Formability of high-pressure thin-walled cylindrical parts by counter-roller spinning process: Considering different roller rotation modes
摘要
Counter-roller spinning (CRS) has proven to be a viable technique for manufacturing large-diameter, high-pressure, thin-walled cylindrical parts. However, the formability of CRS is significantly influenced by roller rotation modes, with low accuracy limiting its large-scale application. The traditional passive CRS (PCRS) and the full active CRS (FACRS) process are systematically compared to evaluate their respective effects on formability. Modeling and experiments indicate that the FACRS intensifies the material’s stress and flow in circumferential direction, promoting more uniform material flow. Notably, the radial strain difference is only 5.56% of that in PCRS, effectively eliminating the radial strain gradient and yielding a more consistent axial flow distribution. Additionally, FACRS reduces stress triaxiality η, leading to a more stable surface mechanical state. The rollers’ active pre-rotation alleviates initial impulsive friction, significantly reducing initial torque. FACRS also improves linear accuracy by 11.81%, while enhancing tensile and bending strength, rigidity, and isotropy. Post-spinning, grain refinement and ductile void fracture behavior are observed. In contrast, the PCRS excels in certain localized mechanical properties, self-adjusting torque reduction effect during stable spinning, and superior ovality. By elucidating deformation mechanisms of both modes, these results establish a theoretical framework for synergistic process development, providing fundamental insights to combine FACRS's homogenization benefits with PCRS's adaptive characteristics for next-generation precision forming of large thin-walled components.