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

• Published in: Steel research international Vol. 91; no. 9
• Main Authors: Cao, JianGuo, Xiong, HaiTao, Huang, XiaoHai, Zhao, QiuFang, Li, YanLin, Liu, ShiQuan
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.09.2020
• Subjects: Attenuation coefficients; Coils; Coils (strip); Computer simulation; Contour milling; Contour rolling; Ear; electrical steel; Electrical steels; Finite element method; Flatness; Hot rolling; Hot rolling mills; Industrial applications; mathematic models; Mathematical models; Optimization; profile and flatness control; Roll gap; Roll stacks; Rolling mills; schedule-free rolling; Schedules; shifting strategy; Sine waves; Strategy; Strip steel; Three dimensional models; Wear; work wear
• ISSN: 1611-3683; 1869-344X
• DOI: 10.1002/srin.201900662

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%. Based on the work roll wear and thermal contours models and a 3D finite‐element model of roll stacks and strip, the effects of the work roll wear contours on the loaded roll gap profile are analyzed. A variable stroke and step shifting strategy is developed based on the exponentially damped sinusoids function and is applied to the industrial mills.