冷間後方カップ押出し鍛造におけるねじり振動付加による軸方向押出し荷重の低減

―ねじりモーション付加鍛造加工法の開発 第1報―

抄録

To reduce axial load in cold backward extrusion, torsional oscillation with a maximum frequency of 1.5 Hz around the extrusion axis was superposed with axial deformation. A cylindrical aluminum workpiece was simultaneously extruded in the axial direction and twisted in the circumferential direction between extrusion and knockout punches with a maximum axial speed of 0.1 mm/s, an alternating amplitude of 5°, and a maximum angular speed of 5 rpm at room temperature. The relationship between the torsional oscillation conditions and the axial load was investigated in backward extrusion with reductions in cross-sectional area of 0.17-0.69. The maximum reduction in axial load was obtained with approximately 20% in backward extrusion with a reduction in cross-sectional area of 0.51 under rotation/extrusion speeds higher than 60°/mm. The influence of the friction condition, the work-hardening characteristic of the workpiece, and the reduction in cross-sectional area on the reduction in axial load was discussed using the results of finite element simulation.