Patent ID: 7845544

Claim:
A friction stir welding method for friction stirring and welding a material by using a rotating tool having a shoulder and a pin at a front end portion of a shaft portion thereof and ejecting a cooling agent from a cooling nozzle to the tool to be cooled thereby, the friction stir welding method comprising: ejecting the cooling agent from the cooling nozzle toward an outer surface of a middle shaft portion, said middle shaft portion being in a middle portion of the shaft in an axial direction of the rotating tool shaft portion, said cooling agent being ejected at a position and in a direction, relative to the rotating tool shaft portion, so as to contact and flow over the outer surface of the tool shaft portion at a location spaced from the shoulder and the pin so as to cool the middle shaft portion of the tool, wherein the nozzle is spaced a distance from the tool and oriented relative to the tool such that a majority of the cooling agent travels in a vertical direction away from the pin upon exiting a tip end of the nozzle and thereby cools the middle portion of the shaft portion of the tool.