Roll pass design for 3-roll passes of mandrel-less tube reducing mills

摘要

The invention concerns a roll pass design system for the three-roll sets in a multi-stand mandrel-less pipe-reducing rolling mill. In order to improve the roll design so that the flow of material in the pipe is locally influenced such that less extensive local pipe wall thickening occurs at critical points over the pipe periphery during reduction, the size (a) of the preliminary curvature (b) of the calibre flanks (4) of at least a plurality of roll sets arranged successively in the rolling direction increases by constant or proportionally equal amounts.