Pierce

In ring rolling, the process of providing a through hole in the center of an upset forging(1) A forging made by upsetting an appropriate length of bar, billet or bloom. (2) Working metal to increase the cross-sectional area of a portion or all of the stock. (3) A forging formed by heading or gathering the material by pressure upon hot or cold metal between dies operated in a horizontal plane.... More using a tapered or cylindrical punch. See DriftingIn forging, the operation of forming or enlarging a hole by use of a tapered punch..