Characterization of a manual gas tungsten arc weld overlay using Inconel 686

Inconel 686 (IN686) is positioned well for use in overlaying applications in high-temperature corrosive environments. The objective of the present study was to understand the effect of a manual gas tungsten arc-weld (GTAW) overlaying process of IN686 on its microstructure and mechanical properties. Elevated levels of dilution, or elemental mixing as a result of heat input (HI) from the GTAW process was found to be 43.60% ± 3.85% and 35.82% ± 0.93% for the high and low HI samples, respectively. The resultant composition of the overlay passes was found to correlate to their respective hardness values; the first pass in both samples were found to be significantly softer than subsequent passes, at ∼190 HV, versus an average hardness of ∼210 HV for the remainder of the passes in both high and low HI samples. Evidence of topologically close-packed phases, deleterious to overall performance, were identified, as well as process-related defects, underscoring the need for in-field defect detection methods.