WELDING OPERATIONS I - OD1651 - LESSON 1/TASK 2
requires increasing the angle of the electrode to 60 degrees, as
shown in figure 37, view B, on the previous page, at the middle
of the weave while simultaneously increasing the weaving speed.
As a result, the weld metal is deposited to the base metal and to
previously deposited metal instead of adhering to the butt strap.
At the end of each weave, the angle of the electrode is decreased
to 15 degrees, as shown in figure 37, view C, simultaneous with
the weaving speed, and the electrode is held momentarily adjacent
to the side wall to ensure good side wall penetration.
After
depositing the root pass, the butt strap can be removed by
breaking the tack welds which secure it to the armor plate.
A
final pass can be applied to the root of the weld after removing
the butt strap.
h. Repairing Gouges. Occasionally, a projectile will impact on
the armor plate at an angle and only gouge it without
penetrating.
To effect repairs, the gouge should be prepared
into a double V joint, as shown in figure 38, view A, on the
following page, to allow welding from both sides. Merely filling
the gouge with weld metal, as shown in figure 38, view B, is not
satisfactory, since it does not remove any subsurface cracks that
may have been caused by the shell impact.
Also, the heat zone
produced at the base of the filled-in gouge has poor ballistic
strength.
6.
Welding Face Hardened Armor Plate
a.
General.
(1) The face side of face hardened armor is extremely hard and
brittle.
Cracks on this type armor plate can be welded
satisfactorily from the soft side. These cracks can be repaired
by using 18-8 stainless steel reverse polarity heavy coated
electrodes. Special precautions, however, must be taken to avoid
distorting and excessively heating the armor plate.
Distortion
and excessive heat place stress on the base metal causing the
plate face to crack.
(2) Satisfactory methods for welding this type of armor makes
use of the butt strap and butt welding techniques, shown in
figures 39 and 40 on pages 85 and 86. The dimensions of the butt
strap depend on the thickness of the armor.
Butt strap
dimensions for armor up to one inch thick are
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