Process for manufacturing ring-shaped member

Abstract

A method of producing a ring-shaped member is provided in which a material loss is eliminated, the process cost can be reduced, and a ring-shaped member can be easily obtained from a pipe member by a small number of steps. The method includes steps of: inwardly projectingly shaping a flange portion 1 c on an end portion of a metal-made pipe member 1 ; and cutting off the flange portion 1 c from the pipe member 1 , thereby obtaining a ring-shaped member 10.

1 . A method of producing a ring-shaped member in which a ring-shaped member is obtained from a metal-made pipe member, wherein said method includes steps of: inwardly projectingly shaping a flange portion on an end portion of said pipe member; and cutting off said flange portion from said pipe member, thereby obtaining a ring-shaped member. 
   
   
       2 . A method of producing a ring-shaped member in which a ring-shaped member is obtained from a metal-made pipe member, wherein said method includes steps of: inwardly bending a whole circumference of an end portion of said pipe member to shape a tapered truncated conical tubular portion; further inwardly bending said truncated conical tubular portion to shape a flange portion which is inwardly projected; and cutting off said flange portion from said pipe member, thereby obtaining a ring-shaped member.