Effect of Nd–YAG laser pulse shape on welding characteristics of STS 310S stainless steel

This paper describes a study of the effects of pulse shaping on weld dimensions and weld discontinuities in continuous seam welds of STS 310S stainless steel using a Nd–YAG laser. Laser weldability tests for STS 310S and Inconel 600 were also carried out. Pulse shapes evaluated in this experiment were of the type generally applied in YAG laser materials processing, the ramped up type (three steps), and the ramped down type (three steps). The pulse energy was constant regardless of type of pulse shape. Penetration of laser welds increased as pulse width and peak power increased. The ramped up type pulse was the most effective for deep penetration. With regard to the weld discontinuities (porosity and hot cracking), the general type pulse gave poorest results and the ramped down type pulse gave the best.