Investigation of Microstructure and Mechanical Properties of Al Alloys Lap Joints by Friction Stir Welding

An experimental investigation on effect of friction stir lap welding (FSLW) process parameters on mechanical and microstructure of AA6082-O welds is presented. Three process parameters namely tool rotational speed (1000,1400 & 2000 rpm), tool shoulder diameter (18, 20 & 22 mm) and tool traverse speed (28, 56 & 80 mm/min) are considered. Experiments are planned as per L9 Taguchi array. Data are analyzed in terms of S/N ratio and Analysis of Variance (ANOVA). Tensile shear strength is observed in the range of 11.79 MPa to 29.23 MPa. It is observed that tool diameter and tool rotational speed are most significant factors affecting tensile shear strength. Optimum levels of process parameters (28 mm/min tool traverse speed, 18 mm tool diameter and 1400 rpm tool rotational speed) is decided based on analysis of experimental data. Using optimum process parameters for friction stir lap welding of Al alloys improved quality of welded joints can be made. Use of optimized parameters will improve the performance of the products in terms of durability and load carrying capacity.