Characterization of cold lap defects in tandem arc welding
Artikel i vetenskaplig tidskrift, 2012
The objective of this investigation was to classify and characterize the small lack of fusion defects, called cold
lap, located at the weld toe. Since the defects are very small (0.01–1.5 mm) and diffi cult to detect by NDT
methods, a better understanding of the formation mechanism is required to be able to avoid their formation.
The investigation consisted of two parts. Firstly, a study was made on the type and frequency of cold laps.
Three types were identified, namely “spatter cold lap”, and “overlap cold lap” and “spatter-overlap cold lap”. No
relation between type or frequency of cold laps and the welding parameters could be established. Secondly,
the interface between spatter and the base material was investigated using optical and scanning electron
microscopy, to better understand the cold lap formation mechanism. Manganese-silicate particles were found
in the interface located in such a way that they may assist cold lap formation.
Lack of fusion