METHOD OF ROLLING PIPES WITH INCREASED ACCURACY Russian patent published in 2023 - IPC B21B17/14 B21B37/78 

FIELD: rolling of high precision pipes.

SUBSTANCE: compression is carried out along the outer diameter of the pipe in three-roll stands of a multi-stand mandrelless longitudinal rolling mill. In the last two stands of the mill, the rolls form a calibre with an ovality value of not more than 1.02. In the last stand of the mill, the roll convergence relative to their nominal position corresponds to the condition e_i≤|α⋅D_nom+W_i+H_i+e_i-1-W_i-1-B_i|, where e_i is the convergence of the last stand relative to the nominal position, α is the dimensionless coefficient, the value of which corresponds to the range of 0.00303-0.00305, D_nom is the target nominal value of the outer diameter of the manufactured pipe in the cold state, W_i is the value of the maximum wear of the rolls of the last stand along the top of the pass, H_i is half the nominal height of the pass of the last stand, e_i-1 is the value of convergence of the rolls of the penultimate stand relative to the nominal position, W_i-1 is the value of the maximum wear of the rolls of the penultimate stand along the top of the calibre, B_i is half the nominal width of the calibre in the last stand.

EFFECT: accuracy of the outer diameter of the manufactured pipes is increased.

4 cl, 1 dwg, 1 tbl