Investigation on Microstructural Examination of Flux Bounded TIG Weldments in Post Weld Heat Treated State

Abstract

The structural material identified for this work is 15CDV6 steel belongs to the category of High strength low alloy (HSLA) family. This research is conducted in the area of Powdered flux TIG (PFTIG) and Flux bounded TIG (FBTIG) welding with the assistance of optimum process parameters procured from Grey wolf optimization tool generated in MATLAB software. The optimum nanopowder and flux gap obtained from PFTIG and FBTIG welding are utilized for the fabrication of closed square butt joint. The microstructural characterization of FBTIG weldments is analyzed in Post weld heat treated (PWHT) condition. The microstructural examinations were conducted with the help of optical and scanning electron microscopy (SEM) to evaluate the structures in the weld zone, Heat affected zone and parent material. The presence of coarse grain structure observed in the WZ leads to the lower strength and hardness of the weldment. The presence of tempered martensite in the HAZ induces strength and toughness to the region.