Study on Near-Net Forming Technology for Stepped Shaft by Cross-Wedge Rolling Based on Variable Cone Angle Billets

Area of Science:

• Materials Science and Engineering
• Manufacturing Processes
• Metal Forming

Background:

• Stepped shafts are critical components in various mechanical systems.
• End concavities are a common defect in stepped shaft manufacturing via cross-wedge rolling (CWR).
• Understanding metal flow and defect formation is crucial for process optimization.

Purpose of the Study:

• To establish plastic flow kinetic theories for metal deformation during CWR of stepped shafts.
• To investigate the forming mechanism of end concavities.
• To determine the influence of variable cone angle billet parameters on end concavity formation.

Main Methods:

• Utilized DEFORM-3D finite element software for simulation.
• Employed the point tracing method to analyze metal flow.
• Conducted single-factor tests and rolling experiments with variable cone angle billets.

Main Results:

• End concavities form in stages during CWR, influenced by wave mode and billet shape parameters.
• Cone angle (α) and first cone section length (n) significantly impact concavity depth, with α having the most pronounced effect.
• Total cone section length (m) has a diminishing influence; optimal parameters reduce concavity depth.

Conclusions:

• Finite element analysis and experimental results show high consistency (error < 5%).
• Provides a theoretical basis for controlling end concavities in CWR.
• Enables rational design of variable cone angle billets to improve stepped shaft end quality and achieve near-net forming.