SCREW ROLLING METHOD AND APPARATUS FOR PERFORMING THE SAME Russian patent published in 2002 - IPC

FIELD: plastic metal working, namely rolled stock production, particularly processes and equipment for screw rolling. SUBSTANCE: method comprises steps of reducing billet between rolls in roll grooved pass defined by mutual approaching of contact surfaces of rolls whose axes are inclined relative to axis of billet performing rotation and translation motion between said surfaces; at reducing billet, decreasing spacing between contact surfaces of rolls and increasing effort of metal acting upon rolls; smoothly decreasing cross section area of billet at rate consisting 10-20% per one revolution in zone of deformation beginning; at rate 15-40% - in zone of mean deformation and at rate 1-5% - in outlet. Rolling stand includes stationary and moving flanges, chocks arranged in radial turnings of stationary flange, rolling rolls mounted in chocks; placed in stationary flange lead screws joined with chocks. Stand is provided with cartridges for placing chocks of each roll. Cartridge engages with moving flange along cone surface of flange having negative (relative to rolling direction) conicity angle equal to 10-20 degrees. Lead screws are secured to cartridges, they are spring-loaded and may move together with chocks normally relative to stand axis in radial turnings. Drive unit for moving flange is in the form of pressure screw. Lower roll may be mounted stationary; radial turnings for two upper rolls are inclined by 30 degrees relative to vertical axis. Their cartridges are provided with additional inserts for placing chocks mounted in cartridges and inclined by angle equal to 30 degrees relative to base of cartridges. Stationary flange may be in the form of holder embracing moving flange whose inner surface is cone one and corresponds to outer surface of each cartridge and whose outer surface is joined with inner surface of stationary flange by means of threaded joint. EFFECT: significantly enhanced accuracy of rolled blanks. 4 cl, 3 dwg