IMPROVEMENTS IN THE PRODUCTION OR MANUFACTURE OF STEEL AND IRON OF A STEELY CHARACTER
Year: 1868

page_text: LETTERS PATENT to Charles Attwood, of Wolsingham, in the County
of Durham, Ironmaster, for the Invention of "IMPROVEMENTS IN THE
PRODUCTION OR MANUFACTURE OF STEEL AND IRON OF A STEELY CHARACTER."
Sealed the 8th May 1868, and dated the 10th March 1868.
PROVISIONAL SPECIFICATION left by the said Charles Attwood at
the Office of the Commissioners of Patents, with his Petition, on
the 10th March 1868.
I, CHARLES ATTWOOD, of Wolsingham, in the County of Durham,
Ironmaster, do hereby declare the nature of my said Invention for
"IMPROVEMENTS IN THE PRODUCTION OR MANUFACTURE OF STEEL AND IRON OF
A STEELY CHARACTER," to be as follows:-
My Invention of an improved method or methods of making cast
steel and of iron in the state of steel iron or of a kind of iron approximate
to steel, consists in taking crude iron in the melted state and bringing
it into a state of either entire or of partial decarbonization to whatever
degree may be for the special occasion desired by means of blowing
through it a blast of atmospheric air or otherwise applying oxygen

page_text: thereto beneath the surface, and in afterwards passing such decarbonized
or partially decarbonized iron whilst still in the liquid state and at
the highest degree of temperature that conveniently may be into the
highly heated hearth or chamber of an open reverberatory furnace,
which chamber may be heated either by the flame of coal or other
similar fuel consumed upon a furnace grate in the manner which is
usual in such furnaces as ironfounders' air furnaces, or else heated
partly by such flame and partly by the flame of gas or gases carried
into or mingled with the flame of such fuel according to any convenient
method, or else heated solely by the flame of gases according to any
known or convenient methods. In such open hearth furnaces the said
decarbonized or partially decarbonized iron is to be mixed in proportion
to its actual degree of decarbonization with such different quantities,
whether added at once or in successive portions of crude or non-malleable
or of malleable iron respectively, and preferably in a highly heated or in
a melted state as may be required in order to bring the whole by means
of the liquid interfusions and the due proportions of its parts into such a
condition of hard or of soft steel or of hard or soft steely or steel iron
respectively as it may be desired to produce.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles Attwood in the Great Seal Patent Office on
the 5th September 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
ATTWOOD, of Wolsingham, in the County of Durham, Ironmaster, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of March, in the year of
our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Charles Attwood, Her special license
that I, the said Charles Attwood, my executors, administrators, and
assigns, or such others as I, the said Charles Attwood, my exccutors,
administrators, or 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,

page_text: "
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
THE PRODUCTION OR MANUFACTURE OF STEEL AND IRON OF A STEELY CHARACTER,"
upon the condition (amongst others) that I, the said Charles Attwood,
my executors or administrators, by an instrument in writing under my
hand and seal, 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 calender months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said Charles Attwood, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
the following statement, that is to say :-
My Invention of an improved method or methods of making cast
steel and of making iron of a steely character, which I call steel iron
as being a kind of iron approximate to steel, consists as follows:-I take
as my material such metal, whether in the state of iron or in that of
steel whilst still in the melted state, as may have been previously
brought out of the state of non-malleable or crude cast iron into such
a degree of decarburisation as to have become malleable by the means of
blowing through it or into it whilst in a melted state a blast or current
of atmospheric air, according to the process well known to metallurgists
by the designation of "the Bessemer process," or which may have
been brought into such a condition by any other means of applying
either atmospheric air or other substances containing oxygen to such
crude metal in the melted state either beneath the surface or otherwise
as one of my materials, and I take crude, cast, or non-malleable iron
either in a melted or in a heated state or otherwise, if in any case more
convenient in either a heated or in a cold state as my other materia!,
which ingredients I mix together in the hollow or excavated hearth
or bottom of a suitable reverberating furnace in such manner or manners
as herein-after described, and in such proportions as under a very high
and sufficiently continued heat may bring the whole mass while in a
state of fusion to the proper chemical or metallurgical condition or
quality of such descriptions of hard or soft steel or of steel iron (or
steely iron) respectively as it may be intended to produce, after which
I tap the furnace and draw off the metal cither directly into ingots or

page_text: other moulds or indirectly by tapping it previously into ladles as may
be found in any case more convenient.
As regards the kind of reverberating furnace to be thus employed I
have found that though a furnace similar to the common ironfounders'
reverberating furnace heated by coals burning upon the usual kind of
grate is capable of giving sufficient heat to so liquify or hold in liqui-
faction the said mixture, yet inasmuch as the obtaining and maintaining
a higher and more uniform temperature, and by means of a flame more
free from ashes and from sulphur than from such furnaces and grates
can be obtained, and also inasmuch as no considerably greater quantity
of oxygen should pass into or through the melting chamber than may
be readily for the most part absorbed or consumed by the carbonaceous
or other gases of the furnace, I prefer the employment of a furnace
heated by the combustion of gases, such as carbonic oxide or carburutted
hydrogen or other hydro-carbonaceous matters according to any known
or suitable method of employing them in furnaces, and I have found
the sort of furnace well known and used for steel meltings called the
"Siemens' regenerating furnace," to be very suitable and effective for
my purpose, although the same result may also be obtained by other
furnaces and other modes of burning such or similar combustible gases
such as persons skilled in such operations may preferably construct and
employ. The furnace must have a tapping hole which may be similar
to such as is usually used in ordinary ironfounders' reverberatories, and
which may best be placed at or about the middle or deepest part of the
excavated sole or hearth thereof, and so that it may be stoppered up in
any manner usual or convenient in such furnaces. There must be also
openings at which to run in or charge the fluid or solid metals or
materials which may be employed, and for taking out such small
quantities for testing as may be desired, which openings should be so
constructed as to be well and speedily closed and luted up after using
them. The hollowed out or excavated hearth of the reverberating
chamber must be of such size and depth as the quantity of metal
intended to be cast from each separate melting may require and may
contain either small quantities of, say, three, four, or five hundredweight
of metal, or as much as three, four, or five tons or more according to the
size of the ingots or other castings required, the time required for
working off a charge of such large quantities being of course longer than
in the case of smaller, but for which smaller quantities from one to three

page_text: hours will generally be amply sufficient. The brick or stonework or
foundation of the hearth should be covered as usual in ironfounders'
reverberatories with silicious sand in a moderate degree ferruginous, or
better still with rather coarsely ground "ganister" well rammed down to
the considerable depth or thickness of somewhere about 18 inches, which
also may advantageously be itself covered to the thickness of from six
inches to a foot with an upper layer of the same sand or of ganister
which may preferably be more finely ground and mixed to the extent of
about one-eighth of its weight with a somewhat fusible sort of sand or
loam, such as is well known to and used by ironfounders' by the name
of "Woolwich loam." The inside walls and the arch or crown of the
furnace may advantageously be made of "ganister bricks," or of the
sort of bricks called "Dinas bricks."
The proportions in which the two kinds of metal are to be used must
vary according to the degree in which the malleable metal used as the
material may have been previously more or less completely decarburised
or brought into the state of hard or soft steel, or of hard or soft iron; but
by way of general rule I mention that in any case in which that
decarburization may exist to about the same degree to which it is
usually carried in well puddled bar iron a mixture of crude or cast iron
therewith in the proportions of about from eight to about fifteeen per
cent. of the total or mixed mass of metal will yield a more or less soft or
hard steel iron, whilst the mixture of such crude metal in the proportion
of from about fifteen to about forty per cent. of such total mass will
give either such a soft or such a hard steel as may be suitable for most
of the various purposes for which steel is generally employed.
As regards the mode of mixing my materials I prefer that the crude
or non-malleable metal which may be employed should be melted in
the reverberating furnace itself before the addition of the other material,
though otherwise it may where more convenient be conveyed into the
said furnace out of some other furnace or vessel whilst in a melted state,
and I recommend that in either case it be brought to a state of liqui-
faction before the addition of the decarburised material. And inasmuch
as it may sometimes be convenient for purposes of economy or otherwise
to add to these materials in the reverberating furnace a greater or less
proportion of steel, or of such steel scrap as it may be desired to work
up and bring into the state of cast steel ingots, such addition may be
made either by adding it to or liquifying it at first along with the crude

page_text: cast iron, or else by mixing it with the other materials, and it may either
be added in the cold or in the melted state to the metal in the furnaces.
"
It is usual in the practice of what is called "the Bessemer process
to first decarburise the iron and then to add to it while in the con-
verter, and still fluid, as much crude metal, also in the liquid state, as
is judged sufficient for converting it to steel; and in that state those
mixed materials in the state of steel may then be passed into my
furnace and brought by continued liquifaction either with or without
commixture with a further quantity of either crude metal or decar-
burised iron as may be necessary, to such a condition in respect of
quality or hardness as may be desired. But I consider it more
convenient not to previously make such mixture with crude metal in
such converter, but to pass the metal decarburised as nearly as may
be to the same degree as is the case with well puddled bar iron into the
reverberating furnace as soon as that degree of decarburisation may be
arrived at, when the required proportions of crude and of decarburised
materials will mix and combine more perfectly at the high and continued
temperature which can be maintained therein than they usually do in
the said converter; the value of my process in great degree consisting
in the much more uniform quality to which the steel or steel iron can
thus be brought, and in the more homogeneous and sound quality of
the castings than can be obtained when cast directly from the Bessemer
or any other converters. Nevertheless in cases where such mixture of
decarburised and crude or non-malleable metals may have been actually
made in such converters or converting vessels, or in cases where by
the nature of any other process or processes of decarburisation which
may have been employed the metallic results may have been brought
into a similar state of steel or of steel iron, as the case may be, the contents
may still be transferred into the reverberating furnace, in which furnace
either with or without such mixture with crude or non-malleable iron
or with decarburised iron as may in any particular cases be, as before
said, necessary, it may be continued sufficiently long for combination
or for settling out the bubbles of gas or air, and then be cast into
sound and homogeneous ingots or castings of the quality and in the
form required. But in every case the quality of the metal to be pro-
duced will be better or worse according as the metallic materials
employed may be such as by their own proper quality and nature are
such as are capable of producing steel and steel iron of better or worse

page_text: quality when used for such production by the more usual
manufacture employed for that purpose.
processes of
Having now described the process or processes to be employed in the
practice of my Invention, I hereby declare that that which I claim as
the substance of my improvements in the production or manufacture
of steel and of steel iron or iron of a steely character is the taking of
the metal whilst still in a liquid state out of any converters or con-
verting vessels or furnaces in which crude or non-malleable cast iron
may have been previously brought into the state of more or less
mallcable iron or of steel respectively by means of blowing through
it atmospheric air or other substances containing oxygen, according to
what is called "the Bessemer process,"
"or such other metal also whilst
still in a melted state as may have been brought into a similar con-
dition by other modes of applying oxygen or substances containing
oxygen thereto beneath its surface, and the transferring either of such
sorts of metal into a suitable reverberating furnace or chamber of some
such kind or kinds as I have herein-before indicated, in which furnace
it is to be brought and maintained at a very high degree of liquid
fusion in combination with whatever mixture or addition thereto of either
crude cast iron or of decarburised or malleable iron it may in different
cases be found requisite to employ for the purpose of bringing the whole
mixture into such a condition as is necessary for obtaining the special
quality or degree of steel or of steel iron intended to be produced, and
by which liquifaction and mixture and the consequent equable inter-
diffusion of the several ingredients and the settling of the whole into
a tranquil and homogeneous condition, ingots or castings will be afforded
more free from bubbles of air or gas, and otherwise of more perfect and
uniform quality than by castings directly from the Bessemer converter
or other converting vessels.
In witness whereof, I, the said Charles Attwood, have to this my
Specification set my hand and seal, the Twenty-ninth day of
August, One thousand eight hundred and sixty-eight.