Research on a new counter-roller active spinning process for forming Al alloy thin-walled cylinders

This study proposes a novel counter-roller active spinning process that combines the characteristics of rolling and power spinning to solve the high-quality manufacturing problem of large-diameter thin-walled cylinders for aerospace applications. The material in the forming area during counter-roller active spinning is in a complete plane strain state and avoids the circumferential deflection of the cylinder. The counter-roller active spinning tests for the 2219-O aluminum alloy cylinder blank reveal that the inner and outer materials of the workpiece flow axially, and the maximum circumferential deflection is only 1.37% of the axial dimension. When the thinning ratio reaches 75%, the radius deviation, roundness error, and wall thickness difference of the stable part of the cylinder workpiece are 0.51, 0.56, and 0.005 mm, respectively. As the thinning ratio increases, the grain refinement becomes increasingly obvious, the microstructure of the material becomes parallel, distributed, and fibrous, and the cylinder strength gradually increases. The axial ultimate tensile strength and yield strength reach 326.3 and 249.9 MPa, which are 226.67% and 58.78% higher than those of the blank, respectively. The hardness values of the inner and outer surfaces of the cylinder are consistent and symmetrically distributed along the neutral layer of the wall thickness. The difference between the surface hardness and neutral layer hardness of the material gradually decreases with an increase in the thinning ratio. The enhancement of mechanical properties is mainly due to the combined effects of improved material deformation uniformity, grain refinement, and work hardening.