Improvements in Compounds for Converting Iron or Low Grade Steel into High Grade Steel by the Cementation Process.
Year: 1893

page_text: Date of Application, 17th Feb., 1893-Accepted, 15th Apr., 1893
COMPLETE
SPECIFICATION.
Improvements in Compounds for Converting Iron or Low Grade
Steel into High Grade Steel by the Cementation Process.
I, FRANCIS GORDON BATES of No. 2027 North College Avenue in the City of
Philadelphia State of Pennsylvania United States of America Mechanical
Engineer 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 :-
My invention consists of certain improvements in the compound for converting
iron or low steel into high grade steel by the cementation process for which Letters
Patent No. 7820 were granted to me and dated May 20th 1890 the improvements
consisting mainly in the addition of black oxide of manganese or nickel oxide, or
both, to the patented compound, but including also certain minor additions and
changes as hereinafter set forth.
The patented compound consisted of from 80 to 100 parts of carbon, such as
pulverised charcoal, still coke or the like, and from 5 to 10 parts of cryolite to
which was sometimes added from 10 to 20 parts of hydrated lime, and from
5 to 10 parts of rosin or carbonate of soda.
To these ingredients I now add black oxide of manganese or nickel oxide, or
both, in quantity depending upon the desired percentage of manganese or nickel
in the finished product, and I also, in some cases, increase the percentage of
cryolite to 15 parts or more and add a small quantity of salt or salt-petre, or both,
and from 5 to 10 parts of pulverized alum.
In treating Bessemer or open hearth steel or wrought iron the compound may
consist simply of the carbon, cryolite and oxide of manganese, or nickel oxide, or
both, although the process is facilitated by the addition of the salt or salt-petre,
hydrated lime and alum, the rosin and soda being as in the former case, added
when cast iron or malleable iron is under treatment, although not absolutely
necessary even in that case.
The following is a sample of a compcand according to my invention which
answers well in practice for converting Bessemer billets into high grade steel;
90 parts (by weight) of carbon, 10 parts of cryolite, 20 parts black oxide of
manganese, 2 parts of salt or salt-petre (or one part of each) 10 parts of hydrated
lime and 10 parts of ground alum.
Where a nickel steel is desired the nickel oxide may take the place of the
manganese oxide, or both the nickel oxide and the manganese oxide may be used
and the proportion of either oxide used may be greater or less than that given,
depending as before stated, upon the desired percentage of manganese or nickel
which is desired in the finished product.
The process may be carried out in the same manner as that set forth in my
former Patent, that is to say, the billets are packed in a box, flask or other
receptacle of refractory material so that each billet is surrounded by the compound,
the flask when full being closed so as to be air-tight and then subjected to heat in a
suitable oven in which the temperature is raised to about 1500° or 2000° Fahrenheit
or until the flask or receptacle has reached a bright red heat, at which
heat it is maintained for about seven days, it being understood that the length of
treatment will vary according to the bulk of the article under treatment or upon
the desired extent of the conversion, the length of treatment, as well as the number
and proportion of the ingredients employed being determined largely by the skill
and experience of the metallurgist in charge of the operation.
In many cases it is preferable to permit the flask to become cool before removing
the articles therefrom.

page_text: In some cases the proportion of salt and salt-petre can be increased and the
proportion of cryolite correspondingly diminished, and, as in the former case other
fluorides having substantially similar properties may be substituted for the cryolite,
and other hydrates for the hydrated lime.
I find that ordinary Bessemer or open hearth steel treated in accordance with my
invention produces a steel which is especially available for the manufacture of
armour plate and projectiles, as it can be tempered to a high degree, while its
ductility and tensile strength are greater and its cost is less than in the case of
ordinary nickel steel plates or projectiles.
I have also found by repeated experiments that low steel or iron treated in
accordance with my invention shews by analysis after treatment, considerable
percentages of carbon, manganese or nickel, or both, when both oxides are employed,
the steel being of a superior character and capable of receiving a temper which
will stand a high temperature without being drawn, hence tools made of the
improved steel can be used for very hard work without any impairment of their
quality.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is ;-
The within described compounds for converting iron and steel the said compounds
consisting of carbon, cryolite and oxide of manganese or of nickel or both such
oxides and either with or without the addition of salt or salt-petre, lime or alum,
or all of them substantially as hereinbefore specified.
Dated this 17th day of February 1202
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.