2003 Volume 21 Issue 1 Pages 126-132
It is difficult to match joint phases at the particular position of a rotation side a fixed side using a conventional friction welding machine, because the rotating spindle does not control the exact stop position. A development of positioning controlled friction welding meets to be solved such difficulties as stop at the specified position during duration of braking. This positioning control friction welding was achieved by installing servo motor positioning system.
A phenomenon of positioning control was examined by the friction welding of carbon steel. The positioning control was satisfactory performed with sufficient accuracy. The undershoot and the overshoot behaviors were observed to the specified position during operation. Heavy metal flow was observed in the vicinity of weld interface in case of positioning control. Characteristic flash was formed by the heavy metal flow during positioning control. The metal flow became heavy with the stopping period increase. The direction of metal flow was circumferential, when positioning control friction welding. The rotative direction of metal flow was changed due to the overshoot or the undershoot behavior. When stopping period was optimized, metal flow became minimized. In this examination, 0.3 s was optimum stopping period.
The fracture of tensile test specimens occurred at the base metal, when the position was controlled. However, tensile strength of positioning controlled joints was equal to the strength of base metal. The positioning control did not affect on the tensile strength of welded joints.
