Assessing the stability of rolling

By plotting histograms and calculating the variation coefficient of the primary drive's torque in the cells of a continuous rolling mill, the stability of the process may be assessed. The elastic torques and motor torques in cells 5-7 of the 1680 mill in strip rolling were measured simultaneously at OAO Zaporozhstal', and the results were statistically analyzed. The motor's electromagnetic torque reflects the frequency properties of the transient process in the mechanical system of the drive and the reaction to technological perturbations, such as variation in strip temperature. By superposition of the motor's torque histograms and calculation of the torque's variation coefficient, the stability of rolling in the cells of a continuous mill may be qualitatively and quantitatively estimated. Numerical estimates of the rolling stability are presented for strip batches with and without intermediate coiling devices. © 2013 Allerton Press, Inc.