IMPROVEMENTS IN THE MANUFACTURE OF STEEL
Year: 1884

page_text: I, JAMES J. MOTIGHE, of Pittsburgh, in the County of Allegheny, in the State
of Pennsylvania, one of the United States of America, Clergyman do hereby
declare the nature of said Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF STEEL
and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
"
This Invention relates to the manufacture of steel, and is applicable to the
production of various grades thereof.
or
It is commonly supposed that the brittleness of iron, or steely irons, is due,
according as the iron is hot or cold, to the presence of an excess of sulphur or
phosphorus. Discarding this theory, and assuming that the "cold-shortness
"red-shortness" of iron or steel is due principally to an admixture of oxide of iron,
I have devised a new method or process of manufacturing carburized iron, by
means of which, even though both sulphur and phosphorus be in excess in the
metal, it is rendered exceedingly ductile, especially when only a low grade steel.
Hitherto in the manufacture of ordinary steel of low grade, such for instance as
is used for rails, boiler-plate or the like, it has been customary to desiliconize, aud
decarburize molten cast-iron, by blowing free air through or over it. I maintain
that this air leaves oxide of iron mixed with the mass.
My Invention has for its objects to rid the entire mass of metal of all this
injurious oxide, as well as to carburize it to the required degree, as also to further
purify it by the extraction of phosphorus, sulphur and the like, and to these ends
my Invention consists in subjecting the molten iron to the action of a hydrocarbon
gas or vapor, substantially as hereinafter described.
I prefer to blow the said gas or vapor through the molten iron in a converter in
a manner similar to that in which air is blown through in desiliconizing in the
Bessemer process, though it may be done in a variety of ways.
The rationale of the process is as follows:-The gas or vapor dissociates the
instant it comes into contact with the molten iron, the carbon and hydrogen both
assuming the nascent state. Carbon, having in the presence of heat a great affinity
for oxygen, deoxydizes the oxide; hydrogen on account of a similar affinity assists
in this reaction; and the two fold product (carbonic oxide or acid and hydric
oxide) pass off as waste. This reaction developes considerable heat and serves to
continue the metal in its molten condition, effectually preventing chilling in
the converting vessel. Simultaneously a further quantity of nascent bydrogen
chemically combines with portions of the sulphur and phosphorus, and forms

page_text: respectively sulphuretted and phosphoretted bydrogen, which pass off as waste,
thus further purifying the product. At the same time, a certain quantity of the
nascent carbon unites with the molten mass of iron to form steel, which will be of
a high or low grade according to the duration of the described reaction.
Thus all necessity of using spiegel-iron, and other similar materials, is obviated,
and a fine quality of excellent steel is produced by the sole action of hydrocarbon
vapor or gas on a mass of molten iron.
This process serves also for the production of fine tool steel from poor qualities of
pig-iron. Hitherto in the manufacture of fine tool-steel, it has been necessary to
blister bar or wrought iron and remelt in a crucible, in order that the carbon,
which in the process of blistering penetrated scarcely beyond the surface, might be
equally distributed throughout the molten mass, so as to make it homogeneous, in
which condition it was ready for casting. The operation is very slow and costly,
requiring generally at least seven days for its completion. By my process,
however, in as many minutes I can produce an article in nowise inferior.
I do not confine the scope of this Invention to the production of any particular
quality or grade of steel; nor to any specific method of subjecting the molten iron
to the action of the hydrocarbon gas or vapor; nor do I limit myself to any particular
carboniferous gas. In some localities "natural gas" will be accessible and serves
admirably. In others the gas or vapor may be generated from hydrocarbon
liquids or solids.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare that what
I claim is
First. The process of manufacturing steel consisting in subjecting iron, while
in a molten state, to-the-action of a hydrocarbon gas or vapor, substantially as
described.
Second. The process of manufacturing steel by first melting cast iron, then
burning out its silicon and carbon with air, and finally, while still molten,
recarburizing the iron by subjecting it to the action of a hydrocarbon vapor or gas,
substantially as described.
Third. In the manufacture of steel the process of recarburizing decarburized iron
by forcing a hydrocarbon gas or vapor through the iron while the latter is in its
molten state, substantially as described.
Dated this 15th love of Aunit 7001
HASELTINE, LAKE & Co.,
For the Applicant.