Multi-response optimization of process parameters of GMA welding of dissimilar AA 6061-T6 and AA 5083-O aluminium alloy for optimal mechanical properties

Abstract

The sufficient tensile strength and hardness are important parameters to decide soundness of the joint; that is dependent on the welding parameters. The influence of welding parameters of gas metal arc (GMA) welding on mechanical properties (tensile strength and hardness) of the joint of dissimilar aluminium alloys 6061-T6 and 5083-O has been investigated. A mathematical model is developed to predict tensile strength and weld hardness of the joint. Response surface methodology is applied in the study. Three factors (welding current, welding voltage and gas flow rate), three levels and rotatable central composite design with full replications technique was used. The results indicate that welding current has the greater impact on tensile strength and weld hardness of the joint; followed by welding voltage and gas flow rate. Tensile strength and weld hardness are increasing with increase in welding current. Welding voltage and gas flow rate have negative effect on tensile strength and weld hardness. The optimum welding parameters is investigated to maximize tensile strength and hardness of the joint under the constraint of used GMA welding machine. A welding current of 182 Amp, welding voltage of 20 V and Ar gas flow rate of 17 lit/min are found optimum welding process parameters.