Evaluation of Tensile Strength and Fatigue Strength of SUS304 Stainless Steel Friction Welded Joints

摘要

Friction welding of SUS304 stainless steel was carried out in order tornexamine the relationship between joint strength and deformation heatrninput in the upset stage or upset burn-off length. Joint strength wasrnevaluated by tensile and fatigue testings. It was found that therndeformation heat input in the upset stage or the upset burn-off lengthrncorrelated well with joint strength. That is;;when the deformation heatrninput in the upset stage and upset burn-off length exceed 120 J/s andrn1.0 mm respectively;;a stable tensile strength was obtained. The tensilernstrength of sound joints was lower than that of SUS304 base material,rnbecause the heat affected zone of joints was softened by the frictionrnheat and the fracture of sound joints occurred in this softened area.rnMeanwhile;;the fatigue strength of sound joints was higher than that ofrnSUS304 base material. This is probably because the material near thernweld interface was hardened due to the work hardening. Evaluating thernfatigue limit obtained in the fatigue test revealed that when therndeformation heat input in the upset stage and the upset burn-off lengthrnexceed a certain value;;sound joints can be produced as well as goodrntensile strength.