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May, 1925
Lebanon Drop Forge Shop Burned
The forge shop of the Lebanon Drop Forge Com
pany, Avon, Lebanon, Pa., was destroyed by fire on
the morning of April 8. The loss is estimated at
$80,000. The machine shop and office building of the
company were not damaged. The forge shop will be
rebuilt with steel construction. The fire started in
the roof over a furnace which served a 4,000-lb. hammer.
Company employes manned fire apparatus, but
the water pressure was so low that nothing effective
could be done to save the shop in the face of a stiff
wind that was blowing. One end of the shear shop
was also damaged. Local fire companies devoted their
efforts to saving the remainder of the property. The
plant was busy and about 35 men will be thrown out
of work for the time being.
Electric Heating Unit for Tempering Baths
The General Electric Company recently developed
an immersion heating unit consisting of helicoil sheath
wire cast into iron. This unit was designed for use in
oil tempering baths and melting pots used for melting
lead, tin and alloys which will not attack iron.
The units employed for oil tempering baths utilize
the cast-in feature only on the portion of the sheath
which dissipates heat at the bottom of the tank, while
on the units for melting pots, the cast iron is brought
up on the neck of the unit and out of the pot. This
neck is heated to allow for expansion of the metal
when cold metal is being melted, thus preventing
blow-ups. The cast iron also protects the steel tube
of which the sheath wire is made from corrosion by
the molten metal. The casting is provided with ribs
to increase the radiating surface and to maintain the
temperature of the heating unit at a relatively low
point.
These units are being made in capacities up to 5
kw. and are sold either individually or incorporated
in melting pots and tempering baths.
Detection of Flaws by Magnetic Analysis
The Bureau of Standards has been engaged for
some time in a study of magnetic method for the detection
of flaws and defects in steel, with particular
reference to wire hoisting ropes.
Experiments have been made at the bureau to discover
the cause of the uncertainty in the interpretation
of results, and a method of eliminating it. It has
been found that the greatest source of the difficulty is
the effect of variations in internal stress within the
specimen. Such variations give rise to large differences
in magnetic permeability, which produce effects
similar to and often greater in magnitude than those
caused by the flaws in the material. The result of recent
experiments show that, by the use of higher
values of magnetizing force than have heretofore been
employed, the effect of internal stress is greatly reduced
without a corresponding reduction in the effect
of flaws. It thus appears that one of the greatest difficulties
in the way of the practical application of this
method has now been overcome. The experiments are
being continued to determine whether or not sufficiently
accurate interpretation of the results of magnetic
exploration can be made to permit of its use a*
a practical inspection method.
Forging- Stamping - Heat Treating 185
Reduction in Varieties of Sheet Metal Ware
Simplification committees of the sheet metal ware
industry have begun in earnest the consideration of
what items, among the hundreds of varieties now
being cataloged by that industry, may be eliminated
to the mutual benefit of the manufacturer, distributor
and user. Meetings have been held in connection
with sessions of the Sheet Metal Ware Association of
the United States Chamber of Commerce.
The simplification undertaking is a sequel to a
meeting of the association last summer in French
Lick, Ind., when committees were named. Since that
time progress has been made through correspondence,
but the recent committee meetings have expedited
tentative plans to reduce a large number of items
carried in the catalogs of the various firms.
Attendance at the committee meetings included
Walter H. Blank, American Can Co., Toledo; Sidney
Detmers and C. H. Kent of the Republic Metalware
Company, Buffalo, N. Y.; J. O. Entrekin, Wheeling
Corrugating Company, Wheeling, W. Va.; Thomas
W. Gulley, National Enameling & Stamping Company,
Baltimore; N. W. Judkins, Belmont Stamping
& Enameling Company, New Philadelphia, Ohio;
Fred Morris, Vollrath Company, Sheboygan, Wis.;
George M. Schott, Cincinnati Galvanizing Company,
Cincinnati; W. S. Smith, Sheet Metal Ware Association,
New York; J. H. Stevenson, Lalance & Grosjean
Mfg. Company, New York; C. N. Turner, National
Enameling & Stamping Co., Milwaukee.
Annealing Small Castings with Sawdust
For the benefit of your readers I suggest that the
next time they are confronted with the problem of
annealing castings, particularly small castings which
have been welded and have to be machined, they will
find that dry sawdust has many advantages over
other materials, particularly lime or powdered asbestos.
In the first place a small casting coming in contact
with lime rapidly loses its heat by absorption on
the part of the lime. On the other hand if the same
casting was covered with sawdust the latter instead
of absorbing heat on catching fire starts to create
heat. Combustion would cease when sufficient sawdust
was added to exclude the atmosphere.
iW
In the case of small castings they should be thrown
into a bucket kept half full of dry sawdust, then the
bucket is completely filled with sawdust and as an
extra precaution a cover can be placed on top. For
large castings an excellent plan is to dig a hole in the
ground having a good layer of sawdust and then after
placing the red hot casting in the hole cover with sawdust
and a final cover of earth. My experience is that
a casting of whatever size remains hot much longer
by this than any other means. Sawdust in most places
is obtainable at very little cost and the charred sawdust
adhering to surface of casting is easily removed
which is not the case with lime or powdered asbestos,
etc. I have recommended this wherever I have had
the opportunity and the results obtained by those trying
it have been very satisfactory.—(W. J. Field in
Welding Engineer.)