METHOD FOR CALIBRATION OF STRAIGHT SEAM ELECTRICALLY WELDED TUBES Russian patent published in 2007 - IPC B21C37/30 

FIELD: plastic working of metals, in particular, calibration of welded straight seam tubes.

SUBSTANCE: method involves reducing welded profile of blank in drive passes with decreasing of reduction value from 2% in first stand of calibration mill to (0.3-0.5)% in straightening stand; setting alternating bending mode change ranges depending on relative curvature of profile parts by drive stands within the ranges: for peripheral and central parts - (1.33-1.05) for first and (0.95-0.91) second stands and mid portions (0.91-0.8) for first and (1.18-1.11) second stands. Method allows concrete reduction mode ranges and parameters of relative curvature of tubular blank dependent on revealed mode to be clearly determined and, accordingly, geometric parameters of process tool for concrete size of mill and predetermined grade of welded tube to be defined.

EFFECT: provision for effective combination of deformation procedures for reduction and alternating calibration of various parts of blank profile by sizes of mill stands.

2 dwg, 6 tbl, 1 ex