구조용 강 SS400의 용접부 잔류응력이 파괴인성에 미치는 영향

Effects of a Residual Stress near the Weld Zone of a Structural Steel SS400 on Fracture Toughness

In this paper, we investigate the effects of a residual stress on fracture toughness near the weld zone of a structural steel SS400. The critical ？？-integrals, the fracture toughness of the elastic-plastic fracture mechanics are for the welded and notched CT specimens of SS400 with tensile residual stress, with compressive residual stress, and without residual stress. The welded CT specimen is fabricated by CO2 laser welding machine. The direct current potential method is used in the measurement of the fracture toughness. It is concluded that when the tensile residual stress ahead of the crack front is distributed, the fracture toughness is dropped.