Friction stir welding (FSW) is gaining traction as a preferred technique due to its potential to reduce heat input and enhance the mechanical properties of welded joints. However, the path to commercializing FSWfor flange joints is not without challenges. Two primaryobstaclesare thecomplexityof theweldingpathand the intricate designrequirementsforthefixtures.Thesefactorscontributetothedifficulty indetermining the idealweld settings andprocess parameters,whichare critical for achieving optimal results. The current study addresses these challenges by applying FSW to flange joints using custom-engineered fixtures.Thesefixturesaremeticulouslydesignedtoholdthepipesandplates securely during the welding process. The focus of the research is on optimizingthemulti-performancecharacteristicsofFSWforAl6063flange joints through thehybridGrey-basedTaguchimethod.The integrityof the