Weld metal microstructural characteristics in pulsed Nd: YAG laser welding

Experimental investigations were carried out to examine the influence of laser pulse energy, duration, and travel speed on weld dimension, microstructure and hardness during overlap laser bead on plate spot welding of low carbon steel. Effective peak power density is defined for taking into account the effect of overlapping. It was found that even with full penetration welds there can be significant variation in the microstructure and hardness of weld within a weld spot due to the very rapid solidification.