Strategy of Suppressing the Solidification Cracking Susceptibility of 247LC Superalloy Weld Metals using Commercial Ni-Based Fillers

Abstract

The solidification cracking susceptibility of 247LC superalloy dissimilar welds with ERNiCrCoMo-1, ERNiCrMo3, and ERNiFeCr-2 commercial fillers was quantitatively evaluated using Varestraint testing for the sound weld geometries of gas turbine blades. We confirmed that the solidification brittle temperature range (BTR) of the 247LC/ ERNiCrMo-3 dissimilar weld was 217 K, which was measured using a thermo-vision camera during the Varestraint testing, and the BTR increased to 260, and 485 K with the ERNiCrCoMo-1 and ERNiFeCr-2 fillers, respectively, Based on theoretical calculations of the weld solidification path (i.e., using Scheil’s model; performed via the software Thermo-Calc) for each dissimilar weld, the variation in the BTR can be considered to be highly dependent on the solid-liquid coexistence temperature range of the dissimilar welds, and it is also correlated with the low-temperature formation of topologically closed packed phases during the terminal stage. Based on the experimental and theoretical results, the commercial Ni-based filler ERNiCrMo-3 is expected to be an effective welding material for 247LC dissimilar welding and the successful manufacturing of high-soundness blades.