ROLL PASSES FOR ASYMMETRIC FORMING OF BREAKDOWNS OUT OF HARD-TO-FORM ALLOYS Russian patent published in 2003 - IPC

FIELD: plastic metal working; particularly, production of light-wall longitudinal electric welded tubes out of hard-to-form alloys, for instance, titanium alloys; roll forming in electric-weld pipe mills. SUBSTANCE: the first forming stand of asymmetric forming area consists of top and bottom rolls, which shape is asymmetric relative to vertical axis and which have horizontal axis of rotation; in so doing, left-hand half of both rolls has radius equal to radius of finished tube, while right-hand half of both rolls has radius equal to radius of crimp R1 regulated by mathematical expression; stand of guides incorporates left-hand and right-hand rolls having vertical axes of rotation and with shape of right-hand roll with radius equal to radius of finished tube and shape of left-hand roll with radius equal to radius of crimp R1 . If roll with crimping radius R1 in the first forming stand is located on left-hand side, in stand of guides this roll is located on right-hand side, and vice versa. EFFECT: production of tubes out of hard-to-form alloys with high geometric accuracy; reduction of internal residual stresses of breakdowns without usage of additional special equipment. 6 dwg _