Experimental study on the effects of incremental forming and friction stir welding on formability of AA5083 sheet

This article presents investigations on the effects of incremental forming and friction stir welding on the formability of AA5083 through comparison of experimentally predicted forming limit curves. Initially hemispherical dome stretching test was performed to predict forming limit curve for the parent sheet in conventional forming from plane strain to biaxial stretching strain path. Forming limit curve in case of single point incremental forming of parent sheet was also determined by conducting groove test. Formability in single incremental forming was found to be far better than that in conventional forming from the comparison of the forming limit curves for both the cases. Friction stir welded blanks were prepared by varying tool shoulder diameter, welding speed and tool rotational speed as input parameters following three levels of inputs parameters according to the central composite design matrix. Optimal welding parameters were selected based on the weld quality judged by bending angle of free bend test of the welded blanks and visual inspection. Forming limit curve for friction stir welded sheet was generated through incremental forming groove tests of the blanks made by optimal welding parameters. Formability of welded sheet was found to decrease compared to the parent sheet due to the severe plastic deformation and work hardening during the welding operation.