Abstract
The relationship between the deformation heat input in the upset stage or the upset burn-off length and joint strength was examined on the friction-welded SUS304 stainless steel joints. Joint strength was evaluated by tensile test and fatigue test. It was found that the deformation heat input in the upset stage or the upset burn-off length was correlated well with tensile strength, and a stable tensile strength was obtained when the deformation heat input in the upset stage or the upset burn-off length exceeded a certain value. In the Ono's rotary bending fatigue testing, the fatigue strength of sound joints was a little less than that of SUS304 base metal. While, in the cantilever rotary bending fatigue testing, the fatigue strength of sound joints was a little more than that of SUS304 base metal. This difference probably resulted from the fatigue fracture occurred in the softened area in the Ono's type testing and at the weld interface in the cantilever type one. Judging from the fatigue limit obtained, sound joints can be produced when the deformation heat input in the upset stage or the upset burn-off length exceeds a certain value.
