Formation of solidification-induced cracks in laser-beam-welded joints on unalloyed and low-alloy structural steels

摘要

It was observed that cracks occur in the weld metal during the laser-beam welding of unalloyed and low-alloy structural steels as the welding speed increases in the case of plate thicknesses of more than 10 mm. Until now, these have been regarded as solidification cracks. However, our own laser-beam welding tests on a 13 mm thick structural steel S355N at various welding speeds and with different filler metals indicated that the cracking does not take place according to the classical mechanism of solidification cracking. Therefore, the assumptions customary until now about the hot-crack character of solidification-induced cracks should be reconsidered.