Year: 1886

page_text: I JOHN THOMSON KING, of 4 Clayton Square, Liverpool in the County of
Lancaster, Patent Agent do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
In the Bessemer process of manufacture of steel, it is usual, after the charge
has been blown in the converter, to add to the molten charge a supply of manga-
nese or spiegeleisen to effect the recarburization of the metal. This addition is
made just before the casting of the charge, either before its removal from the
converter or after it has been poured thence into the ladle, and great difficulty has
been experienced in causing the proper mixture of the manganese with the metal.
The result of an imperfect mixture is a steel uneven in its composition and of
lessened utility. The mixing has been effected generally by mechanical means,
such for example as by a blast of air, or by a rabble, but such process is unsatis-
factory because it is at best incomplete and entails hard labor and considerable
expense.
I have discovered that the manganese may be mixed with the charge by the
addition of limestone, thereto, either just before, or after, or simultaneously with
the manganese addition. The result of this treatment is to cause a violent ebullition
and agitation of the metal, which intimately commingles the iron and manganese
together, and upon casting, the ingots will be found to homogeneous in their
structure. This effect is not produced by the presence of lime in the usual basic
lining of the converter. In practice I prefer to place the limestone and manganese
in the ladle and to pour the molten metal from the converter into it, since in this
way the agitation is more thorough and immediate, but I do not desire to limit
myself to the time and manner of the treatment, except that it must be done at
about the time of introducing the manganese,
The use of this process cheapens the manufacture of steel by reason of the fact,
that it lessens the quantity of manganese which need be employed to carburize a
viven charge of metal.

page_text: I have stated that I employ limestone in my improved process. There is a
peculiar form of this mineral, however, which I prefer to use, because its effect
on the metal is not only to carburize it uniformly by the thorough admixture of
the manganese, but it otherwise greatly improves the quality of the resultant
product by rendering it tougher and more tenacious and by the elimination of
phosphorous and silicon, and by its own carburizing effect.
This mineral is a calcareous marl found in the western part of Pennsylvania,
United States of America, and its chemical analysis is substantially as follows:-
I do not desire to confine myself to any particular theory of operation of this
substance, but I belive that the carbonates, when in contact with and calcined by
the heat of the molten iron, give up their carbon thereto, and thus facilitate the
carburization of the charge and enable it to be performed with the use of much
less ferro-manganese than has commonly been employed. The process is thus
much cheapened, and the resultant metal is more tenacious and of better quality
than if this calcareous marl be not employed.
I do not desire to claim broadly the use of limestone with molten metal, or lime,
or limestone with manganese, but limestone has not heretofore been employed, for
the agitation of the bath of metal, as herein described.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1.-In the art of making Bessemer Steel, the process of intimately mixing the
manganese with the molten metal, by means of carbonate of lime introduced at
the same time, or nearly at the same time, with the manganese addition: substan-
tially as and for the purposes described.
2. An improvement in the process of making steel, which consists in the treatment
of the molten metal with a mineral whose composition is substantially as herein-
before described.
3. In the art of making Bessemer Steel, the process of intimately mixing the
manganese with the molten metal, which consists in the addition of carbonate of
lime to the charge of refined metal, by placing the carbonate of lime in a ladle
and then pouring the molten metal thereupon: substantially as and for the
purposes described.