| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of a recess in a weld zone by abutting the end of a second member on the end of a first member excluding a part projecting from its face in the thickness direction, inserting a rotary body, which has a small diameter part at the tip end of a large diameter part, in the manner that the boundary between the large and small diameter parts is located between the extension of the face and the apex of the projection, and revolvingly moving the rotary body along the abutted part for welding. SOLUTION: The small diameter part 72 of the two rotary bodies 70, 70 is inserted revolvingly into the weld zone of hollow sections 50, 60 and moved simultaneously along the longitudinal direction of the weld zone. The boundary 73 between the large and small diameter parts 71, 72 of the rotary body 70 is located between the extension of the outside face of the plates 51, 61 excluding the thick part 56, 66 and the apex of the thick part 56, 66. The small diameter part 72 is in the abutted part. Even if a gap exists between the thick part 56, 66 and the end part 56a, 66a, the base material of the thick part 56, 66, which is fluidized by friction stirring welding, is pushed into the gap, preventing defects from generating in the weld zone. Its upper face is machined by a grinder, and made flush with the upper surface of the plates 51, 61. |
