Method of Hardening Steel Tubes Internally.
Year: 1889

page_text: Date of Application, 29th Aug., 1889
Complete Specification Left, 31st Dec., 1889-Accepted, 1st Feb.,
1890
PROVISIONAL SPECIFICATION.
Method of Hardening Steel Tubes Internally.
A communication from abroad by MORITZ KRAMER, of Chausséestrasse, 1, Berlin,
Merchant.
I, WILLIAM LLOYD WISE, of No. 46, Lincolns Inn Fields, in the County of Middlesex,
Consulting Engineer and Patent Agent, do hereby declare the nature of this invention
to be as follows:-
The present invention has for its object the hardening internally of steel tubes of
any diameter. It is well known that the methods heretofore usually employed are
not suitable for hardening steel tubes of small internal diameter, or where it is required
that the tube, even though very thin, shall not warp at all during hardening.
To effect the purpose in view it is necessary to heat and also to cool the tube
uniformly throughout its length. For this purpose the following method is
employed.
The tube to be hardened is connected to a vessel filled with water, cold air or
carbonic acid or other liquid or gaseous cooling substances under considerable
pressure. Between the tube and the said vessel is provided a cock that enables
communication with the interior of the vessel to be opened and closed as required.
On the tube to be hardened, near to each of its ends, is placed a collar or clamp ;
each of these is in conductive connection with one pole of an electric battery or other
source of electricity.
When the hardening is to be effected, there is first passed through the tube an
electric current of a strength sufficient to heat the tube to the temperature suitable
for hardening. The current is then suddenly interrupted, and the cock before-
mentioned is opened, so that the current of cold liquid or gas flows through the tube.
In this way uniform hardening of the interior of the tube is effected.
Doted this n0th day of August 1889
COMPLETE SPECIFICATION.
Method of Hardening Steel Tubes Internally.
A communication from abroad by MORITZ KRAMER, of Chausséestrasse, 1, Berlin,
Merchant.
I, WILLIAM LLOYD WISE, of No. 46 Lincolns Inn Fields, in the County of Middle-
sex, Consulting Engineer and Patent Agent, do bereby 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 :-
The present invention has for its object the hardening internally of steel tubes of
any diameter.
It is well known that the methods heretofore usually employed are
not suitable for hardening steel tubes of small internal diameter or where it is required
that the tube even though very thin shall not warp or become distorted at all during
the hardening process.
To effect the purpose in view it is necessary to heat and also to cool the tube
uniformly throughout its length. For this purpose the following method is
employed.
The tube to be hardened, marked R in the accompanying drawing, is connected
to a vessel G filled with water, cold air or carbonic acid or other liquid or gaseous
cooling substance, at a high pressure. Between the tube and the vessel G is pro-
vided a cock H that enables communication with the interior of the vessel to be
opened and closed as required.

page_text: On the tube to be hardened, near to each of its ends, is placed a collar or clamp S
each of these is connected with one pole of an electric battery B or to an electric
machine.
When the hardening is to be effected there is first passed through the tube an
electric current of such intensity that the tube is heated to a temperature suitable for
hardening. The current is then suddenly broken, and the cock H is opened, so that
the current of cold liquid or gas flows through the tube. In this way uniform
hardening of the interior of the tube is effected."
In lieu of breaking the electric current the collar or clamp S close to the vessel G
may be slowly moved upon the tube towards the other collar or clamp whilst the
cooling substance is at the same time passing through the steel tube.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is -
The hereinbefore described method of internally hardening steel tubes of any
diameter the said method consisting in heating the tube by the passage through it of
an electric current, and then suddenly cooling it by a suitable liquid or fluid
delivered under pressure from a reservoir to which the tube is connected, the
electric current being previously broken or shunted, substantially as described with
reference to the drawings.
Dated th: 0111
T