Work Roll Shifting Strategy of Uneven “Cat Ear” Wear Control for Profile and Flatness of Electrical Steel in Schedule‐Free Rolling

Abstract

There are severe uneven “cat ear” wear contours of work rolls, the key factors to affect high‐quality profile and flatness control of electrical steel strips, in the schedule‐free rolling process with a large number of the same width strip rolling campaigns of hot rolling mills. The work roll wear prediction model, thermal roll contour model, and a 3D finite‐element model of roll stacks and strip are established using MATLAB and ABAQUS software. The effects of the work roll wear contour on the loaded roll gap profile within the entire rolling campaign are analyzed. A variable stroke and step (VSS) shifting strategy is developed based on the exponentially damped sinusoids function, which can get the smooth work roll wear contours. The main parameters including attenuation coefficient of stroke, the coil number and the attenuation coefficient of the first shifting cycle, and the initial phase avoiding repetition of the shifting position, are obtained by genetic optimization. The industrial application of the VSS shifting strategy gives remarkable results. The “cat ear” height value of local work roll wear contours is decreased by 67.3% and the high‐precision rate of crown from 25 to 40 μm of the electrical steel is increased by 22.5%.