TUBE COLD ROLLING METHOD AND COLD ROLLING MILL FOR PERFORMING THE SAME Russian patent published in 2004 - IPC

FIELD: equipment for making seamless cold rolled elongated tubes.

SUBSTANCE: method comprises steps of batch feeding of blank to deformation zone formed by means of two pairs of rolls; deforming first portion of tube by means of first and second pairs of rolls performing reciprocation motion relative to fixed mandrel; calibrating tube wall by thickness before deforming it between second pair of rolls at deformation degree 5 -15 % and calibration factor 2.0 - 2.5; rotating blank before forward stroke and before reverse stroke of rolling stand. Tube cold rolling mill includes housing, stand with rolling rolls having in necking portions gear wheels, stationary racks engaged with gear wheels, mechanism for reciprocation motion of stand, rotating and feeding apparatus. Stand with rolling rolls is provided with additional pair of rolls that may be shifted out of engagement; deformation zone is formed by two pairs of rolls with possibility of deforming blank onto cone mandrel along which are arranged: zones for reducing by diameter, zones for reducing wall by thickness, calibration zone and overlap zone in which metal is deformed by means of two pairs of rolls. It allows to calibrate tube wall in portion of overlapping reducing zones, and it is possible to make tubes of two sizes from blank of one size.

EFFECT: enhanced quality of rolled tubes due to lowered difference of wall thickness values.

2 cl, 3 dwg, 3 tbl