Real-time monitoring applied to optimize friction stir spot welding joint for AA1230 Al-alloys

Abstract

Abstract The uppermost strength-to-weight ratio standard has enchanted growing curiosity in virtually all areas where weight reduction is crucial. One of the recent advances in manufacturing endeavoring on achieving this intention endears is Friction Stir Spot Welding (FSSW). Welding of aluminum alloys 1xxx is problematic due to its thermo-mechanical properties. The purpose of this study is to find the optimum FSSW parameters of AA1230 Al-alloy. There are a few publications about this alloy, especially in welding applications. The experimental work was conducted by using a universal drilling machine considered an FSSW machine. Real-time monitoring is done for the tool axial load and welding temperature by using compression type load cell and infrared thermometer. Mechanical properties of the welded joint are examined using a universal tensile machine. The main parameters studied in this research are rotational speed, axial force, and dwell time which is applied as 760, 1065, 1445, and 200 rpm for rotational speed, 130, 124, 118, and 112 Kg for axial force, and 64, 52, 40, and 28 s for dwell time. They were optimized using the L16 orthogonal array and Gray relation analysis method with grey relational coefficients of ξ = 0.5. ANOVA was conducted to investigate the significant FSSW parameters. The results show that rotational speed and dwell time are the most significant parameters that affected the quality of the joining zone with a joint efficiency of 91.29%. The maximum achieved shear strength is 90.38 MPa using 2000 rpm rotational speed, 40 s dwelling time, and 124 kg axial load at a temperature of 202 °C. It appeared cavity defect at the stir zone which is affected on several specimens and lead to a reduction the shear strength to 42.12 MPa as the minimum value.