Study on generating rolling method for manufacturing cylindrical parts with external cross ribs

As the main structure of launch vehicle, cylindrical parts with reinforced ribs are mainly manufactured by milling, rolling and welding methods, which have a long manufacturing cycle and low material utilization. This paper proposes a new generating rolling method for manufacturing cylindrical parts with external cross ribs integrally. The generating rolling device is developed, the flow mechanism of cylindrical parts with external cross ribs is revealed and methods to minimize the underfill defects of ribs are proposed. Simulation and experiment results show that longitudinal rib is mainly formed by gradual material accumulation in the groove under circumferential compressive strain, and transverse rib is mainly formed by gradual material accumulation in the groove under axial compressive strain. Compared with longitudinal or transverse rib, the material flow of cross rib is more difficult due to small circumferential and axial compressive strain, resulting in the underfill phenomenon. Rib structure also affects the flow of material. When the rib sparsity is large or the height-width ratio is small, the rib is subjected to small radial tensile strain and circumferential compressive strain, resulting in low rib height and uneven rib filling. The proposed forward and reverse rolling method and billet preforming method can reduce the defects of uneven filling of longitudinal rib and underfill of cross rib.