Steel Ingots and Castings.
Year: 1889

page_text: Steel Ingots and Castings.
I, FERDINAND KNAFFL, Director of the steel factories of Eibiswald and Krumbach
in Styria, Austrian Empire, 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 :-
This invention relates to the manufacture of steel ingots and it has for its object to
avoid the formation of flaws and caverns in the solidifying metal. According to the
invention, the chill-mould with its liquid contents is continually lifted up a short distance
and allowed to drop down again upon a rigid support, whereby the uppermost layer
of liquid metal (the feeding) is repeatedly caused-under the action of inertia-to
rush into the funnel-shaped cavern usually formed in solidifying ingots, and thereby
completely to fill up this cavern.
As will be readily understood, this settling of the liquid steel, repeated again and
again, checks at once the formation of blow holes, as the uppermost layer of the metal
is kept liquid during a longer time, owing to the fact that the continuous concussions
facilitate the ascending of the hottest particles. Thus this layer forms an effective
protection against the contact of the air till the end of the solidifying process and
prevents any oxydation of particles of the inner portion of the ingot. Consequently
the few flaws, which may be formed in the ingot by gas bubbles have not their inner
surfaces oxidized, in consequence of which these surfaces can be welded together.
afterwards when the steel is being worked.
The method described may be used in combination with all those processes of steel
making, the result of which is liquid steel and consequently with the crucible steel
process, the Bessemer process and the Siemens-Martin process. As to the height to
which the chill-mould with its partly liquid contents should be raised each time so as
to be permitted to drop down, the same should be from to of an inch, when small
ingots of crucible steel are concerned, and about half an inch will suffice for the
largest ingots.
It will be readily understood, that various mechanical means may be used for this
alternate raising and dropping down of the chill-mould with its partly liquid contents.

page_text: In the accompanying drawing.
Figure 1 is a sectional elevation, illustrating a very simple arrangement for the
purpose in question. As clearly shown, the chill-mould a rests on a plate b one end
of which is movable round a fixed pivot c while the other end is supported by a
block d of cast-iron or other hard material, and connected by a rod f to a lever In
the case of smaller ingots a ratchet wheel may be used, as shown by dotted lines at h.
It will be understood that the chill-mould a must be firmly secured to the supporting
plate, by means of which it is raised.
g.
Figures 2 and 3 show vertical sections of steel ingots obtained according to the
present and also according to the usual process respectively.
The method hereinbefore described is of special importance for the manufacture of
steel castings, as in such castings honey-combs and caverns are yet more prejudicial
than in ingots. Moreover the use of the said method will be of great advantage in
steel forging, as hitherto ingots of a surplus weight of from 50 to 60 and even of
100 per cent. were required for obtaining satisfactory results.
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 :-
First. A process of preventing steel ingots and steel castings from becoming
honey-comb and cavernous, the said process consisting in alternately lifting the
mould with its partly fluid contents a small distance and dropping it down again
upon a rigid support, in order to cause the mass to settle under the action of inertia.
Second. The combination with a steel casting mould and its partly fluid contents,
of a supporting plate to which the mould is firmly secured and means for alternately
raising and dropping down one end of the supporting plate.
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1 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicant.