Hot tear presents as a jagged crack line through the casting. This defect indicates that the metal filled the mold, but cracked at solidification (the metal shrinks as it solidifies and tears apart due to restriction).

Note: some metals are more prone to hot tearing than others. 

 

The causes of this defect are evident in the shell, metal and other portions of the process. To cure these causes, R&R recommends taking the following actions.