CO_2 laser-weldability of galvanized steel sheets

The CO_2 laser butt welding of galvanized steel sheets cut by the CO_2 laser was investigated for automotive manufacturing application. 4 kW was used to weld the galvanized steel sheets of different thickness, and the maximum speed reaches 0.1 m/s. The laser welded seams whose butt sides were cut by laser or mill was compared, and the hardness distribution was measured. The width of the laser welded seam was in the range of 0.5～1.0 mm,and the maximum hardnes of the welded seam overpass the matrix hardness 1～1.5 times. The laser welding produced similar qualities for the steel sheets cut by laser or mill.