Underfill defect in welding affects not only the surface integrity but also the mechanical properties of workpiece. In this paper, the effects of the process parameters on underfill defects were investigated, and the deep penetration welding by a 10-kW fiber laser on 12-mm-thick stainless steel plates was used as the case study. The correlation of the processing parameters with the formation and elimination of underfill defects was analyzed and discussed. It was found that during the autogenous laser welding of thick plates, the direction of la...
