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332 Forging- Sf amping - Heaf Tieating
in place, the guides can be quickly and easily removed
or replaced. If it is necessary to remove the ram
from the hammer to dress up the die notch, this is
easily done by removing the guides as has just been
described and then dropping the ram and removing it
from the hammer almost at floor level without dismantling
the hammer or even spreading the frames
apart. Other advantages of this construction are that
it is possible to renew the guides in just a few minutes
if a spare set of guides is carried. After the Ys have
been worn they can be dressed up in a small planer; a
large planer capable of passing the whole frame of
the hammer is not required, nor is it necessary to completely
dismantle the hammer. Moreover, by having
only hall of the guides renewable, only half the length
has to be planed that would otherwise be required,
since the single V at the top should last for the life
of the hammer without dressing it up.
As is the case with all Erie Drop Hammers, the
upper works of the hammer form a rigid unit which
can be moved across the anvil from right to left or vice
FIG. 3—Showing the novel type of guide construction.
versa, being moved by adjusting wedges which bear
across the back of the frames for the full width. In
addition to these wedges, provision is made for taking
up wear between the frames and the anvil in the
front and back direction. The overhang of the frame
bears against the back face of the anvil, and at the
front tapered gibs are provided lying on the front
face of the anvil under the over-hanging frame, so
that as wear occurs, the tapered gibs can be tightened
up and the proper fit maintained. This construction
has eliminated the necessity for the tongue and groove
which is usually provided to keep the frames in line
with the anvil and thus it has been possible to provide
September, 1925
an unusually large area at the top of the anvil where
the frame is seated, and it is expected that wear at
this point will practically be eliminated. The latch,
roll release lever, treadle and other similar parts, follow
the well known design of standard Erie Board
Drop Hammers.
Application has been made for patent covering the
special features of the hammer, which have been described
above.
Cause of Blisters
Sample iron plates cast from northern pig irons
were distributed to co-operating enamelers and also
enameled in the Bureau of Standards laboratory. Both
lots of sample plates were found to blister if enameled
above a fairly definite temperature; that is, about 1290
deg. F., according to Technical News Bulletin No. 99,
issued by the bureau.
The three most probable causes of the blisters are
as follows: A certain amount of gas is taken up in
the blast furnace, due to some difference in operating
conditions in northern furnaces. It has been assumed
that, on remelting once in the cupola, the gas is not
removed, but it is on repeated meltings. Just why this
should happen is not clear, because analyses of cast
irons for oxygen, hydrogen and nitrogen show no difference
between ordinary and remelted irons. The
second possibility is that some element not shown
by ordinary analysis is present in the pig and is responsible
for the trouble. Spectroscopic analyses fail
to show any difference that can be considered significant.
The third possibility is that graphite may be present
on the surface, and is not wholly removed by sandblasting.
At a sufficiently high enameling temperature
this graphite would react with the oxides of the
enamel to form carbon monoxide, which causes blisters.
By remelting, something might happen to change
the distribution of graphite, so that finally the surface
after sandblasting would be free from graphite.
In view of the possibilities sample plates were pre
pared from two northern irons melted once in the electric
furnace. The scrap produced was also remelted
and cast into sample plates. One Northern iron has
been remelted in the cupola two times and sample
plates cast. The test pieces made by the above methods
have been enameled at the bureau, with promising
results. It was found that all plates cast from the first
melting in the electric furnace blistered, but not so
badly when enameled by the dry process as when
enameled by the wet process.
Sample ,plates obtained by remelting the scrap,
both in the electric furnace and in the cupola, show no
blisters when enameled by the dry process and a decided
reduction in blistering in the wet process. It
appears that remelting the iron several times is beneficial
in reducing the blistering of the enamel. Chemical
analyses of the cupola and electric furnace melts
have been made and microscopic examination now is
in progress.