Abstract
It is the slag pinhole defects that is occurred frequently within gas defects. There is 3 main factors. : (a) Fe-Mn-Si slag, (b) MnS and its slag, (c) Al of inoculant and Mg of spheroidizer. (b) can be differentiated by Mn and S. (a) and (c) is difficult to be differentiated because the slag component in defects is very similar. To differentiate (a) and (c), I have tested about slag pinhole reappearance, then analyzed by SEM and EDX. In the test of using 3 different inoculant, there were a lot of C. Si and Al were also found. Mn was increased slightly. In the test of using 3 different slag, Mn and Si were found at the same place. C was increased slightly and Al was decreased. It is showed 6 examples of SEM and EDX analysis for slag pinhole defects occurred on products. To differentiate (a), (b) and (c), each element was overlapped by analyzing of EDX phase.
