음향방출실험을 이용한 압력용기 강 용접부의 재료특성평가에 관한 연구 = Study on material characteristic evaluation for the weldment of pressure vessel steel using AE experiment

다국어 초록 (Multilingual Abstract)

In this study, AE characteristics were evaluated against the multi-pass weld and PWHT specimens for the pressure vessel steel(SA-240 type 304L) using AE and bending tests. Post weld heat treatment was conducted against weld block and relationship between AE signals and plastic deformation behaviors was discussed including AE characteristics for all specimens. Cracks are mostly initiated at weld region in fields. Accordingly, it is necessary to monitor the micro-fracture procedures which are initiated at weld region for the safety and reliability of the weld structures in industry fields non-destructively. Charpy standard PWHT specimens were extracted from three regions such as the lowest, middle and highest regions of the weld block. Two kinds of specimens were prepared. one of blunt notch(2mm) depth was machined and the other of pre-crack(0.5mm) further was made to the direction of thickness under fatigue load. AE test was conducted against the weldment and PWHT specimens under the three and four point bending loads.