Active shovel spinning process: Plastic deformation behavior, microstructure, and properties

•Proposing an active shovel spinning process for forming a thin disc with a cylinder.•Developing the multi-objective optimization influenced by multi-process parameters.•Clarify the plastic deformation mechanism in different zones of the spun parts.•Analyzing the influence mechanism of grain variation on mechanical properties.•The new spinning process improves the mechanical performance of spun parts. In response to the challenges of traditional casting and welding processes for thin disc with cylinder, characterized by excessive weight, complex procedures, and variable seam quality, a novel active shovel spinning (ASS) process is proposed. This technique utilizes a spinning roller to lift the sheet metal radially, gradually forming the cylindrical wall into a monolithic structure. A finite element (FE) analysis model for the ASS of SPHE material is established, with the optimization goals set as the outer diameter ellipticityO¯r, the precision of the outer generatrixL¯I, and the maximum forming force Fmax of the spinning roller. Using extreme difference analysis and the Grey Relational Analysis (GRA), multi-objective optimization under various conditions of rotational speed ratio η, feed rate v, and friction coefficient f is conducted to identify the optimal combination of process parameters as η=1.6, v = 2, and f = 0.15. The plastic flow behavior under these parameters is analyzed, and experimental studies are conducted. The findings reveal extensive metal flow in radial, axial, and circumferential directions. The bulging of the cylinder primarily relies on the deformation of the metal at the upper ends of the inner and outer sides, with greater stress and strain on the outer wall than the inner. The disparity between the deformed and undeformed areas is mainly reflected in the position and diameter of the stress Mohr's circle and the size of the strain Mohr's circle diameter. Due to the increased aspect ratio, refinement, and uniformity of the grains, the ultimate tensile strength σUTSi in all directions within the forming area has significantly improved, with a 48 % increase in the reduced thickness area σUTS1CD and a 31 % increase in the σUTS2CD. These results enhance the understanding of the forming mechanism in the ASS process, thereby providing crucial guidance for optimizing the quality of the formed components.