Method for improving strength of laser stitch welding joint of copper and steel dissimilar metal

The invention relates to a method for improving the strength of a laser stitch welding joint of copper and steel dissimilar metal. The method comprises the steps: firstly, the metal surface at the welding lap-joint position is pretreated; then parallel groove textures are machined and constructed on the metal surface of the welding lap-joint position through a picosecond pulse laser to form shape-controllable, uniform and flat texture surfaces; and finally, laser stitch welding is conducted on the copper and steel dissimilar metal through a pulse green light disc laser to improve the welding strength. A laser texture machining technology and a laser welding technology are combined effectively to improve the bonding strength of the copper and steel dissimilar metal; shape-controllable, uniform and flat parallel microtextures are etched on the metal surface efficiently and quickly, other various microtextures with complex shapes can also be etched, and the machining efficiency is high; welding wires do not need