Los Angeles herald. [microfilm reel] (Los Angeles [Calif.]) 1900-1911, 1908-12-28
AUTOGENOUS WELDING
is STRONG RIVAL OF
ELECTRICAL PROCESS
Cast Iron and Aluminium Susceptible
to Welding, as High Temperature
Fuses Metals at Point of
Contact

Autogenous welding is the uniting of
metals by heat alone, without pres
sure-as is used by the ordinary black
smith, and usually applied with a
hammer, and without the use of a
f1ux or another metal-as in brazing
and soldering.
The most common apparatus for this
purpose is one in which the heat is
produced by burning acetylene with
pure oxygen, in hand torch giving a
welding flame varying in size from
about one-sixteenth to one-fourth inch
in diameter depending on the size OF
the tip, a number of which are sup
QuiIed by the size and thickness of the
part to be welded This flame has a
temperature of about $500 degrees
Fahrenheit, which is about the same
as that of the electric arc, and upon
its application to any metal fusion
very soon takes place, the extent of
which is noted by the operator, who is
guided accordingly in the movement
of his torch. The metal at the point of
fusion flows together and is practical
ly "recast locally" metal being added
where necessary from a rod of the
same material as the part being weld
ed. This applies to all metals, includ-
ing cast iron and aluminium. These
two metals are mentioned particularly
sidered to be weldable, and therefore
serve the better to show the magni-
tude of this development, particularly
when it is considered how brittle they
are and how subject to mishap.
Like the motor car, autogenous weld
ing owes Its early development to
France. At the end of last year there
were over 800 plants in operation in
that country. The whole secret of the
process lies in the high temperature of
the flame, which raises the tempera-
ture of the metal so rapidly that very
little heat is diffused into the body of
the part. Most Of 1t, therefore, being
available for fusion. The number OF
heat units actually absorbed by the
metal is a very small fraction of that
required to bring the same part to a
brazing heat, with the ordinary gas
or oil blowpipe and very little, If any,
warping takes place.
Flame Must Reach All Parts of Joint
One of the first points to be under
stood, when considering autogenous
welding of any part, is, that the flame
has actually to come in contact with
every drop of metal welded; and that
it is impossible to weld in places where
this cannot be done. For Instance; If
q small boss is required on casting,
it is useless to cut out disk OF metal
the size OF the boss with the idea of
welding 1t on. The correct way would
be to add metal, drop by drop, until
the required size is reached, and If the
shape is of Importance, extra metal
must be added and machined off to the
correct size.
Metal up to one-eighth inch in thick
ness can be "butted," the heat passing
down the opening being sufficient to in
sure it's welding through. Above this
thickness the sides must be beveled off
allowing the welding flame to penetrate
to the bottom of the joint. The opera
tor then notes the flow of the metal
right from the bottom and fills up the
groove accordingly. In welding a crack
in metal over one-eighth inch in thick
ness II is necessary to cut a groove, or
opening. which viii allow welding right
through. The growing is usually done
by grinding, but sometimes by clipping,
filling, milling or saving. When bevel-
ing a broken part care must be taken
to leave sufficient of the original break
to line up the parts with; 1t generally
being desirable to leave three short Sec
tions on each fragment for this pur-
pose.
1t win be realized that it is impos-
sible to make a lap weld, with this APP
paratus: therefore, when 1t Is required
brazed. as, for example, the joints of
the exhaust manifold made from steel
tubing, 1t win be necessary only to fit
the two tubes so as to butt together
a. they should not be Hanged, as for
brazing. The fianges and other fittings
will only be welded at the edge, either
outside. inside or both, as found most
1t being only necessary to
weld around at one place.
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