SA508 전자빔용접 공정 변수에 따른 전자빔편향 거동 및 민감도 분석

Electron beam welding (EBW) is a high-precision welding technique that concentrates high-energy electrons locally to achieve deep penetration with minimal heat-affected zones. This makes it especially suitable for the fabrication of key structural components in small modular reactors (SMRs), which often require single-pass welding of materials over 200 mm thick. However, the electron beam is highly sensitive to magnetic fields, and remanent or induced magnetic flux can cause beam deflection, adversely affecting weld quality. While prior studies have identified key factors such as remanent magnetism, accelerating voltage, material thickness, and thermoelectric effects (Seebeck effect), few have quantitatively assessed their combined influence through predictive modeling. In this study, multiphysics finite element model was employed to simulate the weakly coupled thermal, electrical, magnetic, and beam trajectory fields. The validated model was then used to perform sensitivity analyses on SA508 thick-section welding, focusing on the effects of process parameters. The results highlight the dominant influence of remanent magnetism and material thickness on beam deflection and underscore the importance of proper demagnetization and process design in high-integrity EBW applications.