| 摘要 |
A heat treatable aluminum base alloy is cast in a permanent mold to form an annular preform having an annular disc portion projecting inwardly from first and second annular wing portions extending axially in opposite directions from the disc portion. The preform is mounted on rotatable mandrels having peripheral surfaces spaced inwardly from the corresponding wing portions, and a forming roller presses each wing portion inwardly against the corresponding mandrel surface while the mandrels and preform are rotating to shear-form each wing portion into a substantially thinner and wider rim portion conforming to the contour of the corresponding mandrel surface. In one embodiment, the disc portion of the preform is engaged by a forming roller and a pressure roller both of which move radially inwardly while the disc portion and adjacent mandrel are rotating to shear-form the disc portion inwardly into a thinner and radially wider disc portion. In another embodiment, an outer part of the disc portion is shear-formed by a forming roller fed axially and outwardly towards the wing portions. |
