Repair welding of wrought superalloys: Alloy 718, Allvac 718Plus and Waspaloy

The ability to weld repair three precipitation hardening superalloys, i.e. Alloy 718, Allvac 718Plus and Waspaloy, with gas tungsten arc welding, is compared in this study. Four different solution heat treatment conditions for each material were examined: Alloy 718 and Allvac 718Plus heat treated at 954 degrees C-1 h, 982 degrees C-1 h, 954 degrees C-15 h and 1020 degrees C-1 h and Waspaloy for 4 h at 996 degrees C, 1010 degrees C, 1040 degrees C and at 1080 degrees C. By metallography, the total number of cracks was evaluated in both the heat affected zone and the fusion zone, which made it possible to consistently rate the repair weldability of these three materials. Alloy 718 was significantly the best one, with Allvac 718Plus slightly better than Waspaloy. As expected, the solution heat treatment conditions only affected the heat affected zone cracking behaviour.