SM490A 재질 용접시편 피로수명 및 스트레인 게이지?통한 균열 발생 및 진전 연구

초록

This study investigates the fatigue lives of SM490A material(base metal) specimens and weld specimens, which are made same material and weld method for the railway vehicle. These fatigue lives have a difference, the fatigue lives of weld specimen are shorter than the it of base metal. We measured the strains on the weld positions of the specimens during the fatigue test for investigation of crack initiation and crack growth. In these result, we could find the crack initiation position on weld bead and know the history of crack growth. Also we knew that the changes of the strain affect the change of surface fracture morphology and surface roughness.