Achieving uniform microstructure and properties in large-sized seamless thin-walled cylindrical components with high-ribs using novel forward needle penetration extrusion process

• A novel forward needle penetration extrusion process enables precision manufacturing of large-sized seamless thin-walled cylindrical components with high-ribs, achieving superior material flow uniformity (SDV=0.478). • Optimal process parameters (billet 465°C, die 460°C, container 420°C, speed 1.5 mm/s) yield exceptional microstructural homogeneity compared to conventional porthole extrusion. • The process induces significant fragmentation of coarse secondary-phase particles and fibrous grain structures, with GDRX and DDRX as dominant recrystallization mechanisms. • Mechanical property variations across regions are within 7%, with rib head region exhibiting highest tensile strength (360 MPa) and yield strength (215 MPa), and all regions showing elongation >22%.