Weldability of 1–6 mm thick AISI 316L steel with laser

Abstract This study examines the impact of filler wire addition on the microstructural and mechanical characteristics of laser-welded AISI 316L steel plates with varying thicknesses. Comprehensive characterization was performed through optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), elemental mapping, and X-ray diffraction (XRD). The joint strengths of the samples were assessed by tensile and microhardness tests. Fracture surface examinations after the tensile test were performed by SEM. The results revealed that the use of filler wire refined the weld microstructure, leading to narrower heat-affected zones (HAZ) and a more homogeneous distribution of austenite and δ -ferrite phases. The peak hardness value was 286 HV for wire-free laser welding and 345 HV for wire-assisted joints. Tensile strength decreased with increasing plate thickness, with the highest strength of 584.6 MPa observed in the 1-mm wire-assisted sample. Filler-assisted laser welding promoted a balanced phase distribution, minimized microstructural irregularities, enhanced joint integrity and mechanical performance.