摘要 |
A disc-like or annular workpiece within a set of closed dies undergoes lateral flow in a first direction (e.g., radially outward or inward, depending upon the geometry of the die cavity) as the upper die is forced against the lower, with the workpiece being now restrained from flowing in other directions. Toward the end of forging, when the metal offers a rapid increase in resistance to flowing, the workpiece is set free of the restraint from flowing in a second direction, generally opposite to the first direction, as by creating a bore centrally therein or by cutting off its peripheral portion. Then, upon resumption of forging, the workpiece flows in both first and second directions, completing the desired flow in the first direction with no greater forging force than before. |