Lack of Fusion Defect

Incomplete fusion zones between adjacent beads or layers, caused by insufficient heat input or too large bead spacing. These defects act as severe notches and reduce fatigue strength.

Physical-chemical mechanism of action

Lack of Fusion (LoF) occurs when the welding energy is insufficient to fully fuse all metal parts. This can be caused by too low temperature or too short dwell time of the electrode.

Metallurgical relevance & risks during welding

LoF leads to incompletely fused areas that act as severe notches. These can cause cracks and distortion and significantly reduce the fatigue strength of the weld.

Workshop practice & instructions

To avoid LoF, it is important to ensure sufficient temperature and a sufficient dwell time of the electrode. The travel spacing should not be too large to ensure complete fusion.

MetallurgieSchweißtechnik