Forming dependence on spin roller paths for thin-walled complex components from 2195 Al-Li alloy TWBs

The spin forming provides an approach to manufacturing large-diameter thin-walled complex curved surface components based on tailor-welded blanks produced from small 2195 Al-Li alloy plates, even scraps by friction stir welding (FSW). In this study, three spin forming schemes of single-pass, two-pass, and three-pass roller paths are designed. The corresponding experimental results indicate that the rolling of the rollers during spin forming is helpful in reducing the wall thickness inhomogeneity between weld and parent material and hence improves the surface roughness. Meanwhile, spin forming makes the welds deflect. With the increase of spinning passes, the forming height, open diameter, and the weld deflection angle of components increase. Additionally, the wall thickness difference, the surface quality, and the overall unfitability of components are all improved to some extent. However, there still exists insufficient forming height and over large open diameter due to the unfitability. Therefore, to obtain an ideal formed component, a spin forming scheme was proposed through increasing spinning passes in the ellipsoidal and cylindrical segments of the mandrel. Using this improved scheme, the forming height was increased with the maximum of 18%, the unfitability value was decreased with the maximum of 97%, the surface quality was significantly improved, and the ideal spun component was obtained.