SCREW ROLLING METHOD Russian patent published in 2007 - IPC B21B19/00 

FIELD: plastic working of metals, namely process for screw rolling of rods, mainly of alloyed metals and alloys.

SUBSTANCE: screw rolling method comprises steps of reducing blank in roll grooved pass restricted by drive rolls whose axes cross with rolling axis while displacing metal along rectilinear path on axis of blank and along helical paths in remained volume of blank. Reduction is realized at decelerating metal displacement, shortening length of helical paths in outer layer of blank while providing simultaneous acceleration of metal motion and increasing length of paths in inner layer. Thickness of outer layer of rolled blank consists 0.3 - 0.7 of its radius. Relation of linear compression deformation along helical paths on surface of blank to tension deformation along its axis is in range (-0.1) - (-0.5).

EFFECT: improved physical, mechanical and functional properties of rolled piece, possibility for producing from blank with chemically uniform structure rolled piece with double-layer structure.

4 dwg