Chapter 18 Weld Inspection and Repair
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area by grinding or routing. Use extreme
care when grinding into lap joints to prevent
grinding into adjacent metal and creating
more problems. When the overlap material
has been removed, perform a penetrant
test to determine if the defect is entirely
gone. Continue removing material until the
penetrant test is satisfactory. If weld repair is
required to satisfy crown height requirements,
use low currents and suffi cient wire to match
the crown with adjoining material.
• Incomplete penetration on the root side of
butt welds. Other types of defects can also
occur on the root side of the weld, such as
concave root surface, cracks, porosity, melt-
through, etc. See Figure 18-31. Remove all of
these areas by grinding or routing. To ensure
complete removal of all defects, perform a
penetrant test before repairing the weld. Since
oxides form in this area during welding,
clean the repair area to bright metal before
rewelding. Use stringer beads and add only
enough wire to build a small crown.
Internal Defect Repairs
Internal defects, Figure 18-32, may or may not
extend to the surface and might not be found by
surface inspection. They are generally found by radio-
graphic and ultrasonic testing. Once the defect has
Cold lap
Cold lap
Incomplete fusion
Incomplete fusion
Figure 18-30. Fillet weld cold laps are usually located on
the bottom side of the weld. Butt weld cold laps can occur
on either side of the weld crown.
Concave root surface
Incomplete penetration
Porosity, cracks
Melt-through
Figure 18-31. The defects shown can occur on the root
side of the weld.
Crack
Oxide pocket
Lack of fusion
Porosity, wormhole
Figure 18-32. The defects shown can occur in the interior
of the weld.