Optimization of process parameters in friction stir welding of armor-marine grade aluminium alloy using desirability approach

Abstract

Present study describes the friction stir welding (FSW) of armor-marine grade AA7039. Experimental investigation has been carried out by varying rotational speed (1325?1812 rpm), feed rate (26?43 mm min?1), and tilt angle (1.3??2?). Ultimate Tensile strength (UTS) and tensile elongation (TE) are employed as response parameters. Experiments are planned as per central composite design (CCD) of response surface methodology (RSM). Analysis of variance has been performed to develop empirical relationship between input and response parameters. The optimization has been executed by desirability analysis. The study reveals that that rotational speed and welding speed are most significant factor. It is observed that joint efficiency of 2.5% higher than parent metal at 1325 rpm rotational speed, 35 mm min?1 feed rate and 1.65? tilt angle can be achieved. Interaction effects between process parameters are found significant for UTS whereas insignificant for TE. It is evident that advancing side indicates comparatively lower value of microhardness. Fractography analysis of tensile specimen has been executed to apprehend the tensile behaviour of FSW joints.