This is the NGTB80N60FGWUFD (marked G80N60), an ON Semiconductor (now onsemi) IGBT — specifically a TO-247 packaged Field Stop Trench IGBT with an ultrafast soft recovery diode (the "UFD" suffix).
Key specs typically for this part:
VCES: 600V
IC: ~80A (continuous, at 25°C)
Field-stop trench technology, built-in freewheeling diode
Commonly used in welding equipment, induction heating, UPS,motor controls, inverters and other high-power switching applications