한국주조공학회

Most investment castings contain some porosities and microcavities. In this study, we investigated the elimination trends of various internal defects in IN738LC investment castings for industrial gas turbine blade by hot isostatic pressing. The results showed that cylindrical defects which are under size are mostly eliminated and aspect ratio of defects is more sensitive factor than their cross section shape in removing these defects. Increasing hot isostatic pressure and holding time doesn't affect the elimination trend of cylindrical defects over size because first step(plastic deformation) of HIP densification doesn't occur under these HIPping conditions.