METHOD OF ROTARY ROLLING-OUT OF ENVELOPMENTS FROM TUBULAR BILLETS AND TUBULAR BILLET TO PRODUCE ENVELOPMENTS THEREBY Russian patent published in 2010 - IPC B21D22/16 B21D51/16 

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming. Proposed method comprises deforming revolving tubular billet arranged on mandrel by deforming rolls. Tubular billet with lead-in cylindrical and conical sections. Billet is placed onto mandrel with clearances between its inner surface and mandrel and between lead-in cylindrical section outer surface and deforming rolls. Deforming rolls are fed into and removed from the billet at an angle. Deforming rolls feature profile with front and rear angles not smaller than inclination angle of tubular billet lead-in conical section and the angle of roll feed in/removing from the billet. Deforming is started with billet rotation when rolls come in contact with it. Deforming is terminated at the distance from the billet end making at least the billet thickness. Lead-in cylindrical section has diametre making 0.9-0.99 of the billet main section diametre, and length equal to 2-5 thicknesses of billet wall. Inner or outer surface of lead-in cylindrical section has face thrust that features thickness making 0.6-1.5 of billet wall thickness. Face thrust fairs with billet surface and end part edge along the radius.

EFFECT: higher accuracy of geometrical sizes, efficiency and utilisation factor.

6 cl, 5 dwg, 1 ex