Page 118 - Quick Guide to Welding and Weld Inspection by S.E. Hughes, Clifford Matthews

A Quick Guide to Welding and Weld Inspection

Figure 7.11 Incomplete root penetration
. poor surface cleaning.

Incomplete root penetration
Incomplete root penetration (Fig. 7.11) is where both edges
of the root faces are not fused. Causes of incomplete
penetration include:
. incorrect joint preparation (narrow root gap, large root
face);
. incorrect welding parameters (current too low);
. poor welder technique (incorrect electrode tilt or slope
angles);
. magnetic arc blow;
. poor surface cleaning.
Root concavity
Root concavity (Fig. 7.12) is a groove in the root of a butt
weld, but with both edges correctly fused. It is sometimes
referred to as ‘suck back’. Causes of root concavity include:

Figure 7.12 Root concavity

102

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