WELDING METHOD

摘要

Provided is a friction stir welding method for welding together a pair of metal members, wherein the flatness of the metal members is improved. The welding method comprises a first welding step that conducts friction stir welding by moving a welding rotation tool from the front side (side A) of metal members along the abutting section (J1) of each metal member and a second welding step that conducts friction stir welding by moving the welding rotation tool (H) from the back side (side B) of the metal members along the abutting section (J1) after the first welding step. The welding method is characterized by the fact that the input of heat to the metal members in the second welding step is less than the input of heat to the metal members in the first welding step.