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 TM 55-1905-221-14-3
6-16
PROPELLER, PROPELLER SHAFT, AND STUFFING BOX (Continued)
LOCATION/ITEM
ACTION
REMARKS
REPAIR (Cont)
between 600 and 800 F
F
(316 and 427 ), will
C
C
preclude the accumulation of
harmful stresses. Hot-flow
welds and large gas welds
are automatically preheated
and slowly cooled, and
stress relief can be safely
omitted after welding. Arc
welds and small gas welds
should be preheated with a
torch or other suitable
means and then cooled
slowly. If it is considered
more desirable to stress
relief after welding,
the following procedure is
recommended. Heat slowly to
750 (399 ) and hold at
F
C
this temperature for at
least 1 hour per inch of
thickness of metal in the
welded area; cool slowly,
approximately 2 (1 ), per
F
C
minute, until metal is below
250 (121 ), after which
F
C
air-cooling is permissible.
During all preheating,
welding, or stress relieving,
the propeller should be well
supported in order to avoid
sagging and distortion.
Repairs, particularly to
heavier sections of the
propeller, should be
performed with care in order
to avoid thermal cracks or
tears due to shrinkage
stresses which can be
imposed on the base metal.
6-183
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