Characterization of the laser dimpling process on galvanized steels for automotive applications

The laser welding of zinc coated steels in lap joint configuration poses serious problems, due to the difference between the melting temperature of the steel (1500°C) and the vaporizing temperature of the zinc (906°C). The laser dimpling technique was studied. This solution is used to create protrusions on the surface of one of the two parts that work as spacers, allowing the escape of the zinc vapors from the joint, avoiding weld defects. The influence of the laser parameters on the height of the protrusion was studied and regression models were drawn. In the last part of the dissertation the hardness of the dimples was measured and a prediction of the tensile strength was made