LAP LASER WELDING METHOD FOR ALUMINUM PLATED STEEL SHEET

摘要

PROBLEM TO BE SOLVED: To provide lap laser welding for aluminum plated steel sheets by which reduction in the tensile strength of a weld zone caused by the intrusion of aluminum in a plated layer into weld metal and deterioration in its fatigue strength caused by the coarsening of ferritic grains can be prevented. SOLUTION: In this lap laser welding method for aluminum plated steel sheet, as an assist gas, a gaseous mixture containing >=50% vol.% gaseous nitrogen, and the balance one or more kinds of gases selected from gaseous argon, gaseous helium and carbon dioxide is used.