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, residing 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 hereby
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 stoel 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 1885, but this product as is well known
is suitable chiefly for railways, axles, and like uses, 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 hardened 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, 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, having added thereto, Spirits of Nitre, Aqua
Ammonia, Chloride of Ammonium, Sulphate of Zinc, Sulphate of Alumina and
Ammonia, substantially as will hereinafter be more particularly set forth.

page_text: Aqua Ammonia one and a half (14) ounces.
Chloride of Ammonium two (2) ounces.
Sulphate of Zine one and a half (14) ounces.
Sulphate of Alumina and Ammonia one and a half (14) ounces.
Glycorino three (3) ounces.
Water one half (1) gallon.
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 same general
results, but we have found from long experience and repeated tests and experiments
that the proportions given produce the best results. In preparing the bath we
preferably first powder or granulate the chemicals and mix the same thoroughly and
intimately with the glycerine until well dissolved and we then add to the bodies so
compounded, the necessary quantity of water. It will also be understood that we 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 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 readily take up or
absorb sneh gas, bar as to the fact that the metal is highly improvel 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 nadjacent 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 treatinent in the hath described, 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, he drawn
and again restored, without at all affecting the other properties acquired from
the baib.
We are of course aware that the quality of Bessemer and other low and medium
grades steel may be improved by what is known as the dry or cementation process
which requires a largo expenditure of skilled labor and great length of time, and that
too without always securing uniform and satisfactory results.
We desire 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 heretofore
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,
essentially a liquid or wet process. The former requiring many days while the
latter involves only a fow minutes.
As before stated we wish it to be understood that the chief feature of our process
involves the employment of a bath having as its lase 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 Nitre, Aqua Amnonin, Chloride of
Ammonium, Sulphate of Zinc and Sulphate of Alumina and Ammonia produce botter
and enlanced results, hence we do not wish to confine ourselves to the uso of a bath
embodying all the bodies namod.
Our invention or process is distinguished from processes for tempering stoel in oil,
in that by our process the nature, the physical construction and the molecular or
granular construction of the metal is completely changed; whereas, the tempering of

page_text: steel in oil, as practiced by some processes, 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-tempered material. The changes caused by the oil-
tempering process are merely temporary, 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 strength, and elasticity, and yet
do not destroy the per cent. of reduction, or ductility. Whilst with ordinary
tempering 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 steel, which consists in first heating
the metal to be treated to a white heat and then while so heated, submerging the
same in a liquid bath consisting of glycerine and water, in the proportion of three
ounces of the former and one half gallon of the latter, combined with Spirits of Nitre
one and a half ounces, Aqua Ammonia one and a half ounces, Chloride of Ammonium
two ounces, Sulphate of Zinc one and a half ounces, Sulphate of Alumina and
Ammonia one and a half ounces, substantially as hereinbefore set forth.
HENRY MARTIN REDEMANN.
ROBERT JOHNSON TILFORD.
By Jensen & Son,
77, Chancery Lane, London, W.C.,
Patent Agents.