METHOD OF ROLLING HOLLOW BILLET ON MANDREL IN THREE-SHAFT HELICAL ROLLING MILL AND WORKING ROLL FOR IMPLEMENTATION THEREOF Russian patent published in 2020 - IPC B21B19/06 

FIELD: metal forming.

SUBSTANCE: group of inventions relates to metal forming, particularly, to production of seamless pipes, and can be used in rolling hollow workpieces with rolls on a mandrel in a helical rolling mill. Proposed method comprises gripping of hollow billet by rolls, deformation of hollow billet along diameter, deformation along wall, intensive deformation of wall by flange, calibration along diameter and wall. Possibility of obtaining wide-dimensioned range of obtained pipes from specified diameters of initial billet with reduction of size range of billets themselves is ensured by the fact that deformation of hollow billet along diameter is carried out with additional reduction by value ε_p, equal to 0.25…0.88 of total deformation. Working roll has a grip cone having a main portion adjacent to the crest and an additional portion with an inclination angle to the rolling axis of 5…15°. Roll has a rolling and calibrating cone.

EFFECT: technical result consists in increase in number of deformation cycles, which promotes study of metal structure of continuously cast billet.

2 cl, 4 dwg