Chapter 18 Weld Inspection and Repair
277
• Crown height is too low, Figure 18-23. A low
crown does not provide adequate reinforcement
of the weld. Repair this type of defect with
stringer beads to minimize weld shrinkage. Add
only enough new fi ller metal to build the crown
to height requirements. Do not overweld.
• Surfacing or overlay type weld height is too
low, Figure 18-24. Surfacing or overlay that
is not high enough reduces the durability
and service life of the surfaced material.
Repair this type of defect with stringer beads
to minimize dilution and distortion.
• Fillet weld size is too small, Figure 18-25. A
small fi llet weld does not provide adequate
strength in the joint. The weld is repaired by
removing the inadequate weld and rewelding
to create the proper size fi llet weld.
Regardless of the repair technique, these repairs
require close control to avoid overwelding and adding
additional stress to the original weld.
Surface Defect Repairs
Defects seen on the surface of the weld can extend
deep into the weld. For this reason, the defect must be
removed. After the defect has been removed, the area
must be reinspected before a repair can be attempted.
Common defects and factors to be considered when
repairing them are as follows:
• Longitudinal, transverse, or crater cracks,
Figure 18-26. On steel and steel alloys, use a
small grinding wheel like the one shown in
Figure 18-27 to remove cracks. Remove only the
amount of metal required to eliminate the crack.
Required
weld height
Actual
weld height
Figure 18-23. A groove weld crown with insuffi cient height.
Required
overlay height
Actual
overlay height
Figure 18-24. An overlay weld deposit with insuffi cient height.
Required
size
Actual size
Figure 18-25. Fillet weld leg length is satisfactory; however,
the weld is concave, which reduces the actual fi llet weld size.
Fillet weld
Groove weld
Crater
cracks
Crater
cracks
Transverse
cracks
Transverse
cracks
Longitudinal
cracks
Longitudinal
cracks
Figure 18-26. Types of cracks that may be found on
groove and fi llet welds.