METHOD FOR CALIBRATING ROLLS OF REDUCTION TUBE ROLLING MILL Russian patent published in 1998 - IPC

FIELD: calibration of rolls of roll sets consisting of three rolls of multistand reduction mill for rolling tubes without mandrel. SUBSTANCE: in order to enhance roll calibration and to act upon metal yielding in such a way that to provide lowered local thickening of tube wall at reducing it in critical points along tube perimeter at least several sets of rolls arranged one after another in rolling direction have dimension of convexity 5 on lateral sides of roll groove 4 increasing by constant or the same percentage values. EFFECT: lowered local thickening of reduced tube wall in critical points along its perimeter. 4 cl, 2 dwg