Improvements in and relating to a New and Useful Process for Treating Crude or Low Grade Steel to Produce a Refined or High Grade Steel.
Year: 1889

page_text: Date of Application, 5th Feb., 1889
Specification Accepted, 9th Mar., 1889
Improvements in and relating to a New and Useful Process for
Treating Crude or Low Grade Steel to Produce a Refined or
High Grade Steel.
We, HENRY MARTIN REDEMANN, rosiding at No. 259, East Market Street, in
the City of Louisville, County of Jefferson and State of Kentucky, United States of
America, Cutler, and ROBERT JOHNSON TILFORD, residing at No. 125, East Main
Street, in the above named City, County, State and Country, Merchant, do
horeby 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:-
Our invention relates to certain new and useful improvements in the treatment of
crude or low grade steel to produce a refined or high grade steel.
The most successful method of producing low grade steel is that known as the
Bessemer process described in his patent of 1855, but this product as is well known
is suitable chiefly for railways, axles, and like usos, and is totally unsuited for
structures, machinery and tool purposes, unless puddled, hammered and rolled, for
the reason that in its normal state it is too soft, and when hardoned it becomes
too hard and brittle for the purposes stated.
It was the recognition of these inherent defects in the Bessemer and low and medium
grades steel which led us to the investigation of the subject which has developed
our present invention, the object of which is the production at slight cost and a
minimum degree of labor, of a higher grade and more refined steel by treating the
Bessemer and other low and medium grades steel in such manner as to produce a
molecular change from a coarse grain to a fine grain, and silky fracture, to increase
the tensile strength and elasticity, toughness and ductility and to greatly increase
the carbon. We have found from experience that uniform results in all instances
flow from the treatment of metals having like properties.
With these ends in view our invention consists:
In heating the metal to be treated to a white heat, and then submerging the
same in a bath of glycerine and water in the proportion of three (3) ounces of Glycerine

page_text: to one half (gallon Water and allowing it to remain submerged until the change
is effected, which should be until the metal is substantially cool or until such reduction
of heat in the metal is made that it will do no longer to take up the gases generated
by contact with the bath.
We of course do not wish to confine ourselves to the exact proportions named as
they may be varied within reasonable limits and yet produce the samo general
results, but we have found from long experience and repented tests and experiments
that the proportions given produce the best results. It will also be understood that wo
do not wish to confine ourselves to the exact degree of heat imparted to the metal
as that may be varied slightly, so long as the results desired are obtained.
We have of course been unable to analyze the gases resulting from the contact
of the hot metal body with the bath; but are lol to believe that they constitute
a hydro-carbon gas, which has a strong affinity for the metal, and that the latter
being in a heated state is in such a physical condition as to realily takų up or
absorb such gas, but as to the fact that the metal is highly improved we have no
doubt whatever, as has been demonstrated by all the well known scientific and
mechanical tests.
It will be understood of course, that when the treatment is applied adjacent to
the furnaces where the low grade steel is manufactured, the ingots may be treated
without re-heating and thus the expense of such re-heating is avoided. After the
metal has been subjected to the treatment in the bath of glycerine and water it is
allowed to cool in the ordinary manner and it may afterwards be subjected to any
ordinary hardening or tempering process, and the temper may, if necessary, be
drawn and again restored, without at all affecting the other properties acquired from
the bath.
We are of course aware that the quality of Bessemer and other low and medium
grades steel may be improvel by what is known as the dry or cementation process,
which requires a large expenditure of skilled labor and great length of time, and
that too without always securing uniform and satisfactory results.
We dosire it to be distinctly understood that we lay no claim to the broad idea
of increasing the quality of steel by subsequent treatment, as that has been hereto-
fore done, especially by what is known as the cementation process which may be
termed a dry process, our invention differing from such process in the particular that
it requires a period of time amounting to a small percentage of the time required in
the cementation or dry process, and is in contra-distinction to such process, especially
a liquid or wet process. The former requiring many days, while the latter involves
only a few minutes.
As before stated, we wish it to be understood that the chief feature of our process
involves the employment of a bath of glycerine and water, for in the use of these
two bodies, we accomplish desirable and improved results, but the addition to the
glycerine and water of Spirits of Nitro, Aqua Ammonia, Chloride of Ammonium,
Sulphate of Zine, and Sulphate of Alumina and Ammonia, produco better and enhanced
results, hence we do not wish to confine ourselves to the use of a hath embodying
all the bodies named.
Our invention or process is distinguished from processos for temporing steel in oil,
in that by our process the nature, the physical construction of the metal is com-
pletely changed; whereas, the tempering of steel in oil, as practiced by some
procossos, simply tempers the metal more slowly than is done by tempering in water
and other properties, leaving the metal loss hard but somewhat tougher than water-
tompered material. The changes caused by the oil-tempering process are meroly
tomporary, and do not change the physical or granular construction of the metal,
and such changes as are caused thereby can be readily neutralized by re-heating and
allowing the metal to cool. The changes caused by treatment by our process are
permanent, and cannot be removed by any known treatment or process without entirely
destroying the steel properties of the metal by burning.
By our invention we greatly increase the tensile strongth and olasticity, and yet do
not destroy tho per cent. of reduction or ductility. Whilst with ordinary tempering

page_text: the tensile strength and elasticity are greatly increased, but the per cent. of reduction
and ductility are very much impaired.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is―
The process herein described for converting lower grade steel into refined or
higher grade steel, which consists in heating the metal to be treated to a white heat
and then submerging the heated metal in a liquid bath of glycerine and water in the
proportion of three (3) ounces of the former to one half (t) gallon of the latter,
substantially as herein before set forth.