This work investigates the influence of filler metal composition on the corrosion resistance and mechanical properties of alloy 690 weldments. Alloy 690 (61 wt.% Ni, 30 wt.% Cr) was used as the base metal. Inconel I-52 (61 wt.% Ni, 29 wt.% Cr) and I-82 (73 wt.% Ni, 20 wt.% Cr) rods were used as filler metals. Manual gas tungsten arc welding was performed using four weld passes in three layers for a single-V groove butt weld. The subgrain structure near the centerline of the fusion zone middle layer was cellular and columnar dendritic in the I-52 weld, but was dominantly equiaxed dendritic in the I-82 weld. Both had white particles dispersed in the fusion zone. The I-82 weld had more white particles and a denser subgrain structure. Compositional analysis showed the I-52 weld's interdendritic region had higher Al, Si, Ti, N content than the dendritic core. The I-82 weld's interdendritic region had higher Al, Si, and Nb content than the dendritic core. The Ni and Cr content of interdendritic white particles of the I-52 and I-82 welds decreased to 38, 23 wt.% and 11, 9 wt.%, respectively, much lower than the base and filler metals. This situation causes high corrosion at the white particle sites during Modified Huey testing. Thus, the I-52 weld had better corrosive resistance than the I-82 weld. However, I-82's superior weld joint strength is attributed to its finer fusion zones subgrain structure and giving it higher tensile strength and elongation.
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