Improvements in the Manufacture or Conversion of Iron and Steel, and Compounds or Preparations to be used therein.
Year: 1893

page_text: Date of Application, 23rd May, 1893-Accepted, 1st July, 1893
Improvements in the Manufacture or Conversion of Iron and Steel,
and Compounds or Preparations to be used therein.
I JOHN ALEXANDER HUNTER of 715 South 16th Street in the City of
Philadelphia, State of Pennsylvania one of the United States of America Physician
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 :-
One of the objects of my invention is to convert cast iron into steel of good
quality capable of being rolled hammered or drawn like wrought iron or low carbon
steel, or capable of being tempered to form edge tools for instance a further object
being to increase the percentage of carbon in wrought iron or low steel.
My invention as applied to the conversion of iron into steel consists in subjecting
the metal while heated to a high temperature, or even while in a molten state, to
the action of chlorine, oxygen and hydrogen generated, by preference, in the
manner hereinafter described, these gases being brought into contact with heated
carbon before coming into contact with the heated metal, when the invention is
used for the purpose of increasing the percentage of carbon in wrought iron or low
steel.
In treating cast iron for converting it into steel, the iron may be in the form of
castings, bars, ingots, or the like, and should be heated to a yellow or even to a
white heat in a closed crucible or retort in which the aforesaid gases may be
generated, or into which the said gases may be led from an outside generator.
I have obtained good results by introducing muriatic acid, chloride of lime or
bleaching powder (containing hypochlorite) and salt, into the crucible or retort in
which the metal is to be treated, and then closing the crucible or retort and
subjecting it to heat so that the heated iron will be acted upon by the hypochlorous
acid (HC 10) evolved by the action of the muriatic acid upon the chloride of lime,
the result of the treatment being that metal such as ordinary white iron is
converted into a good quality of steel capable of being rolled, drawn, hammered or
tempered.
The chlorine, oxygen and hydrogen gases which constitute the hypochlorous acid
are disunited when the said acid is brought into contact with the highly heated iron
and the oxygen attacks and removes a certain portion of the carbon in the iron, the
hydrogen assisting in this operation and the action of the gases being facilitated by
the presence of the chlorine.
The chemical charge may be heated in a vessel independent of the retort or
crucible in which the treatment of the iron takes place so as to generate the
hypochlorous acid which is conducted into the crucible, but in such case the acid
should not be subjected to any washing, purifying or refining treatment before it
is used.
In treating wrought iron or low steel for the purpose of increasing the percentage
of carbon therein, a certain proportion of carbon, such as vegetable charcoal, may
be added to the charge of muriatic acid, chloride of lime and salt in the crucible or
other vessel in which the hypochlorous acid is generated, or the hypochlorous acid
may be brought into contact with the carbon before it comes into contact with the
heated iron or steel.
In treating molten cast iron the chemical charge is heated in a proper vessel and
the gas is blown into and through the metal in the converter which may be done in
the same way as the air blast is applied in the ordinary Bessemer process, and in
treating molten steel for the purpose of increasing the percentage of carbon therein,
the carbon may either be added to the charge from which the gas to constitute the

page_text: blast is generated, or the gas may be brought into contact with the heated carbon
in its passage from the generator to the converter.
In carrying out my invention the quantities of the various ingredients in the
charge and the duration of the treatment may vary, depending upon the character
of the metal to be treated, and can best be determined by experiment or by analysis
of the metal before treatment, hence I do not desire to limit myself to specific
proportions, but in treating ordinary white iron I have obtained good results by the
use of a charge having, for every 100 pounds of the iron, 24 ounces of muriatic acid,
32 ounces of chloride of lime, and 16 ounces of salt, the treatment continuing for
about two hours after the metal has been brought to the proper heat, and in treating
wrought iron or low steel I have used for every 100 pounds of metal a charge of
about 24 ounces of muriatic acid, 32 ounces of chloride of lime, 32 ounces of
vegetable charcoal and 16 ounces of salt, the treatment continuing for about one
hour after the metal has been raised to the proper heat, and the charge in both
cases being introduced directly into the retort or crucible with the metal.
The effect of the treatment of the wrought iron or low steel with a chemical
charge containing carbon is the material addition of carbon to the metal.
As an instance, I may cite that I have treated metal which originally contained
combined and graphitic carbon to the extent of 0.320 per cent., with the effect of
increasing the combined and graphitic carbon in the treated metal to 1.095
per cent.
The salt may in some cases be omitted from the charge, although its use is
preferred in most cases and especially in the case of iron having a considerable
percentage of silicon.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. The herein described process of converting cast iron into steel, consisting in
subjecting the iron, while highly heated or in a molten state, to the action of chlorine,
oxygen and hydrogen, substantially as herein before explained.
2. The herein described process for increasing the percentage of carbon in
wrought iron or low steel, consisting in subjecting the iron or steel, while highly
heated or in a molten state, to the action of chlorine, oxygen and hydrogen which
have previously been brought into contact with heated carbon, substantially as
hereinbefore explained.
3. The hereinbefore described compound or preparation for carrying out the
process forming the subject of the first claim, the said compound consisting of
muriatic acid and chloride of lime, with or without salt, substantially as hereinbefore
specified.
4. The hereinbefore described compound or preparation for carrying out the
process set forth in the second claim, the said compound consisting of muriatic acid,
chloride of lime and carbon, with or without salt, substantially as hereinbefore
specified.
Dated this 92nd dow of Mo 1802
J. H. JOHNSON & Co.,
Agents.