Taguchi optimisation on effect of water environment in joining dissimilar al5083 and al6061-t6 aluminium alloy using friction stir welding.

Abstract

Water cooling has the potential to improve the mechanical qualities of weldment joints in butt welding configurations. However, the joining procedure on such a configuration faces a challenging defect-free joining issue with the standard approach. This project investigates the effect of welding conditions on the joint quality using three different tool pin profiles (cylindrical straight, cylindrical threaded and tapered cylinder) during dissimilar underwater friction stir welding of a 6 mm thick plate. An experimental method following Taguchi parametric design is carried out to optimise the technique on hardness and microstructure at the weld nugget. ANOVA is used to assess the effect of each process parameter, namely tool pin profiles, welding speed, welding speed, and hardness responses. The water environment approach lowers thermal flow by maintaining consistent temperature from tool pin profiles. The combination of ongoing process parameters and fast-cooling rate induced heat input improves the welded joint's mechanical characteristics and microstructural grain. The experiment revealed the appropriate process parameters of 900 rpm, 60 mm/min, and tapered cylinder pin profile. Consequently, water-cooling significantly contributes to welded joints' mechanical properties and microstructure at the optimal parameter level, resulting in improved strength performance.