| abstract |
Metal materials (100, 102) of such as Fe are abutted against each other at a joining portion (104), and the probe (12) of a rotating tool (11) is inserted into the joining portion (104). When the rotating tool (11) is moved in the longitudinal direction of the joining portion (104) while being rotated, the metal structure of the joining portion (104) is agitated to allow the metal materials (100, 102) to join with each other. When the rotating tool (11) is moved while being rotated, liquid CO2 is supplied to the joining portion (104) and the rotating tool (11). Nozzles (16, 18) discharge liquid CO2 from the rear in the moving direction of the rotating tool (11) by properly opening/closing solenoid valves (20, 22). Supplying liquid CO2 to the joining portion (104) and the rotating tool (11) can reduce abrasion of the rotating tool (11), and can improve the joint strength of the joining portion (104). |