Page 120 - Quick Guide to Welding and Weld Inspection by S.E. Hughes, Clifford Matthews

A Quick Guide to Welding and Weld Inspection

Figure 7.14 Overlap

. incorrect welding technique;
. current too low.

Underfill
Underfill (Fig. 7.15) is the term given to a joint that has not
been completely filled to the parent metal surface but the
edges of the joint have been fused. Causes of underfill
include:
. too small an electrode being used;
. too few weld runs;
. poor welder technique.
Undercut
Undercut (Fig. 7.16) is an unfilled groove left at the toe of the
weld following melting of the parent material. It can also be
found in previously deposited weld metal. The problem with
undercut is that it causes a reduction in material thickness
and is a stress concentration from which failures such as

Figure 7.15 Underfill

104

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Data Standards Ltd, Frome, Somerset – 17/9/200907QG Welding chap7.3d Page 104 of 107