Abstract
Modeling that high stresses exist in the flange pipes of mufflers caused by the vibration of a moving vehicle or an operating machine, fatigue strengths of MIG outer, MIG inner and TIG inner peripheral side welded samples were defined through bending fatigue experiments. Factors affecting fatigue to failure, such as welding bead shapes, notch sizes and metallographic structures were identified through local stress measurements, FEM stress simulations, microscope observations and SEM-EDS composition analyses. Fatigue strengths decreased according to stress concentration factors in some cases but not in samples with different welding, and stress intensity factors were used for analyses.
