METHOD FOR DEFORMING END PORTION OF TUBE AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 1998 - IPC

FIELD: plastic metal working. SUBSTANCE: method comprises steps of rotating tube blank around its lengthwise axis by means of rolls compressing tube wall, locally deforming end portion of tube blank by means of shaping rollers; additionally moving rotating tube blank in axial direction due to shifting its rotation axis in plane normal relative to plane passing through rotation axes of said rolls by angle $$$ determined according to formula: $$$=K arctg(L/$$$xD), where L- axial feed value, mm/revolution; D - mean diameter of tube, mm; K - empirical factor taking into account axial slip of tube blank. Apparatus includes drive roll mounted on spindle, backup roll joined with mechanism for moving it in cross direction, shaping roller, assembly for shifting axis of blank. Said assembly is in the form of rest mounted with possibility of moving in plane normal relative to plane passing through rotation axes of rolls. Said shaping roller is mounted in such a way that it is fixed against radial motion on backup or drive roll. Apparatus also includes additional shaping roller. Shaping rollers may be made monolithic with said drive and backup rolls. EFFECT: enlarged manufacturing possibilities due to less hazard of stability loss of tube blank and use of the same apparatus for reducing and expanding tube. 6 cl, 4 dwg