| 摘要 |
A cross-rolling mill comprising a plurality of workpiece engaging rolls (10, 11) defining between them a roll aperture through which a workpiece (23) passes during rolling, and a workpiece engaging tool (20) associated with said rolls, the mill being characterized by said tool (20) being a composite internal tool associated with said roll aperture and including a tapering piercing portion (21) and a substantially cylindrical elongating portion (22), means for moving said tool along the axis of the mill relative to the rolls to accommodate a piercing operation in which the piercing portion (21) of the tool (20) coacts with the rolls (10, 11) and an elongating operation in which the elongating portion (22) of the tool (22) coacts with the rolls (10, 11), and, means for reversing the direction in which the workpiece passes in use through said roll aperture so that piercing can take place in a first pass in one direction and elongation can take place in a second pass in the opposite direction, the profile of the rolls being such as to accommodate both piercing and elongating operations. Also disclosed are methods of operation and a mill employing opposed cone rolls. <IMAGE> |
