Improvements in the Manufacture of Steel.
Year: 1890

page_text: Date of Application, 25th Feb., 1890-Accepted, 29th Mar., 1890
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Steel.
We, MARTIN FRANCIS COOMES, Physician, and ARUNAH WATERMAN HYDE, Chemist,
both of Louisville in the County of Jefferson, State of Kentucky, and United States
of America 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 stateinent :-
Our invention relates to the manufacture of steel, and its object is to effect a
cheap and rapid carburization of malleable cast iron, or of low carbon steel, by the
use of certain carbon compounds which are readily decomposed by contact with the
heated metal to be carburized. whereby the carbon is set free and unites with
the metal, thus converting the malleable cast iron into steel, or the low carbon steel
into high-carbon steel.
To carry our invention into effect, we employ any of those substances which in
the science of chemistry are known as carbo-hydrates, which are rich in carbon,
combined with bydrogen and oxygen, the latter being in the proportion to form
water; including the sucroses (cane sugar, etc.,) glucoses, (grape sugar etc.) and
amyloses (starch etc.).
Suitable carbo-hydrates for our process are sugars of any kind, syrups of any
kind, molasses or treacle or other liquid residues of sugar making, and honey. The
carbo-hydrates may be used in a pure state, or mixed with such substances as convert
them into carbonic or carbonaceous compounds, such as alkalies, alkaline carbonates,
or mineral acids.
As an equivalent and substitute for the above, we employ any of these organic
acids which result from the oxidation of what are termed in the science of chemistry
the glycols. These are divided into two groups, which are known as the lactic acid
series and the oxalic acid series. They also contain carbon in combination with
hydrogen and oxygen, and are readily decomposed by the application of heat.
The alkaline salts of the acids named, which are soluble in water, are the equivalent
of the acids for our process.
Oxalic acid, tartaric acid, and the alkaline salts of these acids are good examples of
substances useful and available for our process.
Of
any of these substances or mixtures we form a bath, by dissolving it, if in a
solid state, in any quantity, in water or in milk. Milk of any kind, either in a pure
state or mixed with water may be used alone to constitute the bath, as this of itself
under various conditions contains sugar or lactic acid, or other source of carbon in
sufficient quantity to carry our invention into practical effect and to an available
extent for some purposes.
In this bath is placed the metal, raised to a white heat, where it is allowed to
remain while cooling. The metal parts with its heat, which decomposes the carbo
hydrate, the hydrogen and oxygen forming water; whilst the carbon which is thus
set free, is absorbed by and chemically unites with the metal.
In our process the carbo-hydrates, or the acids or other sources of carbon, may be
employed either singly or mixed together, and in any desired quantity to supply the
requisite carbon, a deficiency or surplus or carbon affecting the extent and economy,
but not the completeness, of the carburization. A quantity insufficient to convert
the whole mass will case harden it, if case hardening is desired, or the metal may
be re-heated and the process repeated.
When desired, before placing the metal in it, the bath may be heated to any
extent short of decomposing it.
The carrying out of our process by the use of carbo-hydrates mixed with alkalies,
alkaline carbonates, or suitable mineral acids as oxidizing agents, possesses this
[P7]

page_text: advantage, namely; that the mixtures are by the application of heat converted into
other carbonic or carbonaceous compounds, which by additional heat are readily
decomposed into lower carbon compounds, yielding the excess of carbon to the metal
to be carburized. Thus, certain carbo-hydrates when heated with either nitric acid, or
the caustic alkalies, are oxidized and converted into saccharic, oxalic, tartaric and
other acids, which in turn are decomposed by the heated metal and yield up carbon to
it. For the purpose of our process, therefore, these mixtures are equivalents, their
action under the application of heat being chemically identical.
We have found by experiment that the following baths give excellent results,
viz.:
1. Sugar or molasses, one pound, water, one gallon.
2. Sugar, one ounce; condensed milk, one pound, water one gallon.
3. Honey, one pound; water, one gallon.
4. Sugar or molasses, one pound; caustic potash or soda, one ounce; milk, one
pint, water one gallon.
5. Cream of tartar, four ounces; oxalate of potash, four ounces, water one
gallon.
6. Milk, or condensed milk, one pound, water one gallon.
Oxalic acid is of especial value in carrying our invention into effect being one
of the cheapest and most efficaceous substances for the purpose.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed we declare that what
we claim is :
1. In the manufacture of steel, the process of carburizing malleable cast iron and
low carbon steel which consists in placing the metal raised to a white heat, in a
bath composed of water or milk containing a carbo-hydrate or organic acid
equivalent source of carbon or consisting of milk, substantially as set forth.
2. In the manufacture of steel the process of carburizing malleable cast iron, or
low carbon steel, which consists in placing the metal raised to a white heat, in a bath
containing oxalic acid, substantially as described.
3. In the manufacture of steel, the process of carburizing malleable cast iron or
low carbon steel, which consists in placing the metal, raised to a white heat, in a bath
composed of water or milk, and a sugar, substantially as set forth.
4. In the manufacture of steel, the process of carburizing malleable cast iron or
low carbon steel which consists in placing the metal, raised to a white heat, in a
bath formed by adding to water or milk a mixture composed of a sugar, or other
carbo-hydrate, and a caustic alkali, or oxidizing agent, substantially as set forth.
— OKT 1000
MARTIN FRANCIS COOMES.
ARUNAH WATERMAN HYDE.
By Harris & Mills,
23, Southampton Buildings, London, Agents.