METHOD OF PRODUCING BARRELS BY SCREW PIERCING Russian patent published in 2010 - IPC B21B19/04 

FIELD: process engineering.

SUBSTANCE: proposed method comprises straining the heated billet by driven rolls turned through feed angle, said rolls having monkey wall, inlet and outlet tapers, and mandrel with tapered pay-out section. Stable metal motion to mandrel pay-out section is provided for by creation of controlled quantitative interrelation between volume of metal in the center of strain between metal inlet into rolls and cross section of mandrel nose and volume of metal fed into strain center per mandrel half-turn when generating lines of mandrel pay-out section and roll outlet taper converge at 1.5…6.0°.

EFFECT: reduced defect formation, increased metal deformability in production of seamless tubes.

2 cl, 1 dwg, 1 ex