Abstract
Electron beam welding was used to make joints of SUS 405 steel. Compact tension type specimens with incomplete penetration notches were extracted from the electron beam welds. Fracture toughness tests were carried out at room temperature for the specimens in the as-welded and postweld heat-treated (685°C×2, 4 and 8 hours) conditions.
In all cases, cracks propagated in the middle of electron beam weld. Because of the natural complicated crack shape etc., a large scatter appeared in the fracture toughness, Jc. The PWHT tended to improve the fracture toughness. The effect of specimen thickness on fracture toughness Jc was also examined. The statistical model based on a Weibull distribution indicated that the fracture toughness obtained by small specimens can be used to characterize that of large specimens or real structures.
