3D hardness profile mapping and geometrical defect prediction of laser-welded galvanized steel blanks using wobbling technology: an experimental investigation

This paper aims at investigating the effect of laser welding parameters on the hardness profile, using hardness mapping analyses, and welding geometry of galvanized steel plates. Hardness distribution and geometry deflection of galvanized welded thin plates are commonly applied in fields where weld quality is of utmost importance. Due to the welding process and material condition, welding galvanized steel is one of the problematic matters in welding technology. Here, the design of experiment (DOE) approach is used to study the effect of process parameters. Using a pattern matrix of micro-indentation hardness experiment, the welding defects are visualized on the hardness profile of the weld cross-section. The effect of process parameters on welding defect formation is then qualitatively analyzed. The geometrical defects of welding such as weld width and voids are then quantitatively studied based on analysis of variance (ANOVA), and predictive models of welding voids and weld seam width are developed based on the regression method. Response surface method (RSM) is then applied to define the trend of process factor interaction on the welding defects. The experimental results confirm the reliability of developed predictive models of welding defect geometry, weld width, and void area of laser-welded galvanized blanks. Graphic abstract