Unveiling Impact of Electron Beam Optics on Weld Attributes in EN30B Steel

The influence of electron optics in terms of beam oscillation (BO) has been studied on weld quality of several steels and reported to develop cosmetic weld with smooth surface and enhanced weld properties. However, effect of electron BO on the weld quality of medium carbon low alloy steel, especially EN30B, has not reported well and investigated in this study. By manipulating magnetic lens in-line with electron beam, the diameter of oscillating beam (OD) and its effect on weld quality has been studied. The OD was changed between 0.5 mm and 2 mm. Numerous tests, including X-ray diffraction, scanning electron microscopy (SEM), Electron Backscattered Diffraction (EBSD), hardness, wear, and tensile, were used to characterize the weld quality. Welds with BO significantly lowered the heat input rate than welds without oscillation. In presence of BO, retained austenite (RA) in the weld increased and it became least in welds made without BO. Tensile residual stress was found in the fusion zone (FZ) and it was higher with BO, especially with higher OD. In contrast to columnar grains predominantly found in welds made without BO, significant equiaxed grains were identified in welds made with BO. Nonmetallic inclusions (NMIs) in the weld became finer and less by use of BO. Introducing BO enhanced the hardness and reduced wear rate of weld, particularly at greater beam OD. Although weld strength was diminished in comparison to the base metal (BM), BO increased the weld's ductility and strength.   Received: 26 October 2023 | Revised: 15 January  2024 | Accepted: 18 January  2024   Conflicts of Interest The authors declare that they have no conflicts of interest to this work.   Data Availability Statement Data sharing is not applicable to this article as no new data were created or analyzed in this study.