Figure 3-4 Undercut
Overlap (fig. 3-5): Examine carefully the toes of the weld where the weld width is
excessive to determine whether the weld metal is fused to the parent metal. If there is no
fusion, the weld metal will be built up slightly above the parent metal, thus presenting a
notch effect that may be undesirable. Unlike manual welding, overlap with automatic
welding is likely to be regular and thus more difficult to detect.
Overlap is a form of lack of fusion that cannot be fully assessed or measured by
Figure 3-5 Overlap
Weld flaws (fig. 3-6): Using optical aids when necessary, examine the weld and
heat-affected zone for weld flaws and if any are found check them against the acceptance
criteria. In some cases visual inspection may not be sufficient to determine the full extent of
a surface flaw (crack or porosity) and the use of other testing methods may be required
before the flaw can be assessed.
Appendix K Page 14