Insights in Strain and Stress States of Conical Shapes Flow Forming

Flow forming is an incremental forming process frequently used in manufacturing axi-symmetric parts that require high mechanical properties and fatigue resistance for dynamic applications, such as automotive and aerospace, or large-size components whose deformation in one step would require excessive loads. Nevertheless, the process design still remains challenging since the strain and stress states of the locally-deformed material are not clearly understood. To fill this gap, the paper focuses on the numerical modelling of forward flow forming, when it is applied to freeform-section profiles. The reference process is the flow forming of an aluminium alloy automotive wheel carried out in hot conditions. Results in terms of strains and stresses applied to the material by the rollers are presented, showing that relevant hydrostatic pressure conditions may be general with beneficial effects on the material formability.