40  Prakt. Met. Sonderband 47 (2015) 
Fig. 1: Lifting lugs of a large heavy-duty gas turbine engine 
Fig. 2: Detailed view of subject lifting lug 
2 Findings 
The subject part prepared for the weld repair that was not performed (Fig. 3) was sectioned in the 
area with the largest UT indications (Fig. 4). The microstructure of this steel casting is 
unremarkable (Fig. 5). However, several rather large macrocracks were found in the sectioning 
plane (Fig. 6). Scanning electron micrographs confirmed this. There is a moderate carbon 
segregation in the subject area that is unremarkable. The longest crack in the metallographic section 
was forced open for microfractography in the SEM (Fig. 7). A small pre-existing crack that could 
not have been caused by service loads was found. Within that area, microfractographic features of 
transgranular hot tearing were detected, as evidenced by a dendritic appearance of the fracture 
surface (Fig. 8). This is a hot cracking mechanism.