or one of our or their hands and seals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the same
was to be performed, and cause the same to be filed in the Great Seal
Patent Office within six calendar months next and immediately after the date
of the said Letters Patent.
NOW KNOW YE, that we, the said James Hargreaves and Thomas
Robinson, do hereby declare the nature of our said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement and accompanying Sheet of
Drawings (that is to say):-
Our Invention consists in the employment or use of any of the salts which
yield oxygen on the application of heat, such as the nitrates, chlorates,
chromates, manganates, and stannates, mixed or in combination with
any of
the oxides of iron or manganese, or any other suitable powdery or granular
substance, as agents to act on fused or molten cast iron to burn out there-
from at any desired speed the excess of carbon in and at the same time to
remove other impurities from the said cast iron, and thereby convert it at
one operation into steel or soft iron. The said salts called by us oxydising
salts mixed or in combination as aforesaid, are placed in contact with or
amongst the fused or molten cast iron. The proportion of the said salts to
the oxide of iron or manganese or other powdery or granular substance
determines the rate at which oxygen will be eliminated, and the proportion of
the mixture or so-called converting agents brought into contact or mixed
with the cast iron will determine whether the product is steel or soft iron;
either can be produced.
The object which we have in view in employing or using the converting
agents, mixed as aforesaid, is to retard, regulate, and moderate the otherwise
rapid action of the oxydising salts. The oxydising salt at present most
suitable is nitrate of soda in consequence of its lower cost and the high
proportion of oxygen which it yields, as well as from the fact that the soda
contained in it acts effectually in removing silicium, sulphur, and phosphorous.
We mix the several substances which form the converting agents together
either in a dry, moist, or plastic condition.
It will be obvious that as the proportions of carbon, silicium, sulphur, and
phosphorous contained in cast iron vary considerably, and that as steel
and soft iron are required with very different proportions of carbon for
different purposes (in all cases the entire absence of siliciuin, sulphur, and
phosphorous is desirable) it would be tedious to set forth at length all and

page_text: every the proportions of the converting agents which can or would be used in
practice; we therefore propose first to mention the principle upon which our
Invention is founded, and afterwards to give such illustrations as will enable
others to carry our Invention into operation.
The proportions of oxygen capable of being liberated or evolved from the
aforesa. xydising salts and oxides of iron and manganese are well known to
chemists; the quantity of oxygen capable of being liberated from any given
quantity of these substances mixed with clays, ochres, or other substances can
therefore be ascertained with ease. The removal of carbon from molten cast
iron by means of our Invention is effected by converting the carbou into carbonic
oxide or carbonic acid. When carbonic oxide is formed every eight parts of
oxygen remove six parts of carbon, and when carbonic acid is formed every
Now nitrate of soda in
eight parts of oxygen remove three parts of carbon.
contact with molten cast iron will yield 47 per cent., sesquioxide of iron,
30 per cent., and binoxide of manganese about 36.25 per cent. by weight of
oxygen. With the foregoing information the proportions of the materials
required to form the converting agents, and the quantity of the said converting
agents necessary to remove any desired amount of carbon to produce any
desired quality of steel or iron can easily be ascertained. In all cases the soda
contained in the nitrate is in excess of the quantity required to combine with
or extract the silicium, sulphur, and phosphorous contained in cast iron
if the said cast iron is of ordinary quality.
We will now proceed to describe some of the methods by which we carry
our Invention into operation when a separate converting vessel is used,
first describing a form or construction of converter which we have found
to answer well; this is shewn on the accompanying Sheet of Drawings
by Figs. 1, 2, and 3, which are respectively views in side elevation, horizontal
section, and vertical section.
a are semicircular pieces of metal bolted together; b, fire-clay backing, aud
c fire-brick lining; d is the discharging way closed by fire-clay e, door f, bar
and wedges g in the same manner as a foundry cupola; h, the tap hole, and a
the runner.
The bottom slopes downwards towards the door so that the
whole of the charge run or poured in at the top may be caused to flow out.
To make steel suitable for cutting tools we take for every hundredweight
of white cast iron the following mixture:-Nine pounds of nitrate of soda and
five pounds of binoxide of manganese, and mix them intimately, and whilst they
are in a moist condition we place them in the converting vessel, preferably
tamping, them down tightly into the bottom thereof; the nitrate of soda o
commerce is generally sufficiently moist for the purpose without any addition

page_text: of water. If the converting vessel has been used just before the converting
agents are placed or tamped therein the heat of its sides will usually be
sufficient to dry the mixture into a solid mass; if the heat is not sufficient we
place a small fire-grate containing fire just over the converting agents; if the
converting vessel has not been used immediately before filling the converting
agents thereinto we heat it by a fire, preferably placed inside, or we conduct
carbonic oxide from a cupola or other blast furnace by suitable pipes into the
converter and burn it so as to dry the mixture, or we use other combustible gas;
the fused iron is then allowed to run or is poured into the converting vessel
over the dried mass of the converting agents, whereupon decomposition takes
place, the oxygen and other products of such decomposition rising through the
mass of molten metal and removing the excess of carbon as well as the silicium,
sulphur, and phosphorous. The excess of carbon is removed by combining with
oxygen and forming carbonic oxide, and carbonic acid, and the other impurities,
together with the soda contained in the nitrate, when nitrate of soda is used,
rise to the surface of the mass in the form of a slag. When the converting
agents have been decomposed, and no further gas is evolved, the converting
vessel is tapped and the steel allowed to run out into suitable moulds.
other times we make steel suitable for cutting tools by using the same or like
proportions of converting agents to those above mentioned, first making the
said converting agents into bricks or blocks and packing them tightly into
the bottom of the converting vessel. When we use a separate converting
vessel we find in practice that the greater the depth of metal through which
the products of the decomposition of the converting agents have to ascend the
better are the results, inasmuch as the said products have more time to burn
out the carbon and absorb the impurities which it is desireable to remove from
the iron; we therefore prefer that the converting vessel should be narrow
or small in proportion to its depth.
At
To make soft or malleable iron we take for every hundredweight of white
cast iron the following mixture: -Twelve pounds of nitrate of soda and
eighteen pounds of sesquioxide of iron and mix them; we then tamp them
into the bottom of the converting vessel, and in other respects proceed as
described above in making steel for cutting tools.
We will now proceed to set forth how we carry our Invention into effect in
the ordinary puddling furnace in the course of the ordinary process of pro-
ducing malleable iron. We grind hematite ore and mix it into a plastic
condition, and to every three parts of the said hematite we add one part of
nitrate of soda, and make the mixture into balls or blocks. While the said
balls or blocks are soft we affix them on iron rods, such as on the ends of

page_text: rough puddled billets, and then dry them thoroughly; when dry they are hard
and firm and ready for use. As soon as the cast iron is melted in the
puddling furnace we press the said balls or blocks fixed on the iron rods down
to the bottom of the metal, whereupon the gases and other products evolved
cause violent agitation and effect the removal of the excess of carbon and
other impurities, thereby reducing the time required to bring the iron to
nature, producing a better quality and a larger quantity as the converting
agents supply iron. To the charge of an ordinary puddling furnace containing
about 480 pounds we add or apply 32 pounds of the mixture of hematite and
nitrate of soda above mentioned.
Although we have described herein-before the processes which we follow in
making steel and soft iron, as these denote the conditions in which iron is
usually required in commerce, it will be obvious that our Invention is equally
applicable to improving the quality of iron in hot blast and cupola furnaces.
When treating iron in the said hot blast and cupola furnaces we construct
them with a door or opening in their sides just above the level of the liquid
metal, and there-through by rods or otherwise press the balls or blocks of
converting agents; the mixture suitable for the puddling furnace described
above answers well down to the bottom of the furnace. To make a refined
iron in the finery furnace we use a small quantity of the converting agents
which we force to the bottom of the molten metal, as in making malleable or
soft iron in the puddling furnace.
And now having described the nature of our said Invention, and particu-
larized the same by various modifications, so that iron workers will be enabled
to carry our Invention into effect, we would have it understood that we do not
confine ourselves to the use of particular proportions of the materials
mentioned as composing the converting agents, nor to the use of the mixtures
or proportions named herein, or of any particular quantity of the converting
agents, as these can be variously used according to the character or quality of
the iron operated on so as to produce the desired quality; for instance, when
we wish to obtain more rapid removal of carbon and other impurities we use
a larger proportion of the converting agents, and when we wish to obtain a
more tardy action we use a larger proportion of oxide of iron, oxide of
manganese, or other suitable powdery or granular substance. We would
also have it understood that although we prefer the oxides of iron and
manganese, as these are the substances most suitable to retard, moderate, and
regulate the decomposition of the oxydising salts, for in doing so they not only
yield oxygen, but increase the quantity of steel and iron, still titaniferous sand,
umbers, and ochres can be used, so also can both common and fire-clays,

page_text: ground slag, and other substances. We would further have it understood
that although we prefer to use the said converting agents stamped into a
cohesive mass or made into bricks or blocks we do not confine ourselves.
thereto, as they can be used in a loose state; and we desire here to point out
that the oxide of iron which we prefer to use is the purest hematite
practically obtainable, and the oxide of manganese which we prefer to use is
the purest native binoxide practically obtainable; what we claim is,-
First, the use or employment of oxydising salts mixed or in combination
with any suitable granular or powdery substance to form converting agents
to operate or act in the manufacture of steel and iron, substantially as herein
described.
Second, the use or employment of the converting agents herein described
when they are made into solid bricks or blocks, or tamped or packed into a
cohesive mass or into cohesive masses, substantially as herein described for
the purpose set forth.
Third, the use or employment of the converting agents herein described
when they are sunk into and kept amongst the fused or molten iron,
substantially in the manner and for the purpose herein set forth.
In witness whereof, I, the said James Hargreaves, have hereunto set
my hand and seal, this Nineteenth day of November, in the year of
our Lord One thousand eight hundred and sixty-seven.
In the presence of
JOHN T. KING,
Witness.
JAMES HARGREAVES. (L.s.)