X-ray Radiography Study on Defect Analysis of Electron Beam Welded Plain C-Steel and Fe-7% Al Alloy Joints

Low C-steel to Fe-7%Al alloy dissimilar joint by electron beam welding (EBW) was carried out using oscillating beam, without oscillating beam and by increasing welding speed condition. X-ray radiography technique at sub-micron resolution was employed to study the effects of scanning parameters on the defect formation. Detection and quantification of defects within welds were subsequently carried out from radiography images by image processing, segmentation of images and pattern recognition. X-ray radiography images showed the presence of porosity, wormhole and lack of fusion-type defects in the dissimilar joints. Quantitative analysis of weld defects demonstrated that beam oscillation provides better quality weld by decreasing approximately 58% porosity compared to its non-oscillating counterpart and 73% compared to higher welding speed. Wormhole and lack of fusion defects were observed at other two conditions, which did not observe in welds produced by beam oscillation.