It is an underlying fact for the case of the joining process especially welding to have optimized parameters in order to achieve joints with outstanding mechanical characteristics. In the current work, aluminium 6061 pipes were welded using gas metal arc welding process with appropriate ER 4043 electrode and argon shielding gas. Optimum welding parameters (namely, current, voltage and travel speed) are investigated using analysis of variance ANOVA and grey relational analysis GRA statistical approaches. High tensile strength and low corrosion rate were set as required characteristics of quality welds. Since there are two responses and two objectives, multiple-criteria decision-making approach—GRA, and ANOVA are performed. Optimal parameters from these statistical approaches are converged to 110 A, 19 V and 3 cm/min, respectively. It is deduced from this study that the optimal parameters are convergent irrespective of the two used techniques for the investigated experimental data.