Study on the abnormal image appeared in radiographs of welds, 2

In the first report, the cause of the abnormal images appearing at times in the X-ray radiographs of the welded parts of austenitic stainless steel was originated from the diffraction phenomena when X-ray passed through the welded parts. Then, the abnormal images are not the phenomena peculiar to austenitic stainless steel, and when welded parts are anisotropic, and crystal grains are coarse, they seem to appear in the radiographs of other metals. In the welding of pure metals, the abnormal images may be observed very clearly. In this study, cupro-nickel (90 Cu 10 Ni), pure aluminum and aluminum-magnesium alloy were selected as the metals of face centered cubic lattice, and ferritic stainless steel (SUS 405) as a metal of body centered cubic lattice. The state of abnormal images appearing in the radiographs of their welded parts and the relation between the metal structures and X-ray diffraction were examined. Thus, the cause of abnormal image appearance and the factors affecting the appearance were clarified. Though the images of brush, line, spot and granule shapes were observed, there was not any defect in metals. The abnormal images appear when X-ray passes through welded parts by the relation of solidified structure and X-ray diffraction. (Kako, I.)