Numerical analysis of residual stress and deformation in friction stir welding of large 2219 aluminum alloy cone components

This study investigates the impact of weld depth (8 mm vs. 12 mm) on the thermal, mechanical, and displacement behaviors in Friction Stir Welding (FSW) of large 2219 aluminum alloy cone components. Numerical simulations reveal that both weld depths ensure joint integrity, yet they exhibit distinct characteristics in temperature distribution, residual stress, strain, and displacement. The 12-mm weld depth results in a higher peak temperature and an increase in residual stress (93.6 MPa) compared to the 8-mm weld depth (61.8 MPa). The 12-mm weld depth also results in a larger peak displacement field, with a maximum displacement of 0.429 mm compared to 0.442 mm for the 8-mm weld depth, due to amplified thermal expansion and contraction, a wider plastic deformation zone, and stronger structural constraints. The temperature distribution is more extensive in deeper welds, with a significantly higher heat-affected zone (HAZ), primarily due to increased heat input. Moreover, the 12-mm weld depth leads to a larger plastic deformation zone, which accumulates more residual stress. Variations in welding start position and direction have minimal effects on stress and strain distributions, confirming that welding depth is the primary factor influencing the thermal and mechanical behavior of the welded joint.