Method of producing ring-shaped metal parts

摘要

A method of producing a plurality of identical ring-shaped metal parts from a single blank in the form of solid rod without forming any hole in the blank and without cross-sectionally cutting the blank. The outer periphery of the blank corresponds to the inner periphery of the metal parts to be produced. First the blank is longitudinally compressed such that an end portion of the blank undergoes upsetting and provides a laterally expanded portion having a side periphery corresponding to the outer periphery of the metal parts and a length corresonding to the thickness of the metal parts. Then the laterally expanded portion is subjected to shearing along a plane defining the outer periphery of the blank to part its peripheral region as one of the ring-shaped metal parts. The blank remains in the solid rod form, though somewhat shortened, and therefore can be used to produce additional metal parts by repeating the same procedure until it becomes very short. The upsetting step and the shearing step can be performed in the same machine by using a set of opposingly arranged dies and coaxially arranged punches. Ring-like metal parts noncircular in their outer and inner peripheries can also be produced by the same method.