| 摘要 |
PROBLEM TO BE SOLVED: To improve durability of a joining tool, to reduce joining time of a workpiece by high-speed revolution of the joining tool, and to increase joining strength of a weld zone. SOLUTION: A coating film 50 composed of aluminum nitride is formed on the surface of the joining tool 4. The joining tool 4 is pressed against the workpiece 2 while being rotated at high speed, and stirringly buried in a part softened by frictional heat, thereby solid phase-welding the weld zone 3 of the workpiece 2. The coating film 50 is formed in a region at least in contact with the workpiece 2 and has wear and abrasion resistance against the workpiece 2. The coating film prevents wear of the joining tool 4 and diffusion into the workpiece caused by chemical reaction between the workpiece 2 and the joining tool 4, and attains a long life of the joining tool 4. In addition, the coating film helps increase in the revolving speed of the joining tool 4, resulting in reduction in the welding time of the workpiece 2, increase in the generation of frictional heat in contact with the workpiece 2, and expansion of stirring region in the workpiece 2, thereby preventing the strength of the weld zone 3 from degrading. Further, the coating film prevents the component elements of the joining tool from mixing into the workpiece through diffusion, which is harmful to mechanical properties such as strength of a joint. COPYRIGHT: (C)2008,JPO&INPIT |
