Influence of Filler Metals in the Control of Deleterious Phases During the Multi-pass Welding of Inconel 718 Plates

The present study reported the effect of filler metals on the microstructure and mechanical properties of pulsed current gas tungsten arc-welded Inconel 718 plates. Two different filler metals such as ERNi Cr-3 and ERNi Cr Mo-4 were employed for welding Inconel 718. The primary objective of this study is to suppress or eradicate the deleterious phase such as Laves or d(delta) which is considered to be detrimental to the weld properties. Microstructure examination corroborated the presence of unmixed zone at the HAZ for both the weldments. Tensile test trials envisaged that ERNi Cr Mo-4 weldments offered better tensile properties compared to ERNi Cr-3 weldments, whereas the impact toughness was found to be better for ERNi Cr-3 weldments. Line mapping analysis was carried out to study the elemental migration across the weldments. The structure–property relationships of the weldments were arrived at using the combined techniques of optical and scanning electron microscopy. Optical and SEM/EDAX analysis showed that there is no prominent occurrence of deleterious phases at the weld zone on employing these filler metals.