Novolipetsk Iron and Steel Works, Lipetsk, Russia

A. V. Morozov, Director of the Rolling Production Directorate
S. I. Mazur, Chief Investment Customer of the Office of the Managing Director
V. A. Pimenov, Cand. Eng., Head of Technological Projects, Directorate for Development of New Process Technologies, e-mail: pimenov_va@nlmk.com

The production of high-quality cold-rolled products places strict demands on the technical condition of rolling mill equipment, including its geometrical and geodetic characteristics. Based on many years of experience in operating cold rolling mill equipment, geometrical characteristics have been determined that have a significant impact on operating conditions, process stability, and product quality. The most significant characteristics of the stand units position in the vertical and horizontal planes, affecting the distribution of forces and tensions across the strip width, the angles of crossing of the roll axes are considered. The necessity of monitoring these parameters during operation, including conducting geodetic surveys, is shown. The calculation methods are proposed and the impact of geometric deviations on the rolling conditions and service life of replaceable equipment are assessed, including the asymmetry of forces and tensions across the strip width, axial loads on the roll bearings. Based on the results of the performed geodetic measurements, the angles of the roll axes crossing, axial loads and reduction in the service life of the bearings are estimated. Comparison of the estimates with the results of mill operation showed the adequacy of the proposed methods. The methods of compensating for the negative impact of geometric deviations are considered and their efficiency is shown when implemented on a multi-stand mill. Adjustment of the control and maintenance procedures for replaceable equipment, carried out on the basis of the results of the geodetic survey of the mill, made it possible to reduce the probability of roll bearing failure many times.

N. A. Dikarev (NLMK) and S. A. Goremykin (Neva Technology, St. Petersburg) took part in the work.

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