CoHErrelation between weldability and improvement in properties is a key issue in materials science research. The objective of this work is to optimize the process parameters viz., aging temperature, aging time, solutionizing time, to enhance the hardness of Al6061 alloy. Hence, the present paper deals with hardness study of Tungsten Inert Gas welded 6061 aluminium alloy after age hardening under three different aging temperatures, aging time and solutionizing time using Taguchi’s L₉ Orthogonal array. Finally, a second order model has been generated for hardness using Response Surface Methodology with 20 runs for full design. The predicted and experimental results are in good agreement.