IMPROVEMENTS IN THE MANUFACTURE OF STEELS OR STEEL-LIKE METALS
Year: 1879

page_text: LETTERS PATENT to Richard Brown, of Ayr, in the County of Ayr, North
Britain, Manufacturing Chemist, for the Invention of "IMPROVEMENTS IN
THE MANUFACTURE OF STEELS OR STEEL-LIKE METALS."
Sealed the 23rd May 1879, and dated the 27th February 1879.
PROVISIONAL SPECIFICATION left by the said Richard Brown at the Office
of the Commissioners of Patents on the 27th February 1879.
RICHARD BROWN, of Ayr, in the County of Ayr, North Britain, Manufacturing
Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF STEELS OR STEEL-LIKE
METALS."
This Invention has for its object to obtain improved qualities of steel or steel-
like metals by processes which are applicable to various qualities of castiron, and
it consists mainly in combining with the iron chromium, or tungsten, or manganese,
or any two or all three of these metals, the combination being brought about by
mixing with the castiron when in a melted state certain salts or compounds of the
said metals, which compounds whilst facilitating the attainment of the main object
are also expected to have the effect of eliminating impurities, such for example as
phosphorus and sulphur from the iron when such impurities are present.
The compounds to be used in carrying out the present Invention are bichromates
of potash and soda, chromates of potash, soda, lime, and magnesia, chromic acid,
sesquioxide of chromium, permanganates, and manganates of potash and soda, and
tungstates of potash and soda.
In carrying out the Invention, castiron, or it may be partially formed steel, which
may have been previously treated in any known way, may for the purposes of this
Invention be contained in a converter, such as is used in the Bessemer process, or
in a reverberatory furnace, or in a crucible, or in any furnace or vessel in which it
can be conveniently held in a suitable molten state. The bichromate of potash or
other compound or compounds may be added by being blown in in powder by a

page_text: blast applied as in the Bessemer process, or it may be simply mixed into the molten
metal; it should however in all cases be thoroughly intermixed, and the tem-
perature should be such as to keep the metal sufficiently fluid for the mixing to be
effectively performed.
The proportion of bichromate of potash or other compound will vary in each case
with the particular qualities of steel desired, and also with the proportion of the
impurities present in the iron, smaller proportions being used for milder or more
ductile steels, and larger proportions for harder steels. It is believed that five parts
by weight for every hundred parts of the iron will be a proportion yielding a hard
steel, and that in general smaller proportions will be found to answer best.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Richard Brown in the Great Seal Patent Office on the 26th August
1879.
RICHARD BROWN, of Ayr, in the County of Ayr, North Britain, Manufacturing
Chemist. "IMPROVEMENTS IN THE MANUFACTURE OF STEELS OR STEEL-LIKE
METALS."
My said Invention has for its object to obtain steels or steel-like metals of
improved qualities by processes which are applicable to various qualities of cast or
other iron, or to partly converted iron or inferior steel; and it consists mainly in
combining chromium with the iron or metal operated on, the combination being
brought about by mixing therewith when in a melted state certain salts or com-.
pounds of chromium, which compounds whilst facilitating the attainment of the
main object will also have the effect of eliminating or neutralising impurities, such
for example as phosphorous and sulphur when such impurities are present.
The compounds to be used in carrying out my Invention are bichromate of
potash and soda, chromates of potash, soda, lime, and magnesia, and sesquioxide
of chromium. Of these compounds I believe the bichromates to be the most
advantageous, and I prefer to employ the bichromate of potash, especially when
the metal operated on contains phosphorus.
In carrying out my said Invention the iron or metal to be operated on, and
which may if found desirable have been previously treated in any known way,
may be contained in a converter, such as is used in the Bessemer process, or it may
be contained in a reverberatory furnace, or in a crucible, or in any furnace or vessel
in which it can be conveniently held in a suitable molten state. The bichromate
of potash or other compound or compounds may be added by being blown in in
powder by a blast applied as in the Bessemer process, or it may be simply mixed
into the molten metal; it should however in all cases be thoroughly intermixed, and
the temperature should be such as to keep the metal sufficiently fluid for the
mixing to be effectively performed. The powdered material may be introduceḍ
into the blast pipe of the Bessemer converter by means of a small hopper com-
municating with the pipe by a descending passage fitted with two valves, the
material being first admitted into the space between the valves, and after closing
the upper valve allowed to descend gradually by opening the lower valve. Or
the material may be introduced into the metal from the mouth of the convertor,
the blast being stopped during the introduction, and afterwards renewed for a few
minutes in order to effect a thorough mixture. When adding the material in a
reverberatory furnace, or crucible, or other vessel, it may be in powder or in small
pieces put up in several paper bags or other wrappers, which will afford a slight
protection whilst it is being introduced, and whilst introducing the material the
slag must be pushed aside by means of an iron rod or other instrument. When the
metal is in a crucible the cover must be kept more or less open for a short time
after adding the material in order to allow of the escape of gas; and the crucible
should be kept in the furnace for about fifteen minutes after closing the cover.
The selection of bichromate of potash or other compound or compounds, and the
proportion thereof to be employed will vary in each case with the particular
qualities of steel desired, and also with the kind and proportion of impurities
present in the iron or metal operated on. When the iron or metal to be operated
on contains much carbon, the excess of carbon should be eliminated by means of
the Bessemer or other adequate process before treating the metal according to my
present Invention.
Taking for example castiron containing 75 per centum of phosphorus and a
variable quantity of carbon, the proportion of carbon should be reduced to about .2
per centum, and about 75 per centum of bichromate of potash should be mixed

page_text: with the melted metal; this will yield a ductile steel. A larger proportion of
bichromate of potash will give a harder steel. Only a portion of the phosphorous is
in practice found to be removed, but when the proportion of carbon is small or is
reduced as above directed, the phosphorus remaining in the metal no longer has
injurious action, nor imparts undesirable qualities, but on the contrary improves
the metal, more particularly by rendering it capable of being cast in a solid
condition, and free or nearly so from cavities or holes. With a larger proportion of
phosphorus present in the metal than that given in the above example, the steel
will be harder, other things remaining the same. When the proportion of
phosphorus is less than that given in the example, a larger proportion of carbon
may be retained, and similar results may be obtained with a smaller proportion of
bichromate of potash.
After the iron or metal has been treated as hereinbefore described, spiegeleison,
or ferro-manganese, or peroxide of manganese, may be added to it, but in many
cases this will not be necessary.
In my Provisional Specification relative hereto compounds of tungsten and
manganese are mentioned amongst those I proposed to use, but I do not now desire
to claim the use of those compounds.
Having thus particularly described my said Invention, and the manner of
performing the same, I have to state that I do not restrict myself to the precise
details herein described, but that what I believe to be novel and original, and
claim as the Invention secured to me by and in terms of the herein before in part
recited Letters Patent is,-
The manufacture of steels or steel-like metals of improved qualities by mixing
any one or more of the compounds of chromium herein before specified with cast or
other iron, or partly converted iron, or inferior steel, substantially in the manner
herein before described.
In witness whereof, I, the said Richard Brown, have hereunto set my hand
and seal, this Twenty-fifth day of August, in the year of our Lord One
thousand eight hundred and seventy-nine.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
RICHARD BROWN. (LS.)