Although the possibility of orbital rotaryforming of tube-end has been reported for anoutward-flange having large value of flaring ratio, thepossibility has not been illuminated previously for aninward-flange having large value of nosing ratio. Inorder to clarify the possibility of the inward-flanging,an orbital rotary forming process in which aninward-flanged shell is formed from a tube by means ofrotary conical nosing and subsequent orbital rotaryflanging has been proposed. Hard aluminum tubes areformed to inward-flanged shells, and the deformationbehavior is examined. It is found that the inward-flange having large value of nosing ratio can be formedfrom a tube by means of the proposed process. Theproposed method with a retainer ring which preventsbuckling is found to be effective in improving thenosing limit. The inward-flanging limit of the proposedmethod is superior to those of conventional inward-flanging methods, such as spinning and press forming.Furthermore, the proposed method with a retainer ringseems to have a significant effect in making the flange thickness more uniform.
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