| 摘要 |
<p>The disclosure is directed to improvements in piercing and reeling mills, to facilitate the changing of mandrel plugs and mill shoes. In piercing and reeling operations, mandrel plugs are supported at the ends of elongated mandrel bars, and workpieces are driven over the mandrel plugs while being rotated, to effect piercing and enlarging, in the case of piercing mills, and to achieve roundness, in the case of reeling mills. In each case, after processing a finite length of tubing, and while the workpiece remains on the mandrel, the mandrel is retracted, first stripping off the just-used mandrel plug, and then withdrawing the mandrel from the processed workpiece. A multi-position magazine is provided for retaining a circulating supply of mandrel plugs such that, after each operation, the used mandrel plug may be returned to the magazine for cooling, and a new plug may be brought quickly into working position ready for the next operation. The arrangement of the invention provides for expedited loading and discharge of the mandrel plugs, for greater efficiency in mill operation.</p> |
