Effect of Pre-weld Solution Treatment on Mechanical Properties and Microstructure of Micro-Plasma Arc Welded Inconel 718

Abstract

Welding of Inconel 718 is always a challenging task due to the presence of complex alloying elements, which segregates in the interdendritic region and form various brittle intermetallic secondary phases. Hence, in the current investigation, an attempt has been made to study the effect of pre-weld solution treatment on micro-plasma arc welded Inconel 718 microstructure and corresponding mechanical properties. Two different quenching medium, i.e., water and air cooling, were considered during the solution treatment at 980 °C to control the initial grain size and mechanical properties of the base material. The results of this study showed that change in quenching medium affected the grain size, tensile strength, yield strength, ductility, and heat input during the micro-plasma welding to achieve full penetration. The full weld penetrations of solution-treated sheets were achieved with lower heat input as compared to the as-received rolled sheets. Lower heat input during welding resulted in refined solidified microstructure and lower segregation in the interdendritic region, hence improving the joint efficiency of the micro-plasma arc welded Inconel 718.