Defects Evolvement of TC4 Titanium Alloy Castings by Radiographic Inspection

In this paper, the defects evolvement of TC4 titanium alloy castings before and after hot isostatic pressing (HIP) was analyzed by radiographic inspection. The results show that most of the closed holes in castings can be eliminated by HIP and the defects will disappear on the film. A small number of inclusions and unclosed defects cannot be eliminated, and the display of the defects is nearly the same as before HIP. Few shrinkage cavity defects were partially compressed or their surface was crushed. Few large shrinkage cavity defects were deformed into linear defects, and their display on the film also changed. The structure of linear defects reduces the contrast of the images of radiographic inspection, and thus affects the detection rate of linear defects, so shrinkage cavity defects should be detected before the HIP and large size shrinkage cavities should be eliminated by repair welding to avoid the defects non-detection.